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Sample records for charge separation effect

  1. Charge exchange effect on laser isotope separation of atomic uranium

    International Nuclear Information System (INIS)

    Niki, Hideaki; Izawa, Yasukazu; Otani, Hiroyasu; Yamanaka, Chiyoe

    1982-01-01

    Uranium isotope separating experiment was performed using the two-step photoionization technique with dye laser and nitrogen laser by heating uranium metal with electron beam and producing atomic beam using generated vapour. The experimental results are described after explaining the two-step photoionization by laser, experimental apparatus, the selection of exciting wavelength and others. Enrichment factor depends largely on the spectrum purity of dye laser which is the exciting source. A large enrichment factor of 48.3 times was obtained for spectrum width 0.03A. To put the uranium isotope separation with laser into practice, the increase of uranium atomic density is considered to be necessary for improving the yield. Experimental investigation was first carried out on the charge exchange effect that seems most likely to affect the decrease of enrichment factor, and the charge exchange cross-section was determined. The charge exchange cross-section depends on the relative kinetic energy between ions and atoms. The experimental result showed that the cross-section was about 5 x 10 -13 cm 2 at 1 eV and 10 -13 cm 2 at 90 eV. These values are roughly ten times as great as those calculated in Lawrence Livermore Laboratory, and it is expected that they become the greatest factor for giving the upper limit of uranium atomic density in a process of practical application. (Wakatsuki, Y.)

  2. Plasma expansion into vacuum with charge separation effect

    International Nuclear Information System (INIS)

    Murakami, Masakatsu

    2008-01-01

    Plasma expansion into vacuum and resultant ion acceleration are studied theoretically. A new self-similar solution is found to describe free expansion of a finite plasma mass into vacuum with a full account of charge separation effects. It is argued that the normalized plasma size Λ R/λ D plays the dominant role in determining the whole ion energy spectrum and thus the maximum ion kinetic energy, where R and λ D are the plasma scale length and the Debye length, respectively. The analytical model is compared with experiments to show excellent agreement

  3. Separation of effects of oxide-trapped charge and interface-trapped charge on mobility in irradiated power MOSFETs

    International Nuclear Information System (INIS)

    Zupac, D.; Galloway, K.F.; Khosropour, P.; Anderson, S.R.; Schrimpf, R.D.

    1993-01-01

    An effective approach to separating the effects of oxide-trapped charge and interface-trapped charge on mobility degradation in irradiated MOSFETs is demonstrated. It is based on analyzing mobility data sets which have different functional relationships between the radiation-induced-oxide-trapped charge and interface-trapped charge. Separation of effects of oxide-trapped charge and interface-trapped charge is possible only if these two trapped charge components are not linearly dependent. A significant contribution of oxide-trapped charge to mobility degradation is demonstrated and quantified

  4. The effect of solvent relaxation time constants on free energy gap law for ultrafast charge recombination following photoinduced charge separation.

    Science.gov (United States)

    Mikhailova, Valentina A; Malykhin, Roman E; Ivanov, Anatoly I

    2018-05-16

    To elucidate the regularities inherent in the kinetics of ultrafast charge recombination following photoinduced charge separation in donor-acceptor dyads in solutions, the simulations of the kinetics have been performed within the stochastic multichannel point-transition model. Increasing the solvent relaxation time scales has been shown to strongly vary the dependence of the charge recombination rate constant on the free energy gap. In slow relaxing solvents the non-equilibrium charge recombination occurring in parallel with solvent relaxation is very effective so that the charge recombination terminates at the non-equilibrium stage. This results in a crucial difference between the free energy gap laws for the ultrafast charge recombination and the thermal charge transfer. For the thermal reactions the well-known Marcus bell-shaped dependence of the rate constant on the free energy gap is realized while for the ultrafast charge recombination only a descending branch is predicted in the whole area of the free energy gap exceeding 0.2 eV. From the available experimental data on the population kinetics of the second and first excited states for a series of Zn-porphyrin-imide dyads in toluene and tetrahydrofuran solutions, an effective rate constant of the charge recombination into the first excited state has been calculated. The obtained rate constant being very high is nearly invariable in the area of the charge recombination free energy gap from 0.2 to 0.6 eV that supports the theoretical prediction.

  5. In search of chiral magnetic effect: separating flow-driven background effects and quantifying anomaly-induced charge separations

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xu-Guang [Physics Department and Center for Particle Physics and Field Theory, Fudan University, Shanghai 200433 (China); Yin, Yi [Physics Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Liao, Jinfeng [Physics Department and Center for Exploration of Energy and Matter, Indiana University, 2401 N Milo B. Sampson Lane, Bloomington, IN 47408 (United States); RIKEN BNL Research Center, Bldg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2016-12-15

    We report our recent progress on the search of Chiral Magnetic Effect (CME) by developing new measurements as well as by hydrodynamic simulations of CME and background effects, with both approaches addressing the pressing issue of separating flow-driven background contributions and possible CME signal in current heavy ion collision measurements.

  6. Studies on the Effect of Radio Frequency Field in a Cusp-Type Charge Separation Device for Direct Energy Conversion

    OpenAIRE

    HAMABE, Masaki; IZAWA, Hiroaki; TAKENO, Hiromasa; NAKAMOTO, Satoshi; ICHIMURA, Kazuya; NAKASHIMA, Yousuke

    2016-01-01

    In D-3He fusion power generation, an application of direct energy conversion is expected in which separation of charged particles is necessary. A cusp-type direct energy converter (CuspDEC) was proposed as a charge separation device, but its performance was degraded for a high density plasma. The goal of the present study is to establish an additional method to assist charge separation by using a nonlinear effect of a radio frequency (rf) electric field. Following to the previous study, we ex...

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

    Directory of Open Access Journals (Sweden)

    Satoshi Ohmura

    2016-01-01

    Full Text Available 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–C60 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+ and A- 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ohmura, Satoshi, E-mail: s.ohmura.m4@cc.it-hiroshima.ac.jp [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)

    2016-01-15

    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.

  9. Studies on the effect of radio frequency field in a cusp-type charge separation device for direct energy conversion

    International Nuclear Information System (INIS)

    Hamabe, Masaki; Izawa, Hiroaki; Takeno, Hiromasa; Nakamoto, Satoshi; Ichimura, Kazuya; Nakashima, Yousuke

    2016-01-01

    In D- 3 He fusion power generation, an application of direct energy conversion is expected in which separation of charged particles is necessary. A cusp-type direct energy converter (CuspDEC) was proposed as a charge separation device, but its performance was degraded for a high density plasma. The goal of the present study is to establish an additional method to assist charge separation by using a nonlinear effect of a radio frequency (rf) electric field. Following to the previous study, we experimentally examine the effect of an rf field to electron motion in a CuspDEC device. Two ring electrodes were newly installed in a CuspDEC simulator and the current flowing into the electron collector located in the line cusp region was measured on an rf field application. The significant variation in the current was found, and an improvement of the charge separation can be expected by using the phenomenon appropriately. (author)

  10. Effective charge separation in BiOI/Cu2O composites with enhanced photocatalytic activity

    Science.gov (United States)

    Xia, Yongmei; He, Zuming; Yang, Wei; Tang, Bin; Lu, Yalin; Hu, Kejun; Su, Jiangbin; Li, Xiaoping

    2018-02-01

    Novel BiOI/Cu2O composites were designed and synthesized for the first time by coupling reduction method at low temperature. The samples were characterized by XRD, XPS, SEM, EDS, HRTEM, UV-vis (DRS), FTIR and photo-electro-chemical (PEC) analysis. Results showed that the BiOI/Cu2O composites consisted of three-dimensional (3D), hierarchical cauliflower-like structure composed of BiOI nanosheet and Cu2O cubic submicrometer structure, the composite absorption band broadened, and the absorption intensity in the visible region strengthened. And the composites exhibited an excellent photocatalytic performance, which might be attributed to the improvement of the composite absorption and effective charge separation in BiOI/Cu2O composites. In addition, the possible photocatalytic mechanism was proposed.

  11. Multi-frequency inversion-charge pumping for charge separation and mobility analysis in high-k/InGaAs metal-oxide-semiconductor field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Djara, V.; Cherkaoui, K.; Negara, M. A.; Hurley, P. K., E-mail: paul.hurley@tyndall.ie [Tyndall National Institute, University College Cork, Dyke Parade, Cork (Ireland)

    2015-11-28

    An alternative multi-frequency inversion-charge pumping (MFICP) technique was developed to directly separate the inversion charge density (N{sub inv}) from the trapped charge density in high-k/InGaAs metal-oxide-semiconductor field-effect transistors (MOSFETs). This approach relies on the fitting of the frequency response of border traps, obtained from inversion-charge pumping measurements performed over a wide range of frequencies at room temperature on a single MOSFET, using a modified charge trapping model. The obtained model yielded the capture time constant and density of border traps located at energy levels aligned with the InGaAs conduction band. Moreover, the combination of MFICP and pulsed I{sub d}-V{sub g} measurements enabled an accurate effective mobility vs N{sub inv} extraction and analysis. The data obtained using the MFICP approach are consistent with the most recent reports on high-k/InGaAs.

  12. Physical stage of photosynthesis charge separation

    Science.gov (United States)

    Yakovlev, A. G.; Shuvalov, V. A.

    2016-06-01

    An analytical review is given concerning the biophysical aspects of light-driven primary charge separation in photosynthesis reaction centers (RCs) which are special pigment-protein complexes residing in a cell membrane. The primary (physical) stage of charge separation occurs in the pico- and femtosecond ranges and consists of transferring an electron along the active A-branch of pigments. The review presents vast factual material on both the general issues of primary photosynthesis and some more specific topics, including (1) the role of the inactive B-branch of pigments, (2) the effect of the protein environment on the charge separation, and (3) the participation of monomeric bacteriochlorophyll BA in primary electron acceptance. It is shown that the electron transfer and stabilization are strongly influenced by crystallographic water and tyrosine M210 molecules from the nearest environment of BA. A linkage between collective nuclear motions and electron transfer upon charge separation is demonstrated. The nature of the high quantum efficiency of primary charge separation reactions is discussed.

  13. Role of centrifugal and charge effects of the mass separation in a plasma centrifuge with crossed fields

    International Nuclear Information System (INIS)

    Zhdanov, V.M.; Karchevskii, A.I.; Lukovnikov, A.I.; Potanin, E.P.

    1982-01-01

    The coefficients of mass separation have been calculated for gas mixtures in crossed electric and magnetic fields. The initial kinetic equations have been derived, and the contribution of centrifugal and charge separation mechanisms to mass separation in a weakly ionized plasma has been assessed

  14. Charge separation in branched TiO_2 nanorod array homojunction aroused by quantum effect for enhanced photocatalytic decomposition of gaseous benzene

    International Nuclear Information System (INIS)

    Wang, Xiaoxia; Ni, Qian; Zeng, Dawen; Liao, Guanglan; Xie, Changsheng

    2016-01-01

    Highlights: • Charge separation in homojunction based on the broadened band gap by quantum effect. • Absolute charge separation by the passivation effect of TiO_2 nanorod. • Long-distance electron transfer behavior in photocatalysis. • Roughed surface for enhanced light harvesting by light trapping effect. - Abstract: As known, the electron transfer behavior in photocatalysis is short-distance transportation, which leads the photo-induced electrons and holes to be localized. The temporarily separated electrons and holes will recombine with each other in the localized region. In this paper, we successfully achieved electron transfer in a homojunction of branched rutile TiO_2 nanorod @nanoparticle core-shell architecture by quantum confinement effect aroused by the nanoparticle, which is proved by the blue-shifting in UV–vis absorption spectrum of the homojunction. Meanwhile, an absolute charge separation is also achieved by the long-distance electron transfer along the single-crystalline rutile TiO_2 nanorod as uninterrupted high-speed electron transfer channel to FTO substrates. Based on the effective charge separation, the photocatalytic decomposition of gaseous benzene by the homojunction is significantly enhanced, yielding 10 times CO_2 than that of the nanorod array. This homojunction interfacial charge separation, aroused by quantum effect, through long-distance transfer along the single-crystalline nanorod gives us inspiration to achieve efficient charge separation with defect-less interfaces, which might can be utilized for real-time environmental abatement and energy generation simultaneously.

  15. Degree of phase separation effects on the charge transfer properties of P3HT:Graphene nanocomposites

    International Nuclear Information System (INIS)

    Bkakri, R.; Kusmartseva, O.E.; Kusmartsev, F.V.; Song, M.; Bouazizi, A.

    2015-01-01

    Graphene layers were introduced into the matrix of regioregular poly (3-hexylthiophene-2, 5-diyl) (RR-P3HT) via solution processing in the perspective of the development of organic nanocomposites with high P3HT/Graphene interfaces areas for efficient charge transfer process. P3HT and graphene act as electrons donor and electrons acceptor materials, respectively. Spatial Fourier Transforms (FFT) and power spectral density (PSD) analysis of the AFM images show that the phase separation decreases with increasing the graphene weight ratio in the P3HT matrix. The Raman spectra of the P3HT:Graphene nanocomposites shows that the G-band of graphene shifts to low frequencies with progressive addition of graphene which proves that there is an interaction between the nanowires of P3HT and the graphene layers. We suggest that the shift of the G-band is due to electrons transfer from P3HT to graphene. The quenching of the photoluminescence (PL) intensity of P3HT with addition of graphene proves also that an electrons transfer process occurred at the P3HT/Graphene interfaces. - Highlights: • Graphene layers are elaborated from expandable graphite oxide. • The effects of the graphene doping level on the charge transfer process were studied. • The phase separation process decreases with increasing the graphene content in the P3HT matrix. • Quenching of the PL intensity is due to electrons transfer from P3HT to graphene

  16. Quantum modeling of ultrafast photoinduced charge separation

    Science.gov (United States)

    Rozzi, Carlo Andrea; Troiani, Filippo; Tavernelli, Ivano

    2018-01-01

    Phenomena involving electron transfer are ubiquitous in nature, photosynthesis and enzymes or protein activity being prominent examples. Their deep understanding thus represents a mandatory scientific goal. Moreover, controlling the separation of photogenerated charges is a crucial prerequisite in many applicative contexts, including quantum electronics, photo-electrochemical water splitting, photocatalytic dye degradation, and energy conversion. In particular, photoinduced charge separation is the pivotal step driving the storage of sun light into electrical or chemical energy. If properly mastered, these processes may also allow us to achieve a better command of information storage at the nanoscale, as required for the development of molecular electronics, optical switching, or quantum technologies, amongst others. In this Topical Review we survey recent progress in the understanding of ultrafast charge separation from photoexcited states. We report the state-of-the-art of the observation and theoretical description of charge separation phenomena in the ultrafast regime mainly focusing on molecular- and nano-sized solar energy conversion systems. In particular, we examine different proposed mechanisms driving ultrafast charge dynamics, with particular regard to the role of quantum coherence and electron-nuclear coupling, and link experimental observations to theoretical approaches based either on model Hamiltonians or on first principles simulations.

  17. Charge and spin separation in one-dimensional systems

    International Nuclear Information System (INIS)

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

    1995-01-01

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

  18. Charge separation in branched TiO{sub 2} nanorod array homojunction aroused by quantum effect for enhanced photocatalytic decomposition of gaseous benzene

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaoxia [State Key Laboratory of Materials and Processing Die & Mould Technology, Nanomaterials and Smart Sensors Research Laboratory, Department of Materials Science and Engineering, Huazhong University of Science and Technology, No. 1037, Luoyu Road, Wuhan 430074 (China); Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Wuhan 430062 (China); Ni, Qian [State Key Laboratory of Materials and Processing Die & Mould Technology, Nanomaterials and Smart Sensors Research Laboratory, Department of Materials Science and Engineering, Huazhong University of Science and Technology, No. 1037, Luoyu Road, Wuhan 430074 (China); Zeng, Dawen, E-mail: dwzeng@mail.hust.edu.cn [State Key Laboratory of Materials and Processing Die & Mould Technology, Nanomaterials and Smart Sensors Research Laboratory, Department of Materials Science and Engineering, Huazhong University of Science and Technology, No. 1037, Luoyu Road, Wuhan 430074 (China); Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Wuhan 430062 (China); Liao, Guanglan [State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, No. 1037, Luoyu Road, Wuhan 430074 (China); Xie, Changsheng [State Key Laboratory of Materials and Processing Die & Mould Technology, Nanomaterials and Smart Sensors Research Laboratory, Department of Materials Science and Engineering, Huazhong University of Science and Technology, No. 1037, Luoyu Road, Wuhan 430074 (China)

    2016-12-15

    Highlights: • Charge separation in homojunction based on the broadened band gap by quantum effect. • Absolute charge separation by the passivation effect of TiO{sub 2} nanorod. • Long-distance electron transfer behavior in photocatalysis. • Roughed surface for enhanced light harvesting by light trapping effect. - Abstract: As known, the electron transfer behavior in photocatalysis is short-distance transportation, which leads the photo-induced electrons and holes to be localized. The temporarily separated electrons and holes will recombine with each other in the localized region. In this paper, we successfully achieved electron transfer in a homojunction of branched rutile TiO{sub 2} nanorod @nanoparticle core-shell architecture by quantum confinement effect aroused by the nanoparticle, which is proved by the blue-shifting in UV–vis absorption spectrum of the homojunction. Meanwhile, an absolute charge separation is also achieved by the long-distance electron transfer along the single-crystalline rutile TiO{sub 2} nanorod as uninterrupted high-speed electron transfer channel to FTO substrates. Based on the effective charge separation, the photocatalytic decomposition of gaseous benzene by the homojunction is significantly enhanced, yielding 10 times CO{sub 2} than that of the nanorod array. This homojunction interfacial charge separation, aroused by quantum effect, through long-distance transfer along the single-crystalline nanorod gives us inspiration to achieve efficient charge separation with defect-less interfaces, which might can be utilized for real-time environmental abatement and energy generation simultaneously.

  19. Energy storage device with large charge separation

    Science.gov (United States)

    Holme, Timothy P.; Prinz, Friedrich B.; Iancu, Andrei T.

    2018-04-03

    High density energy storage in semiconductor devices is provided. There are two main aspects of the present approach. The first aspect is to provide high density energy storage in semiconductor devices based on formation of a plasma in the semiconductor. The second aspect is to provide high density energy storage based on charge separation in a p-n junction.

  20. A more than six orders of magnitude UV-responsive organic field-effect transistor utilizing a benzothiophene semiconductor and Disperse Red 1 for enhanced charge separation.

    Science.gov (United States)

    Smithson, Chad S; Wu, Yiliang; Wigglesworth, Tony; Zhu, Shiping

    2015-01-14

    A more than six orders of magnitude UV-responsive organic field-effect transistor is developed using a benzothiophene (BTBT) semiconductor and strong donor-acceptor Disperse Red 1 as the traps to enhance charge separation. The device can be returned to its low drain current state by applying a short gate bias, and is completely reversible with excellent stability under ambient conditions. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Effect of different photoanode nanostructures on the initial charge separation and electron injection process in dye sensitized solar cells: A photophysical study with indoline dyes

    Energy Technology Data Exchange (ETDEWEB)

    Idígoras, Jesús [Nanostructured Solar Cells Group, Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, Ctra. Utrera, km 1, ES-41013 Seville (Spain); Sobuś, Jan [NanoBioMedical Centre, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland); Quantum Electronics Laboratory, Faculty of Physics, Adam Mickiewicz University in Poznań, Umultowska 85, 61-614 Poznań (Poland); Jancelewicz, Mariusz [NanoBioMedical Centre, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland); Azaceta, Eneko; Tena-Zaera, Ramon [Materials Division, IK4-CIDETEC, Parque Tecnológico de San Sebastián, Paseo Miramón 196, Donostia-San Sebastián, 20009 (Spain); Anta, Juan A. [Nanostructured Solar Cells Group, Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, Ctra. Utrera, km 1, ES-41013 Seville (Spain); Ziółek, Marcin, E-mail: marziol@amu.edu.pl [Quantum Electronics Laboratory, Faculty of Physics, Adam Mickiewicz University in Poznań, Umultowska 85, 61-614 Poznań (Poland)

    2016-02-15

    Ultrafast and fast charge separation processes were investigated for complete cells based on several ZnO-based photoanode nanostructures and standard TiO{sub 2} nanoparticle layers sensitized with the indoline dye coded D358. Different ZnO morphologies (nanoparticles, nanowires, mesoporous), synthesis methods (hydrothermal, gas-phase, electrodeposition in aqueous media and ionic liquid media) and coatings (ZnO–ZnO core–shell, ZnO–TiO{sub 2} core–shell) were measured by transient absorption techniques in the time scale from 100 fs to 100 μs and in the visible and near-infrared spectral range. All of ZnO cells show worse electron injection yields with respect to those with standard TiO{sub 2} material. Lower refractive index of ZnO than that of TiO{sub 2} is suggested to be an additional factor, not considered so far, that can decrease the performance of ZnO-based solar cells. Evidence of the participation of the excited charge transfer state of the dye in the charge separation process is provided here. The lifetime of this state in fully working devices extends from several ps to several tens of ps, which is much longer than the typically postulated electron injection times in all-organic dye-sensitized solar cells. The results here provided, comprising a wide variety of morphologies and preparation methods, point to the universality of the poor performance of ZnO as photoanode material with respect to standard TiO{sub 2}. - Highlights: • Wide variety of morphologies and preparation methods has been checked for ZnO cells. • All ZnO cells work worse than TiO{sub 2} ones. • Effective refractive index might be an additional factor in solar cell performance. • Excited charge transfer state of indoline dyes participates in the charge separation.

  2. Spin-Charge Separation in Finite Length Metallic Carbon Nanotubes

    KAUST Repository

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

    2017-01-01

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

  3. Study of talcum charging status in parallel plate electrostatic separator based on particle trajectory analysis

    Science.gov (United States)

    Yunxiao, CAO; Zhiqiang, WANG; Jinjun, WANG; Guofeng, LI

    2018-05-01

    Electrostatic separation has been extensively used in mineral processing, and has the potential to separate gangue minerals from raw talcum ore. As for electrostatic separation, the particle charging status is one of important influence factors. To describe the talcum particle charging status in a parallel plate electrostatic separator accurately, this paper proposes a modern images processing method. Based on the actual trajectories obtained from sequence images of particle movement and the analysis of physical forces applied on a charged particle, a numerical model is built, which could calculate the charge-to-mass ratios represented as the charging status of particle and simulate the particle trajectories. The simulated trajectories agree well with the experimental results obtained by images processing. In addition, chemical composition analysis is employed to reveal the relationship between ferrum gangue mineral content and charge-to-mass ratios. Research results show that the proposed method is effective for describing the particle charging status in electrostatic separation.

  4. Spin-charge separation in quantum wires

    International Nuclear Information System (INIS)

    Yacoby, A.

    2004-01-01

    Full Text:Using momentum resolved tunneling between two clean parallel quantum wires in a AlGaAs/GaAs heterostructure we directly measure the dispersion of the quantum many-body modes in ballistic wires and follow their dependence on Coulomb interactions by varying the electron density. We find clear signatures of three excitation modes in the data: The anti-symmetric charge mode of the coupled wire system and two spin modes. The density dependence of the anti-symmetric charge mode agrees well with Luttinger-liquid theory. As the density of electrons is lowered, the Coulomb interaction is seen to become increasingly dominant leading to excitation velocities that are up to 2.5 times faster than the bare Fermi velocity, determined experimentally from the carrier density. The symmetric charge excitation, also expected from theory, is, however, not visible in the data. The observed spin velocities are found to be 25% slower than the bare Fermi velocities and depend linearly on carrier density. The dispersions are mapped down to a critical density at which spontaneous localization is observed. Some of the experimental findings concerning this phase will be discussed

  5. Space Charge Effects

    CERN Document Server

    Ferrario, M.; Palumbo, L.

    2014-12-19

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

  6. Microscopic dynamics of charge separation at the aqueous electrochemical interface

    OpenAIRE

    Kattirtzi, John A.; Limmer, David T.; Willard, Adam P.

    2017-01-01

    We have used molecular simulation and methods of importance sampling to study the thermodynamics and kinetics of ionic charge separation at a liquid water-metal interface. We have considered this process using canonical examples of two different classes of ions: a simple alkali-halide pair, Na$^+$I$^-$, or classical ions, and the products of water autoionization, H$_3$O$^+$OH$^-$, or water ions. We find that for both ion classes, the microscopic mechanism of charge separation, including water...

  7. Adverse Effects of Excess Residual PbI2 on Photovoltaic Performance, Charge Separation, and Trap-State Properties in Mesoporous Structured Perovskite Solar Cells.

    Science.gov (United States)

    Wang, Hao-Yi; Hao, Ming-Yang; Han, Jun; Yu, Man; Qin, Yujun; Zhang, Pu; Guo, Zhi-Xin; Ai, Xi-Cheng; Zhang, Jian-Ping

    2017-03-17

    Organic-inorganic halide perovskite solar cells have rapidly come to prominence in the photovoltaic field. In this context, CH 3 NH 3 PbI 3 , as the most widely adopted active layer, has been attracting great attention. Generally, in a CH 3 NH 3 PbI 3 layer, unreacted PbI 2 inevitably coexists with the perovskite crystals, especially following a two-step fabrication process. There appears to be a consensus that an appropriate amount of unreacted PbI 2 is beneficial to the overall photovoltaic performance of a device, the only disadvantageous aspect of excess residual PbI 2 being viewed as its insulating nature. However, the further development of such perovskite-based devices requires a deeper understanding of the role of residual PbI 2 . In this work, PbI 2 -enriched and PbI 2 -controlled perovskite films, as two extreme cases, have been prepared by modulating the crystallinity of a pre-deposited PbI 2 film. The effects of excess residual PbI 2 have been elucidated on the basis of spectroscopic and optoelectronic studies. The initial charge separation, the trap-state density, and the trap-state distribution have all been found to be adversely affected in PbI 2 -enriched devices, to the detriment of photovoltaic performance. This leads to a biphasic recombination process and accelerates the charge carrier recombination dynamics. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Plasmon-induced charge separation: chemistry and wide applications.

    Science.gov (United States)

    Tatsuma, Tetsu; Nishi, Hiroyasu; Ishida, Takuya

    2017-05-01

    Recent development of nanoplasmonics has stimulated chemists to utilize plasmonic nanomaterials for efficient and distinctive photochemical applications, and physicists to boldly go inside the "wet" chemistry world. The discovery of plasmon-induced charge separation (PICS) has even accelerated these trends. On the other hand, some confusion is found in discussions about PICS. In this perspective, we focus on differences between PICS and some other phenomena such as co-catalysis effect and plasmonic nanoantenna effect. In addition, materials and nanostructures suitable for PICS are shown, and characteristics and features unique to PICS are documented. Although it is well known that PICS has been applied to photovoltaics and photocatalysis, here light is shed on other applications that take better advantage of PICS, such as chemical sensing and biosensing, various photochromisms, photoswitchable functionalities and nanoscale photofabrication.

  9. Laser-induced charge separation in organic nanofibers

    DEFF Research Database (Denmark)

    Tavares, Luciana; Behn, Dino; Kjelstrup-Hansen, Jakob

    Organic semiconductors have unique properties that can be tailored via synthetic chemistry for specific applications, which combined with their low price and straight-forward processing over large areas make them interesting materials for future devices. Certain oligomers can self-assemble into c......Organic semiconductors have unique properties that can be tailored via synthetic chemistry for specific applications, which combined with their low price and straight-forward processing over large areas make them interesting materials for future devices. Certain oligomers can self......-assemble into crystalline nanofibers by vapor deposition onto muscovite mica substrates, and we have recently shown that such nanofibers can be transferred to different substrates by roll-printing and used as the active material in e.g. organic field-effect transistors (OFETs), organic light-emitting transistors (OLETs......), and organic phototransistors (OPTs). However, several device-related issues incl. charge-separation and local band structure remain poorly understood. In this work, we use electrostatic force microscopy (EFM) combined with optical microscopy to study the local surface charge of an individual organic nanofiber...

  10. Space-Charge Effect

    International Nuclear Information System (INIS)

    Chauvin, N

    2013-01-01

    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. (author)

  11. Space-Charge Effect

    CERN Document Server

    Chauvin, N.

    2013-12-16

    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.

  12. Ultrafast photoinduced charge separation in metal-semiconductor nanohybrids.

    Science.gov (United States)

    Mongin, Denis; Shaviv, Ehud; Maioli, Paolo; Crut, Aurélien; Banin, Uri; Del Fatti, Natalia; Vallée, Fabrice

    2012-08-28

    Hybrid nano-objects formed by two or more disparate materials are among the most promising and versatile nanosystems. A key parameter in their properties is interaction between their components. In this context we have investigated ultrafast charge separation in semiconductor-metal nanohybrids using a model system of gold-tipped CdS nanorods in a matchstick architecture. Experiments are performed using an optical time-resolved pump-probe technique, exciting either the semiconductor or the metal component of the particles, and probing the light-induced change of their optical response. Electron-hole pairs photoexcited in the semiconductor part of the nanohybrids are shown to undergo rapid charge separation with the electron transferred to the metal part on a sub-20 fs time scale. This ultrafast gold charging leads to a transient red-shift and broadening of the metal surface plasmon resonance, in agreement with results for free clusters but in contrast to observation for static charging of gold nanoparticles in liquid environments. Quantitative comparison with a theoretical model is in excellent agreement with the experimental results, confirming photoexcitation of one electron-hole pair per nanohybrid followed by ultrafast charge separation. The results also point to the utilization of such metal-semiconductor nanohybrids in light-harvesting applications and in photocatalysis.

  13. Phase separation, effects of magnetic field and high pressure on charge ordering in γ-Na0.5CoO2

    International Nuclear Information System (INIS)

    Yang, H.X.; Shi, Y.G.; Nie, C.J.; Wu, D.; Yang, L.X.; Dong, C.; Yu, H.C.; Zhang, H.R.; Jin, C.Q.; Li, J.Q.

    2005-01-01

    Transmission electron microscopy (TEM) observations reveal the presence of complex superstructures and remarkable phase separation in association with Na-ordering phenomenon in γ-Na 0.5 CoO 2 . Resistivity and magnetization measurements indicate that three phase transitions at the temperatures of 25, 53 and 90 K, respectively, appear commonly in γ-Na 0.5 CoO 2 samples. Under a high pressure up to 10 kbar, the low-temperature transport properties show certain changes below the charge order transition; under an applied magnetic field of 7 T, phase transitions at around 25 and 53 K, proposed fundamentally in connection with alternations of magnetic structure and charge ordering maintain almost unchanged

  14. Spin-charge separation in ultra-cold quantum gases

    OpenAIRE

    Recati, A.; Fedichev, P. O.; Zwerger, W.; Zoller, P.

    2002-01-01

    We investigate the physical properties of quasi-1D quantum gases of fermion atoms confined in harmonic traps. Using the fact that for a homogeneous gas, the low energy properties are exactly described by a Luttinger model, we analyze the nature and manifestations of the spin-charge separation. Finally we discuss the necessary physical conditions and experimental limitations confronting possible experimental implementations.

  15. Microscopic dynamics of charge separation at the aqueous electrochemical interface.

    Science.gov (United States)

    Kattirtzi, John A; Limmer, David T; Willard, Adam P

    2017-12-19

    We have used molecular simulation and methods of importance sampling to study the thermodynamics and kinetics of ionic charge separation at a liquid water-metal interface. We have considered this process using canonical examples of two different classes of ions: a simple alkali-halide pair, Na + I - , or classical ions, and the products of water autoionization, H 3 O + OH - , or water ions. We find that for both ion classes, the microscopic mechanism of charge separation, including water's collective role in the process, is conserved between the bulk liquid and the electrode interface. However, the thermodynamic and kinetic details of the process differ between these two environments in a way that depends on ion type. In the case of the classical ion pairs, a higher free-energy barrier to charge separation and a smaller flux over that barrier at the interface result in a rate of dissociation that is 40 times slower relative to the bulk. For water ions, a slightly higher free-energy barrier is offset by a higher flux over the barrier from longer lived hydrogen-bonding patterns at the interface, resulting in a rate of association that is similar both at and away from the interface. We find that these differences in rates and stabilities of charge separation are due to the altered ability of water to solvate and reorganize in the vicinity of the metal interface.

  16. Theory and application of dual-transistor charge separation analysis

    International Nuclear Information System (INIS)

    Fleetwood, D.M.; Schwank, J.R.; Winokur, P.S.; Sexton, F.W.; Shaneyfelt, M.R.

    1989-01-01

    The authors describe a dual-transistor charge separation method to evaluate the radiation response of MOS transistors. This method requires that n- and p-channel transistors with identically processed oxides be irradiated under identical conditions at the same oxide electric fields. Combining features of single-transistor midgap and mobility methods, the authors show how one may determine threshold voltage shifts due to oxide-trapped and interface-trapped charge from standard threshold voltage and mobility measurements. These measurements can be made at currents 2-5 orders of magnitude higher than those required for midgap, subthreshold slope, and charge-pumping methods. The dual-transistor method contains no adjustable parameters, and includes an internal self-consistency check. The accuracy of the method is verified by comparison to midgap, subthreshold slope, and charge-pumping methods for several MOS processes and technologies

  17. The role of interfacial water layer in atmospherically relevant charge separation

    Science.gov (United States)

    Bhattacharyya, Indrani

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

  18. Directional Charge Separation in Isolated Organic Semiconductor Crystalline Nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, Michael; Labastide, Joelle; Bond-Thompson, Hilary; Briseno, Alejandro; Collela, Nicolas

    2017-03-01

    In the conventional view of organic photovoltaics (OPV), localized electronic excitations (excitons) formed in the active layer are transported by random 3D diffusion to an interface where charge separation and extraction take place. Because radiative de-excitation is usually strongly allowed in organic semiconductors, efficient charge separation requires high exciton mobility, with much of the diffusive motion ‘wasted’ in directions that don’t result in an interface encounter. Our research efforts are focused on ways to enforce a preferred directionality in energy and/or charge transport using ordered crystalline nanowires in which the intermolecular interactions that facilitate transport along, for example, the pi-stacking axis, can be made several orders of magnitude stronger than those in a transverse direction. The results presented in our recent work (Nature Communications) is a first step towards realizing the goal of directional control of both energy transport and charge separation, where excitons shared between adjacent molecules dissociate exclusively along the pi-stacking direction.

  19. Separation selectivity patterns of fully charged achiral compounds in capillary electrophoresis with a neutral cyclodextrin.

    Science.gov (United States)

    Soonthorntantikul, Wasura; Srisa-art, Monpichar; Leepipatpiboon, Natchanun; Nhujak, Thumnoon

    2013-01-01

    Based on the separation selectivity equation, related to the dimensionless parameters for fully charged achiral analytes using a neutral CD, the separation selectivity can be classified into seven patterns. With respect to CZE without CD, the presence of CD in the buffer may improve, or reduce, the separation selectivity with this effect being accompanied by the same or reversed electrophoretic mobility order for charged analytes. This can depend on the separation selectivity of the two analytes in free solution, the binding selectivity, the separation selectivity of analyte-CD complexes and the ratio of electrophoretic mobility of the analytes in free, and complexed forms. Using positional isomers of benzoic acids and phenoxy acids as test analytes and α-CD as a selector, the observed separation selectivity shapes were found to be in excellent agreement with the predicted separation selectivities. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Describing long-range charge-separation processes with subsystem density-functional theory

    Energy Technology Data Exchange (ETDEWEB)

    Solovyeva, Alisa; Neugebauer, Johannes, E-mail: j.neugebauer@uni-muenster.de [Theoretische Organische Chemie, Organisch-Chemisches Institut and Center for Multiscale Theory and Simulation, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster (Germany); Pavanello, Michele, E-mail: m.pavanello@rutgers.edu [Department of Chemistry, Rutgers University, 73 Warren St., Newark, New Jersey 07102 (United States)

    2014-04-28

    Long-range charge-transfer processes in extended systems are difficult to describe with quantum chemical methods. In particular, cost-effective (non-hybrid) approximations within time-dependent density functional theory (DFT) are not applicable unless special precautions are taken. Here, we show that the efficient subsystem DFT can be employed as a constrained DFT variant to describe the energetics of long-range charge-separation processes. A formal analysis of the energy components in subsystem DFT for such excitation energies is presented, which demonstrates that both the distance dependence and the long-range limit are correctly described. In addition, electronic couplings for these processes as needed for rate constants in Marcus theory can be obtained from this method. It is shown that the electronic structure of charge-separated states constructed by a positively charged subsystem interacting with a negatively charged one is difficult to converge — charge leaking from the negative subsystem to the positive one can occur. This problem is related to the delocalization error in DFT and can be overcome with asymptotically correct exchange–correlation (XC) potentials or XC potentials including a sufficiently large amount of exact exchange. We also outline an approximate way to obtain charge-transfer couplings between locally excited and charge-separated states.

  1. Describing long-range charge-separation processes with subsystem density-functional theory

    International Nuclear Information System (INIS)

    Solovyeva, Alisa; Neugebauer, Johannes; Pavanello, Michele

    2014-01-01

    Long-range charge-transfer processes in extended systems are difficult to describe with quantum chemical methods. In particular, cost-effective (non-hybrid) approximations within time-dependent density functional theory (DFT) are not applicable unless special precautions are taken. Here, we show that the efficient subsystem DFT can be employed as a constrained DFT variant to describe the energetics of long-range charge-separation processes. A formal analysis of the energy components in subsystem DFT for such excitation energies is presented, which demonstrates that both the distance dependence and the long-range limit are correctly described. In addition, electronic couplings for these processes as needed for rate constants in Marcus theory can be obtained from this method. It is shown that the electronic structure of charge-separated states constructed by a positively charged subsystem interacting with a negatively charged one is difficult to converge — charge leaking from the negative subsystem to the positive one can occur. This problem is related to the delocalization error in DFT and can be overcome with asymptotically correct exchange–correlation (XC) potentials or XC potentials including a sufficiently large amount of exact exchange. We also outline an approximate way to obtain charge-transfer couplings between locally excited and charge-separated states

  2. Tribo-charging properties of waste plastic granules in process of tribo-electrostatic separation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jia, E-mail: weee@sjtu.edu.cn; Wu, Guiqing; Xu, Zhenming

    2015-01-15

    Highlights: • The cyclone charging was more effective and stable than vibrating charging. • The small particle size was better changed than large ones and was more suitable recycled by TES. • The drying pretreatment is good for improving the short-term charging effect. - Abstract: Plastic products can be found everywhere in people’s daily life. With the consistent growth of plastic consumption, more and more plastic waste is generated. Considering the stable chemical and physics characteristics of plastic, regular waste management methods are not suitable for recycling economic strategy of each government, which has become a serious environmental problem. Recycling plastic waste is considered to be the best way to treat it, because it cannot only deduce the waste but also save the energy to produce new virgin plastic. Tribo-electrostatic separation is strongly recommended for plastic separation as it can preserve the original properties of plastic and has little additional pollution. In this study, plastic granules are generated by crushing plastic waste in waste electric and electronic equipment. The tribo-charging properties of plastic waste were studied by vibrating tribo-charging and cyclone tribo-charging. The triboelectric series obtained by vibrating was: (−)-PE–PS–PC–PVC–ABS–PP-(+), while the triboelectric series obtained by cyclone was (−)-PE–PS–PC–PVC–ABS–PP-(+). Further, the cyclone charging was more effective and stable than vibrating charging. The impact factors experiments showed that small particle size was better changed than large ones and were more suitable recycled by tribo-electrostatic separation. High relative humidity was identified as impede charging effect. The results of this study will help defining the operating parameters of subsequent separator.

  3. Tribo-charging properties of waste plastic granules in process of tribo-electrostatic separation

    International Nuclear Information System (INIS)

    Li, Jia; Wu, Guiqing; Xu, Zhenming

    2015-01-01

    Highlights: • The cyclone charging was more effective and stable than vibrating charging. • The small particle size was better changed than large ones and was more suitable recycled by TES. • The drying pretreatment is good for improving the short-term charging effect. - Abstract: Plastic products can be found everywhere in people’s daily life. With the consistent growth of plastic consumption, more and more plastic waste is generated. Considering the stable chemical and physics characteristics of plastic, regular waste management methods are not suitable for recycling economic strategy of each government, which has become a serious environmental problem. Recycling plastic waste is considered to be the best way to treat it, because it cannot only deduce the waste but also save the energy to produce new virgin plastic. Tribo-electrostatic separation is strongly recommended for plastic separation as it can preserve the original properties of plastic and has little additional pollution. In this study, plastic granules are generated by crushing plastic waste in waste electric and electronic equipment. The tribo-charging properties of plastic waste were studied by vibrating tribo-charging and cyclone tribo-charging. The triboelectric series obtained by vibrating was: (−)-PE–PS–PC–PVC–ABS–PP-(+), while the triboelectric series obtained by cyclone was (−)-PE–PS–PC–PVC–ABS–PP-(+). Further, the cyclone charging was more effective and stable than vibrating charging. The impact factors experiments showed that small particle size was better changed than large ones and were more suitable recycled by tribo-electrostatic separation. High relative humidity was identified as impede charging effect. The results of this study will help defining the operating parameters of subsequent separator

  4. Spin-Charge Separation in Finite Length Metallic Carbon Nanotubes

    KAUST Repository

    Zhang, Yongyou

    2017-10-17

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

  5. Tribo-charging properties of waste plastic granules in process of tribo-electrostatic separation.

    Science.gov (United States)

    Li, Jia; Wu, Guiqing; Xu, Zhenming

    2015-01-01

    Plastic products can be found everywhere in people's daily life. With the consistent growth of plastic consumption, more and more plastic waste is generated. Considering the stable chemical and physics characteristics of plastic, regular waste management methods are not suitable for recycling economic strategy of each government, which has become a serious environmental problem. Recycling plastic waste is considered to be the best way to treat it, because it cannot only deduce the waste but also save the energy to produce new virgin plastic. Tribo-electrostatic separation is strongly recommended for plastic separation as it can preserve the original properties of plastic and has little additional pollution. In this study, plastic granules are generated by crushing plastic waste in waste electric and electronic equipment. The tribo-charging properties of plastic waste were studied by vibrating tribo-charging and cyclone tribo-charging. The triboelectric series obtained by vibrating was: (-)-PE-PS-PC-PVC-ABS-PP-(+), while the triboelectric series obtained by cyclone was (-)-PE-PS-PC-PVC-ABS-PP-(+). Further, the cyclone charging was more effective and stable than vibrating charging. The impact factors experiments showed that small particle size was better changed than large ones and were more suitable recycled by tribo-electrostatic separation. High relative humidity was identified as impede charging effect. The results of this study will help defining the operating parameters of subsequent separator. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Energetics and kinetics of primary charge separation in bacterial photosynthesis.

    Science.gov (United States)

    LeBard, David N; Kapko, Vitaliy; Matyushov, Dmitry V

    2008-08-21

    We report the results of molecular dynamics (MD) simulations and formal modeling of the free-energy surfaces and reaction rates of primary charge separation in the reaction center of Rhodobacter sphaeroides. Two simulation protocols were used to produce MD trajectories. Standard force-field potentials were employed in the first protocol. In the second protocol, the special pair was made polarizable to reproduce a high polarizability of its photoexcited state observed by Stark spectroscopy. The charge distribution between covalent and charge-transfer states of the special pair was dynamically adjusted during the simulation run. We found from both protocols that the breadth of electrostatic fluctuations of the protein/water environment far exceeds previous estimates, resulting in about 1.6 eV reorganization energy of electron transfer in the first protocol and 2.5 eV in the second protocol. Most of these electrostatic fluctuations become dynamically frozen on the time scale of primary charge separation, resulting in much smaller solvation contributions to the activation barrier. While water dominates solvation thermodynamics on long observation times, protein emerges as the major thermal bath coupled to electron transfer on the picosecond time of the reaction. Marcus parabolas were obtained for the free-energy surfaces of electron transfer by using the first protocol, while a highly asymmetric surface was obtained in the second protocol. A nonergodic formulation of the diffusion-reaction electron-transfer kinetics has allowed us to reproduce the experimental results for both the temperature dependence of the rate and the nonexponential decay of the population of the photoexcited special pair.

  7. Space charge effects of CSR

    International Nuclear Information System (INIS)

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

    2000-01-01

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

  8. Understanding the free energy barrier and multiple timescale dynamics of charge separation in organic photovoltaic cells.

    Science.gov (United States)

    Yan, Yaming; Song, Linze; Shi, Qiang

    2018-02-28

    By employing several lattice model systems, we investigate the free energy barrier and real-time dynamics of charge separation in organic photovoltaic (OPV) cells. It is found that the combined effects of the external electric field, entropy, and charge delocalization reduce the free energy barrier significantly. The dynamic disorder reduces charge carrier delocalization and results in the increased charge separation barrier, while the effect of static disorder is more complicated. Simulation of the real-time dynamics indicates that the free charge generation process involves multiple time scales, including an ultrafast component within hundreds of femtoseconds, an intermediate component related to the relaxation of the hot charge transfer (CT) state, and a slow component on the time scale of tens of picoseconds from the thermally equilibrated CT state. Effects of hot exciton dissociation as well as its dependence on the energy offset between the Frenkel exciton and the CT state are also analyzed. The current results indicate that only a small energy offset between the band gap and the lowest energy CT state is needed to achieve efficient free charge generation in OPV devices, which agrees with recent experimental findings.

  9. Understanding the free energy barrier and multiple timescale dynamics of charge separation in organic photovoltaic cells

    Science.gov (United States)

    Yan, Yaming; Song, Linze; Shi, Qiang

    2018-02-01

    By employing several lattice model systems, we investigate the free energy barrier and real-time dynamics of charge separation in organic photovoltaic (OPV) cells. It is found that the combined effects of the external electric field, entropy, and charge delocalization reduce the free energy barrier significantly. The dynamic disorder reduces charge carrier delocalization and results in the increased charge separation barrier, while the effect of static disorder is more complicated. Simulation of the real-time dynamics indicates that the free charge generation process involves multiple time scales, including an ultrafast component within hundreds of femtoseconds, an intermediate component related to the relaxation of the hot charge transfer (CT) state, and a slow component on the time scale of tens of picoseconds from the thermally equilibrated CT state. Effects of hot exciton dissociation as well as its dependence on the energy offset between the Frenkel exciton and the CT state are also analyzed. The current results indicate that only a small energy offset between the band gap and the lowest energy CT state is needed to achieve efficient free charge generation in OPV devices, which agrees with recent experimental findings.

  10. On the role of local charge carrier mobility in the charge separation mechanism of organic photovoltaics.

    Science.gov (United States)

    Yoshikawa, Saya; Saeki, Akinori; Saito, Masahiko; Osaka, Itaru; Seki, Shu

    2015-07-21

    Although the charge separation (CS) and transport processes that compete with geminate and non-geminate recombination are commonly regarded as the governing factors of organic photovoltaic (OPV) efficiency, the details of the CS mechanism remain largely unexplored. Here we provide a systematic investigation on the role of local charge carrier mobility in bulk heterojunction films of ten different low-bandgap polymers and polythiophene analogues blended with methanofullerene (PCBM). By correlating with the OPV performances, we demonstrated that the local mobility of the blend measured by time-resolved microwave conductivity is more important for the OPV output than those of the pure polymers. Furthermore, the results revealed two separate trends for crystalline and semi-crystalline polymers. This work offers guidance in the design of high-performance organic solar cells.

  11. Charge separation at nanoscale interfaces: energy-level alignment including two-quasiparticle interactions.

    Science.gov (United States)

    Li, Huashan; Lin, Zhibin; Lusk, Mark T; Wu, Zhigang

    2014-10-21

    The universal and fundamental criteria for charge separation at interfaces involving nanoscale materials are investigated. In addition to the single-quasiparticle excitation, all the two-quasiparticle effects including exciton binding, Coulomb stabilization, and exciton transfer are considered, which play critical roles on nanoscale interfaces for optoelectronic applications. We propose a scheme allowing adding these two-quasiparticle interactions on top of the single-quasiparticle energy level alignment for determining and illuminating charge separation at nanoscale interfaces. Employing the many-body perturbation theory based on Green's functions, we quantitatively demonstrate that neglecting or simplifying these crucial two-quasiparticle interactions using less accurate methods is likely to predict qualitatively incorrect charge separation behaviors at nanoscale interfaces where quantum confinement dominates.

  12. Semiconductor nanoparticles with spatial separation of charge carriers: synthesis and optical properties

    International Nuclear Information System (INIS)

    Vasiliev, Roman B; Dirin, Dmitry N; Gaskov, Alexander M

    2011-01-01

    The results of studies on core/shell semiconductor nanoparticles with spatial separation of photoexcited charge carriers are analyzed and generalized. Peculiarities of the electronic properties of semiconductor/semiconductor heterojunctions formed inside such particles are considered. Data on the effect of spatial separation of charge carriers on the optical properties of nanoparticles including spectral shifts of the exciton bands, absorption coefficients and electron–hole pair recombination times are presented. Methods of synthesis of core/shell semiconductor nanoparticles in solutions are discussed. Specific features of the optical properties of anisotropic semiconductor nanoparticles with the semiconductor/semiconductor junctions are noted. The bibliography includes 165 references.

  13. The laser proton acceleration in the strong charge separation regime

    International Nuclear Information System (INIS)

    Nishiuchi, M.; Fukumi, A.; Daido, H.; Li, Z.; Sagisaka, A.; Ogura, K.; Orimo, S.; Kado, M.; Hayashi, Y.; Mori, M.; Bulanov, S.V.; Esirkepov, T.; Nemoto, K.; Oishi, Y.; Nayuki, T.; Fujii, T.; Noda, A.; Iwashita, Y.; Shirai, T.; Nakamura, S.

    2006-01-01

    We report the experimental results of proton acceleration as well as the simple one-dimensional model which explains our experimental data. The proton acceleration experiment is carried out with a TW short pulse laser irradiated on a tantalum thin-foil target (3 μm thickness) with an intensity of ∼3x10 18 Wcm -2 . Accelerated protons exhibit a typical energy spectrum with two quasi-Maxwellian components with a high energy cut-off. We can successfully explain the higher energy part as well as the cut off energy of the proton spectrum with the simple-one-dimensional model based on the strong charge separation regime, which is the extension of the model proposed originally by [M. Passoni et al., Phys. Rev. E 69 (2004) 026411

  14. Mixed-mode reversed phase/positively charged repulsion chromatography for intact protein separation.

    Science.gov (United States)

    Ding, Ling; Guo, Zhimou; Hu, Zhuo; Liang, Xinmiao

    2017-05-10

    A mixed-mode reversed phase/positively charged repulsion stationary phase C8PN composed of octyl and amino group has been developed for separation of intact protein. Before the separation of proteins, a set of probe compounds were employed to evaluate the chromatographic properties of C8PN, demonstrating typical reversed phase/positively charged repulsion interaction on this stationary phase as estimated. Then the new C8PN stationary phase was used to separate a standard protein mixture on the reversed phase mode. Compared with a commercial C4 stationary phase, it showed different selectivity for some proteins. In order to better understand the properties of C8PN, the effect of acetonitrile content was investigated based on retention equation. Higher values of the equation parameters on C8PN demonstrated that the protein retentions were more sensitive to the change of acetonitrile content. Besides, the influences of buffer salt additives on the protein retentions were also studied. The retention factors of the proteins got larger with the increase of buffer salt concentration, which confirmed the positively charged repulsion interaction on the column. Finally, the C8PN was further applied to separate oxidized- and reduced- forms of Recombinant Human Growth Hormone. Our study indicated the advantages and application potential of mixed-mode reversed phase/positively charged repulsion stationary phase for intact protein separation. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Motion-based, high-yielding, and fast separation of different charged organics in water.

    Science.gov (United States)

    Xuan, Mingjun; Lin, Xiankun; Shao, Jingxin; Dai, Luru; He, Qiang

    2015-01-12

    We report a self-propelled Janus silica micromotor as a motion-based analytical method for achieving fast target separation of polyelectrolyte microcapsules, enriching different charged organics with low molecular weights in water. The self-propelled Janus silica micromotor catalytically decomposes a hydrogen peroxide fuel and moves along the direction of the catalyst face at a speed of 126.3 μm s(-1) . Biotin-functionalized Janus micromotors can specifically capture and rapidly transport streptavidin-modified polyelectrolyte multilayer capsules, which could effectively enrich and separate different charged organics in water. The interior of the polyelectrolyte multilayer microcapsules were filled with a strong charged polyelectrolyte, and thus a Donnan equilibrium is favorable between the inner solution within the capsules and the bulk solution to entrap oppositely charged organics in water. The integration of these self-propelled Janus silica micromotors and polyelectrolyte multilayer capsules into a lab-on-chip device that enables the separation and analysis of charged organics could be attractive for a diverse range of applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Charged singularities: repulsive effects

    Energy Technology Data Exchange (ETDEWEB)

    De Felice, F; Nobili, L [Padua Univ. (Italy). Ist. di Fisica; Calvani, M [Padua Univ. (Italy). Ist. di Astronomia

    1980-07-01

    The repulsive phenomena which a particle experiences in the vicinity of a naked singularity are investigated in the Kerr-Newman space-time. The aim is to extend the knowledge of this fact to charged solutions and to have a direct indication of how, in these situations, the gravitational and electrostatic interactions are competing.

  17. On the Molecular Origin of Charge Separation at the Donor-Acceptor Interface

    KAUST Repository

    Sini, Gjergji; Schubert, Marcel; Risko, Chad; Roland, Steffen; Lee, Olivia P.; Chen, Zhihua; Richter, Thomas V.; Dolfen, Daniel; Coropceanu, Veaceslav; Ludwigs, Sabine; Scherf, Ullrich; Facchetti, Antonio; Frechet, Jean; Neher, Dieter

    2018-01-01

    and theoretical approach is used to understand the intimate mechanisms by which molecular structure contributes to exciton dissociation, charge separation, and charge recombination at the donor–acceptor (D–A) interface. Model systems comprised of polythiophene

  18. Charge separation sensitized by advanced II-VI semiconductor nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, David F. [Univ.of California, Merced, CA (United States)

    2017-04-11

    This proposal focuses on how the composition and morphology of pure and alloyed II-VI semiconductor heterostructures control their spectroscopic and dynamical properties. The proposed research will use a combination of synthesis development, electron microscopy, time-resolved electronic spectroscopy and modeling calculations to study these nanostructures. The proposed research will examine the extent to which morphology, compression due to lattice mismatch and alloy effects can be used to tune the electron and hole energies and the spectroscopic properties of II-VI heterojunctions. It will also use synthesis, optical spectroscopy and HRTEM to examine the role of lattice mismatch and hence lattice strain in producing interfacial defects, and the extent to which defect formation can be prevented by controlling the composition profile through the particles and across the interfaces. Finally, we will study the magnitude of the surface roughness in core/shell nanostructures and the role of shell thickness variability on the inhomogeneity of interfacial charge transfer rates.

  19. Hydrodynamics with chiral anomaly and charge separation in relativistic heavy ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Yi, E-mail: yyin@bnl.gov [Physics Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Liao, Jinfeng, E-mail: liaoji@indiana.edu [Physics Department and Center for Exploration of Energy and Matter, Indiana University, 2401 N Milo B. Sampson Lane, Bloomington, IN 47408 (United States); RIKEN BNL Research Center, Bldg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2016-05-10

    Matter with chiral fermions is microscopically described by theory with quantum anomaly and macroscopically described (at low energy) by anomalous hydrodynamics. For such systems in the presence of external magnetic field and chirality imbalance, a charge current is generated along the magnetic field direction — a phenomenon known as the Chiral Magnetic Effect (CME). The quark–gluon plasma created in relativistic heavy ion collisions provides an (approximate) example, for which the CME predicts a charge separation perpendicular to the collisional reaction plane. Charge correlation measurements designed for the search of such signal have been done at RHIC and the LHC for which the interpretations, however, remain unclear due to contamination by background effects that are collective flow driven, theoretically poorly constrained, and experimentally hard to separate. Using anomalous (and viscous) hydrodynamic simulations, we make a first attempt at quantifying contributions to observed charge correlations from both CME and background effects in one and same framework. The implications for the search of CME are discussed.

  20. Effects of Macroion Geometry and Charge Discretization in Charge Reversal

    OpenAIRE

    Mukherjee, Arup K.

    2008-01-01

    The effects of discrete macroion surface charge distribution and valences of these surface charges and counterions on charge reversal have been studied for macroions of three different geometries and compared with those of continuous surface charge distributions. The geometry of the macroion has been observed to play an important role in overcharging in these cases. The interplay of valences of discrete microions and counterions have noticeable effects on overcharging efficiency. For some val...

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

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  2. Effects of Discrete Charge Clustering in Simulations of Charged Interfaces.

    Science.gov (United States)

    Grime, John M A; Khan, Malek O

    2010-10-12

    A system of counterions between charged surfaces is investigated, with the surfaces represented by uniform charged planes and three different arrangements of discrete surface charges - an equispaced grid and two different clustered arrangements. The behaviors of a series of systems with identical net surface charge density are examined, with particular emphasis placed on the long ranged corrections via the method of "charged slabs" and the effects of the simulation cell size. Marked differences are observed in counterion distributions and the osmotic pressure dependent on the particular representation of the charged surfaces; the uniformly charged surfaces and equispaced grids of discrete charge behave in a broadly similar manner, but the clustered systems display a pronounced decrease in osmotic pressure as the simulation size is increased. The influence of the long ranged correction is shown to be minimal for all but the very smallest of system sizes.

  3. Event-shape-engineering study of charge separation in heavy-ion collisions

    Science.gov (United States)

    Wen, Fufang; Bryon, Jacob; Wen, Liwen; Wang, Gang

    2018-01-01

    Recent measurements of charge-dependent azimuthal correlations in high-energy heavy-ion collisions have indicated charge-separation signals perpendicular to the reaction plane, and have been related to the chiral magnetic effect (CME). However, the correlation signal is contaminated with the background caused by the collective motion (flow) of the collision system, and an effective approach is needed to remove the flow background from the correlation. We present a method study with simplified Monte Carlo simulations and a multi-phase transport model, and develop a scheme to reveal the true CME signal via event-shape engineering with the flow vector of the particles of interest. Supported by a grant (DE-FG02-88ER40424) from U.S. Department of Energy, Office of Nuclear Physics

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

    Science.gov (United States)

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

    2018-01-01

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

  5. Mechanism for efficient photoinduced charge separation at disordered organic heterointerfaces

    Energy Technology Data Exchange (ETDEWEB)

    Eersel, Harm van; Janssen, Rene A.J.; Kemerink, Martijn [Eindhoven University of Technology, Department of Applied Physics, Eindhoven (Netherlands)

    2012-07-10

    Despite the poor screening of the Coulomb potential in organic semiconductors, excitons can dissociate efficiently into free charges at a donor-acceptor heterojunction, leading to application in organic solar cells. A kinetic Monte Carlo model that explains this high efficiency as a two-step process is presented. Driven by the band offset between donor and acceptor, one of the carriers first hops across the interface, forming a charge transfer (CT) complex. Since the electron and hole forming the CT complex have typically not relaxed within the disorder-broadened density of states (DOS), their remaining binding energy can be overcome by further relaxation in the DOS. The model only contains parameters that are determined from independent measurements and predicts dissociation yields in excess of 90% for a prototypical heterojunction. Field, temperature, and band offset dependencies are investigated and found to be in agreement with earlier experiments. Whereas the investigated heterojunctions have substantial energy losses associated with the dissociation process, these results suggest that it is possible to reach high dissociation yields at low energy loss. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Effect of charge ordering and phase separation on the electrical and magnetoresistive properties of polycrystalline La0.4Eu0.1Ca0.5MnO3

    Science.gov (United States)

    Krichene, A.; Boujelben, W.; Mukherjee, S.; Shah, N. A.; Solanki, P. S.

    2018-03-01

    We have investigated the effect of charge ordering and phase separation on the electrical and magnetotransport properties of La0.4Eu0.1Ca0.5MnO3 polycrystalline sample. Temperature dependence of resistivity shows a metal-insulator transition at transition temperature Tρ. A hysteretic behavior is observed for zero field resistivity curves with Tρ = 128 K on cooling process and Tρ = 136 K on warming process. Zero field resistivity curves follow Zener polynomial law in the metallic phase with unusual n exponent value ∼9. Presence of resistivity minimum at low temperatures has been ascribed to the coulombic electron-electron scattering process. Resistivity modification due to the magnetic field cycling testifies the presence of the training effect. Magnetization and resistivity appear to be highly correlated. Magnetoresistive study reveals colossal values of negative magnetoresistance reaching about 75% at 132 K under only 2T applied field. Colossal values of magnetoresistance suggest the possibility of using this sample for magnetic field sensing and spintronic applications.

