Sample records for effective charges application

  1. Stability of Positively Charged Nanoemulsion Formulation Containing Steroidal Drug for Effective Transdermal Application

    Directory of Open Access Journals (Sweden)

    Stephanie Da Costa


    Full Text Available This paper emphasizes the formation of a positively charged nanoemulsion system for steroid drugs (hydrocortisone. It is believed that positively charged nanoemulsion provides more effective penetration of the skin. Therefore in our study we focused on the incorporation of phytosphingosine which serves as a positively charged cosurfactant in the nanoemulsion system. Negatively charged nanoemulsions were formulated mainly for comparison. Freshly prepared formulations were formed with particle size less than 300 nm and showed good stability over time. The oil-in-water nanoemulsion also showed good viscosity, conductivity, and pH values. From TEM micrograph, particle size showed consistent results with the measurement using photon correlation spectroscopy. It was concluded that both positively and negatively charged nanoemulsions showed good stability and have great potential in transdermal delivery system. Though, further investigation of the drug release and drug penetration of both positively and negatively charged nanoemulsions will be studied to further prove the efficacy of nanoemulsion with hydrocortisone as a delivery system for dermal application.

  2. Stability of Positively Charged Nanoemulsion Formulation Containing Steroidal Drug for Effective Transdermal Application


    Stephanie Da Costa; Mahiran Basri; Norashikin Shamsudin; Hamidon Basri


    This paper emphasizes the formation of a positively charged nanoemulsion system for steroid drugs (hydrocortisone). It is believed that positively charged nanoemulsion provides more effective penetration of the skin. Therefore in our study we focused on the incorporation of phytosphingosine which serves as a positively charged cosurfactant in the nanoemulsion system. Negatively charged nanoemulsions were formulated mainly for comparison. Freshly prepared formulations were formed with particle...

  3. Space Charge Effects

    CERN Document Server

    Ferrario, M.; Palumbo, L.


    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.

  4. Space-Charge Effect

    CERN Document Server

    Chauvin, N.


    First, this chapter introduces the expressions for the electric and magnetic space-charge internal fields and forces induced by high-intensity beams. Then, the root-mean-square equation with space charge is derived and discussed. In the third section, the one-dimensional Child-Langmuir law, which gives the maximum current density that can be extracted from an ion source, is exposed. Space-charge compensation can occur in the low-energy beam transport lines (located after the ion source). This phenomenon, which counteracts the spacecharge defocusing effect, is explained and its main parameters are presented. The fifth section presents an overview of the principal methods to perform beam dynamics numerical simulations. An example of a particles-in-cells code, SolMaxP, which takes into account space-charge compensation, is given. Finally, beam dynamics simulation results obtained with this code in the case of the IFMIF injector are presented.

  5. Application and promotion of wireless charging technology


    Yan, Kaijun


    The aim of this thesis is to study wireless charging technology and analyze the application and promotion of each technology. This technology is based on Faraday’s electromagnetic in 1830s. It is not a new technology but it is developing high speed nowadays. This thesis introduces four mainstream types of wireless charging technology and three main-stream standards, and analyzes their features and development status. Wireless charging technology has been applied to some products, suc...

  6. Characterization of a glass GEM for sealed detectors application and reduction of charging-up effects

    CERN Document Server

    Erdal, Eran


    Apart from high energy physics experiments, there has been a great effort in recent years to incorporate MPGDs in many other applications i.e. medical treatments and imaging and home land security. However, MPGDs (as most gaseous detectors) are normally operated under a constant flushing of the gas. Their use thus turns them expensive since they rely on a constant gas supply and a suitable infrastructure, but most important is the loss of their portability. These reasons have pushed the community to search for other solutions, aiming for the development of sealed detectors. The demands for such is to be made out of low outgassing rate materials and possibly the use of only noble gas to avoid aging due to chemical activity of the ionized gas of the avalanche. The default material for GEM detectors - Polyimide (Kapton), is not suitable for a sealed detector because of its high outgassing rate, thus calling for new solutions. Moreover, GEMs, being essentially made out of an insulating material, pose a problem in...

  7. Modeling charge transport in C{sub 60}-based self-assembled monolayers for applications in field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Leitherer, S., E-mail:, E-mail:; Thoss, M., E-mail:, E-mail: [Institute for Theoretical Physics and Interdisciplinary Center for Molecular Materials, University Erlangen-Nürnberg, Staudtstr. 7/B2, D-91058 Erlangen (Germany); Jäger, C. M.; Clark, T. [Computer-Chemie-Centrum and Interdisciplinary Center for Molecular Materials, University Erlangen-Nürnberg, Nägelsbachstr. 25, 91052 Erlangen (Germany); Halik, M. [Organic Materials and Devices, Institute of Polymer Materials, Department of Materials Science, University Erlangen-Nürnberg, Martensstr. 7, D-91058 Erlangen (Germany)


    We have investigated the conductance properties of C{sub 60}-containing self-assembled monolayers (SAMs), which are used in organic field-effect transistors, employing a combination of molecular-dynamics simulations, semiempirical electronic structure calculations, and Landauer transport theory. The results reveal the close relation between the transport characteristics and the structural and electronic properties of the SAM. Furthermore, both local pathways of charge transport in the SAMs and the influence of structural fluctuations are analyzed.

  8. Fractional Effective Charges and Misner-Wheeler Charge without Charge Effect in Metamaterials

    Directory of Open Access Journals (Sweden)

    Igor Smolyaninov


    Full Text Available Transformation optics enables engineering of the effective topology and dimensionality of the optical space in metamaterials. Nonlinear optics of such metamaterials may mimic Kaluza-Klein theories having one or more kinds of effective charges. As a result, novel photon blockade devices may be realized. Here we demonstrate that an electromagnetic wormhole may be designed, which connects two points of such an optical space and changes its effective topological connectivity. Electromagnetic field configurations, which exhibit fractional effective charges, appear as a result of such topology change. Moreover, such effects as Misner-Wheeler “charge without charge” may be replicated.

  9. Sound propagation in narrow tubes including effects of viscothermal and turbulent damping with application to charge air coolers (United States)

    Knutsson, Magnus; Åbom, Mats


    Charge air coolers (CACs) are used on turbocharged internal combustion engines to enhance the overall gas-exchange performance. The cooling of the charged air results in higher density and thus volumetric efficiency. It is also important for petrol engines that the knock margin increases with reduced charge air temperature. A property that is still not very well investigated is the sound transmission through a CAC. The losses, due to viscous and thermal boundary layers as well as turbulence, in the narrow cooling tubes result in frequency dependent attenuation of the transmitted sound that is significant and dependent on the flow conditions. Normally, the cross-sections of the cooling tubes are neither circular nor rectangular, which is why no analytical solution accounting for a superimposed mean flow exists. The cross-dimensions of the connecting tanks, located on each side of the cooling tubes, are large compared to the diameters of the inlet and outlet ducts. Three-dimensional effects will therefore be important at frequencies significantly lower than the cut-on frequencies of the inlet/outlet ducts. In this study the two-dimensional finite element solution scheme for sound propagation in narrow tubes, including the effect of viscous and thermal boundary layers, originally derived by Astley and Cummings [Wave propagation in catalytic converters: Formulation of the problem and finite element scheme, Journal of Sound and Vibration 188 (5) (1995) 635-657] is used to extract two-ports to represent the cooling tubes. The approximate solutions for sound propagation, accounting for viscothermal and turbulent boundary layers derived by Dokumaci [Sound transmission in narrow pipes with superimposed uniform mean flow and acoustic modelling of automobile catalytic converters, Journal of Sound and Vibration 182 (5) (1995) 799-808] and Howe [The damping of sound by wall turbulent shear layers, Journal of the Acoustical Society of America 98 (3) (1995) 1723-1730], are

  10. Study on high breakdown voltage GaN-based vertical field effect transistor with interfacial charge engineering for power applications (United States)

    Du, Jiangfeng; Liu, Dong; Liu, Yong; Bai, Zhiyuan; Jiang, Zhiguang; Liu, Yang; Yu, Qi


    A high voltage GaN-based vertical field effect transistor with interfacial charge engineering (GaN ICE-VFET) is proposed and its breakdown mechanism is presented. This vertical FET features oxide trenches which show a fixed negative charge at the oxide/GaN interface. In the off-state, firstly, the trench oxide layer acts as a field plate; secondly, the n-GaN buffer layer is inverted along the oxide/GaN interface and thus a vertical hole layer is formed, which acts as a virtual p-pillar and laterally depletes the n-buffer pillar. Both of them modulate electric field distribution in the device and significantly increase the breakdown voltage (BV). Compared with a conventional GaN vertical FET, the BV of GaN ICE-VFET is increased from 1148 V to 4153 V with the same buffer thickness of 20 μm. Furthermore, the proposed device achieves a great improvement in the tradeoff between BV and on-resistance; and its figure of merit even exceeds the GaN one-dimensional limit.

  11. Charge Pump Circuits for Low-voltage Applications

    Directory of Open Access Journals (Sweden)

    Y. Moisiadis


    Full Text Available In this paper, a low-voltage, high performance charge pump circuit, suitable for implementation in standard CMOS technologies is proposed. Its pumping operation is based on cascading several cross-connected NMOS voltage doubler stages. For very low-voltage applications (1.2 V, 0.9 V, where the performance of the NMOS transistors is limited due to body effect, two improved versions of the charge pump with cascaded voltage doublers (charge pump with CVD are also proposed. The first utilises PMOS transistors (charge pump with CVD-PMOS in parallel to the cross-connected NMOS transistors, while the second improves the pumping gain by boosting the clock amplitude (charge pump with CVD-BCLK. Simulations at 50 MHz have shown that a five-stages charge pump with CVD can achieve a 1.5–8.4 V voltage conversion. For the same stage number and frequency, an output voltage of 4 and 7.3 V can be generated from 0.9 V, by using the charge pump with CVD-PMOS and the charge pump with CVD-BCLK, respectively.

  12. Ion space-charge effects in multi-GEM detectors: challenges and possible solutions for future applications

    CERN Document Server

    AUTHOR|(CDS)2079251; Streli, Christina

    Gaseous Electron Multiplier (GEM) detectors are well known both for stable operation under irradiation with high particle fluxes and high achievable effective gains. The aim of this thesis is two-fold: to investigate the limits of GEM detector operation due to space-charge effects, and to develop a means to reduce the magnitude of the observed effects and thus extend those limitations. The first part of the thesis presents a comprehensive study of the intrinsic limits of triple-GEM detectors under exposure to very high fluxes of soft X-rays or operation at very large effective gains. The behaviour of the effective gain, ion back-flow and the pulse-height spectra is explained in terms of the movement and accumulation of positive ions throughout the detector volume, resulting in distortions of the transfer and amplification fields. Numerical computations, and measurements on double-stage and single-stage detectors confirm the model describing the observed effects. Discussions on ways to extend the limits of gas...

  13. Application of channeling in bent crystals to charged particle beams

    Energy Technology Data Exchange (ETDEWEB)

    Carrigan, Jr., Richard A. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)


    The process of channeling of charged particle beams in bent crystals is described, including the effects of angular acceptance, spatial acceptance, normal dechanneling, bending dechanneling, and surface acceptance. Some bending applications that have been tried and future possibilities are reviewed. 29 refs., 30 figs. (LEW)

  14. The Shaped Charge Concept. Part 3. Applications of Shaped Charges (United States)


    perforating charges. Well perforator cones usually have an apex angle of 450 to About 600. The smaller angle increases penetation , but the hole size is...hole digging and underwaterdemlition via shaped charles . Byei (1949.1950) picacuw novel shaped chare designs for mining, hole drilling, and boulde

  15. Phase behavior of charged colloids : many-body effects, charge renormalization and charge regulation

    NARCIS (Netherlands)

    Zoetekouw, Bastiaan


    The main topic of this thesis is Poisson–Boltzmann theory for suspensions of charged colloids in two of its approximations: cell-type approximations that explicitly take into account non-linear effects near the colloidal surfaces, such as charge renormalization, at the expense of neglecting any

  16. Introduction to Space Charge Effects in Semiconductors

    CERN Document Server

    Böer, Karl W


    This book is the most comprehensive one to describe the basics of space-charge effects in semiconductors, starting from basic principles to advanced application in semiconducting devices. It uses detailed analyses of the transport, Poisson, and continuity equations to demonstrate the behavior of the solution curves of the complete set of field and current distributions, along with quantitative descriptions of the relevant band models of typical pn-junction and Schottky barrier devices. It emphasizes the relevance to actual devices and sets these results apart from more simple models of networks of diodes and resistors. The book is especially important for people interested in detail analysis of solar cells and their efficiencies.

  17. Applications of electrostatic capacitance and charging (United States)

    Sandu, Titus; Boldeiu, George; Moagar-Poladian, Victor


    The capacitance of an arbitrarily shaped object is calculated with the same second-kind integral equation method used for computing static and dynamic polarizabilities. The capacitance is simply the dielectric permittivity multiplied by the area of the object and divided by the squared norm of the Neumann-Poincaré operator eigenfunction corresponding to the largest eigenvalue. The norm of this eigenfunction varies slowly with shape thus enabling the definition of two scale-invariant shape factors and perturbative calculations of capacitance. The result is extended to a special class of capacitors in which the electrodes are the equipotential surfaces generated by the equilibrium charge on the object. This extension allows analytical expressions of capacitance for confocal spheroidal capacitors and finite cylinders. Moreover, a second order formula for thin constant-thickness capacitors is given with direct applications for capacitance of membranes in living cells and of supercapacitors. For axisymmetric geometries, a fast and accurate numerical method is provided.

  18. Alkaline peroxide treatment of ECF bleached softwood kraft pulps: part 2. effect of increased fiber charge on refining, wet-end application, and hornification (United States)

    Zheng Dang; Thomas Elder; Jeffery S. Hsieh; Arthur J. Ragauskas


    The effect of increased fiber charge on refining, cationic starch adsorption, and hornification was examined. Two pulps were investigated: (1) a softwood (SW) kraft pulp (KP) which was bleached elementally chlorine-free (ECF) and sewed as control; and (2) a control pulp treated with alkaline peroxide, which had a higher fiber charge. It was shown that increased fiber...

  19. Surface charge measurement by the Pockels effect

    CERN Document Server

    Sam, Y L


    have been observed by applying both impulse and AC voltages to a needle electrode in direct contact with the BSO. AC surface discharge behaviour of polymeric materials bonded to the BSO has also been investigated. The effect of the surrounding environment has been experimentally examined by placing the cell inside a vacuum chamber. Surface charge measurements have been made at various atmospheric pressures. The effect of an electro-negative gas (Sulphur Hexafluoride) on the surface charge distribution has also been investigated. This thesis is concerned with the design and development of a surface charge measurement system using Pockels effect. The measurement of surface charge is important in determining the electrical performance of high voltage insulation materials. The method proposed allows on-line measurement of charge and can generate two-dimensional images that represent the charge behaviour on the surface of the material under test. The measurement system is optical and uses a Pockels crystal as the ...

  20. Effect of Charge Patterning on the Phase Behavior of Polymer Coacervates for Charge Driven Self Assembly (United States)

    Radhakrishna, Mithun; Sing, Charles E.

    Oppositely charged polymers can undergo associative liquid-liquid phase separation when mixed under suitable conditions of ionic strength, temperature and pH to form what are known as `polymeric complex coacervates'. Polymer coacervates find use in diverse array of applications like microencapsulation, drug delivery, membrane filtration and underwater adhesives. The similarity between complex coacervate environments and those in biological systems has also found relevance in areas of bio-mimicry. Our previous works have demonstrated how local charge correlations and molecular connectivity can drastically affect the phase behavior of coacervates. The precise location of charges along the chain therefore dramatically influences the local charge correlations, which consequently influences the phase behavior of coacervates. We investigate the effect of charge patterning along the polymer chain on the phase behavior of coacervates in the framework of the Restricted Primitive Model using Gibbs Ensemble Monte Carlo simulations. Our results show that charge patterning dramatically changes the phase behavior of polymer coacervates, which contrasts with the predictions of the classical Voorn-Overbeek theory. This provides the basis for designing new materials through charge driven self assembly by controlling the positioning of the charged monomers along the chain.

  1. Design and Application of Magnetic Photocatalysts for Water Treatment. The Effect of Particle Charge on Surface Functionality

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    Anna Zielińska-Jurek


    Full Text Available Core-interlayer-shell Fe3O4/SiO2/TiO2, CoFe2O4/SiO2/TiO2 and BaFe12O19/SiO2/TiO2 magnetic photocatalysts were obtained. A water-in-oil microemulsion system with suitable surfactants was used for functionalization of the magnetic core with silica interlayer and TiO2-based photocatalyst. Uncoated and coated particles were characterized by electrophoretic measurements, X-ray diffractometry (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM, specific surface area (BET measurements, diffuse reflectance spectroscopy (DRS and vibrating sample magnetometer (VSM analysis. The pH of the solution and corresponding zeta potential was found to be essential for appropriate formation of ferrite core/silica interlayer/TiO2 shell nanocomposite, since the electrical charge controls interactions during functionalization of the magnetic core particles. Thus, the development of multilayer structure in the isoelectric point (IEP region enhanced adhesion of ferrite, silica and titania particles. The obtained Fe3O4/SiO2/TiO2, CoFe2O4/SiO2/TiO2 and BaFe12O19/SiO2/TiO2 nanocomposites revealed superparamagnetic behavior. The decomposition rate of phenol and carbamazepine allowed to estimate their photocatalytic activity. Progress of photocatalytic mineralization of organic compounds was evaluated by total organic carbon (TOC measurements. Photocatalytic activity measured in four subsequent cycles showed good reusability as no loss of efficiency of phenol degradation was observed.

  2. Accounting for polarization cost when using fixed charge force fields. II. Method and application for computing effect of polarization cost on free energy of hydration. (United States)

    Swope, William C; Horn, Hans W; Rice, Julia E


    Polarization cost is the energy needed to distort the wave function of a molecule from one appropriate to the gas phase to one appropriate for some condensed phase. Although it is not currently standard practice, polarization cost should be considered when deriving improved fixed charge force fields based on fits to certain types of experimental data and when using such force fields to compute observables that involve changes in molecular polarization. Building on earlier work, we present mathematical expressions and a method to estimate the effect of polarization cost on free energy and enthalpy implied by a charge model meant to represent a solvated state. The charge model can be any combination of point charges, higher-order multipoles, or even distributed charge densities, as long as they do not change in response to environment. The method is illustrated by computing the effect of polarization cost on free energies of hydration for the neutral amino acid side chain analogues as predicted using two popular fixed charge force fields and one based on electron densities computed using quantum chemistry techniques that employ an implicit model to represent aqueous solvent. From comparison of the computed and experimental hydration free energies, we find that two commonly used force fields are too underpolarized in their description of the solute-water interaction. On the other hand, a charge model based on the charge density from a hybrid density functional calculation that used an implicit model for aqueous solvent performs well for hydration free energies of these molecules after the correction for dipole polarization is applied. As such, an improved description of the density (e.g., B3LYP, MP2) in conjunction with an implicit solvent (e.g., PCM) or explicit solvent (e.g., QM/MM) approach may offer promise as a starting point for the development of improved fixed charge models for force fields.

  3. High temperature charge amplifier for geothermal applications (United States)

    Lindblom, Scott C.; Maldonado, Frank J.; Henfling, Joseph A.


    An amplifier circuit in a multi-chip module includes a charge to voltage converter circuit, a voltage amplifier a low pass filter and a voltage to current converter. The charge to voltage converter receives a signal representing an electrical charge and generates a voltage signal proportional to the input signal. The voltage amplifier receives the voltage signal from the charge to voltage converter, then amplifies the voltage signal by the gain factor to output an amplified voltage signal. The lowpass filter passes low frequency components of the amplified voltage signal and attenuates frequency components greater than a cutoff frequency. The voltage to current converter receives the output signal of the lowpass filter and converts the output signal to a current output signal; wherein an amplifier circuit output is selectable between the output signal of the lowpass filter and the current output signal.

  4. Electrical charging of aerosol nanoparticles and some practical applications

    Directory of Open Access Journals (Sweden)

    Alonso, M.


    Full Text Available This review article summarizes the main results of recent fundamental research on the electrical charging of nanometer-sized aerosol particles (particle diameter below 10 nm, Knudsen number above about 15, kinetic regime. It covers topics of great relevance to aerosol processing and measurement, such as the effect of the presence of a number of ions on the surface of a nanoparticle on its electrical mobility; the experimental measurement of charging probability / efficiency for particle diameter below 10 nm, both for diffusion and corona discharge type chargers; the effect of particle growth by Brownian coagulation on the charging process; and the examination of after-charging effects downstream of an aerosol neutralizes The last part of this article discusses two practical applications of nanoaerosol charging, namely, the particle size measurement by electrical methods, and some electrostatic effects on the removal of nanoparticles from gas streams.

    El presente artículo es una revisión bibliográfica sobre el cargado eléctrico de aerosoles de nanopartículas (diámetro de partícula inferior a 10 nm, número de Knudsen mayor de 15, régimen cinético. El artículo abarca algunos tópicos de gran interés para el procesado y la medición de aerosoles, tales como el efecto de la presencia de iones en la superficie de la nanopartícula en su movilidad eléctrica; la medición experimental de probabilidad / eficacia de cargado para partículas de diámetro inferior a 10 nm, tanto para cargadores de tipo difusivo como para los de descarga de corona; el efecto del crecimiento de partícula por coagulación browniana en el proceso de cargado; y los efectos de post-cargado corriente abajo del neutralizados En la parte final del artículo, se analizan someramente dos aplicaciones prácticas del cargado eléctrico de nanoaerosoles, a saber, la medición del tamaño de partícula por métodos eléctricos, y algunos efectos electrostáticos en el

  5. Application of a Crystal Septum to Replace a Magnet in a Charged Particle Beam and Study of Dechanneling and Feeding in Effects in a Single Silicon Crystal

    Energy Technology Data Exchange (ETDEWEB)

    Wijayawardana, Ranjith Laxman [State Univ. of New York (SUNY), Albany, NY (United States)


    First part of this thesis describes the first application of a crystal septum to replace a magnetic septum at the Fermilab Meson area M-Bottom secondary beam line. As a result the maximum momentum of the beam that could be transmitted to the experimental area was raised from the magnetic septum limit of 225 Gev/c to the full primary beam momentum of 400 Gev/c. Transmission properties of the crystal septum has been studied at energies of 60, 100 and 200 Gev/c. Beam properties at 200 Gev/c with the crystal septum operation has also been studied. The second part consists of a study of planar (110) and axial <112> feeding-in and dechanneling effects in a single silicon crystal. Three surface barrier semiconductor detectors along the crystal were used to measure the energy loss of the charged particles. For each particle incident and outgoing angles and the energy losses in the three crystal mounted detectors were recorded on magnetic tapes. Channeled particles were identified by their low energy losses. Data was acquired at energies of 30, 60, 100 and 200 Gev for planar channeling and 60 and 100 Gev for axial channeling. Feeding-in effects were observed for both planar and axial cases. The basic probabilistic equation was used to derive a simple theoretical model which contains the characteristic dechanneling and feeding-in lengths. The dechanneling lengths have been calculated for both planar and axial channeling and the incident angle dependence of of feeding-in has been studied for planar channeling at above all energies.

  6. Effective Charge Carrier Utilization in Photocatalytic Conversions. (United States)

    Zhang, Peng; Wang, Tuo; Chang, Xiaoxia; Gong, Jinlong


    Continuous efforts have been devoted to searching for sustainable energy resources to alleviate the upcoming energy crises. Among various types of new energy resources, solar energy has been considered as one of the most promising choices, since it is clean, sustainable, and safe. Moreover, solar energy is the most abundant renewable energy, with a total power of 173 000 terawatts striking Earth continuously. Conversion of solar energy into chemical energy, which could potentially provide continuous and flexible energy supplies, has been investigated extensively. However, the conversion efficiency is still relatively low since complicated physical, electrical, and chemical processes are involved. Therefore, carefully designed photocatalysts with a wide absorption range of solar illumination, a high conductivity for charge carriers, a small number of recombination centers, and fast surface reaction kinetics are required to achieve a high activity. This Account describes our recent efforts to enhance the utilization of charge carriers for semiconductor photocatalysts toward efficient solar-to-chemical energy conversion. During photocatalytic reactions, photogenerated electrons and holes are involved in complex processes to convert solar energy into chemical energy. The initial step is the generation of charge carriers in semiconductor photocatalysts, which could be enhanced by extending the light absorption range. Integration of plasmonic materials and introduction of self-dopants have been proved to be effective methods to improve the light absorption ability of photocatalysts to produce larger amounts of photogenerated charge carriers. Subsequently, the photogenerated electrons and holes migrate to the surface. Therefore, acceleration of the transport process can result in enhanced solar energy conversion efficiency. Different strategies such as morphology control and conductivity improvement have been demonstrated to achieve this goal. Fine-tuning of the

  7. Screening effect on nanostructure of charged gel

    DEFF Research Database (Denmark)

    Sugiyama, M; Annaka, M; Hino, M


    Charge screening effects on nanostructures of N-isopropylacrylamide-sodium acrylate (NIPA-SA) and -acrylic acid (NIPA-AAc) gels are investigated with small-angle neutron scattering. The NIPA-SA and NIPA-AAc gels with low water content exhibit microphase separations with different dimensions....... The dehydrated NIPA-SA gel also makes the microphase separation but the dehydrated NIPA-AAc gel does not. These results indicate that ionic circumstance around charged bases strongly affects the nanostructures both of the dehydrated gel and the gel with low water content. (C) 2004 Elsevier B. V. All rights...

  8. Induced charge effects on electrokinetic entry flow (United States)

    Prabhakaran, Rama Aravind; Zhou, Yilong; Zhao, Cunlu; Hu, Guoqing; Song, Yongxin; Wang, Junsheng; Yang, Chun; Xuan, Xiangchun


    Electrokinetic flow, due to a nearly plug-like velocity profile, is the preferred mode for transport of fluids (by electroosmosis) and species (by electrophoresis if charged) in microfluidic devices. Thus far there have been numerous studies on electrokinetic flow within a variety of microchannel structures. However, the fluid and species behaviors at the interface of the inlet reservoir (i.e., the well that supplies the fluid and species) and microchannel are still largely unexplored. This work presents a fundamental investigation of the induced charge effects on electrokinetic entry flow due to the polarization of dielectric corners at the inlet reservoir-microchannel junction. We use small tracing particles suspended in a low ionic concentration fluid to visualize the electrokinetic flow pattern in the absence of Joule heating effects. Particles are found to get trapped and concentrated inside a pair of counter-rotating fluid circulations near the corners of the channel entrance. We also develop a depth-averaged numerical model to understand the induced charge on the corner surfaces and simulate the resultant induced charge electroosmosis (ICEO) in the horizontal plane of the microchannel. The particle streaklines predicted from this model are compared with the experimental images of tracing particles, which shows a significantly better agreement than those from a regular two-dimensional model. This study indicates the strong influences of the top/bottom walls on ICEO in shallow microchannels, which have been neglected in previous two-dimensional models.

  9. Space charge effect in an accelerated beam

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    G. Stupakov


    Full Text Available It is usually assumed that the space charge effects in relativistic beams scale with the energy of the beam as γ^{-2}, where γ is the relativistic factor. We show that for a beam accelerated in the longitudinal direction there is an additional space charge effect in free space that scales as E/γ, where E is the accelerating field. This field has the same origin as the “electromagnetic mass of the electron” discussed in textbooks on electrodynamics. It keeps the balance between the kinetic energy of the beam and the energy of the electromagnetic field of the beam. We then consider the effect of this field on a beam generated in an rf gun and calculate the energy spread produced by this field in the beam.

  10. State-of-Charge Indication in Portable Applications

    NARCIS (Netherlands)

    Pop, V.; Bergveld, H.J.; Notten, P.H.L.; Regtien, Paulus P.L.


    The known methods of state-of-charge (SoC) indication in portable applications are not accurate enough under all practical conditions. The method presented in this paper aims at designing and testing an SoC indication system capable of predicting the remaining capacity of the battery and the

  11. Charging of ice-vapor interfaces: applications to thunderstorms

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    J. Nelson


    Full Text Available The build-up of intrinsic Bjerrum and ionic defects at ice-vapor interfaces electrically charges ice surfaces and thus gives rise to many phenomena including thermoelectricity, ferroelectric ice films, sparks from objects in blizzards, electromagnetic emissions accompanying cracking in avalanches, glaciers, and sea ice, and charge transfer during ice-ice collisions in thunderstorms. Fletcher's theory of the ice surface in equilibrium proposed that the Bjerrum defects have a higher rate of creation at the surface than in the bulk, which produces a high concentration of surface D defects that then attract a high concentration of OH- ions at the surface. Here, we add to this theory the effect of a moving interface caused by growth or sublimation. This effect can increase the amount of ionic surface charges more than 10-fold for growth rates near 1 mm s-1 and can extend the spatial separation of interior charges in qualitative agreement with many observations. In addition, ice-ice collisions should generate sufficient pressure to melt ice at the contact region and we argue that the ice particle with the initially sharper point at contact loses more mass of melt than the other particle. A simple analytic model of this process with parameters that are consistent with observations leads to predicted collisional charge exchange that semiquantitatively explains the negative charging region of thunderstorms. The model also has implications for snowflake formation, ferroelectric ice, polarization of ice in snowpacks, and chemical reactions in ice surfaces

  12. Versatile charge transfer through anthraquinone films for electrochemical sensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Venarusso, Luna B. [Department of Chemistry, Universidade Federal de Mato Grosso do Sul, Caixa Postal 549, Campo Grande, MS 79070-900 (Brazil); Tammeveski, Kaido [Institute of Chemistry, University of Tartu, Ravila 14a, 50411 Tartu (Estonia); Maia, Gilberto, E-mail: [Department of Chemistry, Universidade Federal de Mato Grosso do Sul, Caixa Postal 549, Campo Grande, MS 79070-900 (Brazil)


    Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed to study the effect of anthraquinone (AQ) films on the charge transfer rate of {beta}-nicotinamide adenine dinucleotide (NAD{sup +}), dopamine (DA), and ferricyanide on glassy carbon (GC) electrodes in solutions of different pH. Maximum blocking action on the Fe(CN){sub 6}{sup 3-} redox probe was observed at pH 7 and open-circuit potential (OCP). However, maximum electron hopping effect was observed at pH 9 at both -0.58 V and -0.85 V for Fe(CN){sub 6}{sup 3-}, pH 7 at -0.58 V for NAD{sup +}, and pH 9 at -0.58 V for DA, suggesting that electron hopping in AQ films on a GC surface is dependent on both pH and electrode potential. These findings lend support for the application of these films in the detection of soluble redox probes such as NAD{sup +} and DA at biological pH values (from 7 to 9).

  13. Charge detection mass spectrometry: Instrumentation & applications to viruses (United States)

    Pierson, Elizabeth E.

    For over three decades, electrospray ionization (ESI) has been used to ionize non-covalent complexes and subsequently transfer the intact ion into the gas phase for mass spectrometry (MS) analysis. ESI generates a distribution of multiple charged ions, resulting in an m/z spectrum comprised of a series of peaks, known as a charge state envelope. To obtain mass information, the number of charges for each peak must be deduced. For smaller biological analytes like peptides, the charge states are sufficiently resolved and this process is straightforward. For macromolecular complexes exceeding ~100 kDa, this process is complicated by the broadening and shifting of charge states due to incomplete desolvation, salt adduction, and inherent mass heterogeneity. As the analyte mass approaches the MDa regime, the m/z spectrum is often comprised of a broad distribution of unresolved charge states. In such cases, mass determination is precluded. Charge detection mass spectrometry (CDMS) is an emerging MS technique for determining the masses of heterogeneous, macromolecular complexes. In CDMS, the m/z and z of single ions are measured concurrently so that mass is easily calculated. With this approach, deconvolution of an m/z spectrum is unnecessary. This measurement is carried out by passing macroions through a conductive cylinder. The induced image charge on the cylindrical detector provides information about m/z and z: the m/z is related to its time-of-flight through the detector, and the z is related to the intensity of the image charge. We have applied CDMS to study the self-assembly of virus capsids. Late-stage intermediates in the assembly of hepatitis B virus, a devastating human pathogen, have been identified. This is the first time that such intermediates have been detected and represent a significant advancement towards understanding virus capsid assembly. CDMS has also been used to identify oversized, non-icosahedral polymorphs in the assembly of woodchuck hepatitis

  14. Plasma effect in silicon charge coupled devices (CCDs)

    Energy Technology Data Exchange (ETDEWEB)

    Estrada, J., E-mail: [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Molina, J., E-mail: [Facultad de Ingenieria, Universidad Nacional de Asuncion, Laboratorio de Mecanica y Energia, Campus de la UNA, San Lorenzo 2160 (Paraguay); Blostein, J.J., E-mail: [CONICET (Argentina); Centro Atomico Bariloche, Comision Nacional de Energia Atomica, Bariloche (Argentina); Fernandez, G., E-mail: [Universidad Nacional del Sur, Bahia Blanca (Argentina)


    Plasma effect is observed in CCDs exposed to heavy ionizing {alpha}-particles with energies in the range 0.5-5.5 MeV. The results obtained for the size of the charge clusters reconstructed on the CCD pixels agree with previous measurements in the high energy region ({>=}3.5 MeV). The measurements were extended to lower energies using {alpha}-particles produced by (n,{alpha}) reactions of neutrons in a {sup 10}B target. The effective linear charge density for the plasma column is measured as a function of energy. The results demonstrate the potential for high position resolution in the reconstruction of {alpha} particles, which opens an interesting possibility for using these detectors in neutron imaging applications.

  15. Charge renormalization for effective interactions of colloids at water interfaces


    Frydel, D.; Dietrich, S.; Oettel, M.


    We analyze theoretically the electrostatic interaction of surface-charged colloids at water interfaces with special attention to the experimentally relevant case of large charge densities on the colloid-water interface. Whereas linear theory predicts an effective dipole potential the strength of which is proportional to the square of the product of charge density and screening length, nonlinear charge renormalization effects change this dependence to a weakly logarithmic one. These results ap...

  16. Physics of new methods of charged particle acceleration collective effects in dense charged particle ensembles

    CERN Document Server

    Bonch-Osmolovsky, A G


    This volume discusses the theory of new methods of charged particle acceleration and its physical and mathematical descriptions. It examines some collective effects in dense charged particle ensembles, and traces the history of the development of the field of accelerator physics.

  17. Evidence of Space-Charge Effects in Thermal Poling

    DEFF Research Database (Denmark)

    Wu, X.; Arentoft, Jesper; Wong, D.


    The in situ thermal poling processes in germanosilicate fibers for positive and negative poling voltages are significantly different. Thermal poling of silica fibers consists of two processes: the faster linear process of charge migration and the subsequent single exponential process of charge...... ionization. Both the shielding electrical field due to charge migration and the ionization electrical field due to charge ionization are able to be frozen-in at room temperature acid lead to the residual linear electrooptic effects, The observations support that the mechanism of the induced electrooptic...... effects is based on space charge electrical fields instead of dipole/bond orientation....

  18. Counterion Condensation and Effective Charge of PAMAM Dendrimers

    Directory of Open Access Journals (Sweden)

    Ulrich Scheler


    Full Text Available PAMAM dendrimers are used as a model system to investigate the effects of counterion condensation and the effective charge for spherical polyelectrolytes. Because of their amino groups, PAMAM dendrimers are weak polyelectrolytes. Lowering the pH results in an increasing protonation of the amino groups which is monitored via the proton chemical shifts of the adjacent CH2 groups. The effective charge is determined from a combination of diffusion and electrophoresis NMR. The fraction of the charges, which are effective for the interaction with an external electric field or other charges, decreases with increasing generation (size of the dendrimers.

  19. 47 CFR 1.1104 - Schedule of charges for applications and other filings for media services. (United States)


    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Schedule of charges for applications and other... GENERAL PRACTICE AND PROCEDURE Schedule of Statutory Charges and Procedures for Payment § 1.1104 Schedule of charges for applications and other filings for media services. Remit manual filings and/or payment...

  20. 12 CFR 226.5a - Credit and charge card applications and solicitations. (United States)


    ... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Credit and charge card applications and... required under this section on or with a solicitation or an application to open a credit or charge card... offer by the card issuer to open a credit or charge card account that does not require the consumer to...

  1. Effect of electrical charges and fields on injury and viability of airborne bacteria. (United States)

    Mainelis, Gediminas; Górny, Rafał L; Reponen, Tiina; Trunov, Mikhaylo; Grinshpun, Sergey A; Baron, Paul; Yadav, Jagjit; Willeke, Klaus


    In this study, the effects of the electric charges and fields on the viability of airborne microorganisms were investigated. The electric charges of different magnitude and polarity were imparted on airborne microbial cells by a means of induction charging. The airborne microorganisms carrying different electric charge levels were then extracted by an electric mobility analyzer and collected using a microbial sampler. It was found that the viability of Pseudomonas fluorescens bacteria, used as a model for sensitive bacteria, carrying a net charge from 4100 negative to 30 positive elementary charges ranged between 40% and 60%; the viability of the cells carrying >2700 positive charges was below 1.5%. In contrast, the viability of the stress-resistant spores of Bacillus subtilis var. niger (used as simulant of anthrax-causing Bacillus anthracis spores when testing bioaerosol sensors in various studies), was not affected by the amount of electric charges on the spores. Because bacterial cells depend on their membrane potential for basic metabolic activities, drastic changes occurring in the membrane potential during aerosolization and the local electric fields induced by the imposed charges appeared to affect the sensitive cells' viability. These findings facilitate applications of electric charging for environmental control purposes involving sterilization of bacterial cells by imposing high electric charges on them. The findings from this study can also be used in the development of new bioaerosol sampling methods based on electrostatic principles. Copyright 2002 Wiley Periodicals, Inc.

  2. Variable Charge of Ultisols due to Phosphate Application and Incubation Time

    Directory of Open Access Journals (Sweden)

    Muhammad Mahbub


    Full Text Available The laboratoryexperiment was conducted to study the effect of phosphate (P application and its incubation time on pHo (pH at thepoint of zero charge and variable charge of ultisols . The determined parameters were pHo and variable surfacecharges.Soil samples were added by 0, 375 and 1,125 mg P kg-1 (or 0, 50 and 150% of the P sorption maximum,respectively. Then, they were incubated for 2, 4, 6 and 8 weeks. The variable surface-charges and pHo weredetermined by using the activity of potential determining ions (H+ and OH- within two salt concentrations as counterions (0.1N and 0.001N CaCl2 through a potentiometric titration method. The results were indicated that the high Psorption and 766 mg P kg-1 in maximum sorption were due to high contents in clay fractions and aluminum as well aslow pH of experimental soil. Application of P and incubation time were able to decrease pHo and to increase negativesurface-charges. Additionals of 375 and 1.125 mg P kg-1 incubated for 8 weeks gave the value of pHo 2.86 and 2.69;as well as the magnitude of negative charges 14.48 and 16.76 cmol(, respectively (both for 0.001N CaCl2.For pH > pHo (the characteristic of variable charge soils, the higher the salt (CaCl2 concentration and pH solution,the higher the negative surface-charge.

  3. Understanding the effect of space charge on instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Blaskiewicz, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Chao, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Institute for Materials and Energy Science (SIMES); Chin, Y. H. [National Lab. for High Energy Physics (KEK), Ibaraki (Japan)


    The combined effect of space charge and wall impedance on transverse instabilities is an important consideration in the design and operation of high intensity hadron machines as well as an intrinsic academic interest. This study explores the combined effects of space charge and wall impedance using various simplified models in an attempt to produce a better understanding of their interplay.

  4. Effects of charged particles on human tumor cells

    Directory of Open Access Journals (Sweden)

    Kathryn D Held


    Full Text Available The use of charged particle therapy in cancer treatment is growing rapidly, in large part because the exquisite dose localization of charged particles allows for higher radiation doses to be given to tumor tissue while normal tissues are exposed to lower doses and decreased volumes of normal tissues are irradiated. In addition, charged particles heavier than protons have substantial potential clinical advantages because of their additional biological effects including greater cell killing effectiveness, decreased radiation resistance of hypoxic cells in tumors and reduced cell cycle dependence of radiation response. These biological advantages depend on many factors such as endpoint, cell or tissue type, dose, dose rate or fractionation, charged particle type and energy, and oxygen concentration. This review summarizes the unique biological advantages of charged particle therapy and highlights recent research and areas of particular research needs, such as quantification of Relative Biological Effectiveness (RBE for various tumor types and radiation qualities, role of genetic background of tumor cells in determining response to charged particles, sensitivity of cancer stem-like cells to charged particles, role of charged particles in tumors with hypoxic fractions and importance of fractionation, including use of hypofractionation, with charged particles.

  5. Effects of polarization-charge shielding in microwave heating

    Energy Technology Data Exchange (ETDEWEB)

    Lin, M. S.; Lin, S. M.; Chiang, W. Y.; Barnett, L. R.; Chu, K. R., E-mail: [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China)


    Heating of dielectric objects by radio frequency (RF) and microwaves has long been a method widely employed in scientific research and industrial applications. However, RF and microwave heating are often susceptible to an excessive temperature spread due to uneven energy deposition. The current study elucidates an important physical reason for this difficulty and proposes an effective remedy. Non-spherical samples are placed in an anechoic chamber, where it is irradiated by a traveling microwave wave with 99% intensity uniformity. Polarization charges induced on the samples tend to partially cancel the incident electric field and hence reduce the heating rate. The polarization-charge shielded heating rate is shown to be highly dependent on the sample's shape and its orientation relative to the wave electric field. For samples with a relatively high permittivity, the resultant uneven heating can become a major cause for the excessive temperature spread. It is also demonstrated that a circularly polarized wave, with its rapidly rotating electric field, can effectively even out the heating rate and hence the temperature spread.

  6. Charges for plastic bags : Motivational and behavioral effects

    NARCIS (Netherlands)

    Jakovcevic, Adriana; Steg, Linda; Mazzeo, Nadia; Caballero, Romina; Franco, Paul; Putrino, Natalia; Favara, Jesica


    Two field studies tested the effects of a charge for single-use plastic bags recently implemented in Buenos Aires City, Argentina. Study 1 showed a greater increase in consumers' own bag use after the charge was introduced in supermarkets where the policy was introduced, in comparison to control

  7. From electrode charges on dielectric elastomers to trapped charges and electric dipoles in electrets and ferroelectrets: fundamental and applications-relevant aspects of diversity in electroactive polymers (United States)

    Gerhard, Reimund


    Some recent developments in the areas of soft and basically incompressible electro-electrets (dielectric elastomers) with large strains, of anisotropic polymer ferro- or piezo-electrets with quasi-ferroelectric behavior, of moleculardipole electrets with significant ferro-, pyro- and piezo-electricity, and of space-charge polymer electrets with locally stabilised charges are described. Such materials may be applied, e.g., in soft actuators, energy harvesters and flexible and stretchable sensors for devices such as artificial muscles, electrically controllable refractive and diffractive optics, flexible pyroelectric detectors, motion and displacement sensors, earphones and microphones, ultrasonic transducers, air filters, radiation dosimeters, etc. The performance of dielectric elastomers for actuator, energy-harvester and sensor applications relies on a high relative permittivity and a low elastic modulus. High densities of electric charges in the electrodes are required in order to provide large Maxwell stresses or high energy densities. Significant amounts of localised or trapped charges, as well as electric dipoles from pairs of charges, lead to useful electro-mechanical and mechano-electrical effects (or inverse and direct piezoelectricity, respectively) if they are properly arranged in dielectric materials with extremely low conductivities. Space-charge electret films and ferroelectret systems should exhibit thermal and long-term stability of the trapped charges within the respective materials. Ferroelectric polymers and other polar polymers show useful piezo- and pyroelectric properties if their polymer-chain conformations allow for parallel packing of the molecular dipoles. Space-charge and molecular-dipole electrets are widely applied, e.g. in microphones, air filters, radiation dosimeters, ultrasonic transducers, etc. Basically, the performance of all electro-active polymers relies on the attraction (and repulsion) of electric charges and thus directly on

  8. Direct Simulation Monte Carlo exploration of charge effects on aerosol evolution (United States)

    Palsmeier, John F.

    Aerosols are potentially generated both during normal operations in a gas cooled Generation IV nuclear reactor and in all nuclear reactors during accident scenarios. These aerosols can become charged due to aerosol generation processes, radioactive decay of associated fission products, and ionizing atmospheres. Thus the role of charge on aerosol evolution, and hence on the nuclear source term, has been an issue of interest. There is a need for both measurements and modeling to quantify this role as these effects are not currently accounted for in nuclear reactor modeling and simulation codes. In this study the role of charge effects on the evolution of a spatially homogenous aerosol was explored via the application of the Direct Simulation Monte Carlo (DSMC) technique. The primary mechanisms explored were those of coagulation and electrostatic dispersion. This technique was first benchmarked by comparing the results obtained from both monodisperse and polydisperse DSMC evolution of charged aerosols with the results obtained by respectively deterministic and sectional techniques. This was followed by simulation of several polydisperse charged aerosols. Additional comparisons were made between the evolutions of charged and uncharged aerosols. The results obtained using DSMC in simple cases were comparable to those obtained from other techniques, without the limitations associated with more complex cases. Multicomponent aerosols of different component densities were also evaluated to determine the charge effects on their evolution. Charge effects can be significant and further explorations are warranted.

  9. Spacecraft environments interactions: Protecting against the effects of spacecraft charging (United States)

    Herr, J. L.; Mccollum, M. B.


    The effects of the natural space environments on spacecraft design, development, and operation are the topic of a series of NASA Reference Publications currently being developed by the Electromagnetics and Environments Branch, Systems Analysis and Integration Laboratory, Marshall Space Flight Center. This primer, second in the series, describes the interactions between a spacecraft and the natural space plasma. Under certain environmental/spacecraft conditions, these interactions result in the phenomenon known as spacecraft charging. It is the focus of this publication to describe the phenomenon of spacecraft charging and its possible adverse effects on spacecraft and to present the key elements of a Spacecraft Charging Effects Protection Plan.

  10. Acoustic charge manipulation in semiconductor nanostructures for optical applications

    Energy Technology Data Exchange (ETDEWEB)

    Voelk, Stefan


    Within this thesis, the influence of a surface acoustic wave (SAW) on the luminescence of semiconductor nanostructures is investigated. Beginning with the physics of low-dimensional semiconductor structures, the quantum mechanical and optical properties of quantum dot (QD) systems are discussed. In particular, intrinsic parameters of QDs such as morphology, composition, strain and occupation with carriers are taken into account. Subsequently, the influence of an applied electric field and of externally induced strain are introduced. From this general approach, the discussion is focused to quantum posts (QPs) which are columnar shaped semiconductor nanostructures. In contrast to conventional self-assembled QDs, the height of the QPs can be controlled by the epitaxial growth process. Due to the adjustable height, electronic states and therefore the exciton transition energies can be tailored. Furthermore, QPs are embedded in a matrix-quantum-well structure which has important influence on the carrier dynamic if a SAW is excited on the sample. Mainly, two effects have to be considered regarding the interaction of charge carriers with SAWs: deformation potential coupling and acousto-electric coupling. For the investigated material and used SAW frequencies, acousto-electric coupling dominates the interaction between charges and SAW. For a quantum well (QW) structure, the periodic band modulation dissociates excitons into sequential stripes of electrons and holes which then are conveyed by the SAW. This so called bipolar transport or charge conveyance effect can be used to inject carriers into remote QD structures and has already been demonstrated for QD ensembles. The injection of carriers into individual quantum posts is successfully demonstrated for the first time within this work. The spectrally resolved photoluminescence (PL) data of individual QPs show an unexpected switching of PL lines which cannot be induced by varying other parameters, e.g. the laser intensity

  11. Space Charge Effects in Single Molecular Devices (United States)

    Dunlap, David H.; Malliaras, George G.


    Strong negative differential resistance (NDR) has been recently observed in p-conjugated oligo (phenyleneethynylene) single-molecular devices consisting of two parallel metal (Au) electrodes which are separated by a self-assembled monolayer having a thickness on the order of 2nm [1]. The sudden drop in current suggests that nonlinear feedback associated electron transport through intermediate molecular states may be responsible for the observed NDR. We propose that the transfer of charge from the cathode to the anode takes place via nearest-neighbor hopping between two weakly coupled oligomer states. In such a case, the current is highest when the energies of the two states are coincident, and is suppressed when the voltage drop between them is sufficient to take them far out of resonance. The modification of the voltages within the junction due to accumulated space charge causes the states to become pinned. We show that this collective behavior enhances the abruptness of the NDR, and under appropriate circumstances leads to a triangularly shaped hysteresis loop in the current-voltage relation. [1] M. A. Reed, J. Chen, W. Wang, D. W. Price, A. M. Rawlett, and J. M. Tour, Appl. Phys. Lett 78, 3735 (2001)

  12. Effect of thermal fluctuations on a charged dilatonic black Saturn

    Directory of Open Access Journals (Sweden)

    Behnam Pourhassan


    Full Text Available In this paper, we will analyze the effect of thermal fluctuations on the thermodynamics of a charged dilatonic black Saturn. These thermal fluctuations will correct the thermodynamics of the charged dilatonic black Saturn. We will analyze the corrections to the thermodynamics of this system by first relating the fluctuations in the entropy to the fluctuations in the energy. Then, we will use the relation between entropy and a conformal field theory to analyze the fluctuations in the entropy. We will demonstrate that similar physical results are obtained from both these approaches. We will also study the effect of thermal fluctuations on the phase transition in this charged dilatonic black Saturn.

  13. Effect of thermal fluctuations on a charged dilatonic black Saturn

    Energy Technology Data Exchange (ETDEWEB)

    Pourhassan, Behnam, E-mail: [School of Physics, Damghan University, Damghan (Iran, Islamic Republic of); Faizal, Mir, E-mail: [Department of Physics and Astronomy, University of Lethbridge, Lethbridge, AB T1K 3M4 (Canada)


    In this paper, we will analyze the effect of thermal fluctuations on the thermodynamics of a charged dilatonic black Saturn. These thermal fluctuations will correct the thermodynamics of the charged dilatonic black Saturn. We will analyze the corrections to the thermodynamics of this system by first relating the fluctuations in the entropy to the fluctuations in the energy. Then, we will use the relation between entropy and a conformal field theory to analyze the fluctuations in the entropy. We will demonstrate that similar physical results are obtained from both these approaches. We will also study the effect of thermal fluctuations on the phase transition in this charged dilatonic black Saturn.

  14. Effect of Thermal Fluctuations on a Charged Dilatonic Black Saturn

    CERN Document Server

    Pourhassan, Behnam


    In this paper, we will analyze the effect of thermal fluctuations on the thermodynamics of a charged dilatonic black Saturn. These thermal fluctuations will correct the thermodynamics of the charged dilatonic black Saturn. We will analyze the corrections to the thermodynamics of this system by first relating the fluctuations in the entropy to the fluctuations in the energy. Then, we will use the relation between entropy and a conformal field theory to analyze the fluctuations in the entropy. We will demonstrate that similar physical results are obtained from both these approaches. We will also study the effect of thermal fluctuations on the phase transition in this charged dilatonic black Saturn.

  15. Effect of Stochastic Charge Fluctuations on Dust Dynamics (United States)

    Matthews, Lorin; Shotorban, Babak; Hyde, Truell


    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.

  16. Simulation of space charge effects in resistive plate chambers

    CERN Document Server

    Lippmann, Christian


    Multigap resistive plate chambers with 0.3-mm gas gaps operated in avalanche mode at atmospheric pressure have reached timing accuracies below 50 ps (standard deviation) with efficiencies above 99% . The avalanches in high homogeneous electric fields of 100 kV/cm are strongly influenced by space charge effects which are the main topic of this paper. We extend a previously discussed Monte Carlo simulation model of avalanches in resistive plate chambers by the dynamic calculation of the electric field in the avalanches. We complete the previously presented results on time resolution and efficiency data with simulated charge spectra. The simulated data shows good agreement with measurements. The detailed simulation of the avalanche saturation due to the space charge fields explains the small observed charges, the shape of the spectra, and the linear increase of average charges with high voltage. (22 refs).

  17. Surface charge effects in protein adsorption on nanodiamonds (United States)

    Aramesh, M.; Shimoni, O.; Ostrikov, K.; Prawer, S.; Cervenka, J.


    Understanding the interaction of proteins with charged diamond nanoparticles is of fundamental importance for diverse biomedical applications. Here we present a thorough study of protein binding, adsorption kinetics and structure on strongly positively (hydrogen-terminated) and negatively (oxygen-terminated) charged nanodiamond particles using a quartz crystal microbalance by dissipation and infrared spectroscopy. By using two model proteins (bovine serum albumin and lysozyme) of different properties (charge, molecular weight and rigidity), the main driving mechanism responsible for the protein binding to the charged nanoparticles was identified. Electrostatic interactions were found to dominate the protein adsorption dynamics, attachment and conformation. We developed a simple electrostatic model that can qualitatively explain the observed adsorption behaviour based on charge-induced pH modifications near the charged nanoparticle surfaces. Under neutral conditions, the local pH around the positively and negatively charged nanodiamonds becomes very high (11-12) and low (1-3) respectively, which has a profound impact on the protein charge, hydration and affinity to the nanodiamonds. Small proteins (lysozyme) were found to form multilayers with significant conformational changes to screen the surface charge, while larger proteins (albumin) formed monolayers with minor conformational changes. The findings of this study provide a step forward toward understanding and eventually predicting nanoparticle interactions with biofluids.Understanding the interaction of proteins with charged diamond nanoparticles is of fundamental importance for diverse biomedical applications. Here we present a thorough study of protein binding, adsorption kinetics and structure on strongly positively (hydrogen-terminated) and negatively (oxygen-terminated) charged nanodiamond particles using a quartz crystal microbalance by dissipation and infrared spectroscopy. By using two model proteins

  18. Electrophoresis of a charge-regulated soft sphere: importance of effective membrane charge. (United States)

    Tseng, Shiojenn; Hsieh, Tsung-Hsien; Yeh, Li-Hsien; Wang, Nan; Hsu, Jyh-Ping


    The importance of the effective membrane charge on the electrophoretic behavior of a soft spherical particle comprising a rigid core and a charge-regulated membrane layer, mimicking both inorganic and biological colloids, is investigated. The mobility of the particle is simulated under various conditions by varying the double layer thickness, the bulk solution pH, and the charged conditions of the membrane layer. Several interesting electrophoretic behaviors that are of practical significance, are observed. For example, the particle mobility can be controlled by adjusting its properties such as the ratios of (acidic equilibrium constant/basic equilibrium constant) and (concentration of acidic functional groups/that of basic functional groups). Double layer polarization (DLP) is found to render the soft particle having behaviors different from those of the corresponding rigid particle. For instance, DLP can either be intensified or weakened, depending upon the strength of the hydrodynamic force and the electric force acting on the membrane layer. As the bulk electrolyte concentration increases in a certain range, because double layer shrinks into the membrane layer, its effective charge density increases, so is the particle mobility. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Signal processing applications of massively parallel charge domain computing devices (United States)

    Fijany, Amir (Inventor); Barhen, Jacob (Inventor); Toomarian, Nikzad (Inventor)


    The present invention is embodied in a charge coupled device (CCD)/charge injection device (CID) architecture capable of performing a Fourier transform by simultaneous matrix vector multiplication (MVM) operations in respective plural CCD/CID arrays in parallel in O(1) steps. For example, in one embodiment, a first CCD/CID array stores charge packets representing a first matrix operator based upon permutations of a Hartley transform and computes the Fourier transform of an incoming vector. A second CCD/CID array stores charge packets representing a second matrix operator based upon different permutations of a Hartley transform and computes the Fourier transform of an incoming vector. The incoming vector is applied to the inputs of the two CCD/CID arrays simultaneously, and the real and imaginary parts of the Fourier transform are produced simultaneously in the time required to perform a single MVM operation in a CCD/CID array.

  20. Image charge effects in the nonequilibrium Anderson-Holstein model (United States)

    Perfetto, E.; Stefanucci, G.


    Image charge effects in nanoscale junctions with strong electron-phonon coupling open the way to unexplored physical scenarios. We propose a simple and still accurate many-body approach to deal with the simultaneous occurrence of the Franck-Condon blockade and the screening-induced enhancement of the polaron mobility. A transparent analytic expression for the polaron decay rate is derived and the dependence on the strength and range of the screening is highlighted. This allows us to interpret and explain several transient and steady-state features of the electrical current. Remarkably, we find that the competition between the charge blocking due to the electron-phonon interaction and the charge deblocking due to the image charges gives rise to a novel mechanism of negative differential conductance. An experimental setup to observe this phenomenon is discussed.

  1. Physiochemical charge stabilization of silver nanoparticles and its antibacterial applications (United States)

    Vanitha, G.; Rajavel, K.; Boopathy, G.; Veeravazhuthi, V.; Neelamegam, P.


    Environmental standardization and stabilization of surface charges of silver nanoparticles (AgNPs) is important in biological systems and interest in bio-interfacial interaction. Different synthesized AgNPs in chemical reduced (AgNO3 (0.01, 0.1 and 0.5 M); NaBH4 and Na3C6H5O7) garnered for analysis of physico-chemical charge stabilization by means of different pH (1-13) and ionic interferences (NaCl, Ca(NO3)2, Na2CO3 and NaNO3). The uniform sized (size: ∼22 nm) and highly charged (zeta potential: -37.9 mV) AgNPs with uniform dispersion remains unaltered in high ionic interferences. Highest antifungal activity of AgNPs against Candida albicans and moderate activity against Staphylococcus aureus are correlated.

  2. Large Seebeck effect by charge-mobility engineering. (United States)

    Sun, Peijie; Wei, Beipei; Zhang, Jiahao; Tomczak, Jan M; Strydom, A M; Søndergaard, M; Iversen, Bo B; Steglich, Frank


    The Seebeck effect describes the generation of an electric potential in a conducting solid exposed to a temperature gradient. In most cases, it is dominated by an energy-dependent electronic density of states at the Fermi level, in line with the prevalent efforts towards superior thermoelectrics through the engineering of electronic structure. Here we demonstrate an alternative source for the Seebeck effect based on charge-carrier relaxation: a charge mobility that changes rapidly with temperature can result in a sizeable addition to the Seebeck coefficient. This new Seebeck source is demonstrated explicitly for Ni-doped CoSb3, where a marked mobility change occurs due to the crossover between two different charge-relaxation regimes. Our findings unveil the origin of pronounced features in the Seebeck coefficient of many other elusive materials characterized by a significant mobility mismatch. When utilized appropriately, this effect can also provide a novel route to the design of improved thermoelectric materials.

  3. Battery Management Systems: Accurate State-of-Charge Indication for Battery-Powered Applications

    NARCIS (Netherlands)

    Pop, V.; Bergveld, H.J.; Danilov, D.; Regtien, Paulus P.L.; Notten, P.H.L.


    Battery Management Systems – Universal State-of-Charge indication for portable applications describes the field of State-of-Charge (SoC) indication for rechargeable batteries. With the emergence of battery-powered devices with an increasing number of power-hungry features, accurately estimating the

  4. Universal state-of-charge indication for portable applications

    NARCIS (Netherlands)

    Pop, V.


    Many leading semiconductors companies (e.g. Philips, Texas Instruments, Microchip, Maxim, etc.) are paying even more attention to accurate State-of-Charge (SoC) indication. Following the technological revolution and the appearance of more power consuming devices on the automotive electronics and

  5. Design of low energy bunch compressors with space charge effects

    Directory of Open Access Journals (Sweden)

    A. He


    Full Text Available In this paper, we explore a method to manipulate low energy electron bunches in a space charge dominated regime, and we use this method to design low energy linac bunch compressors to compress electron bunches in a space charge dominated regime. In the method, we use the space charge effects instead of avoiding them; i.e., we use the space charge forces to generate the required energy chirp instead of the ordinary method which uses the rf accelerating system to generate the chirp. We redefine the concepts of the dispersion function and beta functions in a space charge dominated regime to guide the optimization. Using this method, we study the low energy (5–22 MeV linac bunch compressor design to produce short (∼150  fs and small size (∼30  μm bunches for the electron beam slicing project. The low energy linac bunch compressors work in a space charge dominated regime, and the bunches at the downstream of the gun have a negative energy chirp due to the space charge effects. To provide compression for the negative energy chirped bunch, we design a positive R_{56} dispersive section using a four-dipole chicane with several quadrupole magnets. We have designed low energy linac bunch compressors with different photocathode rf guns. For example, one linac bunch compressor with the BNL photocathode electron rf gun has achieved a low energy bunch with the 166 fs rms bunch length, 28 and 31  μm rms beam size in the vertical and horizontal directions, respectively, at 5 MeV with 50 pC charge. Another example with LBNL’s very-high frequency gun has achieved a low energy bunch with the 128 fs rms bunch length, 42 and 25  μm rms beam size in the vertical and horizontal directions, respectively, at 22 MeV with 200 pC charge.

  6. Electron cloud and space charge effects in the Fermilab Booster

    Energy Technology Data Exchange (ETDEWEB)

    Ng, K.Y.; /Fermilab


    The stable region of the Fermilab Booster beam in the complex coherent-tune-shift plane appears to have been shifted far away from the origin by its intense space charge making Landau damping appear impossible. Simulations reveal a substantial buildup of electron cloud in the whole Booster ramping cycle, both inside the unshielded combined-function magnets and the beam pipes joining the magnets, whenever the secondary-emission yield (SEY) is larger than {approx}1.6. The implication of the electron-cloud effects on the space charge and collective instabilities of the beam is investigated.

  7. Adaptive cost-effective ambient charges under incomplete information

    NARCIS (Netherlands)

    Ermoliev, Y; Nentjes, A

    Established opinion is that in the face of uncertain information on pollution control costs, environmental agencies cannot set ambient charges that enable the realization of desired concentration levels at multiple receptors in a cost-effective way. Although a trial-and-error procedure could result

  8. Effects of acid concentration on intramolecular charge transfer ...

    Indian Academy of Sciences (India)

    Effects of acid concentration on excited state intramolecular charge transfer reaction of 4-(azetidinyl) benzonitrile (P4C) in aprotic (acetonitrile and ethyl acetate) and protic (ethanol) solvents have been studied by means of steady state absorption and fluorescence, and time resolved fluorescence spectroscopic techniques.

  9. Long-lived charge separation and applications in artificial photosynthesis. (United States)

    Fukuzumi, Shunichi; Ohkubo, Kei; Suenobu, Tomoyoshi


    Researchers have long been interested in replicating the reactivity that occurs in photosynthetic organisms. To mimic the long-lived charge separations characteristic of the reaction center in photosynthesis, researchers have applied the Marcus theory to design synthetic multistep electron-transfer (ET) systems. In this Account, we describe our recent research on the rational design of ET control systems, based on models of the photosynthetic reaction center that rely on the Marcus theory of ET. The key to obtaining a long-lived charge separation is the careful choice of electron donors and acceptors that have small reorganization energies of ET. In these cases, the driving force of back ET is located in the Marcus inverted region, where the lifetime of the charge-separated state lengthens as the driving force of back ET increases. We chose porphyrins as electron donors and fullerenes as electron acceptors, both of which have small ET reorganization energies. By linking electron donor porphyrins and electron acceptor fullerenes at appropriate distances, we achieved charge-separated states with long lifetimes. We could further lengthen the lifetimes of charge-separated states by mixing a variety of components, such as a terminal electron donor, an electron mediator, and an electron acceptor, mimicking both the photosynthetic reaction center and the multistep photoinduced ET that occurs there. However, each step in multistep ET loses a fraction of the initial excitation energy during the long-distance charge separation. To overcome this drawback in multistep ET systems, we used designed new systems where we could finely control the redox potentials and the geometry of simple donor-acceptor dyads. These modifications resulted in a small ET reorganization energy and a high-lying triplet excited state. Our most successful example, 9-mesityl-10-methylacridinium ion (Acr(+)-Mes), can undergo a fast photoinduced ET from the mesityl (Mes) moiety to the singlet excited state

  10. Exceptionally Long-Lived Charge Separated State in Zeolitic Imidazolate Framework: Implication for Photocatalytic Applications

    Energy Technology Data Exchange (ETDEWEB)

    Pattengale, Brian [Department; Yang, Sizhuo [Department; Ludwig, John [Department; Huang, Zhuangqun [Department; Zhang, Xiaoyi [X-ray; Huang, Jier [Department


    Zeolitic Imidazolate Frameworks (ZIFs) have emerged as a novel class of porous metal-organic frameworks (MOFs) for catalysis application because of their exceptional thermal and chemical stability. Inspired by the broad absorption of ZIF-67 in UV-visible-near IR region, we explored its excited state and charge separation dynamics, properties essential for photocatalytic applications, using optical (OTA) and X-ray transient absorption (XTA) spectroscopy. OTA results show that an exceptionally long-lived excited state is formed after photoexcitation. This long-lived excited state was confirmed to be the charge separated state with ligandto-metal charge transfer character using XTA. The surprisingly long-lived charge separated state, together with its intrinsic hybrid nature, all point to its potential application in heterogeneous photocatalysis and energy conversion.

