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Wang, Xiaoping, Shusai Zheng, Zhen Li, Shaoming Pan, Weibo Fan, Daomin Min und Shengtao Li. „Radiation electron trajectory modulated DC surface flashover of polyimide in vacuum“. Journal of Physics D: Applied Physics 55, Nr. 20 (17.02.2022): 205201. http://dx.doi.org/10.1088/1361-6463/ac4cf8.
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Abstract Improving surface flashover voltage on vacuum-dielectric interface irradiated by electrons is a long-standing challenge for developing high-voltage and high-power spacecraft technology. The basic issue is understanding the role of radiation electrons in the process of surface flashover. In this paper, a ‘three-segment’ curve concerning the surface flashover properties under electron irradiation is discovered experimentally. As the gap distance of electrodes increase, the surface flashover voltage of polyimide during electron irradiation presents a trend of firstly increasing, then decreasing, and finally stabilizing. According to the simulation of the trajectory distribution for kinetic electrons, this trend is found to correspond with three typical stages respectively. In stage A, the kinetic electrons are completely deflected and the varying electrode parameters mainly affect the electric field distribution. In stage B, the kinetic electrons can irradiate the part of polyimide. The promoting effect of those electrons on flashover process enhance with the enlargement of the irradiated region. In stage C, trajectories are no longer seriously deflected and the role of kinetic electrons do not vary with electrode parameters. Combining with the results above, a model with combined effects of both kinetic and deposited electrons on surface flashover in vacuum is thus proposed, base on which the guidance for the methods of improving surface flashover voltage during electron irradiation is provided.
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Nur-E-Habiba, Rokon Uddin, Kalle Salminen, Veikko Sariola und Sakari Kulmala. „Carbon Particle-Doped Polymer Layers on Metals as Chemically and Mechanically Resistant Composite Electrodes for Hot Electron Electrochemistry“. Journal of Electrochemical Science and Technology 13, Nr. 1 (28.02.2022): 100–111. http://dx.doi.org/10.33961/jecst.2021.00640.
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This paper presents a simple and inexpensive method to fabricate chemically and mechanically resistant hot electron-emitting composite electrodes on reusable substrates. In this study, the hot electron emitting composite electrodes were manufactured by doping a polymer, nylon 6,6, with few different brands of carbon particles (graphite, carbon black) and by coating metal substrates with the aforementioned composite ink layers with different carbon-polymer mass fractions. The optimal mass fractions in these composite layers allowed to fabricate composite electrodes that can inject hot electrons into aqueous electrolyte solutions and clearly generate hot electron-induced electrochemiluminescence (HECL). An aromatic terbium (III) chelate was used as a probe that is known not to be excited on the basis of traditional electrochemistry but to be efficiently electrically excited in the presence of hydrated electrons and during injection of hot electrons into aqueous solution. Thus, the presence of hot, pre-hydrated or hydrated electrons at the close vicinity of the composite electrode surface were monitored by HECL. The study shows that the extreme pH conditions could not damage the present composite electrodes. These low-cost, simplified and robust composite electrodes thus demonstrate that they can be used in HECL bioaffinity assays and other applications of hot electron electrochemistry.
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Kumar, Amit, Krishna Katuri, Piet Lens und Dónal Leech. „Does bioelectrochemical cell configuration and anode potential affect biofilm response?“ Biochemical Society Transactions 40, Nr. 6 (21.11.2012): 1308–14. http://dx.doi.org/10.1042/bst20120130.
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Electrochemical gradients are the backbone of basic cellular functions, including chemo-osmotic transport and ATP synthesis. Microbial growth, terminal respiratory proteins and external electron transfer are major pathways competing for electrons. In BESs (bioelectrochemical systems), such as MFCs (microbial fuel cells), the electron flow can be via soluble inorganic/organic molecules or to a solid surface. The flow of electrons towards a solid surface can be via outer-membrane cytochromes or electron-shuttle molecules, mediated by conductive protein nanowires or extracellular matrices. In MECs (microbial electrolysis cells), the anode potential can vary over a wide range, which alters the thermodynamic energy available for bacteria capable of donating electrons to the electrode [termed EAB (electroactive bacteria)]. Thus the anode potential is an important electrochemical parameter determining the growth, electron distribution/transfer and electrical activity of films of these bacteria on electrodes. Different optimal applied potentials to anodes have been suggested in the literature, for selection for microbial growth, diversity and performance in biofilms on electrodes. In the present paper, we review the effects of anode potentials on electron-transfer properties of such biofilms, and report on the effect that electrochemical cell configuration may have on performance.
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ZHANG, C. „EFFECT OF INELASTIC SCATTERING OF HOT ELECTRONS ON THERMIONIC COOLING IN A SINGLE-BARRIER STRUCTURE“. International Journal of Modern Physics B 14, Nr. 14 (10.06.2000): 1451–57. http://dx.doi.org/10.1142/s0217979200001503.
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One of the important problems in thermionics using layered structures is the inelastic scattering of hot electrons in the electrodes and in the barrier region. Scattering in these systems is mainly via the electron–phonon interaction, or indirectly via the electron–electron interaction. In semiconductor heterostructures at room temperature, the LO-phonon plays a crucial role in thermalising electrons. In this work we study the effect of electron–phonon scattering on thermionic cooling in a single-barrier structure. Because of the asymmetry of the barrier under a bias, a larger fraction of the total energy loss will be dissipated in the hot electrode. As a result, we find that the theoretical thermal efficiency can increase due to limited electron–phonon scattering.
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Joens, Steve. „Hitachi S-4700 ExB Filter Design and Applications“. Microscopy and Microanalysis 7, S2 (August 2001): 878–79. http://dx.doi.org/10.1017/s1431927600030464.
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Electron beam - specimen interactions and SEM signals have been well understood and documented for many years. These interactions result in a variety of electron signals including the most common, secondary and backscattered electron. Each electron signal produces unique characteristic information about the sample surface, subsurface, and elemental composition. Important information can be gained by controlling and filtering electron signals collected by the electron detector system.The S-4700 Cold Field Emission SEM incorporates a set of electrodes and plates positioned in the objective lens upper pole piece in close proximity to the upper secondary detector (figure 1). When a positive voltage is applied to the electrode plates, a high yield of secondary and backscattered electrons spiral up the column of the objective lens. The backscattered electrons are filtered with the ExB producing a SE rich signal. The information from this type of signal provides absolute detail from the sample surface, but can be prone to charging with some highly nonconductive samples. Figure 2a shows the effect of charging while observing uncoated Teflon ™. The image becomes distorted with bright intermittent horizontal lines. Surface detail is enhanced due to the high contribution of SEs from the sample surface.When the electrode voltage is set negative, through the instrument GUI, the low energy secondary electrons are repelled providing a signal rich in backscattered electrons. The information from this type of signal provides compositional information and inherently reduces charging. The uncoated Teflon ™ sample in figure 2b shows all charging affects have been eliminated.
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Hasan, Kamrul, Sunil A. Patil, Dónal Leech, Cecilia Hägerhäll und Lo Gorton. „Electrochemical communication between microbial cells and electrodes via osmium redox systems“. Biochemical Society Transactions 40, Nr. 6 (21.11.2012): 1330–35. http://dx.doi.org/10.1042/bst20120120.
