It's hard to ionize ordinary hydrogen, and even harder to ionize nitrogen.
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Several types of electric rockets use electricity to ionize propellant.
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Those particles can ionize the hydrogen; they can heat it up.
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And those new stars ionize clouds of hydrogen, which look like bubbles.
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This leads atoms inside a painting to ionize and emit electromagnetic waves of their own.
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Since 2013, scientists have suspected they gave off enough energy to ionize hydrogen floating between galaxies.
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When the muons zip through the alcohol cloud, they ionize (charge) the air they pass through.
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If enough atoms are present they can ionize pockets of air and form a plasma, or charged gas, that emits light.
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This means they can ionize our poor DNA nucleotides , ripping them apart and occasionally leading to uncontrollable replication errors (aka, cancer).
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That's a type of "non-ionizing" radiation, since it doesn't carry enough energy to "ionize" — or strip electrons from atoms and molecules.
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The cosmic rays would have been enough to ionize the planet's troposphere, possibly contributing to a minor mass extinction linked to global cooling.
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And, with the star obscured by a layer of dust from the ejected matter, it's not supplying the necessary energy to ionize those elements.
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Made with real crystals from the mountains, these lamps give off a warm, soothing glow and are said to ionize the air for a better sleep at night.
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At the point where the water hits the plate, this generates a lot of electrons flowing from the plate to the surface where they ionize the gases at the surface.
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The barium cloud will ionize quickly into a purplish red color, illuminating the trajectories of charged particles in the ionosphere, while the strontium and cupric-oxide vapors reveal the motions of neutral particles.
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The catch is that for photons to escape these galaxies and go on to ionize atoms, they needed to avoid all of the neutral hydrogen atoms likely to be calling a star-forming galaxy home.
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The charged muons ionize the gas and the signal is carried to readout by the wires.
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As positrons are positively charged particles they can also directly ionize an atom through Coulomb interactions.
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Used to ionize gas in the upper atmosphere, they provide telescope operators with a target to calibrate their instruments.
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Ion thrusters ionize a neutral gas and create thrust by accelerating the ions (or the plasma) by electric and/or magnetic fields.
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They are often referred to as post-AGB stars, although that category also includes stars that will never ionize their ejected matter.
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Electrons leave the cathode with an energy of about 1 eV, which is not enough to ionize or excite atoms, leaving a thin dark layer next to the cathode.
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These metastable helium species can ionize all compounds with the exception of neon which has a bigger ionization potential of 21.56 eV. As components elute from the GC's column they collide with the metastable helium ions, which then ionize the components. The ions produce an electric current, which is the signal output of the detector. The greater the concentration of the component, the more ions are produced, and the greater the current.
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The setup is quite similar to today's AMS system, with the sample being introduced through a small steel capillary into the ion source region. The sample would ionize after striking a hot rhenium filament. The resulting ions were separated in a magnetic sector and detected by an electron multiplier. The method could only ionize elements with ionization potentials below the work function of the filament (~8 eV), typically alkali and alkaline earth metal.
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O type and B type stars are a classification of stars that strongly emit ultraviolet (UV) radiation. The UV radiation causes the surrounding cloud of hydrogen gas to ionize, forming H II regions. The gas does not ionize evenly throughout the cloud, therefore there are clumps of denser gas scattered throughout the cloud. These dense clumps are called evaporating gaseous globules (EGGs), and they are the starting point for the formation of an elephant trunk.
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When necessary, these anodes can temporarily be switched into impressed current mode to accelerate ion exchanges, so as to dechlorinate or ionize the concrete in the immediate vicinity of the rebars.
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VASIMR, short for Variable Specific Impulse Magnetoplasma Rocket, uses radio waves to ionize a propellant into a plasma. Then, a magnetic field accelerates the plasma from the rocket engine, generating thrust. The VASIMR is being developed by Ad Astra Rocket Company, headquartered in Houston, TX. A Nova Scotia, Canada-based company Nautel, is producing the 200 kW RF generators required to ionize the propellant. Some component tests and "Plasma Shoot" experiments are performed in a Liberia, Costa Rica laboratory.
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Signal intensity may be dependent on many factors, especially the nature of the molecules being analyzed and how they ionize. The efficiency of ionization varies from molecule to molecule and from ion source to ion source. For example, in electrospray sources in positive ion mode a quaternary amine will ionize exceptionally well whereas a large hydrophobic alcohol will most likely not be seen no matter how concentrated. In an EI source these molecules will behave very differently.
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Atmospheric pressure photoionization uses a source of photons, usually a vacuum UV (VUV) lamp, to ionize the analyte with single photon ionization process. Analogous to other atmospheric pressure ion sources, a spray of solvent is heated to relatively high temperatures (above 400 degrees Celsius) and sprayed with high flow rates of nitrogen for desolvation. The resulting aerosol is subjected to UV radiation to create ions. Atmospheric pressure laser ionization uses UV laser light sources to ionize the analyte via MPI.
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Ionization energy represents a large percentage of the energy needed to run ion drives. The ideal propellant is thus easy to ionize and has a high mass/ionization energy ratio. In addition, the propellant should not erode the thruster to any great degree to permit long life; and should not contaminate the vehicle.Rocket Propulsion Elements — Sutton & Biblarz 7th edition Many current designs use xenon gas, as it is easy to ionize, has a reasonably high atomic number, is inert and causes low erosion.
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The abundance of the H- ion is proportional to the density of free electrons, which, in turn, is higher if there are more metals because metals are easier to ionize than hydrogen or helium.
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Alpha decay is much more easily shielded against than other forms of radioactive decay. Static eliminators typically use polonium-210, an alpha emitter, to ionize the air, allowing the 'static cling' to dissipate more rapidly.
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In the latter case, there are not enough UV photons being emitted by the central star to ionize all the surrounding gas, and an ionization front propagates outward into the circumstellar envelope of neutral atoms.
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The most common use of electron guns is in cathode ray tubes, which were widely used in computer and television monitors until flat-screen displays rendered them obsolete. An electron gun can also be used to ionize particles by adding electrons to, or removing electrons from an atom. This technology is sometimes used in mass spectrometry in a process called electron ionization to ionize vaporized or gaseous particles. More powerful electron guns are used for welding, metal coating, 3D metal printers, metal powder production and vacuum furnaces.
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The RIS process can be used to ionize all elements on the periodic table, except helium and neon, using available lasers. In fact, it is possible to ionize most elements with a single laser set-up, thus enabling rapid switching from one element to another. In the early days, optical schemes from RIMS have been used to study over 70 elements and over 39 elements can be ionized with a single laser combination using a rapid computer-modulated framework that switches elements within seconds.
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Any charged particle with mass can ionize atoms directly by fundamental interaction through the Coulomb force if it carries sufficient kinetic energy. This includes atomic nuclei, electrons, muons, charged pions, protons, and energetic charged nuclei stripped of their electrons. When moving at relativistic speeds these particles have enough kinetic energy to be ionizing, but relativistic speeds are not required. For example, a typical alpha particle is ionizing, but moves at about 5% c, and an electron with 33 eV (enough to ionize) moves at about 1% c.
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Usually, a young star will ionize part of the same cloud from which it was born, although only massive, hot stars can release sufficient energy to ionize a significant part of a cloud. In many emission nebulae, an entire cluster of young stars is doing the work. The nebula's color depends on its chemical composition and degree of ionization. Due to the prevalence of hydrogen in interstellar gas, and its relatively low energy of ionization, many emission nebulae appear red due to the strong emissions of the Balmer series.
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Several photons of energy below the ionization threshold may actually combine their energies to ionize an atom. This probability decreases rapidly with the number of photons required, but the development of very intense, pulsed lasers still makes it possible. In the perturbative regime (below about 1014 W/cm2 at optical frequencies), the probability of absorbing N photons depends on the laser-light intensity I as IN . Above threshold ionization (ATI) is an extension of multi-photon ionization where even more photons are absorbed than actually would be necessary to ionize the atom.
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The region at which radiation becomes considered as "ionizing" is not well defined, since different molecules and atoms ionize at different energies. The usual definitions have suggested that radiation with particle or photon energies less than 10 electronvolts (eV) be considered non-ionizing. Another suggested threshold is 33 electronvolts, which is the energy needed to ionize water molecules. The light from the Sun that reaches the earth is largely composed of non-ionizing radiation, since the ionizing far-ultraviolet rays have been filtered out by the gases in the atmosphere, particularly oxygen.
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D. Beckey develops field desorption. :1974 ::Comisarow and Marshall develop Fourier Transform Ion Cyclotron Resonance mass spectrometry. :1976 ::Ronald MacFarlane and co-workers develop plasma desorption mass spectrometry. :1984 ::John Bennett Fenn and co-workers use electrospray to ionize biomolecules.
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Neutrons are neutral and thus do not respond to electric fields. This makes it hard to direct their course towards a detector to facilitate detection. Neutrons also do not ionize atoms except by direct collision, so gaseous ionization detectors are ineffective.
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NGC 6914 is a reflection nebula located at approximately 6,000 light-years away in the constellation of Cygnus, and was discovered by Édouard Stephan on August 29, 1881. Ultraviolet radiation from stars in the Cygnus OB2 association ionize the nebula's hydrogen.
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When power is applied, if there is sufficient voltage to ionize the argon, the ionized argon gas will strike a small arc between the starting electrode and the adjacent main electrode. As the ionized argon conducts, the heat from its arc vaporizes the liquid mercury; next, the voltage between the two main electrodes will ionize the mercury gas. An arc initiates between the two main electrodes and the lamp will then radiate mainly in the ultraviolet, violet and blue emission lines. Continued vaporization of the liquid mercury increases the arc tube pressure to between 2 and 18 bar, depending on lamp size.
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APPI can ionize both polar and nonpolar species, and an APPI spectrum can be generated in just a few seconds. However, APPI ionizes a broad range of compound classes and produces both protonated and molecular ion peaks, resulting in a complex mass spectrum.
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Within the discharge plasma, the sample evaporates, atomizes, and ionizes via electron impact. The total ion current may be optimized by adjusting the distance between the electrodes. This mode of ionization can be used to ionize conducting, semi-conducting, and non-conducting samples.
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They are thus extremely energetic, which means that they can ionize neutral atoms. Neutral propellant is pumped into the chamber and is ionized by the trapped electrons. Positive ions and electrons are then ejected from the thruster as a quasineutral plasma, creating thrust.
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The Auger effect allows one to multiply ionize an atom with a single photon. There are rather strict selection rules as to the electronic configurations that can be reached by excitation by light — however there are no such rules for excitation by collision processes.
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G. C. SchmidtSchmidt, G. C. (1898) Wied. Ann. Uiv. p. 708. and O. Knoblauch compiled a list of these substances. Under certain circumstances light can ionize gases, first reported by Philipp Lenard in 1900. In 1899, J. J. Thomson investigated ultraviolet light in Crookes tubes.
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The venting of atmosphere continues unabated into interstellar space, but when the outer surface of the exposed core reaches temperatures exceeding about 30,000 K, there are enough emitted ultraviolet photons to ionize the ejected atmosphere, causing the gas to shine as a planetary nebula.
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The other gas, called a quench gas, has to have lower ionization potential than the first excited state of the noble gas. The energy of the excited, but neutral, noble gas atoms then can ionize the quench gas particles by energy transfer via collisions; known as the Penning effect. A very common Penning mixture of about 98–99.5% of neon with 0.5–2% of argon is used in some neon lamps, especially those rated at 110 volts. The mixture is easier to ionize than either neon or argon alone, and lowers the striking voltage at which the tube becomes conductive and starts producing light.
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When the pressure–gap product pd is high, an electron will collide with many different gas molecules as it travels from the cathode to the anode. Each of the collisions randomizes the electron direction, so the electron is not always being accelerated by the electric field—sometimes it travels back towards the cathode and is decelerated by the field. Collisions reduce the electron's energy and make it more difficult for it to ionize a molecule. Energy losses from a greater number of collisions require larger voltages for the electrons to accumulate sufficient energy to ionize many gas molecules, which is required to produce an avalanche breakdown.
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This method can only be used to ionize conducting samples, e.g. metals. The high-voltage rf spark source is the one that was used in commercial SSMS instruments due to its ability to ionize both conducting and non-conducting materials. Typically, samples are physically incorporated into two conductive electrodes between which an intermittent (1 MHz) high-voltage (50-100 kV using a Tesla transformer) electric spark is produced, ionizing the material at the tips of the pin-shaped electrodes. When the pulsed current is applied to the electrodes under ultra-high vacuum, a spark discharge plasma occurs in the spark gap in which ions are generated via electron impact.
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The dihydrogen ion is formed in nature by the interaction of cosmic rays and the hydrogen molecule. An electron is knocked off leaving the cation behind. :H2 \+ cosmic ray → + e− \+ cosmic ray. Cosmic ray particles have enough energy to ionize many molecules before coming to a stop.
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Ionize is a free multilingual Content Management System based on CodeIgniter written in PHP. It was developed by a group of webdesigners and is aimed to be highly flexible and modular, yet easy to use for end users. It requires a working Apache and MySQL installation.
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Some common reagent gases include: methane, ammonia, and isobutane. Inside the ion source, the reagent gas is present in large excess compared to the analyte. Electrons entering the source will preferentially ionize the reagent gas. The resultant collisions with other reagent gas molecules will create an ionization plasma.
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The ECR ion source makes use of the electron cyclotron resonance to ionize a plasma. Microwaves are injected into a volume at the frequency corresponding to the electron cyclotron resonance, defined by the magnetic field applied to a region inside the volume. The volume contains a low pressure gas.
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In many cases photoionization is believed to be this source. In nitrogen-oxygen gas mixtures with high oxygen concentrations, excited nitrogen emits UV photons which subsequently ionize oxygen. In pure nitrogen or in nitrogen with small oxygen admixtures, the dominant production mechanism of photons, however, is the Bremsstrahlung process.
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Voltage-regulator tube in operation. Low-pressure gas within tube glows due to current flow. Some special-purpose tubes are constructed with particular gases in the envelope. For instance, voltage-regulator tubes contain various inert gases such as argon, helium or neon, which will ionize at predictable voltages.
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If the sample is not homogeneous, then the neutral ions will ionize only the surface, which does not provide an accurate detection for the substance. The scanning of the FTICR allows for the detection of complex compounds with high resolution, which leads to the ability to analyze elemental composition.
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Atomic vapor laser isotope separation employs specially tuned lasersF. J. Duarte and L.W. Hillman (Eds.), Dye Laser Principles (Academic, New York, 1990) Chapter 9. to separate isotopes of uranium using selective ionization of hyperfine transitions. The technique uses lasers tuned to frequencies that ionize 235U atoms and no others.
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The ionization energy of HS is 10.4219 eV. The reduction potential to go to HS− is 0.92 eV. HS• in water can ionize to S•− and H+. The S•− can catalyze a cis-trans conversion in lipids. The interatomic distance between sulfur and hydrogen in the radical is 0.134 nm.
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Diagram of a Krytron A krytron has four electrodes. Two are a conventional anode and cathode. One is a keep-alive electrode, arranged to be close to the cathode. The keep-alive has a low positive voltage applied, which causes a small area of gas to ionize near the cathode.
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Streamer discharges into the air from the high voltage terminal of a large Tesla coil. The streamers form at the end of a pointed rod projecting from the terminal. The high electric field at the pointed end causes the air to ionize there. Video clip of streamers from a Tesla coil.
