Fusion plasma losses due to the charge exchange of injected neutrals

International Nuclear Information System (INIS)

Bender, D.J.; Carlson, G.A.

1975-01-01

The interaction of a neutral beam, consisting of full, half and third energy components, with a mirror plasma is analyzed. The beam-plasma interaction is assumed to occur via ionization and charge exchange collisions. The plasma was approximated as being spherical in shape, having a uniform density, isotropic velocity distribution, and a mirror plasma energy distribution. It was found that to a first approximation, for plasma energies less than 100 keV, the charge exchange power loss (per injected atom) of the half energy component is at least twice that of the full energy component. For the third energy component, the loss is at least three times that of the full energy component. For some plasma conditions, the neutral beam can act as an energy sink for the plasma due to these charge exchange losses. (U.S.)

Charge-discharge characteristics of nickel/zinc battery with polymer hydrogel electrolyte

Energy Technology Data Exchange (ETDEWEB)

Iwakura, Chiaki; Murakami, Hiroki; Nohara, Shinji; Furukawa, Naoji; Inoue, Hiroshi [Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531 (Japan)

2005-12-01

A new nickel/zinc (Ni/Zn) battery was assembled by using polymer hydrogel electrolyte prepared from cross-linked potassium poly(acrylate) and KOH aqueous solution, and its charge-discharge characteristics were investigated. The experimental Ni/Zn cell with the polymer hydrogel electrolyte exhibited well-defined charge-discharge curves and remarkably improved charge-discharge cycle performance, compared to that with a KOH aqueous solution. Moreover, it was found that dendritic growth hardly occurred on the zinc electrode surface during charge-discharge cycles in the polymer hydrogel electrolyte. These results indicate that the polymer hydrogel electrolyte can successfully be used in Ni/Zn batteries as an electrolyte with excellent performance. (author)

Charge-discharge characteristics of nickel/zinc battery with polymer hydrogel electrolyte

Science.gov (United States)

Iwakura, Chiaki; Murakami, Hiroki; Nohara, Shinji; Furukawa, Naoji; Inoue, Hiroshi

A new nickel/zinc (Ni/Zn) battery was assembled by using polymer hydrogel electrolyte prepared from cross-linked potassium poly(acrylate) and KOH aqueous solution, and its charge-discharge characteristics were investigated. The experimental Ni/Zn cell with the polymer hydrogel electrolyte exhibited well-defined charge-discharge curves and remarkably improved charge-discharge cycle performance, compared to that with a KOH aqueous solution. Moreover, it was found that dendritic growth hardly occurred on the zinc electrode surface during charge-discharge cycles in the polymer hydrogel electrolyte. These results indicate that the polymer hydrogel electrolyte can successfully be used in Ni/Zn batteries as an electrolyte with excellent performance.

The charge transfer characteristic of tetraphenylporphyrin iron chloride Langmuir–Blodgett films

International Nuclear Information System (INIS)

Du, Y.; Li, Z.H.; Qi, P.; Wang, F.; Liu, D.

2013-01-01

The charge transfer characteristic of tetraphenylporphyrin iron (III) chloride (FeP) Langmuir–Blodgett (LB) films on the surface of the ITO glass electrode was reported. When the cyclic voltammetry (CV) scanning was running, the charge transfer characteristic was controlled by the oxidation–reduction process of Fe(III)/Fe(II). The charge transfer characteristic was related to the following factors: the cross-sectional area, relative to the electrode, of FeP as the electron donor (or acceptor). The greater the cross-sectional area of the aggregation of FeP as the electron donor (or acceptor) was, the larger the number of the donated (or accepted) electrons was. The projected area of the cross-section on the ITO electrode. The greater the projected area was, the larger the number of the donated (or accepted) electrons was. The distance between the center of the electron donor (or acceptor) of FeP and the surface of ITO electrode. The smaller the distance was, the greater the rate of donating (or accepting) electrons was. The monolayer coverage, which formed because of the FeP lying on the ITO surface in the form of the monomer and aggregate, was more sensitive to detect oxygen

Decay characteristics of electronic charged states of Si quantum dots as evaluated by an AFM/Kelvin probe technique

International Nuclear Information System (INIS)

Nishitani, Junichiro; Makihara, Katsunori; Ikeda, Mitsuhisa; Murakami, Hideki; Higashi, Seiichiro; Miyazaki, Seiichi

2006-01-01

Si quantum dots (Si-QDs) with an areal dot density of 8 x 10 11 cm -2 on SiO 2 have been prepared by the thermal decomposition of monosilane to characterize charged states of Si-QDs using AFM/Kelvin probe force microscopy (KFM). The temporal changes in the surface potential induced by electron charging and discharging at Si-QDs covered with a ∼ 2-nm-thick oxide layer have been measured. In electron charging and discharging at Si-QDs, a Rh-coated AFM tip was electrically biased in the range of - 5 to 5 V and scanned on the sample surface in a tapping mode. The surface potential changes on Si-QDs by electron injection and extraction were observable, while no potential change was detected elsewhere. The surface potential of charged Si-QDs decays with time at rates depending on charge injection conditions. The observed decay characteristics can be interpreted in terms of discharging of stored electrons in Si-QDs due to electron tunneling through the bottom oxide to the substrate and neutralization of stored holes due to recombination with electrons tunneling from the substrates. The defect generation in oxide is likely to be responsible for a fairly slow decay as observed in the case of electron extraction by the tip bias as high as + 4.8 V with respect to p-Si(100)

Early-stage aggregation in three-dimensional charged granular gas

Science.gov (United States)

Singh, Chamkor; Mazza, Marco G.

2018-02-01

Neutral grains made of the same dielectric material can attain considerable charges due to collisions and generate long-range interactions. We perform molecular dynamic simulations in three dimensions for a dilute, freely cooling granular gas of viscoelastic particles that exchange charges during collisions. As compared to the case of clustering of viscoelastic particles solely due to dissipation, we find that the electrostatic interactions due to collisional charging alter the characteristic size, morphology, and growth rate of the clusters. The average cluster size grows with time as a power law, whose exponent is relatively larger in the charged gas than the neutral case. The growth of the average cluster size is found to be independent of the ratio of characteristic Coulomb to kinetic energy, or equivalently, of the typical Bjerrum length. However, this ratio alters the crossover time of the growth. Both simulations and mean-field calculations based on Smoluchowski's equation suggest that a suppression of particle diffusion due to the electrostatic interactions helps in the aggregation process.

Parenting Stress in CHARGE Syndrome and the Relationship with Child Characteristics.

Science.gov (United States)

Wulffaert, Josette; Scholte, Evert M; Dijkxhoorn, Yvette M; Bergman, Jorieke E H; van Ravenswaaij-Arts, Conny M A; van Berckelaer-Onnes, Ina A

2009-08-01

This study investigates the parental perception of stress related to the upbringing of children with CHARGE syndrome and its association with behavioral and physical child characteristics. Parents of 22 children completed the Nijmegen Parenting Stress Index-Short, Developmental Behavior Checklist, and Dutch Vineland Screener 0-12 and reported their child's problems with hearing, vision and ability to speak. Parenting stress was high in 59% of the subjects. Behavioral problems on the depression, autism, self-absorbed and disruptive behavior scales correlated positively with parenting stress. A non-significant trend was found, namely higher stress among the parents of non-speaking children. No associations were found with other child characteristics, i.e. level of adaptive functioning and intellectual disability, auditory and visual problems, deafblindness, gender, and age. Raising a child with CHARGE syndrome is stressful; professional support is therefore essential for this population. More research into other possible influencing characteristics is needed to improve family-oriented interventions. Since CHARGE is a rare syndrome, closer international collaboration is needed, not only to expand the group of study subjects to increase statistical power, but also to harmonize research designs and measurement methods to improve the validity, the reliability, and the generalization of the findings.

Supercapacitor performance evaluation in replacing battery based on charging and discharging current characteristics

Science.gov (United States)

Sani, A.; Siahaan, S.; Mubarakah, N.; Suherman

2018-02-01

Supercapacitor is a new device of energy storage, which has much difference between ordinary capacitors and batteries. Supercapacitor have higher capacitance and energy density than regular capacitors. The supercapacitor also has a fast charging time, as well as a long life. To be used as a battery replacement please note the internal parameters of the battery to be replaced. In this paper conducted a simulation study to utilize supercapacitor as a replacement battery. The internal parameters of the battery and the supercapacitor are obtained based on the characteristics of charging and discharging current using a predefined equivalent circuit model. The battery to be replaced is a 12-volt lead-acid type, 6.5 Ah which is used on motorcycles with 6A charging and discharging currents. Super capacitor replacement capacitor is a capacity of 1600F, 2.7V which is connected in series as many as 6 pieces with 16.2 volt terminal voltage and charging current 12A. To obtain the same supercapacitor characteristic as the battery characteristic to be replaced, modification of its internal parameters is made. The results show that the super-capacitor can replace the battery function for 1000 seconds.

Improved memory characteristics by NH3-nitrided GdO as charge storage layer for nonvolatile memory applications

International Nuclear Information System (INIS)

Liu, L.; Xu, J. P.; Ji, F.; Chen, J. X.; Lai, P. T.

2012-01-01

Charge-trapping memory capacitor with nitrided gadolinium oxide (GdO) as charge storage layer (CSL) is fabricated, and the influence of post-deposition annealing in NH 3 on its memory characteristics is investigated. Transmission electron microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction are used to analyze the cross-section and interface quality, composition, and crystallinity of the stack gate dielectric, respectively. It is found that nitrogen incorporation can improve the memory window and achieve a good trade-off among the memory properties due to NH 3 -annealing-induced reasonable distribution profile of a large quantity of deep-level bulk traps created in the nitrided GdO film and reduction of shallow traps near the CSL/SiO 2 interface.

Enhanced ionic conductivity in composite materials due to interfacial space charge layers

International Nuclear Information System (INIS)

Dudney, N.J.

1985-01-01

The ionic conductivity of a number of salts (e.g., β-AgI, LiI, CuCl, HgI 2 , etc.) can be enhanced by one to three orders of magnitude with the addition of fine particles of an insoluble and nonconducting material such as Al 2 O 3 or SiO 2 . Typically the conductivity increases with addition of the inert particles and reaches a peak at 10-40 vol % of the particles. The mechanism responsible for the enhanced conductivity of the composite is not understood at this time. Some claim that this effect is due to an increased concentration of charge carriers in a diffuse space charge layer near the charged surface of the particle. The goal of the present study is to test this proposed mechanism by calculating the maximum space charge layer effect and then using this result to estimate the conductivity of a composite with a random distribution of Al 2 O 3 particles. Also, the conductivity of composite systems has been investigated assuming an ordered distribution of particles which are surrounded by a high conductivity layer

Charged particle emission effects on the characteristics of glow discharges with oscillating electrons

CERN Document Server

Nikulin, S P

2001-01-01

One discusses the effect of selection of charged particles on conditions to maintain and the characteristics of a glow discharge with oscillating electrons. It is shown that there is a pressure dependent optimal level of ion selection when the energy efficiency of ion source reaches its maximum value. It is determined that departure of fast ionizing electrons affects negatively the discharge maintenance wile emission of slow plasma electrons may promote maintenance of a discharge high current shape. It is shown that high efficient electron emission without violation of a discharge stability may take place in a magnetic field due to different nature of spatial distributions of fast and slow particles in discharges with electron oscillation

Perihelic shift of planets due to the gravitational field of the charged Sun

International Nuclear Information System (INIS)

Teli, M.T.; Palaskar, D.

1984-01-01

The perihelic shift of planets due to the charged Sun is calculated. The results when compared with experimental shifts suggest that the planets Mercury, Venus and Icarus do not possess self-electromagnetic fields

High-LET dose-response characteristics by track structure theory of heavy charged particles

International Nuclear Information System (INIS)

Hansen, J.W.; Olsen, K.J.

1981-09-01

The track structure theory developed by Katz and co-workers ascribes the effect of high-LET radiation to the highly inhomogeneous dose distribution due to low energy Δ-rays ejected from the particle track. The theory predicts the effectiveness of high-LET radiation by using the ion parameters zsub(eff') effective charge of the ion, and β = v/c, the relative ion velocity, together with the characteristic dose D 37 derived from low-LET dose-response characteristic of the detector and the approximate size asub(0) of the sensitive element of the detector. 60 Co gamma-irradiation is used as a reference low-LET radiation, while high-LET radiation ranging from 16 MeV protons to 4 MeV/amu 16 0-ions covering an initial LET range of 30-5500 MeVcm 2 /g is obtained from a tandem Van de Graaff accelerator. A thin film (5mg/cm 2 ) radiochromic dye cyanide plastic dosemeter was used as detector with the characteristic dose of 16.8 Mrad and a sensitive element size of 10 -7 cm. Theoretical and experimental effectiveness, RBE, agreed within 10 to 25% depending on LET. (author)

Radiation induced leakage due to stochastic charge trapping in isolation layers of nanoscale MOSFETs

Science.gov (United States)

Zebrev, G. I.; Gorbunov, M. S.; Pershenkov, V. S.

2008-03-01

The sensitivity of sub-100 nm devices to microdose effects, which can be considered as intermediate case between cumulative total dose and single event errors, is investigated. A detailed study of radiation-induced leakage due to stochastic charge trapping in irradiated planar and nonplanar devices is developed. The influence of High-K insulators on nanoscale ICs reliability is discussed. Low critical values of trapped charge demonstrate a high sensitivity to single event effect.

Gain reduction due to space charge at high counting rates in multiwire proportional chambers

International Nuclear Information System (INIS)

Smith, G.C.; Mathieson, E.

1986-10-01

Measurements with a small MWPC of gas gain reduction, due to ion space charge at high counting rates, have been compared with theoretical predictions. The quantity ln(q/q 0 )/(q/q 0 ), where (q/q 0 ) is the relative reduced avalanche charge, has been found to be closely proportional to count rate, as predicted. The constant of proportionality is in good agreement with calculations made with a modified version of the original, simplified theory

Fabrication of solid-state secondary battery using semiconductors and evaluation of its charge/discharge characteristics

Science.gov (United States)

Sasaki, Atsuya; Sasaki, Akito; Hirabayashi, Hideaki; Saito, Shuichi; Aoki, Katsuaki; Kataoka, Yoshinori; Suzuki, Koji; Yabuhara, Hidehiko; Ito, Takahiro; Takagi, Shigeyuki

2018-04-01

Li-ion batteries have attracted interest for use as storage batteries. However, the risk of fire has not yet been resolved. Although solid Li-ion batteries are possible alternatives, their performance characteristics are unsatisfactory. Recently, research on utilizing the accumulation of carriers at the trap levels of semiconductors has been performed. However, the detailed charge/discharge characteristics and principles have not been reported. In this report, we attempted to form new n-type oxide semiconductor/insulator/p-type oxide semiconductor structures. The battery characteristics of these structures were evaluated by charge/discharge measurements. The obtained results clearly indicated the characteristics of rechargeable batteries. Furthermore, the fabricated structure accumulated an approximately 5000 times larger number of carriers than a parallel plate capacitor. Additionally, by constructing circuit models based on the experimental results, the charge/discharge mechanisms were considered. This is the first detailed experimental report on a rechargeable battery that operates without the double injection of ions and electrons.

Cathodic hydrogen charging of zinc

International Nuclear Information System (INIS)

Panagopoulos, C.N.; Georgiou, E.P.; Chaliampalias, D.

2014-01-01

Highlights: •Incorporation of hydrogen into zinc and formation of zinc hydrides. •Investigation of surface residual stresses due to hydrogen diffusion. •Effect of hydrogen diffusion and hydride formation on mechanical properties of Zn. •Hydrogen embrittlement phenomena in zinc. -- Abstract: The effect of cathodic hydrogen charging on the structural and mechanical characteristics of zinc was investigated. Hardening of the surface layers of zinc, due to hydrogen incorporation and possible formation of ZnH 2 , was observed. In addition, the residual stresses brought about by the incorporation of hydrogen atoms into the metallic matrix, were calculated by analyzing the obtained X-ray diffraction patterns. Tensile testing of the as-received and hydrogen charged specimens revealed that the ductility of zinc decreased significantly with increasing hydrogen charging time, for a constant value of charging current density, and with increasing charging current density, for a constant value of charging time. However, the ultimate tensile strength of this material was slightly affected by the hydrogen charging procedure. The cathodically charged zinc exhibited brittle transgranular fracture at the surface layers and ductile intergranular fracture at the deeper layers of the material

Parenting Stress in CHARGE Syndrome and the Relationship with Child Characteristics

NARCIS (Netherlands)

Wulffaert, Josette; Scholte, Evert M.; Dijkxhoorn, Yvette M.; Bergman, Jorieke E. H.; van Ravenswaaij-Arts, Conny M. A.; van Berckelaer-Onnes, Ina A.

This study investigates the parental perception of stress related to the upbringing of children with CHARGE syndrome and its association with behavioral and physical child characteristics. Parents of 22 children completed the Nijmegen Parenting Stress Index-Short, Developmental Behavior Checklist,

Study of test-mass charging process in the LISA missions due to diffuse γ-rays

International Nuclear Information System (INIS)

Finetti, N; Scrimaglio, R; Grimani, C; Fabi, M

2009-01-01

Gravitational inertial sensors will be placed on board the Laser Interferometer Space Antenna (LISA) and aboard its precursor mission LISA Pathfinder (LISA-PF) in order to detect low frequency gravitational waves in space. Free-floating test-masses (Au 7 Pt 3 cubes) will be housed in inertial sensors for detecting possible laser signal variations induced by gravitational waves. Charging of the LISA test-masses due to exposure of the spacecraft to cosmic radiation and energetic solar particles will affect operation of gravitational inertial sensors. In this paper we report on the role of diffuse γ-rays in charging the LISA and LISA-PF test-masses with respect to protons and helium nuclei. The diffuse γ-ray flux in the Galaxy has been interpolated taking into account the outcomes of recent calculations. A comparison with γ-ray observations gathered by different experiments (COMPTEL and EGRET, Milagro, Whipple, HEGRA, TIBET) has been carried out. Simulations of the test-mass charging process have been performed by means of the FLUKA2006.3b package. Monte Carlo simulations of the interaction of cosmic particles with the LISA spacecraft indicate that the diffuse γ-ray contribution to the average steady-state test-mass charging rate and to the single-sided power spectrum of the charge rate noise is marginal with respect to that due to galactic cosmic-rays.

Memory characteristics of silicon nitride with silicon nanocrystals as a charge trapping layer of nonvolatile memory devices

International Nuclear Information System (INIS)

Choi, Sangmoo; Yang, Hyundeok; Chang, Man; Baek, Sungkweon; Hwang, Hyunsang; Jeon, Sanghun; Kim, Juhyung; Kim, Chungwoo

2005-01-01

Silicon nitride with silicon nanocrystals formed by low-energy silicon plasma immersion ion implantation has been investigated as a charge trapping layer of a polycrystalline silicon-oxide-nitride-oxide-silicon-type nonvolatile memory device. Compared with the control sample without silicon nanocrystals, silicon nitride with silicon nanocrystals provides excellent memory characteristics, such as larger width of capacitance-voltage hysteresis, higher program/erase speed, and lower charge loss rate at elevated temperature. These improved memory characteristics are derived by incorporation of silicon nanocrystals into the charge trapping layer as additional accessible charge traps with a deeper effective trap energy level

Large impact of reorganization energy on photovoltaic conversion due to interfacial charge-transfer transitions.

Science.gov (United States)

Fujisawa, Jun-ichi

2015-05-14

Interfacial charge-transfer (ICT) transitions are expected to be a novel charge-separation mechanism for efficient photovoltaic conversion featuring one-step charge separation without energy loss. Photovoltaic conversion due to ICT transitions has been investigated using several TiO2-organic hybrid materials that show organic-to-inorganic ICT transitions in the visible region. In applications of ICT transitions to photovoltaic conversion, there is a significant problem that rapid carrier recombination is caused by organic-inorganic electronic coupling that is necessary for the ICT transitions. In order to solve this problem, in this work, I have theoretically studied light-to-current conversions due to the ICT transitions on the basis of the Marcus theory with density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. An apparent correlation between the reported incident photon-to-current conversion efficiencies (IPCE) and calculated reorganization energies was clearly found, in which the IPCE increases with decreasing the reorganization energy consistent with the Marcus theory in the inverted region. This activation-energy dependence was systematically explained by the equation formulated by the Marcus theory based on a simple excited-state kinetic scheme. This result indicates that the reduction of the reorganization energy can suppress the carrier recombination and enhance the IPCE. The reorganization energy is predominantly governed by the structural change in the chemical-adsorption moiety between the ground and ICT excited states. This work provides crucial knowledge for efficient photovoltaic conversion due to ICT transitions.

A kinetic Monte Carlo model with improved charge injection model for the photocurrent characteristics of organic solar cells

Science.gov (United States)

Kipp, Dylan; Ganesan, Venkat

2013-06-01

We develop a kinetic Monte Carlo model for photocurrent generation in organic solar cells that demonstrates improved agreement with experimental illuminated and dark current-voltage curves. In our model, we introduce a charge injection rate prefactor to correct for the electrode grid-size and electrode charge density biases apparent in the coarse-grained approximation of the electrode as a grid of single occupancy, charge-injecting reservoirs. We use the charge injection rate prefactor to control the portion of dark current attributed to each of four kinds of charge injection. By shifting the dark current between electrode-polymer pairs, we align the injection timescales and expand the applicability of the method to accommodate ohmic energy barriers. We consider the device characteristics of the ITO/PEDOT/PSS:PPDI:PBTT:Al system and demonstrate the manner in which our model captures the device charge densities unique to systems with small injection energy barriers. To elucidate the defining characteristics of our model, we first demonstrate the manner in which charge accumulation and band bending affect the shape and placement of the various current-voltage regimes. We then discuss the influence of various model parameters upon the current-voltage characteristics.

A Temperature Dependent Lumped-charge Model for Trench FS-IGBT

DEFF Research Database (Denmark)

Duan, Yaoqiang; Kang, Yong; Iannuzzo, Francesco

2018-01-01

Abstract: This paper proposes a temperature dependent lumped-charge model for FS-IGBT. Due to the evolution of the IGBT structure, the existing lumped-charge IGBT model established for NPT-IGBT is not suitable for the simulation of FS-IGBT. This paper extends the lumped-charge IGBT model including...... the field-stop (FS) structure and temperature characteristics. The temperature characteristics of the model are considered for both the bipolar part and unipolar part. In addition, a new PN junction model which can distinguish the collector structure is presented and validated by TCAD simulation. Finally...

Electrostatic charge characteristics of jet nebulized aerosols.

Science.gov (United States)

Kwok, Philip Chi Lip; Trietsch, Sebastiaan J; Kumon, Michiko; Chan, Hak-Kim

2010-06-01

Liquid droplets can be spontaneously charged in the absence of applied electric fields by spraying. It has been shown by computational simulation that charges may influence particle deposition in the airways. The electrostatic properties of jet nebulized aerosols and their potential effects on lung deposition have hardly been studied. A modified electrical low pressure impactor (ELPI) was employed to characterize the aerosol charges generated from jet nebulized commercial products. The charge and size measurements were conducted at 50% RH and 22 degrees C with a modified ELPI. Ventolin, Bricanyl, and Atrovent were nebulized using PARI LC Plus jet nebulizers coupled to a DeVilbiss Pulmo-Aide compressor. The aerosols were sampled in 30-sec durations. The drug deposits on the impactor stages were assayed chemically using high-performance liquid chromatography (HPLC). The charges of nebulized deionized water, isotonic saline, and the three commercial products diluted with saline were also measured to analyze the contributions of the major nebule ingredients on charging. No mass assays were performed on these runs. All three commercial nebules generated net negative charges. The magnitude of the charges reduced over the period of nebulization. Ventolin and Bricanyl yielded similar charge profiles. Highly variable charges were produced from deionized water. On the other hand, nebulized saline reproducibly generated net positive charges. Diluted commercial nebules showed charge polarity inversion. The charge profiles of diluted salbutamol and terbutaline solutions resembled those of saline, while the charges from diluted ipratropium solutions fluctuated near neutrality. The charge profiles were shown to be influenced by the concentration and physicochemical properties of the drugs, as well as the history of nebulization. The drugs may have unique isoelectric concentrations in saline at which the nebulized droplets would carry near-zero charges. According to results from

Experimental research on charging characteristics of a solar photovoltaic system by the pressure-control method

Institute of Scientific and Technical Information of China (English)

Hua ZHU; Zhang-lu XU; Zi-juan CAO

2011-01-01

The charging characteristics of the valve-regulated lead acid (VRLA) battery driven by solar energy were experimentally studied through the pressure-control method in this paper. The aims of the research were to increase charging efficiency to make the most of solar energy and to improve charging quality to prolong life of battery. The charging process of a 12 V 12 A.h VRLA battery has been tested under the mode of a stand-alone photovoltaic (PV) system. Results show that the pressure-control method can effectively control PV charging of the VRLA battery and make the best of PV cells through the maximum power point tracking (MPPT). The damage of VRLA battery by excess oxygen accumulation can be avoided through the inner pressure control of VRLA battery. Parameters such as solar radiation intensity, charging power, inner pressure of the battery, and charging current and voltage during the charging process were measured and analyzed.

Practical approach to determining charge collected in multi-junction structures due to the ion shunt effect

International Nuclear Information System (INIS)

Brown, A.O.; Bhuva, B.; Kerns, S.E.

1993-01-01

In order to design semiconductor devices so that they are resistant to single event upsets, a designer needs to know how much charge would be collected at various junctions in the semiconductor structure. For over a decade researchers have studied the physics of charge collection in semiconductor structures, focusing primarily on the charge collected between the p and n regions of a pn junction by drift and diffusion effects -- a process called funneling. However, when an energetic ion penetrates more than one pn junction, funneling is not the only charge collection mechanism. Simulations and experiments on multi-junction structures have shown dramatic change in the charge collected when an ion penetrates two pn junctions. This charge transport between two regions of like conductivity that are ''bridged'' together by the ion track is called the ion shunt effect -- an effect investigated and experimentally proven by Hauser, et al. and Knudson, et al. This paper will present the algorithms and results of a computer program used to determine the charge collected on silicon semiconductor transistors due to the ion shunt effect. The program is unique because it is quick and simple to use and because it uses a general algorithm to determine an accurate initial electron-hole pair distribution in the ion track

Charge characteristics of humic and fulvic acids: comparative analysis by colloid titration and potentiometric titration with continuous pK-distribution function model.

Science.gov (United States)

Bratskaya, S; Golikov, A; Lutsenko, T; Nesterova, O; Dudarchik, V

2008-09-01

Charge characteristics of humic and fulvic acids of a different origin (inshore soils, peat, marine sediments, and soil (lysimetric) waters) were evaluated by means of two alternative methods - colloid titration and potentiometric titration. In order to elucidate possible limitations of the colloid titration as an express method of analysis of low content of humic substances we monitored changes in acid-base properties and charge densities of humic substances with soil depth, fractionation, and origin. We have shown that both factors - strength of acidic groups and molecular weight distribution in humic and fulvic acids - can affect the reliability of colloid titration. Due to deviations from 1:1 stoichiometry in interactions of humic substances with polymeric cationic titrant, the colloid titration can underestimate total acidity (charge density) of humic substances with domination of weak acidic functional groups (pK>6) and high content of the fractions with molecular weight below 1kDa.

Stress distributions due to hydrogen concentrations in electrochemically charged and aged austenitic stainless steel

International Nuclear Information System (INIS)

Rozenak, P.; Loew, A.

2008-01-01

As a result of hydrogen concentration gradients in type austenitic stainless steels, formed during electrochemical charging and followed by hydrogen loss during aging, at room temperature, surface stresses were developed. These stresses were measured by X-ray technique and the crack formation thus induced could be studied using equilibrium stress equations. After various electrochemical charging and aging times, X-ray diffraction patterns obtained from samples indicated that the reflected and broadened diffraction peaks are the result of the formation of a non-uniform but continuous solid solution in the austenitic matrix. Since both hydrogen penetrations during charging and hydrogen release during aging are diffusion controlled processes and huge hydrogen concentration gradients in the thin surface layer, at depths comparable with the depth of X-ray penetration, are observed. The non-uniform hydrogen concentration in the austenitic matrix, results to the non-uniform expansion of the atomic microstructure and latter inevitably leads to the development of internal stresses. The internal stresses development formulae's are very similar to those relating to non-uniform heating of the materials, where thermal stresses appear due to non-uniform expansion or contraction. The relevant well developed theory is applicable in our case of non-uniform hydrogen concentrations in a solid solution of electrochemically charged and aged austenitic matrix. A few cracks were present on the surface after some minutes of electrochemical charging and the severity of cracking increased as hydrogen was lost during subsequent aging. This is consistent with the expectation of high compressive stresses in the bulk of the specimen during charging and high tensile surface stresses (at the level of 1 x 10 11 Pa) during the aging process. These stresses can induce the formation of surface cracks during the aging process after electrochemical charging in the AISI 316 stainless steel

Capacity Decline and Characteristics Changes of Lithium-ion Cells with Large Capacity during Trickle Charge at High Temperature

Science.gov (United States)

Matsushima, Toshio

Large-scale 40-Ah Li-ion cells have been developed for use in industrial applications. To contribute to techniques for ascertaining the state of these cells and detecting deterioration during actual use, we produce a cell whose capacity is reduced by trickle charging at high temperature, and we determine the relationship between the cell's properties such as its capacity and charging/discharging characteristics when the capacity is reduced. When the capacity of a Li-ion cell is reduced, the discharge voltage also decreases. We show that the residual capacity is well correlated to the discharge voltage and to the duration of continuous discharge before reaching a fixed end-voltage. We also show that the constant-current constant-voltage charging characteristics are maintained even when the capacity is degraded, and that the constant-current charging time and discharge voltage are closely related to the residual capacity. We confirm that the reaction coefficient of the capacity degradation formula can be calculated from the capacity change characteristics at multiple temperatures, and that an 8°C change in temperature causes the lifetime to decrease by half.

Non-linear diffusion of charged particles due to stochastic electromagnetic fields

International Nuclear Information System (INIS)

Martins, A.M.; Balescu, R.; Mendonca, J.T.

1989-01-01

It is well known that the energy confinement times observed in tokamak cannot be explained by the classical or neo-classical transport theory. The alternative explanations are based on the existence of various kinds of micro-instabilities, or on the stochastic destruction of the magnetic surfaces, due to the interaction of magnetic islands of different helicities. In the absence of a well established theory of anomalous transport it is perhaps important to study in some detail the diffusion coefficient of single charged particles in the presence of electromagnetic fluctuation, because it can provide the physical grounds for more complete and self-consistent calculations. In the present work we derive a general expression for the transverse diffusion coefficient of electrons and ions in a constant magnetic field and in the presence of space and time dependent electromagnetic fluctuation. We neglect macroscopic drifts due to inhomogeneity and field curvatures, but retain finite Larmor radius effects. (author) 3 refs

Coagulation of dielectric dust grains due to variable asymmetric charging

International Nuclear Information System (INIS)

Manweiler, Jerry W.; Armstrong, Thomas P.; Cravens, Thomas E.

1998-01-01

Observational evidence of electrical forces acting significantly on small solids is present for both the modern solar system in Saturn's rings and the ancient solar system in chondritic meteorites. It is likely that grain-grain coagulation rates are affected by the distribution of charges on small grains. Plasma particle impacts and photoelectric effects can provide the charges. It appears that some charging is inevitable and that plasma grain interactions need to be evaluated to determine the size of the effect on coagulation rates. We apply the results of our previous charging work to models of the protoplanetary nebula. It is expected that the protoplanetary nebula is weakly ionized except in certain instances and locations such as: solar flares in the interior, ultraviolet radiation at the outer boundary, and during enhanced luminosity of the star. Since the grains we study are non-conducting and show strong dipole moments in flowing plasma, we modify the geometric cross sections to include the effects of flowing plasma on non-conducting grains with plasma mediated shielding. This paper provides results showing how plasma flow affects the processes involved in charging the grains--total charge and charge distribution. We calculate the modifications to the cross sections and subsequent changes in the coagulation rates

variability of rainwater quality due to roof characteristics

African Journals Online (AJOL)

water. Although, some people typically consume collected rainwater without any type of ... variability of rain water quality due to roof characteristics was investigated using ... coverage of potable water, water supply still lags ... in getting projects executed; lack of adequate ... deterioration and its effects on health are scarce.

Dynamic Characteristics of Steam Generator Tubes with Defect due to Wear

Energy Technology Data Exchange (ETDEWEB)

Park, Sangjin; Rhee, Huinam [Sunchon National Univ., Sunchon (Korea, Republic of); Yoon, Doo Byung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2013-05-15

These defects may affect the dynamic characteristics of tubes, and therefore, the vibrational behavior of the tube due to flow-induced loads can be varied. Change in the vibrational response of a tube may result in different wear characteristics from the design condition, which must be checked for both safety and economic point of view. This paper deals with the study on the effect of wears or cracks on the dynamic characteristics of steam generator tubes using finite element analysis. In this paper the effect of defects on the surface due to wear on the variation of dynamic characteristics of steam generator tubes was studied using the finite element analysis. The changes of natural frequencies and mode shapes can directly affect the flow-induced vibration response characteristics, therefore, they must be evaluated appropriately. The results in this study can be a good basis to estimate the FIV characteristics of the steam generator tubes having defects such as wear or crack.

Metallicity at interphase boundaries due to polar catastrophe induced by charge density discontinuity

KAUST Repository

Albar, Arwa

2018-02-09

The electronic properties of interphase boundaries are of basic importance for most materials, particularly when those properties deviate strongly from the bulk behavior. We introduce a mechanism that can result in metallicity at stoichiometric interphase boundaries between semiconductors based on the idea of polar catastrophe, which is usually considered only in the context of heterostructures. To this end, we perform ab initio calculations within density functional theory to investigate the electronic states at stoichiometric SnO/SnO2 (110) interphase boundaries. In this system, one would not expect polar catastrophe to have a role according to state-of-the-art theory because the interface lacks formal charge discontinuity. However, we observe the formation of a hole gas between the semiconductors SnO and SnO2. To explain these findings, we provide a generalized theory based on the idea that the charge density discontinuity between SnO and SnO2, a consequence of lattice mismatch, drives a polar catastrophe scenario. As a result, SnO/SnO2 (110) interphase boundaries can develop metallicity depending on the grain size. The concept of metallicity due to polar catastrophe induced by charge density discontinuity is of general validity and applies to many interphase boundaries with lattice mismatch.

Secondary charging effects due to icy dust particle impacts on rocket payloads

Directory of Open Access Journals (Sweden)

M. Kassa

2012-03-01

Full Text Available We report measurements of dust currents obtained with a small probe and a larger probe during the flight of the ECOMA-4 rocket through the summer polar mesosphere. The payload included two small dust probes behind a larger dust probe located centrally at the front. For certain phases of the payload rotation, the current registered by one of the small dust probes was up to 2 times the current measured with the larger probe, even though the effective collection area of the larger probe was 4 times that of the small one. We analyze the phase dependence of the currents and their difference with a model based on the assumption that the small probe was hit by charged dust fragments produced in collisions of mesospheric dust with the payload body. Our results confirm earlier findings that secondary charge production in the collision of a noctilucent cloud/Polar Summer Mesospheric Echo (NLC/PMSE dust particle with the payload body must be several orders of magnitude larger than might be expected from laboratory studies of collisions of pure ice particles with a variety of clean surfaces. An important consequence is that for some payload configurations, one should not assume that the current measured with a detector used to study mesospheric dust is simply proportional to the number density of ambient dust particles. The higher secondary charge production may be due to the NLC/PMSE particles containing multiple meteoric smoke particles.

Alterations in ambipolar characteristic of graphene due to adsorption of Escherichia coli bacteria

Science.gov (United States)

Mulyana, Yana; Uenuma, Mutsunori; Okamoto, Naofumi; Ishikawa, Yasuaki; Yamashita, Ichiro; Uraoka, Yukiharu

2018-03-01

In order to evaluate the interaction between biomaterials and graphene from the perspective of its ambipolar characteristic, we have investigated the alteration in ambipolarity of graphene-based field effect transistors (G-FET) after the adsorption of Escherichia coli (E. coli) bacteria onto its graphene layer. We confirmed a positive shift in the ambipolar curve of the G-FETs after the adsorption of E. coli, presumably due to the negative charge of the adsorbed E. coli. However, we did not observe any decrease in the electron mobility or conductivity of the G-FETs, which implied that E. coli did not chemically react with the carbon atoms of graphene, nor introduce any damage on the graphene lattice, but were only physically adsorbed onto the graphene surface. These findings may extend the prominence of graphene as a stable yet sensitive material to be fully utilized in future biosensing applications. These results were then compared to those of ferritin adsorption, which is a protein shell and biomaterial like E. coli, and radical oxygen doping onto the graphene surface.

Photoemission Experiments for Charge Characteristics of Individual Dust Grains

Science.gov (United States)

Abbas, M. M.; Spann, James F., Jr.; Craven, Paul D.; West, E.; Pratico, Jared; Scheianu, D.; Tankosic, D.; Venturini, C. C.; Whitaker, Ann F. (Technical Monitor)

2001-01-01

Photoemission experiments with UV radiation have been performed to investigate the microphysics and charge characteristics of individual isolated dust grains of various compositions and sizes by using the electrodynamic balance facility at NASA Marshall Space Flight Center. Dust particles of 1 - 100 micrometer diameter are levitated in a vacuum chamber at pressures approx. 10(exp -5) torr and exposed to a collimated beam of UV radiation in the 120-300 nanometers spectral range from a deuterium lamp source with a MgF2 window. A monochromator is used to select the UV radiation wavelength with a spectral resolution of 8 nanometers. The electrodynamic facility permits measurements of the charge and diameters of particles of known composition, and monitoring of photoemission rates with the incident UV radiation. Experiments have been conducted on Al2O3 and silicate particles, and in particular on JSC-1 Mars regolith simulants, to determine the photoelectron yields and surface equilibrium potentials of dust particles when exposed to UV radiation in the 120-250 micrometers spectral range. A brief discussion of the experimental procedure, the results of photoemission experiments, and comparisons with theoretical models will be presented.

Net charge fluctuations and local charge compensation

International Nuclear Information System (INIS)

Fu Jinghua

2006-01-01

We propose net charge fluctuation as a measure of local charge correlation length. It is demonstrated that, in terms of a schematic multiperipheral model, net charge fluctuation satisfies the same Quigg-Thomas relation as satisfied by charge transfer fluctuation. Net charge fluctuations measured in finite rapidity windows depend on both the local charge correlation length and the size of the observation window. When the observation window is larger than the local charge correlation length, the net charge fluctuation only depends on the local charge correlation length, while forward-backward charge fluctuations always have strong dependence on the observation window size. Net charge fluctuations and forward-backward charge fluctuations measured in the present heavy ion experiments show characteristic features similar to those from multiperipheral models. But the data cannot all be understood within this simple model

Characteristics of the fast electron emission produced during the ...

Indian Academy of Sciences (India)

water adsorption and other characteristics of the fast electron emission ..... that the surface charges which leak away when there is adosrbed water on ... implies that it is a measure of the supply of excited species rather than due to the charge.

Effect of surface charge of immortalized mouse cerebral endothelial cell monolayer on transport of charged solutes.

Science.gov (United States)

Yuan, Wei; Li, Guanglei; Gil, Eun Seok; Lowe, Tao Lu; Fu, Bingmei M

2010-04-01

Charge carried by the surface glycocalyx layer (SGL) of the cerebral endothelium has been shown to significantly modulate the permeability of the blood-brain barrier (BBB) to charged solutes in vivo. The cultured monolayer of bEnd3, an immortalized mouse cerebral endothelial cell line, is becoming a popular in vitro BBB model due to its easy growth and maintenance of many BBB characteristics over repeated passages. To test whether the SGL of bEnd3 monolayer carries similar charge as that in the intact BBB and quantify this charge, which can be characterized by the SGL thickness (L(f)) and charge density (C(mf)), we measured the solute permeability of bEnd3 monolayer to neutral solutes and to solutes with similar size but opposite charges: negatively charged alpha-lactalbumin (-11) and positively charged ribonuclease (+3). Combining the measured permeability data with a transport model across the cell monolayer, we predicted the L(f) and the C(mf) of bEnd3 monolayer, which is approximately 160 nm and approximately 25 mEq/L, respectively. We also investigated whether orosomucoid, a plasma glycoprotein modulating the charge of the intact BBB, alters the charge of bEnd3 monolayer. We found that 1 mg/mL orosomucoid would increase SGL charge density of bEnd3 monolayer to approximately 2-fold of its control value.

Annealing effects on the charged particles registration characteristic of the CR-39 traces solid detector

International Nuclear Information System (INIS)

Correa, M.M.

1989-10-01

CR-39 trace solid detectors samples, previously exposed to alpha particles and fission fragments from a Cf-252 source, were submitted to a annealing treatment to study his effects on the characteristics of charged particle traces registration. (L.C.J.A.)

Electrical charging characteristics of the hetero layer film for reducing water-borne paint contamination in electrostatic rotary atomizers

Energy Technology Data Exchange (ETDEWEB)

Yamada, Y.; Imanishi, T.; Yoshida, O.; Mizuno, A. [ABB Japan, Tokyo (Japan)

2010-07-01

The electrostatic rotary atomizer is the most efficient of all liquid spray painting methods. Its use minimizes the waste of paint and reduces emissions of volatile organic compounds (VOCs). Water-borne painting processes which use water-soluble paint also reduce VOC emissions, but the atomizer body is easily contaminated by the paint mists. The Institute of Electrical and Electronics Engineers (IEEE) considered the causes of water-borne paint contamination and presented the experimental results of a contamination proof system in which the atomizer is surrounded by the repelling film that is charged and repels the incoming paint droplets. Among the key factors for repelling film were electrical properties, such as low capacitance and high insulation to keep high surface potential. Charging uniformity was found to be among the most important characteristic to avoid contamination. The pulse electro-acoustic (PEA) method was used to check these features using space charge measurements inside the repelling film. It was concluded that hetero layer films have more uniform charging characteristics than single layer films.

Characteristics of the groups of charged particles in bar pp,pp and K-p interactions at 32 GeV/c

International Nuclear Information System (INIS)

Bogolubsky, M.Yu.; Levitsky, M.S.; Maksimov, V.V.

1995-01-01

In the clan model, a method is developed for determining the following characteristics of the groups of charged particles: group multiplicity in an interval, particle multiplicity in a group, and width distribution of groups. Distribution densities are obtained for particles originating from clans produced at a given rapidity point with given width in bar pp, K - p, and pp interactions at 32 GeV/c. It is shown that the differences in the rate of growth of factorial moments in bar pp and K - p interactions are due to a difference in the relative contributions of small-width clans. 12 refs., 13 figs., 2 tabs

Persistent photoconductivity due to trapping of induced charges in Sn/ZnO thin film based UV photodetector

Science.gov (United States)

Yadav, Harish Kumar; Sreenivas, K.; Gupta, Vinay

2010-05-01

Photoconductivity relaxation in rf magnetron sputtered ZnO thin films integrated with ultrathin tin metal overlayer is investigated. Charge carriers induced at the ZnO-metal interface by the tin metal overlayer compensates the surface lying trap centers and leads to the enhanced photoresponse. On termination of ultraviolet radiation, recombination of the photoexcited electrons with the valence band holes leaves the excess carriers deeply trapped at the recombination center and holds the dark conductivity level at a higher value. Equilibrium between the recombination centers and valence band, due to trapped charges, eventually stimulates the persistent photoconductivity in the Sn/ZnO photodetectors.

Persistent photoconductivity due to trapping of induced charges in Sn/ZnO thin film based UV photodetector

International Nuclear Information System (INIS)

Yadav, Harish Kumar; Sreenivas, K.; Gupta, Vinay

2010-01-01

Photoconductivity relaxation in rf magnetron sputtered ZnO thin films integrated with ultrathin tin metal overlayer is investigated. Charge carriers induced at the ZnO-metal interface by the tin metal overlayer compensates the surface lying trap centers and leads to the enhanced photoresponse. On termination of ultraviolet radiation, recombination of the photoexcited electrons with the valence band holes leaves the excess carriers deeply trapped at the recombination center and holds the dark conductivity level at a higher value. Equilibrium between the recombination centers and valence band, due to trapped charges, eventually stimulates the persistent photoconductivity in the Sn/ZnO photodetectors.

Performance and combustion characteristics of direct-injection stratified-charge rotary engines

Science.gov (United States)

Nguyen, Hung Lee

1987-01-01

Computer simulations of the direct-injection stratified-charge (DISC) Wankel engine have been used to calculate heat release rates and performance and efficiency characteristics of the 1007R engine. Engine pressure data have been used in a heat release analysis to study the effects of heat transfer, leakage, and crevice flows. Predicted engine performance data are compared with experimental test data over a range of engine speeds and loads. An examination of methods to improve the performance of the Wankel engine with faster combustion, reduced leakage, higher compression ratio, and turbocharging is presented.

Construction of Rb charge exchange cell and characteristic experiment for He- ion production

International Nuclear Information System (INIS)

Lee, Hee Seock; Bak, Jun Gyo; Bak, Hae Ill

1991-01-01

The Rb charge exchange cell is constructed as the He - ion source of the SNU 1.5-MV Tandem Van de Graaff accelerator. the characteristic experiments is carried out in order to determine the optimum operational conditions of the cell. The He + ion beam with the energy of 1 - 10 keV, extracted from the duoplasmatron ion source, is passed through the Rb vapor to become He - ions by the two step charge exchange reaction, i.e., He + + Rb → He o* + Rb + and He o* + Rb → He - + Rb + . From the experimental results, it is found that the maximum fractional yield of He - ions is produced at He + /ion energy of 7 keV. The optimum temperatures of the oven and the canal are determined to be 370 deg C and 95 deg C respectively. Under the optimum operational condition the maximum fractional yield of He - ions is 2.42 ± 0.02 5. This charge exchange cell is proved to be an effective system for the production of He - ions. (Author)

Charge dependence and charge asymmetry in the nucleon-nucleon interaction due to processes involving Δ's

International Nuclear Information System (INIS)

Wells, T.B.

1978-01-01

The charge dependence and charge asymmetry of the nucleon-nucleon force arising from the exchange of a pion and a photon with the excitation of a nucleon resonance [Δ(1236)] is calculated. This charge dependence and asymmetry is studied through its effects on the 1 S nucleon-nucleon scattering lengths. The complexity of the calculation forces the use of approximations. The calculation is performed first with a pole approximation for the resonance and a second time with a Chew-Low description of the resonance. Both calculations neglect nuclear recoil. Estimates of this effect are made. The changes in the scattering lengths are small ( +- / 2 = 1.0225 G/sub π 0 / 2 will explain the proton-neutron scattering length

The charge storage characteristics of ZrO2 nanocrystallite-based charge trap nonvolatile memory

International Nuclear Information System (INIS)

Tang Zhen-Jie; Li Rong; Yin Jiang

2013-01-01

ZrO 2 nanocrystallite-based charge trap flash memory capacitors incorporating a (ZrO 2 ) 0.6 (SiO 2 ) 0.4 pseudobinary high-k oxide film as the charge trapping layer were prepared and investigated. The precipitation reaction in the charge trapping layer, forming ZrO 2 nanocrystallites during rapid thermal annealing, was investigated by transmission electron microscopy and X-ray diffraction. It was observed that a ZrO 2 nanocrystallite-based memory capacitor after post-annealing at 850 °C for 60 s exhibits a maximum memory window of about 6.8 V, good endurance and a low charge loss of ∼25% over a period of 10 years (determined by extrapolating the charge loss curve measured experimentally), even at 85 °C. Such 850 °C-annealed memory capacitors appear to be candidates for future nonvolatile flash memory device applications

COSMIC DUST AGGREGATION WITH STOCHASTIC CHARGING

International Nuclear Information System (INIS)

Matthews, Lorin S.; Hyde, Truell W.; Shotorban, Babak

2013-01-01

The coagulation of cosmic dust grains is a fundamental process which takes place in astrophysical environments, such as presolar nebulae and circumstellar and protoplanetary disks. Cosmic dust grains can become charged through interaction with their plasma environment or other processes, and the resultant electrostatic force between dust grains can strongly affect their coagulation rate. Since ions and electrons are collected on the surface of the dust grain at random time intervals, the electrical charge of a dust grain experiences stochastic fluctuations. In this study, a set of stochastic differential equations is developed to model these fluctuations over the surface of an irregularly shaped aggregate. Then, employing the data produced, the influence of the charge fluctuations on the coagulation process and the physical characteristics of the aggregates formed is examined. It is shown that dust with small charges (due to the small size of the dust grains or a tenuous plasma environment) is affected most strongly

Universal Disorder in Organic Semiconductors Due to Fluctuations in Space Charge

Science.gov (United States)

Wu, Tzu-Cheng

This thesis concerns the study of charge transport in organic semiconductors. These materials are widely used as thin-film photoconductors in copiers and laser printers, and for their electroluminescent properties in organic light-emitting diodes. Much contemporary research is directed towards improving the efficiency of organic photovoltaic devices, which is limited to a large extent by the spatial and energetic disorder that hinders the charge mobility. One contribution to energetic disorder arises from the strong Coulomb interactions between injected charges with one another, but to date this has been largely ignored. We present a mean-field model for the effect of mutual interactions between injected charges hopping from site to site in an organic semiconductor. Our starting point is a modified Fröhlich Hamiltonian in which the charge is linearly coupled to the amplitudes of a wide band of dispersionless plasma modes having a Lorentzian distribution of frequencies. We show that in most applications of interest the hopping rates are fast enough while the plasma frequencies are low enough that random thermal fluctuations in the plasma density give rise to an energetically disordered landscape that is effectively stationary for many thousands of hops. Moreover, the distribution of site energies is Gaussian, and the energy-energy correlation function decays inversely with distance; as such, it can be argued that this disorder contributes to the Poole-Frenkel field dependence seen in a wide variety of experiments. Remarkably, the energetic disorder is universal; although it is caused by the fluctuations in the charge density, it is independent of the charge concentration.

Charge collection characteristics of a super-thin diamond membrane detector measured with high-energy heavy ions

International Nuclear Information System (INIS)

Iwamoto, N.; Makino, T.; Onoda, S.; Ohshima, T.; Kamiya, T.; Kada, W.; Skukan, N.; Grilj, V.; Jaksic, M.; Pomorski, M.

2014-01-01

A transmission particle detector based on a super-thin diamond membrane film which can also be used simultaneously as a vacuum window for ion beam extraction has been developed. Charge collection characteristics of a μ-thick diamond membrane detector for high-energy heavy ions including 75 MeV Ne, 150 MeV Ar, 322 MeV Kr, and 454 MeV Xe have been investigated for the first time. Charge collection signals under single particle flux from the thin part are stable and are well distinguishable from background signals. This behavior suggests that the diamond membrane detector could be used for counting single ions. On the other hand, charge collection efficiency is found to decrease with increasing of charge generated in the diamond membrane detector. This suggests that the pulse height defect, which has been previously reported for Si and SiC detectors, also occurs in the diamond membrane detector. (authors)

Analysis of Turbulent Combustion in Simplified Stratified Charge Conditions

Science.gov (United States)

Moriyoshi, Yasuo; Morikawa, Hideaki; Komatsu, Eiji

The stratified charge combustion system has been widely studied due to the significant potentials for low fuel consumption rate and low exhaust gas emissions. The fuel-air mixture formation process in a direct-injection stratified charge engine is influenced by various parameters, such as atomization, evaporation, and in-cylinder gas motion at high temperature and high pressure conditions. It is difficult to observe the in-cylinder phenomena in such conditions and also challenging to analyze the following stratified charge combustion. Therefore, the combustion phenomena in simplified stratified charge conditions aiming to analyze the fundamental stratified charge combustion are examined. That is, an experimental apparatus which can control the mixture distribution and the gas motion at ignition timing was developed, and the effects of turbulence intensity, mixture concentration distribution, and mixture composition on stratified charge combustion were examined. As a result, the effects of fuel, charge stratification, and turbulence on combustion characteristics were clarified.

Emittance growth due to space charge compensation and beam intensity instabilities in negative ion beams

Directory of Open Access Journals (Sweden)

C. A. Valerio-Lizarraga

2018-03-01

Full Text Available The need to extract the maximum beam intensity with low transversal emittance often comes with the drawback of operating the ion source to limits where beam current instabilities arise, such fluctuations can change the beam properties producing a mismatch in the following sections of the machine. The space charge compensation (SCC generated by the beam particles colliding with the residual gas reaches a steady state after a build-up time. This paper shows how once in the steady state, the beam ends with a transversal emittance value bigger than the case without compensation. In addition, we study how the beam intensity variation can disturb the SCC dynamics and its impact on the beam properties. The results presented in this work come from 3-D simulations using tracking codes taking into account the secondary ions to estimate the degree of the emittance growth due to space charge and SCC.