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Electrochemical communication between micro-organisms and electrodes is the integral and fundamental part of BESs (bioelectrochemical systems). The immobilization of bacterial cells on the electrode and ensuring efficient electron transfer to the electrode via a mediator are decisive features of mediated electrochemical biosensors. Notably, mediator-based systems are essential to extract electrons from the non-exoelectrogens, a major group of microbes in Nature. The advantage of using polymeric mediators over diffusible mediators led to the design of osmium redox polymers. Their successful use in enzyme-based biosensors and BFCs (biofuel cells) paved the way for exploring their use in microbial BESs. The present mini-review focuses on osmium-bound redox systems used to date in microbial BESs and their role in shuttling electrons from viable microbial cells to electrodes.
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Bond, Daniel R., und Derek R. Lovley. „Electricity Production by Geobacter sulfurreducens Attached to Electrodes“. Applied and Environmental Microbiology 69, Nr. 3 (März 2003): 1548–55. http://dx.doi.org/10.1128/aem.69.3.1548-1555.2003.
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ABSTRACT Previous studies have suggested that members of the Geobacteraceae can use electrodes as electron acceptors for anaerobic respiration. In order to better understand this electron transfer process for energy production, Geobacter sulfurreducens was inoculated into chambers in which a graphite electrode served as the sole electron acceptor and acetate or hydrogen was the electron donor. The electron-accepting electrodes were maintained at oxidizing potentials by connecting them to similar electrodes in oxygenated medium (fuel cells) or to potentiostats that poised electrodes at +0.2 V versus an Ag/AgCl reference electrode (poised potential). When a small inoculum of G. sulfurreducens was introduced into electrode-containing chambers, electrical current production was dependent upon oxidation of acetate to carbon dioxide and increased exponentially, indicating for the first time that electrode reduction supported the growth of this organism. When the medium was replaced with an anaerobic buffer lacking nutrients required for growth, acetate-dependent electrical current production was unaffected and cells attached to these electrodes continued to generate electrical current for weeks. This represents the first report of microbial electricity production solely by cells attached to an electrode. Electrode-attached cells completely oxidized acetate to levels below detection (<10 μM), and hydrogen was metabolized to a threshold of 3 Pa. The rates of electron transfer to electrodes (0.21 to 1.2 μmol of electrons/mg of protein/min) were similar to those observed for respiration with Fe(III) citrate as the electron acceptor (Eo′ =+0.37 V). The production of current in microbial fuel cell (65 mA/m2 of electrode surface) or poised-potential (163 to 1,143 mA/m2) mode was greater than what has been reported for other microbial systems, even those that employed higher cell densities and electron-shuttling compounds. Since acetate was completely oxidized, the efficiency of conversion of organic electron donor to electricity was significantly higher than in previously described microbial fuel cells. These results suggest that the effectiveness of microbial fuel cells can be increased with organisms such as G. sulfurreducens that can attach to electrodes and remain viable for long periods of time while completely oxidizing organic substrates with quantitative transfer of electrons to an electrode.
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DONKÓ, Z., und I. PÓCSIK. „ON THE FRACTAL STRUCTURE OF ELECTRON AVALANCHES“. Fractals 01, Nr. 04 (Dezember 1993): 939–46. http://dx.doi.org/10.1142/s0218348x9300099x.
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The motion of electrons in helium gas in the presence of a homogeneous external electric field was studied. Moving between the two electrodes, the electrons participate in elastic and inelastic collision processes with gas atoms. In ionizing collisions, secondary electrons are also created and in this way self-similar electron avalanches build up. The statistical distribution of the fractal dimension and electron multiplication of electron avalanches was obtained based on the simulation of a large number of electron avalanches. The fractal dimension shows a power-law dependence on electron multiplication with an exponent of ≈0.33.
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Stewart, IM. „The Distribution of Electrons in a Uniform Electric Field“. Australian Journal of Physics 48, Nr. 1 (1995): 89. http://dx.doi.org/10.1071/ph950089.
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Experiments are under way at the University of New England to measure the optical absorption of excited gas particles in a pre-breakdown discharge. Such measurements can be used to deduce the number density of electrons in the discharge. By comparing this experimental density map with the predictions of theory, electron transport parameters may be determined. In this paper, new theoretical expressions are derived for the number density distributions of electrons in a uniform electric field. These are found by solving the electron diffusion equation in a plane parallel electrode geometry with a radially symmetric cathodic current source. The contribution of ion-induced secondary current is included, and problems posed by non-equilibrium conditions near the electrodes are addressed. Techniques of data reduction are discussed with a particular emphasis on the avoidance of these problems.
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Wayama, Fumiya, Noriyuki Hatsugai und Yasuaki Okumura. „Bipyridines mediate electron transfer from an electrode to nicotinamide adenine dinucleotide phosphate“. PLOS ONE 17, Nr. 6 (16.06.2022): e0269693. http://dx.doi.org/10.1371/journal.pone.0269693.
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Biocatalysts are widely used in industry, but few examples of the use of oxidoreductases, in which enzymatic function often requires electrons, have been reported. NADPH is a cofactor that supplies an electron to oxidoreductases, but is consequently inactivated and no longer able to act as an electron donor. NADP+ can not receive electrons from electrodes through straightforward electrochemistry owing to its complicated three-dimensional structure. This study reports that bipyridines effectively mediate electron transfer between an electrode and NADP+, allowing them to serve as electron mediators for NADPH production. Using bipyridines, quinones, and anilines, which have negative oxidation–reduction potentials, an electrochemical investigation was conducted into whether electrons were transferred to NADP+. Only bipyridines with a reduction potential near -1.0 V exhibited electron transfer. Furthermore, the NADPH production level was measured using spectroscopy. NADPH was efficiently produced using bipyridines, such as methyl viologen and ethyl viologen, in which the bipyridyl 1- and 1’-positions bear small substituents. However, methyl viologen caused a dehydrogenation reaction of NADPH, making it unsuitable as an electron mediator for NADPH production. The dehydrogenation reaction did not occur using ethyl viologen. These results indicated that NADP+ can be reduced more effectively using substituents that prevent a dehydrogenation reaction at the bipyridyl 1- and 1’-positions while maintaining the reducing power.
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Zhakin, A. I., und A. E. Kuzko. „Ionization Processes of Negative Corona Discharge Part 1. Review and Experiment“. Proceedings of the Southwest State University. Series: Engineering and Technology 14, Nr. 1 (11.04.2024): 128–49. http://dx.doi.org/10.21869/2223-1528-2024-14-1-128-149.
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The purpose of the research is an experimental study of physical processes in the near-electrode zones of negative point electrodes in an electronegative gas (air) under the condition of a high-voltage field.Methods. Video image analysis, current-voltage characteristics measurements, and spectroscopy are used. The current-voltage characteristics of the corona discharge ignition voltage in the environment are measured, the problem of experimental identification of surface charges, the mechanism of negative corona discharge ignition, and the ionic structure of streamers is studied, degradation of electrodes during negative corona discharge, spectrum of corona discharge creation and electromagnetic sound.Results. It is shown that at small radii of curvature of needle electrodes, the development of a negative corona discharge is due to the cold emission of electrons, and on flat and slightly curved negative electrodes, due to the capture of surface electrons by electron-withdrawing molecules. The mechanism of ignition of a corona discharge in an electronegative gas with a negative needle, the structure of streamers from negative needles, the emission spectrum and ethonic degradation of electrodes have been studied.Conclusions. The ignition of a negative corona discharge at small radii of the tips of the pointed needles (ro less than tens of microns) is due to the cold emission of electrons followed by impact ionization of neutral molecules. With slightly curved electrodes, the appearance of a negative corona discharge is due to the capture of surface electrons by electronegative gas molecules with subsequent plasma-chemical reactions. The formation of surface electrons depends on many factors: the presence and structure of oxide films (roughness, defects, etc.), which determine the electron work function and form local fields at the tips of microtips. The appearance of a corona discharge leads to degradation of the corona electrodes, expressed in the spraying of the tips of the points and the melting of the needles. In the dark region of the negative corona discharge (U < U*), photons in the in the ultraviolet spectrum (UV spectrum) are emitted, and when U > U*, in addition to UV photons, photons in the visible region of the spectrum are emitted. Glow fluctuations are caused by the chaotic dynamics of the formation of injection centers (melted tubercles - ectons) on the surface of the corona electrode. The ignition of a corona discharge is accompanied by sound emission with a frequency of about 300 Hz.