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The electrons travel through the gauge and ionize gas molecules around them. The resulting ions are collected at a negative electrode. The current depends on the number of ions, which depends on the pressure in the gauge. Hot cathode gauges are accurate from 10−3 Torr to 10−10 Torr.
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The first ionization potential of neptunium was measured to be at most in 1974, based on the assumption that the 7s electrons would ionize before 5f and 6d; more recent measurements have refined this to 6.2657 eV.David R. Lide (ed), CRC Handbook of Chemistry and Physics, 84th Edition. CRC Press.
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In the hot cathode version an electrically heated filament produces an electron beam. The electrons travel through the gauge and ionize gas molecules around them. The resulting ions are collected at a negative electrode. The current depends on the number of ions, which depends on the pressure in the gauge.
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Violet hue can occur when the spectrum contains emission lines of atomic hydrogen. This may happen when the air contains high amount of water, e.g. with lightnings in low altitudes passing through rain thunderstorms. Water vapor and small water droplets ionize and dissociate easier than large droplets, therefore have higher impact on color.
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At Linköping University, Sweden, the inert gas is being utilized in a vacuum chamber in which plasma is introduced to ionize metallic films. This process results in a film usable for manufacturing computer processors. The new process would eliminate the need for chemical baths and use of expensive, dangerous and rare materials.
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A duoplasmatron is a type of glow discharge ion source that consists of a cathode (hot cathode or cold cathode) that produces a plasma that is used to ionize a gas. Duoplasmatrons can produce positive or negative ions. Duoplasmatrons are used for secondary ion mass spectrometry., ion beam etching, and high-energy physics.
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Neutrons can elastically scatter off nuclei, causing the struck nucleus to recoil. Kinematically, a neutron can transfer more energy to a light nucleus such as hydrogen or helium than to a heavier nucleus. Detectors relying on elastic scattering are called fast neutron detectors. Recoiling nuclei can ionize and excite further atoms through collisions.
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The breakthrough for large molecule laser desorption ionization came in 1987 when Koichi Tanaka of Shimadzu Corporation and his co-workers used what they called the "ultra fine metal plus liquid matrix method" that combined 30 nm cobalt particles in glycerol with a 337 nm nitrogen laser for ionization. Using this laser and matrix combination, Tanaka was able to ionize biomolecules as large as the 34,472 Da protein carboxypeptidase-A. Tanaka received one-quarter of the 2002 Nobel Prize in Chemistry for demonstrating that, with the proper combination of laser wavelength and matrix, a protein can be ionized. Karas and Hillenkamp were subsequently able to ionize the 67 kDa protein albumin using a nicotinic acid matrix and a 266 nm laser.
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DMSA may be prepared by reacting acetylenedicarboxylic acid with sodium thiosulfate or thioacetic acid followed by hydrolysis. The dimethyl ester is also known. Meso 2,3-dimercaptosuccinic acid binds to "soft" heavy metals such as Hg2+ and Pb2+, mobilizing these ions for excretion. It binds to metal cations through the thiol groups, which ionize upon complexation.
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Peptides that are not expected to change in their expression levels in different biological samples may be used for this purpose. However, not all peptides ionize well and therefore the choice of candidates should be done after an initial study which should only characterize the protein content of the biological samples that will be investigated.
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In multi-photon ionization (MPI), several photons of energy below the ionization threshold may actually combine their energies to ionize an atom. Resonance-enhanced multiphoton ionization (REMPI) is a form of MPI in which one or more of the photons accesses a bound-bound transition that is resonant in the atom or molecule being ionized.
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Hydroiodic acid (or hydriodic acid) is a highly acidic aqueous solution of hydrogen iodide (H I) (concentrated solution usually 48 - 57% HI). It is the second strongest hydrohalic acid, after hydroastatic acid. Hydroiodic acid is a commonly used chemical reagent and is one of the strong acids that ionize completely in an aqueous solution.
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Radioactive material from the ground and galactic cosmic rays ionize a small fraction of the atmospheric gas within the lower and middle atmosphere and make the gas electrically conducting. Electrons quickly attach to neutral particles forming negative ions. The positive ions are mostly singly charged. The electric conductivity depends on the mobility of the ions .
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The circularized near-threshold Rydberg state is more likely to undergo a core photoabsorption than to absorb a photon and directly ionize the Rydberg state. PIRI extends the near-threshold spectroscopic techniques to allow access to the electronic states (including dissociative molecular states and other hard to study systems) as well as the vibrational states of molecular ions.
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Am. Ind. Hyg. Assoc. J., 51:326-330 (1990). This attenuation is due to the ability of water, methane, and other compounds with high ionization energies to absorb the photons emitted by the UV lamp without leading to the production of an ion current. This reduces the number of energetic photons available to ionize target analytes.
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The technique was first reported by Beckey in 1969.Beckey H.D. Field ionization mass spectrometry. Research/Development, 1969, 20(11), 26 It is also the first ionization method to ionize nonvolatile and thermally labile compounds. One major difference of FD with other ionization methods is that it does not need a primary beam to bombard a sample.
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In solution, it can ionize, producing the lactate ion . Compared to acetic acid, its pKa is 1 unit less, meaning lactic acid is ten times more acidic than acetic acid. This higher acidity is the consequence of the intramolecular hydrogen bonding between the α-hydroxyl and the carboxylate group. Lactic acid is chiral, consisting of two enantiomers.
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Ernst Stuhlinger, "Why Explore Space?". Retrieved 2012-02-08 Stuhlinger spent much of his spare time developing designs for solar-powered spacecraft. The most popular of those designs relied on ion thrusters, which ionize either caesium or rubidium vapor and accelerate the positively charged ions through gridded electrodes. The spacecraft would be powered by one kilowatt of solar energy.
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Some metal hydroxides, like alkali metal hydroxides, ionize completely when dissolved, so that is why they are known as strong bases. Their pH is above 7, labeling them as bases. Since ions conduct electricity, alkali hydroxides carry electricity very well when they are dissolved. Some metal hydroxides are weak electrolytes and dissolve only partially in aqueous solution.
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The hydroxide ion forms salts, some of which dissociate in aqueous solution, liberating solvated hydroxide ions. Sodium hydroxide is a multi-million-ton per annum commodity chemical. A hydroxide attached to a strongly electropositive center may itself ionize, liberating a hydrogen cation (H+), making the parent compound an acid. The corresponding electrically neutral compound HO• is the hydroxyl radical.
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The atomic vapor laser isotope separation (AVLIS) process uses the hyperfine splitting between optical transitions in uranium-235 and uranium-238 to selectively photo-ionize only the uranium-235 atoms and then separate the ionized particles from the non- ionized ones. Precisely tuned dye lasers are used as the sources of the necessary exact wavelength radiation.
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Sterilization can be achieved using electromagnetic radiation, such as Ultraviolet light, X-rays and gamma rays, or irradiation by subatomic particles such as by electron beams.Trends in Radiation Sterilization of Health Care Products, IAEA, Vienna,24 September 2008 Electromagnetic or particulate radiation can be energetic enough to ionize atoms or molecules (ionizing radiation), or less energetic (non- ionizing radiation).
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Atmospheric pressure laser ionization is an atmospheric pressure ionization method for mass spectrometry (MS). Laser light in the UV range is used to ionize molecules in a resonance-enhanced multiphoton ionization (REMPI) process. It is a selective and sensitive ionization method for aromatic and polyaromatic compounds. Atmospheric photoionization is the latest in development of atmospheric ionization methods.
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By observing the intensity of the emission, the concentration of atoms of that type can be determined. Energy gained through collisions can also ionize the sample atoms. The ions can then be detected by mass spectrometry. In this case, it is the mass of the ions that identify the element and the number of ions that reflect the concentration.
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In such experiments, as above, a cylindrical coil produces a uniform axial magnetic field and gas is introduced and ionized, creating a background plasma. Neutral particles are then injected into the plasma. They ionize and the heavier, positively-charged particles form a current ring which reverses the magnetic field. Spheromaks are FRC-like configurations with finite toroidal magnetic field.
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A plasma is formed along the axis of the anode which traps electrons which, in turn, ionize gas in the source. The ions are extracted through the exit cathode. Under normal operation, the ion species produced by the Penning source are over 90% molecular ions. This disadvantage is however compensated for by the other advantages of the system.
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Electrical breakdown occurs within a gas when the dielectric strength of the gas is exceeded. Regions of intense voltage gradients can cause nearby gas to partially ionize and begin conducting. This is done deliberately in low pressure discharges such as in fluorescent lights. The voltage that leads to electrical breakdown of a gas is approximated by Paschen's Law.
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The large amounts of gas mean that very massive stars are formed. Young, hot stars ionize the gas (mainly hydrogen) around them, creating H II regions. Groups of very hot stars are known as OB associations. These stars burn very bright and very fast, and are quite likely to explode at the end of their lives as supernovae.
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The cosmic background hard radiation will ionize the rocket's hull over time and poses a health threat. Also, gas plasma interactions may cause space charge. The major interaction of concern is differential charging of various parts of a spacecraft, leading to high electric fields and arcing between spacecraft components. This can be resolved with well placed plasma contactor.
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For spark ionization, there exist two ion sources: the low-voltage direct-current (DC) arc source and the high-voltage radio-frequency (rf) spark source. The arc source has better reproducibility and the ions produced have a narrower energy spread compared to the spark source; however, the spark source has the ability to ionize both conducting and non-conducting samples while the arc source can only ionize conducting samples. In the low-voltage DC arc source, a high voltage is applied to the two conducting electrodes to initiate the spark, followed by application of a low-voltage direct current to maintain an arc between the spark gap. The duration of the arc is usually only a few hundred microseconds to prevent overheating of the electrodes, and it repeated 50-100 times per second.
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These researchers found that the amino acid alanine could be ionized more easily if it was mixed with the amino acid tryptophan and irradiated with a pulsed 266 nm laser. The tryptophan was absorbing the laser energy and helping to ionize the non-absorbing alanine. Peptides up to the 2843 Da peptide melittin could be ionized when mixed with this kind of “matrix”.
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Many hypotheses have been proposed. One theory postulates that showers of relativistic electrons are created by cosmic rays and are then accelerated to higher velocities via a process called runaway breakdown. As these relativistic electrons collide and ionize neutral air molecules, they initiate leader formation. Another theory involves locally enhanced electric fields being formed near elongated water droplets or ice crystals.
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The basic element of the common ion pump is a Penning trap.Cambers, A., "Modern Vacuum Physics", CRC Press (2005) A swirling cloud of electrons produced by an electric discharge is temporarily stored in the anode region of a Penning trap. These electrons ionize incoming gas atoms and molecules. The resultant swirling ions are accelerated to strike a chemically active cathode (usually titanium).
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When the electric field reaches a value in the order of 109 V/m, the atoms at the tip of the cusps spontaneously ionize and an ion jet is extracted by the electric field, while the electrons are rejected in the bulk of the liquid. An external source of electrons (neutralizer) provides negative charges to maintain global electrical neutrality of the thruster assembly.
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Collectively, these electrons are defined as delta radiation when they have sufficient energy to ionize further atoms through subsequent interactions on their own. Delta rays appear as branches in the main track of a cloud chamber (See Figs. 1,2). These branches will appear nearer the start of the track of a heavy charged particle, where more energy is imparted to the ionized electrons.
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A metal ion in the active site participates in catalysis by coordinating charge stabilization and shielding. Because of a metal's positive charge, only negative charges can be stabilized through metal ions. However, metal ions are advantageous in biological catalysis because they are not affected by changes in pH. Metal ions can also act to ionize water by acting as a Lewis acid.
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Different types of electromagnetic radiation The total absorption coefficient of lead (atomic number 82) for gamma rays, plotted versus gamma energy, and the contributions by the three effects. Here, the photoelectric effect dominates at low energy. Above 5 MeV, pair production starts to dominate. Even though photons are electrically neutral, they can ionize atoms directly through the photoelectric effect and the Compton effect.
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At energies beyond 100 keV, photons ionize matter increasingly through the Compton effect, and then indirectly through pair production at energies beyond 5 MeV. The accompanying interaction diagram shows two Compton scatterings happening sequentially. In every scattering event, the gamma ray transfers energy to an electron, and it continues on its path in a different direction and with reduced energy.
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Hydrogen molecular ion clusters can be formed through different kinds of ionizing radiation. High energy electrons capable of ionizing the material can perform this task. When hydrogen dissolved in liquid helium is irradiated with electrons their energy must be sufficient to ionize helium to produce significant hydrogen clusters. Irradiation of solid hydrogen by gamma rays or X-rays also produces .
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The matrix must absorb at the laser wavelength and ionize the analyte. Matrix selection and solvent system relies heavily upon the analyte class desired in imaging. The analyte must be soluble in the solvent in order to mix and recrystallize the matrix. The matrix must have a homogeneous coating in order to increase sensitivity, intensity, and shot-to- shot reproducibility.
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For strong electrolytes, a single reaction arrow shows that the reaction occurs completely in one direction, in contrast to the dissociation of weak electrolytes, which both ionize and re-bond in significant quantities.Brown, Theodore L. Chemistry: The Central Science, 9th edition. :Strong electrolyte(aq) -> Cation+(aq) + Anion−(aq) Strong electrolytes conduct electricity only when molten or in aqueous solutions. Strong electrolytes break apart into ions completely.
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These enter and ionize the fill gas. This is necessary as the low-pressure gas in the tube has little interaction with higher energy photons. However, as photon energies decrease to low levels there is greater gas interaction and the direct gas interaction increases. At very low energies (less than 25 KeV) direct gas ionisation dominates and a steel tube attenuates the incident photons.
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Since star formation does not happen immediately, the stars are slightly behind the density waves. The hot OB stars that are created ionize the gas of the interstellar medium, and form H II regions. These stars have relatively short lifetimes, however, and expire before fully leaving the density wave. The smaller, redder stars do leave the wave, and become distributed throughout the galactic disk.
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A Tesla coil will pass high-frequency current through the tube, and since it has a high voltage as well, the gases within the tube will ionize and emit light. This also works with plasma globes. Capacitive coupling with high-voltage power lines can light a lamp continuously at low intensity, depending on the intensity of the electric field, as shown in the image on the right.
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This accelerates space plasma electrons which ionize neutral expellant flow from the contactor. If electron collection currents are high and/or ambient electron densities are low, the sheath at which electron current collection is sustained simply expands or shrinks until the required current is collected. In addition, the geometry affects the emission of the plasma from the HC as seen in the below figure.
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SuWt 2 is a planetary nebula viewed almost edge-on in the constellation of Centaurus. It is believed that high UV radiations from an undiscovered white dwarf ionizes this nebula. Currently, there is a binary system consisting of two A-type main-sequence stars whose radiations are not enough to photo-ionize the surrounding nebula. The nebula is easily obscured by the brighter star, HD 121228.
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The electrons in the gas are accelerated by the RF field and can ionize the gas directly or indirectly by collisions, producing secondary electrons. When the electric field is strong enough, it can lead to what is known as electron avalanche. After avalanche breakdown, the gas becomes electrically conductive due to abundant free electrons. Often it accompanies light emission from excited atoms or molecules in the gas.