  7. The Impact of Donor-Acceptor Phase Separation on the Charge Carrier Dynamics in pBTTT:PCBM Photovoltaic Blends

    KAUST Repository

    Gehrig, Dominik W.

    2015-04-07

    The effect of donor–acceptor phase separation, controlled by the donor–acceptor mixing ratio, on the charge generation and recombination dynamics in pBTTT-C14:PC70BM bulk heterojunction photovoltaic blends is presented. Transient absorption (TA) spectroscopy spanning the dynamic range from pico- to microseconds in the visible and near-infrared spectral regions reveals that in a 1:1 blend exciton dissociation is ultrafast; however, charges cannot entirely escape their mutual Coulomb attraction and thus predominantly recombine geminately on a sub-ns timescale. In contrast, a polymer:fullerene mixing ratio of 1:4 facilitates the formation of spatially separated, that is free, charges and reduces substantially the fraction of geminate charge recombination, in turn leading to much more efficient photovoltaic devices. This illustrates that spatially extended donor or acceptor domains are required for the separation of charges on an ultrafast timescale (<100 fs), indicating that they are not only important for efficient charge transport and extraction, but also critically influence the initial stages of free charge carrier formation.

  8. The Impact of Donor-Acceptor Phase Separation on the Charge Carrier Dynamics in pBTTT:PCBM Photovoltaic Blends

    KAUST Repository

    Gehrig, Dominik W.; Howard, Ian A.; Sweetnam, Sean; Burke, Timothy M.; McGehee, Michael D.; Laquai, Fré dé ric

    2015-01-01

    The effect of donor–acceptor phase separation, controlled by the donor–acceptor mixing ratio, on the charge generation and recombination dynamics in pBTTT-C14:PC70BM bulk heterojunction photovoltaic blends is presented. Transient absorption (TA) spectroscopy spanning the dynamic range from pico- to microseconds in the visible and near-infrared spectral regions reveals that in a 1:1 blend exciton dissociation is ultrafast; however, charges cannot entirely escape their mutual Coulomb attraction and thus predominantly recombine geminately on a sub-ns timescale. In contrast, a polymer:fullerene mixing ratio of 1:4 facilitates the formation of spatially separated, that is free, charges and reduces substantially the fraction of geminate charge recombination, in turn leading to much more efficient photovoltaic devices. This illustrates that spatially extended donor or acceptor domains are required for the separation of charges on an ultrafast timescale (<100 fs), indicating that they are not only important for efficient charge transport and extraction, but also critically influence the initial stages of free charge carrier formation.

  9. Synthetic system mimicking the energy transfer and charge separation of natural photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Gust, D.; Moore, T.A.

    1985-05-01

    A synthetic molecular triad consisting of a porphyrin P linked to both a quinone Q and a carotenoid polyene C has been prepared as a mimic of natural photosynthesis for solar energy conversion purposes. Laser flash excitation of the porphyrin moiety yields a charge-separated state Csup(+.)-P-Qsup(-.) within 100 ps with a quantum yield of more than 0.25. This charge-separated state has a lifetime on the microsecond time scale in suitable solvents. The triad also models photosynthetic antenna function and photoprotection from singlet oxygen damge. The successful biomimicry of photosynthetic charge separation is in part the result of multistep electron transfers which rapidly separate the charges and leave the system at high potential, but with a considerable barrier to recombination.

  10. Promising Strategy To Improve Charge Separation in Organic Photovoltaics : Installing Permanent Dipoles in PCBM Analogues

    NARCIS (Netherlands)

    de Gier, Hilde D.; Jahani, Fatemeh; Broer, Ria; Hummelen, Jan C.; Havenith, Remco W. A.

    2016-01-01

    A multidisciplinary approach involving organic synthesis and theoretical chemistry was applied to investigate a promising strategy to improve charge separation in organic photovoltaics: installing permanent dipoles in fullerene derivatives. First, a PCBM analogue with a permanent dipole in the side

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  12. Effect of the source charge on charged-boson interferometry

    International Nuclear Information System (INIS)

    Shoppa, T. D.; Koonin, S. E.; Seki, R.

    2000-01-01

    We investigate quantal perturbations of the interferometric correlations of charged bosons by the Coulomb field of an instantaneous, charged source. The source charge increases the apparent source size by weakening the correlation at nonzero relative momenta. The effect is strongest for pairs with a small total momentum and is stronger for kaons than for pions of the same momenta. The low-energy data currently available are well described by this effect. A simple expression is proposed to account for the effect. (c) 2000 The American Physical Society

  13. Early bacteriopheophytin reduction in charge separation in reaction centers of Rhodobacter sphaeroides.

    Science.gov (United States)

    Zhu, Jingyi; van Stokkum, Ivo H M; Paparelli, Laura; Jones, Michael R; Groot, Marie Louise

    2013-06-04

    A question at the forefront of biophysical sciences is, to what extent do quantum effects and protein conformational changes play a role in processes such as biological sensing and energy conversion? At the heart of photosynthetic energy transduction lie processes involving ultrafast energy and electron transfers among a small number of tetrapyrrole pigments embedded in the interior of a protein. In the purple bacterial reaction center (RC), a highly efficient ultrafast charge separation takes place between a pair of bacteriochlorophylls: an accessory bacteriochlorophyll (B) and bacteriopheophytin (H). In this work, we applied ultrafast spectroscopy in the visible and near-infrared spectral region to Rhodobacter sphaeroides RCs to accurately track the timing of the electron on BA and HA via the appearance of the BA and HA anion bands. We observed an unexpectedly early rise of the HA⁻ band that challenges the accepted simple picture of stepwise electron transfer with 3 ps and 1 ps time constants. The implications for the mechanism of initial charge separation in bacterial RCs are discussed in terms of a possible adiabatic electron transfer step between BA and HA, and the effect of protein conformation on the electron transfer rate. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  14. Spin Drag and Spin-Charge Separation in Cold Fermi Gases

    International Nuclear Information System (INIS)

    Polini, Marco; Vignale, Giovanni

    2007-01-01

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

  15. Assessment on separate effect tests

    International Nuclear Information System (INIS)

    Bernard, M.; Kukita, Y.; Renault, C.

    1985-01-01

    In the general frame of Cathare assessment this operation is aimed to qualify the set of constitutive laws by reconstitution of experimental tests. The experimental tests are selected following 2 objectives: to be able to qualify separately (as far as possible) the constitutive laws, and, to cover the entire parameter range which is of interest for safety studies. This selection has led to a set of 135 separate effect tests taken from 15 experimental facilities and which can be arranged in 3 main categories: Adiabatic flow tests, without significant external heat exchange; non adiabatic flow tests, in which external heating or cooling is applied to the test section but not being driven by wall heat exchange; and, heat transfer tests, in which wall heat transfer plays the dominant role

  16. A strong steric hindrance effect on ground state, excited state, and charge separated state properties of a CuI-diimine complex captured by X-ray transient absorption spectroscopy

    DEFF Research Database (Denmark)

    Huang, J.; Mara, M.W.; Stickrath, A.B.

    2014-01-01

    of phenanthroline. The structural dynamics of the photoinduced charge transfer process in the [CuI(dppS)2]+/TiO2 hybrid is also investigated, which suggests a more restricted environment for the complex upon binding to TiO2 NPs. Moreover, the Cu-N bond length of the oxidized state of [CuI(dppS)2]+ after electron...... dynamics and structures as well as those of the charge separated state resulting from the interfacial electron injection from the MLCT state to TiO2 nanoparticles (NPs). The OTA results show the absence of the sub-picosecond component previously assigned as the time constant for flattening, while the two...... injection to TiO2 NPs shortens by 0.05 Å compared to that in the ground state. The interpretation of these observed structural changes associated with excited and charge separated states will be discussed. These results not only set an example for applying XTA in capturing the intermediate structure...

  17. Beam-energy dependence of charge separation along the magnetic field in Au+Au collisions at RHIC.

    Science.gov (United States)

    Adamczyk, L; Adkins, J K; Agakishiev, G; Aggarwal, M M; Ahammed, Z; Alekseev, I; Alford, J; Anson, C D; Aparin, A; Arkhipkin, D; Aschenauer, E C; Averichev, G S; Banerjee, A; Beavis, D R; Bellwied, R; Bhasin, A; Bhati, A K; Bhattarai, P; Bichsel, H; Bielcik, J; Bielcikova, J; Bland, L C; Bordyuzhin, I G; Borowski, W; Bouchet, J; Brandin, A V; Brovko, S G; Bültmann, S; Bunzarov, I; Burton, T P; Butterworth, J; Caines, H; Calderón de la Barca Sánchez, M; Cebra, D; Cendejas, R; Cervantes, M C; Chaloupka, P; Chang, Z; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, L; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Chwastowski, J; Codrington, M J M; Contin, G; Cramer, J G; Crawford, H J; Cui, X; Das, S; Davila Leyva, A; De Silva, L C; Debbe, R R; Dedovich, T G; Deng, J; Derevschikov, A A; Derradi de Souza, R; Dhamija, S; di Ruzza, B; Didenko, L; Dilks, C; Ding, F; Djawotho, P; Dong, X; Drachenberg, J L; Draper, J E; Du, C M; Dunkelberger, L E; Dunlop, J C; Efimov, L G; Engelage, J; Engle, K S; Eppley, G; Eun, L; Evdokimov, O; Eyser, O; Fatemi, R; Fazio, S; Fedorisin, J; Filip, P; Finch, E; Fisyak, Y; Flores, C E; Gagliardi, C A; Gangadharan, D R; Garand, D; Geurts, F; Gibson, A; Girard, M; Gliske, S; Greiner, L; Grosnick, D; Gunarathne, D S; Guo, Y; Gupta, A; Gupta, S; Guryn, W; Haag, B; Hamed, A; Han, L-X; Haque, R; Harris, J W; Heppelmann, S; Hirsch, A; Hoffmann, G W; Hofman, D J; Horvat, S; Huang, B; Huang, H Z; Huang, X; Huck, P; Humanic, T J; Igo, G; Jacobs, W W; Jang, H; Judd, E G; Kabana, S; Kalinkin, D; Kang, K; Kauder, K; Ke, H W; Keane, D; Kechechyan, A; Kesich, A; Khan, Z H; Kikola, D P; Kisel, I; Kisiel, A; Koetke, D D; Kollegger, T; Konzer, J; Koralt, I; Kotchenda, L; Kraishan, A F; Kravtsov, P; Krueger, K; Kulakov, I; Kumar, L; Kycia, R A; Lamont, M A C; Landgraf, J M; Landry, K D; Lauret, J; Lebedev, A; Lednicky, R; Lee, J H; LeVine, M J; Li, C; Li, W; Li, X; Li, X; Li, Y; Li, Z M; Lisa, M A; Liu, F; Ljubicic, T; Llope, W J; Lomnitz, M; Longacre, R S; Luo, X; Ma, G L; Ma, Y G; Madagodagettige Don, D M M D; Mahapatra, D P; Majka, R; Margetis, S; Markert, C; Masui, H; Matis, H S; McDonald, D; McShane, T S; Minaev, N G; Mioduszewski, S; Mohanty, B; Mondal, M M; Morozov, D A; Mustafa, M K; Nandi, B K; Nasim, Md; Nayak, T K; Nelson, J M; Nigmatkulov, G; Nogach, L V; Noh, S Y; Novak, J; Nurushev, S B; Odyniec, G; Ogawa, A; Oh, K; Ohlson, A; Okorokov, V; Oldag, E W; Olvitt, D L; Pachr, M; Page, B S; Pal, S K; Pan, Y X; Pandit, Y; Panebratsev, Y; Pawlak, T; Pawlik, B; Pei, H; Perkins, C; Peryt, W; Pile, P; Planinic, M; Pluta, J; Poljak, N; Porter, J; Poskanzer, A M; Pruthi, N K; Przybycien, M; Pujahari, P R; Putschke, J; Qiu, H; Quintero, A; Ramachandran, S; Raniwala, R; Raniwala, S; Ray, R L; Riley, C K; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Ross, J F; Roy, A; Ruan, L; Rusnak, J; Rusnakova, O; Sahoo, N R; Sahu, P K; Sakrejda, I; Salur, S; Sandweiss, J; Sangaline, E; Sarkar, A; Schambach, J; Scharenberg, R P; Schmah, A M; Schmidke, W B; Schmitz, N; Seger, J; Seyboth, P; Shah, N; Shahaliev, E; Shanmuganathan, P V; Shao, M; Sharma, B; Shen, W Q; Shi, S S; Shou, Q Y; Sichtermann, E P; Singaraju, R N; Skoby, M J; Smirnov, D; Smirnov, N; Solanki, D; Sorensen, P; Spinka, H M; Srivastava, B; Stanislaus, T D S; Stevens, J R; Stock, R; Strikhanov, M; Stringfellow, B; Sumbera, M; Sun, X; Sun, X M; Sun, Y; Sun, Z; Surrow, B; Svirida, D N; Symons, T J M; Szelezniak, M A; Takahashi, J; Tang, A H; Tang, Z; Tarnowsky, T; Thomas, J H; Timmins, A R; Tlusty, D; Tokarev, M; Trentalange, S; Tribble, R E; Tribedy, P; Trzeciak, B A; Tsai, O D; Turnau, J; Ullrich, T; Underwood, D G; Van Buren, G; van Nieuwenhuizen, G; Vandenbroucke, M; Vanfossen, J A; Varma, R; Vasconcelos, G M S; Vasiliev, A N; Vertesi, R; Videbæk, F; Viyogi, Y P; Vokal, S; Voloshin, S A; Vossen, A; Wada, M; Wang, F; Wang, G; Wang, H; Wang, J S; Wang, X L; Wang, Y; Wang, Y; Webb, G; Webb, J C; Westfall, G D; Wieman, H; Wissink, S W; Witt, R; Wu, Y F; Xiao, Z; Xie, W; Xin, K; Xu, H; Xu, J; Xu, N; Xu, Q H; Xu, Y; Xu, Z; Yan, W; Yang, C; Yang, Y; Yang, Y; Ye, Z; Yepes, P; Yi, L; Yip, K; Yoo, I-K; Yu, N; Zawisza, Y; Zbroszczyk, H; Zha, W; Zhang, J B; Zhang, J L; Zhang, S; Zhang, X P; Zhang, Y; Zhang, Z P; Zhao, F; Zhao, J; Zhong, C; Zhu, X; Zhu, Y H; Zoulkarneeva, Y; Zyzak, M

    2014-08-01

    Local parity-odd domains are theorized to form inside a quark-gluon plasma which has been produced in high-energy heavy-ion collisions. The local parity-odd domains manifest themselves as charge separation along the magnetic field axis via the chiral magnetic effect. The experimental observation of charge separation has previously been reported for heavy-ion collisions at the top RHIC energies. In this Letter, we present the results of the beam-energy dependence of the charge correlations in Au+Au collisions at midrapidity for center-of-mass energies of 7.7, 11.5, 19.6, 27, 39, and 62.4 GeV from the STAR experiment. After background subtraction, the signal gradually reduces with decreased beam energy and tends to vanish by 7.7 GeV. This implies the dominance of hadronic interactions over partonic ones at lower collision energies.

  18. Beam-Energy Dependence of Charge Separation along the Magnetic Field in Au +Au Collisions at RHIC

    Science.gov (United States)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Anson, C. D.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Banerjee, A.; Beavis, D. R.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Borowski, W.; Bouchet, J.; Brandin, A. V.; Brovko, S. G.; Bültmann, S.; Bunzarov, I.; Burton, T. P.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, L.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Chwastowski, J.; Codrington, M. J. M.; Contin, G.; Cramer, J. G.; Crawford, H. J.; Cui, X.; Das, S.; Davila Leyva, A.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; Derradi de Souza, R.; Dhamija, S.; di Ruzza, B.; Didenko, L.; Dilks, C.; Ding, F.; Djawotho, P.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Engle, K. S.; Eppley, G.; Eun, L.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Fedorisin, J.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Gagliardi, C. A.; Gangadharan, D. R.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Gliske, S.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Haag, B.; Hamed, A.; Han, L.-X.; Haque, R.; Harris, J. W.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, B.; Huang, H. Z.; Huang, X.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Kesich, A.; Khan, Z. H.; Kikola, D. P.; Kisel, I.; Kisiel, A.; Koetke, D. D.; Kollegger, T.; Konzer, J.; Koralt, I.; Kotchenda, L.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulakov, I.; Kumar, L.; Kycia, R. A.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; LeVine, M. J.; Li, C.; Li, W.; Li, X.; Li, X.; Li, Y.; Li, Z. M.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, G. L.; Ma, Y. G.; Madagodagettige Don, D. M. M. D.; Mahapatra, D. P.; Majka, R.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; McShane, T. S.; Minaev, N. G.; Mioduszewski, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nigmatkulov, G.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Ohlson, A.; Okorokov, V.; Oldag, E. W.; Olvitt, D. L.; Pachr, M.; Page, B. S.; Pal, S. K.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Pawlik, B.; Pei, H.; Perkins, C.; Peryt, W.; Pile, P.; Planinic, M.; Pluta, J.; Poljak, N.; Porter, J.; Poskanzer, A. M.; Pruthi, N. K.; Przybycien, M.; Pujahari, P. R.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Riley, C. K.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Ross, J. F.; Roy, A.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sangaline, E.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, B.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Singaraju, R. N.; Skoby, M. J.; Smirnov, D.; Smirnov, N.; Solanki, D.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stevens, J. R.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Sun, X.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Svirida, D. N.; Symons, T. J. M.; Szelezniak, M. A.; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Trzeciak, B. A.; Tsai, O. D.; Turnau, J.; Ullrich, T.; Underwood, D. G.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Vanfossen, J. A.; Varma, R.; Vasconcelos, G. M. S.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wada, M.; Wang, F.; Wang, G.; Wang, H.; Wang, J. S.; Wang, X. L.; Wang, Y.; Wang, Y.; Webb, G.; Webb, J. C.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y. F.; Xiao, Z.; Xie, W.; Xin, K.; Xu, H.; Xu, J.; Xu, N.; Xu, Q. H.; Xu, Y.; Xu, Z.; Yan, W.; Yang, C.; Yang, Y.; Yang, Y.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zawisza, Y.; Zbroszczyk, H.; Zha, W.; Zhang, J. B.; Zhang, J. L.; Zhang, S.; Zhang, X. P.; Zhang, Y.; Zhang, Z. P.; Zhao, F.; Zhao, J.; Zhong, C.; Zhu, X.; Zhu, Y. H.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration

    2014-08-01

    Local parity-odd domains are theorized to form inside a quark-gluon plasma which has been produced in high-energy heavy-ion collisions. The local parity-odd domains manifest themselves as charge separation along the magnetic field axis via the chiral magnetic effect. The experimental observation of charge separation has previously been reported for heavy-ion collisions at the top RHIC energies. In this Letter, we present the results of the beam-energy dependence of the charge correlations in Au +Au collisions at midrapidity for center-of-mass energies of 7.7, 11.5, 19.6, 27, 39, and 62.4 GeV from the STAR experiment. After background subtraction, the signal gradually reduces with decreased beam energy and tends to vanish by 7.7 GeV. This implies the dominance of hadronic interactions over partonic ones at lower collision energies.

  19. Charge separation technique for metal-oxide-silicon capacitors in the presence of hydrogen deactivated dopants

    International Nuclear Information System (INIS)

    Witczak, Steven C.; Winokur, Peter S.; Lacoe, Ronald C.; Mayer, Donald C.

    2000-01-01

    An improved charge separation technique for metal-oxide-silicon (MOS) capacitors is presented which accounts for the deactivation of substrate dopants by hydrogen at elevated irradiation temperatures or small irradiation biases. Using high-frequency capacitance-voltage (C-V) measurements, radiation-induced inversion voltage shifts are separated into components due to oxide trapped charge, interface traps and deactivated dopants, where the latter is computed from a reduction in Si capacitance. In the limit of no radiation-induced dopant deactivation, this approach reduces to the standard midgap charge separation technique used widely for the analysis of room-temperature irradiations. The technique is demonstrated on a p-type MOS capacitor irradiated with 60 Co γ-rays at 100 C and zero bias, where the dopant deactivation is significant

  20. Interfacial charge separation and photovoltaic efficiency in Fe(ii)-carbene sensitized solar cells.

    Science.gov (United States)

    Pastore, Mariachiara; Duchanois, Thibaut; Liu, Li; Monari, Antonio; Assfeld, Xavier; Haacke, Stefan; Gros, Philippe C

    2016-10-12

    The first combined theoretical and photovoltaic characterization of both homoleptic and heteroleptic Fe(ii)-carbene sensitized photoanodes in working dye sensitized solar cells (DSSCs) has been performed. Three new heteroleptic Fe(ii)-NHC dye sensitizers have been synthesized, characterized and tested. Despite an improved interfacial charge separation in comparison to the homoleptic compounds, the heteroleptic complexes did not show boosted photovoltaic performances. The ab initio quantitative analysis of the interfacial electron and hole transfers and the measured photovoltaic data clearly evidenced fast recombination reactions for heteroleptics, even associated with un unfavorable directional electron flow, and hence slower injection rates, in the case of homoleptics. Notably, quantum mechanics calculations revealed that deprotonation of the not anchored carboxylic function in the homoleptic complex can effectively accelerate the electron injection rate and completely suppress the electron recombination to the oxidized dye. This result suggests that introduction of strong electron-donating substituents on the not-anchored carbene ligand in heteroleptic complexes, in such a way of mimicking the electronic effects of the carboxylate functionality, should yield markedly improved interfacial charge generation properties. The present results, providing for the first time a detailed understanding of the interfacial electron transfers and photovoltaic characterization in Fe(ii)-carbene sensitized solar cells, open the way to a rational molecular engineering of efficient iron-based dyes for photoelectrochemical applications.

  1. Charge separation and transfer in hybrid type II tunneling structures of CdTe and CdSe nanocrystals

    International Nuclear Information System (INIS)

    Gross, Dieter Konrad Michael

    2013-01-01

    Closely packed nanocrystal systems have been investigated in this thesis with respect to charge separation by charge carrier tunneling. Clustered and layered samples have been analyzed using PL-measurements and SPV-methods. The most important findings are reviewed in the following. A short outlook is also provided for potential further aspects and application of the presented results. The main purpose of this thesis was to find and quantify electronic tunneling transfer in closely packed self-assembled nanocrystal structures presenting quantum mechanical barriers of about 1 nm width. We successfully used hybrid assemblies of CdTe and CdSe nanocrystals where the expected type II alignment between CdTe and CdSe typically leads to a concentration of electrons in CdSe and holes in CdTe nanocrystals. We were able to prove the charge selectivity of the CdTe-CdSe nanocrystal interface which induces charge separation. We mainly investigated the effects related to the electron transfer from CdTe to CdSe nanocrystals. Closely packing was achieved by two independent methods: the disordered colloidal clustering in solution and the layered assembly on dry glass substrates. Both methods lead to an inter-particle distance of about 1 nm of mainly organic material which acts as a tunneling barrier. PL-spectroscopy was applied. The PL-quenching of the CdTe nanocrystals in hybrid assemblies indicates charge separation by electron transfer from CdTe to CdSe nanocrystals. A maximum quenching rate of up to 1/100 ps was measured leading to a significant global PL-quenching of up to about 70 % for the CdTe nanocrystals. It was shown that charge separation dynamics compete with energy transfer dynamics and that charge separation typically dominates. The quantum confinement effect was used to tune the energetic offset between the CdTe and CdSe nanocrystals. We thus observe a correlation of PL-quenching and offset of the energy states for the electron transfer. The investigated PL

  2. Charge separation and transfer in hybrid type II tunneling structures of CdTe and CdSe nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Gross, Dieter Konrad Michael

    2013-11-08

    Closely packed nanocrystal systems have been investigated in this thesis with respect to charge separation by charge carrier tunneling. Clustered and layered samples have been analyzed using PL-measurements and SPV-methods. The most important findings are reviewed in the following. A short outlook is also provided for potential further aspects and application of the presented results. The main purpose of this thesis was to find and quantify electronic tunneling transfer in closely packed self-assembled nanocrystal structures presenting quantum mechanical barriers of about 1 nm width. We successfully used hybrid assemblies of CdTe and CdSe nanocrystals where the expected type II alignment between CdTe and CdSe typically leads to a concentration of electrons in CdSe and holes in CdTe nanocrystals. We were able to prove the charge selectivity of the CdTe-CdSe nanocrystal interface which induces charge separation. We mainly investigated the effects related to the electron transfer from CdTe to CdSe nanocrystals. Closely packing was achieved by two independent methods: the disordered colloidal clustering in solution and the layered assembly on dry glass substrates. Both methods lead to an inter-particle distance of about 1 nm of mainly organic material which acts as a tunneling barrier. PL-spectroscopy was applied. The PL-quenching of the CdTe nanocrystals in hybrid assemblies indicates charge separation by electron transfer from CdTe to CdSe nanocrystals. A maximum quenching rate of up to 1/100 ps was measured leading to a significant global PL-quenching of up to about 70 % for the CdTe nanocrystals. It was shown that charge separation dynamics compete with energy transfer dynamics and that charge separation typically dominates. The quantum confinement effect was used to tune the energetic offset between the CdTe and CdSe nanocrystals. We thus observe a correlation of PL-quenching and offset of the energy states for the electron transfer. The investigated PL

  3. Photoinduced charge separation at polymer-fullerene interfaces of BHJ solar cells (Conference Presentation)

    Science.gov (United States)

    Poluektov, Oleg G.; Niklas, Jens; Mardis, Kristy

    2016-09-01

    While photovoltaic cells are highly promising man-made devices for direct solar energy utilization, a number of fundamental questions about how the organic bulk heterojunction cell enables efficient long-lived and long-range charge separation remain unanswered. These questions were address by employing an advanced suite of EPR spectroscopy in combination with DFT calculations to study mechanism of charge separation at the polymer-fullerene interfaces of photo-active BHJ. Observed charge delocalization in BHJ upon photoinduced ET is analogous to that in organic donor-acceptor material. This is an efficient mechanism of charge stabilization in photosynthetic assemblies. Time-resolved EPR spectra show a strong polarization pattern for all polymer-fullerene blends under study, which is caused by non-Boltzmann population of the electron spin energy levels in the radical pairs. The first observation of this phenomenon was reported in natural and artificial photosynthetic assemblies, and comparison with these systems allows us to better understand charge separation processes in OPVs. The spectral analysis presented here, in combination with DFT calculations, shows that CS processes in OPV materials are similar to that in organic photosynthetic systems. This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences, under Contract DE-AC02-06CH11357 at Argonne National Laboratory.

  4. Light dependence of quantum yields for PSII charge separation and oxygen evolution in eucaryotic algae

    NARCIS (Netherlands)

    Flameling, I.A.; Kromkamp, J.C.

    1998-01-01

    Quantum yields of photosystem II (PSII) charge separation (Phi(P)) and oxygen production (Phi(O2)) were determined by simultaneous measurements of oxygen production and variable fluorescence in four different aquatic microalgae representing three different taxonomic groups: the freshwater alga

  5. Conductivity rules in the Fermi and charge-spin separated liquid

    International Nuclear Information System (INIS)

    Arulsamy, Andrew Das

    2005-01-01

    Ioffe-Larkin rule applies for the pure charge-spin separation regardless of its dimensionality. Here, an extension to this rule as a result of the coexistence of spinon, holon and electron as a single entity in the 2-dimensional (2D) system is derived, which is also in accordance with the original rule

  6. Charge separation in contact systems with CdSe quantum dot layers

    International Nuclear Information System (INIS)

    Zillner, Elisabeth Franziska

    2013-01-01

    Quantum dot (QD) solar cells are a fast developing area in the field of solution processed photovoltaics. Central aspects for the application of QDs in solar cells are separation and transport of charge carriers in the QD layers and the formation of charge selective contacts. Even though efficiencies of up to 7% were reached in QD solar cells, these processes are not yet fully understood. In this thesis the mechanisms of charge separation, transport and recombination in CdSe QD layers and layer systems were studied. Charge separation was measured via surface photovoltage (SPV) at CdSe QD layers with thicknesses in the range of monolayers. To determine the influence of interparticle distance of QDs and trap states on the surface of QDs on charge separation, QDs with four different surfactant layers were studied. Layers of CdSe QDs were prepared on ITO, Si, SiO 2 and CdS by dip coating under inert atmosphere. The layers were characterized by Rutherford backscattering spectrometry, UV-vis spectroscopy, step profilometry and scanning electron microscopy to determine the areal density, the absorption and thickness of CdSe QD monolayers. SPV measurements show that initial charge separation from the CdSe QDs on ITO only happened from the fi rst monolayer of QDs. Electrons, photo-excited in the fi rst monolayer of CdSe QDs, were trapped on the ITO surface. The remaining free holes were trapped in surface states and/or diffused into the neighboring QD layers. The thick surfactant layer (∼ 1.6 nm) of pristine QDs had to be reduced by washing and/or ligand exchange for separation of photo-excited charge carriers. Both, interparticle distance and trap density, influenced the processes of charge separation and recombination. SPV transients of CdSe monolayers could be described by a single QD approximation model, based on Miller-Abrahams hopping of holes between the delocalized excitonic state, traps on the surface of the QD and the filled trap on the ITO surface

  7. Charge separation in contact systems with CdSe quantum dot layers

    Energy Technology Data Exchange (ETDEWEB)

    Zillner, Elisabeth Franziska

    2013-03-06

    Quantum dot (QD) solar cells are a fast developing area in the field of solution processed photovoltaics. Central aspects for the application of QDs in solar cells are separation and transport of charge carriers in the QD layers and the formation of charge selective contacts. Even though efficiencies of up to 7% were reached in QD solar cells, these processes are not yet fully understood. In this thesis the mechanisms of charge separation, transport and recombination in CdSe QD layers and layer systems were studied. Charge separation was measured via surface photovoltage (SPV) at CdSe QD layers with thicknesses in the range of monolayers. To determine the influence of interparticle distance of QDs and trap states on the surface of QDs on charge separation, QDs with four different surfactant layers were studied. Layers of CdSe QDs were prepared on ITO, Si, SiO{sub 2} and CdS by dip coating under inert atmosphere. The layers were characterized by Rutherford backscattering spectrometry, UV-vis spectroscopy, step profilometry and scanning electron microscopy to determine the areal density, the absorption and thickness of CdSe QD monolayers. SPV measurements show that initial charge separation from the CdSe QDs on ITO only happened from the fi rst monolayer of QDs. Electrons, photo-excited in the fi rst monolayer of CdSe QDs, were trapped on the ITO surface. The remaining free holes were trapped in surface states and/or diffused into the neighboring QD layers. The thick surfactant layer ({approx} 1.6 nm) of pristine QDs had to be reduced by washing and/or ligand exchange for separation of photo-excited charge carriers. Both, interparticle distance and trap density, influenced the processes of charge separation and recombination. SPV transients of CdSe monolayers could be described by a single QD approximation model, based on Miller-Abrahams hopping of holes between the delocalized excitonic state, traps on the surface of the QD and the filled trap on the ITO surface

  8. The impact of long-range electron-hole interaction on the charge separation yield of molecular photocells

    Science.gov (United States)

    Nemati Aram, Tahereh; Ernzerhof, Matthias; Asgari, Asghar; Mayou, Didier

    2017-01-01

    We discuss the effects of charge carrier interaction and recombination on the operation of molecular photocells. Molecular photocells are devices where the energy conversion process takes place in a single molecular donor-acceptor complex attached to electrodes. Our investigation is based on the quantum scattering theory, in particular on the Lippmann-Schwinger equation; this minimizes the complexity of the problem while providing useful and non-trivial insight into the mechanism governing photocell operation. In this study, both exciton pair creation and dissociation are treated in the energy domain, and therefore there is access to detailed spectral information, which can be used as a framework to interpret the charge separation yield. We demonstrate that the charge carrier separation is a complex process that is affected by different parameters, such as the strength of the electron-hole interaction and the non-radiative recombination rate. Our analysis helps to optimize the charge separation process and the energy transfer in organic solar cells and in molecular photocells.

  9. To the theory of spin-charge separation in one-dimensional correlated electron systems

    International Nuclear Information System (INIS)

    Zvyagin, A.A.

    2004-01-01

    Spin-charge separation is considered to be one of the key properties that distinguish low-dimensional electron systems from others. Three-dimensional correlated electron systems are described by the Fermi liquid theory. There, low-energy excitations (quasiparticles) are reminiscent of noninteracting electrons: They carry charges -e and spins 1/2 . It is believed that for any one-dimensional correlated electron system, low-lying electron excitations carry either only spin and no charge, or only charge without spin. That is why recent experiments looked for such low-lying collective electron excitations, one of which carries only spin, and the other carries only charge. Here we show that despite the fact that for exactly solvable one-dimensional correlated electron models there exist excitations which carry only spin and only charge, in all these models with short-range interactions the low-energy physics is described by low-lying collective excitations, one of which carries both spin and charge

  10. Space charge effects: tune shifts and resonances

    International Nuclear Information System (INIS)

    Weng, W.T.

    1986-08-01

    The effects of space charge and beam-beam interactions on single particle motion in the transverse degree of freedom are considered. The space charge force and the resulting incoherent tune shift are described, and examples are given from the AGS and CERN's PSB. Equations of motion are given for resonances in the presence of the space charge force, and particle behavior is examined under resonance and space charge conditions. Resonance phase space structure is described with and without space charge. Uniform and bunched beams are compared. Beam-beam forces and resonances and beam-beam detuning are described. 18 refs., 15 figs

  11. Rapid preparative separation of monoclonal antibody charge variants using laterally-fed membrane chromatography.

    Science.gov (United States)

    Sadavarte, Rahul; Madadkar, Pedram; Filipe, Carlos Dm; Ghosh, Raja

    2018-01-15

    Monoclonal antibodies undergo various forms of chemical transformation which have been shown to cause loss in efficacy and alteration in pharmacokinetic properties of these molecules. Such modified antibody molecules are known as variants. They also display physical properties such as charge that are different from intact antibody molecules. However, the difference in charge is very subtle and separation based on it is quite challenging. Charge variants are usually separated using ion-exchange column chromatography or isoelectric focusing. In this paper, we report a rapid and scalable method for fractionating monoclonal antibody charge variants, based on the use of cation exchange laterally-fed membrane chromatography (LFMC). Starting with a sample of monoclonal antibody hIgG1-CD4, three well-resolved fractions were obtained using either pH or salt gradient. These fractions were identified as acidic, neutral and basic variants. Each of these fractions contained intact heavy and light chains and so antibody fragmentation had no role in variant generation. The separation was comparable to that using column chromatography but was an order of magnitude faster. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Fluctuation charge effects in ionization fronts

    International Nuclear Information System (INIS)

    Arrayas, Manuel; Trueba, Jose L; Baltanas, J P

    2008-01-01

    In this paper, we study the effects of charge fluctuations on the propagation of both negative and positive ionization fronts in streamer discharges. We show that fronts accelerate when random charge creation events are present. This effect might play a similar role to photoionization in order to make the front move faster

  13. Fluctuation charge effects in ionization fronts

    Energy Technology Data Exchange (ETDEWEB)

    Arrayas, Manuel; Trueba, Jose L [Area de Electromagnetismo, Universidad Rey Juan Carlos, Camino del Molino s/n, 28943 Fuenlabrada, Madrid (Spain); Baltanas, J P [Departamento de Fisica Aplicada II, Universidad de Sevilla, Av. Reina Mercedes 2, 41012 Sevilla (Spain)

    2008-05-21

    In this paper, we study the effects of charge fluctuations on the propagation of both negative and positive ionization fronts in streamer discharges. We show that fronts accelerate when random charge creation events are present. This effect might play a similar role to photoionization in order to make the front move faster.

  14. Charge separation and transfer in hybrid type II tunneling structures of CdTe and CdSe nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Gross, Dieter Konrad Michael

    2013-11-08

    Closely packed nanocrystal systems have been investigated in this thesis with respect to charge separation by charge carrier tunneling. Clustered and layered samples have been analyzed using PL-measurements and SPV-methods. The most important findings are reviewed in the following. A short outlook is also provided for potential further aspects and application of the presented results. The main purpose of this thesis was to find and quantify electronic tunneling transfer in closely packed self-assembled nanocrystal structures presenting quantum mechanical barriers of about 1 nm width. We successfully used hybrid assemblies of CdTe and CdSe nanocrystals where the expected type II alignment between CdTe and CdSe typically leads to a concentration of electrons in CdSe and holes in CdTe nanocrystals. We were able to prove the charge selectivity of the CdTe-CdSe nanocrystal interface which induces charge separation. We mainly investigated the effects related to the electron transfer from CdTe to CdSe nanocrystals. Closely packing was achieved by two independent methods: the disordered colloidal clustering in solution and the layered assembly on dry glass substrates. Both methods lead to an inter-particle distance of about 1 nm of mainly organic material which acts as a tunneling barrier. PL-spectroscopy was applied. The PL-quenching of the CdTe nanocrystals in hybrid assemblies indicates charge separation by electron transfer from CdTe to CdSe nanocrystals. A maximum quenching rate of up to 1/100 ps was measured leading to a significant global PL-quenching of up to about 70 % for the CdTe nanocrystals. It was shown that charge separation dynamics compete with energy transfer dynamics and that charge separation typically dominates. The quantum confinement effect was used to tune the energetic offset between the CdTe and CdSe nanocrystals. We thus observe a correlation of PL-quenching and offset of the energy states for the electron transfer. The investigated PL

  15. Effective charge of energetic ions in metals

    International Nuclear Information System (INIS)

    Kitagawa, M.; Brandt, W.

    1983-01-01

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

  16. Distribution of separated energy and injected charge at normal falling of fast electron beam on target

    CERN Document Server

    Smolyar, V A; Eremin, V V

    2002-01-01

    In terms of a kinetic equation diffusion model for a beam of electrons falling on a target along the normal one derived analytical formulae for distributions of separated energy and injected charge. In this case, no empirical adjustable parameters are introduced to the theory. The calculated distributions of separated energy for an electron plate directed source within infinite medium for C, Al, Sn and Pb are in good consistency with the Spencer data derived on the basis of the accurate solution of the Bethe equation being the source one in assumption of a diffusion model, as well

  17. Distribution of separated energy and injected charge at normal falling of fast electron beam on target

    International Nuclear Information System (INIS)

    Smolyar, V.A.; Eremin, A.V.; Eremin, V.V.

    2002-01-01

    In terms of a kinetic equation diffusion model for a beam of electrons falling on a target along the normal one derived analytical formulae for distributions of separated energy and injected charge. In this case, no empirical adjustable parameters are introduced to the theory. The calculated distributions of separated energy for an electron plate directed source within infinite medium for C, Al, Sn and Pb are in good consistency with the Spencer data derived on the basis of the accurate solution of the Bethe equation being the source one in assumption of a diffusion model, as well [ru

  18. How exciton-vibrational coherences control charge separation in the photosystem II reaction center.

    Science.gov (United States)

    Novoderezhkin, Vladimir I; Romero, Elisabet; van Grondelle, Rienk

    2015-12-14

    In photosynthesis absorbed sun light produces collective excitations (excitons) that form a coherent superposition of electronic and vibrational states of the individual pigments. Two-dimensional (2D) electronic spectroscopy allows a visualization of how these coherences are involved in the primary processes of energy and charge transfer. Based on quantitative modeling we identify the exciton-vibrational coherences observed in 2D photon echo of the photosystem II reaction center (PSII-RC). We find that the vibrations resonant with the exciton splittings can modify the delocalization of the exciton states and produce additional states, thus promoting directed energy transfer and allowing a switch between the two charge separation pathways. We conclude that the coincidence of the frequencies of the most intense vibrations with the splittings within the manifold of exciton and charge-transfer states in the PSII-RC is not occurring by chance, but reflects a fundamental principle of how energy conversion in photosynthesis was optimized.

  19. Mass spectrometer provided with an optical system for separating neutron particles against charged particles

    Energy Technology Data Exchange (ETDEWEB)

    Reeher, J R; Story, M S; Smith, R D

    1977-03-03

    This invention concerns a mass spectrometer with an ion focusing optical system that efficiently separates the charged and neutral particles. It concerns an apparatus that can be used in ionisation areas operating at relatively high pressure (> 10/sup -2/ Torr). The invention relates more particularly to a mass spectrometer with an inlet device for the samples to be identified, a sample ionisation system for forming charged and neutral particles, a mass analyser and an optical system for focusing the ions formed in the mass analyser. The optics include several conducting components of which at least one has sides formed of grids, in the direction of the axis, towards the analyser the optics forming a potential well along the axis. The selected charged particles are focused in the analyser and the remaining particles can escape by the openings in the conducting grids.

  20. Picosecond absorption studies of photoinduced charge separation in polyelectrolyte bound aromatic chromophores

    Science.gov (United States)

    Shand, M. A.; Rodgers, M. A. J.; Webber, S. E.

    1991-02-01

    Picosecond absorption studies of photoinduced electron transfer between aromatic chromophores bound to polymethacrylic acid (P) and methylviologen (MV 2+ have been carried out in aqueous solution. The diphenylanthracene copolymer/viologen system at pH 2.8 shows the corresponding redox products DPA + rad and MV + rad arising from the singlet state of DPA with a forward rate constant of electron transfer of 2.6 × 10 9 s -1. At pH 9.0 the quenching of the S 1 state of DPA occurs with no charge separated products being observed. The pyrene copolymer shows no evidence of charge separated products at any pH in the range 2.8-9.0. It is proposed that the differences in the radical pair kinetics arise from differences in the degree of binding of the ground state complexes formed by the donor and acceptor species.

  1. A charge-polarized porous metal-organic framework for gas chromatographic separation of alcohols from water.

    Science.gov (United States)

    Sun, Jian-Ke; Ji, Min; Chen, Cheng; Wang, Wu-Gen; Wang, Peng; Chen, Rui-Ping; Zhang, Jie

    2013-02-25

    A bipyridinium ligand with a charge separated skeleton has been introduced into a metal-organic framework to yield a porous material with charge-polarized pore space, which exhibits selective adsorption for polar guest molecules and can be further used in gas chromatography for the separation of alcohol-water mixtures.

  2. Mass, charge, and energy separation by selective acceleration with a traveling potential hill

    Science.gov (United States)

    Tung, L. Schwager; Barr, W. L.; Lowder, R. S.; Post, R. F.

    1996-10-01

    A traveling electric potential hill has been used to generate an ion beam with an energy distribution that is mass dependent from a monoenergetic ion beam of mixed masses. This effect can be utilized as a novel method for mass separation applied to identification or enrichment of ions (e.g., of elements, isotopes, or molecules). This theory for mass-selective acceleration is presented here and is shown to be confirmed by experiment and by a time-dependent particle-in-cell computer simulation. Results show that monoenergetic ions with the particular mass of choice are accelerated by controlling the hill potential and the hill velocity. The hill velocity is typically 20%-30% faster than the ions to be accelerated. The ability of the hill to pickup a particular mass uses the fact that small kinetic energy differences in the lab frame appear much larger in the moving hill frame. Ions will gain energy from the approaching hill if their relative energy in the moving hill frame is less than the peak potential of the hill. The final energy of these accelerated ions can be several times the source energy, which facilitates energy filtering for mass purification or identification. If the hill potential is chosen to accelerate multiple masses, the heaviest mass will have the greatest final energy. Hence, choosing the appropriate hill potential and collector retarding voltage will isolate ions with the lightest, heaviest, or intermediate mass. In the experimental device, called a Solitron, purified 20Ne and 22Ne are extracted from a ribbon beam of neon that is originally composed of 20Ne:22Ne in the natural ratio of 91:9. The isotopic content of the processed beam is determined by measuring the energy distribution of the detected current. These results agree with the theory. In addition to mass selectivity, our theory can also be applied to the filtration of an ion beam according to charge state or energy. Because of this variety of properties, the Solitron is envisioned to

  3. Charge separation at disordered semiconductor heterojunctions from random walk numerical simulations.

    Science.gov (United States)

    Mandujano-Ramírez, Humberto J; González-Vázquez, José P; Oskam, Gerko; Dittrich, Thomas; Garcia-Belmonte, Germa; Mora-Seró, Iván; Bisquert, Juan; Anta, Juan A

    2014-03-07

    Many recent advances in novel solar cell technologies are based on charge separation in disordered semiconductor heterojunctions. In this work we use the Random Walk Numerical Simulation (RWNS) method to model the dynamics of electrons and holes in two disordered semiconductors in contact. Miller-Abrahams hopping rates and a tunnelling distance-dependent electron-hole annihilation mechanism are used to model transport and recombination, respectively. To test the validity of the model, three numerical "experiments" have been devised: (1) in the absence of constant illumination, charge separation has been quantified by computing surface photovoltage (SPV) transients. (2) By applying a continuous generation of electron-hole pairs, the model can be used to simulate a solar cell under steady-state conditions. This has been exploited to calculate open-circuit voltages and recombination currents for an archetypical bulk heterojunction solar cell (BHJ). (3) The calculations have been extended to nanostructured solar cells with inorganic sensitizers to study, specifically, non-ideality in the recombination rate. The RWNS model in combination with exponential disorder and an activated tunnelling mechanism for transport and recombination is shown to reproduce correctly charge separation parameters in these three "experiments". This provides a theoretical basis to study relevant features of novel solar cell technologies.

  4. Photochemical charges separation and photoelectric properties of flexible solar cells with two types of heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiangyang, E-mail: lxy081276@126.com, E-mail: yzgu@henu.edu.cn; Wang, Shun; Zheng, Haiwu; Cheng, Xiuying; Gu, Yuzong, E-mail: lxy081276@126.com, E-mail: yzgu@henu.edu.cn [Institute of Microsystems Physics and School of Physics and Electronics, Henan University, Kaifeng 475004 (China)

    2015-12-14

    Photochemical charges generation, separation, and transport at nanocrystal interfaces are central to energy conversion for solar cells. Here, Zn{sub 2}SnO{sub 4} nanowires/Cu{sub 4}Bi{sub 4}S{sub 9} (ZTO/CBS), ZTO nanowires/CBS-reduced graphene oxide (ZTO/CBS-RGO), and bulk heterojunction (BHJ) solar cells were measured. The signals of steady state and electric field-induced surface photovoltage indicate that RGO with high electron mobility can evidently improve the photovoltaic response. Besides, ZTO/CBS and ZTO/CBS-RGO cells exhibit the excellent performance and the highest efficiencies of 1.2% and 2.8%, respectively. The internal relations of photoelectric properties to some factors, such as film thickness, direct paths, RGO conductive network, energy level matching, etc., were discussed in detail. Qualitative and quantitative analyses further verified the comprehensive effect of RGO and other factors. Importantly, the fine bendable characteristic of BHJ solar cells with excellent efficiency and facile, scalable production gives the as-made flexible solar cells device potential for practical application in future.

  5. Gradient Self-Doped CuBi2O4 with Highly Improved Charge Separation Efficiency.

    Science.gov (United States)

    Wang, Fuxian; Septina, Wilman; Chemseddine, Abdelkrim; Abdi, Fatwa F; Friedrich, Dennis; Bogdanoff, Peter; van de Krol, Roel; Tilley, S David; Berglund, Sean P

    2017-10-25

    A new strategy of using forward gradient self-doping to improve the charge separation efficiency in metal oxide photoelectrodes is proposed. Gradient self-doped CuBi 2 O 4 photocathodes are prepared with forward and reverse gradients in copper vacancies using a two-step, diffusion-assisted spray pyrolysis process. Decreasing the Cu/Bi ratio of the CuBi 2 O 4 photocathodes introduces Cu vacancies that increase the carrier (hole) concentration and lowers the Fermi level, as evidenced by a shift in the flat band toward more positive potentials. Thus, a gradient in Cu vacancies leads to an internal electric field within CuBi 2 O 4 , which can facilitate charge separation. Compared to homogeneous CuBi 2 O 4 photocathodes, CuBi 2 O 4 photocathodes with a forward gradient show highly improved charge separation efficiency and enhanced photoelectrochemical performance for reduction reactions, while CuBi 2 O 4 photocathodes with a reverse gradient show significantly reduced charge separation efficiency and photoelectrochemical performance. The CuBi 2 O 4 photocathodes with a forward gradient produce record AM 1.5 photocurrent densities for CuBi 2 O 4 up to -2.5 mA/cm 2 at 0.6 V vs RHE with H 2 O 2 as an electron scavenger, and they show a charge separation efficiency of 34% for 550 nm light. The gradient self-doping accomplishes this without the introduction of external dopants, and therefore the tetragonal crystal structure and carrier mobility of CuBi 2 O 4 are maintained. Lastly, forward gradient self-doped CuBi 2 O 4 photocathodes are protected with a CdS/TiO 2 heterojunction and coated with Pt as an electrocatalyst. These photocathodes demonstrate photocurrent densities on the order of -1.0 mA/cm 2 at 0.0 V vs RHE and evolve hydrogen with a faradaic efficiency of ∼91%.

  6. Insights into collaborative separation process of photogenerated charges and superior performance of solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiangyang, E-mail: lxy081276@126.com; Wang, Shun; Zheng, Haiwu; Gu, Yuzong [Institute of Microsystems Physics and School of Physics and Electronics, Henan University, Kaifeng 475004 (China)

    2016-07-25

    ZnO nanowires/Cu{sub 4}Bi{sub 4}S{sub 9} (ZnO/CBS) and ZnO nanowires/CBS-graphene nanoplates (ZnO/CBS-GNs), as well as two types of solar cells were prepared. The photovoltaic responses of CBS-GNs and ZnO/CBS-GNs can be improved with incorporation of GNs. The transient surface photovoltage (TPV) can provide detailed information on the separation and transport of photogenerated carriers. The multichannel separation process from the TPVs indicates that the macro-photoelectric signals can be attributed to the photogenerated charges separated at the interface of CBS/GNs, rather than CBS/ZnO. The multi-interfacial recombination is the major carrier loss, and the hole selective p-V{sub 2}O{sub 5} can efficiently accelerate the charge extraction to the external circuit. The ZnO/CBS-GNs cell exhibits the superior performance, and the highest efficiency is 10.9%. With the adequate interfaces of CBS/GNs, GNs conductive network, energy level matching, etc., the excitons can easily diffuse to the interface of CBS/GNs, and the separated electrons and holes can be collected quickly, inducing the high photoelectric properties. Here, a facile strategy for solid state solar cells with superior performance presents a potential application.

  7. Cofactors involved in light-driven charge separation in photosystem I identified by subpicosecond infrared spectroscopy.

    Science.gov (United States)

    Di Donato, Mariangela; Stahl, Andreas D; van Stokkum, Ivo H M; van Grondelle, Rienk; Groot, Marie-Louise

    2011-02-01

    Photosystem I is one of the key players in the conversion of solar energy into chemical energy. While the chlorophyll dimer P(700) has long been identified as the primary electron donor, the components involved in the primary charge separation process in PSI remain undetermined. Here, we have studied the charge separation dynamics in Photosystem I trimers from Synechococcus elongatus by femtosecond vis-pump/mid-infrared-probe spectroscopy upon excitation at 700, 710, and 715 nm. Because of the high specificity of the infrared region for the redox state and small differences in the molecular structure of pigments, we were able to clearly identify specific marker bands indicating chlorophyll (Chl) oxidation. Magnitudes of chlorophyll cation signals are observed to increase faster than the time resolution of the experiment (~0.2 ps) upon both excitation conditions: 700 nm and selective red excitation. Two models, involving either ultrafast charge separation or charge transfer character of the red pigments in PSI, are discussed to explain this observation. A further increase in the magnitudes of cation signals on a subpicosecond time scale (0.8-1 ps) indicates the formation of the primary radical pair. Evolution in the cation region with time constants of 7 and 40 ps reveals the formation of the secondary radical pair, involving a secondary electron donor. Modeling of the data allows us to extract the spectra of the two radical pairs, which have IR signatures consistent with A+A₀- and P₇₀₀+A₁-. We conclude that the cofactor chlorophyll A acts as the primary donor in PSI. The existence of an equilibrium between the two radical pairs we interpret as concerted hole/electron transfer between the pairs of electron donors and acceptors, until after 40 ps, relaxation leads to a full population of the P₇₀₀+A₁. radical pair.

  8. On the Molecular Origin of Charge Separation at the Donor-Acceptor Interface

    KAUST Repository

    Sini, Gjergji

    2018-01-22

    Fullerene-based acceptors have dominated organic solar cells for almost two decades. It is only within the last few years that alternative acceptors rival their dominance, introducing much more flexibility in the optoelectronic properties of these material blends. However, a fundamental physical understanding of the processes that drive charge separation at organic heterojunctions is still missing, but urgently needed to direct further material improvements. Here a combined experimental and theoretical approach is used to understand the intimate mechanisms by which molecular structure contributes to exciton dissociation, charge separation, and charge recombination at the donor–acceptor (D–A) interface. Model systems comprised of polythiophene-based donor and rylene diimide-based acceptor polymers are used and a detailed density functional theory (DFT) investigation is performed. The results point to the roles that geometric deformations and direct-contact intermolecular polarization play in establishing a driving force (energy gradient) for the optoelectronic processes taking place at the interface. A substantial impact for this driving force is found to stem from polymer deformations at the interface, a finding that can clearly lead to new design approaches in the development of the next generation of conjugated polymers and small molecules.

  9. TITANIUM DIOXIDE TRIADS FOR IMPROVED CHARGE-SEPARATION USING CONDUCTIVE POLYMERS

    Energy Technology Data Exchange (ETDEWEB)

    Cochran, T.M.; Gaylor, T.N.; de la Garza, L.; Rajh, T.

    2009-01-01

    Dye-sensitized solar cells are potentially one of the best solutions to solar energy conversion because of the low cost of required materials and production processes. Titanium dioxide (TiO2) nanoparticulate fi lms are the basis for one of these types of cells, providing large surface area for dye-sensitizer adsorption. Because TiO2 nanoparticulate fi lms develop defects caused by oxygen defi ciency, deep reactive electron traps are formed. With the addition of an enediol ligand, these electron traps are deliberately removed, enhancing the conduction of electrons within the fi lm. In this project, TiO2 nanoparticulate fi lms made by a layer-by-layer dip coating method were modifi ed with 3,4-dihydroxyphenylacetic acid (DOPAC). DOPAC binds to the titanium atoms on the surface of the nanoparticles, restoring their octahedral geometry. This restructuring of the surface shifts the spectral properties of the TiO2 to the visible spectrum and improves the separation of charges which is observed using photoelectrochemistry. Furthermore, DOPAC enables the electronic attachment of other molecules to the surface of TiO2 fi lms, such as the conductive polymer polyaniline base. This conductive polymer provides an extended separation of charges which increases photocurrent production by forming a triad with the TiO2 semiconductor through the 3,4-dihydroxyphenylacetic acid linker. The photocurrent increases due to the donor properties of the conductive polymer thereby decreasing charge pair recombination.

  10. Theoretical Study of the Charge-Transfer State Separation within Marcus Theory

    DEFF Research Database (Denmark)

    Volpi, Riccardo; Nassau, Racine; Nørby, Morten Steen

    2016-01-01

    We study, within Marcus theory, the possibility of the charge-transfer (CT) state splitting at organic interfaces and a subsequent transport of the free charge carriers to the electrodes. As a case study we analyze model anthracene-C60 interfaces. Kinetic Monte Carlo (KMC) simulations on the cold...... CT state were performed at a range of applied electric fields, and with the fields applied at a range of angles to the interface to simulate the action of the electric field in a bulk heterojunction (BHJ) interface. The results show that the inclusion of polarization in our model increases CT state...... dissociation and charge collection. The effect of the electric field on CT state splitting and free charge carrier conduction is analyzed in detail with and without polarization. Also, depending on the relative orientation of the anthracene and C60 molecules at the interface, CT state splitting shows different...

  11. Photoinduced charge separation in a colloidal system of exfoliated layered semiconductor controlled by coexisting aluminosilicate clay.

    Science.gov (United States)

    Nakato, Teruyuki; Yamada, Yoshimi; Miyamoto, Nobuyoshi

    2009-02-05

    We investigated photoinduced charge separation occurring in a multicomponent colloidal system composed of oxide nanosheets of photocatalytically active niobate and photochemically inert clay and electron accepting methylviologen dications (MV2+). The inorganic nanosheets were obtained by exfoliation of layered hexaniobate and hectorite clay. The niobate and clay nanosheets were spatially separated in the colloidally dispersed state, and the MV2+ molecules were selectively adsorbed on the clay platelets. UV irradiation of the colloids led to electron transfer from the niobate nanosheets to the MV2+ molecules adsorbed on clay. The photoinduced electron transfer produced methylviologen radical cations (MV*+), which was characterized by high yield and long lifetime. The yield and stability of the MV*+ species were found to depend strongly on the clay content of the colloid: from a few mol % to approximately 70 mol % of the yield and several tens of minutes to more than 40 h of the lifetime. The contents of the niobate nanosheets and MV2+ molecules and the aging of the colloid also affected the photoinduced charge separation. In the absence of MV2+ molecules in the colloid, UV irradiation induced electron accumulation in the niobate nanosheets. The stability of the electron-accumulated state also depended on the clay content. The variation in the photochemical behavior is discussed in relation to the viscosity of the colloid.

  12. Study of the cold charge transfer state separation at the TQ1/PC71 BM interface.

    Science.gov (United States)

    Volpi, Riccardo; Linares, Mathieu

    2017-05-30

    Charge transfer (CT) state separation is one of the most critical processes in the functioning of an organic solar cell. In this article, we study a bilayer of TQ1 and PC 71 BM molecules presenting disorder at the interface, obtained by means of Molecular Dynamics. The study of the CT state splitting can be first analyzed through the CT state splitting diagram, introduced in a previous work. Through this analysis, we identify the possibility of CT state splitting within Marcus Theory in function of the electric field. Once the right range of electric fields has been identified, we perform Kinetic Monte Carlo simulations to estimate percentages and times for the CT state splitting and the free charge carriers collection. Statistical information extracted from these simulations allows us to highlight the importance of polarization and to test the limits of the predictions given by the CT state splitting diagram. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  13. Super spin-charge separation for class A, C and D disorder

    International Nuclear Information System (INIS)

    LeClair, Andre; Robinson, Dean J

    2008-01-01

    We prove versions of super spin-charge separation for all three of the symmetry groups SU(N), Sp(2N) and SO(N) of disordered Dirac fermions in 2 + 1 dimensions, which involve the supercurrent algebras gl(1|1) N ,osp(2|2) -2N and osp(2|2) N respectively. For certain restricted classes of disordered potentials, the latter supercurrent algebra based conformal field theories can arise as non-trivial low energy fixed points. For all cases with such a fixed point, we compute the density of states exponents as a function of N. (fast track communication)

  14. Understanding sensitization behavior of lead selenide photoconductive detectors by charge separation model

    International Nuclear Information System (INIS)

    Zhao, Lihua; Qiu, Jijun; Weng, Binbin; Chang, Caleb; Yuan, Zijian; Shi, Zhisheng

    2014-01-01

    We introduce a charge separation model in this work to explain the mechanism of enhanced photoconductivity of polycrystalline lead salt photoconductors. Our results show that this model could clarify the heuristic fabrication processes of such lead salt detectors that were not well understood and often considered mysterious for nearly a century. The improved lifetime and performance of the device, e.g., responsivity, are attributed to the spatial separation of holes and electrons, hence less possibility of carrier recombination. This model shows that in addition to crystal quality the size of crystallites, the depth of outer conversion layer, and doping concentration could all affect detector performance. The simulation results agree well with experimental results and thus offer a very useful tool for further improvement of lead salt detectors. The model was developed with lead salt family of photoconductors in mind, but may well be applicable to a wider class of semiconducting films

  15. Charge separation and carrier dynamics in donor-acceptor heterojunction photovoltaic systems.

    Science.gov (United States)

    Teuscher, Joël; Brauer, Jan C; Stepanov, Andrey; Solano, Alicia; Boziki, Ariadni; Chergui, Majed; Wolf, Jean-Pierre; Rothlisberger, Ursula; Banerji, Natalie; Moser, Jacques-E

    2017-11-01

    Electron transfer and subsequent charge separation across donor-acceptor heterojunctions remain the most important areas of study in the field of third-generation photovoltaics. In this context, it is particularly important to unravel the dynamics of individual ultrafast processes (such as photoinduced electron transfer, carrier trapping and association, and energy transfer and relaxation), which prevail in materials and at their interfaces. In the frame of the National Center of Competence in Research "Molecular Ultrafast Science and Technology," a research instrument of the Swiss National Science Foundation, several groups active in the field of ultrafast science in Switzerland have applied a number of complementary experimental techniques and computational simulation tools to scrutinize these critical photophysical phenomena. Structural, electronic, and transport properties of the materials and the detailed mechanisms of photoinduced charge separation in dye-sensitized solar cells, conjugated polymer- and small molecule-based organic photovoltaics, and high-efficiency lead halide perovskite solar energy converters have been scrutinized. Results yielded more than thirty research articles, an overview of which is provided here.