Intrinsic space charge resonances and the space charge limit

International Nuclear Information System (INIS)

Parzen, G.

1990-01-01

A study has been done of the dependence of the space charge limit on the choice of ν-values using a simulation program. This study finds a strong dependence of the space charge limit on the location of the ν-values relative to the intrinsic space charge resonances, which are driven by the space charge forces due to the beam itself. Four accelerators were studied. For some of these accelerators the study suggest that the space charge limit can be increased by about a factor of 2 proper choice of the ν-values. The lower order 1/2 and 1/4 intrinsic resonances appear to be the important resonances. There is some evidence for effects due to the 1/6 and 1/8 intrinsic resonances, particularly for larger synchrotrons. 5 figs

Charge polarization effects and hole spectra characteristics in AlxGa1-xN/GaN superlattices

International Nuclear Information System (INIS)

Assaoui, Fatna; Pereyra, Pedro

2001-10-01

We study the effects of charge polarization on the extended physical properties of superlattices, such as transmission coefficients and valence band structure. We consider both linear and parabolic modulation of the band edge. Based on the theory of finite periodic systems (TFPS), analytic expressions and high precision calculations of the relevant physical quantities for n-cell systems are obtained. New and also well-known features of these systems are identified. Besides the well-known energy bandstructure, we also have the field bandstructure, with interesting characteristics. Wider field gaps at stronger internal electric fields and higher density of field bands for larger layer widths are some of these characteristics. Well defined level density asymmetries identify the minibands induced by charge polarization or the so-called Quantum Confining Stark Effect. We present the n-cell transmission amplitudes, transmission coefficients and miniband structures for different values of the relevant parameters. (author)

Charging and absorption characteristics of small particulates under alternative and electrostatic voltages in an electrostatic precipitator

International Nuclear Information System (INIS)

Jiang Xue-Dong; Xu He; Wang Xin

2014-01-01

The charge quantity of small particulates such as PM2.5 plays a key role in the collection efficiency of an electrostatic precipitator (ESP). Under a single electrostatic voltage, it is difficult to charge and absorb small particulates. A new method of superimposing an alternative voltage on the electrostatic voltage is provided in this paper. Characteristics of small particulates are analyzed under alternative and electrostatic voltages. It is demonstrated that an alternative voltage can significantly improve the collection efficiency in three aspects: preventing anti-corona, increasing the charge quantity of small particulates, and increasing the median particulate size by electric agglomeration. In addition, practical usage with the superposition of alternative voltage is provided, and the results are in agreement with the theoretical analysis. (physics of gases, plasmas, and electric discharges)

Phase transition detection by surface photo charge effect in liquid crystals

Science.gov (United States)

Ivanov, O.; Petrov, M.; Naradikian, H.; Perez-Diaz, J. L.

2018-05-01

The surface photo charge effect (SPCE) was applied for the first time at structure and phase transitions study of hydrogen bonded in dimer liquid crystals (HBDLCs). Due to the high sensitivity of this method, besides first-order phase transitions, characteristic for the p,n-octyloxibenzoic acids (8OBA), an order transition was definitely detected within the nematic range. We state that the SPCE, arising at the solid-HBDLCs interface due to the double electrical layer, is invariably concomitant with solid surface-liquid interfaces, and indicates that the changes of the characteristics of this layer, under incident optical irradiation, induce surface charge rearrangement and alternating potential difference. A mechanism of induction of the SPCE at the interface of solid surface-anisotropic liquids is proposed. We also indicate that this mechanism can be adapted for solid surface-isotropic liquid interface, including colloids (milk) and fog (aerosols)-condensed medium.

Space-charge-mediated anomalous ferroelectric switching in P(VDF-TrEE) polymer films

KAUST Repository

Hu, Weijin

2014-11-12

We report on the switching dynamics of P(VDF-TrEE) copolymer devices and the realization of additional substable ferroelectric states via modulation of the coupling between polarizations and space charges. The space-charge-limited current is revealed to be the dominant leakage mechanism in such organic ferroelectric devices, and electrostatic interactions due to space charges lead to the emergence of anomalous ferroelectric loops. The reliable control of ferroelectric switching in P(VDF-TrEE) copolymers opens doors toward engineering advanced organic memories with tailored switching characteristics.

The impact of nano-coating on surface charge accumulation of epoxy resin insulator: characteristic and mechanism

Science.gov (United States)

Qi, Bo; Gao, Chunjia; Lv, Yuzhen; Li, Chengrong; Tu, Youping; Xiong, Jun

2018-06-01

The flashover phenomenon of the insulator is the main cause for insulating failure of GIS/GIL, and one of the most critical impacting factors is the accumulation of surface charge. The common methods to restrain the surface charge accumulation are reviewed in this paper. Through the reasonable comparison and analysis of these methods, nano-coatings for the insulator were selected as a way to restrain the surface charge accumulation. Based on this, six nano-coated epoxy resin samples with different concentrations of P25-TiO2 nanoparticles were produced. A high precision 3D surface charge measurement system was developed in this paper with a spatial resolution of 4.0 mm2 and a charge resolution of 0.01 µC (m2 · mV)‑1. The experimental results for the epoxy resin sample showed that with the concentration of nanoparticles of the coating material increasing, the surface charge density tended to first decrease and then increase. In the sample coated with 0.5% concentration of nanoparticles, the suppression effect is the optimum, leading to a 63.8% reduction of charge density under DC voltage. The application test for actual nano-coated GIS/GIL basin insulator indicated that the maximum suppression degree for the charge density under DC voltage could reach 48.3%, while it could reach 22.2% for switching impulse voltage and 12.5% for AC context. The control mechanism of nano-coatings on charge accumulation was proposed based on the analysis for surface morphology features and traps characteristics; the shallow traps dominate in the migration of charges while the deep traps operate on the charge accumulation. With the concentration of nanoparticles in nano-coating material mounting up, the density of shallow traps continuously increases, while for deep traps, it first decreases and then increases. For the sample with 0.5% concentration of nanoparticles coated, the competition between shallow traps and deep traps comes to the most balanced state, producing the most

Effect of trap states and microstructure on charge carrier conduction mechanism through semicrystalline poly(vinyl alcohol) granular film

Science.gov (United States)

Das, A. K.; Bhowmik, R. N.; Meikap, A. K.

2018-05-01

We report a comprehensive study on hysteresis behaviour of current-voltage characteristic and impedance spectroscopy of granular semicrystalline poly(vinyl alcohol) (PVA) film. The charge carrier conduction mechanism and charge traps of granular PVA film by measuring and analyzing the temperature dependent current-voltage characteristic indicate a bi-stable electronic state in the film. A sharp transformation of charge carrier conduction mechanism from Poole-Frenkel emission to space charge limited current mechanism has been observed. An anomalous oscillatory behaviour of current has been observed due to electric pulse effect on the molecular chain of the polymer. Effect of microstructure on charge transport mechanism has been investigated from impedance spectroscopy analysis. An equivalent circuit model has been proposed to explain the result.

Charging-delay effect on longitudinal dust acoustic shock wave in strongly coupled dusty plasma

International Nuclear Information System (INIS)

Ghosh, Samiran; Gupta, M.R.

2005-01-01

Taking into account the charging-delay effect, the nonlinear propagation characteristics of longitudinal dust acoustic wave in strongly coupled collisional dusty plasma described by generalized hydrodynamic model have been investigated. In the 'hydrodynamic limit', a Korteweg-de Vries Burger (KdVB) equation with a damping term arising due to dust-neutral collision is derived in which the Burger term is proportional to the dissipation due to dust viscosity through dust-dust correlation and charging-delay-induced anomalous dissipation. On the other hand, in the 'kinetic limit', a KdVB equation with a damping term and a nonlocal nonlinear forcing term arising due to memory-dependent strong correlation effect of dust fluid is derived in which the Burger term depends only on the charging-delay-induced dissipation. Numerical solution of integrodifferential equations reveals that (i) dissipation due to dust viscosity and principally due to charging delay causes excitation of the longitudinal dust acoustic shock wave in strongly coupled dusty plasma and (ii) dust-neutral collision does not appear to play any direct role in shock formation. The condition for the generation of shock is also discussed briefly

Defect states and charge trapping characteristics of HfO2 films for high performance nonvolatile memory applications

International Nuclear Information System (INIS)

Zhang, Y.; Shao, Y. Y.; Lu, X. B.; Zeng, M.; Zhang, Z.; Gao, X. S.; Zhang, X. J.; Liu, J.-M.; Dai, J. Y.

2014-01-01

In this work, we present significant charge trapping memory effects of the metal-hafnium oxide-SiO 2 -Si (MHOS) structure. The devices based on 800 °C annealed HfO 2 film exhibit a large memory window of ∼5.1 V under ±10 V sweeping voltages and excellent charge retention properties with only small charge loss of ∼2.6% after more than 10 4  s retention. The outstanding memory characteristics are attributed to the high density of deep defect states in HfO 2 films. We investigated the defect states in the HfO 2 films by photoluminescence and photoluminescence excitation measurements and found that the defect states distributed in deep energy levels ranging from 1.1 eV to 2.9 eV below the conduction band. Our work provides further insights for the charge trapping mechanisms of the HfO 2 based MHOS devices.

Modelling of electric tree progression due to space charge modified fields

International Nuclear Information System (INIS)

Seralathan, K E; Mahajan, A; Gupta, Nandini

2008-01-01

Tree initiation and growth require localized field enhancement that results in material erosion and formation of tree channels. Tree progression is linked to partial discharges within the tree tubules, characterized by recurrent periods of activity followed by quiescent states. Charge builds up across the non-conducting tree channels during the inactive regime, and discharge follows. In this work, the role of the space charge modified field during the non-discharging regime in deciding the site of subsequent discharges and thereby shaping tree structures is studied. A simple stochastic model was developed, in order to understand the respective effects of charges trapped on the walls of tree tubules, at channel tips, or in the volume of the dielectric. While some charge distributions are seen to arrest tree growth, others encourage axial growth towards the other electrode, and some aid in producing bushy trees clustered around the needle tip. The effect of carbon deposition within tree channels, making them effectively conducting, was also investigated. The insights gained from the simulations were successfully used to explain tree growth in the laboratory under high- and low-field conditions

Space charge in nanostructure resonances

Science.gov (United States)

Price, Peter J.

1996-10-01

In quantum ballistic propagation of electrons through a variety of nanostructures, resonance in the energy-dependent transmission and reflection probabilities generically is associated with (1) a quasi-level with a decay lifetime, and (2) a bulge in electron density within the structure. It can be shown that, to a good approximation, a simple formula in all cases connects the density of states for the latter to the energy dependence of the phase angles of the eigen values of the S-matrix governing the propagation. For both the Lorentzian resonances (normal or inverted) and for the Fano-type resonances, as a consequence of this eigen value formula, the space charge due to filled states over the energy range of a resonance is just equal (for each spin state) to one electron charge. The Coulomb interaction within this space charge is known to 'distort' the electrical characteristics of resonant nanostructures. In these systems, however, the exchange effect should effectively cancel the interaction between states with parallel spins, leaving only the anti-parallel spin contribution.

Marginally bound resonances of charged massive scalar fields in the background of a charged reflecting shell

Energy Technology Data Exchange (ETDEWEB)

Hod, Shahar, E-mail: shaharhod@gmail.com [The Ruppin Academic Center, Emeq Hefer 40250 (Israel); The Hadassah Academic College, Jerusalem 91010 (Israel)

2017-05-10

We study analytically the characteristic resonance spectrum of charged massive scalar fields linearly coupled to a spherically symmetric charged reflecting shell. In particular, we use analytical techniques in order to solve the Klein–Gordon wave equation for the composed charged-shell–charged-massive-scalar-field system. Interestingly, it is proved that the resonant oscillation frequencies of this composed physical system are determined by the characteristic zeroes of the confluent hypergeometric function. Following this observation, we derive a remarkably compact analytical formula for the resonant oscillation frequencies which characterize the marginally-bound charged massive scalar field configurations. The analytically derived resonance spectrum is confirmed by numerical computations.

Polarization transfer in x-ray transitions due to photoionization in highly charged copper-like ions

Science.gov (United States)

Ma, Kun; Chen, Zhan-Bin; Xie, Lu-You; Dong, Chen-Zhong

2018-02-01

Using the density matrix theory and the multi-configuration Dirac-Fock method, the 3{d}3/2 subshell photoionization of highly charged ions is studied, together with their subsequent radiative decay. The effects of polarization transfer on the linear polarization and angular distribution of the 3{d}94{s}2{}2{D}3/2\\to 3{d}104p{}2{P}1/2 characteristic line photoemission for selected Cu-like Zn+, Ba27+, {{{W}}}45+, and {{{U}}}63+ ions are investigated. Our results show that the polarization transfer, arising from the originally polarized incident light, may lead to a considerable change in the alignment parameters and the polarization properties of the radiation, the character of which is highly sensitive to the initial photon polarization, yet virtually independent of the photon energy. These characteristics are very similar to those of the electron bremsstrahlung process reported by Märtin et al (2012 Phys. Rev. Lett. 108 264801). The present results are compared with available experimental results and show a good quantitative agreement.

Charge transfer and partial pinning at the contacts as the origin of a double dip in the transfer characteristics of graphene-based field-effect transistors

International Nuclear Information System (INIS)

Di Bartolomeo, Antonio; Giubileo, Filippo; Santandrea, Salvatore; Romeo, Francesco; Citro, Roberta; Schroeder, Thomas; Lupina, Grzegorz

2011-01-01

We discuss the origin of an additional dip other than the charge neutrality point observed in the transfer characteristics of graphene-based field-effect transistors with a Si/SiO 2 substrate used as the back-gate. The double dip is proved to arise from charge transfer between the graphene and the metal electrodes, while charge storage at the graphene/SiO 2 interface can make it more evident. Considering a different Fermi energy from the neutrality point along the channel and partial charge pinning at the contacts, we propose a model which explains all the features observed in the gate voltage loops. We finally show that the double dip enhanced hysteresis in the transfer characteristics can be exploited to realize graphene-based memory devices.

Dose errors due to charge storage in electron irradiated plastic phantoms

International Nuclear Information System (INIS)

Galbraith, D.M.; Rawlinson, J.A.; Munro, P.

1984-01-01

Commercial plastics used for radiation dosimetry are good electrical insulators. Used in electron beams, these insulators store charge and produce internal electric fields large enough to measurably alter the electron dose distribution in the plastic. The reading per monitor unit from a cylindrical ion chamber imbedded in a polymethylmethacrylate (PMMA) or polystyrene phantom will increase with accumulated electron dose, the increase being detectable after about 20 Gy of 6-MeV electrons. The magnitude of the effect also depends on the type of the plastic, the thickness of the plastic, the wall thickness of the detector, the diameter and depth of the hole in the plastic, the energy of the electron beam, and the dose rate used. Effects of charge buildup have been documented elsewhere for very low energy electrons at extremely high doses and dose rates. Here we draw attention to the charging effects in plastics at the dose levels encountered in therapy dosimetry where ion chamber or other dosimeter readings may easily increase by 5% to 10% and where a phantom, once charged, will also affect subsequent readings taken in 60 Co beams and high-energy electron and x-ray beams for periods of several days to many months. It is recommended that conducting plastic phantoms replace PMMA and polystyrene phantoms in radiation dosimetry

Electron-beam-charged dielectrics: Internal charge distribution

Science.gov (United States)

Beers, B. L.; Pine, V. W.

1981-01-01

Theoretical calculations of an electron transport model of the charging of dielectrics due to electron bombardment are compared to measurements of internal charge distributions. The emphasis is on the distribution of Teflon. The position of the charge centroid as a function of time is not monotonic. It first moves deeper into the material and then moves back near to the surface. In most time regimes of interest, the charge distribution is not unimodal, but instead has two peaks. The location of the centroid near saturation is a function of the incident current density. While the qualitative comparison of theory and experiment are reasonable, quantitative comparison shows discrepancies of as much as a factor of two.

Charged plate in asymmetric electrolytes: One-loop renormalization of surface charge density and Debye length due to ionic correlations.

Science.gov (United States)

Ding, Mingnan; Lu, Bing-Sui; Xing, Xiangjun

2016-10-01

Self-consistent field theory (SCFT) is used to study the mean potential near a charged plate inside a m:-n electrolyte. A perturbation series is developed in terms of g=4πκb, where band1/κ are Bjerrum length and bare Debye length, respectively. To the zeroth order, we obtain the nonlinear Poisson-Boltzmann theory. For asymmetric electrolytes (m≠n), the first order (one-loop) correction to mean potential contains a secular term, which indicates the breakdown of the regular perturbation method. Using a renormalizaton group transformation, we remove the secular term and obtain a globally well-behaved one-loop approximation with a renormalized Debye length and a renormalized surface charge density. Furthermore, we find that if the counterions are multivalent, the surface charge density is renormalized substantially downwards and may undergo a change of sign, if the bare surface charge density is sufficiently large. Our results agrees with large MC simulation even when the density of electrolytes is relatively high.

Radiation-enhanced short channel effects due to multi-dimensional influence from charge at trench isolation oxides

International Nuclear Information System (INIS)

Youk, G.U.; Khare, P.S.; Schrimpf, R.D.; Massengill, L.W.; Galloway, K.F.

1999-01-01

Radiation enhanced drain induced barrier lowering (DIBL) was experimentally observed and verified by 3-D simulations for submicron devices with trench isolation oxides. Submicron MOSFETs with shallow trench isolation were exposed to total-ionizing-dose radiation. Prior to irradiation, the devices exhibited near-ideal current-voltage characteristics, with no significant short-channel effects for as-drawn gate lengths of 0.4 microm. Following irradiation, the off-state leakage current increased significantly for total doses above about 650 krad(SiO 2 ). In addition, the irradiated devices exhibited DIBL that increased the drain current by 5--10x for a gate length of 0.4 microm (the nominal minimum gate length for this process) and much more for slightly shorter devices (0.35 microm). The increase in the off-state leakage current and the accompanying DIBL are shown to be associated with a parasitic field-effect transistor that is present at the edge of the shallow trench. Three-dimensional simulations are used to illustrate the effect. Simulations show that trapped charge at the trench sidewalls enhance the DIBL by depleting the edges of the channel. Radiation-induced charge may decrease the effectiveness of short-channel engineering

Space Charge Effects

CERN Document Server

Ferrario, M.; Palumbo, L.

2014-12-19

The space charge forces are those generated directly by the charge distribution, with the inclusion of the image charges and currents due to the interaction of the beam with a perfectly conducting smooth pipe. Space charge forces are responsible for several unwanted phenomena related to beam dynamics, such as energy loss, shift of the synchronous phase and frequency , shift of the betatron frequencies, and instabilities. We will discuss in this lecture the main feature of space charge effects in high-energy storage rings as well as in low-energy linacs and transport lines.

Planned studies of charge collection in non-uniformly irradiated Si and GaAs detectors

International Nuclear Information System (INIS)

Rosenfeld, A.; Reinhard, M.; Carolan, M.; Kaplan, G.; Lerch, M.; Alexiev, D.

1995-01-01

The aim of this project is to study the time and amplitude characteristics of silicon ion-implanted detectors non-uniformly irradiated with fast neutrons in order to predict their radiation behaviour in the LHC and space. It is expected in such detectors increases of the charge deficit due to trapping by large scale traps and transient time increases due to the reduction of the mobility. The theoretical model will be modified to describe the charge kinetics in the electrical field of the detector created by a non uniform space charge distribution. Experimental confirmation techniques are needed to develop non uniform predictable damage of silicon detectors using fast neutron sources (accelerators, reactors) and to study peculiarities of the charge transport in different parts of the detector. In parallel to experimental research will be started the theoretical development of the charge transport model for non-uniform distribution of space charge in the depletion layer (Neff). The model will include the linear distribution of Neff(y) along the detector as well as the change of sign of Neff (conversion from n to p type of silicon) inside the detector

The effect of ionizing radiation on analog characteristics of MOSFET

International Nuclear Information System (INIS)

Ren Diyuan; Yu Xuefeng; Lu Wu; Gao Wenyu; Fan Long; Zhang Guoqiang; Yan Rongliang

1994-01-01

The effects of 60 Co γ-ray on the linearity and output characteristics of MOSFETs were investigated. The relations of oxide-trapped charge and Si/SiO 2 interface state density to the decrease of mobility μ-bar and transconductance g m , and the shift of the output curves for both P-MOSFETs and N-MOSFETs were qualitatively described. It was shown that degradation of analog characteristics, for P-MOSFETs, resulted from both oxide-trapped charge and interface state, but the degradation for N-MOSFETs was mainly due to the increase of radiation induced Si-SiO 2 interface state density

Charge effects controlling the current hysteresis and negative differential resistance in periodical nanosize Si/CaF sub 2 structures

CERN Document Server

Berashevich, Y A; Kholod, A N; Borisenko, V E

2002-01-01

A kinetic model of charge carrier transport in nanosize periodical Si/CaF sub 2 structures via localized states in dielectric is proposed. Computer simulation of the current-voltage characteristics of such structures has shown that the built-in field arises in a dielectric due to polarization of the trapped charge by localized centers. This results in current hysteresis and negative differential resistance region at the current-voltage characteristics when the bias polarity is changed. At temperature below 250 K, the portion of negative differential resistance vanishes

Like-charge attraction and opposite-charge decomplexation between polymers and DNA molecules

OpenAIRE

Buyukdagli, Sahin

2016-01-01

We scrutinize the effect of polyvalent ions on polymer-DNA interactions. We extend a recently developed test charge theory to the case of a stiff polymer interacting with a DNA molecule in an electrolyte mixture. The theory accounts for one-loop level electrostatic correlation effects such as the ionic cloud deformation around the strongly charged DNA molecule as well as image-charge forces induced by the low DNA permittivity. Our model can reproduce and explain various characteristics of the...

Calculation of current-voltage characteristics of electron-capture detectors

International Nuclear Information System (INIS)

Hinneburg, D.; Grosse, H.J.; Leonhardt, J.; Popp, P.

1983-01-01

Starting from the law of conservation of charge a stationary one-dimensional non-linear differential equation system is derived, which is applied to the direct-current mode of an electron-capture detector with parallel electrode plates. The theory takes into account space-charge, recombination, and inhomogeneous ionization and it deals with three kinds of charge carriers with different mobilities (positive and negative ions, electrons). Terms due to diffusion and gas-flow losses are excluded. The equations so constructed were programmed to get a means of calculating the charge and field distributions and the current-voltage characteristics as functions of various parameters of the detectors, the attaching gas and the ionization. For two cases the results are given. (author)

Decoherence of coupled Josephson charge qubits due to partially correlated low-frequency noise

International Nuclear Information System (INIS)

Hu, Yong; Zhou, Zheng-Wei; Cai, Jian-Ming; Guo, Guang-Can

2007-01-01

Josephson charge qubits are promising candidates for scalable quantum computing. However, their performances are strongly degraded by decoherence due to low-frequency background noise, typically with a 1/f spectrum. In this paper, we investigate the decoherence process of two Cooper pair boxes (CPBs) coupled via a capacitor. Going beyond the common and uncorrelated noise models and the Bloch-Redfield formalism of previous works, we study the coupled system's quadratic dephasing under the condition of partially correlated noise sources. Based on reported experiments and generally accepted noise mechanisms, we introduce a reasonable assumption for the noise correlation, with which the calculation of multiqubit decoherence can be simplified to a problem on the single-qubit level. For the conventional Gaussian 1/f noise case, our results demonstrate that the quadratic dephasing rates are not very sensitive to the spatial correlation of the noises. Furthermore, we discuss the feasibility and efficiency of dynamical decoupling in the coupled CPBs

Changes in the Expandability, Layer charge, and CEC of Smectitic Clay due to a Illitization

International Nuclear Information System (INIS)

Lee, Jae Owan; Cho, Won Jin

2007-01-01

In a high-level waste(HLW) repository, the major fucntions of the smectitic clay for use as a buffer material are to inhibit the penetration of groundwater and to retard the release of radionuclides from the radioactive wastes to the surrounding environment. However, when the smectite clay is exposed to an elevated temperature due to radioactive decay heat and geochemical conditions for a long time, its physicochemical and mineralogical properties may be degradated and thus lose its barrier functions. It has been known in literature that the degradation of these properties of the smectitic clay occurs by a illitization in which the smectite transforms into illite. Therefore, an understanding of the illitization is essential to evaluate the long-term barrier performance of smectitic clay for the buffer of a HLW repository. This paper will carry out hydrothermal reaction tests with domestic smectitic clay which will be favorably considered for the buffer material of a Korean HLW repository, and investigate changes in the expandibility, layer charge and cation exchange capacity(CEC) of the smectitic clay due to a illitization

Electrokinetic characteristics fused quartz in solutions of 1:1, 2:1 and 3:1 charge electrolytes

International Nuclear Information System (INIS)

Bogdanova, N.F.; Sidorova, M.P.; Ermakova, L.Eh.; Savina, I.A.

1997-01-01

Electrokinetic characteristics of silicon oxide have been studied using a model system - a plane-parallel capillary in chloride solutions containing mono-(H + , Na + , Cs + ), two-(Ba 2+ ) and three-(La 3+ ) charge counterions in a wide range of pH and concentrations. It has been revealed that isoelectric point (IEP) of silicon oxide studied coincides with the one usually quoted in literature and corresponds to pH2 in the absence of specific adsorption. Specific adsorption of cesium ions resulting in IEP displacement to pH 3.3 at the back-ground of 0.1M CsCl solution has been detected. Specific adsorption of lanthanum ions increases with increase in the surface charge, involving appearance of a positive electrokinetic potential range at pH>3.3 at the background of 0.1g-eq/l LaCl 3 solution

Rapid charging of nickel-cadmium accumulators

Energy Technology Data Exchange (ETDEWEB)

Bruck, F

1972-01-01

Four types of charging of gas-tight Ni-Cd accumulators (a) normal; (b) accelerated; (c) rapid; and (d) ultra-rapid are described. For rapid charging, a built-in temperature sensor cuts off charging current at a prescribed point. In ultra-rapid charging, 50% charge can be attained in 3.5 min. and 25% charge within 50 sec. In the second phase of ultra-rapid charging, a surplus of oxygen is released at the positive electrode and a safety valve is provided for pressure reduction. Characteristic curves are given for various rates of charging and some data on discharge rates is also given.

Rectified motion in an asymmetrically structured channel due to induced-charge electrokinetic and thermo-kinetic phenomena

International Nuclear Information System (INIS)

Sugioka, Hideyuki

2016-01-01

It would be advantageous to move fluid by the gradient of random thermal noises that are omnipresent in the natural world. To achieve this motion, we propose a rectifier that uses a thermal noise along with induced-charge electroosmosis and electrophoresis (ICEO and ICEP) around a metal post cylinder in an asymmetrically structured channel and numerically examine its rectification performance. By the boundary element method combined with the thin double layer approximation, we find that rectified motion occurs in the asymmetrically structured channel due to ICEO and ICEP. Further, by thermodynamical and equivalent circuit methods, we discuss a thermal voltage that drives a rectifier consisting of a fluidic channel of an electrolyte and an impedance as a noise source. Our calculations show that fluid can be moved in the asymmetrically structured channel by the fluctuation of electric fields due to a thermal noise only when there is a temperature difference. In addition, our simple noise argument provides a different perspective for the thermo-kinetic phenomena (around a metal post) which was predicted based on the electrolyte Seebeck effect in our previous paper [H. Sugioka, “Nonlinear thermokinetic phenomena due to the Seebeck effect,” Langmuir 30, 8621 (2014)

Rectified motion in an asymmetrically structured channel due to induced-charge electrokinetic and thermo-kinetic phenomena

Energy Technology Data Exchange (ETDEWEB)

Sugioka, Hideyuki, E-mail: hsugioka@shinshu-u.ac.jp [Frontier Research Center, Canon Inc. 30-2, Shimomaruko 3-chome, Ohta-ku, Tokyo 146-8501, Japan and Department of Mechanical Systems Engineering, Shinshu University 4-17-1 Wakasato, Nagano 380-8553 (Japan)

2016-02-15

It would be advantageous to move fluid by the gradient of random thermal noises that are omnipresent in the natural world. To achieve this motion, we propose a rectifier that uses a thermal noise along with induced-charge electroosmosis and electrophoresis (ICEO and ICEP) around a metal post cylinder in an asymmetrically structured channel and numerically examine its rectification performance. By the boundary element method combined with the thin double layer approximation, we find that rectified motion occurs in the asymmetrically structured channel due to ICEO and ICEP. Further, by thermodynamical and equivalent circuit methods, we discuss a thermal voltage that drives a rectifier consisting of a fluidic channel of an electrolyte and an impedance as a noise source. Our calculations show that fluid can be moved in the asymmetrically structured channel by the fluctuation of electric fields due to a thermal noise only when there is a temperature difference. In addition, our simple noise argument provides a different perspective for the thermo-kinetic phenomena (around a metal post) which was predicted based on the electrolyte Seebeck effect in our previous paper [H. Sugioka, “Nonlinear thermokinetic phenomena due to the Seebeck effect,” Langmuir 30, 8621 (2014)].

Influence of layer charge and charge distribution of smectites on the flow behaviour and swelling of bentonites

Science.gov (United States)

Christidis, G.E.; Blum, A.E.; Eberl, D.D.

2006-01-01

The influence of layer charge and charge distribution of dioctahedral smectites on the rheological and swelling properties of bentonites is examined. Layer charge and charge distribution were determined by XRD using the LayerCharge program [Christidis, G.E., Eberl, D.D., 2003. Determination of layer charge characteristics of smectites. Clays Clay Miner. 51, 644-655.]. The rheological properties were determined, after sodium exchange using the optimum amount of Na2CO3, from free swelling tests. Rheological properties were determined using 6.42% suspensions according to industrial practice. In smectites with layer charges of - 0.425 to - 0.470 per half formula unit (phfu), layer charge is inversely correlated with free swelling, viscosity, gel strength, yield strength and thixotropic behaviour. In these smectites, the rheological properties are directly associated with the proportion of low charge layers. By contrast, in low charge and high charge smectites there is no systematic relation between layer charge or the proportion of low charge layers and rheological properties. However, low charge smectites yield more viscous suspensions and swell more than high charge smectites. The rheological properties of bentonites also are affected by the proportion of tetrahedral charge (i.e. beidellitic charge), by the existence of fine-grained minerals having clay size, such as opal-CT and to a lesser degree by the ionic strength and the pH of the suspension. A new method for classification of smectites according to the layer charge based on the XRD characteristics of smecites is proposed, that also is consistent with variations in rheological properties. In this classification scheme the term smectites with intermediate layer charge is proposed. ?? 2006 Elsevier B.V. All rights reserved.

Charging System Optimization of Triboelectric Nanogenerator for Water Wave Energy Harvesting and Storage.

Science.gov (United States)

Yao, Yanyan; Jiang, Tao; Zhang, Limin; Chen, Xiangyu; Gao, Zhenliang; Wang, Zhong Lin

2016-08-24

Ocean waves are one of the most promising renewable energy sources for large-scope applications due to the abundant water resources on the earth. Triboelectric nanogenerator (TENG) technology could provide a new strategy for water wave energy harvesting. In this work, we investigated the charging characteristics of utilizing a wavy-structured TENG to charge a capacitor under direct water wave impact and under enclosed ball collision, by combination of theoretical calculations and experimental studies. The analytical equations of the charging characteristics were theoretically derived for the two cases, and they were calculated for various load capacitances, cycle numbers, and structural parameters such as compression deformation depth and ball size or mass. Under the direct water wave impact, the stored energy and maximum energy storage efficiency were found to be controlled by deformation depth, while the stored energy and maximum efficiency can be optimized by the ball size under the enclosed ball collision. Finally, the theoretical results were well verified by the experimental tests. The present work could provide strategies for improving the charging performance of TENGs toward effective water wave energy harvesting and storage.

Study of the degradation of the breakdown voltage of a super-junction power MOSFET due to charge imbalance

International Nuclear Information System (INIS)

Kondekar, Pravin N.; Oh, Hwan-Sool; Kim, Young-Beom

2006-01-01

In this research, we analytically designed a super-junction (SJ) structure and used a simulation tool to study its off-state charge imbalance behavior. In the case of a SJ MOSFET (CoolMOS TM ), designed for the lowest specific on- resistance R on , the MOS part of the transistor (channel region) affected the symmetry, creating a charge imbalance; in addition to this, the imbalance in the SJ drift layer, which was inherently due to limitations in the fabrication process was simulated by varying the doping density of the pillars up to 10 %. The underlying physical mechanisms responsible for the reduction of the breakdown voltage (BV) were investigated in detail by using the electric field profiles and potential contours. The effect of varying the junction depth of a p-body/well and the cell pitch on the breakdown voltage was also analyzed. The trade off between BV sensitivity and specific R on was also investigated.

Insights into the IASB due process: the influence of country characteristics on constituents’ formal participation

Directory of Open Access Journals (Sweden)

Karsten Eisenschmidt

2017-12-01

Full Text Available The paper explores the impact of country characteristics on constituents’ formal participation in the IASB’s due process. We hypothesize that there is an association between the level of constituents’ partic- ipation and (1 the level of economic development, and (2 the cultural characteristics of the country of origin. We use a number of comment letters (CLs and their length as proxies for constituents’ formal participation in the IASB’s due process. The results indicate that economic development (equity market capitalization is the most important explanatory factor for the different levels of participation. In con- trast, the cultural characteristics measured by Hofstede’s cultural framework can only partially explain that differences. Only individualism is a significant positive influence factor for the level of constituents’ participation. The results of our descriptive analysis for the CLs and the information input provided show that there is still a lack of participation in the IASB’s due process. Despite the huge impact of accounting norms on societies, only a limited number of constituents participate, and some constituent groups, like users or academics, participate less.

Charge Transport in Spiro-OMeTAD Investigated through Space-Charge-Limited Current Measurements

Science.gov (United States)

Röhr, Jason A.; Shi, Xingyuan; Haque, Saif A.; Kirchartz, Thomas; Nelson, Jenny

2018-04-01

Extracting charge-carrier mobilities for organic semiconductors from space-charge-limited conduction measurements is complicated in practice by nonideal factors such as trapping in defects and injection barriers. Here, we show that by allowing the bandlike charge-carrier mobility, trap characteristics, injection barrier heights, and the shunt resistance to vary in a multiple-trapping drift-diffusion model, a numerical fit can be obtained to the entire current density-voltage curve from experimental space-charge-limited current measurements on both symmetric and asymmetric 2 ,2',7 ,7' -tetrakis(N ,N -di-4-methoxyphenylamine)-9 ,9' -spirobifluorene (spiro-OMeTAD) single-carrier devices. This approach yields a bandlike mobility that is more than an order of magnitude higher than the effective mobility obtained using analytical approximations, such as the Mott-Gurney law and the moving-electrode equation. It is also shown that where these analytical approximations require a temperature-dependent effective mobility to achieve fits, the numerical model can yield a temperature-, electric-field-, and charge-carrier-density-independent mobility. Finally, we present an analytical model describing trap-limited current flow through a semiconductor in a symmetric single-carrier device. We compare the obtained charge-carrier mobility and trap characteristics from this analytical model to the results from the numerical model, showing excellent agreement. This work shows the importance of accounting for traps and injection barriers explicitly when analyzing current density-voltage curves from space-charge-limited current measurements.

Aberrations due to solenoid focusing of a multiply charged high-current ion beam

CERN Document Server

Grégoire, G; Lisi, N; Schnuriger, J C; Scrivens, R; Tambini, J

2000-01-01

At the output of a laser ion source, a high current of highly charged ions with a large range of charge states is available. The focusing of such a beam by magnetic elements causes a nonlinear space-charge field to develop which can induce large aberrations and emittance growth in the beam. Simulation of the beam from the CERN laser ion source will be presented for an ideal magnetic and electrostatic system using a radially symmetric model. In addition, the three dimensional software KOBRA3 is used for the simulation of the solenoid line. The results of these simulations will be compared with experiments performed on the CERN laser ion source with solenoids (resulting in a hollow beam) and a series of gridded electrostatic lenses. (5 refs).

Reactive Power Support of Electrical Vehicle Charging Station Upgraded with Flywheel Energy Storage System

DEFF Research Database (Denmark)

SUN, BO; Dragicevic, Tomislav; Savaghebi, Mehdi

2015-01-01

Electrical vehicles (EVs) are presenting increasingly potential to replace the conventional fossil fuel based vehicles due to environmental friendly characteristic. Accordingly, Charging Stations (CS), as an intermediate between grid and large numbers of EVs, are supposed to have more critical...... influence on future smart transportation network. This paper explores an off-board charging station upgraded with flywheel energy storage system that could provide a reactive power support to the grid utility. A supervisory control scheme based on distributed bus signaling is proposed to coordinate...... the operation of each component in the system. As a result, the charging station could supply the reactive power support to the utility grid without compromising the charging algorithm and preserve the battery’s lifetime. Finally, the real-time simulation results based on dSPACE1006 verifies the proposed...

Efficient wireless power charging of electric vehicle by modifying the magnetic characteristics of the medium

Science.gov (United States)

Mahmud, Mohammad Hazzaz

There is a developing enthusiasm for electric vehicle (EV) innovations as a result of their lessened fuel utilization and greenhouse emission especially through wireless power transfer (WPT) due to the convenience and continuous charging. Numerous research initiatives target on wireless power transfer (WPT) system in the attempt to improve the transportation for last few decades. But several problems like less efficiency, high frequency, long distance energy transfer etc. were always been occupied by the wireless power transfer system. Two ideas have been developed in this research to resolve the two main problems of WPT for electric vehicles which are low efficiency due to large distance between the two coils and slow charging time. As the first phase of study, a proper model, including the coils and cores were required. The selected model was a finite element (FE) modeling. Another part of this study was to create a modified cement that will act as a semi-conductive material for covering the transmitting antenna area. A high frequency wide band gap switch will be used for transferring high amount of power in a very short time. More over this research also proves that, if cores could be added with the transmitter coil and receiver coil then the output efficiency dramatically increased comparing with without core model of transmitter and receiver. The wireless charging is not restricted to parking lot, since it's planned to be embedded into parking space concrete or roadway concrete or asphalt. Therefore, it can also be installed at junctions (behind red lights), stop signs or any spot that the vehicle might stop for several moments. This technology will become more feasible, if the charging time decreases. Therefore, a new model of for wireless power transfer has been proposed in this study which has shown significant improvement. Another motive of this study was to improve the conductivity and permeability in such a way that the medium that is on the top of the

Photoinduced ultrafast charge-order melting: Charge-order inversion and nonthermal effects

International Nuclear Information System (INIS)

Veenendaal, Michel van

2016-01-01

The effect of photoexcitation is studied for a system with checkerboard charge order induced by displacements of ligands around a metal site. The motion of the ligands is treated classically and the electronic charges are simplified to two-level molecular bond charges. The calculations are done for a checkerboard charge-ordered system with about 100 000 ligand oscillators coupled to a fixed-temperature bath. The initial photoexcitation is followed by a rapid decrease in the charge-order parameter within 50–100 femtoseconds while leaving the correlation length almost unchanged. Depending on the fluence, a complete melting of the charge order occurs in less than a picosecond. While for low fluences, the system returns to its original state, for full melting, it recovers to its broken-symmetry state leading to an inversion of the charge order. Finally, for small long-range interactions, recovery can be slow due to domain formation.

Geometric component of charge pumping current in nMOSFETs due to low-temperature irradiation

Science.gov (United States)

Witczak, S. C.; King, E. E.; Saks, N. S.; Lacoe, R. C.; Shaneyfelt, M. R.; Hash, G. L.; Hjalmarson, H. P.; Mayer, D. C.

2002-12-01

The geometric component of charge pumping current was examined in n-channel metal-oxide-silicon field effect transistors (MOSFETs) following low-temperature irradiation. In addition to the usual dependencies on channel length and gate bias transition time, the geometric component was found to increase with radiation-induced oxide-trapped charge density and decreasing temperature. A postirradiation injection of electrons into the gate oxide reduces the geometric component along with the density of oxide-trapped charge, which clearly demonstrates that the two are correlated. A fit of the injection data to a first-order model for trapping kinetics indicates that the electron trapping occurs predominantly at a single type of Coulomb-attractive trap site. The geometric component results primarily from the bulk recombination of channel electrons that fail to transport to the source or drain during the transition from inversion to accumulation. The radiation response of these transistors suggests that Coulomb scattering by oxide-trapped charge increases the bulk recombination at low temperatures by impeding electron transport. These results imply that the geometric component must be properly accounted for when charge pumping irradiated n-channel MOSFETs at low temperatures.

Interactions Between Charged Macroions Mediated by Molecules with Rod-like Charged Structures

Directory of Open Access Journals (Sweden)

Bohinc, K.

2014-03-01

Full Text Available A short review of recent theoretical advances in studies of the interaction between highly charged systems embedded in a solution of rod-like molecules is presented. The system is theoretically described by the functional density theory, where the correlations within the rod-like molecules are accounted for. We show that for sufficiently long molecules and large surface charge densities, an attractive force between like-charged surfaces arises due to the spatially distributed charges within the molecules. The added salt has an influence on the condition for the attractive force between like-charged surfaces. The theoretical results are compared with Monte Carlo simulations. Many phenomena motivate the study of the interaction between like-charged surfaces (DNA condensation, virus aggregation, yeast flocculation, cohesion of cement paste.

Optimal Charging Schedule Planning and Economic Analysis for Electric Bus Charging Stations

Directory of Open Access Journals (Sweden)

Rong-Ceng Leou

2017-04-01

Full Text Available The battery capacity of electric buses (EB used for public transportation is greater than that of electric cars, and the charging power is also several times greater than that used in electric cars; this can result in high energy consumption and negatively impact power distribution networks. This paper proposes a framework to determine the optimal contracted power capacity and charging schedule of an EB charging station in such a way that energy costs can be reduced. A mathematical model of controlled charging, which includes the capacity and energy charges of the station, was developed to minimize costs. The constraints of the model include the charging characteristics of an EB and the operational guidelines of the bus company. A practical EB charging station was used to verify the proposed model. The financial viability of this EB charging station is also studied in this paper. The economic analysis model for this charging station considers investment and operational costs, and the operational revenue. Sensitivity analyses with respect to some key parameters are also performed in this paper. Based on actual operational routes and EB charging schemes, test results indicate that the EB charging station investment is feasible, and the planning model proposed can be used to determine optimal station power capacity and minimize energy costs.

Neutralization kinetics of charged polymer surface

Energy Technology Data Exchange (ETDEWEB)

Mukherjee, S. [Surface Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India); Mukherjee, M. [Surface Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India)], E-mail: manabendra.mukherjee@saha.ac.in

2008-04-15

In case of photoemission spectroscopy of an insulating material the data obtained from the charged surface are normally distorted due to differential charging. Recently, we have developed a controlled surface neutralization technique to study the kinetics of the surface charging. Using this technique and the associated data analysis scheme with an effective charging model, quantitative information from the apparently distorted photoemission data from PTFE surfaces were extracted. The surface charging was controlled by tuning the electron flood current as well as the X-ray intensity. The effective model was found to describe the charging consistently for both the cases. It was shown that the non-linear neutralization response of differential charging around a critical neutralizing electron flux or a critical X-ray emission current was due to percolation of equipotential surface domains. The obtained value of the critical percolation exponent {gamma} close to unity indicates a percolation similar to that of avalanche breakdown or chain reaction.

Calculation of bulk charge and electric field profiles in one-open-face coaxial γ-detectors using experimental C-U characteristics

International Nuclear Information System (INIS)

Kirnas, I.G.; Litovchenko, P.G.; Petrosyan, E.E.; Pashchuk, N.N.

1987-01-01

Experimental C-U characteristics of one-open-face coaxial detectors are employed in deriving an analytic expression that describes the distributions of ionized impurity bulk charge e(N a - N d ) and electric field E(r) for arbitrary variations of N a - N d in the detector volume. As an example, e(N a - N d ) = f(r) and E(r) are calculated for a Ge(Li)-detector whose experimental C-U characteristics is approximated by a power law with exponent two. (author)

Features of the low-power charge controller of lead-acid current sources charged by solar batteries

International Nuclear Information System (INIS)

Tukfatullin, O.F.; Yuldoshev, I.A.; Solieva, N.A.

2008-01-01

Influence of different factors on exploitations characteristics of solar photoelectric plant is investigated by field-performance data. A construction of charge controller of the lead-acid accumulator battery charging by means of solar battery is analyzed taking into account these factors. (authors)

Organic nonvolatile memory devices with charge trapping multilayer graphene film

International Nuclear Information System (INIS)

Ji, Yongsung; Choe, Minhyeok; Cho, Byungjin; Song, Sunghoon; Yoon, Jongwon; Ko, Heung Cho; Lee, Takhee

2012-01-01

We fabricated an array-type organic nonvolatile memory device with multilayer graphene (MLG) film embedded in polyimide (PI) layers. The memory devices showed a high ON/OFF ratio (over 10 6 ) and a long retention time (over 10 4 s). The switching of the Al/PI/MLG/PI/Al memory devices was due to the presence of the MLG film inserted into the PI layers. The double-log current–voltage characteristics could be explained by the space-charge-limited current conduction based on a charge-trap model. A conductive atomic force microscopy found that the conduction paths in the low-resistance ON state were distributed in a highly localized area, which was associated with a carbon-rich filamentary switching mechanism. (paper)

Genetic syndromes in the family : child characteristics and parenting stress in Angelman, CHARGE, Cornelia de Lange, Prader-Willi, and Rett syndrome

NARCIS (Netherlands)

Wulffaert, Josette

2010-01-01

Aim of the dissertation: To expand the knowledge on the behavioural phenotypes, level of parenting stress and the relationship between child characteristics and parenting stress in five genetic syndromes. The included syndromes are Angelman, CHARGE, Cornelia de Lange, Prader-Willi, and Rett

Charge-coupled devices for particle detection with high spatial resolution

International Nuclear Information System (INIS)

Farley, F.J.; Damerell, C.J.S.; Gillman, A.R.; Wickens, F.J.

1980-10-01

The results of a study of the possible application of a thin microelectronic device (the charge-coupled device) to high energy physics as particle detectors with good spatial resolution which can distinguish between tracks emerging from the primary vertex and those from secondary vertices due to the decay of short lived particles with higher flavours, are reported. Performance characteristics indicating the spatial resolution, particle discrimination, time resolution, readout time and lifetime of such detectors have been obtained. (U.K.)

Conductivity maximum in a charged colloidal suspension

Energy Technology Data Exchange (ETDEWEB)

Bastea, S

2009-01-27

Molecular dynamics simulations of a charged colloidal suspension in the salt-free regime show that the system exhibits an electrical conductivity maximum as a function of colloid charge. We attribute this behavior to two main competing effects: colloid effective charge saturation due to counterion 'condensation' and diffusion slowdown due to the relaxation effect. In agreement with previous observations, we also find that the effective transported charge is larger than the one determined by the Stern layer and suggest that it corresponds to the boundary fluid layer at the surface of the colloidal particles.

Limitations on plasma acceleration due to synchrotron losses

International Nuclear Information System (INIS)

Barletta, W.A.; Lee, E.P.; Bonifacio, R.; De Salvo, L.

1999-01-01

In this letter we consider the effect of synchrotron radiation losses due to the betatron motion of the electron beam in its self-induced magnetic field in a plasma accelerator taking into account the charge neutralization factor. The most favorable case is where the plasma density is smaller than the beam density. The contrary regime is strongly disfavored by the synchrotron radiation loss for beams with characteristics for TeV energies. In both cases we find that upon increasing the plasma density the synchrotron losses kill the acceleration process, so that there are limitations on the maximum allowable plasma density

Emittance growth due to static and radiative space charge forces in an electron bunch compressor

Science.gov (United States)

Talman, Richard; Malitsky, Nikolay; Stulle, Frank

2009-01-01

-21, MOCOS05, available at http://www.JACoW.org], a code with similar capabilities. For this comparison an appropriately new, 50 MeV, “standard chicane” is introduced. Unlike CSRTrack (which neglects vertical forces) the present simulation shows substantial growth of vertical emittance. But “turning off” vertical forces in the UAL code (to match the CSRTrack treatment) brings the two codes into excellent agreement. (iii) Results are also obtained for 5 GeV electrons passing through a previously introduced “standard chicane” [Coherent Synchrotron Radiation, CSR Workshop, Berlin 2002, http://www.desy.de/csr] [of the sort needed for linear colliders and free electron lasers (FEL’s) currently under design or construction]. Relatively little emittance growth is predicted for typical bunch parameters at such high electron energy. Results are obtained for both round beams and ribbon beams (like those actually needed in practice). Little or no excess emittance growth is found for ribbon bunches compared to round bunches of the same charge and bunch width. The UAL string space charge formulation (like TraFic4 and CSRTrack) avoids the regularization step (subtracting the free-space space charge force) which is required (to remove divergence) in some methods. Also, by avoiding the need to calculate a retarded-time, four-dimensional field history, the computation time needed for realistic bunch evolution calculations is modest. Some theories of bunch dilution, because they ascribe emittance growth entirely to CSR, break down at low energy. In the present treatment, as well as CSR, all free-space Coulomb and magnetic space charge forces (but not image forces), and also the centrifugal space charge force (CSCF) are included. Charge-dependent beam steering due to CSCF, as observed recently by Beutner et al. [B. Beutner , in Proceedings of FEL Conference, BESSY, Berlin, Germany, 2006, MOPPH009], is also investigated.

Emittance growth due to static and radiative space charge forces in an electron bunch compressor

Directory of Open Access Journals (Sweden)

Richard Talman

2009-01-01

2004 FEL Conference, pp. 18–21, MOCOS05, available at http://www.JACoW.org], a code with similar capabilities. For this comparison an appropriately new, 50 MeV, “standard chicane” is introduced. Unlike CSRTrack (which neglects vertical forces the present simulation shows substantial growth of vertical emittance. But “turning off” vertical forces in the UAL code (to match the CSRTrack treatment brings the two codes into excellent agreement. (iii Results are also obtained for 5 GeV electrons passing through a previously introduced “standard chicane” [Coherent Synchrotron Radiation, CSR Workshop, Berlin 2002, http://www.desy.de/csr] [of the sort needed for linear colliders and free electron lasers (FEL’s currently under design or construction]. Relatively little emittance growth is predicted for typical bunch parameters at such high electron energy. Results are obtained for both round beams and ribbon beams (like those actually needed in practice. Little or no excess emittance growth is found for ribbon bunches compared to round bunches of the same charge and bunch width. The UAL string space charge formulation (like TraFic4 and CSRTrack avoids the regularization step (subtracting the free-space space charge force which is required (to remove divergence in some methods. Also, by avoiding the need to calculate a retarded-time, four-dimensional field history, the computation time needed for realistic bunch evolution calculations is modest. Some theories of bunch dilution, because they ascribe emittance growth entirely to CSR, break down at low energy. In the present treatment, as well as CSR, all free-space Coulomb and magnetic space charge forces (but not image forces, and also the centrifugal space charge force (CSCF are included. Charge-dependent beam steering due to CSCF, as observed recently by Beutner et al. [B. Beutner et al., in Proceedings of FEL Conference, BESSY, Berlin, Germany, 2006, MOPPH009], is also investigated.

Azimuthal angle dependence of the charge imbalance from charge conservation effects

Science.gov (United States)

BoŻek, Piotr

2018-03-01

The experimental search for the chiral magnetic effect in heavy-ion collisions is based on charge-dependent correlations between emitted particles. Recently, a sensitive observable comparing event-by-event distributions of the charge splitting projected on the directions along and perpendicular to the direction of the elliptic flow has been proposed. The results of a (3 + 1)-dimensional hydrodynamic model show that the preliminary experimental data of the STAR Collaboration can be explained as due to background effects, such as resonance decays and local charge conservation in the particle production. A related observable based on the third-order harmonic flow is proposed to further investigate such background effects in charge-dependent correlations.

