Energy consumption and cost analysis of hybrid electric powertrain configurations for two wheelers

International Nuclear Information System (INIS)

Walker, Paul D.; Roser, Holger M.

2015-01-01

Highlights: • We analyse several driving cycles to for the preliminary design of hybrid two wheelers. • Simulation of alternate configurations to compare achievable driving range and economy. • Demonstrate that pure electric vehicles provide cost benefits over the vehicle life. • Hybrid and plug-in hybrid two wheelers have comparable costs to conventional vehicles. - Abstract: The development of hybrid electric two wheelers in recent years has targeted the reduction of on road emissions produced by these vehicles. However, added cost and complexity have resulted in the failure of these systems to meet consumer expectations. This paper presents a comparative study of the energy economy and essential costs of alternative forms of small two wheelers such as scooters or low capacity motorcycles. This includes conventional, hybrid, plug-in hybrid and electric variants. Through simulations of vehicle driving range using two popular driving cycles it is demonstrated that there is considerable benefit in fuel economy realised by hybridising such vehicles. However, the added costs associated with electrification, i.e. motor/generator, power electronics, and energy storage provide a significant cost obstacle to the purchase of such vehicles. Only the pure electric configuration is demonstrated to be cost effective over its life in comparison to conventional two wheelers. Both the hybrid electric and plug-in equivalents must overcome significant upfront costs to be cost competitive with conventional vehicles. This is demonstrated to be achieved if the annual driving range of the vehicle is increased substantially from the assumed mean. Given the shorter distances travelled by most two wheeler drivers it can therefore be concluded that the development of similar hybrid electric vehicles are unlikely to achieve the desired acceptance that pure electric or conventional equivalents currently achieve

Two-dimensional Semiconductor-Superconductor Hybrids

DEFF Research Database (Denmark)

Suominen, Henri Juhani

This thesis investigates hybrid two-dimensional semiconductor-superconductor (Sm-S) devices and presents a new material platform exhibiting intimate Sm-S coupling straight out of the box. Starting with the conventional approach, we investigate coupling superconductors to buried quantum well....... To overcome these issues we integrate the superconductor directly into the semiconducting material growth stack, depositing it in-situ in a molecular beam epitaxy system under high vacuum. We present a number of experiments on these hybrid heterostructures, demonstrating near unity interface transparency...

25th anniversary article: hybrid nanostructures based on two-dimensional nanomaterials.

Science.gov (United States)

Huang, Xiao; Tan, Chaoliang; Yin, Zongyou; Zhang, Hua

2014-04-09

Two-dimensional (2D) nanomaterials, such as graphene and transition metal dichalcogenides (TMDs), receive a lot of attention, because of their intriguing properties and wide applications in catalysis, energy-storage devices, electronics, optoelectronics, and so on. To further enhance the performance of their application, these 2D nanomaterials are hybridized with other functional nanostructures. In this review, the latest studies of 2D nanomaterial-based hybrid nanostructures are discussed, focusing on their preparation methods, properties, and applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Vapor Compressor Driven Hybrid Two-Phase Loop, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project will demonstrate a vapor compressor driven hybrid two-phase loop technology. The hybrid two-phase loop...

Two electron Rydberg states

International Nuclear Information System (INIS)

Cooke, W.E.

1981-01-01

This paper addresses the study of two-electron Rydberg atoms. With Multichannel Quantum Defect Theory (MQDT), there is a technique for characterizing a spectra in terms of a small number of parameters. A survey of some important effects specific to two-electon Rydberg states, using primarily the alkaline earth atoms for examples, is made. The remainder of the paper deals with a discussion of the electron-electron interaction, including some of the basic points of MQDT. Energy exchange between two electrons is also addressed

Two-Electron Transfer Pathways.

Science.gov (United States)

Lin, Jiaxing; Balamurugan, D; Zhang, Peng; Skourtis, Spiros S; Beratan, David N

2015-06-18

The frontiers of electron-transfer chemistry demand that we develop theoretical frameworks to describe the delivery of multiple electrons, atoms, and ions in molecular systems. When electrons move over long distances through high barriers, where the probability for thermal population of oxidized or reduced bridge-localized states is very small, the electrons will tunnel from the donor (D) to acceptor (A), facilitated by bridge-mediated superexchange interactions. If the stable donor and acceptor redox states on D and A differ by two electrons, it is possible that the electrons will propagate coherently from D to A. While structure-function relations for single-electron superexchange in molecules are well established, strategies to manipulate the coherent flow of multiple electrons are largely unknown. In contrast to one-electron superexchange, two-electron superexchange involves both one- and two-electron virtual intermediate states, the number of virtual intermediates increases very rapidly with system size, and multiple classes of pathways interfere with one another. In the study described here, we developed simple superexchange models for two-electron transfer. We explored how the bridge structure and energetics influence multielectron superexchange, and we compared two-electron superexchange interactions to single-electron superexchange. Multielectron superexchange introduces interference between singly and doubly oxidized (or reduced) bridge virtual states, so that even simple linear donor-bridge-acceptor systems have pathway topologies that resemble those seen for one-electron superexchange through bridges with multiple parallel pathways. The simple model systems studied here exhibit a richness that is amenable to experimental exploration by manipulating the multiple pathways, pathway crosstalk, and changes in the number of donor and acceptor species. The features that emerge from these studies may assist in developing new strategies to deliver multiple

ATLAS proton-proton event containing two electrons and two muons

CERN Multimedia

ATLAS Collaboration

2011-01-01

An event with two identified muons and two identified electrons from a proton- proton collision in ATLAS. This event is consistent with coming from two Z particles decaying: one Z decays to two muons, the other to two electrons. Such events are produced by Standard Model processes without Higgs particles. They are also a possible signature for Higgs particle production, but many events must be analysed together in order to tell if there is a Higgs signal. The two muons are picked out as red tracks penetrating right through the detector. The two electrons are picked out as green tracks in the central, inner detector, matching narrow green clusters of energy in the barrel part of the calorimeters. The inset at the bottom right shows a map of the energy seen in the detector: the two big yellow spikes correspond to the two electrons.

Focusing effects by one and two Coulomb centers in the autoionization of He

Energy Technology Data Exchange (ETDEWEB)

MartInez, S; Otranto, S [CONICET and Dto. de Fisica, Universidad Nacional del Sur, 8000 Bahia Blanca (Argentina); Suarez, S; Garibotti, C R, E-mail: smartine@criba.edu.a, E-mail: sotranto@uns.edu.a [CONICET and Centro Atomico Bariloche, 8400 S. C. de Bariloche (Argentina)

2009-11-01

In this work we consider the autoionization of He following double electron capture in He{sup 2+} + H{sub 2} collisions at an impact energy of 14 keV/amu. The post-collisional interaction with the two Coulomb centers is treated within the Barrachina-Macek model by employing the {Phi}{sub 2} correlated wave function introduced by Gasaneo et al to represent the continuum of the emitted electron in the field of two Coulomb centers. We compare the angular profiles in the electron spectrum with those obtained following double electron capture for the collision system He{sup 2+}+ He. Clear differences are observed in the spectra obtained for the atomic and molecular targets.

Variational and robust density fitting of four-center two-electron integrals in local metrics

Science.gov (United States)

Reine, Simen; Tellgren, Erik; Krapp, Andreas; Kjærgaard, Thomas; Helgaker, Trygve; Jansik, Branislav; Høst, Stinne; Salek, Paweł

2008-09-01

Density fitting is an important method for speeding up quantum-chemical calculations. Linear-scaling developments in Hartree-Fock and density-functional theories have highlighted the need for linear-scaling density-fitting schemes. In this paper, we present a robust variational density-fitting scheme that allows for solving the fitting equations in local metrics instead of the traditional Coulomb metric, as required for linear scaling. Results of fitting four-center two-electron integrals in the overlap and the attenuated Gaussian damped Coulomb metric are presented, and we conclude that density fitting can be performed in local metrics at little loss of chemical accuracy. We further propose to use this theory in linear-scaling density-fitting developments.

Heterogeneous electron transfer of a two-centered heme protein: redox and electrocatalytic properties of surface-immobilized cytochrome C(4).

Science.gov (United States)

Monari, Stefano; Battistuzzi, Gianantonio; Borsari, Marco; Di Rocco, Giulia; Martini, Laura; Ranieri, Antonio; Sola, Marco

2009-10-15

The recombinant diheme cytochrome c(4) from the psycrophilic bacterium Pseudoalteromonas haloplanktis TAC 125 and its Met64Ala and Met164Ala variants, which feature a hydroxide ion axially bound to the heme iron at the N- and C-terminal domains, respectively, were found to exchange electrons efficiently with a gold electrode coated with a SAM of 11-mercapto-1-undecanoic acid. The mutation-induced removal of the redox equivalence of the two heme groups and changes in the net charge of the protein lobes yield two-centered protein systems with unprecedented properties in the electrode-immobilized state. The heterogeneous and intraheme electron transfer processes were characterized for these species in which the high- and low-potential heme groups are swapped over in the bilobal protein framework and experience a constrained (M64A) and unconstrained (M164A) orientation toward the electrode. The reduction thermodynamics for the native and mutated hemes were measured for the first time for a diheme cytochrome c. In the diffusing regime, they reproduce closely those for the corresponding centers in single-heme class-I cytochromes c, despite the low sequence identity. Larger differences are observed in the thermodynamics of the immobilized species and in the heterogeneous electron transfer rate constants. T-dependent kinetic measurements show that the proteins are positioned approximately 7 A from the HOOC-terminated SAM-coated electrode. Protein-electrode orientation and efficient intraheme ET enable the His,OH(-)-ligated heme A of the immobilized Met64Ala variant to carry out the reductive electrocatalysis of molecular oxygen. This system therefore constitutes a novel two-centered heme-based biocatalytic interface to be exploited for "third-generation" amperometric biosensing.

New hybrid lead iodides: From one-dimensional chain to two-dimensional layered perovskite structure

International Nuclear Information System (INIS)

Xiong, Kecai; Liu, Wei; Teat, Simon J.; An, Litao; Wang, Hao; Emge, Thomas J.; Li, Jing

2015-01-01

Two new hybrid lead halides (H 2 BDA)[PbI 4 ] (1) (H 2 BDA=1,4-butanediammonium dication) and (HNPEIM)[PbI 3 ] (2) (HNPEIM=N-​phenyl-ethanimidamidine cation) have been synthesized and structurally characterized. X-ray diffraction analyses reveal that compound 1 features a two-dimensional corner-sharing perovskite layer whereas compound 2 contains one-dimensional edge-sharing double chains. The N-​phenyl-ethanimidamidine cation within compound 2 was generated in-situ under solvothermal conditions. The optical absorption spectra collected at room temperature suggest that both compounds are semiconductors having direct band gaps, with estimated values of 2.64 and 2.73 eV for 1 and 2, respectively. Results from the density functional theory (DFT) calculations are consistent with the experimental data. Density of states (DOS) analysis reveals that in both compounds 1 and 2, the energy states in the valence band maximum region are iodine 5p atomic orbitals with a small contribution from lead 6s, while in the region of conduction band minimum, the major contributions are from the inorganic (Pb 6p atomic orbitals) and organic components (C and N 2p atomic orbitals) in compound 1 and 2, respectively. - Graphical abstract: Two new hybrid lead halides built on one-dimensional edge-sharing double chains and two-dimensional corner-sharing perovskite layers are synthesized and their structural and electronic properties are analyzed. - Highlights: • Two new hybrid lead iodides are designed, synthesized, and characterized. • They are closely related to, but different from, perovskite structures. • The electronic properties of both compounds are analyzed by DFT calculations

New hybrid lead iodides: From one-dimensional chain to two-dimensional layered perovskite structure

Energy Technology Data Exchange (ETDEWEB)

Xiong, Kecai; Liu, Wei [Department of Chemistry and Chemical Biology, Rutgers University, 610 Taylor Road, Piscataway, NJ 08854 (United States); Teat, Simon J. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); An, Litao; Wang, Hao; Emge, Thomas J. [Department of Chemistry and Chemical Biology, Rutgers University, 610 Taylor Road, Piscataway, NJ 08854 (United States); Li, Jing, E-mail: jingli@rutgers.edu [Department of Chemistry and Chemical Biology, Rutgers University, 610 Taylor Road, Piscataway, NJ 08854 (United States)

2015-10-15

Two new hybrid lead halides (H{sub 2}BDA)[PbI{sub 4}] (1) (H{sub 2}BDA=1,4-butanediammonium dication) and (HNPEIM)[PbI{sub 3}] (2) (HNPEIM=N-​phenyl-ethanimidamidine cation) have been synthesized and structurally characterized. X-ray diffraction analyses reveal that compound 1 features a two-dimensional corner-sharing perovskite layer whereas compound 2 contains one-dimensional edge-sharing double chains. The N-​phenyl-ethanimidamidine cation within compound 2 was generated in-situ under solvothermal conditions. The optical absorption spectra collected at room temperature suggest that both compounds are semiconductors having direct band gaps, with estimated values of 2.64 and 2.73 eV for 1 and 2, respectively. Results from the density functional theory (DFT) calculations are consistent with the experimental data. Density of states (DOS) analysis reveals that in both compounds 1 and 2, the energy states in the valence band maximum region are iodine 5p atomic orbitals with a small contribution from lead 6s, while in the region of conduction band minimum, the major contributions are from the inorganic (Pb 6p atomic orbitals) and organic components (C and N 2p atomic orbitals) in compound 1 and 2, respectively. - Graphical abstract: Two new hybrid lead halides built on one-dimensional edge-sharing double chains and two-dimensional corner-sharing perovskite layers are synthesized and their structural and electronic properties are analyzed. - Highlights: • Two new hybrid lead iodides are designed, synthesized, and characterized. • They are closely related to, but different from, perovskite structures. • The electronic properties of both compounds are analyzed by DFT calculations.