  16. Charge separation and carrier dynamics in donor-acceptor heterojunction photovoltaic systems

    Directory of Open Access Journals (Sweden)

    Joël Teuscher

    2017-11-01

    Full Text Available Electron transfer and subsequent charge separation across donor-acceptor heterojunctions remain the most important areas of study in the field of third-generation photovoltaics. In this context, it is particularly important to unravel the dynamics of individual ultrafast processes (such as photoinduced electron transfer, carrier trapping and association, and energy transfer and relaxation, which prevail in materials and at their interfaces. In the frame of the National Center of Competence in Research “Molecular Ultrafast Science and Technology,” a research instrument of the Swiss National Science Foundation, several groups active in the field of ultrafast science in Switzerland have applied a number of complementary experimental techniques and computational simulation tools to scrutinize these critical photophysical phenomena. Structural, electronic, and transport properties of the materials and the detailed mechanisms of photoinduced charge separation in dye-sensitized solar cells, conjugated polymer- and small molecule-based organic photovoltaics, and high-efficiency lead halide perovskite solar energy converters have been scrutinized. Results yielded more than thirty research articles, an overview of which is provided here.

  17. Theoretical perspectives on electron transfer and charge separation events in photochemical water cleavage systems

    International Nuclear Information System (INIS)

    Kozak, J.J.; Lenoir, P.M.; Musho, M.K.; Tembe, B.L.

    1984-01-01

    We study in this paper the dynamics induced by models for photochemical water cleavage systems, focusing on the spatial and temporal factors influencing electron transfer and charge separation processes in such systems. The reaction-diffusion theory is formulated in full generality and the consequences explored in a number of spatio-temporal regimes, viz. the spatially homogeneous system in the long-time limit (i.e. the steady state for a well-stirred system), the spatially homogeneous system in evolution, and the spatially inhomogeneous system in evolution (where, in the latter study, we consider electron transfer at the cluster surface to be governed by a rate constant that reflects the localized nature of such processes). The results of numerical simulations are presented for all three cases and used to highlight the importance of heterogeneous environments in enhancing the cage escape yield of charge separated species, and to demonstrate the dependence of the hydrogen yield on the localization of electron-transfer processes in the vicinity of the microcatalyst surface

  18. Generalized polymer effective charge measurement by capillary isotachophoresis

    Czech Academy of Sciences Publication Activity Database

    Chamieh, J.; Koval, Dušan; Besson, A.; Kašička, Václav; Cottet, H.

    2014-01-01

    Roč. 1370, Nov 28 (2014), s. 255-262 ISSN 0021-9673 R&D Projects: GA ČR(CZ) GA13-17224S; GA MŠk 7AMB12FR012 Grant - others:GA AV ČR(CZ) M200551207 Institutional support: RVO:61388963 Keywords : polymer effective charge * polyelectrolyte * isotachophoresis * counter-ion condensation * capillary electrophoresis Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.169, year: 2014

  19. String loop effect on the BRST charge

    International Nuclear Information System (INIS)

    Das, A.; Nishino, H.

    1987-07-01

    An effective BRST charge Q BRST which incorporates the string one-loop corrections is presented for the closed bosonic string in an arbitrary background. The effective σ-model action which leads to such a Q BRST is obtained and some consequences are discussed. (author). 14 refs, 1 fig

  20. Effective Electrostatic Interactions Between Two Overall Neutral Surfaces with Quenched Charge Heterogeneity Over Atomic Length Scale

    Science.gov (United States)

    Zhou, S.

    2017-12-01

    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

  1. Measurement of spin pumping voltage separated from extrinsic microwave effects

    International Nuclear Information System (INIS)

    Iguchi, Ryo; Saitoh, Eiji

    2017-01-01

    Conversions between spin and charge currents are core technologies in recent spintronics. In this article, we provide methods for estimating inverse spin Hall effects (ISHEs) induced by using microwave-driven spin pumping (SP) as a spin-current generator. ISHE and SP induce an electromotive force at the ferromagnetic or spin-wave resonance, which offers a valuable electric method of studying spin physics in materials. At the resonance, a microwave for exciting the magnetization dynamics induces an additional electromotive force via rf-current rectification and thermoelectric effects. We discuss methods of separating the signals generated from such extrinsic microwave effects by controlling sample structures and configurations. These methods are helpful in performing accurate measurements on ISHE induced by SP, enabling quantitative studies on the conversion between spin and charge currents on various kinds of materials. (author)

  2. Polymer depletion-driven cluster aggregation and initial phase separation in charged nanosized colloids

    Science.gov (United States)

    Gögelein, Christoph; Nägele, Gerhard; Buitenhuis, Johan; Tuinier, Remco; Dhont, Jan K. G.

    2009-05-01

    We study polymer depletion-driven cluster aggregation and initial phase separation in aqueous dispersions of charge-stabilized silica spheres, where the ionic strength and polymer (dextran) concentration are systematically varied, using dynamic light scattering and visual observation. Without polymers and for increasing salt and colloid content, the dispersions become increasingly unstable against irreversible cluster formation. By adding nonadsorbing polymers, a depletion-driven attraction is induced, which lowers the stabilizing Coulomb barrier and enhances the cluster growth rate. The initial growth rate increases with increasing polymer concentration and decreases with increasing polymer molar mass. These observations can be quantitatively understood by an irreversible dimer formation theory based on the classical Derjaguin, Landau, Verwey, and Overbeek pair potential, with the depletion attraction modeled by the Asakura-Oosawa-Vrij potential. At low colloid concentration, we observe an exponential cluster growth rate for all polymer concentrations considered, indicating a reaction-limited aggregation mechanism. At sufficiently high polymer and colloid concentrations, and lower salt content, a gas-liquidlike demixing is observed initially. Later on, the system separates into a gel and fluidlike phase. The experimental time-dependent state diagram is compared to the theoretical equilibrium phase diagram obtained from a generalized free-volume theory and is discussed in terms of an initial reversible phase separation process in combination with irreversible aggregation at later times.

  3. Separation analysis of macrolide antibiotics with good performance on a positively charged C18HCE column.

    Science.gov (United States)

    Wei, Jie; Shen, Aijin; Yan, Jingyu; Jin, Gaowa; Yang, Bingcheng; Guo, Zhimou; Zhang, Feifang; Liang, Xinmiao

    2016-03-01

    The separation of basic macrolide antibiotics suffers from peak tailing and poor efficiency on traditional silica-based reversed-phase liquid chromatography columns. In this work, a C18HCE column with positively charged surface was applied to the separation of macrolides. Compared with an Acquity BEH C18 column, the C18HCE column exhibited superior performance in the aspect of peak shape and separation efficiency. The screening of mobile phase additives including formic acid, acetic acid and ammonium formate indicated that formic acid was preferable for providing symmetrical peak shapes. Moreover, the influence of formic acid content was investigated. Analysis speed and mass spectrometry compatibility were also taken into account when optimizing the separation conditions for liquid chromatography coupled with tandem mass spectrometry. The developed method was successfully utilized for the determination of macrolide residues in a honey sample. Azithromycin was chosen as the internal standard for the quantitation of spiramycin and tilmicosin, while roxithromycin was used for erythromycin, tylosin, clarithromycin, josamycin and acetylisovaleryltylosin. Good correlation coefficients (r(2) > 0.9938) for all macrolides were obtained. The intra-day and inter-day recoveries were 73.7-134.7% and 80.7-119.7% with relative standard deviations of 2.5-8.0% and 3.9-16.1%, respectively. Outstanding sensitivity with limits of quantitation (S/N ≥ 10) of 0.02-1 μg/kg and limits of detection (S/N ≥ 3) of 0.01-0.5 μg/kg were achieved. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Long-lived charge-separated states in ligand-stabilized silver clusters

    KAUST Repository

    Pelton, Matthew; Tang, Yun; Bakr, Osman; Stellacci, Francesco

    2012-01-01

    Recently developed synthesis methods allow for the production of atomically monodisperse clusters of silver atoms stabilized in solution by aromatic thiol ligands, which exhibit intense absorption peaks throughout the visible and near-IR spectral regions. Here we investigated the time-dependent optical properties of these clusters. We observed two kinetic processes following ultrafast laser excitation of any of the absorption peaks: a rapid decay, with a time constant of 1 ps or less, and a slow decay, with a time constant that can be longer than 300 ns. Both time constants decrease as the polarity of the solvent increases, indicating that the two processes correspond to the formation and recombination, respectively, of a charge-separated state. The long lifetime of this state and the broad optical absorption spectrum mean that the ligand-stabilized silver clusters are promising materials for solar energy harvesting. © 2012 American Chemical Society.

  5. Long-lived charge-separated states in ligand-stabilized silver clusters

    KAUST Repository

    Pelton, Matthew

    2012-07-25

    Recently developed synthesis methods allow for the production of atomically monodisperse clusters of silver atoms stabilized in solution by aromatic thiol ligands, which exhibit intense absorption peaks throughout the visible and near-IR spectral regions. Here we investigated the time-dependent optical properties of these clusters. We observed two kinetic processes following ultrafast laser excitation of any of the absorption peaks: a rapid decay, with a time constant of 1 ps or less, and a slow decay, with a time constant that can be longer than 300 ns. Both time constants decrease as the polarity of the solvent increases, indicating that the two processes correspond to the formation and recombination, respectively, of a charge-separated state. The long lifetime of this state and the broad optical absorption spectrum mean that the ligand-stabilized silver clusters are promising materials for solar energy harvesting. © 2012 American Chemical Society.

  6. Improved Charge Separation in WO3/CuWO4 Composite Photoanodes for Photoelectrochemical Water Oxidation

    Directory of Open Access Journals (Sweden)

    Danping Wang

    2016-05-01

    Full Text Available Porous tungsten oxide/copper tungstate (WO3/CuWO4 composite thin films were fabricated via a facile in situ conversion method, with a polymer templating strategy. Copper nitrate (Cu(NO32 solution with the copolymer surfactant Pluronic®F-127 (Sigma-Aldrich, St. Louis, MO, USA, generic name, poloxamer 407 was loaded onto WO3 substrates by programmed dip coating, followed by heat treatment in air at 550 °C. The Cu2+ reacted with the WO3 substrate to form the CuWO4 compound. The composite WO3/CuWO4 thin films demonstrated improved photoelectrochemical (PEC performance over WO3 and CuWO4 single phase photoanodes. The factors of light absorption and charge separation efficiency of the composite and two single phase films were investigated to understand the reasons for the PEC enhancement of WO3/CuWO4 composite thin films. The photocurrent was generated from water splitting as confirmed by hydrogen and oxygen gas evolution, and Faradic efficiency was calculated based on the amount of H2 produced. This work provides a low-cost and controllable method to prepare WO3-metal tungstate composite thin films, and also helps to deepen the understanding of charge transfer in WO3/CuWO4 heterojunction.

  7. Space charge effect in the spiral inflector

    International Nuclear Information System (INIS)

    Toprek, Dragan

    2000-01-01

    This paper presents the analytical and numerical theory of the space charge effects in the beam in the spiral inflector. It considers a simplified model of a 'straight' cylindrical beam by using a uniform particle distribution. Numerical results represented in this paper are obtained by using a modified version of the program CASINO

  8. Charge separation in photoinitiated electron transfer reactions induced by a polyelectrolyte

    International Nuclear Information System (INIS)

    Meyerstein, D.; Rabani, J.; Matheson, M.S.; Meisel, D.

    1978-01-01

    When uncharged molecules quench the luminescence of Ru(bpy) 3 /sup 2+*/ by electron transfer to the quencher, the addition of poly(vinyl sulfate) (PVS) may, through its potential field, affect the rate of quenching, enhance the net separated charge yield, and slow the back reaction of the separated photoredox products. In all such cases that we have studied the quenching rate in the presence of PVS was reduced to about 60% of the rate measured in the absence of PVS. For two neutral species, iron(III) nitrilotriacetate (FeNTA) and cobalt(III) acetylacetonate (Co(acac) 3 ), photoreduction of the quencher was observed, and the redox yield escaping geminate recombination was substantially increased by added PVS. In the case of FeNTA the rate of the bulk back reaction was not changed appreciably by the presence of PVS owing to the rapid neutralization of Fe(NTA) - by protonation. For Co(acac) 3 the rate of the bulk back reaction was decreased by several orders of magnitude and the back reaction was shown to occur via the enolate form of the ligand which is released to the bulk solution. 4 figures, 4 tables

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

    Science.gov (United States)

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

    2017-09-01

    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.

  10. Complexation behavior of oppositely charged polyelectrolytes: Effect of charge distribution

    International Nuclear Information System (INIS)

    Zhao, Mingtian; Li, Baohui; Zhou, Jihan; Su, Cuicui; Niu, Lin; Liang, Dehai

    2015-01-01

    Complexation behavior of oppositely charged polyelectrolytes in a solution is investigated using a combination of computer simulations and experiments, focusing on the influence of polyelectrolyte charge distributions along the chains on the structure of the polyelectrolyte complexes. The simulations are performed using Monte Carlo with the replica-exchange algorithm for three model systems where each system is composed of a mixture of two types of oppositely charged model polyelectrolyte chains (EGEG) 5 /(KGKG) 5 , (EEGG) 5 /(KKGG) 5 , and (EEGG) 5 /(KGKG) 5 , in a solution including explicit solvent molecules. Among the three model systems, only the charge distributions along the chains are not identical. Thermodynamic quantities are calculated as a function of temperature (or ionic strength), and the microscopic structures of complexes are examined. It is found that the three systems have different transition temperatures, and form complexes with different sizes, structures, and densities at a given temperature. Complex microscopic structures with an alternating arrangement of one monolayer of E/K monomers and one monolayer of G monomers, with one bilayer of E and K monomers and one bilayer of G monomers, and with a mixture of monolayer and bilayer of E/K monomers in a box shape and a trilayer of G monomers inside the box are obtained for the three mixture systems, respectively. The experiments are carried out for three systems where each is composed of a mixture of two types of oppositely charged peptide chains. Each peptide chain is composed of Lysine (K) and glycine (G) or glutamate (E) and G, in solution, and the chain length and amino acid sequences, and hence the charge distribution, are precisely controlled, and all of them are identical with those for the corresponding model chain. The complexation behavior and complex structures are characterized through laser light scattering and atomic force microscopy measurements. The order of the apparent weight

  11. Space charge effect in an accelerated beam

    Directory of Open Access Journals (Sweden)

    G. Stupakov

    2008-01-01

    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.

  12. Charge separation relative to the reaction plane in Pb-Pb collisions at $\\sqrt{s_{NN}}$= 2.76 TeV

    CERN Document Server

    Abelev, Betty; Adamova, Dagmar; Adare, Andrew Marshall; Aggarwal, Madan; Aglieri Rinella, Gianluca; Agocs, Andras Gabor; Agostinelli, Andrea; Aguilar Salazar, Saul; Ahammed, Zubayer; Ahmad, Arshad; Ahmad, Nazeer; Ahn, Sang Un; Akindinov, Alexander; Aleksandrov, Dmitry; Alessandro, Bruno; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Almaraz Avina, Erick Jonathan; Alme, Johan; Alt, Torsten; Altini, Valerio; Altinpinar, Sedat; Altsybeev, Igor; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshauser, Harald; Arbor, Nicolas; Arcelli, Silvia; Armesto, Nestor; Arnaldi, Roberta; Aronsson, Tomas Robert; Arsene, Ionut Cristian; Arslandok, Mesut; Augustinus, Andre; Averbeck, Ralf Peter; Awes, Terry; Aysto, Juha Heikki; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; Bailhache, Raphaelle Marie; Bala, Renu; Baldini Ferroli, Rinaldo; Baldisseri, Alberto; Baldit, Alain; Baltasar Dos Santos Pedrosa, Fernando; Ban, Jaroslav; Baral, Rama Chandra; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Barret, Valerie; Bartke, Jerzy Gustaw; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batyunya, Boris; Baumann, Christoph Heinrich; Bearden, Ian Gardner; Beck, Hans; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bellwied, Rene; Belmont-Moreno, Ernesto; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bergognon, Anais Annick Erica; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhati, Ashok Kumar; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Bjelogrlic, Sandro; Blanco, F; Blanco, Francesco; Blau, Dmitry; Blume, Christoph; Bock, Nicolas; Boettger, Stefan; Bogdanov, Alexey; Boggild, Hans; Bogolyubsky, Mikhail; Boldizsar, Laszlo; Bombara, Marek; Book, Julian; Borel, Herve; Borissov, Alexander; Bose, Suvendu Nath; Bossu, Francesco; Botje, Michiel; Boyer, Bruno Alexandre; Braidot, Ermes; Braun-Munzinger, Peter; Bregant, Marco; Breitner, Timo Gunther; Browning, Tyler Allen; Broz, Michal; Brun, Rene; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Bugaiev, Kyrylo; Busch, Oliver; Buthelezi, Edith Zinhle; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Calvo Villar, Ernesto; Camerini, Paolo; Canoa Roman, Veronica; Cara Romeo, Giovanni; Carena, Francesco; Carena, Wisla; Carminati, Federico; Casanova Diaz, Amaya Ofelia; Castillo Castellanos, Javier Ernesto; Casula, Ester Anna Rita; Catanescu, Vasile; Cavicchioli, Costanza; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Chang, Beomsu; Chapeland, Sylvain; Charvet, Jean-Luc Fernand; Chattopadhyay, Sukalyan; Chattopadhyay, Subhasis; Chawla, Isha; Cherney, Michael Gerard; Cheshkov, Cvetan; Cheynis, Brigitte; Chiavassa, Emilio; Chibante Barroso, Vasco Miguel; Chinellato, David; Chochula, Peter; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Coccetti, Fabrizio; Colamaria, Fabio; Colella, Domenico; Conesa Balbastre, Gustavo; Conesa del Valle, Zaida; Constantin, Paul; Contin, Giacomo; Contreras, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortes Maldonado, Ismael; Cortese, Pietro; Cosentino, Mauro Rogerio; Costa, Filippo; Cotallo, Manuel Enrique; Crochet, Philippe; Cruz Alaniz, Emilia; Cuautle, Eleazar; Cunqueiro, Leticia; D'Erasmo, Ginevra; Dainese, Andrea; Dalsgaard, Hans Hjersing; Danu, Andrea; Das, Debasish; Das, Indranil; Das, Kushal; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; de Barros, Gabriel; De Caro, Annalisa; de Cataldo, Giacinto; de Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; De Marco, Nora; De Pasquale, Salvatore; de Rooij, Raoul Stefan; Delagrange, Hugues; Deloff, Andrzej; Demanov, Vyacheslav; Denes, Ervin; Deppman, Airton; Di Bari, Domenico; Di Giglio, Carmelo; Di Liberto, Sergio; Di Mauro, Antonio; Di Nezza, Pasquale; Diaz Corchero, Miguel Angel; Dietel, Thomas; Divia, Roberto; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Dobrowolski, Tadeusz Antoni; Dominguez, Isabel; Donigus, Benjamin; Dordic, Olja; Driga, Olga; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Dupieux, Pascal; Dutta Majumdar, AK; Dutta Majumdar, Mihir Ranjan; Elia, Domenico; Emschermann, David Philip; Engel, Heiko; Erazmus, Barbara; Erdal, Hege Austrheim; Espagnon, Bruno; Estienne, Magali Danielle; Esumi, Shinichi; Evans, David; Eyyubova, Gyulnara; Fabris, Daniela; Faivre, Julien; Falchieri, Davide; Fantoni, Alessandra; Fasel, Markus; Fedunov, Anatoly; Fehlker, Dominik; Feldkamp, Linus; Felea, Daniel; Fenton-Olsen, Bo; Feofilov, Grigory; Fernandez Tellez, Arturo; Ferretti, Alessandro; Ferretti, Roberta; Festanti, Andrea; Figiel, Jan; Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Francescon, Andrea; Frankenfeld, Ulrich Michael; Fuchs, Ulrich; Furget, Christophe; Fusco Girard, Mario; Gaardhoje, Jens Joergen; Gagliardi, Martino; Gago, Alberto; Gallio, Mauro; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Garabatos, Jose; Garcia-Solis, Edmundo; Garishvili, Irakli; Gerhard, Jochen; Germain, Marie; Geuna, Claudio; Gheata, Andrei George; Gheata, Mihaela; Ghidini, Bruno; Ghosh, Premomoy; Gianotti, Paola; Girard, Martin Robert; Giubellino, Paolo; Gladysz-Dziadus, Ewa; Glassel, Peter; Gomez, Ramon; Gonzalez Ferreiro, Elena; Gonzalez-Trueba, Laura Helena; Gonzalez-Zamora, Pedro; Gorbunov, Sergey; Goswami, Ankita; Gotovac, Sven; Grabski, Varlen; Graczykowski, Lukasz Kamil; Grajcarek, Robert; Grelli, Alessandro; Grigoras, Alina Gabriela; Grigoras, Costin; Grigoriev, Vladislav; Grigoryan, Ara; Grigoryan, Smbat; Grinyov, Boris; Grion, Nevio; Grosse-Oetringhaus, Jan Fiete; Grossiord, Jean-Yves; Grosso, Raffaele; Guber, Fedor; Guernane, Rachid; Guerra Gutierrez, Cesar; Guerzoni, Barbara; Guilbaud, Maxime Rene Joseph; Gulbrandsen, Kristjan Herlache; Gunji, Taku; Gupta, Anik; Gupta, Ramni; Gutbrod, Hans; Haaland, Oystein Senneset; Hadjidakis, Cynthia Marie; Haiduc, Maria; Hamagaki, Hideki; Hamar, Gergoe; Hanratty, Luke David; Hansen, Alexander; Harmanova, Zuzana; Harris, John William; Hartig, Matthias; Hasegan, Dumitru; Hatzifotiadou, Despoina; Hayrapetyan, Arsen; Heckel, Stefan Thomas; Heide, Markus Ansgar; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Herrmann, Norbert; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hicks, Bernard; Hille, Per Thomas; Hippolyte, Boris; Horaguchi, Takuma; Hori, Yasuto; Hristov, Peter Zahariev; Hrivnacova, Ivana; Huang, Meidana; Humanic, Thomas; Hwang, Dae Sung; Ichou, Raphaelle; Ilkaev, Radiy; Ilkiv, Iryna; Inaba, Motoi; Incani, Elisa; Innocenti, Gian Michele; Ippolitov, Mikhail; Irfan, Muhammad; Ivan, Cristian George; Ivanov, Andrey; Ivanov, Marian; Ivanov, Vladimir; Ivanytskyi, Oleksii; Jacobs, Peter; Janik, Malgorzata Anna; Janik, Rudolf; Jayarathna, Sandun; Jena, Satyajit; Jha, Deeptanshu Manu; Jimenez Bustamante, Raul Tonatiuh; Jirden, Lennart; Jones, Peter Graham; Jung, Hyung Taik; Jusko, Anton; Kakoyan, Vanik; Kalcher, Sebastian; Kalinak, Peter; Kalliokoski, Tuomo Esa Aukusti; Kalweit, Alexander Philipp; Kang, Ju Hwan; Kaplin, Vladimir; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karpechev, Evgeny; Kazantsev, Andrey; Kebschull, Udo Wolfgang; Keidel, Ralf; Khan, Mohisin Mohammed; Khan, Palash; Khan, Shuaib Ahmad; Khanzadeev, Alexei; Kharlov, Yury; Kileng, Bjarte; Kim, Beomkyu; Kim, Dong Jo; Kim, Do Won; Kim, Jonghyun; Kim, Jin Sook; Kim, Minwoo; Kim, Mimae; Kim, Se Yong; Kim, Seon Hee; Kim, Taesoo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Klay, Jennifer Lynn; Klein, Jochen; Klein-Bosing, Christian; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Koch, Kathrin; Kohler, Markus; Kollegger, Thorsten; Kolojvari, Anatoly; Kondratiev, Valery; Kondratyeva, Natalia; Konevskih, Artem; Korneev, Andrey; Kour, Ravjeet; Kowalski, Marek; Kox, Serge; Koyithatta Meethaleveedu, Greeshma; Kral, Jiri; Kralik, Ivan; Kramer, Frederick; Kraus, Ingrid Christine; Krawutschke, Tobias; Krelina, Michal; Kretz, Matthias; Krivda, Marian; Krizek, Filip; Krus, Miroslav; Kryshen, Evgeny; Krzewicki, Mikolaj; Kucheriaev, Yury; Kugathasan, Thanushan; Kuhn, Christian Claude; Kuijer, Paul; Kulakov, Igor; Kumar, Jitendra; Kurashvili, Podist; Kurepin, A; Kurepin, AB; Kuryakin, Alexey; Kushpil, Svetlana; Kushpil, Vasily; Kweon, Min Jung; Kwon, Youngil; La Pointe, Sarah Louise; La Rocca, Paola; Ladron de Guevara, Pedro; Lakomov, Igor; Langoy, Rune; Lara, Camilo Ernesto; Lardeux, Antoine Xavier; Lazzeroni, Cristina; Le Bornec, Yves; Lea, Ramona; Lechman, Mateusz; Lee, Graham Richard; Lee, Ki Sang; Lee, Sung Chul; Lefevre, Frederic; Lehnert, Joerg Walter; Leistam, Lars; Lemmon, Roy Crawford; Lenti, Vito; Leon Monzon, Ildefonso; Leon Vargas, Hermes; Leoncino, Marco; Levai, Peter; Lien, Jorgen; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Liu, Lijiao; Loggins, Vera; Loginov, Vitaly; Lohn, Stefan Bernhard; Lohner, Daniel; Loizides, Constantinos; Loo, Kai Krister; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lovhoiden, Gunnar; Lu, Xianguo; Luettig, Philipp; Lunardon, Marcello; Luo, Jiebin; Luparello, Grazia; Luquin, Lionel; Luzzi, Cinzia; Ma, Rongrong; Maevskaya, Alla; Mager, Magnus; Mahapatra, Durga Prasad; Maire, Antonin; Mal'Kevich, Dmitry; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Ludmila; Malzacher, Peter; Mamonov, Alexander; Manceau, Loic Henri Antoine; Manko, Vladislav; Manso, Franck; Manzari, Vito; Mao, Yaxian; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; Marin, Ana Maria; Marin Tobon, Cesar Augusto; Markert, Christina; Martashvili, Irakli; Martinengo, Paolo; Martinez, Mario Ivan; Martinez Davalos, Arnulfo; Martinez Garcia, Gines; Martynov, Yevgen; Mas, Alexis Jean-Michel; Masciocchi, Silvia; Masera, Massimo; Masoni, Alberto; Mastroserio, Annalisa; Matthews, Zoe Louise; Matyja, Adam Tomasz; Mayer, Christoph; Mazer, Joel; Mazzoni, Alessandra Maria; Meddi, Franco; Menchaca-Rocha, Arturo Alejandro; Mercado Perez, Jorge; Meres, Michal; Miake, Yasuo; Milano, Leonardo; Milosevic, Jovan; Mischke, Andre; Mishra, Aditya Nath; Miskowiec, Dariusz; Mitu, Ciprian Mihai; Mlynarz, Jocelyn; Mohanty, Bedangadas; Molnar, Levente; Montano Zetina, Luis Manuel; Monteno, Marco; Montes, Esther; Moon, Taebong; Morando, Maurizio; Moreira De Godoy, Denise Aparecida; Moretto, Sandra; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhuri, Sanjib; Mukherjee, Maitreyee; Muller, Hans; Munhoz, Marcelo; Musa, Luciano; Musso, Alfredo; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Nattrass, Christine; Naumov, Nikolay; Navin, Sparsh; Nayak, Tapan Kumar; Nazarenko, Sergey; Nazarov, Gleb; Nedosekin, Alexander; Nicassio, Maria; Niculescu, Mihai; Nielsen, Borge Svane; Niida, Takafumi; Nikolaev, Sergey; Nikolic, Vedran; Nikulin, Sergey; Nikulin, Vladimir; Nilsen, Bjorn Steven; Nilsson, Mads Stormo; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Novitzky, Norbert; Nyanin, Alexandre; Nyatha, Anitha; Nygaard, Casper; Nystrand, Joakim Ingemar; Oeschler, Helmut Oskar; Oh, Saehanseul; Oh, Sun Kun; Oleniacz, Janusz; Oppedisano, Chiara; Ortona, Giacomo; Oskarsson, Anders Nils Erik; Otwinowski, Jacek Tomasz; Oyama, Ken; Pachmayer, Yvonne Chiara; Pachr, Milos; Padilla, Fatima; Pagano, Paola; Paic, Guy; Painke, Florian; Pajares, Carlos; Pal, Susanta Kumar; Palaha, Arvinder Singh; Palmeri, Armando; Papikyan, Vardanush; Pappalardo, Giuseppe; Park, Woo Jin; Passfeld, Annika; Patalakha, Dmitri Ivanovich; Paticchio, Vincenzo; Pavlinov, Alexei; 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Quercigh, Emanuele; Qvigstad, Henrik; Rachevski, Alexandre; Rademakers, Alphonse; Raiha, Tomi Samuli; Rak, Jan; Rakotozafindrabe, Andry Malala; Ramello, Luciano; Ramirez Reyes, Abdiel; Raniwala, Rashmi; Raniwala, Sudhir; Rasanen, Sami Sakari; Rascanu, Bogdan Theodor; Rathee, Deepika; Read, Kenneth Francis; Real, Jean-Sebastien; Redlich, Krzysztof; Rehman, Attiq Ur; Reichelt, Patrick; Reicher, Martijn; Renfordt, Rainer Arno Ernst; Reolon, Anna Rita; Reshetin, Andrey; Rettig, Felix Vincenz; Revol, Jean-Pierre; Reygers, Klaus Johannes; Riccati, Lodovico; Ricci, Renato Angelo; Richert, Tuva; Richter, Matthias Rudolph; Riedler, Petra; Riegler, Werner; Riggi, Francesco; Rodrigues Fernandes Rabacal, Bartolomeu; Rodriguez Cahuantzi, Mario; Rodriguez Manso, Alis; Roed, Ketil; Rohr, David; Rohrich, Dieter; Romita, Rosa; Ronchetti, Federico; Rosnet, Philippe; Rossegger, Stefan; Rossi, Andrea; Roy, Christelle Sophie; Roy, Pradip Kumar; Rubio Montero, Antonio Juan; Rui, Rinaldo; Russo, Riccardo; Ryabinkin, Evgeny; Rybicki, Andrzej; Sadovsky, Sergey; Safarik, Karel; Sahoo, Raghunath; Sahu, Pradip Kumar; Saini, Jogender; Sakaguchi, Hiroaki; Sakai, Shingo; Sakata, Dosatsu; Salgado, Carlos Albert; Salzwedel, Jai; Sambyal, Sanjeev Singh; Samsonov, Vladimir; Sanchez Castro, Xitzel; Sandor, Ladislav; Sandoval, Andres; Sano, Masato; Sano, Satoshi; Santo, Rainer; Santoro, Romualdo; Sarkamo, Juho Jaako; Scapparone, Eugenio; Scarlassara, Fernando; Scharenberg, Rolf Paul; Schiaua, Claudiu Cornel; Schicker, Rainer Martin; Schmidt, Christian Joachim; Schmidt, Hans Rudolf; Schreiner, Steffen; Schuchmann, Simone; Schukraft, Jurgen; Schutz, Yves Roland; Schwarz, Kilian Eberhard; Schweda, Kai Oliver; Scioli, Gilda; Scomparin, Enrico; Scott, Patrick Aaron; Scott, Rebecca; Segato, Gianfranco; Selyuzhenkov, Ilya; Senyukov, Serhiy; Seo, Jeewon; Serci, Sergio; Serradilla, Eulogio; Sevcenco, Adrian; Shabetai, Alexandre; Shabratova, Galina; Shahoyan, Ruben; Sharma, Natasha; Sharma, Satish; Shigaki, Kenta; Shimomura, Maya; Shtejer, Katherin; Sibiriak, Yury; Siciliano, Melinda; Sicking, Eva; Siddhanta, Sabyasachi; Siemiarczuk, Teodor; Silvermyr, David Olle Rickard; Silvestre, Catherine; Simatovic, Goran; Simonetti, Giuseppe; Singaraju, Rama Narayana; Singh, Ranbir; Singha, Subhash; Singhal, Vikas; Sinha, Bikash; Sinha, Tinku; Sitar, Branislav; Sitta, Mario; Skaali, Bernhard; Skjerdal, Kyrre; Smakal, Radek; Smirnov, Nikolai; Snellings, Raimond; Sogaard, Carsten; Soltz, Ron Ariel; Son, Hyungsuk; Song, Jihye; Song, Myunggeun; Soos, Csaba; Soramel, Francesca; Sputowska, Iwona; Spyropoulou-Stassinaki, Martha; Srivastava, Brijesh Kumar; Stachel, Johanna; Stan, Ionel; Stefanek, Grzegorz; Stefanini, Giorgio; Steinpreis, Matthew; Stenlund, Evert Anders; Steyn, Gideon Francois; Stiller, Johannes Hendrik; Stocco, Diego; Stolpovskiy, Mikhail; Strabykin, Kirill; Strmen, Peter; Suaide, Alexandre Alarcon do Passo; Subieta Vasquez, Martin Alfonso; Sugitate, Toru; Suire, Christophe Pierre; Sukhorukov, Mikhail; Sultanov, Rishat; Sumbera, Michal; Susa, Tatjana; Szanto de Toledo, Alejandro; Szarka, Imrich; Szczepankiewicz, Adam; Szostak, Artur Krzysztof; Szymanski, Maciej; Takahashi, Jun; Tapia Takaki, Daniel Jesus; Tarazona Martinez, Alfonso; Tauro, Arturo; Tejeda Munoz, Guillermo; Telesca, Adriana; Terrevoli, Cristina; Thader, Jochen Mathias; Thomas, Deepa; Tieulent, Raphael Noel; Timmins, Anthony; Toia, Alberica; Torii, Hisayuki; Tosello, Flavio; Trzaska, Wladyslaw Henryk; Tsuji, Tomoya; Tumkin, Alexandr; Turrisi, Rosario; Tveter, Trine Spedstad; Ulery, Jason Glyndwr; Ullaland, Kjetil; Ulrich, Jochen; Uras, Antonio; Urban, Jozef; Urciuoli, Guido Marie; Usai, Gianluca; Vajzer, Michal; Vala, Martin; Valencia Palomo, Lizardo; Vallero, Sara; van der Kolk, Naomi; van Leeuwen, Marco; Vande Vyvre, Pierre; Vannucci, Luigi; Vargas, Aurora Diozcora; Varma, Raghava; Vasileiou, Maria; Vasiliev, Andrey; Vechernin, Vladimir; Veldhoen, Misha; Venaruzzo, Massimo; Vercellin, Ermanno; Vergara, Sergio; Vernet, Renaud; Verweij, Marta; Vickovic, Linda; Viesti, Giuseppe; Vikhlyantsev, Oleg; Vilakazi, Zabulon; Villalobos Baillie, Orlando; Vinogradov, Alexander; Vinogradov, Leonid; Vinogradov, Yury; Virgili, Tiziano; Viyogi, Yogendra; Vodopianov, Alexander; Voloshin, Kirill; Voloshin, Sergey; Volpe, Giacomo; von Haller, Barthelemy; Vranic, Danilo; Øvrebekk, Gaute; Vrlakova, Janka; Vulpescu, Bogdan; Vyushin, Alexey; Wagner, Boris; Wagner, Vladimir; Wan, Renzhuo; Wang, Dong; Wang, Mengliang; Wang, Yifei; Wang, Yaping; Watanabe, Kengo; Weber, Michael; Wessels, Johannes; Westerhoff, Uwe; Wiechula, Jens; Wikne, Jon; Wilde, Martin Rudolf; Wilk, Alexander; Wilk, Grzegorz Andrzej; Williams, Crispin; Windelband, Bernd Stefan; Xaplanteris Karampatsos, Leonidas; Yaldo, Chris G; Yamaguchi, Yorito; Yang, Hongyan; Yang, Shiming; Yasnopolsky, Stanislav; Yi, JunGyu; Yin, Zhongbao; Yoo, In-Kwon; Yoon, Jongik; Yu, Weilin; Yuan, Xianbao; Yushmanov, Igor; Zach, Cenek; Zampolli, Chiara; Zaporozhets, Sergey; Zarochentsev, Andrey; Zavada, Petr; Zaviyalov, Nikolai; Zbroszczyk, Hanna Paulina; Zelnicek, Pierre; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Haitao; Zhang, Xiaoming; Zhou, Daicui; Zhou, Fengchu; Zhou, You; Zhu, Jianhui; Zhu, Xiangrong; Zichichi, Antonino; Zimmermann, Alice; Zinovjev, Gennady; Zoccarato, Yannick Denis; Zynovyev, Mykhaylo; Zyzak, Maksym

    2013-01-02

    Measurements of charge dependent azimuthal correlations with the ALICE detector at the LHC are reported for Pb-Pb collisions at $\\sqrt{s_{NN}}$ = 2.76 TeV. Two- and three-particle charge-dependent azimuthal correlations in the pseudo-rapidity range $|\\eta | < 0.8$ are presented as a function of the collision centrality, particle separation in pseudo-rapidity, and transverse momentum. A clear signal compatible with the expectation of a charge-dependent separation relative to the reaction plane is observed, which shows little or no collision energy dependence when compared to measurements at RHIC energies. Models incorporating effects of local parity violation in strong interactions fail to describe the observed collision energy dependence.

  13. Inertial effects in systems with magnetic charge

    Science.gov (United States)

    Armitage, N. P.

    2018-05-01

    This short article sets out some of the basic considerations that go into detecting the mass of quasiparticles with effective magnetic charge in solids. Effective magnetic charges may be appear as defects in particular magnetic textures. A magnetic monopole is a defect in this texture and as such these are not monopoles in the actual magnetic field B, but instead in the auxiliary field H. They may have particular properties expected for such quasiparticles such as magnetic charge and mass. This effective mass may-in principle-be detected in the same fashion that the mass is detected of other particles classically e.g. through their inertial response to time-dependent electromagnetic fields. I discuss this physics in the context of the "simple" case of the quantum spin ices, but aspects are broadly applicable. Based on extensions to Ryzkhin's model for classical spin ice, a hydrodynamic formulation can be given that takes into account inertial and entropic forces. Ultimately, a form for the susceptibility is obtained that is equivalent to the Rocard equation, which is a classic form used to account for inertial effects in the context of Debye-like relaxation.

  14. Development and use of thin film composite based positively charged nanofiltration membranes in separation of aqueous streams and nuclear effluents

    International Nuclear Information System (INIS)

    Dey, T.K.; Bindal, R.C.; Prabhakar, S.; Tewari, P.K.

    2010-01-01

    A new, positively charged, thin film composite (TFC) type nanofiltration membrane has been developed and studied for its use in various aqueous stream separations. The membrane, containing fixed quaternary ammonium moieties, was developed by insitu interfacial polymerization of a functionalized amine (polyethyleneimine) and terephthaloyl chloride on a suitable base membrane. The nature of the charge on the membrane was established by ATR FT IR spectroscopy and was estimated by determination of its ion exchange capacity. The membrane was tested for its performance in single solute feed systems containing salts of various combinations of univalent and bivalent ions (NaCl, Na 2 SO 4 , CaCl 2 and MgSO 4 ) in test cell as well as in 2512 spiral modules. The membrane gave differential separation profile for these solutes with high rejection for CaCl 2 and low rejection for Na 2 SO 4 due to positive charge on the membrane and the type of charge constituting the salts. The membrane was also used for separation of simulated effluent solution containing uranyl nitrate in combination with ammonium nitrate which is a common effluent generated in nuclear industry. Here also the membrane gave differential separation profile for uranyl nitrate and ammonium nitrate in their mixture by concentrating the former salt and passing the later. This helped separation of these two solutes in the mixture into two different streams. (author)

  15. Integration of Semiconducting Sulfides for Full-Spectrum Solar Energy Absorption and Efficient Charge Separation.

    Science.gov (United States)

    Zhuang, Tao-Tao; Liu, Yan; Li, Yi; Zhao, Yuan; Wu, Liang; Jiang, Jun; Yu, Shu-Hong

    2016-05-23

    The full harvest of solar energy by semiconductors requires a material that simultaneously absorbs across the whole solar spectrum and collects photogenerated electrons and holes separately. The stepwise integration of three semiconducting sulfides, namely ZnS, CdS, and Cu2-x S, into a single nanocrystal, led to a unique ternary multi-node sheath ZnS-CdS-Cu2-x S heteronanorod for full-spectrum solar energy absorption. Localized surface plasmon resonance (LSPR) in the nonstoichiometric copper sulfide nanostructures enables effective NIR absorption. More significantly, the construction of pn heterojunctions between Cu2-x S and CdS leads to staggered gaps, as confirmed by first-principles simulations. This band alignment causes effective electron-hole separation in the ternary system and hence enables efficient solar energy conversion. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Strategies for Efficient Charge Separation and Transfer in Artificial Photosynthesis of Solar Fuels.

    Science.gov (United States)

    Xu, Yuxing; Li, Ailong; Yao, Tingting; Ma, Changtong; Zhang, Xianwen; Shah, Jafar Hussain; Han, Hongxian

    2017-11-23

    Converting sunlight to solar fuels by artificial photosynthesis is an innovative science and technology for renewable energy. Light harvesting, photogenerated charge separation and transfer (CST), and catalytic reactions are the three primary steps in the processes involved in the conversion of solar energy to chemical energy (SE-CE). Among the processes, CST is the key "energy pump and delivery" step in determining the overall solar-energy conversion efficiency. Efficient CST is always high priority in designing and assembling artificial photosynthesis systems for solar-fuel production. This Review not only introduces the fundamental strategies for CST but also the combinatory application of these strategies to five types of the most-investigated semiconductor-based artificial photosynthesis systems: particulate, Z-scheme, hybrid, photoelectrochemical, and photovoltaics-assisted systems. We show that artificial photosynthesis systems with high SE-CE efficiency can be rationally designed and constructed through combinatory application of these strategies, setting a promising blueprint for the future of solar fuels. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Radiation effects in charge coupled devices

    International Nuclear Information System (INIS)

    Williams, R.A.; Nelson, R.D.

    1975-01-01

    Charge coupled devices (CCD s) exhibit a number of advantages (low cost, low power, high bit density) in their several applications (serial memories, imagers, digital filters); however, fairly elementary theoretical considerations indicate that they will be very vulnerable to permanent radiation damage, by both neutrons and ionizing radiation, and to transient upset by pulsed ionizing radiation. Although studies of permanent ionizing-radiation damage in CCD's have been reported, little information has been published concerning their overall nuclear radiation vulnerability. This paper presents a fairly comprehensive experimental study of radiation effects in a 256-cell surface-channel, CCD shift-register. A limited amount of similar work is also presented for a 128-cell surface-channel device and a 130 cell peristaltic CCD shift register. The radiation effects phenomena discussed herein, include transient-ionizing-radiation responses, permanent ionizing- radiation damage to transfer efficiency, charge-carrying capacity and input transfer gate bias, and neutron damage to storage time--determined from dark current and charge-up time measurements

  18. Nonlinear charge reduction effect in strongly coupled plasmas

    International Nuclear Information System (INIS)

    Sarmah, D; Tessarotto, M; Salimullah, M

    2006-01-01

    The charge reduction effect, produced by the nonlinear Debye screening of high-Z charges occurring in strongly coupled plasmas, is investigated. An analytic asymptotic expression is obtained for the charge reduction factor (f c ) which determines the Debye-Hueckel potential generated by a charged test particle. Its relevant parametric dependencies are analysed and shown to predict a strong charge reduction effect in strongly coupled plasmas

  19. The influence of microstructure on charge separation dynamics in organic bulk heterojunction materials for solar cell applications

    KAUST Repository

    Scarongella, Mariateresa; Paraecattil, Arun Aby; Buchaca-Domingo, Ester; Douglas, Jessica D.; Beaupré , Serge; McCarthy-Ward, Thomas; Heeney, Martin J.; Moser, Jacques Edouard; Leclerc, Mario; Frechet, Jean; Stingelin, Natalie; Banerji, Natalie

    2014-01-01

    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.

  20. The rates of charge separation and energy destructive charge recombination processes within an organic dyad in presence of metal-semiconductor core shell nanocomposites.

    Science.gov (United States)

    Mandal, Gopa; Bhattacharya, Sudeshna; Das, Subrata; Ganguly, Tapan

    2012-01-01

    Steady state and time resolved spectroscopic measurements were made at the ambient temperature on an organic dyad, 1-(4-Chloro-phenyl)-3-(4-methoxy-naphthalen-1-yl)-propenone (MNCA), where the donor 1-methoxynaphthalene (1 MNT) is connected with the acceptor p-chloroacetophenone (PCA) by an unsaturated olefinic bond, in presence of Ag@TiO2 nanoparticles. Time resolved fluorescence and absorption measurements reveal that the rate parameters associated with charge separation, k(CS), within the dyad increases whereas charge recombination rate k(CR) reduces significantly when the surrounding medium is changed from only chloroform to mixture of chloroform and Ag@TiO2 (noble metal-semiconductor) nanocomposites. The observed results indicate that the dyad being combined with core-shell nanocomposites may form organic-inorganic nanocomposite system useful for developing light energy conversion devices. Use of metal-semiconductor nanoparticles may provide thus new ways to modulate charge recombination processes in light energy conversion devices. From comparison with the results obtained in our earlier investigations with only TiO2 nanoparticles, it is inferred that much improved version of light energy conversion device, where charge-separated species could be protected for longer period of time of the order of millisecond, could be designed by using metal-semiconductor core-shell nanocomposites rather than semiconductor nanoparticles only.

  1. Utilizing the dynamic stark shift as a probe for dielectric relaxation in photosynthetic reaction centers during charge separation.

    Science.gov (United States)

    Guo, Zhi; Lin, Su; Woodbury, Neal W

    2013-09-26

    In photosynthetic reaction centers, the electric field generated by light-induced charge separation produces electrochromic shifts in the transitions of reaction center pigments. The extent of this Stark shift indirectly reflects the effective field strength at a particular cofactor in the complex. The dynamics of the effective field strength near the two monomeric bacteriochlorophylls (BA and BB) in purple photosynthetic bacterial reaction centers has been explored near physiological temperature by monitoring the time-dependent Stark shift during charge separation (dynamic Stark shift). This dynamic Stark shift was determined through analysis of femtosecond time-resolved absorbance change spectra recorded in wild type reaction centers and in four mutants at position M210. In both wild type and the mutants, the kinetics of the dynamic Stark shift differ from those of electron transfer, though not in the same way. In wild type, the initial electron transfer and the increase in the effective field strength near the active-side monomer bacteriochlorophyll (BA) occur in synchrony, but the two signals diverge on the time scale of electron transfer to the quinone. In contrast, when tyrosine is replaced by aspartic acid at M210, the kinetics of the BA Stark shift and the initial electron transfer differ, but transfer to the quinone coincides with the decay of the Stark shift. This is interpreted in terms of differences in the dynamics of the local dielectric environment between the mutants and the wild type. In wild type, comparison of the Stark shifts associated with BA and BB on the two quasi-symmetric halves of the reaction center structure confirm that the effective dielectric constants near these cofactors are quite different when the reaction center is in the state P(+)QA(-), as previously determined by Steffen et al. at 1.5 K (Steffen, M. A.; et al. Science 1994, 264, 810-816). However, it is not possible to determine from static, low-temperature measurments if the

  2. Charge separation in excitonic and bipolar solar cells - A detailed balance approach

    International Nuclear Information System (INIS)

    Kirchartz, Thomas; Rau, Uwe

    2008-01-01

    A generalized solar cell model for excitonic and classical, bipolar solar cells is developed that describes the combined transport and interaction of electrons, holes and excitons. Both, conventional inorganic solar cells as well as organic solar cells, where excitons play a dominant role for energy transport, turn out to be special cases of this model. Due to the inclusion of photon recycling effects, the approach is compatible with the principle of detailed balance and the Shockley-Queisser limit. We show how varying the interaction between excitons and charge carriers as well as varying the respective mobilities of the different species changes the operation mode of the solar cell path between excitonic and bipolar

  3. Liquid-liquid and liquid-solid phase separation and flocculation for a charged colloidal dispersion

    International Nuclear Information System (INIS)

    Lai, S.K.; Wu, K.L.

    2002-01-01

    We model the intercolloidal interaction by a hard-sphere Yukawa repulsion to which is added the long-range van der Waals attraction. In comparison with the Derjaguin-Landau-Verwey-Overbeek repulsion, the Yukawa repulsion explicitly incorporates the spatial correlations between colloids and small ions. As a result, the repulsive part can be expressed analytically and has a coupling strength depending on the colloidal volume fraction. By use of this two-body potential of mean force and in conjunction with a second-order thermodynamic perturbation theory, we construct the colloidal Helmholtz free energy and use it to calculate the thermodynamic quantities, pressure and chemical potential, needed in the determination of the liquid-liquid and liquid-solid phase diagrams. We examine, in an aqueous charged colloidal dispersion, the effects of the Hamaker constant and particle size on the conformation of a stable liquid-liquid phase transition calculated with respect to the liquid-solid coexistence phases. We find that there exists a threshold Hamaker constant or particle size whose value demarcates the stable liquid-liquid coexistence phases from their metastable counterparts. Applying the same technique and using the energetic criterion, we extend our calculations to study the flocculation phenomenon in aqueous charged colloids. Here, we pay due attention to determining the loci of a stability curve stipulated for a given temperature T 0 , and obtain the parametric phase diagram of the Hamaker constant vs the coupling strength or, at given surface potential, the particle size. By imposing T 0 to be the critical temperature T c , i.e., setting k B T 0 (=k B T c ) equal to a reasonable potential barrier, we arrive at the stability curve that marks the irreversible reversible phase transition. The interesting result is that there occurs a minimum size for the colloidal particles below (above) which the colloidal dispersion is driven to an irreversible (reversible) phase

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

    International Nuclear Information System (INIS)

    Veenendaal, Michel van

    2016-01-01

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

  5. Effects of image charges, interfacial charge discreteness, and surface roughness on the zeta potential of spherical electric double layers.

    Science.gov (United States)

    Gan, Zecheng; Xing, Xiangjun; Xu, Zhenli

    2012-07-21

    We investigate the effects of image charges, interfacial charge discreteness, and surface roughness on spherical electric double layer structures in electrolyte solutions with divalent counterions in the setting of the primitive model. By using Monte Carlo simulations and the image charge method, the zeta potential profile and the integrated charge distribution function are computed for varying surface charge strengths and salt concentrations. Systematic comparisons were carried out between three distinct models for interfacial charges: (1) SURF1 with uniform surface charges, (2) SURF2 with discrete point charges on the interface, and (3) SURF3 with discrete interfacial charges and finite excluded volume. By comparing the integrated charge distribution function and the zeta potential profile, we argue that the potential at the distance of one ion diameter from the macroion surface is a suitable location to define the zeta potential. In SURF2 model, we find that image charge effects strongly enhance charge inversion for monovalent interfacial charges, and strongly suppress charge inversion for multivalent interfacial charges. For SURF3, the image charge effect becomes much smaller. Finally, with image charges in action, we find that excluded volumes (in SURF3) suppress charge inversion for monovalent interfacial charges and enhance charge inversion for multivalent interfacial charges. Overall, our results demonstrate that all these aspects, i.e., image charges, interfacial charge discreteness, their excluding volumes, have significant impacts on zeta potentials of electric double layers.

  6. Charge Separation in Intermixed Polymer:PC70BM Photovoltaic Blends: Correlating Structural and Photophysical Length Scales as a Function of Blend Composition

    KAUST Repository

    Utzat, Hendrik; Dimitrov, Stoichko D.; Wheeler, Scot; Collado-Fregoso, Elisa; Tuladhar, Pabitra Shakya; Schroeder, Bob C.; McCulloch, Iain; Durrant, James R.

    2017-01-01

    A key challenge in achieving control over photocurrent generation by bulk-heterojunction organic solar cells is understanding how the morphology of the active layer impacts charge separation and in particular the separation dynamics within

  7. Nonlinear space charge effect of bunched beam in linac

    International Nuclear Information System (INIS)

    Chen Yinbao

    1992-02-01

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

  8. Exciplexes versus Loose Ion Pairs: How Does the Driving Force Impact the Initial Product Ratio of Photoinduced Charge Separation Reactions?

    Science.gov (United States)

    2014-01-01

    Many donor–acceptor systems can undergo a photoinduced charge separation reaction, yielding loose ion pairs (LIPs). LIPs can be formed either directly via (distant) electron transfer (ET) or indirectly via the dissociation of an initially formed exciplex or tight ion pair. Establishing the prevalence of one of the reaction pathways is challenging because differentiating initially formed exciplexes from LIPs is difficult due to similar spectroscopic footprints. Hence, no comprehensive reaction model has been established for moderately polar solvents. Here, we employ an approach based on the time-resolved magnetic field effect (MFE) of the delayed exciplex luminescence to distinguish the two reaction channels. We focus on the effects of the driving force of ET and the solvent permittivity. We show that, surprisingly, the exciplex channel is significant even for an exergonic ET system with a free energy of ET of −0.58 eV and for the most polar solutions studied (butyronitrile). Our findings demonstrate that exciplexes play a crucial role even in polar solvents and at moderate driving forces, contrary to what is usually assumed. PMID:25243054

  9. Accumulative charge separation for solar fuels production: coupling light-induced single electron transfer to multielectron catalysis.

    Science.gov (United States)

    Hammarström, Leif

    2015-03-17

    The conversion and storage of solar energy into a fuel holds promise to provide a significant part of the future renewable energy demand of our societies. Solar energy technologies today generate heat or electricity, while the large majority of our energy is used in the form of fuels. Direct conversion of solar energy to a fuel would satisfy our needs for storable energy on a large scale. Solar fuels can be generated by absorbing light and converting its energy to chemical energy by electron transfer leading to separation of electrons and holes. The electrons are used in the catalytic reduction of a cheap substrate with low energy content into a high-energy fuel. The holes are filled by oxidation of water, which is the only electron source available for large scale solar fuel production. Absorption of a single photon typically leads to separation of a single electron-hole pair. In contrast, fuel production and water oxidation are multielectron, multiproton reactions. Therefore, a system for direct solar fuel production must be able to accumulate the electrons and holes provided by the sequential absorption of several photons in order to complete the catalytic reactions. In this Account, the process is termed accumulative charge separation. This is considerably more complicated than charge separation on a single electron level and needs particular attention. Semiconductor materials and molecular dyes have for a long time been optimized for use in photovoltaic devices. Efforts are made to develop new systems for light harvesting and charge separation that are better optimized for solar fuel production than those used in the early devices presented so far. Significant progress has recently been made in the discovery and design of better homogeneous and heterogeneous catalysts for solar fuels and water oxidation. While the heterogeneous ones perform better today, molecular catalysts based on transition metal complexes offer much greater tunability of electronic and

  10. Direct evidence of charge separation in a metal-organic framework: efficient and selective photocatalytic oxidative coupling of amines via charge and energy transfer.

    Science.gov (United States)

    Xu, Caiyun; Liu, Hang; Li, Dandan; Su, Ji-Hu; Jiang, Hai-Long

    2018-03-28

    The selective aerobic oxidative coupling of amines under mild conditions is an important laboratory and commercial procedure yet a great challenge. In this work, a porphyrinic metal-organic framework, PCN-222, was employed to catalyze the reaction. Upon visible light irradiation, the semiconductor-like behavior of PCN-222 initiates charge separation, evidently generating oxygen-centered active sites in Zr-oxo clusters indicated by enhanced porphyrin π-cation radical signals. The photogenerated electrons and holes further activate oxygen and amines, respectively, to give the corresponding redox products, both of which have been detected for the first time. The porphyrin motifs generate singlet oxygen based on energy transfer to further promote the reaction. As a result, PCN-222 exhibits excellent photocatalytic activity, selectivity and recyclability, far superior to its organic counterpart, for the reaction under ambient conditions via combined energy and charge transfer.

  11. Effects of charge depletion in dusty plasmas

    International Nuclear Information System (INIS)

    Goertz, Imke; Greiner, Franko; Piel, Alexander

    2011-01-01

    The charge reduction effect is studied in dense dust clouds. The saturation currents of Langmuir probes are used to derive the density of ions and electrons, which are calibrated with the plasma oscillation method. The plasma potential inside the dust cloud is measured with an emissive probe, which also yields the floating potential in a heated nonemitting mode. The presence of the dust also affects the density and the plasma potential of the ambient plasma. The ion densities inside the dust cloud and in the ambient plasma are found equal, while the electron density is reduced inside the dust cloud. The measured potentials are compared with current models. Inclusion of the bi-Maxwellian distribution of the electrons leads to an improved description in the limit of low dust density. The strong increase of the floating and cloud potential for high dust density, predicted by the constant ion density model, is not confirmed.

  12. Space charge effects and electronic bistability

    International Nuclear Information System (INIS)

    Ruffini, A.; Strumia, F.; Tommasi, O.

    1996-01-01

    The excitation of metastable states in an atomic beam apparatus by means of electron collision is a widespread technique. The authors have observed a large bistable behaviour in apparatus designed to provide an intense and collimated beam of metastable helium by excitation with orthogonally impinging electrons. This bistable behaviour largely affects the efficiency of the apparatus and is therefore worth of being carefully investigated. The apparatus has an electrode configuration equivalent to that of a tetrode valve with large intergrid distances. The bistability consists in a hysteresis cycle in the curve of the anode current vs. grid voltage. Experimental measurements, supported by a simple theoretical model and by numerical simulation, stress out the crucial role played by space charge effects for the onset of bistability. A comparison with previous observations of this phenomenon is given. Spontaneous current oscillations with various shapes have been recorded in one of the two curves of the hysteresis cycle

  13. Intramolecular charge separation in spirobifluorene-based donor–acceptor compounds adsorbed on Au and indium tin oxide electrodes

    International Nuclear Information System (INIS)

    Heredia, Daniel; Otero, Luis; Gervaldo, Miguel; Fungo, Fernando; Dittrich, Thomas; Lin, Chih-Yen; Chi, Liang-Chen; Fang, Fu-Chuan; Wong, Ken-Tsung

    2013-01-01

    Surface photovoltage (SPV) measurements were performed with a Kelvin-probe in spirobifluorene-based donor (diphenylamine)–acceptor (dicyano or cyanoacrylic acid moieties) compounds adsorbed from highly diluted solutions onto Au and indium tin oxide electrode surfaces. Strong intramolecular charge separation (negative SPV signals up to more than 0.1 V) due to directed molecule adsorption was observed only for spirobifluorene donor–acceptor compounds with carboxylic acid moiety. SPV signals and onset energies of electronic transitions depended on ambience conditions. - Highlights: ► Fluorene donor–acceptor derivatives were adsorbed at Au and indium tin oxide. ► Surface photovoltage measurements were performed with a Kelvin-probe. ► Strong intra-molecular charge separation was observed. ► SPV signals depended on ambience conditions

  14. Direct convertor based upon space charge effects

    International Nuclear Information System (INIS)

    Gitomer, S.J.

    1977-01-01

    A device capable of converting directly the kinetic energy of charged particles into electrical energy is considered. The device differs from earlier ones (such as Post's periodic focus electrostatic direct convertor) in that it makes use of the space charge repulsion in a high density charged particle beam. The beam is directed into a monotonic decelerating electrostatic field of a several-stage planar-finned structure. The collector fins coincide with vacuum equipotential surfaces. Space charge blowup of the beam directs particles onto various collector fins. The energy efficiency of a 4-stage device has been determined using a numberical simulation approach. We find that efficiencies approaching 75 percent are possible. An approximate scaling law is derived for the space charge based direct converter and a comparison is made to the periodic focus direct convertor. We find the space charge based direct convertor to be superior to a number of ways

  15. $\\mu / \\pi$ Separation using Convolutional Neural Networks for the MicroBooNE Charged Current Inclusive Cross Section Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Esquivel, Jessica Nicole [Syracuse U.