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In accelerator physics, ionization cooling is a process for reducing the emittance of ("cooling") a charged particle beamG.I. Budker, in: Proceedings of 15th International Conference on High Energy Physics, Kiev, 1970A.N. Skrinsky, Intersecting storage rings at Novosibirsk, in: Proceedings of Morges Seminar, 1971 Report CERN/D.PH II/YGC/mng by passing the particles through some material, reducing their momentum as they ionize atomic electrons in the material.
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This technique alone is not highly efficient for different varieties of molecules, particularly those that are not easily protonated or deprotonated. In order to completely ionize samples, dopant molecules must help. The gaseous solvent can also undergo photoionization and act as an intermediate for ionization of the sample molecules. Once dopant ions are formed, proton transfer can occur with the sample, creating more sample ions.
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That is, all slow electrons in the gas emanating either from the ionizing BSE or directly from the specimen (i.e. the SE) are multiplied in an avalanche form. The energy imparted on the traveling slow electrons by the external electrode field is sufficient to ionize the gas molecules through successive (cascade) collisions. The discharge is controlled in proportion by the applied electrode bias below the breakdown point.
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Electrons entering the source with energy around 200-500 eV will preferentially ionize the reagent gas. Then, the ion/molecule reactions produces more stable reagent ions and the resultant collisions with other reagent gas molecules will create an ionization plasma. Positive and negative ions of the analyte are formed by reactions with this plasma. The following reactions are possible with methane as the reagent gas.
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Interstellar space contains very small amounts of hydrogen. A fast-moving sail would ionize this hydrogen by accelerating the electrons in one direction and the oppositely charged protons in the other direction. The energy for the ionization and cyclotron radiation would come from the spacecraft's kinetic energy, slowing the spacecraft. The cyclotron radiation from the acceleration of particles would be an easily detected howl in radio frequencies.
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The device having been made in a clear glass tube in early experiments uses induction to ionize the gases and the field made by ionized gases to energize ion tube coils. The effect is similar to pyroelectric fusion but instead of pyroelectric crystals stripping the electrons from hydrogen atoms it is a high voltage induced electromagnetic field of coils and electrostatic induction of the ionized gas.
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The short-lived blue stars created in these regions emit copious amounts of ultraviolet light that ionize the surrounding gas. H II regions—sometimes several hundred light-years across—are often associated with giant molecular clouds. They often appear clumpy and filamentary, sometimes showing intricate shapes such as the Horsehead Nebula. H II regions may give birth to thousands of stars over a period of several million years.
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It is realizable on a laboratory scale (table-top systems) as opposed to large free electron-laser facilities. High harmonic generation in atoms is well understood in terms of the three-step model (ionization, propagation, and recombination). Ionization: The intense laser field modifies the Coulomb potential of the atom, electron tunnels through the barrier and ionize. Propagation: The free-electron accelerates in the laser field and gains momentum.
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The copper rod is the anode and the item is the cathode. This current flow causes the copper to ionize, become oxidized which means each atom becomes positively charged by losing an electron. As the copper ions dissolve into the water, they form a coordination complex with salts already present. The copper then physically flows to the item, where it is reduced to the metallic state by gaining electrons.
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A weak base is one which does not fully ionize in an aqueous solution, or in which protonation is incomplete. For example, ammonia transfers a proton to water according to the equation :NH_3(aq) + H_2O(l) \rightleftharpoons NH_4^+(aq) + OH^-(aq) The equilibrium constant for this reaction at 25 °C is 1.8 x 10−5, so that the extent of reaction or degree of ionization is quite small.
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The fact that carbon and silicone have similar, but also dissimilar, characteristics triggered the interest in substituting carbon with silanediol as a central, zinc chelating group. Silicone forms a dialkylsilanediol compound that is sufficiently hindered so the formation of a siloxane polymer does not occur. Silanediols are more stable than carbon diols so they are expected to have longer half-life. Silanediols are also neutral at physiological pH (do not ionize).
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Germicidal lamps contain no phosphor at all, making them mercury vapor gas discharge lamps rather than fluorescent. Their tubes are made of fused quartz transparent to the UVC light emitted by the mercury discharge. The 254 nm UVC emitted by these tubes will kill germs and the 184.45 nm far UV will ionize oxygen to ozone. Lamps labeled OF block the 184.45 nm far UV and do not produce significant ozone.
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Since the neutron is not charged it does not interact via the Coulomb force and therefore does not ionize the scintillation material. It must first transfer some or all of its energy via the strong force to a charged atomic nucleus. The positively charged nucleus then produces ionization. Fast neutrons (generally >0.5 MeV ) primarily rely on the recoil proton in (n,p) reactions; materials rich in hydrogen, e.g.
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Americium-241, an alpha emitter, is used in smoke detectors. The alpha particles ionize air in an open ion chamber and a small current flows through the ionized air. Smoke particles from the fire that enter the chamber reduce the current, triggering the smoke detector's alarm. Alpha decay can provide a safe power source for radioisotope thermoelectric generators used for space probes and were used for artificial heart pacemakers.
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A buffer solution contains an acid and its conjugate base or a base and its conjugate acid. Addition of the conjugate ion will result in a change of pH of the buffer solution. For example, if both sodium acetate and acetic acid are dissolved in the same solution they both dissociate and ionize to produce acetate ions. Sodium acetate is a strong electrolyte, so it dissociates completely in solution.
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Plot of ion current as function of applied voltage for a wire cylinder gaseous radiation detector. X-rays going through a gas will ionize it, producing positive ions and free electrons. An incoming photon will create a number of such ion pairs proportional to its energy. If there is an electric field in the gas chamber ions and electrons will move in different directions and thereby cause a detectable current.
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The hydrogen halides are diatomic molecules with no tendency to ionize in the gas phase (although liquified hydrogen fluoride is a polar solvent somewhat similar to water). Thus, chemists distinguish hydrogen chloride from hydrochloric acid. The former is a gas at room temperature that reacts with water to give the acid. Once the acid has formed, the diatomic molecule can be regenerated only with difficulty, but not by normal distillation.
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Upon dissolution in water, which is highly exothermic, the hydrogen halides give the corresponding acids. These acids are very strong, reflecting their tendency to ionize in aqueous solution yielding hydronium ions (H3O+). With the exception of hydrofluoric acid, the hydrogen halides are strong acids, with acid strength increasing down the group. Hydrofluoric acid is complicated because its strength depends on the concentration owing to the effects of homoconjugation.
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Mapping HI emissions with a radio telescope is a technique used for determining the structure of spiral galaxies. It is also used to map gravitational disruptions between galaxies. When two galaxies collide, the material is pulled out in strands, allowing astronomers to determine which way the galaxies are moving. HI regions effectively absorb photons that are energetic enough to ionize hydrogen, which requires an energy of 13.6 electron volts.
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Collimated stellar winds from the central star shape and shock the shell into an axially symmetric form, while producing a fast moving molecular wind. The exact point when a PPN becomes a planetary nebula (PN) is defined by the temperature of the central star. The PPN phase continues until the central star reaches a temperature of 30,000 K, after which it is hot enough to ionize the surrounding gas.
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Xenon has strong spectral lines in the UV bands, and these readily pass through the fused quartz lamp envelope. Unlike the borosilicate glass used in standard lamps, fused quartz readily passes UV radiation unless it is specially doped. The UV radiation released by a short-arc lamp can cause a secondary problem of ozone generation. The UV radiation strikes oxygen molecules in the air surrounding the lamp, causing them to ionize.
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LAESI is a relatively new technique for those samples which contain water and are relatively stable. However, it has limitations for those samples which have a lower water content. For example, this technique does not ionize dry skin, nails, tooth and bone well; this is due to low water content in these samples. Also, it needs a relatively large sampling area, compared to some other common ionization techniques.
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The radionuclide used is americium-241, which is created by bombarding plutonium with neutrons in a nuclear reactor. It decays by emitting alpha particles and gamma radiation to become neptunium-237. Smoke detectors use a very small quantity of 241Am (about 0.29 micrograms per smoke detector) in the form of americium dioxide. 241Am is used as it emits alpha particles which ionize the air in the detector's ionization chamber.
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It is left open at the other end. The end result is something like a coffee mug with a half hot dog standing on its end in the middle of the mug. When current is applied, it begins to arc at the path of least resistance, at the end near the insulator disk. This causes the gas in the area to rapidly ionize, and current begins to flow through it to the outer electrode.
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In cutting mode electrode touches the tissue, and sufficiently high power density is applied to vaporize its water content. Since water vapor is not conductive under normal circumstances, electric current cannot flow through the vapor layer. Energy delivery beyond the vaporization threshold can continue if sufficiently high voltage is applied (> +/-200 V) to ionize vapor and convert it into a conductive plasma. Vapor and fragments of the overheated tissue are ejected, forming a crater.
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It typically has a strong maximum at the minimal number of photons to ionize the system, with successive peaks (known as ATI peaks) separated by the photon energy and thus corresponding to higher numbers of photons being absorbed. In the non- perturbative regime the bound states are dressed with the electric field, shifting the ionization energy. If the ponderomotive energy of the field is greater than the photon energy \omega , then the first peak disappears.
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Radon is a colorless and odorless gas generated by the breakdown of radioactive radium, which in turn is the decay product of uranium, found in the Earth's crust. The radiation decay products ionize genetic material, causing mutations that sometimes become cancerous. Radon is the second most-common cause of lung cancer in the US, causing about 21,000 deaths each year. The risk increases 8–16% for every 100 Bq/m³ increase in the radon concentration.
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Titan has no magnetic field, although studies in 2008 showed that Titan retains remnants of Saturn's magnetic field on the brief occasions when it passes outside Saturn's magnetosphere and is directly exposed to the solar wind. This may ionize and carry away some molecules from the top of the atmosphere. Titan's internal magnetic field is negligible, and perhaps even nonexistent. Its orbital distance of 20.3 Saturn radii does place it within Saturn's magnetosphere occasionally.
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Its thermal conductivity is high. It is not easy to ionize, requiring higher voltage to start the arc. Due to higher ionization potential it produces hotter arc at higher voltage, provides wide deep bead; this is an advantage for aluminium, magnesium, and copper alloys. Other gases are often added. Blends of helium with addition of 5–10% of argon and 2–5% of carbon dioxide ("tri-mix") can be used for welding of stainless steel.
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The patent granted 6 April 2011, by the Ufficio Italiano Brevetti e Marchi . Retrieved on 10 July 2011. In March 2014 the US Patent Office replied to Rossi's US patent application with a provisional decision to reject it, saying "The specification is objected to as inoperable. Specifically there is no evidence in the corpus of nuclear science to substantiate the claim that nickel will spontaneously ionize hydrogen gas and therefore 'absorb' the resulting proton".
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When the AC period is shorter than the relaxation time to de-ionize mercury atoms in the discharge column, the discharge stays closer to optimum operating condition. Electronic ballasts convert supply frequency AC power to variable frequency AC. The conversion can reduce lamp brightness modulation at twice the power supply frequency. Low cost ballasts contain only a simple oscillator and series resonant LC circuit. This principle is called the current resonant inverter circuit.
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The nitrogen–phosphorus detector (NPD) is also known as thermionic specific detector (TSD) is a detector commonly used with gas chromatography, in which thermal energy is used to ionize an analyte. It is a type of flame thermionic detector (FTD), the other being the alkali flame-ionization detector (AFID also known as AFD). With this method, nitrogen and phosphorus can be selectively detected with a sensitivity that is 104 times greater than that for carbon.
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Titan has no magnetic field and sometimes orbits outside Saturn's magnetosphere, directly exposing it to the solar wind. This may ionize and carry away some molecules from the top of the atmosphere. Titan's atmosphere supports an opaque cloud layer that obscures Titan's surface features at visible wavelengths. The haze that can be seen in the adjacent picture contributes to the moon's anti-greenhouse effect and lowers the temperature by reflecting sunlight away from the satellite.
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The source for APCI is similar to ESI except that ions are formed by the interaction of the heated analyte solvent with a corona discharge needle set at a high electrical potential. Primary ions are formed immediately surrounding the needle, and these interact with the solvent to form secondary ions that ultimately ionize the sample. APCI is particularly useful for the analysis of nonpolar lipids such as triacylglycerols, sterols, and fatty acid esters.
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Nuclear medicine Radiation used for cancer treatment is called ionizing radiation because it forms ions in the cells of the tissues it passes through as it dislodges electrons from atoms. This can kill cells or change genes so the cells cannot grow. Other forms of radiation such as radio waves, microwaves, and light waves are called non-ionizing. They don't have as much energy so they are not able to ionize cells.
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Neutrons can make other objects, or material, radioactive. This process, called neutron activation, is the primary method used to produce radioactive sources for use in medical, academic, and industrial applications. Even comparatively low speed thermal neutrons cause neutron activation (in fact, they cause it more efficiently). Neutrons do not ionize atoms in the same way that charged particles such as protons and electrons do (by the excitation of an electron), because neutrons have no charge.
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Ionizing radiation hazard symbol X-ray photons carry enough energy to ionize atoms and disrupt molecular bonds. This makes it a type of ionizing radiation, and therefore harmful to living tissue. A very high radiation dose over a short period of time causes radiation sickness, while lower doses can give an increased risk of radiation- induced cancer. In medical imaging this increased cancer risk is generally greatly outweighed by the benefits of the examination.
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Once purified isobarically, the ion beam is then sent to the individual experiments. In order to increase the purity of the isobaric beam, laser ionization can take place inside the ionizer cavity to selectively ionize a single element chain of interest. At CERN, this device is called the Resonance Ionization Laser Ion Source (RILIS). Currently over 60% of all experiments opt to use the RILIS to increase the purity of radioactive beams.
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For atomic mass spectrometry, a sample must also be ionized. Vaporization, atomization, and ionization are often, but not always, accomplished with a single source. Alternatively, one source may be used to vaporize a sample while another is used to atomize (and possibly ionize). An example of this is laser ablation inductively-coupled plasma atomic emission spectrometry, where a laser is used to vaporize a solid sample and an inductively-coupled plasma is used to atomize the vapor.
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Uman (1986) pp. 103–110. To understand why multiple return strokes utilize the same lightning channel, one needs to understand the behavior of positive leaders, which a typical ground flash effectively becomes following the negative leader's connection with the ground. Positive leaders decay more rapidly than negative leaders do. For reasons not well understood, bidirectional leaders tend to initiate on the tips of the decayed positive leaders in which the negative end attempts to re- ionize the leader network.
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The star in the center of Fleming 1 has a temperature of and mass of 0.56 . Observations performed by European Southern Observatory showed that the central star is in fact a double degenerate (made of two white dwarfs) binary with a period of days. The companion is probably an older white dwarf of a higher mass—0.64 to 0.7 . Its temperature is about 120,000 K providing the bulk of high energy photons needed to ionize the nebula.
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LEIS systems consist of the following: General experimental setup for LEIS. # Ion Gun, used to direct a beam of ions at a target sample. An electron ionization ion source is typically used to ionize noble gas atoms such as He, Ne or Ar, while heating of wafers containing alkali atoms is used to create an alkali ion beam. The ions thus created hold a positive charge, typically +1, due to the ejection of electrons from the atoms.
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One of the following three types of ion source is used for SSIMS: electron impact ionization, surface ionization or liquid metal ion sources. In the electron impact ion source, electrons from a heated filament (cathode) are accelerated towards an anode by a voltage difference where they ionize supply gas atoms on impact. This source usually operates with noble gases. Typically the energy is variable from 0.1–5 keV allowing spot sizes from ~50 μm to several millimeters.