Differential cross sections for the one electron two center symmetric systems

International Nuclear Information System (INIS)

Maidagan, J.M.; Piacentini, R.D.; Rivarola, R.D.; Universidad Autonoma de Madrid

1982-01-01

We use the two-state atomic expansion with variable nuclear charge to study charge-exchange differential cross sections for symmetrical one-electron systems at intermediate energy. The nonclassical small angle diffraction scattering is discussed. Our results are compared with data for H + -H collisions. (orig.)

Differential cross sections for the one electron two center symmetric systems

Energy Technology Data Exchange (ETDEWEB)

Maidagan, J.M.; Piacentini, R.D. (Universidad Nacional de Rosario (Argentina). Dept. de Fisica); Rivarola, R.D. (Bordeaux-1 Univ., 33 - Talence (France). Lab. d' Astrophysique; Universidad Autonoma de Madrid (Spain). Dept. de Quimica Fisica y Quimica Cuantica)

1982-03-01

We use the two-state atomic expansion with variable nuclear charge to study charge-exchange differential cross sections for symmetrical one-electron systems at intermediate energy. The nonclassical small angle diffraction scattering is discussed. Our results are compared with data for H/sup +/-H collisions.

Two-stream instabilities from the lower-hybrid frequency to the electron cyclotron frequency: application to the front of quasi-perpendicular shocks

Directory of Open Access Journals (Sweden)

L. Muschietti

2017-09-01

Full Text Available Quasi-perpendicular supercritical shocks are characterized by the presence of a magnetic foot due to the accumulation of a fraction of the incoming ions that is reflected by the shock front. There, three different plasma populations coexist (incoming ion core, reflected ion beam, electrons and can excite various two-stream instabilities (TSIs owing to their relative drifts. These instabilities represent local sources of turbulence with a wide frequency range extending from the lower hybrid to the electron cyclotron. Their linear features are analyzed by means of both a dispersion study and numerical PIC simulations. Three main types of TSI and correspondingly excited waves are identified: i. Oblique whistlers due to the (so-called fast relative drift between reflected ions/electrons; the waves propagate toward upstream away from the shock front at a strongly oblique angle (θ ∼ 50° to the ambient magnetic field Bo, have frequencies a few times the lower hybrid, and have wavelengths a fraction of the ion inertia length c∕ωpi. ii. Quasi-perpendicular whistlers due to the (so-called slow relative drift between incoming ions/electrons; the waves propagate toward the shock ramp at an angle θ a few degrees off 90°, have frequencies around the lower hybrid, and have wavelengths several times the electron inertia length c∕ωpe. iii. Extended Bernstein waves which also propagate in the quasi-perpendicular domain, yet are due to the (so-called fast relative drift between reflected ions/electrons; the instability is an extension of the electron cyclotron drift instability (normally strictly perpendicular and electrostatic and produces waves with a magnetic component which have frequencies close to the electron cyclotron as well as wavelengths close to the electron gyroradius and which propagate toward upstream. Present results are compared with previous works in order to stress some features not previously analyzed and to define a more

The plus-hybrid effect on the grain yield of two ZP maize hybrids

Directory of Open Access Journals (Sweden)

Božinović Sofija

2010-01-01

Full Text Available The combined effect of cytoplasmic male sterility and xenia on maize hybrid traits is referred to as the plus-hybrid effect. Two studied ZP hybrids differently responded to this effect for grain yield. All plus-hybrid combinations of the firstly observed hybrid had a higher yield than their fertile counterparts, but not significantly, while only one combination of the second hybrid positively responded, also without statistical significance. It seems that the observed effect mostly depended on the genotype of the female component.

Evidence of hybridization between two species of Melipona bees

Directory of Open Access Journals (Sweden)

Nascimento Vania Alves

2000-01-01

Full Text Available This report describes a case of hybridization between two species of Meliponinae bees (Melipona scutellaris from the Diamantina plateau in the State of Bahia, and Melipona capixaba from around Domingos Martins, in the State of Espírito Santo, Brazil. To demonstrate hybridization, electrophoretic profiles of esterase activity from three colonies were studied. Ten adult workers of M. scutellaris, M. capixaba and the hybrid colony were collected and processed individually. The pattern of esterase activity was constant for each species but differed between them, whereas hybrid bees had a pattern derived from both species. The fact that two ecologically different species of stingless bees separated by more than 300 km could still cross when placed in the same area suggests that there has not been any pressure to develop reproductive isolation.

Spin injection into a two-dimensional electron gas using inter-digital-ferromagnetic contacts

DEFF Research Database (Denmark)

Hu, C.M.; Nitta, J.; Jensen, Ane

2002-01-01

We present a model that describes the spin injection across a single interface with two electrodes. The spin-injection rate across a typical hybrid junction made of ferromagnet (FM) and a two-dimensional electron gas (2DEG) is found at the percentage level. We perforin spin-injection-detection ex......-injection-detection experiment on devices with two ferromagnetic contacts on a 2DEG confined in an InAs quantum well. A spin-injection rate of 4.5% is estimated from the measured magnetoresistance....

Hybrid synchronization of two independent chaotic systems on ...

Indian Academy of Sciences (India)

The real network nodes are always interfered by other messages. So, how to realize the hybrid synchronization of two independent chaotic systems based on the complex network is very important. To solve this problem, two other problems should be considered. One is how the same network node of the complex network ...

Distilling two-center-interference information during tunneling of aligned molecules with orthogonally polarized two-color laser fields

Science.gov (United States)

Gao, F.; Chen, Y. J.; Xin, G. G.; Liu, J.; Fu, L. B.

2017-12-01

When electrons tunnel through a barrier formed by the strong laser field and the two-center potential of a diatomic molecule, a double-slit-like interference can occur. However, this interference effect can not be probed directly right now, as it is strongly coupled with other dynamical processes during tunneling. Here, we show numerically and analytically that orthogonally polarized two-color (OTC) laser fields are capable of resolving the interference effect in tunneling, while leaving clear footprints of this effect in photoelectron momentum distributions. Moreover, this effect can be manipulated by changing the relative field strength of OTC fields.

Simulation study of two-ion hybrid resonance heating

International Nuclear Information System (INIS)

Riyopoulos, S.; Tajima, T.

1986-02-01

A one-dimensional low-noise, low-frequency electromagnetic particle simulation code that is appropriate for investigation of ion cyclotron resonance heating (ICRH) is developed. Retaining the hyperbolicity of the electromagnetic waves and exploiting nearly one-dimensional characteristics (perpendicular to the external magnetic field) of the ICRH, we use the guiding center electron approximation for the transverse electronic current calculation. We observe mode conversion of the incoming magnetosonic wave into the electrostatic ion-ion hybrid mode accompanied by strong ion-heating. The dependence of this heating on the different plasma parameters is examined through a series of simulations, focusing mainly on wave incidence from the high field side. Because K/sub parallel/ = 0 in our runs, the conventional Landau damping cannot explain the ion heating. Non-linear mechanisms for energy transfer are discussed. Our numerical results demonstrate the importance of the non-linear wave particle interaction for energy transfer are discussed. Our numerical results demonstrate the importance of the non-linear wave particle interaction for energy absorption during radio frequency heating in the ion cyclotron regime. 32 refs., 17 figs

Hybrid synchronization of two independent chaotic systems on ...

Indian Academy of Sciences (India)

Keywords. Hybrid synchronization; complex network; information source; chaotic system. ... encryption and decryption through synchronization. However, the ... Certainly, if the two systems are different, the security would be improved. How.

Design of hybrid two-dimensional and three-dimensional nanostructured arrays for electronic and sensing applications

Science.gov (United States)

Ko, Hyunhyub

This dissertation presents the design of organic/inorganic hybrid 2D and 3D nanostructured arrays via controlled assembly of nanoscale building blocks. Two representative nanoscale building blocks such as carbon nanotubes (one-dimension) and metal nanoparticles (zero-dimension) are the core materials for the study of solution-based assembly of nanostructured arrays. The electrical, mechanical, and optical properties of the assembled nanostructure arrays have been investigated for future device applications. We successfully demonstrated the prospective use of assembled nanostructure arrays for electronic and sensing applications by designing flexible carbon nanotube nanomembranes as mechanical sensors, highly-oriented carbon nanotubes arrays for thin-film transistors, and gold nanoparticle arrays for SERS chemical sensors. In first section, we fabricated highly ordered carbon nanotube (CNT) arrays by tilted drop-casting or dip-coating of CNT solution on silicon substrates functionalized with micropatterned self-assembled monolayers. We further exploited the electronic performance of thin-film transistors based on highly-oriented, densely packed CNT micropatterns and showed that the carrier mobility is largely improved compared to randomly oriented CNTs. The prospective use of Raman-active CNTs for potential mechanical sensors has been investigated by studying the mechano-optical properties of flexible carbon nanotube nanomembranes, which contain freely-suspended carbon nanotube array encapsulated into ultrathin (optical waveguide properties of nano-canals. We demonstrated the ability of this SERS substrate for trace level sensing of nitroaromatic explosives by detecting down to 100 zeptogram (˜330 molecules) of DNT.

A theory of two-stream instability in two hollow relativistic electron beams

International Nuclear Information System (INIS)

Uhm, H.S.

1993-01-01

Stability properties of two-stream instability of two hollow electron beams are investigated. The equilibrium configuration consists of two intense relativistic hollow electron beams propagating through a grounded conducting cylinder. Analysis of the longitudinal two-stream instability is carried out within the framework of the linearized Vlasov--Maxwell equations for the equilibrium distribution function, in which beam electrons have a Lorentzian distribution in the axial momentum. Dispersion relation of the longitudinal two-stream instability is derived. Stability criteria from this dispersion relation indicate that the normalized velocity difference Δβ between the beams should be within a certain range of value to be unstable. Growth rate of the instability is a substantial fraction of the real frequency, thereby indicating that the longitudinal two-stream instability is an effective means of beam current modulation. Transverse instability of hollow electron beams is also investigated. Dispersion relation of the coupled transverse oscillation of the beams is derived and numerical investigation of this dispersion relation is carried out. Growth rate of the kink instability is a substantial fraction of the diocotron frequency, which may pose a serious threat to the two-stream klystron

Tuning spin transport across two-dimensional organometallic junctions

Science.gov (United States)

Liu, Shuanglong; Wang, Yun-Peng; Li, Xiangguo; Fry, James N.; Cheng, Hai-Ping

2018-01-01

We study via first-principles modeling and simulation two-dimensional spintronic junctions made of metal-organic frameworks consisting of two Mn-phthalocyanine ferromagnetic metal leads and semiconducting Ni-phthalocyanine channels of various lengths. These systems exhibit a large tunneling magnetoresistance ratio; the transmission functions of such junctions can be tuned using gate voltage by three orders of magnitude. We find that the origin of this drastic change lies in the orbital alignment and hybridization between the leads and the center electronic states. With physical insight into the observed on-off phenomenon, we predict a gate-controlled spin current switch based on two-dimensional crystallines and offer general guidelines for designing spin junctions using 2D materials.

Performance of an Orifice Compensated Two-Lobe Hole-Entry Hybrid Journal Bearing

Directory of Open Access Journals (Sweden)

J. Sharana Basavaraja

2008-01-01

Full Text Available The work presented in this paper aims to study the performance of a two-lobe hole-entry hybrid journal bearing system compensated by orifice restrictors. The Reynolds equation governing the flow of lubricant in the clearance space between the journal and bearing together with the equation of flow through an orifice restrictor has been solved using FEM and Galerkin's method. The bearing performance characteristics results have been simulated for an orifice compensated nonrecessed two-lobe hole-entry hybrid journal bearing symmetric configuration for the various values of offset factor (, restrictor design parameter (2, and the value of external load (0. Further, a comparative study of the performance of a two-lobe hole-entry hybrid journal bearing system with a circular hole-entry symmetric hybrid journal bearing system has also been carried out so that a designer has a better flexibility in choosing a suitable bearing configuration. The simulated numerical results indicate that for the two-lobe symmetric hole-entry hybrid journal bearing system with an offset factor ( greater than one provides 30 to 50 percent larger values of direct stiffness and direct damping coefficients as compared to a circular symmetric hole-entry hybrid journal bearing system.

Resonances in the two centers Coulomb system

International Nuclear Information System (INIS)

Seri, Marcello

2012-01-01

In this work we investigate the existence of resonances for two-centers Coulomb systems with arbitrary charges in two and three dimensions, defining them in terms of generalized complex eigenvalues of a non-selfadjoint deformation of the two-center Schroedinger operator. After giving a description of the bifurcation of the classical system for positive energies, we construct the resolvent kernel of the operators and we prove that they can be extended analytically to the second Riemann sheet. The resonances are then defined and studied with numerical methods and perturbation theory.