  11. Polyelectrolyte assisted charge titration spectrometry: applications to latex and oxide nanoparticles


    Mousseau, F.; Vitorazi, L.; Herrmann, L.; Mornet, S.; Berret, J. -F.


    The electrostatic charge density of particles is of paramount importance for the control of the dispersion stability. Conventional methods use potentiometric, conductometric or turbidity titration but require large amount of samples. Here we report a simple and cost-effective method called polyelectrolyte assisted charge titration spectrometry or PACTS. The technique takes advantage of the propensity of oppositely charged polymers and particles to assemble upon mixing, leading to aggregation ...

  12. Effect of charge imbalance parameter on LEKW in ion-implanted quantum semiconductor plasmas (United States)

    Chaudhary, Sandhya; Yadav, Nishchhal; Ghosh, S.


    In this study we present an analytical investigation on the propagation characteristics of electro-kinetic wave modified through quantum correction term and charge imbalance parameter using quantum hydrodynamic model for an ion-implanted semiconductor plasma. The dispersion relation has been analyzed in two distinct velocity regimes. We found that as the number of negative charges resides on the colloids increases, their role become increasing effective. The present investigation is important for understanding of wave and instability phenomena and can be put to various interesting applications.

  13. The role of acid-base effects on particle charging in apolar media. (United States)

    Gacek, Matthew Michael; Berg, John C


    charging in the context of the many other factors that are important to the phenomenon, including the presence of water, of other components (e.g., synergists and contaminants), and of electric field effects. The goal is the construction of a road map describing the anticipated particle charging behavior in a wide variety of systems, assisting in the choice or development of materials for specific applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. 47 CFR 1.1105 - Schedule of charges for applications and other filings for the wireline competition services. (United States)


    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Schedule of charges for applications and other... COMMUNICATIONS COMMISSION GENERAL PRACTICE AND PROCEDURE Schedule of Statutory Charges and Procedures for Payment § 1.1105 Schedule of charges for applications and other filings for the wireline competition services...

  15. 47 CFR 1.1106 - Schedule of charges for applications and other filings for the enforcement services. (United States)


    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Schedule of charges for applications and other... COMMISSION GENERAL PRACTICE AND PROCEDURE Schedule of Statutory Charges and Procedures for Payment § 1.1106 Schedule of charges for applications and other filings for the enforcement services. Remit manual filings...

  16. 47 CFR 1.1109 - Schedule of charges for applications and other filings for the Homeland services. (United States)


    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Schedule of charges for applications and other... COMMISSION GENERAL PRACTICE AND PROCEDURE Schedule of Statutory Charges and Procedures for Payment § 1.1109 Schedule of charges for applications and other filings for the Homeland services. Remit manual filings and...

  17. Effect of surface charge of immortalized mouse cerebral endothelial cell monolayer on transport of charged solutes. (United States)

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


    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.

  18. Modulation of graphene field effect by heavy charged particle irradiation (United States)

    Cazalas, Edward; Sarker, Biddut K.; Childres, Isaac; Chen, Yong P.; Jovanovic, Igor


    Device architectures based on the two-dimensional material graphene can be used for sensing of electromagnetic and particle radiation. The sensing mechanism may be direct, by absorbance of radiation by the graphene or the immediately adjacent material, and indirect, via the field effect principle, whereby the change in conductivity within a semiconducting absorber substrate induces electric field change at graphene. Here, we report on a graphene field effect transistor (GFET) sensitive to heavy charged particle radiation (α particles) at MeV energies by use of the indirect sensing mechanism. Both the continuous and discrete changes of graphene are observed, and the latter are attributed to single α particle interactions with the GFET. While this study provides the basis for understanding of the irradiation effects, it also opens prospects for the use of GFETs as heavy charged particle detectors.

  19. Spin and charge thermopower effects in the ferromagnetic graphene junction

    Energy Technology Data Exchange (ETDEWEB)

    Vahedi, Javad, E-mail: [Department of Physics, Sari Branch, Islamic Azad University, Sari (Iran, Islamic Republic of); Center for Theoretical Physics of Complex Systems, Institute for Basic Science (IBS), Daejeon (Korea, Republic of); Barimani, Fattaneh [Center for Theoretical Physics of Complex Systems, Institute for Basic Science (IBS), Daejeon (Korea, Republic of)


    Using wave function matching approach and employing the Landauer-Buttiker formula, a ferromagnetic graphene junction with temperature gradient across the system is studied. We calculate the thermally induced charge and spin current as well as the thermoelectric voltage (Seebeck effect) in the linear and nonlinear regimes. Our calculation revealed that due to the electron-hole symmetry, the charge Seebeck coefficient is, for an undoped magnetic graphene, an odd function of chemical potential while the spin Seebeck coefficient is an even function regardless of the temperature gradient and junction length. We have also found with an accurate tuning external parameter, namely, the exchange filed and gate voltage, the temperature gradient across the junction drives a pure spin current without accompanying the charge current. Another important characteristic of thermoelectric transport, thermally induced current in the nonlinear regime, is examined. It would be our main finding that with increasing thermal gradient applied to the junction the spin and charge thermovoltages decrease and even become zero for non zero temperature bias.

  20. Effect of Titanium Dioxide Dopping on Charge Trapping in ...

    African Journals Online (AJOL)

    The charge storage properties of corona charged pure and TiO2 doped polystyrene (PS) films have been studied. Thermally stimulated charge decay and open circuit thermally stimulated charges were measured. A half-value charge decay temperature T1/2 ∼ 140oC is optimum at 3 wt % TiO2 doping. This implies that ...

  1. The single-sink fixed-charge transportation problem: Applications and solution methods

    DEFF Research Database (Denmark)

    Goertz, Simon; Klose, Andreas


    The single-sink fixed-charge transportation problem (SSFCTP) consists in finding a minimum cost flow from a number of supplier nodes to a single demand node. Shipping costs comprise costs proportional to the amount shipped as well as a fixed-charge. Although the SSFCTP is an important special case...... of the well-known fixed-charge transportation problem, just a few methods for solving this problem have been proposed in the literature. After summarising some applications of this problem arising in manufacturing and transportation, we give an overview on approximation algorithms and worst-case results...

  2. Universal Charge Diffusion and the Butterfly Effect in Holographic Theories (United States)

    Blake, Mike


    We study charge diffusion in holographic scaling theories with a particle-hole symmetry. We show that these theories have a universal regime in which the diffusion constant is given by Dc=C vB2/(2 π T ), where vB is the velocity of the butterfly effect. The constant of proportionality C depends only on the scaling exponents of the infrared theory. Our results suggest an unexpected connection between transport at strong coupling and quantum chaos.

  3. Two-Dimensional Transition Metal Dichalcogenides and Their Charge Carrier Mobilities in Field-Effect Transistors (United States)

    Ahmed, Sohail; Yi, Jiabao


    Two-dimensional (2D) materials have attracted extensive interest due to their excellent electrical, thermal, mechanical, and optical properties. Graphene has been one of the most explored 2D materials. However, its zero band gap has limited its applications in electronic devices. Transition metal dichalcogenide (TMDC), another kind of 2D material, has a nonzero direct band gap (same charge carrier momentum in valence and conduction band) at monolayer state, promising for the efficient switching devices (e.g., field-effect transistors). This review mainly focuses on the recent advances in charge carrier mobility and the challenges to achieve high mobility in the electronic devices based on 2D-TMDC materials and also includes an introduction of 2D materials along with the synthesis techniques. Finally, this review describes the possible methodology and future prospective to enhance the charge carrier mobility for electronic devices.

  4. Method of improving heterogeneous oil reservoir polymer flooding effect by positively-charged gel profile control (United States)

    Zhao, Ling; Xia, Huifen


    The project of polymer flooding has achieved great success in Daqing oilfield, and the main oil reservoir recovery can be improved by more than 15%. But, for some strong oil reservoir heterogeneity carrying out polymer flooding, polymer solution will be inefficient and invalid loop problem in the high permeability layer, then cause the larger polymer volume, and a significant reduction in the polymer flooding efficiency. Aiming at this problem, it is studied the method that improves heterogeneous oil reservoir polymer flooding effect by positively-charged gel profile control. The research results show that the polymer physical and chemical reaction of positively-charged gel with the residual polymer in high permeability layer can generate three-dimensional network of polymer, plugging high permeable layer, and increase injection pressure gradient, then improve the effect of polymer flooding development. Under the condition of the same dosage, positively-charged gel profile control can improve the polymer flooding recovery factor by 2.3∼3.8 percentage points. Under the condition of the same polymer flooding recovery factor increase value, after positively-charged gel profile control, it can reduce the polymer volume by 50 %. Applying mechanism of positively-charged gel profile control technology is feasible, cost savings, simple construction, and no environmental pollution, therefore has good application prospect.

  5. Program NAJOCSC and space charge effect simulation in C01

    Energy Technology Data Exchange (ETDEWEB)

    Tang, J.Y.; Chabert, A.; Baron, E


    During the beam tests of the THI project at GANIL, it was found it difficult to increase the beam power above 2 kW at CSS2 extraction. The space charge effect (abbreviated as S.C. effect) in cyclotrons is suspected to play some role in the phenomenon, especially the longitudinal S.C. one and also the coupling between longitudinal and radial motions. The injector cyclotron C01 is studied, and the role played by the S.C. effect in this cyclotron in the THI case is investigated by a simulation method. (K.A.) 12 refs.

  6. 3D Simulations of Space Charge Effects in Particle Beams

    Energy Technology Data Exchange (ETDEWEB)

    Adelmann, A


    For the first time, it is possible to calculate the complicated three-dimensional proton accelerator structures at the Paul Scherrer Institut (PSI). Under consideration are external and self effects, arising from guiding and space-charge forces. This thesis has as its theme the design, implementation and validation of a tracking program for charged particles in accelerator structures. This work form part of the discipline of Computational Science and Engineering (CSE), more specifically in computational accelerator modelling. The physical model is based on the collisionless Vlasov-Maxwell theory, justified by the low density ({approx} 10{sup 9} protons/cm{sup 3}) of the beam and of the residual gas. The probability of large angle scattering between the protons and the residual gas is then sufficiently low, as can be estimated by considering the mean free path and the total distance a particle travels in the accelerator structure. (author)

  7. Cost-effective electric vehicle charging infrastructure siting for Delhi (United States)

    Sheppard, Colin J. R.; Gopal, Anand R.; Harris, Andrew; Jacobson, Arne


    Plug-in electric vehicles (PEVs) represent a substantial opportunity for governments to reduce emissions of both air pollutants and greenhouse gases. The Government of India has set a goal of deploying 6-7 million hybrid and PEVs on Indian roads by the year 2020. The uptake of PEVs will depend on, among other factors like high cost, how effectively range anxiety is mitigated through the deployment of adequate electric vehicle charging stations (EVCS) throughout a region. The Indian Government therefore views EVCS deployment as a central part of their electric mobility mission. The plug-in electric vehicle infrastructure (PEVI) model—an agent-based simulation modeling platform—was used to explore the cost-effective siting of EVCS throughout the National Capital Territory (NCT) of Delhi, India. At 1% penetration in the passenger car fleet, or ˜10 000 battery electric vehicles (BEVs), charging services can be provided to drivers for an investment of 4.4 M (or 440/BEV) by siting 2764 chargers throughout the NCT of Delhi with an emphasis on the more densely populated and frequented regions of the city. The majority of chargers sited by this analysis were low power, Level 1 chargers, which have the added benefit of being simpler to deploy than higher power alternatives. The amount of public infrastructure needed depends on the access that drivers have to EVCS at home, with 83% more charging capacity required to provide the same level of service to a population of drivers without home chargers compared to a scenario with home chargers. Results also depend on the battery capacity of the BEVs adopted, with approximately 60% more charging capacity needed to achieve the same level of service when vehicles are assumed to have 57 km versus 96 km of range.

  8. Large space-charge effects in a nanostructured proton conductor

    Energy Technology Data Exchange (ETDEWEB)

    Haverkate, Lucas A.; Chan, Wing K.; Mulder, Fokko M. [Fundamental Aspects of Materials and Energy, Department of Radiation, Radionuclides, and Reactors, Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629JB Delft (Netherlands)


    Decreasing the dimensions of heterogeneous mixtures of ionic conductors towards the nanoscale results in ionic conduction enhancements, caused by the increased influence of the interfacial space-charge regions. For a composite of TiO{sub 2} anatase and solid acid CsHSO{sub 4}, the strong enhancement of the ionic conductivity at the nanoscale also can be assigned to this space-charge effect. Surprisingly high hydrogen concentrations in the order of 10{sup 21} cm{sup -3} in TiO{sub 2} are measured, which means that about 10% of the available sites for H{sup +} ions are filled on average. Such high concentrations require a specific elaboration of the space-charge model that is explicitly performed here, by taking account of the large occupation numbers on the exhaustible sites. It is shown that ionic defects with negative formation enthalpy reach extremely high concentrations near the interfaces and throughout the material. By performing first-principles density functional theory calculations, it is found that proton insertion from CsHSO{sub 4} into the TiO{sub 2} particles is preferred compared to neutral hydrogen atom insertion and indeed that the formation enthalpy is negative. Moreover, the average proton fractions in TiO{sub 2}, estimated by the theoretical ionic density profiles, are in good agreement with the experimental observations. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Fast Demand Forecast of Electric Vehicle Charging Stations for Cell Phone Application

    Energy Technology Data Exchange (ETDEWEB)

    Majidpour, Mostafa; Qiu, Charlie; Chung, Ching-Yen; Chu, Peter; Gadh, Rajit; Pota, Hemanshu R.


    This paper describes the core cellphone application algorithm which has been implemented for the prediction of energy consumption at Electric Vehicle (EV) Charging Stations at UCLA. For this interactive user application, the total time of accessing database, processing the data and making the prediction, needs to be within a few seconds. We analyze four relatively fast Machine Learning based time series prediction algorithms for our prediction engine: Historical Average, kNearest Neighbor, Weighted k-Nearest Neighbor, and Lazy Learning. The Nearest Neighbor algorithm (k Nearest Neighbor with k=1) shows better performance and is selected to be the prediction algorithm implemented for the cellphone application. Two applications have been designed on top of the prediction algorithm: one predicts the expected available energy at the station and the other one predicts the expected charging finishing time. The total time, including accessing the database, data processing, and prediction is about one second for both applications.

  10. 47 CFR 1.1107 - Schedule of charges for applications and other filings for the international services. (United States)


    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Schedule of charges for applications and other... Schedule of charges for applications and other filings for the international services. Remit manual filings... Stations: a. Initial Application (per station) 312 Main & Schedule B & 159 2,530.00 BAX b. Modification of...

  11. Effects of Particle Surface Charge, Species, Concentration, and Dispersion Method on the Thermal Conductivity of Nanofluids

    Directory of Open Access Journals (Sweden)

    Raghu Gowda


    Full Text Available The purpose of this experimental study is to evaluate the effects of particle species, surface charge, concentration, preparation technique, and base fluid on thermal transport capability of nanoparticle suspensions (nanofluids. The surface charge was varied by changing the pH value of the fluids. The alumina (Al2O3 and copper oxide (CuO nanoparticles were dispersed in deionized (DI water and ethylene glycol (EG, respectively. The nanofluids were prepared using both bath-type and probe sonicator under different power inputs. The experimental results were compared with the available experimental data as well as the predicted values obtained from Maxwell effective medium theory. It was found that ethylene glycol is more suitable for nanofluids applications than DI water in terms of thermal conductivity improvement and stability of nanofluids. Surface charge can effectively improve the dispersion of nanoparticles by reducing the (aggregated particle size in base fluids. A nanofluid with high surface charge (low pH has a higher thermal conductivity for a similar particle concentration. The sonication also has a significant impact on thermal conductivity enhancement. All these results suggest that the key to the improvement of thermal conductivity of nanofluids is a uniform and stable dispersion of nanoscale particles in a fluid.

  12. Proximity effects in cold gases of multiply charged atoms (Review) (United States)

    Chikina, I.; Shikin, V.


    Possible proximity effects in gases of cold, multiply charged atoms are discussed. Here we deal with rarefied gases with densities nd of multiply charged (Z ≫ 1) atoms at low temperatures in the well-known Thomas-Fermi (TF) approximation, which can be used to evaluate the statistical properties of single atoms. In order to retain the advantages of the TF formalism, which is successful for symmetric problems, the external boundary conditions accounting for the finiteness of the density of atoms (donors), nd ≠ 0, are also symmetrized (using a spherical Wigner-Seitz cell) and formulated in a standard way that conserves the total charge within the cell. The model shows that at zero temperature in a rarefied gas of multiply charged atoms there is an effective long-range interaction Eproxi(nd), the sign of which depends on the properties of the outer shells of individual atoms. The long-range character of the interaction Eproxi is evaluated by comparing it with the properties of the well-known London dispersive attraction ELond(nd) 0 and for the alkali and alkaline-earth elements Eproxi theory through the temperature dependence of the different versions of Eproxi. The anomaly in the thermal proximity effect shows up in the following way: for T ≠ 0 there is no equilibrium solution of TS statistics for single multiply charged atoms in a vacuum when the effect is present. Instability is suppressed in a Wigner-Seitz model under the assumption that there are no electron fluxes through the outer boundary R3 ∝ n-1d of a Wigner-Seitz cell. Eproxi corresponds to the definition of the correlation energy in a gas of interacting particles. This review is written so as to enable comparison of the results of the TF formalism with the standard assumptions of the correlation theory for classical plasmas. The classic example from work on weak solutions (including charged solutions)—the use of semi-impermeable membranes for studies of osmotic pressure—is highly appropriate for

  13. Space-charge effects in high-energy photoemission

    Energy Technology Data Exchange (ETDEWEB)

    Verna, Adriano, E-mail: [Dipartimento di Scienze, Università degli Studi Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy); CNISM Unità di Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy); Greco, Giorgia [Dipartimento di Scienze, Università degli Studi Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy); Lollobrigida, Valerio [Dipartimento di Scienze, Università degli Studi Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy); Scuola Dottorale in Matematica e Fisica, Università Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy); Offi, Francesco; Stefani, Giovanni [Dipartimento di Scienze, Università degli Studi Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy); CNISM Unità di Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy)


    Highlights: • N-body simulations of interacting photoelectrons in hard X-ray experiments. • Secondary electrons have a pivotal role in determining the energy broadening. • Space charge has negligible effects on the photoelectron momentum distribution. • A simple model provides the characteristic time for energy-broadening mechanism. • The feasibility of time-resolved high-energy experiments with FELs is discussed. - Abstract: Pump-and-probe photoelectron spectroscopy (PES) with femtosecond pulsed sources opens new perspectives in the investigation of the ultrafast dynamics of physical and chemical processes at the surfaces and interfaces of solids. Nevertheless, for very intense photon pulses a large number of photoelectrons are simultaneously emitted and their mutual Coulomb repulsion is sufficiently strong to significantly modify their trajectory and kinetic energy. This phenomenon, referred as space-charge effect, determines a broadening and shift in energy for the typical PES structures and a dramatic loss of energy resolution. In this article we examine the effects of space charge in PES with a particular focus on time-resolved hard X-ray (∼10 keV) experiments. The trajectory of the electrons photoemitted from pure Cu in a hard X-ray PES experiment has been reproduced through N-body simulations and the broadening of the photoemission core-level peaks has been monitored as a function of various parameters (photons per pulse, linear dimension of the photon spot, photon energy). The energy broadening results directly proportional to the number N of electrons emitted per pulse (mainly represented by secondary electrons) and inversely proportional to the linear dimension a of the photon spot on the sample surface, in agreement with the literature data about ultraviolet and soft X-ray experiments. The evolution in time of the energy broadening during the flight of the photoelectrons is also studied. Despite its detrimental consequences on the energy

  14. Fractal analysis of electroviscous effect in charged porous media (United States)

    Liang, Mingchao; Yang, Shanshan; Cui, Xiaomin; Li, Yongfeng


    An electroviscous effect is an important phenomenon making flow resistance larger in electrically charged capillaries or porous media. Thus, the study of this phenomenon is very meaningful in various scientific and engineering fields. In this work, based on the fractal characteristics of porous media, a theoretical apparent viscosity model is expressed in terms of the solid surface zeta potential, physical properties (viscosity, dielectric constant, and conductivity) of the electrolyte solution, maximum pore radius, pore fractal dimension, and tortuosity fractal dimension of porous media. A reasonably good match is found between the results from the fractal model and the available experimental data reported in the literature.

  15. Charging of heated colloidal particles using the electrolyte Seebeck effect. (United States)

    Majee, Arghya; Würger, Alois


    We propose a novel actuation mechanism for colloids, which is based on the Seebeck effect of the electrolyte solution: Laser heating of a nonionic particle accumulates in its vicinity a net charge Q, which is proportional to the excess temperature at the particle surface. The corresponding long-range thermoelectric field E is proportional to 1/r(2) provides a tool for controlled interactions with nearby beads or with additional molecular solutes. An external field E(ext) drags the thermocharged particle at a velocity that depends on its size and absorption properties; the latter point could be particularly relevant for separating carbon nanotubes according to their electronic band structure.

  16. Web Application in Online Pulsa Charging Using Macromedia Dreamweaver Mx


    Budi Prayitno


    Internet is now a become a most effective option in disseminating information, because the Internet has a range of very large networks. One of the information received great places on the Internet include information relating to the world of communication, especially in the field of credit sales business on-line. This information is conveyed through one of the storage media of information on the Internet Web site. Developed countries in Europe to implement cellular communication technology in...

  17. Ultrafast photoelectron spectroscopy of solutions: space-charge effect (United States)

    Al-Obaidi, R.; Wilke, M.; Borgwardt, M.; Metje, J.; Moguilevski, A.; Engel, N.; Tolksdorf, D.; Raheem, A.; Kampen, T.; Mähl, S.; Kiyan, I. Yu; Aziz, E. F.


    The method of time-resolved XUV photoelectron spectroscopy is applied in a pump-probe experiment on a liquid micro-jet. We investigate how the XUV energy spectra of photoelectrons are influenced by the space charge created due to ionization of the liquid medium by the pump laser pulse. XUV light from high-order harmonic generation is used to probe the electron population of the valence shell of iron hexacyanide in water. By exposing the sample to a short UV pump pulse of 266 nm wavelength and ˜55 fs duration, we observe an energy shift of the spectral component associated with XUV ionization from the Fe 3d(t2g) orbital as well as a shift of the water spectrum. Depending on the sequence of the pump and probe pulses, the arising energy shift of photoelectrons acquires a positive or negative value. It exhibits a sharp positive peak at small time delays, which facilitates to determine the temporal overlap between pump and probe pulses. The negative spectral shift is due to positive charge accumulated in the liquid medium during ionization. Its dissipation is found to occur on a (sub)nanosecond time scale and has a biexponential character. A simple mean-field model is provided to interpret the observations. A comparison between the intensity dependencies of the spectral shift and the UV ionization yield shows that the space-charge effect can be significantly reduced when the pump intensity is attenuated below the saturation level of water ionization. For the given experimental conditions, the saturation intensity lies at 6× {10}10 W cm-2.

  18. Charging and plasma effects under ultrashort pulsed laser ablation (United States)

    Bulgakova, N. M.; Bulgakov, A. V.; Zhukov, V. P.; Marine, W.; Vorobyev, A. Y.; Guo, Chunlei


    Based on experiments and a theoretical analysis, we raise questions on two fundamental mechanisms of femtosecond laser desorption/ablation of solids, namely Coulomb explosion (CE) and plasma etching. The effects of laser-induced ionization and surface charging are analyzed which can be responsible for ultrafast ions observed in time-of-flight mass-spectra under ultrashort laser irradiation of solids. The importance of surface charging in formation of velocity distributions of desorbed/ablated species has been revealed for conditions when the CE mechanism is inhibited. The influence of ambient plasma formation on the dynamics of heating of metallic targets by femtosecond laser pulses is studied based on 2D modeling of laser-induced target heating and dynamics of the ambient plasma. The calculations show an intriguing picture of the laser-induced ambient gas motion. We propose a model of laser-induced breakdown of an ambient gas in a region in front of the irradiated target and analyze plasma-chemical processes which can affect laser processing of surfaces in the presence of air or highly reactive media.

  19. Non-equilibration of topological charge and its effects

    CERN Document Server

    Bernard, Claude


    In QCD simulations at small lattice spacings, the topological charge Q evolves very slowly and, if this quantity is not properly equilibrated, we could get incorrect results for physical quantities, or incorrect estimates of their errors. We use the known relation between the dependence of masses and decay constants on the QCD vacuum angle theta and the squared topological charge Q^2 together with chiral perturbation theory results for the dependence of masses and decay constants on theta to estimate the size of these effects and suggest strategies for dealing with them. For the partially quenched case, we sketch an alternative derivation of the known $\\chi$PT results of Aoki and Fukaya, using the nonperturbatively correct chiral theory worked out by Golterman, Sharpe and Singleton, and by Sharpe and Shoresh. With the MILC collaboration's ensembles of lattices with four flavors of HISQ dynamical quarks, we measure the $Q^2$ dependence of masses and decay constants and compare to the $\\chi$PT forms. The observ...

  20. Interactions of human hemoglobin with charged ligand-functionalized iron oxide nanoparticles and effect of counterions

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Goutam, E-mail: [UGC-DAE Consortium for Scientific Research, Mumbai Centre (India); Panicker, Lata [Bhabha Atomic Research Centre, Solid State Physics Division (India)


    Human hemoglobin is an important metalloprotein. It has tetrameric structure with each subunit containing a ‘heme’ group which carries oxygen and carbon dioxide in blood. In this work, we have investigated the interactions of human hemoglobin (Hb) with charged ligand-functionalized iron oxide nanoparticles and the effect of counterions, in aqueous medium. Several techniques like DLS and ζ-potential measurements, UV–vis, fluorescence, and CD spectroscopy have been used to characterize the interaction. The nanoparticle size was measured to be in the range of 20–30 nm. Our results indicated the binding of Hb with both positively as well as negatively charged ligand-functionalized iron oxide nanoparticles in neutral aqueous medium which was driven by the electrostatic and the hydrophobic interactions. The electrostatic binding interaction was not seen in phosphate buffer at pH 7.4. We have also observed that the ‘heme’ groups of Hb remained unaffected on binding with charged nanoparticles, suggesting the utility of the charged ligand-functionalized nanoparticles in biomedical applications.

  1. Reversed Hall effect and plasma conductivity in the presence of charged impurities (United States)

    Yaroshenko, V. V.; Lühr, H.


    The Hall conductivity of magnetized plasma can be strongly suppressed by the contribution of negatively charged particulates (referred further as "dust"). Once the charge density accumulated by the dust exceeds a certain threshold, the Hall component becomes negative, providing a reversal in the Hall current. Such an effect is unique for dust-loaded plasmas, and it can hardly be achieved in electronegative plasmas. Further growth of the dust density leads to an increase in both the absolute value of the Hall and Pedersen conductivities, while the field-aligned component is decreased. These modifications enhance the role of transverse electric currents and reduce the anisotropy of a magnetized plasma when loaded with charged impurities. The findings provide an important basis for studying the generation of electric currents and transport phenomena in magnetized plasma systems containing small charged particulates. They can be relevant for a wide range of applications from naturally occurring space plasmas in planetary magnetospheres and astrophysical objects to laboratory dusty plasmas (Magnetized Dusty Plasma Experiment) and to technological and fusion plasmas.

  2. Embedding effects on charge-transport parameters in molecular organic materials. (United States)

    Lipparini, Filippo; Mennucci, Benedetta


    We present a generalized version of the tight-binding approach to determine the electronic coupling parameter in charge (hole) transport phenomena in organic materials. The main novelty of this approach is that the "embedding effects" of the environment (either a solvent or a crystal packing) can be explicitly included in the calculation by considering an embedded dimer. One of the main features shown by the application of the method to both model systems and oligoacene crystals is that the routinely used "energy splitting in a dimer" approximation gives reasonable results even if the transfer units are not equivalent by symmetry but the embedding effects are properly taken into account.

  3. Embedding effects on charge-transport parameters in molecular organic materials (United States)

    Lipparini, Filippo; Mennucci, Benedetta


    We present a generalized version of the tight-binding approach to determine the electronic coupling parameter in charge (hole) transport phenomena in organic materials. The main novelty of this approach is that the "embedding effects" of the environment (either a solvent or a crystal packing) can be explicitly included in the calculation by considering an embedded dimer. One of the main features shown by the application of the method to both model systems and oligoacene crystals is that the routinely used "energy splitting in a dimer" approximation gives reasonable results even if the transfer units are not equivalent by symmetry but the embedding effects are properly taken into account.

  4. Charge Transfer and Support Effects in Heterogeneous Catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Hervier, Antoine [Univ. of California, Berkeley, CA (United States)


    the band bending at the interface, gives rise to a steady-state flow of hot holes to the surface. This leads to a decrease in turnover on the surface, an effect which is enhanced when a reverse bias is applied to the diode. Similar experiments were carried out for CO oxidation. On Pt/Si diodes, the reaction rate was found to increase when a forward bias was applied. When the diode was exposed to visible light and a reverse bias was applied, the rate was instead decreased. This implies that a flow of negative charges to the surface increases turnover, while positive charges decrease it. Charge flow in an oxide supported metal catalyst can be modified even without designing the catalyst as a solid state electronic device. This was done by doping stoichiometric and nonstoichiometric TiO2 films with F, and using the resulting oxides as supports for Pt films. In the case of stoichiometric TiO2, F was found to act as an n-type dopant, creating a population of filled electronic states just below the conduction band, and dramatically increasing the conductivity of the oxide film. The electrons in those states can transfer to surface O, activating it for reaction with CO, and leading to increased turnover for CO oxidation. This reinforces the hypothesis that CO oxidation is activated by a flow of negative charges to the surface. The same set of catalysts was used for methanol oxidation. The electronic properties of the TiO2 films again correlated with the turnover rates, but also with selectivity. With stoichiometric TiO2 as the support, F-doping caused an increase in selectivity toward the formation of partial oxidation products, formaldehyde and methyl formate, versus the total oxidation product, CO2. With non-stoichiometric TiO2, F-doping had the reverse effect. Ambient Pressure X-Ray Photoelectron Spectroscopy was used to investigate this F-doping effect in reaction conditions. In O2 alone, and in

  5. Polyelectrolyte assisted charge titration spectrometry: Applications to latex and oxide nanoparticles. (United States)

    Mousseau, F; Vitorazi, L; Herrmann, L; Mornet, S; Berret, J-F


    The electrostatic charge density of particles is of paramount importance for the control of the dispersion stability. Conventional methods use potentiometric, conductometric or turbidity titration but require large amount of samples. Here we report a simple and cost-effective method called polyelectrolyte assisted charge titration spectrometry or PACTS. The technique takes advantage of the propensity of oppositely charged polymers and particles to assemble upon mixing, leading to aggregation or phase separation. The mixed dispersions exhibit a maximum in light scattering as a function of the volumetric ratio X, and the peak position XMax is linked to the particle charge density according to σ∼D0XMax where D0 is the particle diameter. The PACTS is successfully applied to organic latex, aluminum and silicon oxide particles of positive or negative charge using poly(diallyldimethylammonium chloride) and poly(sodium 4-styrenesulfonate). The protocol is also optimized with respect to important parameters such as pH and concentration, and to the polyelectrolyte molecular weight. The advantages of the PACTS technique are that it requires minute amounts of sample and that it is suitable to a broad variety of charged nano-objects. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Charging of small grains in a space plasma: Application to Jovian stream particles (United States)

    Dzhanoev, A. R.; Schmidt, J.; Liu, X.; Spahn, F.


    Context. Most theoretical investigations of dust charging processes in space have treated the current balance condition as independent of grain size. However, for small grains, since they are often observed in space environments, a dependence on grain size is expected owing to secondary electron emission (SEE). Here, by the term "small" we mean a particle size comparable to the typical penetration depth for given primary electron energy. The results are relevant for the dynamics of small, charged dust particles emitted by the volcanic moon Io, which forms the Jovian dust streams. Aims: We revise the theory of charging of small (submicron sized) micrometeoroids to take into account a high production of secondary electrons for small grains immersed in an isotropic flux of electrons. We apply our model to obtain an improved estimate for the charge of the dust streams leaving the Jovian system, detected by several spacecraft. Methods: We apply a continuum model to describe the penetration of primary electrons in a grain and the emission of secondary electrons along the path. Averaging over an isotropic flux of primaries, we derive a new expression for the secondary electron yield, which can be used to express the secondary electron current on a grain. Results: For the Jupiter plasma environment we derive the surface potential of grains composed of NaCl (believed to be the major constituent of Jovian dust stream particles) or silicates. For small particles, the potential depends on grain size and the secondary electron current induces a sensitivity to material properties. As a result of the small particle effect, the estimates for the charging times and for the fractional charge fluctuations of NaCl grains obtained using our general approach to SEE give results qualitatively different from the analogous estimates derived from the traditional approach to SEE. We find that for the charging environment considered in this paper field emission does not limit the charging of

  7. Modification of reduced-charge montmorillonites by a series of Gemini surfactants: Characterization and application in methyl orange removal (United States)

    Luo, Zhongxin; Gao, Manglai; Ye, Yage; Yang, Senfeng


    The influences that the spacer chain length of Gemini surfactants and clay layer charge have on the structures and sorption characteristics of organoclays have been investigated. Organoclays were obtained by modifying a series of reduced charge montmorillonites (RCMs) using three Gemini surfactants with different spacer length. And their structures and sorption characteristics for methyl orange (MO) were examined. It was suggested that the amount, spacer length of Gemini surfactant and clay layer charge had significant effects on the microstructure of the organoclays. The adsorption experiments results claimed that the uptake of MO onto organoclays was in the order: 16-4-16-Mt > 16-8-16-Mt > 16-6-16-Mt, while it increased with increasing clay layer charge. The adsorption isotherms of MO onto the organoclays could be best described by Langmuir equation, and the adsorption kinetic was in good agreement with the pseudo-second-order model. Thermodynamic parameters demonstrated that the sorption process was spontaneous and endothermic in nature. This work will provide a deep insight into the interaction of Gemini-modified clays and MO, which pave the way for their practical applications in anionic dye adsorption.

  8. The Effect of Superparamagnetic Iron Oxide Nanoparticle Surface Charge on Antigen Cross-Presentation (United States)

    Mou, Yongbin; Xing, Yun; Ren, Hongyan; Cui, Zhihua; Zhang, Yu; Yu, Guangjie; Urba, Walter J.; Hu, Qingang; Hu, Hongming


    Magnetic nanoparticles (NPs) of superparamagnetic iron oxide (SPIO) have been explored for different kinds of applications in biomedicine, mechanics, and information. Here, we explored the synthetic SPIO NPs as an adjuvant on antigen cross-presentation ability by enhancing the intracellular delivery of antigens into antigen presenting cells (APCs). Particles with different chemical modifications and surface charges were used to study the mechanism of action of antigen delivery. Specifically, two types of magnetic NPs, γFe2O3/APTS (3-aminopropyltrimethoxysilane) NPs and γFe2O3/DMSA (meso-2, 3-Dimercaptosuccinic acid) NPs, with the same crystal structure, magnetic properties, and size distribution were prepared. Then, the promotion of T-cell activation via dendritic cells (DCs) was compared among different charged antigen coated NPs. Moreover, the activation of the autophagy, cytosolic delivery of the antigens, and antigen degradation mediated by the proteasome and lysosome were measured. Our results indicated that positive charged γFe2O3/APTS NPs, but not negative charged γFe2O3/DMSA NPs, enhanced the cross-presentation ability of DCs. Increased cross-presentation ability induced by γFe2O3/APTS NPs was associated with increased cytosolic antigen delivery. On the contrary, γFe2O3/DMSA NPs was associated with rapid autophagy. Overall, our results suggest that antigen delivered in cytoplasm induced by positive charged particles is beneficial for antigen cross-presentation and T-cell activation. NPs modified with different chemistries exhibit diverse biological properties and differ greatly in their adjuvant potentials. Thus, it should be carefully considered many different effects of NPs to design effective and safe adjuvants.

  9. Nonvolatile memory with graphene oxide as a charge storage node in nanowire field-effect transistors (United States)

    Baek, David J.; Seol, Myeong-Lok; Choi, Sung-Jin; Moon, Dong-Il; Choi, Yang-Kyu


    Through the structural modification of a three-dimensional silicon nanowire field-effect transistor, i.e., a double-gate FinFET, a structural platform was developed which allowed for us to utilize graphene oxide (GO) as a charge trapping layer in a nonvolatile memory device. By creating a nanogap between the gate and the channel, GO was embedded after the complete device fabrication. By applying a proper gate voltage, charge trapping, and de-trapping within the GO was enabled and resulted in large threshold voltage shifts. The employment of GO with FinFET in our work suggests that graphitic materials can potentially play a significant role for future nanoelectronic applications.

  10. Distinguishing Field Effects from Charge Effects in the Optoelectronic Properties of Carbon Nanotube Films

    Directory of Open Access Journals (Sweden)

    W. Joshua Kennedy


    Full Text Available We have used charge-induced absorption to quantify the influence of injected charges on electroabsorption measurements in single-wall carbon nanotube films. The interpretations of experimental measurements of χ3 processes in nanotubes are simplified by taking into account the change in electron-electron interactions upon charge injection. Electroabsorption spectra that are properly corrected for charge-induced effects show remarkable agreement with a simple Stark shift of the exciton transitions with no notable second-derivative contributions. Thus, distinguishing electric field effects from carrier density effects allows for a more rigorous calculation of exciton polarizability from electroabsorption measurements, even in heterogeneous films. PACS: 78.67.Ch Nanotubes: optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures.

  11. The effect of surface charge on the boundary slip of various oleophilic/phobic surfaces immersed in liquids. (United States)

    Li, Yifan; Bhushan, Bharat


    The reduction of fluid drag is an important issue in many fluid flow applications at the micro/nanoscale. Boundary slip is believed to affect fluid drag. Slip length has been measured on various surfaces with different degrees of hydrophobicity and oleophobicity immersed in various liquids of scientific interest. Surface charge has been found to affect slip length in water and electrolytes. However, there are no studies on the effect of surface charge on slip at solid-oil interfaces. This study focuses on the effect of surface charge on the boundary slip of superoleophilic, oleophilic, oleophobic, and superoleophobic surfaces immersed in deionized (DI) water and hexadecane and ethylene glycol, based on atomic force microscopy (AFM). The surface charge was changed by applying a positive electric field to the solid-liquid interface, and by using liquids with different pH values. The results show that slip length increases with an increase in applied positive electric field voltage. Slip length also increases with a decrease in the pH of the solutions. The change in slip length is dependent on the absolute value of the surface charge, and a larger surface charge density results in a smaller slip length. In addition, the surface charge density at different solid-liquid interfaces is related to the dielectric properties of the surface. The underlying mechanisms are analyzed.

  12. Effect of Negatively Charged Impurity on Graphene Magnetic Rings (United States)

    Lee, Chak Man; Sum Chan, Kwok; Ho, Johnny Chung Yin


    Using the massless Dirac-Weyl model of monolayer graphene, we study the effect of a negatively charged Coulomb impurity on the low-lying spectra of single-electron magnetic dot and ring systems. The numerical results show that the electron-hole symmetry in the spectra is broken by the Coulomb potential, and the original degenerate energy level lying at zero energy becomes nondegenerate and splits into infinite discrete angular momentum states, which have positive energies and thus are electron-like. For higher LLs, each has a reverse ordering of the energy levels when r022/a2 is larger than its critical value in the positive energy states for magnetic dot systems owing to the competition between the Coulomb potential and the magnetic confinement.

  13. Effects of Polyelectrolyte Microcapsules with Different Surface Charge on Erythrocyte Sedimentation Rate. (United States)

    Naumov, A A; Dubrovskii, A V; Potselueva, M M; Tikhonenko, S A


    Relationship between changes in the erythrocyte sedimentation rate in rats and concentration and charge of polyelectrolyte microcapsules was studied by the Panchenkov method. Positively charged microcapsules reduced erythrocyte sedimentation rate in a concentrationdependent manner. This effect was related to a decrease in the content of high-molecularweight proteins in the plasma due to their adsorption in positively charged microcapsules with polyacrylamide surface layer.

  14. Charge diffusion and the butterfly effect in striped holographic matter

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, Andrew [Department of Physics, Harvard University,Cambridge, MA 02138 (United States); Department of Physics, Stanford University,Stanford, CA 94305 (United States); Steinberg, Julia [Department of Physics, Harvard University,Cambridge, MA 02138 (United States)


    Recently, it has been proposed that the butterfly velocity — a speed at which quantum information propagates — may provide a fundamental bound on diffusion constants in dirty incoherent metals. We analytically compute the charge diffusion constant and the butterfly velocity in charge-neutral holographic matter with long wavelength “hydrodynamic' disorder in a single spatial direction. In this limit, we find that the butterfly velocity does not set a sharp lower bound for the charge diffusion constant.

  15. Charge diffusion and the butterfly effect in striped holographic matter (United States)

    Lucas, Andrew; Steinberg, Julia


    Recently, it has been proposed that the butterfly velocity — a speed at which quantum information propagates — may provide a fundamental bound on diffusion constants in dirty incoherent metals. We analytically compute the charge diffusion constant and the butterfly velocity in charge-neutral holographic matter with long wavelength "hydrodynamic" disorder in a single spatial direction. In this limit, we find that the butterfly velocity does not set a sharp lower bound for the charge diffusion constant.

  16. Charge-imaging field-effect transistors for scanned probe microscopy (United States)

    Chen, Lester Hao-Lin

    This thesis presents experiments on integrating a charge-imaging field-effect transistor onto a scanned probe microscopy cantilever to make a moveable charge-imager. Such an imager would be used for imaging the spatial distribution of electric charge in semiconductor heterostructures and devices. Learning about the spatial distribution of charge yields knowledge about electrical transport at the microscopic level. The information gained from measuring the spatial distribution of charge increases with improvements in the spatial resolution and charge sensitivity of the charge-imaging probes. So, the goal is to devise a charge-imager with sub-micron spatial resolution and single-electron charge sensitivity. To achieve high spatial resolution and excellent charge sensitivity, the charge-imaging field-effect transistors are made with a quantum point contact geometry. The charge response is confined to a disc with full width half-maximum comparable to its channel width, and the charge noise spectrum reaches values "1 e/Hz½ at 30 kHz. Their low power dissipation (deflections of the cantilever to map the sample topography. The strain-sensing field-effect transistors have a white noise value for the deflection noise of 0.5 nm/Hz½ at 10 kHz. This thesis describes the fabrication and characterization of charge-imaging field-effect transistors and scanned microscopy cantilevers with integrated strain-sensing transistors. The transistors and cantilevers were fabricated in a GaAs/AlGaAs heterostructure using electron-beam lithography and were characterized at liquid Helium temperatures. Possible future experiments include demonstrating the charge-imaging FET's sensitivity to single electrons, creating a charge- and topography-imaging cantilever, and directly measuring the electron distributions in nanostructures.

  17. Integration of ammonia-plasma-functionalized graphene nanodiscs as charge trapping centers for nonvolatile memory applications

    KAUST Repository

    Wang, Jer-Chyi


    Graphene nanodiscs (GNDs), functionalized using NH3 plasma, as charge trapping sites (CTSs) for non-volatile memory applications have been investigated in this study. The fabrication process relies on the patterning of Au nanoparticles (Au-NPs), whose thicknesses are tuned to adjust the GND density and size upon etching. A GND density as high as 8 × 1011 cm−2 and a diameter of approximately 20 nm are achieved. The functionalization of GNDs by NH3 plasma creates Nsingle bondH+ functional groups that act as CTSs, as observed by Raman and Fourier transform infrared spectroscopy. This inherently enhances the density of CTSs in the GNDs, as a result, the memory window becomes more than 2.4 V and remains stable after 104 operating cycles. The charge loss is less than 10% for a 10-year data retention testing, making this low-temperature process suitable for low-cost non-volatile memory applications on flexible substrates.

  18. Mass and charge conservation check in dynamic models: application to the new ADM1 model. (United States)

    de Gracia, M; Sancho, L; García-Heras, J L; Vanrolleghem, P; Ayesa, E


    This paper proposes a systematic methodology for the analysis of the mass and charge balances in dynamic models expressed using the Petersen matrix notation. This methodology is based on the definition of the model components via elemental mass fractions and in the estimation of the COD as a function of the redox equations associated with these elements. This approach makes the automatic calculation of all the stoichiometric coefficients under different measuring units and the study of COD, charge or mass fluxes easier. As an example of its application this methodology was applied to the ADM1 in order to illustrate its usefulness for the analysis of organic matter characterisation, nitrogen release or biogas composition in anaerobic digestion. The application of the methodology for a rigorous integration of different IWA models is proposed for further study.

  19. Voltage-Dependent Charge Storage in Cladded Zn0.56Cd0.44Se Quantum Dot MOS Capacitors for Multibit Memory Applications (United States)

    Khan, J.; Lingalugari, M.; Al-Amoody, F.; Jain, F.


    As conventional memories approach scaling limitations, new storage methods must be utilized to increase Si yield and produce higher on-chip memory density. Use of II-VI Zn0.56Cd0.44Se quantum dots (QDs) is compatible with epitaxial gate insulators such as ZnS-ZnMgS. Voltage-dependent charging effects in cladded Zn0.56Cd0.44Se QDs are presented in a conventional metal-oxide-semiconductor capacitor structure. Charge storage capabilities in Si and ZnMgS QDs have been reported by various researchers; this work is focused on II-VI material Zn0.56Cd0.44Se QDs nucleated using photoassisted microwave plasma metalorganic chemical vapor deposition. Using capacitance-voltage hysteresis characterization, the multistep charging and discharging capabilities of the QDs at room temperature are presented. Three charging states are presented within a 10 V charging voltage range. These characteristics exemplify discrete charge states in the QD layer, perfect for multibit, QD-functionalized high-density memory applications. Multiple charge states with low operating voltage provide device characteristics that can be used for multibit storage by allowing varying charges to be stored in a QD layer based on the applied "write" voltage.

  20. Kinetic Spraying Deposition of Reactive-Enhanced Al-Ni Composite for Shaped Charge Liner Applications (United States)

    Byun, Gyeongjun; Kim, Jaeick; Lee, Changhee; Kim, See Jo; Lee, Seong


    Liners used in shaped charges (SC) must possess good penetration ability and explosive power. Producing the reactive layer (i.e., the Al-Ni composite) on a well-penetrating liner (i.e., Cu) via spray coating is a novel method; the exothermic reaction of this reactive layer can be enhanced by controlling the structure of the feedstock material. However, preceding studies have been unable to completely succeed in achieving this goal. There is still an opportunity to improve the performance of reactive layers in SC liner applications. In order to address this problem, a reactive Al-Ni composite powder was produced via arrested reactive milling (ARM) and deposited by a kinetic spray process. Afterward, the deposition state and self-propagating high-temperature synthesis (SHS) reaction behavior of the ARMed Al-Ni deposit were investigated. The deposition state was degraded by the ARM process due to the remaining solid lubricant and the strain-hardening effect, but the practically estimated bond strength was not poor (~40 MPa). No SHS reactions were induced by the ARM and kinetic spray process, which resulted in the quantitative maximization of the exothermic reaction. It is noteworthy that the initiation temperature of the SHS reaction was highly advanced (~300 °C) relative to preceding studies (~500 °C); this change is due to the additional mechanical activation initiated by the kinetic spray deposition.

  1. Space-charge effects in ultrahigh current electron bunches generated by laser-plasma accelerators

    Directory of Open Access Journals (Sweden)

    F. J. Grüner


    Full Text Available Recent advances in laser-plasma accelerators, including the generation of GeV-scale electron bunches, enable applications such as driving a compact free-electron laser (FEL. Significant reduction in size of the FEL is facilitated by the expected ultrahigh peak beam currents (10–100 kA generated in laser-plasma accelerators. At low electron energies such peak currents are expected to cause space-charge effects such as bunch expansion and induced energy variations along the bunch, potentially hindering the FEL process. In this paper we discuss a self-consistent approach to modeling space-charge effects for the regime of laser-plasma-accelerated ultracompact electron bunches at low or moderate energies. Analytical treatments are considered as well as point-to-point particle simulations, including the beam transport from the laser-plasma accelerator through focusing devices and the undulator. In contradiction to non-self-consistent analyses (i.e., neglecting bunch evolution, which predict a linearly growing energy chirp, we have found the energy chirp reaches a maximum and decreases thereafter. The impact of the space-charge induced chirp on FEL performance is discussed and possible solutions are presented.

  2. Transport, charge exchange and loss of energetic heavy ions in the earth's radiation belts - Applicability and limitations of theory (United States)

    Spjeldvik, W. N.


    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.

  3. Analytical estimation of effective charges at saturation in Poisson-Boltzmann cell models

    CERN Document Server

    Trizac, E; Bocquet, L


    We propose a simple approximation scheme for computing the effective charges of highly charged colloids (spherical or cylindrical with infinite length). Within non-linear Poisson-Boltzmann theory, we start from an expression for the effective charge in the infinite-dilution limit which is asymptotically valid for large salt concentrations; this result is then extended to finite colloidal concentration, approximating the salt partitioning effect which relates the salt content in the suspension to that of a dialysing reservoir. This leads to an analytical expression for the effective charge as a function of colloid volume fraction and salt concentration. These results compare favourably with the effective charges at saturation (i.e. in the limit of large bare charge) computed numerically following the standard prescription proposed by Alexander et al within the cell model.

  4. The effect of temperature on charge movement repriming in amphibian skeletal muscle fibers. (United States)

    Gonzalez, A; Caputo, C


    Cut twitch muscle fibers, mounted in a triple Vaseline-gap chamber, were used to study the effects of temperature on intramembranous charge movement and, in particular, on the repriming of charge 1 (the intramembranous charge that normally moves in the potential range between -100 and +40 mV). Changing the holding potential from -90 to 0 mV modified the voltage distribution of charge movement but not the maximum movable charge. Temperature changes between 16 and 5 degrees C did not modify the fiber linear capacitance, the maximum nonlinear intramembranous charge, or the voltage distribution of charge 1 and charge 2 (the intramembranous charge moving in the membrane potential range between approximately -4 and -160 mV). We used a pulse protocol designed to study the repriming time course of charge 1, with little contamination from charge 2. The time course of charge movement repriming at 15 degrees C is described by a double exponential with time constants of 4.2 and 25 s. Repriming kinetics were found to be highly temperature dependent, with two rate-limiting steps having Q10 (increase in rate of a process by raising temperature 10 degrees C) values of 1.7 and 7.1 above and below 11.5 degrees C, respectively. This is characteristic of processes with a high energy of activation and could be associated with a conformational change of the voltage sensor or with the interaction between the voltage sensor and the calcium release channel.

  5. Importance of polaron effects for charge carrier mobility above and ...

    Indian Academy of Sciences (India)

    HTSCs) have been investigated theoretically. The appropriate Boltzmann transport equations under relaxation time approximation were used to calculate the mobility of polaronic charge carriers and bosonic Cooper pairs above and below the ...

  6. Intramolecular charge transfer effects on 3-aminobenzoic acid

    Energy Technology Data Exchange (ETDEWEB)

    Stalin, T. [Department of Chemistry, Annamalai University, Annamalainagar, Chidambaram 608 002, Tamil Nadu (India); Rajendiran, N. [Department of Chemistry, Annamalai University, Annamalainagar, Chidambaram 608 002, Tamil Nadu (India)], E-mail:


    Effect of solvents, buffer solutions of different pH and {beta}-cyclodextrin on the absorption and fluorescence spectra of 3-aminobenzoic acid (3ABA) have been investigated. The solid inclusion complex of 3ABA with {beta}-CD is discussed by UV-Vis, fluorimetry, semiempirical quantum calculations (AM1), FT-IR, {sup 1}H NMR and Scanning Electron Microscope (SEM). The thermodynamic parameters ({delta}H, {delta}G and {delta}S) of the inclusion process are also determined. The experimental results indicated that the inclusion processes is an exothermic and spontaneous. The large Stokes shift emission in solvents with 3ABA are correlated with different solvent polarity scales suggest that, 3ABA molecule is more polar in the S{sub 1} state. Solvent, {beta}-CD studies and excited state dipole moment values confirms that the presence of intramolecular charge transfer (ICT) in 3ABA. Acidity constants for different prototropic equilibria of 3ABA in the S{sub 0} and S{sub 1} states are calculated. {beta}-Cyclodextrin studies shows that 3ABA forms a 1:1 inclusion complex with {beta}-CD. {beta}-CD studies suggest COOH group present in non-polar part and amino group present in hydrophilic part of the {beta}-CD cavity. A mechanism is proposed to explain the inclusion process.

  7. Effect of charging on silicene with alkali metal atom adsorption (United States)

    Li, Manman; Li, Zhongyao; Gong, Shi-Jing


    Based on first-principles calculations, we studied the effects of charging on the structure, binding energy and electronic properties of silicene with alkali metal (AM) atom (Li, Na or K) adsorption. In AMSi2, electron doping enlarges the lattice constant of silicene, while the influence of hole doping is non-monotonic. In AMSi8, the lattice constant increases/decreases almost linearly with the increase in electron/hole doping. In addition, the AM–Si vertical distance can be greatly enlarged by excessive hole doping in both AMSi2 and AMSi8 systems. When the hole doping is as large as  +e per unit cell, both AMSi2 and AMSi8 can be transformed from metal to semiconductor. However, the binding energy would be negative in the AM+ Si2 semiconductor. It suggests AM+ Si2 is unstable in this case. In addition, the electron doping and the AM–Si vertical distance would greatly influence the band gap of silicene in LiSi8 and NaSi8, while the band gap in KSi8 is relatively stable. Therefore, KSi8 may be a more practicable material in nanotechnology.

  8. Mechano-chemical effects in weakly charged porous media. (United States)

    Zholkovskij, Emiliy K; Yaroshchuk, Andriy E; Koval'chuk, Volodymyr I; Bondarenko, Mykola P


    The paper is concerned with mechano-chemical effects, namely, osmosis and pressure-driven separation of ions that can be observed when a charged porous medium is placed between two electrolyte solutions. The study is focused on porous systems with low equilibrium interfacial potentials (about 30 mV or lower). At such low potentials, osmosis and pressure-driven separation of ions noticeably manifest themselves provided that the ions in the electrolyte solutions have different diffusion coefficients. The analysis is conducted by combining the irreversible thermodynamic approach and the linearized (in terms of the normalized equilibrium interfacial potential) version of the Standard Electrokinetic Model. Osmosis and the pressure-driven separation of ions are considered for an arbitrary mixed electrolyte solution and various porous space geometries. It is shown that the effects under consideration are proportional to a geometrical factor which, for all the considered geometries of porous space, can be expressed as a function of porosity and the Λ- parameter of porous medium normalized by the Debye length. For all the studied geometries, this function turns out to be weakly dependent on both the porosity and the geometry type. The latter allows for a rough evaluation of the geometrical factor from experimental data on electric conductivity and hydraulic permeability without previous knowledge of the porous space geometry. The obtained results are used to illustrate how the composition of electrolyte solution affects the mechano-chemical effects. For various examples of electrolyte solution compositions, the obtained results are capable of describing positive, negative and anomalous osmosis, positive and negative rejection of binary electrolytes, and pressure-driven separation of binary electrolyte mixtures. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Doping effect on photoabsorption and charge-separation dynamics in light-harvesting organic molecule

    Energy Technology Data Exchange (ETDEWEB)

    Ohmura, Satoshi, E-mail: [Research Center for Condensed Matter Physics, Department of Civil Engineering and Urban Design, Hiroshima Institute of Technology, Hiroshima 731-5193 (Japan); Tsuruta, Kenji [Department of Electrical and Electronic Engineering, Okayama University, Okayama 700-8530 (Japan); Shimojo, Fuyuki [Department of Physics, Kumamoto University, Kumamoto 860-8555 Japan (Japan); Nakano, Aiichiro [Collaboratory for Advanced Computing and Simulations, Department of Computer Science, Department of Physics & Astronomy, Department of Chemical Engineering & Materials Science, Department of Biological Sciences, University of Southern California, CA90089-024 (United States)


    Using ab-initio theoretical methods, we demonstrate possible enhancement of photo-conversion efficiency of an organic solar cell via intentional doping in molecular graphene-fullerene heterojunction [the hexabenzocoronene (HBC)-triethylene glycol (TEG)–C{sub 60} molecule]. Photoabsorption analysis indicates oxygen substitution into HBC leads to an extension of the spectra up to an infrared regime. A quantum-mechanical molecular dynamics simulation incorporating nonadiabatic electronic transitions reveals that a dissociated charge state (D{sup +} and A{sup -}) in the O-doped system is more stable than the pristine case due to the presence of an effective barrier by the TEG HOMO/LUMO level. We also find that oxygen doping in HBC enhances the intermolecular carrier mobility after charge separation. On the other hand, the pristine molecule undergoes rapid recombination between donor and acceptor charges at the interface. These analyses suggest that the graphene oxidation opens a new window in the application of organic super-molecules to solar cells.

  10. Space Charge Effects for the ERL Prototype Injector Line at Daresbury Laboratory

    CERN Document Server

    Muratori, Bruno; Owen, Hywel; de Loos, Marieke; van der Geer, Bas


    Daresbury Laboratory is currently building an Energy Recovery Linac Prototype (ERLP) that will operate at a beam energy of 35 MeV. In this paper we examine the space charge effects on the beam dynamics in the ERLP injector line. A Gaussian particle distribution is tracked with GPT (General Particle Tracer) through the injection line to the main linac to calculate the effect of 3Dspace charge in the dipoles. The nominal beam energy in the injection line is 8.3 MeV and the bunch charge 80 pC. The effects of space charge on the transverse and longitudinal emittance are studied for various electron beam parameter settings.

  11. Electronic Structure and Charge-Trapping Characteristics of the Al2O3-TiAlO-SiO2 Gate Stack for Nonvolatile Memory Applications. (United States)

    Xu, Wenchao; Zhang, Yang; Tang, Zhenjie; Shao, Zhengjie; Zhou, Guofu; Qin, Minghui; Zeng, Min; Wu, Sujuan; Zhang, Zhang; Gao, Jinwei; Lu, Xubing; Liu, Junming


    In this work, high-k composite TiAlO film has been investigated as charge-trapping material for nonvolatile memory applications. The annealing formed Al2O3-TiAlO-SiO2 dielectric stack demonstrates significant memory effects and excellent reliability properties. The memory device exhibits a large memory window of ~2.6 V under ±8 V sweeping voltage, and it shows only ~14% charge loss after more than 10 years' retention, indicating excellent charge retention properties. The electronic structures of the Al2O3-TiAlO-SiO2 have been studied by X-ray photoelectron spectroscopy measurements, and it reveals that the quantum well and the defect traps in TiAlO film can provide a >1.8 eV deep barrier for charge confinement in the TiAlO layer. The mixing between Al2O3 and TiO2 can increase the defects related to the under-coordinated Ti3+ atoms, thereby enhancing the charge-trapping efficiency of the device. Our work implies that high-k TiAlO composite film is promising for applications in future nonvolatile charge-trapping memories.

  12. Electronic Structure and Charge-Trapping Characteristics of the Al2O3-TiAlO-SiO2 Gate Stack for Nonvolatile Memory Applications (United States)

    Xu, Wenchao; Zhang, Yang; Tang, Zhenjie; Shao, Zhengjie; Zhou, Guofu; Qin, Minghui; Zeng, Min; Wu, Sujuan; Zhang, Zhang; Gao, Jinwei; Lu, Xubing; Liu, Junming


    In this work, high- k composite TiAlO film has been investigated as charge-trapping material for nonvolatile memory applications. The annealing formed Al2O3-TiAlO-SiO2 dielectric stack demonstrates significant memory effects and excellent reliability properties. The memory device exhibits a large memory window of 2.6 V under ±8 V sweeping voltage, and it shows only 14% charge loss after more than 10 years' retention, indicating excellent charge retention properties. The electronic structures of the Al2O3-TiAlO-SiO2 have been studied by X-ray photoelectron spectroscopy measurements, and it reveals that the quantum well and the defect traps in TiAlO film can provide a >1.8 eV deep barrier for charge confinement in the TiAlO layer. The mixing between Al2O3 and TiO2 can increase the defects related to the under-coordinated Ti3+ atoms, thereby enhancing the charge-trapping efficiency of the device. Our work implies that high- k TiAlO composite film is promising for applications in future nonvolatile charge-trapping memories.

  13. Effect of surfactant hydrophile-lipophile balance (HLB) value on mineral oxide charging in apolar media. (United States)

    Gacek, Matthew Michael; Berg, John C


    The current work examines the role of surfactant hydrophile-lipophile balance (HLB) on the ability for surfactant reverse micelles to impart charge to particles dispersed in an apolar medium, a study motivated by a number of applications that seek to maximize particle charge in such systems. Previous investigations have shown that relative acid-base properties of the particles and surfactants, as well as surfactant concentration and trace water content, all play a major role in the particle charge obtained. However, the ability of a surfactant to stabilize charge in reverse micelles is also an important aspect of creating charge on a particle surface. It has been previously shown that surfactant HLB value is an important parameter in assessing the size of the polar core of the reverse micelles, thereby impacting the total charge that is generated in the bulk solution as determined by conductivity. In the current study, this theory is extended to investigate the impact on particle charging. To accomplish this, the electrophoretic mobility is determined for a series of mineral oxides dispersed in Isopar-L with either Span 20, Span 80, or Span 85. These three surfactants all have the same head group chemistry, but their HLB value ranges from 1.8 to 8.6. It is found that the maximum observed particle electrophoretic mobility does scale directly with the HLB of the accompanying surfactant. This indicates that there is a direct correlation between a surfactant's ability to stabilize charge and its ability to impart charge to a particle. However, the largest HLB surfactant, Span 20, also exhibited a large amount of charge screening or neutralization at larger surfactant concentrations. This highlights the competition between particle charging and micelle-micelle charging that remains one of the largest obstacles to maximizing particle charge in apolar systems. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Mechanisms of nanoparticle internalization and transport across an intestinal epithelial cell model: effect of size and surface charge. (United States)

    Bannunah, Azzah M; Vllasaliu, Driton; Lord, Jennie; Stolnik, Snjezana


    This study investigated the effect of nanoparticle size (50 and 100 nm) and surface charge on their interaction with Caco-2 monolayers as a model of the intestinal epithelium, including cell internalization pathways and the level of transepithelial transport. Initially, toxicity assays showed that cell viability and cell membrane integrity were dependent on the surface charge and applied mass, number, and total surface area of nanoparticles, as tested in two epithelial cell lines, colon carcinoma Caco-2 and airway Calu-3. This also identified suitable nanoparticle concentrations for subsequent cell uptake experiments. Nanoparticle application at doses below half maximal effective concentration (EC₅₀) revealed that the transport efficiency (ratio of transport to cell uptake) across Caco-2 cell monolayers is significantly higher for negatively charged nanoparticles compared to their positively charged counterparts (of similar size), despite the higher level of internalization of positively charged systems. Cell internalization pathways were hence probed using a panel of pharmacological inhibitors aiming to establish whether the discrepancy in transport efficiency is due to different uptake and transport pathways. Vesicular trans-monolayer transport for both positively and negatively charged nanoparticles was confirmed via inhibition of dynamin (by dynasore) and microtubule network (via nocodazole), which significantly reduced the transport of both nanoparticle systems. For positively charged nanoparticles a significant decrease in internalization and transport (46% and 37%, respectively) occurred in the presence of a clathrin pathway inhibitor (chlorpromazine), macropinocytosis inhibition (42%; achieved by 5-(N-ethyl-N-isopropyi)-amiloride), and under cholesterol depletion (38%; via methyl-β-cyclodextrin), but remained unaffected by the inhibition of lipid raft associated uptake (caveolae) by genistein. On the contrary, the most prominent reduction in

  15. Modeling of the cranking and charging processes of conventional valve regulated lead acid (VRLA) batteries in micro-hybrid applications (United States)

    Gou, Jun; Lee, Anson; Pyko, Jan


    The cranking and charging processes of a VRLA battery during stop-start cycling in micro-hybrid applications were simulated by one dimensional mathematical modeling, to study the formation and distribution of lead sulfate across the cell and analyze the resulting effect on battery aging. The battery focused on in this study represents a conventional VRLA battery without any carbon additives in the electrodes or carbon-based electrodes. The modeling results were validated against experimental data and used to analyze the "sulfation" of negative electrodes - the common failure mode of lead acid batteries under high-rate partial state of charge (HRPSoC) cycling. The analyses were based on two aging mechanisms proposed in previous studies and the predictions showed consistency with the previous teardown observations that the sulfate formed at the negative interface is more difficult to be converted back than anywhere else in the electrodes. The impact of cranking pulses during stop-start cycling on current density and the corresponding sulfate layer production was estimated. The effects of some critical design parameters on sulfate formation, distribution and aging over cycling were investigated, which provided guidelines for developing models and designing of VRLA batteries in micro-hybrid applications.