    2018-01-01

    The purpose of this thesis was to use Convolutional Neural Networks (CNN) to separate $\\mu^{\\prime}$s and $\\pi^{\\prime}$s for use in increasing the acceptance rate of $\\mu^{\\prime}$s below the implemented 75cm track length cut in the Charged Current Inclusive (CC-Inclusive) event selection for the CC-Inclusive Cross-Section Measurement. In doing this, we increase acceptance rate for CC-Inclusive events below a specific momentum range.

  16. Molecular approaches to solar energy conversion: the energetic cost of charge separation from molecular-excited states.

    Science.gov (United States)

    Durrant, James R

    2013-08-13

    This review starts with a brief overview of the technological potential of molecular-based solar cell technologies. It then goes on to focus on the core scientific challenge associated with using molecular light-absorbing materials for solar energy conversion, namely the separation of short-lived, molecular-excited states into sufficiently long-lived, energetic, separated charges capable of generating an external photocurrent. Comparisons are made between different molecular-based solar cell technologies, with particular focus on the function of dye-sensitized photoelectrochemical solar cells as well as parallels with the function of photosynthetic reaction centres. The core theme of this review is that generating charge carriers with sufficient lifetime and a high quantum yield from molecular-excited states comes at a significant energetic cost-such that the energy stored in these charge-separated states is typically substantially less than the energy of the initially generated excited state. The role of this energetic loss in limiting the efficiency of solar energy conversion by such devices is emphasized, and strategies to minimize this energy loss are compared and contrasted.

  17. Design and synthesis of bipyridine platinum(II) bisalkynyl fullerene donor-chromophore-acceptor triads with ultrafast charge separation.

    Science.gov (United States)

    Lee, Sai-Ho; Chan, Chris Tsz-Leung; Wong, Keith Man-Chung; Lam, Wai Han; Kwok, Wai-Ming; Yam, Vivian Wing-Wah

    2014-07-16

    Donor-chromophore-acceptor triads, (PTZ)2-Pt(bpy)-C60 and ((t)BuPTZ)2-Pt(bpy)-C60, along with their model compound, (Ph)2-Pt(bpy)-C60, have been synthesized and characterized; their photophysical and electrochemical properties have been studied, and the origin of the absorption and emission properties has been supported by computational studies. The photoinduced electron transfer reactions have been investigated using the femtosecond and nanosecond transient absorption spectroscopy. In dichloromethane, (Ph)2-Pt(bpy)-C60 shows ultrafast triplet-triplet energy transfer from the (3)MLCT/LLCT excited state within 4 ps to give the (3)C60* state, while in (PTZ)2-Pt(bpy)-C60 and ((t)BuPTZ)2-Pt(bpy)-C60, charge-separated state forms within 400 fs from the (3)MLCT/LLCT excited state with efficiency of over 0.90, and the total efficiency with the contribution of (3)C60* is estimated to be 0.99. Although the forward electron transfer reactions are very rapid, the charge-separated state recombines to the singlet ground state at a time of hundreds of nanoseconds because of the difference in spin multiplicity between the charge-separated state and the ground state.

  18. Effects of charged particles on DNA

    International Nuclear Information System (INIS)

    Eguchi-Kasai, Kiyomi; Itsukaichi, Hiromi; Murakami, Masahiro

    1995-01-01

    It can be noted that it is not simple double strand breaks (dsb) but the non-reparable breaks that are associated with high biological effectiveness in the cell killing effect for high LET radiation. Here, we have examined the effectiveness of fast neutrons and low (initial energy = 12 MeV/u) or high (135 MeV/u) energy charged particles on cell death in 19 mammalian cell lines including radiosensitive mutants. Some of the radiosensitive lines were deficient in DNA dsb repair such as LX830, M10, V3, and L5178Y-S cells and showed lower values of relative biological effectiveness (RBE) for fast neutrons if compared with their parent cell lines. The other lines of human ataxia-telangiectasia fibroblasts, irs 1, irs 2, irs 3 and irs 1SF cells, which were also radiosensitive but known as proficient in dsb repair, showed moderate RBEs. Dsb repair deficient mutants showed low RBE values for heavy ions. These experimental findings suggest that the DNA repair system does not play a major role against the attack of high linear energy transfer (LET) radiations. Therefore, we hypothesize that a main cause of cell death induced by high LET radiations is due to non-reparable dsb, which are produced at a higher rate compared to low LET radiations. (author)

  19. The effect of ketone defects on the charge transport and charge recombination in polyfluorenes

    NARCIS (Netherlands)

    Kuik, M.; Wetzelaer, G.-J.A.H.; Laddé, J.G.; Nicolai, H.T.; Wildeman, J.; Sweelssen, J.; Blom, P.W.M.

    2011-01-01

    The effect of on-chain ketone defects on the charge transport of the polyfluorene derivative poly(9,9-dioctylfluorene) (PFO) is investigated. Using MoO3 as ohmic hole contact, the hole transport in a pristine PFO diode is observed to be limited by space-charge, whereas fluorenone contaminated PFO

  20. The Effect of Ketone Defects on the Charge Transport and Charge Recombination in Polyfluorenes

    NARCIS (Netherlands)

    Kuik, Martijn; Wetzelaer, Gert-Jan A. H.; Ladde, Jurre G.; Nicolai, Herman T.; Wildeman, Jurjen; Sweelssen, Jorgen; Blom, Paul W. M.; Sweelssen, Jörgen

    2011-01-01

    The effect of on-chain ketone defects on the charge transport of the polyfluorene derivative poly(9,9-dioctylfluorene) (PFO) is investigated. Using MoO3 as ohmic hole contact, the hole transport in a pristine PFO diode is observed to be limited by space-charge, whereas fluorenone contaminated PFO

  1. Charge-carrier dynamics and Coulomb effects in semiconductor tetrapods

    International Nuclear Information System (INIS)

    Mauser, Christian

    2011-01-01

    charge carriers were additionally studied at high excitation energies. An efficient multi-exciton emission of the CdSe/CdS tetrapods could be observed, which is to be lead back to the exciton phase-space filling and a reduced Auger effect. The larger volume of the longer tetrapods allows a dual emission from the CdSe and the CdS with comparable intensities. The occuring Coulomb effects between a spatially separated electron-hole pair were studied in CdSe/CdTe tetrapods, which exhibit a type-II transition. A correlation between the tetrapod leg length and the binding energy of the charge-transfer exciton could be established, which is also reproduced in the theoretical simulations.

  2. Enhancement of plasmon-induced charge separation efficiency by coupling silver nanocubes with a thin gold film

    Science.gov (United States)

    Akiyoshi, Kazutaka; Saito, Koichiro; Tatsuma, Tetsu

    2016-10-01

    Plasmon-induced charge separation (PICS), in which an energetic electron is injected from a plasmonic nanoparticle (NP) to a semiconductor on contact, is often inhibited by a protecting agent adsorbed on the NP. We addressed this issue for an Ag nanocube-TiO2 system by coating it with a thin Au layer or by inserting the Au layer between the nanocubes (NCs) and TiO2. Both of the electrodes exhibit much higher photocurrents due to PICS than the electrodes without the Au film or the Ag NCs. These photocurrent enhancements can be explained in terms of PICS with accelerated electron transfer, in which electron injection from the Ag NCs or Ag@Au core-shell NCs to TiO2 is promoted by the Au film, or PICS enhanced by a nanoantenna effect, in which the electron injection from the Au film to TiO2 is enhanced by optical near field generated by the Ag NC.

  3. A multi-passage spectrometer for charge-state separation at MLLTRAP

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Christine; Gartzke, Eva; Habs, Dietrich; Krug, Kevin; Szerypo, Jerzy; Thirolf, Peter [Fakultaet fuer Physik, LMU - Muenchen (Germany); Kolhinen, Veli [Department of Physics, University of Jyvaeskylae (Finland)

    2010-07-01

    MLLTRAP is a Penning trap mass spectrometer facility which is currently being commissioned at the Maier-Leibnitz Tandem Accelerator Laboratory in Garching. Here, atomic mass values are determined by comparison of cyclotron frequencies, {omega}{sub c}=qB/m, of stored ions with mass m and charge q in a strong magnetic field B, relative to those of well-known ion species. One of the future goals of MLLTRAP is to utilize highly-charged ions for an improvement in the achievable mass accuracy {delta}m/m. For this purpose, singly-charged ions will have to be injected into a charge-breeding device, such as an EBIT, and transferred back towards the Penning traps, while being q/A selected. A multi-passage-spectrometer (MPS) is being built to fulfill these tasks. It consists of a fast-ramping, round-pole dipole magnet with a four-way electrostatic mirror system. In this presentation, the planned MLLTRAP setup focussing on the q/A-selection with the MPS system is presented.

  4. Direct observation of ultrafast long-range charge separation at polymer–fullerene heterojunctions

    KAUST Repository

    Provencher, Franç oise; Bé rubé , Nicolas; Parker, Anthony W.; Greetham, Gregory M.; Towrie, Michael; Hellmann, Christoph; Cô té , Michel; Stingelin, Natalie; Silva, Carlos; Hayes, Sophia C.

    2014-01-01

    In polymeric semiconductors, charge carriers are polarons, which means that the excess charge deforms the molecular structure of the polymer chain that hosts it. This results in distinctive signatures in the vibrational modes of the polymer. Here, we probe polaron photogeneration dynamics at polymer:fullerene heterojunctions by monitoring its time-resolved resonance-Raman spectrum following ultrafast photoexcitation. We conclude that polarons emerge within 300 fs. Surprisingly, further structural evolution on ≤50-ps timescales is modest, indicating that the polymer conformation hosting nascent polarons is not significantly different from that near equilibrium. We interpret this as suggestive that charges are free from their mutual Coulomb potential because we would expect rich vibrational dynamics associated with charge-pair relaxation. We address current debates on the photocarrier generation mechanism at molecular heterojunctions, and our work is, to our knowledge, the first direct probe of molecular conformation dynamics during this fundamentally important process in these materials. © 2014 Macmillan Publishers Limited. All rights reserved.

  5. Direct observation of ultrafast long-range charge separation at polymer–fullerene heterojunctions

    KAUST Repository

    Provencher, Françoise

    2014-07-01

    In polymeric semiconductors, charge carriers are polarons, which means that the excess charge deforms the molecular structure of the polymer chain that hosts it. This results in distinctive signatures in the vibrational modes of the polymer. Here, we probe polaron photogeneration dynamics at polymer:fullerene heterojunctions by monitoring its time-resolved resonance-Raman spectrum following ultrafast photoexcitation. We conclude that polarons emerge within 300 fs. Surprisingly, further structural evolution on ≤50-ps timescales is modest, indicating that the polymer conformation hosting nascent polarons is not significantly different from that near equilibrium. We interpret this as suggestive that charges are free from their mutual Coulomb potential because we would expect rich vibrational dynamics associated with charge-pair relaxation. We address current debates on the photocarrier generation mechanism at molecular heterojunctions, and our work is, to our knowledge, the first direct probe of molecular conformation dynamics during this fundamentally important process in these materials. © 2014 Macmillan Publishers Limited. All rights reserved.

  6. Exploring effective interactions through transition charge density ...

    Indian Academy of Sciences (India)

    tematics like reduced transition probabilities B(E2) and static quadrupole moments Q(2) ... approximations of solving large scale shell model problems in Monte Carlo meth- ... We present the theoretical study of transition charge densities.

  7. Long-Lived Charge Separation at Heterojunctions between Semiconducting Single-Walled Carbon Nanotubes and Perylene Diimide Electron Acceptors

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hyun Suk [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Arias, Dylan H [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Blackburn, Jeffrey L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sisto, Thomas J. [Columbia University; Peurifoy, Samuel [Columbia University; Zhang, Boyuan [Columbia University; Nuckolls, Colin [Columbia University

    2018-04-13

    Nonfullerene electron acceptors have facilitated a recent surge in the efficiencies of organic solar cells, although fundamental studies of the nature of exciton dissociation at interfaces with nonfullerene electron acceptors are still relatively sparse. Semiconducting single-walled carbon nanotubes (s-SWCNTs), unique one-dimensional electron donors with molecule-like absorption and highly mobile charges, provide a model system for studying interfacial exciton dissociation. Here, we investigate excited-state photodynamics at the heterojunction between (6,5) s-SWCNTs and two perylene diimide (PDI)-based electron acceptors. Each of the PDI-based acceptors, hPDI2-pyr-hPDI2 and Trip-hPDI2, is deposited onto (6,5) s-SWCNT films to form a heterojunction bilayer. Transient absorption measurements demonstrate that photoinduced hole/electron transfer occurs at the photoexcited bilayer interfaces, producing long-lived separated charges with lifetimes exceeding 1.0 us. Both exciton dissociation and charge recombination occur more slowly for the hPDI2-pyr-hPDI2 bilayer than for the Trip-hPDI2 bilayer. To explain such differences, we discuss the potential roles of the thermodynamic charge transfer driving force available at each interface and the different molecular structure and intermolecular interactions of PDI-based acceptors. Detailed photophysical analysis of these model systems can develop the fundamental understanding of exciton dissociation between organic electron donors and nonfullerene acceptors, which has not been systematically studied.

  8. Azimuthal angle dependence of the charge imbalance from charge conservation effects

    Science.gov (United States)

    BoŻek, Piotr

    2018-03-01

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

  9. Effective charge versus bare charge: an analytical estimate for colloids in the infinite dilution limit

    International Nuclear Information System (INIS)

    Aubouy, Miguel; Trizac, Emmanuel; Bocquet, Lyderic

    2003-01-01

    We propose an analytical approximation for the dependence of the effective charge on the bare charge for spherical and cylindrical macro-ions as a function of the size of the colloid and salt content, for the situation of a unique colloid immersed in a sea of electrolyte (where the definition of an effective charge is non-ambiguous). Our approach is based on the Poisson-Boltzmann (PB) mean-field theory. Mathematically speaking, our estimate is asymptotically exact in the limit κa >> 1, where a is the radius of the colloid and κ is the inverse screening length. In practice, a careful comparison with effective charge parameters, obtained by numerically solving the full nonlinear PB theory, proves that our estimate is good down to κa ∼ 1. This is precisely the limit appropriate to treat colloidal suspensions. A particular emphasis is put on the range of parameters suitable to describe both single and double strand DNA molecules under physiological conditions

  10. Charge pattern matching as a ‘fuzzy’ mode of molecular recognition for the functional phase separations of intrinsically disordered proteins

    Science.gov (United States)

    Lin, Yi-Hsuan; Brady, Jacob P.; Forman-Kay, Julie D.; Chan, Hue Sun

    2017-11-01

    Biologically functional liquid-liquid phase separation of intrinsically disordered proteins (IDPs) is driven by interactions encoded by their amino acid sequences. Little is currently known about the molecular recognition mechanisms for distributing different IDP sequences into various cellular membraneless compartments. Pertinent physics was addressed recently by applying random-phase-approximation (RPA) polymer theory to electrostatics, which is a major energetic component governing IDP phase properties. RPA accounts for charge patterns and thus has advantages over Flory-Huggins (FH) and Overbeek-Voorn mean-field theories. To make progress toward deciphering the phase behaviors of multiple IDP sequences, the RPA formulation for one IDP species plus solvent is hereby extended to treat polyampholyte solutions containing two IDP species plus solvent. The new formulation generally allows for binary coexistence of two phases, each containing a different set of volume fractions ({φ }1,{φ }2) for the two different IDP sequences. The asymmetry between the two predicted coexisting phases with regard to their {φ }1/{φ }2 ratios for the two sequences increases with increasing mismatch between their charge patterns. This finding points to a multivalent, stochastic, ‘fuzzy’ mode of molecular recognition that helps populate various IDP sequences differentially into separate phase compartments. An intuitive illustration of this trend is provided by FH models, whereby a hypothetical case of ternary coexistence is also explored. Augmentations of the present RPA theory with a relative permittivity {ɛ }{{r}}(φ ) that depends on IDP volume fraction φ ={φ }1+{φ }2 lead to higher propensities to phase separate, in line with the case with one IDP species we studied previously. Notably, the cooperative, phase-separation-enhancing effects predicted by the prescriptions for {ɛ }{{r}}(φ ) we deem physically plausible are much more prominent than that entailed by common

  11. Space-charge effects of the proportional counters in a multiple-ionization chamber

    International Nuclear Information System (INIS)

    Mang, M.

    1993-01-01

    At the ALADIN spectrometer of the GSI in october 1991 for the first time the new multiple ionization chamber was applied, in the two anode planes of which are additional multiwire-proportional counters. The proportional counters are required in order to make the detection of light fragments (Z 4 gold projectiles per second by these positive space charges the homogeneous electric field of the MUSIC is disturbed. This effect is especially strong in the beam plane. As consequence of the space charge additionally electrons are focused on the proportional counter so that their amplitudes in dependence on the beam intensity increase up to the 2.5-fold. Furthermore the y coordinate is falsified, because the electrons are diverted to the medium plane. On the measurement of the x coordinate this diversion has with maximally 0.1% only a small influence. These space-charge effects can be qualitatively described by a schematic model, which assumes a stationary positive space charge. Additionally for the proportional counters, which are not in the beam plane, their resolution was determined. In these counters the space-charge effects are small, because essentially fewer particles are registrated than in the medium MWPC's. By this charges of fragments with Z<10 could be separated. The charge resolution amounted at lithium 0.8 charge units. The position resolution of the proportional counters in y direction was determined to less than 8 mm. The detection probability of the fragments amounts for lithium 90% and from boron all fragments are detected

  12. Study on the Effect of the Separating Unit Optimization on the Economy of Stable Isotope Separation

    Directory of Open Access Journals (Sweden)

    YANG Kun

    2015-01-01

    Full Text Available An economic criterion called as yearly net profit of single separating unit (YNPSSU was presented to evaluate the influence of structure optimization on the economy. Using YNPSSU as a criterion, economic analysis was carried out for the structure optimization of separating unit in the case of separating SiF4 to obtain the 28Si and 29Si isotope. YNPSSU was calculated and compared with that before optimization. The results showed that YNPSSU was increased by 12.3% by the structure optimization. Therefore, the structure optimization could increase the economy of the stable isotope separation effectively.

  13. The gauge-independent QCD effective charge

    International Nuclear Information System (INIS)

    Watson, N.J.

    1997-01-01

    It is shown how the QED concept of a gauge-, scale- and scheme-independent one-loop effective charge can be extended directly at the diagrammatic level to QCD, thus justifying explicitly the ''naive non-abelianization'' prescription used in renormalon calculus. It is first argued that, for on-shell external fields and at the strictly one-loop level, the required gluon self-energy-like function is precisely that obtained from S-matrix elements via the pinch technique. The generalization of the pinch technique to explicitly off-shell processes is then introduced. It is shown how, as a result of a fundamental cancellation among conventional perturbation theory diagrams, encoded in the QCD Ward identities, the pinch technique one-loop gluon self-energy iΠ μν ab (q) remains gauge-independent and universal regardless of the fact that the ''external'' fields in the given process are off-shell. This demonstration involves a simple technique enabling the isolation, in an arbitrary gauge, of iΠ μν ab (q) from subclasses of up to several hundred diagrams at once. Furthermore, it is shown how this one-loop cancellation mechanism iterates for the subclasses of n-loop diagrams containing implicitly the Dyson chains of n one-loop self-energies iΠ μν ab (q). The gauge cancellation required for the Dyson summation of iΠ μν ab (q) is thus demonstrated explicitly in a general class of ghost-free gauges for all orders n. (orig.)

  14. The gauge-independent QCD effective charge

    International Nuclear Information System (INIS)

    Watson, N.J.

    1999-01-01

    It is shown how the QCD concept of a gauge-, scale-and scheme-independent one-loop effective charge can be extended directly at the diagrammatic level to QCD, thus justifying explicitly the 'naive non-abelialization' prescription used in renormalon calculus. It is first argued that, for one-shell external fields and at the strictly one-loop level, the required gluon self-energy-like function is precisely that obtained from S-matrix elements via the pinch technique. The generalization of the pinch technique to explicitly off-shell processes is then introduced. It is shown how, as a result of a fundamental cancellation among conventional perturbation theory diagrams encoded in the QCD Ward identities, the pinch technique one-loop gluon self-energy iΠ μν ab (q) remains gauge-independent and universal regardless of the fact that the 'external' fields in the given process are off-shell. This demonstration involves a simple technique enabling the isolation in a arbitrary gauge, of iΠ μν ab (q) from subclasses of up to several hundreds diagrams at once. Furthermore, it is shown how this one-loop cancellation mechanism iterates for the subclasses of n-loop diagrams containing implicitly the Dyson chains of n-loop self energies iΠ μν ab (q). The gauge cancellation required for the Dyson summation of iΠ μν ab (q) is thus demonstrated explicitly in the class of ghost-free gauges for all orders n. (authors)

  15. Polarization Energies at Organic–Organic Interfaces: Impact on the Charge Separation Barrier at Donor–Acceptor Interfaces in Organic Solar Cells

    KAUST Repository

    Ryno, Sean

    2016-05-31

    We probe the energetic landscape at a model pentacene/fullerene-C60 interface to investigate the interactions between positive and negative charges, which are critical to the processes of charge separation and recombination in organic solar cells. Using a polarizable force field, we find that polarization energy, i.e. the stabilization a charge feels due to its environment, is larger at the interface than in the bulk for both a positive and a negative charge. The combination of the charge being more stabilized at the interface and the Coulomb attraction between the charges, results in a barrier to charge separation at the pentacene-C60 interface that can be in excess of 0.7 eV for static configurations of the donor and acceptor locations. However, the impact of molecular motions, i.e., the dynamics, at the interface at room temperature results in a distribution of polarization energies and in charge separation barriers that can be significantly reduced. The dynamic nature of the interface is thus critical, with the polarization energy distributions indicating that sites along the interface shift in time between favorable and unfavorable configurations for charge separation.

  16. Space charge effects in proton linear accelerators

    International Nuclear Information System (INIS)

    Prome, Michel

    1971-01-01

    Space charge difficulties are relatively well known because of the inconveniences they cause, but the physical mechanisms by which they operate are obscure; an attempt was made to explain some of these mechanisms. The method chosen involves a numerical simulation of the beam; computer programs describing beam dynamics with space charge are presented; they are used to check results obtained elsewhere. A series of experiments was performed demonstrating that coupling phenomena produce an equalization of r. m. s. velocities in the 3 directions; new quantity (sort of hyper-emittance) is introduced: its growth between the input and output of a given linac is proportional to the beam intensity. (author) [fr

  17. Charge Separation at Mixed-Dimensional Single and Multilayer MoS2/Silicon Nanowire Heterojunctions.

    Science.gov (United States)

    Henning, Alex; Sangwan, Vinod K; Bergeron, Hadallia; Balla, Itamar; Sun, Zhiyuan; Hersam, Mark C; Lauhon, Lincoln J

    2018-05-16

    Layered two-dimensional (2-D) semiconductors can be combined with other low-dimensional semiconductors to form nonplanar mixed-dimensional van der Waals (vdW) heterojunctions whose charge transport behavior is influenced by the heterojunction geometry, providing a new degree of freedom to engineer device functions. Toward that end, we investigated the photoresponse of Si nanowire/MoS 2 heterojunction diodes with scanning photocurrent microscopy and time-resolved photocurrent measurements. Comparison of n-Si/MoS 2 isotype heterojunctions with p-Si/MoS 2 heterojunction diodes under varying biases shows that the depletion region in the p-n heterojunction promotes exciton dissociation and carrier collection. We measure an instrument-limited response time of 1 μs, which is 10 times faster than the previously reported response times for planar Si/MoS 2 devices, highlighting the advantages of the 1-D/2-D heterojunction. Finite element simulations of device models provide a detailed understanding of how the electrostatics affect charge transport in nanowire/vdW heterojunctions and inform the design of future vdW heterojunction photodetectors and transistors.

  18. Theoretical Study of the Charge-Transfer State Separation within Marcus Theory: The C60-Anthracene Case Study.

    Science.gov (United States)

    Volpi, Riccardo; Nassau, Racine; Nørby, Morten Steen; Linares, Mathieu

    2016-09-21

    We study, within Marcus theory, the possibility of the charge-transfer (CT) state splitting at organic interfaces and a subsequent transport of the free charge carriers to the electrodes. As a case study we analyze model anthracene-C60 interfaces. Kinetic Monte Carlo (KMC) simulations on the cold CT state were performed at a range of applied electric fields, and with the fields applied at a range of angles to the interface to simulate the action of the electric field in a bulk heterojunction (BHJ) interface. The results show that the inclusion of polarization in our model increases CT state dissociation and charge collection. The effect of the electric field on CT state splitting and free charge carrier conduction is analyzed in detail with and without polarization. Also, depending on the relative orientation of the anthracene and C60 molecules at the interface, CT state splitting shows different behavior with respect to both applied field strength and applied field angle. The importance of the hot CT in helping the charge carrier dissociation is also analyzed in our scheme.

  19. Dynamics of Interfacial Charge Transfer States and Carriers Separation in Dye-Sensitized Solar Cells: A Time-Resolved Terahertz Spectroscopy Study

    OpenAIRE

    Brauer, Jan C.; Marchioro, Arianna; Paraecattil, Arun A.; Oskouei, Ahmad A.; Moser, Jacques-E.

    2015-01-01

    Electron injection from a photoexcited molecular sensitizer into a wide-bandgap semiconductor is the primary step toward charge separation in dye-sensitized solar cells (DSSCs). According to the current understanding of DSSCs functioning mechanism, charges are separated directly during this primary electron transfer process, yielding hot conduction band electrons in the semiconductor and positive holes localized on oxidized dye molecules at the surface. Comparing results of ultrafast transien...

  20. Stability and charge separation of different CH3NH3SnI3/TiO2 interface: A first-principles study

    Science.gov (United States)

    Yang, Zhenzhen; Wang, Yuanxu; Liu, Yunyan

    2018-05-01

    Interface has an important effect on charge separation of perovskite solar cells. Using first-principles calculations, we studied several different interfaces between CH3NH3SnI3 and TiO2. The interfacial structure and electronic structure of these interfaces are thoroughly explored. We found that the SnI2/anatase (SnI2/A) system is more stable than the other three systems, because an anatase surface can make Snsbnd I bond faster restore to the pristine value than a rutile surface, and SnI2/A system has a smaller standard deviation. The calculated plane-averaged electrostatic potential and the density of states suggest that SnI2/anatase interface has a better separation of photo-generated electron-hole pairs.

  1. Constraints on effective interactions imposed by antisymmetry and charge independence

    Energy Technology Data Exchange (ETDEWEB)

    Stringari, S [Trento Univ. (Italy). Dipartimento di Matematica e Fisica; Brink, D M [Oxford Univ. (UK). Dept. of Theoretical Physics

    1978-07-24

    Restrictions on the form of the energy functional following antisymmetry and charge independence have been investigated for a Hartree-Fock theory based on effective interactions. These restrictions impose severe constraints on density dependent effective interactions.

  2. Pathways and timescales of primary charge separation in the photosystem II reaction center as revealed by a simultaneous fit of time-resolved fluorescence and transient absorption

    NARCIS (Netherlands)

    Novoderezhkin, V.I.; Andrizhiyevskaya, E.G.; Dekker, J.P.; van Grondelle, R.

    2005-01-01

    We model the dynamics of energy transfer and primary charge separation in isolated photosystem II (PSII) reaction centers. Different exciton models with specific site energies of the six core pigments and two peripheral chlorophylls (Chls) in combination with different charge transfer schemes have

  3. Polarization Energies at Organic–Organic Interfaces: Impact on the Charge Separation Barrier at Donor–Acceptor Interfaces in Organic Solar Cells

    KAUST Repository

    Ryno, Sean; Fu, Yao-Tsung; Risko, Chad; Bredas, Jean-Luc

    2016-01-01

    more stabilized at the interface and the Coulomb attraction between the charges, results in a barrier to charge separation at the pentacene-C60 interface that can be in excess of 0.7 eV for static configurations of the donor and acceptor locations

  4. Anisotropic Metal Deposition on TiO2 Particles by Electric-Field-Induced Charge Separation.

    Science.gov (United States)

    Tiewcharoen, Supakit; Warakulwit, Chompunuch; Lapeyre, Veronique; Garrigue, Patrick; Fourier, Lucas; Elissalde, Catherine; Buffière, Sonia; Legros, Philippe; Gayot, Marion; Limtrakul, Jumras; Kuhn, Alexander

    2017-09-11

    Deposition of metals on TiO 2 semiconductor particles (M-TiO 2 ) results in hybrid Janus objects combining the properties of both materials. One of the techniques proposed to generate Janus particles is bipolar electrochemistry (BPE). The concept can be applied in a straightforward way for the site-selective modification of conducting particles, but is much less obvious to use for semiconductors. Herein we report the bulk synthesis of anisotropic M-TiO 2 particles based on the synergy of BPE and photochemistry, allowing the intrinsic limitations, when they are used separately, to be overcome. When applying electric fields during irradiation, electrons and holes can be efficiently separated, thus breaking the symmetry of particles by modifying them selectively and in a wireless way on one side with either gold or platinum. Such hybrid materials are an important first step towards high-performance designer catalyst particles, for example for photosplitting of water. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Charges for plastic bags : Motivational and behavioral effects

    NARCIS (Netherlands)

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

    2014-01-01

    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

  6. Visible-light-driven TiO2/Ag3PO4/GO heterostructure photocatalyst with dual-channel for photo-generated charges separation

    International Nuclear Information System (INIS)

    Lu, Bingqing; Ma, Ni; Wang, Yaping; Qiu, Yiwei; Hu, Haihua; Zhao, Jiahuan; Liang, Dayu; Xu, Sheng; Li, Xiaoyun; Zhu, Zhiyan; Cui, Can

    2015-01-01

    Highlights: • TiO 2 /Ag 3 PO 4 /GO was synthesized with a facile two-step method. • TiO 2 /Ag 3 PO 4 /GO exhibit superior photocatalytic activity and stability. • TiO 2 /Ag 3 PO 4 /GO has dual-channel for photo-generated charges separation. • TiO 2 /Ag 3 PO 4 /GO composite reduces the consumption of Ag. - Abstract: A novel triple-component TiO 2 /Ag 3 PO 4 /graphene oxide (TiO 2 /Ag 3 PO 4 /GO) photocatalyst with dual channels for photo-generated charges separation has been synthesized to improve the photocatalytic activity and stability of Ag 3 PO 4 under visible light. The synthesis involved in-situ growth of Ag 3 PO 4 nanoparticles on GO sheets to form Ag 3 PO 4 /GO, and then deposited TiO 2 nanocrystals on the surface of Ag 3 PO 4 by hydrolysis of Ti(SO 4 ) 2 at low-temperature hydrothermal condition. The TiO 2 /Ag 3 PO 4 /GO exhibited superior photocatalytic activity and stability to bare Ag 3 PO 4 , TiO 2 /Ag 3 PO 4 and Ag 3 PO 4 /GO in degradation of Rhodamine B and phenol solutions under visible light. It is suggested that the photo-generated electrons in the conduction band of Ag 3 PO 4 can be quickly transferred to GO, while the holes in the valence band of Ag 3 PO 4 can be transferred to the valence band of TiO 2 . The dual transfer channels at the interfaces of TiO 2 /Ag 3 PO 4 /GO result in effective charges separation, leading to enhanced photocatalytic activity and stability. Furthermore, the content of noble metal Ag significantly reduces from 77 wt% in bare Ag 3 PO 4 to 55 wt% in the nanocomposite. The concept of establishing dual channels for charges separation in a triple-component heterostructure provides a promising way to develop photocatalysts with high efficiency

  7. Memory properties and charge effect study in Si nanocrystals by scanning capacitance microscopy and spectroscopy

    Directory of Open Access Journals (Sweden)

    Bassani Franck

    2011-01-01

    Full Text Available Abstract In this letter, isolated Si nanocrystal has been formed by dewetting process with a thin silicon dioxide layer on top. Scanning capacitance microscopy and spectroscopy were used to study the memory properties and charge effect in the Si nanocrystal in ambient temperature. The retention time of trapped charges injected by different direct current (DC bias were evaluated and compared. By ramp process, strong hysteresis window was observed. The DC spectra curve shift direction and distance was observed differently for quantitative measurements. Holes or electrons can be separately injected into these Si-ncs and the capacitance changes caused by these trapped charges can be easily detected by scanning capacitance microscopy/spectroscopy at the nanometer scale. This study is very useful for nanocrystal charge trap memory application.

  8. Charge- and Size-Selective Molecular Separation using Ultrathin Cellulose Membranes

    KAUST Repository

    Puspasari, Tiara

    2016-08-30

    To date, it is still a challenge to prepare high-flux and highselectivity microporous membranes thinner than 20 nm without introducing defects. In this work, we report for the first time the application of cellulose membranes for selective separation of small molecules. A freestanding cellulose membrane as thin as 10 nm has been prepared through regeneration of trimethylsilyl cellulose (TMSC). The freestanding membrane can be transferred to any desired substrate and shows a normalized flux as high as 700 L m−2 h−1 bar−1 when supported by a porous alumina disc. According to filtration experiments, the membrane exhibits precise size-sieving performances with an estimated pore size between 1.5–3.5 nm depending on the regeneration period and initial TMSC concentration. A perfect discrimination of anionic molecules over neutral species is demonstrated. Moreover, the membrane demonstrates high reproducibility, high scale-up potential, and excellent stability over two months.

  9. Strong coupling electrostatics for randomly charged surfaces: antifragility and effective interactions.

    Science.gov (United States)

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

    2015-05-07

    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

  10. Study of space--charge effect by computer

    International Nuclear Information System (INIS)

    Sasaki, T.

    1982-01-01

    The space--charge effect in high density electron beams (beam current approx.2 μA) focused by a uniform magnetic field is studied computationally. On an approximation of averaged space-- charge force, a theory of trajectory displacements of beam electrons is developed. The theory shows that the effect of the averaged space--charge force appears as a focal length stretch. The theory is confirmed not only qualitatively but also quantitatively by simulations. Empirical formulas for the trajectory displacement and the energy spread are presented. A comparison between the empirical formulas and some theoretical formulas is made, leading to a severe criticism on the theories of energy spreads

  11. Mergers in the GB Electricity Market: effects on Retail Charges

    International Nuclear Information System (INIS)

    Salies, Evens

    2006-05-01

    The opening up of the UK residential electricity sector in 1999 prompted several studies of the impact this had on both the level and structuring of retail charges, and on incumbent players' market power. Drawing on observations of regional tariffs for the month of January 2004, this paper supports previous conclusions based on simulated retail charges, looking at the response of real tariffs to distribution and transmission costs, customer density, and the length of low voltage underground circuit. We also investigate whether vertically integrated suppliers have a particular effect on charges ceteris paribus the effect of cost drivers and supplier-related factors. (author)

  12. Effective Area and Charge Density of Iridium Oxide Neural Electrodes

    International Nuclear Information System (INIS)

    Harris, Alexander R.; Paolini, Antonio G.; Wallace, Gordon G.

    2017-01-01

    The effective electrode area and charge density of iridium metal and anodically activated iridium has been measured by optical and electrochemical techniques. The degree of electrode activation could be assessed by changes in electrode colour. The reduction charge, activation charge, number of activation pulses and charge density were all strongly correlated. Activated iridium showed slow electron transfer kinetics for reduction of a dissolved redox species. At fast voltammetric scan rates the linear diffusion electroactive area was unaffected by iridium activation. At slow voltammetric scan rates, the steady state diffusion electroactive area was reduced by iridium activation. The steady state current was consistent with a ring electrode geometry, with lateral resistance reducing the electrode area. Slow electron transfer on activated iridium would require a larger overpotential to reduce or oxidise dissolved species in tissue, limiting the electrodes charge capacity but also reducing the likelihood of generating toxic species in vivo.

  13. Effect of Stochastic Charge Fluctuations on Dust Dynamics

    Science.gov (United States)

    Matthews, Lorin; Shotorban, Babak; Hyde, Truell

    2017-10-01

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

  14. Space-Charge Effects in a Gas Detector

    Energy Technology Data Exchange (ETDEWEB)

    Ryutov, D.D.

    2010-12-03

    Discussion of space-charge effects in a photoluminescence cell that will be used as a nondisruptive total energy monitor at the LCLS facility is presented. Regimes where primary photoelectrons will be confined within the X-ray beam aperture are identified. Effects of the space-charge on the further evolution of the electron and ion populations are discussed. Parameters of the afterglow plasma are evaluated. Conditions under which the detector output will be proportional to the pulse energy are defined.

  15. Thermal Bridge Effects in Walls Separating Rowhouses

    DEFF Research Database (Denmark)

    Rose, Jørgen

    1997-01-01

    In this report the thermal bridge effects at internal wall/roof junctions in rowhouses are evaluated. The analysis is performed using a numerical calculation programme, and different solutions are evaluated with respect to extra heat loss and internal surface temperatures.......In this report the thermal bridge effects at internal wall/roof junctions in rowhouses are evaluated. The analysis is performed using a numerical calculation programme, and different solutions are evaluated with respect to extra heat loss and internal surface temperatures....

  16. Maximized Effective Energy Output of Contact-Separation-Triggered Triboelectric Nanogenerators as Limited by Air Breakdown

    KAUST Repository

    Zi, Yunlong; Wu, Changsheng; Ding, Wenbo; Wang, Zhong Lin

    2017-01-01

    Recent progress in triboelectric nanogenerators (TENGs) has demonstrated their promising potential as a high-efficiency mechanical energy harvesting technology, and plenty of effort has been devoted to improving the power output by maximizing the triboelectric surface charge density. However, due to high-voltage air breakdown, most of the enhanced surface charge density brought by material/surface optimization or external ion injection is not retainable or usable for electricity generation during the operation of contact-separation-triggered TENGs. Here, the existence of the air breakdown effect in a contact-separation mode TENG with a low threshold surface charge density of ≈40–50 µC m−2 is first validated under the high impedance external load, and then followed by the theoretical study of the maximized effective energy output as limited by air breakdown for contact-separation-triggered TENGs. The effects of air pressure and gas composition are also studied and propose promising solutions for reducing the air breakdown effect. This research provides a crucial fundamental study for TENG technology and its further development and applications.

  17. Maximized Effective Energy Output of Contact-Separation-Triggered Triboelectric Nanogenerators as Limited by Air Breakdown

    KAUST Repository

    Zi, Yunlong

    2017-05-02

    Recent progress in triboelectric nanogenerators (TENGs) has demonstrated their promising potential as a high-efficiency mechanical energy harvesting technology, and plenty of effort has been devoted to improving the power output by maximizing the triboelectric surface charge density. However, due to high-voltage air breakdown, most of the enhanced surface charge density brought by material/surface optimization or external ion injection is not retainable or usable for electricity generation during the operation of contact-separation-triggered TENGs. Here, the existence of the air breakdown effect in a contact-separation mode TENG with a low threshold surface charge density of ≈40–50 µC m−2 is first validated under the high impedance external load, and then followed by the theoretical study of the maximized effective energy output as limited by air breakdown for contact-separation-triggered TENGs. The effects of air pressure and gas composition are also studied and propose promising solutions for reducing the air breakdown effect. This research provides a crucial fundamental study for TENG technology and its further development and applications.

  18. Early Bacteriopheophytin Reduction in Charge Separation in Reaction Centers of Rhodobacter sphaeroides

    NARCIS (Netherlands)

    Zhu, J.; van Stokkum, I.H.M.; Paparelli, L.; Jones, M.R.; Groot, M.L.

    2013-01-01

    A question at the forefront of biophysical sciences is, to what extent do quantum effects and protein conformational changes play a role in processes such as biological sensing and energy conversion? At the heart of photosynthetic energy transduction lie processes involving ultrafast energy and

  19. Digitally grown AlInAsSb for high gain separate absorption, grading, charge, and multiplication avalanche photodiodes

    Science.gov (United States)

    Lyu, Yuexi; Han, Xi; Sun, Yaoyao; Jiang, Zhi; Guo, Chunyan; Xiang, Wei; Dong, Yinan; Cui, Jie; Yao, Yuan; Jiang, Dongwei; Wang, Guowei; Xu, Yingqiang; Niu, Zhichuan

    2018-01-01

    We report on the growth of high quality GaSb-based AlInAsSb quaternary alloy by molecular beam epitaxy (MBE) to fabricate avalanche photodiodes (APDs). By means of high resolution X-ray diffraction (HRXRD) and scanning transmission electron microscope (STEM), phase separation phenomenon of AlInAsSb random alloy with naturally occurring vertical superlattice configuration was demonstrated. To overcome the tendency for phase segregation while maintaining a highly crystalline film, a digital alloy technique with migration-enhanced epitaxy growth method was employed, using a shutter sequence of AlSb, AlAs, AlSb, Sb, In, InAs, In, Sb. AlInAsSb digital alloy has proved to be reproducible and consistent with single phase, showing sharp satellite peaks on HRXRD rocking curve and smooth surface morphology under atomic force microscopy (AFM). Using optimized digital alloy, AlInAsSb separate absorption, grading, charge, and multiplication (SAGCM) APD was grown and fabricated. At room temperature, the device showed high performance with low dark current density of ∼14.1 mA/cm2 at 95% breakdown and maximum stable gain before breakdown as high as ∼200, showing the potential for further applications in optoelectronic devices.

  20. Charged-particle mutagenesis 2. Mutagenic effects of high energy charged particles in normal human fibroblasts

    Science.gov (United States)

    Chen, D. J.; Tsuboi, K.; Nguyen, T.; Yang, T. C.

    1994-01-01

    The biological effects of high Linear Energy Transfer (LET) charged particles are a subject of great concern with regard to the prediction of radiation risk in space. In this report, mutagenic effects of high LET charged particles are quantitatively measured using primary cultures of human skin fibroblasts, and the spectrum of induced mutations are analyzed. The LET of the charged particles ranged from 25 KeV/micrometer to 975 KeV/micrometer with particle energy (on the cells) between 94-603 MeV/u. The X-chromosome linked hypoxanthine guanine phosphoribosyl transferase (hprt) locus was used as the target gene. Exposure to these high LET charged particles resulted in exponential survival curves; whereas, mutation induction was fitted by a linear model. The Relative Biological Effect (RBE) for cell-killing ranged from 3.73 to 1.25, while that for mutant induction ranged from 5.74 to 0.48. Maximum RBE values were obtained at the LET of 150 keV/micrometer. The inactivation cross-section (alpha i) and the action cross-section for mutant induction (alpha m) ranged from 2.2 to 92.0 sq micrometer and 0.09 to 5.56 x 10(exp -3) sq micrometer respectively. The maximum values were obtained by Fe-56 with an LET of 200 keV/micrometer. The mutagenicity (alpha m/alpha i) ranged from 2.05 to 7.99 x 10(exp -5) with the maximum value at 150 keV/micrometer. Furthermore, molecular analysis of mutants induced by charged particles indicates that higher LET beams are more likely to cause larger deletions in the hprt locus.

  1. Charged-particle mutagenesis II. Mutagenic effects of high energy charged particles in normal human fibroblasts

    Science.gov (United States)

    Chen, D. J.; Tsuboi, K.; Nguyen, T.; Yang, T. C.

    1994-01-01

    The biological effects of high LET charged particles are a subject of great concern with regard to the prediction of radiation risk in space. In this report, mutagenic effects of high LET charged particles are quantitatively measured using primary cultures of human skin fibroblasts, and the spectrum of induced mutations are analyzed. The LET of the charged particles ranged from 25 KeV/micrometer to 975 KeV/micrometer with particle energy (on the cells) between 94-603 MeV/u. The X-chromosome linked hypoxanthine guanine phosphoribosyl transferase (hprt) locus was used as the target gene. Exposure to these high LET charged particles resulted in exponential survival curves; whereas, mutation induction was fitted by a linear model. The Relative Biological Effect (RBE) for cell-killing ranged from 3.73 to 1.25, while that for mutant induction ranged from 5.74 to 0.48. Maximum RBE values were obtained at the LET of 150 keV/micrometer. The inactivation cross-section (alpha i) and the action cross-section for mutant induction (alpha m) ranged from 2.2 to 92.0 micrometer2 and 0.09 to 5.56 x 10(-3) micrometer2, respectively. The maximum values were obtained by 56Fe with an LET of 200 keV/micrometer. The mutagenicity (alpha m/alpha i) ranged from 2.05 to 7.99 x 10(-5) with the maximum value at 150 keV/micrometer. Furthermore, molecular analysis of mutants induced by charged particles indicates that higher LET beams are more likely to cause larger deletions in the hprt locus.

  2. Two-terminal charge tunneling: Disentangling Majorana zero modes from partially separated Andreev bound states in semiconductor-superconductor heterostructures

    Science.gov (United States)

    Moore, Christopher; Stanescu, Tudor D.; Tewari, Sumanta

    2018-04-01

    We show that a pair of overlapping Majorana bound states (MBSs) forming a partially separated Andreev bound state (ps-ABS) represents a generic low-energy feature in spin-orbit-coupled semiconductor-superconductor (SM-SC) hybrid nanowire in the presence of a Zeeman field. The ps-ABS interpolates continuously between the "garden variety" ABS, which consists of two MBSs sitting on top of each other, and the topologically protected Majorana zero modes (MZMs), which are separated by a distance given by the length of the wire. The really problematic ps-ABSs consist of component MBSs separated by a distance of the order of the characteristic Majorana decay length ξ , and have nearly zero energy in a significant range of control parameters, such as the Zeeman field and chemical potential, within the topologically trivial phase. Despite being topologically trivial, such ps-ABSs can generate signatures identical to MZMs in local charge tunneling experiments. In particular, the height of the zero-bias conductance peak (ZBCP) generated by ps-ABSs has the quantized value 2 e2/h , and it can remain unchanged in an extended range of experimental parameters, such as Zeeman field and the tunnel barrier height. We illustrate the formation of such low-energy robust ps-ABSs in two experimentally relevant situations: a hybrid SM-SC system consisting of a proximitized nanowire coupled to a quantum dot and the SM-SC system in the presence of a spatially varying inhomogeneous potential. We then show that, unlike local measurements, a two-terminal experiment involving charge tunneling at both ends of the wire is capable of distinguishing between the generic ps-ABSs and the non-Abelian MZMs. While the MZMs localized at the opposite ends of the wire generate correlated differential conduction spectra, including correlations in energy splittings and critical Zeeman fields associated with the emergence of the ZBCPs, such correlations are absent if the ZBCPs are due to ps-ABSs emerging in the

  3. Simulation of the dielectric charging-up effect in a GEM detector

    International Nuclear Information System (INIS)

    Alfonsi, M.; Croci, G.; Duarte Pinto, S.; Rocco, E.; Ropelewski, L.; Sauli, F.; Veenhof, R.; Villa, M.

    2012-01-01

    The charging up effect is well-known in detectors containing dielectric materials and it is due to electrons and ions liberated in an avalanche and collected on the dielectric surfaces. In particular in Gas Electron Multiplier (GEM) based detectors, charges can be captured by the Kapton that separates top and bottom electrodes. The collection of a substantial number of charges on the dielectric surfaces induces a modification of the field inside the GEM holes that implies important consequences on some fundamental parameters such as the electron transparency and the effective gain. The correct simulation of this effect opens new ways to the detailed study of the processes that happens in a GEM-based detector and gives the possibility to optimise the GEM geometry in order to avoid it. This paper compares results of the measurements and the simulations, with and without the introduction of the charging-up effect, of the GEM electron transparency in the case of a single GEM detector. The introduction of the charging up effect in the simulation resulted to be crucial in order to get the proper agreement with the measurements. The measurements and simulations of the GEM effective gain will be the subject of a future work.

  4. Nonlinear waves in electron-positron-ion plasmas including charge separation

    Science.gov (United States)

    Mugemana, A.; Moolla, S.; Lazarus, I. J.

    2017-02-01

    Nonlinear low-frequency electrostatic waves in a magnetized, three-component plasma consisting of hot electrons, hot positrons and warm ions have been investigated. The electrons and positrons are assumed to have Boltzmann density distributions while the motion of the ions are governed by fluid equations. The system is closed with the Poisson equation. This set of equations is numerically solved for the electric field. The effects of the driving electric field, ion temperature, positron density, ion drift, Mach number and propagation angle are investigated. It is shown that depending on the driving electric field, ion temperature, positron density, ion drift, Mach number and propagation angle, the numerical solutions exhibit waveforms that are sinusoidal, sawtooth and spiky. The introduction of the Poisson equation increased the Mach number required to generate the waveforms but the driving electric field E 0 was reduced. The results are compared with satellite observations.

  5. Space Charge Effect in the Sheet and Solid Electron Beam

    Science.gov (United States)

    Song, Ho Young; Kim, Hyoung Suk; Ahn, Saeyoung

    1998-11-01

    We analyze the space charge effect of two different types of electron beam ; sheet and solid electron beam. Electron gun simulations are carried out using shadow and control grids for high and low perveance. Rectangular and cylindrical geometries are used for sheet and solid electron beam in planar and disk type cathode. The E-gun code is used to study the limiting current and space charge loading in each geometries.

  6. Antihyperglycemic Effects Of Separate And Composite Extract Of ...

    African Journals Online (AJOL)

    Antihyperglycemic Effects Of Separate And Composite Extract Of Root Of Musa paradisiacal And Leaf Of Coccinia indica In Streptozotocin-Induced Diabetic Male ... We noted that after treatment of aqueous methanolic extract of above plant parts in separate as well as in composite manner at a concentration of 80mg/100g ...

  7. Separation of flip and non-flip parts of np → pn charge exchange at energies Tn = 0,5-2,0 GeV

    International Nuclear Information System (INIS)

    Shindin, R.A.; Gur'ev, D.K.; Morozov, A.A.; Nomofilov, A.A.; Strunov, L.N.

    2011-01-01

    The new 'Delta-Sigma' experimental data on the ratio R dp allowed separating the Flip and Non-Flip parts of the differential cross section of np → pn charge exchange process at the zero angle by the Dean formula. The PSA solutions for the np → np elastic scattering are transformed to the np → pn charge exchange representation using unitary transition, and good agreement is obtained

  8. Adiabatic effective action for vortices in neutral and charged superfluids

    International Nuclear Information System (INIS)

    Hatsuda, M.; Sato, M.; Yahikozawa, S.; Hatsuda, T.

    1996-01-01

    Adiabatic effective action for vortices in neutral and charged superfluids at zero temperature are calculated using the topological Landau-Ginzburg theory recently proposed by Hatsuda, Yahikozawa, Ao and Thouless, and vortex dynamics are examined. The Berry phase term arising in the effective action naturally yields the Magnus force in both neutral and charged superfluids. It is shown that in neutral superfluid there is only one degree of freedom, namely the center of vorticities, and the vortex energy is proportional to the sum of all vorticities so that it is finite only for the vanishing total vorticity of the system. On the other hand the effective mass and the vortex energy for a vortex in charged superfluids are defined individually as expected. The effects of the vortex core on these quantities are also estimated. The possible depinning scenario which is governed by the Magnus force and the inertial mass is also discussed

  9. Streaming effect of wall oscillation to boundary layer separation

    Science.gov (United States)

    Wu, X. H.; Wu, J. Z.; Wu, J. M.

    1991-01-01

    This paper presents a preliminary theoretical result on the time averaged streaming effect of local forcing excitation to the boundary layer separation from smooth surface. The problem is formulated as a periodic disturbance to a basic steady breakaway separating flow, for which the data are taken from a numerical triple-deck solution. The ratio of Strouhal number St and Reynolds number Re plays an important role, both being assumed sufficiently high. The analytical and numerical results show that this streaming effect is quite strong at proper values of St/Re exp 1/4, which may delay or even suppress the separation.

  10. Generalized polymer effective charge measurement by capillary isotachophoresis.

    Science.gov (United States)

    Chamieh, Joseph; Koval, Dušan; Besson, Adeline; Kašička, Václav; Cottet, Hervé

    2014-11-28

    In this work, we have generalized the use of capillary isotachophoresis as a universal method for determination of effective charge of anionic and cationic (co)polymers on ordinary capillary electrophoresis instruments. This method is applicable to a broad range of strong or weak polyelectrolytes with good repeatability. Experimental parameters (components and concentrations of leading and terminating electrolytes, capillary diameters, constant electric current intensity) were optimized for implementation in 100 μm i.d. capillaries for both polyanions and polycations. Determined values of polymer effective charge were in a very good agreement with those obtained by capillary electrophoresis with indirect UV detection. Uncertainty of the effective charge measurement using isotachophoresis was addressed and estimated to be ∼5-10% for solutes with mobilities in the 20-50 × 10(-9)m(2)V(-1)s(-1) range. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Reducing charging effects in scanning electron microscope images by Rayleigh contrast stretching method (RCS).

    Science.gov (United States)

    Wan Ismail, W Z; Sim, K S; Tso, C P; Ting, H Y

    2011-01-01

    To reduce undesirable charging effects in scanning electron microscope images, Rayleigh contrast stretching is developed and employed. First, re-scaling is performed on the input image histograms with Rayleigh algorithm. Then, contrast stretching or contrast adjustment is implemented to improve the images while reducing the contrast charging artifacts. This technique has been compared to some existing histogram equalization (HE) extension techniques: recursive sub-image HE, contrast stretching dynamic HE, multipeak HE and recursive mean separate HE. Other post processing methods, such as wavelet approach, spatial filtering, and exponential contrast stretching, are compared as well. Overall, the proposed method produces better image compensation in reducing charging artifacts. Copyright © 2011 Wiley Periodicals, Inc.

  12. Cyanobacterial flv4-2 Operon-Encoded Proteins Optimize Light Harvesting and Charge Separation in Photosystem II.

    Science.gov (United States)

    Chukhutsina, Volha; Bersanini, Luca; Aro, Eva-Mari; van Amerongen, Herbert

    2015-05-01

    Photosystem II (PSII) complexes drive the water-splitting reaction necessary to transform sunlight into chemical energy. However, too much light can damage and disrupt PSII. In cyanobacteria, the flv4-2 operon encodes three proteins (Flv2, Flv4, and Sll0218), which safeguard PSII activity under air-level CO2 and in high light conditions. However, the exact mechanism of action of these proteins has not been clarified yet. We demonstrate that the PSII electron transfer properties are influenced by the flv4-2 operon-encoded proteins. Accelerated secondary charge separation kinetics was observed upon expression/overexpression of the flv4-2 operon. This is likely induced by docking of the Flv2/Flv4 heterodimer in the vicinity of the QB pocket of PSII, which, in turn, increases the QB redox potential and consequently stabilizes forward electron transfer. The alternative electron transfer route constituted by Flv2/Flv4 sequesters electrons from QB(-) guaranteeing the dissipation of excess excitation energy in PSII under stressful conditions. In addition, we demonstrate that in the absence of the flv4-2 operon-encoded proteins, about 20% of the phycobilisome antenna becomes detached from the reaction centers, thus decreasing light harvesting. Phycobilisome detachment is a consequence of a decreased relative content of PSII dimers, a feature observed in the absence of the Sll0218 protein. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.

  13. Charge Fractionalization in the Two-Channel Kondo Effect

    Science.gov (United States)

    Landau, L. Aviad; Cornfeld, Eyal; Sela, Eran

    2018-05-01

    The phenomenon of charge fractionalization describes the emergence of novel excitations with fractional quantum numbers, as predicted in strongly correlated systems such as spin liquids. We elucidate that precisely such an unusual effect may occur in the simplest possible non-Fermi liquid, the two-channel Kondo effect. To bring this concept down to experimental test, we study nonequilibrium transport through a device realizing the charge two-channel Kondo critical point in a recent experiment by Iftikhar et al. [Nature (London) 526, 233 (2015), 10.1038/nature15384]. The shot noise at low voltages is predicted to result in a universal Fano factor e*/e =1 /2 . This allows us to experimentally identify elementary transport processes of emergent fermions carrying half-integer charge.

  14. Effects of parental separation and divorce on very young children.

    Science.gov (United States)

    Clarke-Stewart, K A; Vandell, D L; McCartney, K; Owen, M T; Booth, C

    2000-06-01

    Data from the National Institute of Child Health and Human Development Study of Early Child Care were analyzed to explore effects of marital separation on children in the first 3 years of life. The sample included 73 never-married mothers and 97 separated mothers; a comparison group of 170 was conditionally randomly selected from the 2-parent families. Children in 2-parent families performed better than children in 1-parent families on assessments of cognitive and social abilities, problem behavior, attachment security, and behavior with mother. However, controlling for mothers' education and family income reduced these differences, and associations with separated-intact marital status were nonsignificant (the effect size was .01). Thus, children's psychological development was not affected by parental separation per se; it was related to mothers' income, education, ethnicity, child-rearing beliefs, depressive symptoms, and behavior.

  15. Antifouling Cellulose Hybrid Biomembrane for Effective Oil/Water Separation.

    Science.gov (United States)

    Kollarigowda, Ravichandran H; Abraham, Sinoj; Montemagno, Carlo D

    2017-09-06

    Oil/water separation has been of great interest worldwide because of the increasingly serious environmental pollution caused by the abundant discharge of industrial wastewater, oil spill accidents, and odors. Here, we describe simple and economical superhydrophobic hybrid membranes for effective oil/water separation. Eco-friendly, antifouling membranes were fabricated for oil/water separation, waste particle filtration, the blocking of thiol-based odor materials, etc., by using a cellulose membrane (CM) filter. The CM was modified from its original superhydrophilic nature into a superhydrophobic surface via a reversible addition-fragmentation chain transfer technique. The block copolymer poly{[3-(trimethoxysilyl)propyl acrylate]-block-myrcene} was synthesized using a "grafting-from" approach on the CM. The surface contact angle that we obtained was >160°, and absorption tests of several organic contaminants (oils and solvents) exhibited superior levels of extractive activity and excellent reusability. These properties rendered this membrane a promising surface for oil/water separation. Interestingly, myrcene blocks thiol (through "-ene-" chemistry) contaminants, thereby bestowing a pleasant odor to polluted water by acting as an antifouling material. We exploited the structural properties of cellulose networks and simple chemical manipulations to fabricate an original material that proved to be effective in separating water from organic and nano/microparticulate contaminants. These characteristics allowed our material to effectively separate water from oily/particulate phases as well as embed antifouling materials for water purification, thus making it an appropriate absorber for chemical processes and environmental protection.

  16. Extension of the charge separated-state lifetime by supramolecular association of a tetrathiafulvalene electron donor to a zinc/gold bisporphyrin.

    Science.gov (United States)

    Boixel, Julien; Fortage, Jérôme; Blart, Errol; Pellegrin, Yann; Hammarström, Leif; Becker, Hans-Christian; Odobel, Fabrice

    2010-02-14

    Supramolecular triads were prepared by self-assembly of 4'-pyridyl-2-tetrathiafulvalene axially bound on ZnP-spacer-AuP(+) dyads; the lifetime of the charge separated state ((+)TTF-ZnP-Spacer-AuP ) formed upon light excitation of the triad is greatly increased with respect to that found in the parent dyad.

  17. The application of the signal flow graph method to charged-particle optics - the formula derivation of a three-sector isotope separator

    International Nuclear Information System (INIS)

    Lu Hongyou; Zhao Zhiyong; Sun Quinren

    1987-01-01

    A brief introduction of the Signal Flow Graph (SFG) method is given. The application of it to charged-particle optics (CPO) is described. The method has the advantages of simplicity, visualisation and computerisation. An example of the application of SFG is given for the design of a three-sector electromagnetic isotope separator. (orig.)

  18. Description of the Charge Transfer States at the Pentacene/C60 Interface: Combining Range-Separated Hybrid Functionals with the Polarizable Continuum Model

    KAUST Repository

    Zheng, Zilong

    2016-06-24

    Density functional theory (DFT) approaches based on range-separated hybrid functionals are currently methods of choice for the description of the charge-transfer (CT) states in organic donor/acceptor solar cells. However, these calculations are usually performed on small-size donor/acceptor complexes and as result do not account for electronic polarization effects. Here, using a pentacene/C60 complex as a model system, we discuss the ability of long-range corrected (LCR) hybrid functionals in combination with the polarizable continuum model (PCM) to determine the impact of the solid-state environment on the CT states. The CT energies are found to be insensitive to the interactions with the dielectric medium when a conventional time-dependent DFT/PCM (TDDFT/PCM) approach is used. However, a decrease in the energy of the CT state in the framework of LRC functionals can be obtained by using a smaller range-separated parameter when going from an isolated donor/acceptor complex to the solid-state case.