Resonances in the two centers Coulomb system

Energy Technology Data Exchange (ETDEWEB)

Seri, Marcello

2012-09-14

In this work we investigate the existence of resonances for two-centers Coulomb systems with arbitrary charges in two and three dimensions, defining them in terms of generalized complex eigenvalues of a non-selfadjoint deformation of the two-center Schroedinger operator. After giving a description of the bifurcation of the classical system for positive energies, we construct the resolvent kernel of the operators and we prove that they can be extended analytically to the second Riemann sheet. The resonances are then defined and studied with numerical methods and perturbation theory.

Dynamics in ion-molecule collisions at high velocities: One- and two-electron processes

International Nuclear Information System (INIS)

Wang, Yudong.

1992-01-01

This dissertation addresses the dynamic interactions in ion-molecule collisions. Theoretical methods are developed for single and multiple electron transitions in fast collisions with diatomic molecules by heavy-ion projectiles. Various theories and models are developed to treat the three basic inelastic processes (excitation, ionization and charge transfer) involving one and more electrons. The development, incorporating the understanding of ion-atom collision theories with some unique characteristics for molecular targets, provides new insights into phenomena that are absent from collisions with atomic targets. The influence from the multiple scattering centers on collision dynamics is assessed. For diatomic molecules, effects due to a fixed molecular orientation or alignment are calculated and compared with available experimental observations. Compared with excitation and ionization, electron capture, which probes deeper into the target, presents significant two-center interference and strong orientation dependence. Attention has been given in this dissertation to exploring mechanisms for two-and multiple electron transitions. Application of independent electron approximation to transfer excitation from molecular hydrogen is studied. Electron-electron interaction originated from projectile and target nuclear centers is studied in conjunction with the molecular nature of target. Limitations of the present theories and models as well as possible new areas for future theoretical and experimental applications are also discussed. This is the first attempt to describe multi-electron processes in molecular dynamics involving fast highly charged ions

Microstructure in two- and three-dimensional hybrid simulations of perpendicular collisionless shocks

Czech Academy of Sciences Publication Activity Database

Burgess, D.; Hellinger, Petr; Gingell, I.; Trávníček, Pavel M.

2016-01-01

Roč. 82, č. 4 (2016), 905820401/1-905820401/23 ISSN 0022-3778 Institutional support: RVO:68378289 Keywords : ion-acceleration * numerical simulations * bow shock * electron acceleration * cluster observations * self-reformation * magnetic-field * whistler waves * injection * nonstationarity Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.160, year: 2016 https://www.cambridge.org/core/ journals /journal-of-plasma-physics/article/microstructure-in-two-and-three-dimensional-hybrid-simulations-of-perpendicular-collisionless-shocks/F964EF89FB14A6504A49CFAD54970E2B

Design and initial operation of a two-color soft x-ray camera system on the Compact Toroidal Hybrid experiment

International Nuclear Information System (INIS)

Herfindal, J. L.; Dawson, J. D.; Ennis, D. A.; Hartwell, G. J.; Loch, S. D.; Maurer, D. A.

2014-01-01

A multi-camera soft x-ray diagnostic has been developed to measure the equilibrium electron temperature profile and temperature fluctuations due to magnetohydrodynamic activity on the Compact Toroidal Hybrid experiment. The diagnostic consists of three separate cameras each employing two 20-channel diode arrays that view the same plasma region through different beryllium filter thicknesses of 1.8 μm and 3.0 μm allowing electron temperature measurements between 50 eV and 200 eV. The Compact Toroidal Hybrid is a five-field period current-carrying stellarator, in which the presence of plasma current strongly modifies the rotational transform and degree of asymmetry of the equilibrium. Details of the soft x-ray emission, effects of plasma asymmetry, and impurity line radiation on the design and measurement of the two-color diagnostic are discussed. Preliminary estimates of the temperature perturbation due to sawtooth oscillations observed in these hybrid discharges are given

Regular perturbation theory for two-electron atoms

International Nuclear Information System (INIS)

Feranchuk, I.D.; Triguk, V.V.

2011-01-01

Regular perturbation theory (RPT) for the ground and excited states of two-electron atoms or ions is developed. It is shown for the first time that summation of the matrix elements from the electron-electron interaction operator over all intermediate states can be calculated in a closed form by means of the two-particle Coulomb Green's function constructed in the Letter. It is shown that the second order approximation of RPT includes the main part of the correlation energy both for the ground and excited states. This approach can be also useful for description of two-electron atoms in external fields. -- Highlights: → We develop regular perturbation theory for the two-electron atoms or ions. → We calculate the sum of the matrix elements over all intermediate states. → We construct the two-particle Coulomb Green's function.

CMS: Simulated Higgs to two jets and two electrons

CERN Multimedia

1997-01-01

This track is an example of simulated data modelled for the CMS detector on the Large Hadron Collider (LHC) at CERN, which will begin taking data in 2008. Here a Higgs boson is produced which decays into two jets of hadrons and two electrons. The lines represent the possible paths of particles produced by the proton-proton collision in the detector while the energy these particles deposit is shown in blue.

Atomically thin two-dimensional organic-inorganic hybrid perovskites

Science.gov (United States)

Dou, Letian; Wong, Andrew B.; Yu, Yi; Lai, Minliang; Kornienko, Nikolay; Eaton, Samuel W.; Fu, Anthony; Bischak, Connor G.; Ma, Jie; Ding, Tina; Ginsberg, Naomi S.; Wang, Lin-Wang; Alivisatos, A. Paul; Yang, Peidong

2015-09-01

Organic-inorganic hybrid perovskites, which have proved to be promising semiconductor materials for photovoltaic applications, have been made into atomically thin two-dimensional (2D) sheets. We report the solution-phase growth of single- and few-unit-cell-thick single-crystalline 2D hybrid perovskites of (C4H9NH3)2PbBr4 with well-defined square shape and large size. In contrast to other 2D materials, the hybrid perovskite sheets exhibit an unusual structural relaxation, and this structural change leads to a band gap shift as compared to the bulk crystal. The high-quality 2D crystals exhibit efficient photoluminescence, and color tuning could be achieved by changing sheet thickness as well as composition via the synthesis of related materials.

Hybridization of two major termite invaders as a consequence of human activity.

Science.gov (United States)

Chouvenc, Thomas; Helmick, Ericka E; Su, Nan-Yao

2015-01-01

While hybridization of an invasive species with a native species is a common occurrence, hybridization between two invasive species is rare. Formosan subterranean termites (Coptotermes formosanus) and Asian subterranean termites (C. gestroi) are both ecologically successful and are the two most economically important termite pests in the world. Both species have spread throughout many areas of the world due to human activity; however, their distributions overlap in only three narrow areas because of distinct ecological requirements. In south Florida, where C. formosanus and C. gestroi are both invasive, the dispersal flight seasons of both species overlapped for the first time on record in 2013 and 2014. Pairings of heterospecific individuals were readily observed in the field and C. gestroi males preferentially engaged in mating behavior with C. formosanus females rather than females from their own species. In the laboratory, heterospecific and conspecific pairings had an equal colony establishment rate, but heterospecific incipient colonies had twice the growth rate of conspecific incipient colonies, suggesting a potential case of hybrid vigor. As all pre-zygotic barriers were lifted between the two species in the field, the apparent absence of post-zygotic barriers in the laboratory raises the possibility for introgressive hybridization in south Florida. While laboratory observations remain to be confirmed in the field, and the alate hybrid fertility is currently unknown, our results raise a tangible concern about the hybridization of two major destructive pest species. Such hybridization would likely be associated with a new economic impact.

Stark shifting two-electron quantum dot

International Nuclear Information System (INIS)

Dineykhan, M.; Zhaugasheva, S.A.; Duysebaeva, K.S.

2003-01-01

Advances in modern technology make it possible to create semiconducting nano-structures (quantum dot) in which a finite number of electrons are 'captured' in a bounded volume. A quantum dot is associated with a quantum well formed at the interface, between two finite-size semiconductors owing to different positions of the forbidden gaps on the energy scale in these semiconductors. The possibility of monitoring and controlling the properties of quantum dots attracts considerable attention to these objects, as a new elemental basis for future generations of computers. The quantum-mechanical effects and image potential play a significant role in the description of the formation mechanism quantum dot, and determined the confinement potential in a two-electron quantum dot only for the spherical symmetric case. In the present talk, we considered the formation dynamics of two-electron quantum dot with violation of spherical symmetry. So, we have standard Stark potential. The energy spectrum two-electron quantum dot were calculated. Usually Stark interactions determined the tunneling phenomena between quantum dots

Covering and piercing disks with two centers

KAUST Repository

Ahn, Heekap; Kim, Sangsub; Knauer, Christian; Schlipf, Lena; Shin, Chansu; Vigneron, Antoine E.

2013-01-01

We give exact and approximation algorithms for two-center problems when the input is a set D of disks in the plane. We first study the problem of finding two smallest congruent disks such that each disk in D intersects one of these two disks. Then we study the problem of covering the set D by two smallest congruent disks. © 2012 Elsevier B.V.

Covering and piercing disks with two centers

KAUST Repository

Ahn, Heekap

2013-04-01

We give exact and approximation algorithms for two-center problems when the input is a set D of disks in the plane. We first study the problem of finding two smallest congruent disks such that each disk in D intersects one of these two disks. Then we study the problem of covering the set D by two smallest congruent disks. © 2012 Elsevier B.V.

Novel lithium titanate-graphene hybrid containing two graphene conductive frameworks for lithium-ion battery with excellent electrochemical performance

Energy Technology Data Exchange (ETDEWEB)

Ruiyi, Li; Tengyuan, Chen; Beibei, Sun [School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122 (China); Zaijun, Li [School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122 (China); Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, Wuxi 214122 (China); Zhiquo, Gu; Guangli, Wang; Junkang, Liu [School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122 (China)

2015-10-15

Graphical abstract: We developed a new Novel lithium titanate-graphene nanohybrid containing two graphene conductive frameworks. The unique architecture creates fast electron transfer and rapid mass transport of electrolyte. The hybrid electrode provides excellent electrochemical performances for lithium-ion batteries, including high specific capacity, outstanding rate capability and intriguing cycling stability. - Highlights: • We reported a new LTO-graphene nanohybrid containing two graphene conductive frameworks. • One graphene framework greatly improves the electrical conductivity of LTO crystal. • Another graphene framework enhances electrical conductivity of between LTO crystals and electrolyte transport. • The unique architecture creates big tap density, ultrafast electron transfer and rapid mass transport. • The hybrid electrode provides excellent electrochemical performance for lithium-ion batteries. - ABSTRACT: The paper reported the synthesis of lithium titanate(LTO)-graphene hybrid containing two graphene conductive frameworks (G@LTO@G). Tetrabutyl titanate and graphene were dispersed in tertbutanol and heated to reflux state by microwave irradiation. Followed by adding lithium acetate to produce LTO precursor/graphene (p-LTO/G). The resulting p-LTO/G offers homogeneous morphology and ultra small size. All graphene sheets were buried in the spherical agglomerates composed of primitive particles through the second agglomeration. The p-LTO/G was calcined to LTO@graphene (LTO@G). To obtain G@LTO@G, the LTO@G was further hybridized with graphene. The as-prepared G@LTO@G shows well-defined three-dimensional structure and hierarchical porous distribution. Its unique architecture creates big tap density, fast electron transfer and rapid electrolyte transport. As a result, the G@LTO@G provides high specific capacity (175.2 mA h g{sup −1} and 293.5 mA cm{sup −3}), outstanding rate capability (155.7 mAh g{sup −1} at 10C) and intriguing cycling

Ultrafast carrier thermalization in lead iodide perovskite probed with two-dimensional electronic spectroscopy.

Science.gov (United States)

Richter, Johannes M; Branchi, Federico; Valduga de Almeida Camargo, Franco; Zhao, Baodan; Friend, Richard H; Cerullo, Giulio; Deschler, Felix

2017-08-29

In band-like semiconductors, charge carriers form a thermal energy distribution rapidly after optical excitation. In hybrid perovskites, the cooling of such thermal carrier distributions occurs on timescales of about 300 fs via carrier-phonon scattering. However, the initial build-up of the thermal distribution proved difficult to resolve with pump-probe techniques due to the requirement of high resolution, both in time and pump energy. Here, we use two-dimensional electronic spectroscopy with sub-10 fs resolution to directly observe the carrier interactions that lead to a thermal carrier distribution. We find that thermalization occurs dominantly via carrier-carrier scattering under the investigated fluences and report the dependence of carrier scattering rates on excess energy and carrier density. We extract characteristic carrier thermalization times from below 10 to 85 fs. These values allow for mobilities of 500 cm 2  V -1  s -1 at carrier densities lower than 2 × 10 19  cm -3 and limit the time for carrier extraction in hot carrier solar cells.Carrier-carrier scattering rates determine the fundamental limits of carrier transport and electronic coherence. Using two-dimensional electronic spectroscopy with sub-10 fs resolution, Richter and Branchi et al. extract carrier thermalization times of 10 to 85 fs in hybrid perovskites.

Hybridization of two major termite invaders as a consequence of human activity.