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Ikeda, Shunsuke, Edward Beebe, Takeshi Kanesue, Sergey Kondrashev und Masahiro Okamura. „Double-sided detector for electron beam alignment and measurement of back-streaming electrons in ExtendedEBIS at BNL“. Journal of Physics: Conference Series 2244, Nr. 1 (01.04.2022): 012085. http://dx.doi.org/10.1088/1742-6596/2244/1/012085.
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Abstract We developed an electron beam detector installed between the superconducting solenoids in ExtentedEBIS. The detector is two-sided. Each side has 4 quadrant plates with an aperture slightly larger than the electron beam radius. The gun-side is for alignment of primary electron beam. The collector side detector is to measure the electrons back-streaming from the collector or the downstream electrodes to the cathode. It is important to understand how the back-streaming electrons behave and how to control it. The detector was designed with considerations of heat load. The influence on the electric potential distribution was investigated. A detector test showed that the back-streaming electrons were affected by the external electromagnetic fields and the space charge of the primary electron beam. It was proved that the behaviour of the electrons can be observed by this detector.
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Stenzel, Reiner L., Johannes Grünwald, Codrina Ionita, Roman Schrittwieser und Manuel Urrutia. „Sheaths and Double Layers with Instabilities“. Journal of Technological and Space Plasmas 2, Nr. 1 (24.03.2021): 70–92. http://dx.doi.org/10.31281/jtsp.v2i1.16.
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The properties of sheaths and associated potential structures and instabilities cover a broad field which even a review cannot cover everything. Thus, the focus will be on about a dozen examples, describe their observations and focus on the basic physical explanations for the effects, while further details are found in the references. Due to familiarity the review focuses mainly on the authors work but compared and referenced related work. The topics start with a high frequency oscillations near the electron plasma frequency. Low frequency instabilities also occur at the ion plasma frequency.The injection of ions into an electron-rich sheath widens the sheath and forms a double layer. Likewise, the injection of electrons into an ion rich sheath widens and establishes a double layer which occurs in free plasma injection into vacuum. The sheath widens and forms a double layer by ionization in an electron rich sheath. When particle fluxes in "fireballs" gets out of balance the double layer performs relaxation instabilities which has been studied extensively. Fireballs inside spherical electrodes create a new instability due to the transit time of trapped electrons. On cylindrical and spherical electrodes the electron rich sheath rotates in magnetized plasmas. Electrons rotate due to $\mathbf E \times \mathbf B_0$ which excites electron drift waves with azimuthal eigenmodes. Conversely a permanent magnetic dipole has been used as a negative electrode. The impact of energetic ions produces secondary electron emission, forming a ring of plasma around the magnetic equator. Such "magnetrons" are subject to various instabilities. Finally, the current to a positively biased electrode in a uniformly magnetized plasma is unstable to relaxation oscillations, which shows an example of global effects. The sheath at the electrode raises the potential in the flux tube of the electrode thereby creating a radial sheath which moves unmagnetized ions radially. The ion motion creates a density perturbation which affects the electrode current. If the electrode draws large currents the current disruptions create large inductive voltages on the electrode, which again produce double layers. This phenomenon has been seen in reconnection currents. Many examples of sheath properties will be explained. Although the focus is on the physics some examples of applications will be suggested such as neutral gas heating and accelerating, sputtering of plasma magnetrons and rf oscillators.
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Suzuki, Kosuke, Ayumu Terasaka, Tomoya Abe und Hiroshi Sakurai. „Modification of Electronic Structures with Lithium Intercalation in LixMn2O4 (x = 0 and 1) Studied by CRYSTAL14 Calculation Code“. Key Engineering Materials 790 (November 2018): 15–19. http://dx.doi.org/10.4028/www.scientific.net/kem.790.15.
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In this study, we calculate electronic structures for Mn2O4 and LiMn2O4 by using CRYSTAL14 ab-initio calculation code in order to understand electrode reaction mechanism of LixMn2O4 by lithiation/delithiation. Mulliken population analysis for all electrons show that the redox orbitals with lithiation and delithiation is O 2p orbitals. However, difference charge densities between majority and minority electrons indicate the change of distribution in Mn 3d orbitals by lithiation. This modification of distribution in Mn 3d orbitals suggests the change of electron configuration because the number of electrons at Mn atom is almost constant in Mulliken population analysis for all electrons. As a result, this modification of distribution in Mn 3d orbitals improves electron conductivity of this material.
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Konvalina, Ivo, Filip Mika, Stanislav Krátký, Eliška Materna Mikmeková und Ilona Müllerová. „In-Lens Band-Pass Filter for Secondary Electrons in Ultrahigh Resolution SEM“. Materials 12, Nr. 14 (19.07.2019): 2307. http://dx.doi.org/10.3390/ma12142307.
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Scanning electron microscopes come equipped with different types of detectors for the collection of signal electrons emitted from samples. In-lens detection systems mostly consist of several auxiliary electrodes that help electrons to travel in a direction towards the detector. This paper aims to show that a through-the-lens detector in a commercial electron microscope Magellan 400 FEG can, under specific conditions, work as an energy band-pass filter of secondary electrons that are excited by the primary beam electrons. The band-pass filter properties verify extensive simulations of secondary and backscattered electrons in a precision 3D model of a microscope. A unique test sample demonstrates the effects of the band-pass filter on final image and contrast with chromium and silver stripes on a silicon substrate, manufactured by a combination of e-beam lithography, wet etching, and lift-off technique. The ray tracing of signal electrons in a detector model predicate that the through-the-lens detector works as a band-pass filter of the secondary electrons with an energy window of about 3 eV. By moving the energy window along the secondary electron energy spectrum curve of the analyzed material, we select the energy of the secondary electrons to be detected. Energy filtration brings a change in contrast in the image as well as displaying details that are not otherwise visible.
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Fang, Xin, Shafeer Kalathil, Giorgio Divitini, Qian Wang und Erwin Reisner. „A three-dimensional hybrid electrode with electroactive microbes for efficient electrogenesis and chemical synthesis“. Proceedings of the National Academy of Sciences 117, Nr. 9 (12.02.2020): 5074–80. http://dx.doi.org/10.1073/pnas.1913463117.
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Integration of electroactive bacteria into electrodes combines strengths of intracellular biochemistry with electrochemistry for energy conversion and chemical synthesis. However, such biohybrid systems are often plagued with suboptimal electrodes, which limits the incorporation and productivity of the bacterial colony. Here, we show that an inverse opal-indium tin oxide electrode hosts a large population of current-producingGeobacterand attains a current density of 3 mA cm−2stemming from bacterial respiration. Differential gene expression analysis revealedGeobacter’s transcriptional regulations to express more electron-relaying proteins when interfaced with electrodes. The electrode also allows coculturing withShewanellafor syntrophic electrogenesis, which grants the system additional flexibility in converting electron donors. The biohybrid electrode containingGeobactercan also catalyze the reduction of soluble fumarate and heterogenous graphene oxide, with electrons from an external power source or an irradiated photoanode. This biohybrid electrode represents a platform to employ live cells for sustainable power generation and biosynthesis.