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The change in energy between the two energy levels must be accounted for (conservation of energy). In a neutral atom, the system will emit a photon of the difference in energy. However, if the lower state is in an inner shell, a phenomenon known as the Auger effect may take place where the energy is transferred to another bound electrons causing it to go into the continuum. This allows one to multiply ionize an atom with a single photon.
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As electrons from the cathode gain more energy, they tend to ionize, rather than excite atoms. Excited atoms quickly fall back to ground level emitting light, however, when atoms are ionized, the opposite charges are separated, and do not immediately recombine. This results in more ions and electrons, but no light. This region is sometimes called Crookes dark space, and sometimes referred to as the cathode fall, because the largest voltage drop in the tube occurs in this region.
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LET has therefore no meaning when applied to photons. However, many authors speak of "gamma LET" anyway,ICRP (International Commission on Radiation Protection) publication 103, ICRP 37 (2-4) (2007): "(116) Photons, electrons, and muons are radiations with LET values of less than 10 keV/microm." where they are actually referring to the LET of the secondary electrons, i.e., mainly Compton electrons, produced by the gamma radiation. The secondary electrons will ionize far more atoms than the primary photon.
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Ion chambers are widely used as hand held radiation survey meters to check radiation dose levels. Proportional counters use a geometry with a thin positively charged anode wire in the center of a cylindrical chamber. Most of the gas volume will act as an ionization chamber, but in the region closest to the wire the electric field is high enough to make the electrons ionize gas molecules. This will create an avalanche effect greatly increasing the output signal.
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Ion- attachment ionization is similar to chemical ionization in which a cation is attached to the analyte molecule in a reactive collision: :M + X+ + A -> MX+ + A Where M is the analyte molecule, X+ is the cation and A is a non-reacting collision partner. In a radioactive ion source, a small piece of radioactive material, for instance 63Ni or 241Am, is used to ionize a gas. This is used in ionization smoke detectors and ion mobility spectrometers.
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Use of mass spectrometry as a second component of an operando experiment allows for optical spectra to be obtained before obtaining a mass spectrum of the analytes. Electrospray ionization allows a wider range of substances to be analysed than other ionization methods, due to its ability to ionize samples without thermal degradation. In 2017, Prof. Frank Crespilho and coworks introduced a new approach to operando DEMS, aiming the enzyme activity evaluation by differential electrochemical mass spectrometry (DEMS).
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The thyratron is a special-purpose tube filled with low-pressure gas or mercury vapor. Like vacuum tubes, it contains a hot cathode and an anode, but also a control electrode which behaves somewhat like the grid of a triode. When the control electrode starts conduction, the gas ionizes, after which the control electrode can no longer stop the current; the tube "latches" into conduction. Removing anode (plate) voltage lets the gas de-ionize, restoring its non- conductive state.
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All the wavelengths in the Lyman series are in the ultraviolet band. This quantized absorption behavior occurs only up to an energy limit, known as the ionization energy. In the case of neutral atomic hydrogen, the minimum ionization energy is equal to the Lyman limit, where the photon has enough energy to completely ionize the atom, resulting in a free proton and a free electron. Above this energy (below this wavelength), all wavelengths of light may be absorbed.
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Because the majority of electrons are trapped in the Hall current, they have a long residence time inside the thruster and are able to ionize almost all of the xenon propellant, allowing mass use of 90–99%. The mass use efficiency of the thruster is thus around 90%, while the discharge current efficiency is around 70%, for a combined thruster efficiency of around 63% (= 90% × 70%). Modern Hall thrusters have achieved efficiencies as high as 75% through advanced designs.
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After very slow neutrons are generated by the reflector, producer, moderator, and so forth, they encounter a nucleus in the proportional counter and cause it to disintegrate. This nuclear reaction produces energetic charged particles that ionize gas in the proportional counter, producing an electrical signal. In the early Simpson monitors, the active component in the gas was 10B, which produced a signal via the reaction (n + 10B → α + 7Li). Recent proportional counters use the reaction (n + 3He → 3H + p) which yields 764 keV.
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This is a substantial fraction of the 7.5 μm spacing between the electrodes for minimal arc voltage. If the electron is in an electric field of 43 MV/m, it will be accelerated and acquire 21.5 eV of energy in 0.5 μm of travel in the direction of the field. The first ionization energy needed to dislodge an electron from nitrogen molecule is about 15.6 eV. The accelerated electron will acquire more than enough energy to ionize a nitrogen molecule.
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Plot of variation of ion pair current against applied voltage for a wire cylinder gaseous radiation detector. Gaseous ionization detectors are radiation detection instruments used in particle physics to detect the presence of ionizing particles, and in radiation protection applications to measure ionizing radiation. They use the ionising effect of radiation upon a gas-filled sensor. If a particle has enough energy to ionize a gas atom or molecule, the resulting electrons and ions cause a current flow which can be measured.
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These electrons will be attracted to the positive electrode, and the positive ions remaining after the photoionization will get attracted to the negatively charged electrode. These electrons and ions will establish a current through the tube. The ionization energy will be the energy of photons hνi (h is the Planck constant) that caused a steep rise in the current: Ei=hνi. When high-velocity electrons are used to ionize the atoms, they are produced by an electron gun inside a similar evacuated tube.
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The Electron beam ion trap (EBIT), based on the same principle, can produce up to bare uranium ions and can be used as an ion source as well. Heavy ions can also be generated with an Ion Gun which typically uses the thermionic emission of electrons to ionize a substance in its gaseous state. Such instruments are typically used for surface analysis.Ion beam deposition system with mass separator Gas flows through the ion source between the anode and the cathode.
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The term matrix-assisted laser desorption ionization (MALDI) was coined in 1985 by Franz Hillenkamp, Michael Karas and their colleagues. These researchers found that the amino acid alanine could be ionized more easily if it was mixed with the amino acid tryptophan and irradiated with a pulsed 266 nm laser. The tryptophan was absorbing the laser energy and helping to ionize the non-absorbing alanine. Peptides up to the 2843 Da peptide melittin could be ionized when mixed with this kind of "matrix".
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Busek patented the concept of an Air Breathing Hall Effect Thruster (ABHET) in 2004, and with funding from the NASA Institute for Advanced Concepts, started in 2011 a feasibility study that would be applied to Mars (Mars-ABHET or MABHET), where the system would breath and ionize atmospheric carbon dioxide. The MABHET concept is based on the same general principles as JAXA's ABIE or ESA's ram-EP.AEP (Air-breathing Electric Propulsion) development for future low-orbit space flight. EO Portal. ESA.
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Only the absorption of more than one neutron, a statistically rare occurrence, can activate a hydrogen atom, while oxygen requires two additional absorptions. Thus water is only very weakly capable of activation. The sodium in salt (as in sea water), on the other hand, need only absorb a single neutron to become Na-24, a very intense source of beta decay, with half-life of 15 hours. In addition, high-energy (high- speed) neutrons have the ability to directly ionize atoms.
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Materials heated beyond a few tens of thousand degrees ionize into their electrons and nuclei, producing a gas-like state of matter known as plasma. According to the ideal gas law, like any hot gas, plasma has an internal pressure and thus wants to expand. For a fusion reactor, the challenge is to keep the plasma contained; any known substance would melt or sublime at these temperatures. But because a plasma is electrically conductive, it is subject to electric and magnetic fields.
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The application of mass spectrometry to study proteins became popularized in the 1980s after the development of MALDI and ESI. These ionization techniques have played a significant role in the characterization of proteins. (MALDI) Matrix-assisted laser desorption ionization was coined in the late 80's by Franz Hillenkamp and Michael Karas. Hillenkamp, Karas and their fellow researchers were able to ionize the amino acid alanine by mixing it with the amino acid tryptophan and irradiated with a pulse 266 nm laser.
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An entrapment pump may be a cryopump, which uses cold temperatures to condense gases to a solid or adsorbed state, a chemical pump, which reacts with gases to produce a solid residue, or an ion pump, which uses strong electrical fields to ionize gases and propel the ions into a solid substrate. A cryomodule uses cryopumping. Other types are the sorption pump, non-evaporative getter pump, and titanium sublimation pump (a type of evaporative getter that can be used repeatedly).
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Artist's impression of a multi-megawatt VASIMR spacecraft The Variable Specific Impulse Magnetoplasma Rocket (VASIMR) is an electrothermal thruster under development for possible use in spacecraft propulsion. It uses radio waves to ionize and heat an inert propellant, forming a plasma, then a magnetic field to confine and accelerate the expanding plasma, generating thrust. It is a plasma propulsion engine, one of several types of spacecraft electric propulsion systems. The VASIMR method for heating plasma was originally developed during nuclear fusion research.
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The binding energy of an atom (including its electrons) is not the same as the binding energy of the atom's nucleus. The measured mass deficits of isotopes are always listed as mass deficits of the neutral atoms of that isotope, and mostly in MeV. As a consequence, the listed mass deficits are not a measure for the stability or binding energy of isolated nuclei, but for the whole atoms. This has very practical reasons, because it is very hard to totally ionize heavy elements, i.e.
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Starburst galaxies were more common during the early history of the universe, and, at present, still contribute an estimated 15% to the total star production rate. Starburst galaxies are characterized by dusty concentrations of gas and the appearance of newly formed stars, including massive stars that ionize the surrounding clouds to create H II regions. These massive stars produce supernova explosions, resulting in expanding remnants that interact powerfully with the surrounding gas. These outbursts trigger a chain reaction of star building that spreads throughout the gaseous region.
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The Dark Ages of the universe start at that point, because there were no light sources other than the gradually redshifting cosmic background radiation. The second phase change occurred once objects started to condense in the early universe that were energetic enough to re-ionize neutral hydrogen. As these objects formed and radiated energy, the universe reverted from being neutral, to once again being an ionized plasma. This occurred between 150 million and one billion years after the Big Bang (at a redshift 6 < z < 20).
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Circuit breakers with vacuum interrupters have minimal arcing characteristics (as there is nothing to ionize other than the contact material), so the arc quenches when it is stretched by a small amount (<2–8 mm). Near zero current the arc is not hot enough to maintain a plasma, and current ceases; the gap can then withstand the rise of voltage. Vacuum circuit breakers are frequently used in modern medium-voltage switchgear to 40,500 volts. Unlike the other types, they are inherently unsuitable for interrupting DC faults.
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In mass spectrometry, direct analysis in real time (DART) is an ion source that produces electronically or vibronically excited-state species from gases such as helium, argon, or nitrogen that ionize atmospheric molecules or dopant molecules. The ions generated from atmospheric or dopant molecules undergo ion-molecule reactions with the sample molecules to produce analyte ions. Analytes with low ionization energy may be ionized directly. The DART ionization process can produce positive or negative ions depending on the potential applied to the exit electrode.
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Among the types of energy released by a nuclear explosion are a large number of beta particles, or high energy electrons. These are primarily the result of beta decay within the debris from the fission portions of the bomb, which, in most designs, represents about 50% of the total yield. Because electrons are electrically charged, they induce electrical currents in surrounding atoms as they pass them at high speed. This causes the atoms to ionize while also causing the beta particles to slow down.
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The existence of multicharged positive ions is only possible in a hot dense plasma. Alternatively, the free electrons and ions may be generated temporarily and instantaneously by the intense electric field of a very-high-harmonic laser beam. The electrons accelerate as they return to the parent ion, releasing higher energy photons at diminished intensities, which may be in the EUV range. If the released photons constitute ionizing radiation, they will also ionize the atoms of the harmonic-generating medium, depleting the sources of higher-harmonic generation.
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" The current continues until the avalanche is quenched by lowering the bias voltage VD down to or below VB: the lower electric field is no longer able to accelerate carriers to impact-ionize with lattice atoms, therefore current ceases. In order to be able to detect another photon, the bias voltage must be raised again above breakdown. "This operation requires a suitable circuit, which has to: # Sense the leading edge of the avalanche current. # Generate a standard output pulse synchronous with the avalanche build-up.
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In passing through matter, charged particles ionize and thus lose energy in many steps, until their energy is (almost) zero. The distance to this point is called the range of the particle. The range depends on the type of particle, on its initial energy and on the material through which it passes. For example, if the ionising particle passing through the material is a positive ion like an alpha particle or proton, it will collide with atomic electrons in the material via Coulombic interaction.
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This is the equivalent of losing a mass equal to the Sun's every 400,000 years. The gravitational influence of the compact object appears to be reshaping this stellar wind, producing a focused wind geometry rather than a spherically symmetrical wind. X-rays from the region surrounding the compact object heat and ionize this stellar wind. As the object moves through different regions of the stellar wind during its 5.6-day orbit, the UV lines, the radio emission, and the X-rays themselves all vary.
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UV can also cause many substances to glow with visible light; this is called fluorescence. At the middle range of UV, UV rays cannot ionize but can break chemical bonds, making molecules unusually reactive. Sunburn, for example, is caused by the disruptive effects of middle range UV radiation on skin cells, which is the main cause of skin cancer. UV rays in the middle range can irreparably damage the complex DNA molecules in the cells producing thymine dimers making it a very potent mutagen.
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High-energy X-rays were applied to ionize gas particles and observe photoelectric electrons. The observation of electron tracks that were independent of the frequency of the incident photon suggested a mechanism for electron ionization that was caused from an internal conversion of energy from a radiationless transition. Further investigation, and theoretical work using elementary quantum mechanics and transition rate/transition probability calculations, showed that the effect was a radiationless effect more than an internal conversion effect."The Auger Effect and Other Radiationless Transitions".
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Either of those interactions will cause the ejection of an electron from an atom at relativistic speeds, turning that electron into a beta particle (secondary beta particle) that will ionize many other atoms. Since most of the affected atoms are ionized directly by the secondary beta particles, photons are called indirectly ionizing radiation. Photon radiation is called gamma rays if produced by a nuclear reaction, subatomic particle decay, or radioactive decay within the nucleus. It is otherwise called x-rays if produced outside the nucleus.
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This is the final stage of a low-mass star's life, like Earth's Sun. Stars with a mass up to 8–10 solar masses evolve into red giants and slowly lose their outer layers during pulsations in their atmospheres. When a star has lost enough material, its temperature increases and the ultraviolet radiation it emits can ionize the surrounding nebula that it has thrown off. Our Sun will produce a planetary nebula and its core will remain behind in the form of a white dwarf.
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There is negligible dead volume and back pressure that allows for almost real time mass spectrometry detection with a fast elution and purification. This coupling can be used to ionize a wide range of molecules, from small organics to high mass proteins. This is different from ESI (electrospray ionization) in that it can be used to directly analyze salt-containing sample solutions without requiring “make-up” solvents/ acids to be doped into the sample. This set up allows for a high flow rate without splitting.
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Some kinds of ionizing radiation can be detected in a cloud chamber. Radiation with sufficiently high energy can ionize atoms; that is to say it can knock electrons off atoms, creating ions. Ionization occurs when an electron is stripped (or "knocked out") from an electron shell of the atom, which leaves the atom with a net positive charge. Because living cells and, more importantly, the DNA in those cells can be damaged by this ionization, exposure to ionizing radiation is considered to increase the risk of cancer.