Directory of Open Access Journals (Sweden)

Thomas Chouvenc

Full Text Available While hybridization of an invasive species with a native species is a common occurrence, hybridization between two invasive species is rare. Formosan subterranean termites (Coptotermes formosanus and Asian subterranean termites (C. gestroi are both ecologically successful and are the two most economically important termite pests in the world. Both species have spread throughout many areas of the world due to human activity; however, their distributions overlap in only three narrow areas because of distinct ecological requirements. In south Florida, where C. formosanus and C. gestroi are both invasive, the dispersal flight seasons of both species overlapped for the first time on record in 2013 and 2014. Pairings of heterospecific individuals were readily observed in the field and C. gestroi males preferentially engaged in mating behavior with C. formosanus females rather than females from their own species. In the laboratory, heterospecific and conspecific pairings had an equal colony establishment rate, but heterospecific incipient colonies had twice the growth rate of conspecific incipient colonies, suggesting a potential case of hybrid vigor. As all pre-zygotic barriers were lifted between the two species in the field, the apparent absence of post-zygotic barriers in the laboratory raises the possibility for introgressive hybridization in south Florida. While laboratory observations remain to be confirmed in the field, and the alate hybrid fertility is currently unknown, our results raise a tangible concern about the hybridization of two major destructive pest species. Such hybridization would likely be associated with a new economic impact.

Role of the recoil effect in two-center interference in X-ray photoionization

International Nuclear Information System (INIS)

Ueda, K.; Liu, X.-J.; Pruemper, G.; Lischke, T.; Tanaka, T.; Hoshino, M.; Tanaka, H.; Minkov, I.; Kimberg, V.; Gel'mukhanov, F.

2006-01-01

X-ray photoelectron spectra of the N 2 molecule are studied both experimentally and theoretically in the extended energy region up to 1 keV. The ratio of the photoionization cross sections for the gerade and ungerade core levels displays a modulation in the high energy region caused by the two-center interference, as predicted by Cohen and Fano (CF) in 1966. The physical background of this CF effect is the same as in Young's double-slit experiment. We have found that the interference pattern deviates significantly from the CF prediction. The origin of such a breakdown of the CF formula is the scattering of the photoelectron inside the molecule and the momentum transfer from the emitted fast photoelectron to the nuclei. Usually the recoil effect is small. We show that the electron recoil strongly affects the two-center interference pattern. Both stationary and dynamical aspects of the recoil effect shed light on the role of the momentum exchange in the two-center interference

UC Davis Fuel Cell, Hydrogen, and Hybrid Vehicle (FCH2V) GATE Center of Excellence

Energy Technology Data Exchange (ETDEWEB)

Erickson, Paul

2012-05-31

This is the final report of the UC Davis Fuel Cell, Hydrogen, and Hybrid Vehicle (FCH2V) GATE Center of Excellence which spanned from 2005-2012. The U.S. Department of Energy (DOE) established the Graduate Automotive Technology Education (GATE) Program, to provide a new generation of engineers and scientists with knowledge and skills to create advanced automotive technologies. The UC Davis Fuel Cell, Hydrogen, and Hybrid Vehicle (FCH2V) GATE Center of Excellence established in 2005 is focused on research, education, industrial collaboration and outreach within automotive technology. UC Davis has had two independent GATE centers with separate well-defined objectives and research programs from 1998. The Fuel Cell Center, administered by ITS-Davis, has focused on fuel cell technology. The Hybrid-Electric Vehicle Design Center (HEV Center), administered by the Department of Mechanical and Aeronautical Engineering, has focused on the development of plug-in hybrid technology using internal combustion engines. The merger of these two centers in 2005 has broadened the scope of research and lead to higher visibility of the activity. UC Davis's existing GATE centers have become the campus's research focal points on fuel cells and hybrid-electric vehicles, and the home for graduate students who are studying advanced automotive technologies. The centers have been highly successful in attracting, training, and placing top-notch students into fuel cell and hybrid programs in both industry and government.

Calculation of the two-electron Darwin term using explicitly correlated wave functions

International Nuclear Information System (INIS)

Middendorf, Nils; Höfener, Sebastian; Klopper, Wim; Helgaker, Trygve

2012-01-01

Graphical abstract: The two-electron Darwin term is computed analytically at the MP2-F12 level of theory using density fitted integrals. Highlights: ► Two-electron Darwin term computed analytically at the MP2-F12 level. ► Darwin two-electron integrals computed using density fitting techniques. ► Two-electron Darwin term dominated by singlet pair contributions. ► Much improved basis set convergence is achieved with F12 methods. ► Interference correction works well for the two-electron Darwin term. - Abstract: This article is concerned with the calculation of the two-electron Darwin term (D2). At the level of explicitly correlated second-order perturbation theory (MP2-F12), the D2 term is obtained as an analytic energy derivative; at the level of explicitly correlated coupled-cluster theory, it is obtained from finite differences. To avoid the calculation of four-center integrals, a density-fitting approximation is applied to the D2 two-electron integrals without loss of accuracy, even though the absolute value of the D2 term is typically about 0.1 mE h . Explicitly correlated methods provide a qualitatively correct description of the short-range region around the Coulomb hole, even for small orbital basis sets. Therefore, explicitly correlated wave functions remedy the otherwise extremely slow convergence of the D2 contribution with respect to the basis-set size, yielding more accurate results than those obtained by two-point basis-set extrapolation. Moreover, we show that the interference correction of Petersson’s complete-basis-set model chemistry can be used to compute a D2 basis-set correction at the MP2-F12 level to improve standard coupled-cluster singles-and-doubles results.

Covering and piercing disks with two centers

KAUST Repository

Ahn, Heekap; Kim, Sangsub; Knauer, Christian; Schlipf, Lena; Shin, Chansu; Vigneron, Antoine E.

2011-01-01

We consider new versions of the two-center problem where the input consists of a set D of disks in the plane. We first study the problem of finding two smallest congruent disks such that each disk in intersects one of these two disks. Then we study the problem of covering the set D by two smallest congruent disks. We give exact and approximation algorithms for these versions. © 2011 Springer-Verlag.

Graphene/MoS2 hybrid technology for large-scale two-dimensional electronics.

Science.gov (United States)

Yu, Lili; Lee, Yi-Hsien; Ling, Xi; Santos, Elton J G; Shin, Yong Cheol; Lin, Yuxuan; Dubey, Madan; Kaxiras, Efthimios; Kong, Jing; Wang, Han; Palacios, Tomás

2014-06-11

Two-dimensional (2D) materials have generated great interest in the past few years as a new toolbox for electronics. This family of materials includes, among others, metallic graphene, semiconducting transition metal dichalcogenides (such as MoS2), and insulating boron nitride. These materials and their heterostructures offer excellent mechanical flexibility, optical transparency, and favorable transport properties for realizing electronic, sensing, and optical systems on arbitrary surfaces. In this paper, we demonstrate a novel technology for constructing large-scale electronic systems based on graphene/molybdenum disulfide (MoS2) heterostructures grown by chemical vapor deposition. We have fabricated high-performance devices and circuits based on this heterostructure, where MoS2 is used as the transistor channel and graphene as contact electrodes and circuit interconnects. We provide a systematic comparison of the graphene/MoS2 heterojunction contact to more traditional MoS2-metal junctions, as well as a theoretical investigation, using density functional theory, of the origin of the Schottky barrier height. The tunability of the graphene work function with electrostatic doping significantly improves the ohmic contact to MoS2. These high-performance large-scale devices and circuits based on this 2D heterostructure pave the way for practical flexible transparent electronics.

Decentralised treatment of concentrated sewage at low temperature in a two-step anaerobic system: two upflow-hybrid septic tanks

NARCIS (Netherlands)

Elmitwally, T.A.; Sayed, S.; Groendijk, L.; Lier, van J.B.; Zeeman, G.; Lettinga, G.

2003-01-01

The decentralised treatment of concentrated sewage (about 3,600 mgCOD/1) at low temperature was investigated in a two-step anaerobic system: two-anaerobic hybrid (AH) septic tanks (each 0.575 m(3)). The two reactors were placed in a temperature controlled-room and the HRT was 2.5 days for each

Hybrid vigour and gene action for two quantitative traits of castor ...

African Journals Online (AJOL)

Five homozygous lines of castor plant, namely RS1-Om, RN1-Om, RTl-2m, RSl- Owm, and RNl- Omb, were crossed to raise F1, F2, BC1, and BC2 generations. The hybrids were tested for hybrid vigour for two metric traits, viz; number of pods per plant and seed yield per plant. Highly significant hybrid vigour was detected ...

Construction of gateway-compatible yeast two-hybrid vectors for ...

African Journals Online (AJOL)

USER

2010-03-01

Mar 1, 2010 ... vectors pBTM116GW and pVP16GW by introducing the gateway cassette ... Key words: Yeast two-hybrid, gateway cloning technology, protein interaction. .... cycling parameters were as follows: an initial denaturation step at.

Observation of electron plasma waves in plasma of two-temperature electrons

International Nuclear Information System (INIS)

Ikezawa, Shunjiro; Nakamura, Yoshiharu.

1981-01-01

Propagation of electron plasma waves in a large and unmagnetized plasma containing two Maxwellian distributions of electrons is studied experimentally. Two kinds of plasma sources which supply electrons of different temperature are used. The temperature ratio is about 3 and the density ratio of hot to cool electrons is varied from 0 to 0.5. A small contamination of hot electrons enhances the Landau damping of the principal mode known as the Bohm-Gross mode. When the density of hot electrons is larger than about 0.2, two modes are observed. The results agree with theoretical dispersion relations when excitation efficiencies of the modes are considered. (author)

Implementation and evaluation of change-over speed in plug-in hybrid electric two wheeler

International Nuclear Information System (INIS)

Amjad, Shaik; Rudramoorthy, R.; Sadagopan, P.; Neelakrishnan, S.

2016-01-01

In Asia, two wheelers are popular mode of transportation to a large group of people because of their relative affordability and ability to maneuver in heavy city traffic. However, the rate of fuel consumption and emission contribution by them, especially in urban areas need more attention to improve sustainability of energy and air quality. Recently, plug-in hybrid technology has been emerged as one of the most promising alternatives in reducing petroleum consumption and emission. This paper presents the implementation of plug-in hybrid technology on a two wheeler by formulation of novel control strategy suitable for Indian city driving needs. Experimental investigations on hub motor and IC (internal combustion) engine has been carried out to fix the change-over speed in hybrid mode, followed by road test on prototype vehicle. The performance of prototype vehicle on IDC (Indian driving cycle) simulated road pattern and actual road driving, confirmed the change-over speed of vehicle in hybrid mode. The converted plug-in hybrid electric two wheeler also demonstrated the drive strategy adopted for higher energy efficiency up to 2.5 times. So, plug-in hybrid electric two wheelers show significant improvements in fuel economy by replacing petroleum fuel with electricity for portions of trip to achieve nations' energy security. - Highlights: • Implementation of plug-in hybrid concept for two wheelers suitable for city driving. • Investigation on hub motor, engine and prototype vehicle to fix change-over speed. • Plug-in hybrid electric two wheeler demonstrates 2.48 times higher fuel efficiency. • Significant improvements in fuel economy help to achieve nations' energy security.

Enhanced coupling of the fast wave to electrons through mode conversion to the ion hybrid wave

International Nuclear Information System (INIS)

Lashmore-Davies, C.N.; Fuchs, V.; Ram, A.K.; Bers, A.

1996-07-01

The mode conversion of the fast compressional Alfven wave to the ion hybrid wave is analyzed with particular reference to a plasma with two ion species present in approximately equal proportions. Two configurations are considered, the first referring to the usual resonance-cut-off case and the second to a cut-off-resonance-cut-off situation. The optimum conditions for maximising the mode converted energy are given. The second order fast wave equation is generalised to include the effect of the parallel electric field. Hence, all ion and electron loss mechanisms for the fast wave are incorporated, including mode conversion at the two-ion hybrid resonance. The significance of the approximate equality of the two ion species concentrations is that the mode converted ion hybrid wave is damped only by the electrons. The damping of the ion hybrid wave is described with the aid of the local dispersion relation and by means of a toroidal ray tracing code. In particular, the ray tracing calculation shows that the mode converted energy is totally absorbed by the electrons close to the two-ion hybrid resonance. The generalised fast wave equation is solved to determine how much energy is lost from the fast wave, incident from the low field side, before it encounters the two-ion hybrid resonance. For comparable concentrations of the two ion species, the mode converted power can be separated from the power directly absorbed by the ions and electrons from the fast wave. This allows the conditions to be ascertained under which strong electron heating through mode conversion dominates the direct dissipation of the fast wave. (UK)

Natural variation for a hybrid incompatibility between two species of Mimulus.

Science.gov (United States)

Sweigart, Andrea L; Mason, Amanda R; Willis, John H

2007-01-01

Understanding the process by which hybrid incompatibility alleles become established in natural populations remains a major challenge to evolutionary biology. Previously, we discovered a two-locus Dobzhansky-Muller incompatibility that causes severe hybrid male sterility between two inbred lines of the incompletely isolated wildflower species, Mimulus guttatus and M. nasutus. An interspecific cross between these two inbred lines revealed that the M. guttatus (IM62) allele at hybrid male sterility 1 (hms1) acts dominantly in combination with recessive M. nasutus (SF5) alleles at hybrid male sterility 2 (hms2) to cause nearly complete hybrid male sterility. In this report, we extend these genetic analyses to investigate intraspecific variation for the hms1-hms2 incompatibility in natural populations of M. nasutus and M. guttatus, performing a series of interspecific crosses between individuals collected from a variety of geographic locales. Our results suggest that hms2 incompatibility alleles are common and geographically widespread within M. nasutus, but absent or rare in M. guttatus. In contrast, the hms1 locus is polymorphic within M. guttatus and the incompatibility allele appears to be extremely geographically restricted. We found evidence for the presence of the hms1 incompatibility allele in only two M. guttatus populations that exist within a few kilometers of each other. The restricted distribution of the hms1 incompatibility allele might currently limit the potential for the hms1-hms2 incompatibility to act as a species barrier between sympatric populations of M. guttatus and M. nasutus. Extensive sampling within a single M. guttatus population revealed that the hms1 locus is polymorphic and that the incompatibility allele appears to segregate at intermediate frequency, a pattern that is consistent with either genetic drift or natural selection.