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Gudmundsson, J. T., Janez Krek, De-Qi Wen, E. Kawamura und M. A. Lieberman. „Surface effects in a capacitive argon discharge in the intermediate pressure regime“. Plasma Sources Science and Technology 30, Nr. 12 (01.12.2021): 125011. http://dx.doi.org/10.1088/1361-6595/ac3ba1.
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Abstract One-dimensional particle-in-cell/Monte Carlo collisional simulations are performed on a capacitive 2.54 cm gap, 1.6 Torr argon discharge driven by a sinusoidal rf current density amplitude of 50 A m−2 at 13.56 MHz. The excited argon states (metastable levels, resonance levels, and the 4p manifold) are modeled self-consistently with the particle dynamics as space- and time-varying fluids. Four cases are examined, including and neglecting excited states, and using either a fixed or energy-dependent secondary electron emission yield due to ion and/or neutral impact on the electrodes. The results for all cases show that most of the ionization occurs near the plasma-sheath interfaces, with little ionization within the plasma bulk region. Without excited states, secondary electrons emitted from the electrodes are found to play a strong role in the ionization process. When the excited states, and secondary electron emission due to neutral and ion impact on the electrodes are included in the discharge model, the discharge operation transitions from α-mode to γ-mode, in which nearly all the ionization is due to secondary electrons. Secondary electron production due to the bombardment of excited argon atoms was approximately14.7 times greater than that due to ion bombardment. Electron impact of ground state argon atoms by secondary electrons contributes about 76% of the total ionization; primary electrons, about 11%; metastable Penning ionization, about 13%; and multi-step ionization, about 0.3%.
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Strycharz, Sarah M., Trevor L. Woodard, Jessica P. Johnson, Kelly P. Nevin, Robert A. Sanford, Frank E. L�ffler und Derek R. Lovley. „Graphite Electrode as a Sole Electron Donor for Reductive Dechlorination of Tetrachlorethene by Geobacter lovleyi“. Applied and Environmental Microbiology 74, Nr. 19 (25.07.2008): 5943–47. http://dx.doi.org/10.1128/aem.00961-08.
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ABSTRACT The possibility that graphite electrodes can serve as the direct electron donor for microbially catalyzed reductive dechlorination was investigated with Geobacter lovleyi. In an initial evaluation of whether G. lovleyi could interact electronically with graphite electrodes, cells were provided with acetate as the electron donor and an electrode as the sole electron acceptor. Current was produced at levels that were ca. 10-fold lower than those previously reported for Geobacter sulfurreducens under similar conditions, and G. lovleyi anode biofilms were correspondingly thinner. When an electrode poised at −300 mV (versus a standard hydrogen electrode) was provided as the electron donor, G. lovleyi effectively reduced fumarate to succinate. The stoichiometry of electrons consumed to succinate produced was 2:1, the ratio expected if the electrode served as the sole electron donor for fumarate reduction. G. lovleyi effectively reduced tetrachloroethene (PCE) to cis-dichloroethene with a poised electrode as the sole electron donor at rates comparable to those obtained when acetate serves as the electron donor. Cells were less abundant on the electrodes when the electrodes served as an electron donor than when they served as an electron acceptor. PCE was not reduced in controls without cells or when the current supply to cells was interrupted. These results demonstrate that G. lovleyi can use a poised electrode as a direct electron donor for reductive dechlorination of PCE. The ability to colocalize dechlorinating microorganisms with electrodes has several potential advantages for bioremediation of subsurface chlorinated contaminants, especially in source zones where electron donor delivery is challenging and often limits dechlorination.
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Dedulewich, S., Z. Kancleris, A. Matulis und Yu Pozhela. „Electron-electron scattering in hot electrons“. Semiconductor Science and Technology 7, Nr. 3B (01.03.1992): B322—B323. http://dx.doi.org/10.1088/0268-1242/7/3b/081.
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Schultheiss, Katrin, Joachim Zach, Bjoern Gamm, Manuel Dries, Nicole Frindt, Rasmus R. Schröder und Dagmar Gerthsen. „New Electrostatic Phase Plate for Phase-Contrast Transmission Electron Microscopy and Its Application for Wave-Function Reconstruction“. Microscopy and Microanalysis 16, Nr. 6 (15.10.2010): 785–94. http://dx.doi.org/10.1017/s1431927610093803.
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AbstractA promising novel type of electrostatic phase plate for transmission electron microscopy (TEM) is presented. The phase plate consists of a single microcoaxial cable-like rod with its electrode exposed to the undiffracted electrons. The emerging field is used to shift the phase of the undiffracted electrons with respect to diffracted electrons. The design overcomes the drawback of the spatial frequency-blocking ring electrode of the Boersch phase plate. First, experimental phase-contrast images are presented for PbSe and Pt nanoparticles with clearly varying phase contrast, which depends on the applied voltage and resulting phase shift of the unscattered electrons. With the new phase-plate design, we show for the first time the reconstruction of an object wave function based on a series of only three experimental phase-contrast TEM images obtained with an electrostatic phase plate.
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Troyon, Michel, und He Ning Lei. „Electron Trajectories Calculations of an Energy - Filtering Field-Emission Gun“. Proceedings, annual meeting, Electron Microscopy Society of America 48, Nr. 1 (12.08.1990): 192–93. http://dx.doi.org/10.1017/s0424820100179713.
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In many cases, the contribution of beam energy spread to the limitation of the performances of an electron microscope is strong. In the case of the field emission gun (FEG) , Troyon has experimentally shown it is possible to reduce considerably the energy spread by energy filtering at the gun level. The system developed consists basically of a magnetic FEG with a retarding electrode working as the retarding electrode of an energy filter. The principle is recalled in Fig. 1 and the cross section of the accelerator is given in Fig. 2. In this paper, the results of electron trajectories calculations inside the energy filtering field emission gun (EFFEG) are given.Fig. 3 shows that electrons of same energy, but entering the retarding field with different angles, can have exit angles very different. Due to the work function of approximately 4.5 eV the electrons, for an extracting potential Vo = 2 kV, enter in the field of the retarding electrode with an energy smaller than 2 keV. In Fig. 3 trajectories are computed for an electron of 1996 eV. Electrons passing by the nodal points have the same entering and exit angles. Trajectory 1 in Fig. 3 corresponds to an entering radius re = 17.5 μm and an entering semi angle αe = 1.2 mrad. For these re and αe values, at Vr =6 V, the exit semi angle αs = αe . Fig. 3 shows that an electron entering parallely to the axis, even very close to the axis (re = 10 μm) has a larger exit angle than electrons passing by the nodal points.
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Komatsu, Tomohiro, Kazuki Hishii, Michiko Kimura, Satoshi Amaya, Hiroaki Sakamoto, Eiichiro Takamura, Takenori Satomura und Shin-ichiro Suye. „Highly Efficient Multi-Step Oxidation Bioanode Using Microfluidic Channels“. International Journal of Molecular Sciences 22, Nr. 24 (16.12.2021): 13503. http://dx.doi.org/10.3390/ijms222413503.