  16. Polyvinylidene fluoride/nickel composite materials for charge storing, electromagnetic interference absorption, and shielding applications (United States)

    Gargama, H.; Thakur, A. K.; Chaturvedi, S. K.


    In this paper, the composites of polyvinylidene fluoride (PVDF)/nickel (Ni) prepared through simple blending and hot-molding process have been investigated for dielectric, electromagnetic shielding, and radar absorbing properties. In order to study complex permittivity of the composites in 40 Hz-20 MHz frequency range, impedance spectroscopy (IS) technique is used. Besides, the complex permittivity and permeability in addition to shielding effectiveness (SE), reflection coefficient (backed by air), and loss factor are calculated using scattering parameters measured in X-band (8.2-12.4 GHz) by waveguide method. Further, in X-band, a theoretical analysis of single layer absorbing structure backed by perfect electrical conductor is then performed. A flanged coaxial holder has also been designed, fabricated, calibrated, and tested for electromagnetic interference SE measurement in the broad frequency range (50 MHz-18 GHz). The IS results indicate large enhancement in dielectric constant as a function of Ni loading in the polymer-metal composite (PMC) phase. This result has been explained using interfacial polarization and percolation theory. The frequency dependent response of ac conductivity has been analyzed by fitting the experimental data to the "Johnscher's universal dielectric response law" model. The results obtained for SE (in X-band over broad frequency range) and reflection coefficient indicate that PVDF/Ni composites give better electromagnetic interference shielding and radar absorption properties at filler concentration (fcon) ≥ fc in the PMC, whereas at fc < fcon, the charge storage mechanism dominates in the insulator regime of the composite phase. Therefore, the range of PMC compositions below and above percolation threshold has been observed to have different variety of applications.

  17. Predicting the effect of charged particles for instantaneous and protracted irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Herr, Lisa; Tommasino, Francesco; Seeger, Adrian; Scholz, Uwe; Friedrich, Thomas; Scholz, Michael [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Durante, Marco [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Institut fuer Festkoerperphysik, TU Darmstadt, Darmstadt (Germany)


    The local effect model (LEM) predicts the relative biological effectiveness for charged particle radiation based on the dose response of radiation with low linear energy transfer such as X-rays. The induction of DNA double strand breaks after irradiation is simulated according to the track structure of charged particles. The effect of these lesions is then derived from the effect after photon irradiation causing a similar damage pattern. The LEM has been tested thoroughly using in-vitro and in-vivo experiments as well as clinical findings of carbon ion therapy. General properties of dose response curves can be derived from the conceptual basis of the LEM. Furthermore, insight in damage repair kinetics and the response to time dependent dose delivery is gained. In this contribution, the concept of the LEM is reviewed and some examples for its applicability are briefly discussed. General properties of the dose response curves are motivated. Finally, cell survival curves after protracted irradiation as well as the measured time dependence of residual damage after instantaneous irradiation are compared with the model predictions. Here, good agreement is found.

  18. Conjugated ionomers for photovoltaic applications: electric field driven charge separation in organic photovoltaics. Final Technical report

    Energy Technology Data Exchange (ETDEWEB)

    Lonergan, Mark [Univ. of Oregon, Eugene, OR (United States)


    Final technical report for Conjugated ionomers for photovoltaic applications, electric field driven charge separation in organic photovoltaics. The central goal of the work we completed was been to understand the photochemical and photovoltaic properties of ionically functionalized conjugated polymers (conjugated ionomers or polyelectrolytes) and energy conversion systems based on them. We primarily studied two classes of conjugated polymer interfaces that we developed based either upon undoped conjugated polymers with an asymmetry in ionic composition (the ionic junction) or doped conjugated polymers with an asymmetry in doping type (the p-n junction). The materials used for these studies have primarily been the polyacetylene ionomers. We completed a detailed study of p-n junctions with systematically varying dopant density, photochemical creation of doped junctions, and experimental and theoretical work on charge transport and injection in polyacetylene ionomers. We have also completed related work on the use of conjugated ionomers as interlayers that improve the efficiency or organic photovoltaic systems and studied several important aspects of the chemistry of ionically functionalized semiconductors, including mechanisms of so-called "anion-doping", the formation of charge transfer complexes with oxygen, and the synthesis of new polyfluorene polyelectrolytes. We also worked worked with the Haley group at the University of Oregon on new indenofluorene-based organic acceptors.

  19. Electrodeposited reduced-graphene oxide/cobalt oxide electrodes for charge storage applications

    Energy Technology Data Exchange (ETDEWEB)

    García-Gómez, A. [CQE, Instituto Superior Técnico, Universidade de Lisboa, Lisboa (Portugal); Eugénio, S., E-mail: [CQE, Instituto Superior Técnico, Universidade de Lisboa, Lisboa (Portugal); Duarte, R.G. [CQE, Instituto Superior Técnico, Universidade de Lisboa, Lisboa (Portugal); ESTBarreiro, Instituto Politécnico de Setúbal, Setúbal (Portugal); Silva, T.M. [CQE, Instituto Superior Técnico, Universidade de Lisboa, Lisboa (Portugal); ADEM, GI-MOSM, ISEL-Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, Lisboa (Portugal); Carmezim, M.J. [CQE, Instituto Superior Técnico, Universidade de Lisboa, Lisboa (Portugal); ESTSetúbal, Instituto Politécnico de Setúbal, Setúbal (Portugal); Montemor, M.F. [CQE, Instituto Superior Técnico, Universidade de Lisboa, Lisboa (Portugal)


    Highlights: • Electrochemically reduced graphene/CoOx composites were successfully produced by electrodeposition. • The composite material presents a specific capacitance of about 430 F g{sup −1}. • After heat treatment, the capacitance retention of the composite was 76% after 3500 cycles. - Abstract: In the present work, electrochemically reduced-graphene oxide/cobalt oxide composites for charge storage electrodes were prepared by a one-step pulsed electrodeposition route on stainless steel current collectors and after that submitted to a thermal treatment at 200 °C. A detailed physico-chemical characterization was performed by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and Raman spectroscopy. The electrochemical response of the composite electrodes was studied by cyclic voltammetry and charge-discharge curves and related to the morphological and phase composition changes induced by the thermal treatment. The results revealed that the composites were promising materials for charge storage electrodes for application in redox supercapacitors, attaining specific capacitances around 430 F g{sup −1} at 1 A g{sup −1} and presenting long-term cycling stability.

  20. Measurements of Charge Sharing Effects in Pixilated CZT/CdTe Detectors

    DEFF Research Database (Denmark)

    Kuvvetli, Irfan; Budtz-Jørgensen, Carl


    In this paper, charge sharing and charge loss effects in pixilated CZT/CdTe detectors are investigated by measurements. We measured charge sharing effects function of the inter-pixel gap (with same pixel pitch), the photon energy and the detector bias voltage for a large numbers of CZT and CdTe...... pixel detector samples. The results are used for the development of the large area X-ray and Gamma ray detector for the Atmosphere-Space Interactions Monitor (ASIM) planned for the ISS ESA Columbus module. Charge sharing measurements on detector samples with identical size and pixel geometry...

  1. Estimation of Transformer Parameters and Loss Analysis for High Voltage Capacitor Charging Application

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Schneider, Henrik; Ouyang, Ziwei


    In a bi-directional DC-DC converter for capacitive charging application, the losses associated with the transformer makes it a critical component. In order to calculate the transformer losses, its parameters such as AC resistance, leakage inductance and self capacitance of the high voltage (HV......) winding has to be estimated accurately. This paper analyzes the following losses of bi-directional flyback converter namely switching loss, conduction loss, gate drive loss, transformer core loss, and snubber loss, etc. Iterative analysis of transformer parameters viz., AC resistance, leakage inductance...

  2. Analysis of effective pulse current charging method for lithium ion battery (United States)

    Majid, N.; Hafiz, S.; Arianto, S.; Yuono, R. Y.; Astuti, E. T.; Prihandoko, B.


    Pulse charging methods has been developed as one of the fast charging methods for Lithium ion battery. This technique applies the continuous constant current pulse with certain pulse width until the battery fully charged. In this research, four Lithium polymer batteries of same type and capacity were used and subjected by several current pulses as a variable. The phenomenon of capacity loss as an effect of charging method was analysed every ten charge-discharge cycles. Four batteries were charged using constant current (1C) for 30 minutes to fill half of the total capacity, which then continued by pulse current of different pulse width in order to reach full capacity of each battery. Constant current charging for one hour was also applied to each battery as a comparison with that of pulse current charging data. The similar degradation patterns on battery capacity were observed. Nevertheless, the percentage of capacity loss is different. In conclusion, this method can be considered as one of the effective charging method, owing to the smallest capacity loss and shorter charging time.

  3. EV Charging Facilities and Their Application in LV Feeders with Photovoltaics

    DEFF Research Database (Denmark)

    Marra, Francesco; Yang, Guangya; Træholt, Chresten


    for the different locations in the feeder. With time-series simulations, we quantify the energy size required for a station ESS. A Belgian LV residential grid, modeled using real PV generation and load profiles, is used as case study. The method and simulation results show the effectiveness of using public EV...... charging facilities with the additional function of voltage regulation in feeders with PV....

  4. Charge Splitting In Situ Recorder (CSIR) for Real-Time Examination of Plasma Charging Effect in FinFET BEOL Processes (United States)

    Tsai, Yi-Pei; Hsieh, Ting-Huan; Lin, Chrong Jung; King, Ya-Chin


    A novel device for monitoring plasma-induced damage in the back-end-of-line (BEOL) process with charge splitting capability is first-time proposed and demonstrated. This novel charge splitting in situ recorder (CSIR) can independently trace the amount and polarity of plasma charging effects during the manufacturing process of advanced fin field-effect transistor (FinFET) circuits. Not only does it reveal the real-time and in situ plasma charging levels on the antennas, but it also separates positive and negative charging effect and provides two independent readings. As CMOS technologies push for finer metal lines in the future, the new charge separation scheme provides a powerful tool for BEOL process optimization and further device reliability improvements.

  5. Charging process of polyurethane based composites under electronic irradiation: Effects of cellulose fiber content (United States)

    Hadjadj, Aomar; Jbara, Omar; Tara, Ahmed; Gilliot, Mickael; Dellis, Jean-Luc


    The study deals with the charging effect of polyurethanes-based composites reinforced with cellulose fibers, under electronic beam irradiation in a scanning electron microscope. The results indicate that the leakage current and the trapped charge as well as the kinetics of charging process significantly change beyond a critical concentration of 10% cellulose fibers. These features are correlated with the cellulose concentration-dependence of the electrical properties, specifically resistivity and capacitance, of the composite.

  6. Piezotronic Effect: An Emerging Mechanism for Sensing Applications

    Directory of Open Access Journals (Sweden)

    Kory Jenkins


    Full Text Available Strain-induced polarization charges in a piezoelectric semiconductor effectively modulate the band structure near the interface and charge carrier transport. Fundamental investigation of the piezotronic effect has attracted broad interest, and various sensing applications have been demonstrated. This brief review discusses the fundamentals of the piezotronic effect, followed by a review highlighting important applications for strain sensors, pressure sensors, chemical sensors, photodetectors, humidity sensors and temperature sensors. Finally, the review offers some perspectives and outlook for this new field of multi-functional sensing enabled by the piezotronic effect.

  7. Effective Electrostatic Interactions Between Two Overall Neutral Surfaces with Quenched Charge Heterogeneity Over Atomic Length Scale (United States)

    Zhou, S.


    Using Monte Carlo results as a reference, a classical density functional theory ( CDFT) is shown to reliably predict the forces between two heterogeneously charged surfaces immersed in an electrolyte solution, whereas the Poisson-Boltzmann ( PB) theory is demonstrated to deteriorate obviously for the same system even if the system parameters considered fall within the validity range of the PB theory in the homogeneously charged surfaces. By applying the tested CDFT, we study the effective electrostatic potential of mean force ( EPMF) between two face-face planar and hard surfaces of zero net charge on which positive and negative charges are separated and considered to present as discontinuous spots on the inside edges of the two surfaces. Main conclusions are summarized as follows: (i) strength of the EPMF in the surface charge separation case is very sensitively and positively correlated with the surface charge separation level and valency of the salt ion. Particularly, the charge separation level and the salt ion valency have a synergistic effect, which makes high limit of the EPMF strength in the surface charge separation case significantly go beyond that of the ideal homogeneously charged surface counterpart at average surface charge density similar to the average surface positive or negative charge density in the charge separation case. (ii) The surface charge distribution patterns mainly influence sign of the EPMF: symmetrical and asymmetrical patterns induce repulsive and attractive (at small distances) EPMF, respectively; but with low valency salt ions and low charge separation level the opposite may be the case. With simultaneous presence of both higher valency cation and anion, the EPMF can be repulsive at intermediate distances for asymmetrical patterns. (iii) Salt ion size has a significant impact, which makes the EPMF tend to become more and more repulsive with the ion diameter regardless of the surface charge distribution patterns and the valency of

  8. The Effect of Molar Mass and Charge Density on the Formation of Complexes between Oppositely Charged Polyelectrolytes

    Directory of Open Access Journals (Sweden)

    Feriel Meriem Lounis


    Full Text Available The interactions between model polyanions and polycations have been studied using frontal continuous capillary electrophoresis (FACCE which allows the determination of binding stoichiometry and binding constant of the formed polyelectrolyte complex (PEC. In this work, the effect of the poly(l-lysine (PLL molar mass on the interaction with statistical copolymers of acrylamide and 2-acrylamido-2-methyl-1-propanesulfonate (PAMAMPS has been systematically investigated for different PAMAMPS chemical charge densities (15% and 100% and different ionic strengths. The study of the ionic strength dependence of the binding constant allowed the determination of the total number of released counter-ions during the formation of the PEC, which can be compared to the total number of counter-ions initially condensed on the individual polyelectrolyte partners before the association. Interestingly, this fraction of released counter-ions, which was strongly dependent on the PLL molar mass, was almost independent of the PAMAMPS charge density. These findings are useful to predict the binding constant according to the molar mass and charge density of the polyelectrolyte partners.

  9. An Integrated Data Analysis model to determine ion effective charge from beam attenuation and charge exchange emission measurements (United States)

    Nornberg, M. D.; den Hartog, D. J.; Reusch, L. M.


    We have created a forward model for charge-exchange impurity density measurements that incorporates neutral beam attenuation measurements self-consistently for determining the ion effective charge Zeff in MST PPCD plasmas. Detailed knowledge of Zeff is critical to determining the resistive dissipation of hot plasmas and requires knowledge of the impurity content and dynamics. Previously, Zeff profiles were determined from soft-x-ray brightness measurements by using charge-exchange impurity density measurements as prior information using an Integrated Data Analysis (IDA) method. The model is extended to include a self-consistent calculation of the neutral beam attenuation and includes measurements of the beam Doppler-shift spectrum and shine-through particle flux. Methods of experimental design are employed to calculate the information gained from different diagnostic combinations. The analysis shows that while attenuation measurements alone do not provide a unique impurity density measurement in the case of a multi-species inhomogeneous plasmas, they do provide a valuable measurement of the Zeff profile and constrain the range of contributing impurity densities. Supported by US DOE.

  10. The effects of ion adsorption on the potential of zero charge and the differential capacitance of charged aqueous interfaces (United States)

    Uematsu, Yuki; Netz, Roland R.; Bonthuis, Douwe Jan


    Using a box profile approximation for the non-electrostatic surface adsorption potentials of anions and cations, we calculate the differential capacitance of aqueous electrolyte interfaces from a numerical solution of the Poisson–Boltzmann equation, including steric interactions between the ions and an inhomogeneous dielectric profile. Preferential adsorption of the positive (negative) ion shifts the minimum of the differential capacitance to positive (negative) surface potential values. The trends are similar for the potential of zero charge; however, the potential of zero charge does not correspond to the minimum of the differential capacitance in the case of asymmetric ion adsorption, contrary to the assumption commonly used to determine the potential of zero charge. Our model can be used to obtain more accurate estimates of ion adsorption properties from differential capacitance or electrocapillary measurements. Asymmetric ion adsorption also affects the relative heights of the characteristic maxima in the differential capacitance curves as a function of the surface potential, but even for strong adsorption potentials the effect is small, making it difficult to reliably determine the adsorption properties from the peak heights.

  11. Electric field confinement effect on charge transport in organic field-effect transistors

    NARCIS (Netherlands)

    Li, X.; Kadashchuk, A.; Fishchuk, I.I.; Smaal, W.T.T.; Gelinck, G.H.; Broer, D.J.; Genoe, J.; Heremans, P.; Bässler, H.


    While it is known that the charge-carrier mobility in organic semiconductors is only weakly dependent on the electric field at low fields, the experimental mobility in organic field-effect transistors using silylethynyl-substituted pentacene is found to be surprisingly field dependent at low

  12. Scientific Computation Application Partnerships in Materials and Chemical Sciences, Charge Transfer and Charge Transport in Photoactivated Systems, Developing Electron-Correlated Methods for Excited State Structure and Dynamics in the NWChem Software Suite

    Energy Technology Data Exchange (ETDEWEB)

    Cramer, Christopher J. [Univ. of Minnesota, Minneapolis, MN (United States)


    Charge transfer and charge transport in photoactivated systems are fundamental processes that underlie solar energy capture, solar energy conversion, and photoactivated catalysis, both organometallic and enzymatic. We developed methods, algorithms, and software tools needed for reliable treatment of the underlying physics for charge transfer and charge transport, an undertaking with broad applicability to the goals of the fundamental-interaction component of the Department of Energy Office of Basic Energy Sciences and the exascale initiative of the Office of Advanced Scientific Computing Research.

  13. History of the Shaped Charge Effect: The First 100 Years (United States)


    in fig. I, and the tube is charged with mercury fulminate and fired by an electrically heated e whire. It seemed probable that the solid pellet...developed by the detonation or the fulminate . I accordingly suspended one about 2 feet above a larg: earthenware jar holding about five gallons of water

  14. Simulation of the perpendicular recording process including image charge effects

    NARCIS (Netherlands)

    Beusekamp, M.F.; Fluitman, J.H.J.


    This paper presents a complete model for the perpendicular recording process in single-pole-head keeper-layer configurations. It includes the influence of the image-charge distributions in the head and the keeper layer. Based on calculations of magnetization distributions in standstill situations,

  15. Electrostatic Charge Effects on Pharmaceutical Aerosol Deposition in Human Nasal–Laryngeal Airways

    Directory of Open Access Journals (Sweden)

    Jinxiang Xi


    Full Text Available Electrostatic charging occurs in most aerosol generation processes and can significantly influence subsequent particle deposition rates and patterns in the respiratory tract through the image and space forces. The behavior of inhaled aerosols with charge is expected to be most affected in the upper airways, where particles come in close proximity to the narrow turbinate surface, and before charge dissipation occurs as a result of high humidity. The objective of this study was to quantitatively evaluate the deposition of charged aerosols in an MRI-based nasal–laryngeal airway model. Particle sizes of 5 nm–30 µm and charge levels ranging from neutralized to ten times the saturation limit were considered. A well-validated low Reynolds number (LRN k–ω turbulence model and a discrete Lagrangian tracking approach that accounted for electrostatic image force were employed to simulate the nasal airflow and aerosol dynamics. For ultrafine aerosols, electrostatic charge was observed to exert a discernible but insignificant effect. In contrast, remarkably enhanced depositions were observed for micrometer particles with charge, which could be one order of magnitude larger than no-charge depositions. The deposition hot spots shifted towards the anterior part of the upper airway as the charge level increased. Results of this study have important implications for evaluating nasal drug delivery devices and for assessing doses received from pollutants, which often carry a certain level of electric charges.

  16. Separating Charges at Organic Interfaces: Effects of Disorder, Hot States, and Electric Field. (United States)

    Nayak, Pabitra K; Narasimhan, K L; Cahen, David


    Charge separation at organic-organic (O-O) interfaces is crucial to how many organic-based optoelectronic devices function. However, the mechanism of formation of spatially separated charge carriers and the role of geminate recombination remain topics of discussion and research. We review critically the contributions of the various factors, including electric fields, long-range order, and excess energy (beyond the minimum needed for photoexcitation), to the probability that photogenerated charge carriers will be separated. Understanding the processes occurring at the O/O interface and their relative importance for effective charge separation is crucial to design efficient solar cells and photodetectors. We stress that electron and hole delocalization after photoinduced charge transfer at the interface is important for efficient free carrier generation. Fewer defects at the interface and long-range order in the materials also improve overall current efficiency in solar cells. In efficient organic cells, external electric fields play only a small role for charge separation.

  17. Effect of Layer Charge on CO2and H2O Intercalations in Swelling Clays. (United States)

    Rao, Qi; Leng, Yongsheng


    The effect of layer charge on the intercalation of supercritical carbon dioxide (scCO 2 )-H 2 O mixture in Na-montmorillonite clay interlayers under T = 323 K and P = 90 bar geologic sequestration conditions has been further investigated. This effect includes the charge amount and its location (within either octahedral or tetrahedral layers due to isomorphic substitutions). Two clay models with different layer charges are used in this study. Simulation results show that the increase of charge amount shifts the monolayer-to-bilayer (1W-to-2W) hydration transition toward the lower relative humidity (RH), increasing water sorption at the expense of reducing the overall sorption amount of CO 2 in the clay interlayer. However, the combination of the influence of charge amount and charge location leads to insignificant changes in equilibrium basal spacings of the high- and low-charge clays. Molecular dynamics simulations show that the CO 2 dimers, which are frequently seen in low-charge clay interlayers, vanish in high-charge clay interlayers even at low RH of 30%.

  18. Antimicrobial effects of positively charged surfaces on adhering Gram-positive and Gram-negative bacteria

    NARCIS (Netherlands)

    Gottenbos, B; Grijpma, DW; van der Mei, HC; Feijen, J; Busscher, HJ

    The infection of biomaterials is determined by an interplay of adhesion and surface growth of the infecting organisms. In this study, the antimicrobial effects on adhering bacteria of a positively charged poly(methacrylate) surface ( potential +12 mV) were compared with those of negatively charged

  19. Effect of frequency variation on electromagnetic pulse interaction with charges and plasma

    NARCIS (Netherlands)

    Khachatryan, A.G.; van Goor, F.A.; Verschuur, Jeroen W.J.; Boller, Klaus J.


    The effect of frequency variation (chirp) in an electromagnetic (EM) pulse on the pulse interaction with a charged particle and plasma is studied. Various types of chirp and pulse envelopes are considered. In vacuum, a charged particle receives a kick in the polarization direction after interaction

  20. Incoherent Effect of Space Charge and Electron Cloud

    CERN Document Server

    Franchetti, G; Fischer, W; Zimmermann, F


    Trapping by resonances or scattering off resonances induced by space charge (SC) or electron cloud (EC) in conjunction with synchrotron motion can explain observations of slow beam loss and emittance growth, which are often accompanied by changes in the longitudinal beam profile. In this paper we review the recent progress in understanding and modeling of the underlying mechanisms, highlight the differences and similarities between space charge and electron cloud, and discuss simulation results in the light of experimental observations, e.g., at GSI, CERN, and BNL. In particular, we address the role of the pinched electrons and describe in detail the complexity of the electron pinch formation. We present simulation results within a dipole or in a field-free region of the beam pipe, which reveal the morphology and main features of this phenomenon, explain the physical origin of the complex electron structures like stripe in either field configuration, and discuss the dependence on some key parameters.

  1. Dynamical image-charge effect in molecular tunnel junctions

    DEFF Research Database (Denmark)

    Jin, Chengjun; Thygesen, Kristian Sommer


    When an electron tunnels between two metal contacts it temporarily induces an image charge (IC) in the electrodes which acts back on the tunneling electron. It is usually assumed that the IC forms instantaneously such that a static model for the image potential applies. Here we investigate how...... the finite IC formation time affects charge transport through a molecule suspended between two electrodes. For a single-level model, an analytical treatment shows that the conductance is suppressed by a factor Z(2), where Z is the quasiparticle renormalization factor, compared to the static IC approximation...... that the dynamical corrections can reduce the conductance by more than a factor of two when compared to static GW or density functional theory where the molecular energy levels have been shifted to match the exact quasiparticle levels....

  2. Effects of dislocation walls on charge carrier transport properties in CdTe single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Buis, C., E-mail: [CEA, LETI, MINATEC-Campus, 17 rue des Martyrs, F-38054 Grenoble (France); Gros d' Aillon, E. [CEA, LETI, MINATEC-Campus, 17 rue des Martyrs, F-38054 Grenoble (France); Lohstroh, A. [Department of physics, University of Surrey, Guilford GU2 7XH (United Kingdom); Marrakchi, G. [University of Saint-Etienne, Jean Monnet, F-42000 Saint-Etienne (France); Jeynes, C. [University of Surrey Ion Beam Centre, Nodus Centre, Stag Hill, Guildford GU2 7XH (United Kingdom); Verger, L. [CEA, LETI, MINATEC-Campus, 17 rue des Martyrs, F-38054 Grenoble (France)


    Radiation detectors for medical imaging at room temperature have been developed thanks to the availability of large chlorine-compensated cadmium telluride (CdTe:Cl) crystals. Microstructural defects affect the performance of CdTe:Cl radiation detectors. Advanced characterization tools, such as Ion Beam Induced Current (IBIC) measurements and chemical etching on tellurium and cadmium faces were used to evaluate the influence of sub-grain-boundaries on charge carrier transport properties. We performed IBIC imaging to correlate inhomogeneities in charge collection for both types of charge carrier with distribution of dislocation walls in the sample. This information should help improve performance in medical imaging applications.

  3. The electro-mechanical effect from charge dynamics on polymeric insulation lifetime


    Alghamdi, H.; Chen, G.; A. S. Vaughan


    For polymeric material used as electrical insulation, the presence of space charges could be the consequence of material degradations that are thermally activated but increased by the application of an electric field. The dynamics of space charge, therefore, can be potentially used to characterize the material. In this direction, a new aging model in which parameters have clear physical meanings has been developed and applied to the material to extrapolate the lifetime. The kinetic equation h...

  4. Amplitude-Mode Spectroscopy of Charge Excitations in PTB7 π -Conjugated Donor-Acceptor Copolymer for Photovoltaic Applications (United States)

    Baniya, Sangita; Vardeny, Shai R.; Lafalce, Evan; Peygambarian, Nasser; Vardeny, Z. Valy


    We measure the spectra of resonant Raman scattering and doping-induced absorption of pristine films of the π -conjugated donor-acceptor (D -A ) copolymer, namely, thieno[3,4 b]thiophene-alt-benzodithiophene (PTB7), as well as photoinduced absorption spectrum in a blend of PTB7 with fullerene phenyl-C61-butyric acid methyl ester molecules used for organic photovoltaic (OPV) applications. We find that the D -A copolymer contains six strongly coupled vibrational modes having relatively strong Raman-scattering intensity, which are renormalized upon adding charge polarons onto the copolymer chains either by doping or photogeneration. Since the lower-energy charge-polaron absorption band overlaps with the renormalized vibrational modes, they appear as antiresonance lines superposed onto the induced polaron absorption band in the photoinduced absorption spectrum but less so in the doping-induced absorption spectrum. We show that the Raman-scattering, doping-, and photoinduced absorption spectra of PTB7 are well explained by the amplitude mode model, where a single vibrational propagator describes the renormalized modes and their related intensities in detail. From the relative strengths of the induced infrared activity of the polaron-related vibrations and electronic transitions, we obtain the polaron effective kinetic mass in PTB7 using the amplitude mode model to be approximately 3.8 m* , where m* is the electron effective mass. The enhanced polaronic mass in PTB7 may limit the charge mobility, which, in turn, reduces the OPV solar-cell efficiency based on the PTB7-fullerene blend.

  5. The effects of particle charge on the performance of a filtering facepiece. (United States)

    Chen, C C; Huang, S H


    This study quantitatively determined the effect of electrostatic charge on the performance of an electret filtering facepiece. Monodisperse challenge corn oil aerosols with uniform charges were generated using a modified vibrating orifice monodisperse aerosol generator. The aerosol size distributions and concentrations upstream and downstream of an electret filter were measured using an aerodynamic particle sizer, an Aerosizer, and a scanning mobility particle sizer. The aerosol charge was measured by using an aerosol electrometer. The tested electret filter had a packing density of about 0.08, fiber size of 3 microns, and thickness of 0.75 mm. As expected, the primary filtration mechanisms for the micrometer-sized particles are interception and impaction, especially at high face velocities, while electrostatic attraction and diffusion are the filtration mechanisms for submicrometer-sized aerosol particles. The fiber charge density was estimated to be 1.35 x 10(-5) coulomb per square meter. After treatment with isopropanol, most of fiber charges were removed, causing the 0.3-micron aerosol penetration to increase from 36 to 68%. The air resistance of the filter increased slightly after immersion in the isopropanol, probably due to the coating of impurities in isopropanol. The aerosol penetration decreased with increasing aerosol charge. The most penetrating aerosol size became larger as the aerosol charge increased, e.g., from 0.32 to 1.3 microns when the aerosol charge increased from 0 to 500 elementary charges.

  6. Effective potentials for charge-helium and charge-singly-ionized helium interactions in a dense plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ramazanov, T.S.; Amirov, S.M.; Moldabekov, Zh.A. [Institute for Experimental and Theoretical Physics, Al-Farabi Kazakh National University, Almaty (Kazakhstan)


    The effective electron (proton)-He and electron (proton)-He{sup +} screened pair interaction potentials arising as a result of partial screening of the helium nucleus field by bound electrons, taking into account both screening by free charged particles and quantum diffraction effect in dense plasmas were derived. The impact of quantum effects on screening was analyzed. It was shown that plasma polarization around the atom leads to the additional repulsion (attraction) between the electron (proton) and the helium atom. The method of constructing the full electron (proton)-He and electron (proton)-He{sup +} screened pair interaction potentials as the sum of the derived potentials with the polarization potential and exchange potential is discussed. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. On Beam Matching and the Space-Charge Effect in protoDUNE-SP

    CERN Document Server

    Mandalia, Jesal Paresh


    In this project simulations using LArSoft have been analysed in particular looking at how the space-charge effect will affect the matching of particle tracks from the beam line monitor to the TPC and the TPC's performance measuring $\\frac{dE}{dx}$ in protoDUNE-SP. The analysis here provides some preliminary calibrations for protoDUNE-SP to account for the impact the space charge effect will have. Many areas of pion cross section analysis will be affected by the space charge effect so it is vital for a calibration to be developed.

  8. Charge and dielectric effects of biomolecules on electrical characteristics of nanowire FET biosensors (United States)

    Ahn, Jae-Hyuk; Choi, Sung-Jin; Im, Maesoon; Kim, Sungho; Kim, Chang-Hoon; Kim, Jee-Yeon; Park, Tae Jung; Lee, Sang Yup; Choi, Yang-Kyu


    The sensing mechanism of nanowire field effect transistor (NWFET) biosensors is investigated by taking into consideration both the charge and dielectric effects of biomolecules. The dielectric effect of the biomolecules is dominantly reflected in the linear regime, whereas the charge property is manifested in the subthreshold regime. The findings are supported by bio-experiments and numerical simulations. This study provides a rudimentary means of understanding interactions between biomolecules and NWFET biosensors.

  9. Fabrication and characterization of a charge-biased CMOS-MEMS resonant gate field effect transistor (United States)

    Chin, C. H.; Li, C. S.; Li, M. H.; Wang, Y. L.; Li, S. S.


    A high-frequency charge-biased CMOS-MEMS resonant gate field effect transistor (RGFET) composed of a metal-oxide composite resonant-gate structure and an FET transducer has been demonstrated utilizing the TSMC 0.35 μm CMOS technology with Q > 1700 and a signal-to-feedthrough ratio greater than 35 dB under a direct two-port measurement configuration. As compared to the conventional capacitive-type MEMS resonators, the proposed CMOS-MEMS RGFET features an inherent transconductance gain (gm) offered by the FET transduction capable of enhancing the motional signal of the resonator and relaxing the impedance mismatch issue to its succeeding electronics or 50 Ω-based test facilities. In this work, we design a clamped-clamped beam resonant-gate structure right above a floating gate FET transducer as a high-Q building block through a maskless post-CMOS process to combine merits from the large capacitive transduction areas of the large-width beam resonator and the high gain of the underneath FET. An analytical model is also provided to simulate the behavior of the charge-biased RGFET; the theoretical prediction is in good agreement with the experimental results. Thanks to the deep-submicrometer gap spacing enabled by the post-CMOS polysilicon release process, the proposed resonator under a purely capacitive transduction already attains motional impedance less than 10 kΩ, a record-low value among CMOS-MEMS capacitive resonators. To go one step further, the motional signal of the proposed RGFET is greatly enhanced through the FET transduction. Such a strong transmission and a sharp phase transition across 0° pave a way for future RGFET-type oscillators in RF and sensor applications. A time-elapsed characterization of the charge leakage rate for the floating gate is also carried out.

  10. Photovoltaic battery & charge controller market & applications survey. An evaluation of the photovoltaic system market for 1995

    Energy Technology Data Exchange (ETDEWEB)

    Hammond, R.L.; Turpin, J.F.; Corey, G.P. [and others


    Under the sponsorship of the Department of Energy, Office of Utility Technologies, the Battery Analysis and Evaluation Department and the Photovoltaic System Assistance Center of Sandia National Laboratories (SNL) initiated a U.S. industry-wide PV Energy Storage System Survey. Arizona State University (ASU) was contracted by SNL in June 1995 to conduct the survey. The survey included three separate segments tailored to: (a) PV system integrators, (b) battery manufacturers, and (c) PV charge controller manufacturers. The overall purpose of the survey was to: (a) quantify the market for batteries shipped with (or for) PV systems in 1995, (b) quantify the PV market segments by battery type and application for PV batteries, (c) characterize and quantify the charge controllers used in PV systems, (d) characterize the operating environment for energy storage components in PV systems, and (e) estimate the PV battery market for the year 2000. All three segments of the survey were mailed in January 1996. This report discusses the purpose, methodology, results, and conclusions of the survey.

  11. Microwave synthesis of noncentrosymmetric BaTiO3 truncated nanocubes for charge storage applications. (United States)

    Swaminathan, V; Pramana, Stevin S; White, T J; Chen, L; Chukka, Rami; Ramanujan, R V


    Truncated nanocubes of barium titanate (BT) were synthesized using a rapid, facile microwave-assisted hydrothermal route. Stoichiometric composition of pellets of nanocube BT powders was prepared by two-stage microwave process. Characterization by powder XRD, Rietveld refinement, SEM, TEM, and dielectric and polarization measurements was performed. X-ray diffraction revealed a polymorphic transformation from cubic Pm3̅m to tetragonal P4mm after 15 min of microwave irradiation, arising from titanium displacement along the c-axis. Secondary electron images were examined for nanocube BT synthesis and annealed at different timings. Transmission electron microscopy showed a narrow particle size distribution with an average size of 70 ± 9 nm. The remanence and saturation polarization were 15.5 ± 1.6 and 19.3 ± 1.2 μC/cm(2), respectively. A charge storage density of 925 ± 47 nF/cm(2) was obtained; Pt/BT/Pt multilayer ceramic capacitor stack had an average leakage current density of 5.78 ± 0.46 × 10(-8) A/cm(2) at ±2 V. The significance of this study shows an inexpensive and facile processing platform for synthesis of high-k dielectric for charge storage applications.

  12. Detailed numerical studies of space charge effects in an FEL RF gun

    CERN Document Server

    Cee, R R; Setzer, S; Weiland, T; Novokhatski, A


    The production of short bunches with low emittance is a key issue for the successful operation of an SASE-FEL as proposed by the TESLA collaboration (TESLA Technical design report, DESY 2001-011, Hamburg, 2001). In this paper we present the results of detailed MAFIA TS-2 (CST GmbH, Buedinger Strasse 2a, D-64289 Darmstadt) simulations for the FEL RF-gun revealing the main physical effects leading to emittance growth. The simulations prove that the transverse emittance growth can mainly be observed close to the cathode area. This is caused by the non-linear space charge forces acting inside the bunch during the injection process. For the application of an emittance compensation scheme (Nucl. Instr. and Meth. 285 (1989) 313) the slice emittance is of significant importance. Therefore, a wide range of parameters for the photo cathode laser has been investigated in order to find an appropriate operation point.

  13. SGFET as Charge Sensor: Application to Chemical and Biological Species Detection

    Directory of Open Access Journals (Sweden)

    T. Mohammed-Brahim


    Full Text Available A review of the large possibilities of sub-micron gap Suspended-Gate FETs, namely SGFET, to detect chemical and biologic species with high sensitivity, is presented. Examples of detection of humidity, gas, pH of liquid solutions, DNA (through one mutation of BRCA1 gene that is the main indication of the possibility for a woman to have breast cancer and proteins (through the transferrin that is the only carrier of iron in blood are presented to highlight these possibilities. The high sensitivity is explained from the charge distribution inside the sub-micron gap due to the high field effect.

  14. Calibration function for the Orbitrap FTMS accounting for the space charge effect. (United States)

    Gorshkov, Mikhail V; Good, David M; Lyutvinskiy, Yaroslav; Yang, Hongqian; Zubarev, Roman A


    Ion storage in an electrostatic trap has been implemented with the introduction of the Orbitrap Fourier transform mass spectrometer (FTMS), which demonstrates performance similar to high-field ion cyclotron resonance MS. High mass spectral characteristics resulted in rapid acceptance of the Orbitrap FTMS for Life Sciences applications. The basics of Orbitrap operation are well documented; however, like in any ion trap MS technology, its performance is limited by interactions between the ion clouds. These interactions result in ion cloud couplings, systematic errors in measured masses, interference between ion clouds of different size yet with close m/z ratios, etc. In this work, we have characterized the space-charge effect on the measured frequency for the Orbitrap FTMS, looking for the possibility to achieve sub-ppm levels of mass measurement accuracy (MMA) for peptides in a wide range of total ion population. As a result of this characterization, we proposed an m/z calibration law for the Orbitrap FTMS that accounts for the total ion population present in the trap during a data acquisition event. Using this law, we were able to achieve a zero-space charge MMA limit of 80 ppb for the commercial Orbitrap FTMS system and sub-ppm level of MMA over a wide range of total ion populations with the automatic gain control values varying from 10 to 10(7). Copyright © 2010 American Society for Mass Spectrometry. Published by Elsevier Inc. All rights reserved.

  15. A microscopic approach based on particle-vibration coupling: application to charge-exchange transitions and multiplets in odd nuclei

    Directory of Open Access Journals (Sweden)

    Colò Gianluca


    Full Text Available In this contribution, we shall describe a formalism that goes beyond the simple time-dependent mean field and is based on particle-vibration coupling (PVC. Such a formalism has been developed with the idea of being self-consistent. It makes use of Skyrme effective forces, and has been used for several applications. We will focus on charge-exchange transitions, namely we will show that our model describes well both the Gamow-Teller giant resonance width, and the low-lying transitions associated with β-decay. In this latter case, including PVC produces a significant improvement of the half-lives obtained at mean-field level, and leads to a good agreement with experimental data. We will end by discussing particle-phonon multiplets in odd nuclei.

  16. Design of a phytosphingosine-containing, positively-charged nanoemulsion as a colloidal carrier system for dermal application of ceramides. (United States)

    Yilmaz, Erol; Borchert, Hans-Hubert


    Positively charged oil/water (o/w) nanoemulsions (PN) are effective vehicles to change the permeability of the skin. This study focused on the preparation and characterisation of phytosphingosine (PS) containing PN (PPN) which serve as colloidal carriers for the dermal application of ceramide IIIB (CIIIB) and the stratum corneum (SC) lipids (PPNSC) such as ceramide III (CIII), cholesterol, and palmitic acid. The investigations were conducted using appropriate emulsification and homogenisation processing conditions to optimise PPNSC with regard to droplet size, physical stability, and solubility of PS, CIII and CIIIB. A decrease in droplet size was observed through eight homogenisation cycles at a pressure of 500 bar and a temperature of 50 degrees C. Above these optimal values, an increase in droplet size was observed. PS and ceramides have low solubilities in oil and water. When Lipoid E-80 (LE80) was added to the oil phase, the solubility of PS and ceramides increased, indicating some interactions shown by DSC measurements. SC lipids and CIIIB could be successfully incorporated in PPN without producing any physical instability. The high stability of PPNSC is probably due to the presence of a hydrophilic (Tween 80) and a lipophilic surfactant (LE80), supported by the lipophilic cosurfactant PS, at the o/w interface. It was shown that PS was responsible for the positive charge and thus supported the high physical stability of PPNSC. This optimised emulsion was selected for further skin absorption evaluation.

  17. Recent Advances in Two-Dimensional Materials with Charge Density Waves: Synthesis, Characterization and Applications

    Directory of Open Access Journals (Sweden)

    Mongur Hossain


    Full Text Available Recently, two-dimensional (2D charge density wave (CDW materials have attracted extensive interest due to potential applications as high performance functional nanomaterials. As other 2D materials, 2D CDW materials are layered materials with strong in-plane bonding and weak out-of-plane interactions enabling exfoliation into layers of single unit cell thickness. Although bulk CDW materials have been studied for decades, recent developments in nanoscale characterization and device fabrication have opened up new opportunities allowing applications such as oscillators, electrodes in supercapacitors, energy storage and conversion, sensors and spinelectronic devices. In this review, we first outline the synthesis techniques of 2D CDW materials including mechanical exfoliation, liquid exfoliation, chemical vapor transport (CVT, chemical vapor deposition (CVD, molecular beam epitaxy (MBE and electrochemical exfoliation. Then, the characterization procedure of the 2D CDW materials such as temperature-dependent Raman spectroscopy, temperature-dependent resistivity, magnetic susceptibility and scanning tunneling microscopy (STM are reviewed. Finally, applications of 2D CDW materials are reviewed.

  18. Point Mutations Effects on Charge Transport Properties of the Tumor-Suppressor Gene p53 (United States)

    Roemer, Rudolf A.; Shih, Chi-Tin; Roche, Stephan


    We report on a theoretical study of point mutations effects on charge transfer properties in the DNA sequence of the tumor-suppressor p53 gene. On the basis of effective tight-binding models which simulate hole propagation along the DNA, a statistical analysis of mutation-induced charge transfer modifications is performed. In contrast to non-cancerous mutations, mutation hotspots tend to result in significantly weaker changes of transmission properties. This suggests that charge transport could play a significant role for DNA-repairing deficiency yielding carcinogenesis.

  19. Space-charge effects in ultrahigh current electron bunches generated by laser-plasma accelerators

    National Research Council Canada - National Science Library

    Grüner, F. J; Schroeder, C. B; Maier, A. R; Becker, S; Mikhailova, J. M


    ...) generated in laser-plasma accelerators. At low electron energies such peak currents are expected to cause space-charge effects such as bunch expansion and induced energy variations along the bunch, potentially hindering the FEL process...

  20. Memory effect of low-temperature processed ZnO thin-film transistors having metallic nanoparticles as charge trapping elements. (United States)

    Park, Young-Su; Kim, Soo-Jin; Lyu, Si-Hoon; Lee, Byoung Hoon; Sung, Myung Mo; Lee, Jaegab; Lee, Jang-Sik


    In this study, non-volatile memory effect was characterized using the single-transistor-based memory devices based on self-assembled gold nanoparticles (AuNP) as the charge trapping elements and atomic-layer deposited ZnO as the channel layer. The fabricated memory devices showed controllable and reliable threshold voltage shifts according to the program/erase operations that resulted from the charging/discharging of charge carriers in the charge trapping elements. Reliable non-volatile memory properties were also confirmed by the endurance and data retention measurements. The low temperature processes of the key device elements, i.e., AuNP charge trapping layer and ZnO channel layer, enable the use of this device structure to the transparent/flexible non-volatile memory applications in the near future.

  1. Memory and nonlinear transport effects in charging-discharging of a supercapacitor (United States)

    Uchaikin, V. V.; Ambrozevich, A. S.; Sibatov, R. T.; Ambrozevich, S. A.; Morozova, E. V.


    We report on the results of analysis of the kinetics of charge-discharge current of Panasonic supercapacitors in a wide range of time from 10-1 to 104 s. The non-Debye behavior of relaxation observed earlier by us and other authors is confirmed experimentally, and the influence of the supercapacitor charging regime on this process for various previous histories (values of applied voltage, charging time, and load resistance) is analyzed. The results are compared with available experimental data for paper-oil and electrolytic capacitors and with the results of calculations in the linear response model. It is found that in contrast to conventional capacitors, the response of the supercapacitor under investigation to variations of the charging regime does not match the linear response model. The relation of this nonlinearity to processes in the double electric layer, the morphology of the porous electrode, and the effect of charge reversal in pores is considered.

  2. Effect of spatio-energy correlation in PCD due to charge sharing, scatter, and secondary photons (United States)

    Rajbhandary, Paurakh L.; Hsieh, Scott S.; Pelc, Norbert J.


    Charge sharing, scatter and fluorescence events in a photon counting detector (PCD) can result in multiple counting of a single incident photon in neighboring pixels. This causes energy distortion and correlation of data across energy bins in neighboring pixels (spatio-energy correlation). If a "macro-pixel" is formed by combining multiple small pixels, it will exhibit correlations across its energy bins. Charge sharing and fluorescence escape are dependent on pixel size and detector material. Accurately modeling these effects can be crucial for detector design and for model based imaging applications. This study derives a correlation model for the multi-counting events and investigates the effect in virtual non-contrast and effective monoenergetic imaging. Three versions of 1 mm2 square CdTe macro-pixel were compared: a 4×4 grid, 2×2 grid, or 1×1 composed of pixels with side length 250 μm, 500 μm, or 1 mm, respectively. The same flux was applied to each pixel, and pulse pile-up was ignored. The mean and covariance matrix of measured photon counts is derived analytically using pre-computed spatio-energy response functions (SERF) estimated from Monte Carlo simulations. Based on the Cramer-Rao Lower Bound, a macro-pixel with 250×250 μm2 sub-pixels shows 2.2 times worse variance than a single 1 mm2 pixel for spectral imaging, while its penalty for effective monoenergetic imaging is <10% compared to a single 1 mm2 pixel.

  3. Effects of gallopamil on calcium release and intramembrane charge movements in frog skeletal muscle fibres. (United States)

    Feldmeyer, D; Melzer, W; Pohl, B


    1. Intramembrane charge movements and changes in intracellular Ca2+ concentration were studied in voltage clamp experiments on cut twitch muscle fibres of the frog. The restoration from inactivation caused by steady depolarization and its modification by the phenylalkylamine Ca2+ channel antagonist gallopamil (D600, 10-30 microM) were investigated. 2. D600 prevented the restoration from inactivation of Ca2+ release which normally occurred at -80 mV. In D600 Ca2+ release recovered from inactivation at -120 mV. 3. D600 did not alter the characteristics of intramembrane charge movements in the depolarized fibre (charge 2) but the increase in the amount of mobile charge in the test voltage range above -60 mV, which normally occurs after changing the holding potential to -80 mV, was suppressed. The charge movement characteristics of D600-paralysed fibres, which were held at -80 mV, equalled those of normal depolarized and inactivated fibres. 4. Control records for the charge movement analysis were always obtained by voltage steps above 0 mV. Using the 'conventional' control in the potential range between -80 and -160 mV led to an underestimation and a kinetic deformation of charge movements in D600-treated fibres, which was due to various amounts of nonlinear charge in the control. 5. Like the restoration of Ca2+ release at -80 mV in normal fibres the recovery from paralysis at -120 mV in D600-treated fibres was accompanied by a significant increase in mobile charge in the potential range positive of -60 mV. Both Ca2+ release and charge movement at test potentials above -60 mV recovered with almost identical time course. 6. Restoration of Ca2+ release at a holding potential of -80 mV in normal fibres or at -120 mV in D600-treated fibres could not be clearly correlated to charge movement changes in the voltage range negative of -60 mV (charge 2). 7. Our results are consistent with a voltage-dependent inhibitory effect of D600 on the charge displacement that controls Ca2

  4. Fouling control mechanisms of demineralized water backwash: Reduction of charge screening and calcium bridging effects

    KAUST Repository

    Li, Sheng


    This paper investigates the impact of the ionic environment on the charge of colloidal natural organic matter (NOM) and ultrafiltration (UF) membranes (charge screening effect) and the calcium adsorption/bridging on new and fouled membranes (calcium bridging effect) by measuring the zeta potentials of membranes and colloidal NOM. Fouling experiments were conducted with natural water to determine whether the reduction of the charge screening effect and/or calcium bridging effect by backwashing with demineralized water can explain the observed reduction in fouling. Results show that the charge of both membranes and NOM, as measured by the zeta potential, became more negative at a lower pH and a lower concentration of electrolytes, in particular, divalent electrolytes. In addition, calcium also adsorbed onto the membranes, and consequently bridged colloidal NOM and membranes via binding with functional groups. The charge screening effect could be eliminated by flushing NOM and membranes with demineralized water, since a cation-free environment was established. However, only a limited amount of the calcium bridging connection was removed with demineralized water backwashes, so the calcium bridging effect mostly could not be eliminated. As demineralized water backwash was found to be effective in fouling control, it can be concluded that the reduction of the charge screening is the dominant mechanism for this. © 2011 Elsevier Ltd.

  5. Effect of relative humidity on the electrostatic charge properties of dry powder inhaler aerosols. (United States)

    Kwok, Philip Chi Lip; Chan, Hak-Kim


    At present, there is no published data examining the effect of relative humidity on the electrostatic charges of dry powder inhaler aerosols. The charging behaviour of two commercial products, Pulmicort and Bricanyl Turbuhalers, were investigated using an electrical low pressure impactor (ELPI). ELPI was successfully modified to disperse the aerosols at 60 l/min. Four doses from each new inhaler were sampled at 15, 40, 65, and 90% RH. Particles deposited on the impactor stages according to their aerodynamic diameters and their charges were measured simultaneously by the electrometers. The drug in each size fraction was quantified using HPLC. Both products generated bipolar charges. The charging behaviour of the two types of inhaler showed different humidity dependence although the mass output was not significantly affected. The absolute specific charge of budesonide fine particles from Pulmicort was the lowest at 40% RH but increased at lower and higher RHs. In contrast, the terbutaline sulfate fine particles from Bricanyl followed the expected trend of charge reduction with increasing RH. The distinct trends of charging of aerosols from Pulmicort and Bricanyl Turbuhalers was explained by differences in hygroscopicity and other physicochemical factors between the two drugs.

  6. Charge integration successive approximation analog-to-digital converter for focal plane applications using a single amplifier (United States)

    Zhou, Zhimin (Inventor); Pain, Bedabrata (Inventor)


    An analog-to-digital converter for on-chip focal-plane image sensor applications. The analog-to-digital converter utilizes a single charge integrating amplifier in a charge balancing architecture to implement successive approximation analog-to-digital conversion. This design requires minimal chip area and has high speed and low power dissipation for operation in the 2-10 bit range. The invention is particularly well suited to CMOS on-chip applications requiring many analog-to-digital converters, such as column-parallel focal-plane architectures.

  7. New density estimation methods for charged particle beams with applications to microbunching instability

    Directory of Open Access Journals (Sweden)

    Balša Terzić


    Full Text Available In this paper we discuss representations of charge particle densities in particle-in-cell simulations, analyze the sources and profiles of the intrinsic numerical noise, and present efficient methods for their removal. We devise two alternative estimation methods for charged particle distribution which represent significant improvement over the Monte Carlo cosine expansion used in the 2D code of Bassi et al. [G. Bassi, J. A. Ellison, K. Heinemann, and R. Warnock, Phys. Rev. ST Accel. Beams 12, 080704 (2009; PRABFM1098-440210.1103/PhysRevSTAB.12.080704G. Bassi and B. Terzić, in Proceedings of the 23rd Particle Accelerator Conference, Vancouver, Canada, 2009 (IEEE, Piscataway, NJ, 2009, TH5PFP043], designed to simulate coherent synchrotron radiation (CSR in charged particle beams. The improvement is achieved by employing an alternative beam density estimation to the Monte Carlo cosine expansion. The representation is first binned onto a finite grid, after which two grid-based methods are employed to approximate particle distributions: (i truncated fast cosine transform; and (ii thresholded wavelet transform (TWT. We demonstrate that these alternative methods represent a staggering upgrade over the original Monte Carlo cosine expansion in terms of efficiency, while the TWT approximation also provides an appreciable improvement in accuracy. The improvement in accuracy comes from a judicious removal of the numerical noise enabled by the wavelet formulation. The TWT method is then integrated into the CSR code [G. Bassi, J. A. Ellison, K. Heinemann, and R. Warnock, Phys. Rev. ST Accel. Beams 12, 080704 (2009PRABFM1098-440210.1103/PhysRevSTAB.12.080704], and benchmarked against the original version. We show that the new density estimation method provides a superior performance in terms of efficiency and spatial resolution, thus enabling high-fidelity simulations of CSR effects, including microbunching instability.

  8. Self-interaction effects on charge-transfer collisions

    CERN Document Server

    Quashie, Edwin E; Andrade, Xavier; Correa, Alfredo A


    In this article, we investigate the role of the self-interaction error in the simulation of collisions using time-dependent density functional theory (TDDFT) and Ehrenfest dynamics. We compare many different approximations of the exchange and correlation potential, using as a test system the collision of $\\mathrm{H^+ + CH_4}$ at $30~\\mathrm{eV}$. We find that semi-local approximations, like PBE, and even hybrid functionals, like B3LYP, produce qualitatively incorrect predictions for the scattering of the proton. This discrepancy appears because the self-interaction error allows the electrons to jump too easily to the proton, leading to radically different forces with respect to the non-self-interacting case. From our results, we conclude that using a functional that is self-interaction free is essential to properly describe charge-transfer collisions between ions and molecules in TDDFT.

  9. Effect of Coulomb correlation on charge transport in disordered organic semiconductors (United States)

    Liu, Feilong; van Eersel, Harm; Xu, Bojian; Wilbers, Janine G. E.; de Jong, Michel P.; van der Wiel, Wilfred G.; Bobbert, Peter A.; Coehoorn, Reinder


    Charge transport in disordered organic semiconductors, which is governed by incoherent hopping between localized molecular states, is frequently studied using a mean-field approach. However, such an approach only considers the time-averaged occupation of sites and neglects the correlation effect resulting from the Coulomb interaction between charge carriers. Here, we study the charge transport in unipolar organic devices using kinetic Monte Carlo simulations and show that the effect of Coulomb correlation is already important when the charge-carrier concentration is above 10-3 per molecular site and the electric field is smaller than 108 V/m. The mean-field approach is then no longer valid, and neglecting the effect can result in significant errors in device modeling. This finding is supported by experimental current density-voltage characteristics of ultrathin sandwich-type unipolar poly(3-hexylthiophene) (P3HT) devices, where high carrier concentrations are reached.

  10. Effects of dielectric charging on the output voltage of a capacitive accelerometer (United States)

    Qu, Hao; Yu, Huijun; Zhou, Wu; Peng, Bei; Peng, Peng; He, Xiaoping


    Output voltage drifting observed in one typical capacitive microelectromechanical system (MEMS) accelerometer is discussed in this paper. Dielectric charging effect is located as one of the major determinants of this phenomenon through a combination of experimental and theoretical studies. A theoretical model for the electromechanical effects of the dielectric surface charges within the electrode gap is established to analyze the dielectric charge effect on the output voltage. Observations of output voltage drift against time are fitted to this model in order to estimate the possible dielectric layer thickness. Meanwhile, Auger electron spectroscopy is carried out to analyze the electrode surface material composition and confirms a mixture layer of dielectric SiO2 and Si with a thickness about 5 nm, which is very close to the model estimation. In addition, observation of time-varing output drift in the variable bias voltage experiment indicates the movement of dielectric charge can be controlled by the applied electric field.

  11. Effects of variability and rate on battery charge storage and lifespan (United States)

    Krieger, Elena Marie

    The growing prevalence of hybrid and electric vehicles, intermittent renewable energy sources, and other complex power systems has triggered a rapid increase in demand for energy storage. Unlike portable electronic devices, whose batteries can be recharged according to a pre-determined protocol simply by plugging them into the wall, many of these applications are characterized by highly variable charge and demand profiles. The central objective of this work is to assess the impact of power distribution and frequency on battery behavior in order to improve overall system efficiency and lifespan in these variable power applications. We first develop and experimentally verify a model to describe the trade-off between battery charging power and energy stored to assess how varying power input affects battery efficiency. This relationship is influenced both by efficiency losses at high powers and by premature voltage cutoffs, which contribute to incomplete battery charging and discharging. We experimentally study the impact of variable power on battery aging in lead-acid, nickel metal hydride, lithium-ion and lithium iron phosphate batteries. As a case study we focus on off-grid wind systems, and analyze the impact of both power distribution and frequency on charge acceptance and degradation in each of these chemistries. We suggest that lithium iron phosphate batteries may be more suitable for off-grid electrification projects than standard lead-acid batteries. We experimentally assess the impact of additional variable charging parameters on battery performance, including the interplay between efficiency, frequency of power oscillations, state-of-charge, incomplete charging and path dependence. We develop a frequency-domain model for hybrid energy storage systems that couples non-stationary frequency analysis of variable power signals to a frequency-based metric for energy storage device performance. The experimental and modeling work developed herein can be utilized to

  12. Investigation of space charge distribution of low-density polyethylene/GO-GNF (graphene oxide from graphite nanofiber) nanocomposite for HVDC application. (United States)

    Kim, Yoon Jin; Ha, Son-Tung; Lee, Gun Joo; Nam, Jin Ho; Ryu, Ik Hyun; Nam, Su Hyun; Park, Cheol Min; In, Insik; Kim, Jiwan; Han, Chul Jong


    This paper reported a research on space charge distribution in low-density polyethylene (LDPE) nanocomposites with different types of graphene and graphene oxide (GO) at low filler content (0.05 wt%) under high DC electric field. Effect of addition of graphene oxide or graphene, its dispersion in LDPE polymer matrix on the ability to suppress space charge generation will be investigated and compared with MgO/LDPE nanocomposite at the same filler concentration. At an applied electric field of 80 kV/mm, a positive packet-like charge was observed in both neat LDPE, MgO/LDPE, and graphene/LDPE nanocomposites, whereas only little homogenous space charge was observed in GO/LDPE nanocomposites, especially with GO synthesized from graphite nano fiber (GNF) which is only -100 nm in diameter. Our research also suggests that dispersion of graphene oxide particles on the polymer matrix plays a significant role to the performance of nanocomposites on suppressing packet-like space charge. From these results, it is expected that nano-sized GO synthesized from GNF can be a promising filler material to LDPE composite for HVDC applications.

  13. Influence of the charge of chromite-magnesite dust on the effectiveness of its removal in a bag filter

    Energy Technology Data Exchange (ETDEWEB)

    Saranchuk, V.I.; Maslov, A.E.; Rekun, V.V.


    This paper presents results of work on determination of the effectiveness of filtering of chromite-magnesite dust with similar and different charging of the particles and the surface of the filter cloth. On the basis of investigations of the contact interactions of mineral dusts with polymer materials a device was developed for charging of a dust aerosol which makes it possible to charge neutral and recharge positively charged particles to a negative polarity. The results presented show an increase in the effectiveness of removal of the dust from 97.33 to 98.49% as the result of the change in its charge with the use of the charging device.

  14. A Lossy Counting-Based State of Charge Estimation Method and Its Application to Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Hong Zhang


    Full Text Available Estimating the residual capacity or state-of-charge (SoC of commercial batteries on-line without destroying them or interrupting the power supply, is quite a challenging task for electric vehicle (EV designers. Many Coulomb counting-based methods have been used to calculate the remaining capacity in EV batteries or other portable devices. The main disadvantages of these methods are the cumulative error and the time-varying Coulombic efficiency, which are greatly influenced by the operating state (SoC, temperature and current. To deal with this problem, we propose a lossy counting-based Coulomb counting method for estimating the available capacity or SoC. The initial capacity of the tested battery is obtained from the open circuit voltage (OCV. The charging/discharging efficiencies, used for compensating the Coulombic losses, are calculated by the lossy counting-based method. The measurement drift, resulting from the current sensor, is amended with the distorted Coulombic efficiency matrix. Simulations and experimental results show that the proposed method is both effective and convenient.

  15. An electrostatic charge sensor based on micro resonator with sensing scheme of effective stiffness perturbation (United States)

    Chen, Dongyang; Zhao, Jiuxuan; Wang, Yinshen; Xie, Jin


    A resonant electrostatic charge sensor with high sensitivity based on micro electromechanical systems (MEMS) technology is proposed to measure electric charge. Input charge produces lateral electrostatic force to change effective stiffness of double-ended tuning forks resonator, and leads to a resonant frequency shift. The sensitivity of the charge sensor is 4.4  ×  10-4 Hz fC-2. The proposed sensing scheme of effective stiffness perturbation has higher sensitivity than the traditional axial strain sensing methods. Experimental results show that the frequency modulation has better resolution and stability than the amplitude modulation. The proposed sensing scheme also creates additional energy transmission paths inside the device to improve quality factor and stabilize frequency fluctuation. The instability of resonant frequency induced by mechanical nonlinearity are investigated.

  16. Maxwell–Wagner Effect in Multi-Layered Dielectrics: Interfacial Charge Measurement and Modelling

    Directory of Open Access Journals (Sweden)

    Thi Thu Nga Vu


    Full Text Available The development of high voltage direct current (HVDC technologies generates new paradigms in research. In particular and contrary to the AC case, investigation of electrical conduction is not only needed for understanding the dielectric breakdown but also to describe the field distribution inside the insulation. Here, we revisit the so-called Maxwell–Wagner effect in multi-layered dielectrics by considering on the one hand a non-linear field dependent model of conductivity and on the other hand by performing space charge measurements giving access to the interfacial charge accumulated between different dielectrics. We show that space charge measurements give access to the amount of interfacial charge built-up by the Maxwell–Wagner effect between two dielectrics of different natures. Measurements also demonstrate that the field distribution undergoes a transition from a capacitive distribution to a resistive one, under long lasting stress.

  17. Effect of dielectric interface on charge aggregation in the voltage-gated K+ ion channel (United States)

    Adhya, Lipika; Mapder, Tarunendu; Adhya, Samit


    Background: There is experimental evidence of many cases of stable macromolecular conformations with charged amino-acids facing lipid, an arrangement thought to be energetically unfavourable. Methods and Objectives: Employing classical electrostatics, we show that, this is not necessarily the case and studied the physical basis of the specific role of proximity of charges to the dielectric interface between two different environments. We illustrate how self and induced energies due to the dielectric medium polarization, on either side of the interface, contribute differentially to the stability of a pair of charges and hence the mutual conformation of the S3b-S4 α-helix pair of the voltage-gated K+ channel. Results and Conclusion: We show that (1) a pair of opposite charges on either side of lipid-protein interface confers significant stability; (2) hydrophobic media has an important role in holding together two similar repelling charges; (3) dielectric interface has stabilizing effect on a pair of charges, when an ion is closer to its interface than its neighboring charge; (4) in spite of the presence of dielectric interface, there is a nonexistence of any dielectric effect, when an ion is equidistant from its image and neighboring charge. We also demonstrate that, variation in dielectric media of the surrounding environment confers new mutual conformations to S3b-S4 α-helices of voltage sensor domain at zero potential, especially lipid environment on the helix side, which improved stability to the configuration by lowering the potential energy. Our results provide an answer to the long standing question of why charges face hydrophobic lipid membranes in the stable conformation of a protein. PMID:25810659

  18. Effects of discrete stochastic charging of dust grains in protoplanetary disks (United States)

    Ashrafi, K. S.; Esparza, S.; Xiang, C.; Matthews, L.; Carballido, A.; Hyde, T.; Shotorban, B.