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The acidity of these zeolites was determined by infrared spectroscopic studies and comparing the vibrational frequencies of the hydroxyl groups since their Brønsted acidity comes from the hydroxyl groups attached to it. The hydroxyl groups that are more accessible exhibit more acidic properties while the oxygens in the hexagonal prism are less acidic. Copper zeolites also act as oxidizing agents as seen in their ability to ionize anthracene, the electron transfer was proven to happen at the cupric ion.Naccache, C. J. Cat 1971, 22, 171–181.
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The analytes are in the vapor phase. This includes breath, odors, VOCs, and other molecules with low volatility that, due to the constant improvements in sensitivity, are detectable in the vapor phase despite of their low vapor pressure. Analyte ions are produced via gas-phase chemical reactions, where charging agents collide with the analyte molecules and transfer their charge. In Secondary Electro-Spray Ionization (SESI), a nano-electrospray operated at high temperature produces nanodroplets that evaporate very rapidly to produce ions and protonated water clusters that ionize the vapors of interest.
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Karas and Hillenkamp were subsequently able to ionize the 67 kDa protein albumin using a nicotinic acid matrix and a 266 nm laser. Further improvements were realized through the use of a 355 nm laser and the cinnamic acid derivatives ferulic acid, caffeic acid and sinapinic acid as the matrix. The availability of small and relatively inexpensive nitrogen lasers operating at 337 nm wavelength and the first commercial instruments introduced in the early 1990s brought MALDI to an increasing number of researchers. Today, mostly organic matrices are used for MALDI mass spectrometry.
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Unlike the molecules that are part of the network itself, they are capable of moving and diffusing within the film, and can be removed using heat or a solvent. The mobile phase may play a role in plasticizing paint films, preventing them from becoming too brittle. Carboxyl groups in the polymers of the stationary phase ionize, becoming negatively charged and form complexes with metal cations present in the pigment. The original network, with its nonpolar, covalent bonds, is replaced by an ionomeric structure, held together by ionic interactions.
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Chromium has unique magnetic properties in the sense that chromium is the only elemental solid which shows antiferromagnetic ordering at room temperature (and below). Above 38 °C, its magnetic ordering changes to paramagnetic. The antiferromagnetic properties, which cause the chromium atoms to temporarily ionize and bond with themselves, are present because the body-centric cubic's magnetic properties are disproportionate to the lattice periodicity. This is due to the fact that the magnetic moments at the cube's corners and the cube centers are not equal, but are still antiparallel.
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Electrons collide with and ionize noble gas atoms inside the bulb surrounding the filament to form a plasma by the process of impact ionization. As a result of avalanche ionization, the conductivity of the ionized gas rapidly rises, allowing higher currents to flow through the lamp. The fill gas helps determine the electrical characteristics of the lamp, but does not give off light itself. The fill gas effectively increases the distance that electrons travel through the tube, which allows an electron a greater chance of interacting with a mercury atom.
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A high resolution FTICR mass spectrometer is often used for petroleomics. Ionization of nonpolar petroleum components can be achieved by field desorption ionization and atmospheric pressure photoionization (APPI). field desorption FT-ICR MS has enabled the identification of a large number of nonpolar components in crude oils that are not accessible by electrospray, such as benzo- and dibenzothiophenes, furans, cycloalkanes, and polycyclic aromatic hydrocarbons (PAHs). A drawback of field desorption is that it is slow, mainly due to the need of ramping the current to the emitter in order to volatilize and ionize molecules.
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Depending on the polarity of the high voltage electrode one distinguishes negative corona, formed around the cathode, and positive corona, formed around the anode. Negative corona is similar to the Townsend discharge, where the electrons, emitted by the cathode, accelerate in the electric field, ionize the gas in collisions with its atoms and molecules releasing more electrons, and thus creating an avalanche. Secondary processes include electron emission from the cathode and photoionization within the gas volume. Negative corona creates a uniform plasma glowing around the sharp edges of the electrodes.
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It was discovered in 2012, by a group led by L. D. Bradley, published in The Astrophysical Journal. The C IV emission line (with a wavelength of 1548 Å) was detected from this galaxy, signifying triply ionized carbon. Because it takes high amounts of energy to triply ionize carbon, it may suggest that A1703 zD6 has an active galactic nucleus (AGN), or a population of very young, hot, and metal-poor stars. Subsequent investigations found that the ionization source is likely to be the latter: a cluster of stars (abbreviated SF, for star-forming region).
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The purpose of the launch was to do measurements in the ionosphere, where charged particles from the sun ionize the atoms. The process is most intense in the polar ionosphere, and is important not only for the Northern Lights, but also for long-range radio communication, because the free electrons reflect the radio waves. The goal was to explore the possibility of improving long-range radio communication. The rocket was 7.7 m long, had a total weight of 698 kg and a maximum speed of 6760 km/h.
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They built an electron accelerator called Rheotron (invented by Max Steenbeck at Siemens-Schuckert in the 1930s, these were later called Betatrons by the Americans) to generate hard X-ray synchrotron beams for the Reichsluftfahrtministerium (RLM). The intent was to pre-ionize ignition in aircraft engines and hence serve as anti-aircraft DEW and bring planes down into the reach of the flak. The Rheotron was captured by the Americans in Burggrub on April 14, 1945. Another approach was Ernst Schiebolds 'Röntgenkanone' developed from 1943 in Großostheim near Aschaffenburg.
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A nuclear electromagnetic pulse is the abrupt pulse of electromagnetic radiation resulting from a nuclear explosion. The resulting rapidly changing electric fields and magnetic fields may couple with electrical/electronic systems to produce damaging current and voltage surges. The intense gamma radiation emitted can also ionize the surrounding air, creating a secondary EMP as the atoms of air first lose their electrons and then regain them. NEMP weapons are designed to maximize such EMP effects as the primary damage mechanism, and some are capable of destroying susceptible electronic equipment over a wide area.
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Zeus EX, later known as Spartan, was the ultimate development of the original Nike Zeus. The high-altitude explosions that had caused so much concern for Nike Zeus due to blackout had been further studied in the early 1960s and led to a new possibility for missile defense. When a nuclear warhead explodes in a dense atmosphere, its initial high-energy X-rays ionize the air, blocking other X-rays. In the highest layers of the atmosphere, there is too little gas for this to occur, and the X-rays can travel long distances.
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Neutron radiation is often called indirectly ionizing radiation. It does not ionize atoms in the same way that charged particles such as protons and electrons do (exciting an electron), because neutrons have no charge. However, neutron interactions are largely ionizing, for example when neutron absorption results in gamma emission and the gamma ray (photon) subsequently removes an electron from an atom, or a nucleus recoiling from a neutron interaction is ionized and causes more traditional subsequent ionization in other atoms. Because neutrons are uncharged, they are more penetrating than alpha radiation or beta radiation.
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In 1954, Reber moved to Tasmania, the southernmost state of Australia, where he worked with Bill Ellis at the University of Tasmania.utas.edu.au Companion to Tasmanian History: Astronomy There, on very cold, long, winter nights the ionosphere would, after many hours shielded from the sun's radiation by the bulk of the Earth, 'quieten' and de-ionize, allowing the longer radio waves into his antenna array. Reber described this as being a "fortuitous situation". Tasmania also offered low levels of man-made radio noise, which permitted reception of the faint signals from outer space.
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Individual photons can be detected by several methods. The classic photomultiplier tube exploits the photoelectric effect: a photon of sufficient energy strikes a metal plate and knocks free an electron, initiating an ever-amplifying avalanche of electrons. Semiconductor charge-coupled device chips use a similar effect: an incident photon generates a charge on a microscopic capacitor that can be detected. Other detectors such as Geiger counters use the ability of photons to ionize gas molecules contained in the device, causing a detectable change of conductivity of the gas.
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The number of plates in the arc chute is dependent on the short-circuit rating and nominal voltage of the circuit breaker. In larger ratings, oil circuit breakers rely upon vaporization of some of the oil to blast a jet of oil through the arc. Gas (usually sulfur hexafluoride) circuit breakers sometimes stretch the arc using a magnetic field, and then rely upon the dielectric strength of the sulfur hexafluoride (SF6) to quench the stretched arc. Vacuum circuit breakers have minimal arcing (as there is nothing to ionize other than the contact material).
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Electrical treeing first occurs and propagates when a dry dielectric material is subjected to high and divergent electrical field stress over a long period of time. Electrical treeing is observed to originate at points where impurities, gas voids, mechanical defects, or conducting projections cause excessive electrical field stress within small regions of the dielectric. This can ionize gases within voids inside the bulk dielectric, creating small electrical discharges between the walls of the void. An impurity or defect may even result in the partial breakdown of the solid dielectric itself.
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Conventional definition places the boundary at a photon energy between 10 eV and 33 eV in the ultraviolet (see definition boundary section below). Typical ionizing subatomic particles found in radioactive decay include alpha particles, beta particles and neutrons. Almost all products of radioactive decay are ionizing because the energy of radioactive decay is typically far higher than that required to ionize. Other subatomic ionizing particles which occur naturally are muons, mesons, positrons, and other particles that constitute the secondary cosmic particles that are produced after primary cosmic rays interact with Earth's atmosphere.
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In 1985, Hillenkamp and his colleague Michael Karas used a LAMMA 1000 mass spectrometer to demonstrate the technique of matrix-assisted laser desorption/ionization (MALDI). MALDI is an ionization method used in mass spectrometry, allowing the analysis of large biopolymers. Although Karas and Hillenkamp were the first to discover MALDI, Japanese engineer Koichi Tanaka was the first to use a similar method in 1988 to ionize proteins and shared the Nobel Prize in Chemistry in 2002 for that work. Karas and Hillenkamp reported MALDI of proteins a few months later.
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There may be dust along the line of sight from the GRB to Earth, both in the host galaxy and in the Milky Way. If so, the light will be attenuated and reddened and an afterglow spectrum may look very different from that modeled. At very high frequencies (far-ultraviolet and X-ray) interstellar hydrogen gas becomes a significant absorber. In particular, a photon with a wavelength of less than 91 nanometers is energetic enough to completely ionize neutral hydrogen and is absorbed with almost 100% probability even through relatively thin gas clouds.
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The PPN phase continues until the central star reaches around 30,000 K and it is hot enough (producing enough ultraviolet radiation) to ionize the circumstellar nebula (ejected gases) and it becomes a kind of emission nebula called a PN. This transition must take place in less than around 10,000 years or else the density of the circumstellar envelope will fall below the PN formulation density threshold of around 100 per cm³ and no PN will result, such a case is sometimes referred to as a 'lazy planetary nebula'.
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The carbon atom in cyanogen bromide is bonded to bromine by a single bond and to nitrogen by a triple bond (i.e. Br–C≡N). The compound is linear and polar, but it does not spontaneously ionize in water. It dissolves in both water and polar organic solvents. Cyanogen bromide can be prepared by oxidation of sodium cyanide with bromine, which proceeds in two steps via the intermediate cyanogen ((CN)2): :2 NaCN + Br2 → (CN)2 \+ 2 NaBr :(CN)2 \+ Br2 → 2 (CN)Br When refrigerated the material has an extended shelflife.
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One mechanism by which high energy neutrons ionize atoms is to strike the nucleus of an atom and knock the atom out of a molecule, leaving one or more electrons behind as the chemical bond is broken. This leads to production of chemical free radicals. In addition, very high energy neutrons can cause ionizing radiation by "neutron spallation" or knockout, wherein neutrons cause emission of high- energy protons from atomic nuclei (especially hydrogen nuclei) on impact. The last process imparts most of the neutron's energy to the proton, much like one billiard ball striking another.
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The highest frequencies of ultraviolet light, as well as all X-rays and gamma-rays are ionizing. The occurrence of ionization depends on the energy of the individual particles or waves, and not on their number. An intense flood of particles or waves will not cause ionization if these particles or waves do not carry enough energy to be ionizing, unless they raise the temperature of a body to a point high enough to ionize small fractions of atoms or molecules by the process of thermal-ionization (this, however, requires relatively extreme radiation intensities).
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It would use the Hall-effect, which provides low acceleration but can fire continuously for many years to thrust a large mass to high speed. Hall effect thrusters trap electrons in a magnetic field and use them to ionize the onboard xenon gas propellant. The magnetic field also generates an electric field that accelerates the charged ions creating an exhaust plume of plasma that pushes the spacecraft forward. The spacecraft concept would have a dry mass of 5.5 tons, and could store up to 13 tons of xenon propellant.
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In the context of magnetic fusion energy, cyclotron radiation losses translate into a requirement for a minimum plasma energy density in relation to the magnetic field energy density. Cyclotron radiation would likely be produced in a high altitude nuclear explosion. Gamma rays produced by the explosion would ionize atoms in the upper atmosphere and those free electrons would interact with the Earth's magnetic field to produce cyclotron radiation in the form of an electromagnetic pulse (EMP). This phenomenon is of concern to the military as the EMP may damage solid state electronic equipment.
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The gap between these energy states and the nearest energy band is usually referred to as dopant-site bonding energy or EB and is relatively small. For example, the EB for boron in silicon bulk is 0.045 eV, compared with silicon's band gap of about 1.12 eV. Because EB is so small, room temperature is hot enough to thermally ionize practically all of the dopant atoms and create free charge carriers in the conduction or valence bands. Dopants also have the important effect of shifting the energy bands relative to the Fermi level.
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For higher atomic number substances this limit is higher. The high amount of calcium (Z = 20) in bones, together with their high density, is what makes them show up so clearly on medical radiographs. A photoabsorbed photon transfers all its energy to the electron with which it interacts, thus ionizing the atom to which the electron was bound and producing a photoelectron that is likely to ionize more atoms in its path. An outer electron will fill the vacant electron position and produce either a characteristic X-ray or an Auger electron.
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When the dielectric strength of SF6 is exceeded, regions of high electrical stress can cause nearby gas to partially ionize and begin conducting, forming toxic products like SOF2 or S2F10. This method allows scientists to detect the toxic by-products of SF6 breakdown at very low concentrations (ppb) using an ion- molecule reaction cell and a negative ion mass spectrometer, as opposed to conventional methods such as electron impact mass spectrometry (MS), gas chromatography (GC) with thermal conductivity detection, gas chromatography with electron capture detection, or a combination of gas chromatography and mass spectrometry.
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Thus, vz varies as the reciprocal of the square root of the ion mass, or the arrival time is proportional to the square root of the ion mass. In a perfect experiment, the ionization laser would ionize only the products of the dissociation, and those only in a particular internal energy state. But the ionization laser, and perhaps the photolysis laser, can create ions from other material, such as pump oil or other impurities. The ability to selectively detect a single mass by gating the detector electronically is thus an important advantage in reducing noise.
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Plasma gasification is an extreme thermal process using plasma which converts organic matter into a syngas (synthesis gas) which is primarily made up of hydrogen and carbon monoxide. A plasma torch powered by an electric arc is used to ionize gas and catalyze organic matter into syngas, with slag remaining as a byproduct. It is used commercially as a form of waste treatment and has been tested for the gasification of refuse-derived fuel, biomass, industrial waste, hazardous waste, and solid hydrocarbons, such as coal, oil sands, petcoke and oil shale.