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With the rapid decline of fossil fuels, various types of biofuel cells (BFCs) are being developed as an alternative energy source. BFCs based on multi-enzyme cascade reactions are utilized to extract more electrons from substrates. Thus, more power density is obtained from a single molucule of substrate. In the present study, a bioanode that could extract six electrons from a single molecule of L-proline via a three-enzyme cascade reaction was developed and investigated for its possible use in BFCs. These enzymes were immobilized on the electrode to ensure highly efficient electron transfer. Then, oriented immobilization of enzymes was achieved using two types of self-assembled monolayers (SAMs). In addition, a microfluidic system was incorporated to achieve efficient electron transfer. The microfluidic system, in which the electrodes were arranged in a tooth-shaped comb, allowed for substrates to be supplied continuously to the cascade, which resulted in smooth electron transfer. Finally, we developed a high-performance bioanode which resulted in the accumulation of higher current density compared to that of a gold disc electrode (205.8 μA cm−2: approximately 187 times higher). This presents an opportunity for using the bioanode to develop high-performance BFCs in the future.
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Liu, Guan-Yu, Wei-Feng Sun und Qing-Quan Lei. „Charge Injection and Dielectric Characteristics of Polyethylene Terephthalate Based on Semiconductor Electrodes“. Materials 14, Nr. 6 (10.03.2021): 1344. http://dx.doi.org/10.3390/ma14061344.
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Employing a novel semiconductor electrode in comparison with the traditional semiconductor electrode made of polyethylene/ethylene-vinyl-acetate copolymer/carbon-black (PE/EVA/CB) composite, characteristic charge carriers are injected into polyethylene terephthalate (PET) as a polymer dielectric paradigm, which will be captured by specific deep traps of electrons and holes. Combined with thermal stimulation current (TSC) experiments and first-principles electronic-state calculations, the injected charges from the novel electrode are characterized, and the corresponding dielectric behavior is elucidated through DC conductance, electrical breakdown and dielectric spectrum tests. TSC experiments with novel and traditional semiconductor electrodes can distinguish the trapping characteristics between hole and electron traps in polymer dielectrics. The observable discrepancy in space charge-limited conductance and the stable dielectric breakdown strength demonstrate that the electron injection into PET film specimen is restricted by using the novel semiconductor electrode. Attributed to the favorable suppression on the inevitable electron injections from metal electrodes, adopting novel i-electrode can avoid the evident abatement of dipole orientation polarization caused by space charge clamp, but will engender the accessional high-frequency dielectric loss from dielectric relaxations of interface charges at i-electrodes.
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McGehee, Michael D. „Nanostructured Organic–Inorganic Hybrid Solar Cells“. MRS Bulletin 34, Nr. 2 (Februar 2009): 95–100. http://dx.doi.org/10.1557/mrs2009.27.
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AbstractWhen light is absorbed in organic semiconductors, bound electron–hole pairs known as excitons are generated. The electrons and holes separate from each other at an interface between two semiconductors by electron transfer. It is advantageous to form well-ordered nanostructures so that all of the excitons can reach the interface between the two semiconductors and all of the charge carriers have a pathway to the appropriate electrode. This article discusses charge and exciton transport in organic semiconductors, as well as the opportunities for making highly efficient solar cells and for using carbon nanotubes to replace metal oxide electrodes.
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ORCHARD, GLORIA M., und ANTHONY J. WAKER. „CHARACTERISTICS AND FUNCTION OF AN ELECTRON ATTACHMENT SPECTROMETER: PULSE FORMATION TIME AND GAIN EFFECTS IN P-10 GAS“. International Journal of Modern Physics: Conference Series 27 (Januar 2014): 1460141. http://dx.doi.org/10.1142/s2010194514601410.
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An Electron Attachment Spectrometer (EAS) has been designed to measure electron attachment in air and other gases. The aim of the EAS is to observe how parameters such as the electric field, reduced electric field and type of gas can influence electron attachment. The overall objective of this work is to investigate if the gas-gain of a proportional counter can be optimized by minimizing electron attachment with oxygen to improve the measurement of tritium-in-air. Current research interests include the measurement of the time between the generation of the electron–ion pairs and arrival of the electrons at the wire anode. Additionally, the study of the multiplication properties of the detector as a function of pulse formation time, P-10 gas flow rate and electric field will be presented. The EAS is a cylinder with a length of approximately 92 mm and diameter of 41 mm comprised of cylindrical hollow brass electrodes and Teflon spacers. A uniform electric field within the tube is applied and guides electrons and/or ions towards their respective electrodes. A proportional counter with a 50 μm diameter wire anode is used to detect the electrons and/or ions created by an 241 Am source located at the opposite end.
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Zhakin, A. I., und A. E. Kuzko. „Ionization processes of negative corona discharge. Part 2. Theory. Comparison with experiment“. Proceedings of the Southwest State University. Series: Engineering and Technology 14, Nr. 2 (02.07.2024): 122–41. http://dx.doi.org/10.21869/2223-1528-2024-14-2-122-141.
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The purpose of the research is a theoretical analysis of ionization processes in the air, which are initiated by a high-voltage field generated by the negative needle-flat electrode electrode system. Methods. Fe, Cu, Al electrodes are used. Calculations are carried out using the methods of quantum mechanics and mathematical physics. Results. The processes of cold and thermoelectron emission of electrons, enhanced by an external high-voltage field (Schottky emission), are analyzed. The conditions under which the generation of charges from the cathode surface due to plasma-chemical reactions and the capture of surface electrons by electronegative oxygen molecules are decisive are investigated. Based on the PE theory, a theory of injection of negative ions from the cathode into an electronegative gas is constructed and the theory is compared with experiment. It has been shown that at small radii of curvature of needle tips, when E ≥ 106 V/cm, the generation of charges is due to cold emission of electrons. In average fields E ≈ 105 V/cm, electron emission is due to the Schottky effect. In fields E ≈ 104 V/cm and below, injection is caused by electrochemical processes and PE capture. A theory has been developed for PEs that appear at electric field intensities on the electrode of the order of several tens of kV/cm, that is, on flat and slightly curved negative electrodes. The capture of PE by electron-withdrawing molecules causes an injection current and, as a consequence, the ignition of a corona discharge. Analytical expressions for the surface density as a function of the local electric field strength, as well as an expression for the injection current, are obtained. The agreement between theory and experiment is satisfactory. Conclusion. An analysis of the development of CR on negative needles is given. A theory of PE at the cathode in strong electric fields was developed. Based on the results of measuring dark negative current-voltage characteristics, it is possible to determine the patterns of surface processes involving electronic transitions, in particular, determine the concentration of PE and injection currents.
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Toth, M., und M. R. Phillips. „Space Charge Artifacts in ESEM Images: Shadowing and Contrast Reversal“. Microscopy and Microanalysis 6, S2 (August 2000): 774–75. http://dx.doi.org/10.1017/s1431927600036369.
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The environmental scanning electron microscope (ESEM) employs a series of pressure limiting apertures and a differential pumping system to allow for electron imaging at specimen chamber pressures of up to 50 torr. Images rich in secondary electron (SE) contrast can be obtained using the gaseous secondary electron detector (GSED) or ion current (Iion) signals. The GSED and Iion signals are amplified in a gas cascade. SEs emitted from a sample are accelerated through the gas in the specimen chamber by an electric field, EGSED, produced by a positively biased electrode located in the chamber, above the specimen. The accelerated SEs give rise to a cascade ionization process that can amplify the SE signal by up to three orders of magnitude. Electrons produced in the cascade are rapidly swept to the biased electrode and are efficiently removed from the gas. Positive ions produced in the cascade drift away from the electrode with a velocity that is at least three orders of magnitude lower than that of the electrons.