    The stochastic nature of grain charging can play a significant role in the development of dust aggregate structure when the grains have a small charge. In this work, we use a model of discrete stochastic charging to calculate time-dependent electric charging of dust aggregates. We compare the electron and ion currents to micron and submicron aggregate grains, which consist of spherical monomers, to the currents to spherical grains of equivalent mass. The average charge and charge distribution are compared for aggregates composed of different monomer sizes. The aggregate morphology (whether the grain is compact or porous) affects the amount of charge collected and the available surface area for recombination on dust grains. Thus, the aggregate morphology as well as the dust fraction can affect the overall ionization balance in a plasma. The implications of our results for non-ideal magnetohydrodynamics in protoplanetary disks are briefly discussed in terms of the effect of disk ionization fraction and chemical networks. This work was supported by the National Science Foundation under Grant PHY-1414523.

  19. Neutralized ion beam modification of cellulose membranes for study of ion charge effect on ion-beam-induced DNA transfer

    Energy Technology Data Exchange (ETDEWEB)

    Prakrajang, K., E-mail: [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Sangwijit, K.; Anuntalabhochai, S. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Wanichapichart, P. [Membrane Science and Technology Research Center, Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai, Songkla 90110 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Yu, L.D., E-mail: [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)


    Low-energy ion beam biotechnology (IBBT) has recently been rapidly developed worldwide. Ion-beam-induced DNA transfer is one of the important applications of IBBT. However, mechanisms involved in this application are not yet well understood. In this study plasma-neutralized ion beam was applied to investigate ion charge effect on induction of DNA transfer. Argon ion beam at 7.5 keV was neutralized by RF-driven plasma in the beam path and then bombarded cellulose membranes which were used as the mimetic plant cell envelope. Electrical properties such as impedance and capacitance of the membranes were measured after the bombardment. An in vitro experiment on plasmid DNA transfer through the cellulose membrane was followed up. The results showed that the ion charge input played an important role in the impedance and capacitance changes which would affect DNA transfer. Generally speaking, neutral particle beam bombardment of biologic cells was more effective in inducing DNA transfer than charged ion beam bombardment.

  20. Effect of Molecular Packing and Charge Delocalization on the Nonradiative Recombination of Charge-Transfer States in Organic Solar Cells

    KAUST Repository

    Chen, Xian Kai


    In organic solar cells, a major source of energy loss is attributed to nonradiative recombination from the interfacial charge transfer states to the ground state. By taking pentacene–C60 complexes as model donor–acceptor systems, a comprehensive theoretical understanding of how molecular packing and charge delocalization impact these nonradiative recombination rates at donor–acceptor interfaces is provided.

  1. Effect of dielectronic recombination on the charge-state distribution ...

    Indian Academy of Sciences (India)

    tion of CVI to CV ions and ratio of line intensity emitted from them for two representative formulations of dielectronic recombination ... These lines lie in the water window spectral range (23 Å to 44 Å corresponding ... not applicable. From the above equation one can calculate the fractional densities δ(Z)(δ(Z) = n(Z)/ni, ni = ∑.

  2. 47 CFR 1.1108 - Schedule of charges for applications and other filings for the international telecommunication... (United States)


    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Schedule of charges for applications and other filings for the international telecommunication services. 1.1108 Section 1.1108 Telecommunication FEDERAL... telecommunication services. Remit payment (along with a copy of invoice) for these services to the: Federal...

  3. Manipulation of charge transfer and transport in plasmonic-ferroelectric hybrids for photoelectrochemical applications (United States)

    Wang, Zhijie; Cao, Dawei; Wen, Liaoyong; Xu, Rui; Obergfell, Manuel; Mi, Yan; Zhan, Zhibing; Nasori, Nasori; Demsar, Jure; Lei, Yong


    Utilizing plasmonic nanostructures for efficient and flexible conversion of solar energy into electricity or fuel presents a new paradigm in photovoltaics and photoelectrochemistry research. In a conventional photoelectrochemical cell, consisting of a plasmonic structure in contact with a semiconductor, the type of photoelectrochemical reaction is determined by the band bending at the semiconductor/electrolyte interface. The nature of the reaction is thus hard to tune. Here instead of using a semiconductor, we employed a ferroelectric material, Pb(Zr,Ti)O3 (PZT). By depositing gold nanoparticle arrays and PZT films on ITO substrates, and studying the photocurrent as well as the femtosecond transient absorbance in different configurations, we demonstrate an effective charge transfer between the nanoparticle array and PZT. Most importantly, we show that the photocurrent can be tuned by nearly an order of magnitude when changing the ferroelectric polarization in PZT, demonstrating a versatile and tunable system for energy harvesting.

  4. The effect of dust charge fluctuations in the near-Enceladus plasma (United States)

    Yaroshenko, Victoria; Luehr, Hermann

    The geologically active moon Enceladus feeds the most extended, Saturns’ E ring by dust particles and creates a specific multispecies plasma environment -the Enceladus plasma torus. The key process of dust-plasma interactions is dust charging. The grain electrostatic potential in space is usually calculated from the so called orbit-motion limited (OML) model [1]. It is valid for a single particle immersed into collisionless plasmas with Maxwellian electron and ion distributions. Such a parameter regime cannot be directly applied to the conditions relevant for the Enceladus plasma environment and especially, for the dense plume region, where the dust density is high, sometimes even exceeding the plasma number density. Generalizing the OML formalism, we examine several new factors that can significantly affect the equilibrium grain charging: (a) multispecies composition of the core plasma, including hot electrons and newborn cold ions; (b) effect of high dust number density (c) the role of dust size distributions. We also focus on such a specific peculiarity of dust charging as charge fluctuations. Since the grain charges are not fixed and can fluctuate, this introduces the crucial difference between ordinary plasma species (electrons and ions) and charged dust particles. There are two reasons for such fluctuations. The charging of the grains depends on the local plasma characteristics, and thus some temporal or spatial variations in the plasma parameters ultimately modify numbers of charges acquired by a grain. Some of these effects related to the near-Enceladus plasma environment have recently been discussed [2]. A second reason for charge fluctuations is the discrete nature of the charge carriers. Electrons and ions are absorbed or emitted by the grain surface randomly thus leading to stochastic fluctuations of the dust net charge. These fluctuations exist always even in a steady-state uniform plasma, and we discuss the statistical characteristics of random dust

  5. Effects of D-600 on intramembrane charge movement of polarized and depolarized frog muscle fibers. (United States)

    Caputo, C; Bolaños, P


    Intramembrane charge movement has been measured in frog cut skeletal muscle fibers using the triple vaseline gap voltage-clamp technique. Ionic currents were reduced using an external solution prepared with tetraethylammonium to block potassium currents, and O sodium + tetrodotoxin to abolish sodium currents. The internal solution contained 10 mM EGTA to prevent contractions. Both the internal and external solutions were prepared with impermeant anions. Linear capacitive currents were subtracted using the P-P/4 procedure, with the control pulses being subtracted either at very negative potentials, for the case of polarized fibers, or at positive potentials, for the case of depolarized fibers. In 63 polarized fibers dissected from Rana pipiens or Leptodactylus insularis frogs the following values were obtained for charge movement parameters: Qmax = 39 nC/microF, V = 36 mV, k = 18.5 mV. After depolarization we found that the total amount of movable charge was not appreciably reduced, while the voltage sensitivity was much changed. For 10 fibers, in which charge movement was measured at -100 and at 0 mV, Qmax changed from 46 to 41 nC/microF, while V changed from -41 to -103 mV and k changed from 20.5 to 30 mV. Thus membrane depolarization to 0 mV produces a shift of greater than 50 mV in the Q-V relationship and a decrease of the slope. Membrane depolarization to -20 and -30 mV, caused a smaller shift of the Q-V relationship. In normally polarized fibers addition of D-600 at concentrations of 50-100 microM, does not cause important changes in charge movement parameters. However, the drug appears to have a use-dependent effect after depolarization. Thus in depolarized fibers, total charge is reduced by approximately 20%. D-600 causes no further changes in the voltage sensitivity of charge movement in fibers depolarized to 0 mV, while in fibers depolarized to -20 and -30 mV it causes the same effects as that obtained with depolarization to 0 mV. These results are

  6. Electrical charging effects on the sliding friction of a model nano-confined ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Capozza, R.; Vanossi, A. [International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste (Italy); CNR-IOM Democritos National Simulation Center, Via Bonomea 265, 34136 Trieste (Italy); Benassi, A. [CNR-IOM Democritos National Simulation Center, Via Bonomea 265, 34136 Trieste (Italy); Institute for Materials Science and Max Bergmann Center of Biomaterials, TU Dresden, 01062 Dresden (Germany); Tosatti, E. [International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste (Italy); CNR-IOM Democritos National Simulation Center, Via Bonomea 265, 34136 Trieste (Italy); International Centre for Theoretical Physics (ICTP), Strada Costiera 11, 34014 Trieste (Italy)


    Recent measurements suggest the possibility to exploit ionic liquids (ILs) as smart lubricants for nano-contacts, tuning their tribological and rheological properties by charging the sliding interfaces. Following our earlier theoretical study of charging effects on nanoscale confinement and squeezout of a model IL, we present here molecular dynamics simulations of the frictional and lubrication properties of that model under charging conditions. First, we describe the case when two equally charged plates slide while being held together to a confinement distance of a few molecular layers. The shear sliding stress is found to rise strongly and discontinuously as the number of IL layers decreases stepwise. However, the shear stress shows, within each given number of layers, only a weak dependence upon the precise value of the normal load, a result in agreement with data extracted from recent experiments. We subsequently describe the case of opposite charging of the sliding plates and follow the shear stress when the charging is slowly and adiabatically reversed in the course of time, under fixed load. Despite the fixed load, the number and structure of the confined IL layers change with changing charge, and that in turn drives strong friction variations. The latter involves first of all charging-induced freezing of the IL film, followed by a discharging-induced melting, both made possible by the nanoscale confinement. Another mechanism for charging-induced frictional changes is a shift of the plane of maximum shear from mid-film to the plate-film interface, and vice versa. While these occurrences and results invariably depend upon the parameters of the model IL and upon its specific interaction with the plates, the present study helps identifying a variety of possible behavior, obtained under very simple assumptions, while connecting it to an underlying equilibrium thermodynamics picture.

  7. Removal of charged micropollutants from water by ion-exchange polymers -- effects of competing electrolytes. (United States)

    Bäuerlein, Patrick S; Ter Laak, Thomas L; Hofman-Caris, Roberta C H M; de Voogt, Pim; Droge, Steven T J


    A wide variety of environmental compounds of concern, e.g. pharmaceuticals or illicit drugs, are acids or bases that may predominantly be present as charged species in drinking water sources. These charged micropollutants may prove difficult to remove by currently used water treatment steps (e.g. UV/H(2)O(2), activated carbon (AC) or membranes). We studied the sorption affinity of some ionic organic compounds to both AC and different charged polymeric materials. Ion-exchange polymers may be effective as additional extraction phases in water treatment, because sorption of all charged compounds to oppositely charged polymers was stronger than to AC, especially for the double-charged cation metformin. Tested below 1% of the polymer ion-exchange capacity, the sorption affinity of charged micropollutants is nonlinear and depends on the composition of the aqueous medium. Whereas oppositely charged electrolytes do not impact sorption of organic ions, equally charged electrolytes do influence sorption indicating ion-exchange (IE) to be the main sorption mechanism. For the tested polymers, a tenfold increased salt concentration lowered the IE-sorption affinity by a factor two. Different electrolytes affect IE with organic ions in a similar way as inorganic ions on IE-resins, and no clear differences in this trend were observed between the sulphonated and the carboxylated cation-exchanger. Sorption of organic cations is five fold less in Ca(2+) solutions compared to similar concentrations of Na(+), while that of anionic compounds is three fold weaker in SO(4)(2-) solutions compared to equal concentrations of Cl(-). Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Understanding the effects of electronic polarization and delocalization on charge-transport levels in oligoacene systems

    KAUST Repository

    Sutton, Christopher


    Electronic polarization and charge delocalization are important aspects that affect the charge-transport levels in organic materials. Here, using a quantum mechanical/ embedded-charge (QM/EC) approach based on a combination of the long-range corrected omega B97X-D exchange-correlation functional (QM) and charge model 5 (CM5) point-charge model (EC), we evaluate the vertical detachment energies and polarization energies of various sizes of crystalline and amorphous anionic oligoacene clusters. Our results indicate that QM/EC calculations yield vertical detachment energies and polarization energies that compare well with the experimental values obtained from ultraviolet photoemission spectroscopy measurements. In order to understand the effect of charge delocalization on the transport levels, we considered crystalline naphthalene systems with QM regions including one or five-molecules. The results for these systems show that the delocalization and polarization effects are additive; therefore, allowing for electron delocalization by increasing the size of the QM region leads to the additional stabilization of the transport levels. Published by AIP Publishing.

  9. The determination of surface charge on nitrogen-containing reduced graphene oxides and its application to adsorb molybdate

    Energy Technology Data Exchange (ETDEWEB)

    Li, Mingjie, E-mail: [Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Beijing 100190 (China); Research Centre for Process Pollution Control, Beijing 100190 (China); National Engineering Research Center of Distillation Technology, Tianjin University, Tianjin 300072 (China); Liu, Chenming, E-mail: [Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Beijing 100190 (China); Research Centre for Process Pollution Control, Beijing 100190 (China); Cao, Hongbin, E-mail: [Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Beijing 100190 (China); Research Centre for Process Pollution Control, Beijing 100190 (China); Pan, Jiachuan, E-mail: [Syracuse University, Syracuse, NY 13244 (United States); Zhao, He, E-mail: [Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Beijing 100190 (China); Research Centre for Process Pollution Control, Beijing 100190 (China); and others


    To speculate the performance of chemically reduced graphene oxide from different reductants, detailed investigation of chemical structures needs diverse characterizations. Surface charge, mainly resulting from surface functional groups, may provide a facile method to comprehensively predict performance on certain levels. Surface charge of hydrazine-reduced graphene oxide (HrGO) and p-phenylenediamine (p-PDA)-reduced graphene oxide (ArGO) was investigated by cyclic voltammetry. The charge generation mechanism was further analysed by X-ray photoelectron spectroscopy. Electrical impedance spectroscopy was applied to investigate the effect of surface charge on the adsorptive properties. Furthermore, the experiments on MoO{sub 4}{sup 2−} adsorbed by ArGO were carried out at different pH values. Results indicate that the surface charge on ArGO was more positive than that on HrGO, which is mainly due to protonation of amino group. MoO{sub 4}{sup 2−} adsorption experiments indicate that relative positive charge made ArGO more efficient than HrGO to adsorb MoO{sub 4}{sup 2−}. - Highlights: • The p-PDA reduced graphene oxide (ArGO) has positive charge on its surface. • Positive surface charge on ArGO is mainly from the protonation of amine groups. • Positive charge enhances the diffusion and adsorption of negative ions onto ArGO. • The maximum MoO{sub 4}{sup 2−} adsorption capacity of ArGO can reach to 61 mg g{sup −1}.

  10. Special raster scanning for reduction of charging effects in scanning electron microscopy. (United States)

    Suzuki, Kazuhiko; Oho, Eisaku


    A special raster scanning (SRS) method for reduction of charging effects is developed for the field of SEM. Both a conventional fast scan (horizontal direction) and an unusual scan (vertical direction) are adopted for acquiring raw data consisting of many sub-images. These data are converted to a proper SEM image using digital image processing techniques. About sharpness of the image and reduction of charging effects, the SRS is compared with the conventional fast scan (with frame-averaging) and the conventional slow scan. Experimental results show the effectiveness of SRS images. By a successful combination of the proposed scanning method and low accelerating voltage (LV)-SEMs, it is expected that higher-quality SEM images can be more easily acquired by the considerable reduction of charging effects, while maintaining the resolution. © 2013 Wiley Periodicals, Inc.

  11. CHARMM fluctuating charge force field for proteins: I parameterization and application to bulk organic liquid simulations. (United States)

    Patel, Sandeep; Brooks, Charles L


    A first-generation fluctuating charge (FQ) force field to be ultimately applied for protein simulations is presented. The electrostatic model parameters, the atomic hardnesses, and electronegativities, are parameterized by fitting to DFT-based charge responses of small molecules perturbed by a dipolar probe mimicking a water dipole. The nonbonded parameters for atoms based on the CHARMM atom-typing scheme are determined via simultaneously optimizing vacuum water-solute geometries and energies (for a set of small organic molecules) and condensed phase properties (densities and vaporization enthalpies) for pure bulk liquids. Vacuum solute-water geometries, specifically hydrogen bond distances, are fit to 0.19 A r.m.s. error, while dimerization energies are fit to 0.98 kcal/mol r.m.s. error. Properties of the liquids studied include bulk liquid structure and polarization. The FQ model does indeed show a condensed phase effect in the shifting of molecular dipole moments to higher values relative to the gas phase. The FQ liquids also appear to be more strongly associated, in the case of hydrogen bonding liquids, due to the enhanced dipolar interactions as evidenced by shifts toward lower energies in pair energy distributions. We present results from a short simulation of NMA in bulk TIP4P-FQ water as a step towards simulating solvated peptide/protein systems. As expected, there is a nontrivial dipole moment enhancement of the NMA (although the quantitative accuracy is difficult to assess). Furthermore, the distribution of dipole moments of water molecules in the vicinity of the solutes is shifted towards larger values by 0.1-0.2 Debye in keeping with previously reported work. Copyright 2003 Wiley Periodicals, Inc. J Comput Chem 25: 1-15, 2004

  12. Electrical study of trapped charges in nanoscale Ge islands by Kelvin probe force microscopy for nonvolatile memory applications (United States)

    Lin, Z.; Brunkov, P.; Bassani, F.; Bremond, G.


    Isolated Germanium nanoisland on top of silicon dioxide (SiO2) layer has been studied by Kelvin probe force microscopy (KPFM) at room temperature. Different surface potentials between Ge island and SiO2 dielectric layer were directly visualized from the KPFM image. The image contrast greatly increased after electron injection by applying a negative bias of -7 V. The dissipation of injected electrons was evaluated by measuring the surface potential variation due to the leakage of these injected charges. The long retention time of local charges in Ge dot is promising for applications in nonvolatile memories.

  13. Renormalization of effective interactions in a negative charge transfer insulator (United States)

    Seth, Priyanka; Peil, Oleg E.; Pourovskii, Leonid; Betzinger, Markus; Friedrich, Christoph; Parcollet, Olivier; Biermann, Silke; Aryasetiawan, Ferdi; Georges, Antoine


    We compute from first principles the effective interaction parameters appropriate for a low-energy description of the rare-earth nickelate LuNiO3 involving the partially occupied eg states only. The calculation uses the constrained random-phase approximation and reveals that the effective on-site Coulomb repulsion is strongly reduced by screening effects involving the oxygen-p and nickel-t2 g states. The long-range component of the effective low-energy interaction is also found to be sizable. As a result, the effective on-site interaction between parallel-spin electrons is reduced down to a small negative value. This validates effective low-energy theories of these materials that were proposed earlier. Electronic structure methods combined with dynamical mean-field theory are used to construct and solve an appropriate low-energy model and explore its phase diagram as a function of the on-site repulsion and Hund's coupling. For the calculated values of these effective interactions, we find that in agreement with experiments, LuNiO3 is a metal without disproportionation of the eg occupancy when considered in its orthorhombic structure, while the monoclinic phase is a disproportionated insulator.

  14. Strong coupling electrostatics for randomly charged surfaces: antifragility and effective interactions. (United States)

    Ghodrat, Malihe; Naji, Ali; Komaie-Moghaddam, Haniyeh; Podgornik, Rudolf


    We study the effective interaction mediated by strongly coupled Coulomb fluids between dielectric surfaces carrying quenched, random monopolar charges with equal mean and variance, both when the Coulomb fluid consists only of mobile multivalent counterions and when it consists of an asymmetric ionic mixture containing multivalent and monovalent (salt) ions in equilibrium with an aqueous bulk reservoir. We analyze the consequences that follow from the interplay between surface charge disorder, dielectric and salt image effects, and the strong electrostatic coupling that results from multivalent counterions on the distribution of these ions and the effective interaction pressure they mediate between the surfaces. In a dielectrically homogeneous system, we show that the multivalent counterions are attracted towards the surfaces with a singular, disorder-induced potential that diverges logarithmically on approach to the surfaces, creating a singular but integrable counterion density profile that exhibits an algebraic divergence at the surfaces with an exponent that depends on the surface charge (disorder) variance. This effect drives the system towards a state of lower thermal 'disorder', one that can be described by a renormalized temperature, exhibiting thus a remarkable antifragility. In the presence of an interfacial dielectric discontinuity, the singular behavior of counterion density at the surfaces is removed but multivalent counterions are still accumulated much more strongly close to randomly charged surfaces as compared with uniformly charged ones. The interaction pressure acting on the surfaces displays in general a highly non-monotonic behavior as a function of the inter-surface separation with a prominent regime of attraction at small to intermediate separations. This attraction is caused directly by the combined effects from charge disorder and strong coupling electrostatics of multivalent counterions, which dominate the surface-surface repulsion due to

  15. Effect of sodium deprivation on contraction and charge movement in frog skeletal muscle fibres. (United States)

    Garcia, M C; Diaz, A F; Godinez, R; Sanchez, J A


    Measurements of isometric tension were performed in single twitch skeletal muscle fibres and the effect of extracellular Na+ removal on contraction was investigated. Na+ withdrawal brought about an increase in the amplitude of K+ contractures and their time course became faster. The potentiation of K+ contractures depended strongly on extracellular Ca2+ and developed slowly following an exponential time course with a time constant of approximately 8 min. Removal of extracellular Na+ greatly increased the amplitude of caffeine contractures and lowered its threshold: caffeine (0.5 mM) had no effect on resting tension in Ringer's but produced contractures in Na(+)-free solutions. Intramembrane charge movement (charge 1) was monitored in contracting voltage-clamped segments of frog skeletal muscle fibres using the triple-Vaseline-gap technique. Movement of charge 1 did not depend on the presence of extracellular Na+. However, the mechanical threshold decreased by approximately 10 mV at several pulse durations and the charge which produced just detectable contractions decreased by approximately 5 nC microF-1 in the absence of extracellular Na+. Intracellular heparin (40 mg ml-1) increased the mechanical threshold by approximately 20 mV without affecting the movement of charge 1. The effect of Na(+)-free solutions on the mechanical threshold was additive to that of heparin. It is concluded that the effects of Na(+)-withdrawal on contraction take place at a location beyond the voltage sensor of excitation-contraction coupling.

  16. Chemical Vapour Deposition Diamond - Charge Carrier Movement at Low Temperatures and Use in Time-Critical Applications

    CERN Document Server

    Jansen, Hendrik; Pernegger, Heinz

    Diamond, a wide band gap semiconductor with exceptional electrical properties, has found its way in diverse fields of application reaching from the usage as a sensor material for beam loss monitors at particle accelerator facilities, to laser windows, to UV light sensors in space applications, e.g. for space weather forecasting. Though often used at room temperature, little is known about the charge transport in diamond towards liquid helium temperatures. In this work the method of the transient current technique is employed at temperatures between room temperature and 2 K. The temperature and electric field strength dependence of the pulse shape, the charge carrier transit time, the drift velocity, the saturation velocity, and the low-field mobility is measured in detector-grade scCVD diamond. Furthermore, the usability of diamond in time-critical applications is tested, and the main results are presented.

  17. Porous Silicon Structures under action microwave Radiation: Charge Carrier Heating Effects (United States)

    Shatkovskis, Eugenijus; Gradauskas, Jonas; Cesnys, Antanas


    Porous silicon (por-Si) is one of modern nanomaterials, which is intensively investigated recently. The action of microwave radiation is only slightly investigated on por-Si, however. Basically there are papers intended to application of por-Si as substrates in microwave and opto-electronic interconnects. Action microwave radiation (MW) often manifests itself through effects of charge carrier heating in semiconductors. Since the energy quanta of MW radiation are too small to challenge any quantum jumps in common semiconductors, it is likely that carrier heating can be responsible for effects arising in por-Si under MW radiation also. This question is discussed in present contribution based on experimental study of electrical conductivity and electromotive force (emf) in por-Si structures under the action of 10 GHz frequency MW radiation pulses. Two-terminal por-Si containing structures were made by usual technology of electrochemical etching of p-type, 0, 4 Si plates in the HF: Ethanol=1:2 electrolyte. It has been shown that experimentally observed decrease of the resistance of the samples and rise of emf can be explained both assuming concept of hole heating, by MW radiation in fractal-like percolation grid of por-Si structure.

  18. Computational investigation of the effects of perfluorination on the charge-transport properties of polyaromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Cardia, R. [Università degli studi di Cagliari, Dipartimento di Fisica, Cittadella Universitaria, I-09042 Monserrato (Cagliari) (Italy); Istituto Officina dei Materiali (CNR – IOM), UOS di Cagliari, Cittadella Universitaria, I-09042 Monserrato, Cagliari (Italy); Malloci, G., E-mail: [Università degli studi di Cagliari, Dipartimento di Fisica, Cittadella Universitaria, I-09042 Monserrato (Cagliari) (Italy); Bosin, A.; Serra, G. [Università degli studi di Cagliari, Dipartimento di Fisica, Cittadella Universitaria, I-09042 Monserrato (Cagliari) (Italy); Cappellini, G., E-mail: [Università degli studi di Cagliari, Dipartimento di Fisica, Cittadella Universitaria, I-09042 Monserrato (Cagliari) (Italy); Istituto Officina dei Materiali (CNR – IOM), UOS di Cagliari, Cittadella Universitaria, I-09042 Monserrato, Cagliari (Italy)


    We present a systematic computational study of the effects of perfluorination on the charge-transport properties of three homologous classes of polyaromatic hydrocarbons of interest for molecular electronics: acenes, pyrenes, and circumacenes. By means of Density Functional Theory calculations we first obtained the key molecular properties for transport of both holes and electrons. We then used these parameters in the framework of Marcus theory to compare charge-transfer rates in the high temperatures regime for both unsubstituted and perfluorinated molecules. We additionally estimated the relative charge-mobility of each unsubstituted (perfluorinated) molecule with respect to unsubstituted (perfluorinated) pentacene. We found in all cases that perfluorination reduces the charge-transfer rate in absolute terms. This is largely due to the higher values of the molecular reorganization energies predicted for perfluorinated compounds. Interestingly, however, the charge-transfer rates for both holes and electrons of perfluorinated species are remarkably similar, especially for the larger species. In addition, in the case of the larger circumacenes the charge-mobility values relative to pentacene values are found to increase upon perfluorination.

  19. Effect of ion suprathermality on arbitrary amplitude dust acoustic waves in a charge varying dusty plasma (United States)

    Tribeche, Mouloud; Mayout, Saliha; Amour, Rabia


    Arbitrary amplitude dust acoustic waves in a high energy-tail ion distribution are investigated. The effects of charge variation and ion suprathermality on the large amplitude dust acoustic (DA) soliton are then considered. The correct suprathermal ion charging current is rederived based on the orbit motion limited approach. In the adiabatic case, the variable dust charge is expressed in terms of the Lambert function and we take advantage of this transcendental function to show the existence of rarefactive variable charge DA solitons involving cusped density humps. The dust charge variation leads to an additional enlargement of the DA soliton, which is less pronounced as the ions evolve far away from Maxwell-Boltzmann distribution. In the nonadiabatic case, the dust charge fluctuation may provide an alternate physical mechanism causing anomalous dissipation the strength of which becomes important and may prevail over that of dispersion as the ion spectral index κ increases. Our results may provide an explanation for the strong spiky waveforms observed in auroral electric field measurements by Ergun et al. [Geophys. Res. Lett. 25, 2025 (1998)].

  20. Studies of Space Charge Effects in the Proposed CERN PS2

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, Ji; /LBL, Berkeley; Ryne, Robert; /LBL, Berkeley; De Maria, Riccardo; /Brookhaven; Macridin, Alexandru; /Fermilab; Spentzouris, Panagiotis; /Fermilab; Papaphilippou, Yannis; /CERN; Wienands, Ulrich; /SLAC


    A new proton synchrotron, the PS2, is under design study to replace the current proton synchrotron at CERN for the LHC upgrade. Nonlinear space charge effects could cause significant beam emittance growth and particle losses and limit the performance of the PS2. In this paper, we report on studies of the potential space-charge effects at the PS2 using three-dimensional self-consistent macroparticle tracking codes, IMPACT, MaryLie/IMPACT, and Synergia. We will present initial benchmark results among these codes. Effects of space-charge on the emittance growth, especially due to synchrotron coupling, aperture sizes, initial painted distribution, and RF ramping scheme will also be discussed.

  1. Gain length fitting formula for free-electron lasers with strong space-charge effects

    Directory of Open Access Journals (Sweden)

    G. Marcus


    Full Text Available We present a power-fit formula, obtained from a variational analysis using three-dimensional free-electron laser theory, for the gain length of a high-gain free-electron laser’s fundamental mode in the presence of diffraction, uncorrelated energy spread, and longitudinal space-charge effects. The approach is inspired by the work of Xie [Nucl. Instrum. Methods Phys. Res., Sect. A 445, 59 (2000NIMAER0168-900210.1016/S0168-9002(0000114-5], and provides a useful shortcut for calculating the gain length of the fundamental Gaussian mode of a free-electron laser having strong space-charge effects in the 3D regime. The results derived from analytic theory are in good agreement with detailed numerical particle simulations that also include higher-order space-charge effects, supporting the assumptions made in the theoretical treatment and the variational solutions obtained in the single-mode limit.

  2. On the secondary charging effects and structure of mesospheric dust particles impacting on rocket probes

    Energy Technology Data Exchange (ETDEWEB)

    Havnes, O.; Naesheim, L.I. [Inst. of Physics, Univ. of Tromso (Norway)


    The dust probe DUSTY, first launched during the summer of 1994 (flights ECT-02 and ECT-07) from Andoeya Rocket Range, northern Norway, was the first probe to unambiguously detect heavy charged mesospheric aerosols, from hereon referred to as dust. In ECT-02 the probe detected negatively charged dust particles in the height interval of 83 to 88.5 km. In this flight, the lower grid in the detector (Grid 2) measures both positive and negative currents in various regions, and we find that the relationship between the current measurements of Grid 2 and the bottom plate can only be explained by influence from secondary charge production on Grid 2. In ECT-07, which had a large coning, positive currents reaching the top grid of the probe were interpreted as due to the impact of positively charged dust particles. We have now reanalyzed the data from ECT-07 and arrived at the conclusion that the measured positive currents to this grid must have been mainly due to secondary charging effects from the impacting dust particles. The grid consists of a set of parallel wires crossed with an identical set of wires on top of it, and we find that if the observed currents were created from the direct impact of charged dust particles, then they should be very weakly modulated at four times the rocket spin rate {omega}{sub R}. Observations show, however, that the observed currents are strongly modulated at 2{omega}{sub R}. We cannot reproduce the observed large modulations of the impact currents in the dust layer if the currents are due only to the transfer of the charges on the impacted dust particles. Based on the results of recent ice cluster impact secondary charging experiments by Tomsic (2003), which found that a small fraction of the ice clusters, when impacting with nearly grazing incidence, carried away one negative charge - 1e, we have arrived at the conclusion that similar, but significantly more effective, charging effects must be predominantly responsible for the positive

  3. Investigation of Laser Peening Effects on Hydrogen Charged Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Zaleski, Tania M. [San Jose State Univ., CA (United States)


    Hydrogen-rich environments such as fuel cell reactors can exhibit damage caused by hydrogen permeation in the form of corrosion cracking by lowering tensile strength and decreasing material ductility. Coatings and liners have been investigated, but there were few shot-peening or laser peening studies referenced in the literature with respect to preventing hydrogen embrittlement. The surface compressive residual stress induced by laser peening had shown success in preventing stress corrosion cracking (SCC) for stainless steels in power plants. The question arose if the residual stresses induced by laser peening could delay the effects of hydrogen in a material. This study investigated the effect of laser peening on hydrogen penetration into metal alloys. Three areas were studied: laser peening, hydrogenation, and hydrogen detection. This study demonstrated that laser peening does not reduce the hydrogen permeation into a stainless steel surface nor does it prevent hydrogen embrittlement. The effect of laser peening to reduce hydrogen-assisted fatigue was unclear.

  4. Charge-Separation Kinetics of Photoexcited Oxygen Vacancies in ZnO Nanowire Field-Effect Transistors (United States)

    Lu, Ming-Pei; Chen, Chieh-Wei; Lu, Ming-Yen


    Photoinduced atomic structural transitions of negative-U defects: neutral oxygen vacancies (VO 0 ), accompanied by lattice relaxation, can form ionized 1 + and 2 + vacancy defects in ZnO materials, giving rise to an optoelectronic phenomenon named "persistent photoconductivity," thereby limiting the applications of ZnO materials in optoelectronic fields. Nevertheless, very little is known about the kinetics of the separation-recombination interactions between an electron and an ionized oxygen vacancy, constituting a photoexcited charge pair, in nanoscale ZnO material systems, especially when considering the effect of electric fields. In this report, we describe the charge-separation kinetics of photoexcited VO 0 defects in ZnO nanowire (NW) field-effect transistor (FET) systems, examined through modulation of the surface electric field of the ZnO NW. We apply oxygen plasma treatment to tailor the doping concentration within the ZnO NWs with the goal of modulating the electric field within their surface space-charge layers. X-ray photoelectron spectroscopy and low-frequency current-noise spectroscopy are applied to identify the change in the density of oxygen-vacancy defects near the NW surface after oxygen plasma treatment. A model describing the initial stage of the photoconductance responses associated with the formation of the photoinduced ionized 1 + state of the oxygen-vacancy defects (VO + ) in the fully depleted ZnO NW FETs in the low-photoconductance regime upon UV excitation is proposed to extract the charge-separation probabilities of the photoexcited electron/VO + pair. Accordingly, the charge-separation probability increases from approximately 0.0012 to 0.042 upon increasing the electric field at the NW surface from approximately 7.5 ×106 to 5.0 ×107 V m-1 . Moreover, we employ modified Braun empirical theory to model the effect of the electric field on the charge-separation behavior of photoexcited electron/VO + pairs in ZnO NWs, obtaining a

  5. Effects of radiation on charge-coupled devices (United States)

    Carnes, J. E.; Cope, A. D.; Rockett, L. R.; Schlesier, K. M.


    The effects of 1 MeV electron irradiation upon the performance of two phase, polysilicon aluminum gate CCDs are reported. Both n- and p-surface channel and n-buried channel devices are investigated using 64- and 128-stage line arrays. Characteristics measured as a function of radiation dose include: Transfer inefficiency, threshold voltage, field effect mobility, interface state density, full well signal level and dark current. Surface channel devices are found to degrade considerably at less than 10 to the 5th power rads (Si) due to the large increase in fast interface state density caused by radiation. Buried channel devices maintain efficient operation to the highest dose levels used.

  6. Controllable Charge Transfer in Ag-TiO2 Composite Structure for SERS Application

    Directory of Open Access Journals (Sweden)

    Yaxin Wang


    Full Text Available The nanocaps array of TiO2/Ag bilayer with different Ag thicknesses and co-sputtering TiO2-Ag monolayer with different TiO2 contents were fabricated on a two-dimensional colloidal array substrate for the investigation of Surface enhanced Raman scattering (SERS properties. For the TiO2/Ag bilayer, when the Ag thickness increased, SERS intensity decreased. Meanwhile, a significant enhancement was observed when the sublayer Ag was 10 nm compared to the pure Ag monolayer, which was ascribed to the metal-semiconductor synergistic effect that electromagnetic mechanism (EM provided by roughness surface and charge-transfer (CT enhancement mechanism from TiO2-Ag composite components. In comparison to the TiO2/Ag bilayer, the co-sputtered TiO2-Ag monolayer decreased the aggregation of Ag particles and led to the formation of small Ag particles, which showed that TiO2 could effectively inhibit the aggregation and growth of Ag nanoparticles.

  7. Effect of radiative cooling on collapsing charged grains

    Indian Academy of Sciences (India)

    Thus, numerical picture suggests that most of the radiative effects dominate at large implying condensation and structure formation down to much shorter scales (nearly by a factor of 2) than otherwise possible by purely. Jeans mode (curve 1). Physically, gravitational condensation is inhibited by the 'thermal pressure' (set up ...

  8. Analysing degradation effects in charge-redistribution SAR ADCs

    NARCIS (Netherlands)

    Khan, M.A.; Kerkhoff, Hans G.


    Aging-sensitive technology nodes that are resulting in performance degradations in their electronic system implementations require aging simulations in advance for a more dependable design. Simulating time-domain aging effects in these electronic systems, especially in complex analog and


    Surface site (>SOH group) acidity reactions require expressions of the form: Ka = [>SOHn-1(z-1)]aH+EXP(-DG/RT)/[>SOHnz] (where all variables have their usual meaning). One can rearrange this expression to generate an effective acidity constant historically defined as: Qa = Ka...

  10. Gate-Sensing Coherent Charge Oscillations in a Silicon Field-Effect Transistor. (United States)

    Gonzalez-Zalba, M Fernando; Shevchenko, Sergey N; Barraud, Sylvain; Johansson, J Robert; Ferguson, Andrew J; Nori, Franco; Betz, Andreas C


    Quantum mechanical effects induced by the miniaturization of complementary metal-oxide-semiconductor (CMOS) technology hamper the performance and scalability prospects of field-effect transistors. However, those quantum effects, such as tunneling and coherence, can be harnessed to use existing CMOS technology for quantum information processing. Here, we report the observation of coherent charge oscillations in a double quantum dot formed in a silicon nanowire transistor detected via its dispersive interaction with a radio frequency resonant circuit coupled via the gate. Differential capacitance changes at the interdot charge transitions allow us to monitor the state of the system in the strong-driving regime where we observe the emergence of Landau-Zener-Stückelberg-Majorana interference on the phase response of the resonator. A theoretical analysis of the dispersive signal demonstrates that quantum and tunneling capacitance changes must be included to describe the qubit-resonator interaction. Furthermore, a Fourier analysis of the interference pattern reveals a charge coherence time, T2 ≈ 100 ps. Our results demonstrate charge coherent control and readout in a simple silicon transistor and open up the possibility to implement charge and spin qubits in existing CMOS technology.

  11. Charge Equalization Controller Algorithm for Series-Connected Lithium-Ion Battery Storage Systems: Modeling and Applications

    Directory of Open Access Journals (Sweden)

    Mahammad A. Hannan


    Full Text Available This study aims to develop an accurate model of a charge equalization controller (CEC that manages individual cell monitoring and equalizing by charging and discharging series-connected lithium-ion (Li-ion battery cells. In this concept, an intelligent control algorithm is developed to activate bidirectional cell switches and control direct current (DC–DC converter switches along with pulse width modulation (PWM generation. Individual models of an electric vehicle (EV-sustainable Li-ion battery, optimal power rating, a bidirectional flyback DC–DC converter, and charging and discharging controllers are integrated to develop a small-scale CEC model that can be implemented for 10 series-connected Li-ion battery cells. Results show that the charge equalization controller operates at 91% efficiency and performs well in equalizing both overdischarged and overcharged cells on time. Moreover, the outputs of the CEC model show that the desired balancing level occurs at 2% of state of charge difference and that all cells are operated within a normal range. The configuration, execution, control, power loss, cost, size, and efficiency of the developed CEC model are compared with those of existing controllers. The proposed model is proven suitable for high-tech storage systems toward the advancement of sustainable EV technologies and renewable source of applications.

  12. Charge Storage, Conductivity and Charge Profiles of Insulators as Related to Spacecraft Charging (United States)

    Dennison, J. R.; Swaminathan, Prasanna; Frederickson, A. R.


    Dissipation of charges built up near the surface of insulators due to space environment interaction is central to understanding spacecraft charging. Conductivity of insulating materials is key to determine how accumulated charge will distribute across the spacecraft and how rapidly charge imbalance will dissipate. To understand these processes requires knowledge of how charge is deposited within the insulator, the mechanisms for charge trapping and charge transport within the insulator, and how the profile of trapped charge affects the transport and emission of charges from insulators. One must consider generation of mobile electrons and holes, their trapping, thermal de-trapping, mobility and recombination. Conductivity is more appropriately measured for spacecraft charging applications as the "decay" of charge deposited on the surface of an insulator, rather than by flow of current across two electrodes around the sample. We have found that conductivity determined from charge storage decay methods is 102 to 104 smaller than values obtained from classical ASTM and IEC methods for a variety of thin film insulating samples. For typical spacecraft charging conditions, classical conductivity predicts decay times on the order of minutes to hours (less than typical orbit periods); however, the higher charge storage conductivities predict decay times on the order of weeks to months leading to accumulation of charge with subsequent orbits. We found experimental evidence that penetration profiles of radiation and light are exceedingly important, and that internal electric fields due to charge profiles and high-field conduction by trapped electrons must be considered for space applications. We have also studied whether the decay constants depend on incident voltage and flux or on internal charge distributions and electric fields; light-activated discharge of surface charge to distinguish among differing charge trapping centers; and radiation-induced conductivity. Our

  13. Gas-surface dynamics and charging effects during plasma processing of semiconductors (United States)

    Hwang, Gyeong Soon

    energy ions and lowering the electron temperature helps decrease the impact of charging. In this numerical work, we found that charging damage is a strong function of the shape of feature profiles evolving during etching as well as the extent of microloading. Charging damage may occur by means of surging currents and steady-state currents. Although the lack of experimental evidence still leaves room for other mechanisms, the experimental observations of the notching behavior suggest strongly that the notching effect is closely connected with pattern-dependent charging. Our charging simulations have demonstrated that the potential difference between the trench bottom and the poly-Si gate is mainly responsible for notching by deflecting incoming ions. The study of the mask charging effect on feature profile evolution during chlorine plasma etching of silicon suggests that differential charging at mask sidewalls could significantly influence the evolution of etch profiles under typical plasma conditions when the mask thickness is large. At moderate mask aspect ratios, the local electric fields created by mask charging cause to the deflection of ions to the trench sidewalls, increasing the flux of energetic particles scattered into the base of the trench sidewalls and thus aggravating microtrenching. On the other hand, at high mask aspect ratios, mask charging results in focusing incoming ions onto the center of the trench bottom, causing a more rounded trench bottom without microtrenching. (Abstract shortened by UMI.)

  14. Resistive Micromegas for sampling calorimetry, a study of charge-up effects

    Energy Technology Data Exchange (ETDEWEB)

    Chefdeville, M., E-mail: [LAPP, Université de Savoie, CNRS/IN2P3, Annecy-Le-Vieux (France); Karyotakis, Y. [LAPP, Université de Savoie, CNRS/IN2P3, Annecy-Le-Vieux (France); Geralis, T. [INP, NCSR Demokritos, Athens (Greece); Titov, M. [IRFU, Saclay CEA, Gif-sur-Yvette (France)


    Micromegas, as a proportional and compact gaseous detector, is well suited for sampling calorimetry. The limitation of occasional sparking has now been lifted by means of resistive electrodes but at the cost of current-dependent charge-up effects. These effects are studied in this contribution, with an emphasis on gain variations during operation at high particle rate and under heavy ionisation. Results are reproduced by a simple model of charging-up which will be used for detector design optimisation in the future.

  15. Multiphasic modeling of charged solute transport across articular cartilage: Application of multi-zone finite-bath model. (United States)

    Arbabi, Vahid; Pouran, Behdad; Weinans, Harrie; Zadpoor, Amir A


    Charged and uncharged solutes penetrate through cartilage to maintain the metabolic function of chondrocytes and to possibly restore or further breakdown the cartilage tissue in different stages of osteoarthritis. In this study the transport of charged solutes across the various zones of cartilage was quantified, taken into account the physicochemical interactions between the solute and the cartilage constituents. A multiphasic finite-bath finite element (FE) model was developed to simulate equine cartilage diffusion experiments that used a negatively charged contrast agent (ioxaglate) in combination with serial micro-computed tomography (micro-CT) to measure the diffusion. By comparing the FE model with the experimental data both the diffusion coefficient of ioxaglate and the fixed charge density (FCD) were obtained. In the multiphasic model, cartilage was divided into multiple (three) zones to help understand how diffusion coefficient and FCD vary across cartilage thickness. The direct effects of charged solute-FCD interaction on diffusion were investigated by comparing the diffusion coefficients derived from the multiphasic and biphasic-solute models. We found a relationship between the FCD obtained by the multiphasic model and ioxaglate partitioning obtained from micro-CT experiments. Using our multi-zone multiphasic model, diffusion coefficient of the superficial zone was up to ten-fold higher than that of the middle zone, while the FCD of the middle zone was up to almost two-fold higher than that of the superficial zone. In conclusion, the developed finite-bath multiphasic model provides us with a non-destructive method by which we could obtain both diffusion coefficient and FCD of different cartilage zones. The outcomes of the current work will also help understand how charge of the bath affects the diffusion of a charged molecule and also predict the diffusion behavior of a charged solute across articular cartilage. Copyright © 2016 Elsevier Ltd. All

  16. Electrostatic potential of a charged ring: Applications to elliptic integral identities (United States)

    Noh, Heung-Ryoul


    We present a proof of a transformation identity of a complete elliptic integral of the first kind, presented in a recent publication [O. Ciftja et al., Eur. J. Phys. 30, 623 (2009)], where it was derived from an analytical solution of the electrostatic potential due to a uniformly charged ring. In addition, by calculating the electrostatic potential due to a charged ring with a sinusoidal charge distribution, we obtain a new mathematical identity for the complete elliptic integral of the second kind. We show that these two identities can be derived from the existing mathematical identities of elliptic integrals, proving them in a direct manner.

  17. Anomalous doping effects on charge transport in graphene nanoribbons. (United States)

    Biel, Blanca; Blase, X; Triozon, François; Roche, Stephan


    We present first-principles calculations of quantum transport in chemically doped graphene nanoribbons with a width of up to 4 nm. The presence of boron and nitrogen impurities is shown to yield resonant backscattering, whose features are strongly dependent on the symmetry and the width of the ribbon, as well as the position of the dopants. Full suppression of backscattering is obtained on the pi-pi* plateau when the impurity preserves the mirror symmetry of armchair ribbons. Further, an unusual acceptor-donor transition is observed in zigzag ribbons. These unconventional doping effects could be used to design novel types of switching devices.

  18. Gold plasmonic effects on charge transport through single molecule junctions (United States)

    Adak, Olgun; Venkataraman, Latha


    We study the impact of surface plasmon polaritons, the coupling of electromagnetic waves to collective electron oscillations on metal surfaces, on the conductance of single-molecule junctions. We use a scanning-tunneling microscope based break junction setup that is built into an optical microscope to form molecular junctions. Coherent 685nm light is used to illuminate the molecular junctions formed with 4,4'-bipyridine with diffraction limited focusing performance. We employ a lock-in type technique to measure currents induced by light. Furthermore, the thermal expansion due to laser heating is mimicked by mechanically modulating inter-electrode separation. For each junction studied, we measure current, and use AC techniques to determine molecular junction resonance levels and coupling strengths. We use a cross correlations analysis technique to analyze and compare the effect of light to that of the mechanical modulation. Our results show that junction transmission characteristics are not altered under illumination, within the resolution of our instrument. We argue that photo-currents measured with lock-in techniques in these kinds of structures are due to thermal effects. This work was funded by the Center for Re-Defining Photovoltaic Efficiency through Molecule Scale Control, an EFRC funded by the US Department of Energy, Office of Basic Energy Sciences under Contract No. DESC0001085.

  19. Non-targeted effects induced by high LET charged particles (United States)

    Hei, Tom K.; Chai, Yunfei; Hamada, Nobuyuki; Kakinuma, Shizuko; Uchihori, Yukio

    Radiation-induced non-targeted response represents a paradigm shift in our understanding of the radiobiological effects of ionizing radiation in that extranuclear and extracellular effects may also contribute to the final biological consequences of exposure to low doses of radiation. Using the gpt delta transgenic mouse model, there is evidence that irradiation of a small area (1 cm by 1 cm) of the lower abdominal area of animals with a 5 Gy dose of X-rays induced cyclooxygenase-2 as well as deletion mutations in the out-of-field lung tissues of the animals. The mutation correlated with an increase in prostaglandin levels in the bystander lung tissues and with an increase in the level of 8-hydroxydeoxyguanosine (8-OHdG), an oxidative DNA damage marker. An increase in COX-2 level was also detected in the out-of-field lung tissues of animals similarly exposed to high LET argon and carbon ions accelerated at the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences in Japan. These results provide the first evidence that the COX-2 -related pathway, which is essential in mediating cellular inflammatory response, is the critical signaling link for the non-targeted, bystander phenomenon. A better understanding of the cellular and molecular mechanisms of the non-targeted, out of field phenomenon together with evidence of their occurrence in vivo will allow us to formulate a more accurate assessment of radiation risk.

  20. Tridodecylamine, an efficient charge control agent in non-polar media for electrophoretic inks application (United States)

    Noel, Amélie; Mirbel, Déborah; Cloutet, Eric; Fleury, Guillaume; Schatz, Christophe; Navarro, Christophe; Hadziioannou, Georges; CyrilBrochon


    In order to obtain efficient electrophoretic inks, Tridodecylamine (Dod3N), has been studied as charge control agent (CCA) in a non-polar paraffin solvent (Isopar G) for various inorganic pigments (TiO2 and Fe2O3). All hydrophobic mineral oxides, i.e. treated with octyltrimethoxysilane (C8) or dodecyltrimethoxysilane (C12), were found to be negatively charged in presence of Dod3N. The electrophoretic mobilities of inorganic pigments seemed to be strongly dependent of their isoelectric point (IEP) and also of the concentration of dod3N with an optimum range between 10 and 20 mM depending on the pigments. Finally, an electrophoretic ink constituted of hydrophobic mineral oxides in presence of Dod3N was tested in a device. Its efficiency as charge control agent to negatively charge hydrophobic particles was confirmed through good optical properties and fast response time (220 ms at 200 kV m-1).

  1. Effects of High Charge Densities in Multi-GEM Detectors

    CERN Document Server

    Franchino, S.; Hall-Wilton, R.; Muller, H.; Oliveri, E.; Pfeiffer, D.; Resnati, F.; Ropelewski, L.; Van Stenis, M.; Streli, C.; Thuiner, P.; Veenhof, R.


    A comprehensive study, supported by systematic measurements and numerical computations, of the intrinsic limits of multi-GEM detectors when exposed to very high particle fluxes or operated at very large gains is presented. The observed variations of the gain, of the ion back-flow, and of the pulse height spectra are explained in terms of the effects of the spatial distribution of positive ions and their movement throughout the amplification structure. The intrinsic dynamic character of the processes involved imposes the use of a non-standard simulation tool for the interpretation of the measurements. Computations done with a Finite Element Analysis software reproduce the observed behaviour of the detector. The impact of this detailed description of the detector in extreme conditions is multiple: it clarifies some detector behaviours already observed, it helps in defining intrinsic limits of the GEM technology, and it suggests ways to extend them.

  2. The Effects of Stoichiometry on the Optical Properties of PTZ-TCNQ Charge Transfer Crystals (United States)

    Stone, Iris; Joshi, Jaydeep; Smith, Robert; Melis, Scott; van Keuren, Edward; Vora, Patrick

    Charge transfer (CT) crystals are two-component organic materials formed by stacked pairs of donor and acceptor molecules. Depending on the choice of donor and acceptor molecules it is possible to achieve semiconducting, insulating, or metallic characteristics, making the CT crystal platform potentially transformative for applications in low-cost flexible electronics. The use of phenothiazine (PTZ) donors and tetracyanoquinodimethane (TCNQ) acceptors is predicted to result in a semiconducting state with high electron and hole mobilities, properties that are ideal for ambipolar transistors. Here, we seek to understand the effect of stoichiometry on the optical and electronic properties of PTZ:TCNQ CT crystals by comparing nanowires with 1:1 stoichiometry to a novel 3:1 stoichiometry using temperature-dependent optical spectroscopy. Ensemble photoluminescence and absorption measurements indicate that a CT state forms in the 1:1 sample, whereas the 3:1 sample exhibits weaker coupling between TCNQ and PTZ. These results support a strong correlation between stoichiometry and optical properties. Our observations give important insight into how the intermolecular coupling varies with stoichiometry and are crucial to future efforts to realize an organic ambipolar transistor.

  3. Fabrication of Al2O3 Nano-Structure Functional Film on a Cellulose Insulation Polymer Surface and Its Space Charge Suppression Effect

    Directory of Open Access Journals (Sweden)

    Jian Hao


    Full Text Available Cellulose insulation polymer (paper/pressboard has been widely used in high voltage direct current (HVDC transformers. One of the most challenging issues in the insulation material used for HVDC equipment is the space charge accumulation. Effective ways to suppress the space charge injection/accumulation in insulation material is currently a popular research topic. In this study, an aluminium oxide functional film was deposited on a cellulose insulation pressboard surface using reactive radio frequency (RF magnetron sputtering. The sputtered thin film was characterized by the scanning electron microscopy/energy dispersive spectrometer (SEM/EDS, X-ray photoelectron spectroscopy (XPS, and X-ray diffraction (XRD. The influence of the deposited functional film on the dielectric properties and the space charge injection/accumulation behaviour was investigated. A preliminary exploration of the space charge suppression effect is discussed. SEM/EDS, XPS, and XRD results show that the nano-structured Al2O3 film with amorphous phase was successfully fabricated onto the fibre surface. The cellulose insulation pressboard surface sputtered by Al2O3 film has lower permittivity, conductivity, and dissipation factor values in the lower frequency (<103 Hz region. The oil-impregnated sputtered pressboard presents an apparent space-charge suppression effect. Compared with the pressboard sputtered with Al2O3 film for 90 min, the pressboard sputtered with Al2O3 film for 60 min had a better space charge suppression effect. Ultra-small Al2O3 particles (<10 nm grew on the surface of the larger nanoparticles. The nano-structured Al2O3 film sputtered on the fibre surface could act as a functional barrier layer for suppression of the charge injection and accumulation. This study offers a new perspective in favour of the application of insulation pressboard with a nano-structured function surface against space charge injection/accumulation in HVDC equipment.

  4. Studies of Polyelectrolyte Solutions V. Effects of Counterion Binding by Polyions of Varying Charge Density and Constant Degree of Polymerization

    National Research Council Canada - National Science Library

    Nordmeier, Eckhard


    The effect of the charge density on the behaviour of polyelectrolytes in contact with counterions was studied by activity measurements, Donnan dialysis, dye-spectrophotometry, and potentiometric titration...

  5. Predicting and rationalizing the effect of surface charge distribution and orientation on nano-wire based FET bio-sensors

    DEFF Research Database (Denmark)

    De Vico, L.; Iversen, L.; Sørensen, Martin Hedegård


    A single charge screening model of surface charge sensors in liquids (De Vico et al., Nanoscale, 2011, 3, 706-717) is extended to multiple charges to model the effect of the charge distributions of analyte proteins on FET sensor response. With this model we show that counter-intuitive signal...... changes (e.g. a positive signal change due to a net positive protein binding to a p-type conductor) can occur for certain combinations of charge distributions and Debye lengths. The new method is applied to interpret published experimental data on Streptavidin (Ishikawa et al., ACS Nano, 2009, 3, 3969...

  6. 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)


    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.

  7. CrossRef Space-charge effects in Penning ion traps

    CERN Document Server

    Porobić, T; Breitenfeldt, M; Couratin, C; Finlay, P; Knecht, A; Fabian, X; Friedag, P; Fléchard, X; Liénard, E; Ban, G; Zákoucký, D; Soti, G; Van Gorp, S; Weinheimer, Ch; Wursten, E; Severijns, N


    The influence of space-charge on ion cyclotron resonances and magnetron eigenfrequency in a gas-filled Penning ion trap has been investigated. Off-line measurements with View the MathML source using the cooling trap of the WITCH retardation spectrometer-based setup at ISOLDE/CERN were performed. Experimental ion cyclotron resonances were compared with ab initio Coulomb simulations and found to be in agreement. As an important systematic effect of the WITCH experiment, the magnetron eigenfrequency of the ion cloud was studied under increasing space-charge conditions. Finally, the helium buffer gas pressure in the Penning trap was determined by comparing experimental cooling rates with simulations.


    Directory of Open Access Journals (Sweden)

    V. V. Klubovich


    Full Text Available The paper describes the effect of ultrasound activation of dolomite, which is used for producing refractory material by the SHS method, on the final product. X-ray investigation has demonstrated that ultrasound activation of the initial charge brings about changes in the phase composition of the synthesized product.

  9. Effects of Confinement on Microstructure and Charge Transport in High Performance Semicrystalline Polymer Semiconductors

    KAUST Repository

    Himmelberger, Scott


    The film thickness of one of the most crystalline and highest performing polymer semiconductors, poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b] thiophene) (PBTTT), is varied in order to determine the effects of interfaces and confinement on the microstructure and performance in organic field effect transistors (OFETs). Crystalline texture and overall film crystallinity are found to depend strongly on film thickness and thermal processing. The angular distribution of crystallites narrows upon both a decrease in film thickness and thermal annealing. These changes in the film microstructure are paired with thin-film transistor characterization and shown to be directly correlated with variations in charge carrier mobility. Charge transport is shown to be governed by film crystallinity in films below 20 nm and by crystalline orientation for thicker films. An optimal thickness is found for PBTTT at which the mobility is maximized in unannealed films and where mobility reaches a plateau at its highest value for annealed films. The effects of confinement on the morphology and charge transport properties of poly(2,5-bis(3-tetradecylthiophen-2-yl) thieno[3,2-b]thiophene) (PBTTT) are studied using quantitative X-ray diffraction and field-effect transistor measurements. Polymer crystallinity is found to limit charge transport in the thinnest films while crystalline texture and intergrain connectivity modulate carrier mobility in thicker films. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Effect of dust size distribution and dust charge fluctuation on dust ion ...

    Indian Academy of Sciences (India)

    The effects of dust size distribution and dust charge fluctuation of dust grains on the small but finite amplitude nonlinear dust ion-acoustic shock waves, in an unmagnetized multi-ion dusty plasma which contains negative ions, positive ions and electrons, are studied in this paper. A Burgers equation and its stationary ...

  11. Within-Individual Variation in Preferences Equity Effects of Congestion Charges

    DEFF Research Database (Denmark)

    Borjesson, Maria; Cherchi, Elisabetta; Bierlaire, Michel


    that variation in VTT between observed trips reflects the variation in the average VTT between individuals, which is usually made in equity analyses, will over-state the between-individual variation. The results suggest that if intraindividual variation in preferences is not taken into account, the negative...... equity effects of congestion charges are likely to be overestimated....

  12. Crystal structure and charge distribution of pyrazine: effects of extinction, thermal diffuse scattering and series termination

    NARCIS (Netherlands)

    de With, G.; Harkema, Sybolt; Feil, D.


    The crystal structure and electronic charge distribution of pyrazine (1,4-diazabenzene) has been determined at 184 K by X-ray methods. The structural results of Wheatley [Acta Cryst. (1957), 10, 182-187] have been confirmed. A clear indication of bonding effects is obtained. Neither positional and

  13. Gate-bias assisted charge injection in organic field-effect transistors

    NARCIS (Netherlands)

    Brondijk, J. J.; Torricelli, F.; Smits, E. C. P.; Blom, P. W. M.; de Leeuw, D. M.

    The charge injection barriers in organic field-effect transistors (OFETs) seem to be far less critical as compared to organic light-emitting diodes (OLEDs). Counter intuitively, we show that the origin is image-force lowering of the barrier due to the gate bias at the source contact, although the

  14. Gate-bias assisted charge injection in organic field-effect transistors

    NARCIS (Netherlands)

    Brondijk, J.J.; Torricelli, F.; Smits, E.C.P.; Blom, P.W.M.; Leeuw, D.M. de


    The charge injection barriers in organic field-effect transistors (OFETs) seem to be far less critical as compared to organic light-emitting diodes (OLEDs). Counter intuitively, we show that the origin is image-force lowering of the barrier due to the gate bias at the source contact, although the

  15. Charge transport in dual-gate organic field-effect transistors

    NARCIS (Netherlands)

    Brondijk, J.J.; Spijkman, M.; Torricelli, F.; Blom, P.W.M.; Leeuw, D.M. de


    The charge carrier distribution in dual-gate field-effect transistors is investigated as a function of semiconductor thickness. A good agreement with 2-dimensional numerically calculated transfer curves is obtained. For semiconductor thicknesses larger than the accumulation width, two spatially

  16. Effect of current density on electron beam induced charging in MgO

    Energy Technology Data Exchange (ETDEWEB)

    Boughariou, Aicha [LaMaCoP, Universite de Sfax, Faculte des Sciences, 3038 Sfax (Tunisia)]. E-mail:; Hachicha, Olfa [LaMaCoP, Universite de Sfax, Faculte des Sciences, 3038 Sfax (Tunisia); Kallel, Ali [LaMaCoP, Universite de Sfax, Faculte des Sciences, 3038 Sfax (Tunisia); Blaise, Guy [LPS, Universite Paris-Sud XI, Batiment 510, Orsay 91405 (France)


    It is well known that the presence of space charge in an insulator is correlated with an electric breakdown. Many studies have been carried out on the experimental characterization of space charges. In this paper, we outline the dependence on the current density of the charge-trapping phenomenon in magnesium oxide. Our study was performed with a dedicated scanning electron microscope (SEM) on the electrical property evolution of surface of magnesium oxide (1 0 0) (MgO) single crystal, during a 1.1, 5 and 30 keV electron irradiation. The types of charges trapped on the irradiated areas and the charging kinetics are determined by measuring the total secondary electron emission (SEE) {sigma} during the injection process by means of two complementary detectors. At low energies 1.1 and 5 keV, two different kinds of self-regulated regime ({sigma} = 1) were observed as a function of current density. At 30 keV energy, the electron emission appears to be stimulated by the current density, due to the Poole-Frenkel effect.

  17. Carrier polarity engineering in carbon nanotube field-effect transistors by induced charges in polymer insulator (United States)

    Aikawa, Shinya; Kim, Sungjin; Thurakitseree, Theerapol; Einarsson, Erik; Inoue, Taiki; Chiashi, Shohei; Tsukagoshi, Kazuhito; Maruyama, Shigeo


    We present that the electrical conduction type in carbon nanotube field-effect transistors (CNT-FETs) can be converted by induced charges in a polyvinyl alcohol (PVA) insulator. When the CNT channels are covered with pure PVA, the FET characteristics clearly change from unipolar p-type to ambipolar. The addition of ammonium ions (NH4+) in the PVA leads to further conversion to unipolar n-type conduction. The capacitance - voltage characteristics indicate that a high density of positive charges is induced at the PVA/SiO2 interface and within the bulk PVA. Electrons are electrostatically accumulated in the CNT channels due to the presence of the positive charges, and thus, stable n-type conduction of PVA-coated CNT-FETs is observed, even under ambient conditions. The mechanism for conversion of the conduction type is considered to be electrostatic doping due to the large amount of positive charges in the PVA. A blue-shift of the Raman G-band peak was observed for CNTs coated with NH4+-doped PVA, which corresponds to unipolar n-type CNT-FET behavior. These results confirm that carrier polarity engineering in CNT-FETs can be achieved with a charged PVA passivation layer.

  18. Direct femtosecond observation of charge carrier recombination in ternary semiconductor nanocrystals: The effect of composition and shelling

    KAUST Repository

    Bose, Riya


    Heavy-metal free ternary semiconductor nanocrystals are emerging as key materials in photoactive applications. However, the relative abundance of intra-bandgap defect states and lack of understanding of their origins within this class of nanocrystals are major factors limiting their applicability. To remove these undesirable defect states which considerably shorten the lifetimes of photogenerated excited carriers, a detailed understanding about their origin and nature is required. In this report, we monitor the ultrafast charge carrier dynamics of CuInS2 (CIS), CuInSSe (CISSe), and CuInSe2 (CISe) nanocrystals, before and after ZnS shelling, using state-of-the-art time-resolved laser spectroscopy with broadband capabilities. The experimental results demonstrate the presence of both electron and hole trapping intra-bandgap states in the nanocrystals which can be removed significantly by ZnS shelling, and the carrier dynamics is slowed down. Another important observation remains the reduction of carrier lifetime in the presence of Se, and the shelling strategy is observed to be less effective at suppressing trap states. This study provides quantitative physical insights into the role of anion composition and shelling on the charge carrier dynamics in ternary CIS, CISSe, and CISe nanocrystals which are essential to improve their applicability for photovoltaics and optoelectronics.