The dynamic characteristics of harvesting energy from mechanical vibration via piezoelectric conversion

International Nuclear Information System (INIS)

Fan Kang-Qi; Ming Zheng-Feng; Xu Chun-Hui; Chao Feng-Bo

2013-01-01

As an alternative power solution for low-power devices, harvesting energy from the ambient mechanical vibration has received increasing research interest in recent years. In this paper we study the transient dynamic characteristics of a piezoelectric energy harvesting system including a piezoelectric energy harvester, a bridge rectifier, and a storage capacitor. To accomplish this, this energy harvesting system is modeled, and the charging process of the storage capacitor is investigated by employing the in-phase assumption. The results indicate that the charging voltage across the storage capacitor and the gathered power increase gradually as the charging process proceeds, whereas the charging rate slows down over time as the charging voltage approaches to the peak value of the piezoelectric voltage across the piezoelectric materials. In addition, due to the added electrical damping and the change of the system natural frequency when the charging process is initiated, a sudden drop in the vibration amplitude is observed, which in turn affects the charging rate. However, the vibration amplitude begins to increase as the charging process continues, which is caused by the decrease in the electrical damping (i.e., the decrease in the energy removed from the mechanical vibration). This electromechanical coupling characteristic is also revealed by the variation of the vibration amplitude with the charging voltage. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Space charge effects of CSR

International Nuclear Information System (INIS)

Liu Yong; Xia Jiawen; Xu Xiangyang; Lu Xiaowen; Wu Junli

2000-01-01

Cooler Storage Ring (CSR), and upgrading program planned at the Heavy Ion Research Facility in Lanzhou (HIRFL), will supply beams with higher quality and intensity. Space charge effects should be considered due to this magnitude of intensity in CSR. The concept and some phenomena of space charge effects are discussed. Space charge intensity limit and space charge tune shift of normal CSR operation are given. It is of significance for the construction and operation of the future facility

Simulation of the charging process of the LISA test masses due to solar flares

International Nuclear Information System (INIS)

Vocca, H; Grimani, C; Amico, P; Bosi, L; Marchesoni, F; Punturo, M; Travasso, F; Barone, M; Stanga, R; Vetrano, F; Vicere, A

2004-01-01

Cosmic-ray and solar high energy particles penetrate the LISA experiment test masses. Consequently, an electric charge accumulates in the bodies of the masses, generating spurious Coulomb forces between the masses and the surrounding electrodes. This process increases the noise level of the experiment. We have estimated the amount of charge deposited per second on the LISA test masses by solar flares and primary cosmic-ray protons at solar minimum. The simulation has been carried out with the Fluka Monte Carlo program. A simplified geometry for the experiment has been considered. We have found a net charging rate of 37 ± 1 e + /s for primary protons at solar minimum between 0.1 and 1000 GeV/n. The amount of charge released by a medium-strong solar flare, like that of 16 February 1984, is 10 732 ± 30 e + /s in the energy range 0.1-10 GeV/n. This value increases or decreases by approximately one order of magnitude for strong (weak) solar flares

Analytical calculation of dE/dx cluster-charge loss due to threshold effects

International Nuclear Information System (INIS)

Brady, F.P.; Dunn, J.

1997-01-01

This letter presents a simple analytical approximation which allows one to estimate the effect of ADC threshold on the measured cluster-charge size as used for dE/dx determinations. The idea is to gain some intuitive understanding of the cluster-charge loss and not to replace more accurate simulations. The method is applied to the multiple sampling measurements of energy loss in the main time projection chambers (TPCs) of the NA49 experiment at CERN SPS. The calculations are in reasonable agreement with data. (orig.)

In situ measurement of electrostatic charge and charge distribution on flyash particles in power station exhaust stream

Energy Technology Data Exchange (ETDEWEB)

Guang, D.

1992-01-01

The electrostatic charges and charge distributions on individual flyash particles were experimentally measured in situ at four power stations in New South Wales and in the laboratory with an Electrostatic Charge Classifier. The global charge of these flyashes was also measured. The electrostatic charge on flyash particles of four power stations was found to be globally native. The median charge on the flyash particles varies linearly with particle diameter for all four flyashes. The electrostatic charge on the Tallawarra flyash particles was found to increase after passage through the air heater having huge metal surface areas, suggesting that triboelectrification was the primary charging mechanism for flyash particles. Distinctly different characteristics of the electrostatic charge, particle size and particle shape were found between the Eraring and the Tallawarra flyashes. The spherical Eraring ash has the highest proportion of lines and positively charged particles, but the lowest global charge level among the four flyashes. In contrast, the Tallawarra flyash has just the opposite. It is the distinct characteristics of the flyashes from Eraring and Tallawarra power stations that are responsible for the significant differences in their baghouse performance. The napping feature on the surface of the filter bags used in the Eraring and Tallawarra power stations provides an upstream surface of low fibre density above the fabric bulk. This feature presents and advantage to highly charged particles, like the Tallawarra flyash particles. Highly charged particles tend to deposit on such an upstream surface resulting in a porous dust cake with much less contact areas with the fabric medium than would otherwise be formed. This cake is easy to remove and provides less resistance to the gas flow. After singeing the naps on the filter bag surface at the Eraring power station, the problems of high pressure drop and retention of dust cake on the bas surface have been resolved.

Charging in the environment of large spacecraft

International Nuclear Information System (INIS)

Lai, S.T.

1993-01-01

This paper discusses some potential problems of spacecraft charging as a result of interactions between a large spacecraft, such as the Space Station, and its environment. Induced electric field, due to VXB effect, may be important for large spacecraft at low earth orbits. Differential charging, due to different properties of surface materials, may be significant when the spacecraft is partly in sunshine and partly in shadow. Triple-root potential jump condition may occur because of differential charging. Sudden onset of severe differential charging may occur when an electron or ion beam is emitted from the spacecraft. The beam may partially return to the ''hot spots'' on the spacecraft. Wake effects, due to blocking of ambient ion trajectories, may result in an undesirable negative potential region in the vicinity of a large spacecraft. Outgassing and exhaust may form a significant spacecraft induced environment; ionization may occur. Spacecraft charging and discharging may affect the electronic components on board

The CHARGE Association: Implications for Teachers.

Science.gov (United States)

Jones, Thomas W.; Dunne, Michele T.

1988-01-01

CHARGE association is described as a diagnostic label for a group of congenital malformations, including coloboma, heart defects, atresia choanae, retarded postnatal growth/central nervous system defects, genital hypoplasia, and ear deformities. Etiology and characteristics of the CHARGE association are discussed, along with implications for…

Argon-ion charge distributions following near-threshold ionization

International Nuclear Information System (INIS)

Levin, J.C.

1990-01-01

When an atom is photoionized in an inner shell, there are two mechanisms by which the remaining electron cortege relaxes to fill the vacancy: x-ray emission and radiationless Auger and Coster-Kronig transitions. In the former, the inner-shell hole moves to a less tightly bound orbital without increasing the number of atomic vacancies. In Auger processes, however, the energy liberated by transfer of a less-tightly-bound electron to the inner-shell vacancy is transferred to another electron which is ejected into the continuum. In this case, the charge on the residual ion increases by one. Through a series of radiative and non-radiative processes, the initial vacancy bubbles up until all vacancies arrive at the outermost shell. Due to the many possible routes by which this may occur, there can be a broad distribution of residual ion charge states characteristic of the decay of a single inner-shell vacancy. Because so many processes can contribute to each charge state, it is difficult to determine the effect of each by examining the total ion charge distribution; the total-ion charge distribution represents an average over many effects. To overcome this limitation, the author has recently measured argon-ion production as a function of both photon energy and Auger decay channel following photoionization of K-shell electrons with highly monochromatic synchrotron radiation. When measured differential in decay channel, the ion charge distributions are greatly simplified. Analysis, in progress, of these simplified distributions will permit extraction of information about relative decay rates and shakeoff effects that is obscured in the single spectra

Topology of charge density of flucytosine and related molecules and characteristics of their bond charge distributions.

Science.gov (United States)

Murgich, Juan; Franco, Héctor J; San-Blas, Gioconda

2006-08-24

The molecular charge distribution of flucytosine (4-amino-5-fluoro-2-pyrimidone), uracil, 5-fluorouracil, and thymine was studied by means of density functional theory calculations (DFT). The resulting distributions were analyzed by means of the atoms in molecules (AIM) theory. Bonds were characterized through vectors formed with the charge density value, its Laplacian, and the bond ellipticity calculated at the bond critical point (BCP). Within each set of C=O, C-H, and N-H bonds, these vectors showed little dispersion. C-C bonds formed three different subsets, one with a significant degree of double bonding, a second corresponding to single bonds with a finite ellipticity produced by hyperconjugation, and a third one formed by a pure single bond. In N-C bonds, a decrease in bond length (an increase in double bond character) was not reflected as an increase in their ellipticity, as in all C-C bonds studied. It was also found that substitution influenced the N-C, C-O, and C-C bond ellipticity much more than density and its Laplacian at the BCP. The Laplacian of charge density pointed to the existence of both bonding and nonbonding maxima in the valence shell charge concentration of N, O, and F, while only bonding ones were found for the C atoms. The nonbonding maxima related to the sites for electrophilic attack and H bonding in O and N, while sites of nucleophilic attack were suggested by the holes in the valence shell of the C atoms of the carbonyl groups.

Application of nanoparticle of rock phosphate and biofertilizer in increasing some soil chemical characteristics of variable charge soil

Science.gov (United States)

Devnita, Rina; Joy, Benny; Arifin, Mahfud; Hudaya, Ridha; Oktaviani, Nurul

2018-02-01

Soils in Indonesia are dominated by variable charge soils where the technology like fertilization did not give the same result as the soils with permanent charge. The objectives of this research is to increase some chemical characteristic of variable charge soils by using the high negative charge ameliorations like rock phosphate in nanoparticle combined with biofertilizer. The research used a complete randomized experimental design in factorial with two factors. The first factor was nanoparticle of rock phosphate consists of four doses on soil weight percentage (0%, 2.5%, 5.0% and 7.5%). The second factor was biofertilizer consisted of two doses (without biofertilizer and 1 g.kg-1 soil biofertilizer). The combination treatments replicated three times. Variable charge soil used was Andisol. Andisol and the treatments were incubated for 4 months. Soil samples were taken after one and four months during incubation period to be analyzed for P-retention, available P and potential P. The result showed that all combinations of rock phosphate and biofertilizer decreased the P-retention to 75-77% after one month. Independently, application of 7.5% of rock phosphate decreased P-retention to 87.22% after four months, increased available P (245.37 and 19.12 mg.kg-1) and potential P (1354.78 and 3000.99 mg/100) after one and four months. Independently, biofertilizer increased the P-retention to 91.66% after four months, decreased available P to 121.55 mg.kg-1 after one month but increased to 12.55 mg.kg-1 after four months, decreased potential P to 635.30 after one month but increased to 1810.40 mg.100 g-1 after four months.

On the determination of phosphorus via charged particle activation analysis Pt. 2

International Nuclear Information System (INIS)

Kormali, S.M.; James, W.D.; Poland, J.E.; Schweikert, E.A.

1985-01-01

The application of charged particle activation analysis to the determination of phosphorus in a variety of sample materials is discussed. The activity produced via the sup(31)P(α,n)sup(34m)Cl reaction is quantitated either nondestructively or using postirradiation radiochemical separations depending on the characteristics of the sample matrices. Corrections which are necessary for the determination of phosphorus in pure tantalum metal due to spectral interferences are discussed. (author)

Transport, charge exchange and loss of energetic heavy ions in the earth's radiation belts - Applicability and limitations of theory

Science.gov (United States)

Spjeldvik, W. N.

1981-01-01

Computer simulations of processes which control the relative abundances of ions in the trapping regions of geospace are compared with observations from discriminating ion detectors. Energy losses due to Coulomb collisions between ions and exospheric neutrals are considered, along with charge exchange losses and internal charge exchanges. The time evolution of energetic ion fluxes of equatorially mirroring ions under radial diffusion is modelled to include geomagnetic and geoelectric fluctutations. Limits to the validity of diffusion transport theory are discussed, and the simulation is noted to contain provisions for six ionic charge states and the source effect on the radiation belt oxygen ion distributions. Comparisons are made with ion flux data gathered on Explorer 45 and ISEE-1 spacecraft and results indicate that internal charge exchanges cause the radiation belt ion charge state to be independent of source charge rate characteristics, and relative charge state distribution is independent of the radially diffusive transport rate below the charge state redistribution zone.

A new design approach for enhancement of DC/RF characteristics with improved ambipolar conduction of charge plasma TFET: proposal, and optimization

Science.gov (United States)

Aslam, Mohd.; Sharma, Dheeraj; Yadav, Shivendra; Soni, Deepak; Bajaj, Varun

2018-04-01

This article presents a new device structure to suppress ambipolarity with enhanced electrostatic characteristics of charge plasma TFET (CP-TFET). Here, implantation of a metal angle (MA) of low workfunction inside the high-k dielectric (HfO2) layer near source/channel interface gives excellent improvement in DC and RF characteristics of the proposed device. Deposition of MA is advantageous to increase abruptness of source/channel junction for reducing the tunneling barrier. Along with MA placement, the metal electrode, which is placed over the silicon wafer for inducing N+ drain region, is divided into the two parts of low and high workfunctions. The workfunction of the part of metal electrode near the channel region is taken comparatively higher than the other part to restrict the tunneling of holes at drain/channel junction under negative bias (-V_gs) condition. Such concept induces asymmetrical concentration of charge carriers in the drain region, which widens the tunneling barrier at the drain/channel interface. Consequently, the proposed device shows better RF performance along with suppressed ambipolar conduction. Furthermore, reliability of conventional and proposed structures has been tested in terms of linearity. Simultaneously, the effect of workfunction and length variation of MA on the device characteristics is analyzed in optimization section of the article.

Three-loop charge renormalization effects due to quartic scalar self-interactions

International Nuclear Information System (INIS)

Curtright, T.

1980-01-01

Dimensionally regularized dispersion theory is used to compute the O (h 3 g 3 f 2 ) contribution to the charge renormalization function β/sub g/, where g is a gauge field coupling and f is a quartic (pseudo) scalar self-coupling. Some motivations for and systematics of the calculation are discussed. Special attention is given to an N=4 globally supersymmetric gauge theory

Charge based DC compact modeling of bulk FinFET transistor

Science.gov (United States)

Cerdeira, A.; Garduño, I.; Tinoco, J.; Ritzenthaler, R.; Franco, J.; Togo, M.; Chiarella, T.; Claeys, C.

2013-09-01

Multiple-gate MOSFETs became an industrial reality in the last years. Due to a pragmatic trade-off between CMOS process baselines compatibility, improved performance compared to planar bulk architecture, and cost, bulk FinFETs emerged as the technological solution to provide downscaling for the 14/22 nm technological nodes. In this work, a charge based DC compact model based on the SDDG Model is demonstrated for this new generation of FinFET transistors and describes continuously the transistor characteristics in all operating regions. Validating the model against two bulk FinFET baselines (NMOS, PMOS, various gate lengths and EOT), an excellent agreement is found for transfer and output characteristics (linear and saturation regimes), transconductance/output conductance, and gm/IDS characteristics. Temperature dependence is also taken into account and validated (T range from 25 °C up to 175 °C).

Evolution of perturbation in charge-varying dusty plasmas

International Nuclear Information System (INIS)

Popel, S.I.; Golub, A.P.; Losseva, T.V.; Bingham, R.; Benkadda, S.

2001-01-01

The nonstationary problem of the evolution of perturbation and its transformation into nonlinear wave structure in dusty plasmas is considered. For this purpose two one-dimensional models based on a set of fluid equations, Poisson's equation, and a charging equation for dust are developed. The first (simplified) model corresponds to the case [Popel et al., Phys. Plasmas 3, 4313 (1996)] when exact steady-state shock wave solutions can exist. This simplified model includes variable-charged dust grains, Boltzmann electrons, and inertial ions. The second (ionization source) model takes into account the variation of the ion density and the ion momentum dissipation due to dust particle charging as well as the source of plasma particles due to ionization process. The computational method for solving the set of equations which describe the evolution in time of a nonlinear structure in a charge-varying dusty plasma is developed. The case of the evolution of an intensive initial nonmoving region with a constant enhanced ion density is investigated on the basis of these two models. The consideration within the ionization source model is performed for the data of the laboratory experiment [Luo et al., Phys. Plasmas 6, 3455 (1999)]. It is shown that the ionization source model allows one to obtain shock structures as a result of evolution of an initial perturbation and to explain the experimental value of the width of the shock wave front. Comparison of the numerical data obtained on the basis of the ionization source model and the simplified model shows that the main characteristic features of the shock structure are the same for both models. Nevertheless, the ionization source model is much more sensitive to the form of the initial perturbation than the simplified model. The solution of the problem of the evolution of perturbation and its transformation into shock wave in charge-varying dusty plasmas opens up possibilities for description of the real phenomena like supernova

Scaling of the Coulomb Energy Due to Quantum Fluctuations in the Charge on a Quantum Dot

DEFF Research Database (Denmark)

Molenkamp, L. W; Flensberg, Karsten; Kemerink, M.

1995-01-01

The charging energy of a quantum dot is measured through the effect of its potential on the conductance of a second dot. This technique allows a measurement of the scaling of the dot's charging energy with the conductance of the tunnel barriers leading to the dot. We find that the charging energy...... scales quadratically with the reflection probability of the barriers. The observed power law agrees with a recent theory....

Plasmon excitation in single wall carbon nanotubes by penetrating charged particles

International Nuclear Information System (INIS)

Segui, Silvina; Gervasoni, Juana L; Arista, Néstor R; Mowbray, Duncan J; Mišković, Zoran L

2012-01-01

In this work we study the excitation of plasmons due to the incidence of a charged particle passing through a single wall carbon nanotube. We use a quantized hydrodynamic, in which the σ and π electrons characteristic of these carbonaceous structures are depicted as two interacting 2-dimensional fluids, to calculate the average number of plasmons excited. We analyze the contribution of the different plasmon modes in a variety of configurations, and study the energy lost by the incident particle.

Threshold-Based Random Charging Scheme for Decentralized PEV Charging Operation in a Smart Grid.

Science.gov (United States)

Kwon, Ojin; Kim, Pilkee; Yoon, Yong-Jin

2016-12-26

Smart grids have been introduced to replace conventional power distribution systems without real time monitoring for accommodating the future market penetration of plug-in electric vehicles (PEVs). When a large number of PEVs require simultaneous battery charging, charging coordination techniques have become one of the most critical factors to optimize the PEV charging performance and the conventional distribution system. In this case, considerable computational complexity of a central controller and exchange of real time information among PEVs may occur. To alleviate these problems, a novel threshold-based random charging (TBRC) operation for a decentralized charging system is proposed. Using PEV charging thresholds and random access rates, the PEVs themselves can participate in the charging requests. As PEVs with a high battery state do not transmit the charging requests to the central controller, the complexity of the central controller decreases due to the reduction of the charging requests. In addition, both the charging threshold and the random access rate are statistically calculated based on the average of supply power of the PEV charging system that do not require a real time update. By using the proposed TBRC with a tolerable PEV charging degradation, a 51% reduction of the PEV charging requests is achieved.

Improved speed and data retention characteristics in flash memory using a stacked HfO2/Ta2O5 charge-trapping layer

International Nuclear Information System (INIS)

Zheng, Zhiwei; Huo, Zongliang; Zhang, Manhong; Zhu, Chenxin; Liu, Jing; Liu, Ming

2011-01-01

This paper reports the simultaneous improvements in erase speed and data retention characteristics in flash memory using a stacked HfO 2 /Ta 2 O 5 charge-trapping layer. In comparison to a memory capacitor with a single HfO 2 trapping layer, the erase speed of a memory capacitor with a stacked HfO 2 /Ta 2 O 5 charge-trapping layer is 100 times faster and its memory window is enlarged from 2.7 to 4.8 V for the same ±16 V sweeping voltage range. With the same initial window of ΔV FB = 4 V, the device with a stacked HfO 2 /Ta 2 O 5 charge-trapping layer has a 3.5 V extrapolated 10-year retention window, while the control device with a single HfO 2 trapping layer has only 2.5 V for the extrapolated 10-year window. The present results demonstrate that the device with the stacked HfO 2 /Ta 2 O 5 charge-trapping layer has a strong potential for future high-performance nonvolatile memory application

Deployment Strategy for Charging Piles Based on Distribution Network Capacity Planning and Users’ Needs

Directory of Open Access Journals (Sweden)

Du Chongyang

2015-01-01

Full Text Available Electric vehicles are the most potential transports in the future. However, the large scale of charging facilities will make a great influence on gird. There is a need to make a research on the construction of charging facilities. Based on the power demand characteristics of electric vehicle charging, distribution network capacity, charging system performance and other aspects, this paper mainly researched the deployment strategy of charging piles. First, the authors built up a model with characteristics of charging power demand of electric vehicle and a model of charging service system. The characteristic of daily load curve is analyzed. Second, based on these works, the authors designed the progress of strategy making. At last, the progress was verified by the actual use case.

Conformations of polyelectrolyte macromolecules with different charge density in solutions of different ionic strengths

International Nuclear Information System (INIS)

Dommes, O A; Okatova, O V; Pavlov, G M

2016-01-01

Studies of charged polymer chains are interesting in both fundamental and applied aspects. Especially, polyelectrolytes attract huge attention of researchers due to their ability to form interpolymer complexes with synthetic and biopolymers. The study was carried out on the fractions of hydrophilic copolymers of N-methyl-N-vinyl acetamide and N-methyl-N-vinyl amine hydrochloride of different degrees of polymerization and of different charge density using methods of molecular hydrodynamics. Hydrodynamic and conformational characteristics as well as molar masses of isolated molecules were estimated. In addition, the intrinsic viscosity of fractions was studied at the extreme ionic strengths - in distilled water (∼10 -6 M) and in 6M NaCl. Scaling relations for intrinsic viscosity, sedimentation and translational diffusion coefficients with molar mass were obtained. Conformational behavior of macromolecules with different linear charge density was compared. (paper)

Characteristics of charge coupled devices over X-ray spectral band

Energy Technology Data Exchange (ETDEWEB)

Mishenskij, V O; Volkov, G S; Zajtsev, V I; Zazhivikhin, V V [Troitsk Institute for Thermonuclear and Innovation Investigations (Russian Federation)

1997-12-31

The results of theoretical and experimental investigation of the sensitivity and spatial resolution of charge coupled devices (CCD) influenced by X-ray quanta are reported. Both a calculation model of the interaction process between the X-ray radiation and the CCD-structure and experimental results of investigation of the CCD characteristics are presented. The theoretical model of interaction between X-ray radiation and CCD is suggested. In accordance with the model, the calculations of CCD sensitivity and spatial resolution, depending on the X-ray energy, are performed. The results of comparison of the calculated and experimental data obtained for linear CCD (LCCD) are presented. The CCD has a maximum sensitivity of approx. (1-2.5) . 10{sup 7} V.cm{sup 2}/J for quanta of energies of 0.5-8 keV. The CCD spatial resolution varies from 15-20 {mu}m (CCD gate size) for quanta of energies less then 4 keV and deteriorates up to 150 {mu}m for harder radiation (20-50 keV). CCD usage as space-resolving detectors for high-power installation diagnostics is presented. Other fields of CCD application for X-ray detection are discussed. Advantages of CCD in comparison with the traditional X-ray films is discussed from this point of view. (author). 4 figs., 3 refs.

ON THE POSSIBILITY OF SIGNIFICANT ELECTRON DEPLETION DUE TO NANOGRAIN CHARGING IN THE COMA OF COMET 67P/CHURYUMOV-GERASIMENKO NEAR PERIHELION

Energy Technology Data Exchange (ETDEWEB)

Vigren, E.; Eriksson, A. I.; Wahlund, J.-E. [Swedish Institute of Space physics, Uppsala (Sweden); Galand, M. [Department of Physics, Imperial College London, London (United Kingdom); Lavvas, P., E-mail: erik.vigren@irfu.se [Groupe de Spectrométrie Moléculaire et Atmosphérique, Université Reims Champagne-Ardenne, UMR 7331, F-51687 Reims (France)

2015-01-10

We approach the complicated phenomena of gas-dust interactions in a cometary ionosphere, focusing in particular on the possibility of significant depletion in electron number density due to grain charging. Our one-dimensional ionospheric model, accounting for grain charging processes, is applied to the subsolar direction and the diamagnetic cavity of 67P/Churyuomov-Gerasimenko, the target comet for the ESA Rosetta mission, at perihelion (∼1.25-1.30 AU). We argue on the one hand that grains with radii >100 nm are unlikely to significantly affect the overall ionospheric particle balance within this environment, at least for cometocentric distances >10 km. On the other hand, if nanograins with radii in the 1-3 nm range are ejected to the coma at a level of ∼1% with respect to the mass of the sublimated gas, a significant electron depletion is expected up to cometocentric distances of several tens of kilometers. We relate these results to the recent Cassini discoveries of very pronounced electron depletion compared with the positive ion population in the plume of Enceladus, which has been attributed to nanograin charging.

How good are Hartree-Fock charge densities

International Nuclear Information System (INIS)

Campi, X.

1975-01-01

The principle characteristics of Hartree-Fock charge densities (mean square radius, surface thickness, quantum fluctuation) calculated using different effective interactions are discussed in terms of their nuclear matter properties (Fermi momentum, effective mass, incompressibility). A comparison with the experimental charge distributions is made. Differences between the charge densities of neighbouring nuclei (isotope and isotone shifts) are also considered and the main factors governing these effects are discussed [fr

A Bi-Level Optimization Approach to Charging Load Regulation of Electric Vehicle Fast Charging Stations Based on a Battery Energy Storage System

Directory of Open Access Journals (Sweden)

Yan Bao

2018-01-01

Full Text Available Fast charging stations enable the high-powered rapid recharging of electric vehicles. However, these stations also face challenges due to power fluctuations, high peak loads, and low load factors, affecting the reliable and economic operation of charging stations and distribution networks. This paper introduces a battery energy storage system (BESS for charging load control, which is a more user-friendly approach and is more robust to perturbations. With the goals of peak-shaving, total electricity cost reduction, and minimization of variation in the state-of-charge (SOC range, a BESS-based bi-level optimization strategy for the charging load regulation of fast charging stations is proposed in this paper. At the first level, a day-ahead optimization strategy generates the optimal planned load curve and the deviation band to be used as a reference for ensuring multiple control objectives through linear programming, and even for avoiding control failure caused by insufficient BESS energy. Based on this day-ahead optimal plan, at a second level, real-time rolling optimization converts the control process to a multistage decision-making problem. The predictive control-based real-time rolling optimization strategy in the proposed model was used to achieve the above control objectives and maintain battery life. Finally, through a horizontal comparison of two control approaches in each case study, and a longitudinal comparison of the control robustness against different degrees of load disturbances in three cases, the results indicated that the proposed control strategy was able to significantly improve the charging load characteristics, even with large disturbances. Meanwhile, the proposed approach ensures the least amount of variation in the range of battery SOC and reduces the total electricity cost, which will be of a considerable benefit to station operators.

Motion of charged particles in the magnetosphere

International Nuclear Information System (INIS)

Mukherjee, G.K.; Rajaram, R.

1981-01-01

The adiabatic motion of charged particles in the magnetosphere has been investigated using Mead-Fairfield magnetospheric field model (Mead and Fairfield, 1975). Since the motion of charged particles in a dipolar field geometry is well understood, we bring out in this paper some important features in characteristic motion due to non-dipolar distortions in the field geometry. We look at the tilt averaged picture of the field configuration and estimate theoretically the parameters like bounce period, longitudinal invariant and the bounce averaged drift velocities of the charged particle in the Mead-Fairfield field geometry. These parameters are evaluated as a function of pitch angle and azimuthal position in the region of ring current (5 to 7 Earth radii from the centre of the Earth) for four ranges of magnetic activity. At different longitudes the non-dipolar contribution as a percentage of dipole value in bounce period and longitudinal invariant shows maximum variation for particles close to 90 0 pitch angles. For any low pitch angle, these effects maximize at the midnight meridian. The radial component of the bounce averaged drift velocity is found to be greatest at the dawn-dusk meridians and the contribution vanishes at the day and midnight meridians for all pitch angles. In the absence of tilt-dependent terms in the model, the latitudinal component of the drift velocity vanishes. On the other hand, the relative non-dipolar contribution to bounce averaged azimuthal drift velocity is very high as compared to similar contribution in other characteristic parameters of particle motion. It is also shown that non-dipolar contribution in bounce period, longitudinal invariant and bounce averaged drift velocities increases in magnitude with increase in distance and magnetic activity. (orig.)

Studies on density dependence of charge separation in a direct energy converter using slanted Cusp magnetic field

International Nuclear Information System (INIS)

Munakata, Yoshiro; Kawaguchi, Takashi; Takeno, Hiromasa; Yasaka, Yasuyoshi; Ichimura, Kazuya; Nakashima, Yousuke

2012-01-01

In an advanced fusion, fusion-produced charged particles must be separated from each other for efficient energy conversion to electricity. The CuspDEC performs this function of separation and direct energy conversion. Analysis of working characteristics of CuspDEC on plasma density is an important subject. This paper summarizes and discusses experimental and theoretical works for high density plasma by using a small scale experimental device employing a slanted cusp magnetic field. When the incident plasma is low-density, good separation of the charged particles can be accomplished and this is explained by the theory based on a single particle motion. In high density plasma, however, this theory cannot be always applied due to space charge effects. In the experiment, as gradient of the field line increases, separation capability of the charged particles becomes higher. As plasma density becomes higher, however, separation capability becomes lower. This can be qualitatively explained by using calculations of the modified Störmer potential including space charge potential. (author)

Point charges optimally placed to represent the multipole expansion of charge distributions.

Directory of Open Access Journals (Sweden)

Ramu Anandakrishnan

Full Text Available We propose an approach for approximating electrostatic charge distributions with a small number of point charges to optimally represent the original charge distribution. By construction, the proposed optimal point charge approximation (OPCA retains many of the useful properties of point multipole expansion, including the same far-field asymptotic behavior of the approximate potential. A general framework for numerically computing OPCA, for any given number of approximating charges, is described. We then derive a 2-charge practical point charge approximation, PPCA, which approximates the 2-charge OPCA via closed form analytical expressions, and test the PPCA on a set of charge distributions relevant to biomolecular modeling. We measure the accuracy of the new approximations as the RMS error in the electrostatic potential relative to that produced by the original charge distribution, at a distance 2x the extent of the charge distribution--the mid-field. The error for the 2-charge PPCA is found to be on average 23% smaller than that of optimally placed point dipole approximation, and comparable to that of the point quadrupole approximation. The standard deviation in RMS error for the 2-charge PPCA is 53% lower than that of the optimal point dipole approximation, and comparable to that of the point quadrupole approximation. We also calculate the 3-charge OPCA for representing the gas phase quantum mechanical charge distribution of a water molecule. The electrostatic potential calculated by the 3-charge OPCA for water, in the mid-field (2.8 Å from the oxygen atom, is on average 33.3% more accurate than the potential due to the point multipole expansion up to the octupole order. Compared to a 3 point charge approximation in which the charges are placed on the atom centers, the 3-charge OPCA is seven times more accurate, by RMS error. The maximum error at the oxygen-Na distance (2.23 Å is half that of the point multipole expansion up to the octupole

Impact of charge-transfer excitons in regioregular polythiophene on the charge separation at polythiophene-fullerene heterojunctions

Science.gov (United States)

Polkehn, M.; Tamura, H.; Burghardt, I.

2018-01-01

This study addresses the mechanism of ultrafast charge separation in regioregular oligothiophene-fullerene assemblies representative of poly-3-hexylthiophene (P3HT)-[6,6]-phenyl-C61 butyric acid methyl ester (PCBM) heterojunctions, with special emphasis on the inclusion of charge transfer excitons in the oligothiophene phase. The formation of polaronic inter-chain charge separated species in highly ordered oligothiophene has been demonstrated in recent experiments and could have a significant impact on the net charge transfer to the fullerene acceptor. The present approach combines a first-principles parametrized multi-site Hamiltonian, based on time-dependent density functional theory calculations, with accurate quantum dynamics simulations using the multi-layer multi-configuration time-dependent Hartree method. Quantum dynamical studies are carried out for up to 182 electronic states and 112 phonon modes. The present analysis follows up on our previous study of (Huix-Rotllant et al 2015 J. Phys. Chem. Lett. 6 1702) and significantly expands the scope of this analysis by including the dynamical role of charge transfer excitons. Our investigation highlights the pronounced mixing of photogenerated Frenkel excitons with charge transfer excitons in the oligothiophene domain, and the opening of new transfer channels due the creation of such charge-separated species. As a result, it turns out that the interfacial donor/acceptor charge transfer state can be largely circumvented due to the presence of charge transfer excitons. However, the latter states in turn act as a trap, such that the free carrier yield observed on ultrafast time scales is tangibly reduced. The present analysis underscores the complexity of the transfer pathways at P3HT-PCBM type junctions.

Trends and Patterns in Age Discrimination in Employment Act (ADEA) Charges.

Science.gov (United States)

von Schrader, Sarah; Nazarov, Zafar E

2016-07-01

The Age Discrimination in Employment Act (ADEA) protects individuals aged 40 years and over from discrimination throughout the employment process. Using data on ADEA charges from the Equal Employment Opportunity Commission from 1993 to 2010, we present labor force-adjusted charge rates demonstrating that the highest charge rates are among those in the preretirement age range, and only the rate of charges among those aged 65 years and older has not decreased. We examine characteristics of ADEA charges including the prevalence of different alleged discriminatory actions (or issues) and highlight the increasing proportion of age discrimination charges that are jointly filed with other antidiscrimination statutes. Through a regression analysis, we find that the likelihood of citing various issues differs by charging party characteristics, such as age, gender, and minority status, and on charges that cite only age discrimination as compared to those that are jointly filed. Implications of these findings for employers are discussed. © The Author(s) 2016.

Influence of plug-in hybrid electric vehicle charging strategies on charging and battery degradation costs

International Nuclear Information System (INIS)

Lunz, Benedikt; Yan, Zexiong; Gerschler, Jochen Bernhard; Sauer, Dirk Uwe

2012-01-01

The profitability of plug-in hybrid electric vehicles (PHEVs) is significantly influenced by battery aging and electricity costs. Therefore a simulation model for PHEVs in the distribution grid is presented which allows to compare the influence of different charging strategies on these costs. The simulation is based on real-world driving behavior and European Energy Exchange (EEX) intraday prices for obtaining representative results. The analysis of comprehensive lithium-ion battery aging tests performed within this study shows that especially high battery states of charge (SOCs) decrease battery lifetime, whereas the cycling of batteries at medium SOCs only has a minor contribution to aging. Charging strategies that take into account the previously mentioned effects are introduced, and the SOC distributions and cycle loads of the vehicle battery are investigated. It can be shown that appropriate charging strategies significantly increase battery lifetime and reduce charging costs at the same time. Possible savings due to lifetime extension of the vehicle battery are approximately two times higher than revenues due to energy trading. The findings of this work indicate that car manufacturers and energy/mobility providers have to make efforts for developing intelligent charging strategies to reduce mobility costs and thus foster the introduction of electric mobility. - Highlights: ► Modeling of PHEVs based on real-world driving behavior and electricity prices. ► Consideration of battery degradation for the calculation of mobility costs. ► Smart charging decreases battery degradation and electricity costs simultaneously. ► Reduction of battery degradation costs is around two times higher than reduction of electricity costs.

Charge-imbalance fluctuations in superconductors

International Nuclear Information System (INIS)

Lemberger, T.R.

1981-01-01

We calculate that the mean-square amplitude of the fluctuations of the condensate chemical potential μ/sub s/ due to charge-imbalance fluctuations in the limit Δ/k/sub B/T 2 > = 2(k/sub B/T) 2 /πdeltaΩN(0) in a volume Ω of superconductor. We relate these fluctuations via Nyquist's theorem to measured values of the contribution of self-injected charge imbalance to the dc resistance of SIN tunnel junctions. In this relation the dynamic charge-imbalance relaxation rate is 1/tau/sub E/, the electron-phonon scattering rate

Crossover from band-like to thermally activated charge transport in organic transistors due to strain-induced traps

KAUST Repository

Mei, Yaochuan; Diemer, Peter J.; Niazi, Muhammad Rizwan; Hallani, Rawad K.; Jarolimek, Karol; Day, Cynthia S.; Risko, Chad; Anthony, John E.; Amassian, Aram; Jurchescu, Oana D.

2017-01-01

The temperature dependence of the charge-carrier mobility provides essential insight into the charge transport mechanisms in organic semiconductors. Such knowledge imparts critical understanding of the electrical properties of these materials

Charged black rings at large D

Energy Technology Data Exchange (ETDEWEB)

Chen, Bin [Department of Physics and State Key Laboratory of Nuclear Physics and Technology,Peking University,5 Yiheyuan Rd, Beijing 100871 (China); Collaborative Innovation Center of Quantum Matter,5 Yiheyuan Rd, Beijing 100871 (China); Center for High Energy Physics, Peking University,5 Yiheyuan Rd, Beijing 100871 (China); Li, Peng-Cheng; Wang, Zi-zhi [Department of Physics and State Key Laboratory of Nuclear Physics and Technology,Peking University,5 Yiheyuan Rd, Beijing 100871 (China)

2017-04-28

We study the charged slowly rotating black holes in the Einstein-Maxwell theory in the large dimensions (D). By using the 1/D expansion in the near regions of the black holes we obtain the effective equations for the charged slowly rotating black holes. The effective equations capture the dynamics of various stationary solutions, including the charged black ring, the charged slowly rotating Myers-Perry black hole and the charged slowly boosted black string. Via different embeddings we construct these stationary solutions explicitly. For the charged black ring at large D, we find that the charge lowers the angular momentum due to the regularity condition on the solution. By performing the perturbation analysis of the effective equations, we obtain the quasinormal modes of the charge perturbation and the gravitational perturbation analytically. Like the neutral case the charged thin black ring suffers from the Gregory-Laflamme-like instability under the non-axisymmetric perturbations, but the charge weakens the instability. Besides, we find that the large D analysis always respects the cosmic censorship.

On-line charge breeding using ECRIS and EBIS

Energy Technology Data Exchange (ETDEWEB)

Vondrasek, Richard, E-mail: Vondrasek@anl.gov

2016-06-01

The efficient and rapid production of a high-quality, pure beam of highly charged ions is at the heart of any radioactive ion beam facility. Whether an electron cyclotron resonance (ECR) ion source or an electron beam ion source (EBIS) is used to produce these highly charged ions, their operating characteristics will set the boundaries on the range of experiments which can be performed. In addition, time structure and duty cycle have to be considered when defining the operating parameters of the accelerator system as a whole. At Argonne National Laboratory (ANL), an ECR charge breeder was developed as part of the Californium Rare Ion Breeder Upgrade (CARIBU) program. The charge breeding efficiency and high charge state production of the source is at the forefront of ECR charge breeders, but its overall performance as part of the accelerator system is limited by pervasive background and relatively long breeding times. As such, an EBIS charge breeder has been developed and is running in an off-line configuration. It has already demonstrated good breeding efficiencies, shorter residence times, and reduced background and is scheduled to replace the ECR charge breeder in late 2015. The resultant change in duty cycle and time structure necessitates changes to the overall operation of the facility. The experiences with these breeders, as well as from several other facilities which already utilize an ECR or EBIS for charge breeding, help to define the operational characteristics of each technology – their strengths, their weaknesses, and the possible paths to improvement.

Dependence of the carrier mobility and trapped charge limited conduction on silver nanoparticles embedment in doped polypyrrole nanostructures

Science.gov (United States)

Biswas, Swarup; Dutta, Bula; Bhattacharya, Subhratanu

2013-10-01

The present article demonstrates an intensive study upon the temperature dependent current density (J)-voltage (V) characteristics of moderately doped polypyrrole nanostructure and its silver nanoparticles incorporated nanocomposites. Analysis of the measured J-V characteristics of different synthesized nano-structured samples within a wide temperature range revealed that the electrical conduction behavior followed a trapped charge-limited conduction and a transition of charge transport mechanism from deep exponential trap limited conduction to shallow traps limited conduction had been occurred due to the incorporation of silver nanoparticles within the polypyrrole matrix. A direct evaluation of carrier mobility as a function of electric field and temperature from the measured J-V characteristics illustrates that the incorporation of silver nanoparticles within the polypyrrole matrix enhances the carrier mobility at a large extent by reducing the concentration of traps within the polypyrrole matrix. The calculated mobility is consistent with the Poole-Frenkel form for the electrical field up to a certain temperature range. The nonlinear low temperature dependency of mobility of all the nanostructured samples was explained by Mott variable range hopping conduction mechanisms. Quantitative information regarding the charge transport parameters obtained from the above study would help to extend optimization strategies for the fabrication of new organic semiconducting nano-structured devices.

Metallicity at interphase boundaries due to polar catastrophe induced by charge density discontinuity

KAUST Repository

Albar, Arwa; Tahini, Hassan Ali; Schwingenschlö gl, Udo

2018-01-01

the electronic states at stoichiometric SnO/SnO2 (110) interphase boundaries. In this system, one would not expect polar catastrophe to have a role according to state-of-the-art theory because the interface lacks formal charge discontinuity. However, we observe

Collisional charging of individual submillimeter particles: Using ultrasonic levitation to initiate and track charge transfer

Science.gov (United States)

Lee, Victor; James, Nicole M.; Waitukaitis, Scott R.; Jaeger, Heinrich M.

2018-03-01

Electrostatic charging of insulating fine particles can be responsible for numerous phenomena ranging from lightning in volcanic plumes to dust explosions. However, even basic aspects of how fine particles become charged are still unclear. Studying particle charging is challenging because it usually involves the complexities associated with many-particle collisions. To address these issues, we introduce a method based on acoustic levitation, which makes it possible to initiate sequences of repeated collisions of a single submillimeter particle with a flat plate, and to precisely measure the particle charge in situ after each collision. We show that collisional charge transfer between insulators is dependent on the hydrophobicity of the contacting surfaces. We use glass, which we modify by attaching nonpolar molecules to the particle, the plate, or both. We find that hydrophilic surfaces develop significant positive charges after contacting hydrophobic surfaces. Moreover, we demonstrate that charging between a hydrophilic and a hydrophobic surface is suppressed in an acidic environment and enhanced in a basic one. Application of an electric field during each collision is found to modify the charge transfer, again depending on surface hydrophobicity. We discuss these results within the context of contact charging due to ion transfer, and we show that they lend strong support to O H- ions as the charge carriers.

Characteristics of Charging and Collection of 10-nm-Class Ultrafine Nanoparticles in an Electrostatic Precipitator

International Nuclear Information System (INIS)

Han, Bang Woo; Kim, Hak Joon; Kim, Yong Jin; Song, Dong Keun; Hong, Won Seok; Shin, Wan Ho

2011-01-01

The charging of 10-nm-class nanoparticles in an electrostatic precipitator (ESP) according to particle charging ratio has been investigated and compared to the diffusion effect of the nanoparticles. The competition between the charging probability and the diffusion loss effect determines the collection efficiency of nanoparticles in the ESP. The collection efficiency of nanoparticles decreased continuously with decreasing particle diameter. This indicates that the partial charging effect of 10-nm-class nanoparticles is more dominant than their diffusion loss effect in the ESP for nanoparticles in the particle size range of less than 10 nm. The charging ratios based on unipolar diffusion charging calculations were in good agreement with the experimental collection efficiencies for nanoparticles less than 10 nm in diameter

Space-charge-limit instabilities in electron beams

International Nuclear Information System (INIS)

Coutsias, E.A.; Sullivan, D.J.

1983-01-01

The method of characteristics and multiple-scaling perturbation techniques are used to study the space-charge instability of electron beams. It is found that the stable oscillating state (virtual cathode) created when the space-charge limit is exceeded is similar to a collisionless shock wave. The oscillatory solution originates at the bifurcation point of two unstable steady states. Complementary behavior (virtual anode) results when an ion beam exceeds its space-charge limit. The virtual cathode can also exist in the presence of a neutralizing heavy-ion background. The Pierce instability, where the electron and ion charge densities are equal, is a special case of this broader class. Estimates of the nonlinear growth rate of the instability at the space-charge limit are given

Charge-charge correlations and the detection of weak vector bosons by hadronic jets in proton-antiproton and proton-proton collisions at collider energies

International Nuclear Information System (INIS)

Ranft, J.; Ritter, S.

1980-07-01

The charge properties of quark jets are studied within a chain decay model for quark jet fragmentation. Using the charge properties of quark jets, charge-charge two-jet cross sections and correlations are defined. In proton-antiproton collisions these correlations show significant structure due to the weak vector bosons W +- and Z 0 . (author)

Charging properties of a dust grain in collisional plasmas

International Nuclear Information System (INIS)

Khrapak, S.A.; Morfill, G.E.; Khrapak, A.G.; D'yachkov, L.G.

2006-01-01

Charging related properties of a small spherical grain immersed in a collisional plasma are investigated. Asymptotic expressions for charging fluxes, grain surface potential, long range electrostatic potential, and the properties of grain charge fluctuations due to the discrete nature of the charging process are obtained. These analytical results are in reasonable agreement with the available results of numerical modeling

Injection space charge: enlargements of flux density functioning point choice

International Nuclear Information System (INIS)

Ropert, A.

In Saturne, injection consists of a synchrobetatron filling of the chamber, with the goal of providing a beam with the following characteristics circulating in the machine: horizontal flux density 90 πmm mrd, vertical flux density 210 πmm mrd, dispersion in moments +- 7 x 10 -3 , and number of particles 2 x 10 12 . The determination of the principal injection parameters was made by means of GOC calculation programs. The goal of this study is to show a certain number of phenomena induced by the forces due to space charge and left suspended up to this point: variations in the intensity injectable into the machine extension of the beam occupation zone in the ν/sub x'/ ν/sub z/ diagram, and turn-turn interactions. The effects of the space charge lead to a deterioration of the injected beam for certain functioning points leading to the selection of a zone in the ν/sub x'/ ν/sub z/ diagram that is particularly suitable for beam injection

Irradiation of graphene field effect transistors with highly charged ions

Energy Technology Data Exchange (ETDEWEB)

Ernst, P.; Kozubek, R.; Madauß, L.; Sonntag, J.; Lorke, A.; Schleberger, M., E-mail: marika.schleberger@uni-due.de

2016-09-01

In this work, graphene field-effect transistors are used to detect defects due to irradiation with slow, highly charged ions. In order to avoid contamination effects, a dedicated ultra-high vacuum set up has been designed and installed for the in situ cleaning and electrical characterization of graphene field-effect transistors during irradiation. To investigate the electrical and structural modifications of irradiated graphene field-effect transistors, their transfer characteristics as well as the corresponding Raman spectra are analyzed as a function of ion fluence for two different charge states. The irradiation experiments show a decreasing mobility with increasing fluences. The mobility reduction scales with the potential energy of the ions. In comparison to Raman spectroscopy, the transport properties of graphene show an extremely high sensitivity with respect to ion irradiation: a significant drop of the mobility is observed already at fluences below 15 ions/μm{sup 2}, which is more than one order of magnitude lower than what is required for Raman spectroscopy.

Charge collection and space charge distribution in neutron-irradiated epitaxial silicon detectors

International Nuclear Information System (INIS)

Poehlsen, Thomas

2010-04-01

In this work epitaxial n-type silicon diodes with a thickness of 100 μm and 150 μm are investigated. After neutron irradiation with fluences between 10 14 cm -2 and 4 x 10 15 cm -2 annealing studies were performed. CV-IV curves were taken and the depletion voltage was determined for different annealing times. All investigated diodes with neutron fluences greater than 2 x 10 14 cm -2 showed type inversion due to irradiation. Measurements with the transient current technique (TCT) using a pulsed laser were performed to investigate charge collection effects for temperatures of -40 C, -10 C and 20 C. The charge correction method was used to determine the effective trapping time τ eff . Inconsistencies of the results could be explained by assuming field dependent trapping times. A simulation of charge collection could be used to determine the field dependent trapping time τ eff (E) and the space charge distribution in the detector bulk. Assuming a linear field dependence of the trapping times and a linear space charge distribution the data could be described. Indications of charge multiplication were seen in the irradiated 100 μm thick diodes for all investigated fluences at voltages above 800 V. The space charge distribution extracted from TCT measurements was compared to the results of the CV measurements and showed good agreement. (orig.)

Obliquely propagating cnoidal waves in a magnetized dusty plasma with variable dust charge

International Nuclear Information System (INIS)

Yadav, L. L.; Sayal, V. K.

2009-01-01

We have studied obliquely propagating dust-acoustic nonlinear periodic waves, namely, dust-acoustic cnoidal waves, in a magnetized dusty plasma consisting of electrons, ions, and dust grains with variable dust charge. Using reductive perturbation method and appropriate boundary conditions for nonlinear periodic waves, we have derived Korteweg-de Vries (KdV) equation for the plasma. It is found that the contribution to the dispersion due to the deviation from plasma approximation is dominant for small angles of obliqueness, while for large angles of obliqueness, the dispersion due to magnetic force becomes important. The cnoidal wave solution of the KdV equation is obtained. It is found that the frequency of the cnoidal wave depends on its amplitude. The effects of the magnetic field, the angle of obliqueness, the density of electrons, the dust-charge variation and the ion-temperature on the characteristics of the dust-acoustic cnoidal wave are also discussed. It is found that in the limiting case the cnoidal wave solution reduces to dust-acoustic soliton solution.

Synthesis, characterization and charge transport mechanism of CdZnO nanorods

International Nuclear Information System (INIS)

Mahmoud, Waleed E.; Al-Ghamdi, A.A.; El-Tantawy, F.; Al-Heniti, S.

2009-01-01

ZnO and Cd-doped ZnO nanostructures were prepared by new facile method at 80 deg. C. XRD measurement indicated that both samples had typical hexagonal wurtzite structures. Transmission electron microscopy (TEM) measurement shows that rod-like crystals have been formed. EDX measurement confirms the incorporation of the cadmium ion into the crystalline lattice of ZnO and indicated that cadmium ions uniformly distributed on the surface of the rods. The doping with cadmium ions has a great influence on the optical properties of the ZnO. The electrical measurements of Cd-doped ZnO nanorod were measured. The current-voltage (I-V) characteristic curve revealed that the charge transport above 4 V is mainly non-linear due to grain boundary contribution. The complex impedance spectroscopy was confirmed that the grain boundary effect controls the charge transport mechanism through CdZnO ceramic material.

A numerical study on the charge transport in TPD/Alq3-based organic light emitting diodes.

Science.gov (United States)

Kim, K S; Hwang, Y W; Lee, H G; Won, T Y

2014-08-01

We report our simulation study on the charge transport characteristic of the multi-layer structure for organic light emitting diodes (OLEDs). We performed a numerical simulation on a multilayer structure comprising a hole transport layer (HTL), an emission layer (EML), and an electron transport layer (ETL) between both electrodes. The material of the HTL is TPD (N,N'-Bis (3-methylphenyl)-N,N'-bis(phenyl) benzidine), and the ETL includes Alq3 (Tris (8-hyroxyquinolinato) aluminium). Here, we investigated the parameters such as recombination rates which influence the efficiency of the charge transport between layers in bilayer OLEDs. We also analyzed a transient response during the turn on/off period and the carrier transport in accordance with the variation of the injection barrier and applied voltage. In addition, our numerical simulation revealed that the insertion of the EML affects the photonic characteristics in bilayer structure and also the efficiency due to the difference in the internal barrier height.

Exploring Demand Charge Savings from Commercial Solar

Energy Technology Data Exchange (ETDEWEB)

Darghouth, Naim [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Barbose, Galen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mills, Andrew [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wiser, Ryan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gagnon, Pieter [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bird, Lori [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2017-07-31

Commercial retail electricity rates commonly include a demand charge component, based on some measure of the customer’s peak demand. Customer-sited solar PV can potentially reduce demand charges, but the magnitude of these savings can be difficult to predict, given variations in demand charge designs, customer loads, and PV generation profiles. Moreover, depending on the circumstances, demand charges from solar may or may not align well with associated utility cost savings. Lawrence Berkeley National Laboratory (Berkeley Lab) and the National Renewable Energy Laboratory (NREL) are collaborating in a series of studies to understand how solar PV can reduce demand charge levels for a variety of customer types and demand charges designs. Previous work focused on residential customs with solar. This study, instead, focuses on commercial customers and seeks to understand the extent and conditions under which rooftop can solar reduce commercial demand charges. To answer these questions, we simulate demand charge savings for a broad range of commercial customer types, demand charge designs, locations, and PV system characteristics. This particular analysis does not include storage, but a subsequent analysis in this series will evaluate demand charge savings for commercial customers with solar and storage.

Charging and heat collection by a positively charged dust grain in a plasma.

Science.gov (United States)

Delzanno, Gian Luca; Tang, Xian-Zhu

2014-07-18

Dust particulates immersed in a quasineutral plasma can emit electrons in several important applications. Once electron emission becomes strong enough, the dust enters the positively charged regime where the conventional orbital-motion-limited (OML) theory can break down due to potential-well effects on trapped electrons. A minimal modification of the trapped-passing boundary approximation in the so-called OML(+) approach is shown to accurately predict the dust charge and heat collection flux for a wide range of dust size and temperature.

Charge Injection and Current Flow in Organic Light Emitting Diodes

Science.gov (United States)

Smith, D. L.; Davids, P. S.; Heller, C. M.; Crone, B. K.; Campbell, I. H.; Barashkov, N. N.; Ferraris, J. P.