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The breakthrough for large molecule laser desorption ionization came in 1987 when Koichi Tanaka of Shimadzu Corp. and his co-workers used what they called the “ultra fine metal plus liquid matrix method” that combined 30 nm cobalt particles in glycerol with a 337 nm nitrogen laser for ionization. Using this laser and matrix combination, Tanaka was able to ionize biomolecules as large as the 34,472 Da protein carboxypeptidase-A. Tanaka received one-quarter of the 2002 Nobel Prize in Chemistry for demonstrating that, with the proper combination of laser wavelength and matrix, a protein can be ionized.
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An electrostatic fluid accelerator (EFA) is a device which pumps a fluid such as air without any moving parts. Instead of using rotating blades, as in a conventional fan, an EFA uses an electric field to propel electrically charged air molecules. Because air molecules are normally neutrally charged, the EFA has to create some charged molecules, or ions, first. Thus there are three basic steps in the fluid acceleration process: ionize air molecules, use those ions to push many more neutral molecules in a desired direction, and then recapture and neutralize the ions to eliminate any net charge.
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Astronomers hope to use observations to answer the question of how the Universe was reionised. While observations have come in which narrow the window during which the epoch of reionization could have taken place, it is still uncertain which objects provided the photons that reionized the IGM. To ionize neutral hydrogen, an energy larger than 13.6 eV is required, which corresponds to photons with a wavelength of 91.2 nm or shorter. This is in the ultraviolet part of the electromagnetic spectrum, which means that the primary candidates are all sources which produce a significant amount of energy in the ultraviolet and above.
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This method is very similar to ion milling, but in this procedure, the UHV chamber is filled with neon at a pressure of 10−4 mbar. When a negative voltage is applied on the tip, a strong electric field (produced by tip under negative potential) will ionize the neon gas, and these positively charged ions are accelerated back to the tip where they cause sputtering. The sputtering removes contaminants and some atoms from tip which, like ion milling, reduces the apex radius. By changing the field strength, one can tune the radius of the tip to 20 nm.
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The greater molecular and structural speciation is due to the pre-separation. There are many different types of instrumentation used for the analysis due to various type and combinations of the ionization, separation, and mass detection methods. Not one combination is best for all samples, and as such depending on the need for analysis, different instrumentation is used. The most commonly used ionization method for off-line instrument is electron ionization (EI) which is a hard ionization technique that utilized 70 eV to ionize the sample, which causes significant fragmentation that can be used in a library search to identify the compounds.
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Energetic cosmic rays penetrate the cold, dense clouds and ionize hydrogen and helium, resulting, for example, in the trihydrogen cation. An ionized helium atom can then split relatively abundant carbon monoxide to produce ionized carbon, which in turn can lead to organic chemical reactions. The local interstellar medium is a region of space within 100 parsecs (pc) of the Sun, which is of interest both for its proximity and for its interaction with the Solar System. This volume nearly coincides with a region of space known as the Local Bubble, which is characterized by a lack of dense, cold clouds.
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Capacitors inside the light are charged up to a relatively high voltage, roughly 300 volts for small strobes. This voltage itself is not capable of ionizing the gas in the flash tube, and the tube will not fire.Elliot Sound Products If the capacitors were charged to a voltage high enough to ionize the tube, the result would be no longer a flash, but a continuous arc as the voltage is sufficient to maintain ionization in the flash tube. Once the main storage capacitor has finished charging, a smaller capacitor is discharged into the trigger transformers primary coil.
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The inert pair effect is the tendency of the two electrons in the outermost atomic s-orbital to remain unshared in compounds of post-transition metals. The term inert pair effect is often used in relation to the increasing stability of oxidation states that are two less than the group valency for the heavier elements of groups 13, 14, 15 and 16. The term "inert pair" was first proposed by Nevil Sidgwick in 1927. The name suggests that the outermost s electrons are more tightly bound to the nucleus in these atoms, and therefore more difficult to ionize or share.
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Very hot stars of the spectral class O or B emit very energetic radiation, especially ultraviolet radiation, which is able to ionize the neutral hydrogen (H I) of the surrounding interstellar medium, so that hydrogen atoms lose their single electrons. This state of hydrogen is called H II. After a while, free electrons recombine with those hydrogen ions. Energy is re-emitted, not as a single photon, but rather as a series of photons of lesser energy. The photons lose energy as they travel outward from the star's surface, and are not energetic enough to again contribute to ionization.
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Clouds of neutral hydrogen are ubiquitous in the Milky Way galaxy, and effectively absorb photons that are energetic enough to ionize hydrogen, which requires an energy of 13.6 electron volts (in the extreme ultraviolet range). Even the relatively small amounts of hydrogen in the Lockman Hole absorb most radiation at and just above energies of 13.6 electron volts, but even so it transmits extreme ultraviolet and soft x-ray radiation from extragalactic objects to a greater degree than other areas of the sky. Neutral hydrogen is also associated with diffuse emission at infrared wavelengths that can confuse observations of faint infrared sources.
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Wax printing hydrophobic barriers is a common method for creating distinct flow channels within paper devices, and this has been extended to μPAD-MS to enhance ionization efficiency (by enabling focusing of the analyte stream) and enable reaction mixing by wax printing on the triangular paper surface. Chromatographic separations have also been demonstrated on μPADs prior to paper-spray detection. Initially, paper-spray ionization was applied for the detection of small molecules, such as pharmaceuticals and drugs of abuse. However, it has also been shown that paper-spray ionization can ionize large proteins while retaining non-covalent interactions.
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The protein’s whole mass is the sum of the masses of its amino-acid residues plus the mass of a water molecule and adjusted for any post-translational modifications. Although proteins ionize less well than the peptides derived from them, a protein in solution may be able to be subjected to ESI-MS and its mass measured to an accuracy of 1 part in 20,000 or better. This is often sufficient to confirm the termini (thus that the protein’s measured mass matches that predicted from its sequence) and infer the presence or absence of many post-translational modifications.
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For example (see the diagram), the rubber of the belt will become negatively charged while the acrylic glass of the upper roller will become positively charged. The belt carries away negative charge on its inner surface while the upper roller accumulates positive charge. Next, the strong electric field surrounding the positive upper roller (3) induces a very high electric field near the points of the nearby comb (2). At the points, the field becomes strong enough to ionize air molecules, and the electrons are attracted to the outside of the belt while positive ions go to the comb.
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In the example, the lower roller (6) is metal, which picks negative charge off the inner surface of the belt. The lower comb (7) develops a high electric field at its points that also becomes large enough to ionize air molecules. In this case, the electrons are attracted to the comb and positive air ions neutralize negative charge on the outer surface of the belt, or become attached to the belt. The exact balance of charges on the up-going versus down-going sides of the belt will depend on the combination of the materials used.
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Protoplanetary nebula known as Emperor Seiwa taken by Hubble's Advanced Camera for Surveys. During the ensuing protoplanetary nebula phase, the central star's effective temperature will continue rising as a result of the envelope's mass loss as a consequence of the hydrogen shell's burning. During this phase, the central star is still too cool to ionize the slow-moving circumstellar shell ejected during the preceding AGB phase. However, the star does appear to drive high- velocity, collimated winds which shape and shock this shell, and almost certainly entrain slow-moving AGB ejecta to produce a fast molecular wind.
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Different types of radiation have different biological effectiveness mainly because they transfer their energy to the tissue in different ways. Photons and beta particles have a low linear energy transfer (LET) coefficient, meaning that they ionize atoms in the tissue that are spaced by several hundred nanometers (several tenths of a micrometer) apart, along their path. In contrast, the much more massive alpha particles and neutrons leave a denser trail of ionized atoms in their wake, spaced about one tenth of a nanometer apart (i.e., less than one-thousandth of the typical distance between ionizations for photons and beta particles).
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In order to ensure that a proton has a chance to collide with a boron, it has to travel past a number of boron atoms. The rate of collisions is: where is the nuclear cross section between a proton and boron, is the density of boron, and is the average distance the proton travels through the boron before undergoing a fusion reaction. For p-B11, is 0.9 x 10−24 cm−2, is 2.535 g/cm3, and thus ~ 8 cm. However, travelling through the block causes the proton to ionize the boron atoms it passes, which slows the proton.
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Critical ionization velocity experiment onboard space shuttle Discovery (STS-39), releasing a plume of nitrous oxide gas. Full text Critical ionization velocity (CIV), or critical velocity (CV), is the relative velocity between a neutral gas and plasma (an ionized gas), at which the neutral gas will start to ionize. If more energy is supplied, the velocity of the atoms or molecules will not exceed the critical ionization velocity until the gas becomes almost fully ionized. The phenomenon was predicted by Swedish engineer and plasma scientist, Hannes Alfvén, in connection with his model on the origin of the Solar System (1942).
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This forms a continuum in the energy spectrum; the spectrum is continuous rather than composed of many discrete lines, which are seen at lower energies. The Lyman Series The Lyman limit is at the wavelength of 91.2 nm (912 Å), corresponding to a frequency of 3.29 million GHz and a photon energy of 13.6 eV. LyC energies are mostly in the ultraviolet C portion of the electromagnetic spectrum (see Lyman series). Although X-rays and gamma-rays will also ionize a hydrogen atom, there are far fewer of them emitted from a star's photosphere-- LyC are predominantly UV-C.
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As energy builds within the oscillating secondary circuit, the amplitude of the toroid's RF voltage rapidly increases, and the air surrounding the toroid begins to undergo dielectric breakdown, forming a corona discharge. As the secondary coil's energy (and output voltage) continue to increase, larger pulses of displacement current further ionize and heat the air at the point of initial breakdown. This forms a very electrically conductive "root" of hotter plasma, called a leader, that projects outward from the toroid. The plasma within the leader is considerably hotter than a corona discharge, and is considerably more conductive.
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Both the DPF and pinch use large electrical currents run through a gas to cause it to ionize into a plasma and then pinch down on itself to increase the density and temperature of the plasma. The DPF differs largely in form; most devices use two concentric cylinders and form the pinch at the end of the central cylinder. In contrast, z-pinch systems generally use a single cylinder, sometimes a torus, and pinch the plasma into the center. The plasma focus is similar to the high-intensity plasma gun device (HIPGD) (or just plasma gun), which ejects plasma in the form of a plasmoid, without pinching it.
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Bok globules in H II region IC 2944 Stars form in clumps of cool molecular gas that hide the nascent stars. It is only when the radiation pressure from a star drives away its 'cocoon' that it becomes visible. The hot, blue stars that are powerful enough to ionize significant amounts of hydrogen and form H II regions will do this quickly, and light up the region in which they just formed. The dense regions which contain younger or less massive still-forming stars and which have not yet blown away the material from which they are forming are often seen in silhouette against the rest of the ionised nebula.
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The vapor source is surrounded by an oil bath. By setting the temperature of the oil, the Rb vapor density can be set and kept uniform along the vapor source. AWAKE uses a laser pulse to ionize the Rb vapor. By propagating the laser pulse co-linearly within the proton bunch, the hard edge of the beam/plasma interaction seeds the self-modulation of the proton bunch, enforcing the grow over the 10m long plasma It also allows to create a phase reference for the start of the wakefield, which is needed to inject the witness bunch at the right phase for trapping and acceleration.
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The PID will only respond to components that have ionization energies similar to or lower than the energy of the photons produced by the PID lamp. As stand-alone detectors, PIDs are broad band and not selective, as these may ionize everything with an ionization energy less than or equal to the lamp photon energy. The more common commercial lamps have photons energy upper limits of approximately 8.4 eV, 10.0 eV, 10.6 eV, and 11.7 eV. The major and minor components of clean air all have ionization energies above 12.0 eV and thus do not interfere significantly in the measurement of VOCs, which typically have ionization energies below 12.0 eV.
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The primary purpose of this current is to generate a poloidal field that mixes with the one supplied by the toroidal magnets to produce the twisted field inside the plasma. The current also serves the secondary purpose of ionizing the fuel and providing some heating of the plasma before other systems take over. The main source of heating in JET is provided by two systems, positive ion neutral beam injection and ion cyclotron resonance heating. The former uses small particle accelerators to shoot fuel atoms into the plasma, where collisions cause the atoms to ionize and become trapped with the rest of the fuel.
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However, there was some criticism about his winning the prize, saying that contribution by two German scientists, Franz Hillenkamp and Michael Karas was also big enough not to be dismissed, and therefore they should also be included as prize winners. This is because they first reported in 1985 a method, with higher sensitivity using a small organic compound as a matrix, that they named matrix-assisted laser desorption/ionization (MALDI). Also Tanaka's SLD is not used currently for biomolecules analysis, meanwhile MALDI is widely used in mass spectrometry research laboratories. But while MALDI was developed prior to SLD, it was not used to ionize proteins until after Tanaka's report.
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Charged particles crossing the gas of the TPC ionize the gas atoms along their path, liberating electrons that drift towards the end plates of the detector. The characteristics of the ionization process caused by fast charged particles passing through a medium can be used for particle identification. The velocity dependence of the ionization strength is connected to the well-known Bethe- Bloch formula, which describes the average energy loss of charged particles through inelastic Coulomb collisions with the atomic electrons of the medium. Multiwire proportional counters or solid-state counters are often used as detection medium, because they provide signals with pulse heights proportional to the ionization strength.
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A video overview of how an ionization smoke detector works piezoelectric horn that produces the alarm sound. An americium container from a smoke detector An ionization smoke detector uses a radioisotope, typically americium-241, to ionize air; a difference due to smoke is detected and an alarm is generated. Ionization detectors are more sensitive to the flaming stage of fires than optical detectors, while optical detectors are more sensitive to fires in the early smouldering stage.Fleming, Jay. "Smoke Detector Technology Research" , retrieved 2011-11-07 The smoke detector has two ionization chambers, one open to the air, and a reference chamber which does not allow the entry of particles.
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One is that the injected atoms re-ionize and become charged, thereby becoming trapped inside the reactor and adding to the fuel mass. The other is that the process of being ionized occurs through impacts with the rest of the fuel, and these impacts deposit energy in that fuel, heating it. This form of heating has no inherent energy (temperature) limitation, in contrast to the ohmic method, but its rate is limited to the current in the injectors. Ion source extraction voltages are typically on the order of 50–100 kV, and high voltage, negative ion sources (-1 MV) are being developed for ITER.
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Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight, and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack the energy to ionize atoms, it can cause chemical reactions and causes many substances to glow or fluoresce.
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Thin layer chromatography (TLC) is a simple separation technique that can be coupled with DAPPI-MS to identify lipids. Some of the lipids that were seen to be separated and ionized include: cholesterol, triacylglycerols, 1,2-diol diesters, wax esters, hydrocarbons, and cholesterol esters. TLC is normally coupled with instruments in vacuum or atmospheric pressure, but vacuum pressure gives poor sensitivity for more volatile compounds and has minimal area in the vacuum chambers. DAPPI was used for its ability to ionize neutral and non-polar compounds, and was seen to be a fast and efficient method for lipid detection as it was coupled with both NP-TLC and HPTLC plates.
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Schematic of Product Imaging ApparatusIn the original product imaging paper, the positions of the ions are imaged onto a two- dimensional detector. A photolysis laser dissociates methyl iodide (CH3I), while an ionization laser is used REMPI to ionize a particular vibrational level of the CH3 product. Both lasers are pulsed, and the ionization laser is fired at a delay short enough that the products have not moved appreciably. Because ejection of an electron by the ionization laser does not change the recoil velocity of the CH3 fragment, its position at any time following the photolysis is nearly the same as it would have been as a neutral.