  19. STM visualisation of counterions and the effect of charges on self-assembled monolayers of macrocycles

    Directory of Open Access Journals (Sweden)

    Tibor Kudernac


    Full Text Available Despite their importance in self-assembly processes, the influence of charged counterions on the geometry of self-assembled organic monolayers and their direct localisation within the monolayers has been given little attention. Recently, various examples of self-assembled monolayers composed of charged molecules on surfaces have been reported, but no effort has been made to prove the presence of counterions within the monolayer. Here we show that visualisation and exact localisation of counterions within self-assembled monolayers can be achieved with scanning tunnelling microscopy (STM. The presence of charges on the studied shape-persistent macrocycles is shown to have a profound effect on the self-assembly process at the liquid–solid interface. Furthermore, preferential adsorption was observed for the uncharged analogue of the macrocycle on a surface.

  20. Effect of the size of charged spherical macroparticles on their electrostatic interaction in an equilibrium plasma

    Energy Technology Data Exchange (ETDEWEB)

    Filippov, A. V., E-mail:; Derbenev, I. N. [State Research Center of the Russian Federation, Troitsk Institute for Innovation and Fusion Research (Russian Federation)


    The effect of the size of two charged spherical macroparticles on their electrostatic interaction in an equilibrium plasma is analyzed within the linearized Poisson–Botzmann model. It is established that, under the interaction of two charged dielectric macroparticles in an equilibrium plasma, the forces acting on each particle turn out to be generally unequal. The forces become equal only in the case of conducting macroparticles or in the case of dielectric macroparticles of the same size and charge. They also turn out to be equal when the surface potentials of the macroparticles remain constant under the variation of interparticle distances. Formulas are proposed that allow one to calculate the interaction force with a high degree of accuracy under the condition that the radii of macroparticles are much less than the screening length, which is usually satisfied in experiments with dusty plasmas.

  1. Space Charge Effects and Advanced Modelling for CERN Low Energy Machines

    CERN Document Server

    AUTHOR|(CDS)2088716; Rumolo, Giovanni

    The strong space charge regime of future operation of CERN’s circular particle accelerators is investigated and mitigation strategies are developed in the framework of the present thesis. The intensity upgrade of the injector chain of Large Hadron Collider (LHC) prepares the particle accelerators to meet the requirements of the High-Luminosity LHC project. Producing the specified characteristics of the future LHC beams imperatively relies on injecting brighter bunches into the Proton Synchrotron Booster (PSB), the downstream Proton Synchrotron (PS) and eventually the Super Proton Synchrotron (SPS). The increased brightness, i.e. bunch intensity per transverse emittance, entails stronger beam self-fields which can lead to harmful interaction with betatron resonances. Possible beam emittance growth and losses as a consequence thereof threaten to degrade the beam brightness. These space charge effects are partly mitigated by the upgrade of the PSB and PS injection energies. Nevertheless, the space charge tune ...

  2. The electro-mechanical effect from charge dynamics on polymeric insulation lifetime

    Directory of Open Access Journals (Sweden)

    H. Alghamdi


    Full Text Available For polymeric material used as electrical insulation, the presence of space charges could be the consequence of material degradations that are thermally activated but increased by the application of an electric field. The dynamics of space charge, therefore, can be potentially used to characterize the material. In this direction, a new aging model in which parameters have clear physical meanings has been developed and applied to the material to extrapolate the lifetime. The kinetic equation has been established based on charge trapping and detrapping of the injected charge from the electrodes. The local electromechanical energy stored in the region surrounding the trap is able to reduce the trap-depth with a value related to the electric field. At a level where the internal electric field exceeds the detrapping field in the material, an electron can be efficiently detrapped and the released energy from detrapping process can cause a weak bond or chain scission i.e. material degradation. The model has been applied to the electro-thermally aged low density polyethylene film samples, showing well fitted result, as well as interesting relationships between parameter estimates and insulation morphology.

  3. The electro-mechanical effect from charge dynamics on polymeric insulation lifetime

    Energy Technology Data Exchange (ETDEWEB)

    Alghamdi, H., E-mail: [Faculty of Physical Sciences and Engineering, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Faculty of Engineering, Najran University, Najran, P.O.Box 1988 (Saudi Arabia); Chen, G.; Vaughan, A. S. [Faculty of Physical Sciences and Engineering, University of Southampton, Southampton, SO17 1BJ (United Kingdom)


    For polymeric material used as electrical insulation, the presence of space charges could be the consequence of material degradations that are thermally activated but increased by the application of an electric field. The dynamics of space charge, therefore, can be potentially used to characterize the material. In this direction, a new aging model in which parameters have clear physical meanings has been developed and applied to the material to extrapolate the lifetime. The kinetic equation has been established based on charge trapping and detrapping of the injected charge from the electrodes. The local electromechanical energy stored in the region surrounding the trap is able to reduce the trap-depth with a value related to the electric field. At a level where the internal electric field exceeds the detrapping field in the material, an electron can be efficiently detrapped and the released energy from detrapping process can cause a weak bond or chain scission i.e. material degradation. The model has been applied to the electro-thermally aged low density polyethylene film samples, showing well fitted result, as well as interesting relationships between parameter estimates and insulation morphology.

  4. The effect of charge on the release kinetics from polysaccharide–nanoclay composites

    Energy Technology Data Exchange (ETDEWEB)

    Buffa, Stefano Del; Grifoni, Emanuele; Ridi, Francesca, E-mail:; Baglioni, Piero, E-mail: [University of Florence, Department of Chemistry “Ugo Schiff” and CSGI (Italy)


    The objective of this study was to integrate inorganic halloysite nanotubes (HNT) with chitosan and hyaluronic acid to obtain hybrid nanocomposites with opposing charges and to investigate their potential in the controlled release of drug model probes. Two oppositely charged polysaccharides, chitosan and hyaluronic acid, were selected for their biocompatibility and their importance in biomedical applications. The high surface area and the hollow nanometric-sized lumen of HNT allowed for the efficient loading of rhodamine 110 and carboxyfluorescein, used as models for oppositely charged drugs. In the case of chitosan, the preparation of the nanocomposite was carried out exploiting the electrostatic interaction between the polymer and HNT in water, while with hyaluronic acid, a covalent functionalization strategy was employed to couple the polymer with the clay. Nanocomposites were characterized with thermal, microscopic, and spectroscopic techniques, and the release kinetics of the model compounds was assessed by fluorescence measurements. The release curves were fitted with a model able to account for the desorption process from the external and the internal halloysite surfaces. The results show that both polymeric coatings alter the release of the probes, indicating a key role of both charge and coating composition on the initial and final amount of released dye, as well as on the rate of the desorption process.

  5. Combined effects of space charge and energetic disorder on photocurrent efficiency loss of field-dependent organic photovoltaic devices (United States)

    Yoon, Sangcheol; Park, Byoungchoo; Hwang, Inchan


    The loss of photocurrent efficiency by space-charge effects in organic solar cells with energetic disorder was investigated to account for how energetic disorder incorporates space-charge effects, utilizing a drift-diffusion model with field-dependent charge-pair dissociation and suppressed bimolecular recombination. Energetic disorder, which induces the Poole-Frenkel behavior of charge carrier mobility, is known to decrease the mobility of charge carriers and thus reduces photovoltaic performance. We found that even if the mobilities are the same in the absence of space-charge effects, the degree of energetic disorder can be an additional parameter affecting photocurrent efficiency when space-charge effects occur. Introducing the field-dependence parameter that reflects the energetic disorder, the behavior of efficiency loss with energetic disorder can differ depending on which charge carrier is subject to energetic disorder. While the energetic disorder that is applied to higher-mobility charge carriers decreases photocurrent efficiency further, the efficiency loss can be suppressed when energetic disorder is applied to lower-mobility charge carriers.

  6. Planning Minimum Interurban Fast Charging Infrastructure for Electric Vehicles: Methodology and Application to Spain

    Directory of Open Access Journals (Sweden)

    Antonio Colmenar-Santos


    Full Text Available The goal of the research is to assess the minimum requirement of fast charging infrastructure to allow country-wide interurban electric vehicle (EV mobility. Charging times comparable to fueling times in conventional internal combustion vehicles are nowadays feasible, given the current availability of fast charging technologies. The main contribution of this paper is the analysis of the planning method and the investment requirements for the necessary infrastructure, including the definition of the Maximum Distance between Fast Charge (MDFC and the Basic Highway Charging Infrastructure (BHCI concepts. According to the calculations, distance between stations will be region-dependent, influenced primarily by weather conditions. The study considers that the initial investment should be sufficient to promote the EV adoption, proposing an initial state-financed public infrastructure and, once the adoption rate for EVs increases, additional infrastructure will be likely developed through private investment. The Spanish network of state highways is used as a case study to demonstrate the methodology and calculate the investment required. Further, the results are discussed and quantitatively compared to other incentives and policies supporting EV technology adoption in the light-vehicle sector.

  7. Secondary radiation measurements for particle therapy applications: charged particles produced by 4He and 12C ion beams in a PMMA target at large angle. (United States)

    Rucinski, Antoni; Battistoni, Giuseppe; Collamati, Francesco; De Lucia, Erika; Faccini, Riccardo; Frallicciardi, Paola Maria; Mancini-Terracciano, Carlo; Marafini, Michela; Mattei, Ilaria; Muraro, Silvia; Paramatti, Riccardo; Piersanti, Luca; Pinci, Davide; Russomando, Andrea; Sarti, Alessio; Sciubba, Adalberto; Solfaroli Camillocci, Elena; Toppi, Marco; Traini, Giacomo; Voena, Cecilia; Patera, Vincenzo


    Proton and Carbon ion beams are used in the clinical practice for external radiotherapy treatments achieving, for selected indications, promising and superior clinical results with respect to X-ray based radiotherapy. Other ions, like 4He are recently being considered as projectiles in particle therapy centres and might represent a good compromise between the linear energy transfer and the radiobiological effectiveness of 12C ion and proton beams allowing improved tumour control probability and minimising normal tissue complication probability. All the currently used p, 4He and 12C ion beams allow to achieve sharp dose gradients on the boundary of the target volume, however the accurate dose delivery is more sensitive to the patient positioning and to anatomical variations with respect to photon therapy. This requires beam range and/or dose release measurement during patient irradiation and therefore the development of dedicated monitoring techniques. All the proposed methods make use of the secondary radiation created by the beam interaction with the patient and, in particular, in case of 12C ion beams are able to exploits also the significant charged radiation component. Measurements performed to characterise the charged secondary radiation created by 12C and 4He particle therapy beams are reported. Charged secondary yields, energy spectra and emission profiles produced in poly-methyl methacrylate (PMMA) target by 4He and 12C beams of different therapeutic energies were measured at 60° and 90° with respect to the primary beam direction. The secondary yield of protons produced along the primary beam path in PMMA target was obtained. The energy spectra of charged secondaries were obtained from time-of-flight information, whereas the emission profiles were reconstructed exploiting tracking detector information. Obtained measurements are in agreement with results reported in literature and suggests the feasibility of range monitoring based on charged secondary

  8. Research on the application of PPP model in the Chinese construction and operation of new energy vehicle charging facilities (United States)

    Zhu, Liping


    New energy car charging equipment is the development and popularization of new energy vehicles. It has the nature of quasi-public goods. Due to the large number of construction projects, wide distribution, big investment, it needs huge sums of money. PPP mode is a new financing model and has the inherent driving force to lead the idea the technology and the system innovation. The government and the social subject cooperate on the basis of the spirit of contract thus achieve benefit sharing. This mode effectively improve the operation of new energy vehicle charging facilities operating efficiency

  9. Effect of ion compensation of the beam space charge on gyrotron operation

    Energy Technology Data Exchange (ETDEWEB)

    Fokin, A. P.; Glyavin, M. Yu. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Nusinovich, G. S. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742-3511 (United States)


    In gyrotrons, the coherent radiation of electromagnetic waves takes place when the cyclotron resonance condition between the wave frequency and the electron cyclotron frequency or its harmonic holds. The voltage depression caused by the beam space charge field changes the relativistic cyclotron frequency and, hence, can play an important role in the beam-wave interaction process. In long pulse and continuous-wave regimes, the beam space charge field can be partially compensated by the ions, which appear due to the beam impact ionization of neutral molecules of residual gases in the interaction space. In the present paper, the role of this ion compensation of the beam space charge on the interaction efficiency is analyzed. We also analyze the effect of the electron velocity spread on the limiting currents and discuss some effects restricting the ion-to-beam electron density ratio in the saturation stage. It is shown that the effect of the ion compensation on the voltage depression caused by the beam space charge field can cause significant changes in the efficiency of gyrotron operation and, in some cases, even result in the break of oscillations.

  10. Study of the impurity composition and effective plasma charge in the GOL-3 facility

    Energy Technology Data Exchange (ETDEWEB)

    Sorokina, N. V., E-mail:; Burdakov, A. V.; Ivanov, I. A.; Polosatkin, S. V.; Postupaev, V. V.; Rovenskikh, A. F.; Shoshin, A. A. [Russian Academy of Sciences, Budker Institute of Nuclear Physics, Siberian Branch (Russian Federation)


    Heating and confinement of plasma in a multimirror magnetic configuration have been studied at the GOL-3 facility (Budker Institute of Nuclear Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk). The experiments are aimed at estimating the densities and charge states of the main impurities in the GOL-3 plasma and determining their contribution to the effective plasma charge. Plasma with a density of ∼10{sup 15} cm{sup −3} was heated by a relativistic electron beam (1 MeV, 8 μs, ⩽200 kJ). At the end of electron beam injection, the plasma temperature reached 1 keV. The densities of impurities were determined using VUV and visible spectroscopy, as well as mass spectrometry of the residual vacuum. To determine the effective plasma charge, the experimental data were compared with the results of numerical simulations of the ionization balance of impurities. It is shown that the effective plasma charge calculated with allowance for the contributions from the main impurities does not exceed Z{sub eff} = 1.8, which cannot explain the experimentally observed improved confinement of low-density plasma.

  11. Application of charge-dissipation material in MEBES phase-shift mask fabrication (United States)

    Tan, Zoilo C. H.; Sauer, Charles A.


    Several charge dissipation materials were evaluated for their ability to improve the overlay accuracy during phase shift mask (PSM) registered writing on a MEBES system. These included an organic conductive polymer and a number of thin inorganic films, which were applied above or below the resist on a coated mask. When used with the resists, all conductive materials evaluated were capable of providing adequate charge dissipation during registered writing. Overlay accuracy of mean + 3 sigma

  12. A 128-channel picoammeter system and its application on charged particle beam current distribution measurements. (United States)

    Yu, Deyang; Liu, Junliang; Xue, Yingli; Zhang, Mingwu; Cai, Xiaohong; Hu, Jianjun; Dong, Jinmei; Li, Xin


    A 128-channel picoammeter system is constructed based on instrumentation amplifiers. Taking advantage of a high electric potential and narrow bandwidth in DC energetic charged beam measurements, a current resolution better than 5 fA can be achieved. Two sets of 128-channel strip electrodes are implemented on printed circuit boards and are employed for ion and electron beam current distribution measurements. Tests with 60 keV O(3+) ions and 2 keV electrons show that it can provide exact boundaries when a positive charged particle beam current distribution is measured.

  13. Effect of Induced Charge on the Passivity and Passivity Breakdown of 304LN Stainless Steels

    Directory of Open Access Journals (Sweden)

    Gargi Roy Chowdhury


    Full Text Available Passivity breakdown of stainless steel by pitting in chloride environment is believed to occur at point at zero charge (pzc. So, the nature and quantity of charge on the surface plays a very important role on the breakdown of passivity, as chloride ion adsorption depends on that. In this work a DC potential was maintained between aluminium and graphite electrodes, and the aluminium electrode, in turn, was kept in the vicinity of the working electrode in the potentiostatic circuit. Both positive and negative polarity was applied on aluminium to attract or repel chloride ions in the vicinity of the working electrode. Chloride adsorption pattern on the stainless steel electrode got drastically altered due to application of DC potential on the aluminium-graphite circuit.

  14. Studies of the effect of charged hadrons on lead tungstate crystals

    CERN Document Server

    Nessi-Tedaldi, Francesca


    Scintillating crystals are used for calorimetry in several high-energy physics experiments. For some of them, performance has to be ensured in difficult operating conditions, like a high radiation environment, very large particle fluxes and high collision rates. Results are presented here from a thorough series of measurements concerning mainly the effect of charged hadrons on lead tungstate. It is also shown how these results can be used to predict the effect on crystals due to a given flux of particles.

  15. Unconventional Current Scaling and Edge Effects for Charge Transport through Molecular Clusters

    DEFF Research Database (Denmark)

    Obersteiner, Veronika; Huhs, Georg; Papior, Nick Rübner


    -size islands. On the basis of first-principles charge-transport simulations, we explain why the scaling of the conductivity of a junction has to be highly non-linear in the number of molecules it contains. Moreover, transport through molecular clusters is found to be highly inhomogeneous with pronounced edge...... effects determined by molecules in locally different electrostatic environments. These effects are most pronounced for comparably small clusters, but electrostatic considerations show that they prevail also for more extended systems....

  16. High-Performance Nonvolatile Organic Field-Effect Transistor Memory Based on Organic Semiconductor Heterostructures of Pentacene/P13/Pentacene as Both Charge Transport and Trapping Layers. (United States)

    Li, Wen; Guo, Fengning; Ling, Haifeng; Zhang, Peng; Yi, Mingdong; Wang, Laiyuan; Wu, Dequn; Xie, Linghai; Huang, Wei


    Nonvolatile organic field-effect transistor (OFET) memory devices based on pentacene/N,N'-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (P13)/pentacene trilayer organic heterostructures have been proposed. The discontinuous n-type P13 embedded in p-type pentacene layers can not only provide electrons in the semiconductor layer that facilitates electron trapping process; it also works as charge trapping sites, which is attributed to the quantum well-like pentacene/P13/pentacene organic heterostructures. The synergistic effects of charge trapping in the discontinuous P13 and the charge-trapping property of the poly(4-vinylphenol) (PVP) layer remarkably improve the memory performance. In addition, the trilayer organic heterostructures have also been successfully applied to multilevel and flexible nonvolatile memory devices. The results provide a novel design strategy to achieve high-performance nonvolatile OFET memory devices and allow potential applications for different combinations of various organic semiconductor materials in OFET memory.

  17. Observation and applications of single-electron charge signals in the XENON100 experiment

    NARCIS (Netherlands)

    Aprile, E.; et al., [Unknown; Alfonsi, M.; Colijn, A.P.; Decowski, M.P.


    The XENON100 dark matter experiment uses liquid xenon in a time projection chamber (TPC) to measure xenon nuclear recoils resulting from the scattering of dark matter weakly interacting massive particles (WIMPs). In this paper, we report the observation of single-electron charge signals which are

  18. Simple DCM or CRM analog peak current controller for HV capacitor charge-discharge applications

    DEFF Research Database (Denmark)

    Trintis, Ionut; Dimopoulos, Emmanouil; Munk-Nielsen, Stig


    This paper presents a simple analog current controller suitable for buck and boost converter topologies. The controller operates in DCM or CRM, depending on the setup. The experimental results are presented to validate the proposed controller functionality for a high voltage capacitor charge...

  19. Epoxy Based Nanodielectrics for High Voltage DC Applications : Synthesis, Dielectric Properties and Space Charge Dynamics

    NARCIS (Netherlands)

    Smit, J.J.; Andritsch, T.M.

    Main goal of the research described in this PhD thesis was to determine the influences of filler size, material and distribution on the DC breakdown strength, permittivity and space charge behaviour of nanocomposites. This should lay the groundwork for tailored insulation materials for HVDC

  20. Epoxy Based Nanodielectrics for High Voltage DC Applications : Synthesis, Dielectric Properties and Space Charge Dynamics

    NARCIS (Netherlands)

    Andritsch, T.M.


    Main goal of the research described in this PhD thesis was to determine the influences of filler size, material and distribution on the DC breakdown strength, permittivity and space charge behaviour of nanocomposites. This should lay the groundwork for tailored insulation materials for HVDC

  1. Charge-sharing SAR ADCs for low-voltage low-power applications

    CERN Document Server

    Rabuske, Taimur


    This book introduces readers to the potential of charge-sharing (CS) successive approximation register (SAR) analog-to-digital converters (ADCs), while providing extensive analysis of the factors that limit the performance of the CS topology. The authors present guidelines and useful techniques for mitigating the limitations of the architecture, while focusing on the implementation under restricted power budgets and voltage supplies.

  2. Controlling Charge and Current Neutralization of an Ion Beam Pulse in a Background Plasma by Application of a Small Solenoidal Magnetic Field

    Energy Technology Data Exchange (ETDEWEB)

    Kaganovich, I. D.; Startsev, E. A.; Sefkow, A. B.; Davidson, R. C.


    Propagation of an intense charged particle beam pulse through a background plasma is a common problem in astrophysics and plasma applications. The plasma can effectively neutralize the charge and current of the beam pulse, and thus provides a convenient medium for beam transport. The application of a small solenoidal magnetic field can drastically change the self-magnetic and self-electric fields of the beam pulse, thus allowing effective control of the beam transport through the background plasma. An analytical model is developed to describe the self-magnetic field of a finite-length ion beam pulse propagating in a cold background plasma in a solenoidal magnetic field. The analytical studies show that the solenoidal magnetic field starts to influence the self-electric and self-magnetic fields when ωce ≥ ωpeβb, where ωce = eΒ/mec is the electron gyrofrequency, ωpe is the electron plasma frequency, and βb = Vb/c is the ion beam velocity relative to the speed of light. This condition typically holds for relatively small magnetic fields (about 100G). Analytical formulas are derived for the effective radial force acting on the beam ions, which can be used to minimize beam pinching. The results of analytical theory have been verified by comparison with the simulation results obtained from two particle-in-cell codes, which show good agreement.

  3. Controlling Charge and Current Neutralization of an Ion Beam Pulse in a Background Plasma by Application of a Solenoidal Magnetic Field I: Weak Magnetic Field Limit

    Energy Technology Data Exchange (ETDEWEB)

    Kaganovich, I. D., Startsev, E. A., Sefkow, A. B., Davidson, R. C.


    Propagation of an intense charged particle beam pulse through a background plasma is a common problem in astrophysics and plasma applications. The plasma can effectively neutralize the charge and current of the beam pulse, and thus provides a convenient medium for beam transport. The application of a small solenoidal magnetic field can drastically change the self-magnetic and self- electric fields of the beam pulse, thus allowing effective control of the beam transport through the background plasma. An analytic model is developed to describe the self-magnetic field of a finite- length ion beam pulse propagating in a cold background plasma in a solenoidal magnetic field. The analytic studies show that the solenoidal magnetic field starts to infuence the self-electric and self-magnetic fields when ωce > ωpeβb, where ωce = eβ/mec is the electron gyrofrequency, ωpe is the electron plasma frequency, and βb = Vb/c is the ion beam velocity relative to the speed of light. This condition typically holds for relatively small magnetic fields (about 100G). Analytical formulas are derived for the effective radial force acting on the beam ions, which can be used to minimize beam pinching. The results of analytic theory have been verified by comparison with the simulation results obtained from two particle-in-cell codes, which show good agreement.

  4. Chiral vortical effect from the compactified D4-branes with smeared D0-brane charge

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Chao; Chen, Yidian [Institute of High Energy Physics, Chinese Academy of Sciences,Beijing 100049 (China); Huang, Mei [Institute of High Energy Physics, Chinese Academy of Sciences,Beijing 100049 (China); University of Chinese Academy of Sciences,Beijing 100049 (China); Theoretical Physics Center for Science Facilities, Chinese Academy of Sciences,Beijing 100049 (China)


    By using the boundary derivative expansion formalism of fluid/gravity correspondence, we study the chiral vortical effect from the compactified D4-branes with smeared D0-brane charge. This background corresponds to a strongly coupled, nonconformal relativistic fluid with a conserved vector current. The presence of the chiral vortical effect is induced by the addition of a Chern-Simons term in the bulk action. Except that the non-dissipative anomalous viscous coefficient and the sound speed rely only on the chemical potential, most of the other thermal and hydrodynamical quantities of the first order depend both on the temperature and the chemical potential. According to our result, the way that the chiral vortical effect coefficient depends on the chemical potential seems irrelevant with whether the relativistic fluid is conformal or not. Stability analysis shows that this anomalous relativistic fluid is stable and the doping of the smeared D0-brane charge will slow down the sound speed.

  5. Discrete and modal focusing effects: principles and applications

    DEFF Research Database (Denmark)

    Stamate, Eugen


    Charge flux distribution on the surface of biased electrodes of different geometries immersed in a plasma is investigated by three-dimensional simulations and experiments. It is demonstrated that the sheath surrounding the electrodes that interface insulators acts as an electrostatic lens, focusing...... results in the formation of certain ‘modal spots’ and/or ‘modal lines’. Several phenomenological aspects and potential applications are reviewed and further discussed, including charge focusing by a three-dimensional plasma–sheath–lens, ion dose uniformity during plasma immersion ion implantation, mass...... the charges to distinct locations on the electrode surface depending on the entrance coordinates at the sheath edge. Two focusing effects are identified. Discrete focusing leads to the formation of a passive surface of no ion impact, near the edge of the electrodes interfacing insulators. Modal focusing...

  6. Effects of the Coastal Park Environment Attributes on Its Admission Fee Charges

    Directory of Open Access Journals (Sweden)

    Wang Erda


    Full Text Available In this paper, we investigate the effect of those recognized nature-and-activity-based attributes on the level of park’s admission fee charges using a panel data of 29 coastal recreation parks in Dalian city of China. A total of seven different Hedonic pricing model specifications are used in the estimating process. The results indicate that a numerous attributes have statistically significant effects (α≤ 0.10 on the level of park admission fee charges. In terms of the economic valuation, the marine sightseeing results in the highest value of Marginal Willingness to Pay (MWTP of $6.4 as its quality rank improves to a designated higher level. As expected that the park congestion has a negative effect on the MWTP (-$0.47 and overall park’s rankings have a positive effect ($0.05 on park’s MWTP. However, many recreation activities accommodated by the park sites exhibit a relatively weak effect on the park entrance fee charges. One possible reason is perhaps owing to the single admission package fee policy adopted by the park management..

  7. The effects of tetracaine on charge movement in fast twitch rat skeletal muscle fibres. (United States)

    Hollingworth, S; Marshall, M W; Robson, E


    1. The effects of tetracaine, a local anaesthetic that inhibits muscle contraction, on membrane potential and intramembrane charge movements were investigated in fast twitch rat muscle fibres (extensor digitorum longus). 2. The resting membrane potentials of surface fibres from muscles bathed in isotonic Ringer solution containing 2 mM-tetracaine were well maintained, but higher concentrations of tetracaine caused a time-dependent fall of potential. Muscle fibres bathed in hypertonic solutions containing 2 mM-tetracaine were rapidly depolarized. In both isotonic and hypertonic solutions, the depolarizing effect of tetracaine could not be reversed. 3. Charge movement measurements were made using the middle-of-the-fibre voltage clamp technique. The voltage dependence of charge movements measured in cold isotonic solutions was well fitted by a Boltzmann distribution (Q(V) = Qmax/(1 + exp(-(V-V)/k] where Qmax = 37.3 +/- 2.8 nC muF-1, V = -17.9 +/- 1.2 mV and k = 12.6 +/- 0.8 mV (n = 6, 2 degrees C; means +/- S.E. of means). Similar values were obtained when 2 mM-tetracaine was added to the isotonic bathing fluid (Qmax = 40.6 +/- 2.3 nC microF-1, V = -14.1 +/- 1.3 mV, k = 15.3 +/- 0.8 mV; n = 8, 2 degrees C). 4. Charge movements measured around mechanical threshold in muscle fibres bathed in hypertonic solutions were reduced when 2 mM-tetracaine was added to the bathing fluid. The tetracaine-sensitive component of charge was well fitted with an unconstrained Boltzmann distribution which gave: Qmax = 7.5 nC microF-1, V = -46.5 mV, k = 5.5 mV. The e-fold rise of the foot of the curve was 9.3 mV.

  8. Effects of Electric Vehicle Fast Charging on Battery Life and Vehicle Performance

    Energy Technology Data Exchange (ETDEWEB)

    Matthew Shirk; Jeffrey Wishart


    As part of the U.S. Department of Energy’s Advanced Vehicle Testing Activity, four new 2012 Nissan Leaf battery electric vehicles were instrumented with data loggers and operated over a fixed on-road test cycle. Each vehicle was operated over the test route, and charged twice daily. Two vehicles were charged exclusively by AC level 2 EVSE, while two were exclusively DC fast charged with a 50 kW charger. The vehicles were performance tested on a closed test track when new, and after accumulation of 50,000 miles. The traction battery packs were removed and laboratory tested when the vehicles were new, and at 10,000-mile intervals. Battery tests include constant-current discharge capacity, electric vehicle pulse power characterization test, and low peak power tests. The on-road testing was carried out through 70,000 miles, at which point the final battery tests were performed. The data collected over 70,000 miles of driving, charging, and rest are analyzed, including the resulting thermal conditions and power and cycle demands placed upon the battery. Battery performance metrics including capacity, internal resistance, and power capability obtained from laboratory testing throughout the test program are analyzed. Results are compared within and between the two groups of vehicles. Specifically, the impacts on battery performance, as measured by laboratory testing, are explored as they relate to battery usage and variations in conditions encountered, with a primary focus on effects due to the differences between AC level 2 and DC fast charging. The contrast between battery performance degradation and the effect on vehicle performance is also explored.

  9. Negative Resistance Effect and Charge Transfer Mechanisms in the lon Beam Deposited Diamond Like Carbon Superlattices

    Directory of Open Access Journals (Sweden)



    Full Text Available In the present study DLC:SiOx/DLC/DLC:SiOx/nSi and DLC:SiOx/DLC/DLC:SiOx/pSi structures were fabricated by ion beam deposition using a closed drift ion source. Current-voltage (I-V characteristics of the multilayer samples were measured at room temperature. The main charge transfer mechanisms were considered. Unstable negative resistance effect was observed for some DLC:SiOx/DLC/DLC:SiOx/nSi and DLC:SiOx/DLC/DLC:SiOx/pSi structures. In the case of the diamond like carbon superlattices fabricated on nSi it was observed only during the first measurement. In the case of the some DLC:SiOx/DLC/DLC:SiOx/pSi negative resistance "withstood" several measurements. Changes of the charge carrier mechanisms were observed along with the dissapear of the negative resistance peaks. It seems, that in such a case influence of the bulk related charge transfer mechanisms such as Poole-Frenkel emission increased, while the influence of the contact limited charge transfer mechanisms such as Schottky emission decreased. Observed results were be explained by current flow through the local microconducting channels and subsequent destruction of the localized current pathways as a result of the heating by flowing electric current.

  10. Microfluidic Investigation of the Effect of Liposome Surface Charge on Drug Delivery in Microcirculation. (United States)

    D'Apolito, Rosa; Bochicchio, Sabrina; Dalmoro, Annalisa; Barba, Anna Angela; Guido, Stefano; Tomaiuolo, Giovanna


    Nano-carrier drug transport in blood microcirculation is one of the hotspots of current research in drug development due to many advantages over traditional therapies, such as reduced sideeffects, target delivery, controlled release, improved pharmacokinetics and therapeutic index. Despite the substantial efforts made in the design of nanotherapeutics, the big majority of the used strategies failed to overcome the biological barriers to drug transport encountered in human microvasculature, such as transport by blood flow via the microcirculatory network and margination, the mechanism according to which particles migrate along vessel radius to the wall. In fact, drug transport efficiency in microvasculature is affected by both the particulate nature of blood and drug carrier properties, such as size, shape and surface charge. In this work, the effect of the surface charge of liposomes on their margination in blood flow in microcapillaries was experimentally evaluated. By high-speed video microscopy and image analysis it was found that the two custom-made liposomes (one neuter and the other positively charged) tend to drift laterally, moving towards the wall and accumulating in the cell-free layer. In particular, neuter and cationic liposomes showed a comparable margination propensity, suggesting that the presence of blood cells governs the flow behavior independently on liposome surface charge. Copyright© Bentham Science Publishers; For any queries, please email at

  11. The Effect of Surface Charge Saturation on Heat-induced Aggregation of Firefly Luciferase. (United States)

    Gharanlar, Jamileh; Hosseinkhani, Saman; Sajedi, Reza H; Yaghmaei, Parichehr


    We present here the effect of firefly luciferase surface charge saturation and the presence of some additives on its thermal-induced aggregation. Three mutants of firefly luciferase prepared by introduction of surface Arg residues named as 2R, 3R and 5R have two, three and five additional arginine residues substituted at their surface compared to native luciferase; respectively. Turbidimetric study of heat-induced aggregation indicates that all three mutants were reproducibly aggregated at higher rates relative to wild type in spite of their higher thermostability. Among them, 2R had most evaluated propensity to heat-induced aggregation. Therefore, the hydrophilization followed by appearing of more substituted arginine residues with positive charge on the firefly luciferase surface was not reduced its thermal aggregation. Nevertheless, at the same condition in the presence of charged amino acids, e.g. Arg, Lys and Glu, as well as a hydrophobic amino acid, e.g. Val, the heat-induced aggregation of wild type and mutants of firefly luciferases was markedly decelerated than those in the absence of additives. On the basis of obtained results it seems, relinquishment of variety in charge of amino acid side chains, they via local interactions with proteins cause to decrease rate and extent of their thermal aggregation. © 2015 The American Society of Photobiology.

  12. Proliposome powders for enhanced intestinal absorption and bioavailability of raloxifene hydrochloride: effect of surface charge. (United States)

    Velpula, Ashok; Jukanti, Raju; Janga, Karthik Yadav; Sunkavalli, Sharath; Bandari, Suresh; Kandadi, Prabhakar; Veerareddy, Prabhakar Reddy


    The primary goal of the present study was to investigate the combined prospective of proliposomes and surface charge for the improved oral delivery of raloxifene hydrochloride (RXH). Keeping this objective, the present systematic study was focused to formulate proliposomes by varying the ratio of hydrogenated soyphosphatidylcholine and cholesterol. Furthermore, to assess the role of surface charge on improved absorption of RXH, anionic and cationic vesicles were prepared using dicetyl phosphate and stearylamine, respectively. The formulations were characterized for size, zeta potential and entrapment efficiency. The improved dissolution characteristics assessed from dissolution efficiency, mean dissolution rate were higher for proliposome formulations. The solid state characterization studies indicate the transformation of native crystalline form of the drug to amorphous and/or molecular state. The higher effective permeability coefficient and fraction absorbed in humans extrapolated from in situ single-pass intestinal absorption study data in rats provide an insight on the potential of proliposomes and cationic surface charge for augment in absorption across gastro intestinal barrier. To draw the conclusions, in vivo pharmacokinetic study carried out in rats indicate a threefold enhancement in the rate and extent of absorption of RXH from cationic proliposome formulation which unfurl the potential of proliposomes and role of cationic charge for improved oral delivery of RXH.

  13. Effect of timing of psychiatry consultation on length of pediatric hospitalization and hospital charges. (United States)

    Bujoreanu, Simona; White, Matthew T; Gerber, Bradley; Ibeziako, Patricia


    The purpose of this study was to evaluate the impact of timing of a psychiatry consultation during pediatric hospitalization on length of hospital stay and total hospitalization charges. The charts of 279 pediatric patients (totaling 308 consultations) referred to the psychiatry consultation liaison service at a freestanding tertiary pediatric hospital between January 1, 2010, and June 30, 2010 were retrospectively analyzed. The variables analyzed included the following: patient demographic characteristics; dates of admission, psychiatric consultation, and discharge; psychiatric diagnoses based on the psychiatric diagnostic evaluation; psychiatric treatment disposition; and illness severity and total charges associated with the medical stay. Earlier psychiatry consultation was associated with shorter length of stay and lower hospitalization charges after adjusting for psychiatric functioning, physical illness severity, and psychiatric disposition. Poorer psychiatric functioning and milder physical illness were associated with shorter referral time. Timely involvement of psychiatry consultation services during a medical or surgical hospitalization was associated with reductions in length of stay and total hospital charges in pediatric settings. These findings have important effects on quality of care via decreasing burden on the patient and family and on the medical system resources. Educating pediatric health care providers about the importance of early psychiatry consultation regardless of physical illness severity or psychiatric acuity will likely improve resource management for patients and hospitals. Copyright © 2015 by the American Academy of Pediatrics.

  14. Study of the Effects of the Electric Field on Charging Measurements on Individual Micron-size Dust Grains by Secondary Electron Emissions (United States)

    Tankosic, D.; Abbas, M. M.


    The dust charging by electron impact is an important dust charging process in Astrophysical, Planetary, and the Lunar environments. Low energy electrons are reflected or stick to the grains charging the dust grains negatively. At sufficiently high energies electrons penetrate the grain leading to excitation and emission of electrons referred to as secondary electron emission (SEE). Available theoretical models for the calculation of SEE yield applicable for neutral, planar or bulk surfaces are generally based on Sternglass Equation. However, viable models for charging of individual dust grains do not exist at the present time. Therefore, the SEE yields have to be obtained by some experimental methods at the present time. We have conducted experimental studies on charging of individual micron size dust grains in simulated space environments using an electrodynamic balance (EDB) facility at NASA-MSFC. The results of our extensive laboratory study of charging of individual micron-size dust grains by low energy electron impact indicate that the SEE by electron impact is a very complex process expected to be substantially different from the bulk materials. It was found that the incident electrons may lead to positive or negative charging of dust grains depending upon the grain size, surface potential, electron energy, electron flux, grain composition, and configuration. In this paper we give a more elaborate discussion about the possible effects of the AC field in the EDB on dust charging measurements by comparing the secondary electron emission time-period (tau (sub em) (s/e)) with the time-period (tau (sub ac) (ms)) of the AC field cycle in the EDB that we have briefly addressed in our previous publication.

  15. Generation of electron vortex beams using line charges via the electrostatic Aharonov-Bohm effect. (United States)

    Pozzi, Giulio; Lu, Peng-Han; Tavabi, Amir H; Duchamp, Martial; Dunin-Borkowski, Rafal E


    It has recently been shown that an electron vortex beam can be generated by the magnetic field surrounding the tip of a dipole-like magnet. This approach can be described using the magnetic Aharonov-Bohm effect and is associated with the fact that the end of a long magnetic rod can be treated approximately as a magnetic monopole. However, it is difficult to vary the magnetisation of the rod in such a setup and the electron beam vorticity is fixed for a given tip shape. Here, we show how a similar behaviour, which has the advantage of easy tuneability, can be achieved by making use of the electrostatic Aharonov-Bohm effect associated with an electrostatic dipole line. We highlight the analogies between the magnetic and electrostatic cases and use simulations of in-focus, Fresnel and Fraunhofer images to show that a device based on two parallel, oppositely charged lines that each have a constant charge density can be used to generate a tuneable electron vortex beam. We assess the effect of using a dipole line that has a finite length and show that if the charge densities on the two lines are different then an additional biprism-like effect is superimposed on the electron-optical phase. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  16. Copper vanadate nanowires-based MIS capacitors: Synthesis, characterization, and their electrical charge storage applications

    KAUST Repository

    Shahid, Muhammad


    Copper vanadate (CVO) nanowires were grown on Si/SiO2 substrates by thermal annealing technique. A thin film of a CVO precursor at 550 C under an ambient atmosphere could also be prepared. The electrical properties of the nanowires embedded in the dielectrical layer were examined by capacitance-voltage (C-V) measurements. The C-V curves for Au/CVO nanowires embedded in an hafnium oxide layer/SiO2/p-Si capacitor at 298 K showed a clockwise hysteresis loop when the gate bias was swept cyclically. The hysteresis characteristics were studied further at different frequencies, which clearly indicated that the traps in the nanowires have a large charging-discharging time and thus the as-synthesized nanowires can be utilized for electrical charge storage devices. © 2013 Springer Science+Business Media Dordrecht.

  17. Effect of CdS nanocrystals on charge transport mechanism in poly(3-hexylthiophene) (United States)

    Khan, Mohd Taukeer; Almohammedi, Abdullah


    The present manuscript demonstrates the optical and electrical characteristics of poly(3-hexylthiophene) (P3HT) and cadmium sulphide (CdS) hybrid nanocomposites. Optical results suggest that there is a formation of charge transfer complex (CTC) between host P3HT and guest CdS nanocrystals (NCs). Electrical properties of P3HT and P3HT-CdS thin films have been studied in hole only device configurations at different temperatures (290 K-150 K), and results were analysed by the space charge limited conduction mechanism. Density of traps and characteristic trap energy increase on incorporation of inorganic NCs in the polymer matrix, which might be due to the additional favourable energy states created by CdS NCs in the band gap of P3HT. These additional trap states assist charge carriers to move quicker which results in enhancement of hole mobility from 7 × 10-6 to 5.5 × 10-5 cm2/V s in nanocomposites. These results suggest that the P3HT-CdS hybrid system has desirable optical and electrical properties for its applications to photovoltaics devices.

  18. Enhanced memory effect with embedded graphene nanoplatelets in ZnO charge trapping layer

    Energy Technology Data Exchange (ETDEWEB)

    El-Atab, Nazek; Nayfeh, Ammar [Department of Electrical Engineering and Computer Science (EECS), Institute Center for Microsystems–iMicro, Masdar Institute of Science and Technology, Abu Dhabi (United Arab Emirates); Cimen, Furkan [Department of Electrical and Electronics Engineering, Bilkent University, Ankara 06800 (Turkey); Alkis, Sabri [UNAM-National Nanotechnology Research Center, Bilkent University, Ankara 06800 (Turkey); Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800 (Turkey); Okyay, Ali K. [Department of Electrical and Electronics Engineering, Bilkent University, Ankara 06800 (Turkey); UNAM-National Nanotechnology Research Center, Bilkent University, Ankara 06800 (Turkey); Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800 (Turkey)


    A charge trapping memory with graphene nanoplatelets embedded in atomic layer deposited ZnO (GNIZ) is demonstrated. The memory shows a large threshold voltage V{sub t} shift (4 V) at low operating voltage (6/−6 V), good retention (>10 yr), and good endurance characteristic (>10{sup 4} cycles). This memory performance is compared to control devices with graphene nanoplatelets (or ZnO) and a thicker tunnel oxide. These structures showed a reduced V{sub t} shift and retention characteristic. The GNIZ structure allows for scaling down the tunnel oxide thickness along with improving the memory window and retention of data. The larger V{sub t} shift indicates that the ZnO adds available trap states and enhances the emission and retention of charges. The charge emission mechanism in the memory structures with graphene nanoplatelets at an electric field E ≥ 5.57 MV/cm is found to be based on Fowler-Nordheim tunneling. The fabrication of this memory device is compatible with current semiconductor processing, therefore, has great potential in low-cost nano-memory applications.

  19. Effective Nanoparticle-based Gene Delivery by a Protease Triggered Charge Switch

    DEFF Research Database (Denmark)

    Gjetting, Torben; Jølck, Rasmus Irming; Andresen, Thomas Lars


    (ethylene glycol) (PEG) chain is investigated. Utilizing ethanol-mediated nucleic acid encapsulation to prepare lipo-nanoparticles (LNPs), LNPs that are stable in serum are obtained. The LNPs constitute a highly effective gene delivery systems in vitro and possess the right features for further...... in the cleaved peptide moiety. The cationic lipid DOTAP is used mainly to complex DNA and proton titratable DODAP is used to increase endosomal escape and enhance transfection efficiency. The idea of using a mixture of permanently charged and titratable cationic lipids shielded by a protease sensitive negatively...... charged lipo-peptide-PEG coat appears to be a highly efficient solution for achieving effective non-viral gene delivery and the results warrant further investigations....

  20. Polaron effects and electric field dependence of the charge carrier mobility in conjugated polymers. (United States)

    Jakobsson, Mattias; Stafström, Sven


    Charge transport in conjugated polymers has been investigated using Monte Carlo simulations implemented on top of the Marcus theory for donor-acceptor transition rates. In particular, polaron effects and the dependency of the mobility on the temperature and the applied electric field have been studied. The conclusions are that while the qualitative temperature dependence is similar to that predicted by Miller-Abrahams theory in the Gaussian disorder model (GDM), the electric field dependence is characterized by a crossover into the Marcus inverted region, not present in the GDM. Furthermore, available analytical approximations to describe the electric field dependence of the mobility in Marcus theory fail to fit the simulation data and hence cannot be used to directly draw conclusions about the importance of polaron effects for charge transport in conjugated polymers. © 2011 American Institute of Physics

  1. Combined effect of salt concentration and pressure gradients across charged membranes

    DEFF Research Database (Denmark)

    Benavente, Juana; Jonsson, Gunnar Eigil


    The combined effect of both concentration and pressure differences on electrical potential (Deltaphi) for two ion-exchanger membranes, one positively charged (AE) and another negatively charged (CE), measured with the membranes in contact with NaCl solutions was studied. Results show a linear...... to correlate the behaviour of the BP membrane with that corresponding to each sublayer, the same kind of measurements was carried out for both opposite external conditions, this means, applying the pressure on the cation exchanger (CABM) or on the anion exchanger membrane (ACBM), respectively. From values...... obtained at DeltaP = 0, the counter-ion transport number in each ion-exchange membrane was obtained and the contribution of membrane potential on Deltaphi values can be evaluated. Results show clear differences on both the membrane potential and the effect of pressure in the bipolar membrane depending...

  2. Synthesis of Stable Interfaces on SnO2 Surfaces for Charge-Transfer Applications (United States)

    Benson, Michelle C.

    The commercial market for solar harvesting devices as an alternative energy source requires them to be both low-cost and efficient to replace or reduce the dependence on fossil fuel burning. Over the last few decades there has been promising efforts towards improving solar devices by using abundant and non-toxic metal oxide nanomaterials. One particular metal oxide of interest has been SnO2 due to its high electron mobility, wide-band gap, and aqueous stability. However SnO2 based solar cells have yet to reach efficiency values of other metal oxides, like TiO2. The advancement of SnO2 based devices is dependent on many factors, including improved methods of surface functionalization that can yield stable interfaces. This work explores the use of a versatile functionalization method through the use of the Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. The CuAAC reaction is capable of producing electrochemically, photochemically, and electrocatalytically active surfaces on a variety of SnO2 materials. The resulting charge-transfer characteristics were investigated as well as an emphasis on understanding the stability of the resulting molecular linkage. We determined the CuAAC reaction is able to proceed through both azide-modified and alkyne-modified surfaces. The resulting charge-transfer properties showed that the molecular tether was capable of supporting charge separation at the interface. We also investigated the enhancement of electron injection upon the introduction of an ultra-thin ZrO2 coating on SnO2. Several complexes were used to fully understand the charge-transfer capabilities, including model systems of ferrocene and a ruthenium coordination complex, a ruthenium mononuclear water oxidation catalyst, and a commercial ruthenium based dye.

  3. High Performance Charge Breeder for HIE-ISOLDE and TSR@ISOLDE Applications

    CERN Document Server

    Shornikov, Andrey; Mertzig, Robert C.; Pikin, Alexander; Wenander, Fredrik J.C.


    We report on the development of the HEC2 (High Energy Compression and Current) charge breeder, a possible high performance successor to REXEBIS at ISOLDE. The new breeder would match the performance of the HIE-ISOLDE linac upgrade and make full use of the possible installation of a storage ring at ISOLDE (the TSR@ISOLDE initiative [1]). Dictated by ion beam acceptance and capacity requirements, the breeder features a 2-3.5 A electron beam. In many cases very high charge states, including bare ions up to Z=70 and Li/Na-like up to Z=92 could be requested for experiments in the storage ring, therefore, electron beam energies up to 150 keV are required. The electron-beam current density needed for producing ions with such high charge states at an injection rate into TSR of 0.5-1 Hz is between 10 and 20 kA/cm2, which agrees with the current density needed to produce A/q<4.5 ions for the HIE-ISOLDE linac with a maximum repetition rate of 100 Hz. The first operation of a prototype electron gun with a pulsed elect...

  4. Charge inversion via concurrent cation and anion transfer: application to corticosteroids. (United States)

    Hassell, Kerry M; LeBlanc, Yves; McLuckey, Scott A


    A novel charge inversion process that involves the removal of an excess cation from an analyte ion and the transfer of an anion to the neutral analyte in a single ion/ion encounter is described. Polyamidoamine (PAMAM) half-generation dendrimer anions that contain small anions, such as the chloride ion, were used as charge inversion reagents. Several competing processes can occur that include removal of the cation to neutralize the analyte, the removal of the excess cation and an additional proton to yield the deprotonated molecule, or removal of the excess cation and transfer of a small anion to the analyte. For the latter process to dominate, several requirements for both the reagent anion and the analyte cation must be met. The reagent anion must form multiply charged anions and must be able to incorporate one or more small anions for transfer. The analyte must have no strongly acidic sites as well as a relatively high affinity for small anion attachment. The PAMAM dendrimer anions must meet the conditions for the reagent anions and the cations of the corticosteroids meet the conditions for the analyte. The estrogenic steroid estrone, on the other hand, does not meet the requirements and, as a result, is largely neutralized when reacted with the reagent anions. This reaction, therefore, is highly selective and might serve as a useful reaction for the screening of appropriate analytes. Copyright © 2011 John Wiley & Sons, Ltd.

  5. Charge Transfer Dissociation (CTD) Mass Spectrometry of Peptide Cations: Study of Charge State Effects and Side-Chain Losses (United States)

    Li, Pengfei; Jackson, Glen P.


    1+, 2+, and 3+ precursors of substance P and bradykinin were subjected to helium cation irradiation in a 3D ion trap mass spectrometer. Charge exchange with the helium cations produces a variety of fragment ions, the number and type of which are dependent on the charge state of the precursor ions. For 1+ peptide precursors, fragmentation is generally restricted to C-CO backbone bonds ( a and x ions), whereas for 2+ and 3+ peptide precursors, all three backbone bonds (C-CO, C-N, and N-Cα) are cleaved. The type of backbone bond cleavage is indicative of possible dissociation channels involved in CTD process, including high-energy, kinetic-based, and ETD-like pathways. In addition to backbone cleavages, amino acid side-chain cleavages are observed in CTD, which are consistent with other high-energy and radical-mediated techniques. The unique dissociation pattern and supplementary information available from side-chain cleavages make CTD a potentially useful activation method for the structural study of gas-phase biomolecules.

  6. Longitudinal Space Charge Effects in the JLAB IR FEL SRF Linac

    CERN Document Server

    Hernandez-Garcia, Carlos; Behre, Chris; Benson, S V; Herman-Biallas, George; Boyce, James; Douglas, David; Dylla, Fred; Evans, Richard; Grippo, A; Gubeli, Joe; Hardy, David; Jordan, Kevin; Merminga, Lia; Neil, George; Preble, Joe; Shinn, Michelle D; Siggins, Tim; Walker, Richard; Williams, Gwyn; Yunn, Byung; Zhang, Shukui


    Observations of energy spread asymmetry when operating the Linac on either side of crest and longitudinal emittance growth have been confirmed by extending PARMELA simulations from the injector to the end of the first SRF Linac module. The asymmetry can be explained by the interaction of the accelerating electric field with that from longitudinal space charge effects within the electron bunch. This can be a major limitation to performance in FEL accelerators.

  7. Effect of collisions on dust particle charging via particle-in-cell Monte-Carlo collision (United States)

    Rovagnati, B.; Davoudabadi, M.; Lapenta, G.; Mashayek, F.


    In this paper, the effect of collisions on the charging and shielding of a single dust particle immersed in an infinite plasma is studied. A Monte-Carlo collision (MCC) algorithm is implemented in the particle-in-cell DEMOCRITUS code to account for the collisional phenomena which are typical of dusty plasmas in plasma processing, namely, electron-neutral elastic scattering, ion-neutral elastic scattering, and ion-neutral charge exchange. Both small and large dust particle radii, as compared to the characteristic Debye lengths, are considered. The trends of the steady-state dust particle potential at increasing collisionality are presented and discussed. The ions and electron energy distributions at various locations and at increasing collisionality in the case of large particle radius are shown and compared to their local Maxwellians. The ion-neutral charge-exchange collision is found to be by far the most important collisional phenomenon. For small particle radius, collisional effects are found to be important also at low level of collisionality, as more ions are collected by the dust particle due to the destruction of trapped ion orbits. For large particle radius, the major collisional effect is observed to take place in proximity of the presheath. Finally, the species energy distribution functions are found to approach their local Maxwellians at increasing collisionality.

  8. Hydrogen storage by adsorption on activated carbon: Investigation of the thermal effects during the charging process

    Energy Technology Data Exchange (ETDEWEB)

    Hermosilla-Lara, G. [Laboratoire d' Ingenierie des Materiaux et des Hautes Pressions, CNRS UPR 1311-Universite Paris 13, 93430 Villetaneuse (France); Laboratoire des Ecoulements Geophysiques et Industriels, BP 53, 38041 Grenoble Cedex 9 (France); Momen, G.; Le Neindre, B.; Hassouni, K. [Laboratoire d' Ingenierie des Materiaux et des Hautes Pressions, CNRS UPR 1311-Universite Paris 13, 93430 Villetaneuse (France); Marty, P.H. [Laboratoire des Ecoulements Geophysiques et Industriels, BP 53, 38041 Grenoble Cedex 9 (France)


    This paper presents an investigation of the thermal effects during high-pressure charging of a packed bed hydrogen storage tank. The studied column is packed with activated IRH3 carbon, which has an average surface area of 2600m{sup 2}g{sup -1} and is fed with hydrogen or helium from an external high-pressure source. The temperature at six locations in the storage tank and the pressure value at the bottom of the tank are recorded during the charging stage. Several experiments were carried out to investigate the effect of the initial flow rate on the temperature field in the reservoir and on the duration of the charging process. A study of the respective contribution of adsorption and mechanical dissipation effects to the thermal phenomena is done in the case of hydrogen. Experimental results are compared to those obtained with the commercial code Fluent. A fair agreement is found when comparing typical pressure and temperature evolutions during the tank filling. (author)

  9. Immobilization of bilirubin oxidase on graphene oxide flakes with different negative charge density for oxygen reduction. The effect of GO charge density on enzyme coverage, electron transfer rate and current density. (United States)

    Filip, Jaroslav; Andicsová-Eckstein, Anita; Vikartovská, Alica; Tkac, Jan


    Previously we showed that an effective bilirubin oxidase (BOD)-based biocathode using graphene oxide (GO) could be prepared in 2 steps: 1. electrostatic adsorption of BOD on GO; 2. electrochemical reduction of the BOD-GO composite to form a BOD-ErGO (electrochemically reduced GO) film on the electrode. In order to identify an optimal charge density of GO for BOD-ErGO composite preparation, several GO fractions differing in an average flake size and ζ-potential were prepared using centrifugation and consequently employed for BOD-ErGO biocathode preparation. A simple way to express surface charge density of these particular GO nanosheets was developed. The values obtained were then correlated with biocatalytic and electrochemical parameters of the prepared biocathodes, i.e. electrocatalytically active BOD surface coverage (Γ), heterogeneous electron transfer rate (kS) and a maximum biocatalytic current density. The highest bioelectrocatalytic current density of (597±25)μAcm(-2) and the highest Γ of (23.6±0.9)pmolcm(-2) were obtained on BOD-GO composite having the same moderate negative charge density, but the highest kS of (79.4±4.6)s(-1) was observed on BOD-GO composite having different negative charge density. This study is a solid foundation for others to consider the influence of a charge density of GO on direct bioelectrochemistry/bioelectrocatalysis of other redox enzymes applicable for construction of biosensors, bioanodes, biocathodes or biofuel cells. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Applications of an Automated and Quantitative CE-Based Size and Charge Western Blot for Therapeutic Proteins and Vaccines. (United States)

    Rustandi, Richard R; Hamm, Melissa; Lancaster, Catherine; Loughney, John W


    Capillary Electrophoresis (CE) is a versatile and indispensable analytical tool that can be applied to characterize proteins. In recent years, labor-intensive SDS-PAGE and IEF slab gels have been replaced with CE-SDS (CGE) and CE-IEF methods, respectively, in the biopharmaceutical industry. These two CE-based methods are now an industry standard and are an expectation of the regulatory agencies for biologics characterization. Another important and traditional slab gel technique is the western blot, which detects proteins using immuno-specific reagents after SDS-PAGE separation. This technique is widely used across industrial and academic laboratories, but it is very laborious, manual, time-consuming, and only semi-quantitative. Here, we describe the applications of a relatively new CE-based western blot technology which is automated, fast, and quantitative. We have used this technology for both charge- and size-based CE westerns to analyze biotherapeutic and vaccine products. The size-based capillary western can be used for fast antibody screening, clone selection, product titer, identity, and degradation while the charge-based capillary western can be used to study product charge heterogeneity. Examples using this technology for monoclonal antibody (mAb), Enbrel, CRM197, and Clostridium difficile (C. difficile) vaccine proteins are presented here to demonstrate the utility of the capillary western techniques. Details of sample preparation and experimental conditions for each capillary western mode are described in this chapter.

  11. Electrical Study of Trapped Charges in Copper-Doped Zinc Oxide Films by Scanning Probe Microscopy for Nonvolatile Memory Applications.

    Directory of Open Access Journals (Sweden)

    Ting Su

    Full Text Available Charge trapping properties of electrons and holes in copper-doped zinc oxide (ZnO:Cu films have been studied by scanning probe microscopy. We investigated the surface potential dependence on the voltage and duration applied to the copper-doped ZnO films by Kelvin probe force microscopy. It is found that the Fermi Level of the 8 at.% Cu-doped ZnO films shifted by 0.53 eV comparing to undoped ZnO films. This shift indicates significant change in the electronic structure and energy balance in Cu-doped ZnO films. The Fermi Level (work function of zinc oxide films can be tuned by Cu doping, which are important for developing this functional material. In addition, Kelvin probe force microscopy measurements demonstrate that the nature of contact at Pt-coated tip/ZnO:Cu interface is changed from Schottky contact to Ohmic contact by increasing sufficient amount of Cu ions. The charge trapping property of the ZnO films enhance greatly by Cu doping (~10 at.%. The improved stable bipolar charge trapping properties indicate that copper-doped ZnO films are promising for nonvolatile memory applications.

  12. Ultrafast broadband laser spectroscopy reveals energy and charge transfer in novel donor-acceptor triads for photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Roland, T; Ramirez, G Hernandez; Leonard, J; Mery, S; Haacke, S, E-mail: [Institut de Physique et Chimie des Materiaux de Strasbourg, Strasbourg University - CNRS UMR 7504, F-67034 Strasbourg (France)


    Triggered by the quest for new organic materials and micro-structures for photovoltaic applications, a novel class of donor-acceptor-donor (DAD) triads extended with siloxane chains has been synthesized in our labs. Because of the siloxane chains, the molecules self-organize into a smectic liquid crystal phase, resulting in a stacking of the DAD cores.We report here a preliminary study of the ultrafast dynamics of energy and charge transfer studied by femtosecond broadband transient absorption experiments on isolated triads in chloroform.

  13. Effects of Cylindrical Charge Geometry and Secondary Combustion Reactions on the Internal Blast Loading of Reinforced Concrete Structures

    Energy Technology Data Exchange (ETDEWEB)

    Price, Matthew A. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States)


    An understanding of the detonation phenomenon and airblast behavior for cylindrical high-explosive charges is essential in developing predictive capabilities for tests and scenarios involving these charge geometries. Internal tests on reinforced concrete structures allowed for the analysis of cylindrical charges and the effect of secondary reactions occurring in confined structures. The pressure profiles that occur close to a cylindrical explosive charge are strongly dependent on the length-to-diameter ratio (L/D) of the charge. This study presents a comparison of finite-element code models (i.e., AUTODYN) to empirical methods for predicting airblast behavior from cylindrical charges. Current finite element analysis (FEA) and blast prediction codes fail to account for the effects of secondary reactions (fireballs) that occur with underoxidized explosives. Theoretical models were developed for TNT and validated against literature. These models were then applied to PBX 9501 for predictions of the spherical fireball diameter and time duration. The following relationships for PBX 9501 were derived from this analysis (units of ft, lb, s). Comparison of centrally located equivalent weight charges using cylindrical and spherical geometries showed that the average impulse on the interior of the structure is ~3%–5% higher for the spherical charge. Circular regions of high impulse that occur along the axial direction of the cylindrical charge must be considered when analyzing structural response.

  14. Cooperative Charging Effects of Fibers From Electrospinning of Electrically Dissimilar Polymers

    National Research Council Canada - National Science Library

    Schreuder-Gibson, H. L; Gibson, P; Tsai, P; Gupta, P; Wilkes, G


    Electrical charging and residual charge decay of electrospun nonwoven webs comprised of two electrically dissimilar polymers were studied in an effort to investigate their filtration properties. Polystyrene (PS...

  15. Effect of caffeine on intramembrane charge movement and calcium transients in cut skeletal muscle fibres of the frog. (United States)

    Kovács, L; Szücs, G


    1. The authors have studied the effect of caffeine in subthreshold concentration (0.5 mmol l(-1) at 2-4 degrees C) on the contraction threshold, on intramembrane charge movement and calcium transients in voltage-clamped frog skeletal muscle fibres.2. The single-gap technique (Kovács & Schneider, 1978) was used for the voltage clamping of terminated segments of cut fibres. Ionic conductances were minimized by using caesium glutamate at the open end pool and tetraethylammonium sulphate and tetrodotoxin at the closed end pool.3. Myoplasmic calcium transients evoked by depolarizing pulses were recorded by measuring the changes in absorbance of the fibres at 720 nm after the intracellular application of Antipyrylazo III dye.4. The strength-duration curve for contraction threshold was shifted towards more negative membrane potentials in the presence of caffeine. Shift was more definite at shorter pulse durations than at the rheobase.5. The total amount of charge moving during the depolarizing pulses at different membrane potentials was not changed by caffeine treatment, whereas the threshold amounts of charge moved during the critical periods of the contraction threshold decreased at different voltages (by about 23%).6. In the presence of caffeine, calcium transients accompanying long (100 ms) depolarizing pulses showed increased voltage-dependent peak amplitudes, rising phases and rate coefficients referring to calcium release, but a decreased voltage-dependent re-uptake rate either during or after the pulse.7. Calcium transients evoked by depolarizing pulses along the strength-duration curve for contraction threshold gave the same peak amplitudes (ranging from 0.9 to 2.8 mumol l(-1) free myoplasmic calcium on different fibres), but membrane-potential-dependent latency times and rising phases. The rate coefficients for declining phase did not depend on the preceding pulse voltage.8. On applying caffeine, the calcium transients related to the contraction threshold also

  16. Dynamics of charge carrier trapping in NO2 sensors based on ZnO field-effect transistors

    NARCIS (Netherlands)

    Andringa, Anne-Marije; Vlietstra, Nynke; Smits, Edsger C. P.; Spijkman, Mark-Jan; Gomes, Henrique L.; Klootwijk, Johan H.; Blom, Paul W. M.; de Leeuw, Dago M.


    Nitrogen dioxide (NO2) detection with ZnO field-effect transistors is based on charge carrier trapping. Here we investigate the dynamics of charge trapping and recovery as a function of temperature by monitoring the threshold voltage shift. The threshold voltage shifts follow a stretched-exponential

  17. High performance charge breeder for HIE-ISOLDE and TSR@ISOLDE applications

    Energy Technology Data Exchange (ETDEWEB)

    Shornikov, Andrey, E-mail:; Mertzig, Robert C.; Wenander, Fredrik J. C. [CERN, Geneva 23, CH-1211 (Switzerland); Beebe, Edward N.; Pikin, Alexander [Brookhaven National Lab, Upton, NY 11973 (United States)


    We report on the development of the HEC{sup 2} (High Energy Compression and Current) charge breeder, a possible high performance successor to REXEBIS at ISOLDE. The new breeder would match the performance of the HIE-ISOLDE linac upgrade and make full use of the possible installation of a storage ring at ISOLDE (the TSR@ISOLDE initiative [1]). Dictated by ion beam acceptance and capacity requirements, the breeder features a 2–3.5 A electron beam. In many cases very high charge states, including bare ions up to Z=70 and Li/Na-like up to Z=92 could be requested for experiments in the storage ring, therefore, electron beam energies up to 150 keV are required. The electron-beam current density needed for producing ions with such high charge states at an injection rate into TSR of 0.5–1 Hz is between 10 and 20 kA/cm{sup 2}, which agrees with the current density needed to produce A/q<4.5 ions for the HIE-ISOLDE linac with a maximum repetition rate of 100 Hz. The first operation of a prototype electron gun with a pulsed electron beam of 1.5 A and 30 keV was demonstrated in a joint experiment with BNL [2]. In addition, we report on further development aiming to achieve CW operation of an electron beam having a geometrical transverse ion-acceptance matching the injection of 1{sup +} ions (11.5 μm), and an emittance/energy spread of the extracted ion beam matching the downstream mass separator and RFQ (0.08 μm normalized / ± 1%)

  18. Effects of the Charge Ions Strength on the Swelling of Organic-Inorganic Nanogels

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Qin; Lu, Xiangguo; Wang, Jing; Guo, Qi; Niu, Liwei [Northeast Petroleum University, Daqing (China)


    The swelling behavior and swelling mechanism of hydrogels can be greatly affected by the charge strength of ions in them. To investigate such effects, we prepared two gels: a carboxylic acid gel (CAG) and a poly (2-acrylamide–methyl propane sulfonic acid) gel (SAG) based on starchy polyacrylamide (PAM) nanocomposite gels, both with montmorillonite, which underwent in situ intercalation, and used them as probes in swelling experiments. The equilibrium swelling rates (ESRs) of the hydrogels in both salt water and acidic water strongly depended on the charge strength of the ions in the chains. SAG had a higher ESR than CAG at the same mole ratio of polymer/water, which is attributed to the greater electrostatic repulsion between the strong electrolyte ions of SAG. Both water salinity and hydrogen ion contact of the hydrogels weakened ESR with the enhancement of charge ionic strength. The downward trend of ESR with increasing concentration of salt or hydrogen ions became weaker in SAG compared to CAG, which is attributed to the shielding and deprotonation effects of the strong electrolyte ions. Regarding the swelling mechanism, the chain relaxation occurred in neutral and acidic solutions for SAG and in neutral and weak acidic solutions for CAG, but water diffusion dominated in strong acidic solutions for CAG, leading to different swelling behaviors.