Structure of herbivore communities in two oak (Quercus spp.) hybrid zones.

Science.gov (United States)

Boecklen, William J; Spellenberg, Richard

1990-11-01

We examined patterns of density and species diversity for leaf-mining Lepidopterans and gall-forming Hymenopterans in two oak (Quercus spp.) hybrid zones: Quercus depressipes x Q. rugosa and Q. emoryi x Q. coccolobifolia. In both species complexes, hybrid hosts typically supported significantly lower densities and species diversity of parasites than did parental types. This contradicts the findings of Whitham (1989) that suggested that hybrid hosts may act as parasite sinks both in ecological and evolutionary time. We discuss features of hybrid zones that are likely to influence patterns of herbivory.

Two-field axion-monodromy hybrid inflation model: Dante's Waterfall

Science.gov (United States)

Carone, Christopher D.; Erlich, Joshua; Sensharma, Anuraag; Wang, Zhen

2015-02-01

We describe a hybrid axion-monodromy inflation model motivated by the Dante's Inferno scenario. In Dante's Inferno, a two-field potential features a stable trench along which a linear combination of the two fields slowly rolls, rendering the dynamics essentially identical to that of single-field chaotic inflation. A shift symmetry allows for the Lyth bound to be effectively evaded as in other axion-monodromy models. In our proposal, the potential is concave downward near the origin and the inflaton trajectory is a gradual downward spiral, ending at a point where the trench becomes unstable. There, the fields begin falling rapidly towards the minimum of the potential and inflation terminates as in a hybrid model. We find parameter choices that reproduce observed features of the cosmic microwave background, and discuss our model in light of recent results from the BICEP2 and Planck experiments.

Electron acoustic solitary waves in unmagnetized two electron population dense plasmas

International Nuclear Information System (INIS)

Mahmood, S.; Masood, W.

2008-01-01

The electron acoustic solitary waves are studied in unmagnetized two population electron quantum plasmas. The quantum hydrodynamic model is employed with the Sagdeev potential approach to describe the arbitrary amplitude electron acoustic waves in a two electron population dense Fermi plasma. It is found that hot electron density hump structures are formed in the subsonic region in such type of quantum plasmas. The wave amplitude as well as the width of the soliton are increased with the increase of percentage presence of cold (thinly populated) electrons in a multicomponent quantum plasma. It is found that an increase in quantum diffraction parameter broadens the nonlinear structure. Furthermore, the amplitude of the nonlinear electron acoustic wave is found to increase with the decrease in Mach number. The numerical results are also presented to understand the formation of solitons in two electron population Fermi plasmas.

Measurement of the magnetic interaction between two bound electrons of two separate ions.

Science.gov (United States)

Kotler, Shlomi; Akerman, Nitzan; Navon, Nir; Glickman, Yinnon; Ozeri, Roee

2014-06-19

Electrons have an intrinsic, indivisible, magnetic dipole aligned with their internal angular momentum (spin). The magnetic interaction between two electronic spins can therefore impose a change in their orientation. Similar dipolar magnetic interactions exist between other spin systems and have been studied experimentally. Examples include the interaction between an electron and its nucleus and the interaction between several multi-electron spin complexes. The challenge in observing such interactions for two electrons is twofold. First, at the atomic scale, where the coupling is relatively large, it is often dominated by the much larger Coulomb exchange counterpart. Second, on scales that are substantially larger than the atomic, the magnetic coupling is very weak and can be well below the ambient magnetic noise. Here we report the measurement of the magnetic interaction between the two ground-state spin-1/2 valence electrons of two (88)Sr(+) ions, co-trapped in an electric Paul trap. We varied the ion separation, d, between 2.18 and 2.76 micrometres and measured the electrons' weak, millihertz-scale, magnetic interaction as a function of distance, in the presence of magnetic noise that was six orders of magnitude larger than the magnetic fields the electrons apply on each other. The cooperative spin dynamics was kept coherent for 15 seconds, during which spin entanglement was generated, as verified by a negative measured value of -0.16 for the swap entanglement witness. The sensitivity necessary for this measurement was provided by restricting the spin evolution to a decoherence-free subspace that is immune to collective magnetic field noise. Our measurements show a d(-3.0(4)) distance dependence for the coupling, consistent with the inverse-cube law.

Coherent Electron Focussing in a Two-Dimensional Electron Gas.

NARCIS (Netherlands)

Houten, H. van; Wees, B.J. van; Mooij, J.E.; Beenakker, C.W.J.; Williamson, J.G.; Foxon, C.T.

1988-01-01

The first experimental realization of ballistic point contacts in a two-dimensional electron gas for the study of transverse electron focussing by a magnetic field is reported. Multiple peaks associated with skipping orbits of electrons reflected specularly by the channel boundary are observed. At

Two-frequency operation of a hybrid TEA CO2 laser and its application to two-frequency pulse injection locking

International Nuclear Information System (INIS)

Sasaki, Koichi; Ohno, Hirotaka; Fujii, Takaharu; Tsukishima, Takashige.

1990-10-01

Simultaneous two-frequency oscillation of a hybrid TEA CO 2 laser is exhibited when the cw section is operated in a 'below threshold' state. The output of the hybrid laser thus obtained is injected into a main TEA CO 2 laser to obtain a power-modulated, long-pulse output with a well suppressed gain-switched spike. (author)

What Do We Know about Hybrid Regimes after Two Decades of Scholarship?

Directory of Open Access Journals (Sweden)

Mariam Mufti

2018-06-01

Full Text Available In two decades of scholarship on hybrid regimes two significant advancements have been made. First, scholars have emphasized that the hybrid regimes that emerged in the post-Cold War era should not be treated as diminished sub-types of democracy, and second, regime type is a multi-dimensional concept. This review essay further contends that losing the lexicon of hybridity and focusing on a single dimension of regime type—flawed electoral competition—has prevented an examination of extra-electoral factors that are necessary for understanding how regimes are differently hybrid, why there is such immense variation in the outcome of elections and why these regimes are constantly in flux. Therefore, a key recommendation emerging from this review of the scholarship is that to achieve a more thorough, multi-dimensional assessment of hybrid regimes, further research ought to be driven by nested research designs in which qualitative and quantitative approaches can be used to advance mid-range theory building.

Tight-binding model of the photosystem II reaction center: application to two-dimensional electronic spectroscopy

International Nuclear Information System (INIS)

Gelzinis, Andrius; Valkunas, Leonas; Abramavicius, Darius; Fuller, Franklin D; Ogilvie, Jennifer P; Mukamel, Shaul

2013-01-01

We propose an optimized tight-binding electron–hole model of the photosystem II (PSII) reaction center (RC). Our model incorporates two charge separation pathways and spatial correlations of both static disorder and fast fluctuations of energy levels. It captures the main experimental features observed in time-resolved two-dimensional (2D) optical spectra at 77 K: peak pattern, lineshapes and time traces. Analysis of 2D spectra kinetics reveals that specific regions of the 2D spectra of the PSII RC are sensitive to the charge transfer states. We find that the energy disorder of two peripheral chlorophylls is four times larger than the other RC pigments. (paper)

Two-stage free electron laser research

Science.gov (United States)

Segall, S. B.

1984-10-01

KMS Fusion, Inc. began studying the feasibility of two-stage free electron lasers for the Office of Naval Research in June, 1980. At that time, the two-stage FEL was only a concept that had been proposed by Luis Elias. The range of parameters over which such a laser could be successfully operated, attainable power output, and constraints on laser operation were not known. The primary reason for supporting this research at that time was that it had the potential for producing short-wavelength radiation using a relatively low voltage electron beam. One advantage of a low-voltage two-stage FEL would be that shielding requirements would be greatly reduced compared with single-stage short-wavelength FEL's. If the electron energy were kept below about 10 MeV, X-rays, generated by electrons striking the beam line wall, would not excite neutron resonance in atomic nuclei. These resonances cause the emission of neutrons with subsequent induced radioactivity. Therefore, above about 10 MeV, a meter or more of concrete shielding is required for the system, whereas below 10 MeV, a few millimeters of lead would be adequate.

Impurity with two electrons in the spherical quantum dot with Unite confinement potential

International Nuclear Information System (INIS)

Baghdasaryan, D A; Ghaltaghchyan, H Ts; Kazaryan, E M; Sarkisyan, H A

2016-01-01

Two-electron states in a spherical QD with the hydrogenic impurity located in the center and with a finite height confinement potential barrier are investigated. The effective mass mismatch have been taken into account. The dependence of ground state energy and Coulomb electron-electron interaction energy correction on the QD size is studied. The problem of the state exchange time control in QD is discussed, taking into account the spins of the electrons in the Russell-Saunders approximation. The effect of quantum emission has been shown. (paper)

Temperature dependent transport of two dimensional electrons in the integral quantum Hall regime

International Nuclear Information System (INIS)

Wi, H.P.

1986-01-01

This thesis is concerned with the temperature dependent electronic transport properties of a two dimensional electron gas subject to background potential fluctuations and a perpendicular magnetic field. The author carried out an extensive temperature dependent study of the transport coefficients, in the region of an integral quantum plateau, in an In/sub x/Ga/sub 1-x/As/InP heterostructure for 4.2K 10 cm -2 meV -1 ) even at the middle between two Landau levels, which is unexpected from model calculations based on short ranged randomness. In addition, the different T dependent behavior of rho/sub xx/ between the states in the tails and those near the center of a Landau level, indicates the existence of different electron states in a Landau level. Additionally, the author reports T-dependent transport measurements in the transition region between two quantum plateaus in several different materials

Angular correlation in the two-electron continuum

International Nuclear Information System (INIS)

Kheifets, A. S.; Bray, I.

2006-01-01

Following absorption of a single photon, angles of simultaneous emission of two electrons from a He(n 1 S) atom become more correlated with increasing n. We find that the strength of this correlation is due to the two-electron continuum of the electron-impact ionization of the He + (ns) ion. The strength is determined by the width of the momentum profile of the ionic ns state but not the strength of the electron correlation in the He initial state. This can explain the increasing (over He) angular correlation strength found in double photoionization of targets such as Be, Ne, and H 2

Genomic and environmental selection patterns in two distinct lettuce crop–wild hybrid crosses

Science.gov (United States)

Hartman, Yorike; Uwimana, Brigitte; Hooftman, Danny A P; Schranz, Michael E; van de Wiel, Clemens C M; Smulders, Marinus J M; Visser, Richard G F; van Tienderen, Peter H

2013-01-01

Genomic selection patterns and hybrid performance influence the chance that crop (trans)genes can spread to wild relatives. We measured fitness(-related) traits in two different field environments employing two different crop–wild crosses of lettuce. We performed quantitative trait loci (QTL) analyses and estimated the fitness distribution of early- and late-generation hybrids. We detected consistent results across field sites and crosses for a fitness QTL at linkage group 7, where a selective advantage was conferred by the wild allele. Two fitness QTL were detected on linkage group 5 and 6, which were unique to one of the crop–wild crosses. Average hybrid fitness was lower than the fitness of the wild parent, but several hybrid lineages outperformed the wild parent, especially in a novel habitat for the wild type. In early-generation hybrids, this may partly be due to heterosis effects, whereas in late-generation hybrids transgressive segregation played a major role. The study of genomic selection patterns can identify crop genomic regions under negative selection across multiple environments and cultivar–wild crosses that might be applicable in transgene mitigation strategies. At the same time, results were cultivar-specific, so that a case-by-case environmental risk assessment is still necessary, decreasing its general applicability. PMID:23789025

Genomic and environmental selection patterns in two distinct lettuce crop-wild hybrid crosses.

Science.gov (United States)

Hartman, Yorike; Uwimana, Brigitte; Hooftman, Danny A P; Schranz, Michael E; van de Wiel, Clemens C M; Smulders, Marinus J M; Visser, Richard G F; van Tienderen, Peter H

2013-06-01

Genomic selection patterns and hybrid performance influence the chance that crop (trans)genes can spread to wild relatives. We measured fitness(-related) traits in two different field environments employing two different crop-wild crosses of lettuce. We performed quantitative trait loci (QTL) analyses and estimated the fitness distribution of early- and late-generation hybrids. We detected consistent results across field sites and crosses for a fitness QTL at linkage group 7, where a selective advantage was conferred by the wild allele. Two fitness QTL were detected on linkage group 5 and 6, which were unique to one of the crop-wild crosses. Average hybrid fitness was lower than the fitness of the wild parent, but several hybrid lineages outperformed the wild parent, especially in a novel habitat for the wild type. In early-generation hybrids, this may partly be due to heterosis effects, whereas in late-generation hybrids transgressive segregation played a major role. The study of genomic selection patterns can identify crop genomic regions under negative selection across multiple environments and cultivar-wild crosses that might be applicable in transgene mitigation strategies. At the same time, results were cultivar-specific, so that a case-by-case environmental risk assessment is still necessary, decreasing its general applicability.

Hybrid fluorescence and electron cryo-microscopy for simultaneous electron and photon imaging.