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Golden, Joel, Matthew D. Yates, Michelle Halsted und Leonard Tender. „Application of electrochemical surface plasmon resonance (ESPR) to the study of electroactive microbial biofilms“. Physical Chemistry Chemical Physics 20, Nr. 40 (2018): 25648–56. http://dx.doi.org/10.1039/c8cp03898h.
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Results reveal that for an electrode-grown Geobacter sulfurreducens biofilm, as much as 70% of cytochrome hemes residing within hundreds of nanometers from the electrode surface store electrons even as extracellular electron transport is occurring across the biofilm/electrode interface.
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McMorran, Benjamin J., Peter Ercius, Tyler R. Harvey, Martin Linck, Colin Ophus und Jordan Pierce. „Electron Microscopy with Structured Electrons“. Microscopy and Microanalysis 23, S1 (Juli 2017): 448–49. http://dx.doi.org/10.1017/s1431927617002926.
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Liu, Qingyu, Qinhe Zhang, Min Zhang und Fazhan Yang. „Study on the Discharge Characteristics of Single-Pulse Discharge in Micro-EDM“. Micromachines 11, Nr. 1 (01.01.2020): 55. http://dx.doi.org/10.3390/mi11010055.
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To further study the discharge characteristics and machining mechanism of micro-electrical discharge machining (micro-EDM), the variation trends of the discharge energy and discharge crater size with actual discharge duration are discussed based on single-pulse experiments. The polarity effect of micro-EDM was analyzed according to the motion characteristics of electrons and ions in the discharge plasma channel. The results show that the discharge current and voltage of micro-EDM were independent of the discharge width and open-circuit voltage. The energy utilization rate of the short-pulse discharge was relatively high, and the energy utilization rate decreased gradually as the discharge duration increased. Even if the mass of the positive ion was much larger than that of the electron, the kinetic energy of the positive ion was still less than that of the electron when bombarding the surface of the electrode. The acceleration and speed of electrons were very high, and the number of times that electrons bombarded the surface of positive electrode was more than 600 times that of positive ions bombarding the surface of the negative electrode during the same time.
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Medhisuwakul, M., Thiraphat Vilaithong und Jürgen Engemann. „A New Design and Computer Simulation of a 5-Electrode Ion Extraction/Focusing System“. Solid State Phenomena 107 (Oktober 2005): 21–24. http://dx.doi.org/10.4028/www.scientific.net/ssp.107.21.
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A 13.56 MHz radio-frequency (rf) driven multicusp ion source has been constructed [1] to produce a high argon ion current density. Milliampere-range argon ion current can be extracted from the source. An in-waveguide microwave plasma source has been utilized as the ion beam neutralizer [2]. The neutralization source was placed 20 cm downstream from the extraction system. With the former extraction system, comprised of extraction electrodes and an Einzel lens, the electrons from the neutralizer were attracted to the high positive potential of the lens. Consequently, the potential of the lens drops and the beam is diverged. To suppress electrons from being accelerated to the Einzel lens a negatively biased electrode was placed before the last electrode, which is grounded, to produce a retarding electric field for electrons. The hole of the electrode was made small to make sure that the potential at the center is negative enough to suppress electrons. All simulations have been performed with the KOBRA3-INP simulation software. The results of the beam shape from the simulation will be presented.
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Neděla, V., I. Konvalina, M. Oral und J. Hudec. „The Simulation of Energy Distribution of Electrons Detected by Segmental Ionization Detector in High Pressure Conditions of ESEM“. Microscopy and Microanalysis 21, S4 (Juni 2015): 264–69. http://dx.doi.org/10.1017/s1431927615013483.
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AbstractThis paper presents computed dependencies of the detected electron energy distribution on the water vapour pressure in an environmental scanning electron microscope obtained using the EOD software with a Monte Carlo plug-in for the electron-gas interactions. The software GEANT was used for the Monte Carlo simulations of the beam-sample interactions and the signal electron emission from the sample into the gaseous environment. The simulations were carried out for selected energies of the signal electrons collected by two electrodes with two different diameters with the voltages of +350 V and 0, respectively, and then 0 and +350 V, respectively, and for the distance of 2 mm between the sample and the detection electrodes of the ionization detector. The simulated results are verified by experimental measurements. Consequences of the simulated and experimental dependencies on the acquisition of the topographical or material contrasts using our ionization detector equipped with segmented detection electrode are described and discussed.
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UNNIKRISHNAN, C. S., und C. P. SAFVAN. „EXPERIMENTAL TEST OF A QUANTUM-LIKE THEORY: MOTION OF ELECTRONS IN A UNIFORM MAGNETIC FIELD, IN A VARIABLE POTENTIAL WELL“. Modern Physics Letters A 14, Nr. 07 (07.03.1999): 479–90. http://dx.doi.org/10.1142/s0217732399000535.
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We describe an experiment to test a quantum-like theory which predicts quantum-like behavior for an ensemble of electrons in a classical configuration with static magnetic and electric fields. Some of the earlier experiments had supporting evidence for anomalous, quantum-like effects in such a situation showing systematic modulations of electron current when a retarding potential is varied, even though the quantum wavelength of the electrons in such a configuration was less than a billionth of the spatial width of the potential well. Our experiment conclusively rules out any nonclassical, quantum-like behavior in electron transmission through simple electric barriers, when magnetic fields are present. We identify secondary electrons generated at various electrodes as the main source of apparent anomalous behavior. We also present a classical derivation of the quantum-like equation describing the modulations.
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Hauga, E. „Electron-electron bremsstrahlung for bound target electrons“. European Physical Journal D 49, Nr. 2 (26.08.2008): 193–99. http://dx.doi.org/10.1140/epjd/e2008-00156-5.
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Marugán, Javier, Rafael van Grieken, Cristina Pablos, Cristina Adán und Ruud Timmers. „Determination of Photochemical, Electrochemical and Photoelectrochemical Efficiencies in a Photoelectrocatalytic Reactor“. International Journal of Chemical Reactor Engineering 11, Nr. 2 (20.06.2013): 787–97. http://dx.doi.org/10.1515/ijcre-2012-0014.
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Abstract The relation between the amount of incident photons, absorbed photons, oxidant species, reaction products and electrons in the external circuit should be analyzed individually to determine the step limiting the efficiency of the global photoelectrocatalytic processes. This work discusses the evaluation of three different titania electrodes for the oxidation of methanol in a photoelectrocatalytic reactor. The electrode prepared with three titania coating cycles shows a high efficiency in terms of photochemical (photons to product molecules), electrochemical (product molecules to electrons) and photoelectrochemical (photons to electrons) what explain its high activity for the photoelectrocatalytic oxidation of methanol.
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Stetsun, A. I. „The Density of MoSi2 Electron States for the Amorphous Film“. Фізика і хімія твердого тіла 17, Nr. 3 (15.09.2016): 372–74. http://dx.doi.org/10.15330/pcss.17.3.372-374.
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The density of MoSi2 electron states for the amorphous film has been calculated. An electron states at the top of valence band for this material are provided d electrons of molybdenum, p electrons of silicon and p electrons of molybdenum. d electrons of molybdenum are significant especially for physical properties of MoSi2.