1997-03-01

We present a comparison between device model calculations and current-voltage measurements for a series of organic LED structures. The Schottky energy barrier of an injecting contact is systematically varied by changing the metal used to form that contact. The current-voltage characteristics of the structures are described using a device model that considers charge injection, transport and space charge effects in the low mobility organic material. Charge injection into the organic material is controlled by the Schottky energy barrier of the metal/organic contact. For Schottky energy barriers greater than about 0.4 eV injection into the organic material is the principal limitation to current flow. In this regime the net injected charge density is relatively small, the electric field in the structure is nearly uniform, and space charge effects are not important. For smaller energy barriers relatively large charge densities are injected into the organic material and space charge effects become the dominant limit to current flow. The measured current-voltage characteristics are quantitatively described by the device model using Schottky barrier values independently determined by internal photoemission and electroabsorption measurements.

Simulating charge transport to understand the spectral response of Swept Charge Devices

Science.gov (United States)

Athiray, P. S.; Sreekumar, P.; Narendranath, S.; Gow, J. P. D.

2015-11-01

Context. Swept Charge Devices (SCD) are novel X-ray detectors optimized for improved spectral performance without any demand for active cooling. The Chandrayaan-1 X-ray Spectrometer (C1XS) experiment onboard the Chandrayaan-1 spacecraft used an array of SCDs to map the global surface elemental abundances on the Moon using the X-ray fluorescence (XRF) technique. The successful demonstration of SCDs in C1XS spurred an enhanced version of the spectrometer on Chandrayaan-2 using the next-generation SCD sensors. Aims: The objective of this paper is to demonstrate validation of a physical model developed to simulate X-ray photon interaction and charge transportation in a SCD. The model helps to understand and identify the origin of individual components that collectively contribute to the energy-dependent spectral response of the SCD. Furthermore, the model provides completeness to various calibration tasks, such as generating spectral matrices (RMFs - redistribution matrix files), estimating efficiency, optimizing event selection logic, and maximizing event recovery to improve photon-collection efficiency in SCDs. Methods: Charge generation and transportation in the SCD at different layers related to channel stops, field zones, and field-free zones due to photon interaction were computed using standard drift and diffusion equations. Charge collected in the buried channel due to photon interaction in different volumes of the detector was computed by assuming a Gaussian radial profile of the charge cloud. The collected charge was processed further to simulate both diagonal clocking read-out, which is a novel design exclusive for SCDs, and event selection logic to construct the energy spectrum. Results: We compare simulation results of the SCD CCD54 with measurements obtained during the ground calibration of C1XS and clearly demonstrate that our model reproduces all the major spectral features seen in calibration data. We also describe our understanding of interactions at

Charging device for an electrostatic accelerator

International Nuclear Information System (INIS)

Pivovar, L.I.; Khurgin, K.M.

1983-01-01

The invention relates to electrostatic accelerators operating in compressed gases and charged by a charge-carrying belt transport device with driving and driven shafts. The aim of the invention is the increase of service life of the device by decreasing deflection of the charge-carrying belt in high-voltage conductor operation at high voltages. Increase of survice life of the device is provided due to the fact that the belt as a whole is more stable and it runs true without slacking shielding rods

Charge transport in electrically doped amorphous organic semiconductors.

Science.gov (United States)

Yoo, Seung-Jun; Kim, Jang-Joo

2015-06-01

This article reviews recent progress on charge generation by doping and its influence on the carrier mobility in organic semiconductors (OSs). The doping induced charge generation efficiency is generally low in OSs which was explained by the integer charge transfer model and the hybrid charge transfer model. The ionized dopants formed by charge transfer between hosts and dopants can act as Coulomb traps for mobile charges, and the presence of Coulomb traps in OSs broadens the density of states (DOS) in doped organic films. The Coulomb traps strongly reduce the carrier hopping rate and thereby change the carrier mobility, which was confirmed by experiments in recent years. In order to fully understand the doping mechanism in OSs, further quantitative and systematic analyses of charge transport characteristics must be accomplished. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of quick charging system for electric vehicle

Energy Technology Data Exchange (ETDEWEB)

Anegawa, Takafumi

2010-09-15

Despite low environmental impact and high energy efficiency, electric vehicles (EV) have not been widely accepted. The lack of charging infrastructure is one reason. Since lithium-ion battery has high energy density and low internal resistance that allows quick charging, the convenience of EV may be greatly improved if charging infrastructure is prepared adequately. TEPCO aims for EV spread to reduce CO2 emissions and to increase demand for electric power, and has developed quick charging system for fleet-use EV to improve the convenience of EV. And based on research results, we will propose desirable characteristics of quick charger for public use.

Phase separation in strongly correlated electron systems with two types of charge carriers

International Nuclear Information System (INIS)

Kugel, K.I.; Rakhmanov, A.L.; Sboychakov, A.O.

2007-01-01

Full text: A competition between the localization of the charge carriers due to Jahn-Teller distortions and the energy gain due to their delocalization in doped manganite and related magnetic oxides is analyzed based on a Kondo-lattice type model. The resulting effective Hamiltonian is, in fact, a generalization of the Falicov-Kimball model. We find that the number of itinerant charge carriers can be significantly lower than that implied by the doping level x. The phase diagram of the model in the T plane is constructed. The system exhibits magnetic ordered (antiferromagnetic, ferromagnetic, or canted) states as well the paramagnetic states with zero and nonzero density of the itinerant electrons. It is shown that a phase-separation is favorable in energy for a wide doping range. The characteristic size of inhomogeneities in a phase-separated state is of the order of several lattice constants. We also analyzed the two-band Hubbard model in the limit of strong on-site Coulomb repulsion. It was shown that such a system has a tendency to phase separation into the regions with different charge densities even in the absence of magnetic or any other ordering, if the ratio of the bandwidths is large enough. The work was supported by the European project CoMePhS and by the Russian Foundation for Basic Research, project no. 05-02-17600. (authors)

Model improvements to simulate charging in SEM

Science.gov (United States)

Arat, K. T.; Klimpel, T.; Hagen, C. W.

2018-03-01

Charging of insulators is a complex phenomenon to simulate since the accuracy of the simulations is very sensitive to the interaction of electrons with matter and electric fields. In this study, we report model improvements for a previously developed Monte-Carlo simulator to more accurately simulate samples that charge. The improvements include both modelling of low energy electron scattering and charging of insulators. The new first-principle scattering models provide a more realistic charge distribution cloud in the material, and a better match between non-charging simulations and experimental results. Improvements on charging models mainly focus on redistribution of the charge carriers in the material with an induced conductivity (EBIC) and a breakdown model, leading to a smoother distribution of the charges. Combined with a more accurate tracing of low energy electrons in the electric field, we managed to reproduce the dynamically changing charging contrast due to an induced positive surface potential.

Charge collection and space charge distribution in neutron-irradiated epitaxial silicon detectors

Energy Technology Data Exchange (ETDEWEB)

Poehlsen, Thomas

2010-04-15

In this work epitaxial n-type silicon diodes with a thickness of 100 {mu}m and 150 {mu}m are investigated. After neutron irradiation with fluences between 10{sup 14} cm{sup -2} and 4 x 10{sup 15} cm{sup -2} annealing studies were performed. CV-IV curves were taken and the depletion voltage was determined for different annealing times. All investigated diodes with neutron fluences greater than 2 x 10{sup 14} cm{sup -2} showed type inversion due to irradiation. Measurements with the transient current technique (TCT) using a pulsed laser were performed to investigate charge collection effects for temperatures of -40 C, -10 C and 20 C. The charge correction method was used to determine the effective trapping time {tau}{sub eff}. Inconsistencies of the results could be explained by assuming field dependent trapping times. A simulation of charge collection could be used to determine the field dependent trapping time {tau}{sub eff}(E) and the space charge distribution in the detector bulk. Assuming a linear field dependence of the trapping times and a linear space charge distribution the data could be described. Indications of charge multiplication were seen in the irradiated 100 {mu}m thick diodes for all investigated fluences at voltages above 800 V. The space charge distribution extracted from TCT measurements was compared to the results of the CV measurements and showed good agreement. (orig.)

Characteristics of solid-target charge-exchange analyzers for energetic ion diagnostics on tokamaks

International Nuclear Information System (INIS)

Beiersdorfer, P.; Roquemore, A.L.; Kaita, R.

1987-05-01

Compact electrostatic charge-exchange analyzers have been constructed for installation in areas of high magnetic fields and restricted access near tokamak fusion devices. The analyzers employed carbon stripping foils, and have been calibrated for proton energies between 1 and 70 keV. They have been successfully used to study charge-exchange losses in auxiliary-heated tokamak plasmas

Performance improvement of charge-trap memory by using a stacked Zr_0_._4_6Si_0_._5_4O_2/Al_2O_3 charge-trapping layer

International Nuclear Information System (INIS)

Tang, Zhenjie; Hu, Dan; Zhang, Xiwei; Zhao, Yage; Li, Rong

2016-01-01

The postdeposition annealing (PDA)-treated charge-trap flash memory capacitor with stacked Zr_0_._4_6Si_0_._5_4O_2/Al_2O_3 charge-trapping layer flanked by a SiO_2 tunneling oxide and an Al_2O_3 blocking oxide was fabricated and investigated. It is observed that the memory capacitor exhibits prominent memory characteristics with large memory windows 12.8 V in a ±10 V gate sweeping voltage range, faster program/erase speed, and good data-retention characteristics even at 125 C compared to a single charge-trapping layer (Zr_0_._4_6Si_0_._5_4O_2, Zr_0_._7_9Si_0_._2_1O_2, and Zr_0_._4_6Al_1_._0_8O_2_._5_4). The quantum wells and introduced interfacial traps of the stacked trapping layer regulate the storage and loss behavior of charges, and jointly contribute to the improved memory characteristics. Hence, the memory capacitor with a stacked trapping layer is a promising candidate in future nonvolatile charge-trap memory device design and application. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

On the multipole moments of charge distributions

International Nuclear Information System (INIS)

Khare, P.L.

1977-01-01

There are two different standard methods for showing the equivalence of a charge distribution in a small volume tau surrounding a point O, to the superposition of a monopole, a dipole, a quadrupole and poles of higher moments at the point O: (a) to show that the electrostatic potential due to the charge distribution at an outside point is the same as due to these superposed multipoles (including a monopole). (b) to show that the energy of interaction of an external field with the charge distribution is the same as with the superposed equivalent monopole and multipoles. Neither of these methods gives a physical picture of the equivalence of a charge distribution to the superposition of different multipoles. An attempt is made to interpret in physical terms the emergence of the multipoles of different order, that are equivalent to a charge distribution and to show that the magnitudes of the moments of these multipoles are in agreement with the results of both the approaches (a) and (b). This physical interpretation also helps to understand, in a simple manner, some of the wellknown properties of the multipole moments of atoms and nuclei. (K.B.)

Formation of a vertical MOSFET for charge sensing in a Si micro-fluidic channel

International Nuclear Information System (INIS)

Lyu, Hong-Kun; Kim, Dong-Sun; Shin, Jang-Kyoo; Choi, Pyung; Lee, Jong-Hyun; Park, Hey-Jung; Park, Chin-Sung; Lim, Geun-Bae

2004-01-01

We have formed a fluidic channel that can be used in micro-fluidic systems and fabricated a 3-dimensional vertical metal-oxide semiconductor field-effect transistor (vertical MOSFET) in the convex corner of a Si micro-fluidic channel by using an anisotropic tetramethyl ammonium hydroxide (TMAH) etching solution. A Au/Cr layer was used for the gate metal and might be useful for detecting charged biomolecules. The electrical characteristics of the vertical MOSFET and its operation as a chemical sensor were investigated. At V DS = -5 V and V GS = -5 V the drain current of the device was -22.5 μA and the threshold voltage was about -1.4 V. A non-planar, non-rectangular vertical MOSFET with a trapezoidal gate was transformed into an equivalent rectangularly based one by using a Schwartz-Christoffel transformation. The LEVEL1 device parameters of the vertical MOSFET were extracted from the measured electrical device characteristics and were used in the SPICE simulation for the vertical MOSFET. The measured and the simulated results for the vertical PMOSFET showed relatively good agreement. When the vertical MOSFET was dipped into a thiol DNA solution, the drain current decreased due to charged biomolecules probably being adsorbed on the gate, which indicates that a vertical MOSFET in a Si micro-fluidic channel might be useful for sensing charged biomolecules.

Effects of Charge-Transfer Excitons on the Photophysics of Organic Semiconductors

Science.gov (United States)

Hestand, Nicholas J.

The field of organic electronics has received considerable attention over the past several years due to the promise of novel electronic materials that are cheap, flexible and light weight. While some devices based on organic materials have already emerged on the market (e.g. organic light emitting diodes), a deeper understanding of the excited states within the condensed phase is necessary both to improve current commercial products and to develop new materials for applications that are currently in the commercial pipeline (e.g. organic photovoltaics, wearable displays, and field effect transistors). To this end, a model for pi-conjugated molecular aggregates and crystals is developed and analyzed. The model considers two types of electronic excitations, namely Frenkel and charge-transfer excitons, both of which play a prominent role in determining the nature of the excited states within tightly-packed organic systems. The former consist of an electron-hole pair bound to the same molecule while in the later the electron and hole are located on different molecules. The model also considers the important nuclear reorganization that occurs when the system switches between electronic states. This is achieved using a Holstein-style Hamiltonian that includes linear vibronic coupling of the electronic states to the nuclear motion associated with the high frequency vinyl-stretching and ring-breathing modes. Analysis of the model reveals spectroscopic signatures of charge-transfer mediated J- and H-aggregation in systems where the photophysical properties are determined primarily by charge-transfer interactions. Importantly, such signatures are found to be sensitive to the relative phase of the intermolecular electron and hole transfer integrals, and the relative energy of the Frenkel and charge-transfer states. When the charge-transfer integrals are in phase and the energy of the charge-transfer state is higher than the Frenkel state, the system exhibits J

Self-consistent simulation studies of periodically focused intense charged-particle beams

International Nuclear Information System (INIS)

Chen, C.; Jameson, R.A.

1995-01-01

A self-consistent two-dimensional model is used to investigate intense charged-particle beam propagation through a periodic solenoidal focusing channel, particularly in the regime in which there is a mismatch between the beam and the focusing channel. The present self-consistent studies confirm that mismatched beams exhibit nonlinear resonances and chaotic behavior in the envelope evolution, as predicted by an earlier envelope analysis [C. Chen and R. C. Davidson, Phys. Rev. Lett. 72, 2195 (1994)]. Transient effects due to emittance growth are studied, and halo formation is investigated. The halo size is estimated. The halo characteristics for a periodic focusing channel are found to be qualitatively the same as those for a uniform focusing channel. A threshold condition is obtained numerically for halo formation in mismatched beams in a uniform focusing channel, which indicates that relative envelope mismatch must be kept well below 20% to prevent space-charge-dominated beams from developing halos

Magnetically charged calorons with non-trivial holonomy

Science.gov (United States)

Kato, Takumi; Nakamula, Atsushi; Takesue, Koki

2018-06-01

Instantons in pure Yang-Mills theories on partially periodic space R^3× {S}^1 are usually called calorons. The background periodicity brings on characteristic features of calorons such as non-trivial holonomy, which plays an essential role for confinement/deconfinement transition in pure Yang-Mills gauge theory. For the case of gauge group SU(2), calorons can be interpreted as composite objects of two constituent "monopoles" with opposite magnetic charges. There are often the cases that the two monopole charges are unbalanced so that the calorons possess net magnetic charge in R3. In this paper, we consider several mechanism how such net magnetic charges appear for certain types of calorons through the ADHM/Nahm construction with explicit examples. In particular, we construct analytically the gauge configuration of the (2 , 1)-caloron with U(1)-symmetry, which has intrinsically magnetic charge.

Charging a Capacitor with a Photovoltaic Module

Science.gov (United States)

Aguilar, Horacio Munguía; Maldonado, Rigoberto Franco; Navarro, Luis Barba

2017-01-01

Charging a capacitor with a photovoltaic module is an experiment which reveals a lot about the modules characteristics. It is customary to represent these characteristics with an equivalent circuit whose elements represent its physical parameters. The behavior of a photovoltaic module is very similar to that of a single cell but the electric…

Large spin accumulation due to spin-charge coupling across a break-junction

Science.gov (United States)

Chen, Shuhan; Zou, Han; Chui, Siu-Tat; Ji, Yi

2013-03-01

We investigate large spin signals in break-junction nonlocal spin valves (NLSV). The break-junction is a nanometer-sized vacuum tunneling gap between the spin detector and the nonmagnetic channel, formed by electro-static discharge. The spin signals can be either inverted or non-inverted and the magnitudes are much larger than those of standard NLSV. Spin signals with high percentage values (10% - 0%) have been observed. When the frequency of the a.c. modulation is varied, the absolute magnitudes of signals remain the same although the percentage values change. These observations affirm the nonlocal nature of the measurements and rule out local magnetoresistive effects. Owing to the spin-charge coupling across the break-junction, the spin accumulation in a ferromagnet splits into two terms. One term decays on the charge screening length (0.1 nm) and the other decays on the spin diffusion length (10 nm nm). The magnitude of the former is proportional to the resistance of the junction. Therefore a highly resistive break-junction leads to a large spin accumulation and thereby a large spin signal. The signs of the spin signal are determined by the relationship between spin-dependent conductivities, diffusion constants, and density of states of the ferromagnet. This work was supported by US DOE grant No. DE-FG02-07ER46374.

Modeling charge polarization voltage for large lithium-ion batteries in electric vehicles

Directory of Open Access Journals (Sweden)

Yan Jiang

2013-06-01

Full Text Available Purpose: Polarization voltage of the lithium-ion battery is an important parameter that has direct influence on battery performance. The paper aims to analyze the impedance characteristics of the lithium-ion battery based on EIS data. Design/methodology/approach: The effects of currents, initial SOC of the battery on charge polarization voltage are investigated, which is approximately linear function of charge current. The change of charge polarization voltage is also analyzed with the gradient analytical method in the SOC domain. The charge polarization model with two RC networks is presented, and parts of model parameters like Ohmic resistance and charge transfer impedance are estimated by both EIS method and battery constant current testing method. Findings: This paper reveals that the Ohmic resistance accounts for much contribution to battery total polarization compared to charge transfer impedance. Practical implications: Experimental results demonstrate the efficacy of the model with the proposed identification method, which provides the foundation for battery charging optimization. Originality/value: The paper analyzed the impedance characteristics of the lithium-ion battery based on EIS data, presented a charge polarization model with two RC networks, and estimated parameters like Ohmic resistance and charge transfer impedance.

Frequency hopping due to acousto-electric interaction in ZnO based surface acoustic wave oscillator

Science.gov (United States)

Dasgupta, Daipayan; Sreenivas, K.

2011-08-01

A 36 MHz surface acoustic wave delay line based oscillator has been used to study the effect of acousto-electric interaction due to photo generated charge carriers in rf sputtered ZnO film under UV illumination (λ = 365 nm, 20-100 μW/cm2). Design aspects for developing a delay line based SAW oscillator are specified. The observed linear downshift in frequency (2.2 to 19.0 kHz) with varying UV intensity (20-100 μW/cm2) is related to the fractional velocity change due to acousto-electric interaction. UV illumination level of 100 μW/cm2 leads to a characteristic frequency hopping behavior arising due to a change in the oscillation criteria, and is attributed to the complex interplay between the increased attenuation and velocity shift.

Charge-density depinning at metal contacts of graphene field-effect transistors

OpenAIRE

Nouchi, Ryo; Tanigaki, Katsumi

2010-01-01

An anomalous distortion is often observed in the transfer characteristics of graphene field-effect transistors. We fabricate graphene transistors with ferromagnetic metal electrodes, which reproducibly display distorted transfer characteristics, and show that the distortion is caused by metal-graphene contacts with no charge-density pinning effect. The pinning effect, where the gate voltage cannot tune the charge density of graphene at the metal electrodes, has been experimentally observed; h...

Charge exchange in collisions of beryllium with its ion.

Science.gov (United States)

Zhang, Peng; Dalgarno, Alexander; Côté, Robin; Bodo, Enrico

2011-11-14

Close-coupling calculations of the resonance and near resonance charge exchange in ion-atom collisions of Be at low and intermediate energies are presented. Accurate ab initio calculations are carried out of the Born-Oppenheimer potentials and the non-adiabatic couplings that are due to the finite nuclear masses and drive the near resonance charge exchange. We show that the near resonance charge exchange cross section follows Wigner's threshold law of inelastic processes for energies below 10(-8) eV and that the zero temperature rate constant for it is 4.5 × 10(-10) cm(3) s(-1). At collision energies much larger than the isotope shift of the ionization potentials of the atoms, we show that the near resonance charge exchange process is equivalent to the resonance charge exchange with cross sections having a logarithmic dependence. We also investigate the perturbation to the charge exchange process due to the non-adiabatic interaction to an electronic excited state. We show that the influence is negligible at low temperatures and still small at intermediate energies despite the presence of resonances.

Quantification of the internalization patterns of superparamagnetic iron oxide nanoparticles with opposite charge

Directory of Open Access Journals (Sweden)

Schweiger Christoph

2012-07-01

Full Text Available Abstract Time-resolved quantitative colocalization analysis is a method based on confocal fluorescence microscopy allowing for a sophisticated characterization of nanomaterials with respect to their intracellular trafficking. This technique was applied to relate the internalization patterns of nanoparticles i.e. superparamagnetic iron oxide nanoparticles with distinct physicochemical characteristics with their uptake mechanism, rate and intracellular fate. The physicochemical characterization of the nanoparticles showed particles of approximately the same size and shape as well as similar magnetic properties, only differing in charge due to different surface coatings. Incubation of the cells with both nanoparticles resulted in strong differences in the internalization rate and in the intracellular localization depending on the charge. Quantitative and qualitative analysis of nanoparticles-organelle colocalization experiments revealed that positively charged particles were found to enter the cells faster using different endocytotic pathways than their negative counterparts. Nevertheless, both nanoparticles species were finally enriched inside lysosomal structures and their efficiency in agarose phantom relaxometry experiments was very similar. This quantitative analysis demonstrates that charge is a key factor influencing the nanoparticle-cell interactions, specially their intracellular accumulation. Despite differences in their physicochemical properties and intracellular distribution, the efficiencies of both nanoparticles as MRI agents were not significantly different.

Investigating Recombination and Charge Carrier Dynamics in a One-Dimensional Nanopillared Perovskite Absorber.

Science.gov (United States)

Kwon, Hyeok-Chan; Yang, Wooseok; Lee, Daehee; Ahn, Jihoon; Lee, Eunsong; Ma, Sunihl; Kim, Kyungmi; Yun, Seong-Cheol; Moon, Jooho

2018-05-22

Organometal halide perovskite materials have become an exciting research topic as manifested by intense development of thin film solar cells. Although high-performance solar-cell-based planar and mesoscopic configurations have been reported, one-dimensional (1-D) nanostructured perovskite solar cells are rarely investigated despite their expected promising optoelectrical properties, such as enhanced charge transport/extraction. Herein, we have analyzed the 1-D nanostructure effects of organometal halide perovskite (CH 3 NH 3 PbI 3- x Cl x ) on recombination and charge carrier dynamics by utilizing a nanoporous anodized alumina oxide scaffold to fabricate a vertically aligned 1-D nanopillared array with controllable diameters. It was observed that the 1-D perovskite exhibits faster charge transport/extraction characteristics, lower defect density, and lower bulk resistance than the planar counterpart. As the aspect ratio increases in the 1-D structures, in addition, the charge transport/extraction rate is enhanced and the resistance further decreases. However, when the aspect ratio reaches 6.67 (diameter ∼30 nm), the recombination rate is aggravated due to high interface-to-volume ratio-induced defect generation. To obtain the full benefits of 1-D perovskite nanostructuring, our study provides a design rule to choose the appropriate aspect ratio of 1-D perovskite structures for improved photovoltaic and other optoelectrical applications.

Nonlinear space charge effect of bunched beam in linac

International Nuclear Information System (INIS)

Chen Yinbao

1992-02-01

The nonlinear space charge effect due to the nonuniform particle density distribution in bunched beam of a linac is discussed. The formulae of nonlinear space charge effect and nonlinear focusing forces were derived for the bunched beam with Kapchinskij-Vladimirskij (K-V) distribution, waterbag (WB) distribution, parabolic (PA) distribution, and Gauss (GA) distribution in both of the space charge disk model and space charge cylinder model in the waveguide of a linac

Analysis of Conduction and Charging Mechanisms in Atomic Layer Deposited Multilayered HfO2/Al2O3 Stacks for Use in Charge Trapping Flash Memories

Directory of Open Access Journals (Sweden)

Nenad Novkovski

2018-01-01

Full Text Available Method for characterization of electrical and trapping properties of multilayered high permittivity stacks for use in charge trapping flash memories is proposed. Application of the method to the case of multilayered HfO2/Al2O3 stacks is presented. By applying our previously developed comprehensive model for MOS structures containing high-κ dielectrics on the J-V characteristics measured in the voltage range without marked degradation and charge trapping (from −3 V to +3 V, several parameters of the structure connected to the interfacial layer and the conduction mechanisms have been extracted. We found that the above analysis gives precise information on the main characteristics and the quality of the injection layer. C-V characteristics of stressed (with write and erase pulses structures recorded in a limited range of voltages between −1 V and +1 V (where neither significant charge trapping nor visible degradation of the structures is expected to occur were used in order to provide measures of the effect of stresses with no influence of the measurement process. Both trapped charge and the distribution of interface states have been determined using modified Terman method for fresh structures and for structures stressed with write and erase cycles. The proposed method allows determination of charge trapping and interface state with high resolution, promising a precise characterization of multilayered high permittivity stacks for use in charge trapping flash memories.

The role of interfacial water layer in atmospherically relevant charge separation

Science.gov (United States)

Bhattacharyya, Indrani

Charge separation at interfaces is important in various atmospheric processes, such as thunderstorms, lightning, and sand storms. It also plays a key role in several industrial processes, including ink-jet printing and electrostatic separation. Surprisingly, little is known about the underlying physics of these charging phenomena. Since thin films of water are ubiquitous, they may play a role in these charge separation processes. This talk will focus on the experimental investigation of the role of a water adlayer in interfacial charging, with relevance to meteorologically important phenomena, such as atmospheric charging due to wave actions on oceans and sand storms. An ocean wave generates thousands of bubbles, which upon bursting produce numerous large jet droplets and small film droplets that are charged. In the 1960s, Blanchard showed that the jet droplets are positively charged. However, the charge on the film droplets was not known. We designed an experiment to exclusively measure the charge on film droplets generated by bubble bursting on pure water and aqueous salt solution surfaces. We measured their charge to be negative and proposed a model where a slight excess of hydroxide ions in the interfacial water layer is responsible for generating these negatively charged droplets. The findings from this research led to a better understanding of the ionic disposition at the air-water interface. Sand particles in a wind-blown sand layer, or 'saltation' layer, become charged due to collisions, so much so, that it can cause lightning. Silica, being hydrophilic, is coated with a water layer even under low-humidity conditions. To investigate the importance of this water adlayer in charging the silica surfaces, we performed experiments to measure the charge on silica surfaces due to contact and collision processes. In case of contact charging, the maximum charge separation occurred at an optimum relative humidity. On the contrary, in collisional charging process, no

Characteristics of transitory multi-charged molecular ions produced by an intense femtosecond laser impulse; Etats electroniques des ions moleculaires multicharges transitoires produits par une impulsion laser femtoseconde intense

Energy Technology Data Exchange (ETDEWEB)

Quaglia, L

2001-12-01

The study of the molecular multi-ionization is narrowly linked to the dynamics of excitation and fragmentation for which the experimental observables rest on the characteristics of the fragmentation products, these characteristics are: intern energy, kinetic energy and charge states. The first chapter sets the problem. The second chapter presents the experimental tools used and developed in this work, the technologies of the detection of ions or of fluorescence are also described. The chapter 3 gathers the theoretical aspects: quantum chemistry and CASSCF (complete active space self consistent field) methods have been used to compute the potential energy curves of multi-charged ions, the two-dimensional hydrodynamic model derived from the Thomas-Fermi model is introduced to tackle the molecular re-orientation. The chapter 4 presents the experimental study of highly excited states by using fluorescence detection methods. The chapter 5 is dedicated to the study of low excited states by measuring kinetic energy spectra and by comparison with potential energy curves of molecular multi-charged ions. The chapter 6 presents experiments with 2 impulses and the results given by the Thomas-Fermi model applied to the re-orientation of the N{sub 2}O molecule. (A.C.)

Behaviour of total surface charge in SiO2-Si system under short-pulsed ultraviolet irradiation cycles characterised by surface photo voltage technique

International Nuclear Information System (INIS)

Kang, Ban-Hong; Lee, Wah-Pheng; Yow, Ho-Kwang; Tou, Teck-Yong

2009-01-01

Effects of time-accumulated ultraviolet (UV) irradiation and surface treatment on thermally oxidized p-type silicon wafers were investigated by using the surface photo voltage (SPV) technique via the direct measurement of the total surface charge, Q SC . The rise and fall times of Q sc curves, as a function of accumulated UV irradiation, depended on the thermal oxide thickness. A simple model was proposed to explain the time-varying characteristics of Q sc based on the UV-induced bond breaking of SiOH and SiH, and photoemission of bulk electrons to wafer surface where O 2 - charges were formed. While these mechanisms resulted in charge variations and hence in Q sc , these could be removed by rinsing the silicon wafers in de-ionized water followed by spin-dry or blow-dry by an ionizer fan. Empirical parameters were used in the model simulations and curve-fitting of Q SC . The simulated results suggested that initial changes in the characteristic behaviour of Q sc were mainly due to the net changes in the positive and negative charges, but subsequently were dominated by the accumulation of O 2 - during the UV irradiation.

Correlation of Disorder and Charge Transport in a Range of Indacenodithiophene-Based Semiconducting Polymers

KAUST Repository

Nikolka, Mark

2017-12-13

Over the past 25 years, various design motifs have emerged for the development of organic semiconductors for demanding applications in flexible organic light emitting diode display backplanes or even printed organic logic. Due to their large area uniformity paired with high charge carrier mobilities, conjugated polymers have attracted increasing attention in this respect. However, the performances delivered by current generation conjugated polymers still fall short of many industrial requirements demanding devices with ideal transistor characteristics and higher mobilities. The discovery of conjugated polymers with low energetic disorder, such as the indacenodithiophene-based polymer indacenodithiophene-co-benzothiadiazole, represent an exciting opportunity to breach this chasm if these materials can be further optimized while maintaining their low disorder. Here, it is shown how both the charge transport properties as well as the energetic disorder are affected by tuning the molecular structure of a large range of indacenodithiophene-based semiconducting polymer derivatives. This study allows to understand better the interplay between molecular design and structure of the polymer backbone and the degree of energetic disorder that governs the charge transport properties in thin polymer films.

Crossover from band-like to thermally activated charge transport in organic transistors due to strain-induced traps

KAUST Repository

Mei, Yaochuan

2017-08-02

The temperature dependence of the charge-carrier mobility provides essential insight into the charge transport mechanisms in organic semiconductors. Such knowledge imparts critical understanding of the electrical properties of these materials, leading to better design of high-performance materials for consumer applications. Here, we present experimental results that suggest that the inhomogeneous strain induced in organic semiconductor layers by the mismatch between the coefficients of thermal expansion (CTE) of the consecutive device layers of field-effect transistors generates trapping states that localize charge carriers. We observe a universal scaling between the activation energy of the transistors and the interfacial thermal expansion mismatch, in which band-like transport is observed for similar CTEs, and activated transport otherwise. Our results provide evidence that a high-quality semiconductor layer is necessary, but not sufficient, to obtain efficient charge-carrier transport in devices, and underline the importance of holistic device design to achieve the intrinsic performance limits of a given organic semiconductor. We go on to show that insertion of an ultrathin CTE buffer layer mitigates this problem and can help achieve band-like transport on a wide range of substrate platforms.

Crossover from band-like to thermally activated charge transport in organic transistors due to strain-induced traps.

Science.gov (United States)

Mei, Yaochuan; Diemer, Peter J; Niazi, Muhammad R; Hallani, Rawad K; Jarolimek, Karol; Day, Cynthia S; Risko, Chad; Anthony, John E; Amassian, Aram; Jurchescu, Oana D

2017-08-15

The temperature dependence of the charge-carrier mobility provides essential insight into the charge transport mechanisms in organic semiconductors. Such knowledge imparts critical understanding of the electrical properties of these materials, leading to better design of high-performance materials for consumer applications. Here, we present experimental results that suggest that the inhomogeneous strain induced in organic semiconductor layers by the mismatch between the coefficients of thermal expansion (CTE) of the consecutive device layers of field-effect transistors generates trapping states that localize charge carriers. We observe a universal scaling between the activation energy of the transistors and the interfacial thermal expansion mismatch, in which band-like transport is observed for similar CTEs, and activated transport otherwise. Our results provide evidence that a high-quality semiconductor layer is necessary, but not sufficient, to obtain efficient charge-carrier transport in devices, and underline the importance of holistic device design to achieve the intrinsic performance limits of a given organic semiconductor. We go on to show that insertion of an ultrathin CTE buffer layer mitigates this problem and can help achieve band-like transport on a wide range of substrate platforms.

Ponderomotive enhancement of charged particle beam limiting current

International Nuclear Information System (INIS)

Grebogi, C.; Uhm, H.S.

1987-01-01

The space charge limiting current problem is investigated for a magnetized particle beam propagating in a cylindrical drift tube and in presence of a waveguide mode. It is shown that with a proper choice of a waveguide mode, the limiting current can be greatly enhanced due to ponderomotive effects. Physically, this is accomplished by using the ponderomotive energy to reduce the potential depression due to the beam's self space charge field. Formulas for the limiting current as a function of beam energy and waveguide r.f. field for solid and hollow beams are derived. It is found from these formulas that, in appropriate parameter regimes, the space charge limiting current, say, of a 250kV bem can be enhanced by 70%

The influence of charge and the distribution of charge in the polar region of phospholipids on the activity of UDP-glucuronosyltransferase.

Science.gov (United States)

Zakim, D; Eibl, H

1992-07-05

Studies of the mechanism of lipid-induced regulation of the microsomal enzyme UDP-glucuronosyltransferase have been extended by examining the influence of charge within the polar region on the ability of lipids to activate delipidated pure enzyme. The effects of net negative charge, of charge separation in phosphocholine, and of the distribution of charge in the polar region of lipids were studied using the GT2p isoform isolated from pig liver. Prior experiments have shown that lipids with net negative charge inhibit the enzyme (Zakim, D., Cantor, M., and Eibl, H. (1988) J. Biol. Chem. 263, 5164-5169). The current experiments show that the extent of inhibition on a molar basis increases as the net negative charge increases from -1 to -2. The inhibitory effect of negatively charged lipids is on the functional state of the enzyme and is not due to electrostatic repulsion of negatively charged substrates of the enzyme. Although the inhibitory effect of net negative charge is removed when negative charge is balanced by a positive charge due to a quaternary nitrogen, neutrality of the polar region is not a sufficient condition for activation of the enzyme. In addition to a balance of charge between Pi and the quaternary nitrogen, the distance between the negative and positive charges and the orientation of the dipole created by them are critical for activation of GT2p. The negative and positive charges must be separated by the equivalent of three -CH2- groups for optimal activation by a lipid. Shortening this distance by one -CH2- unit leads to a lipid that is ineffective in activating the enzyme. Reversal of the orientation of the dipole in which the negative charge is on the polymethylene side of the lipid-water interface and the positive charge extends into water also produces a lipid that is not effective for activating GT2p. On the other hand, lipids with phosphoserine as the polar region, which has the "normal" P-N distance but carries a net negative charge, do

Combustion characteristics of lemongrass (Cymbopogon flexuosus oil in a partial premixed charge compression ignition engine

Directory of Open Access Journals (Sweden)

Avinash Alagumalai

2015-09-01

Full Text Available Indeed, the development of alternate fuels for use in internal combustion engines has traditionally been an evolutionary process in which fuel-related problems are met and critical fuel properties are identified and their specific limits defined to resolve the problem. In this regard, this research outlines a vision of lemongrass oil combustion characteristics. In a nut-shell, the combustion phenomena of lemongrass oil were investigated at engine speed of 1500 rpm and compression ratio of 17.5 in a 4-stroke cycle compression ignition engine. Furthermore, the engine tests were conducted with partial premixed charge compression ignition-direct injection (PCCI-DI dual fuel system to profoundly address the combustion phenomena. Analysis of cylinder pressure data and heat-release analysis of neat and premixed lemongrass oil were demonstrated in-detail and compared with conventional diesel. The experimental outcomes disclosed that successful ignition and energy release trends can be obtained from a compression ignition engine fueled with lemongrass oil.

Charge and energy transfer interplay in hybrid sensitized solar cells mediated by graphene quantum dots

International Nuclear Information System (INIS)

Mihalache, Iuliana; Radoi, Antonio; Mihaila, Mihai; Munteanu, Cornel; Marin, Alexandru; Danila, Mihai; Kusko, Mihaela; Kusko, Cristian

2015-01-01

Highlights: • We report a one pot synthesis metod of GQD with controlled size and optoelectronic properties. • An improvement of common N3-DSSC characteristics is achieved when GQDs are used as co-sensitiser. • The role of GQD as cosensitisers in hybrid DSSC was investigated and the interplay between charge and energy transfer phenomena mediated by GQDs was demonstrated. • The GQDs presence determines an inhibition of the recombination processes at the TiO 2 /electrolyte interface. - Abstract: We explored the role of graphene quantum dots (GQDs) as co-sensitizers in hybrid dye sensitized solar cell (DSSC) architectures, focusing on various concurring mechanisms, such as: charge transfer, energy transfer and recombination rate, towards light harvesting improvement. GQDs were prepared by the hydrothermal method that allows the tuning of electronic levels and optical properties by employing appropriate precursors and synthesis conditions. The aim was to realize a type II alignment for TiO 2 /GQD/dye hybrid configuration, using standard N3 Ru-dye in order to improve charge transfer. When GQDs were used as co-sensitizers together with N3 Ru-dye, an improvement in power conversion efficiency was achieved, as shown by electrical measurements. The experimental analysis indicates that this improvement arises from the interplay of various mechanisms mediated by GQDs: (i) enhancement of charge separation and collection due to the cascaded alignment of the energy levels; (ii) energy transfer from GQDs to N3 Ru-dye due to the overlap between GQD photoluminescence and N3 Ru-dye absorption spectra; and (iii) reduction of the electron recombination to the redox couple due to the inhibition of the back electron transfer to the electrolyte by the GQDs

Dynamical instability of a charged gaseous cylinder

Science.gov (United States)

Sharif, M.; Mumtaz, Saadia

2017-10-01

In this paper, we discuss dynamical instability of a charged dissipative cylinder under radial oscillations. For this purpose, we follow the Eulerian and Lagrangian approaches to evaluate linearized perturbed equation of motion. We formulate perturbed pressure in terms of adiabatic index by applying the conservation of baryon numbers. A variational principle is established to determine characteristic frequencies of oscillation which define stability criteria for a gaseous cylinder. We compute the ranges of radii as well as adiabatic index for both charged and uncharged cases in Newtonian and post-Newtonian limits. We conclude that dynamical instability occurs in the presence of charge if the gaseous cylinder contracts to the radius R*.

Structure and stability of charged colloid-nanoparticle mixtures

Science.gov (United States)

Weight, Braden M.; Denton, Alan R.

2018-03-01

Physical properties of colloidal materials can be modified by addition of nanoparticles. Within a model of like-charged mixtures of particles governed by effective electrostatic interactions, we explore the influence of charged nanoparticles on the structure and thermodynamic phase stability of charge-stabilized colloidal suspensions. Focusing on salt-free mixtures of particles of high size and charge asymmetry, interacting via repulsive Yukawa effective pair potentials, we perform molecular dynamics simulations and compute radial distribution functions and static structure factors. Analysis of these structural properties indicates that increasing the charge and concentration of nanoparticles progressively weakens correlations between charged colloids. We show that addition of charged nanoparticles to a suspension of like-charged colloids can induce a colloidal crystal to melt and can facilitate aggregation of a fluid suspension due to attractive van der Waals interactions. We attribute the destabilizing influence of charged nanoparticles to enhanced screening of electrostatic interactions, which weakens repulsion between charged colloids. This interpretation is consistent with recent predictions of an effective interaction theory of charged colloid-nanoparticle mixtures.

Guidelines on the Switch Transistors Sizing Using the Symbolic Description for the Cross-Coupled Charge Pump

Directory of Open Access Journals (Sweden)

J. Marek

2017-09-01

Full Text Available This paper presents a symbolic description of the design process of the switch transistors for the cross- coupled charge pump applications. Discrete-time analog circuits are usually designed by the numerical algorithms in the professional simulator software which can be an extremely time-consuming process in contrast to described analytical procedure. The significant part of the pumping losses is caused by the reverse current through the switch transistors due to continuous-time voltage change on the main capacitors. Design process is based on the analytical expression of the time response characteristics of the pump stage as an analog system with using BSIM model equations. The main benefit of the article is the analytical transistors sizing formula, so that the maximum voltage gain is achieved. The diode transistor is dimensioned for the pump requirements, as the maximal pump output ripple voltage, current, etc. The characteristics of the proposed circuit has been verified by simulation in ELDO Spice. Results are valid for N-stage charge pump and also applicable for other model equations as PSP, EKV.

Spacecraft Charging Modeling -- Nascap-2k 2014 Annual Report

Science.gov (United States)

2014-09-19

appears to work similarly in Internet Explorer, FireFox , and Opera, but fails in Safari and Chrome. Note that the SEE Spacecraft Charging Handbook is... Characteristics of Spacecraft Charging in Low Earth Orbit, J Geophys Res. 11 7, doi: 10.1029/20 11JA016875, 2012. 2 M. Cho, K. Saito, T. Hamanaga, Data

Induced Current Characteristics Due to Laser Induced Plasma and Its Application to Laser Processing Monitoring

International Nuclear Information System (INIS)

Madjid, Syahrun Nur; Idris, Nasrullah; Kurniawan, Koo Hendrik; Kagawa, Kiichiro

2011-01-01

In laser processing, suitable conditions for laser and gas play important role in ensuring a high quality of processing. To determine suitable conditions, we employed the electromagnetic phenomena associated with laser plasma generation. An electrode circuit was utilised to detect induced current due to the fast electrons propelled from the material during laser material processing. The characteristics of induced current were examined by changing parameters such as supplied voltage, laser pulse energy, number of laser shots, and type of ambient gas. These characteristics were compared with the optical emission characteristics. It was shown that the induced current technique proposed in this study is much more sensitive than the optical method in monitoring laser processing, that is to determine the precise focusing condition, and to accurately determine the moment of completion of laser beam penetration. In this study it was also shown that the induced current technique induced by CW CO 2 laser can be applied in industrial material processing for monitoring the penetration completion in a stainless steel plate drilling process.

Effect of re-oxidation annealing process on the SiO2/SiC interface characteristics

International Nuclear Information System (INIS)

Yan Hongli; Jia Renxu; Tang Xiaoyan; Song Qingwen; Zhang Yuming

2014-01-01

The effect of the different re-oxidation annealing (ROA) processes on the SiO 2 /SiC interface characteristics has been investigated. With different annealing processes, the flat band voltage, effective dielectric charge density and interface trap density are obtained from the capacitance—voltage curves. It is found that the lowest interface trap density is obtained by the wet-oxidation annealing process at 1050 °C for 30 min, while a large number of effective dielectric charges are generated. The components at the SiO 2 /SiC interface are analyzed by X-ray photoelectron spectroscopy (XPS) testing. It is found that the effective dielectric charges are generated due to the existence of the C and H atoms in the wet-oxidation annealing process. (semiconductor technology)

Spin-Charge Separation in Finite Length Metallic Carbon Nanotubes

KAUST Repository

Zhang, Yongyou; Zhang, Qingyun; Schwingenschlö gl, Udo

2017-01-01

Using time-dependent density functional theory, we study the optical excitations in finite length carbon nanotubes. Evidence of spin-charge separation is given in the spacetime domain. We demonstrate that the charge density wave is due to collective

Long-wavelength behaviour of charge-charge structure factor in insulating and metallic ground state of condensed hydrogen under pressure

International Nuclear Information System (INIS)

Amato, M.A.; March, N.H.

1988-09-01

Using the quantum Monte Carlo charge-charge structure factor S qq (k) it is argued that (i) in the metallic phase the small k expasion is non-analytic at order k 5 , reflecting plasmon dispersion, while in the insulating phase the non-analyticity occurs at O(k 3 ), due to van der Waals interaction between the protons. (author) [pt

[Left-sided endocarditis due to gram-negative bacilli: epidemiology and clinical characteristics].

Science.gov (United States)

Noureddine, Mariam; de la Torre, Javier; Ivanova, Radka; Martínez, Francisco José; Lomas, Jose María; Plata, Antonio; Gálvez, Juan; Reguera, Jose María; Ruiz, Josefa; Hidalgo, Carmen; Luque, Rafael; García-López, María Victoria; de Alarcón, Arístides

2011-04-01

The aim of this study is to describe the epidemiological, clinical characteristics, and outcome of patients with left-side endocarditis caused by gram-negative bacteria. Prospective multicenter study of left-sided infective endocarditis reported in the Andalusian Cohort for the Study of Cardiovascular Infections between 1984 and 2008. Among the 961 endocarditis, 24 (2.5%) were caused by gram-negative bacilli. The most common pathogens were Escherichia coli, Pseudomonas aeruginosa and Salmonella enterica. Native valves (85.7%) were mainly affected, most of them with previous valve damage (57%). Comorbidity was greater (90% vs 39%; P=.05) than in endocarditis due to other microorganism, the most frequent being, diabetes, hepatic cirrhosis and neoplasm. A previous manipulation was found in 47.6% of the cases, and 37% were considered hospital-acquired. Renal failure (41%), central nervous system involvement (33%) and ventricular dysfunction (45%) were the most frequent complications. Five cases (21%) required cardiac surgery, mostly due to ventricular dysfunction. More than 50% of cases were treated with aminoglycosides, but this did not lead to a better outcome or prognosis. Mortality (10 patients) was higher than that reported with other microorganisms (41% vs 35%; P=.05). Left-sided endocarditis due to gram-negative bacilli is a rare disease, which affects patients with major morbidities and often with a previous history of hospital manipulations. Cardiac, neurological and renal complications are frequent and associated with a high mortality. The association of aminoglycosides in the antimicrobial treatment did not involve a better outcome or prognosis. Copyright © 2010 Elsevier España, S.L. All rights reserved.

Charge transport in a CoPt3 nanocrystal microwire

International Nuclear Information System (INIS)

Beecher, P.; De Marzi, G.; Quinn, A.J.; Redmond, G.; Shevchenko, E.V.; Weller, H.

2004-01-01

The electrical characteristics of single CoPt 3 nanocrystal microwires formed by magnetic field-directed growth from colloidal solutions are presented. The wires comprise disordered assemblies of discrete nanocrystals, separated from each other by protective organic ligand shells. Electrical data indicate that the activated charge transport properties of the wires are determined by the nanocrystal charging energy, governed by the size and capacitance of the individual nanocrystals. Focused ion beam-assisted deposition of Pt metal at the wire-electrode junctions is employed to optimize the wire-electrode contacts, whilst maintaining the nanocrystal-dominated transport characteristics of these one-dimensional nanocrystal structures

Abnormal Multiple Charge Memory States in Exfoliated Few-Layer WSe2 Transistors.

Science.gov (United States)

Chen, Mikai; Wang, Yifan; Shepherd, Nathan; Huard, Chad; Zhou, Jiantao; Guo, L J; Lu, Wei; Liang, Xiaogan

2017-01-24

To construct reliable nanoelectronic devices based on emerging 2D layered semiconductors, we need to understand the charge-trapping processes in such devices. Additionally, the identified charge-trapping schemes in such layered materials could be further exploited to make multibit (or highly desirable analog-tunable) memory devices. Here, we present a study on the abnormal charge-trapping or memory characteristics of few-layer WSe 2 transistors. This work shows that multiple charge-trapping states with large extrema spacing, long retention time, and analog tunability can be excited in the transistors made from mechanically exfoliated few-layer WSe 2 flakes, whereas they cannot be generated in widely studied few-layer MoS 2 transistors. Such charge-trapping characteristics of WSe 2 transistors are attributed to the exfoliation-induced interlayer deformation on the cleaved surfaces of few-layer WSe 2 flakes, which can spontaneously form ambipolar charge-trapping sites. Our additional results from surface characterization, charge-retention characterization at different temperatures, and density functional theory computation strongly support this explanation. Furthermore, our research also demonstrates that the charge-trapping states excited in multiple transistors can be calibrated into consistent multibit data storage levels. This work advances the understanding of the charge memory mechanisms in layered semiconductors, and the observed charge-trapping states could be further studied for enabling ultralow-cost multibit analog memory devices.

Screening model for nanowire surface-charge sensors in liquid

DEFF Research Database (Denmark)

Sørensen, Martin Hedegård; Mortensen, Asger; Brandbyge, Mads

2007-01-01

The conductance change of nanowire field-effect transistors is considered a highly sensitive probe for surface charge. However, Debye screening of relevant physiological liquid environments challenge device performance due to competing screening from the ionic liquid and nanowire charge carriers....

Microscopic gate-modulation imaging of charge and field distribution in polycrystalline organic transistors

Science.gov (United States)

Matsuoka, Satoshi; Tsutsumi, Jun'ya; Kamata, Toshihide; Hasegawa, Tatsuo

2018-04-01

In this work, a high-resolution microscopic gate-modulation imaging (μ-GMI) technique is successfully developed to visualize inhomogeneous charge and electric field distributions in operating organic thin-film transistors (TFTs). We conduct highly sensitive and diffraction-limit gate-modulation sensing for acquiring difference images of semiconducting channels between at gate-on and gate-off states that are biased at an alternate frequency of 15 Hz. As a result, we observe unexpectedly inhomogeneous distribution of positive and negative local gate-modulation (GM) signals at a probe photon energy of 1.85 eV in polycrystalline pentacene TFTs. Spectroscopic analyses based on a series of μ-GMI at various photon energies reveal that two distinct effects appear, simultaneously, within the polycrystalline pentacene channel layers: Negative GM signals at 1.85 eV originate from the second-derivative-like GM spectrum which is caused by the effect of charge accumulation, whereas positive GM signals originate from the first-derivative-like GM spectrum caused by the effect of leaked gate fields. Comparisons with polycrystalline morphologies indicate that grain centers are predominated by areas with high leaked gate fields due to the low charge density, whereas grain edges are predominantly high-charge-density areas with a certain spatial extension as associated with the concentrated carrier traps. Consequently, it is reasonably understood that larger grains lead to higher device mobility, but with greater inhomogeneity in charge distribution. These findings provide a clue to understand and improve device characteristics of polycrystalline TFTs.

Klystron - Space-charge limited flow, guns, Perveance

International Nuclear Information System (INIS)

Isagawa, S.

1999-01-01

This paper treats Thermionic emission, Cathode as an e - emitter, Space-charge limited effect and 3/2 power law, Perveance, Beam spread due to space charge, Pierce guns, Magnetically immersed guns, Method of gun design including simulations, and Examples, mainly treating E3786, which attendees will operate above 1 MW-CW in a practical exercise course at KEK. (author). 74 refs

Charging conditions research to increase the initial projected velocity at different initial charge temperatures

Science.gov (United States)

Ishchenko, Aleksandr; Burkin, Viktor; Kasimov, Vladimir; Samorokova, Nina; Zykova, Angelica; Diachkovskii, Alexei

2017-11-01

The problems of the defense industry occupy the most important place in the constantly developing modern world. The daily development of defense technology does not stop, nor do studies on internal ballistics. The scientists of the whole world are faced with the task of managing the main characteristics of a ballistic experiment. The main characteristics of the ballistic experiment are the maximum pressure in the combustion chamber Pmax and the projected velocity at the time of barrel leaving UM. During the work the combustion law of the new high-energy fuel was determined in a ballistic experiment for different initial temperatures. This combustion law was used for a parametric study of depending Pmax and UM from a powder charge mass and a traveling charge was carried out. The optimal conditions for loading were obtained for improving the initial velocity at pressures up to 600 MPa for different initial temperatures. In this paper, one of the most promising schemes of throwing is considered, as well as a method for increasing the muzzle velocity of a projected element to 3317 m/s.

Charge collection measurements in single-type column 3D sensors

International Nuclear Information System (INIS)

Scaringella, M.; Polyakov, A.; Sadrozinski, H.F.-W.; Bruzzi, M.; Tosi, C.; Boscardin, M.; Piemonte, C.; Pozza, A.; Ronchin, S.; Zorzi, N.; Dalla Betta, G.-F.

2007-01-01

We report on charge collection studies on 3D silicon detectors of single-type column n-diffusions in p-substrate, configured either as strip or as pad detectors. The charge is generated by penetrating beta particles from a 90 Sr source which, together with a scintillation counter, serves as an electron telescope. The charge collection as a function of bias voltage is compared with the depletion thickness derived from the measured C-V characteristics

Charge and spin separation in one-dimensional systems

International Nuclear Information System (INIS)

Balseiro, C.A.; Jagla, E.A.; Hallberg, K.