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

    Indian Academy of Sciences (India)

    Abstract. The effect of dielectronic recombination in determining charge-state distribu- tion and radiative emission from a laser-produced carbon plasma has been investigated in the collisional radiative ionization equilibrium. It is observed that the relative abundances of different ions in the plasma, and soft X-ray emission ...

  20. Space charge effects in a bending magnet system

    International Nuclear Information System (INIS)

    Lee, E.P.; Close, E.; Smith, L.

    1987-03-01

    In order to examine problems and phenomena associated with space charge in a beam bending system, the beam dynamics code HICURB has been written. Its principal features include momentum variations, vertical and horizontal envelope dynamics coupled to the off-axis centroid, curvature effect on fields, and images. Preliminary results for an achromatic lattice configuration are presented

  1. Space charge effects in a bending magnet system

    International Nuclear Information System (INIS)

    Lee, E.P.; Close, E.; Smith, L.

    1987-01-01

    In order to examine problems and phenomena associated with space charge in a beam bending system, the beam dynamics code HICURB has been written. Its principal features include momentum variations, vertical and horizontal envelope dynamics coupled to the off-axis centroid, curvature effect on fields, and images. Preliminary results for an achromatic lattice configuration are presented

  2. Charge transport in disordered organic field-effect transistors

    NARCIS (Netherlands)

    Tanase, Cristina; Blom, Paul W.M.; Meijer, Eduard J.; Leeuw, Dago M. de; Jabbour, GE; Carter, SA; Kido, J; Lee, ST; Sariciftci, NS

    2002-01-01

    The transport properties of poly(2,5-thienylene vinylene) (PTV) field-effect transistors (FET) have been investigated as a function of temperature under controlled atmosphere. In a disordered semiconductor as PTV the charge carrier mobility, dominated by hopping between localized states, is

  3. Ambipolar charge transport in organic field-effect transistors

    NARCIS (Netherlands)

    Smits, E.C.P.; Anthopoulos, T.D.; Setayesh, S.; Veenendaal, van E.; Coehoorn, R.; Blom, P.W.M.; Boer, de B.; Leeuw, de D.M.

    2006-01-01

    A model describing charge transport in disordered ambipolar organic field-effect transistors is presented. The basis of this model is the variable-range hopping in an exponential density of states developed for disordered unipolar organic transistors. We show that the model can be used to calculate

  4. Space-charge effects in Penning ion traps

    Science.gov (United States)

    Porobić, T.; Beck, M.; 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.

    2015-06-01

    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 K39+ 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.

  5. Spacecraft Charging: Hazard Causes, Hazard Effects, Hazard Controls

    Science.gov (United States)

    Koontz, Steve.

    2018-01-01

    Spacecraft flight environments are characterized both by a wide range of space plasma conditions and by ionizing radiation (IR), solar ultraviolet and X-rays, magnetic fields, micrometeoroids, orbital debris, and other environmental factors, all of which can affect spacecraft performance. Dr. Steven Koontz's lecture will provide a solid foundation in the basic engineering physics of spacecraft charging and charging effects that can be applied to solving practical spacecraft and spacesuit engineering design, verification, and operations problems, with an emphasis on spacecraft operations in low-Earth orbit, Earth's magnetosphere, and cis-Lunar space.

  6. Secondary Electron Emission from Dust and Its Effect on Charging

    Science.gov (United States)

    Saikia, B. K.; Kakati, B.; Kausik, S. S.; Bandyopadhyay, M.

    2011-11-01

    Hydrogen plasma is produced in a plasma chamber by striking discharge between incandescent tungsten filaments and the permanent magnetic cage [1], which is grounded. The magnetic cage has a full line cusped magnetic field geometry used to confine the plasma elements. A cylindrical Langmuir probe is used to study the plasma parameters in various discharge conditions. The charge accumulated on the dust particles is calculated using the capacitance model and the dust current is measured by the combination of a Faraday cup and an electrometer at different discharge conditions. It is found Secondary electron emission from dust having low emission yield effects the charging of dust particles in presence of high energetic electrons.

  7. Secondary Electron Emission from Dust and Its Effect on Charging

    International Nuclear Information System (INIS)

    Saikia, B. K.; Kakati, B.; Kausik, S. S.; Bandyopadhyay, M.

    2011-01-01

    Hydrogen plasma is produced in a plasma chamber by striking discharge between incandescent tungsten filaments and the permanent magnetic cage [1], which is grounded. The magnetic cage has a full line cusped magnetic field geometry used to confine the plasma elements. A cylindrical Langmuir probe is used to study the plasma parameters in various discharge conditions. The charge accumulated on the dust particles is calculated using the capacitance model and the dust current is measured by the combination of a Faraday cup and an electrometer at different discharge conditions. It is found Secondary electron emission from dust having low emission yield effects the charging of dust particles in presence of high energetic electrons.

  8. Effect of geometric parameters of liquid-gas separator units on phase separation performance

    Energy Technology Data Exchange (ETDEWEB)

    Mo, Songping; Chen, Xueqing; Chen, Ying [Guangdong University of Technology, Seoul (China); Yang, Zhen [Tsinghua University, Beijing (China)

    2015-07-15

    Five liquid-gas separator units were designed and constructed based on a new concept of a validated high-performance condenser. Each separator unit consists of two united T-junctions and an apertured baffle. The separator units have different header diameters or different baffles with different diameters of the liquid-gas separation hole. The phase separation characteristics of the units were investigated at inlet air superficial velocities from 1.0m/s to 33.0m/s and water superficial velocities from 0.0015 m/s to 0..50 m/s. The experimental results showed that the liquid height, liquid flow rate through the separation hole, and liquid separation efficiency increased with increased header diameter and decreased diameter of the separation hole. The geometric structures of the separator units affected the phase separation characteristics by influencing the liquid height in the header and the liquid flow rate through the separation hole.

  9. Charging and geometric effects on conduction through Anthracene molecular junctions

    Science.gov (United States)

    Kaur, Rupan Preet; Sawhney, Ravinder Singh; Engles, Derick

    We studied the geometric effects on the charge transfer through the anthracenedithiol (ADT) molecular junction using density functional theory combined with the non-equilibrium Green’s function approach. Two major geometric aspects, bond length and bond angle, were moderated to optimize the electrical conduction. From the results established in this paper, we found that the electrical conduction can be tuned from 0.2 G0 to 0.9 G0 by varying the Au-S bond length, whereas the moderation of bonding angle assayed a minor change from 0.37 G0 to 0.47 G0. We attributed this escalating zero bias conductance to the increasing charge on the terminal sulfur atom of the ADT molecule, which increased the energy of the HOMO orbital towards Fermi level and exhibited a semi-metallic behaviour. Therefore, geometry plays a critical role in deciding the charge transport through the metal/molecule interface.

  10. Rectification effect about vacuum separating carbon nanotube bundle predicted by first-principles study

    Energy Technology Data Exchange (ETDEWEB)

    Min, Y., E-mail: minshiyi@gmail.com [School of Science, Nantong University, Nantong, Jiangsu, 226007 (China); Fang, J.H.; Zhong, C.G. [School of Science, Nantong University, Nantong, Jiangsu, 226007 (China); Yao, K.L. [School of Physics, Huazhong University of Science and Technology, Wuhan, 430074 (China)

    2012-05-07

    For the molecular spintronics transport systems, we propose that the spin current rectifier can be constructed using the nonmagnetic lead. The proposal is confirmed according to the first-principles study of the transport characteristics of a vacuum separating (15,0) carbon nanotube bundle where only one zigzag edge is hydrogenated. The strong rectification effect for spin (charge) current is obtained in the case of the magnetic parallel (anti-parallel) configuration of two zigzag edges. Our investigations indicate that such device can be used as the spin filter and the counterpart of the p–n junction in the field of molecular electronics. -- Highlights: ► We propose that nonmagnetic leads can construct spin current rectifier. ► We propose a spin diode and a filter using CNT. ► The spin and charge current all have the rectification effect in the one-dimensional spin diode.

  11. Effects of laminar separation bubbles and turbulent separation on airfoil stall

    Energy Technology Data Exchange (ETDEWEB)

    Dini, P. [Carleton College, Northfield, MN (United States); Coiro, D.P. [Universita di Napoli (Italy)

    1997-12-31

    An existing two-dimensional, interactive, stall prediction program is extended by improving its laminar separation bubble model. The program now accounts correctly for the effects of the bubble on airfoil performance characteristics when it forms at the mid-chord and on the leading edge. Furthermore, the model can now predict bubble bursting on very sharp leading edges at high angles of attack. The details of the model are discussed in depth. Comparisons of the predicted stall and post-stall pressure distributions show excellent agreement with experimental measurements for several different airfoils at different Reynolds numbers.

  12. Equilibrium charge fluctuations of a charge detector and its effect on a nearby quantum dot

    Science.gov (United States)

    Ruiz-Tijerina, David; Vernek, Edson; Ulloa, Sergio

    2014-03-01

    We study the Kondo state of a spin-1/2 quantum dot (QD), in close proximity to a quantum point contact (QPC) charge detector near the conductance regime of the 0.7 anomaly. The electrostatic coupling between the QD and QPC introduces a remote gate on the QD level, which varies with the QPC gate voltage. Furthermore, models for the 0.7 anomaly [Y. Meir et al., PRL 89,196802(2002)] suggest that the QPC lodges a Kondo-screened level with charge-correlated hybridization, which may be also affected by capacitive coupling to the QD, giving rise to a competition between the two Kondo ground states. We model the QD-QPC system as two capacitively-coupled Kondo impurities, and explore the zero-bias transport of both the QD and the QPC for different local gate voltages and coupling strengths, using the numerical renormalization group and variational methods. We find that the capacitive coupling produces a remote gating effect, non-monotonic in the gate voltages, which reduces the gate voltage window for Kondo screening in either impurity, and which can also drive a quantum phase transition out of the Kondo regime. Our study is carried out for intermediate coupling strengths, and as such is highly relevant to experiments; particularly, to recent studies of decoherence effects on QDs. Supported by MWN/CIAM and NSF PIRE.

  13. Peltier effect in multilayered nanopillars under high density charge current

    International Nuclear Information System (INIS)

    Gravier, L; Fukushima, A; Kubota, H; Yamamoto, A; Yuasa, S

    2006-01-01

    From the basic equations of thermoelectricity, we model the thermal regimes that develop in multilayered nanopillar elements experiencing continuous charge currents. The energy conservation principle was applied to all layer-layer and layer-electrode junctions. The obtained set of equations was solved to derive the temperature of each junction. The contribution of the Peltier effect is included in an effective resistance. This model gives satisfactory fits to experimental data obtained on a series of reference nanopillar elements

  14. Effectiveness Evaluation for a Commercialized PV-Assisted Charging Station

    Directory of Open Access Journals (Sweden)

    Nian Liu

    2017-02-01

    Full Text Available The Photovoltaic–assisted Charging Station (PVCS is regarded as one of the most promising charging facilities for future electric vehicle (EV energy supplementation. In this paper, the operation mode and profitability of a commercialized PVCS are analyzed under the energy policy of China. In order to evaluate the long-term effectiveness of using the PVCS to provide guidance for the investors of the stations, a set of evaluation indexes is introduced, including the quality of service, the environmental and economic benefits, and the impacts on the grid. Furthermore, an easily-achieved charging strategy which considers the quality of service and the self-consumption of PV energy is proposed. Finally, an effectiveness evaluation for different operational scenarios of the PVCS is completed, based on the actual statistical data. The simulation and evaluation results indicate that the PVCS has the potential to produce satisfactory environmental/economic benefits and to reduce the impacts and dependence of an EV’s charging load on the grid.

  15. Effects of fibre dimension and charge density on nanocellulose gels.

    Science.gov (United States)

    Mendoza, Llyza; Gunawardhana, Thilina; Batchelor, Warren; Garnier, Gil

    2018-04-18

    Carboxylated cellulose nanofibres can produce gels at low concentrations. The effect of pulp source on the nanocellulose fibre dimension and gel rheology are studied. It is hypothesised that fibre length and surface charge influence aspects of the gel rheological properties. TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl)- mediated oxidised cellulose nanofibres from never-dried hardwood and softwood pulp and containing different charge levels were produced and characterized. Steady-state and dynamic rheological studies were performed to ascertain the effects of pulp type on gel behavior and properties. Nanocellulose fibres extracted from softwood (SW-TOCN) and hardwood (HW-TOCN) pulp exhibit similar widths but different length dimensions as shown via AFM analysis. Rheological measurements show that the dynamic moduli (G' and G'') of nanocellulose gels are independent of pulp source and are mostly influenced by fibre concentration. Differences in the steady-state behavior (i.e. viscosity) at constant surface charge can be attributed to differences in fibre length. Increasing the surface charge density influences the critical strain and the viscosity at the percolation concentration (0.1 wt%) due to higher electrostatic interactions. Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.

  16. Determination of effective charges and ionic mobilities of polycationic antimicrobial peptides by capillary isotachophoresis and capillary zone electrophoresis

    Czech Academy of Sciences Publication Activity Database

    Tůmová, Tereza; Monincová, Lenka; Nešuta, Ondřej; Čeřovský, Václav; Kašička, Václav

    2017-01-01

    Roč. 38, č. 16 (2017), s. 2018-2024 ISSN 0173-0835 R&D Projects: GA ČR(CZ) GA15-01948S Institutional support: RVO:61388963 Keywords : antimicrobial peptides * capillary isotachophoresis * counterion condensation * effective charge * ionic mobility Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 2.744, year: 2016

  17. Long-Lived Photoinduced Charge Separation in a Trinuclear Iron-μ 3 -oxo-based Metal–Organic Framework

    Energy Technology Data Exchange (ETDEWEB)

    Hanna, Lauren [Department; Kucheryavy, Pavel [Department; Liu, Cunming [X-ray; Zhang, Xiaoyi [X-ray; Lockard, Jenny V. [Department

    2017-06-14

    The presence of long-lived charge-separated excited states in metal-organic frameworks (MOFs) can enhance their photocatalytic activity by decreasing the probability that photogenerated electrons and holes recombine before accessing adsorbed reactants. Detecting these charge separated states via optical transient absorption, however, can be challenging when they lack definitive optical signatures. Here, we investigate the long-lived excited state of a MOF with such vague optical properties, MIL-100(Fe), comprised of Fe3-μ3-oxo clusters and trimesic acid linkers using Fe K-edge X-ray transient absorption (XTA) spectroscopy, to unambiguously determine its ligand-to-metal charge transfer character. Spectra measured at time delays up to 3.6 μs confirm the long lived nature of the charge separated excited state. Several trinuclear iron μ3- oxo carboxylate complexes, which model the trinuclear cores of the MOF structure, are measured for comparison using both steady state XAS and XTA to further support this assignment and corresponding decay time. The MOF is prepared as a colloidal nanoparticle suspension for these measurements so both its fabrication and particle size analysis are presented, as well.

  18. Final Technical Report for the Energy Frontier Research Center Understanding Charge Separation and Transfer at Interfaces in Energy Materials (EFRC:CST)

    Energy Technology Data Exchange (ETDEWEB)

    Vanden Bout, David A. [Univ. of Texas, Austin, TX (United States)

    2015-09-14

    Our EFRC was founded with the vision of creating a broadly collaborative and synergistic program that would lead to major breakthroughs in the molecular-level understanding of the critical interfacial charge separation and charge transfer (CST) processes that underpin the function of candidate materials for organic photovoltaic (OPV) and electrical-energy-storage (EES) applications. Research in these energy contexts shares an imposing challenge: How can we understand charge separation and transfer mechanisms in the presence of immense materials complexity that spans multiple length scales? To address this challenge, our 50-member Center undertook a total of 28 coordinated research projects aimed at unraveling the CST mechanisms that occur at interfaces in these nanostructured materials. This rigorous multi-year study of CST interfaces has greatly illuminated our understanding of early-timescale processes (e.g., exciton generation and dissociation dynamics at OPV heterojunctions; control of Li+-ion charging kinetics by surface chemistry) occurring in the immediate vicinity of interfaces. Program outcomes included: training of 72 graduate student and postdoctoral energy researchers at 5 institutions and spanning 7 academic disciplines in science and engineering; publication of 94 peer-reviewed journal articles; and dissemination of research outcomes via 340 conference, poster and other presentations. Major scientific outcomes included: implementation of a hierarchical strategy for understanding the electronic communication mechanisms and ultimate fate of charge carriers in bulk heterojunction OPV materials; systematic investigation of ion-coupled electron transfer processes in model Li-ion battery electrode/electrolyte systems; and the development and implementation of 14 unique technologies and instrumentation capabilities to aid in probing sub-ensemble charge separation and transfer mechanisms.

  19. Transient and modulated charge separation at CuInSe{sub 2}/C{sub 60} and CuInSe{sub 2}/ZnPc hybrid interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Morzé, Natascha von, E-mail: natascha.von_morze@helmholtz-berlin.de; Dittrich, Thomas, E-mail: dittrich@helmholtz-berlin.de; Calvet, Wolfram, E-mail: wolfram.calvet@helmholtz-berlin.de; Lauermann, Iver, E-mail: iver.lauermann@helmholtz-berlin.de; Rusu, Marin, E-mail: rusu@helmholtz-berlin.de

    2017-02-28

    Highlights: • Surface physical properties of non- and Na-treated CuInSe{sub 2} layers studied. • Evidence of exciton dissociation and charge separation at CuInSe{sub 2}/ZnPc interface. • Strong band bending at the CuInSe{sub 2} surface in contact with C{sub 60} observed. • No evidence for exciton dissociation at the CuInSe{sub 2}/C{sub 60} interface found. • Cu-poor phase at CuInSe{sub 2}/organic interface crucial for charge separation. - Abstract: Spectral dependent charge transfer and exciton dissociation have been investigated at hybrid interfaces between inorganic polycrystalline CuInSe{sub 2} (untreated and Na-conditioned) thin films and organic C{sub 60} as well as zinc phthalocyanine (ZnPc) layers by transient and modulated surface photovoltage measurements. The stoichiometry and electronic properties of the bare CuInSe{sub 2} surface were characterized by photoelectron spectroscopy which revealed a Cu-poor phase with n-type features. After the deposition of the C{sub 60} layer, a strong band bending at the CuInSe{sub 2} surface was observed. Evidence for dissociation of excitons followed by charge separation was found at the CuInSe{sub 2}/ZnPc interface. The Cu-poor layer at the CuInSe{sub 2} surface was found to be crucial for transient and modulated charge separation at CuInSe{sub 2}/organic hybrid interfaces.

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

    Science.gov (United States)

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

    2010-04-01

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

  1. Isotope effect and isotope separation. A chemist's view

    International Nuclear Information System (INIS)

    Ishida, Takanobu

    2002-01-01

    What causes the isotope effects (IE)? This presentation will be centered around the equilibrium isotope effects due to the differences in the nuclear masses. The occurrence of the equilibrium constant, K, of isotope exchange reactions which differ from the values predicted by the classical theory of statistical mechanics, K cl , is explored. The non-classical K corresponds to the unit-stage separation factor, α, that is different from unity and forms a basis of an isotope separation process involving the chemical exchange reaction. Here, the word 'chemical exchange' includes not only the isotope exchange chemical reactions between two or more chemical species but also the isotope exchanges involving the equilibria between liquid and vapor phases and liquid-gas, liquid solution-gas, liquid-liquid, and solid-liquid phases. In Section I, origins of the isotope effect phenomena will be explored and, in the process, various quantities used in discussions of isotope effect that have often caused confusions will be unambiguously defined. This Section will also correlate equilibrium constant with separation factor. In Section II, various forms of temperature-dependence of IE and separation factor will be discussed. (author)

  2. Geometrical effects on the airfoil flow separation and transition

    KAUST Repository

    Zhang, Wei; Cheng, Wan; Gao, Wei; Qamar, Adnan; Samtaney, Ravi

    2015-01-01

    We present results from direct numerical simulations (DNS) of incompressible flow over two airfoils, NACA-4412 and NACA-0012-64, to investigate the effects of the airfoil geometry on the flow separation and transition patterns at Re=104 and 10

  3. Coupling of electric charge and magnetic field via electronic phase separation in (La,Pr,Ca)MnO3/Pb(Mg1/3Nb2/3)O3-PbTiO3 multiferroic heterostructures

    Science.gov (United States)

    Zheng, Ming; Wang, Wei

    2016-04-01

    The electric-field-tunable non-volatile resistivity and ferromagnetism switching in the (La0.5Pr0.5)0.67Ca0.33MnO3 films grown on (111)-oriented 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 ferroelectric single-crystal substrates have been investigated. By combining the 180° ferroelectric domain switching and in situ X-ray diffraction and resistivity measurements, we identify that this voltage control of order parameters stems from the domain switching-induced accumulation/depletion of charge carriers at the interface rather than induced lattice strain effect. In particular, the polarization-induced charge effect (i.e., ferroelectric field effect) is strongly dependent on the magnetic field. This, together with the charge-modulated magnetoresistance and magnetization, reveals the strong correlation between the electric charge and the magnetic field. Further, we found that this coupling is essentially driven by the electronic phase separation, the relative strength of which could be determined by recording charge-tunability of resistivity [ (Δρ/ρ)c h arg e ] under various magnetic fields. These findings present a potential strategy for elucidating essential physics of perovskite manganites and delivering prototype electronic devices for non-volatile information storage.

  4. A Novel, In-solution Separation of Endogenous Cardiac Sarcomeric Proteins and Identification of Distinct Charged Variants of Regulatory Light Chain*

    Science.gov (United States)

    Scruggs, Sarah B.; Reisdorph, Rick; Armstrong, Mike L.; Warren, Chad M.; Reisdorph, Nichole; Solaro, R. John; Buttrick, Peter M.

    2010-01-01

    The molecular conformation of the cardiac myosin motor is modulated by intermolecular interactions among the heavy chain, the light chains, myosin binding protein-C, and titin and is governed by post-translational modifications (PTMs). In-gel digestion followed by LC/MS/MS has classically been applied to identify cardiac sarcomeric PTMs; however, this approach is limited by protein size, pI, and difficulties in peptide extraction. We report a solution-based work flow for global separation of endogenous cardiac sarcomeric proteins with a focus on the regulatory light chain (RLC) in which specific sites of phosphorylation have been unclear. Subcellular fractionation followed by OFFGEL electrophoresis resulted in isolation of endogenous charge variants of sarcomeric proteins, including regulatory and essential light chains, myosin heavy chain, and myosin-binding protein-C of the thick filament. Further purification of RLC using reverse-phase HPLC separation and UV detection enriched for RLC PTMs at the intact protein level and provided a stoichiometric and quantitative assessment of endogenous RLC charge variants. Digestion and subsequent LC/MS/MS unequivocally identified that the endogenous charge variants of cardiac RLC focused in unique OFFGEL electrophoresis fractions were unphosphorylated (78.8%), singly phosphorylated (18.1%), and doubly phosphorylated (3.1%) RLC. The novel aspects of this study are that 1) milligram amounts of endogenous cardiac sarcomeric subproteome were focused with resolution comparable with two-dimensional electrophoresis, 2) separation and quantification of post-translationally modified variants were achieved at the intact protein level, 3) separation of intact high molecular weight thick filament proteins was achieved in solution, and 4) endogenous charge variants of RLC were separated; a novel doubly phosphorylated form was identified in mouse, and singly phosphorylated, singly deamidated, and deamidated/phosphorylated forms were

  5. 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 ...

  6. The Crowding-Out Effects of Garbage Fees and Voluntary Source Separation Programs on Waste Reduction: Evidence from China

    Directory of Open Access Journals (Sweden)

    Hongyun Han

    2016-07-01

    Full Text Available This paper examines how and to what degree government policies of garbage fees and voluntary source separation programs, with free indoor containers and garbage bags, can affect the effectiveness of municipal solid waste (MSW management, in the sense of achieving a desirable reduction of per capita MSW generation. Based on city-level panel data for years 1998–2012 in China, our empirical analysis indicates that per capita MSW generated is increasing with per capita disposable income, average household size, education levels of households, and the lagged per capita MSW. While both garbage fees and source separation programs have separately led to reductions in per capita waste generation, the interaction of the two policies has resulted in an increase in per capita waste generation due to the following crowding-out effects: Firstly, the positive effect of income dominates the negative effect of the garbage fee. Secondly, there are crowding-out effects of mandatory charging system and the subsidized voluntary source separation on per capita MSW generation. Thirdly, small subsidies and tax punishments have reduced the intrinsic motivation for voluntary source separation of MSW. Thus, compatible fee charging system, higher levels of subsidies, and well-designed public information and education campaigns are required to promote household waste source separation and reduction.

  7. Analysis of beam envelope by transverse space charge effect

    International Nuclear Information System (INIS)

    Toyama, Shin'ichi

    1997-09-01

    It is important for high current accelerators to estimate the contribution of the space charge effect to keep the beam off its beak up. The application of an envelope equation is examined in previous report in which the beam is just coasting beam (non accelerating). The analysis of space charge effect is necessary for the comparison in coming accelerator test in PNC. In order to evaluate the beam behavior in high current, the beam dynamics and beam parameters which are input to the equation for the evaluation are developed and make it ready to estimate the beam transverse dynamics by the space charge. The estimate needs to have enough accuracy for advanced code calculation. After the preparation of the analytic expression of transverse motion, the non-linear differential equation of beam dynamics is solved by a numerical method on a personal computer. The beam envelope from the equation is estimated by means of the beam emittance, current and energy. The result from the analysis shows that the transverse beam broadening is scarecely small around the beam current value of PNC design. The contribution to the beam broadening of PNC linac comes from its beam emittance. The beam broadening in 100 MeV case is almost negligible in the view of transverse space charge effect. Therefore, the electron beam is stable up to 10 A order in PNC linac design. Of course, the problem for RF supply is out of consideration here. It is important to estimate other longitudinal effect such as beam bunch effect which is lasting unevaluated. (author)

  8. Quantum electrodynamical effects in heavy highly-charged ions

    International Nuclear Information System (INIS)

    Yerokhin, V.A.; Artemyev, A.N.; Indelicato, P.; Shabaev, V.M.

    2003-01-01

    The present status of theoretical calculations of QED effects in highly charged ions is reviewed for several important cases: the Lamb shift in heavy H-like ions, the 2p 1/2 -2s transition energy in heavy Li-like ions, and the bound-electron g factor in H-like ions. Theoretical predictions are compared with experimental results. Special attention is paid to the discussion of uncertainties of theoretical predictions

  9. The space charge effects on the slow extraction process

    International Nuclear Information System (INIS)

    Ohmori, Chihiro.

    1992-06-01

    The calculation of the slow extraction which includes the space charge effects has been performed for the Compressor/Stretcher Ring (CSR) of the proposed Japanese Hadron Project. We have investigated the slow extraction of 1 GeV proton beam with an average current of 100μA. Calculation shows not only the emittance growth of the extracted beam but also decrease of the extraction efficiency and discontinuity of beam spill. (author)

  10. "Inverted" Solvent Effect on Charge Transfer in the Excited State.

    Science.gov (United States)

    Nau; Pischel

    1999-10-04

    Faster in cyclohexane than in acetonitrile is the fluorescence quenching of the azoalkane 2,3-diazabicyclo[2.2.2]oct-2-ene (DBO) by amines and sulfides. Although this photoreaction is induced by charge transfer (CT; see picture) and exciplexes are formed, the increase in the dipole moment of the exciplex is not large enough to offset the solvent stabilization of the excited reactants, and an "inverted" solvent effect results.

  11. A self-consistent two-dimensional resistive fluid theory of field-aligned potential structures including charge separation and magnetic and velocity shear

    International Nuclear Information System (INIS)

    Hesse, M.; Birn, J.; Schindler, K.

    1990-01-01

    A self-consistent two-fluid theory that includes the magnetic field and shear patterns therein is developed to model stationary electrostatic structures with field-aligned potential drops. Shear flow is also included in the theory since this seems to be a prominent feature of the structures of interest. In addition, Ohmic dissipation, a Hall term and pressure gradients in a generalized Ohm's law, modified for cases without quasi-neutrality are included. In the analytic theory, the electrostatic force is balanced by field-aligned pressure gradients, i.e., thermal effects in the direction of the magnetic field, and by pressure gradients and magnetic stresses in the perpendicular direction. Within this theory simple examples of applications are presented to demonstrate the kind of solutions resulting from the model. The results show how the effects of charge separation and shear in the magnetic field and the velocity can be combined to form self-consistent structures such as are found to exist above the aurora, suggested also in association with solar flares

  12. Separation of 3′-sialyllactose and lactose by nanofiltration: A trade-off between charge repulsion and pore swelling induced by high pH

    DEFF Research Database (Denmark)

    Nordvang, Rune Thorbjørn; Luo, Jianquan; Zeuner, Birgitte

    2014-01-01

    Separation of 3′-sialyllactose (SL) and lactose is an essential final step for the production of the next generation of infant formulas containing sialyllated prebiotics. Due to the difference in molecular weight (MW) between SL and lactose and the charge density of SL, nanofiltration could provide...... a rapid, inexpensive alternative for the separation of SL and lactose compared to traditional chromatography. The performance of four commercial nanofiltration membranes (NF45, DSS-ETNA01PP, NTR-7540 and NP010) for the separation of SL and lactose was assessed at various pH. The difference in retention...... between SL and lactose was only significant in the NP010 and NTR-7450 membranes, whereas the NF45 and DSS ETNA01PP membranes exhibited either too high lactose retention (i.e. insufficient separation) or too low SL retention (i.e. losing the target SL compound), respectively. Operation at increased pH did...

  13. Think positive : phase separation enables a positively charged additive to induce dramatic changes in calcium carbonate morphology

    NARCIS (Netherlands)

    Cantaert, B.; Kim, Y.; Ludwig, H.; Nudelman, F.; Sommerdijk, N.A.J.M.; Meldrum, F.C.

    2012-01-01

    Soluble macromolecules are essential to Nature's control over biomineral formation. Following early studies where macromolecules rich in aspartic and glutamic acid were extracted from nacre, research has focused on the use of negatively charged additives to control calcium carbonate precipitation.

  14. Program NAJOCSC and space charge effect simulation in C01

    International Nuclear Information System (INIS)

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

    1999-01-01

    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.)

  15. The effect of polymer charge density and charge distribution on the formation of multilayers

    CERN Document Server

    Voigt, U; Tauer, K; Hahn, M; Jäger, W; Klitzing, K V

    2003-01-01

    Polyelectrolyte multilayers which are built up by alternating adsorption of polyanions and polycations from aqueous solutions at a solid interface are investigated by reflectometry and ellipsometry. Below a degree of charge of about 70% the adsorption stops after a certain number of dipping cycles and no multilayer formation occurs. This indicates an electrostatically driven adsorption process. Below a charge density of 70% an adsorption can take place if the charged segments are combined as a block of the polymer.

  16. Dynamical mechanism of charge separation by photoexcited generation of proton–electron pairs in organic molecular systems. A nonadiabatic electron wavepacket dynamics study

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Kentaro, E-mail: kyamamoto@fukui.kyoto-u.ac.jp; Takatsuka, Kazuo, E-mail: kaztak@fukui.kyoto-u.ac.jp

    2016-08-22

    Graphical abstract: Asymptotic biradical state produced by the excited-state coupled proton–electron transfer (CPET), resulting in charge separation (proton–electron pair creation) on a proton–electron acceptor A, in a series of photochemical systems generally denoted as X–Mn–OH{sub 2}⋯A, where X = (OH, Ca(OH){sub 3}) and A = (N-methylformamidine, guanidine, imidazole, or ammonia clusters). - Abstract: In this perspective article, we review, along with presenting new results, a series of our theoretical analyses on the excited-state mechanism of charge separation (proton–electron pair creation) relevant to the photoinduced water-splitting reaction (2H{sub 2}O → 4H{sup +} + 4e{sup −} + O{sub 2}) in organic and biological systems, which quite often includes Mn clusters in various molecular configurations. The present mechanism is conceived to be universal in the triggering process of the photoexcited water splitting dynamics. In other words, any Mn-based catalytic charge separation is quite likely to be initiated according to this mechanism. As computationally tractable yet realistic models, we examine a series of systems generally expressed as X–Mn–OH{sub 2}⋯A, where X = (OH, Ca(OH){sub 3}) and A = (N-methylformamidine, guanidine, imidazole or ammonia cluster) in terms of the theory of nonadiabatic electron wavepacket dynamics. We first find both an electron and a proton are simultaneously transferred to the acceptors through conical intersections upon photoexcitation. In this mechanism, the electron takes different pathways from that of the proton and reaches the densely lying Rydberg-like states of the acceptors in the end, thereby inducing charge separation. Therefore the presence of the Rydberg-like diffused unoccupied states as an electron acceptor is critical for this reaction to proceed. We also have found another crucial nonadiabatic process that deteriorates the efficiency of charge separation by rendering the created pair of proton

  17. Charge carrier coherence and Hall effect in organic semiconductors

    Science.gov (United States)

    Yi, H. T.; Gartstein, Y. N.; Podzorov, V.

    2016-01-01

    Hall effect measurements are important for elucidating the fundamental charge transport mechanisms and intrinsic mobility in organic semiconductors. However, Hall effect studies frequently reveal an unconventional behavior that cannot be readily explained with the simple band-semiconductor Hall effect model. Here, we develop an analytical model of Hall effect in organic field-effect transistors in a regime of coexisting band and hopping carriers. The model, which is supported by the experiments, is based on a partial Hall voltage compensation effect, occurring because hopping carriers respond to the transverse Hall electric field and drift in the direction opposite to the Lorentz force acting on band carriers. We show that this can lead in particular to an underdeveloped Hall effect observed in organic semiconductors with substantial off-diagonal thermal disorder. Our model captures the main features of Hall effect in a variety of organic semiconductors and provides an analytical description of Hall mobility, carrier density and carrier coherence factor. PMID:27025354

  18. Charge carrier coherence and Hall effect in organic semiconductors.

    Science.gov (United States)

    Yi, H T; Gartstein, Y N; Podzorov, V

    2016-03-30

    Hall effect measurements are important for elucidating the fundamental charge transport mechanisms and intrinsic mobility in organic semiconductors. However, Hall effect studies frequently reveal an unconventional behavior that cannot be readily explained with the simple band-semiconductor Hall effect model. Here, we develop an analytical model of Hall effect in organic field-effect transistors in a regime of coexisting band and hopping carriers. The model, which is supported by the experiments, is based on a partial Hall voltage compensation effect, occurring because hopping carriers respond to the transverse Hall electric field and drift in the direction opposite to the Lorentz force acting on band carriers. We show that this can lead in particular to an underdeveloped Hall effect observed in organic semiconductors with substantial off-diagonal thermal disorder. Our model captures the main features of Hall effect in a variety of organic semiconductors and provides an analytical description of Hall mobility, carrier density and carrier coherence factor.

  19. Charge-scaling effect in ionic liquids from the charge-density analysis of N,N'-dimethylimidazolium methylsulfate.

    Science.gov (United States)

    Beichel, Witali; Trapp, Nils; Hauf, Christoph; Kohler, Oliver; Eickerling, Georg; Scherer, Wolfgang; Krossing, Ingo

    2014-03-17

    The charge scaling effect in ionic liquids was explored on the basis of experimental and theoretical chargedensity analyses of [C1MIM][C1SO4] employing the quantum theory of atoms in molecules (QTAIM) approach. Integrated QTAIM charges of the experimental (calculated) charge density of the cation and anion resulted in non-integer values of ±0.90 (±0.87) e. Efficient charge transfer along the bond paths of the hydrogen bonds between the imidazolium ring and the anion was considered as the origin of these reduced charges. In addition, a detailed QTAIM analysis of the bonding situation in the [C1SO4]- anion revealed the presence of negative πO→σ*S-O hyperconjugation.

  20. Effect of three-body forces on the phase behavior of charged colloids

    International Nuclear Information System (INIS)

    Wu, J. Z.; Bratko, D.; Blanch, H. W.; Prausnitz, J. M.

    2000-01-01

    Statistical-thermodynamic theory for predicting the phase behavior of a colloidal solution requires the pair interaction potential between colloidal particles in solution. In practice, it is necessary to assume pairwise additivity for the potential of mean force between colloidal particles, but little is known concerning the validity of this assumption. This paper concerns interaction between small charged colloids, such as surfactant micelles or globular proteins, in electrolyte solutions and the multibody effect on phase behavior. Monte Carlo simulations for isolated colloidal triplets in equilateral configurations show that, while the three-body force is repulsive when the three particles are near contact, it becomes short-ranged attractive at further separations, contrary to a previous study where the triplet force is attractive at all separations. The three-body force arises mainly from hard-sphere collisions between colloids and small ions; it is most significant in solutions of monovalent salt at low concentration where charged colloids experience strong electrostatic interactions. To illustrate the effect of three-body forces on the phase behavior of charged colloids, we calculated the densities of coexisting phases using van der Waals-type theories for colloidal solutions and for crystals. For the conditions investigated in this work, even though the magnitude of the three-body force may be as large as 10% of the total force at small separations, three-body forces do not have a major effect on the densities of binary coexisting phases. However, coexisting densities calculated using Derjaguin-Landau-Verwey-Overbeek theory are much different from those calculated using our simulated potential of mean force. (c) 2000 American Institute of Physics

  1. Interfacial charge separation and recombination in InP and quasi-type II InP/CdS core/shell quantum dot-molecular acceptor complexes.

    Science.gov (United States)

    Wu, Kaifeng; Song, Nianhui; Liu, Zheng; Zhu, Haiming; Rodríguez-Córdoba, William; Lian, Tianquan

    2013-08-15

    Recent studies of group II-VI colloidal semiconductor heterostuctures, such as CdSe/CdS core/shell quantum dots (QDs) or dot-in-rod nanorods, show that type II and quasi-type II band alignment can facilitate electron transfer and slow down charge recombination in QD-molecular electron acceptor complexes. To explore the general applicability of this wave function engineering approach for controlling charge transfer properties, we investigate exciton relaxation and dissociation dynamics in InP (a group III-V semiconductor) and InP/CdS core/shell (a heterostructure beween group III-V and II-VI semiconductors) QDs by transient absorption spectroscopy. We show that InP/CdS QDs exhibit a quasi-type II band alignment with the 1S electron delocalized throughout the core and shell and the 1S hole confined in the InP core. In InP-methylviologen (MV(2+)) complexes, excitons in the QD can be dissociated by ultrafast electron transfer to MV(2+) from the 1S electron level (with an average time constant of 11.4 ps) as well as 1P and higher electron levels (with a time constant of 0.39 ps), which is followed by charge recombination to regenerate the complex in its ground state (with an average time constant of 47.1 ns). In comparison, InP/CdS-MV(2+) complexes show similar ultrafast charge separation and 5-fold slower charge recombination rates, consistent with the quasi-type II band alignment in these heterostructures. This result demonstrates that wave function engineering in nanoheterostructures of group III-V and II-VI semiconductors provides a promising approach for optimizing their light harvesting and charge separation for solar energy conversion applications.

  2. How to aggregate health? Separability and the effect of framing.

    Science.gov (United States)

    Turpcu, Adam; Bleichrodt, Han; Le, Quang A; Doctor, Jason N

    2012-01-01

    Unweighted summation or quality-adjusted life year (QALY) utilitarianism is the most common way to aggregate health benefits in a cost-effectiveness analysis. A key qualitative principle underlying QALY utilitarianism is separability: those individuals unaffected by a policy choice should not influence the policy choice. Separability also underlies several of the alternatives for QALY utilitarianism that have been proposed. To test separability and to test whether the support for separability is affected by the framing of the choice questions. In 2 experiments, 345 student subjects (162 in the first experiment, and 183 in the second experiment) were asked to select 1 of 2 possible treatments, with each treatment resulting in a different distribution of health across individuals. The only aspect that varied across choice questions was the state of the patients whose health was unaffected by the act of choosing a policy. In each experiment, we used 2 frames. In the implicit frame, it was implied but not plainly expressed what outcomes the treatments had in common. In the explicit frame, common outcomes of the 2 treatments were directly stated. The 2 experiments differed in the way the explicit frame was presented (verbal v. numerical). The support for separability was significantly greater in the explicit frame. The proportion of violations in the implicit frame was 44% in Experiment 1 and 31% in Experiment 2, while in the explicit frame, the proportion of violations was 28% in Experiment 1 and 8% in Experiment 2. Framing affected the support for separability, raising issues as to whether it is possible to achieve a canonical representation of social choices.

  3. Ultrafast Exciton Dissociation and Long-Lived Charge Separation in a Photovoltaic Pentacene-MoS2 van der Waals Heterojunction.

    Science.gov (United States)

    Bettis Homan, Stephanie; Sangwan, Vinod K; Balla, Itamar; Bergeron, Hadallia; Weiss, Emily A; Hersam, Mark C

    2017-01-11

    van der Waals heterojunctions between two-dimensional (2D) layered materials and nanomaterials of different dimensions present unique opportunities for gate-tunable optoelectronic devices. Mixed-dimensional p-n heterojunction diodes, such as p-type pentacene (0D) and n-type monolayer MoS 2 (2D), are especially interesting for photovoltaic applications where the absorption cross-section and charge transfer processes can be tailored by rational selection from the vast library of organic molecules and 2D materials. Here, we study the kinetics of excited carriers in pentacene-MoS 2 p-n type-II heterojunctions by transient absorption spectroscopy. These measurements show that the dissociation of MoS 2 excitons occurs by hole transfer to pentacene on the time scale of 6.7 ps. In addition, the charge-separated state lives for 5.1 ns, up to an order of magnitude longer than the recombination lifetimes from previously reported 2D material heterojunctions. By studying the fractional amplitudes of the MoS 2 decay processes, the hole transfer yield from MoS 2 to pentacene is found to be ∼50%, with the remaining holes undergoing trapping due to surface defects. Overall, the ultrafast charge transfer and long-lived charge-separated state in pentacene-MoS 2 p-n heterojunctions suggest significant promise for mixed-dimensional van der Waals heterostructures in photovoltaics, photodetectors, and related optoelectronic technologies.

  4. Combined effects of headgroup charge and tail unsaturation of lipids on lateral organization and diffusion of lipids in model biomembranes

    International Nuclear Information System (INIS)

    Chen Xiao-Jie; Liang Qing

    2017-01-01

    Lateral organization and dynamics of lipids in plasma membranes are crucial for several cellular processes such as signal transduction across the membrane and still remain elusive. In this paper, using coarse-grained molecular dynamics simulation, we theoretically study the combined effects of headgroup charge and tail unsaturation of lipids on the lateral organization and diffusion of lipids in ternary lipid bilayers. In neutral ternary lipid bilayers composed of saturated lipids, unsaturated lipids, and cholesterols, under the conditions of given temperature and components, the main factor for the phase separation is the unsaturation of unsaturated lipids and the bilayers can be separated into liquid-ordered domains enriched in saturated lipids and cholesterols and liquid-disordered domains enriched in unsaturated lipids. Once the headgroup charge is introduced, the electrostatic repulsion between the negatively charged lipid headgroups will increase the distance between the charged lipids. We find that the lateral organization and diffusion of the lipids in the (partially) charged ternary lipid bilayers are determined by the competition between the headgroup charge and the unsaturation of the unsaturated lipids. In the bilayers containing unsaturated lipids with lower unsaturation, the headgroup charge plays a crucial role in the lateral organization and diffusion of lipids. The headgroup charge may make the lipid domains unstable and even can suppress phase separation of the lipids in some systems. However, in the bilayers containing highly unsaturated lipids, the lateral organization and diffusion of lipids are mainly dominated by the unsaturation of the unsaturated lipids. This work may provide some theoretical insights into understanding the formation of nanosized domains and lateral diffusion of lipids in plasma membranes. (paper)

  5. 3D Simulations of Space Charge Effects in Particle Beams

    Energy Technology Data Exchange (ETDEWEB)

    Adelmann, A

    2002-10-01

    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)

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

    International Nuclear Information System (INIS)

    Adelmann, A.

    2002-10-01

    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 (∼ 10 9 protons/cm 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. Simulation of space charge effects in a synchrotron

    International Nuclear Information System (INIS)

    Machida, Shinji; Ikegami, Masanori

    1998-01-01

    We have studied space charge effects in a synchrotron with multi-particle tracking in 2-D and 3-D configuration space (4-D and 6-D phase space, respectively). First, we will describe the modelling of space charge fields in the simulation and a procedure of tracking. Several ways of presenting tracking results will be also mentioned. Secondly, it is discussed as a demonstration of the simulation study that coherent modes of a beam play a major role in beam stability and intensity limit. The incoherent tune in a resonance condition should be replaced by the coherent tune. Finally, we consider the coherent motion of a beam core as a driving force of halo formation. The mechanism is familiar in linac, and we apply it in a synchrotron

  8. Charge Separation in Intermixed Polymer:PC70BM Photovoltaic Blends: Correlating Structural and Photophysical Length Scales as a Function of Blend Composition

    KAUST Repository

    Utzat, Hendrik

    2017-04-24

    A key challenge in achieving control over photocurrent generation by bulk-heterojunction organic solar cells is understanding how the morphology of the active layer impacts charge separation and in particular the separation dynamics within molecularly intermixed donor-acceptor domains versus the dynamics between phase-segregated domains. This paper addresses this issue by studying blends and devices of the amorphous silicon-indacenodithiophene polymer SiIDT-DTBT and the acceptor PCBM. By changing the blend composition, we modulate the size and density of the pure and intermixed domains on the nanometer length scale. Laser spectroscopic studies show that these changes in morphology correlate quantitatively with the changes in charge separation dynamics on the nanosecond time scale and with device photocurrent densities. At low fullerene compositions, where only a single, molecularly intermixed polymer-fullerene phase is observed, photoexcitation results in a ∼ 30% charge loss from geminate polaron pair recombination, which is further studied via light intensity experiments showing that the radius of the polaron pairs in the intermixed phase is 3-5 nm. At high fullerene compositions (≥67%), where the intermixed domains are 1-3 nm and the pure fullerene phases reach ∼4 nm, the geminate recombination is suppressed by the reduction of the intermixed phase, making the fullerene domains accessible for electron escape.

  9. Effect of pion external distortion on low energy pion double-charge-exchange

    International Nuclear Information System (INIS)

    Khankhasaev, M.Kh.; Kurmanov, Zh.B.; Johnson, M.B.

    1993-01-01

    The effects of the external pion distortion for iso-elastic charge exchange scattering (within the framework of the isospin invariant optical model) is considered. An approximated method of taking into account the distortion based on the separable expansion of the optical potential in momentum space is developed. The result of external distortions for sequential scattering 14 C(π + , π - ) 14 O at 50 MeV is presented. It is shown that this distortion gives a small enhancement to forward and reduced the differential cross sections at large angels. 22 refs., 5 figs., 1 tab

  10. Source Separation of Heartbeat Sounds for Effective E-Auscultation

    Science.gov (United States)

    Geethu, R. S.; Krishnakumar, M.; Pramod, K. V.; George, Sudhish N.

    2016-03-01

    This paper proposes a cost effective solution for improving the effectiveness of e-auscultation. Auscultation is the most difficult skill for a doctor, since it can be acquired only through experience. The heart sound mixtures are captured by placing the four numbers of sensors at appropriate auscultation area in the body. These sound mixtures are separated to its relevant components by a statistical method independent component analysis. The separated heartbeat sounds can be further processed or can be stored for future reference. This idea can be used for making a low cost, easy to use portable instrument which will be beneficial to people living in remote areas and are unable to take the advantage of advanced diagnosis methods.

  11. Space charge effect in SQS transition in a gas counter

    International Nuclear Information System (INIS)

    Ohgaki, Hideaki; Kametani, Hitoshi; Fujita, Yasuyuki; Uozumi, Yuusuke; Ijiri, Hidenobu; Matoba, Masaru; Sakae, Takeji; Koori, Norihiko

    1990-01-01

    Systematic investigation of the gas multiplication characteristics in the transition region from proportional to SQS mode in a cylindrical proportional counter has been performed. The property of saturation of the gas multiplication factor can be reproduced using the effective electric field which is corrected for the space charge related to the positive ion density in the avalanche. Photon-mediated gas multiplication can explain the large jump phenomenon of the SQS transition. It is shown that the effective electric field in the avalanche becomes almost zero near the anode surface (Meek's streamer condition) at the 50% transition voltage and the region of its maximum moves slightly away from the anode surface. (orig.)

  12. Cataractogenic effects of heavy charged particles in mice

    International Nuclear Information System (INIS)

    Ainsworth, E.J.; Jose, J.G.; Yang, V.V.; Barker, M.E.

    1980-01-01

    The effects of heavy charged particles on the crystalline lens of the eye of mice are important because this tissue has proven susceptible to other forms of high-LET radiation. This report summarizes the results currently available from a prospectively designed study to explore the LET dependence of the cataractogenic process. The present results are consistent with a high cataractogenic effect at 100 keV/μm, because plateau argon 40 ions, with an LET in this range, produce higher average cataracts scores at 9, 11 and 13 months than do carbon 12 or neon 20 ions. In the electron micrographs, significant changes were observed from the controls

  13. Aerodynamic effects in isotope separation by gaseous diffusion

    International Nuclear Information System (INIS)

    Bert, L.A.; Prosperetti, A.; Fiocchi, R.

    1978-01-01

    The turbulent flow of an isotopic mixture in a porous-walled pipe is considered in the presence of suction through the wall. A simple model is formulated for the evaluation of aerodynamic effects on the separation efficiency. The predictions of the model are found to compare very favourably with experiment. In the limit of small suction velocities, results obtained by other investigators for diffusion in a turbulent steam are recovered. (author)

  14. Study of the average charge states of 188Pb and 252,254No ions at the gas-filled separator TASCA

    International Nuclear Information System (INIS)

    Khuyagbaatar, J.; Ackermann, D.; Andersson, L.-L.; Ballof, J.; Brüchle, W.; Düllmann, Ch.E.; Dvorak, J.; Eberhardt, K.; Even, J.; Gorshkov, A.; Graeger, R.; Heßberger, F.-P.; Hild, D.; Hoischen, R.; Jäger, E.; Kindler, B.

    2012-01-01

    The average charge states of 188 Pb and 252,254 No ions in dilute helium gas were measured at the gas-filled recoil separator TASCA. Hydrogen gas was also used as a filling gas for measurements of the average charge state of 254 No. Helium and hydrogen gases at pressures from 0.2 mbar to 2.0 mbar were used. A strong dependence of the average charge state on the pressure of the filling gases was observed for both, helium and hydrogen. The influence of this dependence, classically attributed to the so-called “density effect”, on the performance of TASCA was investigated. The average charge states of 254 No ions were also measured in mixtures of helium and hydrogen gases at low gas pressures around 1.0 mbar. From the experimental results simple expressions for the prediction of average charge states of heavy ions moving in rarefied helium gas, hydrogen gas, and in their mixture were derived.

  15. From Recombination Dynamics to Device Performance: Quantifying the Efficiency of Exciton Dissociation, Charge Separation, and Extraction in Bulk Heterojunction Solar Cells with Fluorine-Substituted Polymer Donors

    KAUST Repository

    Gorenflot, Julien

    2017-09-28

    An original set of experimental and modeling tools is used to quantify the yield of each of the physical processes leading to photocurrent generation in organic bulk heterojunction solar cells, enabling evaluation of materials and processing condition beyond the trivial comparison of device performances. Transient absorption spectroscopy, “the” technique to monitor all intermediate states over the entire relevant timescale, is combined with time-delayed collection field experiments, transfer matrix simulations, spectral deconvolution, and parametrization of the charge carrier recombination by a two-pool model, allowing quantification of densities of excitons and charges and extrapolation of their kinetics to device-relevant conditions. Photon absorption, charge transfer, charge separation, and charge extraction are all quantified for two recently developed wide-bandgap donor polymers: poly(4,8-bis((2-ethylhexyl)oxy)benzo[1,2-b:4,5-b′]dithiophene-3,4-difluorothiophene) (PBDT[2F]T) and its nonfluorinated counterpart poly(4,8-bis((2-ethylhexyl)oxy)benzo[1,2-b:4,5-b′]dithiophene-3,4-thiophene) (PBDT[2H]T) combined with PC71BM in bulk heterojunctions. The product of these yields is shown to agree well with the devices\\' external quantum efficiency. This methodology elucidates in the specific case studied here the origin of improved photocurrents obtained when using PBDT[2F]T instead of PBDT[2H]T as well as upon using solvent additives. Furthermore, a higher charge transfer (CT)-state energy is shown to lead to significantly lower energy losses (resulting in higher VOC) during charge generation compared to P3HT:PCBM.

  16. From Recombination Dynamics to Device Performance: Quantifying the Efficiency of Exciton Dissociation, Charge Separation, and Extraction in Bulk Heterojunction Solar Cells with Fluorine-Substituted Polymer Donors

    KAUST Repository

    Gorenflot, Julien; Paulke, Andreas; Piersimoni, Fortunato; Wolf, Jannic Sebastian; Kan, Zhipeng; Cruciani, Federico; El Labban, Abdulrahman; Neher, Dieter; Beaujuge, Pierre; Laquai, Fré dé ric

    2017-01-01

    An original set of experimental and modeling tools is used to quantify the yield of each of the physical processes leading to photocurrent generation in organic bulk heterojunction solar cells, enabling evaluation of materials and processing condition beyond the trivial comparison of device performances. Transient absorption spectroscopy, “the” technique to monitor all intermediate states over the entire relevant timescale, is combined with time-delayed collection field experiments, transfer matrix simulations, spectral deconvolution, and parametrization of the charge carrier recombination by a two-pool model, allowing quantification of densities of excitons and charges and extrapolation of their kinetics to device-relevant conditions. Photon absorption, charge transfer, charge separation, and charge extraction are all quantified for two recently developed wide-bandgap donor polymers: poly(4,8-bis((2-ethylhexyl)oxy)benzo[1,2-b:4,5-b′]dithiophene-3,4-difluorothiophene) (PBDT[2F]T) and its nonfluorinated counterpart poly(4,8-bis((2-ethylhexyl)oxy)benzo[1,2-b:4,5-b′]dithiophene-3,4-thiophene) (PBDT[2H]T) combined with PC71BM in bulk heterojunctions. The product of these yields is shown to agree well with the devices' external quantum efficiency. This methodology elucidates in the specific case studied here the origin of improved photocurrents obtained when using PBDT[2F]T instead of PBDT[2H]T as well as upon using solvent additives. Furthermore, a higher charge transfer (CT)-state energy is shown to lead to significantly lower energy losses (resulting in higher VOC) during charge generation compared to P3HT:PCBM.

  17. EFFECT OF GLYCEROL SEPARATION ON PALM OIL TRANSESTERIFICATION

    Directory of Open Access Journals (Sweden)

    Budy Rahmat

    2012-12-01

    Full Text Available This research was aimed to study the effect of glycerol separation on palm oil transesterification. Objectives of this study were to suppress the use of excess methanol and shorten the processing time. This research consisted of: design-build reactor, the effect of the glycerol separation on the transesterification reaction, characterization of biodiesel, and mass balance analysis. The reactor was designed by integrating circulate stirrer pump, static mixer, and sprayer that will bring out the intense reaction in the outer tank reactor. The experiment in this research was the treatment of decreasing the quantity of methanol to 5:1 molar ratio and reducing of processing time to 20 min, which was arranged in a completely randomized factorial design. The result showed that, (i the stirring system was effectively worked outside the reactor tank, and in its reactor tank occurred glycerol separation during the process; (ii the rate of glycerol during the process followed the inverse regression equation of Ŷ = 66.44-351.17 X-1; (iii the decrease in the level of methanol to 5:1 molar ratio and the reduction of processing time to 20 min in this engineering did not influence the biodiesel yield and quality that met the SNI 04-7182-2006 standard.

  18. 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

    2009-12-01

    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.

  19. Separating Gender Composition Effects from Peer Effects in Education

    Science.gov (United States)

    Jahanshahi, Babak

    2017-01-01

    This paper aims to demonstrate the importance of controlling for endogenous peer effects in estimating the influence of gender peer effects on educational outcomes. Using Manski's linear-in-means model, this paper illustrates that the estimation of gender peer effects is potentially biased in the presence of endogenous peer effect in education.…

  20. Effect of atomic disorder on the magnetic phase separation

    Science.gov (United States)

    Groshev, A. G.; Arzhnikov, A. K.

    2018-05-01

    The effect of disorder on the magnetic phase separation between the antiferromagnetic and incommensurate helical and phases is investigated. The study is based on the quasi-two-dimensional single-band Hubbard model in the presence of atomic disorder (the Anderson–Hubbard model). A model of binary alloy disorder is considered, in which the disorder is determined by the difference in energy between the host and impurity atomic levels at a fixed impurity concentration. The problem is solved within the theory of functional integration in static approximation. Magnetic phase diagrams are obtained as functions of the temperature, the number of electrons and impurity concentration with allowance for phase separation. It is shown that for the model parameters chosen, the disorder caused by impurities whose atomic-level energy is greater than that of the host atomic levels, leads to qualitative changes in the phase diagram of the impurity-free system. In the opposite case, only quantitative changes occur. The peculiarities of the effect of disorder on the phase separation regions of the quasi-two-dimensional Hubbard model are discussed.

  1. Irradiation of graphene field effect transistors with highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-09-01

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

  2. Effect of nonequilibrium degree on separation factor in carbon isotope separation by CO2 microwave discharge

    International Nuclear Information System (INIS)

    Masaaki Suzuki; Shinsuke Mori; Noritaka Matsumoto; Hiroshi Akatsuka

    1999-01-01

    The local separation factor and the local nonequilibrium degree just behind the plasma region were obtained. The plasma gas compositions measured by the enthalpy probe system were substantially thermodynamic nonequilibrium conditions, when the input energy was 4 J/cm 3 . The measured maximum value of the separation factor was 1.01, although it changed locally. The measured separation factor and its nonequilibrium condition were discussed. Anyway, the only small value obtained in this experiments is similar to the recent data obtained by Kurchatov group and is less than published data, which is measured spectroscopically [ru

  3. Capillary Isoelectric Focusing-Mass Spectrometry Method for the Separation and Online Characterization of Intact Monoclonal Antibody Charge Variants.

    Science.gov (United States)

    Dai, Jun; Lamp, Jared; Xia, Qiangwei; Zhang, Yingru

    2018-02-06

    We report a new online capillary isoelectric focusing-mass spectrometry (CIEF-MS) method for monoclonal antibody (mAb) charge variant analysis using an electrokinetically pumped sheath-flow nanospray ion source and a time-of-flight MS with pressure-assisted chemical mobilization. To develop a successful, reliable CIEF-MS method for mAb, we have selected and optimized many critical, interrelating reagents and parameters that include (1) MS-friendly anolyte and catholyte; (2) a glycerol enhanced sample mixture that reduced non-CIEF electrophoretic mobility and band broadening; (3) ampholyte selected for balancing resolution and MS sensitivity; (4) sheath liquid composition optimized for efficient focusing, mobilization, and electrospray ionization; (5) judiciously selected CIEF running parameters including injection amount, field strength, and applied pressure. The fundamental premise of CIEF was well maintained as verified by the linear correlation (R 2 = 0.99) between pI values and migration time using a mixture of pI markers. In addition, the charge variant profiles of trastuzumab, bevacizumab, infliximab, and cetuximab, obtained using this CIEF-MS method, were corroborated by imaged CIEF-UV (iCIEF-UV) analyses. The relative standard deviations (RSD) of absolute migration time of pI markers were all less than 5% (n = 4). Triplicate analyses of bevacizumab showed RSD less than 1% for relative migration time to an internal standard and RSD of 7% for absolute MS peak area. Moreover, the antibody charge variants were characterized using the online intact MS data. To the best of our knowledge, this is the first time that direct online MS detection and characterization were achieved for mAb charge variants resolved by CIEF as indicated by a well-established linear pH gradient and correlated CIEF-UV charge variant profiles.