  19. The Effect of Surface Charges on the Cellular Uptake of Liposomes Investigated by Live Cell Imaging. (United States)

    Kang, Ji Hee; Jang, Woo Young; Ko, Young Tag


    Liposomes have been developed as versatile nanocarriers for various pharmacological agents. The effect of surface charges on the cellular uptake of the liposomes has been studied by various methods using mainly fixed cells with inevitable limitations. Live cell imaging has been proposed as an alternative methods to overcome the limitations of the fixed cell-based analysis. In this study, we aimed to investigate the effects of surface charges on cellular association and internalization of the liposomes using live cell imaging. We studied the cellular association and internalization of liposomes with different surface charge using laser scanning confocal microscopy (LSCM) equipped with live cell chamber system. Flow cytometry was also carried out using flow cytometer (FACS) for comparison. All of the cationic, neutral and anionic liposomes showed time-dependent cellular uptake through specific endocytic pathways. In glioblastoma U87MG cells, the cationic and anionic liposomes were mainly taken up via macropinocytosis, while the neutral liposomes mainly via caveolae-mediated endocytosis. In fibroblast NIH/3T3 cells, all of the three liposomes entered into the cell via clathrin-mediated endocytosis. This study provides a better understanding on the cellular uptake mechanisms of the liposomes, which could contribute significantly to development of liposome-based drug delivery systems.

  20. Structural and isospin effects on balance energy and transition energy via different nuclear charge radii parameterizations (United States)

    Sangeeta; Kaur, Varinderjit


    The structural and isospin effects have been studied through isospin dependent and independent nuclear charge radii parameterizations on the collective flow within the framework of Isospin-dependent Quantum Molecular Dynamics (IQMD) model. The calculations have been carried out by using two approaches: (i) for the reaction series having fixed N / Z ratio and (ii) for the isobaric reaction series with different N / Z ratio. Our results indicate that there is a considerable effect of radii parameterizations on the excitation function of reduced flow (∂v1/∂Yred) and elliptical flow (v2). Both balance energy (Ebal) and transition energy (Etrans) are enhanced with increase in radii of reacting nuclei and found to follow a power law with nuclear charge radii. The exponent τ values show that the elliptical flow is more sensitive towards different nuclear charge radii as compared to reduced flow. Moreover, we observe that our theoretical calculation of Ebal and Etrans are in agreement with the experimental data provided by GSI, INDRA and FOPI collaborations.

  1. Simulation of space-charge effects in an ungated GEM-based TPC

    Energy Technology Data Exchange (ETDEWEB)

    Böhmer, F.V., E-mail:; Ball, M.; Dørheim, S.; Höppner, C.; Ketzer, B.; Konorov, I.; Neubert, S.; Paul, S.; Rauch, J.; Vandenbroucke, M.


    A fundamental limit to the application of Time Projection Chambers (TPCs) in high-rate experiments is the accumulation of slowly drifting ions in the active gas volume, which compromises the homogeneity of the drift field and hence the detector resolution. Conventionally, this problem is overcome by the use of ion-gating structures. This method, however, introduces large dead times and restricts trigger rates to a few hundred per second. The ion gate can be eliminated from the setup by the use of Gas Electron Multiplier (GEM) foils for gas amplification, which intrinsically suppress the backflow of ions. This makes the continuous operation of a TPC at high rates feasible. In this work, Monte Carlo simulations of the buildup of ion space charge in a GEM-based TPC and the correction of the resulting drift distortions are discussed, based on realistic numbers for the ion backflow in a triple-GEM amplification stack. A TPC in the future P{sup ¯}ANDA experiment at FAIR serves as an example for the experimental environment. The simulations show that space charge densities up to 65 fC cm{sup −3} are reached, leading to electron drift distortions of up to 10 mm. The application of a laser calibration system to correct these distortions is investigated. Based on full simulations of the detector physics and response, we show that it is possible to correct for the drift distortions and to maintain the good momentum resolution of the GEM-TPC.

  2. Environment effect on spectral and charge distribution characteristics of some drugs of folate derivatives (United States)

    Khadem Sadigh, M.; Zakerhamidi, M. S.; Seyed Ahmadian, S. M.; Johari-Ahar, M.; Zare Haghighi, L.


    Molecular surrounding media as an important factor can effect on the operation of wide variety of drugs. For more study in this paper, spectral properties of Methotrexate and Folinic acid have been studied in various solvents. Our results show that the photo-physical of solute molecules depend strongly on solute-solvent interactions and active groups in their chemical structures. In order to investigate the contribution of specific and nonspecific interactions on the various properties of drug molecules, the linear solvation energy relationships concept is used. Moreover, charge distribution characteristics of used samples with various resonance structures in solvent environments were calculated by means of solvatochromic method. The high value of dipole moments in excited state show that local intramolecular charge transfer can occur by excitation. These results about molecular interactions can be extended to biological systems and can indicate completely the behaviors of Methotrexate and Folinic acid in polar solvents such as water in body system.

  3. Three-dimensional effects in resonant charge transfer between atomic particles and nanosystems (United States)

    Gainullin, I. K.; Sonkin, M. A.


    Resonant charge transfer (RCT) between negative ions and a metallic nanosystem was investigated by means of a high-performance ab initio three-dimensional (3D) numerical solver. During RCT, an electron was shown to occupy succesively nanosystem eigenstates along the z , ρ , and φ coordinates. Electron tunneling into a nanosystem is a reversible process, because after some time the electron propagates back to the ion. RCT efficiency in a nanosystem was found to exhibit quantum-size effects as well as lateral ion position dependence. This means that during ion-surface interaction, the nanosystem's size and the ion trajectory strongly influence the final charge state of the ion. In the case of real 3D systems (without cylindrical symmetry), the electron density currents form quantum vortices; this result is rather nontrivial for static systems. In addition, the limits of the adiabatic approximation (rate equation) for the RCT calculation with nanosystems are defined.

  4. Estimation of charge effects of ultrafine channel utilizing junctionless transistor with nanodot-type floating gate (United States)

    Ban, Takahiko; Migita, Shinji; Uenuma, Mutsunori; Okamoto, Naofumi; Ishikawa, Yasuaki; Uraoka, Yukiharu; Yamashita, Ichiro; Yamamoto, Shin-ichi


    Metal nanoparticles (NPs) embedded in junctionless field-effect transistors (JL-FETs) with a channel length of about sub-10-nm are fabricated and demonstrated. The anisotropic wet etching of a silicon-on-insulator (SOI) substrate was utilized to form V-grooves and define a nanometer-scale channel. Metal NPs are selectively placed onto the bottom of a V-groove using a bio nano process (BNP). A JL-FET is applied to a floating gate memory and used to study the impacts of charges close to the short channel. Low-voltage operation and memory behavior of broad threshold voltage appear. It is estimated by simulation that positive and negative charges equivalent to approximately 10 electrons are accumulated in one NP. It is expected that the JL-FETs can overcome the scaling limitations of floating gate memories.

  5. Binding of chloroquine to ionic micelles: Effect of pH and micellar surface charge

    Energy Technology Data Exchange (ETDEWEB)

    Souza Santos, Marcela de, E-mail: [Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, s/n, Ribeirão Preto, São Paulo 14040-903 (Brazil); Perpétua Freire de Morais Del Lama, Maria, E-mail: [Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, s/n, Ribeirão Preto, São Paulo 14040-903 (Brazil); Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Departamento de Química Analítica, Universidade Estadual de Campinas, Cidade Universitária Zeferino Vaz, s/n, Campinas, São Paulo 13083-970 (Brazil); Siuiti Ito, Amando, E-mail: [Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, São Paulo 14040-901 (Brazil); and others


    The pharmacological action of chloroquine relies on its ability to cross biological membranes in order to accumulate inside lysosomes. The present work aimed at understanding the basis for the interaction between different chloroquine species and ionic micelles of opposite charges, the latter used as a simple membrane model. The sensitivity of absorbance and fluorescence of chloroquine to changes in its local environment was used to probe its interaction with cetyltrimethylammonium micelles presenting bromide (CTAB) and sulfate (CTAS) as counterions, in addition to dodecyl sulfate micelles bearing sodium (SDS) and tetramethylammonium (TMADS) counterions. Counterion exchange was shown to have little effect on drug–micelle interaction. Chloroquine first dissociation constant (pKa{sub 1}) shifted to opposite directions when anionic and cationic micelles were compared. Chloroquine binding constants (K{sub b}) revealed that electrostatic forces mediate charged drug–micelle association, whereas hydrophobic interactions allowed neutral chloroquine to associate with anionic and cationic micelles. Fluorescence quenching studies indicated that monoprotonated chloroquine is inserted deeper into the micelle surface of anionic micelles than its neutral form, the latter being less exposed to the aqueous phase when associated with cationic over anionic assemblies. The findings provide further evidence that chloroquine–micelle interaction is driven by a tight interplay between the drug form and the micellar surface charge, which can have a major effect on the drug biological activity. -- Highlights: • Chloroquine (CQ) pKa{sub 1} increased for SDS micelles and decreased for CTAB micelles. • CQ is solubilized to the surface of both CTAB and SDS micelles. • Monoprotonated CQ is buried deeper into SDS micelles than neutral CQ. • Neutral CQ is less exposed to aqueous phase in CTAB over SDS micelles. • Local pH and micellar surface charge mediate interaction of CQ with

  6. Applications of gauge/gravity dualities with charged Anti-de Sitter black holes

    Energy Technology Data Exchange (ETDEWEB)

    Grass, Viviane Theresa


    In this thesis, we deal with different applications of the Anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence. The AdS/CFT correspondence, which is also more generally referred to as gauge/gravity duality, is a conjectured duality in superstring theory between strongly-coupled four-dimensional N=4 superconformal Yang-Mills theory and weakly-coupled type IIB string theory in five-dimensional AdS spacetime. This duality provides a powerful method to investigate strongly-coupled low-energy systems in four dimensions by substitutionally carrying out calculations in five-dimensional weakly-coupled supergravity. In this work, we use the AdS/CFT correspondence to explore three different strongly-coupled systems, namely a brane world accommodating a strongly-coupled field theory, a strongly-coupled fluid on a three-sphere and a strongly-coupled p-wave superfluid. In all these cases, the dual supergravity descriptions involve charged AdS black holes. The first system studied here is a Randall-Sundrum brane world moving in the background of a five-dimensional non-extremal black hole of N=2 gauged supergravity. The equations of motion of the brane are found to be equal to the Friedmann-Robertson-Walker (FRW) equations for a closed universe. The closed brane universe has special thermodynamic properties. The energy of the brane field theory exhibits a subextensive Casimir contribution, and the entropy can be expressed as a Cardy-Verlinde-type formula. We show that the equations for both quantities can take forms that strongly resemble the two FRW equations. At the horizon of the black hole, these two sets of equations are shown to even merge with each other which might suggest the existence of a common underlying theory. In addition, as a by-product result, the non-extremal black hole solutions considered here are found to admit an alternative description in terms of first-order flow equations similar to those which are well-known from the attractor mechanism of

  7. Effects of High Temperature and Thermal Cycling on the Performance of Perovskite Solar Cells: Acceleration of Charge Recombination and Deterioration of Charge Extraction. (United States)

    Sheikh, Arif D; Munir, Rahim; Haque, Md Azimul; Bera, Ashok; Hu, Weijin; Shaikh, Parvez; Amassian, Aram; Wu, Tom


    In this work, we investigated the effects of high operating temperature and thermal cycling on the photovoltaic (PV) performance of perovskite solar cells (PSCs) with a typical mesostructured (m)-TiO2-CH3NH3PbI3-xClx-spiro-OMeTAD architecture. After temperature-dependent grazing-incidence wide-angle X-ray scattering, in situ X-ray diffraction, and optical absorption experiments were carried out, the thermal durability of PSCs was tested by subjecting the devices to repetitive heating to 70 °C and cooling to room temperature (20 °C). An unexpected regenerative effect was observed after the first thermal cycle; the average power conversion efficiency (PCE) increased by approximately 10% in reference to the as-prepared device. This increase of PCE was attributed to the heating-induced improvement of the crystallinity and p doping in the hole transporter, spiro-OMeTAD, which promotes the efficient extraction of photogenerated carriers. However, further thermal cycles produced a detrimental effect on the PV performance of PSCs, with the short-circuit current and fill factor degrading faster than the open-circuit voltage. Similarly, the PV performance of PSCs degraded at high operation temperatures; both the short-circuit current and open-circuit voltage decreased with increasing temperature, but the temperature-dependent trend of the fill factor was the opposite. Our impedance spectroscopy analysis revealed a monotonous increase of the charge-transfer resistance and a concurrent decrease of the charge-recombination resistance with increasing temperature, indicating a high recombination of charge carriers. Our results revealed that both thermal cycling and high temperatures produce irreversible detrimental effects on the PSC performance because of the deteriorated interfacial photocarrier extraction. The present findings suggest that the development of robust charge transporters and proper interface engineering are critical for the deployment of perovskite PVs in harsh

  8. Effects of High Temperature and Thermal Cycling on the Performance of Perovskite Solar Cells: Acceleration of Charge Recombination and Deterioration of Charge Extraction

    KAUST Repository

    Sheikh, Arif D.


    In this work, we investigated the effects of high operating temperature and thermal cycling on the photovoltaic performance of perovskite solar cells (PSCs) with a typical mesostructured (m)-TiO2-CH3NH3PbI3-xClx-spiro-OMeTAD architecture. After carrying out temperature-dependent grazing incidence wide-angle X-ray scattering (GIWAXS), in-situ X-ray diffraction (XRD) and optical absorption experiments, thermal durability of PSCs was tested by subjecting the devices to repetitive heating to 70 °C and cooling to room temperature (20 °C). An unexpected regenerative effect was observed after the first thermal cycle; the average power conversion efficiency (PCE) increased by approximately 10 % in reference to the as-prepared device. This increase of PCE was attributed to the heating-induced improvement of crystallinity and p-doping in the hole-transporter, Spiro-OMeTAD, which promotes the efficient extraction of photo-generated carriers. However, further thermal cycles produced a detrimental effect on the photovoltaic performance of PSCs with short-circuit current and fill factor degrading faster than the open-circuit voltage. Similarly, the photovoltaic performance of PSCs degraded at high operation temperatures; both short-circuit current and open-circuit voltage decreased with increasing temperature, but the temperature-dependent trend of fill factor was opposite. Our impedance spectroscopy analysis revealed a monotonous increase of charge transfer resistance and a concurrent decrease of charge recombination resistance with increasing temperature, indicating high recombination of charge carriers. Our results revealed that both thermal cycling and high temperatures produce irreversible detrimental effects on the PSC performance due to the deteriorated interfacial photo-carrier extraction. The present findings suggest that development of robust charge transporters and proper interface engineering are critical for the deployment of perovskite photovoltaics in harsh

  9. Hydrodynamic modeling of NOM transport in UF: effects of charge density and ionic strength on effective size and sieving. (United States)

    Yuan, Yanxiao; Kilduff, James E


    The transport behavior of natural organic matter (NOM) across polyethersulfone (PES) UF membranes having a range of nominal molecularweight cutoffs (MWCOs) was investigated and described with a hydrodynamic transport model. Transport of whole NOM and NOM fractionated on an anion exchange resin (IRA 958) was measured to investigate the impact of NOM size and charge density. It was found that the dominant transport mechanism, characterized by the membrane Peclet number, depended on the membrane MWCO, and transitioned from diffusion to convection at a MWCO of about 10 kDa. Increasing ionic strength significantly decreased the effective solute radius and decreased the observed rejection of charged NOM fractions, whereas no significant change was seen for neutral fractions. Using an available theoretical model for partitioning of charged solutes, the effect of ionic strength on the electrical double layer thickness can account for the observed changes in effective solute radius. These results provide insight into the role of solute charge and electrostatic interactions in NOM transport behavior.

  10. Isolated effects of external bath osmolality, solute concentration, and electrical charge on solute transport across articular cartilage. (United States)

    Pouran, Behdad; Arbabi, Vahid; Zadpoor, Amir A; Weinans, Harrie


    The metabolic function of cartilage primarily depends on transport of solutes through diffusion mechanism. In the current study, we use contrast enhanced micro-computed tomography to determine equilibrium concentration of solutes through different cartilage zones and solute flux in the cartilage, using osteochondral plugs from equine femoral condyles. Diffusion experiments were performed with two solutes of different charge and approximately equal molecular weight, namely iodixanol (neutral) and ioxaglate (charge=-1) in order to isolate the effects of solute's charge on diffusion. Furthermore, solute concentrations as well as bath osmolality were changed to isolate the effects of steric hindrance on diffusion. Bath concentration and bath osmolality only had minor effects on the diffusion of the neutral solute through cartilage at the surface, middle and deep zones, indicating that the diffusion of the neutral solute was mainly Fickian. The negatively charged solute diffused considerably slower through cartilage than the neutral solute, indicating a large non-Fickian contribution in the diffusion of charged molecules. The numerical models determined maximum solute flux in the superficial zone up to a factor of 2.5 lower for the negatively charged solutes (charge=-1) as compared to the neutral solutes confirming the importance of charge-matrix interaction in diffusion of molecules across cartilage. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

  11. Space charge effect measurements for a multi-channel ionization chamber used for synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Nasr, Amgad


    In vivo coronary angiography is one of the techniques used to investigate the heart diseases, by using catheter to inject a contrast medium of a given absorption coefficient into the heart vessels. Taking X-ray images produced by X-ray tube or synchrotron radiation for visualizing the blood in the coronary arteries. As the synchrotron radiation generated by the relativistic charged particle at the bending magnets, which emits high intensity photons in comparison with the X-ray tube. The intensity of the synchrotron radiation is varies with time. However for medical imaging it's necessary to measure the incoming intensity with the integrated time. The thesis work includes building a Multi-channel ionization chamber which can be filled with noble gases N{sub 2}, Ar and Xe with controlled inner pressure up to 30 bar. This affects the better absorption efficiency in measuring the high intensity synchrotron beam fluctuation. The detector is a part of the experimental setup used in the k-edge digital subtraction angiography project, which will be used for correcting the angiography images taken by another detector at the same time. The Multi-channel ionization chamber calibration characteristics are measured using 2 kW X-ray tube with molybdenum anode with characteristic energy of 17.44 keV. According to the fast drift velocity of the electrons relative to the positive ions, the electrons will be collected faster at the anode and will induce current signals, while the positive ions is still drifting towards the cathode. However the accumulation of the slow ions inside the detector disturbs the homogeneous applied electric field and leads to what is known a space charge effect. In this work the space charge effect is measured with very high synchrotron photons intensity from EDR beam line at BESSYII. The strong attenuation in the measured amplitude signal occurs when operating the chamber in the recombination region. A plateau is observed at the amplitude signal when

  12. Space charge

    CERN Document Server

    Schindl, Karlheinz


    The Coulomb forces between the charged particles of a high-intensity beam in an accelerator create a self-field which acts on the particles inside the beam like a distributed lens, defocusing in both transverse planes. A beam moving with speed n is accompanied by a magnetic field which partially cancels the electrostatic defocusing effect, with complete cancellation at c, the speed of light. The effect of this 'direct space charge' is evaluated for transport lines and synchrotrons where the number of betatron oscillations per machine turn, Q, is reduced by DQ. In a real accelerator, the beam is also influenced by the environment (beam pipe, magnets, etc.) which generates 'indirect' space charge effects. For a smooth and perfectly conducting wall, they can easily be evaluated by introducing image charges and currents. These 'image effects' do not cancel when n approaches c, thus they become dominant for high-energy synchrotrons. Each particle in the beam has its particular incoherent tune Q and incoherent tune...

  13. Influence of electric current intensity on the performance of electroformed copper liner for shaped charge application

    Directory of Open Access Journals (Sweden)

    Tamer Elshenawy


    Full Text Available Electrolytic Copper used in the shaped charge liner manufacturing can be produced from acid solution using electro-deposition technique. The intensity of the applied electric current controls the quality of the produced copper grade. The electric current intensity within the electrolytic acidic solution cell with the minimum oxygen and sulfur elements in the produced copper was optimized and found to be 30–40 A/Ft2. The elemental composition of the obtained electrolytic copper was determined using high-end stationary vacuum spectrometer, while the oxygen was determined precisely using ELTRA ONH-2000 apparatus. Besides, SEM was used to investigate the shape of the copper texture inside the deposited layers and to determine the average grain size. New relations have been obtained between the applied current intensity and both the oxygen and sulfur contents and the average grain size of the produced copper. Experimental result showed that when the applied current density increases to a certain limit, the oxygen and sulfur content in the electrolytic copper decreases. Performance of the produced copper liner was investigated by the static firing of a small caliber shaped charge containing an electro-formed copper liners, where the penetration depth of the optimized electrolytic liner was enhanced by 22.7% compared to that of baseline non-optimized liner.

  14. Charge Transfer Mechanism in Titanium-Doped Microporous Silica for Photocatalytic Water-Splitting Applications

    Directory of Open Access Journals (Sweden)

    Wendi Sapp


    Full Text Available Solar energy conversion into chemical form is possible using artificial means. One example of a highly-efficient fuel is solar energy used to split water into oxygen and hydrogen. Efficient photocatalytic water-splitting remains an open challenge for researchers across the globe. Despite significant progress, several aspects of the reaction, including the charge transfer mechanism, are not fully clear. Density functional theory combined with density matrix equations of motion were used to identify and characterize the charge transfer mechanism involved in the dissociation of water. A simulated porous silica substrate, using periodic boundary conditions, with Ti4+ ions embedded on the inner pore wall was found to contain electron and hole trap states that could facilitate a chemical reaction. A trap state was located within the silica substrate that lengthened relaxation time, which may favor a chemical reaction. A chemical reaction would have to occur within the window of photoexcitation; therefore, the existence of a trapping state may encourage a chemical reaction. This provides evidence that the silica substrate plays an integral part in the electron/hole dynamics of the system, leading to the conclusion that both components (photoactive materials and support of heterogeneous catalytic systems are important in optimization of catalytic efficiency.

  15. Two-Dimensional Electronic Spectroscopies for Probing Electronic Structure and Charge Transfer: Applications to Photosystem II

    Energy Technology Data Exchange (ETDEWEB)

    Ogilvie, Jennifer P. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Physics


    Photosystem II (PSII) is the only known natural enzyme that uses solar energy to split water, making the elucidation of its design principles critical for our fundamental understanding of photosynthesis and for our ability to mimic PSII’s remarkable properties. This report discusses progress towards addressing key open questions about the PSII RC. It describes new spectroscopic methods that were developed to answer these questions, and summarizes the outcomes of applying these methods to study the PSII RC. Using 2D electronic spectroscopy and 2D electronic Stark spectroscopy, models for the PSII RC were tested and refined. Work is ongoing to use the collected data to elucidate the charge separation mechanism in the PSII RC. Coherent dynamics were also observed in the PSII RC for the first time. Through extensive characterization and modeling we have assigned these coherences as vibronic in nature, and believe that they reflect resonances between key vibrational pigment modes and electronic energy gaps that may facilitate charge separation. Work is ongoing to definitively test the functional relevance of electronic-vibrational resonances.

  16. Dispatch Control with PEV Charging and Renewables for Multiplayer Game Application

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Nathan; Johnson, Brian; McJunkin, Timothy; Scoffield, Don; White, Sera


    This paper presents a demand response model for a hypothetical microgrid that integrates renewable resources and plug-in electric vehicle (PEV) charging systems. It is assumed that the microgrid has black start capability and that external generation is available for purchase while grid connected to satisfy additional demand. The microgrid is developed such that in addition to renewable, non-dispatchable generation from solar, wind and run of the river hydroelectric resources, local dispatchable generation is available in the form of small hydroelectric and moderately sized gas and coal fired facilities. To accurately model demand, the load model is separated into independent residential, commercial, industrial, and PEV charging systems. These are dispatched and committed based on a mixed integer linear program developed to minimize the cost of generation and load shedding while satisfying constraints associated with line limits, conservation of energy, and ramp rates of the generation units. The model extends a research tool to longer time frames intended for policy setting and educational environments and provides a realistic and intuitive understanding of beneficial and challenging aspects of electrification of vehicles combined with integration of green electricity production.

  17. Analysis and development of fourth order LCLC resonant based capacitor charging power supply for pulse power applications. (United States)

    Naresh, P; Hitesh, C; Patel, A; Kolge, T; Sharma, Archana; Mittal, K C


    A fourth order (LCLC) resonant converter based capacitor charging power supply (CCPS) is designed and developed for pulse power applications. Resonant converters are preferred t utilize soft switching techniques such as zero current switching (ZCS) and zero voltage switching (ZVS). An attempt has been made to overcome the disadvantages in 2nd and 3rd resonant converter topologies; hence a fourth order resonant topology is used in this paper for CCPS application. In this paper a novel fourth order LCLC based resonant converter has been explored and mathematical analysis carried out to calculate load independent constant current. This topology provides load independent constant current at switching frequency (fs) equal to resonant frequency (fr). By changing switching condition (on time and dead time) this topology has both soft switching techniques such as ZCS and ZVS for better switching action to improve the converter efficiency. This novel technique has special features such as low peak current through switches, DC blocking for transformer, utilizing transformer leakage inductance as resonant component. A prototype has been developed and tested successfully to charge a 100 μF capacitor to 200 V.

  18. Application of Gauss's law space-charge limited emission model in iterative particle tracking method

    Energy Technology Data Exchange (ETDEWEB)

    Altsybeyev, V.V., E-mail:; Ponomarev, V.A.


    The particle tracking method with a so-called gun iteration for modeling the space charge is discussed in the following paper. We suggest to apply the emission model based on the Gauss's law for the calculation of the space charge limited current density distribution using considered method. Based on the presented emission model we have developed a numerical algorithm for this calculations. This approach allows us to perform accurate and low time consumpting numerical simulations for different vacuum sources with the curved emitting surfaces and also in the presence of additional physical effects such as bipolar flows and backscattered electrons. The results of the simulations of the cylindrical diode and diode with elliptical emitter with the use of axysimmetric coordinates are presented. The high efficiency and accuracy of the suggested approach are confirmed by the obtained results and comparisons with the analytical solutions.

  19. The effect of the abolition of user charges on the demand for ambulatory doctor visits


    Žílová, Pavlína; Votápková, Jana


    The paper estimates the effect of the abolition of user charges for outpatient care (30 CZK/1.2 EUR) in 2009 on the demand for ambulatory doctor visits in the Czech Republic. The r eform a pplied only to children, which enabled us to take the difference-in-differences approach. Children constitute a treatment group, whereas adults serve as a control group. Besides the treatment effect, we control also for a number of personal characteristics using a micro-level data (EU-SILC). We estimate two...

  20. Polarization and charge-transfer effects in aqueous solution via ab initio QM/MM simulations. (United States)

    Mo, Yirong; Gao, Jiali


    Combined ab initio quantum mechanical and molecular mechanical (QM/MM) simulations coupled with the block-localized wave function energy decomposition (BLW-ED) method have been conducted to study the solvation of two prototypical ionic systems, acetate and methylammonium ions in aqueous solution. Calculations reveal that the electronic polarization between the targeted solutes and water is the primary many-body effect, whereas the charge-transfer term only makes a small fraction of the total solute-solvent interaction energy. In particular, the polarization effect is dominated by the solvent (water) polarization.

  1. Effect of the charged-lepton's mass on the quasielastic neutrino cross sections (United States)

    Ankowski, Artur M.


    Martini et al. [Phys. Rev. C 94, 015501 (2016), 10.1103/PhysRevC.94.015501] recently observed that when the produced-lepton's mass plays an important role, the charged-current quasielastic cross section for muon neutrinos can be higher than that for electron neutrinos. Here I argue that this effect appears solely in the theoretical descriptions of nuclear effects in which nucleon knockout requires the energy and momentum transfers to lie in a narrow range of the kinematically allowed values.

  2. Axisymmetric charge-conservative electromagnetic particle simulation algorithm on unstructured grids: Application to microwave vacuum electronic devices (United States)

    Na, Dong-Yeop; Omelchenko, Yuri A.; Moon, Haksu; Borges, Ben-Hur V.; Teixeira, Fernando L.


    We present a charge-conservative electromagnetic particle-in-cell (EM-PIC) algorithm optimized for the analysis of vacuum electronic devices (VEDs) with cylindrical symmetry (axisymmetry). We exploit the axisymmetry present in the device geometry, fields, and sources to reduce the dimensionality of the problem from 3D to 2D. Further, we employ 'transformation optics' principles to map the original problem in polar coordinates with metric tensor diag (1 ,ρ2 , 1) to an equivalent problem on a Cartesian metric tensor diag (1 , 1 , 1) with an effective (artificial) inhomogeneous medium introduced. The resulting problem in the meridian (ρz) plane is discretized using an unstructured 2D mesh considering TEϕ-polarized fields. Electromagnetic field and source (node-based charges and edge-based currents) variables are expressed as differential forms of various degrees, and discretized using Whitney forms. Using leapfrog time integration, we obtain a mixed E - B finite-element time-domain scheme for the full-discrete Maxwell's equations. We achieve a local and explicit time update for the field equations by employing the sparse approximate inverse (SPAI) algorithm. Interpolating field values to particles' positions for solving Newton-Lorentz equations of motion is also done via Whitney forms. Particles are advanced using the Boris algorithm with relativistic correction. A recently introduced charge-conserving scatter scheme tailored for 2D unstructured grids is used in the scatter step. The algorithm is validated considering cylindrical cavity and space-charge-limited cylindrical diode problems. We use the algorithm to investigate the physical performance of VEDs designed to harness particle bunching effects arising from the coherent (resonance) Cerenkov electron beam interactions within micro-machined slow wave structures.

  3. Effects of graphene coating and charge injection on water adsorption of solid surfaces. (United States)

    Guo, Yufeng; Guo, Wanlin


    The adhesion and cohesion of water molecules on graphene-coated and bare copper and mica substrates under charge injection have been extensively studied by first-principles calculations. Water adsorption on graphene-coated copper surface is weakened by injecting negative charges into the substrate, while enhanced by positive charges. Both negatively and positively charge injecting on graphene-coated mica strengthen the adsorption between water and the surface. While the adhesive and cohesive energies of water adsorption on charged bare copper and mica exhibit similar trends and much stronger response to charge injection. The charge sensitivity of water adsorbing on positively charged surfaces is significantly weakened by the graphene coating layer, mainly due to lower interfacial charge exchange. Our results suggest a viable way to modify water adsorption on a graphene-coated surface and unveil the role of graphene as a passivation layer for the wetting of a charged substrate.

  4. Formation of polyelectrolyte complexes with diethylaminoethyl dextran: charge ratio and molar mass effect. (United States)

    Le Cerf, Didier; Pepin, Anne Sophie; Niang, Pape Momar; Cristea, Mariana; Karakasyan-Dia, Carole; Picton, Luc


    The formation of polyelectrolyte complexes (PECs) between carboxymethyl pullulan and DEAE Dextran, was investigated, in dilute solution, with emphasis on the effect of charge density (molar ratio or pH) and molar masses. Electrophoretic mobility measurements have evidenced that insoluble PECs (neutral electrophoretic mobility) occurs for charge ratio between 0.6 (excess of polycation) and 1 (stoichiometry usual value) according to the pH. This atypical result is explained by the inaccessibility of some permanent cationic charge when screened by pH dependant cationic ones (due to the Hoffman alkylation). Isothermal titration calorimetry (ITC) indicates an endothermic formation of PEC with a binding constant around 10(5) L mol(-1). Finally asymmetrical flow field flow fractionation coupled on line with static multi angle light scattering (AF4/MALS) evidences soluble PECs with very large average molar masses and size around 100 nm, in agreement with scrambled eggs multi-association between various polyelectrolyte chains. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Secondary charging effects due to icy dust particle impacts on rocket payloads (United States)

    Kassa, M.; Rapp, M.; Hartquist, T. W.; Havnes, O.


    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.

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

    Directory of Open Access Journals (Sweden)

    M. Kassa


    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.

  7. Novel Charge Sensitive Amplifier Design Methodology suitable for Large Detector Capacitance Applications

    CERN Document Server

    Thomas Noulis a,; Gerard Sarrabayrouse b,c and; Laurent Bary b,c


    Current mode charge sensitive amplifier (CSA) topology and related methodology for use as pre-amplification block in radiation detection read out front end IC systems is proposed1. It is based on the use of a suitably configured current conveyor topology providing advantageous noise performance characteristics in comparison to the typical used CSA structures. In the proposed architecture the noise at the output of the CSA is independent of the detector capacitance value, allowing the use of large area detectors without affecting the system noise performance. Theoretical analysis and simulation analysis are performed concerning the operation – performance of the proposed topology. Measurement results on a current mode CSA prototype fabricated with a 0.35 μm CMOS process by Austriamicrosystems are provided supporting the theoretical and simulation results and confirming the performance mainly in terms of the noise performance dependency on the detector capacitance value.

  8. Effect of lipophilic ions on the intramembrane charge movement and intracellular Ca2+ release in fetal mouse skeletal muscle cells. (United States)

    Inoue, I; Shimahara, T; Bournaud, R


    The effects of lipophilic ions on the intramembrane charge movement and intracellular calcium transient were studied using freshly dissociated skeletal muscle cells from mice fetuses. The lipophilic cations Rhodamine 6G and tetraphenylphosphonium (TPP) immobilized part of the intramembrane charge movement in a dose-dependent manner, and inhibited both calcium transient and contraction evoked by membrane depolarization. In contrast, the lipophilic anion 1-anilinonaphthalene-8-sulfonic acid (ANS) had no effect on intramembrane charge movement. We suggest that the lipophilic cations block the voltage-sensing mechanism for the excitation-contraction (E-C) coupling mechanism.

  9. Present status and future subjects of the analytical studies related with application of charged particles and RI to materials science and biotechnology

    Energy Technology Data Exchange (ETDEWEB)



    The position in the research field of radiation application of Theoretical Analysis Group for Radiation Application' which will be set up within fiscal 2003, and the relation between the research that this analytical group will advance in future and the analytical research made so far at Takasaki Radiation Chemistry Establishment (JAERI, Takasaki) are summarized. Since the JAERI Takasaki was founded as the center of the research and development on radiation chemistry, a lot of outcomes have been obtained in the research and development of radiation application using large-sized {sup 60}Co gamma ray irradiation facilities and high power electron accelerators, etc. After the ion irradiation research facility (TIARA) started operation, many outstanding outcomes have been obtained in the research of up-to-date science and technologies in the fields of material science and bio-technology, etc., making use of ions in addition to gamma rays and electron beams. Although these results of the research are mainly produced experimentally, theoretical analyses also are thought to be important because these results will be applied and expanded in future. We aim to set up 'Theoretical Analysis Group for Radiation Application' in fiscal 2003, and we aim at performing theoretical and engineering analyses about phenomena and things such as radiation chemical reactions, irradiation/implantation effects to semiconductors, model for plant function, etc. The irradiation effects of charged particles to materials are divided into the primary effects like generation of radicals and lattice defects, etc., which occurs immediately after charged particles impinge on materials, and the secondary effects like chemical changes and physical changes caused in materials as a result of the primary effects. The subjects of our analytical research are the analyses of the secondary effects and the systems which utilize the chemical and the physical changes to the radiation application

  10. Influence of Bandstructure Effects on the Single-Charge-Induced Random Telegraphic Noise in Nanoscale FETs (United States)

    Islam, Sharnali; Ahmed, Shaikh


    Numerical simulations have been carried out to study the single-charge-induced random telegraphic noise in nanoscale field-effect transistors. A three-dimensional Monte Carlo device simulator has been developed and used in this work. Quantum effects have been accounted for via a parameter-free effective potential scheme that is based on a perturbation theory around thermodynamic equilibrium where the size of the electron depends upon its energy. For better accuracy, bandstructure parameters (bandgap, effective masses, and density of states) have been computed via a 20-band sp3d5s* tight-binding scheme. To treat full Coulomb interactions properly, two real-space molecular dynamics schemes have been implemented. Also, necessary event-biasing algorithms have been used that, while enhancing the statistics, results in a faster convergence in the channel current. The study confirms that, due to the presence of single channel charges, both the electrostatics (carrier density) and dynamics (mobility) get perturbed and, therefore, play important roles in determining the magnitude of the current fluctuations. The relative impact depends on an intricate interplay of device size, geometry, crystal direction, gate bias, temperature, and energetic and spatial location of the trap.

  11. Early-stage effects of residual charges in a metal target on emitted electrons induced by femtosecond laser–metal interactions

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Sha [Advanced Optowave Corp., Ronkonkoma, NY 11779 (United States); Wu, Benxin, E-mail: [School of Mechanical Engineering, Purdue University, 585 Purdue Mall, West Lafayette, IN 47907 (United States); Department of Mechanical, Materials, and Aerospace Engineering, Illinois Institute of Technology, Chicago, IL 60616 (United States)


    Electron emissions from a metal target surface may be induced due to the irradiation of the target by a femtosecond (fs) laser pulse. The emitted electrons will leave behind residual charges (which are positive) in the metal target near its surface. The residual charges may affect the evolution of the emitted electrons, which is called the “residual charge effect”. An intuitive belief could be that the residual charge effect is insignificant, because the huge number of free electrons in the interior region of the metal may quickly neutralize the residual charges. In this paper, the early-stage (at a time scale of less than ∼1 picosecond) residual charge effect has been investigated. The study shows that contrary to the above intuitive belief, the early-stage residual charge effect is very significant under the studied conditions, which has greatly slowed down the expansion of emitted electrons and enhanced their recombination back into the surface of the target. The study implies that to accurately study the early-stage fs laser-induced electron emission and other closely related processes, the residual charge effect should not be neglected. - Highlights: • Laser-induced electron emission may leave positive residual charges in a metal. • An intuitive belief could be that the residual charge effect is insignificant. • This study shows the residual charge effect is significant during the early stage. • The residual charge effect slows down the expansion of emitted electrons. • The residual charge effect enhances the recombination of emitted electrons.

  12. Enhancing gas induced charge doping in graphene field effect transistors by non-covalent functionalization with polyethyleneimine (United States)

    Sabri, Shadi S.; Guillemette, Jonathan; Guermoune, Abdelaadim; Siaj, Mohamed; Szkopek, Thomas


    We demonstrate that large-area, graphene field effect transistors with a passive parylene substrate and a polyethyleneimine functional layer have enhanced sensitivity to CO2 gas exposure. The electron doping of graphene, caused by protonated amine groups within the polyethyleneimine, is modulated by the formation of negatively charged species generated by CO2 adsorption. The charge doping mechanism is general, and quantitative doping density changes can be determined from the graphene field effect transistor characteristics.

  13. Plasma Effects On Atomic Data For The K-Vacancy States Of Highly Charged Iron Ions


    Deprince, J; Fritzsche, S; Kallman, T. R.; Palmeri, P; Quinet, Pascal


    The main goal of the present work is to estimate the effects of plasma environment on the atomic parameters associated with the K-vacancy states in highly charged iron ions within the astrophysical context of accretion disks around black holes. In order to do this, multiconfiguration Dirac-Fock computations have been carried out by considering a time averaged Debye-H\\"uckel potential for both the electron-nucleus and electron-electron interactions. In the present paper, a first sample of resu...

  14. Temperature and Magnetic Field Effects on the Transport Controlled Charge State of a Single Quantum Dot

    Directory of Open Access Journals (Sweden)

    Moskalenko ES


    Full Text Available Abstract Individual InAs/GaAs quantum dots are studied by micro-photoluminescence. By varying the strength of an applied external magnetic field and/or the temperature, it is demonstrated that the charge state of a single quantum dot can be tuned. This tuning effect is shown to be related to the in-plane electron and hole transport, prior to capture into the quantum dot, since the photo-excited carriers are primarily generated in the barrier.

  15. The effect of interfacial layers on charge transport in organic solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Mbuyise, Xolani G.; Tonui, Patrick; Mola, Genene Tessema, E-mail:


    The effect of interfacial buffer layers in organic photovoltaic cell (OPV) whose active layer is composed of poly(3 hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) blend was studied. The electrical properties of OPV devices produced with and without interfacial layers are compared and discussed in terms of measured parameters of the cells. The charge transport properties showed significant difference on the mobility and activation factor between the two types of device structures. The life time measurements in the unprotected conditions are also presented and discussed.

  16. Effect of spatial charge inhomogeneity on 1/f noise behavior in graphene. (United States)

    Xu, Guangyu; Torres, Carlos M; Zhang, Yuegang; Liu, Fei; Song, Emil B; Wang, Minsheng; Zhou, Yi; Zeng, Caifu; Wang, Kang L


    Scattering mechanisms in graphene are critical to understanding the limits of signal-to-noise ratios of unsuspended graphene devices. Here we present the four-probe low-frequency noise (1/f) characteristics in back-gated single layer graphene (SLG) and bilayer graphene (BLG) samples. Contrary to the expected noise increase with the resistance, the noise for SLG decreases near the Dirac point, possibly due to the effects of the spatial charge inhomogeneity. For BLG, a similar noise reduction near the Dirac point is observed, but with a different gate dependence of its noise behavior. Some possible reasons for the different noise behavior between SLG and BLG are discussed.

  17. VersiCharge-SG - Smart Grid Capable Electric Vehicle Supply Equipment (EVSE) for Residential Applications

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Dong [National Renewable Energy Lab. (NREL), Golden, CO (United States); Haas, Harry [National Renewable Energy Lab. (NREL), Golden, CO (United States); Terricciano, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States)


    (NREL) shows that an increased PEV penetration would significantly increase pressure on the peak generation, if no controlled charging strategy was put in place. Investigations from Oak Ridge National Laboratory (ORNL) show that in many regions, additional power generation facilities must be put in place and operate in evening times to recharge the EVs [12]. By all accounts, large PEV penetration will bring to the power grid enormous challenges due to the excessive and stochastic demand, and can entirely change the peak time distribution and behavior, perhaps, into a bi-modal distribution capable of exhausting primary, secondary and even reserves (spinning or non-spinning). To minimize the infrastructure upgrade costs and risks to the grid, and to ensure that power quality and reliability remain within the set standards, the demand for EV plug-ins must then be controlled and coordinated locally and at regional levels. Novel control techniques must be devised to allow for close collaboration between neighboring plug-in requestors, between neighboring communities, and between these and more central power authorities. The concept of electric drive vehicle is not new. The development of electric vehicle has been around since 19th century [13]. But due to a number of reasons and practical limitations at the time, including lower cost of gasoline compared to electricity, excessive refueling times, and abundance of gasoline, the automobile industry embraced gasoline-powered vehicles worldwide [13]. With the global warming, ever reducing reservoirs of fossil oil around the world and increasing political pressure to reduce the national dependency on foreign oil, the last decade of the 20th century witnessed major technological breakthroughs in Alternative Fueled Vehicle (AFV) technologies, including electric vehicles. With GHG emissions and carbon footprint in the minds of many more consumers and politicians, the first decade of the 21stCentury witnessed more breakthroughs with

  18. Deuterium isotope effects on 13C chemical shifts of negatively charged NH.N systems

    DEFF Research Database (Denmark)

    Hansen, Poul Erik; Pietrzak, Mariusz; Grech, Eugeniusz


    ” and equilibrium cases. NMR assignments of the former have been revised. The NH proton is deuteriated. The isotope effects on 13C chemical shifts are rather unusual in these strongly hydrogen bonded systems between a NH and a negatively charged nitrogen atom. The formal four-bond effects are found to be negative......Deuterium isotope effects on 13C chemical shifts are investigated in anions of 1,8-bis(4-toluenesulphonamido)naphthalenes together with N,N-(naphthalene-1,8-diyl)bis(2,2,2-trifluoracetamide) all with bis(1,8-dimethylamino)napthaleneH+ as counter ion. These compounds represent both “static...... indicating transmission via the hydrogen bond. In addition, unusual long range effects are seen. Structures, 1H and 13C NMR chemical shifts and changes in nuclear shieldings upon deuteriation are calculated using density functional theory methods...

  19. Hamiltonian and Lagrangian dynamics of charged particles including the effects of radiation damping (United States)

    Qin, Hong; Burby, Joshua; Davidson, Ronald; Fisch, Nathaniel; Chung, Moses


    The effects of radiation damping (radiation reaction) on accelerating charged particles in modern high-intensity accelerators and high-intensity laser beams have becoming increasingly important. Especially for electron accelerators and storage rings, radiation damping is an effective mechanism and technique to achieve high beam luminosity. We develop Hamiltonian and Lagrangian descriptions of the classical dynamics of a charged particle including the effects of radiation damping in the general electromagnetic focusing channels encountered in accelerators. The direct connection between the classical Hamiltonian and Lagrangian theories and the more fundamental QED description of the synchrotron radiation process is also addressed. In addition to their theoretical importance, the classical Hamiltonian and Lagrangian theories of the radiation damping also enable us to numerically integrate the dynamics using advanced structure-preserving geometric algorithms. These theoretical developments can also be applied to runaway electrons and positrons generated during the disruption or startup of tokamak discharges. This research was supported by the U.S. Department of Energy (DE-AC02-09CH11466).

  20. Interactions of amino acids with adatoms(Ti, C, O) decorated graphene via effect of charging (United States)

    Salmankurt, Bahadır; Gürel, Hikmet Hakan


    As amino acids take an important role in biology, it is envisaged that understanding of their interactions with nanomate-rials can resolve critical problems in the field of biomedicine. Graphene, single atom thick hexagonal lattice of sp2-bonded carbon, can be used for this purpose. The remarkable properties of graphene sheets could facilitate their application in areas like hydrogen technology, electronics, and sensing. In this work, we report density functional theory calculations of the adsorption of Histidine and Leucine molecules on pristine and decorated (Ti,C and O) graphene. The obtained binding energies of molecules on graphene surface are in good agreement previous studies. The chemisorption is achieved when Graphene is decorated with Ti and C. It is also shown that how modify structural properties of the molecules on pristine Graphene by applied charging for the first time.

  1. Evaluation of charge-sharing effects on the spatial resolution of the PICASSO detector

    Energy Technology Data Exchange (ETDEWEB)

    Rigon, L., E-mail: luigi.rigon@ts.infn.i [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Trieste, Via Valerio 2, 34127 Trieste (Italy); Arfelli, F. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Trieste, Via Valerio 2, 34127 Trieste (Italy); Dipartimento di Fisica, Universita di Trieste, Via Valerio 2, 34127 Trieste (Italy); Bergamaschi, A. [Paul Scherrer Institut (PSI), CH-5232 Villigen (Switzerland); Chen, R.C. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Trieste, Via Valerio 2, 34127 Trieste (Italy); Shanghai Institute of Applied Physics, CAS, Shanghai 201800 (China); Dreossi, D. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Trieste, Via Valerio 2, 34127 Trieste (Italy); Sincrotrone Trieste SCpA, S.S. 14 km 163.5, 34012 Basovizza (Italy); Longo, R. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Trieste, Via Valerio 2, 34127 Trieste (Italy); Dipartimento di Fisica, Universita di Trieste, Via Valerio 2, 34127 Trieste (Italy); Menk, R.-H. [Sincrotrone Trieste SCpA, S.S. 14 km 163.5, 34012 Basovizza (TS) (Italy); Schmitt, B. [Paul Scherrer Institut (PSI), CH-5232 Villigen (Switzerland); Vallazza, E. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Trieste, Via Valerio 2, 34127 Trieste (Italy); Castelli, E. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Trieste, Via Valerio 2, 34127 Trieste (Italy); Dipartimento di Fisica, Universita di Trieste, Via Valerio 2, 34127 Trieste (Italy)


    A double -layer 'edge-on' silicon microstrip detector has been designed and realized in the frame of the PICASSO (Phase Imaging for Clinical Application with Silicon detector and Synchrotron radiatiOn) project at the SYRMEP (SYnchrotron Radiation for MEdical Physics) beamline of Elettra (Trieste, Italy). The detector meets the requirements for synchrotron radiation mammography with patients inregarding: (a) size, since it covers the full beam width (210 mm); (b) spatial resolution, determined by the 0.05 mm strip pitch; (c) single-photon counting capabilities, because it is able to handle more than 10{sup 6} photons/(pixelxs); (d) contrast resolution, thanks to a threshold trim DAC that equalizes the channel sensitivity; (e) efficiency, due to the high absorption in the 15-20 mm sensor depth. Experimental measurements evidence charge sharing, though not compromising the spatial resolution.

  2. Flow cytometry evidence of human granulocytes interaction with polyhedral oligomeric silsesquioxanes: effect of nanoparticle charge (United States)

    Renò, Filippo; Carniato, Fabio; Rizzi, Manuela; Olivero, Francesco; Pittarella, Pamela; Marchese, Leonardo


    Nanoparticles (NPs) entering the human body are immediately confronted with the innate part of human immune system. In particular, monocyte and neutrophil granulocytes readily clear particles by phagocytosis, even if in the case of NPs the uptake mechanism may be classified as macropinocytosis. Among engineered nanoparticles, in the last years, siliceous materials have emerged as promising materials for several applications ranging from catalysis to biomedical. The polyhedral oligomeric silsesquioxanes (POSS) are nanodimensional, easily synthesizable molecular compounds and POSS-based systems are promising carriers for biological molecules. In this work, the ability of human granulocytes to uptake positively and negatively charged POSS was measured using a simple flow cytometry analysis based on cell size modifications. The data obtained showed that after a 30 min exposure only positive NPs were uptaken by human granulocyte using both macropinocytosis and clathrin-mediated mechanisms as demonstrated by uptake inhibition mediated by amiloride and chlorpromazine.

  3. Evaluation of charge -sharing effects on the spatial resolution of the PICASSO detector (United States)

    Rigon, L.; Arfelli, F.; Bergamaschi, A.; Chen, R. C.; Dreossi, D.; Longo, R.; Menk, R.-H.; Schmitt, B.; Vallazza, E.; Castelli, E.


    A double -layer "edge-on" silicon microstrip detector has been designed and realized in the frame of the PICASSO (Phase Imaging for Clinical Application with Silicon detector and Synchrotron radiatiOn) project at the SYRMEP (SYnchrotron Radiation for MEdical Physics) beamline of Elettra (Trieste, Italy). The detector meets the requirements for synchrotron radiation mammography with patients inregarding: (a) size, since it covers the full beam width (210 mm); (b) spatial resolution, determined by the 0.05 mm strip pitch; (c) single-photon counting capabilities, because it is able to handle more than 10 6 photons/(pixel×s); (d) contrast resolution, thanks to a threshold trim DAC that equalizes the channel sensitivity; (e) efficiency, due to the high absorption in the 15-20 mm sensor depth. Experimental measurements evidence charge sharing, though not compromising the spatial resolution.

  4. Characterization of the charge-carrier transport properties of IIa-Tech SC diamond for radiation detection applications

    Energy Technology Data Exchange (ETDEWEB)

    Pomorski, M.; Delfaure, C.; Tromson, D.; Bergonzo, P. [CEA, LIST, Diamond Sensors Laboratory, Gif-sur-Yvette (France); Vaissiere, N.; Bensalah, H.; Barjon, J.; Pinault-Thaury, M.A. [Groupe d' Etude de la Matiere Condensee (GEMaC), Centre National de la Recherche Scientifique, Universite de Versailles Saint Quentin en Yvelines (UVSQ), Versailles (France)


    Single crystal (SC) diamond has since years demonstrated its interest for the fabrication of radiation detectors, especially where the material properties are providing superior interests with respect to the detection application. Among the industrial suppliers able to provide on a commercial basis high-grade single crystal diamond, IIa-Tech has recently appeared in the market as a new player. The aim of this paper is to assess the quality of one SC sample when characterized under α-particles for the measurement of its carrier transport properties. We observed that full charge collection could be observed at biases as low as 0.11 V/μm with no space charge build-up (conventionally typical bias values used are closer to 1 V/μm). Velocity reached values of 38 μm/ns and 53 μm/ns for electrons and holes, respectively (values probed at 0.33 V/μm). Similarly, the α detection spectrum displays a sharp line demonstrating the good uniformity of the material over its surface. By combining the measurements with more conventional optical observations such as birefringence and cathodoluminescence spectroscopy, it comes that the material demonstrates its ability to be used as a detector, with properties that can compare with the highest grade materials today available on the market. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Light-erasable embedded charge-trapping memory based on MoS2 for system-on-panel applications (United States)

    He, Long-Fei; Zhu, Hao; Xu, Jing; Liu, Hao; Nie, Xin-Ran; Chen, Lin; Sun, Qing-Qing; Xia, Yang; Wei Zhang, David


    The continuous scaling and challenges in device integrations in modern portable electronic products have aroused many scientific interests, and a great deal of effort has been made in seeking solutions towards a more microminiaturized package assembled with smaller and more powerful components. In this study, an embedded light-erasable charge-trapping memory with a high-k dielectric stack (Al2O3/HfO2/Al2O3) and an atomically thin MoS2 channel has been fabricated and fully characterized. The memory exhibits a sufficient memory window, fast programming and erasing (P/E) speed, and high On/Off current ratio up to 107. Less than 25% memory window degradation is observed after projected 10-year retention, and the device functions perfectly after 8000 P/E operation cycles. Furthermore, the programmed device can be fully erased by incident light without electrical assistance. Such excellent memory performance originates from the intrinsic properties of two-dimensional (2D) MoS2 and the engineered back-gate dielectric stack. Our integration of 2D semiconductors in the infrastructure of light-erasable charge-trapping memory is very promising for future system-on-panel applications like storage of metadata and flexible imaging arrays.

  6. Structural characterisation of Arquad® 2HT-75 organobentonites: surface charge characteristics and environmental application. (United States)

    Sarkar, Binoy; Megharaj, Mallavarapu; Xi, Yunfei; Naidu, Ravi


    Organoclays are increasingly being used to remediate both contaminated soils and waste water. The present study was attempted to elucidate the structural evolution of bentonite based organoclays prepared from a commercially available, low-cost alkyl ammonium surfactant Arquad(®) 2HT-75. XRD, FTIR, SEM and zeta potential measurement were used to characterise the organoclays. In particular, the relationship between surface charge characteristics of the organoclays and their ability to remediate organic contaminants such as phenol and p-nitrophenol was investigated. The investigation revealed that the arrangement and conformation of surfactant molecules in the bentonite became more regular, ordered and solid-like as of Arquad(®) 2HT-75 loading increased. This also led to the formation of a positive zeta potential on the surface of organobentonites prepared with 3.57:1 and 4.75:1 surfactant-clay (w/w) ratio. The zeta potential values decreased with increasing pH of the suspension. The adsorption data of phenol and p-nitrophenol were best fitted to Freundlich isotherm model. The adsorption was controlled by multiple mechanisms of partitioning, physico-sorption and chemisorption. The outcomes of this study are useful for the synthesis of low cost organobentonite adsorbents for the remediation of ionisable organic contaminants such as phenol and p-nitrophenol from waste water. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Sizing Dynamic Wireless Charging for Light-Duty Electric Vehicles in Roadway Applications

    Energy Technology Data Exchange (ETDEWEB)

    Foote, Andrew P [ORNL; Ozpineci, Burak [ORNL; Chinthavali, Madhu Sudhan [ORNL; Li, Jan-Mou [ORNL


    Dynamic wireless charging is a possible cure for the range limitations seen in electric vehicles (EVs) once implemented in highways or city streets. The contribution of this paper is the use of experimental data to show that the expected energy gain from a dynamic wireless power transfer (WPT) system is largely a function of average speed, which allows the power level and number of coils per mile of a dynamic WPT system to be sized for the sustained operation of an EV. First, data from dynamometer testing is used to determine the instantaneous energy requirements of a light-duty EV. Then, experimental data is applied to determine the theoretical energy gained by passing over a coil as a function of velocity and power level. Related simulations are performed to explore possible methods of placing WPT coils within roadways with comparisons to the constant velocity case. Analyses with these cases demonstrate what system ratings are needed to meet the energy requirements of the EV. The simulations are also used to determine onboard energy storage requirements for each driving cycle.

  8. Molecular semiconductor blends: microstructure, charge carrier transport and application in photovoltaic cells

    Energy Technology Data Exchange (ETDEWEB)

    Opitz, Andreas; Wagner, Julia; Ecker, Bernhard; Bruetting, Wolfgang [Institute of Physics, University of Augsburg (Germany); Hinderhofer, Alexander; Schreiber, Frank [Institute of Applied Physics, University of Tuebingen (Germany)


    Blends of organic donor and acceptor materials have the potential of an increase of solar cell efficiency. However, the balance between charge carrier transport in phase-separated structures and exciton dissociation at the donor-acceptor interface has to be optimized. To analyze this relation in more detail the following molecular material combinations were investigated: (i) Copper phthalocyanine (CuPc) combined with fullerene C{sub 60} and (ii) CuPc in combination with perfluorinated CuPc (F{sub 16}CuPc). Measurements by X-ray diffraction and scanning force microscopy indicate the formation of phase-separated nanocrystals for blends of CuPc/C{sub 60} and the formation of mixed crystals in the CuPc/F{sub 16}CuPc system. The formation of mixed crystals is an interesting feature for organic blends which has not yet been explored in organic solar cells. We will discuss the implications of the different molecular arrangements on the optical and electrical properties as well as for the solar cell performance.

  9. An Assessment of Grid-Charged Inverter-Battery Systems for Domestic Applications in Ghana

    Directory of Open Access Journals (Sweden)

    David A. Quansah


    Full Text Available Ghana, like many African countries, is currently facing power supply shortage, which has led to load shedding. To minimize the impact of the power crisis, options such as diesel and petrol generators, grid-charged battery-inverter systems (GBIS, and solar PV with battery storage (SPVS have been used in residential and nonresidential contexts. In this paper, we develop analytical models to conduct a technical and economic comparison of GBIS and SPVS systems. Using average electricity tariff of $0.186 for residential sector (excluding lifeline customers we show that although initial cost of SPVS is higher, it costs 30% less than GBIS. We also show that losses associated with the GBIS are as high as 42% when viewed from a systems perspective and that some of its costs are externalized. We conclude by commending the Ghana Government’s initiative of rolling out 200,000 residential rooftop solar systems and recommend an increase in system capacities as well as a similar programme for nonresidential facilities.

  10. Hydrogen bonded charge transfer molecular salt (4-chloro anilinium-3-nitrophthalate) for photophysical and pharmacological applications (United States)

    Singaravelan, K.; Chandramohan, A.; Saravanabhavan, M.; Muthu Vijayan Enoch, I. V.; Suganthi, V. S.


    Radical scavenging activity against DPPH radical and binding properties of a hydrogen bonded charge transfer molecular salt 4-chloro anilinium-3-nitrophthalate(CANP) with calf thymus DNA has been studied by electronic absorption and emission spectroscopy. The molecular structure and crystallinity of the CANP salt have been established by carried out powder and single crystal X-ray diffraction analysis which indicated that cation and anion are linked through strong N+sbnd H…O- type of hydrogen bond. FTIR spectroscopic study was carried out to know the various functional groups present in the crystal. 1H and 13C NMR spectra were recorded to further confirm the molecular structure of the salt crystal. The thermal stability of the title salt was established by TG/DTA analyses simultaneously on the powdered sample of the title crystal. Further, the CANP salt was examined against various bacteria and fungi strains which showed a remarkable antimicrobial activity compared to that of the standards Ciproflaxin and Clotrimazole. The results showed that the CANP salt could interact with CT-DNA through intercalation. Antioxidant studies of the substrates alone and synthesized CANP salt showed that the latter has been better radical scavenging activity than that of the former against DPPH radical. The third order nonlinear susceptibility of the CANP salt was established by the Z-scan study.

  11. Removal of pollutants by enhanced coagulation combined PAC with variable charge soils: flocs' properties and effect of pH. (United States)

    Wang, Yu-Jie; Wu, Chun-De; Duan, Yan; Zhang, Zhi-Lin


    This study investigated the properties of flocs and effects of the solution pH on removal of representative pollutants by enhanced coagulation with variable charge soils of South China and polyaluminum chloride (PAC). The results demonstrated that the removal efficiency of turbidity was larger and the aggregated flocs had a faster growth rate, bigger size, denser structure and faster settling rate than those generated by PAC alone, when variable charge soil was used in conjunction with PAC. Additionally, initial solutions pH had meaningful effects on removal of pollutants. With the increase in the pH of the solution, the removal efficiencies of turbidity, algae and heavy metal ions significantly increased. Besides, charge neutralization together with physical entrapment of colloids was the dominant mechanism in enhanced coagulation, and variable charge soil displayed a great adsorption effect.

  12. Experimental evaluation of refrigerant mass charge and ambient air temperature effects on performance of air-conditioning systems (United States)

    Deymi-Dashtebayaz, Mahdi; Farahnak, Mehdi; Moraffa, Mojtaba; Ghalami, Arash; Mohammadi, Nima


    In this paper the effects of refrigerant charge amount and ambient air temperature on performance and thermodynamic condition of refrigerating cycle in the split type air-conditioner have been investigated. Optimum mass charge is the point at which the energy efficiency ratio (EER) of refrigeration cycle becomes the maximum. Experiments have been conducted over a range of refrigerant mass charge from 540 to 840 g and a range of ambient temperature from 27 to 45 °C, in a 12,000 Btu/h split air-conditioner as case study. The various parameters have been considered to evaluate the cooling rate, energy efficiency ratio (EER), mass charge effect and thermodynamic cycle of refrigeration system with R22 refrigerant gas. Results confirmed that the lack of appropriate refrigerant mass charge causes the refrigeration system not to reach its maximum cooling capacity. The highest cooling capacity achieved was 3.2 kW (11,000 Btu/h). The optimum mass charge and corresponding EER of studied system have been obtained about 640 g and 2.5, respectively. Also, it is observed that EER decreases by 30% as ambient temperature increases from 27 °C to 45 °C. By optimization of the refrigerant mass charge in refrigerating systems, about 785 GWh per year of electric energy can be saved in Iran's residential sector.

  13. Analysis of capacity fading effect on Lithium Cobalt cells caused by pulse current technique in fast charging methods (United States)

    Hafiz, S.; Arianto, S.; Yunaningsih, R. Y.; Majid, N.; Prihandoko, B.


    Charging a battery in a short time is important for portable devices. Many techniques have been developed to find out the proper method for fast charging. One of those techniques that has been patented in several fast charging methods is pulse current technique. This technique implements pulse current with adjusting pulse wide and voltage threshold in a certain values. In this paper, the capacity fading effects caused by the current pulse in lithium cobalt cells were investigated. The experiment was done by applying pulse current at high-level SOC to charge four cylindrical lithium cobalt cells. The Capacity of each cell was checked every 50 charge-discharge cycles. The experiment result shows that the changing capacity in each cell forms patterns alike. As if there was a slight increament on their capacities at first checking but rapidly decreasing at the next check. Then, their capacities continue to decrease slowly but the more often the charge-discharge cycling, the battery lifetime decreased. This research has provided analysis of pulse current effect on lithium cobalt capacity fading that should be noted as a reference in applying current pulse for fast charging methods.

  14. Effect of the Net Charge Distribution on the Aqueous Solution Properties of Polyampholytes Effet de la répartition de la charge nette sur les propriétés des solutions aqueuses de polyampholytes

    Directory of Open Access Journals (Sweden)

    Candau F.