1995-01-01

In this article we discuss charge and spin separation and quantum interference in one-dimensional models. After a short introduction we briefly present the Hubbard and Luttinger models and discuss some of the known exact results. We study numerically the charge and spin separation in the Hubbard model. The time evolution of a wave packet is obtained and the charge and spin densities are evaluated for different times. The charge and spin wave packets propagate with different velocities. The results are interpreted in terms of the Bethe-ansatz solution. In section IV we study the effect of charge and spin separation on the quantum interference in a Aharonov-Bohm experiment. By calculating the one-particle propagators of the Luttinger model for a mesoscopic ring with a magnetic field we calculate the Aharonov-Bohm conductance. The conductance oscillates with the magnetic field with a characteristic frequency that depends on the charge and spin velocities. (author)

Cosmology of a charged universe

International Nuclear Information System (INIS)

Barnes, A.

1979-01-01

The Proca generalization of electrodynamics admits the possibility that the universe could possess a net electric charge uniformly distributed throughout space, while possessing no electric field. A charged intergalactic (and intragalactic) medium of this kind could contain enough energy to be of cosmological importance. A general-relativistic model of cosmological expansion dominated by such a charged background has been calculated, and is consistent with present observational limits on the Hubble constant, the decleration parameter, and the age of the universe. However, if this cosmology applied at the present epoch, the very early expansion of the universe would have been much more rapid than in conventional ''big bang'' cosmologies, too rapid for cosmological nucleosynthesis or thermalization of the background radiation to have occurred. Hence, domination of the present expansion by background charge appears to be incompatible with the 3 K background and big-bang production of light elements. If the present background charge density were sufficiently small (but not strictly zero), expansion from the epoch of nucleosynthesis would proceed according to the conventional scenario, but the energy due to the background charge would have dominated at some earlier epoch. This last possibility leads to equality of pressure and energy density in the primordial universe, a condition of special significance in certain cosmological theories

Bulk-Like Electrical Properties Induced by Contact-Limited Charge Transport in Organic Diodes: Revised Space Charge Limited Current

KAUST Repository

Xu, Guangwei

2018-02-22

Charge transport governs the operation and performance of organic diodes. Illuminating the charge-transfer/transport processes across the interfaces and the bulk organic semiconductors is at the focus of intensive investigations. Traditionally, the charge transport properties of organic diodes are usually characterized by probing the current–voltage (I–V) curves of the devices. However, to unveil the landscape of the underlying potential/charge distribution, which essentially determines the I–V characteristics, still represents a major challenge. Here, the electrical potential distribution in planar organic diodes is investigated by using the scanning Kelvin probe force microscopy technique, a method that can clearly separate the contact and bulk regimes of charge transport. Interestingly, by applying to devices based on novel, high mobility organic materials, the space-charge-limited-current-like I–V curves, which are previously believed to be a result of the bulk transport, are surprisingly but unambiguously demonstrated to be caused by contact-limited conduction. A model accounting is developed for the transport properties of both the two metal/organic interfaces and the bulk. The results indicate that pure interface-dominated transport can indeed give rise to I–V curves similar to those caused by bulk transport. These findings provide a new insight into the charge injection and transport processes in organic diodes.

Effect of carbon nano tube working electrode thickness on charge transport kinetics and photo-electrochemical characteristics of dye-sensitized solar cells

Science.gov (United States)

Gacemi, Yahia; Cheknane, Ali; Hilal, Hikmat S.

2018-02-01

Physiochemical processes at the photo-electrode and the counter electrode of dye sensitized solar cells (DSSCs) involving having carbon nanotubes (CNTs) instead of the TiO2 layer, within the working electrode, are simulated in this work. Attention is paid to find the effect of CNT layer thickness on photo-electrochemical (PEC) characteristics of the CNT-DSSCs. Comparison with other conventional TiO2-DSSC systems, taking into account the working electrode film thickness, is also described here. To achieve these goals, a model is presented to explain charge transport and electron recombination which involve electron photo-excitation in dye molecules, injection of electrons from the excited dye to CNT working electrode conduction band, diffusion of electrons inside the CNT electrode, charge transfer between oxidized dye and (I-) and recombination of electrons. The simulation is based on solving non-linear equations using the Newton-Raphson numerical method. This concept is proposed for modelling numerical Faradaic impedance at the photo-electrode and the platinum counter electrode. It then simulates the cell impedance spectrum describing the locus of the three semicircles in the Nyquist diagram. The transient equivalent circuit model is also presented based on optimizing current-voltage curves of CNT-DSSCs so as to optimize the fill factor (FF) and conversion efficiency (η). The results show that the simulated characteristics of CNT-DSSCs, with different active CNT layer thicknesses, are superior to conventional TiO2-DSSCs.

μ+ charge exchange and muonium formation in low pressure gases

International Nuclear Information System (INIS)

Fleming, D.G.; Mikula, R.J.; Garner, D.M.

1982-04-01

Using the basic muon spin rotation technique, the fractions of energetic positive muons thermalizing in diamagnetic environments (fsub(μ)) or as the paramagnetic muonium atom (fsub(Mu)) have been measured in low pressure pure gases (He, Ne, Ar, Kr, Xe, H 2 , N 2 , NH 3 , and CH 4 ) as well as in several gas mixtures (Ne/Xe, Ne/Ar, Ne/NH 3 , Ne/CH 4 ). In the pure gases, the muonium fractions fsub(Mu) are generally found to be smaller than expected from analogous proton charge exchange studies, particularly in the molecular gases. This is probably due to hot atom reactions of muonium following the charge exchange regime. Comparisons with monium formation in condensed matter as well as positronium formation in gases are also presented. In the gas mixtures, the addition of only a few hundred ppm of a dopant gas, which is exothermic for muonium formation (e.g. Xe), gives rise to an fsub(Mu) characteristic of the pure dopant gas itself, demonstrating the importance of the neutralization process right down to thermal energies. In all cases, the experimental signal amplitudes are found to be strongly pressure dependent, which is interpreted in terms of the time spent by the muon as neutral muonium in the charge exchange regime: tsub(n) < 0.2 ns. This time is generally shorter in the case of molecular gases than in rare gases

Spin flip due to the spin–orbit interaction of colliding slow charged particles

International Nuclear Information System (INIS)

Sasorov, P. V.; Fomin, I. V.

2017-01-01

The scattering amplitudes of point charged particles is calculated analytically taking into account the spin–orbit interaction. We have considered two cases typical of a hydrogen-like plasma: scattering of an electron by a heavy ion and scattering of an electron by a free electron. The results have been obtained taking into account the ranges of low collision energies smaller than α"2m_ec"2, where α is the fine structure constant.

Probing the Importance of Charge Flux in Force Field Modeling.

Science.gov (United States)

Sedghamiz, Elaheh; Nagy, Balazs; Jensen, Frank

2017-08-08

We analyze the conformational dependence of atomic charges and molecular dipole moments for a selection of ∼900 conformations of peptide models of the 20 neutral amino acids. Based on a set of reference density functional theory calculations, we partition the changes into effects due to changes in bond distances, bond angles, and torsional angles and into geometry and charge flux contributions. This allows an assessment of the limitations of fixed charge force fields and indications for how to design improved force fields. The torsional degrees of freedom are the main contribution to conformational changes of atomic charges and molecular dipole moments, but indirect effects due to change in bond distances and angles account for ∼25% of the variation. Charge flux effects dominate for changes in bond distances and are also the main component of the variation in bond angles, while they are ∼25% compared to the geometry variations for torsional degrees of freedom. The geometry and charge flux contributions to some extent produce compensating effects.

An insight into the mechanism of charge-transfer of hybrid polymer:ternary/quaternary chalcopyrite colloidal nanocrystals

Directory of Open Access Journals (Sweden)

Parul Chawla

2014-08-01

Full Text Available In this work, we have demonstrated the structural and optoelectronic properties of the surface of ternary/quaternary (CISe/CIGSe/CZTSe chalcopyrite nanocrystallites passivated by tri-n-octylphosphine-oxide (TOPO and tri-n-octylphosphine (TOP and compared their charge transfer characteristics in the respective polymer: chalcopyrite nanocomposites by dispersing them in poly(3-hexylthiophene polymer. It has been found that CZTSe nanocrystallites due to their high crystallinity and well-ordered 3-dimensional network in its pristine form exhibit a higher steric- and photo-stability, resistance against coagulation and homogeneity compared to the CISe and CIGSe counterparts. Moreover, CZTSe nanocrystallites display efficient photoluminescence quenching as evident from the high value of the Stern–Volmer quenching constant (KSV and eventually higher charge transfer efficiency in their respective polymer P3HT:CZTSe composites. We modelled the dependency of the charge transfer from the donor and the charge separation mechanism across the donor–acceptor interface from the extent of crystallinity of the chalcopyrite semiconductors (CISe/CIGSe/CZTSe. Quaternary CZTSe chalcopyrites with their high crystallinity and controlled morphology in conjunction with regioregular P3HT polymer is an attractive candidate for hybrid solar cells applications.

An insight into the mechanism of charge-transfer of hybrid polymer:ternary/quaternary chalcopyrite colloidal nanocrystals.

Science.gov (United States)

Chawla, Parul; Singh, Son; Sharma, Shailesh Narain

2014-01-01

In this work, we have demonstrated the structural and optoelectronic properties of the surface of ternary/quaternary (CISe/CIGSe/CZTSe) chalcopyrite nanocrystallites passivated by tri-n-octylphosphine-oxide (TOPO) and tri-n-octylphosphine (TOP) and compared their charge transfer characteristics in the respective polymer: chalcopyrite nanocomposites by dispersing them in poly(3-hexylthiophene) polymer. It has been found that CZTSe nanocrystallites due to their high crystallinity and well-ordered 3-dimensional network in its pristine form exhibit a higher steric- and photo-stability, resistance against coagulation and homogeneity compared to the CISe and CIGSe counterparts. Moreover, CZTSe nanocrystallites display efficient photoluminescence quenching as evident from the high value of the Stern-Volmer quenching constant (K SV) and eventually higher charge transfer efficiency in their respective polymer P3HT:CZTSe composites. We modelled the dependency of the charge transfer from the donor and the charge separation mechanism across the donor-acceptor interface from the extent of crystallinity of the chalcopyrite semiconductors (CISe/CIGSe/CZTSe). Quaternary CZTSe chalcopyrites with their high crystallinity and controlled morphology in conjunction with regioregular P3HT polymer is an attractive candidate for hybrid solar cells applications.

Battery charging characteristics in small scaled photovoltaic system using resonant DC-DC converter with electric isolation

International Nuclear Information System (INIS)

Isoda, H.; Kimura, G.; Shioya, M.

1990-01-01

The solar energy has been drawing attention of the whole world as a clean and infinite energy, since the globe resource, the globe ecology and so on came into question. The wide applications of the solar energy are being expected in a range from electric power plants to household systems. But the output power induced in the photovoltaic modules is influenced by an intensity of the solar radiation, a temperature of the solar cells and so on, so the various useful forms of the solar energy are being proposed for a purpose of stable power supply. a system described in this paper is a small scaled photovoltaic system with storage batteries. This paper describes the theoretical analyses of the photovoltaic system using a resonant DC-DC converter in order to clarify a desirable circuit condition, besides the experimental results of the battery charging characteristics are presented

Universal transport characteristics of multiple topological superconducting wires with large charging energy

Energy Technology Data Exchange (ETDEWEB)

Kashuba, Oleksiy; Trauzettel, Bjoern [Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg, 97074 Wuerzburg (Germany); Timm, Carsten [Institut fuer Theoretische Physik, TU Dresden, 01062 Dresden (Germany)

2016-07-01

The system with multiple Majorana states coupled to the normal lead can potentially support the interaction between Majorana fermions and electrons. Such system can be implemented by several floating topological superconducting wires with large charging energy asymmetrically coupled to two normal leads. The analysis of the renormalization flow shows that there is a single fixed point - the strong coupling limit of isotropic antiferromagnetic Kondo model. The topological Kondo-like interaction leads also to the selective renormalization of the tunneling coefficients, strongly enhancing one component and suppressing others. Thus, charging energy crucially changes the transport properties of the system leading to the universal single-channel conductance independently from the values of the initial leads-wires coupling.

An experimental study on the heat transfer characteristics of a heat pipe heat exchanger with latent heat storage. Part II: Simultaneous charging/discharging modes

International Nuclear Information System (INIS)

Liu Zhongliang; Wang Zengyi; Ma Chongfang

2006-01-01

In this part of the paper, the performance of the simultaneous charging/discharging operation modes of the heat pipe heat exchanger with latent heat storage is experimentally studied. The experimental results show that the device may operate under either the fluid to fluid heat transfer with charging heat to the phase change material (PCM) or the fluid to fluid heat transfer with discharging heat from the PCM modes according to the initial temperature of the PCM. The melting/solidification curves, the performances of the heat pipes and the device, the influences of the inlet temperature and the mass flow rate of the cold water on the operation performance are investigated by extensive experiments. The experimental results also disclose that under the simultaneous charging/discharging operation mode, although the heat transfer from the hot water directly to the cold water may vary, it always takes up a major part of the total heat recovered by the cold water due to the very small thermal resistance compared with the thermal resistance of the PCM side. The melting/solidification processes taking place in the simultaneous charging/discharging operation are compared with those in the charging only and discharging only processes. By applying a simplified thermal resistance analysis, a criterion for predicting the exact operation modes was derived and used to explain the observed experimental phenomena

A cross-sectional analysis of variation in charges and prices across California for percutaneous coronary intervention.

Directory of Open Access Journals (Sweden)

Renee Y Hsia

Full Text Available Though past studies have shown wide variation in aggregate hospital price indices and specific procedures, few have documented or explained such variation for distinct and common episodes of care.We sought to examine the variability in charges for percutaneous coronary intervention (PCI with a drug-eluting stent and without major complications (MS-DRG-247, and determine whether hospital and market characteristics influenced these charges.We conducted a cross-sectional analysis of adults admitted to California hospitals in 2011 for MS-DRG-247 using patient discharge data from the California Office of Statewide Health Planning and Development. We used a two-part linear regression model to first estimate hospital-specific charges adjusted for patient characteristics, and then examine whether the between-hospital variation in those estimated charges was explained by hospital and market characteristics.Adjusted charges for the average California patient admitted for uncomplicated PCI ranged from $22,047 to $165,386 (median: $88,350 depending on which hospital the patient visited. Hospitals in areas with the highest cost of living, those in rural areas, and those with more Medicare patients had higher charges, while government-owned hospitals charged less. Overall, our model explained 43% of the variation in adjusted charges. Estimated discounted prices paid by private insurers ranged from $3,421 to $80,903 (median: $28,571.Charges and estimated discounted prices vary widely between hospitals for the average California patient undergoing PCI without major complications, a common and relatively homogeneous episode of care. Though observable hospital characteristics account for some of this variation, the majority remains unexplained.

The influence of hydrogen intercalation on inner pressure of Ni/MH battery during fast charge

Science.gov (United States)

Shi, Jianzhen; Wu, Feng; Hu, Daozhong; Chen, Shi; Mao, Licai; Wang, Guoqing

Gaseous hydrogen is confirmed to be the main component and primarily responsible for the inner pressure rise inside the 8-Ah Ni/MH batteries during fast charge. Based on a temperature-dependent pressure model proposed in this work, the kinetic characteristics of the hydrogen evolution were investigated. The overpotential and exchange current density were obtained by fitting the presented equation to the experimental data. Moreover, the profiles of hydrogen concentration during fast charge was further modeled and calculated according to the proposed mathematical model of hydrogen intercalation. It is indicated that diffusion step controls the fast charge performances and the higher the charge rate is, the more quickly the negative electrode attains to the maximum surface intercalation fraction, and however, the calculated results also show that further charge can reduce the difference of charge efficiency among the various rate during fast charge. Numerical investigations also reveal that the increase of diffusion coefficient and decrease of the particle size can efficiently improve the characteristics of fast charge, respectively.

The characteristics of charged α card method and its use in uranium prospecting

International Nuclear Information System (INIS)

Hua Rongzhou; Ge Jingxia.

1985-01-01

The charged α card method is a relatively new technique for uranium prospecting, which is based on the detection of radon. This paper discusses the fundamental theory of charged α card and the field orientation survey. The relation between radon in the detection cup and α activity on the α card has been calculated. The results of field and laboratory experiments are provided. It is concluded that the method described is more sensitive and more effective for uranium prospecting than the α card method

Non-Markovian dynamics of dust charge fluctuations in dusty plasmas

Science.gov (United States)

Asgari, H.; Muniandy, S. V.; Ghalee, Amir; Ghalee

2014-06-01

Dust charge fluctuates even in steady-state uniform plasma due to the discrete nature of the charge carriers and can be described using standard Langevin equation. In this work, two possible approaches in order to introduce the memory effect in dust charging dynamics are proposed. The first part of the paper provides the generalization form of the fluctuation-dissipation relation for non-Markovian systems based on generalized Langevin equations to determine the amplitudes of the dust charge fluctuations for two different kinds of colored noises under the assumption that the fluctuation-dissipation relation is valid. In the second part of the paper, aiming for dusty plasma system out of equilibrium, the fractionalized Langevin equation is used to derive the temporal two-point correlation function of grain charge fluctuations which is shown to be non-stationary due to the dependence on both times and not the time difference. The correlation function is used to derive the amplitude of fluctuations for early transient time.

Model for thickness dependence of radiation charging in MOS structures

Science.gov (United States)

Viswanathan, C. R.; Maserjian, J.

1976-01-01

The model considers charge buildup in MOS structures due to hole trapping in the oxide and the creation of sheet charge at the silicon interface. The contribution of hole trapping causes the flatband voltage to increase with thickness in a manner in which square and cube dependences are limiting cases. Experimental measurements on samples covering a 200 - 1000 A range of oxide thickness are consistent with the model, using independently obtained values of hole-trapping parameters. An important finding of our experimental results is that a negative interface charge contribution due to surface states created during irradiation compensates most of the positive charge in the oxide at flatband. The tendency of the surface states to 'track' the positive charge buildup in the oxide, for all thicknesses, applies both in creation during irradiation and in annihilation during annealing. An explanation is proposed based on the common defect origin of hole traps and potential surface states.

Transport of electric charge in insulators

International Nuclear Information System (INIS)

Lopez C, E.

1979-01-01

In this work a review is made of important concepts in the study of the transport of electric charge in insulators. These concepts are: electrical contacts, transport regimes as viewed in the I-V characteristics, and photoinjection processes by internal photemission of holes or electrons from metals or semiconductors into insulators or by a virtual electrode using strongly absorbed light. Experimental results of photoinjection of holes and electrons into sulfur single crystals are analyzed using these concepts. The observation of the Mott-Gurney transition is reported for the first time. This is the transition between the region of space charge limited currents (SCLC) and the region of saturation of the current as a function of the applied voltage. A modified Mott-Gurney theoretical model is presented that is able to explain the whole I-V characteristic for uv and the internal photoemission of hopes and uv photoinjection of electrons. For the case of internal photoemission of electrons the conventional space charge limited current theory for an exponential distribution of traps is able to explain the experimental data. It is found that the crystals are of high purity since the total density of traps, as calculated from their exponential distribution, is Nsub(t) equals 1.8 X 10 14 cm -3 . (author)

Charge-spin-orbital dynamics of one-dimensional two-orbital Hubbard model

Energy Technology Data Exchange (ETDEWEB)

Onishi, Hiroaki [Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)

2010-01-15

We study the real-time evolution of a charge-excited state in a one-dimensional e{sub g}-orbital degenerate Hubbard model, by a time-dependent density-matrix renormalization group method. Considering a chain along the z direction, electrons hop between adjacent 3z{sup 2}-r{sup 2} orbitals, while x{sup 2}-y{sup 2} orbitals are localized. For the charge-excited state, a holon-doublon pair is introduced into the ground state at quarter filling. At initial time, there is no electron in a holon site, while a pair of electrons occupies 3z{sup 2}-r{sup 2} orbital in a doublon site. As the time evolves, the holon motion is governed by the nearest-neighbor hopping, but the electron pair can transfer between 3z{sup 2}-r{sup 2} orbital and x{sup 2}-y{sup 2} orbital through the pair hopping in addition to the nearest-neighbor hopping. Thus holon and doublon propagate at different speed due to the pair hopping that is characteristic of multi-orbital systems.

Nanofibre production in spiders without electric charge.

Science.gov (United States)

Joel, Anna-Christin; Baumgartner, Werner

2017-06-15

Technical nanofibre production is linked to high voltage, because nanofibres are typically produced by electrospinning. In contrast, spiders have evolved a way to produce nanofibres without high voltage. These spiders are called cribellate spiders and produce nanofibres within their capture thread production. It is suggested that their nanofibres become frictionally charged when brushed over a continuous area on the calamistrum, a comb-like structure at the metatarsus of the fourth leg. Although there are indications that electrostatic charges are involved in the formation of the thread structure, final proof is missing. We proposed three requirements to validate this hypothesis: (1) the removal of any charge during or after thread production has an influence on the structure of the thread; (2) the characteristic structure of the thread can be regenerated by charging; and (3) the thread is attracted to or repelled from differently charged objects. None of these three requirements were proven true. Furthermore, mathematical calculations reveal that even at low charges, the calculated structural assembly of the thread does not match the observed reality. Electrostatic forces are therefore not involved in the production of cribellate capture threads. © 2017. Published by The Company of Biologists Ltd.

Space Charge Modulated Electrical Breakdown of Oil Impregnated Paper Insulation Subjected to AC-DC Combined Voltages

Directory of Open Access Journals (Sweden)

Yuanwei Zhu

2018-06-01

Full Text Available Based on the existing acknowledgment that space charge modulates AC and DC breakdown of insulating materials, this investigation promotes the related investigation into the situations of more complex electrical stress, i.e., AC-DC combined voltages. Experimentally, the AC-DC breakdown characteristics of oil impregnated paper insulation were systematically investigated. The effects of pre-applied voltage waveform, AC component ratio, and sample thickness on AC-DC breakdown characteristics were analyzed. After that, based on an improved bipolar charge transport model, the space charge profiles and the space charge induced electric field distortion during AC-DC breakdown were numerically simulated to explain the differences in breakdown characteristics between the pre-applied AC and pre-applied DC methods under AC-DC combined voltages. It is concluded that large amounts of homo-charges are accumulated during AC-DC breakdown, which results in significantly distorted inner electric field, leading to variations of breakdown characteristics of oil impregnated paper insulation. Therefore, space charges under AC-DC combined voltages must be considered in the design of converter transformers. In addition, this investigation could provide supporting breakdown data for insulation design of converter transformers and could promote better understanding on the breakdown mechanism of insulating materials subjected to AC-DC combined voltages.

Thunderstorm Charge Structures Producing Negative Gigantic Jets

Science.gov (United States)

Boggs, L.; Liu, N.; Riousset, J. A.; Shi, F.; Rassoul, H.

2016-12-01

Here we present observational and modeling results that provide insight into thunderstorm charge structures that produce gigantic jet discharges. The observational results include data from four different thunderstorms producing 9 negative gigantic jets from 2010 to 2014. We used radar, very high frequency (VHF) and low frequency (LF) lightning data to analyze the storm characteristics, charge structures, and lightning activity when the gigantic jets emerged from the parent thunderstorms. A detailed investigation of the evolution of one of the charge structures by analyzing the VHF data is also presented. The newly found charge structure obtained from the observations was analyzed with fractal modeling and compared with previous fractal modeling studies [Krehbiel et al., Nat. Geosci., 1, 233-237, 2008; Riousset et al., JGR, 115, A00E10, 2010] of gigantic jet discharges. Our work finds that for normal polarity thunderstorms, gigantic jet charge structures feature a narrow upper positive charge region over a wide middle negative charge region. There also likely exists a `ring' of negative screening charge located around the perimeter of the upper positive charge. This is different from previously thought charge structures of the storms producing gigantic jets, which had a very wide upper positive charge region over a wide middle negative charge region, with a very small negative screening layer covering the cloud top. The newly found charge structure results in leader discharge trees in the fractal simulations that closely match the parent flashes of gigantic jets inside and outside the thundercloud. The previously used charge structures, while vital to the understanding of gigantic jet initiation and the role of charge imbalances inside the cloud, do not produce leader discharge trees that agree with observed gigantic jet discharges.Finally, the newly discovered gigantic jet charge structures are formed near the end of a convective pulse [Meyer et al., JGR, 118

Longitudinal Space Charge in the SPS

CERN Document Server

Lasheen, Alexandre

2016-01-01

Longitudinal instabilities due to the SPS beam coupling impedance are a major issue for future projects and it is essential to have an accurate SPS impedance model to study them. The longitudinal space charge effect can be modelled by a pure reactive impedance and should also be included in simulations as it may have an impact at low energy. In this Note, the effect of the longitudinal space charge in the SPS is evaluated by taking into account the variation of the transverse beam size and vacuum chamber geometry along the ring. Scaling laws are used to investigate what are the most important parameters for the evaluation of the longitudinal space charge impedance.

Space-Charge Experiments at the CERN Proton Synchrotron

CERN Document Server

Franchetti, Giuliano; Hofmann, I; Martini, M; Métral, E; Qiang, J; Ryne, D; Steerenberg, R; CFA Beam Dynamics Workshop “High Intensity and Brightness Hadron Beams”

2005-01-01

Benchmarking of the simulation codes used for the design of the next generation of high beam power accelerators is of paramount importance due to the very demanding requirements on the level of beam losses. This is usually accomplished by comparing simulation results against available theories, and more importantly, against experimental observations. To this aim, a number of well-defined test cases, obtained by accurate measurements made in existing machines, are of great interest. Such measurements have been made in the CERN Proton Synchrotron to probe three space-charge effects: (i) transverse emittance blow-up due to space-charge induced crossing of the integer or half-integer stop-band, (ii) space-charge and octupole driven resonance trapping, and (iii) intensity-dependent emittance transfer between the two transverse planes. The last mechanism is discussed in detail in this paper and compared to simulation predictions.

Emissions-critical charge cooling using an organic rankine cycle

Science.gov (United States)

Ernst, Timothy C.; Nelson, Christopher R.

2014-07-15

The disclosure provides a system including a Rankine power cycle cooling subsystem providing emissions-critical charge cooling of an input charge flow. The system includes a boiler fluidly coupled to the input charge flow, an energy conversion device fluidly coupled to the boiler, a condenser fluidly coupled to the energy conversion device, a pump fluidly coupled to the condenser and the boiler, an adjuster that adjusts at least one parameter of the Rankine power cycle subsystem to change a temperature of the input charge exiting the boiler, and a sensor adapted to sense a temperature characteristic of the vaporized input charge. The system includes a controller that can determine a target temperature of the input charge sufficient to meet or exceed predetermined target emissions and cause the adjuster to adjust at least one parameter of the Rankine power cycle to achieve the predetermined target emissions.

Homogeneous Charge Compression Ignition Combustion of Dimethyl Ether

DEFF Research Database (Denmark)

Pedersen, Troels Dyhr

This thesis is based on experimental and numerical studies on the use of dimethyl ether (DME) in the homogeneous charge compression ignition (HCCI) combustion process. The first paper in this thesis was published in 2007 and describes HCCI combustion of pure DME in a small diesel engine. The tests...... were designed to investigate the effect of engine speed, compression ratio and equivalence ratio on the combustion timing and the engine performance. It was found that the required compression ratio depended on the equivalence ratio used. A lower equivalence ratio requires a higher compression ratio...... before the fuel is burned completely, due to lower in-cylinder temperatures and lower reaction rates. The study provided some insight in the importance of operating at the correct compression ratio, as well as the operational limitations and emission characteristics of HCCI combustion. HCCI combustion...

Tunneling Characteristics Depending on Schottky Barriers and Diffusion Current in SiOC.

Science.gov (United States)

Oh, Teresa; Kim, Chy Hyung

2016-02-01

To obtain a diffusion current in SiOC, the aluminum doped zinc oxide films were deposited on SiOC/Si wafer by a RF magnetron sputtering. All the X-ray patterns of the SiOC films showed amorphous phases. The level of binding energy of Si atoms will lead to an additional potential modulation by long range Coulombic and covalent interactions with oxygen ions. The growth of the AZO film was affected by the characteristics of SiOC, resulting in similar trends in XPS spectra and a shift to higher AZO lattice d values than the original AZO d values in XRD analyses. The charges trapped by the defects at the interlayer between AZO and SiOC films induced the decreased mobility of carriers. In the absence of trap charges, AZO grown on SiOC film such as the sample prepared at O2 = 25 or 30 sccm, which has low charge carrier concentration and high mobility, showed high mobility in an ambipolar characteristic of oxide semiconductor due to the tunneling effect and diffusion current. The structural matching of an interface between AZO and amorphous SiOC enhanced the height of Schottky Barrier (SB), and then the mobility was increased by the tunneling effect from band to band through the high SB.

Spin-Charge Separation in Finite Length Metallic Carbon Nanotubes

KAUST Repository

Zhang, Yongyou

2017-10-17

Using time-dependent density functional theory, we study the optical excitations in finite length carbon nanotubes. Evidence of spin-charge separation is given in the spacetime domain. We demonstrate that the charge density wave is due to collective excitations of electron singlets, while the accompanying spin density wave is due to those of electron triplets. The Tomonaga–Luttinger liquid parameter and density–density interaction are extrapolated from the first-principles excitation energies. We show that the density–density interaction increases with the length of the nanotube. The singlet and triplet excitation energies, on the other hand, decrease for increasing length of the nanotube. Their ratio is used to establish a first-principles approach for deriving the Tomonaga–Luttinger parameter (in excellent agreement with experimental data). Time evolution analysis of the charge and spin line densities evidences that the charge and spin density waves are elementary excitations of metallic carbon nanotubes. Their dynamics show no dependence on each other.

Dynamics of neutral and charged aerosol particles

Energy Technology Data Exchange (ETDEWEB)

Leppae, J.

2012-07-01

Atmospheric aerosol particles have various climate effects and adverse health effects, which both depend on the size and number concentration of the particles. Freshly-formed particles are not large enough to impact neither health nor climate and they are most susceptible to removal by collisions with larger pre-existing particles. Consequently, the knowledge of both the formation and the growth rate of particles are crucially important when assessing the health and climate effects of atmospheric new particle formation. The purpose of this thesis is to increase our knowledge of the dynamics of neutral and charged aerosol particles with a specific interest towards the particle growth rate and processes affecting the aerosol charging state. A new model, Ion-UHMA, which simulates the dynamics of neutral and charged particles, was developed for this purpose. Simple analytical formulae that can be used to estimate the growth rate due to various processes were derived and used to study the effects of charged particles on the growth rate. It was found that the growth rate of a freshly-formed particle population due to condensation and coagulation could be significantly increased when a considerable fraction of the particles are charged. Finally, recent data-analysis methods that have been applied to the aerosol charging states obtained from the measurements were modified for a charge asymmetric framework. The methods were then tested on data obtained from aerosol dynamics simulations. The methods were found to be able to provide reasonable estimates on the growth rate and proportion of particles formed via ion-induced nucleation, provided that the growth rate is high enough and that the charged particles do not grow much more rapidly than the neutral ones. A simple procedure for estimating whether the methods are suitable for analysing data obtained in specific conditions was provided. In this thesis, the dynamics of neutral and charged aerosol particles were studied in

Performance improvement of charge-trap memory by using a stacked Zr{sub 0.46}Si{sub 0.54}O{sub 2}/Al{sub 2}O{sub 3} charge-trapping layer

Energy Technology Data Exchange (ETDEWEB)

Tang, Zhenjie; Hu, Dan; Zhang, Xiwei; Zhao, Yage [College of Physics and Electronic Engineering, Anyang Normal University, Anyang 455000 (China); Li, Rong [School of Mathematics and Statistics, Anyang Normal University, Anyang 455000 (China)

2016-11-15

The postdeposition annealing (PDA)-treated charge-trap flash memory capacitor with stacked Zr{sub 0.46}Si{sub 0.54}O{sub 2}/Al{sub 2}O{sub 3} charge-trapping layer flanked by a SiO{sub 2} tunneling oxide and an Al{sub 2}O{sub 3} blocking oxide was fabricated and investigated. It is observed that the memory capacitor exhibits prominent memory characteristics with large memory windows 12.8 V in a ±10 V gate sweeping voltage range, faster program/erase speed, and good data-retention characteristics even at 125 C compared to a single charge-trapping layer (Zr{sub 0.46}Si{sub 0.54}O{sub 2}, Zr{sub 0.79}Si{sub 0.21}O{sub 2}, and Zr{sub 0.46}Al{sub 1.08}O{sub 2.54}). The quantum wells and introduced interfacial traps of the stacked trapping layer regulate the storage and loss behavior of charges, and jointly contribute to the improved memory characteristics. Hence, the memory capacitor with a stacked trapping layer is a promising candidate in future nonvolatile charge-trap memory device design and application. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Effective charge of energetic ions in metals

International Nuclear Information System (INIS)

Kitagawa, M.; Brandt, W.

1983-01-01

The effective charge of energetic ion, as derived from stopping power of metals, is calculated by use of a dielectronic-response function method. The electronic distribution in the ion is described through the variational principle in a statistical approximation. The dependences of effective charge on the ion velocity, atomic number and r/sub s/-value of metal are derived at the low-velocity region. The effective charge becomes larger than the real charge of ion due to the close collisions. We obtain the quasi-universal equation of the fractional effective electron number of ion as a function of the ratio between the ionic size and the minimum distance approach. The comparsion between theoretical and experimental results of the effective charge is performed for the cases of N ion into Au, C and Al. We also discuss the equipartition rule of partially ionized ion at the high-velocity region

Experimental study of combustion and emission characteristics of ethanol fuelled port injected homogeneous charge compression ignition (HCCI) combustion engine

Energy Technology Data Exchange (ETDEWEB)

Maurya, Rakesh Kumar; Agarwal, Avinash Kumar [Engine Research Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208 016 (India)

2011-04-15

The homogeneous charge compression ignition (HCCI) is an alternative combustion concept for in reciprocating engines. The HCCI combustion engine offers significant benefits in terms of its high efficiency and ultra low emissions. In this investigation, port injection technique is used for preparing homogeneous charge. The combustion and emission characteristics of a HCCI engine fuelled with ethanol were investigated on a modified two-cylinder, four-stroke engine. The experiment is conducted with varying intake air temperature (120-150 C) and at different air-fuel ratios, for which stable HCCI combustion is achieved. In-cylinder pressure, heat release analysis and exhaust emission measurements were employed for combustion diagnostics. In this study, effect of intake air temperature on combustion parameters, thermal efficiency, combustion efficiency and emissions in HCCI combustion engine is analyzed and discussed in detail. The experimental results indicate that the air-fuel ratio and intake air temperature have significant effect on the maximum in-cylinder pressure and its position, gas exchange efficiency, thermal efficiency, combustion efficiency, maximum rate of pressure rise and the heat release rate. Results show that for all stable operation points, NO{sub x} emissions are lower than 10 ppm however HC and CO emissions are higher. (author)

Quasiparticle conductance-voltage characteristics for break junctions involving d-wave superconductors: charge-density-wave effects.

Science.gov (United States)

Ekino, T; Gabovich, A M; Suan Li, Mai; Szymczak, H; Voitenko, A I

2017-12-20

Quasiparticle tunnel conductance-voltage characteristics (CVCs), [Formula: see text], were calculated for break junctions (BJs) made up of layered d-wave superconductors partially gapped by charge-density waves (CDWs). The current is assumed to flow in the ab-plane of electrodes. The influence of CDWs is analyzed by comparing the resulting CVCs with CVCs calculated for BJs made up of pure d-wave superconductors with relevant parameters. The main CDW-effects were found to be the appearance of new CVC peculiarities and the loss of CVC symmetry with respect to the V-sign. Tunnel directionality was shown to be one of the key factors in the formation of [Formula: see text] dependences. In particular, the orientation of electrodes with respect to the current channel becomes very important. As a result, [Formula: see text] can acquire a large variety of forms similar to those for tunnel junctions between superconductors with s-wave, d-wave, and mixed symmetry of their order parameters. The diversity of peculiarities is especially striking at finite temperatures. In the case of BJs made up of pure d-wave superconductors, the resulting CVC can include a two-peak gap-driven structure. The results were compared with the experimental BJ data for a number of high-T c oxides. It was shown that the large variety of the observed current-voltage characteristics can be interpreted in the framework of our approach. Thus, quasiparticle tunnel currents in the ab-plane can be used as an additional mean to detect CDWs competing with superconductivity in cuprates or other layered superconductors.

Charge degeneracy removal in the screened hydrogen atom

International Nuclear Information System (INIS)

Penna, Andre L A; Diniz, Joao B; Oliveira, Fernando A

2009-01-01

We derive an analytical model for the states of the screened hydrogen atom by using a new charge degeneracy removal approach. Starting from the nonzero Thomas-Fermi parameter q, we show that screening effect is due to breaks of the charge degeneracy in each quantum level of the hydrogen atom. The charge degeneracy removal reparametrizes the atomic system through the effective nuclear charge α n,l and the appearance of a dual charge γ n,l for each quantum level. In this approach, we show that the screening of a quantum state depends hierarchically on the screening from all previous quantum states with the same angular quantum numbers. The excited state energies E n,l (q) are analytically found taking into account the contribution of this new charge degeneracy for each quantum level. Finally, we also have estimated accurate critical screening parameters q* n,l for the bound-unbound transition.

Modeling charge transport properties of cyano-substituted PPV

International Nuclear Information System (INIS)

Correia, Helena M.G.; Ramos, Marta M.D.

2003-01-01

In recent years, poly (p-phenylenevinylene) (PPV) and its derivatives have attracted much interest due to their applications in light-emitting diodes (LEDs). One of the issues that determine device performance is the transport of charge carriers along the polymer strands. For that reason, we investigate the influence of cyano substitution on geometry and electronic behaviour of PPV chains using self-consistent quantum molecular dynamics simulations. Our results suggest that substitution by cyano groups induce distortion in the PPV chains and a charge rearrangement among the polymer atoms. Specifically addressed is the issue concerning estimates of charge (electron and hole) mobility by computer experiments. Significant differences have been found both in the strength of the electric field needed to move positive and negative charge carriers along the polymer chain as well as in charge mobility

Space-charge calculations in synchrotrons

Energy Technology Data Exchange (ETDEWEB)

Machida, S.

1993-05-01

One obvious bottleneck of achieving high luminosity in hadron colliders, such as the Superconducting Super Collider (SSC), is the beam emittance growth, due to space-charge effects in low energy injector synchrotrons. Although space-charge effects have been recognized since the alternating-gradient synchrotron was invented, and the Laslett tune shift usually calculated to quantify these effects, our understanding of the effects is limited, especially when the Laslett tune shift becomes a large fraction of the integer. Using the Simpsons tracking code, which we developed to study emittance preservation issues in proton synchrotrons, we investigated space-charge effects in the SSC Low Energy Booster (LEB). We observed detailed dependence on parameters such as beam intensity, initial emittance, injection energy, lattice function, and longitudinal motion. A summary of those findings, as well as the tracking technique we developed for the study, are presented.

Aspirin degradation in surface-charged TEMPO-oxidized mesoporous crystalline nanocellulose.

Science.gov (United States)

Carlsson, Daniel O; Hua, Kai; Forsgren, Johan; Mihranyan, Albert

2014-01-30

TEMPO-mediated surface oxidation of mesoporous highly crystalline Cladophora cellulose was used to introduce negative surface charges onto cellulose nanofibrils without significantly altering other structural characteristics. This enabled the investigation of the influence of mesoporous nanocellulose surface charges on aspirin chemical stability to be conducted. The negative surface charges (carboxylate content 0.44±0.01 mmol/g) introduced on the mesoporous crystalline nanocellulose significantly accelerated aspirin degradation, compared to the starting material which had significantly less surface charge (0.06±0.01 mmol/g). This effect followed from an increased aspirin amorphisation ability in mesopores of the oxidized nanocellulose. These results highlight the importance of surface charges in formulating nanocellulose for drug delivery. Copyright © 2013 Elsevier B.V. All rights reserved.

The influence of hydrogen intercalation on inner pressure of Ni/MH battery during fast charge

Energy Technology Data Exchange (ETDEWEB)

Shi, Jianzhen; Wu, Feng; Hu, Daozhong; Chen, Shi; Mao, Licai; Wang, Guoqing [School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing 100081 (China)

2006-10-20

Gaseous hydrogen is confirmed to be the main component and primarily responsible for the inner pressure rise inside the 8-Ah Ni/MH batteries during fast charge. Based on a temperature-dependent pressure model proposed in this work, the kinetic characteristics of the hydrogen evolution were investigated. The overpotential and exchange current density were obtained by fitting the presented equation to the experimental data. Moreover, the profiles of hydrogen concentration during fast charge was further modeled and calculated according to the proposed mathematical model of hydrogen intercalation. It is indicated that diffusion step controls the fast charge performances and the higher the charge rate is, the more quickly the negative electrode attains to the maximum surface intercalation fraction, and however, the calculated results also show that further charge can reduce the difference of charge efficiency among the various rate during fast charge. Numerical investigations also reveal that the increase of diffusion coefficient and decrease of the particle size can efficiently improve the characteristics of fast charge, respectively. (author)

Surface charge accumulation of particles containing radionuclides in open air.

Science.gov (United States)

Kim, Yong-Ha; Yiacoumi, Sotira; Tsouris, Costas

2015-05-01

Radioactivity can induce charge accumulation on radioactive particles. However, electrostatic interactions caused by radioactivity are typically neglected in transport modeling of radioactive plumes because it is assumed that ionizing radiation leads to charge neutralization. The assumption that electrostatic interactions caused by radioactivity are negligible is evaluated here by examining charge accumulation and neutralization on particles containing radionuclides in open air. A charge-balance model is employed to predict charge accumulation on radioactive particles. It is shown that particles containing short-lived radionuclides can be charged with multiple elementary charges through radioactive decay. The presence of radioactive particles can significantly modify the particle charge distribution in open air and yield an asymmetric bimodal charge distribution, suggesting that strong electrostatic particle interactions may occur during short- and long-range transport of radioactive particles. Possible effects of transported radioactive particles on electrical properties of the local atmosphere are reported. The study offers insight into transport characteristics of airborne radionuclides. Results are useful in atmospheric transport modeling of radioactive plumes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Optimal control of an electric vehicle’s charging schedule under electricity markets

DEFF Research Database (Denmark)

Lan, Tian; Hu, Junjie; Kang, Qi

2013-01-01

As increasing numbers of electric vehicles (EVs) enter into the society, the charging behavior of EVs has got lots of attention due to its economical difference within the electricity market. The charging cost for EVs generally differ from each other in choosing the charging time interval (hourly...

Charging performance of automotive batteries-An underestimated factor influencing lifetime and reliable battery operation

Science.gov (United States)

Sauer, Dirk Uwe; Karden, Eckhard; Fricke, Birger; Blanke, Holger; Thele, Marc; Bohlen, Oliver; Schiffer, Julia; Gerschler, Jochen Bernhard; Kaiser, Rudi

Dynamic charge acceptance and charge acceptance under constant voltage charging conditions are for two reasons essential for lead-acid battery operation: energy efficiency in applications with limited charging time (e.g. PV systems or regenerative braking in vehicles) and avoidance of accelerated ageing due to sulphation. Laboratory tests often use charge regimes which are beneficial for the battery life, but which differ significantly from the operating conditions in the field. Lead-acid batteries in applications with limited charging time and partial-state-of-charge operation are rarely fully charged due to their limited charge acceptance. Therefore, they suffer from sulphation and early capacity loss. However, when appropriate charging strategies are applied most of the lost capacity and thus performance for the user may be recovered. The paper presents several aspects of charging regimes and charge acceptance. Theoretical and experimental investigations show that temperature is the most critical parameter. Full charging within short times can be achieved only at elevated temperatures. A strong dependency of the charge acceptance during charging pulses on the pre-treatment of the battery can be observed, which is not yet fully understood. But these effects have a significant impact on the fuel efficiency of micro-hybrid electric vehicles.

Nature’s Particulate Matter with and without Charge and Travelling

NARCIS (Netherlands)

Ursem, W.N.J.

2016-01-01

Natures and anthropogenic particulates can travel long distances on wind flows, but negative electrical charge due to friction can increase dispersion. Models for calculations of distance travelling of biological particulate matter with and without charge are never been calculated in a theoretical

On the theoretical description of weakly charged surfaces.

Science.gov (United States)

Wang, Rui; Wang, Zhen-Gang

2015-03-14

It is widely accepted that the Poisson-Boltzmann (PB) theory provides a valid description for charged surfaces in the so-called weak coupling limit. Here, we show that the image charge repulsion creates a depletion boundary layer that cannot be captured by a regular perturbation approach. The correct weak-coupling theory must include the self-energy of the ion due to the image charge interaction. The image force qualitatively alters the double layer structure and properties, and gives rise to many non-PB effects, such as nonmonotonic dependence of the surface energy on concentration and charge inversion. In the presence of dielectric discontinuity, there is no limiting condition for which the PB theory is valid.

Improved charge trapping properties by embedded graphene oxide quantum-dots for flash memory application

Science.gov (United States)

Jia, Xinlei; Yan, Xiaobing; Wang, Hong; Yang, Tao; Zhou, Zhenyu; Zhao, Jianhui

2018-06-01

In this work, we have investigated two kinds of charge trapping memory devices with Pd/Al2O3/ZnO/SiO2/p-Si and Pd/Al2O3/ZnO/graphene oxide quantum-dots (GOQDs)/ZnO/SiO2/p-Si structure. Compared with the single ZnO sample, the memory window of the ZnO-GOQDs-ZnO sample reaches a larger value (more than doubled) of 2.7 V under the sweeping gate voltage ± 7 V, indicating a better charge storage capability and the significant charge trapping effects by embedding the GOQDs trapping layer. The ZnO-GOQDs-ZnO devices have better date retention properties with the high and low capacitances loss of ˜ 1.1 and ˜ 6.9%, respectively, as well as planar density of the trapped charges of 1.48 × 1012 cm- 2. It is proposed that the GOQDs play an important role in the outstanding memory characteristics due to the deep quantum potential wells and the discrete distribution of the GOQDs. The long date retention time might have resulted from the high potential barrier which suppressed both the back tunneling and the leakage current. Intercalating GOQDs in the memory device is a promising method to realize large memory window, low-power consumption and excellent retention properties.

Highly charged ion trapping and cooling

International Nuclear Information System (INIS)

Beck, B. R.; Church, D. A.; Gruber, L.; Holder, J. P.; Schneider, D.; Steiger, J.

1998-01-01

In the past few years a cryogenic Penning trap (RETRAP) has been operational at the Electron Beam Ion Trap (EBIT) facility at Lawrence Livermore National Laboratory. The combination of RETRAP and EBIT provides a unique possibility of producing and re-trapping highly charged ions and cooling them to very low temperatures. Due to the high Coulomb potentials in such an ensemble of cold highly charged ions the Coulomb coupling parameter (the ratio of Coulomb potential to the thermal energy) can easily reach values of 172 and more. To study such systems is not only of interest in astrophysics to simulate White Dwarf star interiors but opens up new possibilities in a variety of areas (e.g. laser spectroscopy), cold highly charged ion beams

Charge-field formulation of quantum electrodynamics (QEMED)

International Nuclear Information System (INIS)

Leiter, D.

1980-01-01

By expressing classical electron theory in terms of 'charge-field' functional structures, it is shown that a finite formulation of the classical electrodynamics of point charges emerges in a simple and elegant fashion. This is used to construct a 'charge-field' quantum electrodynamic theory. It is found that interacting photon states are generated as a secondary manifestation of electron-positron quantization, and do not require the usual 'free' canonical quantization scheme. The possibility is discussed that this approach may lead to a better formulation of quantum electrodynamics in the Heisenberg picture and suggests a crucial experimental test to distinguish this new 'charge-field' quantum electrodynamics 'QEMED' from the standard QED formulation. Specifically QEMED predicts that the 'Einstein principle of separability' should be found to be valid for correlated photon polarization measurements, in which the polarizers are changed more rapidly than a characteristic photon travel time. Such an experiment (Aspect 1976) can distinguish between QEMED and QED in a complete and clear-cut fashion. (U.K.)

A relativistic self-consistent model for studying enhancement of space charge limited emission due to counter-streaming ions

Science.gov (United States)

Lin, M. C.; Verboncoeur, J.

2016-10-01

A maximum electron current transmitted through a planar diode gap is limited by space charge of electrons dwelling across the gap region, the so called space charge limited (SCL) emission. By introducing a counter-streaming ion flow to neutralize the electron charge density, the SCL emission can be dramatically raised, so electron current transmission gets enhanced. In this work, we have developed a relativistic self-consistent model for studying the enhancement of maximum transmission by a counter-streaming ion current. The maximum enhancement is found when the ion effect is saturated, as shown analytically. The solutions in non-relativistic, intermediate, and ultra-relativistic regimes are obtained and verified with 1-D particle-in-cell simulations. This self-consistent model is general and can also serve as a comparison for verification of simulation codes, as well as extension to higher dimensions.

Enhanced memory performance by tailoring the microstructural evolution of (ZrO{sub 2}){sub 0.6}(SiO{sub 2}){sub 0.4} charge trapping layer in the nanocrystallites-based charge trap flash memory cells

Energy Technology Data Exchange (ETDEWEB)

Tang, Zhenjie; Xu, Hanni; Xia, Yidong; Yin, Jiang; Li, Aidong; Liu, Zhiguo [Nanjing University, Department of Materials Science and Engineering and National Laboratory of Solid State Microstructures, Nanjing (China); Zhu, Xinhua [Nanjing University, Department of Physics and National and Laboratory of Solid State Microstructures, Nanjing (China); Yan, Feng [Nanjing University, School of Electronics Science and Engineering, Nanjing (China)

2012-07-15

ZrO{sub 2} nanocrystallites based charge trap memory cells by incorporating a (ZrO{sub 2}){sub 0.6}(SiO{sub 2}){sub 0.4} film as a charge trapping layer and amorphous Al{sub 2}O{sub 3} as tunneling and blocking layer were prepared and investigated. The precipitation reaction in charge trapping layer forming ZrO{sub 2} nanocrystallites during rapid thermal annealing was investigated by transmission electron microscopy. The density and size of ZrO{sub 2} nanocrystallites are the critical factors for controlling the charge storage characteristics. The ZrO{sub 2} nanocrystallites based memory cells after postannealing at 800 C for 60 s exhibit the best electrical characteristics and a low charge loss {proportional_to}5 % after 10{sup 5} write/erase cycles operation. (orig.)

Charge-coupled-device X-ray detector performance model

Science.gov (United States)

Bautz, M. W.; Berman, G. E.; Doty, J. P.; Ricker, G. R.

1987-01-01

A model that predicts the performance characteristics of CCD detectors being developed for use in X-ray imaging is presented. The model accounts for the interactions of both X-rays and charged particles with the CCD and simulates the transport and loss of charge in the detector. Predicted performance parameters include detective and net quantum efficiencies, split-event probability, and a parameter characterizing the effective thickness presented by the detector to cosmic-ray protons. The predicted performance of two CCDs of different epitaxial layer thicknesses is compared. The model predicts that in each device incomplete recovery of the charge liberated by a photon of energy between 0.1 and 10 keV is very likely to be accompanied by charge splitting between adjacent pixels. The implications of the model predictions for CCD data processing algorithms are briefly discussed.

Minimization of power consumption during charging of superconducting accelerating cavities

Energy Technology Data Exchange (ETDEWEB)

Bhattacharyya, Anirban Krishna, E-mail: anirban.bhattacharyya@physics.uu.se; Ziemann, Volker; Ruber, Roger; Goryashko, Vitaliy

2015-11-21

The radio frequency cavities, used to accelerate charged particle beams, need to be charged to their nominal voltage after which the beam can be injected into them. The standard procedure for such cavity filling is to use a step charging profile. However, during initial stages of such a filling process a substantial amount of the total energy is wasted in reflection for superconducting cavities because of their extremely narrow bandwidth. The paper presents a novel strategy to charge cavities, which reduces total energy reflection. We use variational calculus to obtain analytical expression for the optimal charging profile. Energies, reflected and required, and generator peak power are also compared between the charging schemes and practical aspects (saturation, efficiency and gain characteristics) of power sources (tetrodes, IOTs and solid state power amplifiers) are also considered and analysed. The paper presents a methodology to successfully identify the optimal charging scheme for different power sources to minimize total energy requirement.