  4. Space-charge effects in high-energy photoemission

    Energy Technology Data Exchange (ETDEWEB)

    Verna, Adriano, E-mail: adriano.verna@uniroma3.it [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)

    2016-05-15

    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

  5. Space charge effects for multipactor in coaxial lines

    Energy Technology Data Exchange (ETDEWEB)

    Sorolla, E., E-mail: eden.sorolla@xlim.fr [XLIM, UMR 7252, Université de Limoges/CNRS, 123 Av. Albert Thomas, 87060 Limoges (France); Sounas, A.; Mattes, M. [Laboratoire d' Électromagnétisme et d' Acoustique (LEMA), École Polytechnique Fédérale de Lausanne, Station 11, CH-1015 Lausanne (Switzerland)

    2015-03-15

    Multipactor is a hazardous vacuum discharge produced by secondary electron emission within microwave devices of particle accelerators and telecommunication satellites. This work analyzes the dynamics of the multipactor discharge within a coaxial line for the mono-energetic electron emission model taking into account the space charge effects. The steady-state is predicted by the proposed model and an analytical expression for the maximum number of electrons released by the discharge presented. This could help to link simulations to experiments and define a multipactor onset criterion.

  6. Space charge effects for multipactor in coaxial lines

    International Nuclear Information System (INIS)

    Sorolla, E.; Sounas, A.; Mattes, M.

    2015-01-01

    Multipactor is a hazardous vacuum discharge produced by secondary electron emission within microwave devices of particle accelerators and telecommunication satellites. This work analyzes the dynamics of the multipactor discharge within a coaxial line for the mono-energetic electron emission model taking into account the space charge effects. The steady-state is predicted by the proposed model and an analytical expression for the maximum number of electrons released by the discharge presented. This could help to link simulations to experiments and define a multipactor onset criterion

  7. The effect of errors in charged particle beams

    International Nuclear Information System (INIS)

    Carey, D.C.

    1987-01-01

    Residual errors in a charged particle optical system determine how well the performance of the system conforms to the theory on which it is based. Mathematically possible optical modes can sometimes be eliminated as requiring precisions not attainable. Other plans may require introduction of means of correction for the occurrence of various errors. Error types include misalignments, magnet fabrication precision limitations, and magnet current regulation errors. A thorough analysis of a beam optical system requires computer simulation of all these effects. A unified scheme for the simulation of errors and their correction is discussed

  8. Basal electric and magnetic fields of celestial bodies come from positive-negative charge separation caused by gravitation of quasi-Casimir pressure in weak interaction

    Science.gov (United States)

    Chen, Shao-Guang

    According to f =d(mv)/dt=m(dv/dt)+ v(dm/dt), a same gravitational formula had been de-duced from the variance in physical mass of QFT and from the variance in mass of inductive energy-transfer of GR respectively: f QF T = f GR = -G (mM/r2 )((r/r)+(v/c)) when their interaction-constants are all taken the experimental values (H05-0029-08, E15-0039-08). f QF T is the quasi-Casimir pressure. f GR is equivalent to Einstein's equation, then more easy to solve it. The hypothesis of the equivalent principle is not used in f QF T , but required by f GR . The predictions of f QF T and f GR are identical except that f QF T has quantum effects but f GR has not and f GR has Lense-Thirring effect but f QF T has not. The quantum effects of gravitation had been verified by Nesvizhevsky et al with the ultracold neutrons falling in the earth's gravitational field in 2002. Yet Lense-Thirring effect had not been measured by GP-B. It shows that f QF T is essential but f GR is phenomenological. The macro-f QF T is the statistic average pressure collided by net virtual neutrinos ν 0 flux (after self-offset in opposite directions) and in direct proportion to the mass. But micro-f QF T is in direct proportion to the scattering section. The electric mass (in inverse proportion to de Broglie wavelength λ) far less than nucleonic mass and the electric scattering section (in direct proportion to λ2 ) far large than that of nucleon, then the net ν 0 flux pressure exerted to electron far large than that to nucleon and the electric displacement far large than that of nucleon, it causes the gravitational polarization of positive-negative charge center separation. Because the gravity far less than the electromagnetic binding force, in atoms the gravitational polarization only produces a little separation. But the net ν 0 flux can press a part freedom electrons in plasma of ionosphere into the earth's surface, the static electric force of redundant positive ions prevents electrons from further

  9. Charge correlation effects on ionization of weak polyelectrolytes

    International Nuclear Information System (INIS)

    Panagiotopoulos, A Z

    2009-01-01

    Ionization curves of weak polyelectrolytes were obtained as a function of the charge coupling strength from Monte Carlo simulations. In contrast to many earlier studies, the present work treats counterions explicitly, thus allowing the investigation of charge correlation effects at strong couplings. For conditions representing typical weak polyelectrolytes in water near room temperature, ionization is suppressed because of interactions between nearby dissociated groups, as also seen in prior work. A novel finding here is that, for stronger couplings, relevant for non-aqueous environments in the absence of added salt, the opposite behavior is observed-ionization is enhanced relative to the behavior of the isolated groups due to ion-counterion correlation effects. The fraction of dissociated groups as a function of position along the chain also behaves non-monotonically. Dissociation is highest near the ends of the chains for aqueous polyelectrolytes and highest at the chain middle segments for non-aqueous environments. At intermediate coupling strengths, dissociable groups appear to behave in a nearly ideal fashion, even though chain dimensions still show strong expansion effects due to ionization. These findings provide physical insights on the impact of competition between acid/base chemical equilibrium and electrostatic attractions in ionizable systems.

  10. Separate effects of background and illumination on lightness

    Directory of Open Access Journals (Sweden)

    Zdravković Sunčica

    2007-01-01

    Full Text Available Four experiments attempted to establish an effect of context on lightness. Lightness is one of the dimensions of color and it varies from black to white. Most of our stimuli were inspired by simultaneous lightness contrast illusion. First two experiments contrast the size of an effect produced by the change of background color vs. the change in illumination. The third experiment deals with different type of illusions, where the effect is obtained through the appearance of multiple illumination levels. The last experiment takes into account the ratio of the target and the background. The results reveal the size of effects produced separately by the background color and illumination level and suggest the prime importance of background. Also there are other factors such as reflectance range in the scene, incremental and decremental targets, and 2D vs. 3D representation.

  11. The effect of charged groups on hydrophilic monolithic stationary phases on their chromatographic properties.

    Science.gov (United States)

    Li, Haibin; Liu, Chusheng; Wang, Qiqin; Zhou, Haibo; Jiang, Zhengjin

    2016-10-21

    In order to investigate the effect of charged groups present in hydrophilic monolithic stationary phases on their chromatographic properties, three charged hydrophilic monomers, i.e. N,N-dimethyl-N-acryloyloxyethyl-N-(3-sulfopropyl)ammonium betaine (SPDA), [2-(acryloyloxy)ethyl]trimethylammonium chloride (AETA), and 3-sulfopropyl acrylate potassium salt (SPA) were co-polymerized with the crosslinker N,N'-methylenebisacrylamide (MBA), respectively. The physicochemical properties of the three resulting charged hydrophilic monolithic columns were evaluated using scanning electron microscopy, ζ-potential analysis and micro-HPLC. High column efficiency was obtained on the three monolithic columns at a linear velocity of 1mm/s using thiourea as test compound. Comparative characterization of the three charged HILIC phases was then carried out using a set of model compounds, including nucleobases, nucleosides, benzoic acid derivatives, phenols, β-blockers and small peptides. Depending on the combination of stationary phase/mobile phase/solute, both hydrophilic interaction and other potential secondary interactions, including electrostatic interaction, hydrogen-bonding interaction, molecular shape selectivity, could contribute to the over-all retention of the analytes. Because of the strong electrostatic interaction provided by the quaternary ammonium groups in the poly (AETA-co-MBA) monolith, this cationic HILIC monolith exhibited the strongest retention for benzoic acid derivatives and small peptides with distorted peak shapes and the weakest retention for basic β-blockers. The sulfonyl groups on the poly (SPA-co-MBA) hydrophilic monolith could provide strong electrostatic attraction and hydrogen bonding for positively charged analytes and hydrogen-donor/acceptor containing analytes, respectively. Therefore, basic drugs, nucleobases and nucleotides exhibited the strongest retention on this anionic monolith. Because of the weak but distinct cation exchange properties of

  12. Design principle for efficient charge separation at the donor-acceptor interface for high performance organic solar cell device

    Science.gov (United States)

    Nie, Wanyi; Gupta, Gautam; Crone, Brian; Wang, Hsing-Lin; Mohite, Aditya; MPA-11 Material synthesis and integrated device Team; MPA-chemistry Team

    2014-03-01

    The performance of donor (D) /acceptor (A) structure based organic electronic devices, such as solar cell, light emitting devices etc., relays on the charge transfer process at the interface dramatically. In organic solar cell, the photo-induced electron-hole pair is tightly bonded and will form a charge transfer (CT) state at the D/A interface after dissociation. There is a large chance for them to recombine through CT state and thus is a major loss that limit the overall performance. Here, we report three different strategies that allow us to completely suppress the exciplex (or charge transfer state) recombination between any D/A system. We observe that the photocurrent increases by 300% and the power conversion efficiency increases by 4-5 times simply by inserting a spacer layer in the form of an a) insulator b) Oliogomer or using a c) heavy atom at the donor-acceptor interface in a P3HT/C60 bilayer device. By using those different functional mono layers, we successfully suppressed the exciplex recombination in evidence of increased photocurrent and open circuit voltage. Moreover, these strategies are applicable universally to any donor-acceptor interface. And we demonstrated such strategies in a bulk-heterojunction device which improved the power conversion efficiency from 3.5% up to 4.6%.

  13. 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: krchu@yahoo.com.tw [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China)

    2015-08-15

    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.

  14. Improving the Photo-Oxidative Performance of Bi2MoO6 by Harnessing the Synergy between Spatial Charge Separation and Rational Co-Catalyst Deposition.

    Science.gov (United States)

    Wu, Xuelian; Hart, Judy N; Wen, Xiaoming; Wang, Liang; Du, Yi; Dou, Shi Xue; Ng, Yun Hau; Amal, Rose; Scott, Jason

    2018-03-21

    It has been reported that photogenerated electrons and holes can be directed toward specific crystal facets of a semiconductor particle, which is believed to arise from the differences in their surface electronic structures, suggesting that different facets can act as either photoreduction or photo-oxidation sites. This study examines the propensity for this effect to occur in faceted, plate-like bismuth molybdate (Bi 2 MoO 6 ), which is a useful photocatalyst for water oxidation. Photoexcited electrons and holes are shown to be spatially separated toward the {100} and {001}/{010} facets of Bi 2 MoO 6 , respectively, by facet-dependent photodeposition of noble metals (Pt, Au, and Ag) and metal oxides (PbO 2 , MnO x , and CoO x ). Theoretical calculations revealed that differences in energy levels between the conduction bands and valence bands of the {100} and {001}/{010} facets can contribute to electrons and holes being drawn to different surfaces of the plate-like Bi 2 MoO 6 . Utilizing this knowledge, the photo-oxidative capability of Bi 2 MoO 6 was improved by adding an efficient water oxidation co-catalyst, CoO x , to the system, whereby the extent of enhancement was shown to be governed by the co-catalyst location. A greater oxygen evolution occurred when CoO x was selectively deposited on the hole-rich {001}/{010} facets of Bi 2 MoO 6 compared to when CoO x was randomly located across all of the facets. The elevated performance exhibited for the selectively loaded CoO x /Bi 2 MoO 6 was ascribed to the greater opportunity for hole trapping by the co-catalyst being accentuated over other potentially detrimental effects, such as the co-catalyst acting as a recombination medium and/or covering reactive sites. The results indicate that harnessing the synergy between the spatial charge separation and the co-catalyst location on the appropriate facets of plate-like Bi 2 MoO 6 can promote its photocatalytic activity.

  15. The effects of electron-hole separation on the photoconductivity of individual metal oxide nanowires

    International Nuclear Information System (INIS)

    Prades, J D; Hernandez-Ramirez, F; Jimenez-Diaz, R; Manzanares, M; Andreu, T; Cirera, A; Romano-Rodriguez, A; Morante, J R

    2008-01-01

    The responses of individual ZnO nanowires to UV light demonstrate that the persistent photoconductivity (PPC) state is directly related to the electron-hole separation near the surface. Our results demonstrate that the electrical transport in these nanomaterials is influenced by the surface in two different ways. On the one hand, the effective mobility and the density of free carriers are determined by recombination mechanisms assisted by the oxidizing molecules in air. This phenomenon can also be blocked by surface passivation. On the other hand, the surface built-in potential separates the photogenerated electron-hole pairs and accumulates holes at the surface. After illumination, the charge separation makes the electron-hole recombination difficult and originates PPC. This effect is quickly reverted after increasing either the probing current (self-heating by Joule dissipation) or the oxygen content in air (favouring the surface recombination mechanisms). The model for PPC in individual nanowires presented here illustrates the intrinsic potential of metal oxide nanowires to develop optoelectronic devices or optochemical sensors with better and new performances.

  16. Influence of the shell thickness and charge distribution on the effective interaction between two like-charged hollow spheres.

    Science.gov (United States)

    Angelescu, Daniel G; Caragheorgheopol, Dan

    2015-10-14

    The mean-force and the potential of the mean force between two like-charged spherical shells were investigated in the salt-free limit using the primitive model and Monte Carlo simulations. Apart from an angular homogeneous distribution, a discrete charge distribution where point charges localized on the shell outer surface followed an icosahedral arrangement was considered. The electrostatic coupling of the model system was altered by the presence of mono-, trivalent counterions or small dendrimers, each one bearing a net charge of 9 e. We analyzed in detail how the shell thickness and the radial and angular distribution of the shell charges influenced the effective interaction between the shells. We found a sequence of the potential of the mean force similar to the like-charged filled spheres, ranging from long-range purely repulsive to short-range purely attractive as the electrostatic coupling increased. Both types of potentials were attenuated and an attractive-to-repulsive transition occurred in the presence of trivalent counterions as a result of (i) thinning the shell or (ii) shifting the shell charge from the outer towards the inner surface. The potential of the mean force became more attractive with the icosahedrally symmetric charge model, and additionally, at least one shell tended to line up with 5-fold symmetry axis along the longest axis of the simulation box at the maximum attraction. The results provided a basic framework of understanding the non-specific electrostatic origin of the agglomeration and long-range assembly of the viral nanoparticles.

  17. Centrifuge separation effect on bacterial indicator reduction in dairy manure.

    Science.gov (United States)

    Liu, Zong; Carroll, Zachary S; Long, Sharon C; Roa-Espinosa, Aicardo; Runge, Troy

    2017-04-15

    Centrifugation is a commonly applied separation method for manure processing on large farms to separate solids and nutrients. Pathogen reduction is also an important consideration for managing manure. Appropriate treatment reduces risks from pathogen exposure when manure is used as soil amendments or the processed liquid stream is recycled to flush the barn. This study investigated the effects of centrifugation and polymer addition on bacterial indicator removal from the liquid fraction of manure slurries. Farm samples were taken from a manure centrifuge processing system. There were negligible changes of quantified pathogen indicator concentrations in the low-solids centrate compared to the influent slurry. To study if possible improvements could be made to the system, lab scale experiments were performed investigating a range of g-forces and flocculating polymer addition. The results demonstrated that polymer addition had a negligible effect on the indicator bacteria levels when centrifuged at high g forces. However, the higher g force centrifugation was capable of reducing bacterial indicator levels up to two-log 10 in the liquid stream of the manure, although at speeds higher than typical centrifuge operations currently used for manure processing applications. This study suggests manure centrifuge equipment could be redesigned to provide pathogen reduction to meet emerging issues, such as zoonotic pathogen control. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. Intrinsic Charge Transport in Organic Field-Effect Transistors

    Science.gov (United States)

    Podzorov, Vitaly

    2005-03-01

    Organic field-effect transistors (OFETs) are essential components of modern electronics. Despite the rapid progress of organic electronics, understanding of fundamental aspects of the charge transport in organic devices is still lacking. Recently, the OFETs based on highly ordered organic crystals have been fabricated with innovative techniques that preserve the high quality of single-crystal organic surfaces. This technological progress facilitated the study of transport mechanisms in organic semiconductors [1-4]. It has been demonstrated that the intrinsic polaronic transport, not dominated by disorder, with a remarkably high mobility of ``holes'' μ = 20 cm^2/Vs can be achieved in these devices at room temperature [4]. The signatures of the intrinsic polaronic transport are the anisotropy of the carrier mobility and an increase of μ with cooling. These and other aspects of the charge transport in organic single-crystal FETs will be discussed. Co-authors are Etienne Menard, University of Illinois at Urbana Champaign; Valery Kiryukhin, Rutgers University; John Rogers, University of Illinois at Urbana Champaign; Michael Gershenson, Rutgers University. [1] V. Podzorov et al., Appl. Phys. Lett. 82, 1739 (2003); ibid. 83, 3504 (2003). [2] V. C. Sundar et al., Science 303, 1644 (2004). [3] R. W. I. de Boer et al., Phys. Stat. Sol. (a) 201, 1302 (2004). [4] V. Podzorov et al., Phys. Rev. Lett. 93, 086602 (2004).

  19. Working Group 2 summary: Space charge effects in bending systems

    International Nuclear Information System (INIS)

    Bohn, C.L.; Emma, P.J.

    2000-01-01

    At the start of the Workshop, the authors asked the Working Group 2 participants to concentrate on three basic goals: (1) survey the status of how comprehensively the physics concerning space-charge effects in bends is understood and how complete is the available ensemble of analytic and computational tools; (2) guided by data from experiments and operational experience, identify sources of, and cures for, beam degradation; and (3) review space-charge physics in rings and the limitations it introduces. As the Workshop unfolded, the third goal naturally folded into the other two goals, and these goals, they believe, were fulfilled in that the Working Group was able to compile an end product consisting of a set of recommendations for potentially fruitful future work. This summary constitutes an overview of the deliberations of the Working Group, and it is their hope that the summary clarifies the motivation for the recommended work listed at the end. The summary is organized according to the two aforementioned goals, and the prime topics of discussion appear as subsections under these goals

  20. Modeling of the charge-state separation at ITEP experimental facility for material science based on a Bernas ion source.

    Science.gov (United States)

    Barminova, H Y; Saratovskyh, M S

    2016-02-01

    The experiment automation system is supposed to be developed for experimental facility for material science at ITEP, based on a Bernas ion source. The program CAMFT is assumed to be involved into the program of the experiment automation. CAMFT is developed to simulate the intense charged particle bunch motion in the external magnetic fields with arbitrary geometry by means of the accurate solution of the particle motion equation. Program allows the consideration of the bunch intensity up to 10(10) ppb. Preliminary calculations are performed at ITEP supercomputer. The results of the simulation of the beam pre-acceleration and following turn in magnetic field are presented for different initial conditions.

  1. Species separation and kinetic effects in collisional plasma shocks

    Energy Technology Data Exchange (ETDEWEB)

    Bellei, C., E-mail: bellei1@llnl.gov; Wilks, S. C.; Amendt, P. A. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 (United States); Rinderknecht, H.; Zylstra, A.; Rosenberg, M.; Sio, H.; Li, C. K.; Petrasso, R. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2014-05-15

    The properties of collisional shock waves propagating in uniform plasmas are studied with ion-kinetic calculations, in both slab and spherical geometry and for the case of one and two ion species. Despite the presence of an electric field at the shock front—and in contrast to the case where an interface is initially present [C. Bellei et al., Phys. Plasmas 20, 044702 (2013)]—essentially no ion reflection at the shock front is observed due to collisions, with a probability of reflection ≲10{sup −4} for the cases presented. A kinetic two-ion-species spherical convergent shock is studied in detail and compared against an average-species calculation, confirming effects of species separation and differential heating of the ion species at the shock front. The effect of different ion temperatures on the DT and D{sup 3}He fusion reactivity is discussed in the fluid limit and is estimated to be moderately important.

  2. Charge Transfer and Support Effects in Heterogeneous Catalysis

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-12-21

    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

  3. Contributions of conduction band offset to the enhanced separation efficiency of photoinduced charges for SrTiO3/Bi2O3 heterojunction semiconductor

    International Nuclear Information System (INIS)

    Zhang, Zhenlong; Zhu, Jichun; Li, Shengjun; Mao, Yanli

    2014-01-01

    SrTiO 3 /Bi 2 O 3 heterojunction semiconductor was prepared and characterized by X-ray diffraction, UV–vis absorption spectrum, and scanning electron microscope, surface photovoltage spectroscopy, and photoluminescence spectroscopy. The surface photovoltage spectra indicate that the separation efficiency of photoinduced charges for SrTiO 3 /Bi 2 O 3 was enhanced compared with that of SrTiO 3 or Bi 2 O 3 . The energy band diagram of SrTiO 3 /Bi 2 O 3 heterojunction was directly determined with X-ray photoelectron spectroscopy, and the conduction band offset between SrTiO 3 and Bi 2 O 3 was quantified to be 0.28±0.03 eV. The photoluminescence spectra display that the recombination rate of photoinduced carriers for SrTiO 3 /Bi 2 O 3 decreases compared with that of SrTiO 3 or Bi 2 O 3 , which is mainly due to the energy levels matching between them. Therefore the enhanced separation efficiency of photoinduced charges is resulting from the energy difference between the conduction band edges of SrTiO 3 and Bi 2 O 3 . -- Graphical abstract: Enhanced separation efficiency for SrTiO 3 /Bi 2 O 3 is resulting from the energy difference between the conduction band edges. Highlights: ●Heterojunction semiconductor of SrTiO 3 /Bi 2 O 3 was prepared. ●SrTiO 3 /Bi 2 O 3 presents enhanced separation efficiency. ●Conduction band offset between SrTiO 3 and Bi 2 O 3 is quantified. ●Recombination rate of SrTiO 3 /Bi 2 O 3 decreases compared with single phases

  4. Geometrical effects on the airfoil flow separation and transition

    KAUST Repository

    Zhang, Wei

    2015-04-25

    We present results from direct numerical simulations (DNS) of incompressible flow over two airfoils, NACA-4412 and NACA-0012-64, to investigate the effects of the airfoil geometry on the flow separation and transition patterns at Re=104 and 10 degrees incidence. The two chosen airfoils are geometrically similar except for maximum camber (respectively 4%C and 0 with C the chord length), which results in a larger projection area with respect to the incoming flow for the NACA-4412 airfoil, and a larger leeward surface curvature at the leading edge for the NACA-0012-64 airfoil. The governing equations are discretized using an energy conservative fourth-order spatial discretization scheme. An assessment on the two-point correlation indicates that a spanwise domain size of 0.8C is sufficiently large for the present simulations. We discuss flow separation at the airfoil leading edge, transition of the separated shear layer to three-dimensional flow and subsequently to turbulence. Numerical results reveal a stronger adverse pressure gradient field in the leading edge region of the NACA-0012-64 airfoil due to the rapidly varying surface curvature. As a result, the flow experiences detachment at x/C=0.08, and the separated shear layer transition via Kelvin-Helmholtz mechanism occurs at x/C=0.29 with fully developed turbulent flow around x/C=0.80. These flow development phases are delayed to occur at much downstream positions, respectively, observed around x/C=0.25, 0.71 and 1.15 for the NACA-4412 airfoil. The turbulent intensity, measured by the turbulent fluctuations and turbulent Reynolds stresses, are much larger for NACA-0012-64 from the transition onset until the airfoil trailing edge, while turbulence develops significantly downstream of the trailing edge for the NACA-4412 airfoil. For both airfoils, our DNS results indicate that the mean Reynolds stress u\\'u\\'/U02 reaches its maximum value at a distance from the surface approximately equal to the displacement

  5. Charging effect at grain boundaries of MoS2

    Science.gov (United States)

    Yan, Chenhui; Dong, Xi; Li, Connie H.; Li, Lian

    2018-05-01

    Grain boundaries (GBs) are inherent extended defects in chemical vapor deposited (CVD) transition metal dichalcogenide (TMD) films. Characterization of the atomic structure and electronic properties of these GBs is crucial for understanding and controlling the properties of TMDs via defect engineering. Here, we report the atomic and electronic structure of GBs in CVD grown MoS2 on epitaxial graphene/SiC(0001). Using scanning tunneling microscopy/spectroscopy, we find that GBs mostly consist of arrays of dislocation cores, where the presence of mid-gap states shifts both conduction and valence band edges by up to 1 eV. Our findings demonstrate the first charging effect near GBs in CVD grown MoS2, providing insights into the significant impact GBs can have on materials properties.

  6. Improved solar light stimulated charge separation of g-C3N4 through self-altering acidic treatment

    Science.gov (United States)

    Leong, Kah Hon; Lim, Ping Feng; Sim, Lan Ching; Punia, Varun; Pichiah, Saravanan

    2018-02-01

    Herein, we report the use of acid treatment to treat g-C3N4 nanostructured by a direct and facile synthesis route. The adopted treatment enhanced photoactivity of g-C3N4 and reflected in the removal of recalcitrant organic pollutant, Bisphenol A under direct sunlight. A complete removal of Bisphenol A was attained in a short duration (225 min) as compared to pure g-C3N4. The analysis clearly substantiated the robustness of acid exfoliation that promoted a blue shift, extended the conjugated length of its respective conduction and valance band. It also drastically prolonged the recombination rate of charge carriers, by producing excess of unpaired electrons in the conduction band for active radicals' generation. Thus, this new findings could offer a new sight of self-alteration in improving the photoactivity of complex organic pollutants for sustainable environmental remediation.

  7. Effect of Conjugation Length on Photoinduced Charge-Transfer in π-Conjugated Oligomer-Acceptor Dyads

    KAUST Repository

    Jiang, Junlin

    2017-05-25

    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.

  8. Effect of Conjugation Length on Photoinduced Charge-Transfer in π-Conjugated Oligomer-Acceptor Dyads

    KAUST Repository

    Jiang, Junlin; Alsam, Amani Abdu; Wang, Shanshan; Aly, Shawkat Mohammede; Pan, Zhenxing; Mohammed, Omar F.; Schanze, Kirk S.

    2017-01-01

    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.

  9. Discrete Charge Effects on an Infinitely Long Cylindrical Rod Model

    OpenAIRE

    Agung, Ahmad A. J; Jesudason, Christopher G.

    2011-01-01

    Two methods for determining the potential (\\psi) around a discretely charged rod have been devised. The methods utilize the potential around the continuously charged rod (\\bar{\\psi}) as the reference where \\bar{\\psi} isdetermined by the Poisson-Boltzmann equation. The potential data are used to determine the theoretical radial distribution function (RDF) which is compared with MD simulation data. It is shown that the magnitude of the charge and size parameters very strongly affects the shape ...

  10. 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)

    2016-10-26

    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.

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

    International Nuclear Information System (INIS)

    Lucas, Andrew; Steinberg, Julia

    2016-01-01

    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.

  12. Ion distributions, exclusion coefficients, and separation factors of electrolytes in a charged cylindrical nanopore: a partially perturbative density functional theory study.

    Science.gov (United States)

    Peng, Bo; Yu, Yang-Xin

    2009-10-07

    The structural and thermodynamic properties for charge symmetric and asymmetric electrolytes as well as mixed electrolyte system inside a charged cylindrical nanopore are investigated using a partially perturbative density functional theory. The electrolytes are treated in the restricted primitive model and the internal surface of the cylindrical nanopore is considered to have a uniform charge density. The proposed theory is directly applicable to the arbitrary mixed electrolyte solution containing ions with the equal diameter and different valences. Large amount of simulation data for ion density distributions, separation factors, and exclusion coefficients are used to determine the range of validity of the partially perturbative density functional theory for monovalent and multivalent counterion systems. The proposed theory is found to be in good agreement with the simulations for both mono- and multivalent counterion systems. In contrast, the classical Poisson-Boltzmann equation only provides reasonable descriptions of monovalent counterion system at low bulk density, and is qualitatively and quantitatively wrong in the prediction for the multivalent counterion systems due to its neglect of the strong interionic correlations in these systems. The proposed density functional theory has also been applied to an electrolyte absorbed into a pore that is a model of the filter of a physiological calcium channel.

  13. Quark mass correction to chiral separation effect and pseudoscalar condensate

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Er-dong [State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics,Chinese Academy of Sciences,Beijing 100190 (China); Kavli Institute of Theoretical Physics China, Chinese Academy of Sciences,Beijing 100190 (China); Lin, Shu [School of Physics and Astronomy, Sun Yat-Sen University,No 2 University Road, Zhuhai 519082 (China)

    2017-01-25

    We derived an analytic structure of the quark mass correction to chiral separation effect (CSE) in small mass regime. We confirmed this structure by a D3/D7 holographic model study in a finite density, finite magnetic field background. The quark mass correction to CSE can be related to correlators of pseudo-scalar condensate, quark number density and quark condensate in static limit. We found scaling relations of these correlators with spatial momentum in the small momentum regime. They characterize medium responses to electric field, inhomogeneous quark mass and chiral shift. Beyond the small momentum regime, we found existence of normalizable mode, which possibly leads to formation of spiral phase. The normalizable mode exists beyond a critical magnetic field, whose magnitude decreases with quark chemical potential.

  14. Overview of CSNI separate effects tests validation matrix

    Energy Technology Data Exchange (ETDEWEB)

    Aksan, N. [Paul Scherrer Institute, Villigen (Switzerland); Auria, F.D. [Univ. of Pisa (Italy); Glaeser, H. [Gesellschaft fuer anlagen und Reaktorsicherheit, (GRS), Garching (Germany)] [and others

    1995-09-01

    An internationally agreed separate effects test (SET) Validation Matrix for thermal-hydraulic system codes has been established by a sub-group of the Task Group on Thermal Hydraulic System Behaviour as requested by the OECD/NEA Committee on Safety of Nuclear Installations (SCNI) Principal Working Group No. 2 on Coolant System Behaviour. The construction of such a Matrix is an attempt to collect together in a systematic way the best sets of openly available test data for code validation, assessment and improvement and also for quantitative code assessment with respect to quantification of uncertainties to the modeling of individual phenomena by the codes. The methodology, that has been developed during the process of establishing CSNI-SET validation matrix, was an important outcome of the work on SET matrix. In addition, all the choices which have been made from the 187 identified facilities covering the 67 phenomena will be investigated together with some discussions on the data base.

  15. Overview PWR-Blowdown Heat Transfer Separate-Effects Program

    International Nuclear Information System (INIS)

    White, J.D.

    1978-01-01

    The ORNL Pressurized Water Reactor Blowdown Heat Transfer Program (PWR-BDHT) is a separate-effects experimental study of thermal-hydraulic phenomena occurring during the first 20 sec of a hypothetical LOCA. Specific objectives include the determination, for a wide range of parameters, of time to CHF and the following variables for both pre- and post-CHF: heat fluxes, ΔT (temperature difference between pin surface and fluid), heat transfer coefficients, and local fluid properties. A summary of the most interesting results from the program obtained during the past year is presented. These results are in the area of: (1) RELAP verification, (2) electric pin calibration, (3) time to critical heat flux (CHF), (4) heat transfer coefficient comparisons, and (5) nuclear fuel pin simulation

  16. PWR-blowdown heat transfer separate effects program

    International Nuclear Information System (INIS)

    Thomas, D.G.

    1976-01-01

    The ORNL Pressurized-Water Reactor Blowdown Heat Transfer (PWR-BDHT) Program is an experimental separate-effects study of the relations among the principal variables that can alter the rate of blowdown, the presence of flow reversal and rereversal, time delay to critical heat flux, the rate at which dryout progresses, and similar time-related functions that are important to LOCA analysis. Primary test results are obtained from the Thermal-Hydraulic Test Facility (THTF). Supporting experiments are carried out in several additional test loops - the Forced Convection Test Facility (FCTF), an air-water loop, a transient steam-water loop, and a low-temperature water mockup of the THTF heater rod bundle. The studies to date are described

  17. Separating form factor and nuclear model effects in quasielastic neutrino-nucleus scattering

    Science.gov (United States)

    Wieske, Joseph

    2017-09-01

    When studying neutrino oscillations an understanding of charged current quasielastic (CCQE) neutrino-nucleus scattering is imperative. This interaction depends on a nuclear model as well as knowledge of form factors. In the past, CCQE data from the MiniBooNE experiment was analyzed assuming the Relativistic Fermi Gas (RFG) nuclear model, an axial dipole form factor in, and using the the z-expansion for the axial form factor in. We present the first analysis that combines a non-RFG nuclear model, in particular the Correlated Fermi Gas nuclear model (CFG) of, and the z expansion for the axial form factor. This will allow us to separate form factor and nuclear model effects in CCQE scattering. This project was supported through the Wayne State University REU program under NSF Grant PHY-1460853 and by the DOE Grant DE-SC0007983.

  18. Surface charge effects in protein adsorption on nanodiamonds.

    Science.gov (United States)

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

    2015-03-19

    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.

  19. Developing Effective Separation of Feldspar and Quartz While Recycling Tailwater by HF Pretreatment

    Directory of Open Access Journals (Sweden)

    Weiqing Wang

    2018-04-01

    Full Text Available The effect of hydrofluoric acid (HF pretreatment on flotation of feldspar and quartz using dodecylamine (DDA as collector was investigated by micro-flotation, zeta potential, pyrene fluorescence spectroscopy, attenuated total reflection flourier transformed infrared spectroscopy (ATR-FTIR, scanning electron microscope (SEM, X-ray photoelectron spectroscopy (XPS and bench scale flotation. The micro-flotation tests revealed that there was little difference in the flotation of feldspar and quartz at pH 2, using H2SO4 as pH regulator. After HF pretreatment, the floatability of feldspar significantly increased while the floatability of quartz showed no change. HF pretreatment resulted in leaching of SiO2 and enrichment of Na, K and Al on the feldspar surface. Consequently, the negative surface charge of feldspar increased at pH 2, which allowed for the flotation separation of the feasible minerals. This took place via an increased electrostatic adsorption between DDA and Na, K, Al on the feldspar surface, which effectively increased its hydrophobicity and as a result, improved the floatability of feldspar. An alternative process which exhibited effective separation of quartz and feldspar while recycling the tailwater from the flotation was proposed.

  20. Meissner effect for axially symmetric charged black holes

    Science.gov (United States)

    Gürlebeck, Norman; Scholtz, Martin

    2018-04-01

    In our previous work [N. Gürlebeck and M. Scholtz, Phys. Rev. D 95, 064010 (2017), 10.1103/PhysRevD.95.064010], we have shown that electric and magnetic fields are expelled from the horizons of extremal, stationary and axially symmetric uncharged black holes; this is called the Meissner effect for black holes. Here, we generalize this result in several directions. First, we allow that the black hole carries charge, which requires a generalization of the definition of the Meissner effect. Next, we introduce the notion of almost isolated horizons, which is weaker than the usual notion of isolated horizons, since the geometry of the former is not necessarily completely time independent. Moreover, we allow the horizon to be pierced by strings, thereby violating the usual assumption on the spherical topology made in the definition of the weakly isolated horizon. Finally, we spell out in detail all assumptions entering the proof and show that the Meissner effect is an inherent property of black holes even in full nonlinear theory.

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

    Indian Academy of Sciences (India)

    It is shown that the scattering of polaronic charge carriers and bosonic Cooper pairs at acoustic and optical phonons are responsible for the charge carrier mobility above and below the PG temperature. We show that the energy scales of the binding energies of large polarons and polaronic Cooper pairs can be identified by ...

  2. Influence of Blend Morphology and Energetics on Charge Separation and Recombination Dynamics in Organic Solar Cells Incorporating a Nonfullerene Acceptor

    KAUST Repository

    Cha, Hyojung; Wheeler, Scot; Holliday, Sarah; Dimitrov, Stoichko D.; Wadsworth, Andrew; Lee, Hyun Hwi; Baran, Derya; McCulloch, Iain; Durrant, James R.

    2017-01-01

    Nonfullerene acceptors (NFAs) in blends with highly crystalline donor polymers have been shown to yield particularly high device voltage outputs, but typically more modest quantum yields for photocurrent generation as well as often lower fill factors (FF). In this study, we employ transient optical and optoelectronic analysis to elucidate the factors determining device photocurrent and FF in blends of the highly crystalline donor polymer PffBT4T-2OD with the promising NFA FBR or the more widely studied fullerene acceptor PC71BM. Geminate recombination losses, as measured by ultrafast transient absorption spectroscopy, are observed to be significantly higher for PffBT4T-2OD:FBR blends. This is assigned to the smaller LUMO-LUMO offset of the PffBT4T-2OD:FBR blends relative to PffBT4T-2OD:PC71BM, resulting in the lower photocurrent generation efficiency obtained with FBR. Employing time delayed charge extraction measurements, these geminate recombination losses are observed to be field dependent, resulting in the lower FF observed with PffBT4T-2OD:FBR devices. These data therefore provide a detailed understanding of the impact of acceptor design, and particularly acceptor energetics, on organic solar cell performance. Our study concludes with a discussion of the implications of these results for the design of NFAs in organic solar cells.

  3. Influence of Blend Morphology and Energetics on Charge Separation and Recombination Dynamics in Organic Solar Cells Incorporating a Nonfullerene Acceptor

    KAUST Repository

    Cha, Hyojung

    2017-11-27

    Nonfullerene acceptors (NFAs) in blends with highly crystalline donor polymers have been shown to yield particularly high device voltage outputs, but typically more modest quantum yields for photocurrent generation as well as often lower fill factors (FF). In this study, we employ transient optical and optoelectronic analysis to elucidate the factors determining device photocurrent and FF in blends of the highly crystalline donor polymer PffBT4T-2OD with the promising NFA FBR or the more widely studied fullerene acceptor PC71BM. Geminate recombination losses, as measured by ultrafast transient absorption spectroscopy, are observed to be significantly higher for PffBT4T-2OD:FBR blends. This is assigned to the smaller LUMO-LUMO offset of the PffBT4T-2OD:FBR blends relative to PffBT4T-2OD:PC71BM, resulting in the lower photocurrent generation efficiency obtained with FBR. Employing time delayed charge extraction measurements, these geminate recombination losses are observed to be field dependent, resulting in the lower FF observed with PffBT4T-2OD:FBR devices. These data therefore provide a detailed understanding of the impact of acceptor design, and particularly acceptor energetics, on organic solar cell performance. Our study concludes with a discussion of the implications of these results for the design of NFAs in organic solar cells.

  4. Charge Effects on the Efflorescence in Single Levitated Droplets.

    Science.gov (United States)

    Hermann, Gunter; Zhang, Yan; Wassermann, Bernhard; Fischer, Henry; Quennet, Marcel; Rühl, Eckart

    2017-09-14

    The influence of electrical excess charges on the crystallization from supersaturated aqueous sodium chloride solutions is reported. This is accomplished by efflorescence studies on single levitated microdroplets using optical and electrodynamic levitation. Specifically, a strong increase in efflorescence humidity is observed as a function of the droplet's negative excess charge, ranging up to -2.1 pC, with a distinct threshold behavior, increasing the relative efflorescence humidity, at which spontaneous nucleation occurs, from 44% for the neutral microparticle to 60%. These findings are interpreted by using molecular dynamics simulations for determining plausible structural patterns located near the particle surface that could serve as suitable precursors for the formation of critical clusters overcoming the nucleation barrier. These results, facilitating heterogeneous nucleation in the case of negatively charged microparticles, are compared to recent work on charge-induced nucleation of neat supercooled water, where a distinctly different nucleation behavior as a function of droplet charge has been observed.

  5. Effects of additives on solidification of API separator sludge.

    Science.gov (United States)

    Faschan, A; Tittlebaum, M; Cartledge, F; Eaton, H

    1991-08-01

    API separator sludge was solidified with various combinations of binders and absorbent soil additives. The binders utilized were Type I Portland Cement, Type C Flyash, and a 1:1 combination of the two. The soil additives used were bentonite, diatomite, Fuller's earth, and two brands of chemically altered bentonites, or organoclays. The effectiveness of the solidification materials was based on their effect on the physical and leaching characteristics of the sludge.It was determined the Portland cement and combination binders provided the sludge with adequate physical and strength characteristics. It was also determined the affinity of each additive for water had an important influence on the physical characteristics of the solidified sludge. The results of the leaching procedure indicated the binders alone reduced the leachability of organic constituents from the sludge by 1/5 to 1/10. It appeared the use of the additives with the binders may have further reduced the leachability of constituents from sludge, with the incorporation of the organoclay additives further reducing leachability by up to 1/2. Also, it appeared the absorbing capacity of the additives was directly related to their ability to reduce the leachability of organic constituents from the sludge.

  6. Effect of Coulomb scattering from trapped charges on the mobility in an organic field-effect transistor

    NARCIS (Netherlands)

    Sharma, A.; Janssen, N.M.A.; Matthijssen, S.J.G.; de Leeuw, D.M.; Kemerink, M.; Bobbert, P.A.

    2011-01-01

    We investigate the effect of Coulomb scattering from trapped charges on the mobility in the two-dimensional channel of an organic field-effect transistor. The number of trapped charges can be tuned by applying a prolonged gate bias. Surprisingly, after increasing the number of trapped charges to a

  7. High-Performance Oligomeric Catholytes for Effective Macromolecular Separation in Nonaqueous Redox Flow Batteries.

    Science.gov (United States)

    Hendriks, Koen H; Robinson, Sophia G; Braten, Miles N; Sevov, Christo S; Helms, Brett A; Sigman, Matthew S; Minteer, Shelley D; Sanford, Melanie S

    2018-02-28

    Nonaqueous redox flow batteries (NRFBs) represent an attractive technology for energy storage from intermittent renewable sources. In these batteries, electrical energy is stored in and extracted from electrolyte solutions of redox-active molecules (termed catholytes and anolytes) that are passed through an electrochemical flow cell. To avoid battery self-discharge, the anolyte and catholyte solutions must be separated by a membrane in the flow cell. This membrane prevents crossover of the redox active molecules, while simultaneously allowing facile transport of charge-balancing ions. A key unmet challenge for the field is the design of redox-active molecule/membrane pairs that enable effective electrolyte separation while maintaining optimal battery properties. Herein, we demonstrate the development of oligomeric catholytes based on tris(dialkylamino)cyclopropenium (CP) salts that are specifically tailored for pairing with size-exclusion membranes composed of polymers of intrinsic microporosity (PIMs). Systematic studies were conducted to evaluate the impact of oligomer size/structure on properties that are crucial for flow battery performance, including cycling stability, charge capacity, solubility, electron transfer kinetics, and crossover rates. These studies have led to the identification of a CP-derived tetramer in which these properties are all comparable, or significantly improved, relative to the monomeric counterpart. Finally, a proof-of-concept flow battery is demonstrated by pairing this tetrameric catholyte with a PIM membrane. After 6 days of cycling, no crossover is detected, demonstrating the promise of this approach. These studies provide a template for the future design of other redox-active oligomers for this application.

  8. Ewald Electrostatics for Mixtures of Point and Continuous Line Charges.

    Science.gov (United States)

    Antila, Hanne S; Tassel, Paul R Van; Sammalkorpi, Maria

    2015-10-15

    Many charged macro- or supramolecular systems, such as DNA, are approximately rod-shaped and, to the lowest order, may be treated as continuous line charges. However, the standard method used to calculate electrostatics in molecular simulation, the Ewald summation, is designed to treat systems of point charges. We extend the Ewald concept to a hybrid system containing both point charges and continuous line charges. We find the calculated force between a point charge and (i) a continuous line charge and (ii) a discrete line charge consisting of uniformly spaced point charges to be numerically equivalent when the separation greatly exceeds the discretization length. At shorter separations, discretization induces deviations in the force and energy, and point charge-point charge correlation effects. Because significant computational savings are also possible, the continuous line charge Ewald method presented here offers the possibility of accurate and efficient electrostatic calculations.

  9. Surface charge effects in protein adsorption on nanodiamonds

    Science.gov (United States)

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

    2015-03-01

    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

  10. Effective charge model in the theory of infrared intensities and its application for study of charge di.stribution in the molecules of organometallic compounds

    International Nuclear Information System (INIS)

    Aleksanyan, V.T.; Samvelyan, S.Kh.

    1984-01-01

    General principles of plotting the parametric theory of IR spectrum intensities of polyatomic molecules are outlined. The development of the effective charges model in this theory is considered and the mathematical formalism of the first approximation of the method of effective atom charges is described in detail. The results of calculations of charges distribution in the Mo(CO) 6 , W(CO) 6 , Cp 2 V, Cp 2 Ru and others (Cp-cyclopentadiene), performed in the frame work of the outlined scheme are presented. It is shown that in the investigated carbonyles the effective charge on oxygen and metal atoms is negative, on carbon atom - positive. In dicyclopentavienyl complexes the effective charge on the metal atom is positive and is not over 0.6e; charge values on hydrogen and carbon atoms do not exceed, 0.10-0.15e. The notions of ''electrovalence'' of coordination bond and charge distribution in the case of metallocenes are not correlated

  11. Effective-range function methods for charged particle collisions

    Science.gov (United States)

    Gaspard, David; Sparenberg, Jean-Marc

    2018-04-01

    Different versions of the effective-range function method for charged particle collisions are studied and compared. In addition, a novel derivation of the standard effective-range function is presented from the analysis of Coulomb wave functions in the complex plane of the energy. The recently proposed effective-range function denoted as Δℓ [Ramírez Suárez and Sparenberg, Phys. Rev. C 96, 034601 (2017), 10.1103/PhysRevC.96.034601] and an earlier variant [Hamilton et al., Nucl. Phys. B 60, 443 (1973), 10.1016/0550-3213(73)90193-4] are related to the standard function. The potential interest of Δℓ for the study of low-energy cross sections and weakly bound states is discussed in the framework of the proton-proton S10 collision. The resonant state of the proton-proton collision is successfully computed from the extrapolation of Δℓ instead of the standard function. It is shown that interpolating Δℓ can lead to useful extrapolation to negative energies, provided scattering data are known below one nuclear Rydberg energy (12.5 keV for the proton-proton system). This property is due to the connection between Δℓ and the effective-range function by Hamilton et al. that is discussed in detail. Nevertheless, such extrapolations to negative energies should be used with caution because Δℓ is not analytic at zero energy. The expected analytic properties of the main functions are verified in the complex energy plane by graphical color-based representations.

  12. Spin dynamics of light-induced charge separation in composites of semiconducting polymers and PC60BM revealed using Q-band pulse EPR.

    Science.gov (United States)

    Lukina, E A; Suturina, E; Reijerse, E; Lubitz, W; Kulik, L V

    2017-08-23

    Light-induced processes in composites of semiconducting polymers and fullerene derivatives have been widely studied due to their usage as active layers of organic solar cells. However the process of charge separation under light illumination - the key process of an organic solar cell is not well understood yet. Here we report a Q-band pulse electron paramagnetic resonance study of composites of the fullerene derivative PC 60 BM ([6,6]-phenyl-C 61 -butyric acid methyl ester) with different p-type semiconducting polymers regioregular and regiorandom P3HT (poly(3-hexylthiophene-2,5-diyl), MEH-PPV (poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene]), PCDTBT (poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)]), PTB7 (poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl}))), resulting in a detailed description of the in-phase laser flash-induced electron spin echo (ESE) signal. We found that in organic donor-acceptor composites the laser flash simultaneously induces species of two types: a polymer˙ + /fullerene˙ - spin-correlated polaron pair (SCPP) with an initial singlet spin state and (nearly) free polymer˙ + and fullerene˙ - species with non-equilibrium spin polarization. Species of the first type (SCPP) are well-known for polymer/fullerene blends and are usually associated with a charge-separated state. Also, spin polarization of long-living free species (polarons in deep traps) is affected by the laser flash, which is the third contribution to the flash-induced ESE signal. A protocol for extracting the in-phase ESE signal of the SCPP based on the dependence of the microwave nutation frequency on the strength of the spin coupling within the polaron pair was developed. Nutation experiments revealed an unusual pattern of the SCPP in RR-P3HT/PC 60 BM composites, from which the strength of the exchange interaction between the polymer

  13. Spacecraft charging and related effects during Halley encounter

    International Nuclear Information System (INIS)

    Young, D.T.

    1983-01-01

    Hypervelocity (69 km/s) impact of cometary material with surfaces of the GIOTTO spacecraft will induce a number of spurious and possibly harmful phenomena. The most serious of these is likely to be spacecraft charging that results from impact-produced plasma distributions surrounding GIOTTO. The ESA Plasma Environment Working Group, whose studies are the basis for this report, finds that charging may become significant within approx. 10 5 km of the nucleus where potentials of approx. = +20 V are to be expected. In addition to spacecraft charging, impact produced plasma may interfere with in situ plasma measurements, particularly those of ion plasma analyzers and mass spectrometers

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

    International Nuclear Information System (INIS)

    Trizac, Emmanuel; Aubouy, Miguel; Bocquet, Lyderic

    2003-01-01

    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

  15. The Effect of Voltage Charging on the Transport Properties of Gold Nanotube Membranes.

    Science.gov (United States)

    Experton, Juliette; Martin, Charles R

    2018-05-01

    Porous membranes are used in chemical separations and in many electrochemical processes and devices. Research on the transport properties of a unique class of porous membranes that contain monodisperse gold nanotubes traversing the entire membrane thickness is reviewed here. These gold nanotubes can act as conduits for ionic and molecular transports through the membrane. Because the tubes are electronically conductive, they can be electrochemically charged by applying a voltage to the membrane. How this "voltage charging" affects the transport properties of gold nanotube membranes is the subject of this Review. Experiments showing that voltage charging can be used to reversibly switch the membrane between ideally cation- and anion-transporting states are reviewed. Voltage charging can also be used to enhance the ionic conductivity of gold nanotube membranes. Finally, voltage charging to accomplish electroporation of living bacteria as they pass through gold nanotube membranes is reviewed. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Further evaluation of the CSNI separate effect test activity

    Energy Technology Data Exchange (ETDEWEB)

    D`Auria, F.; Aksan, S.N.; Glaeser, H. [and others

    1995-09-01

    An internationally agreed Separate Effect Test (SET) Validation Matrix for the thermalhydraulic system codes has been established by a subgroup of the Task Group on Thermalhydraulic System Behaviour as requested by OECD/NEA Committee on the Safety of Nuclear Installations (CSNI) Principal Working Group No. 2 on Coolant System Behavior. The construction of such matrix constituted an attempt to collect together in a systematic way the best sets of openly available test data to select for code validation. As a final result, 67 phenomena have been identified and characterized, roughly 200 facilities have been considered and more than 1000 experiments have been selected as useful for the validation of the codes. The objective of the present paper is to provide additional evaluation of the obtained data base and to supply an a-posteriori judgement in relation to (a) the data base adequacy, (b) the phenomenon, and (c) the need for additional experiments. This has been provided independently by each of the authors. The main conclusions are that large amount of data are available for certain popular phenomena e.g. heat transfer, but data are severely lacking in more esoteric areas e.g. for characterizing phenomena such as parallel channel instability and boron mixing and transport.

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

    Indian Academy of Sciences (India)

    rate. Time-dependent density functional theory calculations have been performed to understand the observed spectroscopic results. Keywords. Intramolecular charge transfer; absorption and fluorescence; time resolved fluorescence measurements; acid concentration dependence; time-dependent density functional theory.

  18. Evidence for charge exchange effects in electronic excitations in Al by slow singly charged He ions

    Energy Technology Data Exchange (ETDEWEB)

    Riccardi, P., E-mail: Pierfrancesco.riccardi@fis.unical.it [Dipartimento di Fisica, Università della Calabria and INFN Gruppo collegato di Cosenza, Via P. Bucci cubo 31C, 87036 – Arcavacata di Rende, Cosenza (Italy); Sindona, A. [Dipartimento di Fisica, Università della Calabria and INFN Gruppo collegato di Cosenza, Via P. Bucci cubo 31C, 87036 – Arcavacata di Rende, Cosenza (Italy); Dukes, C.A. [Laboratory for Astrophysics and Surface Physics, Materials Science and Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States)

    2016-09-01

    We report on experiments of secondary electron emission in the interaction of helium ions with aluminum surfaces. Comparison between the electron emission induced by the impact of {sup 3}He{sup +} and {sup 4}He{sup +} on Al illustrates similarities and differences between the two projectiles. The intensity of emission shows the same dependence on velocity for the two isotopes, showing that KEE yields for helium ions impact on Al are dominated by direct excitation of valence electrons and not by electron promotion. Electron promotion and charge transfer processes are unambiguously identified by the observation of Auger electron emission from Al, at energies below the excitation threshold of Al–Al collisions, indicating energy losses for the projectiles higher than those commonly considered.

  19. Effect of charging on silicene with alkali metal atom adsorption

    Science.gov (United States)

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

    2018-02-01

    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.

  20. Interference effects in the nonlinear charge density wave dynamics

    International Nuclear Information System (INIS)

    Jelcic, D.; Batistic, I.; Bjelis, A.

    1987-12-01

    The main features of the nonlinear charge density wave transport in the external dc-ac field are shown to be the natural consequences of resonant phase slip diffusion. This process is treated numerically within the time dependent Landau-Ginzburg model, developed by Gor'kov. The resonances in the ac field are manifested as Shapiro steps in I-V characteristics, present at all rational ratios of internal frequency of current oscillations and external ac frequency. The origin of Shapiro steps, as well as their forms and heights, are cosidered in detail. In particular, it is shown that close to resonances the phase slip voltage acquires a highly nonsinusoidal modulation which leads to the appearance of low frequency and satellite peaks in the Fourier spectrum. Taking into account the interference of adjacent phase slips and the segment or domain structure of physical samples, we interpret the finite width of steps, side wings, synchronization, incomplete and complete mode locking and some other effects observed in numerous experiments on NbSe 3 and other CDW materials. (author). 36 refs, 12 figs

  1. Elucidating the charge carrier separation and working mechanism of CH3NH3PbI(3-x)Cl(x) perovskite solar cells.

    Science.gov (United States)

    Edri, Eran; Kirmayer, Saar; Mukhopadhyay, Sabyasachi; Gartsman, Konstantin; Hodes, Gary; Cahen, David

    2014-03-11

    Developments in organic-inorganic lead halide-based perovskite solar cells have been meteoric over the last 2 years, with small-area efficiencies surpassing 15%. We address the fundamental issue of how these cells work by applying a scanning electron microscopy-based technique to cell cross-sections. By mapping the variation in efficiency of charge separation and collection in the cross-sections, we show the presence of two prime high efficiency locations, one at/near the absorber/hole-blocking-layer, and the second at/near the absorber/electron-blocking-layer interfaces, with the former more pronounced. This 'twin-peaks' profile is characteristic of a p-i-n solar cell, with a layer of low-doped, high electronic quality semiconductor, between a p- and an n-layer. If the electron blocker is replaced by a gold contact, only a heterojunction at the absorber/hole-blocking interface remains.

  2. The effect of charge exchange with neutral deuterium on carbon emission in JET divertor plasmas

    International Nuclear Information System (INIS)

    Maggi, C.; Horton, L.; Summers, H.

    1999-11-01

    High density, low temperature divertor plasma operation in tokamaks results in large neutral deuterium concentrations in the divertor volume. In these conditions, low energy charge transfer reactions between neutral deuterium and the impurity ions can in principle enhance the impurity radiative losses and thus help to reduce the maximum heat load to the divertor target. A quantitative study of the effect of charge exchange on carbon emission is presented, applied to the JET divertor. Total and state selective effective charge exchange recombination rate coefficients were calculated in the collisional radiative picture. These coefficients were coupled to divertor and impurity transport models to study the effect of charge exchange on the measured carbon spectral emission in JET divertor discharges. The sensitivity of the effect of charge exchange to the assumptions in the impurity transport model was also investigated. A reassessment was made of fundamental charge exchange cross section data in support of this study. (author)

  3. Pressure-induced emission band separation of the hybridized local and charge transfer excited state in a TPE-based crystal.

    Science.gov (United States)

    Liu, Xuedan; Li, Aisen; Xu, Weiqing; Ma, Zhiyong; Jia, Xinru

    2018-05-08

    We herein report a newly synthesized simple molecule, named TPE[double bond, length as m-dash]C4, with twisted D-A structure. TPE[double bond, length as m-dash]C4 showed two intrinsic emission bands ascribed to the locally excited (LE) state and the intramolecular charge transfer (ICT) state, respectively. In the crystal state, the LE emission band is usually observed. However, by applying hydrostatic pressure to the powder sample and the single crystal sample of TPE[double bond, length as m-dash]C4, dual-fluorescence (445 nm and 532 nm) was emerged under high pressure, owing to the pressure-induced emission band separation of the hybridized local and charge transfer excited state (HLCT). It is found that the emission of TPE[double bond, length as m-dash]C4 is generally determined by the ratio of the LE state to the ICT state. The ICT emission band is much more sensitive to the external pressure than the LE emission band. The HLCT state leads to a sample with different responsiveness to grinding and hydrostatic pressure. This study is of significance in the molecular design of such D-A type molecules and in the control of photoluminescence features by molecular structure. Such results are expected to pave a new way to further understand the relationship between the D-A molecular structure and stimuli-responsive properties.

  4. 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

    2005-01-01

    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.

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

    International Nuclear Information System (INIS)

    Zhou Yuanxiang; Wang Yunshan; Sun Qinghua; Wang Ninghua

    2009-01-01

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

  6. Effect of homopolymer in polymerization-induced microphase separation process

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jongmin; Saba, Stacey A.; Hillmyer, Marc A.; Kang, Dong-Chang; Seo, Myungeun (IBS-Korea); (KAIST); (UMMN)

    2017-09-01

    We report on the phase separation behaviors of polymerization mixtures containing a polylactide macro-chain transfer agent (PLA-CTA), styrene, divinylbenzene, hydroxyl-terminated PLA (PLA-OH), and a molecular chain transfer agent which enable the ability to tune the pore size of a cross-linked polymer monolith in a facile manner. Cross-linked monoliths were produced from the mixtures via reversible addition-fragmentation chain transfer (RAFT) polymerization and converted into cross-linked porous polymers by selective removal of PLA while retaining the parent morphology. We demonstrate that pore sizes are tunable over a wide range of length scales from the meso- to macroporous regimes by adjusting the ratio of PLA-CTA to PLA-OH in the reaction mixture which causes the phase separation mechanism to change from polymerization-induced microphase separation to polymerization-induced phase separation. The possibility of increasing porosity and inducing simultaneous micro- and macrophase separation was also realized by adjustments in the molar mass of PLA which enabled the synthesis of hierarchically meso- and macroporous polymers.

  7. High resolution separations of charge variants and disulfide isomers of monoclonal antibodies and antibody drug conjugates using ultra-high voltage capillary electrophoresis with high electric field strength.

    Science.gov (United States)

    Henley, W Hampton; He, Yan; Mellors, J Scott; Batz, Nicholas G; Ramsey, J Michael; Jorgenson, James W

    2017-11-10

    Ultra-high voltage capillary electrophoresis with high electric field strength has been applied to the separation of the charge variants, drug conjugates, and disulfide isomers of monoclonal antibodies. Samples composed of many closely related species are difficult to resolve and quantify using traditional analytical instrumentation. High performance instrumentation can often save considerable time and effort otherwise spent on extensive method development. Ideally, the resolution obtained for a given CE buffer system scales with the square root of the applied voltage. Currently available commercial CE instrumentation is limited to an applied voltage of approximately 30kV and a maximum electric field strength of 1kV/cm due to design limitations. The instrumentation described here is capable of safely applying potentials of at least 120kV with electric field strengths over 2000V/cm, potentially doubling the resolution of the best conventional CE buffer/capillary systems while decreasing analysis time in some applications. Separations of these complex mixtures using this new instrumentation demonstrate the potential of ultra-high voltage CE to identify the presence of previously unresolved components and to reduce analysis time for complex mixtures of antibody variants and drug conjugates. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Downstream Effects on Orbiter Leeside Flow Separation for Hypersonic Flows

    Science.gov (United States)

    Buck, Gregory M.; Pulsonetti, Maria V.; Weilmuenster, K. James

    2005-01-01

    Discrepancies between experiment and computation for shuttle leeside flow separation, which came to light in the Columbia accident investigation, are resolved. Tests were run in the Langley Research Center 20-Inch Hypersonic CF4 Tunnel with a baseline orbiter model and two extended trailing edge models. The extended trailing edges altered the wing leeside separation lines, moving the lines toward the fuselage, proving that wing trailing edge modeling does affect the orbiter leeside flow. Computations were then made with a wake grid. These calculations more closely matched baseline experiments. Thus, the present findings demonstrate that it is imperative to include the wake flow domain in CFD calculations in order to accurately predict leeside flow separation for hypersonic vehicles at high angles of attack.