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Under a research grant from the NASA Lewis Research Center during the 1980s and 1990s, Martin C. Hawley and Jes Asmussen led a team of engineers in developing a Microwave Electrothermal Thruster (MET). In the discharge chamber, microwave (MW) energy flows into the center containing a high level of ions (I), causing neutral species in the gaseous propellant to ionize. Excited species flow out (FES) through the low ion region (II) to a neutral region (III) where the ions complete their recombination, replaced with the flow of neutral species (FNS) towards the center. Meanwhile, energy is lost to the chamber walls through heat conduction and convection (HCC), along with radiation (Rad).
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Photoionization detectors (PIDs) use a high-photon-energy UV lamp to ionize chemicals in the sampled gas. If the compound has an ionization energy below that of the lamp photons, an electron will be ejected, and the resulting current is proportional to the concentration of the compound. Common lamp photon energies include 10.0 eV, 10.6 eV and 11.7 eV; the standard 10.6 eV lamp lasts for years, while the 11.7 eV lamp typically last only a few months and is used only when no other option is available. A broad range of compounds can be detected at levels ranging from a few ppb to several thousand ppm.
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The D layer is the innermost layer, to above the surface of the Earth. Ionization here is due to Lyman series-alpha hydrogen radiation at a wavelength of 121.6 nanometre (nm) ionizing nitric oxide (NO). In addition, high solar activity can generate hard X-rays (wavelength ) that ionize N and O. Recombination rates are high in the D layer, so there are many more neutral air molecules than ions. Medium frequency (MF) and lower high frequency (HF) radio waves are significantly attenuated within the D layer, as the passing radio waves cause electrons to move, which then collide with the neutral molecules, giving up their energy.
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The purposes of the separation are (1) potential isobaric interference should be removed before analysis because of the high-sensitivity and low-mass resolution nature of TIMS; (2) ionization of the elements of interest maybe impeded by other elements, which results in reduced signal size and precision. The separated U, Th and Pb samples are put carefully onto a metal filament, which is usually made from Re. The elements are heated and ionize to their respective ions, which are accelerated under a strong magnetic field and are measured by a detector. The tracer solution is a solution with a known amount of U and Pb tracer isotopes. Due to elemental fractionation, both elements cannot be measured simultaneously by TIMS.
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Further increasing their effect, when silver comes in contact with fluids, it tends to ionize which increases the nanoparticles' bactericidal activity. This has been correlated to the suppression of enzymes and inhibited expression of proteins that relate to the cell's ability to produce ATP. Although it varies for every type of cell proposed, as their cell membrane composition varies greatly, It has been seen that in general, silver nanoparticles with an average size of 10 nm or less show electronic effects that greatly increase their bactericidal activity. This could also be partly due to the fact that as particle size decreases, reactivity increases due to the surface area to volume ratio increasing.
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Direct ionization corresponds to electrons ejected down-field towards the bottleneck in the Coulomb + dc electric field potential, whereas indirect ionization corresponds to electrons ejected away from the bottleneck in the Coulomb + dc electric field and only ionize upon further Coulomb interactions. The different trajectories caused by direct and indirect ionization give rise to a distinct pattern that can be detected by a two-dimensional flux detector and subsequently imaged. The images exhibited an outer ring, which corresponded to the indirect ionization process and an inner ring, which corresponded to the direct ionization process. This oscillatory pattern can be interpreted as being interferences among the trajectories of the electrons moving from the atom to the detector.
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Sunfire is a mutant with the ability to absorb solar radiation, and convert it to ionize matter into a fiery plasma state which bursts into flame when exposed to oxygen. Referring to his plasma output as "solar fire", he can release this energy through his hands as blasts of searing heat, deadly radiation, explosive concussive force, or simple flames. By ionizing the air around him, he can surround himself with an aura of heat intense enough to melt steel, or fly by focusing his aura downwards in a tight stream of ionized gas to propel him through the air like a rocket. Sunfire can see heat, by shifting his vision from visible light to infrared.
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DNA damage occurs very frequently and is generated from exposure to a variety of both exogenous and endogenous genotoxic sources. One of these include ionizing radiation, such as γ radiation and X-rays, which ionize the deoxyribose groups in the DNA backbone and can induce DSBs. Reactive oxygen species, ROS, such as superoxide (O2–), hydrogen peroxide (H2O2), hydroxyl radicals (HO•), and singlet oxygen (1O2), can also produce DSBs as a result of ionizing radiation as well as cellular metabolic processes that are naturally occurring. DSBs can also be caused by the action of DNA polymerase while attempting to replicate DNA over a nick that was introduced as a result of DNA damage.
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A major difficulty in using this method in practice is that the energetic electron released by the decay of one atom of tritium can break apart, modify, ionize, or excite hundreds of other molecules in its path. These fragments and ions can further react with the surrounding molecules producing more products. Without special precautions, it would be impossible to distinguish these "radiolytic" products and reactions from the "nucleogenic" ones due to mutation and reactions of the cation . The technique developed by Cacace and his team to overcome this problem is to use a starting compound that has at least two tritium atoms substituted for hydrogens, and dilute it in a large amount of an unsubstituted compound.
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Fairey Aviation won the contract to develop Blue Sky, which they referred to internally as Project 5. Like the original Little Ben, Project 5 called for a beam riding missile able to be launched from the rear aspect within a 15° cone. Wartime German research suggested that the rocket exhaust would ionize the air behind the missile and make it difficult to receive the radar signal, so Fairey based their design on the original Red Hawk layout using separate boosters that fell away during flight, leaving the signal clear while the unpowered "dart" continued on to the target. In place of the original four RP-3 rockets, two custom-designed "Stork" rockets were used.
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Each subsystem is housed in a separate transit case with protective covers. The purpose of the Thor III dismounted system is to provide the user in the field with a wearable Radio-Controlled Improvised Explosive Device (RCIED) jammer that has been designed to counter an array of frequency diverse threats. The system is an expandable, active and reactive, scanning-receiver-based jammer with multiple jamming signal sources that allow it to counter multiple simultaneous threats. Joint IED Neutralizer (JIN): In 2005, Ionatron attempted to develop an anti IED device that would "zap" IEDs from a distance by using lasers to ionize the air and allow man-made lightning to shoot towards the devices detonating them at a safe distance.
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This domain consists of molecular regions that make hydrophobic interactions with the FKB domain and triene region from C-1-C-6, methoxy group at C-7, and methyl groups at C-33, C-27 and C-25. All changes of the macrolide ring can have unpredictible effects on binding and therefore, make determination of SAR for rapalogs problematic. Rapamycin contains no functional groups that ionize in the pH range 1-10 and therefore, are rather insoluble in water. Despite its effectiveness in preclinic cancer models, its poor solubility in water, stability, and the long half-life elimination made its parenteral use difficult, but the development of soluble rapamycin analogs vanquished various barriers.
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In the original 1929 formulation by Mott and Heisenberg, the spherical wave function of an alpha ray emitted from the decay of a radioactive atomic nucleus was considered. It was noted that the result of such a decay is always observed as linear tracks seen in Wilson's cloud chamber. Intuitively, one might think that such a wave function should randomly ionize atoms throughout the cloud chamber, but this is not the case. Mott demonstrated that by considering the interaction in configuration space, where all of the atoms of the cloud chamber play a role, it is overwhelmingly probable that all of the condensed droplets in the cloud chamber will lie close to the same straight line.
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The secondary electrons produced during the process of ionization by the primary charged particle are conventionally called delta rays, if their energy is large enough so that they themselves can ionize."Delta ray" in Encyclopedia britannica online, retrieved 22 Dec. 2012 Many studies focus upon the energy transferred in the vicinity of the primary particle track and therefore exclude interactions that produce delta rays with energies larger than a certain value Δ. This energy limit is meant to exclude secondary electrons that carry energy far from the primary particle track, since a larger energy implies a larger range. This approximation neglects the directional distribution of secondary radiation and the non-linear path of delta rays, but simplifies analytic evaluation.
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Strobe lights usually use flashtubes with energy supplied from a capacitor, an energy storage device much like a battery, but capable of charging and releasing energy much faster. In a capacitor-based strobe, the capacitor is charged up to around 300 V. Once the capacitor has been charged, to trigger the flash a small amount of power is diverted into a trigger transformer, a small transformer with a high turns ratio. This generates the weak but high-voltage spike required to ionize the xenon gas in a flash tube. An arc is created inside the tube, which acts as a path for the capacitor to discharge through, allowing the capacitor to quickly release its energy into the arc.
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Schematic of the thermospray probe and ion source used in EPA Method 8321B which utilized High Performance Liquid Chromatography-Thermospray-Mass Spectrometry (HPLC-TS-MS).As a direct sampling technique, thermospray is able to gently ionize various types of analytes such that the resulting spectrum shows few fragments of the molecular ion and accompanying buffer gas components. This lack of fragmentation typically hinders the acquisition of structural information, however thermospray is still capable of quantitative results and is valued for its range of viable analytes. When thermospray is coupled with High performance liquid chromatography mass spectrometry (TSP- HPLC-MS) the result is a highly sensitive method that is capable of lower detection limits than other HPLC-MS methods.
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Neutrinos as such cannot be detected directly, because they do not ionize the materials they are passing through (they do not carry electric charge and other proposed effects, like the MSW effect, do not produce traceable radiation). A unique reaction to identify antineutrinos, sometimes referred to as inverse beta decay, as applied by Reines and Cowan (see below), requires a very large detector to detect a significant number of neutrinos. All detection methods require the neutrinos to carry a minimum threshold energy. So far, there is no detection method for low-energy neutrinos, in the sense that potential neutrino interactions (for example by the MSW effect) cannot be uniquely distinguished from other causes.
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In operation, some of the electrons are forced to leave the atoms of the gas near the anode by the electric field applied between the two electrodes, leaving these atoms positively ionized. The free electrons thus released flow onto the anode, while the cations thus formed are accelerated by the electric field and flow towards the cathode. Typically, after traveling a very short distance, the ions collide with neutral gas atoms, which transfer their electrons to the ions. The atoms which lost an electron during the collisions ionize and speed toward the cathode while the ions which gained an electron during the collisions return to a lower energy state while releasing energy in the form of photons.
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A super star cluster (SSC) is a very massive young open cluster that is thought to be the precursor of a globular cluster. These clusters are referred to as "super" due to the fact that they are relatively more luminous and contain more mass than other young star clusters. The SSC, however, does not have to physically be larger than other clusters of lower mass and luminosity. They typically contain a very large number of young, massive stars that ionize a surrounding HII region or a so-called "Ultra dense HII regions (UDHIIs)" in the Milky Way Galaxy as well as in other galaxies (however, SSCs do not always have to be inside an HII region).
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The main pathway for the production of is by the reaction of and H2. : + H2 → + H The concentration of is what limits the rate of this reaction in nature: the only known natural source of it is via ionization of H2 by a cosmic ray in interstellar space by the ionization of H2: :H2 \+ cosmic ray → + e− \+ cosmic ray The cosmic ray has so much energy, it is almost unaffected by the relatively small energy transferred to the hydrogen when ionizing an H2 molecule. In interstellar clouds, cosmic rays leave behind a trail of , and therefore . In laboratories, is produced by the same mechanism in plasma discharge cells, with the discharge potential providing the energy to ionize the H2.
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A lightning arrester may be a spark gap or may have a block of a semiconducting material such as silicon carbide or zinc oxide. "Thyrite" was the trade name used by General Electric for the silicon carbide composite used in their arrester and varistor products. Some spark gaps are open to the air, but most modern varieties are filled with a precision gas mixture, and have a small amount of radioactive material to encourage the gas to ionize when the voltage across the gap reaches a specified level. Other designs of lightning arresters use a glow-discharge tube (essentially like a neon glow lamp) connected between the protected conductor and ground, or voltage-activated solid-state switches called varistors or MOVs.
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The induction acceleration method, integrating modern pulse power technology and state-of-art digital control, is crucial for the rapid-cycle KEK-DA. The key issues of beam dynamics associated with low- energy injection of heavy ions are beam loss caused by electron capture and stripping as results of the interaction with residual gas molecules and the closed orbit distortion resulting from relatively high remanent fields in the bending magnets. Disturbing as it may sound, imagine cancer cells located near a human organ, cells that need to be treated. One of the most promising treatments is to irradiate cancer cells with high energy particles in order to ionize the DNA molecules in the cancer cells, breaking the molecules and killing the cells.
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Different types of 400x400px Non-ionizing (or non-ionising) radiation refers to any type of electromagnetic radiation that does not carry enough energy per quantum (photon energy) to ionize atoms or molecules—that is, to completely remove an electron from an atom or molecule. Instead of producing charged ions when passing through matter, non-ionizing electromagnetic radiation has sufficient energy only for excitation, the movement of an electron to a higher energy state. In contrast, ionizing radiation has a higher frequency and shorter wavelength than non-ionizing radiation, and can be a serious health hazard; exposure to it can cause burns, radiation sickness, cancer, and genetic damage. Using ionizing radiation requires elaborate radiological protection measures, which in general are not required with non-ionizing radiation.
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The fact that trace concentrations of gases in contact with an electrospray plume were efficiently ionized was first observed by Fenn and colleagues when they noted that tiny concentrations of plasticizers produced intense peaks in their mass spectra. However, it was not until 2000 when this problem was reframed as a solution, when Hill and coworkers used an electrospray to ionize molecules in the gas phase, and named the technique Secondary Electrospray Ionization. In 2007, the almost simultaneous works of Zenobi and Pablo Sinues applied SESI to breath analysis for the first time, marking the beginning of a fruitful field or research. With sensitivities in the low pptv range (10−12), SESI has been used in other applications, where the detection of low volatility vapors is important.
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The difference in the chemical properties between different molecules in a mixture and their relative affinity for the stationary phase of the column will promote separation of the molecules as the sample travels the length of the column. The molecules are retained by the column and then elute (come off) from the column at different times (called the retention time), and this allows the mass spectrometer downstream to capture, ionize, accelerate, deflect, and detect the ionized molecules separately. The mass spectrometer does this by breaking each molecule into ionized fragments and detecting these fragments using their mass-to-charge ratio. GC-MS schematic These two components, used together, allow a much finer degree of substance identification than either unit used separately.
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This property of causing molecular damage that is out of proportion to heating effects, is characteristic of all EMR with frequencies at the visible light range and above. These properties of high-frequency EMR are due to quantum effects that permanently damage materials and tissues at the molecular level. At the higher end of the ultraviolet range, the energy of photons becomes large enough to impart enough energy to electrons to cause them to be liberated from the atom, in a process called photoionisation. The energy required for this is always larger than about 10 electron volt (eV) corresponding with wavelengths smaller than 124 nm (some sources suggest a more realistic cutoff of 33 eV, which is the energy required to ionize water).
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A high voltage is applied to the specimen, and either a laser pulse is applied to the specimen or a voltage pulse (typically 1-2 kV) with pulse repetition rates in the hundreds of kilohertz range is applied to a counter electrode. The application of the pulse to the sample allows for individual atoms at the sample surface to be ejected as an ion from the sample surface at a known time. Typically the pulse amplitude and the high voltage on the specimen are computer controlled to encourage only one atom to ionize at a time, but multiple ionizations are possible. The delay between application of the pulse and detection of the ion(s) at the detector allow for the computation of a mass-to-charge ratio.