Science.gov (United States)

Iijima, Hirofumi; Fukuda, Yoshiyuki; Arai, Yoshihiro; Terakawa, Susumu; Yamamoto, Naoki; Nagayama, Kuniaki

2014-01-01

Integration of fluorescence light and transmission electron microscopy into the same device would represent an important advance in correlative microscopy, which traditionally involves two separate microscopes for imaging. To achieve such integration, the primary technical challenge that must be solved regards how to arrange two objective lenses used for light and electron microscopy in such a manner that they can properly focus on a single specimen. To address this issue, both lateral displacement of the specimen between two lenses and specimen rotation have been proposed. Such movement of the specimen allows sequential collection of two kinds of microscopic images of a single target, but prevents simultaneous imaging. This shortcoming has been made up by using a simple optical device, a reflection mirror. Here, we present an approach toward the versatile integration of fluorescence and electron microscopy for simultaneous imaging. The potential of simultaneous hybrid microscopy was demonstrated by fluorescence and electron sequential imaging of a fluorescent protein expressed in cells and cathodoluminescence imaging of fluorescent beads. Copyright © 2013 Elsevier Inc. All rights reserved.

Natural occupation numbers in two-electron quantum rings.

Science.gov (United States)

Tognetti, Vincent; Loos, Pierre-François

2016-02-07

Natural orbitals (NOs) are central constituents for evaluating correlation energies through efficient approximations. Here, we report the closed-form expression of the NOs of two-electron quantum rings, which are prototypical finite-extension systems and new starting points for the development of exchange-correlation functionals in density functional theory. We also show that the natural occupation numbers for these two-electron paradigms are in general non-vanishing and follow the same power law decay as atomic and molecular two-electron systems.

Natural occupation numbers in two-electron quantum rings

Energy Technology Data Exchange (ETDEWEB)

Tognetti, Vincent, E-mail: vincent.tognetti@univ-rouen.fr [Normandy Univ., COBRA UMR 6014 & FR 3038, Université de Rouen, INSA Rouen, CNRS, 1 rue Tesniére, 76821 Mont Saint Aignan, Cedex (France); Loos, Pierre-François [Research School of Chemistry, Australian National University, Canberra ACT 2601 (Australia)

2016-02-07

Natural orbitals (NOs) are central constituents for evaluating correlation energies through efficient approximations. Here, we report the closed-form expression of the NOs of two-electron quantum rings, which are prototypical finite-extension systems and new starting points for the development of exchange-correlation functionals in density functional theory. We also show that the natural occupation numbers for these two-electron paradigms are in general non-vanishing and follow the same power law decay as atomic and molecular two-electron systems.

Two-dimensional MoS2-graphene hybrid nanosheets for high gravimetric and volumetric lithium storage

Science.gov (United States)

Deng, Yakai; Ding, Lixin; Liu, Qixing; Zhan, Liang; Wang, Yanli; Yang, Shubin

2018-04-01

Two-dimensional (2D) MoS2-graphene (MoS2-G) hybrid is fabricated simultaneously and scalablely with an efficient electrochemical exfoliation approach from the combined bulk MoS2-graphite wafer. The as-prepared 2D MoS2-G hybrid is tightly covered with each other with lateral sizes of 600 nm to few micrometers and can be directly assembled to flexible films for lithium storage. When used as anode material for lithium ion battery, the resultant MoS2-G hybrid film exhibits both high gravimetric (750 mA h g-1 at 50 mA g-1) and volumetric capacities (1200 mA h cm-3 at 0.1 mA cm-2). Such excellent electrochemical performance should attributed to the unique 2D structure and good conductive graphene network, which not only facilitates the diffusion of lithium ions, but also improves the fast transfer of electrons, satisfying the kinetics requirements for rapid lithium storage.

Two-fluid turbulence including electron inertia

Energy Technology Data Exchange (ETDEWEB)

Andrés, Nahuel, E-mail: nandres@iafe.uba.ar; Gómez, Daniel [Instituto de Astronomía y Física del Espacio, CC. 67, suc. 28, 1428 Buenos Aires (Argentina); Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón I, 1428 Buenos Aires (Argentina); Gonzalez, Carlos; Martin, Luis; Dmitruk, Pablo [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, 1428 Buenos Aires (Argentina)

2014-12-15

We present a full two-fluid magnetohydrodynamic (MHD) description for a completely ionized hydrogen plasma, retaining the effects of the Hall current, electron pressure, and electron inertia. According to this description, each plasma species introduces a new spatial scale: the ion inertial length λ{sub i} and the electron inertial length λ{sub e}, which are not present in the traditional MHD description. In the present paper, we seek for possible changes in the energy power spectrum in fully developed turbulent regimes, using numerical simulations of the two-fluid equations in two-and-a-half dimensions. We have been able to reproduce different scaling laws in different spectral ranges, as it has been observed in the solar wind for the magnetic energy spectrum. At the smallest wavenumbers where plain MHD is valid, we obtain an inertial range following a Kolmogorov k{sup −5∕3} law. For intermediate wavenumbers such that λ{sub i}{sup −1}≪k≪λ{sub e}{sup −1}, the spectrum is modified to a k{sup −7∕3} power-law, as has also been obtained for Hall-MHD neglecting electron inertia terms. When electron inertia is retained, a new spectral region given by k>λ{sub e}{sup −1} arises. The power spectrum for magnetic energy in this region is given by a k{sup −11∕3} power law. Finally, when the terms of electron inertia are retained, we study the self-consistent electric field. Our results are discussed and compared with those obtained in the solar wind observations and previous simulations.

Probing Xe electronic structure by two-color HHG

International Nuclear Information System (INIS)

Faccialà, D; Ciriolo, A G; De Silvestri, S; Devetta, M; Negro, M; Stagira, S; Vozzi, C; Pabst, S; Bruner, B D; Dudovich, N; Soifer, H

2015-01-01

The aim of this study is probing the multi-electron behavior in xenon by two-color driven high harmonic generation. By changing the relative polarization of the two colors we were able to study different aspects of the multi-electron response. (paper)

Genomic and environmental selection patterns in two distinct lettuce crop-wild hybrid crosses

OpenAIRE

Hartman, Y.; Uwimana, B.; Hooftman, D.A.P.; Schranz, M.E.; Wiel, van de, C.C.M.; Smulders, M.J.M.; Visser, R.G.F.; Tienderen, van, P.H.

2013-01-01

Genomic selection patterns and hybrid performance influence the chance that crop (trans)genes can spread to wild relatives. We measured fitness(-related) traits in two different field environments employing two different crop?wild crosses of lettuce. We performed quantitative trait loci (QTL) analyses and estimated the fitness distribution of early- and late-generation hybrids. We detected consistent results across field sites and crosses for a fitness QTL at linkage group 7, where a selectiv...

Timing analysis of two-electron photoemission

International Nuclear Information System (INIS)

Kheifets, A S; Ivanov, I A; Bray, Igor

2011-01-01

We predict a significant delay of two-electron photoemission from the helium atom after absorption of an attosecond XUV pulse. We establish this delay by solving the time-dependent Schroedinger equation and by subsequently tracing the field-free evolution of the two-electron wave packet. This delay can also be related to the energy derivative of the phase of the complex double-photoionization (DPI) amplitude which we evaluate by using the convergent close-coupling method. Our observations indicate that future attosecond time delay measurements on DPI of He can provide information on the absolute quantum phase and elucidate various mechanisms of this strongly correlated ionization process. (fast track communication)

Noninteracting beams of ballistic two-dimensional electrons

International Nuclear Information System (INIS)

Spector, J.; Stormer, H.L.; Baldwin, K.W.; Pfeiffer, L.N.; West, K.W.

1991-01-01

We demonstrate that two beams of two-dimensional ballistic electrons in a GaAs-AlGaAs heterostructure can penetrate each other with negligible mutual interaction analogous to the penetration of two optical beams. This allows electrical signal channels to intersect in the same plane with negligible crosstalk between the channels

Liquid structure and freezing of the two-dimensional classical electron fluid

International Nuclear Information System (INIS)

Ballone, P.; Pastore, G.; Rovere, M.; Tosi, M.P.

1984-11-01

Accurate theoretical results are reported for the pair correlation function of the classical two-dimensional electron liquid with r -1 interactions at strong coupling. The approach involves an evaluation of the bridge diagram corrections to the hypernetted-chain approximation, the role of low dimensionality being evident, relative to the case of the three-dimensional classical plasma, in an enhanced sensitivity to long range correlations. The liquid structure results are utilized in a density-wave theory of first-order freezing into the triangular lattice, the calculated coupling strength at freezing being in reasonable agreement with computer simulation results and with data on electron films on a liquid-He surface. The stability of the triangular electron lattice against deformation into a body-centered rectangular lattice is also discussed. (author)

Two-process approach to electron beam welding control

International Nuclear Information System (INIS)

Lastovirya, V.N.

1987-01-01

The analysis and synthesis of multi-dimensional welding control systems, which require the usage of computers, should be conducted within the temporal range. From the general control theory point two approaches - one-process and two-process - are possible to electron beam welding. In case of two-process approach, subprocesses of heat source formation and direct metal melting are separated. Two-process approach leads to two-profile control system and provides the complete controlability of electron beam welding within the frameworks of systems with concentrated, as well as, with distributed parameters. Approach choice for the given problem solution is determined, first of all, by stability degree of heat source during welding

Genetic origin and composition of a natural hybrid poplar Populus???jrtyschensis from two distantly related species

OpenAIRE

Jiang, Dechun; Feng, Jianju; Dong, Miao; Wu, Guili; Mao, Kangshan; Liu, Jianquan

2016-01-01

Background The factors that contribute to and maintain hybrid zones between distinct species are highly variable, depending on hybrid origins, frequencies and fitness. In this study, we aimed to examine genetic origins, compositions and possible maintenance of Populus???jrtyschensis, an assumed natural hybrid between two distantly related species. This hybrid poplar occurs mainly on the floodplains along the river valleys between the overlapping distributions of the two putative parents. Resu...

Electroluminescence of colloidal quasi-two-dimensional semiconducting CdSe nanostructures in a hybrid light-emitting diode

Energy Technology Data Exchange (ETDEWEB)

Selyukov, A. S., E-mail: vslebedev.mobile@gmail.com; Vitukhnovskii, A. G.; Lebedev, V. S.; Vashchenko, A. A. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Vasiliev, R. B.; Sokolikova, M. S. [Moscow State University (Russian Federation)

2015-04-15

We report on the results of studying quasi-two-dimensional nanostructures synthesized here in the form of semiconducting CdSe nanoplatelets with a characteristic longitudinal size of 20–70 nm and a thick-ness of a few atomic layers. Their morphology is studied using TEM and AFM and X-ray diffraction analysis; the crystal structure and sizes are determined. At room and cryogenic temperatures, the spectra and kinetics of the photoluminescence of such structures (quantum wells) are investigated. A hybrid light-emitting diode operating on the basis of CdSe nanoplatelets as a plane active element (emitter) is developed using the organic materials TAZ and TPD to form electron and hole transport layers, respectively. The spectral and current-voltage characteristics of the constructed device with a radiation wavelength λ = 515 nm are obtained. The device triggering voltage is 5.5 V (visible glow). The use of quasi-two-dimensional structures of this type is promising for hybrid light-emitting diodes with pure color and low operating voltages.

Electroluminescence of colloidal quasi-two-dimensional semiconducting CdSe nanostructures in a hybrid light-emitting diode

International Nuclear Information System (INIS)

Selyukov, A. S.; Vitukhnovskii, A. G.; Lebedev, V. S.; Vashchenko, A. A.; Vasiliev, R. B.; Sokolikova, M. S.

2015-01-01

We report on the results of studying quasi-two-dimensional nanostructures synthesized here in the form of semiconducting CdSe nanoplatelets with a characteristic longitudinal size of 20–70 nm and a thick-ness of a few atomic layers. Their morphology is studied using TEM and AFM and X-ray diffraction analysis; the crystal structure and sizes are determined. At room and cryogenic temperatures, the spectra and kinetics of the photoluminescence of such structures (quantum wells) are investigated. A hybrid light-emitting diode operating on the basis of CdSe nanoplatelets as a plane active element (emitter) is developed using the organic materials TAZ and TPD to form electron and hole transport layers, respectively. The spectral and current-voltage characteristics of the constructed device with a radiation wavelength λ = 515 nm are obtained. The device triggering voltage is 5.5 V (visible glow). The use of quasi-two-dimensional structures of this type is promising for hybrid light-emitting diodes with pure color and low operating voltages

Comparative genetics of hybrid incompatibility: sterility in two Solanum species crosses.

Science.gov (United States)

Moyle, Leonie C; Nakazato, Takuya

2008-07-01

The genetic basis of hybrid sterility can provide insight into the genetic and evolutionary origins of species barriers. We examine the genetics of hybrid incompatibility between two diploid plant species in the plant clade Solanum sect. Lycopersicon. Using a set of near-isogenic lines (NILs) representing the wild species Solanum pennellii (formerly Lycopersicon pennellii) in the genetic background of the cultivated tomato S. lycopersicum (formerly L. esculentum), we found that hybrid pollen and seed infertility are each based on a modest number of loci, male (pollen) and other (seed) incompatibility factors are roughly comparable in number, and seed-infertility QTL act additively or recessively. These findings are remarkably consistent with our previous analysis in a different species pair, S. lycopersicum x S. habrochaites. Data from both studies contrast strongly with data from Drosophila. Finally, QTL for pollen and seed sterility from the two Solanum studies were chromosomally colocalized, indicating a shared evolutionary history for these QTL, a nonrandom genomic distribution of loci causing sterility, and/or a proclivity of certain genes to be involved in hybrid sterility. We show that comparative mapping data can delimit the probable timing of evolution of detected QTL and discern which sterility loci likely evolved earliest among species.