    Full Text Available The zwitterion nature of ampholytic polymers provides features that are useful in environmental and industrial applications, e. g. ion-exchange membrane, as flocculants in sewage treatment and in oil recovery processes. In the latter case, the increase in viscosity which is observed in the presence of brine (anti -polyelectrolyte behavior make them ideal candidates for high salinity media. The aqueous solution properties of a series of ampholytic terpolymers based on sodium-2-acrylamido-2- rilethylpropanesulfonate (NaAMPS, Methacryloyloxyethyltrimethylammonium chloride (MADQUAT and acrylamide (AM, prepared in inverse micro emulsions have been investigated by viscometry and light scattering experiments. The distribution of the net charge among the chains was varied by adjusting the initial monomer composition and the degree of conversion. The effect of this distribution on the solubility of the samples and on the chain conformation was studied. It was found that samples with a narrow distribution of net charges were soluble in water even if the average net charge is small. Addition of salt produces a transition from an extended conformation to a more compact one in qualitative agreement with theoretical predictions. A practically alternated NaAMPS- MADQUAT copolymer prepared in homogeneous solution and with a small average net charge shows a behaviour quite similar to that of the terpolymers. La nature zwitterioniquedes polymères ampholytes présente des caractéristiques qui sont utiles dans les applications environnementales et industrielles, comme les membranes d'échange ionique, les floculants dans le traitement des eaux usées et dans les procédés de récupération de pétrole. Dans ce dernier cas, l'augmentation de viscosité qui est observée en présence de saumure (comportement antipolyélectrolyte en fait des candidats idéaux pour des milieux de salinité élevée. Les propriétés de la solution aqueuse d'une série de terpolym

  15. Mesoporous gold sponges: electric charge-assisted seed mediated synthesis and application as surface-enhanced Raman scattering substrates (United States)

    Yi, Zao; Luo, Jiangshan; Tan, Xiulan; Yi, Yong; Yao, Weitang; Kang, Xiaoli; Ye, Xin; Zhu, Wenkun; Duan, Tao; Yi, Yougen; Tang, Yongjian


    Mesoporous gold sponges were prepared using 4-dimethylaminopyridine (DMAP)-stabilized Au seeds. This is a general process, which involves a simple template-free method, room temperature reduction of HAuCl4·4H2O with hydroxylamine. The formation process of mesoporous gold sponges could be accounted for the electrostatic interaction (the small Au nanoparticles (~3 nm) and the positively charged DMAP-stabilized Au seeds) and Ostwald ripening process. The mesoporous gold sponges had appeared to undergo electrostatic adsorption initially, sequentially linear aggregation, welding and Ostwald ripening, then, they randomly cross link into self-supporting, three-dimensional networks with time. The mesoporous gold sponges exhibit higher surface area than the literature. In addition, application of the spongelike networks as an active material for surface-enhanced Raman scattering has been investigated by employing 4-aminothiophenol (4-ATP) molecules as a probe.

  16. Testing quantum gravity effects through Dyonic charged AdS black hole

    CERN Document Server

    Sadeghi, J; Rostami, M


    In this paper, we consider dyonic charged AdS black hole which is holographic dual of a van der Waals fluid. We use logarithmic corrected entropy and study thermodynamics of the black hole and show that holographic picture is still valid. Critical behaviors and stability also discussed. Logarithmic corrections arises due to thermal fluctuations which are important when size of black hole be small. So, thermal fluctuations interpreted as quantum effect. It means that we can see quantum effect of a black hole which is a gravitational system. Hence, one can use result of this paper to compare with that of van der Waals fluid in the lab and see quantum gravity effects.

  17. Simulation study of the photoemission effects in an electrostatic plasma sheath containing charged nanoparticles (United States)

    Jalilpour, P.; Foroutan, G.


    Numerical simulations of the multi-fluid equations are utilized to investigate the effects of a directed photon flux on the structure of an electrostatic plasma sheath in the presence of nano-sized dust grains. The results revealed that the sheath width decreases with an increase in the photon flux as well as the photoelectric efficiency, and that the effect is prominent at high plasma number densities. With the increase in the incident flux, the absolute dust charge decreases immediately until it changes sign and becomes positive at moderate fluxes and then increases quite slowly. The ion drag is also reduced by the photoemission, while the electric force is enhanced. The net effect is an enhancement of the total force on the dust grains towards the sheath edge, leading to a significantly reduced dust speed and consequently an increased dust number density throughout the sheath.

  18. Effect of electrostatic charge on the contamination of plastic food containers by airborne bacterial spores. (United States)

    Baribo, L E; Avens, J S; O'neill, R D


    Electrostatic charge of approximately -10 kv was produced by friction on polystyrene food container samples. This charge quickly decayed to a lower, more stable, level. Exposure of samples to positively charged red and negatively charged green fluorescent particles resulted in a particle-distribution pattern on the plastic surface. The dynamic attraction of fluorescent particles was illustrated by time-lapse photography. Similar distribution patterns of airborne bacterial spores were shown to develop. In controlled bacterial aerosol exposure tests, an increase in surface contamination of the plastic samples was found to be quantitatively related to an increase in negative electrostatic charge on the plastic. Static charge was found to accumulate on plastic food containers during their manufacture, and to remain indefinitely on many of the finished products. This charge was of the intensity and polarity to attract positively charged bacterial cells if such particles were present in the air.

  19. Photo-excited charge collection spectroscopy probing the traps in field-effect transistors

    CERN Document Server

    Im, Seongil; Kim, Jae Hoon


    Solid state field-effect devices such as organic and inorganic-channel thin-film transistors (TFTs) have been expected to promote advances in display and sensor electronics. The operational stabilities of such TFTs are thus important, strongly depending on the nature and density of charge traps present at the channel/dielectric interface or in the thin-film channel itself. This book contains how to characterize these traps, starting from the device physics of field-effect transistor (FET). Unlike conventional analysis techniques which are away from well-resolving spectral results, newly-introduced photo-excited charge-collection spectroscopy (PECCS) utilizes the photo-induced threshold voltage response from any type of working transistor devices with organic-, inorganic-, and even nano-channels, directly probing on the traps. So, our technique PECCS has been discussed through more than ten refereed-journal papers in the fields of device electronics, applied physics, applied chemistry, nano-devices and materia...

  20. Wireless Energy Transfer Using Resonant Magnetic Induction for Electric Vehicle Charging Application (United States)

    Dahal, Neelima

    The research work for this thesis is based on utilizing resonant magnetic induction for wirelessly charging electric vehicles. The background theory for electromagnetic induction between two conducting loops is given and it is shown that an RLCequivalent circuit can be used to model the loops. An analysis of the equivalent circuit is used to show how two loosely coupled loops can be made to exchange energy efficiently by operating them at a frequency which is the same as the resonant frequency of both. Furthermore, it is shown that the efficiency is the maximum for critical coupling (determined by the quality factors of the loops), and increasing the coupling beyond critical coupling causes double humps to appear in the transmission efficiency versus frequency spectrum. In the experiment, as the loops are brought closer together which increases the coupling between them, doubles humps, as expected from the equivalent circuit analysis is seen. Two models for wireless energy transfer are identified: basic model and array model. The basic model consists of the two loosely coupled loops, the transmitter and the receiver. The array model consists of a 2 x 2 array of the transmitter and three parasites, and the receiver. It is shown that the array model allows more freedom for receiver placement at the cost of degraded transmission efficiency compared to the basic model. Another important part of the thesis is software validation. HFSS-IE and 4NEC2 are the software tools used and the simulation results for wire antennas are compared against references obtained from a textbook and a PhD dissertation. It is shown that the simulations agree well with the references and also with each other.

  1. Astrophysical Applications for Charge-Exchange with H, He, and H2 Targets (United States)

    Cumbee, Renata S.; Mullen, Patrick D.; Shelton, Robin L.; Schultz, David R.; Stancil, Phillip C.


    When a hot plasma collides with a cold neutral gas, interactions occur between the constituents at the interface of the collision, including charge exchange (CX). CX is a process in which an electron can be transferred from a neutral atom or molecule into an excited energy level of an ion. Following this transfer, the excited electron relaxes to lower energy levels, emitting X-rays. This process has been established as a primary source of X-ray emission within our solar system, such as when the solar wind interacts with cometary and planetary atmospheres, and outside of our solar system, such as in the hot outflows of starburst galaxies.As the CX X-ray emission spectrum varies greatly with collision velocity, it is critical that realistic CX data are included in X-ray spectral models in regions in which CX might be significant so that the ion abundance and plasma velocities can be estimated most accurately. Here, a set of CX X-ray line ratios and spectra will be shown for a variety of collision velocities for C-Cl ions colliding with H, He, and H2. An X-ray emission model including these line ratios performed in XSPEC will be presented for a region of the Cygnus Loop supernova remnant and the starburst galaxy M82 in order to highlight the variation in CX spectral models with collision energy and neutral target species.R. Cumbee’s research was partially supported by an appointment to the NASA Postdoctoral Program at NASA GSFC, administered by Universities Space Research Association under contract with NASA. Work at UGA was partially supported by NASA grants NNX09AC46G and NNG09WF24I.

  2. Charge is an important determinant of hemodynamic and adverse cardiovascular effects of cationic drugs. (United States)

    Pugsley, Michael K; Authier, Simon; Curtis, Michael J


    Cationic compounds are diverse and atypical therapeutic substances. In the present study we examined whether a prototypical class effect of cationic drugs in the cardiovascular system exists and whether this might be predictable on the basis of chemistry. The dose-dependent effects of cationic compounds of varying molecular weights and charge were examined on the blood pressure (BP), heart rate (HR) and the ECG in anesthetized rats. The compounds examined were protamine, hexadimethrine, tetraethylammonium (TEA), low molecular weight poly-L-lysine (LMW-PLL) and high molecular weight PLL (HMW-PLL). All of the compounds examined except TEA produced a dose-dependent reduction in BP. No changes occurred in HR even when high doses were administered. The ECG effects of these cationic compounds included a dose-dependent prolongation of the QT interval, especially at higher doses. All compounds transiently decreased the size of the P-wave after i.v. bolus administration whereas only protamine and hexadimethrine prolonged the PR and QRS intervals and only at the highest dose (32 mg/kg) administered. All cationic compounds, except TEA and saline, evoked ventricular premature beats (VPB), and protamine and HMW-PLL also evoked brief episodes of ventricular tachycardia (VT). The incidence and frequency of arrhythmias was not dose-dependent and no animals experienced protracted episodes of arrhythmia incidence. These dose dependent effects of the polycationic compounds tested suggest a collective mechanism of action that relates the effect of charge of the compound to the onset and persistence of observed cardiovascular toxicity, and adverse cardiovascular effect risk appears to be predictable on this basis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Charge Exchange X-Ray Emission due to Highly Charged Ion Collisions with H, He, and H2: Line Ratios for Heliospheric and Interstellar Applications (United States)

    Cumbee, R. S.; Mullen, P. D.; Lyons, D.; Shelton, R. L.; Fogle, M.; Schultz, D. R.; Stancil, P. C.


    The fundamental collisional process of charge exchange (CX) has been established as a primary source of X-ray emission from the heliosphere, planetary exospheres, and supernova remnants. In this process, X-ray emission results from the capture of an electron by a highly charged ion from a neutral atom or molecule, to form a highly excited, high-charge state ion. As the captured electron cascades down to the lowest energy level, photons are emitted, including X-rays. To provide reliable CX-induced X-ray spectral models to realistically simulate these environments, line ratios and spectra are computed using theoretical CX cross sections obtained with the multi-channel Landau-Zener, atomic-orbital close-coupling, molecular-orbital close-coupling, and classical trajectory Monte Carlo methods for various collisional velocities relevant to astrophysics. X-ray spectra were computed for collisions of bare and H-like C to Al ions with H, He, and H2 with results compared to available experimental data. Using these line ratios, XSPEC models of CX emission in the northeast rim of the Cygnus Loop supernova remnant and the heliosphere are shown as examples with ion velocity dependence.

  4. Molecular Design and Device Application of Radical Polymers for Improved Charge Extraction in Organic Photovoltaic Cells (United States)


    practical applications currently. Furthermore, we anticipate that their utilization will expand as we continue our work regarding the the range of 5 kg mol-1 and 24 kg mol-1, as measured by size exclusion chromatography (SEC) against polystyrene (PS) standards. Furthermore...was the case in previous reports where polystyrene (PS) was utilized as the second block of a PTMA-based diblock copolymer. The SEC traces of the PDMS

  5. Simulations of the THz spectrum of liquid water incorporating the effects of intermolecular charge fluxes through hydrogen bonds

    Energy Technology Data Exchange (ETDEWEB)

    Torii, Hajime, E-mail: [Department of Chemistry, Faculty of Education, and Department of Optoelectronics and Nanostructure Science, Graduate School of Science and Technology, Shizuoka University, 836 Ohya, Shizuoka 422-8529 (Japan)


    The intensity of the band at ∼200 cm{sup −1} (∼6 THz) in the Terahertz spectrum of liquid water mainly arises from the modulations of the extent of intermolecular charge transfer through hydrogen bonds, called intermolecular charge fluxes, occurring upon molecular translations along the O…H hydrogen bonds. To obtain reasonable spectral profiles from simulations, it is necessary to effectively incorporate the effects of those intermolecular charge fluxes, but apparently it is not possible by simple classical molecular dynamics simulations with fixed atomic partial charges even if they are amended by molecular induced dipoles due to intermolecular electrostatic interactions. The present paper shows how we can do reasonably correct spectral simulations, without resorting to fully ab initio molecular dynamics.

  6. Charge-Shift Corrected Electronegativities and the Effect of Bond Polarity and Substituents on Covalent-Ionic Resonance Energy. (United States)

    James, Andrew M; Laconsay, Croix J; Galbraith, John Morrison


    Bond dissociation energies and resonance energies for HnA-BHm molecules (A, B = H, C, N, O, F, Cl, Li, and Na) have been determined in order to re-evaluate the concept of electronegativity in the context of modern valence bond theory. Following Pauling's original scheme and using the rigorous definition of the covalent-ionic resonance energy provided by the breathing orbital valence bond method, we have derived a charge-shift corrected electronegativity scale for H, C, N, O, F, Cl, Li, and Na. Atomic charge shift character is defined using a similar approach resulting in values of 0.42, 1.06, 1.43, 1.62, 1.64, 1.44, 0.46, and 0.34 for H, C, N, O, F, Cl, Li, and Na, respectively. The charge-shift corrected electronegativity values presented herein follow the same general trends as Pauling's original values with the exception of Li having a smaller value than Na (1.57 and 1.91 for Li and Na respectively). The resonance energy is then broken down into components derived from the atomic charge shift character and polarization effects. It is then shown that most of the resonance energy in the charge-shift bonds H-F, H3C-F, and Li-CH3 and borderline charge-shift H-OH is associated with polarity rather than the intrinsic atomic charge-shift character of the bonding species. This suggests a rebranding of these bonds as "polar charge-shift" rather than simply "charge-shift". Lastly, using a similar breakdown method, it is shown that the small effect the substituents -CH3, -NH2, -OH, and -F have on the resonance energy (bonding atom.

  7. Prediction and measurement of the depletion interaction in charged colloidal systems and its effect on stability (United States)

    Sharma, Amber

    This dissertation was a study of the effect of introducing a nonadsorbing polyelectrolyte to a colloidal dispersion. Nonadsorbing macromolecular species in a colloidal dispersion result in what is termed the depletion effect. These macromolecules can be polymer molecules, micelles or other aggregates, or even other small particles. As two colloidal particles approach each other, such as through Brownian motion, the concentration of macromolecules in the gap region is altered relative to the bulk. At small separations, the macromolecules are excluded from the gap region, producing a depletion layer. This reduced concentration results in a lower osmotic pressure relative to the bulk and the resulting attraction is termed the depletion force. A force-balance model was developed to calculate the interaction force between two spherical particles in the presence of nonadsorbing spherical macromolecules. Both the higher order effects resulting from interactions between the macromolecules and, long range electrostatic repulsion for the macromolecule-macromolecule and particle-macromolecule interaction were included. The depletion interaction energy between a charged colloidal sphere and a charged flat plate in the presence of nonadsorbing silica macromolecules was measured using the optical technique of total internal reflection microscopy (TIRM). Comparisons of the measured energies to those predicted using a force-balance model indicated that the silica particles contribute slightly to the screening of the electrostatic interaction between the polystyrene particle and plate. Adjustment for this screening produces good agreement between theory and experiment. The effect of nonadsorbing silica on the stability of an electrically-stabilized dispersion of polystyrene latex was monitored using optical light scattering. Because of long range attractive depletion forces, reversible secondary flocculation of the particles occurred into a local potential energy minima. As has

  8. Antitumor effectiveness of different amounts of electrical charge in Ehrlich and fibrosarcoma Sa-37 tumors (United States)

    Ciria, HC; Quevedo, MS; Cabrales, LB; Bruzón, RP; Salas, MF; Pena, OG; González, TR; López, DS; Flores, JM


    Background In vivo studies were conducted to quantify the effectiveness of low-level direct electric current for different amounts of electrical charge and the survival rate in fibrosarcoma Sa-37 and Ehrlich tumors, also the effect of direct electric in Ehrlich tumor was evaluate through the measurements of tumor volume and the peritumoral and tumoral findings. Methods BALB/c male mice, 7–8 week old and 20–22 g weight were used. Ehrlich and fibrosarcoma Sa-37 cell lines, growing in BALB/c mice. Solid and subcutaneous Ehrlich and fibrosarcoma Sa-37 tumors, located dorsolaterally in animals, were initiated by the inoculation of 5 × 106 and 1 × 105 viable tumor cells, respectively. For each type of tumor four groups (one control group and three treated groups) consisting of 10 mice randomly divided were formed. When the tumors reached approximately 0.5 cm3, four platinum electrodes were inserted into their bases. The electric charge delivered to the tumors was varied in the range of 5.5 to 110 C/cm3 for a constant time of 45 minutes. An additional experiment was performed in BALB/c male mice bearing Ehrlich tumor to examine from a histolological point of view the effects of direct electric current. A control group and a treated group with 77 C/cm3 (27.0 C in 0.35 cm3) and 10 mA for 45 min were formed. In this experiment when the tumor volumes reached 0.35 cm3, two anodes and two cathodes were inserted into the base perpendicular to the tumor long axis. Results Significant tumor growth delay and survival rate were achieved after electrotherapy and both were dependent on direct electric current intensity, being more marked in fibrosarcoma Sa-37 tumor. Complete regressions for fibrosarcoma Sa-37 and Ehrlich tumors were observed for electrical charges of 80 and 92 C/cm3, respectively. Histopathological and peritumoral findings in Ehrlich tumor revealed in the treated group marked tumor necrosis, vascular congestion, peritumoral neutrophil infiltration, an acute

  9. Antitumor effectiveness of different amounts of electrical charge in Ehrlich and fibrosarcoma Sa-37 tumors

    Directory of Open Access Journals (Sweden)

    González TR


    Full Text Available Abstract Background In vivo studies were conducted to quantify the effectiveness of low-level direct electric current for different amounts of electrical charge and the survival rate in fibrosarcoma Sa-37 and Ehrlich tumors, also the effect of direct electric in Ehrlich tumor was evaluate through the measurements of tumor volume and the peritumoral and tumoral findings. Methods BALB/c male mice, 7–8 week old and 20–22 g weight were used. Ehrlich and fibrosarcoma Sa-37 cell lines, growing in BALB/c mice. Solid and subcutaneous Ehrlich and fibrosarcoma Sa-37 tumors, located dorsolaterally in animals, were initiated by the inoculation of 5 × 106 and 1 × 105 viable tumor cells, respectively. For each type of tumor four groups (one control group and three treated groups consisting of 10 mice randomly divided were formed. When the tumors reached approximately 0.5 cm3, four platinum electrodes were inserted into their bases. The electric charge delivered to the tumors was varied in the range of 5.5 to 110 C/cm3 for a constant time of 45 minutes. An additional experiment was performed in BALB/c male mice bearing Ehrlich tumor to examine from a histolological point of view the effects of direct electric current. A control group and a treated group with 77 C/cm3 (27.0 C in 0.35 cm3 and 10 mA for 45 min were formed. In this experiment when the tumor volumes reached 0.35 cm3, two anodes and two cathodes were inserted into the base perpendicular to the tumor long axis. Results Significant tumor growth delay and survival rate were achieved after electrotherapy and both were dependent on direct electric current intensity, being more marked in fibrosarcoma Sa-37 tumor. Complete regressions for fibrosarcoma Sa-37 and Ehrlich tumors were observed for electrical charges of 80 and 92 C/cm3, respectively. Histopathological and peritumoral findings in Ehrlich tumor revealed in the treated group marked tumor necrosis, vascular congestion, peritumoral neutrophil

  10. Effect of electrostatic charge in plastic spacers on the lung delivery of HFA-salbutamol in children

    DEFF Research Database (Denmark)

    Anhøj, J; Bisgaard, H; Lipworth, B J


    AIMS: The effect of the electrostatic charge in plastic spacers in vivo on drug delivery to the lung of hydrofluoroalkane (HFA) salbutamol spray was studied in children. METHODS: Five children, aged 7-12 years, were included in a 3-way crossover randomised single-blind trial. Salbutamol HFA spray...... delivered a significantly (Pcharge in plastic spacers reduces lung dose in children by more than two-fold. This is clinically significant and the use of potentially electrostatically charged...

  11. Effect of electrostatic charge in plastic spacers on the lung delivery of HFA-salbutamol in children

    DEFF Research Database (Denmark)

    Anhøj, J; Bisgaard, H; Lipworth, B J


    AIMS: The effect of the electrostatic charge in plastic spacers in vivo on drug delivery to the lung of hydrofluoroalkane (HFA) salbutamol spray was studied in children. METHODS: Five children, aged 7-12 years, were included in a 3-way crossover randomised single-blind trial. Salbutamol HFA spray...... delivered a significantly (Pchildren by more than two-fold. This is clinically significant and the use of potentially electrostatically charged...

  12. PARMELA-B A new version of PARMELA with coherent synchrotron radiation effects and a finite difference space charge routine

    CERN Document Server

    Koltenbah, B E C; Greegor, R B; Dowell, D H


    Recent interest in advanced laser light sources has stimulated development of accelerator systems of intermediate beam energy, 100-200 MeV, and high charge, 1-10 nC, for high power FEL applications and high energy, 1-2 GeV, high charge, SASE-FEL applications. The current generation of beam transport codes which were developed for high-energy, low-charge beams with low self-fields are inadequate to address this energy and charge regime, and better computational tools are required to accurately calculate self-fields. To that end, we have developed a new version of PARMELA, named PARMELA_B and written in Fortran 95, which includes a coherent synchrotron radiation (CSR) routine and an improved, generalized space charge (SC) routine. An electron bunch is simulated by a collection of macro-particles, which traverses a series of beam line elements. At each time step through the calculation, the momentum of each particle is updated due to the presence of external and self- fields. The self-fields are due to CSR and S...

  13. Electronic, structural and chemical effects of charge-transfer at organic/inorganic interfaces (United States)

    Otero, R.; Vázquez de Parga, A. L.; Gallego, J. M.


    reactivity of the adsorbates. The aim of this review is to start drawing general conclusions and developing new concepts which will help the scientific community to proceed more efficiently towards the understanding of organic/inorganic interfaces in the strong interaction limit, where charge-transfer effects must be taken into consideration.

  14. Effect of a cylindrical thin-shell of matter on the electrostatic self-force on a charge

    Energy Technology Data Exchange (ETDEWEB)

    Rubin de Celis, Emilio [Universidad de Buenos Aires y IFIBA, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina)


    The electrostatic self-force on a point charge in cylindrical thin-shell space-times is interpreted as the sum of a bulk field and a shell field. The bulk part corresponds to a field sourced by the test charge placed in a space-time without the shell. The shell field accounts for the discontinuity of the extrinsic curvature κ{sup p}{sub q}. An equivalent electric problem is stated, in which the effect of the shell of matter on the field is reconstructed with the electric potential produced by a non-gravitating charge distribution of total image charge Q, to interpret the shell field in both the interior and exterior regions of the space-time. The self-force on a point charge q in a locally flat geometry with a cylindrical thin-shell of matter is calculated. The charge is repelled from the shell if κ{sup p}{sub q} = κ < 0 (ordinarymatter) and attracted toward the shell if κ > 0 (exotic matter). The total image charge is zero for exterior problems, while for interior problems Q/q = κr{sub e}, with re the external radius of the shell. The procedure is general and can be applied to interpret self-forces in other space-times with shells, e.g., for locally flat wormholes we found Q{sub -+}{sup wh}/q = -1/(κ{sub wh}r{sub ±}). (orig.)

  15. Image analysis of single event transient effects on charge coupled devices irradiated by protons

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zujun, E-mail: [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O. Box 69-10, Xi’an (China); Xue, Yuanyuan [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O. Box 69-10, Xi’an (China); Liu, Jing [School of Materials Science and Engineering, Xiangtan University, Hunan (China); He, Baoping; Yao, Zhibin; Ma, Wuying [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O. Box 69-10, Xi’an (China)


    The experiments of single event transient (SET) effects on charge coupled devices (CCDs) irradiated by protons are presented. The radiation experiments have been carried out at the accelerator protons with the energy of 200 MeV and 60 MeV.The incident angles of the protons are at 30°and 90° to the plane of the CCDs to obtain the images induced by the perpendicularity and incline incident angles. The experimental results show that the typical characteristics of the SET effects on a CCD induced by protons are the generation of a large number of dark signal spikes (hot pixels) which are randomly distributed in the “pepper” images. The characteristics of SET effects are investigated by observing the same imaging area at different time during proton radiation to verify the transient effects. The experiment results also show that the number of dark signal spikes increases with increasing integration time during proton radiation. The CCDs were tested at on-line and off-line to distinguish the radiation damage induced by the SET effects or DD effects. The mechanisms of the dark signal spike generation induced by the SET effects and the DD effects are demonstrated respectively.

  16. Non-stationary Effects In Space-charge Dominated Electron Beams

    CERN Document Server

    Agafonov, A V; Tarakanov, V P


    Problems of non-linear dynamics of space charge dominated electron beams in plane and in coaxial electron guns are discussed from the point of view of non-stationary behaviour of beams. The results of computer simulations of beam formation are presented for several simple plane diode geometries and for the gun with large compression of annular beam. Emphasised is non-stationary behaviour combined with edge and hysteresis effects. Non-stationary effects in crossed electron and magnetic field are considered from the point of view a development of schemes of intense electron beam formation for compact accelerators and RF-devices. The results of computer simulation of beam formation inside coaxial guns are described under condition of secondary self-sustaining emission. Possibilities of electron storage and capture due to transient processes are discussed. Work supported by RFBR under grant 03-02-17301.

  17. Antiproton-proton annihilation into charged light meson pairs within effective meson theory (United States)

    Wang, Ying; Bystritskiy, Yury M.; Tomasi-Gustafsson, Egle


    We revisit antiproton-proton annihilation into light mesons in the energy domain relevant to the antiproton annihilation at Darmstadt (PANDA) experiment at the GSI Facility for Antiproton and Ion Research (FAIR) [2.25 (1.5 ) ≤√{s }(pL) ≤5.47 (15 ) GeV (GeV /c ) where √{s }(pL) is the total energy (the beam momentum in the laboratory frame)]. An effective meson model is developed, with mesonic and baryonic degrees of freedom. Form factors are added to take into account the composite nature of the interacting hadrons. A comparison is made with the existing data for charged pion pair production and predictions for angular distributions and energy dependence in the range 3.362 (5 ) ≤√{s }(pL) ≤4.559 (10.1 ) GeV (GeV /c ). The model is applied to π±p elastic scattering, using crossing symmetry, and to charged kaon pair production, on the basis of SU(3) symmetry. In all cases the results illustrate a nice agreement with the data.

  18. Hall-effect based semi-fast AC on-board charging equipment for electric vehicles. (United States)

    Milanés-Montero, María Isabel; Gallardo-Lozano, Javier; Romero-Cadaval, Enrique; González-Romera, Eva


    The expected increase in the penetration of electric vehicles (EV) and plug-in hybrid electric vehicles (PHEV) will produce unbalanced conditions, reactive power consumption and current harmonics drawn by the battery charging equipment, causing a great impact on the power quality of the future smart grid. A single-phase semi-fast electric vehicle battery charger is proposed in this paper. This ac on-board charging equipment can operate in grid-to-vehicle (G2V) mode, and also in vehicle-to-grid (V2G) mode, transferring the battery energy to the grid when the vehicle is parked. The charger is controlled with a Perfect Harmonic Cancellation (PHC) strategy, contributing to improve the grid power quality, since the current demanded or injected has no harmonic content and a high power factor. Hall-effect current and voltage transducers have been used in the sensor stage to carry out this control strategy. Experimental results with a laboratory prototype are presented.


    Directory of Open Access Journals (Sweden)

    Mary Trujillo


    Full Text Available Solubility, structure and position of charges in a peptide antigen sequence can be mentioned as being amongst the basic features of adsorption. In order to study their effect on adsorption, seven analogue series were synthesized from a MSP-1 peptide sequence by systematically replacing each one of the positions in the peptide sequence by aspartic acid, glutamic acid, serine, alanine, asparagine, glutamine or lysine. Such modifications in analogue peptide sequences showed a non-regular tendency regarding solubility and adsorption data. Aspartic acid and Glutamic acid analogue series showed great improvements in adsorption, especially in peptides where Lysine in position 6 and Arginine in position 13 were replaced. Solubility of position 5 analogue was greater than the position 6 analogue in Aspartic acid series; however, the position 6 analogue showed best adsorption results whilst the Aspartic acid in position 5 analogue showed no adsorption in the same conditions. Nuclear Magnetic Resonance structural analysis revealed differences in the -helical structureextension between these analogues. The Aspartic acid in position 6, located in the polar side of the helix, may allow this analogueto fit better onto the adsorption regions suggesting that the local electrostatic charge is responsible for this behavior.

  20. Direct space-charge effects on the ILC damping rings: Task ForceReport

    Energy Technology Data Exchange (ETDEWEB)

    Venturini, Marco; Oide, Katsunobu


    In 2005 a global effort was initiated to conduct studies for a baseline recommendation for the various components of the International Linear Collider (ILC). Work for the damping rings was subdivided in a number of tasks. This Report contains the contribution to this effort by the Authors as Coordinators of the Task Force on space charge. (A slightly reduced version of this document can also be found as part of the ''Configuration Studies and Recommendations for the ILC Damping Rings'', Edts. A. Wolski, et al., LBNL-59449.) The studies documented in this Report were carried out for several of the reference lattices considered for the baseline recommendation. Space charge effects were found to be quite noticeable in the lattices with the longest circumference. Although it does not appear that they could prevent operation of any machine having such lattices they do favor a choice of a ring design with shorter ({approx}6km) circumference at 5 GeV.

  1. Primary Phenomenon in the Network Formation of Endothelial Cells: Effect of Charge. (United States)

    Arai, Shunto


    Blood vessels are essential organs that are involved in the supply of nutrients and oxygen and play an important role in regulating the body's internal environment, including pH, body temperature, and water homeostasis. Many studies have examined the formation of networks of endothelial cells. The results of these studies have revealed that vascular endothelial growth factor (VEGF) affects the interactions of these cells and modulates the network structure. Though almost all previous simulation studies have assumed that the chemoattractant VEGF is present before network formation, vascular endothelial cells secrete VEGF only after the cells bind to the substrate. This suggests VEGF is not essential for vasculogenesis especially at the early stage. Using a simple experiment, we find chain-like structures which last quite longer than it is expected, unless the energetically stable cluster should be compact. Using a purely physical model and simulation, we find that the hydrodynamic interaction retard the compaction of clusters and that the chains are stabilized through the effects of charge. The charge at the surface of the cells affect the interparticle potential, and the resulting repulsive forces prevent the chains from folding. The ions surrounding the cells may also be involved in this process.

  2. Primary Phenomenon in the Network Formation of Endothelial Cells: Effect of Charge

    Directory of Open Access Journals (Sweden)

    Shunto Arai


    Full Text Available Blood vessels are essential organs that are involved in the supply of nutrients and oxygen and play an important role in regulating the body’s internal environment, including pH, body temperature, and water homeostasis. Many studies have examined the formation of networks of endothelial cells. The results of these studies have revealed that vascular endothelial growth factor (VEGF affects the interactions of these cells and modulates the network structure. Though almost all previous simulation studies have assumed that the chemoattractant VEGF is present before network formation, vascular endothelial cells secrete VEGF only after the cells bind to the substrate. This suggests VEGF is not essential for vasculogenesis especially at the early stage. Using a simple experiment, we find chain-like structures which last quite longer than it is expected, unless the energetically stable cluster should be compact. Using a purely physical model and simulation, we find that the hydrodynamic interaction retard the compaction of clusters and that the chains are stabilized through the effects of charge. The charge at the surface of the cells affect the interparticle potential, and the resulting repulsive forces prevent the chains from folding. The ions surrounding the cells may also be involved in this process.

  3. Hall-Effect Based Semi-Fast AC On-Board Charging Equipment for Electric Vehicles (United States)

    Milanés-Montero, María Isabel; Gallardo-Lozano, Javier; Romero-Cadaval, Enrique; González-Romera, Eva


    The expected increase in the penetration of electric vehicles (EV) and plug-in hybrid electric vehicles (PHEV) will produce unbalanced conditions, reactive power consumption and current harmonics drawn by the battery charging equipment, causing a great impact on the power quality of the future smart grid. A single-phase semi-fast electric vehicle battery charger is proposed in this paper. This ac on-board charging equipment can operate in grid-to-vehicle (G2V) mode, and also in vehicle-to-grid (V2G) mode, transferring the battery energy to the grid when the vehicle is parked. The charger is controlled with a Perfect Harmonic Cancellation (PHC) strategy, contributing to improve the grid power quality, since the current demanded or injected has no harmonic content and a high power factor. Hall-effect current and voltage transducers have been used in the sensor stage to carry out this control strategy. Experimental results with a laboratory prototype are presented. PMID:22163697

  4. On the effect of neglecting anharmonic nuclear motion in charge density studies. (United States)

    Meindl, Kathrin; Herbst-Irmer, Regine; Henn, Julian


    The effect of neglecting anharmonic nuclear motion when it is definitely present is studied. To ensure the presence of anharmonic nuclear motion a model was used that was previously refined against experimental data including anharmonic nuclear motion, and these calculated structure factors were used as observed data for a multipole refinement. It was then studied how the neglect of anharmonic nuclear motion and noise in the data affects the usual crystallographic quality measure R, the density parameters and the residual density distribution. It is demonstrated that the neglect of anharmonic nuclear motion leads to a characteristic imprint onto the residual density distribution in terms of residual density peaks and holes, in terms of the whole residual density distribution and in terms of the number, location and strength of valence shell charge concentrations (VSCCs). These VSCCs differ from that of the input model in a way which heavily influences and misleads the chemical interpretation of the charge density. This imprint vanishes after taking anharmonic nuclear motion into account. Also the input model VSCCs are restored. The importance of modeling anharmonic nuclear motion is furthermore shown by the characteristic imprint on the residual density distribution, even in the case of a numerically almost unaffected R value.

  5. Experimental study on the effect of alternator speed to the car charging system

    Directory of Open Access Journals (Sweden)

    Mazlan Rozdman K.


    Full Text Available In this paper, we present our work, which is doing an energy audit on alternator’s current output and battery’s voltage based on alternator speed. Up until today, the demand for power in automobile is ever increasing. As technology advances, more and more electrical devices were produced and being installed in vehicles. To cope with the demand, alternator has been designed and modified so that it can produce enough power. This research is to study the effect of alternator speed to the charging system. The car used in this experiment is Proton Preve 1.6 Manual. In both ISO 8854 and SAE J 56, alternator testing and labelling standards indicate that the rated output an alternator is the amount of current that it is capable of producing at 6,000 RPM. Three different constant speed of engine which is 750 RPM as idle speed, 1500 RPM and 3000 RPM as cruise speed were taken as parameter. The speed of the alternator was measured using tachometer, digital multi-meter was used to measure battery’s voltage, and AC/DC Clamp was used to measure alternator current output. The result shows that the faster the alternator spin, the more power it can produce. And when there is more power, the faster the charging rate of the battery.

  6. Simulations of charge summing and threshold dispersion effects in Medipix3

    CERN Document Server

    Pennicard, D; Llopart, X; Graafsma, H; Campbell, M


    A novel feature of the Medipix3 photon-counting pixel readout chip is inter-pixel communication. By summing together the signals from neighbouring pixels at a series of ``summing nodes{''}, and assigning each hit to the node with the highest signal, the chip can compensate for charge-sharing effects. However, previous experimental tests have demonstrated that the node-to-node variation in the detector's response is very large. Using computer simulations, it is shown that this variation is due to threshold dispersion, which results in many hits being assigned to whichever summing node in the vicinity has the lowest threshold level. A reduction in threshold variation would attenuate but not solve this issue. A new charge summing and hit assignment process is proposed, where the signals in individual pixels are used to determine the hit location, and then signals from neighbouring pixels are summed to determine whether the total photon energy is above threshold. In simulation, this new mode accurately assigns ea...

  7. Effective charges of ionic liquid determined self-consistently through combination of molecular dynamics simulation and density-functional theory. (United States)

    Ishizuka, Ryosuke; Matubayasi, Nobuyuki


    A self-consistent scheme combining the molecular dynamics (MD) simulation and density functional theory (DFT) was recently proposed to incorporate the effects of the charge transfer and polarization of ions into non-poralizable force fields of ionic liquids for improved description of energetics and dynamics. The purpose of the present work is to analyze the detailed setups of the MD/DFT scheme by focusing on how the basis set, exchange-correlation (XC) functional, charge-fitting method or force field for the intramolecular and Lennard-Jones interactions affects the MD/DFT results of 1,3-dimethylimidazolium bis(trifluoromethylsulfonyl) imide ( [C1mim][NTf2]) and 1-ethyl-3-methylimidazolium glycinate ( [C2mim][Gly]). It was found that the double-zeta valence polarized or larger size of basis set is required for the convergence of the effective charge of the ion. The choice of the XC functional was further not influential as far as the generalized gradient approximation is used. The charge-fitting method and force field govern the accuracy of the MD/DFT scheme, on the other hand. We examined the charge-fitting methods of Blöchl, the iterative Hirshfeld (Hirshfeld-I), and REPEAT in combination with Lopes et al.'s force field and general AMBER force field. There is no single combination of charge fitting and force field that provides good agreements with the experiments, while the MD/DFT scheme reduces the effective charges of the ions and leads to better description of energetics and dynamics compared to the original force field with unit charges. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  8. Method and tool to reverse the charges in anti-reflection films used for solar cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Vivek; Tracy, Clarence


    A method is provided for making a solar cell. The method includes providing a stack including a substrate, a barrier layer disposed on the substrate, and an anti-reflective layer disposed on the barrier layer, where the anti-reflective layer has charge centers. The method also includes generating a corona with a charging tool and contacting the anti-reflective layer with the corona thereby injecting charge into at least some of the charge centers in the anti-reflective layer. Ultra-violet illumination and temperature-based annealing may be used to modify the charge of the anti-reflective layer.

  9. Disorder Effects in Charge Transport and Spin Response of Topological Insulators (United States)

    Zhao, Lukas Zhonghua

    Topological insulators are a class of solids in which the non-trivial inverted bulk band structure gives rise to metallic surface states that are robust against impurity backscattering. First principle calculations predicted Bi2Te3, Sb2Te3 and Bi2Se3 to be three-dimensional (3D) topological insulators with a single Dirac cone on the surface. The topological surface states were subsequently observed by angle-resolved photoemission (ARPES) and scanning tunneling microscopy (STM). The investigations of charge transport through topological surfaces of 3D topological insulators, however, have faced a major challenge due to large charge carrier densities in the bulk donated by randomly distributed defects such as vacancies and antisites. This bulk disorder intermixes surface and bulk conduction channels, thereby complicating access to the low-energy (Dirac point) charge transport or magnetic response and resulting in the relatively low measured carrier mobilities. Moreover, charge inhomogeneity arising from bulk disorder can result in pronounced nanoscale spatial fluctuations of energy on the surface, leading to the formation of surface `puddles' of different carrier types. Great efforts have been made to combat the undesirable effects of disorder in 3D topological insulators and to reduce bulk carriers through chemical doping, nanostructure fabrication, and electric gating. In this work we have developed a new way to reduce bulk carrier densities using high-energy electron irradiation, thereby allowing us access to the topological surface quantum channels. We also found that disorder in 3D topological insulators can be beneficial. It can play an important part in enabling detection of unusual magnetic response from Dirac fermions and in uncovering new excitations, namely surface superconductivity in Dirac `puddles'. In Chapter 3 we show how by using differential magnetometry we could probe spin rotation in the 3D topological material family (Bi2Se 3, Bi2Te3 and Sb2Te3

  10. Charge Recombination, Transport Dynamics, and Interfacial Effects in Organic Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Heeger, Alan [Univ. of California, Santa Barbara, CA (United States); Bazan, Guillermo [Univ. of California, Santa Barbara, CA (United States); Nguyen, Thuc-Quyen [Univ. of California, Santa Barbara, CA (United States); Wudl, Fred [Univ. of California, Santa Barbara, CA (United States)


    The need for renewable sources of energy is well known. Conversion of sunlight to electricity using solar cells is one of the most important opportunities for creating renewable energy sources. The research carried out under DE-FG02-08ER46535 focused on the science and technology of “Plastic” solar cells comprised of organic (i.e. carbon based) semiconductors. The Bulk Heterojunction concept involves a phase separated blend of two organic semiconductors each with dimensions in the nano-meter length scale --- one a material that functions as a donor for electrons and the other a material that functions as an acceptor for electrons. The nano-scale inter-penetrating network concept for “Plastic” solar cells was created at UC Santa Barbara. A simple measure of the impact of this concept can be obtained from a Google search which gives 244,000 “hits” for the Bulk Heterojunction solar cell. Research funded through this program focused on four major areas: 1. Interfacial effects in organic photovoltaics, 2. Charge transfer and photogeneration of mobile charge carriers in organic photovoltaics, 3. Transport and recombination of the photogenerated charge carriers in organic photovoltaics, 4. Synthesis of novel organic semiconducting polymers and semiconducting small molecules, including conjugated polyelectrolytes. Following the discovery of ultrafast charge transfer at UC Santa Barbara in 1992, the nano-organic (Bulk Heterojunction) concept was formulated. The need for a morphology comprising two interpenetrating bicontinuous networks was clear: one network to carry the photogenerated electrons (negative charge) to the cathode and one network to carry the photo-generated holes (positive charge) to the anode. This remarkable self-assembled network morphology has now been established using Transmission electron Microscopy (TEM) either in the Phase Contrast mode or via TEM-Tomography. The steps involved in delivering power from a solar cell to an external circuit

  11. Effect of paraelectrode processes on contraction of space charge in periodic-pulse lasers (United States)

    Arytyunyan, R. V.; Baranov, V. Yu.; Borisov, V. M.; Vinokhodov, A. Yu.; Kiryukhin, Yu. B.


    A characteristic feature of periodic-pulse electric-discharge CO2-lasers and excimer lasers is contraction of the space charge as the pulse repetition rate increases. The emission energy per pulse decreases as a consequence, with the average laser power first ceasing to increase linearly beyond a certain corner repetition rate and then decreasing beyond a certain critical repetition rate. A study of this phenomenon was made, for the purpose of separating the effect of paracathode processes from the effect of gas dynamics and then evaluating the effect of the former alone. Paraelectrode perturbations were simulated by focusing the radiation from the an XeCl-laser on the cathode surface in an atmosphere of nonabsorbing gases. Laser pulses of up to approximately 0.5 J energy and of approximately 50 ns duration were focused within a spot of 1 mm(2) area on a cathode inside a discharge chamber, with the power density of incident radiation regulated by means of an attenuator. A space charge within a volume of 2.5x4.5x9 cm(3) was generated between this specially shaped cathode and a mesh anode with an approximately 50% optical transmission coefficient. The space charge in helium and in neon was photographed, and the time lag of a discharge pulse behind a contracting laser pulse was measured as a function of the laser pulse energy for these two gases, as well as for a He+C12 gas mixture. The general trend was found to be the same in each case, the time lag increasing with increasing energy first at a slower rate up to a critical energy level and then faster. It has been established that plasma does not build up on the cathode before the laser pulse energy reaches 30 mJ (for a 3 mm(2) surface area), while plasma glow begins as the laser pulse energy reaches 150 mJ. A contracted channel begins to form within the laser-cathode interaction space, with an attendant fast increase of the time lag owing to evaporation of the cathode metal.

  12. Long-lived photoinduced charge separation for solar cell applications in supramolecular complexes of multi-metalloporphyrins and fullerenes. (United States)

    Fukuzumi, Shunichi; Ohkubo, Kei


    Monomers, dimers, trimers, dendrimers and oligomers of metalloporphyrins form supramolecular complexes with fullerene derivatives via electrostatic interactions, π-π interactions and coordination bonds. Photoexcitation of the supramolecular complexes resulted in photoinduced electron transfer from the porphyrin moiety to the fullerene moiety to produce the charge-separated states as revealed by laser flash photolysis measurements. The rate constants of photoinduced charge separation and charge recombination in supramolecular complexes of multi-metalloporphyrins and fullerenes were also determined by laser flash photolysis measurements and the results depending on the number of porphyrins in the supramolecular complexes are discussed in terms of efficiency of photoinduced energy transfer and charge separation as well as the lifetimes of charge-separated states. The photoelectrochemical performances of solar cells composed of supramolecular complexes of monomers, dimers, dendrimers and oligomers of metalloporphyrins with fullerenes are compared in relation to the rate constants of photoinduced charge separation and charge recombination.

  13. Investigations of charge state effects in non-specific transition metal-protein complexes by ESI-FTICR

    Energy Technology Data Exchange (ETDEWEB)

    Van Orden, S.L.; Bakhtiar, R.; Bruce, J.E.; Hofstadler, S.A.; Smith, R.D. [Pacific Northwest Labs., Richland, WA (United States)


    Transition metals play an important role in many areas of biological chemistry. Various aspects of the interactions of transition metal ions and complexes with protein have been studied by a number of groups. In general, these studies have concentrated on proteins which specifically bind metals (e.g. zinc finger motifs) and have not investigated metal ion charge state. It is well known that the electrospray ionization of solutions containing proteins and transition metal salts produces protein molecular ions and protein ions which are multiply adducted with the metal. For the multiply adducted ions, the origin of the charge may be questioned. Presumably the overall charge of the ion is due to H{sup +} attachment, because little or no shift in the charge state distribution is observed between the apo and metalated forms of the protein. In such a case the metal ion is effectively neutralized through multiple bonds to the protein by H{sup +} displacement.

  14. Optical and electrochemical methods for determining the effective area and charge density of conducting polymer modified electrodes for neural stimulation. (United States)

    Harris, Alexander R; Molino, Paul J; Kapsa, Robert M I; Clark, Graeme M; Paolini, Antonio G; Wallace, Gordon G


    Neural stimulation is used in the cochlear implant, bionic eye, and deep brain stimulation, which involves implantation of an array of electrodes into a patient's brain. The current passed through the electrodes is used to provide sensory queues or reduce symptoms associated with movement disorders and increasingly for psychological and pain therapies. Poor control of electrode properties can lead to suboptimal performance; however, there are currently no standard methods to assess them, including the electrode area and charge density. Here we demonstrate optical and electrochemical methods for measuring these electrode properties and show the charge density is dependent on electrode geometry. This technique highlights that materials can have widely different charge densities but also large variation in performance. Measurement of charge density from an electroactive area may result in new materials and electrode geometries that improve patient outcomes and reduce side effects.

  15. Determination of effective charges and ionic mobilities of polycationic antimicrobial peptides by capillary isotachophoresis and capillary zone electrophoresis. (United States)

    Tůmová, Tereza; Monincová, Lenka; Nešuta, Ondřej; Čeřovský, Václav; Kašička, Václav


    Capillary ITP (CITP) and CZE were applied to the determination of effective charges and ionic mobilities of polycationic antimicrobial peptides (AMPs). Twelve AMPs (deca- to hexadecapeptides) containing three to seven basic amino acid residues (His, Lys, Arg) at variable positions of peptide chain were investigated. Effective charges of the AMPs were determined from the lengths of their ITP zones, ionic mobilities, and molar concentrations, and from the same parameters of the reference compounds. Lengths of the ITP zones of AMPs and reference compounds were obtained from their CITP analyses in cationic mode using leading electrolyte (LE) composed of 10 mM NH4 OH, 40 mM AcOH (acetic acid), pH 4.1, and terminating electrolyte (TE) containing 40 mM AcOH, pH 3.2. Ionic mobilities of AMPs and singly charged reference compounds (ammediol or arginine) were determined by their CZE analyses in the BGE of the same composition as the LE. The effective charges numbers of AMPs were found to be in the range 1.65-5.04, i.e. significantly reduced as compared to the theoretical charge numbers (2.86-6.99) calculated from the acidity constants of the analyzed AMPs. This reduction of effective charge due to tightly bound acetate counterions (counterion condensation) was in the range 17-47% depending on the number and type of the basic amino acid residues in the AMPs molecules. Ionic mobilities of AMPs achieved values (26.5-38.6) × 10(-9)  m(2) V(-1) s(-1) and in most cases were in a good agreement with the ratio of their effective charges and relative molecular masses. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Trapping a Charged Atom

    Energy Technology Data Exchange (ETDEWEB)

    Hla, Saw-Wai [Center for Nanoscale Materials, Nanoscience and Technology Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Nanoscience and Quantum Phenomena Institute and Condensed Matter and Surface Science Program, Ohio University, Athens, Ohio 45701, United States


    Engineering of supramolecular assemblies on surfaces is an emerging field of research impacting chemistry, electronics, and biology. Among supramolecular assemblies, metal-containing structures provide rich properties and enable robust nanostructured designs. In this issue of ACS Nano, Feng eta!, report that supramolecular assemblies can trap gold adatoms that maintain a charged state on a Au(111) surface. Such charged adatoms may offer additional degrees of freedom in designing novel supramolecular architectures for efficient catalysts, memory, and charge storage for medical applications.

  17. Space Charge effects and mitigation in the CERN PS Booster, in view of the Upgrade

    CERN Document Server

    AUTHOR|(CDS)2068441; Cieslak-Kowalska, Magdalena Anna; Forte, Vincenzo; Schmidt, Frank


    The CERN PS Booster (PSB) is presently running with a space charge tune spread larger than 0.5 at injection. Since the High Luminosity LHC (HL-LHC) will require beams with twice the intensity and brightness of today, the LHC Injector Upgrade (LIU) Project is putting in place an upgrade program for all the injector chain and, in particular, it relies on the important assumption that the PS Booster can successfully produce these beams after the implementation of the 160 MeV H- injection from Linac4. This contribution describes the studies (measure-ments and simulations) that have been carried out to con- firm that the PSB can indeed perform as needed in terms of beam brightness for the future HL-LHC runs. The importance of the mitigation measures already in place, such as the correction of the half-integer line, and the effects of non-linear resonances on the beam are also discussed.

  18. Anisotropic pressure effects on the charge order transition of (TMTTF){sub 2}X

    Energy Technology Data Exchange (ETDEWEB)

    Nagasawa, M., E-mail: [Department of Physics, Tokyo Denki University (Japan); Department of Green and Sustainable Chemistry, Tokyo Denki University (Japan); Nagasawa, T. [Department of Green and Sustainable Chemistry, Tokyo Denki University (Japan); Ichimura, K. [Division of Applied Physics, Hokkaido University (Japan); Nomura, K. [Division of Physics, Hokkaido University (Japan)


    We measured the conductivity along the a-direction {sigma}{sub a}(T) of the quasi one-dimensional organic conductor (TMTTF){sub 2}SbF{sub 6} under several anisotropic pressures of uniaxial strains which are parallel and perpendicular to the a-direction. The uniaxial strains were generated by so-called 'Frozen oil method'. It was found that the tendencies of the uniaxial strain dependence of the conductivity and the charge order (CO) transition temperature T{sub CO} are different. According to T{sub CO}, it decreases strongly with increasing uniaxial strain parallel to the a-direction; however, it is almost constant for that perpendicular to the a-direction. We discuss the effects of compressive uniaxial strains on the conductivity and the CO transition of (TMTTF){sub 2}SbF{sub 6}.

  19. Electrokinetics of charged spherical colloidal particles taking into account the effect of ion size constraints. (United States)

    López-García, J J; Aranda-Rascón, M J; Grosse, C; Horno, J


    The electrokinetic properties of suspended spherical particles are examined using a modified standard electrokinetic model, which takes into account the finite ion size and considers that the minimum approach distance of ions to the particle surface need not be equal to their effective radius in the bulk solution. We calculate the conductivity increment and the electrophoretic mobility and present a detailed interpretation of the obtained results, based on the analysis of the equilibrium and field-induced ion concentrations, as well as the convective fluid flow in the neighborhood of the particle surface. We show that when charge reversal takes place, the sign of the concentration polarization remains unchanged while the sign of the electrophoretic mobility only changes under favorable circumstances. Copyright © 2010 Elsevier Inc. All rights reserved.

  20. Systematic studies on the effect of linear lattice optics for space-charge limited beams

    CERN Document Server

    Fitterer, M; Molodozhentsev, A; Müller, A S


    The HL-LHC (High Luminosity LHC) project aims to an increase of the luminosity of the LHC by a factor of 10. In order to realize this ambitious goal, the LHC itself has to undergo a major upgrade accompanied by an extensive upgrade of the complete injector complex referred to as LHC injector upgrade (LIU). In the framework of the LIU project, a new rapid cycling synchrotron (RCS) as an alternative to the energy upgrade of the existing PS Booster has been proposed. Motivated by the optics studies conducted for this RCS, the more general question of the influence of the linear optics on the machine performance has been raised. In this paper, we want to investigate this question by comparing different lattices with the final aim of identifying lattice characteristics advantageous under strong space-charge effects.

  1. Pre-equilibrium effects in charge-asymmetric low-energy reactions

    Directory of Open Access Journals (Sweden)

    H. Zheng


    Full Text Available We study the pre-equilibrium dipole response in the charge-asymmetric reaction Sn132+Ni58 at Elab=10 MeV/A, within a semi-classical transport model employing effective interactions for the nuclear mean-field. In particular, we adopt the recently introduced SAMi-J Skyrme interactions, whose parameters are specifically tuned to improve the description of spin–isospin properties of nuclei. Within the same framework, we also discuss pre-equilibrium nucleon emission. Our results show that both mechanisms, i.e., pre-equilibrium dipole oscillations and nucleon emission, are sensitive to the symmetry energy below the saturation density ρ0 (in the range 0.6ρ0−ρ0, to the momentum dependence of the mean-field potential and to the nucleon–nucleon cross section. Finally, a correlation analysis is applied to examine the impact of the model parameters on observables of experimental interest.

  2. Space Environments and Effects (SEE) Program: Spacecraft Charging Technology Development Activities (United States)

    Kauffman, B.; Hardage, D.; Minor, J.


    Reducing size and weight of spacecraft, along with demanding increased performance capabilities, introduces many uncertainties in the engineering design community on how materials and spacecraft systems will perform in space. The engineering design community is forever behind on obtaining and developing new tools and guidelines to mitigate the harmful effects of the space environment. Adding to this complexity is the continued push to use Commercial-off-the-Shelf (COTS) microelectronics, potential usage of unproven technologies such as large solar sail structures and nuclear electric propulsion. In order to drive down these uncertainties, various programs are working together to avoid duplication, save what resources are available in this technical area and possess a focused agenda to insert these new developments into future mission designs. This paper will introduce the SEE Program, briefly discuss past and currently sponsored spacecraft charging activities and possible future endeavors.

  3. Modulation of charge transport properties in poly(3,4-ethylenedioxythiophene) nanocomposites for thermoelectric applications (United States)

    Galliani, Daniela; Battiston, Simone; Ruffo, Riccardo; Trabattoni, Silvia; Narducci, Dario


    Conjugated polymer poly(3,4-dioxyethylenthiofene) (PEDOT) has recently gained attention for room-temperature thermoelectric applications due to its low cost, safety and the possibility of easy processing. This makes it an interesting prospective alternative to tellurides commonly used around room temperature. Still, low thermoelectric efficiencies of polymers might be more easily increased, were a model of its transport properties available. The aim of this paper is to validate a model recently reported, making use of the concept of transport energy to frame the onset of transport properties reported over the last few years in the literature. To this aim, PEDOT and PEDOT-based nanocomposites embedding CuO nanoplatelets were prepared and analysed. We found that the model adequately fits the trends observed in pure PEDOT and in its nanocomposites. Transport and Fermi energy were verified to depend on the polymer oxidation level only,while the transport coefficient was found to be sensitive to PEDOT stacking and was modulated by the introduction of CuO nanoplatelets.

  4. Synergistic effects of negatively charged hydrophobic nanoparticles and (-)-epigallocatechin-3-gallate on inhibiting amyloid β-protein aggregation. (United States)

    Liu, Hongchen; Yu, Linling; Dong, Xiaoyan; Sun, Yan


    Fibrillogenesis of amyloid β-protein (Aβ) in human brain has been implicated as the main cause of Alzheimer's disease. A few small molecules from natural sources have been discovered for their inhibition effects on Aβ fibrillation, of which (-)-epigallocatechin-3-gallate (EGCG) is one of the most broadly investigated compounds for its potent inhibitory activity. However, in vivo applicability of the inhibitors is largely limited by their low transmembrane efficiency. Hence, it is of great significance to develop inhibition systems that function at low concentrations. In this work, a dual-inhibitor system containing EGCG and negatively charged polymeric nanoparticles (NP10), which was also demonstrated effective on the inhibition of Aβ aggregation, was developed and comprehensively studied by extensive biophysical and biological assays. It was found that the dual-inhibitor system at low concentrations was more effective on the inhibition and detoxification of Aβ (Aβ42 and Aβ40) fibrillation than the additive effects of these two agents working individually. Namely, there was a synergistic effect of the two inhibitors. The synergism factor reached 1.25 with 5μM EGCG and 5μg/mL NP10. Kinetic studies with Aβ40 revealed that the two inhibitors functioned in different Aβ assembling stages: NP10 mainly inhibited primary nucleation, while EGCG suppressed fibril elongation and changed the fibril structure to make it show less seeding activities in the secondary nucleation. NP10 might also help EGCG binding to Aβ, leading to its enhanced inhibitory effects on fibril elongation and secondary nucleation. The synergistic effect observed in the dual-inhibitor system offered new insight into the development of potent inhibitor systems against amyloid neurotoxicity. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Effect of bridge on energy transfer and photoinduced charge separation in perylene-diimide-naphthalene-bisimide-hexathiophene based donor-bridge-acceptor triads

    Directory of Open Access Journals (Sweden)

    Tilley T.D.


    Full Text Available Femtosecond transient absorption spectroscopy is performed to assess bridge effects on energy transfer and charge separation in molecular junctions. A short, conjugated bridge can facilitate charge separation from both donor and acceptor, whereas in longer bridges charge separation only occurs from the excited donor.

  6. Effect of surface charge distribution on the crystal growth of sodium perborate tetrahydrate (United States)

    Sahın, Ömer; Nusret Bulutcu, A.


    Growth and dissolution rates of sodium perborate crystals have been measured in a flow-type single-crystal cell. Sodium perborate grows dendritically at any level of supersaturation and shows growth and dissolution rate dispersion. Both the growth and dissolution rates of sodium perborate were found to be controlled by surface charge distribution which is represented by applied voltages in an electrostatic separator. It was determined that high surface charge dominates the crystal growth rate when compared with low surface charge under identical conditions. The results obtained showed that the formation of dendritic structure is not a function of supersaturation but a function of surface charge. The rate of dissolution of a crystal with a high surface charge is greater than that with a low surface charge.

  7. Parallel Control over Surface Charge and Wettability Using Polyelectrolyte Architecture: Effect on Protein Adsorption and Cell Adhesion. (United States)

    Guo, Shanshan; Zhu, Xiaoying; Li, Min; Shi, Liya; Ong, June Lay Ting; Jańczewski, Dominik; Neoh, Koon Gee


    Surface charge and wettability, the two prominent physical factors governing protein adsorption and cell adhesion, have been extensively investigated in the literature. However, a comparison between these driving forces in terms of their independent and cooperative effects in affecting adhesion is rarely explored on a systematic and quantitative level. Herein, we formulate a protocol that features two-dimensional control over both surface charge and wettability with limited cross-parameter influence. This strategy is implemented by controlling both the polyion charge density in the layer-by-layer (LbL) assembly process and the polyion side-chain chemical structures. The 2D property matrix spans surface isoelectric points ranging from 5 to 9 and water contact angles from 35 to 70°, with other interferential factors (e.g., roughness) eliminated. The interplay between these two surface variables influences protein (bovine serum albumin, lysozyme) adsorption and 3T3 fibroblast cell adhesion. For proteins, we observe the presence of thresholds for surface wettability and electrostatic driving forces necessary to affect adhesion. Beyond these thresholds, the individual effects of electrostatic forces and wettability are observed. For fibroblast, both surface charge and wettability have an effect on its adhesion. The combined effects of positive charge and hydrophilicity lead to the highest cell adhesion, whereas negative charge and hydrophobicity lead to the lowest cell adhesion. Our design strategy can potentially form the basis for studying the distinct behaviors of electrostatic force or wettability driven interfacial phenomena and serve as a reference in future studies assessing protein adsorption and cell adhesion to surfaces with known charge and wettability within the property range studied here.

  8. Like-charge attraction of molecular cations in water: subtle balance between interionic interactions and ionic solvation effect. (United States)

    Inagaki, Taichi; Aono, Shinji; Nakano, Hiroshi; Yamamoto, Takeshi


    Despite strong electrostatic repulsion, like-charged ions in aqueous solution can effectively attract each other via ion-water interactions. In this paper we investigate such an effective interaction of like-charged ions in water by using the 3D-RISM-SCF method (i.e., electronic structure theory combined with three-dimensional integral equation theory for molecular solvents). Free energy profiles are calculated at the CCSD(T) level for a series of molecular ions including guanidinium (Gdm(+)), alkyl-substituted ammonium, and aromatic amine cations. Polarizable continuum model (PCM) and mean-field QM/MM free energy calculations are also performed for comparison. The results show that the stability of like-charged ion pairs in aqueous solution is determined by a very subtle balance between interionic interactions (including dispersion and π-stacking interactions) and ionic solvation/hydrophobic effects and that the Gdm(+) ion has a rather favorable character for like-charge association among all the cations studied. Furthermore, we investigate the like-charge pairing in Arg-Ala-Arg and Lys-Ala-Lys tripeptides in water and show that the Arg-Arg pair has a contact free-energy minimum of about -6 kcal/mol. This result indicates that arginine pairing observed on protein surfaces and interfaces is stabilized considerably by solvation effects.

  9. MOSFET Electric-Charge Sensor (United States)

    Robinson, Paul A., Jr.


    Charged-particle probe compact and consumes little power. Proposed modification enables metal oxide/semiconductor field-effect transistor (MOSFET) to act as detector of static electric charges or energetic charged particles. Thickened gate insulation acts as control structure. During measurements metal gate allowed to "float" to potential of charge accumulated in insulation. Stack of modified MOSFET'S constitutes detector of energetic charged particles. Each gate "floats" to potential induced by charged-particle beam penetrating its layer.

  10. Semiconduction properties of some polyene-iodine charge-transfer complexes and their application in solid-state batteries

    Energy Technology Data Exchange (ETDEWEB)

    Sen, S.; Pal, P.; Misra, T.N. (Indian Association for the Cultivation of Science, Calcutta (India). Dept. of Spectroscopy)


    The conjugated polyenes [beta]-carotene, lutein, retinoic acid and [beta]-apo-8'-carotenal are shown to form charge-transfer (CT) complexes with the electron acceptor iodine. The conductivity increases by several orders of magnitude and the activation energy decreases on CT complex formation. Using these complexes as cathodic material, batteries with the configuration Mg/(polyene-iodine CT complex)/graphite are developed. Different battery parameters are evaluated. The effects of ambient temperature and humidity on battery performance are also studied. Results show that a [beta]-apo-8'-carotenal-1[sub 2] based battery has the maximum power density and longest self-life and is suitable for use as a micro-electronic gadget energizer. (author)

  11. Computer-aided model analysis for ionic strength-dependent effective charge of protein in ion-exchange chromatography

    DEFF Research Database (Denmark)

    Lim, Young-il; Jørgensen, Sten Bay; Kim, In-Ho


    differential algebraic equation (PDAE) system, a fast and accurate numerical method (i.e., conservation element/solution element (CE/SE) method), is proposed. Sensitivity and elasticity of the model parameters (e.g., steric/shape factors, adsorption heat coefficient, effective protein charge, equilibrium...... constant, mass transfer coefficient, axial dispersion coefficient and bed voidage) are analyzed for a BSA-salt system in a low protein concentration range. Within a low concentration range of bovine serum albumin (BSA) where linear adsorption isotherms are shown, the adsorption heat coefficient, shape...... salt concentrations, it is proposed that the effective protein charge could depend upon the salt concentration (or ionic strength). The reason for this dependence may be a steric hindrance of protein binding sites combined with a salt shielding effect neutralizing the surface charges of the protein. (c...