Minimization of power consumption during charging of superconducting accelerating cavities

International Nuclear Information System (INIS)

Bhattacharyya, Anirban Krishna; Ziemann, Volker; Ruber, Roger; Goryashko, Vitaliy

2015-01-01

The radio frequency cavities, used to accelerate charged particle beams, need to be charged to their nominal voltage after which the beam can be injected into them. The standard procedure for such cavity filling is to use a step charging profile. However, during initial stages of such a filling process a substantial amount of the total energy is wasted in reflection for superconducting cavities because of their extremely narrow bandwidth. The paper presents a novel strategy to charge cavities, which reduces total energy reflection. We use variational calculus to obtain analytical expression for the optimal charging profile. Energies, reflected and required, and generator peak power are also compared between the charging schemes and practical aspects (saturation, efficiency and gain characteristics) of power sources (tetrodes, IOTs and solid state power amplifiers) are also considered and analysed. The paper presents a methodology to successfully identify the optimal charging scheme for different power sources to minimize total energy requirement.

Structure resonances due to space charge in periodic focusing channels

Science.gov (United States)

Li, Chao; Jameson, R. A.

2018-02-01

The Vlasov-Poisson model is one of the most effective methods to study the space charge dominated beam evolution self-consistently in a periodic focusing channel. Since the approach to get the solution with this model is not trivial, previous studies are limited in degenerated conditions, either in smoothed channel (constant focusing) [I. Hofmann, Phys. Rev. E 57, 4713 (1998)] or in alternating gradient focusing channel with equal initial beam emittance condition in the degrees of freedom [I. Hofmann et al., Part. Accel. 13, 145 (1983); Chao Li et al., THOBA02, IPAC2016]. To establish a basis, we intentionally limit this article to the study of the pure transverse periodic focusing lattice with arbitrary initial beam condition, and the same lattice structure in both degrees of freedom, but with possibility of different focusing strengths. This will show the extension of the existing work. The full Hamiltonian is invoked for a pure transverse focusing lattice in various initial beam conditions, revealing different mode structure and additional modes beyond those of the degenerated cases. Application of the extended method to realistic lattices (including longitudinal accelerating elements) and further details will then reveal many new insights, and will be presented in later work.

Charge exchange cooling in the tandem mirror plasma confinement apparatus

Science.gov (United States)

Logan, B. Grant

1978-01-01

Method and apparatus for cooling a plasma of warm charged species confined in the center mirror cell of the tandem mirror apparatus by injecting cold neutral species of the plasma into at least one mirroring region of the center mirror cell, the cooling due to the loss of warm charged species through charge exchange with the cold neutral species with resulting diffusion of the warm neutral species out of the plasma.

Impurity line emission due to thermal charge exchange in JET edge plasmas

Energy Technology Data Exchange (ETDEWEB)

Maggi, C F; Horton, L D; Koenig, R; Stamp, M [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Summers, H P [Strathclyde Univ., Glasgow (United Kingdom)

1994-07-01

High n-shell emission from hydrogen-like carbon (C VI, n=8-7) has been routinely observed from the plasma edge of JET. By comparing the measured spectral line intensities with the signals predicted by advanced atomic physics modelling of carbon and hydrogen radiation, integrated with modelling of the divertor and edge plasma, it is concluded that charge transfer from excited state hydrogen donors into fully stripped carbon ions can account for the observed spectral emission, but that the hydrogen distribution and to a lesser extent the carbon distribution away from the strike zone predicted by the transport model are too low. Data presented are those of three upper X-point discharges, where the target material was carbon. 5 refs., 1 fig., 3 tabs.

Effect of Stochastic Charge Fluctuations on Dust Dynamics

Science.gov (United States)

Matthews, Lorin; Shotorban, Babak; Hyde, Truell

2017-10-01

The charging of particles in a plasma environment occurs through the collection of electrons and ions on the particle surface. Depending on the particle size and the plasma density, the standard deviation of the number of collected elementary charges, which fluctuates due to the randomness in times of collisions with electrons or ions, may be a significant fraction of the equilibrium charge. We use a discrete stochastic charging model to simulate the variations in charge across the dust surface as well as in time. The resultant asymmetric particle potentials, even for spherical grains, has a significant impact on the particle coagulation rate as well as the structure of the resulting aggregates. We compare the effects on particle collisions and growth in typical laboratory and astrophysical plasma environments. This work was supported by the National Science Foundation under Grant PHY-1414523.

New instrument for tribocharge measurement due to single particle impacts

International Nuclear Information System (INIS)

Watanabe, Hideo; Ghadiri, Mojtaba; Matsuyama, Tatsushi; Ding Yulong; Pitt, Kendal G.

2007-01-01

During particulate solid processing, particle-particle and particle-wall collisions can generate electrostatic charges. This may lead to a variety of problems ranging from fire and explosion hazards to segregation, caking, and blocking. A fundamental understanding of the particle charging in such situations is therefore essential. For this purpose we have developed a new device that can measure charge transfer due to impact between a single particle and a metal plate. The device consists of an impact test system and two sets of Faraday cage and preamplifier for charge measurement. With current amplifiers, high-resolution measurements of particle charges of approximately 1 and 10 fC have been achieved before and after the impact, respectively. The device allows charge measurements of single particles with a size as small as ∼100 μm impacting on the target at different incident angles with a velocity up to about 80 m/s. Further analyses of the charge transfer as a function of particle initial charge define an equilibrium charge, i.e., an initial charge level prior to impact for which no net charge transfer would occur as a result of impact

Surface charging, discharging and chemical modification at a sliding contact

DEFF Research Database (Denmark)

Singh, Shailendra Vikram; Kusano, Yukihiro; Morgen, Per

2012-01-01

Electrostatic charging, discharging, and consequent surface modification induced by sliding dissimilar surfaces have been studied. The surface-charge related phenomena were monitored by using a home-built capacitive, non-contact electrical probe, and the surface chemistry was studied by X...... are also able to comment on the behavior and the charge decay time in the ambient air-like condition, once the sliding contact is discontinued. XPS analysis showed a marginal deoxidation effect on the polyester disks due to the charging and discharging of the surfaces. Moreover, these XPS results clearly...

Properties of longitudinal and tpansvepse momentum characteristics of charged particles relative to the event principal axis in π+(π-)p interactions at 8 and 40 GeV/c

International Nuclear Information System (INIS)

Sartke, E.; Kanarek, T.; Koval'skj, M.; Solomin, A.N.; Kvatadze, R.A.; Shcheglova, L.M.

1983-01-01

Alterations in longitudinal and transverse momentum characteristics of charged secondaries produced in π + (π - )p interactions at 8 and 40 GeV/c are analyzed when the thrust direction of event impulse configuration is taken as the longitudinal aXis of the center-of-mass system. The usefullness of such frame is discussed

Charged black holes in phantom cosmology

Energy Technology Data Exchange (ETDEWEB)

Jamil, Mubasher; Qadir, Asghar; Rashid, Muneer Ahmad [National University of Sciences and Technology, Center for Advanced Mathematics and Physics, Rawalpindi (Pakistan)

2008-11-15

In the classical relativistic regime, the accretion of phantom-like dark energy onto a stationary black hole reduces the mass of the black hole. We have investigated the accretion of phantom energy onto a stationary charged black hole and have determined the condition under which this accretion is possible. This condition restricts the mass-to-charge ratio in a narrow range. This condition also challenges the validity of the cosmic-censorship conjecture since a naked singularity is eventually produced due to accretion of phantom energy onto black hole. (orig.)

High energy particle detectors utilizing cryogenic charge storage

Energy Technology Data Exchange (ETDEWEB)

Coon, D; Engels, E Jr; Plants, D; Shepard, P F; Yang, Y [Pittsburgh Univ., PA (USA); Sopira, M; Papania, R [Westinghouse Research and Development Labs., Monroeville, PA (USA)

1984-09-15

The mechanism of cryogenic charge storage as a method of particle detection is reviewed. A description of a simple multielement strip detector operated in this mode is given, and partial results on its operating characteristics presented.

An abnormally slow proton transfer reaction in a simple HBO derivative due to ultrafast intramolecular-charge transfer events.

Science.gov (United States)

Alarcos, Noemí; Gutierrez, Mario; Liras, Marta; Sánchez, Félix; Douhal, Abderrazzak

2015-07-07

We report on the steady-state, picosecond and femtosecond time-resolved studies of a charge and proton transfer dye 6-amino-2-(2'-hydroxyphenyl)benzoxazole (6A-HBO) and its methylated derivative 6-amino-2-(2'-methoxyphenyl)benzoxazole (6A-MBO), in different solvents. With femtosecond resolution and comparison with the photobehaviour of 6A-MBO, we demonstrate for 6A-HBO in solution, the photoproduction of an intramolecular charge-transfer (ICT) process at S1 taking place in ∼140 fs or shorter, followed by solvent relaxation in the charge transferred species. The generated structure (syn-enol charge transfer conformer) experiences an excited-state intramolecular proton-transfer (ESIPT) reaction to produce a keto-type tautomer. This subsequent proton motion occurs in 1.2 ps (n-heptane), 14 ps (DCM) and 35 ps (MeOH). In MeOH, it is assisted by the solvent molecules and occurs through tunneling for which we got a large kinetic isotope effect (KIE) of about 13. For the 6A-DBO (deuterated sample in CD3OD) the global proton-transfer reaction takes place in 200 ps, showing a remarkable slow KIE regime. The slow ESIPT reaction in DCM (14 ps), not through tunnelling as it is not sensitive to OH/OD exchange, has however to overcome an energy barrier using intramolecular as well as solvent coordinates. The rich ESIPT dynamics of 6A-HBO in the used solutions is governed by an ICT reaction, triggered by the amino group, and it is solvent dependent. Thus, the charge injection to a 6A-HBO molecular frame makes the ICT species more stable, and the phenol group less acidic, slowing down the subsequent ESIPT reaction. Our findings bring new insights into the coupling between ICT and ESIPT reactions on the potential-energy surfaces of several barriers.

The simulation of charge sharing in semiconductor X-ray pixel detectors

CERN Document Server

Mathieson, K; O'Shea, V; Passmore, M S; Rahman, M; Smith, K M; Watt, J; Whitehill, C

2002-01-01

Two simulation packages were used to model the sharing of charge, due to the scattering and diffusion of carriers, between adjacent pixel elements in semiconductors X-ray detectors. The X-ray interaction and the consequent multiple scattering was modelled with the aid of the Monte Carlo package, MCNP. The resultant deposited charge distribution was then used to create the charge cloud profile in the finite element semiconductor simulation code MEDICI. The analysis of the current pulses induced on pixel electrodes for varying photon energies was performed for a GaAs pixel detector. For a pixel pitch of 25 mu m, the charge lost to a neighbouring pixel was observed to be constant, at 0.6%, through the energies simulated. Ultimately, a fundamental limit on the pixel element size for imaging and spectroscopic devices may be set due to these key physical principles.

Charging valve of the full hydraulic braking system

Directory of Open Access Journals (Sweden)

Jinshi Chen

2016-03-01

Full Text Available It is known that the full hydraulic braking system has excellent braking performance. As the key component of the full hydraulic braking system, the parameters of the accumulator charging valve have a significant effect on the braking performance. In this article, the key parameters of the charging valve are analyzed through the static theoretical and an Advanced Modeling Environment for performing Simulation of engineering systems (AMESim simulation model of the dual-circuit accumulator charging valve is established based on the real structure parameters first. Second, according to the results of the dynamic simulation, the dynamic characteristics of the charging pressure, the flow rate, and the frequency of the charging valve are studied. The key parameters affecting the serial production are proposed and some technical advices for improving the performance of the full hydraulic system are provided. Finally, the theoretical analysis is validated by the simulation results. The comparison between the simulation results and the experimental results indicates that the simulated AMESim model of the charging valve is accurate and credible with the error rate inside 0.5% compared with the experimental result. Hence, the performance of the charging valve meets the request of the full hydraulic braking system exactly.

Combustion Characteristics of C5 Alcohols and a Skeletal Mechanism for Homogeneous Charge Compression Ignition Combustion Simulation

KAUST Repository

Park, Sungwoo

2015-10-27

C5 alcohols are considered alternative fuels because they emit less greenhouse gases and fewer harmful pollutants. In this study, the combustion characteristics of 2-methylbutanol (2-methyl-1-butanol) and isopentanol (3-methyl-1-butanol) and their mixtures with primary reference fuels (PRFs) were studied using a detailed chemical kinetic model obtained from merging previously published mechanisms. Ignition delay times of the C5 alcohol/air mixtures were compared to PRFs at 20 and 40 atm. Reaction path analyses were conducted at intermediate and high temperatures to identify the most influential reactions controlling ignition of C5 alcohols. The direct relation graph with expert knowledge methodology was used to eliminate unimportant species and reactions in the detailed mechanism, and the resulting skeletal mechanism was tested at various homogeneous charge compression ignition (HCCI) engine combustion conditions. These simulations were used to investigate the heat release characteristics of the methyl-substituted C5 alcohols, and the results show relatively strong reactions at intermediate temperatures prior to hot ignition. C5 alcohol blending in PRF75 in HCCI combustion leads to a significant decrease of low-temperature heat release (LTHR) and a delay of the main combustion. The heat release features demonstrated by C5 alcohols can be used to improve the design and operation of advanced engine technologies.

Charging of mesospheric aerosol particles: the role of photodetachment and photoionization from meteoric smoke and ice particles

Directory of Open Access Journals (Sweden)

M. Rapp

2009-06-01

Full Text Available Time constants for photodetachment, photoemission, and electron capture are considered for two classes of mesospheric aerosol particles, i.e., meteor smoke particles (MSPs and pure water ice particles. Assuming that MSPs consist of metal oxides like Fe2O3 or SiO, we find that during daytime conditions photodetachment by solar photons is up to 4 orders of magnitude faster than electron attachment such that MSPs cannot be negatively charged in the presence of sunlight. Rather, even photoemission can compete with electron capture unless the electron density becomes very large (>>1000 cm−3 such that MSPs should either be positively charged or neutral in the case of large electron densities. For pure water ice particles, however, both photodetachment and photoemission are negligible due to the wavelength characteristics of its absorption cross section and because the flux of solar photons has already dropped significantly at such short wavelengths. This means that water ice particles should normally be negatively charged. Hence, our results can readily explain the repeated observation of the coexistence of positive and negative aerosol particles in the polar summer mesopause, i.e., small MSPs should be positively charged and ice particles should be negatively charged. These results have further important implications for our understanding of the nucleation of mesospheric ice particles as well as for the interpretation of incoherent scatter radar observations of MSPs.

The purpose for GEO spacecraft deep charging and electrostatic discharging (ESD) experiment

International Nuclear Information System (INIS)

Yang Chuibai; Wang Shijin; Liang Jinbao

2005-01-01

This paper introduces the purpose for GEO spacecraft deep charging and electrostatic discharging (ESD) experiment. A method of experiment for the spacecraft deep charging and ESD aboard is proposed. Spacecraft deep charging and ESD event, frequency, energy and the level of pulse in wires due to EMP coupling into are measured. (authors)

Changes in thunderstorm characteristics due to feeder cloud merging

Science.gov (United States)

Sinkevich, Andrei A.; Krauss, Terrence W.

2014-06-01

Cumulus cloud merging is a complex dynamical and microphysical process in which two convective cells merge into a single cell. Previous radar observations and numerical simulations have shown a substantial increase in the maximum area, maximum echo top and maximum reflectivity as a result of the merging process. Although the qualitative aspects of merging have been well documented, the quantitative effects on storm properties remain less defined. Therefore, a statistical assessment of changes in storm characteristics due to merging is of importance. Further investigation into the effects of cloud merging on precipitation flux (Pflux) in a statistical manner provided the motivation for this study in the Asir region of Saudi Arabia. It was confirmed that merging has a strong effect on storm development in this region. The data analysis shows that an increase in the median of the distribution of maximum reflectivity was observed just after merging and was equal to 3.9 dBZ. A detailed analysis of the individual merge cases compared the merged storm Pflux and mass to the sum of the individual Feeder and Storm portions just before merging for each case. The merged storm Pflux increased an average of 106% over the 20-min period after merging, and the mass increased on average 143%. The merged storm clearly became larger and more severe than the sum of the two parts prior to merging. One consequence of this study is that any attempts to evaluate the precipitation enhancement effects of cloud seeding must also include the issue of cloud mergers because merging can have a significant effect on the results.

Charge-pickup of 238U at relativistic energies

International Nuclear Information System (INIS)

Rubehn, T.; Bassini, R.; Blaich, T.; Imme, G.; Iori, I.; Kunze, W.D.; Lindenstruth, V.; Lynen, U.; Moehlenkamp, T.; Moretto, L.G.; Ocker, B.; Pochodzalla, J.; Raciti, G.; Schuettauf, A.; Serfling, V.; Trautmann, W.; Trzcinski, A.; Verde, G.; Woerner, A.; Zude, E.; Zwieglinski, B.

1995-10-01

Cross sections for the charge-pickup of 238 U projectiles were measured at E/A=600 and 1000 MeV for seven different targets (Be, C, Al, Cu, In, Au and U). Events with two fission fragments with a sum charge of 93 in the exit channel were selected. Due to the significant excitation energy, the dominant part of produced Np nuclei fission instead of decaying to the ground state by evaporation. The observed cross sections can be well reproduced by intranuclear-cascade-plus-evaporation calculations and, therefore, confirm recent results that no exotic processes are needed to explain charge-pickup processes. (orig.)

Charge-transfer properties in the gas electron multiplier

International Nuclear Information System (INIS)

Han, Sanghyo; Kim, Yongkyun; Cho, Hyosung

2004-01-01

The charge transfer properties of a gas electron multiplier (GEM) were systematically investigated over a broad range of electric field configurations. The electron collection efficiency and the charge sharing were found to depend on the external fields, as well as on the GEM voltage. The electron collection efficiency increased with the collection field up to 90%, but was essentially independent of the drift field strength. A double conical GEM has a 10% gain increase with time due to surface charging by avalanche ions whereas this effect was eliminated with the cylindrical GEM. The positive-ion feedback is also estimated. (author)

42 CFR 60.15 - Other charges to the borrower.

Science.gov (United States)

2010-10-01

... fails to pay all of a required installment payment or fails to provide written evidence that verifies eligibility for the deferment of the payment within 30 days after the payment's due date, the lender or holder will require that the borrower pay a late charge. A late charge must be equal to 5 percent of the...

Simulation study of charged nanoparticles confined in a rectangular tube with discrete wall charges.

Science.gov (United States)

Yuet, Pak K

2006-03-28

The development of novel nanomaterials has been a subject of intense interest in recent years. An interesting structure among these materials is the so-called "pea pods" (i.e., nanoparticles confined in nanotubes). To facilitate the development and commercialization of these materials, it is important that we have an in-depth understanding of their behavior. The study of confined charged particles is particularly challenging because of the long-ranged nature of electrostatic interaction, and both interparticle and particle-confinement interactions are likely to play a role in determining the system behavior. The primary objective of this study is to develop a better understanding of the behavior of charged nanoparticles in a charged tubular confinement using Monte Carlo simulation, with particular focus on the effect of electrostatic interactions on the structure of the particles. Simulation results have shown that (i) the structuring of confined particles is associated with the asymmetry of the long-ranged interaction and (ii) factors such as confinement geometry and particle charge and size asymmetry can be manipulated to produce different particle structures. The present study represents the first step in an attempt to gain further insight into the behavior of confined nanosystems, with the ultimate objective of exploiting these characteristics, particularly the interactions between the confined particles and their external environment, in developing novel nanomaterials.

Portico charging to control column gradient in the ESTU

International Nuclear Information System (INIS)

McKay, J.W.

1989-01-01

The problem of gradient control in the ESTU is made more complicated than in a standard machine by the presence of a Portico. Normally charge is supplied to the terminal of a Van De Graaff by chains or a belt, then flows away from the terminal via resistor chains or directly to the corona point. In addition, charge may be drawn from the terminal due to the action of radiation sources. This paper reports on efforts to charge the Portico to control column gradient

Moment-Preserving Computational Approach for High Energy Charged Particle Transport

Science.gov (United States)

2016-05-16

posed, but with modified cross sections such that the resulting single-event Monte Carlo simulation is computationally efficient (minutes vs . days...configurations, which are all characteristics of real world applications. In other words , it is possible to simulate real, physical phenomena using charged...0 < 0.95) ~ 1 2() ≫ 1, (3) Demonstrating that scattering is highly forward peaked. Thus, the picture of charged particle interactions

Thermal noise due to surface-charge effects within the Debye layer of endogenous structures in dendrites.

Science.gov (United States)

Poznanski, Roman R

2010-02-01

An assumption commonly used in cable theory is revised by taking into account electrical amplification due to intracellular capacitive effects in passive dendritic cables. A generalized cable equation for a cylindrical volume representation of a dendritic segment is derived from Maxwell's equations under assumptions: (i) the electric-field polarization is restricted longitudinally along the cable length; (ii) extracellular isopotentiality; (iii) quasielectrostatic conditions; and (iv) homogeneous medium with constant conductivity and permittivity. The generalized cable equation is identical to Barenblatt's equation arising in the theory of infiltration in fissured strata with a known analytical solution expressed in terms of a definite integral involving a modified Bessel function and the solution to a linear one-dimensional classical cable equation. Its solution is used to determine the impact of thermal noise on voltage attenuation with distance at any particular time. A regular perturbation expansion for the membrane potential about the linear one-dimensional classical cable equation solution is derived in terms of a Green's function in order to describe the dynamics of free charge within the Debye layer of endogenous structures in passive dendritic cables. The asymptotic value of the first perturbative term is explicitly evaluated for small values of time to predict how the slowly fluctuating (in submillisecond range) electric field attributed to intracellular capacitive effects alters the amplitude of the membrane potential. It was found that capacitive effects are almost negligible for cables with electrotonic lengths L>0.5 , contributes up to 10% of the signal for cables with electrotonic lengths in the range between 0.25due to

Temperature dependent charge transport in poly(3-hexylthiophene) diodes

Science.gov (United States)

Rahaman, Abdulla Bin; Sarkar, Atri; Banerjee, Debamalya

2018-04-01

In this work, we present charge transport properties of poly(3-hexylthiophene) (P3HT) diodes under dark conditions. Temperature dependent current-voltage (J-V) characteristics shows that charge transport represents a transition from ohomic to trap limited current. The forward current density obeys a power law J˜Vm, m>2 represents the space charge limited current region in presence of traps within the band gap. Frequency dependent conductivity has been studied in a temperature range 150K-473K. The dc conductivity values show Arrhenius like behavior and it gives conductivity activation energy 223 meV. Temperature dependent conductivity indicates a thermodynamic transition of our system.

Interaction of singly and multiply charged ions with a lithium-fluoride surface

International Nuclear Information System (INIS)

Wirtz, L.

2001-10-01

Charge transfer between slow ions and an ionic crystal surface still poses a considerable challenge to theory due to the intrinsic many-body character of the system. For the neutralization of multiply charged ions in front of metal surfaces, the Classical Over the Barrier (COB) model is a widely used tool. We present an extension of this model to ionic crystal surfaces where the localization of valence electrons at the anion sites and the lack of cylindrical symmetry of the ion-surface system impede a simple analytical estimate of electron transfer rates. We use a classical trajectory Monte Carlo approach to calculate electron transfer rates for different charge states of the projectile ion. With these rates we perform a Monte Carlo simulation of the neutralization of slow Ne10+ ions in vertical incidence on an LiF surface. Capture of one or several electrons may lead to a local positive charge up of the surface. The projectile dynamics depends on the balance between the repulsion due to this charge and the attraction due to the self-image potential. In a simulation that treats electronic and nuclear dynamics simultaneously, we show that the image attraction dominates over the repulsive force. Backscattering of very slow multiply charged projectiles high above the surface without touching it ('trampoline effect') does not take place. Instead, the projectile ion penetrates into the surface or is reflected due to close binary collision with surface ions. The case of a singly charged ion in front of an LiF surface is within the reach of ab-initio calculations. We use a multi-configuration self consistent field (MCSCF) and a multi-reference configuration interaction (MR-CI) method to calculate adiabatic potential energy curves for a system consisting of the projectile ion and an embedded cluster of surface ions. With increasing cluster size, the energy levels of the embedded cluster converge towards the band structure of the infinitely extended solid. Due to

Dual structure in the charge excitation spectrum of electron-doped cuprates

Science.gov (United States)

Bejas, Matías; Yamase, Hiroyuki; Greco, Andrés

2017-12-01

Motivated by the recent resonant x-ray scattering (RXS) and resonant inelastic x-ray scattering (RIXS) experiments for electron-doped cuprates, we study the charge excitation spectrum in a layered t -J model with the long-range Coulomb interaction. We show that the spectrum is not dominated by a specific type of charge excitations, but by different kinds of charge fluctuations, and is characterized by a dual structure in the energy space. Low-energy charge excitations correspond to various types of bond-charge fluctuations driven by the exchange term (J term), whereas high-energy charge excitations are due to usual on-site charge fluctuations and correspond to plasmon excitations above the particle-hole continuum. The interlayer coupling, which is frequently neglected in many theoretical studies, is particularly important to the high-energy charge excitations.

Fast charge implications: Pack and cell analysis and comparison

Science.gov (United States)

Tanim, Tanvir R.; Shirk, Matthew G.; Bewley, Randy L.; Dufek, Eric J.; Liaw, Bor Yann

2018-03-01

This study investigates the effect of 50-kW (about 2C) direct current fast charging on a full-size battery electric vehicle's battery pack in comparison to a pack exclusively charged at 3.3 kW, which is the common alternating current Level 2 charging power level. Comparable scaled charging protocols are also independently applied to individual cells at three different temperatures, 20 °C, 30 °C, and 40 °C, to perform a comparative analysis with the packs. Dominant cell-level aging modes were identified through incremental capacity analysis and compared with full packs to gain a clear understanding of additional key factors that affect pack aging. While the cell-level study showed a minor impact on performance due to direct current fast charging, the packs showed a significantly higher rate of capacity fade under similar charging protocols. This indicates that pack-level aging cannot be directly extrapolated from cell evaluation. Delayed fast charging, completing shortly before discharge, was found to have less of an impact on battery degradation than conventional alternating current Level 2 charging.

On the nature of high field charge transport in reinforced silicone dielectrics: Experiment and simulation

Energy Technology Data Exchange (ETDEWEB)

Huang, Yanhui, E-mail: huangy12@rpi.edu; Schadler, Linda S. [Department of Material Science and Engineering, Rensselaer Polytechnic Institute, 110 8th street, Troy, New York 12180 (United States)

2016-08-07

The high field charge injection and transport properties in reinforced silicone dielectrics were investigated by measuring the time-dependent space charge distribution and the current under dc conditions up to the breakdown field and were compared with the properties of other dielectric polymers. It is argued that the energy and spatial distribution of localized electronic states are crucial in determining these properties for polymer dielectrics. Tunneling to localized states likely dominates the charge injection process. A transient transport regime arises due to the relaxation of charge carriers into deep traps at the energy band tails and is successfully verified by a Monte Carlo simulation using the multiple-hopping model. The charge carrier mobility is found to be highly heterogeneous due to the non-uniform trapping. The slow moving electron packet exhibits a negative field dependent drift velocity possibly due to the spatial disorder of traps.

Space-charge Effect on Electroresistance in Metal-Ferroelectric-Metal capacitors

Science.gov (United States)

Tian, Bo Bo; Liu, Yang; Chen, Liu Fang; Wang, Jian Lu; Sun, Shuo; Shen, Hong; Sun, Jing Lan; Yuan, Guo Liang; Fusil, Stéphane; Garcia, Vincent; Dkhil, Brahim; Meng, Xiang Jian; Chu, Jun Hao

2015-12-01

Resistive switching through electroresistance (ER) effect in metal-ferroelectric-metal (MFM) capacitors has attracted increasing interest due to its potential applications as memories and logic devices. However, the detailed electronic mechanisms resulting in large ER when polarisation switching occurs in the ferroelectric barrier are still not well understood. Here, ER effect up to 1000% at room temperature is demonstrated in C-MOS compatible MFM nanocapacitors with a 8.8 nm-thick poly(vinylidene fluoride) (PVDF) homopolymer ferroelectric, which is very promising for silicon industry integration. Most remarkably, using theory developed for metal-semiconductor rectifying contacts, we derive an analytical expression for the variation of interfacial barrier heights due to space-charge effect that can interpret the observed ER response. We extend this space-charge model, related to the release of trapped charges by defects, to MFM structures made of ferroelectric oxides. This space-charge model provides a simple and straightforward tool to understand recent unusual reports. Finally, this work suggests that defect-engineering could be an original and efficient route for tuning the space-charge effect and thus the ER performances in future electronic devices.

Charging of Dust Grains in a Nuclear-Induced Plasma at High Pressures

International Nuclear Information System (INIS)

Pal’, A. F.; Starostin, A. N.; Filippov, A. V.

2001-01-01

The process of dust-grain charging in plasmas produced by radioactive decay products or spontaneous fission fragments in air and xenon at high pressures is studied numerically in the hydrodynamic approximation. It is shown that, at sufficiently high rates of gas ionization, the dust grains in air are charged by electrons rather than ions, so that the grain charge in air is comparable to that in electropositive gases. The results of numerical calculations based on a complete model agree well with the experimental data. The time evolution of the grain charge is investigated, and the characteristic time scales on which the grains acquire an electric charge are established. The validity of approximate theories of dust-grain charging in electropositive and electronegative gases at high pressures is examined

Drift of the center of motion for a charged particle due to radiation effects

Energy Technology Data Exchange (ETDEWEB)

Ares De Parga, G.; Mares, R. [Instituto Politecnico Nacional, Zacatenco (Mexico). Dept. de Fisica, Escuela de Fisica y Matematica

1999-10-01

Through parametrization of the relativistic Larmor formula, one can find the trajectory of a charged particle in a uniform magnetic field. Simultaneously, there exists a drift of the center of curvature for the same. This effect is quantitatively compared with the predictions by other equations of motion, such as Dirac, Mo-Papas, Herrera, Bonnor and Cardirola and the one recently obtained by Hartemann and others. The paper proposes an experiment to verify the predicted effect, both qualitative and quantitative.

Drift of the center of motion for a charged particle due to radiation effects

International Nuclear Information System (INIS)

Ares De Parga, G.; Mares, R.

1999-01-01

Through parametrization of the relativistic Larmor formula, one can find the trajectory of a charged particle in a uniform magnetic field. Simultaneously, there exists a drift of the center of curvature for the same. This effect is quantitatively compared with the predictions by other equations of motion, such as Dirac, Mo-Papas, Herrera, Bonnor and Cardirola and the one recently obtained by Hartemann and others. The paper proposes an experiment to verify the predicted effect, both qualitative and quantitative

MOHOS-type memory performance using HfO2 nanoparticles as charge trapping layer and low temperature annealing

International Nuclear Information System (INIS)

Molina, Joel; Ortega, Rafael; Calleja, Wilfrido; Rosales, Pedro; Zuniga, Carlos; Torres, Alfonso

2012-01-01

Highlights: ► HfO 2 nanoparticles used as charge trapping layer in MOHOS memory devices. ► Increasing HfO 2 nanoparticles concentration enhances charge injection and trapping. ► Enhancement of memory performance with low temperature annealing. ► Charge injection is done without using any hot-carrier injection mechanism. ► Using injected charge density is better for comparison of scaled memory devices. - Abstract: In this work, HfO 2 nanoparticles (np-HfO 2 ) are embedded within a spin-on glass (SOG)-based oxide matrix and used as a charge trapping layer in metal–oxide–high-k–oxide–silicon (MOHOS)-type memory applications. This charge trapping layer is obtained by a simple sol–gel spin coating method after using different concentrations of np-HfO 2 and low temperature annealing (down to 425 °C) in order to obtain charge–retention characteristics with a lower thermal budget. The memory's charge trapping characteristics are quantized by measuring both the flat-band voltage shift of MOHOS capacitors (writing/erasing operations) and their programming retention times after charge injection while correlating all these data to np-HfO 2 concentration and annealing temperature. Since a large memory window has been obtained for our MOHOS memory, the relatively easy injection/annihilation (writing/erasing) of charge injected through the substrate opens the possibility to use this material as an effective charge trapping layer. It is shown that by using lower annealing temperatures for the charge trapping layer, higher densities of injected charge are obtained along with enhanced retention times. In conclusion, by using np-HfO 2 as charge trapping layer in memory devices, moderate programming and retention characteristics have been obtained by this simple and yet low-cost spin-coating method.

Charge orders in organic charge-transfer salts

International Nuclear Information System (INIS)

Kaneko, Ryui; Valentí, Roser; Tocchio, Luca F; Becca, Federico

2017-01-01

Motivated by recent experimental suggestions of charge-order-driven ferroelectricity in organic charge-transfer salts, such as κ -(BEDT-TTF) 2 Cu[N(CN) 2 ]Cl, we investigate magnetic and charge-ordered phases that emerge in an extended two-orbital Hubbard model on the anisotropic triangular lattice at 3/4 filling. This model takes into account the presence of two organic BEDT-TTF molecules, which form a dimer on each site of the lattice, and includes short-range intramolecular and intermolecular interactions and hoppings. By using variational wave functions and quantum Monte Carlo techniques, we find two polar states with charge disproportionation inside the dimer, hinting to ferroelectricity. These charge-ordered insulating phases are stabilized in the strongly correlated limit and their actual charge pattern is determined by the relative strength of intradimer to interdimer couplings. Our results suggest that ferroelectricity is not driven by magnetism, since these polar phases can be stabilized also without antiferromagnetic order and provide a possible microscopic explanation of the experimental observations. In addition, a conventional dimer-Mott state (with uniform density and antiferromagnetic order) and a nonpolar charge-ordered state (with charge-rich and charge-poor dimers forming a checkerboard pattern) can be stabilized in the strong-coupling regime. Finally, when electron–electron interactions are weak, metallic states appear, with either uniform charge distribution or a peculiar 12-site periodicity that generates honeycomb-like charge order. (paper)

Control Strategy for Vehicle Inductive Wireless Charging Based on Load Adaptive and Frequency Adjustment

Directory of Open Access Journals (Sweden)

Shichun Yang

2018-05-01

Full Text Available Wireless charging system for electric vehicles is a hot research issue in the world today. Since the existing research on wireless charging is mostly forward-looking aimed at low-power appliances like household appliances, while electric vehicles need a high-power, high-efficiency, and strong coupling wireless charging system. In this paper, we have specifically designed a 6.6 KW wireless charging system for electric vehicles and have proposed a control strategy suitable for electric vehicles according to its power charging characteristics and existing common wired charging protocol. Firstly, the influence of the equivalent load and frequency bifurcation on a wireless charging system is analyzed in this paper. Secondly, an adaptive load control strategy matching the characteristics of the battery, and the charging pile is put forward to meet the constant current and constant voltage charging requirements to improve the system efficiency. In addition, the frequency adjustment control strategy is designed to realize the real-time dynamic optimization of the entire system. It utilizes the improved methods of rapid judgment, variable step length matching and frequency splitting recognition, which are not adopted in early related researches. Finally, the results of 6.6 kW test show that the control strategy works perfectly since system response time can be reduced to less than 1 s, and the overall efficiency of the wireless charging system and the grid power supply module can reach up to 91%.

Charge transfer devices and their application in physics

Energy Technology Data Exchange (ETDEWEB)

Soroko, L M [Joint Inst. for Nuclear Research, Dubna (USSR)

1979-01-01

Physical properties and technical specifications of charge transfer devices (CTD) are reviewed. The CTD are semiconductor devices based on silicon single crystals. The limiting charge density of the CTD, their efficiency of charge transfer, the background noise and radiation effects are considered. Fast response and low energy consumption are characteristic features of the devices. The application of the CTD in storage devices, real time spectral data processing systems and in streamer chambers is described. The algorithms of topological transformations in the stage of scanning particle track images, which can be realized with the help of the CTD are shortly considered. It is pointed out that applications of the CTD in different fields of science and technology are numerous and expanding.

Understanding charge transport in molecular electronics.

Science.gov (United States)

Kushmerick, J J; Pollack, S K; Yang, J C; Naciri, J; Holt, D B; Ratner, M A; Shashidhar, R

2003-12-01

For molecular electronics to become a viable technology the factors that control charge transport across a metal-molecule-metal junction need to be elucidated. We use an experimentally simple crossed-wire tunnel junction to interrogate how factors such as metal-molecule coupling, molecular structure, and the choice of metal electrode influence the current-voltage characteristics of a molecular junction.

Field observations of the electrostatic charges of blowing snow in Hokkaido, Japan

Science.gov (United States)

Omiya, S.; Sato, A.

2011-12-01

An electrostatic charge of blowing snow may be a contributing factor in the formation of a snow drift and a snow cornice, and changing of the trajectory of own motion. However, detailed electrification characteristics of blowing snow are not known as there are few reports of charge measurements. We carried out field observations of the electrostatic charges of blowing snow in Tobetsu, Hokkaido, Japan in the mid winter of 2011. An anemovane and a thermohygrometer were used for the meteorological observation. Charge-to-mass ratios of blowing snow were obtained by a Faraday-cage, an electrometer and an electric balance. In this observation period, the air temperature during the blowing snow event was -6.5 to -0.5 degree Celsius. The measured charges in this observation were consistent with the previous studies in sign, which is negative, but they were smaller than the previous one. In most cases, the measured values increased with the temperature decrease, which corresponds with previous studies. However, some results contradicted the tendency, and the maximum value was obtained on the day of the highest air temperature of -0.5 degree Celsius. This discrepancy may be explained from the difference of the snow surface condition on observation day. The day when the maximum value was obtained, the snow surface was covered with old snow, and hard. On the other hand, in many other cases, the snow surface was covered with the fresh snow, and soft. Blowing snow particles on the hard surface can travel longer distance than on the soft one. Therefore, it can be surmised that the hard surface makes the blowing snow particles accumulate a lot of negative charges due to a large number of collisions to the surface. This can be supported by the results of the wind tunnel experiments by Omiya and Sato (2011). By this field observation, it was newly suggested that the electrostatic charge of blowing snow are influenced greatly by the difference of the snow surface condition. REFERENCE

A relativistic self-consistent model for studying enhancement of space charge limited field emission due to counter-streaming ions

International Nuclear Information System (INIS)

Lin, M. C.; Lu, P. S.; Chang, P. C.; Ragan-Kelley, B.; Verboncoeur, J. P.

2014-01-01

Recently, field emission has attracted increasing attention despite the practical limitation that field emitters operate below the Child-Langmuir space charge limit. By introducing counter-streaming ion flow to neutralize the electron charge density, the space charge limited field emission (SCLFE) current can be dramatically enhanced. In this work, we have developed a relativistic self-consistent model for studying the enhancement of SCLFE by a counter-streaming ion current. The maximum enhancement is found when the ion effect is saturated, as shown analytically. The solutions in non-relativistic, intermediate, and ultra-relativistic regimes are obtained and verified with 1-D particle-in-cell simulations. This self-consistent model is general and can also serve as a benchmark or comparison for verification of simulation codes, as well as extension to higher dimensions

q-deformed charged fermion coherent states and SU(3) charged, Hyper-charged fermion coherent states

International Nuclear Information System (INIS)

Hao Sanru; Li Guanghua; Long Junyan

1994-01-01

By virtue of the algebra of the q-deformed fermion oscillators, the q-deformed charged fermion coherent states and SU(3) charged, hyper-charged fermion coherent states are discussed. The explicit forms of the two kinds of coherent states mentioned above are obtained by making use of the completeness of base vectors in the q-fermion Fock space. By comparing the q-deformed results with the ordinary results, it is found that the q-deformed charged fermion coherent states and SU(3) charged, hyper-charged fermion coherent states are automatically reduced to the ordinary charged fermion coherent states and SU(3) charged hyper-charged fermion coherent states if the deformed parameter q→1

Investigation of a new type charging belt

International Nuclear Information System (INIS)

Jones, N.L.

1994-01-01

There are many desirable characteristics for an electrostatic accelerator charging belt. An attempt has been made to find a belt that improves on these properties over the stock belt. Results of the search, procurement, and 1,500 hours of operational experience with a substantially different belt are reported

A gateless charge integrator for Borexino energy measurement

International Nuclear Information System (INIS)

Lagomarsino, V.; Testera, G.

1999-01-01

A gateless charge integrator designed for the energy measurement in the Borexino experiment is described and the results of various tests performed on prototypes are shown. The circuit integrates always its input taking advantage of the AC coupling to the photomultipliers that equalizes to zero the charge associated with each event signal. A double sampling of the integrator output allows to perform a charge measurement in principle without dead time, avoiding the use of gate signals and baseline restoration networks and permitting a precise detection of the fast correlated events (delayed coincidences due to the decay of a nuclide producing a daughter having a lifetime in the tens of ns time range). The precision of the charge measurement is discussed together with the performances of the front end Borexino board where the integrator is mounted

Improved Interaction Potentials for Charged Residues in Proteins

DEFF Research Database (Denmark)

Kepp, Kasper Planeta

2008-01-01

Electrostatic interactions dominate the structure and free energy of biomolecules. To obtain accurate free energies involving charged groups from molecular simulations, OPLS-AA parameters have been reoptimized using Monte Carlo free energy perturbation. New parameters fit a self-consistent, exper......Electrostatic interactions dominate the structure and free energy of biomolecules. To obtain accurate free energies involving charged groups from molecular simulations, OPLS-AA parameters have been reoptimized using Monte Carlo free energy perturbation. New parameters fit a self......, TIP4P or TIP3P; i.e., each water model requires specific water-charged molecule interaction potentials. New models (models 1 and 3) are thus described for both water models. Uncertainties in relative free energies of charged residues are ~2 kcal/mol with the new parameters, due to variations in system...

Operating modes of high-Tc composite superconductors and thermal runaway conditions under current charging

International Nuclear Information System (INIS)

Romanovskii, V R; Watanabe, K

2006-01-01

The operating thermal and electric modes of a high-T c superconducting composite in partially and fully penetrated states induced by the charging current are investigated. They were studied under conditions in which the current charging rate, the volume fraction of the superconductor in a composite or the temperature of the cooling bath were changed. The transient behaviour of the voltage-current dependence, which is characteristic during stable and unstable increases in electric field inside the composite under a continuous current charging, is discussed. Simulations were done using zero- and one-dimensional steady and unsteady thermoelectric models with a power equation describing the virgin voltage-current characteristic of a superconductor. It is found that some thermoelectric trends underlie the shape of the voltage-current characteristic of the high-T c superconducting composite. These have to be considered during experiments in which the critical or quench currents are defined. First, in the initial stage of the fully penetrated regime (in the low voltage range), the electric field distribution does not have a uniform character. These states depend on the volume fraction of the superconductor and the current charging rate: the higher these quantities, the higher the heterogeneity of the electric field. Second, during the stable over-critical regime (in the high voltage range) occurring in complete penetration modes, the evolution of the electric field may depend on the relevant temperature increase of a composite according to the corresponding increase in its temperature-dependent heat capacity. Consequently, the shape of the voltage-current characteristic of a composite high-T c superconductor during continuous current charging, both before and after thermal runaway, has only a positive slope. Moreover, it is proved that the growth of the fully penetrated part of the voltage-current characteristic becomes less intensive when the current charging rate or the

Simulation of distributed parameter system consisting of charged and neutral particles

International Nuclear Information System (INIS)

Grover, P.S.; Sinha, K.V.

1986-01-01

The time-dependent behavior of positively charged light particles have been simulated in an assembly of heavy gas atoms. The system is formulated in terms of partial differential equation. The stability and convergence of the numerical algorithm has been examined. Using this formulation effects of external electric field and temperature have been investigated on the lifetime and distribution function characteristics of charged particles

Magnetically coupled resonance wireless charging technology principles and transfer mechanisms

Science.gov (United States)

Zhou, Jiehua; Wan, Jian; Ma, Yinping

2017-05-01

With the tenure of Electric-Vehicle rising around the world, the charging methods have been paid more and more attention, the current charging mode mainly has the charging posts and battery swapping station. The construction of the charging pile or battery swapping station not only require lots of manpower, material costs but the bare conductor is also easy to generate electric spark hidden safety problems, still occupies large space. Compared with the wired charging, wireless charging mode is flexible, unlimited space and location factors and charging for vehicle safety and quickly. It complements the traditional charging methods in adaptability and the independent charge deficiencies. So the researching the wireless charging system have an important practical significance and application value. In this paper, wireless charging system designed is divided into three parts: the primary side, secondary side and resonant coupling. The main function of the primary side is to generate high-frequency alternating current, so selecting CLASS-E amplifier inverter structure through the research on full bridge, half-bridge and power amplification circuit. Addition, the wireless charging system is susceptible to outside interference, frequency drift phenomenon. Combined with the wireless energy transmission characteristics, resonant parts adopt resonant coupling energy transmission scheme and the Series-Series coupling compensation structure. For the electric vehicle charging power and voltage requirements, the main circuit is a full bridge inverter and Boost circuit used as the secondary side.

MOHOS-type memory performance using HfO{sub 2} nanoparticles as charge trapping layer and low temperature annealing

Energy Technology Data Exchange (ETDEWEB)

Molina, Joel, E-mail: jmolina@inaoep.mx [National Institute of Astrophysics, Optics and Electronics. Electronics Department, Luis Enrique Erro 1, Tonantzintla, Puebla 72000 (Mexico); Ortega, Rafael; Calleja, Wilfrido; Rosales, Pedro; Zuniga, Carlos; Torres, Alfonso [National Institute of Astrophysics, Optics and Electronics. Electronics Department, Luis Enrique Erro 1, Tonantzintla, Puebla 72000 (Mexico)

2012-09-20

Highlights: Black-Right-Pointing-Pointer HfO{sub 2} nanoparticles used as charge trapping layer in MOHOS memory devices. Black-Right-Pointing-Pointer Increasing HfO{sub 2} nanoparticles concentration enhances charge injection and trapping. Black-Right-Pointing-Pointer Enhancement of memory performance with low temperature annealing. Black-Right-Pointing-Pointer Charge injection is done without using any hot-carrier injection mechanism. Black-Right-Pointing-Pointer Using injected charge density is better for comparison of scaled memory devices. - Abstract: In this work, HfO{sub 2} nanoparticles (np-HfO{sub 2}) are embedded within a spin-on glass (SOG)-based oxide matrix and used as a charge trapping layer in metal-oxide-high-k-oxide-silicon (MOHOS)-type memory applications. This charge trapping layer is obtained by a simple sol-gel spin coating method after using different concentrations of np-HfO{sub 2} and low temperature annealing (down to 425 Degree-Sign C) in order to obtain charge-retention characteristics with a lower thermal budget. The memory's charge trapping characteristics are quantized by measuring both the flat-band voltage shift of MOHOS capacitors (writing/erasing operations) and their programming retention times after charge injection while correlating all these data to np-HfO{sub 2} concentration and annealing temperature. Since a large memory window has been obtained for our MOHOS memory, the relatively easy injection/annihilation (writing/erasing) of charge injected through the substrate opens the possibility to use this material as an effective charge trapping layer. It is shown that by using lower annealing temperatures for the charge trapping layer, higher densities of injected charge are obtained along with enhanced retention times. In conclusion, by using np-HfO{sub 2} as charge trapping layer in memory devices, moderate programming and retention characteristics have been obtained by this simple and yet low-cost spin-coating method.

The charged bubble oscillator: Dynamics and thresholds

Indian Academy of Sciences (India)

The nonlinear, forced oscillations of a bubble in a fluid due to an external pressure field are studied theoretically. ... for the system, delineating different dynamics. Keywords. ..... (c) Power spectral density of the charged and uncharged bub-.

Langevin dynamics of conformational transformations induced by the charge-curvature interaction

DEFF Research Database (Denmark)

Gaididei, Yuri Borisovich; Gorria, C.; Christiansen, Peter Leth

2009-01-01

The role of thermal fluctuations in the conformational dynamics of a single closed filament is studied. It is shown that, due to the interaction between charges and bending degrees of freedom, initially circular chains may undergo transformation to polygonal shape.......The role of thermal fluctuations in the conformational dynamics of a single closed filament is studied. It is shown that, due to the interaction between charges and bending degrees of freedom, initially circular chains may undergo transformation to polygonal shape....

Global geometry of two-dimensional charged black holes

International Nuclear Information System (INIS)

Frolov, Andrei V.; Kristjansson, Kristjan R.; Thorlacius, Larus

2006-01-01

The semiclassical geometry of charged black holes is studied in the context of a two-dimensional dilaton gravity model where effects due to pair-creation of charged particles can be included in a systematic way. The classical mass-inflation instability of the Cauchy horizon is amplified and we find that gravitational collapse of charged matter results in a spacelike singularity that precludes any extension of the spacetime geometry. At the classical level, a static solution describing an eternal black hole has timelike singularities and multiple asymptotic regions. The corresponding semiclassical solution, on the other hand, has a spacelike singularity and a Penrose diagram like that of an electrically neutral black hole. Extremal black holes are destabilized by pair-creation of charged particles. There is a maximally charged solution for a given black hole mass but the corresponding geometry is not extremal. Our numerical data exhibits critical behavior at the threshold for black hole formation

Normal Reflection Characteristics of One-Dimensional Unsteady Flow Shock Waves on Rigid Walls from Pulse Discharge in Water

Directory of Open Access Journals (Sweden)

Dong Yan

2017-01-01

Full Text Available Strong shock waves can be generated by pulse discharge in water, and the characteristics due to the shock wave normal reflection from rigid walls have important significance to many fields, such as industrial production and defense construction. This paper investigates the effects of hydrostatic pressures and perturbation of wave source (i.e., charging voltage on normal reflection of one-dimensional unsteady flow shock waves. Basic properties of the incidence and reflection waves were analyzed theoretically and experimentally to identify the reflection mechanisms and hence the influencing factors and characteristics. The results indicated that increased perturbation (i.e., charging voltage leads to increased peak pressure and velocity of the reflected shock wave, whereas increased hydrostatic pressure obviously inhibited superposition of the reflection waves close to the rigid wall. The perturbation of wave source influence on the reflected wave was much lower than that on the incident wave, while the hydrostatic pressure obviously affected both incident and reflection waves. The reflection wave from the rigid wall in water exhibited the characteristics of a weak shock wave, and with increased hydrostatic pressure, these weak shock wave characteristics became more obvious.

The effect of space charge force on beams extracted from ECR ion sources

International Nuclear Information System (INIS)

Xie, Z.Q.

1989-01-01

A new 3 dimensional ray tracing code BEAM-3D, with a simple model to calculate the space charge force of multiple ion species, is under development and serves as a theoretical tool to study the ECRIS beam formation. Excellent agreement between the BEAM-3D calculations and beam profile and emittance measurements of the total extracted helium 1+ beam from the RTECR ion source was obtained when a low degree of beam neutralization was assumed in the calculations. The experimental evidence indicates that the positive space charge effects dominate the early RTECR ion source beam formation and beamline optics matching process. A review of important beam characteristics is made, including a conceptual model for the space charge beam blow up. Better beam transport through the RTECR beamline analysis magnet has resulted after an extraction geometry modification in which the space charge force was more correctly matched. This work involved the development of an online beam characteristic measuring apparatus which will also be described

Prospects for charge sensitive amplifiers in scaled CMOS

Science.gov (United States)

O'Connor, Paul; De Geronimo, Gianluigi

2002-03-01

Due to its low cost and flexibility for custom design, monolithic CMOS technology is being increasingly employed in charge preamplifiers across a broad range of applications, including both scientific research and commercial products. The associated detectors have capacitances ranging from a few tens of fF to several hundred pF. Applications call for pulse shaping from tens of ns to tens of μs, and constrain the available power per channel from tens of μW to tens of mW. At the same time a new technology generation, with changed device parameters, appears every 2 years or so. The optimum design of the front-end circuitry is examined taking into account submicron device characteristics, weak inversion operation, the reset system, and power supply scaling. Experimental results from recent prototypes will be presented. We will also discuss the evolution of preamplifier topologies and anticipated performance limits as CMOS technology scales down to the 0.1 μm/1.0 V generation in 2006.

Prospects for charge sensitive amplifiers in scaled CMOS

International Nuclear Information System (INIS)

O'Connor, Paul; De Geronimo, Gianluigi

2002-01-01

Due to its low cost and flexibility for custom design, monolithic CMOS technology is being increasingly employed in charge preamplifiers across a broad range of applications, including both scientific research and commercial products. The associated detectors have capacitances ranging from a few tens of fF to several hundred pF. Applications call for pulse shaping from tens of ns to tens of μs, and constrain the available power per channel from tens of μW to tens of mW. At the same time a new technology generation, with changed device parameters, appears every 2 years or so. The optimum design of the front-end circuitry is examined taking into account submicron device characteristics, weak inversion operation, the reset system, and power supply scaling. Experimental results from recent prototypes will be presented. We will also discuss the evolution of preamplifier topologies and anticipated performance limits as CMOS technology scales down to the 0.1 μm/1.0 V generation in 2006

On the physics of dispersive electron transport characteristics in SnO2 nanoparticle-based dye sensitized solar cells.