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X-rays are electromagnetic waves with a wavelength less than about 10−9 m (greater than 3x1017 Hz and 1,240 eV). A smaller wavelength corresponds to a higher energy according to the equation E=h c/λ. ("E" is Energy; "h" is Planck's constant; "c" is the speed of light; "λ" is wavelength.) When an X-ray photon collides with an atom, the atom may absorb the energy of the photon and boost an electron to a higher orbital level or if the photon is extremely energetic, it may knock an electron from the atom altogether, causing the atom to ionize. Generally, larger atoms are more likely to absorb an X-ray photon since they have greater energy differences between orbital electrons.
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When ionizing radiation strikes the tube, some molecules of the fill gas are ionized directly by the incident radiation, and if the tube cathode is an electrical conductor, such as stainless steel, indirectly by means of secondary electrons produced in the walls of the tube, which migrate into the gas. This creates positively charged ions and free electrons, known as ion pairs, in the gas. The strong electric field created by the voltage across the tube's electrodes accelerates the positive ions towards the cathode and the electrons towards the anode. Close to the anode in the "avalanche region" where the electric field strength rises exponentially as the anode is approached, free electrons gain sufficient energy to ionize additional gas molecules by collision and create a large number of electron avalanches.
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To ionize neutral hydrogen, an energy larger than 13.6 eV is required, which corresponds to ultraviolet photons with a wavelength of 91.2 nm or shorter, implying that the sources must have produced significant amount of ultraviolet and higher energy. Protons and electrons will recombine if energy is not continuously provided to keep them apart, which also sets limits on how numerous the sources were and their longevity. With these constraints, it is expected that quasars and first generation stars and galaxies were the main sources of energy. The current leading candidates from most to least significant are currently believed to be Population III stars (the earliest stars) (possibly 70%), dwarf galaxies (very early small high-energy galaxies) (possibly 30%), and a contribution from quasars (a class of active galactic nuclei).
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The rock which has not floated off in the flotation cell is either discarded as tailings or further processed to extract other metals such as lead (from galena) and zinc (from sphalerite), should they exist. To improve the process efficiency, lime is used to raise the pH of the water bath, causing the collector to ionize more and to preferentially bond to chalcopyrite (CuFeS2) and avoid the pyrite (FeS2). Iron exists in both primary zone minerals. Copper ores containing chalcopyrite can be concentrated to produce a concentrate with between 20% and 30% copper-in-concentrate (usually 27–29% copper); the remainder of the concentrate is iron and sulfur in the chalcopyrite, and unwanted impurities such as silicate gangue minerals or other sulfide minerals, typically minor amounts of pyrite, sphalerite or galena.
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Young, massive and hot stars (typically of spectral types O and B) in H II regions emit UV photons that ionize ground-state hydrogen atoms, knocking electrons and protons free; this process is known as photoionization. The free electrons can strike other atoms nearby, exciting bound metallic electrons into a metastable state, which eventually decay back into a ground state, emitting photons with energies that correspond to forbidden lines. Through these transitions, astronomers have developed several observational methods to estimate metal abundances in HII regions, where the stronger the forbidden lines in spectroscopic observations, the higher the metallicity. These methods are dependent on one or more of the following: the variety of asymmetrical densities inside HII regions, the varied temperatures of the embedded stars, and/or the electron density within the ionized region.
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Secondary ion mass spectrometry (SIMS) is a method very similar to FAB in that a beam of particles is fired against the surface of a sample in order to cause sputtering, in which the molecules of the sample ionize and leave the surface, thus allowing for the ions or the sample to be analyzed. The primary difference is that in SIMS, an ion beam is fired against the surface, but in FAB, an atom beam is fired against the surface. The other primary difference, of more interest to this page, is that, unlike FAB, SIMS is typically performed on a solid sample with little sample preparation required. The main consideration with SIMS is ensuring that the sample is stable under ultra-high vacuum, or pressures less than 10−8 torr.
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"Acid rain" is a popular term referring to the deposition of a mixture from wet (rain, snow, sleet, fog, cloudwater, and dew) and dry (acidifying particles and gases) acidic components. Distilled water, once carbon dioxide is removed, has a neutral pH of 7. Liquids with a pH less than 7 are acidic, and those with a pH greater than 7 are alkaline. "Clean" or unpolluted rain has an acidic pH, but usually no lower than 5.7, because carbon dioxide and water in the air react together to form carbonic acid, a weak acid according to the following reaction: : (l) + (g) (aq) Carbonic acid then can ionize in water forming low concentrations of carbonate and hydronium ions: : (l) + (aq) − (aq) + + (aq) Unpolluted rain can also contain other chemicals which affect its pH (acidity level).
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The physical mechanism causing breakdown differs in different substances. In a solid, it usually occurs when the electric field becomes strong enough to pull outer valence electrons away from their atoms, so they become mobile, and the heat created by their collisions releases additional electrons. In a gas, the electric field accelerates the small number of free electrons naturally present (due to processes like photoionization) to a high enough speed that when they collide with gas molecules they knock additional electrons out of them, called ionization, which go on to ionize more molecules creating more free electrons and ions in a chain reaction called a Townsend discharge. As illustrated above, in most materials breakdown occurs by a chain reaction in which mobile charge particles release additional charged particles.
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Ice cores containing thin nitrate-rich layers have been analysed to try to reconstruct a history of past solar storms predating reliable observations. This was based on the hypothesis that solar energetic particles would ionize nitrogen, leading to the production of NO and other oxidised nitrogen compounds, which would not be too diluted in the atmosphere before being deposited along with snow. Beginning in 1986, some researchers claimed that data from Greenland ice cores showed evidence of individual solar-proton events, including the Carrington event. More ice core work casts significant doubt on this interpretation, and shows that nitrate spikes are likely not a result of solar energetic particle events but can be due to terrestrial events such as forest fires, and also correlate with other chemical signatures of known forest fire plumes.
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Combined optical and infrared image of VY CMa. The bright star at the upper right is τ Canis Majoris. (ESO/Digitized Sky Survey 2) VLBA used to derive VY CMa's 2011 distance estimate In 1976, Charles J. Lada and Mark J. Reid published observations of the bright-rimmed molecular cloud Sh2-310, which is 15' east of VY Canis Majoris. At the edge of the cloud bordered by the bright rim, an abrupt decrease in the CO emission and an increase in brightness of the emission were observed, indicating possible destruction of molecular material and enhanced heating at the cloud-rim interface, respectively. Lada and Reid assumed the distance of Sh2-310 is approximately equal to that of the stars, which are members of the open cluster NGC 2362, that ionize the rim.
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The total prompt gamma ray energy in a fission explosion is 3.5% of the yield, but in a 10 kiloton detonation the triggering explosive around the bomb core absorbs about 85% of the prompt gamma rays, so the output is only about 0.5% of the yield. In the thermonuclear Starfish Prime the fission yield was less than 100% and the thicker outer casing absorbed about 95% of the prompt gamma rays from the pusher around the fusion stage. Thermonuclear weapons are also less efficient at producing EMP because the first stage can pre-ionize the air which becomes conductive and hence rapidly shorts out the Compton currents generated by the fusion stage. Hence, small pure fission weapons with thin cases are far more efficient at causing EMP than most megaton bombs.
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At sufficiently high flux levels, various bands of electromagnetic radiation have been found to cause deleterious health effects in people. Electromagnetic radiation can be classified into two types: ionizing radiation and non- ionizing radiation, based on the capability of a single photon with more than 10 eV energy to ionize atoms or break chemical bonds. Extreme ultraviolet and higher frequencies, such as X-rays or gamma rays are ionizing, and these pose their own special hazards: see radiation and radiation poisoning. The last quarter of the twentieth century saw a dramatic increase in the number of devices emitting non-ionizing radiation in all segments of society, which resulted in an elevation of health concerns by researchers and clinicians, and an associated interest in government regulation for safety purposes.
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A mendelevium atom has 101 electrons, of which at least three (and perhaps four) can act as valence electrons. They are expected to be arranged in the configuration [Rn]5f137s2 (ground state term symbol 2F7/2), although experimental verification of this electron configuration had not yet been made as of 2006.Silva, pp. 1633–4 In forming compounds, three valence electrons may be lost, leaving behind a [Rn]5f12 core: this conforms to the trend set by the other actinides with their [Rn] 5fn electron configurations in the tripositive state. The first ionization potential of mendelevium was measured to be at most (6.58 ± 0.07) eV in 1974, based on the assumption that the 7s electrons would ionize before the 5f ones; this value has since not yet been refined further due to mendelevium's scarcity and high radioactivity.
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The incorporation of polar functional groups, such as the alcohol, amine, amide, carboxylic acid, sulfonic acid and phosphate groups, which either ionize or are capable of relatively strong intermolecular forces of attraction with water (hydrogen bonding), will usually result in analogues with an increased water solubility. Acidic and basic groups are particularly useful, since these groups can be used to form salts, which would give a wider range of dosage forms for the final product. However, the formation of zwitterions by the introduction of either an acid group into a structure containing a base or a base group into a structure containing an acid group can reduce water solubility. Introduction of weakly polar groups, such as carboxylic acid esters, aryl halides and alkyl halides, will not significantly improve water solubility and can result in enhanced lipid solubility.
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Burgot has argued that H3O+(aq) + H2O (l) ⇄ H2O (aq) + H3O+ (aq) is simply not a thermodynamically well-defined process. For an estimate of pKaaq(H3O+), Burgot suggests taking the measured value pKaEtOH(H3O+) = 0.3, the pKa of H3O+ in ethanol, and applying the correlation equation pKaaq = pKaEtOH – 1.0 (± 0.3) to convert the ethanol pKa to an aqueous value, to give a value of pKaaq(H3O+) = –0.7 (± 0.3). It is the most acidic species that can exist in water (assuming sufficient water for dissolution): any stronger acid will ionize and protonate a water molecule to form hydronium. The acidity of hydronium is the implicit standard used to judge the strength of an acid in water: strong acids must be better proton donors than hydronium, otherwise a significant portion of acid will exist in a non-ionized state (i.e.
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Getter in opened tube; silvery deposit from getter Dead vacuum fluorescent display (air has leaked in and the getter spot has become white) A vacuum tube needs an extremely good ("hard") vacuum to avoid the consequences of generating positive ions within the tube. With a small amount of residual gas, some of those atoms may ionize when struck by an electron and create fields that adversely affect the tube characteristics. Larger amounts of residual gas can create a self-sustaining visible glow discharge between the tube elements. To avoid these effects, the residual pressure within the tube must be low enough that the mean free path of an electron is much longer than the size of the tube (so an electron is unlikely to strike a residual atom and very few ionized atoms will be present).
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2 kW Hall thruster in operation as part of the Hall Thruster Experiment at the Princeton Plasma Physics Laboratory In spacecraft propulsion, a Hall-effect thruster (HET) is a type of ion thruster in which the propellant is accelerated by an electric field. Hall-effect thrusters use a magnetic field to limit the electrons' axial motion and then use them to ionize propellant, efficiently accelerate the ions to produce thrust, and neutralize the ions in the plume. Hall-effect thrusters (based on the discovery by Edwin Hall) are sometimes referred to as Hall thrusters or Hall-current thrusters. The Hall- effect thruster is classed as a moderate specific impulse (1,600s) space propulsion technology and has benefited from considerable theoretical and experimental research since the 1960s. 6 kW Hall thruster in operation at the NASA Jet Propulsion Laboratory.
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The components of the gas mixture are vital to the operation and application of a G-M tube. The mixture is composed of an inert gas such as helium, argon or neon which is ionised by incident radiation, and a "quench" gas of 5–10% of an organic vapor or a halogen gas to prevent spurious pulsing by quenching the electron avalanches. This combination of gases is known as a Penning mixture and makes use of the Penning ionization effect. The modern halogen-filled G–M tube was invented by Sidney H. Liebson in 1947 and has several advantages over the older tubes with organic mixtures. The halogen tube discharge takes advantage of a metastable state of the inert gas atom to more-readily ionize a halogen molecule than an organic vapor, enabling the tube to operate at much lower voltages, typically 400–600 volts instead of 900–1200 volts.
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As the gases expand, the central star undergoes a two-stage evolution, first growing hotter as it continues to contract and hydrogen fusion reactions occur in the shell around the core and then slowly cooling when the hydrogen shell is exhausted through fusion and mass loss. In the second phase, it radiates away its energy and fusion reactions cease, as the central star is not heavy enough to generate the core temperatures required for carbon and oxygen to fuse. During the first phase, the central star maintains constant luminosity, while at the same time it grows ever hotter, eventually reaching temperatures around 100,000 K. In the second phase, it cools so much that it does not give off enough ultraviolet radiation to ionize the increasingly distant gas cloud. The star becomes a white dwarf, and the expanding gas cloud becomes invisible to us, ending the planetary nebula phase of evolution.
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Storage vessels made of silica are used for less-demanding applications and vessels of ultrapure tin are used for the highest-purity applications. It is worth noting that, although electrical conductivity only indicates the presence of ions, the majority of common contaminants found naturally in water ionize to some degree. This ionization is a good measure of the efficacy of a filtration system, and more expensive systems incorporate conductivity-based alarms to indicate when filters should be refreshed or replaced. For comparison,Conductivity sea water has a conductivity of perhaps 5 S/m (53 mS/cm is quoted), while normal un-purified tap water may have conductivity of 5 mS/m (50 μS/cm) (to within an order of magnitude), which is still about 2 or 3 orders of magnitude higher than the output from a well- functioning demineralizing or distillation mechanism, so low levels of contamination or declining performance are easily detected.
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Both of these decay modes rearrange the nucleons without transmuting the technetium into another element. Tc-99m decays mainly by gamma emission, slightly less than 88% of the time. (99mTc → 99Tc + γ) About 98.6% of these gamma decays result in 140.5 keV gamma rays and the remaining 1.4% are to gammas of a slightly higher energy at 142.6 keV. These are the radiations that are picked up by a gamma camera when 99mTc is used as a radioactive tracer for medical imaging. The remaining approximately 12% of 99mTc decays are by means of internal conversion, resulting in ejection of high speed internal conversion electrons in several sharp peaks (as is typical of electrons from this type of decay) also at about 140 keV (99mTc → 99Tc+ \+ e−). These conversion electrons will ionize the surrounding matter like beta radiation electrons would do, contributing along with the 140.5 keV and 142.6 keV gammas to the total deposited dose.
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See also a news article on this. Brian Naranjo, a graduate student working under Putterman, conducted the experiment demonstrating the use of a pyroelectric power source for producing fusion on a laboratory bench top device.Brian Naranjo, "Observation of Nuclear Fusion Driven by a Pyroelectric Crystal", A dissertation submitted in partial satisfaction of the requirements for the degree Doctor of Philosophy in Physics, University of California, Los Angeles, 2006, 57 pages, Dr. Seth Putterman, Committee Chair. No reference to the earlier experimental work of Jabon, Fedorovich and Samsonenko [2] is found in Dr. Naranjo's dissertation. The device used a lithium tantalate () pyroelectric crystal to ionize deuterium atoms and to accelerate the deuterons towards a stationary erbium dideuteride (D2) target. Around 1000 fusion reactions per second took place, each resulting in the production of an 820 keV helium-3 nucleus and a 2.45 MeV neutron. The team anticipates applications of the device as a neutron generator or possibly in microthrusters for space propulsion.
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