Efficient coherent driving of NV centers in a YIG-nanodiamond hybrid platform

Science.gov (United States)

Andrich, Paolo; de Las Casas, Charles F.; Liu, Xiaoying; Bretscher, Hope L.; Nealey, Paul F.; Awschalom, David D.; Heremans, F. Joseph

The nitrogen-vacancy (NV) center in diamond is an ideal candidate for room temperature quantum computing and sensing applications. These schemes rely on magnetic dipolar interactions between the NV centers and other paramagnetic centers, imposing a stringent limit on the spin-to-spin separation. For instance, creating multi-qubit entanglement requires two NV centers to be within a few nanometers of each other, limiting the possibility for individual optical and microwave (MW) control. Moreover, to sense spins external to the diamond lattice the NV centers need to be within few nanometers from the surface, where their coherence properties are strongly reduced. In this work, we address these limitations using a hybrid YIG-nanodiamond platform where propagating spin-waves (SWs) are used to mediate the interaction between a MW source and a NV center ensemble, thereby relaxing the requirements imposed by dipolar interactions. In particular, we show that SWs can be used to amplify a MW signal detected by the NV centers by more than two orders of magnitude, allowing us to obtain ultra-low energy SW-driven coherent control of the NV centers. These results demonstrate the potentials of YIG-ND hybrid systems for the realization of enhanced quantum sensing and scalable computing devices. This work is supported by the ARO MURI program and the AFOSR.

Mitochondria-targeted cationic porphyrin-triphenylamine hybrids for enhanced two-photon photodynamic therapy.

Science.gov (United States)

Hammerer, Fabien; Poyer, Florent; Fourmois, Laura; Chen, Su; Garcia, Guillaume; Teulade-Fichou, Marie-Paule; Maillard, Philippe; Mahuteau-Betzer, Florence

2018-01-01

The proof of concept for two-photon activated photodynamic therapy has already been achieved for cancer treatment but the efficiency of this approach still heavily relies on the availability of photosensitizers combining high two-photon absorption and biocompatibility. In this line we recently reported on a series of porphyrin-triphenylamine hybrids which exhibit high singlet oxygen production quantum yield as well as high two-photon absorption cross-sections but with a very poor cellular internalization. We present herein new photosensitizers of the same porphyrin-triphenylamine hybrid series but bearing cationic charges which led to strongly enhanced water solubility and thus cellular penetration. In addition the new compounds have been found localized in mitochondria that are preferential target organelles for photodynamic therapy. Altogether the strongly improved properties of the new series combined with their specific mitochondrial localization lead to a significantly enhanced two-photon activated photodynamic therapy efficiency. Copyright © 2017 Elsevier Ltd. All rights reserved.

Electronic band structure of Two-Dimensional WS2/Graphene van der Waals Heterostructures

Science.gov (United States)

Henck, Hugo; Ben Aziza, Zeineb; Pierucci, Debora; Laourine, Feriel; Reale, Francesco; Palczynski, Pawel; Chaste, Julien; Silly, Mathieu G.; Bertran, François; Le Fèvre, Patrick; Lhuillier, Emmanuel; Wakamura, Taro; Mattevi, Cecilia; Rault, Julien E.; Calandra, Matteo; Ouerghi, Abdelkarim

2018-04-01

Combining single-layer two-dimensional semiconducting transition-metal dichalcogenides (TMDs) with a graphene layer in van der Waals heterostructures offers an intriguing means of controlling the electronic properties through these heterostructures. Here, we report the electronic and structural properties of transferred single-layer W S2 on epitaxial graphene using micro-Raman spectroscopy, angle-resolved photoemission spectroscopy measurements, and density functional theory (DFT) calculations. The results show good electronic properties as well as a well-defined band arising from the strong splitting of the single-layer W S2 valence band at the K points, with a maximum splitting of 0.44 eV. By comparing our DFT results with local and hybrid functionals, we find the top valence band of the experimental heterostructure is close to the calculations for suspended single-layer W S2 . Our results provide an important reference for future studies of electronic properties of W S2 and its applications in valleytronic devices.

The Two-Beam Free Electron Laser Oscillator

CERN Document Server

Thompson, Neil R

2004-01-01

A one-dimensional model of a free-electron laser operating simultaneously with two electron beams of different energies [1] is extended to an oscillator configuration. The electron beam energies are chosen so that an harmonic of the lower energy beam is at the fundamental radiation wavelength of the higher energy beam. Potential benefits over a single-beam free-electron laser oscillator are discussed.

some generalized two-step block hybrid numerov method for solving ...

African Journals Online (AJOL)

Nwokem et al.

ABSTRACT. This paper proposes a class of generalized two-step Numerov methods, a block hybrid type for the direct solution of general second order ordinary differential equations. Both the main method and additional methods were derived via interpolation and collocation procedures. The basic properties of zero ...

Electron Bifurcation: Thermodynamics and Kinetics of Two-Electron Brokering in Biological Redox Chemistry

Energy Technology Data Exchange (ETDEWEB)

Zhang, Peng; Yuly, Jonathon L.; Lubner, Carolyn E. [National Renewable Energy Laboratory, Golden, Colorado 80401, United States; Mulder, David W. [National Renewable Energy Laboratory, Golden, Colorado 80401, United States; King, Paul W. [National Renewable Energy Laboratory, Golden, Colorado 80401, United States; Peters, John W. [Institute; Beratan, David N. [Department

2017-08-23

How can proteins drive two electrons from a redox active donor onto two acceptors at very different potentials and distances? And how can this transaction be conducted without dissipating very much energy or violating the laws of thermodynamics? Nature appears to have addressed these challenges by coupling thermodynamically uphill and downhill electron transfer reactions, using two-electron donor cofactors that have very different potentials for the removal of the first and second electron. Although electron bifurcation is carried out with near perfection from the standpoint of energy conservation and electron delivery yields, it is a biological energy transduction paradigm that has only come into focus recently. This Account provides an exegesis of the biophysical principles that underpin electron bifurcation.

Experimental Comparison of Two Configurations of Hybrid Photovoltaic Thermal Collectors

International Nuclear Information System (INIS)

Khaled Toufeka; Mourad Haddadib; Ali Mkc

2011-01-01

The combination of a thermal collector and a photovoltaic module in a single system allows for increased efficiency of the total conversion of solar energy. A synergistic effect can be obtained in a structure combining these two devices in a judicious manner to those of thermal and photovoltaic system installed separately. Production of total energy from hybrid collector depends on the input (that is to say, the. energy of solar radiation, air temperature and wind speed) and output which is the electric production and the temperature of the system. Thin production also depends on the mode of heal extraction. In this paper, an experimental Study of two configurations of hybrid collectors is described. The configuration that the absorber is made by galvanized steel and in the second, the absorber is a copper serpentine. The advantages of the first configuration are mainly due to low cost and simplicity but the second configuration has the advantage of promoting the heat transfer between cells and fluid. (authors)

On Symmetries of Extremal Black Holes with One and Two Centers

CERN Document Server

Ferrara, Sergio

2013-01-01

After a brief introduction to the Attractor Mechanism, we review the appearance of groups of type E7 as generalized electric-magnetic duality symmetries in locally supersymmetric theories of gravity, with particular emphasis on the symplectic structure of fluxes in the background of extremal black hole solutions, with one or two centers. In the latter case, the role of an "horizontal" symmetry SL(2,R) is elucidated by presenting a set of two-centered relations governing the structure of two-centered invariant polynomials.

Electronic and magnetic properties of modified silicene/graphene hybrid: Ab initio study

Energy Technology Data Exchange (ETDEWEB)

Chowdhury, Suman; Jana, Debnarayan, E-mail: cujanad@yahoo.com

2016-11-01

Among other two-dimensional (2D) novel materials, graphene and silicene both have drawn intense research interest among the researchers because they possess some unique intriguing properties which can change the scenario of the current electronic industry. In this work we have studied the electronic and the magnetic properties of a new kind of materials which is the hybrid of these two materials. Density functional theory (DFT) has been employed to calculate the relevant electronic and magnetic properties of this hybrid material. The pristine structure is modified by substitutional doping or by creating vacancy (Y-X, where one Y atom (Si or C) has been replaced by one X atom (B, N, Al, P or void)). The calculations have revealed that void systems are unstable while Si-B and Si-N are most stable ones. It has been noticed that some of these doped structures are magnetic in nature having induced mid-gap states in the system. In particular, Si-void structure is unstable yet it possess the highest magnetic moment of the order of 4 μ{sub B} (μ{sub B} being the Bohr magneton). The estimated band gaps of modified silicene/graphene hybrid from spin polarized partial density of states (PDOS) vary between 1.43–2.38 eV and 1.58–2.50 eV for spin-up and spin-down channel respectively. The implication of midgap states has been critically analysed in the light of magnetic nature. This study may be useful to build hybrid spintronic devices with controllable gap for spin up and spin down states. - Graphical abstract: We have studied the electronic and magnetic properties of silicene/graphene hybrid by employing density functional theory (DFT). - Highlights: • Electronic and magnetic properties of two dimensional graphene/silicene hybrid have been explored. • There is no magnetism in the system for a single carbon atom vacancy. • A net magnetic moment of 4.0 Bohr magneton is observed for a single silicon atom vacancy. • Unpaired electrons introduce mid-gap states which

Upper-hybrid solitons and oscillating-two-stream instabilities

International Nuclear Information System (INIS)

Porkolab, M.; Goldman, M.V.

1976-01-01

A warm two-fluid theory of soliton formation near the upper-hybrid frequency is developed. Several forms of the nonlinear Schrodinger equation are obtained, depending on whether the electric field is completely perpendicular to the dc magnetic field or whether it has an additional small component parallel to the magnetic field. For the perpendicular case, the character of the soliton depends on its scale length, L, and on β. For low β, when L c/ω/subp//subi/ the super-Alvenic solitons described magnetohydromagnetically by Kaufman and Stenflo are obtained. However, the case E/sub parallel/not-equal0 may be of more interest, since it couples the pump to the excited waves more efficiently. In the limit of linearization about an infinite wavelength pump, the nonlinear Schrodinger equations yield purely growing (oscillating-two-stream) instabilities in both cases

A compact CMA spectrometer with axially integrated hybrid electron-ion gun for ISS, AES and sputter depth profile analysis

International Nuclear Information System (INIS)

Gisler, E.; Bas, E.B.

1986-01-01

Until now, the combined application of electrons and ions in surface analysis required two separate sources for electrons and ions with different incidence angles. The newly developed hybrid electron-ion gun, however, allows bombardment of the same sample area both with noble gas ions and with electrons coming from the same direction. By integrating such a hybrid gun axially in a cylindrical mirror energy analyser (CMA) a sensitive compact single flange spectrometer obtains for ion scattering spectroscopy (ISS), Auger electron spectroscopy (AES), and sputtering all within normal beam incidence. This concept makes accurate beam centering very easy. Additionally, the bombardment from the same direction both for sputtering and for surface analysis brings advantages in depth profiling. The scattering angle for ISS has a constant value of about 138 0 . The hybrid gun delivers typically an electron beam current of -20μA at 3keV for AES, and an ion beam current of +40 nA and +1.2μA at 2 keV for ISS and sputtering respectively. The switching time between ISS, AES, and sputtering mode is about 0.1 s. So this system is best suited for automatically controlled depth profile analysis. The design and operation of this new system will be described and some applications will be discussed. (author)

Whole-cell hybridization of Methanosarcina cells with two new oligonucleotide probes

DEFF Research Database (Denmark)

Sørensen, A.H.; Torsvik, V.L.; Torsvik, T.

1997-01-01

Two new oligonucleotide probes targeting the 16S rRNA of the methanogenic genus Methanosarcina were developed. The probes have the following sequences (Escherichia coli numbering): probe SARCI551, 5'-GAC CCAATAATCACGATCAC-3', and probe SARCI645, 5'-TCCCGGTTCCAAGTCTGGC-3'. In situ hybridization...... with the fluorescently labelled probes required several modifications of standard procedures. Cells of Methanosarcina mazeii S-6 were found to lyse during the hybridization step if fixed in 3% formaldehyde and stored in 50% ethanol. Lysis was, however, not observed with cells fixed and stored in 1.6% formaldehyde-0.......85% NaCl. Extensive autofluorescence of the cells was found upon hybridization in the presence of 5 mM EDTA, but successful hybridization could be obtained without addition of this compound. The mounting agent Citifluor AF1, often used in conjugation with the fluorochrome fluorescein, was found to wash...