Science.gov (United States)

Ashok, Aditya; Vijayaraghavan, S N; Unni, Gautam E; Nair, Shantikumar V; Shanmugam, Mariyappan

2018-04-27

The present study elucidates dispersive electron transport mediated by surface states in tin oxide (SnO 2 ) nanoparticle-based dye sensitized solar cells (DSSCs). Transmission electron microscopic studies on SnO 2 show a distribution of ∼10 nm particles exhibiting (111) crystal planes with inter-planar spacing of 0.28 nm. The dispersive transport, experienced by photo-generated charge carriers in the bulk of SnO 2 , is observed to be imposed by trapping and de-trapping processes via SnO 2 surface states present close to the band edge. The DSSC exhibits 50% difference in performance observed between the forward (4%) and reverse (6%) scans due to the dispersive transport characteristics of the charge carriers in the bulk of the SnO 2 . The photo-generated charge carriers are captured and released by the SnO 2 surface states that are close to the conduction band-edge resulting in a very significant variation; this is confirmed by the hysteresis observed in the forward and reverse scan current-voltage measurements under AM1.5 illumination. The hysteresis behavior assures that the charge carriers are accumulated in the bulk of electron acceptor due to the trapping, and released by de-trapping mediated by surface states observed during the forward and reverse scan measurements.

On the physics of dispersive electron transport characteristics in SnO2 nanoparticle-based dye sensitized solar cells

Science.gov (United States)

Ashok, Aditya; Vijayaraghavan, S. N.; Unni, Gautam E.; Nair, Shantikumar V.; Shanmugam, Mariyappan

2018-04-01

The present study elucidates dispersive electron transport mediated by surface states in tin oxide (SnO2) nanoparticle-based dye sensitized solar cells (DSSCs). Transmission electron microscopic studies on SnO2 show a distribution of ˜10 nm particles exhibiting (111) crystal planes with inter-planar spacing of 0.28 nm. The dispersive transport, experienced by photo-generated charge carriers in the bulk of SnO2, is observed to be imposed by trapping and de-trapping processes via SnO2 surface states present close to the band edge. The DSSC exhibits 50% difference in performance observed between the forward (4%) and reverse (6%) scans due to the dispersive transport characteristics of the charge carriers in the bulk of the SnO2. The photo-generated charge carriers are captured and released by the SnO2 surface states that are close to the conduction band-edge resulting in a very significant variation; this is confirmed by the hysteresis observed in the forward and reverse scan current-voltage measurements under AM1.5 illumination. The hysteresis behavior assures that the charge carriers are accumulated in the bulk of electron acceptor due to the trapping, and released by de-trapping mediated by surface states observed during the forward and reverse scan measurements.

Design of constant current charging power supply for J-TEXT ohmic field capacitor banks

International Nuclear Information System (INIS)

Lv Shudong; Zhang Ming; Rao Bo; Yu Kexun; Yang Cheng

2014-01-01

The charging characteristic of the capacitor charging power supply was analyzed with practical series resonant topology. The method that setting two current taps and regulating PWM switching frequency was putted forward with close loop controlling algorithm to charge the multi-group capacitor banks with constant current. A capacitor charging power supply with the max output current 6.5 A and the max output voltage 2000 V is designed. Experimental results show that, this power supply can charge the four capacitor banks to any four different voltages in 1 minute with charging accuracy less than 1%, and meet the requirements of J-TEXT ohmic field power system. (authors)

Facial Nerve Paralysis due to a Pleomorphic Adenoma with the Imaging Characteristics of a Facial Nerve Schwannoma

OpenAIRE

Nader, Marc-Elie; Bell, Diana; Sturgis, Erich M.; Ginsberg, Lawrence E.; Gidley, Paul W.

2014-01-01

Background Facial nerve paralysis in a patient with a salivary gland mass usually denotes malignancy. However, facial paralysis can also be caused by benign salivary gland tumors. Methods We present a case of facial nerve paralysis due to a benign salivary gland tumor that had the imaging characteristics of an intraparotid facial nerve schwannoma. Results The patient presented to our clinic 4 years after the onset of facial nerve paralysis initially diagnosed as Bell palsy. Computed tomograph...

Prediction and Experimental Evidence for Thermodynamically Stable Charged Orbital Domain Walls

Energy Technology Data Exchange (ETDEWEB)

Li, Qing’an; Gray, K. E.; Wilkins, S. B.; Garcia Fernandez, M.; Rosenkranz, S.; Zheng, H.; Mitchell, J. F.

2014-08-01

The quest for miniaturization is prevalent in many fields of modern science and technology. The ultimate limit for conduction would be a one-dimensional (1D) chain of atoms and, for example, carbon nanotubes are a notable approximation to this ideal. Here we present strong evidence for an unexpected phenomenon—a sliding charge-density wave along pseudo-1D, atomically homogeneous orbital domain walls (ODWs) in insulating bilayer manganite crystals. At a threshold electric field, crystals exhibit abrupt transformations to higher conductance, while x-ray diffraction confirms that these are not due to heating or melting of charge order. The conductance data resemble those of well-known pseudo-1D sliding-charge-density waves, in particular the presence of a depinning voltage. The vital link is our theoretical insight that ODWs must be partially charged due to competition between orbital-induced strain and Coulomb repulsion. The ideas found here embody a new principle for creating ultra-nano conductive paths in other materials and devices.

The description of charge transfer in fast negative ions scattering on water covered Si(100) surfaces

Energy Technology Data Exchange (ETDEWEB)

Chen, Lin; Qiu, Shunli; Liu, Pinyang; Xiong, Feifei; Lu, Jianjie; Liu, Yuefeng; Li, Guopeng; Liu, Yiran; Ren, Fei; Xiao, Yunqing; Gao, Lei; Zhao, Qiushuang; Ding, Bin; Li, Yuan [School of Nuclear Science and Technology, Lanzhou University, 730000 (China); Key Laboratory of Special Function Materials and Structure Design, Ministry of Education, Lanzhou University, 730000 (China); Guo, Yanling, E-mail: guoyanling@lzu.edu.cn [School of Nuclear Science and Technology, Lanzhou University, 730000 (China); Key Laboratory of Special Function Materials and Structure Design, Ministry of Education, Lanzhou University, 730000 (China); Chen, Ximeng, E-mail: chenxm@lzu.edu.cn [School of Nuclear Science and Technology, Lanzhou University, 730000 (China); Key Laboratory of Special Function Materials and Structure Design, Ministry of Education, Lanzhou University, 730000 (China)

2016-11-30

Highlights: • We first observe that negative-ion fractions present no variation with the doping concentration, which is very different from the results of low energy Li neutralization from doped Si samples. • Our work shows that the affinity levels and collision time significantly counteract the band gap effect on negative ion formation. The work will improve our understanding on electron transfer on semiconductor surfaces associated with doping. • In addition, we build a complete theoretical framework to quantitatively calculate the negative-ion fractions. • Our work is related to charge transfer on semiconductor surfaces, which will be of interest to a broad audience due to the wide necessity of the knowledge of charge exchange on semiconductor surfaces in different fields. - Abstract: Doping has significantly affected the characteristics and performance of semiconductor electronic devices. In this work, we study the charge transfer processes for 8.5–22.5 keV C{sup −} and F{sup −} ions scattering on H{sub 2}O-terminated p-type Si(100) surfaces with two different doping concentrations. We find that doping has no influence on negative-ion formation for fast collisions in this relatively high energy range. Moreover, we build a model to calculate negative ion fractions including the contribution from positive ions. The calculations support the nonadiabatic feature of charge transfer.

Strategies for Charging Electric Vehicles in the Electricity Market

Directory of Open Access Journals (Sweden)

Nina Juul

2015-06-01

Full Text Available This paper analyses different charging strategies for a fleet of electric vehicles. Along with increasing the realism of the strategies, the opportunity for acting on the regulating market is also included. We test the value of a vehicle owner that can choose when and how to charge; by presenting a model of four alternative charging strategies. We think of them as increasing in sophistication from dumb via delayed to deterministic and stochastic model-based charging. We show that 29% of the total savings from ‘dumb’ are due to delayed charging and that substantial additional gains come charging optimally in response to predicted spot prices, and – in some settings – additional gains from using the up and down regulating prices. Particularly, strategies are chosen from uncontrolled charging through deterministic optimization, to modelling the charging and bidding problem with stochastic programming. We show that all vehicle owners will benefit from acting more intelligently on the energy market. Furthermore, the high value of the stochastic solution shows that, in case the regulating price differs from the expected, the solution to the deterministic problem becomes infeasible.

Transport charge of gallium arsenide films synthesized on polycrystalline silicon by ion ablation

International Nuclear Information System (INIS)

Kabyshev, A V; Konusov, F V; Remnev, G E; Pavlov, S K

2014-01-01

Electrophysical and photoelectric properties of thin GaAs films deposited on polysilicon by pulse ion ablation using high-power ion beams have been investigated. The predominant charge carriers transfer mechanism in films and the type of dark and photoconductivity have been established. A vacuum annealing effect (10 −2 Pa, 300-1000 K) on energetic and kinetic characteristics of dark and photoconductivity, the transfer mechanism and the type of charge carriers have been determined. The most probable causes of changes in the film electric and photoelectric characteristics have been discussed

Acceleration of the charged particles due to chaotic scattering in the combined black hole gravitational field and asymptotically uniform magnetic field

International Nuclear Information System (INIS)

Stuchlik, Zdenek; Kolos, Martin

2016-01-01

To test the role of large-scale magnetic fields in accretion processes, we study the dynamics of the charged test particles in the vicinity of a black hole immersed into an asymptotically uniform magnetic field. Using the Hamiltonian formalism of the charged particle dynamics, we examine chaotic scattering in the effective potential related to the black hole gravitational field combined with the uniform magnetic field. Energy interchange between the translational and oscillatory modes of the charged particle dynamics provides a mechanism for charged particle acceleration along the magnetic field lines. This energy transmutation is an attribute of the chaotic charged particle dynamics in the combined gravitational and magnetic fields only, the black hole rotation is not necessary for such charged particle acceleration. The chaotic scatter can cause a transition to the motion along the magnetic field lines with small radius of the Larmor motion or vanishing Larmor radius, when the speed of the particle translational motion is largest and it can be ultra-relativistic. We discuss the consequences of the model of ionization of test particles forming a neutral accretion disc, or heavy ions following off-equatorial circular orbits, and we explore the fate of heavy charged test particles after ionization where no kick of heavy ions is assumed and only the switch-on effect of the magnetic field is relevant. We demonstrate that acceleration and escape of the ionized particles can be efficient along the Kerr black hole symmetry axis parallel to the magnetic field lines. We show that a strong acceleration of the ionized particles to ultra-relativistic velocities is preferred in the direction close to the magnetic field lines. Therefore, the process of ionization of Keplerian discs around the Kerr black holes can serve as a model of relativistic jets. (orig.)

Acceleration of the charged particles due to chaotic scattering in the combined black hole gravitational field and asymptotically uniform magnetic field

Energy Technology Data Exchange (ETDEWEB)

Stuchlik, Zdenek; Kolos, Martin [Silesian University in Opava, Faculty of Philosophy and Science, Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Opava (Czech Republic)

2016-01-15

To test the role of large-scale magnetic fields in accretion processes, we study the dynamics of the charged test particles in the vicinity of a black hole immersed into an asymptotically uniform magnetic field. Using the Hamiltonian formalism of the charged particle dynamics, we examine chaotic scattering in the effective potential related to the black hole gravitational field combined with the uniform magnetic field. Energy interchange between the translational and oscillatory modes of the charged particle dynamics provides a mechanism for charged particle acceleration along the magnetic field lines. This energy transmutation is an attribute of the chaotic charged particle dynamics in the combined gravitational and magnetic fields only, the black hole rotation is not necessary for such charged particle acceleration. The chaotic scatter can cause a transition to the motion along the magnetic field lines with small radius of the Larmor motion or vanishing Larmor radius, when the speed of the particle translational motion is largest and it can be ultra-relativistic. We discuss the consequences of the model of ionization of test particles forming a neutral accretion disc, or heavy ions following off-equatorial circular orbits, and we explore the fate of heavy charged test particles after ionization where no kick of heavy ions is assumed and only the switch-on effect of the magnetic field is relevant. We demonstrate that acceleration and escape of the ionized particles can be efficient along the Kerr black hole symmetry axis parallel to the magnetic field lines. We show that a strong acceleration of the ionized particles to ultra-relativistic velocities is preferred in the direction close to the magnetic field lines. Therefore, the process of ionization of Keplerian discs around the Kerr black holes can serve as a model of relativistic jets. (orig.)

Nonlinear periodic waves in dusty plasma with variable dust charge

International Nuclear Information System (INIS)

Yadav, Lakhan Lal; Bharuthram, R.

2002-01-01

Using the reductive perturbation method, we present a theory of nonlinear periodic waves, viz. the cnoidal waves, in a dusty plasma consisting of electrons, ions, and cold dust grains with charge fluctuations, which in the limiting case reduce to dust acoustic solitons. It is found that the frequency of the dust acoustic cnoidal wave increases with its amplitude. The dust charge fluctuations are found to affect the characteristics of the cnoidal waves

Spin Drag and Spin-Charge Separation in Cold Fermi Gases

International Nuclear Information System (INIS)

Polini, Marco; Vignale, Giovanni

2007-01-01

Low-energy spin and charge excitations of one-dimensional interacting fermions are completely decoupled and propagate with different velocities. These modes, however, can decay due to several possible mechanisms. In this Letter we expose a new facet of spin-charge separation: not only the speeds but also the damping rates of spin and charge excitations are different. While the propagation of long-wavelength charge excitations is essentially ballistic, spin propagation is intrinsically damped and diffusive. We suggest that cold Fermi gases trapped inside a tight atomic waveguide offer the opportunity to measure the spin-drag relaxation rate that controls the broadening of a spin packet

Enhancement of charge-transport characteristics in polymeric films using polymer brushes

DEFF Research Database (Denmark)

Whiting, G.L.; Snaith, H.J.; Khodabakhsh, S.

2006-01-01

We show that charge-transporting polymer chains in the brush conformation can be synthesized from a variety of substrates of interest, displaying a high degree of stretching and showing up to a 3 orders of magnitude increase in current density normal to the substrate as compared with a spin......-coated film. These nanostructured polymeric films may prove to be suitable for electronic devices based on molecular semiconductors as current fabrication techniques often provide little control over film structure....

46 CFR 109.564 - Maneuvering characteristics.

Science.gov (United States)

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Maneuvering characteristics. 109.564 Section 109.564 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS Miscellaneous § 109.564 Maneuvering characteristics. (a) The master or person in charge of each...

Characterization and correction of charge-induced pixel shifts in DECam

Energy Technology Data Exchange (ETDEWEB)

Gruen, D.; Bernstein, G. M.; Jarvis, M.; Rowe, B.; Vikram, V.; Plazas, A. A.; Seitz, S.

2015-05-01

Interaction of charges in CCDs with the already accumulated charge distribution causes both a flux dependence of the point-spread function (an increase of observed size with flux, also known as the brighter/fatter effect) and pixel-to-pixel correlations of the {Poissonian} noise in flat fields. We describe these effects in the Dark Energy Camera (DECam) with charge dependent shifts of effective pixel borders, i.e. the Antilogus et al. (2014) model, which we fit to measurements of flat-field {Poissonian} noise correlations. The latter fall off approximately as a power-law r(-)(2.5) with pixel separation r, are isotropic except for an asymmetry in the direct neighbors along rows and columns, are stable in time, and are weakly dependent on wavelength. They show variations from chip to chip at the 20% level that correlate with the silicon resistivity. The charge shifts predicted by the model cause biased shape measurements, primarily due to their effect on bright stars, at levels exceeding weak lensing science requirements. We measure the flux dependence of star images and show that the effect can be mitigated by applying the reverse charge shifts at the pixel level during image processing. Differences in stellar size, however, remain significant due to residuals at larger distance from the centroid.

Effect of magnetic field on charge imbalance relaxation of non-equilibrium superconductivity

International Nuclear Information System (INIS)

Tsuboi, Kazuki; Yagi, Ryuta

2010-01-01

We have studied relaxation of charge imbalance of non-equilibrium superconductivity in magnetic field. We found that excess current due to charge imbalance showed striking dependence on magnitude of magnetic field and its orientation. We discussed origin of the relaxation.

Response of electrostatic probes to eccentric charge distributions

DEFF Research Database (Denmark)

Johansson, Torben; McAllister, Iain Wilson

2001-01-01

The response of an electrostatic probe mounted in an electrode is examined with reference to eccentric charge distributions. The study involves using the probe λ function to derive a characteristic parameter. This parameter enables the response of the probe to different degrees of eccentricity...

Costs, charges, and revenues for hospital diagnostic imaging procedures: differences by modality and hospital characteristics.

Science.gov (United States)

Sistrom, Christopher Lee; McKay, Niccie L

2005-06-01

This study examined financial data reported by Florida hospitals concerning costs, charges, and revenues related to imaging services. Financial reports to the Florida Hospital Uniform Reporting System by all licensed acute care facilities for fiscal year 2002 were used to calculate four financial indices on a per procedure basis. These included charge, net revenue, operating expense (variable cost), and contribution margin. Analysis, stratified by cost center (imaging modality), tested the effects of bed size, ownership, teaching status, and urban or rural status on the four indices. The mean operating expense and charge per procedure were as follows: computed tomography (CT): $51 and $1565; x-ray and ultrasound: $55 and $410; nuclear medicine (NM): $135 and $1138; and magnetic resonance imaging (MRI): $165 and $2048. With all four modalities, for-profit hospitals had higher charges than not-for-profit and public facilities. Excepting NM, however, the difference by ownership disappeared when considering net revenue. Operating expense did not differ by ownership type or bed size. Operating expense (variable cost) per procedure is considerably lower for CT than for MRI. Consequently, when diagnostically equivalent, CT is preferable to MRI in terms of costs for hospitals. If the cost structure of nonhospital imaging is at all similar to hospitals, the profit potential for performing CT and MRI seems to be substantial, which has relevance to the issue of imaging self-referral.

Measurement of the spatial specific impulse distribution due to buried high explosive charge detonation

Directory of Open Access Journals (Sweden)

V. Denefeld

2017-06-01

The momentum transfer to a vehicle depends on a number of influencing factors such as: charge mass, embedding material (e.g. sand, gravel, clay, density, water content, saturation, depth of burial, ground clearance and vehicle shape. The presented technology is applied to quantify the influence of the embedding material (alluvial sand, quartz sand, the burial depth and the water content on the local specific impulse distribution. The obtained data can be used as initial condition for the numerical simulation of occupant safety assessment and as input for empirical modeling of momentum transfer on structures.

Charging of mesospheric aerosol particles: the role of photodetachment and photoionization from meteoric smoke and ice particles

Directory of Open Access Journals (Sweden)

M. Rapp

2009-06-01

Full Text Available Time constants for photodetachment, photoemission, and electron capture are considered for two classes of mesospheric aerosol particles, i.e., meteor smoke particles (MSPs and pure water ice particles. Assuming that MSPs consist of metal oxides like Fe₂O₃ or SiO, we find that during daytime conditions photodetachment by solar photons is up to 4 orders of magnitude faster than electron attachment such that MSPs cannot be negatively charged in the presence of sunlight. Rather, even photoemission can compete with electron capture unless the electron density becomes very large (>>1000 cm⁻³ such that MSPs should either be positively charged or neutral in the case of large electron densities. For pure water ice particles, however, both photodetachment and photoemission are negligible due to the wavelength characteristics of its absorption cross section and because the flux of solar photons has already dropped significantly at such short wavelengths. This means that water ice particles should normally be negatively charged. Hence, our results can readily explain the repeated observation of the coexistence of positive and negative aerosol particles in the polar summer mesopause, i.e., small MSPs should be positively charged and ice particles should be negatively charged. These results have further important implications for our understanding of the nucleation of mesospheric ice particles as well as for the interpretation of incoherent scatter radar observations of MSPs.

Electrostatic plasma lens for focusing negatively charged particle beams.

Science.gov (United States)

Goncharov, A A; Dobrovolskiy, A M; Dunets, S M; Litovko, I V; Gushenets, V I; Oks, E M

2012-02-01

We describe the current status of ongoing research and development of the electrostatic plasma lens for focusing and manipulating intense negatively charged particle beams, electrons, and negative ions. The physical principle of this kind of plasma lens is based on magnetic isolation electrons providing creation of a dynamical positive space charge cloud in shortly restricted volume propagating beam. Here, the new results of experimental investigations and computer simulations of wide-aperture, intense electron beam focusing by plasma lens with positive space charge cloud produced due to the cylindrical anode layer accelerator creating a positive ion stream towards an axis system is presented.

Space charge beam dynamics studies for a pulsed spallation source accelerator

Energy Technology Data Exchange (ETDEWEB)

Cho, Y.; Lessner, E.

1995-12-31

Feasibility studies for 2-GeV, 1-MW and 10-GeV, 5-MW rapid cycling synchrotrons (RCS) for spallation neutron sources have been completed. Both synchrotrons operate at a repetition rate of 30 Hz, and accelerate 1.04 {times} 10{sup 14} protons per pulse. The injection energy of the 2-GeV ring is 400 MeV, and the 10-GeV RCS accepts the beam from the 2-GeV machine. Work performed to-date includes calculation of the longitudinal space charge effects in the 400-MeV beam transfer line, and of both longitudinal and transverse space charge effects during the injection, capture and acceleration processes in the two rings. Results of space charge calculations in the rings led to proper choices of the working points and of rf voltage programs that prevents beam loss. Space charge effects in the 2-GeV synchrotron, in both transverse and longitudinal phase space, have major impact on the design due to the fact that the injection energy is 400 MeV. The design achieves the required performance while alleviating harmful effects due to space charge.

Circuit for Full Charging of Series Lithium-Ion Cells

Science.gov (United States)

Ott, William E.; Saunders, David L.

2007-01-01

An advanced charger has been proposed for a battery that comprises several lithium-ion cells in series. The proposal is directed toward charging the cells in as nearly an optimum manner as possible despite unit-to-unit differences among the nominally identical cells. The particular aspect of the charging problem that motivated the proposal can be summarized as follows: During bulk charging (charging all the cells in series at the same current), the voltages of individual cells increase at different rates. Once one of the cells reaches full charge, bulk charging must be stopped, leaving other cells less than fully charged. To make it possible to bring all cells up to full charge once bulk charging has been completed, the proposed charger would include a number of top-off chargers one for each cell. The top-off chargers would all be powered from the same DC source, but their outputs would be DC-isolated from each other and AC-coupled to their respective cells by means of transformers, as described below. Each top-off charger would include a flyback transformer, an electronic switch, and an output diode. For suppression of undesired electromagnetic emissions, each top-off charger would also include (1) a resistor and capacitor configured to act as a snubber and (2) an inductor and capacitor configured as a filter. The magnetic characteristics of the flyback transformer and the duration of its output pulses determine the energy delivered to the lithium-ion cell. It would be necessary to equip the cell with a precise voltage monitor to determine when the cell reaches full charge. In response to a full-charge reading by this voltage monitor, the electronic switch would be held in the off state. Other cells would continue to be charged similarly by their top-off chargers until their voltage monitors read full charge.

Conduction mechanism of leakage current due to the traps in ZrO2 thin film

International Nuclear Information System (INIS)

Seo, Yohan; Lee, Sangyouk; An, Ilsin; Jeong, Heejun; Song, Chulgi

2009-01-01

In this work, a metal-oxide-semiconductor capacitor with zirconium oxide (ZrO 2 ) gate dielectric was fabricated by an atomic layer deposition (ALD) technique and the leakage current characteristics under negative bias were studied. From the result of current–voltage curves there are two possible conduction mechanisms to explain the leakage current in the ZrO 2 thin film. The dominant mechanism is the space charge limited conduction in the high-electric field region (1.5–5.0 MV cm −1 ) while the trap-assisted tunneling due to the existence of traps is prevailed in the low-electric field region (0.8–1.5 MV cm −1 ). Conduction caused by the trap-assisted tunneling is found from the experimental results of a weak temperature dependence of current, and the trap barrier height is obtained. The space charge limited conduction is evidenced, for different temperatures, by Child's law dependence of current density versus voltage. Child's law dependence can be explained by considering a single discrete trapping level and we can obtain the activation energy of 0.22 eV

Conduction mechanism of leakage current due to the traps in ZrO2 thin film

Science.gov (United States)

Seo, Yohan; Lee, Sangyouk; An, Ilsin; Song, Chulgi; Jeong, Heejun

2009-11-01

In this work, a metal-oxide-semiconductor capacitor with zirconium oxide (ZrO2) gate dielectric was fabricated by an atomic layer deposition (ALD) technique and the leakage current characteristics under negative bias were studied. From the result of current-voltage curves there are two possible conduction mechanisms to explain the leakage current in the ZrO2 thin film. The dominant mechanism is the space charge limited conduction in the high-electric field region (1.5-5.0 MV cm-1) while the trap-assisted tunneling due to the existence of traps is prevailed in the low-electric field region (0.8-1.5 MV cm-1). Conduction caused by the trap-assisted tunneling is found from the experimental results of a weak temperature dependence of current, and the trap barrier height is obtained. The space charge limited conduction is evidenced, for different temperatures, by Child's law dependence of current density versus voltage. Child's law dependence can be explained by considering a single discrete trapping level and we can obtain the activation energy of 0.22 eV.

Discrete space charge affected field emission: Flat and hemisphere emitters

Energy Technology Data Exchange (ETDEWEB)

Jensen, Kevin L., E-mail: kevin.jensen@nrl.navy.mil [Code 6854, Naval Research Laboratory, Washington, DC 20375 (United States); Shiffler, Donald A.; Tang, Wilkin [Air Force Research Laboratory, Kirtland AFB, New Mexico 87117 (United States); Rittersdorf, Ian M. [Code 6770, Naval Research Laboratory, Washington, DC 20375 (United States); Lebowitz, Joel L. [Department of Mathematics and Department of Physics, Rutgers University, Piscataway, New Jersey 08854-8019 (United States); Harris, John R. [U.S. Navy Reserve, New Orleans, Louisiana 70143 (United States); Lau, Y. Y. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States); Petillo, John J. [Leidos, Billerica, Massachusetts 01821 (United States); Luginsland, John W. [Physics and Electronics Directorate, AFOSR, Arlington, Virginia 22203 (United States)

2015-05-21

Models of space-charge affected thermal-field emission from protrusions, able to incorporate the effects of both surface roughness and elongated field emitter structures in beam optics codes, are desirable but difficult. The models proposed here treat the meso-scale diode region separate from the micro-scale regions characteristic of the emission sites. The consequences of discrete emission events are given for both one-dimensional (sheets of charge) and three dimensional (rings of charge) models: in the former, results converge to steady state conditions found by theory (e.g., Rokhlenko et al. [J. Appl. Phys. 107, 014904 (2010)]) but show oscillatory structure as they do. Surface roughness or geometric features are handled using a ring of charge model, from which the image charges are found and used to modify the apex field and emitted current. The roughness model is shown to have additional constraints related to the discrete nature of electron charge. The ability of a unit cell model to treat field emitter structures and incorporate surface roughness effects inside a beam optics code is assessed.

Charging-delay induced dust acoustic collisionless shock wave: Roles of negative ions

International Nuclear Information System (INIS)

Ghosh, Samiran; Bharuthram, R.; Khan, Manoranjan; Gupta, M. R.

2006-01-01

The effects of charging-delay and negative ions on nonlinear dust acoustic waves are investigated. It has been found that the charging-delay induced anomalous dissipation causes generation of dust acoustic collisionless shock waves in an electronegative dusty plasma. The small but finite amplitude wave is governed by a Korteweg-de Vries Burger equation in which the Burger term arises due to the charging-delay. Numerical investigations reveal that the charging-delay induced dissipation and shock strength decreases (increases) with the increase of negative ion concentration (temperature)

Infinite stochastic acceleration of charged particles from non-relativistic initial energies

International Nuclear Information System (INIS)

Buts, V.A.; Manujlenko, O.V.; Turkin, Yu.A.

1997-01-01

Stochastic charged particle acceleration by electro-magnetic field due to overlapping of non-linear cyclotron resonances is considered. It was shown that non-relativistic charged particles are involved in infinitive stochastic acceleration regime. This effect can be used for stochastic acceleration or for plasma heating by regular electro-magnetic fields

Selective containment in EBIS for charge breeding applications

International Nuclear Information System (INIS)

Variale, Vincenzo; Valentino, Vincenzo; Bak, Petr A.; Kuznetsov, Gennady I.; Skarbo, Boris; Tiunov, Michael A.; Clauser, Tarcisio; Boggia, Antonio; Raino, Antonio C.

2008-01-01

The production of radioactive ion beam (RIB) with the ISOL technique could require a charge breeder device to increase the ion acceleration efficiency and reduce greatly the production cost. The 'charge breeder' is a device designed to accept radioactive 1+ ions in order to increase their charge state up to n+. In the framework of the SPES project, proposed at the INFN-LNL (Padua) for RIB production, an R and D experiment of a charge breeder device, BRIC, has been carried out at LNL. BRIC is an EBIS-type ion charge state breeder in which a radio frequency (RF) quadrupolar field has been superimposed in the trapped ion region to introduce a selective containment with the aim of increasing the ion trapping efficiency. In this paper, the device and the test measurements that demonstrate the selective containment effect due to the RF quadrupolar field are presented. Furthermore, some comments on the possibility of using that device as charge state breeder for RIB production has been also discussed in the conclusions. This experiment has been also considered as R and D program of the RIB European project EURISOL D S

Stress Induced Charge-Ordering Process in LiMn_2O_4

International Nuclear Information System (INIS)

Chen, Yan; Yu, Dunji; An, Ke

2016-01-01

In this letter we report the stress-induced Mn charge-ordering process in the LiMn_2O_4 spinel, evidenced by the lattice strain evolutions due to the Jahn–Teller effects. In situ neutron diffraction reveals the initial stage of this process at low stress, indicating the eg electron localization at the preferential Mn sites during the early phase transition as an underlying charge-ordering mechanism in the charge-frustrated LiMn_2O_4. The initial stage of this transition exhibits as a progressive lattice and charge evolution, without showing a first-order behavior.

Density-dependent coupling constants and charge symmetry breaking

International Nuclear Information System (INIS)

Barreiro, L.A.

2001-01-01

The effect of the medium in the coupling constants implicate in a charge symmetry breaking on nuclear interactions. The amount of energy due to this modification can explain the Nolen-Schiffer anomaly. (author)

Effect of nitrogen plasma afterglow on the surface charge effect resulted during XPS surface analysis of amorphous carbon nitride thin films

Science.gov (United States)

Kayed, Kamal

2018-06-01

The aim of this paper is to investigate the relationship between the micro structure and the surface charge effect resulted during XPS surface analysis of amorphous carbon nitride thin films prepared by laser ablation method. The study results show that the charge effect coefficient (E) is not just a correction factor. We found that the changes in this coefficient value due to incorporation of nitrogen atoms into the carbon network are related to the spatial configurations of the sp2 bonded carbon atoms, order degree and sp2 clusters size. In addition, results show that the curve E vs. C(sp3)-N is a characteristic curve of the micro structure. This means that using this curve makes it easy to sorting the samples according to the micro structure (hexagonal rings or chains).

Large tunable image-charge effects in single-molecule junctions.

NARCIS (Netherlands)

Perrin, M.L.; Verzijl, C.J.; Martin, C.A.; Shaikh, A.J.; Eelkema, R.; Esch, J.H. van; Ruitenbeek, J.M. van; Thijssen, J.M.; Zant, H.S. van der; Dulic, D.

2013-01-01

Metal/organic interfaces critically determine the characteristics of molecular electronic devices, because they influence the arrangement of the orbital levels that participate in charge transport. Studies on self-assembled monolayers show molecule-dependent energy-level shifts as well as

Aberration of a negative ion beam caused by space charge effect

International Nuclear Information System (INIS)

Miyamoto, K.; Wada, S.; Hatayama, A.

2010-01-01

Aberrations are inevitable when the charged particle beams are extracted, accelerated, transmitted, and focused with electrostatic and magnetic fields. In this study, we investigate the aberration of a negative ion accelerator for a neutral beam injector theoretically, especially the spherical aberration caused by the negative ion beam expansion due to the space charge effect. The negative ion current density profiles with the spherical aberration are compared with those without the spherical aberration. It is found that the negative ion current density profiles in a log scale are tailed due to the spherical aberration.

Aberration of a negative ion beam caused by space charge effect

Energy Technology Data Exchange (ETDEWEB)

Miyamoto, K. [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Wada, S.; Hatayama, A. [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)

2010-02-15

Aberrations are inevitable when the charged particle beams are extracted, accelerated, transmitted, and focused with electrostatic and magnetic fields. In this study, we investigate the aberration of a negative ion accelerator for a neutral beam injector theoretically, especially the spherical aberration caused by the negative ion beam expansion due to the space charge effect. The negative ion current density profiles with the spherical aberration are compared with those without the spherical aberration. It is found that the negative ion current density profiles in a log scale are tailed due to the spherical aberration.

Aberration of a negative ion beam caused by space charge effect.

Science.gov (United States)

Miyamoto, K; Wada, S; Hatayama, A

2010-02-01

Aberrations are inevitable when the charged particle beams are extracted, accelerated, transmitted, and focused with electrostatic and magnetic fields. In this study, we investigate the aberration of a negative ion accelerator for a neutral beam injector theoretically, especially the spherical aberration caused by the negative ion beam expansion due to the space charge effect. The negative ion current density profiles with the spherical aberration are compared with those without the spherical aberration. It is found that the negative ion current density profiles in a log scale are tailed due to the spherical aberration.

Charging dynamics and strong localization of a two-dimensional electron cloud

International Nuclear Information System (INIS)

Dianoux, R; Smilde, H J H; Marchi, F; Buffet, N; Mur, P; Comin, F; Chevrier, J

2007-01-01

The dynamics of charge injection in silicon nanocrystals embedded in a silicon dioxide matrix is studied using electrostatic force microscopy. We show that the presence of silicon nanocrystals with a density of 10 11 cm -2 is essential for strong localization of charges, and results in exceptional charge retention properties compared to nanocrystal-free SiO 2 samples. In both systems, a logarithmic dependence of the diameter of the charged area on the injection time is experimentally observed on a timescale between 0.1 and 10 s (voltage≤10 V). A field-emission injection, limited by Coulomb blockade and a lateral charge spreading due to a repulsive radial electric field are used to model the sample charging. Once the tip is retracted, the electron cloud is strongly confined in the nanocrystals and remains static

The measurement and modeling of alpha-particle-induced charge collection in dynamic memories

International Nuclear Information System (INIS)

Oldiges, P.J.

1989-01-01

This thesis addresses the problem of α-particle-induced charge collection in high-density dynamic random access memories. A novel technique for the measurement of charge collection in high-density memory cells and bit lines due to α-particle strikes was developed. The technique involves D.C. tests on simple test structures with an α-particle source on the device package as a lid. The advantages of this new measurement technique are: the method allows for in-situ measurements of charge collection on both MOS capacitors and bit lines found in present-day memories; the on-chip measurement technique minimizes errors due to external probes loading the device under test; the measurements can be controlled by a personal computer, with the data being able to be reduced on the same machine. Results obtained using this new measurement technique show that the charge collection is found to depend upon test-structure size and the configuration of its neighbors. Results of two-dimensional simulations of charge flow along the surface of an MOS capacitor from current injection due to an α-particle strike indicate that a spatial potential variation of 0.5V may occur between the point of current injection and capacitor edge for a 1M dRAM capacitor

Investigation of spray characteristics from a low-pressure common rail injector for use in a homogeneous charge compression ignition engine

Science.gov (United States)

Lee, Kihyung; Reitz, Rolf D.

2004-03-01

Homogeneous charge compression ignition (HCCI) combustion provides extremely low levels of pollutant emissions, and thus is an attractive alternative for future IC engines. In order to achieve a uniform mixture distribution within the engine cylinder, the characteristics of the fuel spray play an important role in the HCCI engine concept. It is well known that high-pressure common rail injection systems, mainly used in diesel engines, achieve poor mixture formation because of the possibility of direct fuel impingement on the combustion chamber surfaces. This paper describes spray characteristics of a low-pressure common rail injector which is intended for use in an HCCI engine. Optical diagnostics including laser diffraction and phase Doppler methods, and high-speed camera photography, were applied to measure the spray drop diameter and to investigate the spray development process. The drop sizing results of the laser diffraction method were compared with those of a phase Doppler particle analyser (PDPA) to validate the accuracy of the experiments. In addition, the effect of fuel properties on the spray characteristics was investigated using n-heptane, Stoddard solvent (gasoline surrogate) and diesel fuel because HCCI combustion is sensitive to the fuel composition. The results show that the injector forms a hollow-cone sheet spray rather than a liquid jet, and the atomization efficiency is high (small droplets are produced). The droplet SMD ranged from 15 to 30 µm. The spray break-up characteristics were found to depend on the fuel properties. The break-up time for n-heptane is shorter and the drop SMD is smaller than that of Stoddard solvent and diesel fuel.

Charging effects of PET under electron beam irradiation in a SEM

International Nuclear Information System (INIS)

Jbara, O; Rondot, S; Hadjadj, A; Patat, J M; Fakhfakh, S; Belhaj, M

2008-01-01

This paper deals with charge trapping and charge transport of polyethylene terephthalate (PET) polymer subjected to electron irradiation in a scanning electron microscope (SEM). Measurement of displacement current and leakage current using an arrangement adapted to the SEM allows the amount of trapped charge during and after electron irradiation to be determined and the charge mechanisms regulation to be studied. These mechanisms involve several parameters related to the electronic injection, the characteristics of insulator and the effects of the trapped charge itself. The dynamic trapping properties of PET samples are investigated and the time constants of charging are evaluated for various conditions of irradiation. The determination of the trapping cross section for electrons is possible by using the trapping rate at the onset of irradiation. Many physical processes are involved in the charging and discharging mechanisms; among them surface conduction is outlined. Through the control of irradiation conditions, various types of surface discharging (flashover phenomenon) behaviour are also observed. The strength of the electric field initiating surface discharge is estimated.

Charge sensitive amplifies. The state of arts

Energy Technology Data Exchange (ETDEWEB)

Mori, Kunishiro [Clear Pulse Co., Tokyo (Japan)

1996-07-01

In the radiation detectors, signals are essentially brought with charges produced by radiation, then it is naturally the best way to use a charge sensitive amplifier (CSA) system to extract those signals. The CSA is thought to be the best amplifier suitable to almost all the radiation detectors, if neglecting economical points of view. The CSA has been only applied to special fields like radiation detection because the concept of `charges` is not so universal against the concepts of `voltage` and `current`. The CSA, however, is low in noise and a high speed amplifier and may be applicable not only to radiation measurement but also piezoelectric devices and also bolometers. In this article, noise in the CSA, basic circuit on the CSA, concepts of `equivalent noise charge` (ENC), a method for the ENC, and importance of the `open-loop gain` in the CSA to achieve better performance of it and how to realize in a practical CSA were described. And, characteristics on a counting rate of the CSA, various circuit used in the CSA, and CSAs which are commercially available at present and special purpose CSAs were also introduced. (G.K.)

Simulating Electrophoresis with Discrete Charge and Drag

Science.gov (United States)

Mowitz, Aaron J.; Witten, Thomas A.

A charged asymmetric rigid cluster of colloidal particles in saline solution can respond in exotic ways to an electric field: it may spin or move transversely. These distinctive motions arise from the drag force of the neutralizing countercharge surrounding the cluster. Because of this drag, calculating the motion of arbitrary asymmetric objects with nonuniform charge is impractical by conventional methods. Here we present a new method of simulating electrophoresis, in which we replace the continuous object and the surrounding countercharge with discrete point-draggers, called Stokeslets. The balance of forces imposes a linear, self-consistent relation among the drag and Coulomb forces on the Stokeslets, which allows us to easily determine the object's motion via matrix inversion. By explicitly enforcing charge+countercharge neutrality, the simulation recovers the distinctive features of electrophoretic motion to few-percent accuracy using as few as 1000 Stokeslets. In particular, for uniformly charged objects, we observe the characteristic Smoluchowski independence of mobility on object size and shape. We then discuss electrophoretic motion of asymmetric objects, where our simulation method is particularly advantageous. This work is supported by a Grant from the US-Israel Binational Science Foundation.

Charge-fluctuation-induced heating of dust particles in a plasma.

Science.gov (United States)

Vaulina, O S; Khrapak, S A; Nefedov, A P; Petrov, O F

1999-11-01

Random charge fluctuations are always present in dusty plasmas due to the discrete nature of currents charging the dust particle. These fluctuations can be a reason for the heating of the dust particle system. Such unexpected heating leading to the melting of the dust crystals was observed recently in several experiments. In this paper we show by analytical evaluations and numerical simulation that charge fluctuations provide an effective source of energy and can heat the dust particles up to several eV, in conditions close to experimental ones.

Effect of surface topography and morphology on space charge packets in polyethylene

International Nuclear Information System (INIS)

Zhou Yuanxiang; Wang Yunshan; Sun Qinghua; Wang Ninghua

2009-01-01

Polyethylene (PE) is a major kind of internal insulating material. With great progresses of space charge measurement technologies in the last three decades, lots of researches are focused on space charge in PE. The heat pressing and annealing condition of polyethylene affect its morphology obviously. During the heat pressing, the surface of PE forms different surface topographies because of different substrate materials. Surface topography has great relation to the epitaxial crystallization layer and influences the space charge characteristic of PE dramatically. This paper studied the formation process of different surface topographies and their micrographic characters in low density polyethylene (LDPE). pulsed electro-acoustic (PEA) method was used to measure the space charge distribution of samples with different surface topographies and morphologies in LDPE. The effect of surface topography and morphology to space charge packet were studied. The surface topography has great influence on space charge packet polarity and morphology has influence on both movement speed rate and polarity of space charge packet.

High-resolution x-ray scattering studies of charge ordering in highly correlated electron systems

International Nuclear Information System (INIS)

Ghazi, M.E.

2002-01-01

Many important properties of transition metal oxides such as, copper oxide high-temperature superconductivity and colossal magnetoresistance (CMR) in manganites are due to strong electron-electron interactions, and hence these systems are called highly correlated systems. These materials are characterised by the coexistence of different kinds of order, including charge, orbital, and magnetic moment. This thesis contains high-resolution X-ray scattering studies of charge ordering in such systems namely the high-T C copper oxides isostructural system, La 2-x Sr x NiO 4 with various Sr concentrations (x = 0.33 - 0.2), and the CMR manganite system, Nd 1/2 Sr 1/2 MnO 3 . It also includes a review of charge ordering in a large variety of transition metal oxides, such as ferrates, vanadates, cobaltates, nickelates, manganites, and cuprates systems, which have been reported to date in the scientific literature. Using high-resolution synchrotron X-ray scattering, it has been demonstrated that the charge stripes exist in a series of single crystals of La 2-x Sr x NiO 4 with Sr concentrations (x = 0.33 - 0.2) at low temperatures. Satellite reflections due to the charge ordering were found with the wavevector (2ε, 0, 1) below the charge ordering transition temperature, T CO , where 2ε is the amount of separation from the corresponding Bragg peak. The charge stripes are shown to be two-dimensional in nature both by measurements of their correlation lengths and by measurement of the critical exponents of the charge stripe melting transition with an anomaly at x = 0.25. The results show by decreasing the hole concentration from the x = 0.33 to 0.2, the well-correlated charge stripes change to a glassy state at x = 0.25. The electronic transition into the charge stripe phase is second-order without any corresponding structural transition. Above the second-order transition critical scattering was observed due to fluctuations into the charge stripe phase. In a single-crystal of Nd

The Schottky energy barrier dependence of charge injection in organic light-emitting diodes

Science.gov (United States)

Campbell, I. H.; Davids, P. S.; Smith, D. L.; Barashkov, N. N.; Ferraris, J. P.

1998-04-01

We present device model calculations of the current-voltage (I-V) characteristics of organic diodes and compare them with measurements of structures fabricated using MEH-PPV. The structures are designed so that all of the current is injected from one contact. The I-V characteristics are considered as a function of the Schottky energy barrier to charge injection from the contact. Experimentally, the Schottky barrier is varied from essentially zero to more than 1 eV by using different metal contacts. A consistent description of the device I-V characteristics is obtained as the Schottky barrier is varied from small values, less than about 0.4 eV, where the current flow is space-charge limited to larger values where it is contact limited.

Charge reconstruction in large-area photomultipliers

Science.gov (United States)

Grassi, M.; Montuschi, M.; Baldoncini, M.; Mantovani, F.; Ricci, B.; Andronico, G.; Antonelli, V.; Bellato, M.; Bernieri, E.; Brigatti, A.; Brugnera, R.; Budano, A.; Buscemi, M.; Bussino, S.; Caruso, R.; Chiesa, D.; Corti, D.; Dal Corso, F.; Ding, X. F.; Dusini, S.; Fabbri, A.; Fiorentini, G.; Ford, R.; Formozov, A.; Galet, G.; Garfagnini, A.; Giammarchi, M.; Giaz, A.; Insolia, A.; Isocrate, R.; Lippi, I.; Longhitano, F.; Lo Presti, D.; Lombardi, P.; Marini, F.; Mari, S. M.; Martellini, C.; Meroni, E.; Mezzetto, M.; Miramonti, L.; Monforte, S.; Nastasi, M.; Ortica, F.; Paoloni, A.; Parmeggiano, S.; Pedretti, D.; Pelliccia, N.; Pompilio, R.; Previtali, E.; Ranucci, G.; Re, A. C.; Romani, A.; Saggese, P.; Salamanna, G.; Sawy, F. H.; Settanta, G.; Sisti, M.; Sirignano, C.; Spinetti, M.; Stanco, L.; Strati, V.; Verde, G.; Votano, L.

2018-02-01

Large-area PhotoMultiplier Tubes (PMT) allow to efficiently instrument Liquid Scintillator (LS) neutrino detectors, where large target masses are pivotal to compensate for neutrinos' extremely elusive nature. Depending on the detector light yield, several scintillation photons stemming from the same neutrino interaction are likely to hit a single PMT in a few tens/hundreds of nanoseconds, resulting in several photoelectrons (PEs) to pile-up at the PMT anode. In such scenario, the signal generated by each PE is entangled to the others, and an accurate PMT charge reconstruction becomes challenging. This manuscript describes an experimental method able to address the PMT charge reconstruction in the case of large PE pile-up, providing an unbiased charge estimator at the permille level up to 15 detected PEs. The method is based on a signal filtering technique (Wiener filter) which suppresses the noise due to both PMT and readout electronics, and on a Fourier-based deconvolution able to minimize the influence of signal distortions—such as an overshoot. The analysis of simulated PMT waveforms shows that the slope of a linear regression modeling the relation between reconstructed and true charge values improves from 0.769 ± 0.001 (without deconvolution) to 0.989 ± 0.001 (with deconvolution), where unitary slope implies perfect reconstruction. A C++ implementation of the charge reconstruction algorithm is available online at [1].

The magnetic field generated by a rotating charged polygon

International Nuclear Information System (INIS)

Wan, Songlin; Chen, Xiangyu; Teng, Baohua; Fu, Hao; Li, Yefeng; Wu, Minghe; Wu, Shaoyi; Balfour, E A

2014-01-01

The magnetic field along the symmetry axis of a regular polygon carrying a uniform electric charge on its edges is calculated systematically when the polygon is rotated about this axis of symmetry. A group of circular current-carrying coils arranged concentrically about the axis of the polygon has been designed to simulate the magnetic field characteristics of the rotating charged polygon. The magnetic field of the simulated coils is measured using the PASCO magnetic field sensor. The results show that the theoretical calculation agrees well with the experimental results. (paper)

Emission Characteristics for a Homogeneous Charged Compression Ignition Diesel Engine with Exhaust Gas Recirculation Using Split Injection Methodology

Directory of Open Access Journals (Sweden)

Changhee Lee

2017-12-01

Full Text Available Due to the serious issues caused by air pollution and global warming, emission regulations are becoming stricter. New technologies that reduce NOx and PM emissions are needed. To cope with these social exhaust gas regulation demands, many advanced countries are striving to develop eco-friendly vehicles in order to respond to stricter emissions regulations. The homogeneous charged compression ignition engine (HCCI incorporates a multi-stage combustion engine with multiple combustion modes, catalyst, direct fuel injection and partial mixing combustion. In this study, the HCCI combustion was applied to analyze and review the results of engines applying HCCI combustion without altering the conventional engine specifications. The optimization of exhaust gas recirculation (EGR and compression ratio changes provides an optimal fuel economy. In this study, potential for optimum economy within the range of IMEP 0.8 MPa has been evaluated.

Deposition of Aerosol Particles in Electrically Charged Membrane Filters

Energy Technology Data Exchange (ETDEWEB)

Stroem, L

1972-05-15

A theory for the influence of electric charge on particle deposition on the surface of charged filters has been developed. It has been tested experimentally on ordinary membrane filters and Nuclepore filters of 8 mum pore size, with a bipolar monodisperse test aerosol of 1 mum particle diameter, and at a filter charge up to 20 muC/m2. Agreement with theory was obtained for the Coulomb force between filter and particle for both kinds of filters. The image force between charged filter and neutral particles did not result in the predicted deposition in the ordinary membrane filter, probably due to lacking correspondence between the filter model employed for the theory, and the real filter. For the Nuclepore filter a satisfactory agreement with theory was obtained, also at image interaction

Nonadiabatic charged spherical evolution in the postquasistatic approximation

International Nuclear Information System (INIS)

Rosales, L.; Barreto, W.; Peralta, C.; Rodriguez-Mueller, B.

2010-01-01

We apply the postquasistatic approximation, an iterative method for the evolution of self-gravitating spheres of matter, to study the evolution of dissipative and electrically charged distributions in general relativity. The numerical implementation of our approach leads to a solver which is globally second-order convergent. We evolve nonadiabatic distributions assuming an equation of state that accounts for the anisotropy induced by the electric charge. Dissipation is described by streaming-out or diffusion approximations. We match the interior solution, in noncomoving coordinates, with the Vaidya-Reissner-Nordstroem exterior solution. Two models are considered: (i) a Schwarzschild-like shell in the diffusion limit; and (ii) a Schwarzschild-like interior in the free-streaming limit. These toy models tell us something about the nature of the dissipative and electrically charged collapse. Diffusion stabilizes the gravitational collapse producing a spherical shell whose contraction is halted in a short characteristic hydrodynamic time. The streaming-out radiation provides a more efficient mechanism for emission of energy, redistributing the electric charge on the whole sphere, while the distribution collapses indefinitely with a longer hydrodynamic time scale.

Electron holography study of the charging effect in microfibrils of sciatic nerve tissues.

Science.gov (United States)

Kim, Ki Hyun; Akase, Zentaro; Shindo, Daisuke; Ohno, Nobuhiko; Fujii, Yasuhisa; Terada, Nobuo; Ohno, Shinichi

2013-08-01

The charging effects of microfibrils of sciatic nerve tissues due to electron irradiation are investigated using electron holography. The phenomenon that the charging effects are enhanced with an increase of electron intensity is visualized through direct observations of the electric potential distribution around the specimen. The electric potential at the surface of the specimen could be quantitatively evaluated by simulation, which takes into account the reference wave modulation due to the long-range electric field.

Charge Transport in LDPE Nanocomposites Part I—Experimental Approach

Directory of Open Access Journals (Sweden)

Anh T. Hoang

2016-03-01

Full Text Available This work presents results of bulk conductivity and surface potential decay measurements on low-density polyethylene and its nanocomposites filled with uncoated MgO and Al2O3, with the aim to highlight the effect of the nanofillers on charge transport processes. Material samples at various filler contents, up to 9 wt %, were prepared in the form of thin films. The performed measurements show a significant impact of the nanofillers on reduction of material’s direct current (dc conductivity. The investigations thus focused on the nanocomposites having the lowest dc conductivity. Various mechanisms of charge generation and transport in solids, including space charge limited current, Poole-Frenkel effect and Schottky injection, were utilized for examining the experimental results. The mobilities of charge carriers were deduced from the measured surface potential decay characteristics and were found to be at least two times lower for the nanocomposites. The temperature dependencies of the mobilities were compared for different materials.

Charge exchange in galaxy clusters

Science.gov (United States)

Gu, Liyi; Mao, Junjie; de Plaa, Jelle; Raassen, A. J. J.; Shah, Chintan; Kaastra, Jelle S.