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AMEMIYA, H., B. M. ANNARATONE und J. E. ALLEN. „The double sheath associated with electron emission into a plasma containing negative ions“. Journal of Plasma Physics 60, Nr. 1 (August 1998): 81–93. http://dx.doi.org/10.1017/s0022377898006837.
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The double sheath formed by thermal electrons and negative ions in a plasma and electrons emitted from an electrode is investigated. The ion energy at the sheath edge and the electric field at the electrode surface are calculated for several values of the ratio of negative-ion density to electron density. The maximum beam density above which a virtual cathode appears is given. The relation to the Langmuir limit is shown. The numerical results for the electric potential, the electric field and the space charge density are presented. The floating potential is calculated from the current balance of all components.
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Roullier, Charlotte, Melania Reggente, Pierrick Gilibert und Ardemis Anoush Boghossian. „Polypyrrole Electrodes Show Strain-Specific Enhancement of Photocurrent from Cyanobacteria“. ECS Meeting Abstracts MA2023-01, Nr. 42 (28.08.2023): 2360. http://dx.doi.org/10.1149/ma2023-01422360mtgabs.
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Except for a limited number of exoelectrogens, most microbes of interest are surrounded by insulating membranes impairing an efficient extracellular electron transfer. This study focuses on the fabrication of a conductive polypyrrole (PPy) based coating for enhancing microbial charge extraction. The polymer deposition was characterized and optimized using a combination of potentiodynamic and potentiostatic measurements as well as scanning electron microscopy (SEM), energy dispersive X-Ray (EDX) analysis, and Raman spectroscopy. The electrodes were used to extract photosynthetic electrons from the cyanobacteria Synechocystis sp. PCC6803 and Synechococcus Elongatus PCC7942. The PPy electrode showed a six-fold increase in extracted photocurrent for Synechocystis under unmediated conditions compared to bare graphite electrodes. This enhancement was attributed to decreased resistivity and increased electroactive surface area of the PPy electrode. By contrast, Elongatus showed no substantial difference in photocurrent between the PPy and bare electrodes. A comparison of the zeta potential and adherence of the cells suggested more limited charge interaction of Elongatus cells with the PPy surface compared to the Synechocystis cells indicating a strain-specific enhancement of these electrodes.
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Haddad, Raoudha, Jean-Gabriel Mattei, Jessica Thery und Aurélien Auger. „Novel ferrocene-anchored ZnO nanoparticle/carbon nanotube assembly for glucose oxidase wiring: application to a glucose/air fuel cell“. Nanoscale 7, Nr. 24 (2015): 10641–47. http://dx.doi.org/10.1039/c5nr00497g.
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Glucose oxidase is immobilized on a ZnO-Fc nanoparticle modified electrode. The new architecture of ZnO supported electron mediators to shuttle electrons from the redox centre of the enzyme to the surface of the working electrode can bring about successful glucose oxidation.
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Seol, Youbin, Hong Young Chang, Seung Kyu Ahn und Shin Jae You. „Effect of mixing CF4 with O2 on electron characteristics of capacitively coupled plasma“. Physics of Plasmas 30, Nr. 1 (Januar 2023): 013503. http://dx.doi.org/10.1063/5.0120850.
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Effect of mixing CF4 with O2 on electron parameters in capacitively coupled RF plasma was studied. Adding CF4 gas to fixed O2 flow, electron energy probability functions were measured by a Langmuir probe method. As the CF4 gas was added, the decrease in the probability of low energy electrons was observed. The proportion of low energy electrons decreased gradually as the CF4 gas ratio increased, respectively. From electron energy probability functions, electron densities and electron temperatures were calculated. As the CF4 gas ratio increased, electron density decreased and electron temperature increased. Collision cross sections of low energy electrons can explain electron parameter behaviors. By the strong electron attachment of fluorine species which were generated from CF4, low energy electrons depleted by attachment, and the overall electron temperature increased. However, as the elastic collision cross section of CF4 is not different from that of O2, the heating mechanism and physics of high energy electrons did not change.
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Rourk, Christopher, Yunbo Huang, Minjing Chen und Cai Shen. „Indication of Strongly Correlated Electron Transport and Mott Insulator in Disordered Multilayer Ferritin Structures (DMFS)“. Materials 14, Nr. 16 (12.08.2021): 4527. http://dx.doi.org/10.3390/ma14164527.
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Electron tunneling in ferritin and between ferritin cores (a transition metal (iron) oxide storage protein) in disordered arrays has been extensively documented, but the electrical behavior of those structures in circuits with more than two electrodes has not been studied. Tests of devices using a layer-by-layer deposition process for forming multilayer arrays of ferritin that have been previously reported indicate that strongly correlated electron transport is occurring, consistent with models of electron transport in quantum dots. Strongly correlated electrons (electrons that engage in strong electron-electron interactions) have been observed in transition metal oxides and quantum dots and can create unusual material behavior that is difficult to model, such as switching between a low resistance metal state and a high resistance Mott insulator state. This paper reports the results of the effect of various degrees of structural homogeneity on the electrical characteristics of these ferritin arrays. These results demonstrate for the first time that these structures can provide a switching function associated with the circuit that they are contained within, consistent with the observed behavior of strongly correlated electrons and Mott insulators.
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VALERI, SERGIO, und ALESSANDRO di BONA. „MODULATED ELECTRON EMISSION BY SCATTERING-INTERFERENCE OF PRIMARY ELECTRONS“. Surface Review and Letters 04, Nr. 01 (Februar 1997): 141–60. http://dx.doi.org/10.1142/s0218625x9700016x.
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We review the effects of scattering-interference of the primary, exciting beam on the electron emission from ordered atomic arrays. The yield of elastically and inelastically backscattered electrons, Auger electrons and secondary electrons shows a marked dependence on the incidence angle of primary electrons. Both the similarity and the relative importance of processes experienced by incident and excident electrons are discussed. We also present recent studies of electron focusing and defocusing along atomic chains. The interplay between these two processes determines the in-depth profile of the primary electron intensity anisotropy. Finally, the potential for surface-structural studies and limits for quantitative analysis are discussed, in comparison with the Auger electron diffraction (AED) and photoelectron diffraction (PD) techniques.
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Kirdyashev, K. P. „Anomalous transport of electrons in an electric discharge with transverse magnetic field“. Journal of Physics: Conference Series 2056, Nr. 1 (01.10.2021): 012050. http://dx.doi.org/10.1088/1742-6596/2056/1/012050.
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Abstract The experimental data showing the relationship of excitation of microwave oscillations with abnormally transport of electrons across the magnetic field in turbulent plasma are presented. The mechanism of the formation of the discharge current due to scattering of drift electrons in the near-electrode layers of the electric discharges on microwave oscillations has been substantiated. The conditions for the manifestation of the turbulent mechanism of anomalous electron transport through the magnetic barrier at the boundary of the toroidal electric discharge have been studied most fully. The mobility of electrons across a magnetic field is one of the main parameters of electric discharges that use crossed electric and magnetic fields for technological purposes.
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Al-Owais, A., und I. S. El-Hallag. „Investigation of The Electrode Pathway of Quinoline Azo Dye Compound via Convolutive Voltammetry and Digital Simulation“. Journal of New Materials for Electrochemical Systems 19, Nr. 2 (30.06.2016): 091–95. http://dx.doi.org/10.14447/jnmes.v19i2.335.