  12. Even-odd effects in the charge distributions of the products of cold fragmentation of actinide nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Koldobskii, A.B.; Sirotkin, V.K.


    We consider even-odd effects in the charge distributions of the products of cold fragmentation of the actinide nuclei. It is shown that these effects are stabilized in the transition to the cold-fragmentation region. Possible causes of this stabilization are found.

  13. Improving nuclease activity of copper(II)-terpyridine complex through solubilizing and charge effects of glycine. (United States)

    Zhou, Wen; Wang, Xiaoyong; Hu, Ming; Guo, Zijian


    Copper complexes are potential metallonucleases that may find application in biotechnology and molecular biology. In this study, a ternary copper-terpyridine complex [Cu(ttpy)(Gly)(NO3)](NO3)·H2O (1) (ttpy=4'-p-tolyl-2,2':6,2″-terpyridine) is synthesized and characterized by X-ray crystallography and ESI-MS as an artificial nuclease. Glycine (Gly) is introduced into the complex to enhance the water-solubility and electrostatic affinity for the nucleic acid target. The interaction between complex 1 and DNA has been studied by spectroscopy and gel electrophoresis, using a structural analog [Cu(ttpy)(NO3)2] (2) as the reference. Complex 1 demonstrates an increased DNA binding ability and oxidative cleavage activity towards supercoiled pBR322 DNA as compared with complex 2. The enhanced water-solubility and positive charge of complex 1 may facilitate its access to DNA and formation of hydrogen bonds with the sugar-phosphate backbone. The results indicate that carefully positioned auxiliary groups in a copper complex can significantly affect the substrate binding or activation ability and consequently the nuclease efficiency of the complex. Copyright © 2012 Elsevier Inc. All rights reserved.

  14. Peculiar charging effects on titania in aqueous 1:1, 2:1, 1:2 and mixed electrolyte suspensions. (United States)

    Rosenholm, Jarl B; Kosmulski, Marek


    Charging of particles in aqueous suspensions is primarily related to potential determining ions, such as silver and iodide ions at silver halide particle surfaces. Proton is considered as a (secondary) potential determining ion at hydrated metal oxide surfaces. Indifferent electrolytes neutralize at increased concentration the surface charge but do not reverse it. However, in the presence of a non-Coulombic interaction the surface charge may be enhanced or reversed at increased ionic strength. Such interaction is denoted specific which may be due to enhanced van der Waals dipolar, Lewis acid-base, solvation (Hofmeister) and/or Born solvation effects. Alternatively, these interactions have been characterized in terms of (semi) empirical ion and surface properties, such as hard-soft acid-base (HSAB) interaction. Within the Stern layer closest to the particle surface truly specific effects are related to the inner Helmholtz plane (IHP) in order to distinguish them from the charge and solvation related effects occurring within the outer Helmholtz plane (OHP). We review some recent observations on the particular influence of ions on the charging of titania particles in aqueous 1:1, 2:1, 1:2 and mixed electrolyte suspensions. Copyright © 2012 Elsevier B.V. All rights reserved.


    Directory of Open Access Journals (Sweden)

    Taufan Wiguna


    Full Text Available Gas charged sediment as a one of parameter for geohazard study in infrastructure especially in swamp area. Instability of sediment layer for exampel subsidence and landslide result in geohazard potention that caused by gas charged sediment. Seismic single channel can be used to identufy gas charged sediment location. Seabed morphology is collected from bathymetry and tidal survey. From seismic profile interpretation shows gas charged sediment indication in Line A and Line B. That indication emerged by presence of acoustic turbid zone and acoustic blanking. Line A and Line B location will be spotlight in next geotechnic port construction study.

  16. Effect of Chemical Charging/Discharging on Plasmonic Behavior of Silver Metal Nanoparticles Prepared using Citrate-Stabilized Cadmium Selenide Quantum Dots. (United States)

    Ingole, Pravin P; Bhat, Mohsin A


    The thermodynamics and kinetics of the chemical and electrochemical charging of a catalyst surface are very important to understand its applicability as a catalyst material, particularly in redox catalysis. Through the present study, we hereby communicate the results obtained from our detailed investigations related to the effect of chemical charging on the plasmonic behavior of silver metal nanoparticles (Ag MNPs) as redox catalysts. Two different batches of Ag MNPs were prepared through thermally assisted chemical reduction of silver ions. The difference in these batches was the use or not of citrate-capped cadmium selenide quantum dots (Q-CdSe) for the reduction of solution-phase silver ions to their colloidal plasmonic phase. The charge on the surfaces of the Ag MNPs was varied by the chemical electron injection method by using BH4(-) ions from a NaBH4 solution. The processes of charging and discharging were monitored by using UV/Vis absorption spectroscopy. The impact of the concentration of the reductant on the charging and discharging processes was also investigated. The Ag MNPs were also tested for their voltammetric response, wherein it was observed that it was more difficult to oxidize the Ag MNPs prepared with Q-CdSe seeds than to oxidize Ag MNPs prepared without Q-CdSe particles. Our results demonstrate that Q-CdSe seeds not only enhance the redox catalytic activity of Ag MNPs but also provide stability towards polarization of their plasmonic behavior. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Observation and simulation of space-charge effects in a radio-frequency photoinjector using a transverse multibeamlet distribution

    Directory of Open Access Journals (Sweden)

    M. Rihaoui


    Full Text Available We report on an experimental study of space-charge effects in a radio-frequency (rf photoinjector. A 5 MeV electron bunch, consisting of a number of beamlets separated transversely, was generated in an rf photocathode gun and propagated in the succeeding drift space. The collective interaction of these beamlets was studied for different experimental conditions. The experiment allowed the exploration of space-charge effects and its comparison with 3D particle-in-cell simulations. Our observations also suggest the possible use of a multibeam configuration to tailor the transverse distribution of an electron beam.

  18. The effect of space charge on beam transport through the injection system of the Lund Pelletron accelerator (United States)

    Dymnikov, A.; Hellborg, R.; Pallon, J.; Skog, G.; Yang, C.; Ohlén, G.


    A new recursive technique is used for the solution of the equations of motion for charged particles, taking into account the effect of space charge. The paraxial equations are solved for an infinitely long beam with an elliptical cross-section in a static electric field. An effective computer code, based on the method of a continuous generalized analogue of the Gauss brackets and on the method of the envelope matrix, has been written. The code has been used to study the beam dynamics in the injection system of the Pelletron electrostatic accelerator in Lund.

  19. Effects of defects and dephasing on charge and spin currents in two-dimensional topological insulators (United States)

    Van Dyke, John S.; Morr, Dirk K.


    Using the nonequilibrium Keldysh Green's function formalism, we investigate the effect of defects on the electronic structure and transport properties of two-dimensional topological insulators (TI). We demonstrate how the spatial flow of charge changes between the topologically protected edge and bulk states and show that elastically and inelastically scattering defects that preserve the time-reversal symmetry of the TI lead to qualitatively different effects on the TI's local electronic structure and its transport properties. Moreover, we show that the recently predicted ability to create highly spin-polarized currents by breaking the time-reversal symmetry of the TI via magnetic defects [J. S. Van Dyke and D. K. Morr, Phys. Rev. B 93, 081401 (2016), 10.1103/PhysRevB.93.081401] is robust against the inclusion of a Rashba spin-orbit interaction and the effects of dephasing, and remains unaffected by changes over a wide range of the TI's parameters. We discuss how the sign of the induced spin currents changes under symmetry operations, such as reversal of bias and gate voltages, or spatial reflections. Finally, we show that the insight into the interplay between topology and symmetry of the magnetic defects can be employed for the creation of intriguing quantum phenomena, such as highly localized magnetic fields inside the TI.

  20. Electrostatic Screening and Charge Correlation Effects in Micellization of Ionic Surfactants

    KAUST Repository

    Jusufi, Arben


    We have used atomistic simulations to study the role of electrostatic screening and charge correlation effects in self-assembly processes of ionic surfactants into micelles. Specifically, we employed grand canonical Monte Carlo simulations to investigate the critical micelle concentration (cmc), aggregation number, and micellar shape in the presence of explicit sodium chloride (NaCl). The two systems investigated are cationic dodecyltrimethylammonium chloride (DTAC) and anionic sodium dodecyl sulfate (SDS) surfactants. Our explicit-salt results, obtained from a previously developed potential model with no further adjustment of its parameters, are in good agreement with experimental data for structural and thermodynamic micellar properties. We illustrate the importance of ion correlation effects by comparing these results with a Yukawa-type surfactant model that incorporates electrostatic screening implicitly. While the effect of salt on the cmc is well-reproduced even with the implicit Yukawa model, the aggregate size predictions deviate significantly from experimental observations at low salt concentrations. We attribute this discrepancy to the neglect of ion correlations in the implicit-salt model. At higher salt concentrations, we find reasonable agreement of the Yukawa model with experimental data. The crossover from low to high salt concentrations is reached when the electrostatic screening length becomes comparable to the headgroup size. © 2009 American Chemical Society.

  1. Removal of charged micropollutants from water by ion-exchange polymers - effects of competing electrolytes

    NARCIS (Netherlands)

    Bäuerlein, P.S.; ter Laak, T.L.; Hofman-Caris, R.C.H.M.; de Voogt, P.; Droge, S.T.J.


    A wide variety of environmental compounds of concern, e.g. pharmaceuticals or illicit drugs, are acids or bases that may predominantly be present as charged species in drinking water sources. These charged micropollutants may prove difficult to remove by currently used water treatment steps (e.g.

  2. Removal of charged micropollutants from water by ion-exchange polymers - Effects of competing electrolytes

    NARCIS (Netherlands)

    Bauerlein, P.S.; ter Laak, T.L.; Hofman-Caris, R.C.; Droge, S.T.J.


    A wide variety of environmental compounds of concern, e.g. pharmaceuticals or illicit drugs, are acids or bases that may predominantly be present as charged species in drinking water sources. These charged micropollutants may prove difficult to remove by currently used water treatment steps (e.g.

  3. Effect of Protein Charge on the Generation of Aggregation-Prone Conformers

    NARCIS (Netherlands)

    Broersen, K.; Weijers, M.; Groot, de J.; Hamer, R.J.; Jongh, de H.H.J.


    This study describes how charge modification affects aggregation of ovalbumin, thereby distinguishing the role of conformational and electrostatic stability in the process. Ovalbumin variants were engineered using chemical methylation or succinylation to obtain a range of protein net charge from -1

  4. Effect of protein charge on the generation of aggregation-prone conformers

    NARCIS (Netherlands)

    Broersen, K.; Weijers, M.; Groot,; Hamer, R.J.; Jongh,


    This study describes how charge modification affects aggregation of ovalbumin, thereby distinguishing the role of conformational and electrostatic stability in the process. Ovalbumin variants were engineered using chemical methylation or succinylation to obtain a range of protein net charge from -1

  5. The effect of national culture on auditor-in-charge involvement

    NARCIS (Netherlands)

    Bik, O.P.G.; Hooghiemstra, R.


    Regulators and professional accounting bodies have identified auditor-in-charge involvement as one of the key indicators of audit quality. A potentially important, yet overlooked, issue is that auditor-in-charge involvement is affected by numerous contextual factors. In this study, we aim at

  6. The Effect of National Culture on Auditor-in-Charge Involvement

    NARCIS (Netherlands)

    Bik, Olof; Hooghiemstra, Reggy


    Regulators and professional accounting bodies have identified auditor-in-charge involvement as one of the key indicators of audit quality. A potentially important, yet overlooked, issue is that auditor-in-charge involvement is affected by numerous contextual factors. In this study, we aim at

  7. Effect of dust size distribution and dust charge fluctuation on dust ion ...

    Indian Academy of Sciences (India)


    Jun 17, 2016 ... Dusty plasma; dust-acoustic shock wave; dust size distribution; adiabatic dust charge variation; negative ions. PACS Nos 52.27.Lw; 52.35.Tc; 52.35.Mw. 1. Introduction ... processes has relation to some phenomena including. Landau damping, collisions between charged particles and neutrals and ...

  8. Positively charged biomaterials exert antimicrobial effects on gram-negative bacilli in rats

    NARCIS (Netherlands)

    Gottenbos, B; van der Mei, HC; Klatter, F; Grijpma, DW; Feijen, J; Nieuwenhuis, P; Busscher, HJ

    Biomaterial-centered infection is a much-dreaded complication associated with the use of biomedical implants. Although positively charged biomaterial surfaces stimulate bacterial adhesion, it has been suggested that surface growth of adhering Gram-negative bacilli is inhibited on positively charged

  9. Effects of charged Higgs bosons in the deep inelastic process ντ N ...

    Indian Academy of Sciences (India)

    section of the charged current .... section rates of the charged current deep inelastic process ντ N in the frame of the. SM and 2HDM(II). In §5 ... scalar products of any two particle four-momenta be positive and the determinant. Pramana – J. Phys.

  10. Long-term RF burn-in effects on dielectric charging of MEMS capacitive switches

    KAUST Repository

    Molinero, David G.


    This paper experimentally quantified the long-term effects of RF burn-in, in terms of burn-in and recovery times, and found the effects to be semipermanent. Specifically, most of the benefit could be realized after approximately 20 min of RF burn-in, which would then last for several months. Additionally, since similar effects were observed on both real and faux switches, the effects appeared to be of electrical rather than mechanical nature. These encouraging results should facilitate the application of the switches in RF systems, where high RF power could be periodically applied to rejuvenate the switches. © 2001-2011 IEEE.

  11. Effective action for reggeized gluons, classical gluon field of relativistic color charge and color glass condensate approach (United States)

    Bondarenko, S.; Lipatov, L.; Prygarin, A.


    We discuss application of formalism of small- x effective action for reggeized gluons (Gribov, Sov. Phys. JETP 26:414, 1968; Lipatov, Nucl. Phys. B 452:369, 1995; Lipatov, Phys. Rep. 286:131, 1997; Lipatov, Subnucl. Ser. 49:131, 2013; Lipatov, Int. J. Mod. Phys. Conf. Ser. 39:1560082, 2015; Lipatov, Int. J. Mod. Phys. A 31(28/29):1645011, 2016; Lipatov, EPJ Web Conf. 125:01010, 2016; Lipatov, Sov. J. Nucl. Phys. 23:338, 1976; Kuraev et al., Sov. Phys. JETP 45:199, 1977; Kuraev et al., Zh Eksp, Teor. Fiz. 72:377, 1977; Balitsky and Lipatov, Sov. J. Nucl. Phys. 28:822, 1978; Balitsky and Lipatov, Yad. Fiz. 28:1597 1978), for the calculation of classical gluon field of relativistic color charge, similarly to that done in CGC approach of McLerran and Venugopalan, Phys. Rev. D 49:2233 (1994), Jalilian-Marian et al., Phys. Rev. D 55:5414 (1997), Jalilian-Marian et al., Nucl. Phys. B 504:415 (1997), Jalilian-Marian et al., Phys. Rev. D 59:014014 (1998), Jalilian-Marian et al., Phys. Rev. D 59:014015 (1998), Iancu et al., Nucl. Phys. A 692:583 (2001), Iancu et al., Phys. Lett. B 510:133 (2001), Ferreiro et al., Nucl. Phys. A 703:489 (2002). The equations of motion with the reggeon fields are solved in LO and NLO approximations and new solutions are found. The results are compared to the calculations performed in the CGC framework and it is demonstrated that the LO CGC results for the classical field are reproduced in our calculations. Possible applications of the NLO solution in the effective action and CGC frameworks are discussed as well.

  12. Effective action for reggeized gluons, classical gluon field of relativistic color charge and color glass condensate approach

    Energy Technology Data Exchange (ETDEWEB)

    Bondarenko, S.; Prygarin, A. [Ariel University, Physics Department, Ariel (Israel); Lipatov, L. [St. Petersburg Nuclear Physics Institute, Saint Petersburg (Russian Federation); Hamburg University, II Institute of Theoretical Physics, Hamburg (Germany)


    We discuss application of formalism of small-x effective action for reggeized gluons (Gribov, Sov. Phys. JETP 26:414, 1968; Lipatov, Nucl. Phys. B 452:369, 1995; Lipatov, Phys. Rep. 286:131, 1997; Lipatov, Subnucl. Ser. 49:131, 2013; Lipatov, Int. J. Mod. Phys. Conf. Ser. 39:1560082, 2015; Lipatov, Int. J. Mod. Phys. A 31(28/29):1645011, 2016; Lipatov, EPJ Web Conf. 125:01010, 2016; Lipatov, Sov. J. Nucl. Phys. 23:338, 1976; Kuraev et al., Sov. Phys. JETP 45:199, 1977; Kuraev et al., Zh Eksp, Teor. Fiz. 72:377, 1977; Balitsky and Lipatov, Sov. J. Nucl. Phys. 28:822, 1978; Balitsky and Lipatov, Yad. Fiz. 28:1597 1978), for the calculation of classical gluon field of relativistic color charge, similarly to that done in CGC approach of McLerran and Venugopalan, Phys. Rev. D 49:2233 (1994), Jalilian-Marian et al., Phys. Rev. D 55:5414 (1997), Jalilian-Marian et al., Nucl. Phys. B 504:415 (1997), Jalilian-Marian et al., Phys. Rev. D 59:014014 (1998), Jalilian-Marian et al., Phys. Rev. D 59:014015 (1998), Iancu et al., Nucl. Phys. A 692:583 (2001), Iancu et al., Phys. Lett. B 510:133 (2001), Ferreiro et al., Nucl. Phys. A 703:489 (2002). The equations of motion with the reggeon fields are solved in LO and NLO approximations and new solutions are found. The results are compared to the calculations performed in the CGC framework and it is demonstrated that the LO CGC results for the classical field are reproduced in our calculations. Possible applications of the NLO solution in the effective action and CGC frameworks are discussed as well. (orig.)

  13. The Effects of Space-Charge on the Dynamics of the Ion Booster in the Jefferson Lab EIC (JLEIC)

    Energy Technology Data Exchange (ETDEWEB)

    Bogacz, Alex [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Nissen, Edward [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)


    Optimization of the booster synchrotron design to operate in the extreme space-charge dominated regime is proposed. This study is motivated by the ultra-high luminosity promised by the JLEIC accelerator complex, which poses several beam dynamics and lattice design challenges for its individual components. We examine the effects of space charge on the dynamics of the booster synchrotron for the proposed JLEIC electron ion collider. This booster will inject and accumulate protons and heavy ions at an energy of 280 MeV and then engage in a process of acceleration and electron cooling to bring it to its extraction energy of 8 GeV. This would then be sent into the ion collider ring part of JLEIC. In order to examine the effects of space charge on the dynamics of this process we use the software SYNERGIA.

  14. The two-nucleon electromagnetic charge operator in chiral effective field theory ($\\chi$EFT) up to one loop

    Energy Technology Data Exchange (ETDEWEB)

    S. Pastore,L. Girlanda,R. Schiavilla,M. Viviani,S. Pastore,L. Girlanda,R. Schiavilla,M. Viviani


    The electromagnetic charge operator in a two-nucleon system is derived in chiral effective field theory ($\\chi$EFT) up to order $e\\, Q$ (or N4LO), where $Q$ denotes the low-momentum scale and $e$ is the electric charge. The specific form of the N3LO and N4LO corrections from, respectively, one-pion-exchange and two-pion-exchange depends on the off-the-energy-shell prescriptions adopted for the non-static terms in the corresponding potentials. We show that different prescriptions lead to unitarily equivalent potentials and accompanying charge operators. Thus, provided a consistent set is adopted, predictions for physical observables will remain unaffected by the non-uniqueness associated with these off-the-energy-shell effects.

  15. Energy level alignment at metal/organic semiconductor interfaces: "pillow" effect, induced density of interface states, and charge neutrality level. (United States)

    Vázquez, H; Dappe, Y J; Ortega, J; Flores, F


    A unified model, embodying the "pillow" effect and the induced density of interface states (IDIS) model, is presented for describing the level alignment at a metal/organic interface. The pillow effect, which originates from the orthogonalization of the metal and organic wave functions, is calculated using a many-body linear combination of atomic orbitals Hamiltonian, whereby electron long-range interactions are obtained using an expansion in the metal/organic wave function overlap, while the electronic charge of both materials remains unchanged. This approach yields the pillow dipole and represents the first effect induced by the metal/organic interaction, resulting in a reduction of the metal work function. In a second step, we consider how charge is transferred between the metal and the organic material by means of the IDIS model: Charge transfer is determined by the relative position of the metal work function (corrected by the pillow effect) and the organic charge neutrality level, as well as by an interface parameter S, which measures how this potential difference is screened. In our approach, we show that the combined IDIS-pillow effects can be described in terms of the original IDIS alignment corrected by a screened pillow dipole. For the organic materials considered in this paper, we see that the IDIS dipole already represents most of the realignment induced at the metal/organic interface. We therefore conclude that the pillow effect yields minor corrections to the IDIS model.

  16. The effect of a patient charge and a prescription regulation on the use of antihypertension drugs in Limburg, The Netherlands. (United States)

    Starmans, B; Janssen, R; Schepers, M; Verkooijen, M


    On 1 February 1983 a patient charge was introduced for prescription drugs for persons insured under the Dutch Sickness Funds Insurance Act. The charge consisted of a co-payment of NLG 2.50 per prescription item up to a maximum of NLG 125 for each family per calendar year. In the period before the introduction of the charge a prescription regulation was in force. For the majority of drugs this rule directed that each prescription item should be for a dosage of not more than 30 days. The prescription regulation was officially introduced on 1 January 1981 and ceased with the introduction of the charge. The effect of both measures on the use of antihypertension drugs in Limburg was investigated in an interrupted time-series analysis. Both the prescription regulation and the charge appeared to have an effect on the number of prescription items per insurant and the number of units delivered per prescription item. However, neither measure resulted in a reduction in the number of units delivered per insurant or the number of 'defined daily doses' (DDDs) per insurant. These findings suggest that neither measure resulted in a decrease in the inappropriate or appropriate use of antihypertension drugs.

  17. Effect of Size, Surface Charge, and Hydrophobicity of Poly(amidoamine) Dendrimers on Their Skin Penetration (United States)

    Yang, Yang; Sunoqrot, Suhair; Stowell, Chelsea; Ji, Jingli; Lee, Chan-Woo; Kim, Jin Woong; Khan, Seema A.; Hong, Seungpyo


    The barrier functions of the stratum corneum (SC) and the epidermal layers present a tremendous challenge in achieving effective transdermal delivery of drug molecules. Although a few reports have shown that poly(amidoamine) (PAMAM) dendrimers are effective skin penetration enhancers, little is known regarding the fundamental mechanisms behind the dendrimer-skin interactions. In this paper, we have performed a systematic study to better elucidate how dendrimers interact with skin layers depending on their size and surface groups. Franz diffusion cells and confocal microscopy were employed to observe dendrimer interactions with full-thickness porcine skin samples. We have found that smaller PAMAM dendrimers (generation 2 (G2)) penetrate the skin layers more efficiently than the larger ones (G4). We have also found that G2 PAMAM dendrimers that are surface modified by either acetylation or carboxylation exhibit increased skin permeation and likely diffuse through an extracellular pathway. In contrast, amine-terminated dendrimers show enhanced cell internalization and skin retention but reduced skin permeation. In addition, conjugation of oleic acid (OA) to G2 dendrimers increases their 1-octanol/PBS partition coefficient, resulting in increased skin absorption and retention. Here we report that size, surface charge, and hydrophobicity directly dictate the permeation route and efficiency of dendrimer translocation across the skin layers, providing a design guideline for engineering PAMAM dendrimers as a potential transdermal delivery vector. PMID:22621160

  18. Charge densities and charge noise in mesoscopic conductors

    Indian Academy of Sciences (India)

    February 2002 physics pp. 241–257. Charge densities and charge noise in mesoscopic conductors ... the charge noise [6] based on the scattering approach. Similar to the discussion of linear ...... a novel resistance which determines the dissipative effects in charging and decharging a. 254. Pramana – J. Phys., Vol. 58, No.

  19. Radiobiology with heavy charged particles: a historical review

    Energy Technology Data Exchange (ETDEWEB)

    Skarsgard, L.D. [Dept. of Medical Biophysics, B.C. Cancer Research Centre and TRIUMF, Vancouver (Canada)


    The presentation will attempt to briefly review some of radiobiological data on the effects of heavy charged particles and to discuss the influence of those studies on the clinical application which followed. (orig./MG)

  20. Effect of Conjugation Length on Photoinduced Charge-Transfer in π-Conjugated Oligomer-Acceptor Dyads

    KAUST Repository

    Jiang, Junlin


    A series of -conjugated oligomer-acceptor dyads were synthesized that feature oligo(phenylene ethynylene) (OPE) conjugated backbones end-capped with a naphthalene diimide (NDI) acceptor. The OPE segments vary in length from 4 to 8 phenylene ethynene units (PEn-NDI, where n = 4, 6 and 8). Fluorescence and transient absorption spectroscopy reveals that intramolecular OPE NDI charge transfer dominates the deactivation of excited states of the PEn-NDI oligomers. Both charge separation (CS) and charge recombination (CR) are strongly exothermic (G0CS ~ -1.1 and G0CR ~ -2.0 eV), and the driving forces do not vary much across the series because the oxidation and reduction potentials and singlet energies of the OPEs do not vary much with their length. Bimolecular photoinduced charge transfer between model OPEs that do not contain the NDI acceptors with methyl viologen was studied, and the results reveal that the absorption of the cation radical state (OPE+•) remains approximately constant ( ~ 575 nm) regardless of oligomer length. This finding suggests that the cation radical (polaron) of the OPE is relatively localized, effectively occupying a confined segment of n 4 repeat units in the longer oligomers. Photoinduced intramolecular electron transfer dynamics in the PEn-NDI series was investigated by UV-visible femtosecond transient absorption spectroscopy with visible and mid-infrared probes. Charge separation occurs on the 1 – 10 ps timescale, with the rates decreasing slightly with increased oligomer length (βCS ~ 0.15 Å-1). The rate for charge-recombination decreases in the sequence PE4-NDI > PE6-NDI ~ PE8-NDI. The discontinuous distance dependence in the rate for charge recombination may be related to the spatial localization of the positive polaron state in the longer oligomers.

  1. Implementation of Space Charge Forces in BimBim

    CERN Document Server

    Gottlob, Emmanuel; Oeftiger, Adrian

    An numerical algorithm is described for the implementation of linearised coherent space charge forces into BimBim, an eigenvalue solver for the coherent modes of oscillation of multibunch beams in the presence of beam coupling impedance, beam-beam, transverse feedback and now space charge effects. First results obtained with the model are described and compared to existing results where applicable.

  2. Effect of β--charged eradiation and its calculation in the nuclear electrodynamics theory (United States)

    Tertychny-Dauri, V. Yu


    The study of own fields and charged particles motion and also charged fission splinters of a heavy nucleuses into nonrelativistic approximation is the subject of this paper research. The main efforts are concentrated in quest of charged share components by the radioactive β--disintegration. The corresponding field equations and equations of motion in the nuclear electrodynamics processes are obtained and their solutions are found. Analysis of the microscopic equations is generalized to the level of the macroscopic description of continuous medium electrodynamics and is accompanied by quantumomechanical additions.

  3. Quantum effects in the capture of charged particles by dipolar polarizable symmetric top molecules. I. General axially nonadiabatic channel treatment. (United States)

    Auzinsh, M; Dashevskaya, E I; Litvin, I; Nikitin, E E; Troe, J


    The rate coefficients for capture of charged particles by dipolar polarizable symmetric top molecules in the quantum collision regime are calculated within an axially nonadiabatic channel approach. It uses the adiabatic approximation with respect to rotational transitions of the target within first-order charge-dipole interaction and takes into account the gyroscopic effect that decouples the intrinsic angular momentum from the collision axis. The results are valid for a wide range of collision energies (from single-wave capture to the classical limit) and dipole moments (from the Vogt-Wannier and fly-wheel to the adiabatic channel limit).

  4. Measuring the equity effects of a carbon charge on car commuters: A case study of Manchester Airport

    NARCIS (Netherlands)

    Miyoshi, C.; Rietveld, P.


    This papers attempts to quantify the equity effect of a hypothesized economic instrument, a carbon charge on car commuters, for reducing carbon dioxide emissions produced by commuters on airport surface access. Manchester Airport is taken as a case study using staff Survey data from 2008 and 2010.

  5. Dielectric interface-dependent spatial charge distribution in ambipolar polymer semiconductors embedded in dual-gate field-effect transistors

    NARCIS (Netherlands)

    Lee, J.; Roelofs, W.S.C.; Janssen, R.A.J.; Gelinck, G.H.


    The spatial charge distribution in diketopyrrolopyrrole-containing ambipolar polymeric semiconductors embedded in dual-gate field-effect transistors (DGFETs) was investigated. The DGFETs have identical active channel layers but two different channel/gate interfaces, with a CYTOP™ organic dielectric

  6. Fast Atomic Charge Calculation for Implementation into a Polarizable Force Field and Application to an Ion Channel Protein

    Directory of Open Access Journals (Sweden)

    Raiker Witter


    Full Text Available Polarization of atoms plays a substantial role in molecular interactions. Class I and II force fields mostly calculate with fixed atomic charges which can cause inadequate descriptions for highly charged molecules, for example, ion channels or metalloproteins. Changes in charge distributions can be included into molecular mechanics calculations by various methods. Here, we present a very fast computational quantum mechanical method, the Bond Polarization Theory (BPT. Atomic charges are obtained via a charge calculation method that depend on the 3D structure of the system in a similar way as atomic charges of ab initio calculations. Different methods of population analysis and charge calculation methods and their dependence on the basis set were investigated. A refined parameterization yielded excellent correlation of R=0.9967. The method was implemented in the force field COSMOS-NMR and applied to the histidine-tryptophan-complex of the transmembrane domain of the M2 protein channel of influenza A virus. Our calculations show that moderate changes of side chain torsion angle χ1 and small variations of χ2 of Trp-41 are necessary to switch from the inactivated into the activated state; and a rough two-side jump model of His-37 is supported for proton gating in accordance with a flipping mechanism.

  7. The effect of laser contrast on generation of highly charged Fe ions by ultra-intense femtosecond laser pulses (United States)

    Faenov, Anatoly Ya.; Alkhimova, Maria A.; Pikuz, Tatiana A.; Skobelev, Igor Yu.; Nishiuchi, Mamiko; Sakaki, Hironao; Pirozhkov, Alexander S.; Sagisaka, Akito; Dover, Nicholas P.; Kondo, Kotaro; Ogura, Koichi; Fukuda, Yuji; Kiriyama, Hiromitsu; Andreev, Alexander; Nishitani, Keita; Miyahara, Takumi; Watanabe, Yukinobu; Pikuz, Sergey A.; Kando, Masaki; Kodama, Ruosuke; Kondo, Kiminori


    Experimental studies on the formation of highly charged ions of medium-Z elements using femtosecond laser pulses with different contrast levels were carried out. Multiply charged Fe ions were generated by laser pulses with 35 fs duration and an intensity exceeding 1021 W/cm2. Using high-resolution X-ray spectroscopic methods, bulk electron temperature of the generated plasma has been identified. It is shown that the presence of a laser pre-pulse at a contrast level of 105-106 with respect to the main pulse drastically decreases the degree of Fe ionization. We conclude that an effective source of energetic, multiply charged moderate and high- Z ions based on femtosecond laser-plasma interactions can be created only using laser pulses of ultra-high contrast.

  8. Vacuum space charge effects in sub-picosecond soft X-ray photoemission on a molecular adsorbate layer

    Directory of Open Access Journals (Sweden)

    M. Dell'Angela


    Full Text Available Vacuum space charge induced kinetic energy shifts of O 1s and Ru 3d core levels in femtosecond soft X-ray photoemission spectra (PES have been studied at a free electron laser (FEL for an oxygen layer on Ru(0001. We fully reproduced the measurements by simulating the in-vacuum expansion of the photoelectrons and demonstrate the space charge contribution of the high-order harmonics in the FEL beam. Employing the same analysis for 400 nm pump-X-ray probe PES, we can disentangle the delay dependent Ru 3d energy shifts into effects induced by space charge and by lattice heating from the femtosecond pump pulse.

  9. Vacuum space charge effects in sub-picosecond soft X-ray photoemission on a molecular adsorbate layer. (United States)

    Dell'Angela, M; Anniyev, T; Beye, M; Coffee, R; Föhlisch, A; Gladh, J; Kaya, S; Katayama, T; Krupin, O; Nilsson, A; Nordlund, D; Schlotter, W F; Sellberg, J A; Sorgenfrei, F; Turner, J J; Öström, H; Ogasawara, H; Wolf, M; Wurth, W


    Vacuum space charge induced kinetic energy shifts of O 1s and Ru 3d core levels in femtosecond soft X-ray photoemission spectra (PES) have been studied at a free electron laser (FEL) for an oxygen layer on Ru(0001). We fully reproduced the measurements by simulating the in-vacuum expansion of the photoelectrons and demonstrate the space charge contribution of the high-order harmonics in the FEL beam. Employing the same analysis for 400 nm pump-X-ray probe PES, we can disentangle the delay dependent Ru 3d energy shifts into effects induced by space charge and by lattice heating from the femtosecond pump pulse.

  10. Heavy Charged Particle Radiobiology: Using Enhanced Biological Effectiveness and Improved Beam Focusing to Advance Cancer Therapy (United States)

    Allen, Christopher; Borak, Thomas B.; Tsujii, Hirohiko; Nickoloff, Jac A.


    Ionizing radiation causes many types of DNA damage, including base damage and single- and double-strand breaks. Photons, including X-rays and γ-rays, are the most widely used type of ionizing radiation in radiobiology experiments, and in radiation cancer therapy. Charged particles, including protons and carbon ions, are seeing increased use as an alternative therapeutic modality. Although the facilities needed to produce high energy charged particle beams are more costly than photon facilities, particle therapy has shown improved cancer survival rates, reflecting more highly focused dose distributions and more severe DNA damage to tumor cells. Despite early successes of charged particle radiotherapy, there is room for further improvement, and much remains to be learned about normal and cancer cell responses to charged particle radiation. PMID:21376738

  11. Surface charges effects on the 2D conformation of supercoiled DNA

    CERN Document Server

    Schmatko, Tatiana; Maaloum, Mounir


    We have adsorbed plasmid PuC19 DNA on a supported bilayer. The mobility of the lipids within the bilayer ensured a 2D equilibrium of the DNA molecule. By varying the fraction of cationic lipids in the membrane, we have tuned the surface charge. Plasmids conformations were imaged by Atomic Force Microscopy (AFM).We performed two sets of experiments: deposition from salt free solution on charged bilayers and deposition from salty solutions on neutral bilayers. Plasmids can be seen as rings, completely opened structures, or tightly supercoiled plectonemes, depending on the experimental conditions. The plectonemic conformation is observed either on charged surfaces (in the absence of salt) or at 30 mM salt concentration on a neutral bilayer. We demonstrate the equivalence of surface screening by mobile interfacial charges and bulk screening from salt ions.

  12. Effects of atamp-charging coke making on strength and high temperature thermal properties of coke. (United States)

    Zhang, Yaru; Bai, Jinfeng; Xu, Jun; Zhong, Xiangyun; Zhao, Zhenning; Liu, Hongchun


    The stamp-charging coke making process has some advantages of improving the operation environment, decreasing fugitive emission, higher gas collection efficiency as well as less environmental pollution. This article describes the different structure strength and high temperature thermal properties of 4 different types of coke manufactured using a conventional coking process and the stamp-charging coke making process. The 4 kinds of cokes were prepared from the mixture of five feed coals blended by the petrography blending method. The results showed that the structure strength indices of coke prepared using the stamp-charging coke method increase sharply. In contrast with conventional coking process, the stamp-charging process improved the coke strength after reaction but had little impact on the coke reactivity index. Copyright © 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

  13. Heavy charged particle radiobiology: using enhanced biological effectiveness and improved beam focusing to advance cancer therapy. (United States)

    Allen, Christopher; Borak, Thomas B; Tsujii, Hirohiko; Nickoloff, Jac A


    Ionizing radiation causes many types of DNA damage, including base damage and single- and double-strand breaks. Photons, including X-rays and γ-rays, are the most widely used type of ionizing radiation in radiobiology experiments, and in radiation cancer therapy. Charged particles, including protons and carbon ions, are seeing increased use as an alternative therapeutic modality. Although the facilities needed to produce high energy charged particle beams are more costly than photon facilities, particle therapy has shown improved cancer survival rates, reflecting more highly focused dose distributions and more severe DNA damage to tumor cells. Despite early successes of charged particle radiotherapy, there is room for further improvement, and much remains to be learned about normal and cancer cell responses to charged particle radiation. 2011 Elsevier B.V. All rights reserved.

  14. Effect of protein charge on the generation of aggregation-prone conformers. (United States)

    Broersen, Kerensa; Weijers, Mireille; de Groot, Jolan; Hamer, Rob J; de Jongh, Harmen H J


    This study describes how charge modification affects aggregation of ovalbumin, thereby distinguishing the role of conformational and electrostatic stability in the process. Ovalbumin variants were engineered using chemical methylation or succinylation to obtain a range of protein net charge from -1 to -26. Charge modification significantly affected the denaturation temperature. From urea-induced equilibrium denaturation studies, it followed that unfolding proceeded via an intermediate state. However, the heat-induced denaturation process could still be described as a two-state irreversible unfolding transition, suggesting that the occurrence of an intermediate has no influence on the kinetics of unfolding. By monitoring the aggregation kinetics, the net charge was found not to be discriminative in the process. It is concluded that the dominant factor determining ovalbumin aggregation propensity is the rate of denaturation and not electrostatic repulsive forces.

  15. Ultrafast Charge Transfer in Nickel Phthalocyanine Probed by Femtosecond Raman-Induced Kerr Effect Spectroscopy (United States)


    The recently developed technique of femtosecond stimulated Raman spectroscopy, and its variant, femtosecond Raman-induced Kerr effect spectroscopy (FRIKES), offer access to ultrafast excited-state dynamics via structurally specific vibrational spectra. We have used FRIKES to study the photoexcitation dynamics of nickel(II) phthalocyanine with eight butoxy substituents, NiPc(OBu)8. NiPc(OBu)8 is reported to have a relatively long-lived ligand-to-metal charge-transfer (LMCT) state, an essential characteristic for efficient electron transfer in photocatalysis. Following photoexcitation, vibrational transitions in the FRIKES spectra, assignable to phthalocyanine ring modes, evolve on the femtosecond to picosecond time scales. Correlation of ring core size with the frequency of the ν10 (asymmetric C–N stretching) mode confirms the identity of the LMCT state, which has a ∼500 ps lifetime, as well as that of a precursor d-d excited state. An even earlier (∼0.2 ps) transient is observed and tentatively assigned to a higher-lying Jahn–Teller-active LMCT state. This study illustrates the power of FRIKES spectroscopy in elucidating ultrafast molecular dynamics. PMID:24841906

  16. Forces in EDO-TTF: Theoretical study of isotope and charge effects on vibronic coupling (United States)

    Tokunaga, Ken

    Isotope and charge effects on vibronic coupling constant (V) and energy gradient (g) of ethylenedioxy-tetrathiafulvalen (EDO-TTF) upon the electron injection into cation and electron removal from neutral molecule are investigated. It is found that normal modes which include C = C stretching motion generally have large V and g. For electron removal, three normal modes (v460, v470, and v480) have large Vi+ and gi+, and deuteration results in decrease of V46+ and increase of V47+. For electron injection, five normal modes (ν+42, ν+44, ν+45, ν+47, and ν+48) have large vi0 and gi0 deuteration results in increase of V045 and V048 and decrease of V047. From the analysis of vibronic coupling constants using vibronic coupling density (VCD), regional vibronic coupling constant (RVCC), and atomic vibronic coupling constant (AVCC), it is revealed that the change in normal mode vectors (d) due to the deuteration and electron removal (or injection) leads to the change in V.

  17. A novel technique for compensation of space charge effects in the LUPIN-II detector (United States)

    Cassell, C.; Ferrarini, M.; Rosenfeld, A.; Caresana, M.


    A new method for improving REM counter performance in Pulsed Neutron Fields (PNFs) has been developed. This method uses an analysis of the build-up of space charge in the counter to compensate for an underestimation of Ambient Dose Equivalent (H*(10)) in intense pulsed fields. It was applied to three sets of experimental data acquired using the LUPIN-II REM counter device, which is designed for use in PNFs. The data was acquired using the cyclotron at Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), at the HiRadMat facility at CERN and at the 'Elettra Sincrotrone Trieste' (ELETTRA), Italy. A comparison of the data with and without this compensation method is used to highlight its effectiveness. The LUPIN-II performance, which has already been shown to be able to cope with fields of up to hundreds of nSv/burst, is improved by at least one order of magnitude, with further potential for improvement.

  18. Carrier mobility in mesoscale heterogeneous organic materials: Effects of crystallinity and anisotropy on efficient charge transport (United States)

    Kobayashi, Hajime; Shirasawa, Raku; Nakamoto, Mitsunori; Hattori, Shinnosuke; Tomiya, Shigetaka


    Charge transport in the mesoscale bulk heterojunctions (BHJs) of organic photovoltaic devices (OPVs) is studied using multiscale simulations in combination with molecular dynamics, the density functional theory, the molecular-level kinetic Monte Carlo (kMC) method, and the coarse-grained kMC method, which was developed to estimate mesoscale carrier mobility. The effects of the degree of crystallinity and the anisotropy of the conductivity of donors on hole mobility are studied for BHJ structures that consist of crystalline and amorphous pentacene grains that act as donors and amorphous C60 grains that act as acceptors. We find that the hole mobility varies dramatically with the degree of crystallinity of pentacene because it is largely restricted by a low-mobility amorphous region that occurs in the hole transport network. It was also found that the percolation threshold of crystalline pentacene is relatively high at approximately 0.6. This high percolation threshold is attributed to the 2D-like conductivity of crystalline pentacene, and the threshold is greatly improved to a value of approximately 0.3 using 3D-like conductive donors. We propose essential guidelines to show that it is critical to increase the degree of crystallinity and develop 3D conductive donors for efficient hole transport through percolative networks in the BHJs of OPVs.

  19. Observation of charge-dependent azimuthal correlations in pPb collisions with CMS and its implication for the search of the Chiral Magnetic Effect

    CERN Document Server

    Tu, Zhoudunming


    Charge-dependent azimuthal correlations relative to the event plane in AA collisions have been suggested as providing evidence for the chiral magnetic effect (CME) caused by local strong parity violation. However, the observation of the CME remains inconclusive because of several possible sources of background correlations that may account for part or all of the observed signals. This talk will present the first application of three-particle, charge-dependent azimuthal correlation analysis in proton-nucleus collisions, using pPb data collected with the CMS experiment at the LHC at $\\sqrt{s_{NN}}$ = 5.02 TeV. The differences found in comparing same and opposite sign correlations are studied as a function of event multiplicity and the pseudorapidity gap between two of the particles detected in the CMS tracker detector. After selecting events with comparable charge-particle multiplicities, the results for pPb collisions are found to be similar to those for PbPb collisions collected at the same collision energy. ...

  20. Poling effect of a charge-trapping layer in glass waveguides

    DEFF Research Database (Denmark)

    Ren, Yitao; Marckmann, Carl Johan; Jacobsen, Rune Shim


    Germanium-doped multi-layer waveguides containing a silicon oxy-nitride layer as a charge trapper are thermally poled in an air environment. Compared to the waveguides without the trapping layer, the induced linear electro-optic coefficient increases more than 20%. A comparable rise in the internal...... field is found. Our results demonstrate an optimization of the optical nonlinearity by shaping the built-in internal field with the charge-trapping layer....

  1. Effect of hydrogen charging on the mechanical properties of medium strength aluminium alloys 2091 and 2014

    DEFF Research Database (Denmark)

    Bandopadhyay, A.; Ambat, Rajan; Dwarakadasa, E.S.


    Cathodic hydrogen charging in 3.5% NaCl solution altered the mechanical properties of 2091-T351 (Al-Cu-Li-Mg-Zr) determined by a slow (10(-3)/s) strain rate tensile testing technique. UTS and YS decreased in the caw of 2091-T351 and 2014-T6(Al-Cu-Mn-Si-Mg) with increase in charging current density...

  2. Modular Symmetry and Fractional Charges in N = 2 Supersymmetric Yang-Mills and the Quantum Hall Effect

    Directory of Open Access Journals (Sweden)

    Brian P. Dolan


    Full Text Available The parallel rôles of modular symmetry in N = 2 supersymmetric Yang-Mills and in the quantum Hall effect are reviewed. In supersymmetric Yang-Mills theories modular symmetry emerges as a version of Dirac's electric - magnetic duality. It has significant consequences for the vacuum structure of these theories, leading to a fractal vacuum which has an infinite hierarchy of related phases. In the case of N = 2 supersymmetric Yang-Mills in 3+1 dimensions, scaling functions can be defined which are modular forms of a subgroup of the full modular group and which interpolate between vacua. Infra-red fixed points at strong coupling correspond to θ-vacua with θ a rational number that, in the case of pure SUSY Yang-Mills, has odd denominator. There is a mass gap for electrically charged particles which can carry fractional electric charge. A similar structure applies to the 2+1 dimensional quantum Hall effect where the hierarchy of Hall plateaux can be understood in terms of an action of the modular group and the stability of Hall plateaux is due to the fact that odd denominator Hall conductivities are attractive infra-red fixed points. There is a mass gap for electrically charged excitations which, in the case of the fractional quantum Hall effect, carry fractional electric charge.

  3. Space-charge dynamics in ultra-cold ion bunches (United States)

    Scholten, Robert; Murphy, Dene; Speirs, Rory; Thompson, Daniel; Sparkes, Benjamin; McCulloch, Andrew


    Cold ion sources based on photoionisation of laser cooled atoms provide a unique system for investigating Coulomb interactions within complex charged particle bunches. Space-charge driven expansion in charged particle beams is of critical importance for applications including electron and ion microscopy, mass spectrometry, synchrotrons and x-ray free electron lasers, and in electron diffraction where space-charge effects constrain the capacity to obtain diffraction information. Self-field effects are often difficult to observe because of thermal diffusion with traditional sources. Cold atom sources produce ions with temperatures of a few mK, such that subtle space-charge effects are apparent. We illustrate the capabilities through detailed investigation of a complex ion bunch shape, showing collective behaviour including high density caustics and shockwave structures arising from long-range interactions between small charge bunches.

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

  5. Analysing the Effect on CMB in a Parity and Charge Parity Violating Varying Alpha Theory

    Energy Technology Data Exchange (ETDEWEB)

    Maity, Debaprasad; /NCTS, Taipei /Taiwan, Natl. Taiwan U.; Chen, Pisin; /NCTS, Taipei /Taiwan, Natl. Taiwan U. /KIPAC, Menlo Park /SLAC


    In this paper we study in detail the effect of our recently proposed model of parity and charge-parity (PCP) violating varying alpha on the Cosmic Microwave Background (CMB) photon passing through the intra galaxy-cluster medium (ICM). The ICM is well known to be composed of magnetized plasma. According to our model, the polarization and intensity of the CMB would be affected when traversing through the ICM due to non-trivial scalar photon interactions. We have calculated the evolution of such polarization and intensity collectively, known as the stokes parameters of the CMB photon during its journey through the ICM and tested our results against the Sunyaev-Zel'dovich (SZ) measurement on Coma galaxy cluster. Our model contains a PCP violating parameter, {beta}, and a scale of alpha variation {omega}. Using the derived constrained on the photon-to-scalar conversion probability, {bar P}{sub {gamma}{yields}{phi}}, for Coma cluster in ref.[34] we found a contour plot in the ({omega},{beta}) parameter plane. The {beta} = 0 line in this parameter space corresponds to well-studied Maxwell-dilaton type models which has lower bound on {omega} {approx}> 6.4 x 10{sup 9} GeV. In general, as the absolute value of {beta} increases, lower bound on {omega} also increases. Our model in general predicts the modification of the CMB polarization with a non-trivial dependence on the parity violating coupling parameter {beta}. However, it is unconstrained in this particular study. We show that this effect can in principle be detected in the future measurements on CMB polarization such that {beta} can also be constrained.

  6. The influence of microstructure on charge separation dynamics in organic bulk heterojunction materials for solar cell applications

    KAUST Repository

    Scarongella, Mariateresa


    Light-induced charge formation is essential for the generation of photocurrent in organic solar cells. In order to gain a better understanding of this complex process, we have investigated the femtosecond dynamics of charge separation upon selective excitation of either the fullerene or the polymer in different bulk heterojunction blends with well-characterized microstructure. Blends of the pBTTT and PBDTTPD polymers with PCBM gave us access to three different scenarios: either a single intermixed phase, an intermixed phase with additional pure PCBM clusters, or a three-phase microstructure of pure polymer aggregates, pure fullerene clusters and intermixed regions. We found that ultrafast charge separation (by electron or hole transfer) occurs predominantly in intermixed regions, while charges are generated more slowly from excitons in pure domains that require diffusion to a charge generation site. The pure domains are helpful to prevent geminate charge recombination, but they must be sufficiently small not to become exciton traps. By varying the polymer packing, backbone planarity and chain length, we have shown that exciton diffusion out of small polymer aggregates in the highly efficient PBDTTPD:PCBM blend occurs within the same chain and is helped by delocalization. This journal is © the Partner Organisations 2014.

  7. Charge carrier-LO phonon interaction in ZnO nanostructures: effect on photocatalytic activity and infrared optical constants (United States)

    Banerjee, Shiny; Bhattacharyya, Puja; Ghosh, Chandan Kumar


    The tunability of electronic and optical properties of zinc oxide (ZnO) is pivotal for its various optoelectronic and catalytic applications. The present work presents the growth of various morphologies such as needle-like (sample A), hedgehog flower-like (sample B) and star flower-like (sample C) of ZnO by changing stirring time and alkaline concentration during hydrothermal method. The synthesized nanostructures are characterized by X-ray diffraction, field emission scanning electron microscope, high resolution transmission electron microscope, Raman spectroscopy, photoluminescence spectroscopy and Fourier transform infrared spectroscopy. Optical constants such as refractive index, extinction coefficient in the infrared region are evaluated by Kramer-Krönig method. Congo red, taken as a model dye, is used to investigate the degradation efficiency of the synthesized nanostructures. Interestingly, it has been observed that the stirring and alkaline concentration have significant effect to generate different morphologies of ZnO. Each morphology containing various defect (oxygen vacancies, zinc vacancies) concentration exhibits different catalytic degradation efficiencies (ranging from 49.5 to 71.1%). Raman spectra reveals different shifts corresponding to LO phonon mode for different ZnO morphologies (595.7, 596.9 and 593.6 cm-1 for samples `A', `B' and `C', respectively). It has been noticed further that the generated morphologies possesses different charge carrier-LO phonon interaction, parameterized by Huang-Rhys `S' factor as analyzed from Raman and luminescence spectroscopy, that has strong effect on its luminescence, catalytic properties as well as on optical constants.


    Energy Technology Data Exchange (ETDEWEB)

    Clarke, John


    The purpose of this article is to review the theory of charge imbalance, and to discuss its relevance to a number of experimental situations. We introduce the concepts of quasiparticle charge and charge imbalance, and discuss the generation and detection of charge imbalance by tunneling. We describe the relaxation of the injected charge imbalance by inelastic scattering processes, and show how the Boltzmann equation can be solved to obtain the steady state quasiparticle distribution and the charge relaxation rate. Details are given of experiments to measure charge imbalance and the charge relaxation rate when inelastic scattering is the predominant relaxation mechanism. Experiments on and theories of other charge relaxation mechanisms are discussed, namely relaxation via elastic scattering in the presence of energy gap anisotropy, or in the presence of a pair breaking mechanism such as magnetic impurities or an applied supercurrent or magnetic field. We describe three other situations in which charge imbalance occurs, namely the resistance of the NS interface, phase slip centers, and the flow of a supercurrent in the presence of a temperature gradient.

  9. Spectroelectrochemical evidence for the effect of phase structure and interface on charge behavior in poly(3-hexylthiophene): Fullerene active layer

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Rong, E-mail: [Research Institute for New Materials Technology, Chongqing University of Arts and Sciences, Chongqing 402160 (China); Ni, Haitao, E-mail: [College of Materials and Chemical Engineering, Chongqing University of Arts and Sciences, Chongqing 402160 (China); Wang, Zhaodong, E-mail: [College of Materials and Chemical Engineering, Chongqing University of Arts and Sciences, Chongqing 402160 (China); Liu, Yurong, E-mail: [Research Institute for New Materials Technology, Chongqing University of Arts and Sciences, Chongqing 402160 (China); Liu, Hongdong, E-mail: [Research Institute for New Materials Technology, Chongqing University of Arts and Sciences, Chongqing 402160 (China); Yang, Xin, E-mail: [Research Institute for New Materials Technology, Chongqing University of Arts and Sciences, Chongqing 402160 (China); Cheng, Jiang, E-mail: [Research Institute for New Materials Technology, Chongqing University of Arts and Sciences, Chongqing 402160 (China)


    Highlights: • The steady-state absorption spectra of P3HT{sup ·+}, P3HT{sup ·−}, PCBM{sup +} and PCBM{sup −} were obtained. • The effect of morphology of active layer on charge generation was identified. • Non-equilibrium transport of electron and hole was confirmed in PSCs. - Abstract: To investigate the correlation between morphology of active layer and performance of polymer solar cells (PSCs). Poly(3-hexylthiophene):[6,6]-phenyl-C{sub 61}-butyric acid methyl ester (P3HT:PCBM) were selected as research object and five PSCs based on active layers with varied morphology were fabricated. The results showed that P3HT crystalline phase and donor-acceptor (D-A) interface had an important influence on PSCs performance, which was revealed by structure characterization and J-V measurement. To further understanding the effect of phase structure and D-A interface on charge behavior. Spectroelectrochemistry measurement (SEC) was performed to characterize the steady-state optical absorption of P3HT, PCBM cation and anion in varied active layers, and the spectra difference of cations and anions was analyzed. The results were found that D-A interface could promote charge generation. P3HT crystalline phase and PCBM aggregation phase were beneficial for improving the charge transport ability. Meanwhile, the non-equilibrium transport of electron and hole in PSCs was corroborated by SEC.

  10. Exploring the effect of hole localization on the charge-phonon dynamics of hole doped delafossite. (United States)

    Mazumder, Nilesh; Mandal, Prasanta; Roy, Rajarshi; Ghorai, Uttam Kumar; Saha, Subhajit; Chattopadhyay, Kalyan Kumar


    For weak or moderate doping, electrical measurement is not suitable for detecting changes in the charge localization inside a semiconductor. Here, to investigate the nature of charge-phonon coupling in the presence of gradually delocalized holes within a weak doping regime (~1016 cm-3), we examine the temperature dependent Raman spectra (303-817 K) of prototype hole doped delafossite [Formula: see text] (x  =  0/0.03, y  =  0/0.01). For both [Formula: see text] and [Formula: see text] phonons, negative lineshape asymmetry and relative thermal hardening are distinctly observed upon [Formula: see text] and [Formula: see text] doping. Using Allen formalism, charge density of states at the Fermi level per spin and molecule, and charge delocalization associated to [Formula: see text] plane, are estimated to increase appreciably upon codoping compared to the [Formula: see text]-axis. We delineate the interdependence between charge-phonon coupling constant ([Formula: see text]) and anharmonic phonon lifetime ([Formula: see text]), and deduce that excitation of delocalized holes weakly coupled with phonons of larger [Formula: see text] is the governing feature of observed Fano asymmetry ([Formula: see text]) reversal.

  11. Secondary Electron Emission From Solar Cell Coverslides And Its Effect On Absolute Vehicle Charging (United States)

    Ferguson, Dale C.


    It has often been stated that earthed conductive solar cell coverslides are the best way to prevent electrostatic discharges on space solar arrays in GEO. While it is true that such coverslides will prevent differential charging on the solar arrays, it will be shown through NASCAP- 2k simulations that the secondary electron emission of such coverslides is very important for absolute vehicle charging. In particular, carbon nanotube coatings, due to the extremely low secondary electron emission from carbon, may exacerbate absolute vehicle charging. However, if they are earthed, because of their conductivity they may minimize differential charging and the possibility of arcing elsewhere on the spacecraft. Such results may also be true for insulative coverslides if spacecraft thermal blankets are made of materials with high secondary electron emission. Finally, photoemission from coverslides is investigated, with regard to anti-reflection coatings. Surfaces which reflect UV can have low photoemission, while those that absorb may have higher photoemission rates. Thus, anti-reflection coatings may lead to higher absolute spacecraft charging rates. NASCAP-2k simulations will be used to investigate these dependences for realistic spacecraft.

  12. Induced Charge Capacitive Deionization

    CERN Document Server

    Rubin, S; Biesheuvel, P M; Bercovici, M


    We demonstrate the phenomenon of induced-charge capacitive deionization (ICCDI) that occurs around a porous and conducting particle immersed in an electrolyte, under the action of an external electrostatic field. The external electric field induces an electric dipole in the porous particle, leading to capacitive charging of its volume by both cations and anions at opposite poles. This regime is characterized both by a large RC charging time and a small electrochemical charge relaxation time, which leads to rapid and significant deionization of ionic species from a volume which is on the scale of the particle. We show by theory and experiment that the transient response around a cylindrical particle results in spatially non-uniform charging and non-steady growth of depletion regions which emerge around the particle's poles. Potentially, ICCDI can be useful in applications where fast concentration changes of ionic species are required over large volumes.

  13. Internal Charging (United States)

    Minow, Joseph I.


    (1) High energy (>100keV) electrons penetrate spacecraft walls and accumulate in dielectrics or isolated conductors; (2) Threat environment is energetic electrons with sufficient flux to charge circuit boards, cable insulation, and ungrounded metal faster than charge can dissipate; (3) Accumulating charge density generates electric fields in excess of material breakdown strenght resulting in electrostatic discharge; and (4) System impact is material damage, discharge currents inside of spacecraft Faraday cage on or near critical circuitry, and RF noise.

  14. Mechanistic insights into the photoinduced charge carrier dynamics of BiOBr/CdS nanosheet heterojunctions for photovoltaic application. (United States)

    Jia, Huimin; Zhang, Beibei; He, Weiwei; Xiang, Yong; Zheng, Zhi


    The rational design of high performance hetero-structure photovoltaic devices requires a full understanding of the photoinduced charge transfer mechanism and kinetics at the interface of heterojunctions. In this paper, we intelligently fabricated p-BiOBr/n-CdS heterojunctions with perfect nanosheet arrays by using a facile successive ionic layer adsorption and reaction and chemical bath deposition methods at low temperature. A BiOBr/CdS heterojunction based solar cell has been fabricated which exhibited enhanced photovoltaic responses. Assisted by the surface photovoltage (SPV), transient photovoltage (TPV) and Kelvin probe technique, the photoinduced charge transfer dynamics on the BiOBr nanosheet and p-BiOBr/n-CdS interface were systematically investigated. It was found that the BiOBr/CdS nanosheet array heterojunctions were more efficient in facilitating charge carrier separation than both bare BiOBr and CdS films. The mechanism underlying the photoinduced charge carrier transfer behaviour was unravelled by allying the energy band of BiOBr/CdS p-n junctions from both the interfacial electric field and surface electric field. In addition, the CdS loading thickness in the p-BiOBr/n-CdS heterojunction and the incident wavelength affected greatly the transfer behavior of photoinduced charges, which was of great value for design of photovoltaic devices.

  15. Application of a finite size of the charge cloud shape generated by an X-ray photon inside the CCD

    CERN Document Server

    Tsunemi, H; Miyata, E


    A mesh experiment enables us to specify the X-ray landing position on a charge-coupled device (CCD) with subpixel resolution. By this experiment, we find that the final charge cloud shape generated by Ti-K X-ray photons (4.5 keV) in the CCD is about 1.5x1.1 mu m sup 2 (standard deviation). An X-ray photon photoabsorbed in the CCD generates a number of electrons, forming an X-ray event. It becomes up to a 4-pixel-split event since the pixel size of the CCD used (12 mu m square pixel) is bigger than the charge cloud size. Using the mesh experiment, we can determine the X-ray landing position on the CCD. In this way, we can compare the estimated X-ray landing position with the actual landing position on the CCD. Employing the charge cloud shape, we can improve the position resolution of the X-ray CCD by referring to the X-ray event pattern. We find that the position accuracy of our method is about 1.0 mu m. We discuss our method, comparing it with the charge centroid method.

  16. Computer modeling of beam space charge effects in cyclotron injector into JINR phasotron

    CERN Document Server

    Kalinichenko, V V


    Charge particle beam dynamics including space charge by direct Coulomb particle-to-particle method was simulated. For this purpose in MATLAB a new code KASKADS was developed. Numerical simulations of the particle motion confirm that it is possible to achieve separated orbits in a 5 MeV, 30 mA separated sector cyclotron (accelerating voltage varies depending on radius from 150 kV in the centre to 240 kV in the extraction region). The aperture of the accelerator must be greater than 3 cm.

  17. Interplay of electronic and geometry shell effects in properties of neutral and charged Sr clusters

    DEFF Research Database (Denmark)

    Lyalin, Andrey; Solov'yov, Ilia; Solov'yov, Andrey V.


    charged strontium clusters consisting of up to 14 atoms, average bonding distances, electronic shell closures, binding energies per atom, the gap between the highest occupied and the lowest unoccupied molecular orbitals, and spectra of the density of electronic states (DOS). It is demonstrated....... It is shown that the excessive charge essentially affects the optimized geometry of strontium clusters. Ionization of small strontium clusters results in the alteration of the magic numbers. The strong dependence of the DOS spectra on details of ionic structure allows one to perform a reliable geometry...

  18. Relativistic Klein-Gordon charge effects by information-theoretic measures

    Energy Technology Data Exchange (ETDEWEB)

    Manzano, D; Yanez, R J; Dehesa, J S [Instituto Carlos I de Fisica Teorica y Computacional, Universidad de Granada, 18071 Granada (Spain)], E-mail:, E-mail:, E-mail:


    The charge spreading of the ground and excited states of Klein-Gordon particles moving in a Coulomb potential is quantitatively analysed by means of ordinary moments and the Heisenberg measure as well as by using the most relevant information-theoretic measures of global (Shannon entropic power) and local (Fisher information) types. The dependence of these complementary quantities on the nuclear charge Z and the quantum numbers characterizing the physical states is carefully discussed. The comparison of relativistic Klein-Gordon and non-relativistic Schroedinger values is made. Non-relativistic limits at large principal quantum number n and for small values of Z are also reached.

  19. Accelerators for charged particle therapy (United States)

    Flanz, Jacob


    History has shown that energetic particles can be useful for medical applications. From the time, in 1895 when Roentgen discovered X-rays, and in 1913 when Coolidge developed the vacuum X-ray tube, energetic particles have been an important tool for medicine. Development of the appropriate tool for effective and safe radiotherapy requires an in-depth understanding of the application and constraints. Various solutions are possible and choices must be analyzed on the basis of the suitability for meeting the requirements. Some of the requirements of charged particle therapy are summarized and various accelerator options are described and discussed.

  20. Implementation of a Battery Health Monitor and Vertical Lift Aircraft Testbed for the Application of an Electrochemisty-Based State of Charge Estimator (United States)

    Potteiger, Timothy R.; Eure, Kenneth W.; Levenstein, David


    Prediction methods concerning remaining charge in lithium-ion batteries that power unmanned aerial vehicles are of critical concern for the safe fulfillment of mission objectives. In recent years, lithium-ion batteries have been the power source for both fixed wing and vertical lift electric vehicles. The purpose of this document is to describe in detail the implementation of a battery health monitor for estimating the state of charge of a lithium-ion battery and a lithium-ion polymer battery that is used to power a vertical lift aircraft test-bed. It will be demonstrated that an electro-chemistry based state of charge estimator effectively tracks battery discharge characteristics and may be employed as a useful tool in monitoring battery health.