  9. A study of charge symmetry breaking effects in elastic π+-d scattering

    International Nuclear Information System (INIS)

    Rinat, A.S.; Alexander, Y.

    1982-06-01

    We computed external Coulomb and some strong charge symmetry breaking (CSB) effects in π +- d→π +- d. These appear to account for charge asymmetry of differential cross sections, while approximate CSB spoils the agreement. We further report on a critical study of CSB effects extracted from π +- d total cross section differences. (author)

  10. Effective potential in the problem of scattering of three charged particles

    International Nuclear Information System (INIS)

    Kvitsinskii, A.A.; Merkur'ev, S.P.

    1988-01-01

    We study the effective interaction potential in the scattering of a charged particle by a bound state of two other charged particles. Scattering by both the ground and excited states of the target is considered. Explicit representations describing the asymptotic structure of effective potentials are proved

  11. Screening effects in plasma with charged Bose condensate

    International Nuclear Information System (INIS)

    Dolgov, Alexander D.; Lepidi, Angela; Piccinelli, Gabriella

    2009-01-01

    The screening of a Coulomb field of test charge in plasma with a Bose condensate of an electrically charged scalar field is considered. It is found that the screened potential contains several different terms: one decreases as a power of distance (in contrast to the usual exponential Debye screening), and some others oscillate with an exponentially decreasing envelope. A similar phenomenon exists for fermions (Friedel oscillations), but fermionic and bosonic systems have quite different features. Several limiting cases and values of the parameters are considered and the resulting potentials are presented.

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

    DEFF Research Database (Denmark)

    Kuvvetli, Irfan; Budtz-Jørgensen, Carl

    2007-01-01

    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 Cd......Te 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...

  13. Cost-Effectiveness Comparison of Coupler Designs of Wireless Power Transfer for Electric Vehicle Dynamic Charging

    Directory of Open Access Journals (Sweden)

    Weitong Chen

    2016-11-01

    Full Text Available This paper presents a cost-effectiveness comparison of coupler designs for wireless power transfer (WPT, meant for electric vehicle (EV dynamic charging. The design comparison of three common types of couplers is first based on the raw material cost, output power, transfer efficiency, tolerance of horizontal offset, and flux density. Then, the optimal cost-effectiveness combination is selected for EV dynamic charging. The corresponding performances of the proposed charging system are compared and analyzed by both simulation and experimentation. The results verify the validity of the proposed dynamic charging system for EVs.

  14. Evaluation of differences between dual salt-pH gradient elution and mono gradient elution using a thermodynamic model: Simultaneous separation of six monoclonal antibody charge and size variants on preparative-scale ion exchange chromatographic resin.

    Science.gov (United States)

    Lee, Yi Feng; Jöhnck, Matthias; Frech, Christian

    2018-02-21

    The efficiencies of mono gradient elution and dual salt-pH gradient elution for separation of six mAb charge and size variants on a preparative-scale ion exchange chromatographic resin are compared in this study. Results showed that opposite dual salt-pH gradient elution with increasing pH gradient and simultaneously decreasing salt gradient is best suited for the separation of these mAb charge and size variants on Eshmuno ® CPX. Besides giving high binding capacity, this type of opposite dual salt-pH gradient also provides better resolved mAb variant peaks and lower conductivity in the elution pools compared to single pH or salt gradients. To have a mechanistic understanding of the differences in mAb variants retention behaviors of mono pH gradient, parallel dual salt-pH gradient, and opposite dual salt-pH gradient, a linear gradient elution model was used. After determining the model parameters using the linear gradient elution model, 2D plots were used to show the pH and salt dependencies of the reciprocals of distribution coefficient, equilibrium constant, and effective ionic capacity of the mAb variants in these gradient elution systems. Comparison of the 2D plots indicated that the advantage of opposite dual salt-pH gradient system with increasing pH gradient and simultaneously decreasing salt gradient is the noncontinuous increased acceleration of protein migration. Furthermore, the fitted model parameters can be used for the prediction and optimization of mAb variants separation in dual salt-pH gradient and step elution. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 2018. © 2018 American Institute of Chemical Engineers.

  15. Effects of charging and electric field on graphene functionalized with titanium

    International Nuclear Information System (INIS)

    Gürel, H Hakan; Ciraci, S

    2013-01-01

    Titanium atoms are adsorbed to graphene with a significant binding energy and render diverse functionalities to it. Carrying out first-principles calculations, we investigated the effects of charging and static electric field on the physical and chemical properties of graphene covered by Ti adatoms. When uniformly Ti covered graphene is charged positively, its antiferromagnetic ground state changes to ferromagnetic metal and attains a permanent magnetic moment. Static electric field applied perpendicularly causes charge transfer between Ti and graphene, and can induce metal–insulator transition. While each Ti adatom adsorbed to graphene atom can hold four hydrogen molecules with a weak binding, these molecules can be released by charging or applying electric field perpendicularly. Hence, it is demonstrated that charging and applied static electric field induce quasi-continuous and side specific modifications in the charge distribution and potential energy of adatoms absorbed to single-layer nanostructures, resulting in fundamentally crucial effects on their physical and chemical properties. (paper)

  16. Effect of net surface charge on particle sizing and material recognition by using phase Doppler anemometry

    International Nuclear Information System (INIS)

    Zhou Jun; Xie Li

    2011-01-01

    By taking net surface charge into consideration, the scattering field of particles illuminated by dual laser beams of phase Doppler anemometry (PDA) is computed based on Mie's theory, and the effect of net surface charge on the phase-diameter relationship and the phase ratio is studied. It is found that the phase-diameter relationship and the relationship between the phase ratio and the refractive index of charged particles could be significantly different from those of uncharged particles, which would lead to errors in particle sizing and the measurement of refractive indices. A method of recognizing charged particles and determining the value of their surface conductivity, which is related to net surface charge, is proposed by utilizing the effect of net surface charge on the measurement of refractive indices using PDA.

  17. Effect of net surface charge on particle sizing and material recognition by using phase Doppler anemometry

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Jun; Xie Li

    2011-01-20

    By taking net surface charge into consideration, the scattering field of particles illuminated by dual laser beams of phase Doppler anemometry (PDA) is computed based on Mie's theory, and the effect of net surface charge on the phase-diameter relationship and the phase ratio is studied. It is found that the phase-diameter relationship and the relationship between the phase ratio and the refractive index of charged particles could be significantly different from those of uncharged particles, which would lead to errors in particle sizing and the measurement of refractive indices. A method of recognizing charged particles and determining the value of their surface conductivity, which is related to net surface charge, is proposed by utilizing the effect of net surface charge on the measurement of refractive indices using PDA.

  18. 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.

    2012-01-01

    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

  19. The effect of gas release on column separator

    NARCIS (Netherlands)

    Kranenburg, C.

    1974-01-01

    A mathematical model has been considered in which the influence of gas release on transient cavitating flow and column separation in pipel ines is taken into account. A rei iable numerical method has been developed for the computation of the wave propagation and cavitation phenomena following pump

  20. Effect of Tempering and Baking on the Charpy Impact Energy of Hydrogen-Charged 4340 Steel

    Science.gov (United States)

    Mori, K.; Lee, E. W.; Frazier, W. E.; Niji, K.; Battel, G.; Tran, A.; Iriarte, E.; Perez, O.; Ruiz, H.; Choi, T.; Stoyanov, P.; Ogren, J.; Alrashaid, J.; Es-Said, O. S.

    2015-01-01

    Tempered AISI 4340 steel was hydrogen charged and tested for impact energy. It was found that samples tempered above 468 °C (875 °F) and subjected to hydrogen charging exhibited lower impact energy values when compared to uncharged samples. No significant difference between charged and uncharged samples tempered below 468 °C (875 °F) was observed. Neither exposure nor bake time had any significant effect on impact energy within the tested ranges.

  1. Effect of the surface charge discretization on electric double layers. A Monte Carlo simulation study

    OpenAIRE

    Madurga Díez, Sergio; Martín-Molina, Alberto; Vilaseca i Font, Eudald; Mas i Pujadas, Francesc; Quesada-Pérez, Manuel

    2007-01-01

    The structure of the electric double layer in contact with discrete and continuously charged planar surfaces is studied within the framework of the primitive model through Monte Carlo simulations. Three different discretization models are considered together with the case of uniform distribution. The effect of discreteness is analyzed in terms of charge density profiles. For point surface groups,a complete equivalence with the situation of uniformly distributed charge is found if profiles are...

  2. The effects of ion adsorption on the potential of zero charge and the differential capacitance of charged aqueous interfaces

    Science.gov (United States)

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

    2018-02-01

    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.

  3. Effects of emotionally charged auditory stimulation on gait performance in the elderly: a preliminary study.

    Science.gov (United States)

    Rizzo, John-Ross; Raghavan, Preeti; McCrery, J R; Oh-Park, Mooyeon; Verghese, Joe

    2015-04-01

    To evaluate the effect of a novel divided attention task-walking under auditory constraints-on gait performance in older adults and to determine whether this effect was moderated by cognitive status. Validation cohort. General community. Ambulatory older adults without dementia (N=104). Not applicable. In this pilot study, we evaluated walking under auditory constraints in 104 older adults who completed 3 pairs of walking trials on a gait mat under 1 of 3 randomly assigned conditions: 1 pair without auditory stimulation and 2 pairs with emotionally charged auditory stimulation with happy or sad sounds. The mean age of subjects was 80.6±4.9 years, and 63% (n=66) were women. The mean velocity during normal walking was 97.9±20.6cm/s, and the mean cadence was 105.1±9.9 steps/min. The effect of walking under auditory constraints on gait characteristics was analyzed using a 2-factorial analysis of variance with a 1-between factor (cognitively intact and minimal cognitive impairment groups) and a 1-within factor (type of auditory stimuli). In both happy and sad auditory stimulation trials, cognitively intact older adults (n=96) showed an average increase of 2.68cm/s in gait velocity (F1.86,191.71=3.99; P=.02) and an average increase of 2.41 steps/min in cadence (F1.75,180.42=10.12; Pactivities of daily living accounted for these differences. Our results provide preliminary evidence of the differentiating effect of emotionally charged auditory stimuli on gait performance in older individuals with minimal cognitive impairment compared with those without minimal cognitive impairment. A divided attention task using emotionally charged auditory stimuli might be able to elicit compensatory improvement in gait performance in cognitively intact older individuals, but lead to decompensation in those with minimal cognitive impairment. Further investigation is needed to compare gait performance under this task to gait on other dual-task paradigms and to separately examine the

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

    Directory of Open Access Journals (Sweden)

    Jinxiang Xi

    2014-01-01

    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.

  5. An analytical charge-based drain current model for nano-scale In0.52Al0.48As–In0.53Ga0.47 as a separated double-gate HEMT

    International Nuclear Information System (INIS)

    Rathi, Servin; Gupta, Mridula; Gupta, R S; Jogi, Jyotika

    2010-01-01

    In this paper, a two-dimensional electron gas (2DEG) charge-control model for carrier density in the channel is developed for a separated double-gate high-electron-mobility transistor. The model is extended to calculate I d –V g characteristics of the device. The drain current model uses a polynomial dependence of sheet carrier concentration on the position of a quasi-Fermi energy level to predict the modulation of back carrier concentration due to a front gate bias. The characteristics are investigated for various channel thicknesses and delta doping concentrations in order to study the effect of the back gate on the overall device performance. The analytical results so obtained are verified by comparing them with simulated and experimental results. A good agreement between the results is obtained, thus validating the model

  6. Trajectory effects in multiply charged ion-surface interactions

    International Nuclear Information System (INIS)

    Lebius, H.; Huang, W.; Schuch, R.

    1999-01-01

    Ar ions of 4.3 keV q in were scattered at large angles (θ=75 degree sign ) from a clean oriented surface. By selecting Ar projectiles having a large ionization potential and by using a large scattering angle only ions scattered at the first atomic layer of the surface were detected. Scattered ion energy spectra show peaks of single scattering and double scattering of the Ar projectile ions from one or two surface Au atoms, and the distribution attributed to double collisions splits into two peaks when the scattering plane coincides with a crystallographic plane. Simulations with a MARLOWE code allowed for interpretation of the structure in the double collision peak by in-plane and zig-zag double collisions. Differences in the relative peak heights between the experiment and a MARLOWE simulation were partly explained by different neutralization probabilities with varying trajectories. Yield changes with increasing charge states show interesting possibilities for future experiments with highly charged ions

  7. Space charge effects and coherent stability limits in barrier buckets

    Directory of Open Access Journals (Sweden)

    Oliver Boine-Frankenheim

    2003-03-01

    Full Text Available A large-scale Vlasov simulation study of the microwave instability below transition energy in a beam confined between two barrier pulses is performed. Starting from a matched distribution function for the confined ion beam including the space charge impedance the stability threshold in the longitudinal impedance plane is obtained. A simple stability criterium is found to be in good agreement with the simulation results.

  8. Space-charge effects in vacuum-deposited polyimide layer

    Czech Academy of Sciences Publication Activity Database

    Zhivkov, I.; Strijkova, V.; Spassova, E.; Danev, G.; Nešpůrek, Stanislav; Iwamoto, M.

    2005-01-01

    Roč. 7, č. 1 (2005), s. 245-248 ISSN 1454-4164 R&D Projects: GA MŠk ME 558 Grant - others:Ministry of Education and Science(BG) X-1322 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyimide * electrical conductivity * space-charge spectroscopy Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.138, year: 2005

  9. Space-charge effects in Penning ion traps

    Czech Academy of Sciences Publication Activity Database

    Porobic, T.; Beck, M.; Breitenfeldt, M.; Couratin, C.; Finlay, P.; Knecht, A.; Fabian, X.; Friedag, P.; Flechard, X.; Lienard, E.; Ban, G.; Zákoucký, Dalibor; Soti, G.; Van Gorp, S.; Weinheimer, C.; Wursten, E.; Severijns, N.

    2015-01-01

    Roč. 785, JUN (2015), s. 153-162 ISSN 0168-9002 R&D Projects: GA MŠk LA08015; GA MŠk(CZ) LG13031 Institutional support: RVO:61389005 Keywords : Penning trap * space-charge * magnetron motion * ion trapping * buffer gas cooling * ion cyclotron resonance Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.200, year: 2015

  10. Nonuniform charging effects on ion drag force in drifting dusty plasmas

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  11. Plasma effect on tunnelling, charge transfer and transient quasimolecular states

    International Nuclear Information System (INIS)

    Fisher, D V

    2003-01-01

    The influence of a dense plasma environment on electron tunnelling between two ion potential wells in collectivized states and in charge-transfer collisions is studied. We show that the tunnelling probabilities in dilute plasma (in a close ion-ion collision) and in dense plasma differ strongly. The difference is due to the mixing between Stark components of donor-ion energy levels, caused by the field of spectator ions in a dense plasma. The mixing is determined by an angle α between the nearest-neighbour ion field and the total electric field acting on the donor ion. In close ion-ion binary collisions the mixing may be considered weak. However, for most plasma ions charge transfer, electron state collectivization and transient quasimolecule formation are strongly affected by the field of spectator ions. We derive approximate analytical expressions for the distribution function of α in an ideal plasma and perform molecular dynamics simulations to find the distribution function of α in both ideal and nonideal plasmas. Both α-dependent and average mixing coefficients are determined. We have found that the mixing is strong, even in ideal plasmas, and increases further with an increase in plasma nonideality. It is shown that there is no resonant charge transfer in dense plasmas. The applicability of a transient 'dicenter' quasimolecule model for dense plasmas is discussed

  12. Effect of volume and surface charges on discharge structure of glow dielectric barrier discharge

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Shao-Wei; He, Feng; Wang, Yu; Li, Lulu; Ouyang, Ji-Ting [School of Physics, Beijing Institute of Technology, Beijing 100081 (China)

    2013-08-15

    The effect of volume and surface charges on the structure of glow dielectric barrier discharge (DBD) has been investigated numerically by using two-dimensional (2D) fluid modeling. The local increase of volume or surface charges induces a kind of activation-inhibition effect, which enhances the local volume discharge and inhibits the discharge in neighborhoods, resulting in non-uniform discharge. The activation-inhibition effect due to the non-uniform volume and/or surface charges depends on the non-uniformity itself and the applied voltage. The activation-inhibition of non-uniform charges has different effects on the volume charges and the accumulated surface charges. The distribution of remaining free charges (seed electrons) in volume at the beginning of voltage pulse plays a key role for the glow DBD structure, resulting in a patterned DBD, when the seed electrons are non-uniform at higher frequency and moderate voltage or uniform DBD, when the seed electrons are uniform at lower frequency or high voltage. The distribution of surface charges is not the determining factor but a result of the formed DBD structure.

  13. 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.

    2005-01-01

    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

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

    DEFF Research Database (Denmark)

    Benavente, Juana; Jonsson, Gunnar Eigil

    2002-01-01

    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 dep...

  15. Environmental Effects of a Kilometre Charge in Road Transport: an Investigation for the Netherlands

    NARCIS (Netherlands)

    Ubbels, B.J.; Rietveld, P.; Peeters, P.

    2002-01-01

    This study discusses the potential environmental effects of a kilometre charge for car traffic in the Netherlands. This kilometre charge would replace the existing taxes on new cars and on car ownership. It would lead to a substantial increase in the variable costs of car use. It may lead to a

  16. Many-body correlation effects in the spatially separated electron and hole layers in the coupled quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Babichenko, V.S. [RRC Kurchatov Institute, Kurchatov Sq., 1, 123182 Moscow (Russian Federation); Polishchuk, I.Ya., E-mail: iyppolishchuk@gmail.com [RRC Kurchatov Institute, Kurchatov Sq., 1, 123182 Moscow (Russian Federation); Moscow Institute of Physics and Technology, 141700, 9, Institutskii per., Dolgoprudny, Moscow Region (Russian Federation)

    2014-11-15

    The many-body correlation effects in the spatially separated electron and hole layers in the coupled quantum wells are investigated. A special case of the many-component electron–hole system is considered. It is shown that if the hole mass is much greater than the electron mass, the negative correlation energy is mainly determined by the holes. The ground state of the system is found to be the 2D electron–hole liquid with the energy smaller than the exciton phase. It is shown that the system decays into the spatially separated neutral electron–hole drops if the initially created charge density in the layers is smaller than the certain critical value n{sub eq}.

  17. Reduced graphene oxide wrapped Bi{sub 2}WO{sub 6} hybrid with ultrafast charge separation and improved photoelectrocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Huan [School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300130, PR China (China); Liang, Yinghua, E-mail: liangyh@ncst.edu.cn [School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300130, PR China (China); College of Chemical Engineering, North China University of Science and Technology, Tangshan 063009, PR China (China); Liu, Li; Hu, Jinshan [College of Chemical Engineering, North China University of Science and Technology, Tangshan 063009, PR China (China); Cui, Wenquan, E-mail: wkcui@163.com [College of Chemical Engineering, North China University of Science and Technology, Tangshan 063009, PR China (China)

    2017-01-15

    Highlights: • The rGO wrapped Bi{sub 2}WO{sub 6} photoelectrode was successfully synthesized. • The Bi{sub 2}WO{sub 6}@rGOhighlyincreasedthechargeseparationefficiency. • The photoelectrode exhibited enhanced photoelectrocatalytic degradation for RhB. - Abstract: A reduced graphene oxide (rGO) wrapped Bi{sub 2}WO{sub 6} (Bi{sub 2}WO{sub 6}@rGO) hybrid as photoelectrode for enhanced photoelectrocatalytic (PEC) degradation of organic pollutants is reported, which exhibited excellent charge separation and photoconversion efficiency. The core@shell structured Bi{sub 2}WO{sub 6}@rGO photoelectrode yielded a pronounced 1.56-fold and 23.8-fold photocurrent density at 1.0 V vs. saturated calomel electrode (SCE), than that of loading structured Bi{sub 2}WO{sub 6}-rGO and pure Bi{sub 2}WO{sub 6}. The Bi{sub 2}WO{sub 6}@rGO hybrid exhibited enhanced photoelectrocatalytic efficiency for degradation of Rhodamine B (RhB), which was 43.0% and 65.6% higher than that of photocatalytic (PC) and electrocatalytic (EC) processes, respectively. The enhancement in PEC degradation of RhB benefited from: (1) a strong interaction and a wide range of conjugation were formed in the core@shell system; (2) a 0.26 V of flat band potential was negatively shifted in case of Bi{sub 2}WO{sub 6}@rGO composite; (3) the photogenerated electrons and holes could be spatially separated by external electric potentials.

  18. Charge Dependence and Electric Quadrupole Effects on Single-Nucleon Removal in Relativistic and Intermediate Energy Nuclear Collisions

    Science.gov (United States)

    Norbury, John W.

    1992-01-01

    Single nucleon removal in relativistic and intermediate energy nucleus-nucleus collisions is studied using a generalization of Weizsacker-Williams theory that treats each electromagnetic multipole separately. Calculations are presented for electric dipole and quadrupole excitations and incorporate a realistic minimum impact parameter, Coulomb recoil corrections, and the uncertainties in the input photonuclear data. Discrepancies are discussed. The maximum quadrupole effect to be observed in future experiments is estimated and also an analysis of the charge dependence of the electromagnetic cross sections down to energies as low as 100 MeV/nucleon is made.

  19. Effect of paraelectrode processes on contraction of space charge in periodic-pulse lasers

    Science.gov (United States)

    Arytyunyan, R. V.; Baranov, V. Yu.; Borisov, V. M.; Vinokhodov, A. Yu.; Kiryukhin, Yu. B.

    1986-05-01

    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.

  20. Enhanced sunlight-driven photocatalytic performance of Bi-doped CdMoO4 benefited from efficient separation of photogenerated charge pairs

    Science.gov (United States)

    Huang, Jiao; Liu, Huanhuan; Zhong, Junbo; Yang, Qi; Chen, Jiufu; Li, Jianzhang; Ma, Dongmei; duan, Ran

    2018-06-01

    In this paper, to further boost the photocatalytic performance of CdMoO4, Bi3+ was successfully doped into CdMoO4 by a facile microwave hydrothermal method. The Bi-doped CdMoO4 photocatalysts prepared were characterized by Brunauer-Emmett-Teller (BET) method, X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), electron spin-resonance (ESR) and surface photovoltage spectroscopy (SPS). The results exhibit that doping Bi3+ into CdMoO4 remarkably boosts the separation rate of photoinduced charge pairs and the specific surface area, decrease the crystal size, narrows the band gap of the CdMoO4 and induces the binding energy shift of Cd, all these advantageous factors result in the promoted photocatalytic performance of CdMoO4. Using rhodamine B (RhB) as model toxic pollutant, the photocatalytic activities of the photocatalysts were evaluated under a 500 W Xe lamp irradiation. When the molar ratio of Bi/Cd is 0.2%, Bi-CdMoO4 prepared displays the best photocatalytic performance, the photocatalytic performance of the 0.2% sample is more than twice of that of the reference CdMoO4.

  1. Antiferroelectric Nature of CH3NH3PbI3-xClx Perovskite and Its Implication for Charge Separation in Perovskite Solar Cells

    Science.gov (United States)

    Sewvandi, Galhenage A.; Kodera, Kei; Ma, Hao; Nakanishi, Shunsuke; Feng, Qi

    2016-07-01

    Perovskite solar cells (PSCs) have been attracted scientific interest due to high performance. Some researchers have suggested anomalous behavior of PSCs to the polarizations due to the ion migration or ferroelectric behavior. Experimental results and theoretical calculations have suggested the possibility of ferroelectricity in organic-inorganic perovskite. However, still no studies have been concretely discarded the ferroelectric nature of perovskite absorbers in PSCs. Hysteresis of P-E (polarization-electric field) loops is an important evidence to confirm the ferroelectricity. In this study, P-E loop measurements, in-depth structural study, analyses of dielectric behavior and the phase transitions of CH3NH3PbI3-xClx perovskite were carried out and investigated. The results suggest that CH3NH3PbI3-xClx perovskite is in an antiferroelectric phase at room temperature. The antiferroelectric phase can be switched to ferroelectric phase by the poling treatment and exhibits ferroelectric-like hysteresis P-E loops and dielectric behavior around room temperature; namely, the perovskite can generate a ferroelectric polarization under PSCs operating conditions. Furthermore, we also discuss the implications of ferroelectric polarization on PSCs charge separation.

  2. Large-Scale Quantum Many-Body Perturbation on Spin and Charge Separation in the Excited States of the Synthesized Donor-Acceptor Hybrid PBI-Macrocycle Complex.

    Science.gov (United States)

    Ziaei, Vafa; Bredow, Thomas

    2017-03-17

    The reliable calculation of the excited states of charge-transfer (CT) compounds poses a major challenge to the ab initio community because the frequently employed method, time-dependent density functional theory (TD-DFT), massively relies on the underlying density functional, resulting in heavily Hartree-Fock (HF) exchange-dependent excited-state energies. By applying the highly sophisticated many-body perturbation approach, we address the encountered unreliabilities and inconsistencies of not optimally tuned (standard) TD-DFT regarding photo-excited CT phenomena, and present results concerning accurate vertical transition energies and the correct energetic ordering of the CT and the first visible singlet state of a recently synthesized thermodynamically stable large hybrid perylene bisimide-macrocycle complex. This is a large-scale application of the quantum many-body perturbation approach to a chemically relevant CT system, demonstrating the system-size independence of the quality of the many-body-based excitation energies. Furthermore, an optimal tuning of the ωB97X hybrid functional can well reproduce the many-body results, making TD-DFT a suitable choice but at the expense of introducing a range-separation parameter, which needs to be optimally tuned. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    CERN Document Server

    Mandalia, Jesal Paresh

    2017-01-01

    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.

  4. A Cost-Effective Electric Vehicle Charging Method Designed For Residential Homes with Renewable Energy

    Science.gov (United States)

    Lie, T. T.; Liang, Xiuli; Haque, M. H.

    2015-03-01

    Most of the electrical infrastructure in use around the world today is decades old, and may be illsuited to widespread proliferation of personal Electric Vehicles (EVs) whose charging requirements will place increasing strain on grid demand. In order to reduce the pressure on the grid and taking benefits of off peak charging, this paper presents a smart and cost effective EV charging methodology for residential homes equipped with renewable energy resources such as Photovoltaic (PV) panels and battery. The proposed method ensures slower battery degradation and prevents overcharging. The performance of the proposed algorithm is verified by conducting simulation studies utilizing running data of Nissan Altra. From the simulation study results, the algorithm is shown to be effective and feasible which minimizes not only the charging cost but also can shift the charging time from peak value to off-peak time.

  5. Effect of the space charge layer on pre-transition corrosion rate of Zr alloys

    International Nuclear Information System (INIS)

    Nanikawa, S.; Etoh, Y.

    1998-01-01

    The pre- and post-transition oxide films formed in steam at 673 K were investigated by an AC impedance method. The results showed that the space charge layer was present in the pre-transition oxide film and it was absent in the post-transition oxide film. The oxidation kinetics was simulated by oxygen diffusion in the space charge layer. Cubic or one-fourth power law was explained by the effect of the space charge layer. Supposing that the space charge layer formed the potential difference through the oxide film by 0.7 V, calculated oxidation kinetics agreed with the experimental one before transition. This potential difference corresponded to the measured value by AC impedance method within the experimental error. Shadow effect could be explained by this simulation supposing the disappearance of the space charge layer due to the formation of a negative electric field by β-rays. (author)

  6. Separate effects tests to determine the effective thermal conductivity in the PBMR HTTU test facility

    Energy Technology Data Exchange (ETDEWEB)

    Rousseau, P.G., E-mail: pgr@mtechindustrial.com [School of Mechanical and Nuclear Engineering, North-West University, Private Bag X6001, Potchefstroom 2520 (South Africa); Toit, C.G. du; Antwerpen, W. van [School of Mechanical and Nuclear Engineering, North-West University, Private Bag X6001, Potchefstroom 2520 (South Africa); Antwerpen, H.J. van [M-Tech Industrial (Pty) Ltd., PO Box 19855, Noordbrug 2522 (South Africa)

    2014-05-01

    Thermal-fluid simulations are used extensively to predict the maximum fuel temperatures, flows, pressure drops and thermal capacitance of pebble bed gas cooled reactors in support of the reactor safety case. The PBMR company developed the HTTU non-nuclear test facility in cooperation with M-Tech Industrial (Pty) Ltd. and the North-West University in South Africa to conduct comprehensive separate effects tests as well as integrated effects tests to study the different thermal-fluid phenomena. This paper describes the separate effects tests that were conducted to determine the effective thermal conductivity through the pebble bed under near-vacuum conditions and temperatures up to 1200 °C. It also presents the measured temperature distributions and the methodology applied in the data analysis to derive the resultant values of effective thermal conductivity and its associated uncertainty.

  7. Separate effects tests to determine the effective thermal conductivity in the PBMR HTTU test facility

    International Nuclear Information System (INIS)

    Rousseau, P.G.; Toit, C.G. du; Antwerpen, W. van; Antwerpen, H.J. van

    2014-01-01

    Thermal-fluid simulations are used extensively to predict the maximum fuel temperatures, flows, pressure drops and thermal capacitance of pebble bed gas cooled reactors in support of the reactor safety case. The PBMR company developed the HTTU non-nuclear test facility in cooperation with M-Tech Industrial (Pty) Ltd. and the North-West University in South Africa to conduct comprehensive separate effects tests as well as integrated effects tests to study the different thermal-fluid phenomena. This paper describes the separate effects tests that were conducted to determine the effective thermal conductivity through the pebble bed under near-vacuum conditions and temperatures up to 1200 °C. It also presents the measured temperature distributions and the methodology applied in the data analysis to derive the resultant values of effective thermal conductivity and its associated uncertainty

  8. Coherent charge fluctuations in Josephson junctions and the oscillations of the effective capacitance

    International Nuclear Information System (INIS)

    Krive, I.V.; Rozhavsky, A.S.

    1990-07-01

    We predict novel voltage oscillations of the effective capacitance of small Josephson junctions. This macroscopic effect involves coherent charge fluctuations with charge 2e, leading to a period of oscillations, V c = 2e/C, where C is the junction capacitance. The amplitude of the effect decreases with temperature as exp(-π 2 T/ε c ), where ε c = (2e) 2 /C. (author). 6 refs

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

    OpenAIRE

    Nouchi, Ryo; Tanigaki, Katsumi

    2010-01-01

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

  10. History of the Shaped Charge Effect: The First 100 Years

    Science.gov (United States)

    1990-03-22

    patent, wave shapers, follow-through, U.S. 1949 39 6.5-in. ATAR HEAT rocket, U.S. NOTS, 1950 (schematic) 40 Test of 15-in. long standoff shaped charge...Swiss chemist Frederick Schoenbein in 1845, and nitroglycerin, derived by Ascanio Sobrero, professor of Chemistry at the University of Turin, Italy, in...totally new warhead and fuze system and delivery of the first 1000 rounds to Korea in less than 20 days! The 6.5-Inch ATAR (Code Name "RAM") The 6.5

  11. Dynamical image-charge effect in molecular tunnel junctions

    DEFF Research Database (Denmark)

    Jin, Chengjun; Thygesen, Kristian Sommer

    2014-01-01

    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....

  12. Fractional charges

    International Nuclear Information System (INIS)

    Saminadayar, L.

    2001-01-01

    20 years ago fractional charges were imagined to explain values of conductivity in some materials. Recent experiments have proved the existence of charges whose value is the third of the electron charge. This article presents the experimental facts that have led theorists to predict the existence of fractional charges from the motion of quasi-particles in a linear chain of poly-acetylene to the quantum Hall effect. According to the latest theories, fractional charges are neither bosons nor fermions but anyons, they are submitted to an exclusive principle that is less stringent than that for fermions. (A.C.)

  13. High-order space charge effects using automatic differentiation

    International Nuclear Information System (INIS)

    Reusch, Michael F.; Bruhwiler, David L.

    1997-01-01

    The Northrop Grumman Topkark code has been upgraded to Fortran 90, making use of operator overloading, so the same code can be used to either track an array of particles or construct a Taylor map representation of the accelerator lattice. We review beam optics and beam dynamics simulations conducted with TOPKARK in the past and we present a new method for modeling space charge forces to high-order with automatic differentiation. This method generates an accurate, high-order, 6-D Taylor map of the phase space variable trajectories for a bunched, high-current beam. The spatial distribution is modeled as the product of a Taylor Series times a Gaussian. The variables in the argument of the Gaussian are normalized to the respective second moments of the distribution. This form allows for accurate representation of a wide range of realistic distributions, including any asymmetries, and allows for rapid calculation of the space charge fields with free space boundary conditions. An example problem is presented to illustrate our approach

  14. High-order space charge effects using automatic differentiation

    International Nuclear Information System (INIS)

    Reusch, M.F.; Bruhwiler, D.L.; Computer Accelerator Physics Conference Williamsburg, Virginia 1996)

    1997-01-01

    The Northrop Grumman Topkark code has been upgraded to Fortran 90, making use of operator overloading, so the same code can be used to either track an array of particles or construct a Taylor map representation of the accelerator lattice. We review beam optics and beam dynamics simulations conducted with TOPKARK in the past and we present a new method for modeling space charge forces to high-order with automatic differentiation. This method generates an accurate, high-order, 6-D Taylor map of the phase space variable trajectories for a bunched, high-current beam. The spatial distribution is modeled as the product of a Taylor Series times a Gaussian. The variables in the argument of the Gaussian are normalized to the respective second moments of the distribution. This form allows for accurate representation of a wide range of realistic distributions, including any asymmetries, and allows for rapid calculation of the space charge fields with free space boundary conditions. An example problem is presented to illustrate our approach. copyright 1997 American Institute of Physics

  15. Radioactive isotope and isomer separation with using light induced drift effect

    International Nuclear Information System (INIS)

    Hradecny, C.; Slovak, J.; Tethal, T.; Ermolaev, I.M.; Shalagin, A.M.

    1991-01-01

    The isotope separation with using light induced drift (LID) is discussed. The basic theoretical characteristics of the method are deduced: separation simultaneously with an arbitrary high enrichment and without significant losses; separation productivity up to 100 μg/h. These characteristics are sufficient and very convenient for separation of expensive radioactive isotopes and isomers which are applied in medicine and science. The first experimental separation of the radioactive isotopes ( 22,24 Na) by using the LID effect is reported. 13 refs.; 5 figs

  16. The effects of electromagnetic space-charge fields in RF photocathode guns

    International Nuclear Information System (INIS)

    Park, C.S.; Hess, M.

    2010-01-01

    In high-brightness rf photocathode guns, the effects of space-charge are important for electron bunches with high bunch charge. In an effort to accurately simulate the effects of these space-charge fields without the presence of numerical grid dispersion, a Green's function based code called IRPSS (Indiana Rf Photocathode Source Simulator) was developed. In this paper, we show the results of numerical simulations of the Argonne Wakefield Accelerator photocathode gun using IRPSS, and compare them with the results of an electrostatic Green's function version of IRPSS.

  17. Electrostatic Screening and Charge Correlation Effects in Micellization of Ionic Surfactants

    KAUST Repository

    Jusufi, Arben; Hynninen, Antti-Pekka; Haataja, Mikko; Panagiotopoulos, Athanassios Z.

    2009-01-01

    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

  18. Genetic effects of charged particles. Proceedings of conference; Geneticheskoe dejstvie korpuskulyarnykh izluchenij. Trudy rabochego soveshchaniya

    Energy Technology Data Exchange (ETDEWEB)

    1990-07-01

    This volume contains the proceedings of the conference entitled Genetic Effects of Charged Particles held in Dubna, Ukrainian Soviet Socialist Republic June 1990. Selected presentations were abstracted and indexed for the database.

  19. Effect of membrane hydrophilization on ultrafiltration performance for biomolecules separation

    International Nuclear Information System (INIS)

    Susanto, H.; Roihatin, A.; Aryanti, N.; Anggoro, D.D.; Ulbricht, M.

    2012-01-01

    This paper compares the performance of different hydrophilization methods to prepare low fouling ultrafiltration (UF) membranes. The methods include post-modification with hydrophilic polymer and blending of hydrophilic agent during either conventional or reactive phase separation (PS). The post-modification was done by photograft copolymerization of water-soluble monomer, poly(ethylene glycol) methacrylate (PEGMA), onto a commercial polyethersulfone (PES) UF membrane. Hydrophilization via blend polymer membrane with hydrophilic additive was performed using non-solvent induced phase separation (NIPS). In reactive PS method, the cast membrane was UV-irradiated before coagulation. The resulting membrane characteristic, the performance and hydrophilization stability were systematically compared. The investigated membrane characteristics include surface hydrophilicity (by contact angle /CA/), surface chemistry (by FTIR spectroscopy), and surface morphology (by scanning electron microscopy). The membrane performance was examined by investigation of adsorptive fouling and ultrafiltration using solution of protein or polysaccharide or humic acid. The results suggest that all methods could increase the hydrophilicity of the membrane yielding less fouling. Post-modification decreased CA from 44.8 ± 4.2 o to 37.8 ± 4.2 o to 42.5 ± 4.3 o depending on the degree of grafting (DG). The hydrophilization via polymer blend decreased CA from from 65 deg. to 54 deg. for PEG concentration of 5%. Nevertheless, decreasing hydraulic permeability was observed after post-modification as well as during polymer blend modification. Stability examination showed that there was leaching out of modifier agent from the membrane matrix prepared via conventional PS after 10 days soaking in both water and NaOH. Reactive PS could increase the stability of the modifier agent in membrane matrix. Highlights: ► We compared different methods to prepare low fouling ultrafiltration (UF) membranes.

  20. Effect of membrane hydrophilization on ultrafiltration performance for biomolecules separation

    Energy Technology Data Exchange (ETDEWEB)

    Susanto, H., E-mail: heru.susanto@undip.ac.id [Department of Chemical Engineering, Universitas Diponegoro, Jl. Prof. Sudarto-Tembalang, Semarang (Indonesia); Roihatin, A.; Aryanti, N.; Anggoro, D.D. [Department of Chemical Engineering, Universitas Diponegoro, Jl. Prof. Sudarto-Tembalang, Semarang (Indonesia); Ulbricht, M. [Lehrstuhl fuer Technische Chemie, Universitaet Duisburg-Essen, Germany, Universitaetstr. 5, Essen (Germany)

    2012-10-01

    This paper compares the performance of different hydrophilization methods to prepare low fouling ultrafiltration (UF) membranes. The methods include post-modification with hydrophilic polymer and blending of hydrophilic agent during either conventional or reactive phase separation (PS). The post-modification was done by photograft copolymerization of water-soluble monomer, poly(ethylene glycol) methacrylate (PEGMA), onto a commercial polyethersulfone (PES) UF membrane. Hydrophilization via blend polymer membrane with hydrophilic additive was performed using non-solvent induced phase separation (NIPS). In reactive PS method, the cast membrane was UV-irradiated before coagulation. The resulting membrane characteristic, the performance and hydrophilization stability were systematically compared. The investigated membrane characteristics include surface hydrophilicity (by contact angle /CA/), surface chemistry (by FTIR spectroscopy), and surface morphology (by scanning electron microscopy). The membrane performance was examined by investigation of adsorptive fouling and ultrafiltration using solution of protein or polysaccharide or humic acid. The results suggest that all methods could increase the hydrophilicity of the membrane yielding less fouling. Post-modification decreased CA from 44.8 {+-} 4.2{sup o} to 37.8 {+-} 4.2{sup o} to 42.5 {+-} 4.3{sup o} depending on the degree of grafting (DG). The hydrophilization via polymer blend decreased CA from from 65 deg. to 54 deg. for PEG concentration of 5%. Nevertheless, decreasing hydraulic permeability was observed after post-modification as well as during polymer blend modification. Stability examination showed that there was leaching out of modifier agent from the membrane matrix prepared via conventional PS after 10 days soaking in both water and NaOH. Reactive PS could increase the stability of the modifier agent in membrane matrix. Highlights: Black-Right-Pointing-Pointer We compared different methods to prepare low

  1. Effect of the surface charge discretization on electric double layers: a Monte Carlo simulation study.

    Science.gov (United States)

    Madurga, Sergio; Martín-Molina, Alberto; Vilaseca, Eudald; Mas, Francesc; Quesada-Pérez, Manuel

    2007-06-21

    The structure of the electric double layer in contact with discrete and continuously charged planar surfaces is studied within the framework of the primitive model through Monte Carlo simulations. Three different discretization models are considered together with the case of uniform distribution. The effect of discreteness is analyzed in terms of charge density profiles. For point surface groups, a complete equivalence with the situation of uniformly distributed charge is found if profiles are exclusively analyzed as a function of the distance to the charged surface. However, some differences are observed moving parallel to the surface. Significant discrepancies with approaches that do not account for discreteness are reported if charge sites of finite size placed on the surface are considered.

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

    KAUST Repository

    Li, Sheng

    2011-12-01

    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.

  3. PSR experience with beam losses, instabilities and space charge effects

    International Nuclear Information System (INIS)

    Macek, R.J.

    1998-01-01

    Average current from the PSR has been limited to ∼70 μA at 20 Hz by beam losses of 0.4 to 0.5 μA which arise from two principal causes, production of H 0 excited states and stored-beam scattering in the stripper foil. To reduce beam losses, an upgrade from the two-step H 0 injection to direct H - injection is underway and will be completed in 1998. Peak intensity from the PSR is limited by a strong instability that available evidence indicates is the two-stream e-p instability. New evidence for the e-p hypothesis is presented. At operating intensities, the incoherent space charge tune shift depresses both horizontal and vertical tunes past the integer without additional beam loss although some intensity-dependent emittance growth is observed. copyright 1998 American Institute of Physics

  4. PSR experience with beam losses, instabilities and space charge effects

    International Nuclear Information System (INIS)

    Macek, Robert J.

    1998-01-01

    Average current from the PSR has been limited to ∼70 μA at 20 Hz by beam losses of 0.4 to 0.5 μA which arise from two principal causes, production of H 0 excited states and stored-beam scattering in the stripper foil. To reduce beam losses, an upgrade from the two-step H 0 injection to direct H - injection is underway and will be completed in 1998. Peak intensity from the PSR is limited by a strong instability that available evidence indicates is the two-stream e-p instability. New evidence for the e-p hypothesis is presented. At operating intensities, the incoherent space charge tune shift depresses both horizontal and vertical tunes past the integer without additional beam loss although some intensity-dependent emittance growth is observed

  5. Effect of the space-charge force on tracking at low energy

    International Nuclear Information System (INIS)

    Furman, M.A.

    1987-01-01

    The authors present tracking results for the SSC's Low Energy Booster at injection energy, including the effect of the space-charge force. The bunches are assumed to be gaussian with elliptical cross-section. Magnet errors and sextupoles are not included, but an RF cavity is. The authors compare the phase space with and without synchrotron oscillations, with and without space-charge. The effective emittance is not significantly altered. They also present results on tune shifts with amplitude

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

    Science.gov (United States)

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

    2013-08-01

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

  7. Moisture effect on the dielectric response and space charge behaviour of mineral oil impregnated paper insulation

    International Nuclear Information System (INIS)

    Hao Jian; Liao Ruijin; Chen, George

    2011-01-01

    Dielectric response and space charge behaviour of oil-paper insulation sample with different moisture contents were investigated using the frequency dielectric spectroscopy (FDS) and the pulsed electroacoustic (PEA) technique, respectively. The influence of moisture on the dielectric response and space charge behaviour of oil impregnated paper insulation was analysed. Results show that the moisture has great effect on the FDS and space charge behaviour of oil impregnated paper insulation. In the frequency range of 10 -2 ∼10 6 Hz, the conductivity and the capacitance of oil impregnated paper increases with its moisture content. The space charge distribution of oil-paper sample with lower and higher moisture contents is very different from each other. The higher the moisture concentration of the oil impregnated paper, the easier the negative charge penetration into the insulation paper. There is a significant amount of positive charge accumulated at the paper-paper interface near to the cathode for oilpaper sample with lower moisture content. However, the positive charge appears in the middle layer paper for oil-paper sample with higher moisture content. Due to the high conductivity, the charge trapped in the oil-paper sample with higher moisture content disappears much faster than that in the oil-paper sample with lower moisture content after removing the voltage.

  8. Stochastic charging of dust grains in planetary rings: Diffusion rates and their effects on Lorentz resonances

    Science.gov (United States)

    Schaffer, L.; Burns, J. A.

    1995-01-01

    Dust grains in planetary rings acquire stochastically fluctuating electric charges as they orbit through any corotating magnetospheric plasma. Here we investigate the nature of this stochastic charging and calculate its effect on the Lorentz resonance (LR). First we model grain charging as a Markov process, where the transition probabilities are identified as the ensemble-averaged charging fluxes due to plasma pickup and photoemission. We determine the distribution function P(t;N), giving the probability that a grain has N excess charges at time t. The autocorrelation function tau(sub q) for the strochastic charge process can be approximated by a Fokker-Planck treatment of the evolution equations for P(t; N). We calculate the mean square response to the stochastic fluctuations in the Lorentz force. We find that transport in phase space is very small compared to the resonant increase in amplitudes due to the mean charge, over the timescale that the oscillator is resonantly pumped up. Therefore the stochastic charge variations cannot break the resonant interaction; locally, the Lorentz resonance is a robust mechanism for the shaping of etheral dust ring systems. Slightly stronger bounds on plasma parameters are required when we consider the longer transit times between Lorentz resonances.

  9. Moisture effect on the dielectric response and space charge behaviour of mineral oil impregnated paper insulation

    Energy Technology Data Exchange (ETDEWEB)

    Hao Jian; Liao Ruijin [State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University (China); Chen, George, E-mail: jh210v@ecs.soton.ac.uk [School of Electronics and Computer Science, University of Southampton (United Kingdom)

    2011-08-12

    Dielectric response and space charge behaviour of oil-paper insulation sample with different moisture contents were investigated using the frequency dielectric spectroscopy (FDS) and the pulsed electroacoustic (PEA) technique, respectively. The influence of moisture on the dielectric response and space charge behaviour of oil impregnated paper insulation was analysed. Results show that the moisture has great effect on the FDS and space charge behaviour of oil impregnated paper insulation. In the frequency range of 10{sup -2}{approx}10{sup 6}Hz, the conductivity and the capacitance of oil impregnated paper increases with its moisture content. The space charge distribution of oil-paper sample with lower and higher moisture contents is very different from each other. The higher the moisture concentration of the oil impregnated paper, the easier the negative charge penetration into the insulation paper. There is a significant amount of positive charge accumulated at the paper-paper interface near to the cathode for oilpaper sample with lower moisture content. However, the positive charge appears in the middle layer paper for oil-paper sample with higher moisture content. Due to the high conductivity, the charge trapped in the oil-paper sample with higher moisture content disappears much faster than that in the oil-paper sample with lower moisture content after removing the voltage.

  10. A Monte Carlo modeling on charging effect for structures with arbitrary geometries

    Science.gov (United States)

    Li, C.; Mao, S. F.; Zou, Y. B.; Li, Yong Gang; Zhang, P.; Li, H. M.; Ding, Z. J.

    2018-04-01

    Insulating materials usually suffer charging effects when irradiated by charged particles. In this paper, we present a Monte Carlo study on the charging effect caused by electron beam irradiation for sample structures with any complex geometry. When transporting in an insulating solid, electrons encounter elastic and inelastic scattering events; the Mott cross section and a Lorentz-type dielectric function are respectively employed to describe such scatterings. In addition, the band gap and the electron–long optical phonon interaction are taken into account. The electronic excitation in inelastic scattering causes generation of electron–hole pairs; these negative and positive charges establish an inner electric field, which in turn induces the drift of charges to be trapped by impurities, defects, vacancies etc in the solid, where the distributions of trapping sites are assumed to have uniform density. Under charging conditions, the inner electric field distorts electron trajectories, and the surface electric potential dynamically alters secondary electron emission. We present, in this work, an iterative modeling method for a self-consistent calculation of electric potential; the method has advantages in treating any structure with arbitrary complex geometry, in comparison with the image charge method—which is limited to a quite simple boundary geometry. Our modeling is based on: the combination of the finite triangle mesh method for an arbitrary geometry construction; a self-consistent method for the spatial potential calculation; and a full dynamic description for the motion of deposited charges. Example calculations have been done to simulate secondary electron yield of SiO2 for a semi-infinite solid, the charging for a heterostructure of SiO2 film grown on an Au substrate, and SEM imaging of a SiO2 line structure with rough surfaces and SiO2 nanoparticles with irregular shapes. The simulations have explored interesting interlaced charge layer distribution

  11. The Effects of Parent-Adolescent Relationships and Parental Separation on Adolescent Well-Being.

    Science.gov (United States)

    Videon, Tami M.

    2002-01-01

    Data from the National Longitudinal Study of Adolescent Health were used to investigate the effects of parental separation on adolescent delinquency and depression. Parent-adolescent relationship prior to marital dissolution moderated the effects of parental separation on adolescent delinquency. Opposite-sex parents had a significant influence on…

  12. Charge independence and charge symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Miller, G A [Washington Univ., Seattle, WA (United States). Dept. of Physics; van Oers, W T.H. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Physics; [TRIUMF, Vancouver, BC (Canada)

    1994-09-01

    Charge independence and charge symmetry are approximate symmetries of nature, violated by the perturbing effects of the mass difference between up and down quarks and by electromagnetic interactions. The observations of the symmetry breaking effects in nuclear and particle physics and the implications of those effects are reviewed. (author). 145 refs., 3 tabs., 11 figs.

  13. Charge independence and charge symmetry

    International Nuclear Information System (INIS)

    Miller, G.A.

    1994-09-01

    Charge independence and charge symmetry are approximate symmetries of nature, violated by the perturbing effects of the mass difference between up and down quarks and by electromagnetic interactions. The observations of the symmetry breaking effects in nuclear and particle physics and the implications of those effects are reviewed. (author). 145 refs., 3 tabs., 11 figs

  14. Birth order effects on the separation process in young adults: an evolutionary and dynamic approach.

    Science.gov (United States)

    Ziv, Ido; Hermel, Orly

    2011-01-01

    The present study analyzes the differential contribution of a familial or social focus in imaginative ideation (the personal fable and imagined audience mental constructs) to the separation-individuation process of firstborn, middleborn, and lastborn children. A total of 160 young adults were divided into 3 groups by birth order. Participants' separation-individuation process was evaluated by the Psychological Separation Inventory, and results were cross-validated by the Pathology of Separation-Individuation Inventory. The Imaginative Ideation Inventory tested the relative dominance of the familial and social environments in participants' mental constructs. The findings showed that middleborn children had attained more advanced separation and were lower in family-focused ideation and higher in nonfamilial social ideation. However, the familial and not the social ideation explained the variance in the separation process in all the groups. The findings offer new insights into the effects of birth order on separation and individuation in adolescents and young adults.

  15. 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)

    2015-02-12

    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

  16. Effect of solvent on the charging mechanisms of poly(ethylene glycol) in droplets

    Science.gov (United States)

    Soltani, Sepideh; Oh, Myong In; Consta, Styliani

    2015-03-01

    We examine the effect of solvent on the charging mechanisms of a macromolecule in a droplet by using molecular dynamics simulations. The droplet contains excess charge that is carried by sodium ions. To investigate the principles of the charging mechanisms of a macromolecule in a droplet, we simulate aqueous and methanol droplets that contain a poly(ethylene glycol) (PEG) molecule. We find that the solvent plays a critical role in the charging mechanism and in the manner that the sodiated PEG emerges from a droplet. In the aqueous droplets, the sodiated PEG is released from the droplet while it is being charged at a droplet charge state below the Rayleigh limit. The charging of PEG occurs on the surface of the droplet. In contrast to the aqueous droplets, in the methanol droplet, the sodiated PEG resides in the interior of the droplet and it may become charged at any location in the droplet, interior or surface. The sodiated PEG emerges from the droplet by drying-out of the solvent. Even though these two mechanisms appear to be phenomenologically similar to the widely accepted ion-evaporation and charge-residue mechanisms, they have fundamental differences from those. An integral part of the mechanism that the macromolecular ions emerge from droplets is the droplet morphology. Droplet morphologies give rise to different solvation interactions between the solvent and the macromolecule. In the water-sodiated PEG system, we find the extrusion of the PEG morphology, while in methanol-sodiated droplet, we find the "pearl-on-the-necklace" morphology and the extrusion of the sodiated PEG in the last stage of the desolvation process. These findings provide insight into the mechanisms that macromolecules acquire their charge in droplets produced in electrospray ionization experiments.

  17. Effect of chromatographic separation on ASP system interface tension and the countermeasures

    Directory of Open Access Journals (Sweden)

    Jiawei REN

    2016-06-01

    Full Text Available Because of the existing chromatographic separation phenomenon, ASP flooding changes original nature of the system. Therefore, in laboratory ultra-low interfacial tension ASP system is preferred for sand packs flow experiment to research on the effect of chromatographic separation on ASP system interface tension. The two parameters of "breakthrough time" and "output difference" are used to describe the degree of chromatographic separation, and the produced fluid interfacial tensions at the outlet end at 120 min is measured. The research shows that there exists chromatographic separation between three chemicals of ASP system, with first polymer breakthrough and finally surfactant breakthrough; there is most serious chromatographic separation between surfactant and polymer, while minimum chromatographic separation between alkali and polymer; chromatographic separation makes ASP interfacial tension increase from 10-3 magnitude to 10-2 magnitude, affecting flooding effect of ASP system. Thus, reducing the loss of surfactant in the formation will be the main measure to reduce the degree of chromatographic separation. Using sophorolipid as sacrificial agent to replace part of the surfactant injected into formation before ASP system can effectively reduce the impact of chromatography separation and more effectively improve the ultimate recovery ratio.

  18. Effect of seeds of heavy charged particles of galactic cosmic radiation

    International Nuclear Information System (INIS)

    Maksimova, Y.N.

    1985-01-01

    The experiments were carried out on Lactuca sativa seeds exposed for 20, 66, 123 and 308 days in a biostack also containing physical detectors of heavy charged particles. The yield of aberrant cells and its dependence on the exposure time and the site where particles hit the object were measured. The cytogenetic examination demonstrated a significant difference between the seeds that were or were not hit by heavy charged particles. A significant contribution of galactic cosmic radiation to the radiobiological effect is indicated. The yield of aberrant cells as a function of the localization of heavy charged particles in the seed is established. The most sensitive target is the root meristem

  19. Modeling of capacitor charging dynamics in an energy harvesting system considering accurate electromechanical coupling effects

    Science.gov (United States)

    Bagheri, Shahriar; Wu, Nan; Filizadeh, Shaahin

    2018-06-01

    This paper presents an iterative numerical method that accurately models an energy harvesting system charging a capacitor with piezoelectric patches. The constitutive relations of piezoelectric materials connected with an external charging circuit with a diode bridge and capacitors lead to the electromechanical coupling effect and the difficulty of deriving accurate transient mechanical response, as well as the charging progress. The proposed model is built upon the Euler-Bernoulli beam theory and takes into account the electromechanical coupling effects as well as the dynamic process of charging an external storage capacitor. The model is validated through experimental tests on a cantilever beam coated with piezoelectric patches. Several parametric studies are performed and the functionality of the model is verified. The efficiency of power harvesting system can be predicted and tuned considering variations in different design parameters. Such a model can be utilized to design robust and optimal energy harvesting system.

  20. The effect of interface trapped charges in DMG-S-SOI MOSFET: a perspective study

    International Nuclear Information System (INIS)

    Mohapatra, S K; Pradhan, K P; Sahu, P K; Pati, G S; Kumar, M R

    2014-01-01

    In this paper, the existing two-dimensional (2D) threshold voltage model for a dual material gate fully depleted strained silicon on insulator (DMG-FD-S-SOI) metal-oxide-semiconductor field effect transistor (MOSFET) is modified by considering the interface trapped charge effects. The interface trapped charge is a common phenomenon, and this charge cannot be neglected in nanoscale devices. For finding out the surface potential, parabolic approximation has been utilized and the virtual cathode potential method is used to formulate the threshold voltage. The developed threshold voltage model incorporates both positive as well as negative interface charges. Finally, validity of the presented model is verified with 2D device simulator Sentaurus™. (paper)

  1. The effect of interface trapped charges in DMG-S-SOI MOSFET: a perspective study

    Science.gov (United States)

    Mohapatra, S. K.; Pradhan, K. P.; Sahu, P. K.; Pati, G. S.; Kumar, M. R.

    2014-12-01

    In this paper, the existing two-dimensional (2D) threshold voltage model for a dual material gate fully depleted strained silicon on insulator (DMG-FD-S-SOI) metal-oxide-semiconductor field effect transistor (MOSFET) is modified by considering the interface trapped charge effects. The interface trapped charge is a common phenomenon, and this charge cannot be neglected in nanoscale devices. For finding out the surface potential, parabolic approximation has been utilized and the virtual cathode potential method is used to formulate the threshold voltage. The developed threshold voltage model incorporates both positive as well as negative interface charges. Finally, validity of the presented model is verified with 2D device simulator Sentaurus™.

  2. Effective electrostatic interactions among charged thermo-responsive microgels immersed in a simple electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    González-Mozuelos, P. [Departamento de Física, Cinvestav del I. P. N., Av. Instituto Politécnico Nacional 2508, Mexico, Distrito Federal, C. P. 07360 (Mexico)

    2016-02-07

    This work explores the nature and thermodynamic behavior of the effective electrostatic interactions among charged microgels immersed in a simple electrolyte, taking special interest in the effects due to the thermally induced variation of the microgel size while the remaining parameters (microgel charge and concentration, plus the amount of added salt) are kept constant. To this end, the rigorous approach obtained from applying the precise methodology of the dressed ion theory to the proper definition of the effective direct correlation functions, which emerge from tracing-out the degrees of freedom of the microscopic ions, is employed to provide an exact description of the parameters characterizing such interactions: screening length, effective permittivity, and renormalized charges. A model solution with three components is assumed: large permeable anionic spheres for the microgels, plus small charged hard spheres of equal size for the monovalent cations and anions. The two-body correlations among the components of this model suspension, used as the input for the determination of the effective interaction parameters, are here calculated by using the hyper-netted chain approximation. It is then found that at finite microgel concentrations the values of these parameters change as the microgel size increases, even though the ionic strength of the supporting electrolyte and the bare charge of the microgels remain fixed during this process. The variation of the screening length, as well as that of the effective permittivity, is rather small, but still interesting in view of the fact that the corresponding Debye length stays constant. The renormalized charges, in contrast, increase markedly as the microgels swell. The ratio of the renormalized charge to the corresponding analytic result obtained in the context of an extended linear response theory allows us to introduce an effective charge that accounts for the non-linear effects induced by the short

  3. Separation of source and propagation effects at regional distances

    Energy Technology Data Exchange (ETDEWEB)

    Goldstein, P.; Jarpe, S.; Mayeda, K. [Lawrence Livermore National Lab., CA (United States)] [and others

    1994-12-31

    Improved estimates of the contributions of source and propagation effects to regional seismic signals are needed to explain the performance of existing discriminants and to help develop more robust methods for identifying underground explosions. In this paper, we use close-in, local, and regional estimates of explosion source time functions to remove source effects from regional recordings of the Non-Proliferation Experiment (NPE), a one kiloton chemical explosion in N-tunnel at Rainier Mesa on the Nevada Test Site, and nearby nuclear explosions and earthquakes. Using source corrected regional waveforms, we find that regional Pg and Lg spectra of shallow explosions have significant low frequency ({approximately}1Hz) enhancements when compared to normal depth earthquakes. Data and simulations suggest that such enhancements are most sensitive to source depth, but may also be a function of mechanism, source receiver distance, and regional structure.

  4. Separating discriminative and function-altering effects of verbal stimuli

    OpenAIRE

    Schlinger, Henry D.

    1993-01-01

    Ever since Skinner's first discussion of rule-governed behavior, behavior analysts have continued to define rules, either explicitly or implicitly, as verbal discriminative stimuli. Consequently, it is not difficult to find, in the literature on rule-governed behavior, references to stimulus control, antecedent control, or to rules occasioning behavior. However, some verbal stimuli have effects on behavior that are not easily described as discriminative. Such stimuli don't evoke behavior as d...

  5. Radiation effects on phase separation and viscosity of glasses

    International Nuclear Information System (INIS)

    Biron, I.; Barbu, A.