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The electrochemical behavior and the electrode reaction of quinolone azo dye compound was investigated using convolutive cyclic voltammetry at mercury electrode in 50% (v/v) ethanolic Britton-Robinson solutions of pH 2.5 – 12.0. Four electrons slow reduction wave was consumed in acidic and alkaline solutions corresponding to the reduction of the more easily N = N center. A second more cathodic irreversible , pH – dependent, 2-electron wave represents the reduction of quinolone ring. Cyclic voltammetry and convolution transforms were used to determine the kinetic parameters of the electroactive species.The extracted electrochemical parameters were confirmed via digital simulation.Controlled potential coulometry technique was used for calculation the overall number of electrons involved in electrode reaction.
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Nishide, Hiroyuki, Kenichiroh Koshika und Kenichi Oyaizu. „Environmentally benign batteries based on organic radical polymers“. Pure and Applied Chemistry 81, Nr. 11 (15.10.2009): 1961–70. http://dx.doi.org/10.1351/pac-con-08-12-03.
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A radical polymer is an aliphatic organic polymer bearing densely populated unpaired electrons in the pendant robust radical groups per repeating unit. These radicals’ unpaired electrons are characterized by very fast electron-transfer reactivity, allowing reversible charging as the electrode-active materials for secondary batteries. Organic-based radical batteries have several advantages over conventional batteries, such as increased safety, adaptability to wet fabrication processes, easy disposability, and capability of fabrication from less-limited resources, which are described along the fashion of green chemistry.
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Rigler, Mark, und William Longo. „High Voltage Scanning Electron Microscopy Theory and Applications“. Microscopy Today 2, Nr. 5 (August 1994): 12–13. http://dx.doi.org/10.1017/s1551929500066256.
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A variety of energy emissions occur as a result of primary beam interaction with the specimen surface. Secondary electrons, x-rays, visible photons, near IR photons, and Auger electrons are emitted during inelastic scattering of electrons. Backscattered electrons (BSE) are emitted during elastic scattering of primary electrons. Backscattered electrons are those electrons which pass through the electron cloud of an atom and change direction without much energy loss. BSEs may diffuse into the sample or may escape from the sample surface. In practice, the primary electron beam penetrates deeply into low Z (atomic number) materials and produces few BSEs while high Z materials retard primary beam penetration and emit large numbers of BSEs. According to Murata et al., the higher the atomic number, the smaller the mean free path between electron scattering events (i.e. 528 Å for Al vs. 50 Å for Au at 30 KeV) and the higher the probability of scattering.
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Son, Dong Hee. „(Invited) Upconverted Hot Electrons from Semiconductor Nanocrystals for Enhancing Photocatalysis“. ECS Meeting Abstracts MA2024-01, Nr. 35 (09.08.2024): 1984. http://dx.doi.org/10.1149/ma2024-01351984mtgabs.
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The exciton-to-hot electron upconversion phenomenon in Mn-doped semiconductor quantum dots (QDs) produces highly energetic hot electrons. These electrons have an average energy just a fraction of 1 eV below the vacuum level, with a subpopulation of hot electrons existing above the vacuum level. This hot electron upconversion process is similar to photon upconversion in lanthanide-doped nanoparticles. However, the final state here is a highly excited hot electron in the conduction band of the host QDs, not a state emitting higher-energy photons. These upconverted hot electrons can be harnessed to carry out thermodynamically and kinetically challenging reduction reactions, benefiting from their high excess kinetic energy and long-range transfer capability. The presentation will discuss recent demonstrations of the benefits of these upconverted hot electrons in various photocatalytic reduction and redox-neutral reactions. Additionally, the development of new materials for more efficient hot electron upconversion and the potential to broaden the application of these energetic hot electrons beyond photocatalysis will be discussed.
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Chernomorskii, A. I. „The Correlation Between the Electronegativities and the Standard Potentials“. Journal of The Electrochemical Society 168, Nr. 11 (01.11.2021): 116514. http://dx.doi.org/10.1149/1945-7111/ac3a26.
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The linear correlations are analyzed between the empirical electronegativities χ a of metals and non-metals and their standard potentials E o . The correlation intersection corresponds to the transfer from metals to non-metals, characterized by the intermediate electronegativity χ a,interm and the standard potential E o ∼+ 0.5 V SHE which is close to Billiter potential +0.475 V SHE. The electronegativity χ a,interm and E o ∼ +0.5 V SHE would correspond to some hypothetical substance (neither metal nor non-metal) without own chemical actiity. This would be due to the intermediate non-specific (definite coulomb) bond of its outer electrons. This bond is not enough unstable (as metallic bonds) for breaking and not enough stable (as non-metallic bonds) for accepting electrons. Spontaneous half-reactions-interactions of Red - and Ox - forms on electrodes are due to the break Red + H2O → Ox + ne interm and formation Ox + ne interm + H2O → Red of specific (chemical) electron bonds with Ox-forms, where ne interm are electrons without specific bond with Ox-forms. The instant division of electrons ne interm, ions and polarized water molecules of formed intermediate complexes leads to the appearance of double-electric layers on electrodes.
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Xie, Mengjun, Dagang Liu, Huihui Wang und Laqun Liu. „Study on the Correlation between Magnetic Field Structure and Cold Electron Transport in Negative Hydrogen Ion Sources“. Applied Sciences 12, Nr. 9 (19.04.2022): 4104. http://dx.doi.org/10.3390/app12094104.
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In most negative hydrogen ion sources, an external magnet is installed near the extraction region to reduce the electron temperature. In this paper, the self-developed CHIPIC code is used to simulate the mechanism of a magnetic filter system, in the expansion region of the negative hydrogen ion source, on “hot” electrons. The reflection and the filtering processes of “hot” electrons are analyzed in depth and the energy distribution of electrons on the extraction surface is calculated. Moreover, the effects of different collision types on the density distribution of “cold” electrons along the X-axis and the spatial distribution of “cold” electrons on the X−Z plane are discussed. The numerical results show that the electron reflection is caused by the magnetic mirror effect. The filtering of “hot” electrons is due to the fact that the magnetic field constrains most of the electrons from reaching the vicinity of the extraction surface, being that collisions cause a decay in electron energy. Excitation collision is the main decay mechanism for electron energy in the chamber. The numerical results help to explain the formation process of “cold” electrons at the extraction surface, thus providing a reference for reducing the loss probability of H−.
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Petrov, G. M., und A. Davidson. „Collisional and transport parameters of Cu in the warm dense matter regime calculated using the average atom model“. Plasma Physics and Controlled Fusion 63, Nr. 12 (02.11.2021): 125011. http://dx.doi.org/10.1088/1361-6587/ac2e3f.
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Abstract Collisional and transport parameters for Cu are computed using the average atom model. Transition metals such as copper are difficult to model within the framework of the average atom model due to the presence of a narrow band of 3d electrons that mix and hybridize with the broad 4s band of nearly-free electrons. With electron temperature increasing, the 3d electrons play a key role in the thermodynamics and transport properties of Cu (Lin et al 2008 Phys. Rev. B 77 075133), as well as the stability of the lattice (Loboda et al 2011 High Energy Density Phys. 7 361). In this work, the average atom model was used to track the average energy of the 3d band and its evolution with electron temperature. At room temperature, its center is at ∼6 electron volts (eV), a few electron-volts below the Fermi energy, and with electron temperature increasing it sinks relative to it. At electron temperature of about 8 eV the 3d electrons leave the conduction band and become bound. A long-standing problem related to the average ion charge observed by conduction band electrons is addressed and successfully resolved. A work-around has been found that predicts the correct average ion charge, Z ˉ , by formally introducing a third group of electrons: quasi-bound electrons. Benchmarking with published data is made that shows good agreement.