2018-03-01

Context. Though theoretically expected, the charge exchange emission from galaxy clusters has never been confidently detected. Accumulating hints were reported recently, including a rather marginal detection with the Hitomi data of the Perseus cluster. As previously suggested, a detection of charge exchange line emission from galaxy clusters would not only impact the interpretation of the newly discovered 3.5 keV line, but also open up a new research topic on the interaction between hot and cold matter in clusters. Aim. We aim to perform the most systematic search for the O VIII charge exchange line in cluster spectra using the RGS on board XMM-Newton. Methods: We introduce a sample of 21 clusters observed with the RGS. In order to search for O VIII charge exchange, the sample selection criterion is a >35σ detection of the O VIII Lyα line in the archival RGS spectra. The dominating thermal plasma emission is modeled and subtracted with a two-temperature thermal component, and the residuals are stacked for the line search. The systematic uncertainties in the fits are quantified by refitting the spectra with a varying continuum and line broadening. Results: By the residual stacking, we do find a hint of a line-like feature at 14.82 Å, the characteristic wavelength expected for oxygen charge exchange. This feature has a marginal significance of 2.8σ, and the average equivalent width is 2.5 × 10-4 keV. We further demonstrate that the putative feature can be barely affected by the systematic errors from continuum modeling and instrumental effects, or the atomic uncertainties of the neighboring thermal lines. Conclusions: Assuming a realistic temperature and abundance pattern, the physical model implied by the possible oxygen line agrees well with the theoretical model proposed previously to explain the reported 3.5 keV line. If the charge exchange source indeed exists, we expect that the oxygen abundance could have been overestimated by 8-22% in previous X

Nonuniform charging effects on ion drag force in drifting dusty plasmas

International Nuclear Information System (INIS)

Chang, Dong-Man; Chang, Won-Seok; Jung, Young-Dae

2006-01-01

The nonuniform polarization charging effects on the ion drag force are investigated in drifting dusty plasmas. The ion drag force due to the ion-dust grain interaction is obtained as a function of the dust charge, ion charge, plasma temperature, Mach number, Debye length, and collision energy. The result shows that the nonuniform charging effects enhance the momentum transfer cross section as well as the ion drag force. It is found that the momentum transfer cross section and the ion drag force including nonuniform polarization charging effects increase with increasing the Mach number and also the ion drag force increases with increasing the temperature. In addition, it is found that the ion drag force is slightly decreasing with an increase of the Debye length

A generalized multi-dimensional mathematical model for charging and discharging processes in a supercapacitor

Energy Technology Data Exchange (ETDEWEB)

Allu, Srikanth [ORNL; Velamur Asokan, Badri [Exxon Mobil Research and Engineering; Shelton, William A [Louisiana State University; Philip, Bobby [ORNL; Pannala, Sreekanth [ORNL

2014-01-01

A generalized three dimensional computational model based on unied formulation of electrode- electrolyte-electrode system of a electric double layer supercapacitor has been developed. The model accounts for charge transport across the solid-liquid system. This formulation based on volume averaging process is a widely used concept for the multiphase ow equations ([28] [36]) and is analogous to porous media theory typically employed for electrochemical systems [22] [39] [12]. This formulation is extended to the electrochemical equations for a supercapacitor in a consistent fashion, which allows for a single-domain approach with no need for explicit interfacial boundary conditions as previously employed ([38]). In this model it is easy to introduce the spatio-temporal variations, anisotropies of physical properties and it is also conducive for introducing any upscaled parameters from lower length{scale simulations and experiments. Due to the irregular geometric congurations including porous electrode, the charge transport and subsequent performance characteristics of the super-capacitor can be easily captured in higher dimensions. A generalized model of this nature also provides insight into the applicability of 1D models ([38]) and where multidimensional eects need to be considered. In addition, simple sensitivity analysis on key input parameters is performed in order to ascertain the dependence of the charge and discharge processes on these parameters. Finally, we demonstarted how this new formulation can be applied to non-planar supercapacitors

Charge measurement and mitigation for the main test masses of the GEO 600 gravitational wave observatory

International Nuclear Information System (INIS)

Hewitson, M; Danzmann, K; Grote, H; Hild, S; Hough, J; Lueck, H; Rowan, S; Smith, J R; Strain, K A; Willke, B

2007-01-01

Spurious charging of the test masses in gravitational wave interferometers is a well-known problem. Typically, concern arises due to the possibility of increased thermal noise due to a lowering of the quality factor of modes of the test-mass suspension, or due to the potential for increased displacement noise arising from charge migration on the surface of the test masses. Recent experience gained at the GEO 600 gravitational wave detector has highlighted an additional problem. GEO 600 uses electrostatic actuators to control the longitudinal position of the main test masses. The presence of charge on the test masses is shown to strongly affect the performance of the electrostatic actuators. This paper reports on a measurement scheme whereby the charge state of the GEO 600 test masses can be measured using the electrostatic actuators. The resulting measurements are expressed in terms of an effective bias voltage on the electrostatic actuators. We also describe attempts to remove the charge from the test masses and we show that the use of UV illumination was the most successful. Using UV illumination we were able to discharge and re-charge the test masses

Charge states of ions, and mechanisms of charge ordering transitions

Science.gov (United States)

Pickett, Warren E.; Quan, Yundi; Pardo, Victor

2014-07-01

To gain insight into the mechanism of charge ordering transitions, which conventionally are pictured as a disproportionation of an ion M as 2Mn+→M(n+1)+ + M(n-1)+, we (1) review and reconsider the charge state (or oxidation number) picture itself, (2) introduce new results for the putative charge ordering compound AgNiO2 and the dual charge state insulator AgO, and (3) analyze the cationic occupations of the actual (not formal) charge, and work to reconcile the conundrums that arise. We establish that several of the clearest cases of charge ordering transitions involve no disproportion (no charge transfer between the cations, and hence no charge ordering), and that the experimental data used to support charge ordering can be accounted for within density functional-based calculations that contain no charge transfer between cations. We propose that the charge state picture retains meaning and importance, at least in many cases, if one focuses on Wannier functions rather than atomic orbitals. The challenge of modeling charge ordering transitions with model Hamiltonians isdiscussed.

Core Characteristics Deterioration due to Plastic Deformation

Science.gov (United States)

Kaido, Chikara; Arai, Satoshi

This paper discusses the effect of plastic deformation at core manufacturing on the characteristics of cores where non-oriented electrical steel sheets are used as core material. Exciting field and iron loss increase proportionally to plastic deformation in the case of rPeddy currents increase because plastic deformations of crystalline grains are distributed and then the flux distribution is induced. In the case of rP>20, the deterioration tend to saturate, and the increases in magnetic field and iron loss are 1000 to 1500A/m and 2 to 4W/kg. They are related to grain size, and high grade with larger grain may have lager field increase and smaller iron loss increase. Anomalous eddy current losses scarcely increase in this region. In actual motors, the plastic deformation affects iron loss increase although exciting current increases a little.

Limit on the electric charge of antihydrogen

Energy Technology Data Exchange (ETDEWEB)

Capra, A., E-mail: acapra@triumf.ca; Amole, C. [York University, Department of Physics and Astronomy (Canada); Ashkezari, M. D. [Simon Fraser University, Department of Physics (Canada); Baquero-Ruiz, M. [University of California at Berkeley, Department of Physics (United States); Bertsche, W. [University of Manchester, School of Physics and Astronomy (United Kingdom); Butler, E. [Imperial College, Centre for Cold Matter (United Kingdom); Cesar, C. L. [Universidade Federal do Rio de Janeiro, Instituto de Física (Brazil); Charlton, M.; Eriksson, S. [Swansea University, Department of Physics, College of Science (United Kingdom); Fajans, J. [University of California at Berkeley, Department of Physics (United States); Friesen, T. [University of Calgary, Department of Physics and Astronomy (Canada); Fujiwara, M. C.; Gill, D. R. [TRIUMF (Canada); Gutierrez, A. [University of British Columbia, Department of Physics and Astronomy (Canada); Hangst, J. S. [CERN, Physics Department (Switzerland); Hardy, W. N. [University of British Columbia, Department of Physics and Astronomy (Canada); Hayden, M. E. [Simon Fraser University, Department of Physics (Canada); Isaac, C. A. [Swansea University, Department of Physics, College of Science (United Kingdom); Jonsell, S. [Stockholm University, Department of Physics (Sweden); Kurchaninov, L. [TRIUMF (Canada); and others

2017-11-15

The ALPHA collaboration has successfully demonstrated the production and the confinement of cold antihydrogen, H̅. An analysis of trapping data allowed a stringent limit to be placed on the electric charge of the simplest antiatom. Charge neutrality of matter is known to a very high precision, hence a neutrality limit of H̅ provides a test of CPT invariance. The experimental technique is based on the measurement of the deflection of putatively charged H̅ in an electric field. The tendency for trapped H̅ atoms to be displaced by electrostatic fields is measured and compared to the results of a detailed simulation of H̅ dynamics in the trap. An extensive survey of the systematic errors was performed, and this work focuses on those due to the silicon vertex detector, which is the device used to determine the H̅ annihilation position. The limit obtained on the charge of the H̅ atom is Q = (−1.3 ± 1.8 ± 0.4) × 10{sup −8}, representing the first precision measurement with H̅ [1].

A Uniform Voltage Gain Control for Alignment Robustness in Wireless EV Charging

Directory of Open Access Journals (Sweden)

Yabiao Gao

2015-08-01

Full Text Available The efficiency of wireless power transfer is sensitive to the horizontal and vertical distances between the transmitter and receiver coils due to the magnetic coupling change. To address the output voltage variation and efficiency drop caused by misalignment, a uniform voltage gain frequency control is implemented to improve the power delivery and efficiency of wireless power transfer under misalignment. The frequency is tuned according to the amplitude and phase-frequency characteristics of coupling variations in order to maintain a uniform output voltage in the receiver coil. Experimental comparison of three control methods, including fixed frequency control, resonant frequency control, and the proposed uniform gain control was conducted and demonstrated that the uniform voltage gain control is the most robust method for managing misalignment in wireless charging applications.

Interfacial charge distributions in carbon-supported palladium catalysts

DEFF Research Database (Denmark)

Rao, Radhika G.; Blume, Raoul; Hansen, Thomas Willum

2017-01-01

Controlling the charge transfer between a semiconducting catalyst carrier and the supported transition metal active phase represents an elite strategy for fine turning the electronic structure of the catalytic centers, hence their activity and selectivity. These phenomena have been theoretically...... and experimentally elucidated for oxide supports but remain poorly understood for carbons due to their complex nanoscale structure. Here, we combine advanced spectroscopy and microscopy on model Pd/C samples to decouple the electronic and surface chemistry effects on catalytic performance. Our investigations reveal...... treatments can be used to tune the interfacial charge distribution, hereby providing a strategy to rationally design carbon-supported catalysts.Control over charge transfer in carbon-supported metal nanoparticles is essential for designing new catalysts. Here, the authors show that thermal treatments...

Optimal Charge-to-Spin Conversion in Graphene on Transition-Metal Dichalcogenides

Science.gov (United States)

Offidani, Manuel; Milletarı, Mirco; Raimondi, Roberto; Ferreira, Aires

2017-11-01

When graphene is placed on a monolayer of semiconducting transition metal dichalcogenide (TMD) its band structure develops rich spin textures due to proximity spin-orbital effects with interfacial breaking of inversion symmetry. In this work, we show that the characteristic spin winding of low-energy states in graphene on a TMD monolayer enables current-driven spin polarization, a phenomenon known as the inverse spin galvanic effect (ISGE). By introducing a proper figure of merit, we quantify the efficiency of charge-to-spin conversion and show it is close to unity when the Fermi level approaches the spin minority band. Remarkably, at high electronic density, even though subbands with opposite spin helicities are occupied, the efficiency decays only algebraically. The giant ISGE predicted for graphene on TMD monolayers is robust against disorder and remains large at room temperature.

Microscopic origins of charge transport in triphenylene systems

Science.gov (United States)

Thompson, Ian R.; Coe, Mary K.; Walker, Alison B.; Ricci, Matteo; Roscioni, Otello M.; Zannoni, Claudio

2018-06-01

We study the effects of molecular ordering on charge transport at the mesoscale level in a layer of ≈9000 hexa-octyl-thio-triphenylene discotic mesogens with dimensions of ≈20 ×20 ×60 nm3 . Ordered (columnar) and disordered isotropic morphologies are obtained from a combination of atomistic and coarse-grained molecular-dynamics simulations. Electronic structure codes are used to find charge hopping rates at the microscopic level. Energetic disorder is included through the Thole model. Kinetic Monte Carlo simulations then predict charge mobilities. We reproduce the large increase in mobility in going from an isotropic to a columnar morphology. To understand how these mobilities depend on the morphology and hopping rates, we employ graph theory to analyze charge trajectories by representing the film as a charge-transport network. This approach allows us to identify spatial correlations of molecule pairs with high transfer rates. These pairs must be linked to ensure good transport characteristics or may otherwise act as traps. Our analysis is straightforward to implement and will be a useful tool in linking materials to device performance, for example, to investigate the influence of local inhomogeneities in the current density. Our mobility-field curves show an increasing mobility with field, as would be expected for an organic semiconductor.

State of Charge Estimation Based on Microscopic Driving Parameters for Electric Vehicle's Battery

Directory of Open Access Journals (Sweden)

Enjian Yao

2013-01-01

Full Text Available Recently, battery-powered electric vehicle (EV has received wide attention due to less pollution during use, low noise, and high energy efficiency and is highly expected to improve urban air quality and then mitigate energy and environmental pressure. However, the widespread use of EV is still hindered by limited battery capacity and relatively short cruising range. This paper aims to propose a state of charge (SOC estimation method for EV’s battery necessary for route planning and dynamic route guidance, which can help EV drivers to search for the optimal energy-efficient routes and to reduce the risk of running out of electricity before arriving at the destination or charging station. Firstly, by analyzing the variation characteristics of power consumption rate with initial SOC and microscopic driving parameters (instantaneous speed and acceleration, a set of energy consumption rate models are established according to different operation modes. Then, the SOC estimation model is proposed based on the presented EV power consumption model. Finally, by comparing the estimated SOC with the measured SOC, the proposed SOC estimation method is proved to be highly accurate and effective, which can be well used in EV route planning and navigation systems.

Battery charging control methods, electric vehicle charging methods, battery charging apparatuses and rechargeable battery systems

Science.gov (United States)

Tuffner, Francis K [Richland, WA; Kintner-Meyer, Michael C. W. [Richland, WA; Hammerstrom, Donald J [West Richland, WA; Pratt, Richard M [Richland, WA

2012-05-22

Battery charging control methods, electric vehicle charging methods, battery charging apparatuses and rechargeable battery systems. According to one aspect, a battery charging control method includes accessing information regarding a presence of at least one of a surplus and a deficiency of electrical energy upon an electrical power distribution system at a plurality of different moments in time, and using the information, controlling an adjustment of an amount of the electrical energy provided from the electrical power distribution system to a rechargeable battery to charge the rechargeable battery.

Charge imbalance

International Nuclear Information System (INIS)

Clarke, J.

1981-01-01

This article provides a long theoretical development of the main ideas of charge imbalance in superconductors. Concepts of charge imbalance and quasiparticle charge are introduced, especially in regards to the use of tunnel injection in producing and detecting charge imbalance. Various mechanisms of charge relaxation are discussed, including inelastic scattering processes, elastic scattering in the presence of energy-gap anisotropy, and various pair-breaking mechanisms. In each case, present theories are reviewed in comparison with experimental data

Charged Hadron Multiplicity Distribution at Relativistic Heavy-Ion Colliders

Directory of Open Access Journals (Sweden)

Ashwini Kumar

2013-01-01

Full Text Available The present paper reviews facts and problems concerning charge hadron production in high energy collisions. Main emphasis is laid on the qualitative and quantitative description of general characteristics and properties observed for charged hadrons produced in such high energy collisions. Various features of available experimental data, for example, the variations of charged hadron multiplicity and pseudorapidity density with the mass number of colliding nuclei, center-of-mass energies, and the collision centrality obtained from heavy-ion collider experiments, are interpreted in the context of various theoretical concepts and their implications. Finally, several important scaling features observed in the measurements mainly at RHIC and LHC experiments are highlighted in the view of these models to draw some insight regarding the particle production mechanism in heavy-ion collisions.

Long-range interaction between heterogeneously charged membranes.

Science.gov (United States)

Jho, Y S; Brewster, R; Safran, S A; Pincus, P A

2011-04-19

Despite their neutrality, surfaces or membranes with equal amounts of positive and negative charge can exhibit long-range electrostatic interactions if the surface charge is heterogeneous; this can happen when the surface charges form finite-size domain structures. These domains can be formed in lipid membranes where the balance of the different ranges of strong but short-ranged hydrophobic interactions and longer-ranged electrostatic repulsion result in a finite, stable domain size. If the domain size is large enough, oppositely charged domains in two opposing surfaces or membranes can be strongly correlated by the electrostatic interactions; these correlations give rise to an attractive interaction of the two membranes or surfaces over separations on the order of the domain size. We use numerical simulations to demonstrate the existence of strong attractions at separations of tens of nanometers. Large line tensions result in larger domains but also increase the charge density within the domain. This promotes correlations and, as a result, increases the intermembrane attraction. On the other hand, increasing the salt concentration increases both the domain size and degree of domain anticorrelation, but the interactions are ultimately reduced due to increased screening. The result is a decrease in the net attraction as salt concentration is increased. © 2011 American Chemical Society

The Schottky energy barrier dependence of charge injection in organic light-emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Campbell, I.H.; Davids, P.S.; Smith, D.L. [Los Alamos National Laboratory, Los Alamos, New Mexico87545 (United States); Barashkov, N.N.; Ferraris, J.P. [The University of Texas at Dallas, Richardson, Texas75083 (United States)

1998-04-01

We present device model calculations of the current{endash}voltage (I{endash}V) characteristics of organic diodes and compare them with measurements of structures fabricated using MEH-PPV. The structures are designed so that all of the current is injected from one contact. The I{endash}V characteristics are considered as a function of the Schottky energy barrier to charge injection from the contact. Experimentally, the Schottky barrier is varied from essentially zero to more than 1 eV by using different metal contacts. A consistent description of the device I{endash}V characteristics is obtained as the Schottky barrier is varied from small values, less than about 0.4 eV, where the current flow is space-charge limited to larger values where it is contact limited. {copyright} {ital 1998 American Institute of Physics.}

Si/SiC heterojunction optically controlled transistor with charge compensation layer

Directory of Open Access Journals (Sweden)

Pu Hongbin

2016-01-01

Full Text Available A novel n-SiC/p-Si/n-Si optically controlled transistor with charge compensation layer has been studied in the paper. The performance of the device is simulated using Silvaco Atlas tools, which indicates excellent performances of the device in both blocking state and conducting state. The device also has a good switching characteristic with 0.54μs as rising time and 0.66μs as falling time. With the charge compensation layer, the breakdown voltage and the spectral response intensity of the device are improved by 90V and 33A/W respectively. Compared with optically controlled transistor without charge compensation layer, the n-SiC/p-Si/n-Si optically controlled transistor with charge compensation layer has a better performance.

Voltammetry for the charge transfer at two immiscible electrolyte solutions interface

International Nuclear Information System (INIS)

Kihara, S.; Suzuki, M.; Maeda, K.; Ogura, K.; Matsui, M.; Yoshida, Z.

1989-01-01

The voltammetry for the charge transfer (VCT) at the interface of immicible solutions is a very powerful method for understanding the dynamic features of the charge transfer because of its unmatched advantage that the transfer energy and the number of charges transferred can be measured simultaneously and in situ. In the present paper, several novel systems for electron transfer are outlined, and the following topics are discussed based on results obtained by the current scan polarography at the solution dropping electrode developed as a technique for VCT: the relation between the half-wave potential in VCT for ion transfer and the characteristics of the ion transferred; the relation between the half-wave potential in VCT for electron transfer and the electrochemical nature of a redox couple added in water and that added in organic solution; and the ion transfer through a liquid membrane promoted by electron transfer. Observations are presented and discussion is made on the characteristics of ion transfer polarograms, those of electron transfer polarograms, and ion transfer promoted by electron transfer at a liquid/membrane interface. (N.K.)

Distribution of a vacuum charge near supercharged nuclei

International Nuclear Information System (INIS)

Migdal, A.B.; Popov, V.S.; Voskresenskij, D.N.; Gosudarstvennyj Komitet po Ispol'zovaniyu Atomnoj Ehnergii SSSR, Moscow. Inst. Teoreticheskoj i Ehksperimental'noj Fiziki)

1977-01-01

The distribution of a vacuum charge near super-critical nuclei (Ze 2 > > 1) is found. The calculation is performed in the Thomas - Fermi approximation extended to the relativistic case. The characteristic parameter in the present problem is Ze 3 approximately Z/1600. For Ze 3 approximately 1 the total charge of the vacuum shell becomes comparable to the nuclear charge Z. The relativistic Thomas - Fermi equation for the vacuum shell of a supercritical atom is solved analytically for two extreme cases, Ze 3 3 > > 1. In the intermediate region, Ze 3 approximately 1, the equation is solved numerically. The Thomas - Fermi equation for a neutral atom (in which not only the vacuum but external electron shells as well are filled up) and also the equation in which allowance is made for exchange and correlation corrections (relativistic generalization of the Thomas -Fermi - Dirac equation) are also considered

Theory and application of dual-transistor charge separation analysis

International Nuclear Information System (INIS)

Fleetwood, D.M.; Schwank, J.R.; Winokur, P.S.; Sexton, F.W.; Shaneyfelt, M.R.

1989-01-01

The authors describe a dual-transistor charge separation method to evaluate the radiation response of MOS transistors. This method requires that n- and p-channel transistors with identically processed oxides be irradiated under identical conditions at the same oxide electric fields. Combining features of single-transistor midgap and mobility methods, the authors show how one may determine threshold voltage shifts due to oxide-trapped and interface-trapped charge from standard threshold voltage and mobility measurements. These measurements can be made at currents 2-5 orders of magnitude higher than those required for midgap, subthreshold slope, and charge-pumping methods. The dual-transistor method contains no adjustable parameters, and includes an internal self-consistency check. The accuracy of the method is verified by comparison to midgap, subthreshold slope, and charge-pumping methods for several MOS processes and technologies

Stability Dust-Ion-Acoustic Wave In Dusty Plasmas With Stream -Influence Of Charge Fluctuation Of Dust Grains

International Nuclear Information System (INIS)

Atamaniuk, Barbara; Zuchowski, Krzysztof

2006-01-01

There is a quickly increasing wealth of experimental data on so-called dusty plasmas i. e. ionized gases or usual plasmas that contain micron sized charged particles. Interest in these structures is driven both by their importance in many astrophysical as well as commercial situations. Among them are linear and nonlinear wave phenomena. We consider the influence of dust charge fluctuations on stability of the ion-acoustic waves when the stream of particles is present. It is assumed that all grains of dust have equal masses but charges are not constant in time-they may fluctuate in time. The dust charges are not really independent of the variations of the plasma potentials. All modes will influence the charging mechanism, and feedback will lead to several new interesting and unexpected phenomena. The charging of the grains depends on local plasma characteristics. If the waves disturb these characteristic, then charging of the grains is affected and the grain charge is modified, with a resulting feedback on the wave mode. In case considering here, when temperature of electrons is much greater then the temperature of the ions and temperature of electrons is not great enough for further ionization of the ions, we show that stability of the acoustic wave depends only one phenomenological coefficient

Solar Wind Charge Exchange During Geomagnetic Storms

Science.gov (United States)

Robertson, Ina P.; Cravens, Thomas E.; Sibeck, David G.; Collier, Michael R.; Kuntz, K. D.

2012-01-01

On March 31st. 2001, a coronal mass ejection pushed the subsolar magnetopause to the vicinity of geosynchronous orbit at 6.6 RE. The NASA/GSFC Community Coordinated Modeling Center (CCMe) employed a global magnetohydrodynamic (MHD) model to simulate the solar wind-magnetosphere interaction during the peak of this geomagnetic storm. Robertson et aL then modeled the expected 50ft X-ray emission due to solar wind charge exchange with geocoronal neutrals in the dayside cusp and magnetosheath. The locations of the bow shock, magnetopause and cusps were clearly evident in their simulations. Another geomagnetic storm took place on July 14, 2000 (Bastille Day). We again modeled X-ray emission due to solar wind charge exchange, but this time as observed from a moving spacecraft. This paper discusses the impact of spacecraft location on observed X-ray emission and the degree to which the locations of the bow shock and magnetopause can be detected in images.

Charge migration and charge transfer in molecular systems

Directory of Open Access Journals (Sweden)

Hans Jakob Wörner

2017-11-01

Full Text Available The transfer of charge at the molecular level plays a fundamental role in many areas of chemistry, physics, biology and materials science. Today, more than 60 years after the seminal work of R. A. Marcus, charge transfer is still a very active field of research. An important recent impetus comes from the ability to resolve ever faster temporal events, down to the attosecond time scale. Such a high temporal resolution now offers the possibility to unravel the most elementary quantum dynamics of both electrons and nuclei that participate in the complex process of charge transfer. This review covers recent research that addresses the following questions. Can we reconstruct the migration of charge across a molecule on the atomic length and electronic time scales? Can we use strong laser fields to control charge migration? Can we temporally resolve and understand intramolecular charge transfer in dissociative ionization of small molecules, in transition-metal complexes and in conjugated polymers? Can we tailor molecular systems towards specific charge-transfer processes? What are the time scales of the elementary steps of charge transfer in liquids and nanoparticles? Important new insights into each of these topics, obtained from state-of-the-art ultrafast spectroscopy and/or theoretical methods, are summarized in this review.

Scaling dependence of memory windows and different carrier charging behaviors in Si nanocrystal nonvolatile memory devices

Science.gov (United States)

Yu, Jie; Chen, Kun-ji; Ma, Zhong-yuan; Zhang, Xin-xin; Jiang, Xiao-fan; Wu, Yang-qing; Huang, Xin-fan; Oda, Shunri

2016-09-01

Based on the charge storage mode, it is important to investigate the scaling dependence of memory performance in silicon nanocrystal (Si-NC) nonvolatile memory (NVM) devices for its scaling down limit. In this work, we made eight kinds of test key cells with different gate widths and lengths by 0.13-μm node complementary metal oxide semiconductor (CMOS) technology. It is found that the memory windows of eight kinds of test key cells are almost the same of about 1.64 V @ ± 7 V/1 ms, which are independent of the gate area, but mainly determined by the average size (12 nm) and areal density (1.8 × 1011/cm2) of Si-NCs. The program/erase (P/E) speed characteristics are almost independent of gate widths and lengths. However, the erase speed is faster than the program speed of test key cells, which is due to the different charging behaviors between electrons and holes during the operation processes. Furthermore, the data retention characteristic is also independent of the gate area. Our findings are useful for further scaling down of Si-NC NVM devices to improve the performance and on-chip integration. Project supported by the State Key Development Program for Basic Research of China (Grant No. 2010CB934402) and the National Natural Science Foundation of China (Grant Nos. 11374153, 61571221, and 61071008).

Probabilistic Harmonic Calculation in Distribution Networks with Electric Vehicle Charging Stations

Directory of Open Access Journals (Sweden)

Jianxue Wang

2014-01-01

Full Text Available Integrating EV charging station into power grid will bring impacts on power system, among which the most significant one is the harmonic pollution on distribution networks. Due to the uncertainty of the EV charging process, the harmonic currents brought by EV charging stations have a random nature. This paper proposed a mathematical simulation method for studying the working status of charging stations, which considers influencing factors including random leaving factor, electricity price, and waiting time. Based on the proposed simulation method, the probability distribution of the harmonic currents of EV charging stations is obtained and used in the calculation of the probability harmonic power flow. Then the impacts of EVs and EV charging stations on distribution networks can be analyzed. In the case study, the proposed simulation and analysis method is implemented on the IEEE-34 distribution network. The influences of EV arrival rates, the penetration rate, and the accessing location of EV charging station are also investigated. Results show that this research has good potential in guiding the planning and construction of charging station.

Total source charge and charge screening in Yang-Mills theories

International Nuclear Information System (INIS)

Campbell, W.B.; Norton, R.E.

1991-01-01

New gauge-invariant definitions for the total charge on a static Yang-Mills source are suggested which we argue are better suited for determining when true color screening has occurred. In particular, these new definitions imply that the Abelian Coulomb solution for a simple ''electric'' dipole source made up of two opposite point charges has zero total source charge and therefore no color screening. With the definition of total source charge previously suggested by other authors, such a source would have a total source charge of 2q and therefore a screening charge in the field of -2q, where q is the magnitude of the charge of either point charge. Our definitions for more general solutions are not unique because of the path dependence of the parallel transport of charges. Suggestions for removing this ambiguity are offered, but it is not known if a unique, physically meaningful definition of total source charge in fact exists

Collisionless damping of dust-acoustic waves in a charge varying dusty plasma with nonextensive ions

Energy Technology Data Exchange (ETDEWEB)

Amour, Rabia; Tribeche, Mouloud [Faculty of Physics, Theoretical Physics Laboratory (TPL), Plasma Physics Group (PPG), University of Bab-Ezzouar, USTHB, B.P. 32, El Alia, Algiers 16111 (Algeria)

2014-12-15

The charge variation induced nonlinear dust-acoustic wave damping in a charge varying dusty plasma with nonextensive ions is considered. It is shown that the collisionless damping due to dust charge fluctuation causes the nonlinear dust acoustic wave propagation to be described by a damped Korteweg-de Vries (dK-dV) equation the coefficients of which depend sensitively on the nonextensive parameter q. The damping term, solely due to the dust charge variation, is affected by the ion nonextensivity. For the sake of completeness, the possible effects of nonextensivity and collisionless damping on weakly nonlinear wave packets described by the dK-dV equation are succinctly outlined by deriving a nonlinear Schrödinger-like equation with a complex nonlinear coefficient.

Collisionless damping of dust-acoustic waves in a charge varying dusty plasma with nonextensive ions

International Nuclear Information System (INIS)

Amour, Rabia; Tribeche, Mouloud

2014-01-01

The charge variation induced nonlinear dust-acoustic wave damping in a charge varying dusty plasma with nonextensive ions is considered. It is shown that the collisionless damping due to dust charge fluctuation causes the nonlinear dust acoustic wave propagation to be described by a damped Korteweg-de Vries (dK-dV) equation the coefficients of which depend sensitively on the nonextensive parameter q. The damping term, solely due to the dust charge variation, is affected by the ion nonextensivity. For the sake of completeness, the possible effects of nonextensivity and collisionless damping on weakly nonlinear wave packets described by the dK-dV equation are succinctly outlined by deriving a nonlinear Schrödinger-like equation with a complex nonlinear coefficient

Charge state distribution of ionic kryptons after photoionization

International Nuclear Information System (INIS)

Cai Xiaohong

1992-01-01

Monochromatic X-rays from the 2.3 GeV synchrotron at University Bonn (Germany) are employed for inner shell excitation of krypton. Various ionic kryptons and a number of electrons are produced due to photoionization. In order to study the equilibrium charge state distribution of ionic kryptons, a time of flight mass spectrometer is set up and used to measure the resulting ionic charge spectra with photo energies near the L 1 - , L 2 - and L 3 - absorption edges of krypton. The energy dependence of relative probabilities is presented

Workplace Charging. Charging Up University Campuses

Energy Technology Data Exchange (ETDEWEB)

Giles, Carrie [ICF International, Fairfax, VA (United States); Ryder, Carrie [ICF International, Fairfax, VA (United States); Lommele, Stephen [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-03-01

This case study features the experiences of university partners in the U.S. Department of Energy's (DOE) Workplace Charging Challenge with the installation and management of plug-in electric vehicle (PEV) charging stations.

Measurement and control of electrostatic charges on solids in a gaseous suspension

Science.gov (United States)

Nieh, S.; Nguyen, T.

1985-10-01

Measurements of mean particle charges and charge distributions on Medium Volatile Bituminous (MVB) coals and Lignite A (LIGA) coals in a 51 mm ID grounded copper pipe loop have been made with the upgraded Faraday cage system. Both negative and positive charges were found for coals in all experiments. The dual polarities of charges are believed to be due to the nonuniform materials and chemical composition contained in coals. As expected, increasing velocity or decreasing air humidity has a significant effect to increase the mean particle charge and the standard deviation of distribution. Charge elimination by the addition of coal fines has been explored. Effective suppression of particle charges was achieved by adding 0.1% by mass of minus 1 micron coal dust into the pipe flow. A neutralization mechanism was proposed to interpret the measured results. The results of charge control obtained to date has been significant and encouraging. More work is needed to validate the proposed mechanism.

Lateral charge transport from heavy-ion tracks in integrated circuit chips

Science.gov (United States)

Zoutendyk, J. A.; Schwartz, H. R.; Nevill, L. R.

1988-01-01

A 256K DRAM has been used to study the lateral transport of charge (electron-hole pairs) induced by direct ionization from heavy-ion tracks in an IC. The qualitative charge transport has been simulated using a two-dimensional numerical code in cylindrical coordinates. The experimental bit-map data clearly show the manifestation of lateral charge transport in the creation of adjacent multiple-bit errors from a single heavy-ion track. The heavy-ion data further demonstrate the occurrence of multiple-bit errors from single ion tracks with sufficient stopping power. The qualitative numerical simulation results suggest that electric-field-funnel-aided (drift) collection accounts for single error generated by an ion passing through a charge-collecting junction, while multiple errors from a single ion track are due to lateral diffusion of ion-generated charge.

Complexation of Polyelectrolyte Micelles with Oppositely Charged Linear Chains.

Science.gov (United States)

Kalogirou, Andreas; Gergidis, Leonidas N; Miliou, Kalliopi; Vlahos, Costas

2017-03-02

The formation of interpolyelectrolyte complexes (IPECs) from linear AB diblock copolymer precursor micelles and oppositely charged linear homopolymers is studied by means of molecular dynamics simulations. All beads of the linear polyelectrolyte (C) are charged with elementary quenched charge +1e, whereas in the diblock copolymer only the solvophilic (A) type beads have quenched charge -1e. For the same Bjerrum length, the ratio of positive to negative charges, Z +/- , of the mixture and the relative length of charged moieties r determine the size of IPECs. We found a nonmonotonic variation of the size of the IPECs with Z +/- . For small Z +/- values, the IPECs retain the size of the precursor micelle, whereas at larger Z +/- values the IPECs decrease in size due to the contraction of the corona and then increase as the aggregation number of the micelle increases. The minimum size of the IPECs is obtained at lower Z +/- values when the length of the hydrophilic block of the linear diblock copolymer decreases. The aforementioned findings are in agreement with experimental results. At a smaller Bjerrum length, we obtain the same trends but at even smaller Z +/- values. The linear homopolymer charged units are distributed throughout the corona.

Electronic Transport Behaviors due to Charge Density Waves in Ni-Nb-Zr-H Glassy Alloys

Science.gov (United States)

Fukuhara, Mikio; Umemori, Yoshimasa

2013-11-01

The amorphous Ni-Nb-Zr-H glassy alloy containing subnanometer-sized icosahedral Zr5 Nb5Ni3 clusters exhibited four types of electronic phenomena: a metal/insulator transition, an electric current-induced voltage oscillation (Coulomb oscillation), giant capacitor behavior and an electron avalanche with superior resistivity. These findings could be excluded by charge density waves that the low-dimensional component of clusters, in which the atoms are lined up in chains along the [130] direction, plays important roles in various electron transport phenomena.

Bibliography of integral charged-particle nuclear data

International Nuclear Information System (INIS)

Burrows, T.W.; Wyant, G.

1981-03-01

This publication is the first supplement to the archival edition of the National Nuclear Data Center's charged-particle bibliography. This supplement contains citations to all references scanned since March 15, 1980, and all corrections and additions to previous citations, and indexes all data received in the international exchanged format (EXFOR). The primary goal of the bibliography has been to satisfy the need expressed by the Nuclear Reaction Data Center Network for a concise and comprehensive bibliography of integral charged-particle cross section data and to provide an index of data exchanged among the members. As a result of a recommendation by the recent Workshop on Intense High Energy Neutron Source and Their Characteristics, we have also undertaken to expand the coverage of charged-particle-induced neutron-source reactions to include differential data. This supplement is divided into two sections, References and Isotope Production. The References section contains all references satisfying the criteria noted. The Isotope Production section contains an abbreviated reference line for all entries which contain information on a definite residual nucleus, on particle production, or on mass, charge, or isotopic distributions. Entries in the References section are sequentially numbered. These sequence numbers serve as a link between the two sections

Charge exchange cooling in the tandem mirror plasma confinement apparatus

International Nuclear Information System (INIS)

Logan, B.G.

1978-01-01

A method and apparatus are described for cooling a plasma confined in the center mirror cell of the tandem mirror apparatus by injecting cold neutral species of the plasma into at least one mirroring region of the center mirror cell. The cooling is due to the loss of warm charged species through charge exchange with the cold neutral species with resulting diffusion of the warm neutral species out of the plasma

Parsimonious Charge Deconvolution for Native Mass Spectrometry

Science.gov (United States)

2018-01-01

Charge deconvolution infers the mass from mass over charge (m/z) measurements in electrospray ionization mass spectra. When applied over a wide input m/z or broad target mass range, charge-deconvolution algorithms can produce artifacts, such as false masses at one-half or one-third of the correct mass. Indeed, a maximum entropy term in the objective function of MaxEnt, the most commonly used charge deconvolution algorithm, favors a deconvolved spectrum with many peaks over one with fewer peaks. Here we describe a new “parsimonious” charge deconvolution algorithm that produces fewer artifacts. The algorithm is especially well-suited to high-resolution native mass spectrometry of intact glycoproteins and protein complexes. Deconvolution of native mass spectra poses special challenges due to salt and small molecule adducts, multimers, wide mass ranges, and fewer and lower charge states. We demonstrate the performance of the new deconvolution algorithm on a range of samples. On the heavily glycosylated plasma properdin glycoprotein, the new algorithm could deconvolve monomer and dimer simultaneously and, when focused on the m/z range of the monomer, gave accurate and interpretable masses for glycoforms that had previously been analyzed manually using m/z peaks rather than deconvolved masses. On therapeutic antibodies, the new algorithm facilitated the analysis of extensions, truncations, and Fab glycosylation. The algorithm facilitates the use of native mass spectrometry for the qualitative and quantitative analysis of protein and protein assemblies. PMID:29376659

Charge trapping of Ge-nanocrystals embedded in TaZrOx dielectric films

International Nuclear Information System (INIS)

Lehninger, D.; Seidel, P.; Geyer, M.; Schneider, F.; Heitmann, J.; Klemm, V.; Rafaja, D.; Borany, J. von

2015-01-01

Ge-nanocrystals (NCs) were synthesized in amorphous TaZrO x by thermal annealing of co-sputtered Ge-TaZrO x layers. Formation of spherical shaped Ge-NCs with small variation of size, areal density, and depth distribution was confirmed by high-resolution transmission electron microscopy. The charge storage characteristics of the Ge-NCs were investigated by capacitance-voltage and constant-capacity measurements using metal-insulator-semiconductor structures. Samples with Ge-NCs exhibit a maximum memory window of 5 V by sweeping the bias voltage from −7 V to 7 V and back. Below this maximum, the width of the memory window can be controlled by the bias voltage. The fitted slope of the memory window versus bias voltage characteristics is very close to 1 for samples with one layer Ge-NCs. A second layer Ge-NCs does not result in a second flat stair in the memory window characteristics. Constant-capacity measurements indicate charge storage in trapping centers at the interfaces between the Ge-NCs and the surrounding materials (amorphous matrix/tunneling oxide). Charge loss occurs by thermal detrapping and subsequent band-to-band tunneling. Reference samples without Ge-NCs do not show any memory window

μe conversion experiments. Testing charged lepton flavor violation

International Nuclear Information System (INIS)

Schaaf, Andries van der

2004-01-01

The recent evidence for neutrino mixing shows that lepton flavor is not a conserved quantity. Due to the smallness of the neutrino masses effective flavor changing neutral currents among charged leptons remain negligible in the Standard Model. Whereas b → sγ has a probability of O(10 -4 )μ → eγ is expected with a branching ratio around 10 -50 . Observable rates would be an unambiguous signal for physics beyond the Standard Model and indeed, many extensions of the model are constrained best by the present experimental limits on charged lepton flavor violation. In this talk I will discuss experimental searches for charged lepton flavor violation with emphasis on μe conversion in muonic atoms. (author)

Electrostatic sensors applied to the measurement of electric charge transfer in gas-solids pipelines

International Nuclear Information System (INIS)

Woodhead, S R; Denham, J C; Armour-Chelu, D I

2005-01-01

This paper describes the development of a number of electric charge sensors. The sensors have been developed specifically to investigate triboelectric charge transfer which takes place between particles and the pipeline wall, when powdered materials are conveyed through a pipeline using air. A number of industrial applications exist for such gas-solids pipelines, including pneumatic conveyors, vacuum cleaners and dust extraction systems. The build-up of electric charge on pipelines and powdered materials can lead to electrostatic discharge and so is of interest from a safety viewpoint. The charging of powders can also adversely affect their mechanical handling characteristics and so is of interest to handling equipment engineers. The paper presents the design of the sensors, the design of the electric charge test rig and electric charge measurement test results

Charged rotating black holes on a 3-brane

International Nuclear Information System (INIS)

Aliev, A.N.; Guemruekcueoglu, A.E.

2005-01-01

We study exact stationary and axisymmetric solutions describing charged rotating black holes localized on a 3-brane in the Randall-Sundrum braneworld. The charges of the black holes are considered to be of two types, the first being an induced tidal charge that appears as an imprint of nonlocal gravitational effects from the bulk space and the second is a usual electric charge arising due to a Maxwell field trapped on the brane. We assume a special ansatz for the metric on the brane taking it to be of the Kerr-Schild form and show that the Kerr-Newman solution of ordinary general relativity in which the electric charge is superseded by a tidal charge satisfies a closed system of the effective gravitational field equations on the brane. It turns out that the negative tidal charge may provide a mechanism for spinning up the black hole so that its rotation parameter exceeds its mass. This is not allowed in the framework of general relativity. We also find a new solution that represents a rotating black hole on the brane carrying both charges. We show that for a rapid enough rotation the combined influence of the rotational dynamics and the local bulk effects of the 'squared' energy-momentum tensor on the brane distort the horizon structure of the black hole in such a way that it can be thought of as composed of nonuniformly rotating null circles with growing radii from the equatorial plane to the poles. We finally study the geodesic motion of test particles in the equatorial plane of a rotating black hole with tidal charge. We show that the effects of negative tidal charge tend to increase the horizon radius, as well as the radii of the limiting photon orbit, the innermost bound and the innermost stable circular orbits for both direct and retrograde motions of the particles

Space charge and magnet error simulations for the SNS accumulator ring

International Nuclear Information System (INIS)

Beebe-Wang, J.; Fedotov, A.V.; Wei, J.; Machida, S.

2000-01-01

The effects of space charge forces and magnet errors in the beam of the Spallation Neutron Source (SNS) accumulator ring are investigated. In this paper, the focus is on the emittance growth and halo/tail formation in the beam due to space charge with and without magnet errors. The beam properties of different particle distributions resulting from various injection painting schemes are investigated. Different working points in the design of SNS accumulator ring lattice are compared. The simulations in close-to-resonance condition in the presence of space charge and magnet errors are presented. (author)

A row-charge nuclear cratering explosion in alluvial rocks

International Nuclear Information System (INIS)

Kireev, V.V.; Kedrovskij, O.L.; Valentinov, Yu.A.; Myasnikov, K.V.; Nikiforov, G.A.; Prozorov, L.B.; Potapov, V.K.

1975-01-01

A brief description is given of the first row-charge nuclear cratering explosion in alluvial rocks carried out on the route of the Pechora-Kolva canal. The authors explain the purposes of the explosion, describe the geological conditions, indicate the emplacement parameters and yields of the charges, present data on the dynamics of development of the explosion and report on its seismic effects. The parameters of the resulting trench cut and the characteristics of the rock ejecta are also given. The possibility of using nuclear explosions for hydrotechnological projects requiring large excavations in a thick stratum of weak water-bearing rocks is considered

Integration Assessment of Visiting Vehicle Induced Electrical Charging of the International Space Station Structure

Science.gov (United States)

Kramer, Leonard; Kerslake, Thomas W.; Galofaro, Joel T.

2010-01-01

The International Space Station (ISS) undergoes electrical charging in low Earth orbit (LEO) due to positively biased, exposed conductors on solar arrays that collect electrical charges from the space plasma. Exposed solar array conductors predominately collect negatively charged electrons and thus drive the metal ISS structure electrical ground to a negative floating potential (FP) relative to plasma. This FP is variable in location and time as a result of local ionospheric conditions. ISS motion through Earth s magnetic field creates an addition inductive voltage up to 20 positive and negative volts across ISS structure depending on its attitude and location in orbit. ISS Visiting Vehicles (VVs), such as the planned Orion crew exploration vehicle, contribute to the ISS plasma charging processes. Upon physical contact with ISS, the current collection properties of VVs combine with ISS. This is an ISS integration concern as FP must be controlled to minimize arcing of ISS surfaces and ensure proper management of extra vehicular activity crewman shock hazards. This report is an assessment of ISS induced charging from docked Orion vehicles employing negatively grounded, 130 volt class, UltraFlex (ATK Space Systems) solar arrays. To assess plasma electron current collection characteristics, Orion solar cell test coupons were constructed and subjected to plasma chamber current collection measurements. During these tests, coupon solar cells were biased between 0 and 120 V while immersed in a simulated LEO plasma. Tests were performed using several different simulated LEO plasma densities and temperatures. These data and associated theoretical scaling of plasma properties, were combined in a numerical model which was integrated into the Boeing Plasma Interaction Model. It was found that the solar array design for Orion will not affect the ISS FP by more than about 2 V during worst case charging conditions. This assessment also motivated a trade study to determine

Switchless charge-discharge circuit for electrical capacitance tomography

International Nuclear Information System (INIS)

Kryszyn, J; Smolik, W T; Radzik, B; Olszewski, T; Szabatin, R

2014-01-01

The main factor limiting the performance of electrical capacitance tomography (ECT) is an extremely low value of inter-electrode capacitances. The charge-discharge circuit is a well suited circuit for a small capacitance measurement due to its immunity to noise and stray capacitance, although it has a problem associated with a charge injected by the analogue switches, which results in a dc offset. This paper presents a new diode-based circuit for capacitance measurement in which a charge transfer method is realized without switches. The circuit was built and tested in one channel configuration with 16 multiplexed electrodes. The performance of the elaborated circuit and a comparison with a classic charge-discharge circuit are presented. The elaborated circuit can be used for sensors with inter-electrode capacitances not lower than 10 fF. The presented approach allows us to obtain a similar performance to the classic charge-discharge circuit, but has a simplified design. A lack of the need to synchronize the analogue switches in the transmitter and the receiver part of this circuit could be a desirable feature in the design of measurement systems integrated with electrodes. (paper)

Landau damping due to tune spreads in betatron amplitude and momentum

International Nuclear Information System (INIS)

Lee, S.Y.; Tran, P.; Weng, W.T.

1989-01-01

Due to the large space charge transverse impedance in a low energy synchrotron, the coherent tune shift causes the Landau damping to be ineffective in damping the transverse coherent motion. We analyze the effect of Landau damping that is caused by the tune spreads of the betatron amplitude (space charge and/or octupole) and momentum. We find that the Landau damping becomes more significant in our two dimensional analysis. 5 refs

Charge independence and charge symmetry

Energy Technology Data Exchange (ETDEWEB)

Miller, G A [Washington Univ., Seattle, WA (United States). Dept. of Physics; van Oers, W T.H. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Physics; [TRIUMF, Vancouver, BC (Canada)

1994-09-01

Charge independence and charge symmetry are approximate symmetries of nature, violated by the perturbing effects of the mass difference between up and down quarks and by electromagnetic interactions. The observations of the symmetry breaking effects in nuclear and particle physics and the implications of those effects are reviewed. (author). 145 refs., 3 tabs., 11 figs.

Charge independence and charge symmetry

International Nuclear Information System (INIS)

Miller, G.A.

1994-09-01

Charge independence and charge symmetry are approximate symmetries of nature, violated by the perturbing effects of the mass difference between up and down quarks and by electromagnetic interactions. The observations of the symmetry breaking effects in nuclear and particle physics and the implications of those effects are reviewed. (author). 145 refs., 3 tabs., 11 figs

The role of water content in triboelectric charging of wind-blown sand.

Science.gov (United States)

Gu, Zhaolin; Wei, Wei; Su, Junwei; Yu, Chuck Wah

2013-01-01

Triboelectric charging is common in desert sandstorms and dust devils on Earth; however, it remains poorly understood. Here we show a charging mechanism of sands with the adsorbed water on micro-porous surface in wind-blown sand based on the fact that water content is universal but usually a minor component in most particle systems. The triboelectric charging could be resulted due to the different mobility of H(+)/OH(-) between the contacting sands with a temperature difference. Computational fluid dynamics (CFD) and discrete element method (DEM) were used to demonstrate the dynamics of the sand charging. The numerically simulated charge-to-mass ratios of sands and electric field strength established in wind tunnel agreed well with the experimental data. The charging mechanism could provide an explanation for the charging process of all identical granular systems with water content, including Martian dust devils, wind-blown snow, even powder electrification in industrial processes.

Characterization of surface charge and mechanical properties of chitosan/alginate based biomaterials

International Nuclear Information System (INIS)

Verma, Devendra; Desai, Malav S.; Kulkarni, Namrata; Langrana, Noshir

2011-01-01

This study aims to examine mechanical properties and surface charge characteristics of chitosan/alginate-based films for biomedical applications. By varying the concentrations of chitosan and alginate, we have developed films with varying surface charge densities and mechanical characteristics. The surface charge densities of these films were determined by applying an analytical model on force curves derived from an atomic force microscope (AFM). The average surface charge densities of films containing 60% chitosan and 80% chitosan were found to be - 0.46 mC/m 2 and - 0.32 mC/m 2 , respectively. The surface charge density of 90% chitosan containing films was found to be neutral. The elastic moduli and the water content were found to be decreasing with increasing chitosan concentration. The films with 60%, 80% and 90% chitosan gained 93.5 ± 6.6%, 217.1 ± 22.1% and 396.8 ± 67.5% of their initial weight, respectively. Their elastic moduli were found to be 2.6 ± 0.14 MPa, 1.9 ± 0.27 MPa and 0.93 ± 0.12 MPa, respectively. The trend observed in the mechanical response of these films has been attributed to the combined effect of the concentration of polyelectrolyte complexes (PEC) and the amount of water absorbed. The Fourier transform infrared spectroscopy experiments indicate the presence of higher alginate on the surface of the films compared to the bulk in all films. The presence of higher alginate on surface is consistent with negative surface charge densities of these films, determined from AFM experiments. Highlights: → Chitosan/alginate based fibrous polyelectrolyte complex films were developed. → The average surface charge density of the films was determined using AFM. → Elastic modulus of the films increased with increase in PEC content. → FTIR analysis indicated higher alginate content on surface compared to bulk.

Multifunctional hybrid diode: Study of photoresponse, high responsivity, and charge injection mechanisms

Science.gov (United States)

Singh, Jitendra; Singh, R. G.; Gautam, Subodh K.; Singh, Fouran

2018-05-01

A multifunctional hybrid heterojunction diode is developed on porous silicon and its current density-voltage characteristics reveal a good rectification ratio along with other superior parameters such as ideality factor, barrier height and series resistance. The diode also functions as an efficient photodiode to manifest high photosensitivity with high responsivity under illumination with broadband solar light, UV light, and green light. The diode is also carefully scrutinized for its sensitivity and repeatability over many cycles under UV and green light and is found to have a quick response and extremely fast recovery times. The notable responsivity is attributed to the generation of high density of excitons in the depletion region by the absorption of incident photons and their separation by an internal electric field besides an additional photocurrent due to the charging of polymer chains. The mechanisms of generation, injection and transport of charge carriers are explained by developing a schematic energy band diagram. The transport phenomenon of carriers is further investigated from room temperature down to a very low temperature of 10 K. An Arrhenius plot is made to determine the Richardson constant. Various diode parameters as mentioned above are also determined and the dominance of the transport mechanism of charge carriers in different temperature regimes such as diffusion across the junction and/or quantum tunneling through the barriers are explained. The developed multifunction heterojunction hybrid diodes have implications for highly sensitive photodiodes in the UV and visible range of electromagnetic spectrum that can be very promising for efficient optoelectronic devices.

Role of stochastic fluctuations in the charge on macroscopic particles in dusty plasmas

International Nuclear Information System (INIS)

Vaulina, O.S.; Nefedov, A.P.; Petrov, O.F.; Khrapak, S.A.

1999-01-01

The currents which charge a macroscopic particle placed in a plasma consist of discrete charges; hence, the charge can undergo random fluctuations about its equilibrium value. These random fluctuations can be described by a simple model which, if the mechanisms for charging of macroscopic particles are known, makes it possible to determine the dependence of the temporal and amplitude characteristics of the fluctuations on the plasma parameters. This model can be used to study the effect of charge fluctuations on the dynamics of the macroscopic particles. The case of so-called plasma-dust crystals (i.e., highly ordered structures which develop because of strong interactions among macroscopic particles) in laboratory gaseous discharge plasmas is considered as an example. The molecular dynamics method shows that, under certain conditions, random fluctuations in the charge can effectively heat a system of macroscopic particles, thereby impeding the ordering process