    1987-06-01

    The effect of electron irradiations on the stability of B 2 O 3P bO glasses is studied by transmission electron microscopy. Rapid coagulation of pure lead particles is observed. By using the Smoluchosky's coagulation theory, it is shown that the viscosity of B 2 O 3 is drastically reduced by several orders of magnitude under irradiation. The electron excitations are shown to play the dominant role in this phenomena

  6. The effect of temperature on guiding of slow highly charged ions through a mesoscopic glass capillary

    International Nuclear Information System (INIS)

    Bereczky, R J; Tökési, K; Kowarik, G; Ladinig, F; Schrempf, D; Aumayr, F

    2012-01-01

    We present first temperature dependent transmission measurements of slow highly charged ions through a single, straight Duran glass capillary with a high aspect ratio. By changing the temperature of the glass capillary the electrical conductivity of the Duran can be varied by several orders of magnitude. This held the promise to investigate the effect of conductivity on particle transport (build-up and removal of charge patches) through capillaries in more details.

  7. Statistical assessment of coal charge effect on metallurgical coke quality

    Directory of Open Access Journals (Sweden)

    Pavlína Pustějovská

    2016-06-01

    Full Text Available The paper studies coke quality. Blast furnace technique has been interested in iron ore charge; meanwhile coke was not studied because, in previous conditions, it seemed to be good enough. Nowadays, requirements for blast furnace coke has risen, especially, requirements for coke reactivity. The level of reactivity parameter is determined primarily by the composition and properties of coal mixtures for coking. The paper deals with a statistical analysis of the tightness and characteristics of the relationship between selected properties of coal mixture and coke reactivity. Software Statgraphic using both simple linear regression and multiple linear regressions was used for the calculations. Obtained regression equations provide a statistically significant prediction of the reactivity of coke, or its strength after reduction of CO2, and, thus, their subsequent management by change in composition and properties of coal mixture. There were determined indexes CSR/CRI for coke. Fifty – four results were acquired in the experimental parts where correlation between index CRI and coal components were studied. For linear regression the determinant was 55.0204%, between parameters CRI – Inertinit 21.5873%. For regression between CRI and coal components it was 31.03%. For multiple linear regression between CRI and 3 feedstock components determinant was 34.0691%. The final correlation has shown the decrease in final coke reactivity for higher ash, higher content of volatile combustible in coal increases the total coke reactivity and higher amount of inertinit in coal increases the reactivity. Generally, coke quality is significantly affected by coal processing, carbonization and maceral content of coal mixture.

  8. Charging effects of PET under electron beam irradiation in a SEM

    International Nuclear Information System (INIS)

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

    2008-01-01

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

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

    KAUST Repository

    Chen, Xiankai

    2016-09-05

    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.

  10. Effect of thermal contact resistances on fast charging of large format lithium ion batteries

    International Nuclear Information System (INIS)

    Ye, Yonghuang; Saw, Lip Huat; Shi, Yixiang; Somasundaram, Karthik; Tay, Andrew A.O.

    2014-01-01

    Highlights: • The effect of thermal contact resistance on thermal performance of large format lithium ion batteries. • The effect of temperature gradient on electrochemical performance of large format batteries during fast charging. • The thermal performance of lithium ion battery utilizing pulse charging protocol. • Suggestions on battery geometry design optimization to improve thermal performance. - Abstract: A two dimensional electrochemical thermal model is developed on the cross-plane of a laminate stack plate pouch lithium ion battery to study the thermal performance of large format batteries. The effect of thermal contact resistance is taken into consideration, and is found to greatly increase the maximum temperature and temperature gradient of the battery. The resulting large temperature gradient would induce in-cell non-uniformity of charging-discharging current and state of health. Simply increasing the cooling intensity is inadequate to reduce the maximum temperature and narrow down the temperature difference due to the poor cross-plane thermal conductivity. Pulse charging protocol does not help to mitigate the temperature difference on the bias of same total charging time, because of larger time-averaged heat generation rate than constant current charging. Suggestions on battery geometry optimizations for both prismatic/pouch battery and cylindrical battery are proposed to reduce the maximum temperature and mitigate the temperature gradient within the lithium ion battery

  11. Phase separation in La-Ca manganites: Magnetic field effects

    International Nuclear Information System (INIS)

    Tovar, M.; Causa, M.T.; Ramos, C.A.; Laura-Ccahuana, D.

    2008-01-01

    The coexistence of magnetic phases seems to be a characteristic of the La-Ca family of in colossal magnetoresistant manganites. We have analyzed this phenomenon in terms of a free energy, F, where magnetic and electronic contributions of two coexistent phases are included. Three order parameters describe the behavior of the mixed material: the magnetization of each phase and the metallic fraction. Due to the coupling between order parameters there is a range: T**≤T≤T* where coexistence is possible. Values for the phenomenological parameters are obtained from the experiment. In this paper we analyze the effects of an applied magnetic field on the range of T where the phase coexistence takes place, based on results obtained from dc-magnetization and ESR measurements

  12. Phase separation in La-Ca manganites: Magnetic field effects

    Energy Technology Data Exchange (ETDEWEB)

    Tovar, M; Causa, M T [Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica and Universidad Nacional de Cuyo, 8400 San Carlos de Bariloche, Rio Negro (Argentina); Ramos, C.A. [Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica and Universidad Nacional de Cuyo, 8400 San Carlos de Bariloche, Rio Negro (Argentina)], E-mail: cramos@cab.cnea.gov.ar; Laura-Ccahuana, D [Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica and Universidad Nacional de Cuyo, 8400 San Carlos de Bariloche, Rio Negro (Argentina); Universidad Nacional de Ingenieria, Av. Tupac Amaru 210, Rimac/Lima 25 (Peru)

    2008-02-15

    The coexistence of magnetic phases seems to be a characteristic of the La-Ca family of in colossal magnetoresistant manganites. We have analyzed this phenomenon in terms of a free energy, F, where magnetic and electronic contributions of two coexistent phases are included. Three order parameters describe the behavior of the mixed material: the magnetization of each phase and the metallic fraction. Due to the coupling between order parameters there is a range: T**{<=}T{<=}T* where coexistence is possible. Values for the phenomenological parameters are obtained from the experiment. In this paper we analyze the effects of an applied magnetic field on the range of T where the phase coexistence takes place, based on results obtained from dc-magnetization and ESR measurements.

  13. Effects of separator breakdown on abuse response of 18650 Li-ion cells

    Energy Technology Data Exchange (ETDEWEB)

    Roth, E.P.; Doughty, D.H.; Pile, D.L. [Sandia National Laboratories, PO Box 5800, Albuquerque, NM 87185-0613 (United States)

    2007-12-06

    The thermal abuse tolerance of Li-ion cells depends not only on the stability of the active materials in the anode and cathode but also on the stability of the separator which prevents direct interaction between these electrodes. Separator response has been measured as a function of temperature and high voltage both for isolated materials and in full 18650 cells. Separators with different compositions and properties were measured to determine the effect of separator melt integrity on cell response under abusive conditions. These studies were performed as part of the U.S. Department of Energy (DOE) Advanced Technology Development (ATD) Program. (author)

  14. Effect of heat treatment duration on phase separation of sodium borosilicate glass, containing copper

    International Nuclear Information System (INIS)

    Shejnina, T.G.; Gutner, S.Kh.; Anan'in, N.I.

    1989-01-01

    The effect of heat treatment duration on phase separation of sodium borosilicate (SBS) glass, containing copper is studied. It is stated that phase separation close to equilibrium one is attained under 12 hours of heat treatment of SBS glass containing copper

  15. Effect of separation in n-pentane on storability of sugar maple seeds

    Science.gov (United States)

    Clayton M., Jr. Carl

    1976-01-01

    Seeds in samaras separated in n-pentane have been stored successfully for 5½ years. The seeds in the separated samaras germinated equally as well as the unseparated controls, indicating that there was no detrimental effect from the n-pentane.

  16. Jackpot? Gender Differences in the Effects of Lottery Wins on Separation

    Science.gov (United States)

    Boertien, Diederik

    2012-01-01

    In this study, information on small to modest lottery wins from the British Household Panel Survey (N = 2,563) was used to investigate the effect of income on separation. The analysis demonstrated that money matters within relationships. Lottery wins temporarily reduced the odds of separation after men won. Men spent more on leisure and became…

  17. 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)

    2015-10-14

    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.

  18. The effects of different intake charge diluents on the combustion and emission characteristics of a spark ignition natural gas engine

    International Nuclear Information System (INIS)

    He, Zhuoyao; Jing, Qijian; Zhu, Lei; Zhang, Wugao; Huang, Zhen

    2015-01-01

    Exhaust gas recirculation (EGR) is the most common method to control NO_x emission of internal combustion engine. The major components of EGR are CO_2 and N_2, which have different influences on engine combustion and pollutants formation through thermal, dilution and chemical effects. The main objective of this work is to investigate the different influences of CO_2 and N_2 on engine combustion and emission on a four-cylinder, turbo charged, spark ignition natural gas engine with electronically control unit, simultaneously to separate the thermal effect with the comparison with Ar. It was found that the peak in-cylinder pressure and heat release rate both decreased along with the increase of intake dilution extent regardless of the diluent's type. For each diluent gas, NO_x emission decreases while HC emission increases with the increased dilution ratio. However, CO emission firstly decreased and then increased. Results also revealed that NO_x and CO emission could be simultaneously reduced by intake charge dilution at a little sacrifice of HC emission. The effects of three diluents are different compared with each other. Among these three diluents, it can be found that CO_2 is the most effective on reducing NO_x and CO emission followed by N_2. However, both CO_2 and N_2 dilution deteriorates the thermal efficiency while Ar dilution improved it. Besides, when NO_x emission was reduced to the same level, the thermal efficiency is the highest and CO emission is the lowest for Ar dilution. - Highlights: • CO_2 is the most effective on reducing NO_x and CO emission followed by N_2 and then Ar. • NO_x and CO emission could be simultaneously reduced by intake charge dilution regardless of the diluents when appropriate dilution extent is chosen. • Both CO_2 and N_2 dilution worsen while Ar dilution improves thermal efficiency. • Thermal effect is a dominant factor for reducing NO_x emission.

  19. Effects of traveling waves on flow separation and turbulence

    Science.gov (United States)

    Akbarzadeh, Amir Mahdi; Borazjani, Iman; scientific computing; biofluids laboratory Team

    2017-11-01

    Stable leading edge vortex (LEV) is observed in many flying, hovering and also some aquatic creatures. However, the LEV stability in aquatic animal, in contrast to hovering ones, is not well understood. Here, we study the flow over an inclined plate with an undulatory motion inspired from aquatic swimmers using our immersed boundary, large-eddy simulations (LES). The angle of attack is five degrees and Reynolds number (Re) is 20,000. The undulation is a traveling wave, which has a constant amplitude of 0.01 with respect to chord length and a different wavelength and Strouhal number (St =fA/U, f: frequency, A: amplitude, and U: free stream velocity) for each case. Over a fixed plate the LEV becomes unstable as it reaches the trailing edge and sheds to the wake, whereas over the undulating plate with St =0.2 the LEV becomes stable. The visualization of time average results shows there is a favorable pressure gradient along the tangential direction in cases the LEV becomes stable, which we explain analytically by showing the correlation between the average pressure gradient, St, and wavelength. Finally, the effects of undulatory moving walls of a channel flow on the turbulent statistics is shown. This work was partly supported by the National Science Foundation (NSF) CAREER Grant CBET 1453982, and the Center of Computational Research (CCR) of University at Buffalo.

  20. Fuel fragmentation data review and separate effects testing

    International Nuclear Information System (INIS)

    Yueh, Ken. H.; Snis, N.; Mitchell, D.; Munoz-Reja, C.

    2014-01-01

    A simple alternative test has been developed to study the fuel fragmentation process at loss of coolant accident (LOCA) temperatures. The new test heats a short section of fuel, approximately two pellets worth of material, in a tube furnace open to air. An axial slit is cut in the test sample cladding to reduce radial restraint and to simulate ballooned condition. The tube furnace allows the fuel fragmentation process be observed during the experiment. The test was developed as a simple alternative so large number of tests could be conducted quickly and efficiently to identify key variables that influence fuel fragmentation and to zeroing on the fuel fragmentation burn-up threshold. Several tests were conducted, using fuel materials from fuel rods that were used in earlier integral tests to benchmark and validate the test technique. High burn-up fuel materials known to be above the fragmentation threshold was used to evaluate the fragmentation process as a function of temperature. Even with an axial slit and both ends open, no significant fuel detachment/release was detected until above 750°C. Additional tests were conducted with fuel materials at burn-ups closer to the fuel fragmentation burn-up threshold. Results from these tests indicate a minor power history effect on the fuel fragmentation burn-up threshold. An evaluation of available literature and data generated from this work suggest a fuel fragmentation burn-up threshold between 70 and 75 GWd/MTU. (author)

  1. Charges in gravitational fields: From Fermi, via Hanni-Ruffini-Wheeler, to the 'electric Meissner effect'

    Science.gov (United States)

    Ruffini, R.

    2004-07-01

    Recent developments in obtaining a detailed model for gamma-ray bursts have shown the need for a deeper understanding of phenomena described by solutions of the Einstein-Maxwell equations, reviving interest in the behavior of charges close to a black hole. In particular a drastic difference has been found between the lines of force of a charged test particle in the fields of Schwarzschild and Reissner-Nordström black holes. This difference characterizes a general relativistic effect for the electric field of a charged test particle around a (charged) Reissner-Nordström black hole similar to the “Meissner effect” for a magnetic field around a superconductor. These new results are related to earlier work by Fermi and Hanni-Ruffini-Wheeler.

  2. Effect of plasma-induced surface charging on catalytic processes: application to CO2 activation

    Science.gov (United States)

    Bal, Kristof M.; Huygh, Stijn; Bogaerts, Annemie; Neyts, Erik C.

    2018-02-01

    Understanding the nature and effect of the multitude of plasma-surface interactions in plasma catalysis is a crucial requirement for further process development and improvement. A particularly intriguing and rather unique property of a plasma-catalytic setup is the ability of the plasma to modify the electronic structure, and hence chemical properties, of the catalyst through charging, i.e. the absorption of excess electrons. In this work, we develop a quantum chemical model based on density functional theory to study excess negative surface charges in a heterogeneous catalyst exposed to a plasma. This method is specifically applied to investigate plasma-catalytic CO2 activation on supported M/Al2O3 (M = Ti, Ni, Cu) single atom catalysts. We find that (1) the presence of a negative surface charge dramatically improves the reductive power of the catalyst, strongly promoting the splitting of CO2 to CO and oxygen, and (2) the relative activity of the investigated transition metals is also changed upon charging, suggesting that controlled surface charging is a powerful additional parameter to tune catalyst activity and selectivity. These results strongly point to plasma-induced surface charging of the catalyst as an important factor contributing to the plasma-catalyst synergistic effects frequently reported for plasma catalysis.

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

    KAUST Repository

    Sutton, Christopher; Tummala, Naga Rajesh; Kemper, Travis; Aziz, Saadullah G.; Sears, John; Coropceanu, Veaceslav; Bredas, Jean-Luc

    2017-01-01

    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.

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

    KAUST Repository

    Sutton, Christopher

    2017-06-13

    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.

  5. Separation of racemic mixture by ultrafiltration of enantioselective micelles. 1 Effect of pH on separation and regeneration

    NARCIS (Netherlands)

    Overdevest, P.E.M.; Bruin, de T.J.M.; Riet, van 't K.; Keurentjes, J.T.F.; Padt, van der A.

    2001-01-01

    Many enantiomer separation systems are studied to meet the increasing demand for enantiopure compounds. One way to obtain pure enantiomers is to apply enantioselective micelles in ultrafiltration systems. We have studied the separation of phenylalanine (Phe) enantiomers by the ultrafiltration of

  6. Special raster scanning for reduction of charging effects in scanning electron microscopy.

    Science.gov (United States)

    Suzuki, Kazuhiko; Oho, Eisaku

    2014-01-01

    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.

  7. Radiation gradient isotope separator

    International Nuclear Information System (INIS)

    Hughes, J.L.

    1980-01-01

    A system is described for transporting, separating and storing charged particles, charged antiparticles and fully or partially ionized isotopes of any element comprising a laser beam generator, laser beam intensity profiler, a laser beam variable intensity attenuator, and means for injecting charged particles, charged antiparticles and ionized isotopes into the beam and extracting them from the system as required. The invention is particularly useful for channelling electrons and ions used for fuel pellet compression in inertial fusion systems, for separating the isotopes of elements and for the confinement of charged antiparticles and particle/antiparticle plasmas

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

    Indian Academy of Sciences (India)

    Orifjon Ganiev

    2017-05-30

    May 30, 2017 ... sizes and effective masses are large polarons. According ... nating metallic and insulating domains with mobile ... The mobile polaronic carriers are con- ..... [51] T Kondo, Y Hamaya, A D Palczewski, T Takeuchi, J S Wen,.

  9. Fabrication of a Co(OH)2/ZnCr LDH "p-n" Heterojunction Photocatalyst with Enhanced Separation of Charge Carriers for Efficient Visible-Light-Driven H2 and O2 Evolution.

    Science.gov (United States)

    Sahoo, Dipti Prava; Nayak, Susanginee; Reddy, K Hemalata; Martha, Satyabadi; Parida, Kulamani

    2018-04-02

    Photocatalytic generation of H 2 and O 2 by water splitting remains a great challenge for clean and sustainable energy. Taking into the consideration promising heterojunction photocatalysts, analogous energy issues have been mitigated to a meaningful extent. Herein, we have architectured a highly efficient bifunctional heterojunction material, i.e., p-type Co(OH) 2 platelets with an n-type ZnCr layered double hydroxide (LDH) by an ultrasonication method. Primarily, the Mott-Schottky measurements confirmed the n- and p-type semiconductive properties of LDH and CH material, respectively, with the construction of a p-n heterojunction. The high resolution transmission electron microscopy results suggest that surface modification of ZnCr LDH by Co(OH) 2 hexagonal platelets could form a fabulous p-n interfacial region that significantly decreases the energy barrier for O 2 and H 2 production by effectively separating and transporting photoinduced charge carriers, leading to enhanced photoreactivity. A deep investigation into the mechanism shows that a 30 wt % Co(OH) 2 -modified ZnCr LDH sample liberates maximum H 2 and O 2 production in 2 h, i.e., 1115 and 560 μmol, with apparent conversion efficiencies of H 2 and O 2 evolution of 13.12% and 6.25%, respectively. Remarkable photocatalytic activity with energetic charge pair transfer capability was illustrated by electrochemical impedance spectroscopy, linear sweep voltammetry, and photoluminescence spectra. The present study clearly suggests that low-cost Co(OH) 2 platelets are the most crucial semiconductors to provide a new p-n heterojunction photocatalyst for photocatalytic H 2 and O 2 production on the platform of ZnCr LDH.

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

    Directory of Open Access Journals (Sweden)

    O. Havnes

    2007-03-01

    Full Text Available The dust probe DUSTY, first launched during the summer of 1994 (flights ECT–02 and ECT–07 from Andøya 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 ωR. Observations show, however, that the observed currents are strongly modulated at 2ωR. 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

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

    Directory of Open Access Journals (Sweden)

    O. Havnes

    2007-03-01

    Full Text Available The dust probe DUSTY, first launched during the summer of 1994 (flights ECT–02 and ECT–07 from Andøya 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 ωR. Observations show, however, that the observed currents are strongly modulated at 2ωR. 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

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

    Science.gov (United States)

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

    2015-12-01

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

  13. 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)

    2008-10-30

    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.

  14. Nature of the Charged-Group Effect on the Stability of the C-Peptide Helix

    Science.gov (United States)

    Shoemaker, Kevin R.; Kim, Peter S.; Brems, David N.; Marqusee, Susan; York, Eunice J.; Chaiken, Irwin M.; Stewart, John M.; Baldwin, Robert L.

    1985-04-01

    The residues responsible for the pH-dependent stability of the helix formed by the isolated C-peptide (residues 1-13 of ribonuclease A) have been identified by chemical synthesis of analogues and measurement of their helix-forming properties. Each of the residues ionizing between pH 2 and pH 8 has been replaced separately by an uncharged residue. Protonation of Glu-2- is responsible for the sharp decrease in helix stability between pH 5 and pH 2, and deprotonation of His-12+ causes a similar decrease between pH 5 and pH 8. Glu-9- is not needed for helix stability. The results cannot be explained by the Zimm-Bragg model and host-guest data for α -helix formation, which predict that the stability of the C-peptide helix should increase when Glu-2- is protonated or when His-12+ is deprotonated. Moreover, histidine+ is a strong helix-breaker in host-guest studies. In proteins, acidic and basic residues tend to occur at opposite ends of α -helices: acidic residues occur preferentially near the NH2-terminal end and basic residues near the COOH-terminal end. A possible explanation, based on a helix dipole model, has been given [Blagdon, D. E. & Goodman, M. (1975) Biopolymers 14, 241-245]. Our results are consistent with the helix dipole model and they support the suggestion that the distribution of charged residues in protein helices reflects the helix-stabilizing propensity of those residues. Because Glu-9 is not needed for helix stability, a possible Glu-9-\\cdots His-12+ salt bridge does not contribute significantly to helix stability. The role of a possible Glu-2-\\cdots Arg-10+ salt bridge has not yet been evaluated. A charged-group effect on α -helix stability in water has also been observed in a different peptide system [Ihara, S., Ooi, T. & Takahashi, S. (1982) Biopolymers 21, 131-145]: block copolymers containing (Ala)20 and (Glu)20 show partial helix formation at low temperatures, pH 7.5, where the glutamic acid residues are ionized. (Glu)20(Ala)20Phe forms a

  15. MoS2 quantum dots@TiO2 nanotube composites with enhanced photoexcited charge separation and high-efficiency visible-light driven photocatalysis

    Science.gov (United States)

    Zhao, Fenfen; Rong, Yuefei; Wan, Junmin; Hu, Zhiwen; Peng, Zhiqin; Wang, Bing

    2018-03-01

    MoS2 quantum dots (QDs) that are 5 nm in size were deposited on the surface of ultrathin TiO2 nanotubes (TNTs) with 5 nm wall thickness by using an improved hydrothermal method to form a MoS2 QDs@TNT visible-light photocatalyst. The ultrathin TNTs with high percentage of photocatalytic reactive facets were fabricated by the commercially available TiO2 nanoparticles (P25) through an improved hydrothermal method, and the MoS2 QDs were acquired by using a surfactant-assisted technique. The novel MoS2 QDs@TNT photocatalysts showed excellent photocatalytic activity with a decolorization rate of 92% or approximately 3.5 times more than that of pure TNTs for the high initial concentration of methylene blue solution (20 mg l-1) within 40 min under visible-light irradiation. MoS2 as the co-catalysts favored the broadening of TNTs into the visible-light absorption scope. The quantum confinement and edge effects of the MoS2 QDs and the heterojunction formed between the MoS2 QDs and TNTs efficiently extended the lifetime of photoinduced charges, impeded the recombination of photoexcited electron-hole pairs, and improved the visible-light-driven high-efficiency photocatalysis.

  16. Direct observation of single-charge-detection capability of nanowire field-effect transistors.

    Science.gov (United States)

    Salfi, J; Savelyev, I G; Blumin, M; Nair, S V; Ruda, H E

    2010-10-01

    A single localized charge can quench the luminescence of a semiconductor nanowire, but relatively little is known about the effect of single charges on the conductance of the nanowire. In one-dimensional nanostructures embedded in a material with a low dielectric permittivity, the Coulomb interaction and excitonic binding energy are much larger than the corresponding values when embedded in a material with the same dielectric permittivity. The stronger Coulomb interaction is also predicted to limit the carrier mobility in nanowires. Here, we experimentally isolate and study the effect of individual localized electrons on carrier transport in InAs nanowire field-effect transistors, and extract the equivalent charge sensitivity. In the low carrier density regime, the electrostatic potential produced by one electron can create an insulating weak link in an otherwise conducting nanowire field-effect transistor, modulating its conductance by as much as 4,200% at 31 K. The equivalent charge sensitivity, 4 × 10(-5) e Hz(-1/2) at 25 K and 6 × 10(-5) e Hz(-1/2) at 198 K, is orders of magnitude better than conventional field-effect transistors and nanoelectromechanical systems, and is just a factor of 20-30 away from the record sensitivity for state-of-the-art single-electron transistors operating below 4 K (ref. 8). This work demonstrates the feasibility of nanowire-based single-electron memories and illustrates a physical process of potential relevance for high performance chemical sensors. The charge-state-detection capability we demonstrate also makes the nanowire field-effect transistor a promising host system for impurities (which may be introduced intentionally or unintentionally) with potentially long spin lifetimes, because such transistors offer more sensitive spin-to-charge conversion readout than schemes based on conventional field-effect transistors.

  17. Calculating potential of mean force between like-charged nanoparticles: A comprehensive study on salt effects

    International Nuclear Information System (INIS)

    Wu, Yuan-Yan; Wang, Feng-Hua; Tan, Zhi-Jie

    2013-01-01

    Ions are critical to the structure and stability of polyelectrolytes such as nucleic acids. In this work, we systematically calculated the potentials of mean force between two like-charged nanoparticles in salt solutions by Monte Carlo simulations. The pseudo-spring method is employed to calculate the potential of mean force and compared systematically with the inversed-Boltzmann method. An effective attraction is predicted between two like-charged nanoparticles in divalent/trivalent salt solution and such attraction becomes weakened at very high salt concentration. Our analysis reveals that for the system, the configuration of ion-bridging nanoparticles is responsible for the attraction, and the invasion of anions into the inter-nanoparticles region at high salt concentration would induce attraction weakening rather than the charge inversion effect. The present method would be useful for calculating effective interactions during nucleic acid folding.

  18. Charge distribution effects in polyatomic reactants involved in simple electron transfer reactions

    Czech Academy of Sciences Publication Activity Database

    Fawcett, W. R.; Chavis, G. J.; Hromadová, Magdaléna

    2008-01-01

    Roč. 53, č. 23 (2008), s. 6787-6792 ISSN 0013-4686 Institutional research plan: CEZ:AV0Z40400503 Keywords : electron transfer kinetics * charge distribution effects * double - layer effects in electrode kinetics Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.078, year: 2008

  19. Oil Contact Angles in a Water-Decane-Silicon Dioxide System: Effects of Surface Charge.

    Science.gov (United States)

    Xu, Shijing; Wang, Jingyao; Wu, Jiazhong; Liu, Qingjie; Sun, Chengzhen; Bai, Bofeng

    2018-04-19

    Oil wettability in the water-oil-rock systems is very sensitive to the evolution of surface charges on the rock surfaces induced by the adsorption of ions and other chemical agents in water flooding. Through a set of large-scale molecular dynamics simulations, we reveal the effects of surface charge on the oil contact angles in an ideal water-decane-silicon dioxide system. The results show that the contact angles of oil nano-droplets have a great dependence on the surface charges. As the surface charge density exceeds a critical value of 0.992 e/nm 2 , the contact angle reaches up to 78.8° and the water-wet state is very apparent. The variation of contact angles can be confirmed from the number density distributions of oil molecules. With increasing the surface charge density, the adsorption of oil molecules weakens and the contact areas between nano-droplets and silicon dioxide surface are reduced. In addition, the number density distributions, RDF distributions, and molecular orientations indicate that the oil molecules are adsorbed on the silicon dioxide surface layer-by-layer with an orientation parallel to the surface. However, the layered structure of oil molecules near the silicon dioxide surface becomes more and more obscure at higher surface charge densities.

  20. Effect of ion suprathermality on arbitrary amplitude dust acoustic waves in a charge varying dusty plasma

    International Nuclear Information System (INIS)

    Tribeche, Mouloud; Mayout, Saliha; Amour, Rabia

    2009-01-01

    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)].

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

    International Nuclear Information System (INIS)

    Cardia, R.; Malloci, G.; Bosin, A.; Serra, G.; Cappellini, G.

    2016-01-01

    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.

  2. Effect of substrate bias on deposition behaviour of charged silicon nanoparticles in ICP-CVD process

    International Nuclear Information System (INIS)

    Yoo, Seung-Wan; Kim, Jung-Hyung; Seong, Dae-Jin; You, Shin-Jae; Seo, Byong-Hoon; Hwang, Nong-Moon

    2017-01-01

    The effect of a substrate bias on the deposition behaviour of crystalline silicon films during inductively coupled plasma chemical vapour deposition (ICP-CVD) was analysed by consideration of non-classical crystallization, in which the building block is a nanoparticle rather than an individual atom or molecule. The coexistence of positively and negatively charged nanoparticles in the plasma and their role in Si film deposition are confirmed by applying bias voltages to the substrate, which is sufficiently small as not to affect the plasma potential. The sizes of positively and negatively charged nanoparticles captured on a carbon membrane and imaged using TEM are, respectively, 2.7–5.5 nm and 6–13 nm. The film deposited by positively charged nanoparticles has a typical columnar structure. In contrast, the film deposited by negatively charged nanoparticles has a structure like a powdery compact with the deposition rate about three times higher than that for positively charged nanoparticles. All the films exhibit crystallinity even though the substrate is at room temperature, which is attributed to the deposition of crystalline nanoparticles formed in the plasma. The film deposited by negatively charged nanoparticles has the highest crystalline fraction of 0.84. (paper)

  3. 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: giuliano.malloci@dsf.unica.it [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: giancarlo.cappellini@dsf.unica.it [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)

    2016-10-20

    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.

  4. 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)

    2007-07-01

    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

  5. Study on the separation effect of high-speed ultrasonic vibration cutting.

    Science.gov (United States)

    Zhang, Xiangyu; Sui, He; Zhang, Deyuan; Jiang, Xinggang

    2018-07-01

    High-speed ultrasonic vibration cutting (HUVC) has been proven to be significantly effective when turning Ti-6Al-4V alloy in recent researches. Despite of breaking through the cutting speed restriction of the ultrasonic vibration cutting (UVC) method, HUVC can also achieve the reduction of cutting force and the improvements in surface quality and cutting efficiency in the high-speed machining field. These benefits all result from the separation effect that occurs during the HUVC process. Despite the fact that the influences of vibration and cutting parameters have been discussed in previous researches, the separation analysis of HUVC should be conducted in detail in real cutting situations, and the tool geometry parameters should also be considered. In this paper, three situations are investigated in details: (1) cutting without negative transient clearance angle and without tool wear, (2) cutting with negative transient clearance angle and without tool wear, and (3) cutting with tool wear. And then, complete separation state, partial separation state and continuous cutting state are deduced according to real cutting processes. All the analysis about the above situations demonstrate that the tool-workpiece separation will take place only if appropriate cutting parameters, vibration parameters, and tool geometry parameters are set up. The best separation effect was obtained with a low feedrate and a phase shift approaching 180 degrees. Moreover, flank face interference resulted from the negative transient clearance angle and tool wear contributes to an improved separation effect that makes the workpiece and tool separate even at zero phase shift. Finally, axial and radial transient cutting force are firstly obtained to verify the separation effect of HUVC, and the cutting chips are collected to weigh the influence of flank face interference. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Charge Transfer Nanocomposites: The Effects of Scale-Hierarchy

    Science.gov (United States)

    2006-12-31

    Ph. (336) 768 5508 Phone: (703) 696-7779 Email: carroldl@wfu.edu Fax: (703) 696-8449 Performing Institution: Email: charles.leee ,afosr.af.mil The...transmittance at low fluences. We suggest that the HITCI’s RSA properties at low fluences are modified through "antenna-like" effects by the blended...transmission device: (1) multi-photon absorption, (2) reverse saturable absorption ( RSA ), (3) and nonlinear scattering. Comparatively, little research has

  7. Negative space charge effects in photon-enhanced thermionic emission solar converters

    International Nuclear Information System (INIS)

    Segev, G.; Weisman, D.; Rosenwaks, Y.; Kribus, A.

    2015-01-01

    In thermionic energy converters, electrons in the gap between electrodes form a negative space charge and inhibit the emission of additional electrons, causing a significant reduction in conversion efficiency. However, in Photon Enhanced Thermionic Emission (PETE) solar energy converters, electrons that are reflected by the electric field in the gap return to the cathode with energy above the conduction band minimum. These electrons first occupy the conduction band from which they can be reemitted. This form of electron recycling makes PETE converters less susceptible to negative space charge loss. While the negative space charge effect was studied extensively in thermionic converters, modeling its effect in PETE converters does not account for important issues such as this form of electron recycling, nor the cathode thermal energy balance. Here, we investigate the space charge effect in PETE solar converters accounting for electron recycling, with full coupling of the cathode and gap models, and addressing conservation of both electric and thermal energy. The analysis shows that the negative space charge loss is lower than previously reported, allowing somewhat larger gaps compared to previous predictions. For a converter with a specific gap, there is an optimal solar flux concentration. The optimal solar flux concentration, the cathode temperature, and the efficiency all increase with smaller gaps. For example, for a gap of 3 μm the maximum efficiency is 38% and the optimal flux concentration is 628, while for a gap of 5 μm the maximum efficiency is 31% and optimal flux concentration is 163

  8. Charge-collection efficiency of GaAs field effect transistors fabricated with a low temperature grown buffer layer: dependence on charge deposition profile

    International Nuclear Information System (INIS)

    McMorrow, D.; Knudson, A.R.; Melinger, J.S.; Buchner, S.

    1999-01-01

    The results presented here reveal a surprising dependence of the charge-collection efficiency of LT GaAs FETs (field effect transistors) on the depth profile of the deposited charge. Investigation of the temporal dependence of the signal amplitude, carrier density contours, and potential contours reveals different mechanisms for charge collection arising from carriers deposited above and below the LT GaAs buffer layer, respectively. In particular, carriers deposited below the LT GaAs buffer layer dissipate slowly and give rise to a persistent charge collection that is associated with a bipolar-like gain process. These results may be of significance in understanding the occurrence of single-event upsets from protons, neutrons, and large-angle, glancing heavy-ion strikes. (authors)

  9. Overcoming the inhibitory effect of serum on lipofection by increasing the charge ratio of cationic liposome to DNA.

    Science.gov (United States)

    Yang, J P; Huang, L

    1997-09-01

    Since cationic liposome was first developed as a lipofection reagent, a drawback has been noted in that the efficiency of lipofection decreases dramatically after addition of serum to the lipofection medium. This drawback hampers the application of cationic liposome for systematic delivery of genes. In the present studies, we found that the effect of serum on DC-chol liposome-mediated lipofection is dependent on the charge ratio of liposome to DNA. Serum inhibited lipofection activity of the lipoplex at low charge ratios, whereas it enhanced the lipofection activity at high charge ratios. This phenomenon was observed using DOTAP/DOPE but not lipofectamine. Measurement of cellular association of DNA showed that serum could reduce the binding of lipoplex to cells at all tested charge ratios, i.e. 0-10.6. Removal of negatively charged proteins from serum by DEAE Sephacel column abolished the inhibitory effect of serum on lipofection. The fraction contained only negatively charged serum proteins which strongly inhibited lipofection at low charge ratios but not at higher charge ratios. Furthermore, preincubation of serum with positively charged polylysine, which neutralized negatively charged serum proteins, eliminated the inhibitory effect of serum on lipofection. In summary, inactivation of cationic liposome by serum is due to negatively charged serum proteins and it can be overcome by increasing charge ratio of cationic liposome-DNA lipoplexes or by neutralizing the serum with polylysine.

  10. Neutrino (antineutrino) effective charge in a magnetized electron-positron plasma

    International Nuclear Information System (INIS)

    Serbeto, A.; Rios, L.A.; Mendonca, J.T.; Shukla, P.K.

    2004-01-01

    Using dynamical techniques of the plasma physics, the neutrino (antineutrino) effective charge in a magnetized dense electron-positron plasma is determined here. It shown that its value, which is determined by the plasma collective processes, depends mainly on the propagation direction of plasma waves and neutrinos against the external magnetic field direction. The direction dependence of the effective charge occurs due to the fact that the magnetic field breaks the plasma isotropy. The present theory gives a unified picture of the problem which is valid for an external magnetic field below the Landau-Schwinger critical value. Comparison with some of the results from the quantum field theory has been made

  11. The effective neutrino charge radius in the presence of fermion masses

    International Nuclear Information System (INIS)

    Binosi, D.; Bernabeu, J.; Papavassiliou, J.

    2005-01-01

    We show how the crucial gauge cancellations leading to a physical definition of an effective neutrino charge radius persist in the presence of non-vanishing fermion masses. An explicit one-loop calculation demonstrates that, as happens in the massless case, the pinch technique rearrangement of the Feynman amplitudes, together with the judicious exploitation of the fundamental current relation J α (3) =2(J Z +sinθ w 2 J γ ) α , leads to a completely gauge independent definition of the effective neutrino charge radius. Using the formalism of the Nielsen identities it is further proved that the same cancellation mechanism operates unaltered to all orders in perturbation theory

  12. Separation and recombinatiuon of charge carriers in solar cells with a nanostructured ZnO electrode; Trennung und Rekombination von Ladungstraegern in Solarzellen mit nanostrukturierter ZnO-Elektrode

    Energy Technology Data Exchange (ETDEWEB)

    Tornow, Julian

    2010-03-02

    The publication investigates electrodes consisting of ZnO nanorods deposited hydrothermally on conductive glass substrate (conductive glass). The electrodes are transparent to visible light and are sensitized for solar cell applications by a light-absorbing layer which in this case consists either of organometallic dye molecules (N3) or of an indium sulfide layer with a thickness of only a few nanometers. Electric contacts for the sensitized electrode are either made of a liquid electrolyte or of a perforated solid electrolyte. Methods of analysis were impedance spectroscopy, time-resolved photocurrent measurements, and time-resolved microwave photoconductivity. A high concentration of up to 10{sup 20} was found in the ZnO nanorods. The dye-sensitized solar cell showed exessively fast recombination with the oxydized dye molecules (sub-{mu}s) but a slow recombination rate with the oxydized redox ions of the electrolyte (ms). In the indium sulfide solar cells, the charges are separated at the contact with the ZnO nanorods while contact with the perforated CuSCN conductor is not charge-separating. Recombination takes place in indium sulfide, directly between the perforated conductor and ZnO, and also via the charge-separating contact with decreasing rates.

  13. Effect of MoO3 addition on phase separation in borosilicate glasses

    International Nuclear Information System (INIS)

    Wakabayashi, Hajimu; Yamanaka, Hiroshi; Terai, Ryohei; Fukumoto, Shinji.

    1987-01-01

    The effect of MoO 3 addition on the phase separation of sodium borosilicate glasses has been studied by electron microscopic observation and electrical conductivity measurement. With increasing MoO 3 addition, the immiscibility temperatures rose, the growth rate of phase separation increased, and the immiscibility region in the Na 2 O-B 2 O 3 -SiO 2 system extended. When MoO 3 more than 5 mol% was added to the glasses, two stages of phase separation appeared ; one is metastable immiscibility, which takes place below the liquidus temperature, and the other is stable immiscibility, occurring above the liquidus temperature. The present experiment confirmed that the conductivity measurement of molten glasses is usefull to detect phase separation in the glasses, giving some suggestions for preventing the separation of molybdates in nuclear waste glasses and also for controlling the micro-pore sizes of porous glasses. (author)

  14. Gas-surface dynamics and charging effects during plasma processing of semiconductors

    Science.gov (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.)

  15. Probing inhibitory effects of nanocrystalline cellulose: inhibition versus surface charge

    Science.gov (United States)

    Male, Keith B.; Leung, Alfred C. W.; Montes, Johnny; Kamen, Amine; Luong, John H. T.

    2012-02-01

    NCC derived from different biomass sources was probed for its plausible cytotoxicity by electric cell-substrate impedance sensing (ECIS). Two different cell lines, Spodoptera frugiperda Sf9 insect cells and Chinese hamster lung fibroblast V79, were exposed to NCC and their spreading and viability were monitored and quantified by ECIS. Based on the 50%-inhibition concentration (ECIS50), none of the NCC produced was judged to have any significant cytotoxicity on these two cell lines. However, NCC derived from flax exhibited the most pronounced inhibition on Sf9 compared to hemp and cellulose powder. NCCs from flax and hemp pre-treated with pectate lyase were also less inhibitory than NCCs prepared from untreated flax and hemp. Results also suggested a correlation between the inhibitory effect and the carboxylic acid contents on the NCC.

  16. Space-charge effects on bunching of electrons in the CEBAF injector

    International Nuclear Information System (INIS)

    Liu, H.

    1997-01-01

    The main injector for the 4 GeV CEBAF accelerator at Thomas Jefferson national accelerator facility was designed to deliver simultaneously three CW electron beams for nuclear physics research. The maximum design current for a single beam from the injector is 100 μA, or 0.2 pC per microbunch at a repetition rate of 499 MHz. It was found through computer simulation that space charge even at a subpicocoulomb level can spoil the bunching of electrons significantly, and some unexpected phenomena observed experimentally could be explained accordingly. This problem arises because of the low-momentum tilt allowed for bunching to preserve low-momentum spread. In this paper, we analyze in detail the space-charge effects on bunching of electrons with the CEBAF injector as an example. Conditions for effective matching of longitudinal phase space in the presence of space charge are discussed. (orig.)

  17. Search for space charge effects in the ICARUS T600 LAr-TPC

    Science.gov (United States)

    Torti, Marta

    2016-11-01

    Space charge in Liquid Argon Time Projection Chamber is due to the accumu- lation of positive ions, produced by ionizing tracks crossing the detector, which slowly flow toward the cathode. As a consequence, electric field distortions may arise, thus hindering the possibility to produce faithful 3D images of the ionizing events. The presence of space charge becomes relevant for large TPCs operating at surface or at shallow depths, where cosmic ray flux is high. These effects could interest the next phase of the ICARUS T600 detector, which will be deployed at shallow depths as a Far Detector for Short Baseline Neutrino experiment at FNAL dedicated to sterile neutrino searches. In 2001, the first ICARUS T600 module (T300) operated at surface in Pavia (Italy), recording cosmic ray data. In this work, a sample of cosmic muon tracks from the 2001 run was analyzed and results on space charge effects in LAr-TPCs are shown.

  18. Search for space charge effects in the ICARUS T600 LAr-TPC

    International Nuclear Information System (INIS)

    Torti, Marta

    2016-01-01

    Space charge in Liquid Argon Time Projection Chamber is due to the accumu- lation of positive ions, produced by ionizing tracks crossing the detector, which slowly flow toward the cathode. As a consequence, electric field distortions may arise, thus hindering the possibility to produce faithful 3D images of the ionizing events. The presence of space charge becomes relevant for large TPCs operating at surface or at shallow depths, where cosmic ray flux is high. These effects could interest the next phase of the ICARUS T600 detector, which will be deployed at shallow depths as a Far Detector for Short Baseline Neutrino experiment at FNAL dedicated to sterile neutrino searches. In 2001, the first ICARUS T600 module (T300) operated at surface in Pavia (Italy), recording cosmic ray data. In this work, a sample of cosmic muon tracks from the 2001 run was analyzed and results on space charge effects in LAr-TPCs are shown

  19. Charge Transfer Effect on Raman and Surface Enhanced Raman Spectroscopy of Furfural Molecules.

    Science.gov (United States)

    Wan, Fu; Shi, Haiyang; Chen, Weigen; Gu, Zhaoliang; Du, Lingling; Wang, Pinyi; Wang, Jianxin; Huang, Yingzhou

    2017-08-02

    The detection of furfural in transformer oil through surface enhanced Raman spectroscopy (SERS) is one of the most promising online monitoring techniques in the process of transformer aging. In this work, the Raman of individual furfural molecules and SERS of furfural-M x (M = Ag, Au, Cu) complexes are investigated through density functional theory (DFT). In the Raman spectrum of individual furfural molecules, the vibration mode of each Raman peak is figured out, and the deviation from experimental data is analyzed by surface charge distribution. In the SERS of furfural-M x complexes, the influence of atom number and species on SERS chemical enhancement factors (EFs) are studied, and are further analyzed by charge transfer effect. Our studies strengthen the understanding of charge transfer effect in the SERS of furfural molecules, which is important in the online monitoring of the transformer aging process through SERS.

  20. Paraxial charge compensator for electron cryomicroscopy

    International Nuclear Information System (INIS)

    Berriman, John A.; Rosenthal, Peter B.

    2012-01-01

    We describe a multi-hole condenser aperture for the production of several electron beams in the transmission electron microscope (TEM) making it possible to simultaneously image and irradiate spatially separated regions of a specimen. When the specimen is a thin film of vitreous ice suspended over a holey carbon film, simultaneous irradiation of the adjacent carbon support with the off-axis beam compensates for some of the effects of charging in the image formed by a beam irradiating only the ice. Because the intervening region is not irradiated, charge-neutralization of frozen-hydrated specimens can occur by a through-space mechanism such as the emission of secondary electrons from a grounded carbon support film. We use paraxial charge compensation (PCC) to control the amount of charge build-up on the specimen and observe the effects of charge on images. The multi-hole aperture thus provides a tool for investigating the mechanism of charging and charge mitigation during the imaging of radiation sensitive biological specimens by cryomicroscopy. -- Highlights: ► A multi-hole condenser aperture produces multiple (paraxial) beams in TEM. ► Paraxial charge compensation is used to study electron-optical effects of charging. ► Emission of secondary electrons controls charging by a through space mechanism. ► Paraxial beams compensate for charging effects in frozen-hydrated specimens.

  1. Paraxial charge compensator for electron cryomicroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Berriman, John A. [Division of Physical Biochemistry, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA (United Kingdom); Rosenthal, Peter B., E-mail: peter.rosenthal@nimr.mrc.ac.uk [Division of Physical Biochemistry, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA (United Kingdom)

    2012-05-15

    We describe a multi-hole condenser aperture for the production of several electron beams in the transmission electron microscope (TEM) making it possible to simultaneously image and irradiate spatially separated regions of a specimen. When the specimen is a thin film of vitreous ice suspended over a holey carbon film, simultaneous irradiation of the adjacent carbon support with the off-axis beam compensates for some of the effects of charging in the image formed by a beam irradiating only the ice. Because the intervening region is not irradiated, charge-neutralization of frozen-hydrated specimens can occur by a through-space mechanism such as the emission of secondary electrons from a grounded carbon support film. We use paraxial charge compensation (PCC) to control the amount of charge build-up on the specimen and observe the effects of charge on images. The multi-hole aperture thus provides a tool for investigating the mechanism of charging and charge mitigation during the imaging of radiation sensitive biological specimens by cryomicroscopy. -- Highlights: Black-Right-Pointing-Pointer A multi-hole condenser aperture produces multiple (paraxial) beams in TEM. Black-Right-Pointing-Pointer Paraxial charge compensation is used to study electron-optical effects of charging. Black-Right-Pointing-Pointer Emission of secondary electrons controls charging by a through space mechanism. Black-Right-Pointing-Pointer Paraxial beams compensate for charging effects in frozen-hydrated specimens.

  2. Effective charges in nuclei in the vicinity of $^{100}SN$

    CERN Document Server

    Ekström, Andreas

    The shell structure of atomic nuclei far from the line of beta-stability and the properties of the nucleon-nucleon interaction in exotic isotopes are not well known. The development of radioactive ion beams (RIBs) puts certain unexplored regions of the nuclear chart within reach of detailed experimental investigations. The low-energy nuclear structure of the unstable isotopes 106,108,110Sn, 100,102,104Cd, and 106,108In have been studied using sub-barrier Coulomb excitation of postaccelerated RIBs. The experiments were carried out at the REX-ISOLDE facility at CERN. The deduced transition probabilities - B(E2) values - provide a detailed benchmark of modern models of the nucleon-nucleon interaction. The B(E2) values between the 0+ ground states and the first excited 2+ states in the Sn and Cd isotopes were compared with shell-model calculations. These are based on effective interactions derived from renormalized multi-meson and QCD-based nucleon-nucleon potentials. In order to reproduce the experimental result...

  3. Method of improving heterogeneous oil reservoir polymer flooding effect by positively-charged gel profile control

    Science.gov (United States)

    Zhao, Ling; Xia, Huifen

    2018-01-01

    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.

  4. Nonuniform Effect of Carrier Separation Efficiency and Light Absorption in Type-II Perovskite Nanowire Solar Cells

    Science.gov (United States)

    Wang, Weiping; He, Jialun; Cao, Yiyan; Kong, Lijing; Zheng, Xuanli; Wu, Yaping; Chen, Xiaohong; Li, Shuping; Wu, Zhiming; Kang, Junyong

    2017-03-01

    Coaxial structures exhibit great potential for the application of high-efficiency solar cells due to the novel mechanism of radial charge separation. Here, we intensively investigate the nonuniform effect of carrier separation efficiency (CSE) and light absorption in perovskite-based type-II coaxial nanowire solar cells (ZnO/CH3NH3PbI3). Results show that the CSE rapidly decreases along the radial direction in the shell, and the value at the outer side becomes extremely low for the thick shell. Besides, the position of the main light absorption gradually moves to the outer side with the increase of the shell thickness. As a result, the external quantum efficiency shows a positional dependence with a maximal value close to the border of the nanowire. Eventually, in our case, it is found that the maximal power conversion efficiency of the solar cells reduces from 19.5 to 17.9% under the effect of the nonuniformity of CSE and light absorption. This work provides a basis for the design of high-efficiency solar cells, especially type-II nanowire solar cells.

  5. Synergistic effects on enantioselectivity of zwitterionic chiral stationary phases for separations of chiral acids, bases, and amino acids by HPLC.

    Science.gov (United States)

    Hoffmann, Christian V; Pell, Reinhard; Lämmerhofer, Michael; Lindner, Wolfgang

    2008-11-15

    In an attempt to overcome the limited applicability scope of earlier proposed Cinchona alkaloid-based chiral weak anion exchangers (WAX) and recently reported aminosulfonic acid-based chiral strong cation exchangers (SCX), which are conceptionally restricted to oppositely charged solutes, their individual chiral selector (SO) subunits have been fused in a combinatorial synthesis approach into single, now zwitterionic, chiral SO motifs. The corresponding zwitterionic ion-exchange-type chiral stationary phases (CSPs) in fact combined the applicability spectra of the parent chiral ion exchangers allowing for enantioseparations of chiral acids and amine-type solutes in liquid chromatography using polar organic mode with largely rivaling separation factors as compared to the parent WAX and SCX CSPs. Furthermore, the application spectrum could be remarkably expanded to various zwitterionic analytes such as alpha- and beta-amino acids and peptides. A set of structurally related yet different CSPs consisting of either a quinine or quinidine alkaloid moiety as anion-exchange subunit and various chiral or achiral amino acids as cation-exchange subunits enabled us to derive structure-enantioselectivity relationships, which clearly provided strong unequivocal evidence for synergistic effects of the two oppositely charged ion-exchange subunits being involved in molecular recognition of zwitterionic analytes by zwitterionic SOs driven by double ionic coordination.

  6. Effect of rheological characteristics and technology of application of a viscoelastic separator on its displacing ability

    Energy Technology Data Exchange (ETDEWEB)

    Gnibidin, V N

    1980-01-01

    Presented are the results of industrial tests of the displacing ability of a viscoelastic separator, obtained by mixing a clay suspension and an aqueous solution of polyacrylamide. It is established that the displacing ability of the viscoelastic separator is determined mainly by the value of the final normal stresses sigma /SUB f/ . The greatest effect from the use of this separator is achieved with sigma /SUB f/ of at least 600 dyne/cm/sup 2/ and a rate of movement of not more than 0.5 m/sec.

  7. Synthetic high-charge organomica: effect of the layer charge and alkyl chain length on the structure of the adsorbed surfactants.

    Science.gov (United States)

    Pazos, M Carolina; Castro, Miguel A; Orta, M Mar; Pavón, Esperanza; Valencia Rios, Jesús S; Alba, María D

    2012-05-15

    A family of organomicas was synthesized using synthetic swelling micas with high layer charge (Na(n)Si(8-n)Al(n)Mg(6)F(4)O(20)·XH(2)O, where n = 2, 3, and 4) exchanged with dodecylammonium and octadecylammonium cations. The molecular arrangement of the surfactant was elucidated on the basis on XRD patterns and DTA. The ordering conformation of the surfactant molecules into the interlayer space of micas was investigated by (13)C, (27)Al, and (29)Si MAS NMR. The arrangement of alkylammonium ions in these high-charge synthetic micas depends on the combined effects of the layer charge of the mica and the chain length of the cation. In the organomicas with dodecylammonium, a transition from a parallel layer to a bilayer-paraffin arrangement is observed when the layer charge of the mica increases. However, when octadecylammonium is the interlayer cation, the molecular arrangement of the surfactant was found to follow the bilayer-paraffin model for all values of layer charge. The amount of ordered conformation all-trans is directly proportional of layer charge.

  8. Effect of thermal annealing on a novel polyamide–imide polymer membrane for aggressive acid gas separations

    KAUST Repository

    Vaughn, Justin T.

    2012-05-01

    A fluorinated, 6FDA based polyamide-imide is investigated for the purification of CH 4 from CO 2 and H 2S containing gas streams. Dense polymer films were thermally annealed and showed that increased annealing temperatures at constant annealing time caused transport behavior that does not resemble physical aging. Free volume increased after annealing at 200°C for 24h relative to annealing at 150°C for the same time. CO 2 and CH 4 permeabilities and diffusivities did not decrease as a result of the higher annealing temperature, and in fact, were shown to increase slightly. A change to the intrinsic microstructure that cannot be described by simple, densification based physical aging is hypothesized to be the reason for this trend. Furthermore, annealing increased CO 2 induced plasticization resistance and a temperature of 200°C was shown to have the greatest effect on plasticization suppression. Annealing at 200°C for 24h suppressed pure gas CO 2 plasticization up to 450psia. Fluorescence spectroscopy revealed increased intramolecular charge transfer, which is presumably due to increased electron conjugation over the N-phenyl bond. Additionally, intermolecular charge transfer increased with thermal annealing, as inferred from fluorescence intensity measurements and XRD patterns. 50/50 CO 2/CH 4 mixed gas permeation measurements reveal stable separation performance up to 1000psia. Ternary mixed gas feeds containing toluene/CO 2/CH 4 and H 2S/CO 2/CH 4 show antiplasticization, but more importantly, selectivity losses due to plasticization did not occur up to 900psia of total feed pressure. These results show that the polyamide-imide family represents a promising class of separation materials for aggressive acid gas purifications. © 2012 Elsevier B.V.

  9. Effect of thermal annealing on a novel polyamide–imide polymer membrane for aggressive acid gas separations

    KAUST Repository

    Vaughn, Justin T.; Koros, William J.; Johnson, J.R.; Karvan, Oguz

    2012-01-01

    A fluorinated, 6FDA based polyamide-imide is investigated for the purification of CH 4 from CO 2 and H 2S containing gas streams. Dense polymer films were thermally annealed and showed that increased annealing temperatures at constant annealing time caused transport behavior that does not resemble physical aging. Free volume increased after annealing at 200°C for 24h relative to annealing at 150°C for the same time. CO 2 and CH 4 permeabilities and diffusivities did not decrease as a result of the higher annealing temperature, and in fact, were shown to increase slightly. A change to the intrinsic microstructure that cannot be described by simple, densification based physical aging is hypothesized to be the reason for this trend. Furthermore, annealing increased CO 2 induced plasticization resistance and a temperature of 200°C was shown to have the greatest effect on plasticization suppression. Annealing at 200°C for 24h suppressed pure gas CO 2 plasticization up to 450psia. Fluorescence spectroscopy revealed increased intramolecular charge transfer, which is presumably due to increased electron conjugation over the N-phenyl bond. Additionally, intermolecular charge transfer increased with thermal annealing, as inferred from fluorescence intensity measurements and XRD patterns. 50/50 CO 2/CH 4 mixed gas permeation measurements reveal stable separation performance up to 1000psia. Ternary mixed gas feeds containing toluene/CO 2/CH 4 and H 2S/CO 2/CH 4 show antiplasticization, but more importantly, selectivity losses due to plasticization did not occur up to 900psia of total feed pressure. These results show that the polyamide-imide family represents a promising class of separation materials for aggressive acid gas purifications. © 2012 Elsevier B.V.

  10. Dipole transitions and Stark effect in the charge-dyon system

    International Nuclear Information System (INIS)

    Mardoyan, Levon; Nersessian, Armen; Sarkisyan, Hayk; Yeghikyan, Vahagn

    2007-01-01

    We consider the dipole transitions and the linear and quadratic Stark effects in the MICZ-Kepler system interpreted as a charge-dyon system. We show that while the linear Stark effect in the ground state is proportional to the azimuth quantum number (and to the sign of the monopole number), the quadratic Stark effect in the ground state is independent of the signs of the azimuth and monopole numbers

  11. Effect of charged particle flux on Bacillus mesentericus and Pseudomonas fluorescens cultures

    International Nuclear Information System (INIS)

    Ostapenkov, A.M.; Kaptereva, Yu.V.; Merinov, N.S.; Lavrova, V.L.

    1979-01-01

    Studied was the effect of a strong electric field and charged particle (aerions) flow on Bac. mesentericus and Ps. fluorescens cultures causing the spoiling of foodstuffs and food raw materials. It has been found, that under the effects of the electric field and positive or negative ions reduced is the Bac. mesentericus and Ps. fluorescens viability, cultivated on a solid nutrient medium; the effect of the electric field only does not affect the Bac. mesentericus viability

  12. EFFECT OF ULTRASOUND ACTIVATION OF SHS-CHARGE ON THE FINAL PRODUCT

    Directory of Open Access Journals (Sweden)

    V. V. Klubovich

    2016-01-01

    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.

  13. Diffuse-charge effects on the transient response of electrochemical cells

    NARCIS (Netherlands)

    Soestbergen, M.; Biesheuvel, P.M.; Bazant, M.Z.

    2010-01-01

    We present theoretical models for the time-dependent voltage of an electrochemical cell in response to a current step, including effects of diffuse charge (or “space charge”) near the electrodes on Faradaic reaction kinetics. The full model is based on the classical Poisson-Nernst-Planck equations

  14. Effects of complexation of oppositely charged water-soluble cobaltphthalocyanines on catalytic mercaptoethanol autoxidation

    NARCIS (Netherlands)

    Schipper, E.T.W.M.; Heuts, J.P.A.; Piet, P.; Beelen, T.P.M.; German, A.L.

    1994-01-01

    In order to elucidate the different promoting effects polycations have on cobalt(II) phthalocyanine-catalyzed autoxidn. of 2-mercaptoethanol, the properties of mixts. of oppositely charged water-sol. cobalt(II) phthalocyanines were studied. The contribution of polycation-induced dimerization of the

  15. Monolithic junction field-effect transistor charge preamplifier for calorimetry at high luminosity hadron colliders

    International Nuclear Information System (INIS)

    Radeka, V.; Rescia, S.; Rehn, L.A.; Manfredi, P.F.; Speziali, V.

    1991-11-01

    The outstanding noise and radiation hardness characteristics of epitaxial-channel junction field-effect transistors (JFET) suggest that a monolithic preamplifier based upon them may be able to meet the strict specifications for calorimetry at high luminosity colliders. Results obtained so far with a buried layer planar technology, among them an entire monolithic charge-sensitive preamplifier, are described

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

    International Nuclear Information System (INIS)

    Correa, M.M.

    1989-10-01

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

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

    KAUST Repository

    Himmelberger, Scott; Dacuñ a, Javier; Rivnay, Jonathan; Jimison, Leslie H.; McCarthy-Ward, Thomas; Heeney, Martin; McCulloch, Iain; Toney, Michael F.; Salleo, Alberto

    2012-01-01

    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.

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

    KAUST Repository

    Himmelberger, Scott

    2012-11-23

    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.

  19. Full inelastic cross section, effective stopping and ranges of fast multiply charged ions

    International Nuclear Information System (INIS)

    Alimov, R.A.; Arslanbekov, T.U.; Matveev, B.I.; Rakhmatov, A.S.

    1994-01-01

    Inelastic processes taking place in collision of fast multiply charged ions with atoms are considered on the base of mechanism of sudden momentum transfer. The simple estimations are proposed of full inelastic cross sections, effective stopping and ion ranges in gaseous medium. (author). 10 refs

  20. Effects of hadronic colour structure in quasi-elastic and charge-exchange scattering on nuclei

    International Nuclear Information System (INIS)

    Kopeliovich, B.Z.; Zakharov, B.G.

    1986-01-01

    Effects of hadronic hidden colour screening are considered in hadron-nucleus interaction. It is shown that in the quasi-free charge exchange-reaction nuclear matter becomes transparent for the scattered hadron if the momentum transfer is large enough. The available experimental data confirm this prediction of QCD