Enabling fast electron transfer through both bacterial outer-membrane redox centers and endogenous electron mediators by polyaniline hybridized large-mesoporous carbon anode for high-performance microbial fuel cells

International Nuclear Information System (INIS)

Zou, Long; Qiao, Yan; Zhong, Canyu; Li, Chang Ming

2017-01-01

Both physical structure and chemical property of an electrode play critical roles in extracellular electron transfer from microbes to electrodes in microbial fuel cells (MFCs). Herein a novel polyaniline hybridized large mesoporous carbon (PANI-LMC) anode is fabricated from natural biomass by nanostructured CaCO 3 template-assisted carbonization followed by in situ chemical polymerizing PANI to enable fast extracellular electron transfer, in which the LMC with rich disorder-interconnected large mesopores (∼20−50 nm) and large surface area facilitates a fast mediated electron transfer through electron mediators, while the decorated PANI on LMC surface enables the direct electron transfer via bacterial outer-membrane redox centers. Owing to the unique synergistic effect from both excellent electron transfer paths, the PANI-LMC hybrid anode harvests high power electricity with a maximum output power density of 1280 mW m −2 in Shewanella putrefaciens CN32 MFCs, 10-fold higher than that of conventional carbon cloth. The findings from this work suggest a new insight on design of high-efficient anode according to the multiple and flexible electrochemical process for practical MFC applications.

Genetic origin and composition of a natural hybrid poplar Populus × jrtyschensis from two distantly related species.

Science.gov (United States)

Jiang, Dechun; Feng, Jianju; Dong, Miao; Wu, Guili; Mao, Kangshan; Liu, Jianquan

2016-04-18

The factors that contribute to and maintain hybrid zones between distinct species are highly variable, depending on hybrid origins, frequencies and fitness. In this study, we aimed to examine genetic origins, compositions and possible maintenance of Populus × jrtyschensis, an assumed natural hybrid between two distantly related species. This hybrid poplar occurs mainly on the floodplains along the river valleys between the overlapping distributions of the two putative parents. We collected 566 individuals from 45 typical populations of P. × jrtyschensis, P. nigra and P. laurifolia. We genotyped them based on the sequence variations of one maternally inherited chloroplast DNA (cpDNA) fragment and genetic polymorphisms at 20 SSR loci. We further sequenced eight nuclear genes for 168 individuals from 31 populations. Two groups of cpDNA haplotypes characteristic of P. nigra and P. laurifolia respectively were both recovered for P. × jrtyschensis. Genetic structures and coalescent tests of two sets of nuclear population genetic data suggested that P. × jrtyschensis originated from hybridizations between the two assumed parental species. All examined populations of P. × jrtyschensis comprise mainly F1 hybrids from interspecific hybridizations between P. nigra and P. laurifolia. In the habitats of P. × jrtyschensis, there are lower concentrations of soil nitrogen than in the habitats occupied by the other two species. Our extensive examination of the genetic composition of P. × jrtyschensis suggested that it is typical of F1-dominated hybrid zones. This finding plus the low concentration of soil nitrogen in the floodplain soils support the F1-dominated bounded hybrid superiority hypothesis of hybrid zone maintenance for this particular hybrid poplar.

Spectroscopy of two-electron atoms

International Nuclear Information System (INIS)

Desesquelles, J.

1988-01-01

Spectroscopy of heliumlike ions is discussed putting emphasis on mid and high Z atoms. Experimental aspects of ion charge, excitation production, clean spectra, and precise wavelength measurement are detailed. Recent results obtained at several laboratories including Lyon, Argonne, Notre-Dame, Oxford, Berkeley, Darmstadt, Paris, are used to test the QED contributions and higher order relativistic corrections to two-electron atom energies. (orig.)

Genomic and environmental selection patterns in two distinct lettuce crop-wild hybrid crosses

NARCIS (Netherlands)

Hartman, Y.; Uwimana, B; Hooftman, D.A.P.; Schranz, M.E.; van de Wiel, C.C.M.; Smulders, M.J.M.; Visser, R.G.F.; van Tienderen, P.H.

2013-01-01

Genomic selection patterns and hybrid performance influence the chance that crop (trans)genes can spread to wild relatives. We measured fitness(-related) traits in two different field environments employing two different crop-wild crosses of lettuce. We performed quantitative trait loci (QTL)

Genomic and environmental selection patterns in two distinct lettuce crop-wild hybrid crosses

NARCIS (Netherlands)

Hartman, Y.; Uwimana, B.; Hooftman, D.A.P.; Schranz, M.E.; Wiel, van de C.C.M.; Smulders, M.J.M.; Visser, R.G.F.; Tienderen, van P.H.

2013-01-01

Genomic selection patterns and hybrid performance influence the chance that crop (trans)genes can spread to wild relatives. We measured fitness(-related) traits in two different field environments employing two different crop–wild crosses of lettuce. We performed quantitative trait loci (QTL)

Electron Bifurcation: Thermodynamics and Kinetics of Two-Electron Brokering in Biological Redox Chemistry.

Science.gov (United States)

Zhang, Peng; Yuly, Jonathon L; Lubner, Carolyn E; Mulder, David W; King, Paul W; Peters, John W; Beratan, David N

2017-09-19

How can proteins drive two electrons from a redox active donor onto two acceptors at very different potentials and distances? And how can this transaction be conducted without dissipating very much energy or violating the laws of thermodynamics? Nature appears to have addressed these challenges by coupling thermodynamically uphill and downhill electron transfer reactions, using two-electron donor cofactors that have very different potentials for the removal of the first and second electron. Although electron bifurcation is carried out with near perfection from the standpoint of energy conservation and electron delivery yields, it is a biological energy transduction paradigm that has only come into focus recently. This Account provides an exegesis of the biophysical principles that underpin electron bifurcation. Remarkably, bifurcating electron transfer (ET) proteins typically send one electron uphill and one electron downhill by similar energies, such that the overall reaction is spontaneous, but not profligate. Electron bifurcation in the NADH-dependent reduced ferredoxin: NADP + oxidoreductase I (Nfn) is explored in detail here. Recent experimental progress in understanding the structure and function of Nfn allows us to dissect its workings in the framework of modern ET theory. The first electron that leaves the two-electron donor flavin (L-FAD) executes a positive free energy "uphill" reaction, and the departure of this electron switches on a second thermodynamically spontaneous ET reaction from the flavin along a second pathway that moves electrons in the opposite direction and at a very different potential. The singly reduced ET products formed from the bifurcating flavin are more than two nanometers distant from each other. In Nfn, the second electron to leave the flavin is much more reducing than the first: the potentials are said to be "crossed." The eventually reduced cofactors, NADH and ferredoxin in the case of Nfn, perform crucial downstream redox

Multiple Origins of the Pathogenic Yeast Candida orthopsilosis by Separate Hybridizations between Two Parental Species.

Science.gov (United States)

Schröder, Markus S; Martinez de San Vicente, Kontxi; Prandini, Tâmara H R; Hammel, Stephen; Higgins, Desmond G; Bagagli, Eduardo; Wolfe, Kenneth H; Butler, Geraldine

2016-11-01

Mating between different species produces hybrids that are usually asexual and stuck as diploids, but can also lead to the formation of new species. Here, we report the genome sequences of 27 isolates of the pathogenic yeast Candida orthopsilosis. We find that most isolates are diploid hybrids, products of mating between two unknown parental species (A and B) that are 5% divergent in sequence. Isolates vary greatly in the extent of homogenization between A and B, making their genomes a mosaic of highly heterozygous regions interspersed with homozygous regions. Separate phylogenetic analyses of SNPs in the A- and B-derived portions of the genome produces almost identical trees of the isolates with four major clades. However, the presence of two mutually exclusive genotype combinations at the mating type locus, and recombinant mitochondrial genomes diagnostic of inter-clade mating, shows that the species C. orthopsilosis does not have a single evolutionary origin but was created at least four times by separate interspecies hybridizations between parents A and B. Older hybrids have lost more heterozygosity. We also identify two isolates with homozygous genomes derived exclusively from parent A, which are pure non-hybrid strains. The parallel emergence of the same hybrid species from multiple independent hybridization events is common in plant evolution, but is much less documented in pathogenic fungi.

Multiple Origins of the Pathogenic Yeast Candida orthopsilosis by Separate Hybridizations between Two Parental Species.

Directory of Open Access Journals (Sweden)

Markus S Schröder

2016-11-01

Full Text Available Mating between different species produces hybrids that are usually asexual and stuck as diploids, but can also lead to the formation of new species. Here, we report the genome sequences of 27 isolates of the pathogenic yeast Candida orthopsilosis. We find that most isolates are diploid hybrids, products of mating between two unknown parental species (A and B that are 5% divergent in sequence. Isolates vary greatly in the extent of homogenization between A and B, making their genomes a mosaic of highly heterozygous regions interspersed with homozygous regions. Separate phylogenetic analyses of SNPs in the A- and B-derived portions of the genome produces almost identical trees of the isolates with four major clades. However, the presence of two mutually exclusive genotype combinations at the mating type locus, and recombinant mitochondrial genomes diagnostic of inter-clade mating, shows that the species C. orthopsilosis does not have a single evolutionary origin but was created at least four times by separate interspecies hybridizations between parents A and B. Older hybrids have lost more heterozygosity. We also identify two isolates with homozygous genomes derived exclusively from parent A, which are pure non-hybrid strains. The parallel emergence of the same hybrid species from multiple independent hybridization events is common in plant evolution, but is much less documented in pathogenic fungi.

Observation of Internal Photoinduced Electron and Hole Separation in Hybrid Two-Dimentional Perovskite Films.

Science.gov (United States)

Liu, Junxue; Leng, Jing; Wu, Kaifeng; Zhang, Jun; Jin, Shengye

2017-02-01

Two-dimensional (2D) organolead halide perovskites are promising for various optoelectronic applications. Here we report a unique spontaneous charge (electron/hole) separation property in multilayered (BA) 2 (MA) n-1 Pb n I 3n+1 (BA = CH 3 (CH 2 ) 3 NH 3 + , MA = CH 3 NH 3 + ) 2D perovskite films by studying the charge carrier dynamics using ultrafast transient absorption and photoluminescence spectroscopy. Surprisingly, the 2D perovskite films, although nominally prepared as "n = 4", are found to be mixture of multiple perovskite phases, with n = 2, 3, 4 and ≈ ∞, that naturally align in the order of n along the direction perpendicular to the substrate. Driven by the band alignment between 2D perovskites phases, we observe consecutive photoinduced electron transfer from small-n to large-n phases and hole transfer in the opposite direction on hundreds of picoseconds inside the 2D film of ∼358 nm thickness. This internal charge transfer efficiently separates electrons and holes to the upper and bottom surfaces of the films, which is a unique property beneficial for applications in photovoltaics and other optoelectronics devices.

A Gateway((R)) -compatible bacterial adenylate cyclase-based two-hybrid system

Czech Academy of Sciences Publication Activity Database

Ouellette, S. P.; Gauliard, E.; Antošová, Zuzana; Ladant, D.

2014-01-01

Roč. 6, č. 3 (2014), s. 259-267 ISSN 1758-2229 Institutional support: RVO:67985823 Keywords : bacterial two-hybrid system * protein–protein interactions * cell division * Gateway((R))(GW) cloning system Subject RIV: EE - Microbiology, Virology Impact factor: 3.293, year: 2014

Improvement of two-stage GM refrigerator performance using a hybrid regenerator

International Nuclear Information System (INIS)

Ke, G.; Makuuchi, H.; Hashimoto, T.; Onishi, A.; Li, R.; Satoh, T.; Kanazawa, Y.

1994-01-01

To improve the performance of two-stage GM refrigerators, a hybrid regenerator with magnetic materials of Er 3 Ni and ErNi 0.9 Co 0.1 was used in the 2nd stage regenerator because of its large heat exchange capacity. The largest refrigeration capacity achieved with the hybrid regenerator was 0.95W at helium liquefied temperature of 4.2K. This capacity is 15.9% greater than the 0.82W refrigerator with only Er 3 Ni as the 2nd regenerator material. Use of the hybrid regenerator not only increases the refrigeration capacity at 4.2K, but also allows the 4K GM refrigerator to be used with large 1st stage refrigeration capacity, thus making it more practical

Two-center Coulomb problem with Calogero interaction

Energy Technology Data Exchange (ETDEWEB)

Hakobyan, T., E-mail: tigran.hakobyan@ysu.am; Nersessian, A., E-mail: arnerses@ysu.am [Armenia Tomsk Polytechnic University, Yerevan State University (Russian Federation)

2017-03-15

We show that the Calogero-type perturbation preserves the integrability and partial separation of variables for the Stark–Coulomb and two-center Coulomb problems, and present the explicit expressions of their constants of motion. We reveal that this perturbation preserves the spectra of initial systems, but leads to the change of degree of degeneracy.

Mechanisms Underlying Mammalian Hybrid Sterility in Two Feline Interspecies Models.

Science.gov (United States)

Davis, Brian W; Seabury, Christopher M; Brashear, Wesley A; Li, Gang; Roelke-Parker, Melody; Murphy, William J

2015-10-01

The phenomenon of male sterility in interspecies hybrids has been observed for over a century, however, few genes influencing this recurrent phenotype have been identified. Genetic investigations have been primarily limited to a small number of model organisms, thus limiting our understanding of the underlying molecular basis of this well-documented "rule of speciation." We utilized two interspecies hybrid cat breeds in a genome-wide association study employing the Illumina 63 K single-nucleotide polymorphism array. Collectively, we identified eight autosomal genes/gene regions underlying associations with hybrid male sterility (HMS) involved in the function of the blood-testis barrier, gamete structural development, and transcriptional regulation. We also identified several candidate hybrid sterility regions on the X chromosome, with most residing in close proximity to complex duplicated regions. Differential gene expression analyses revealed significant chromosome-wide upregulation of X chromosome transcripts in testes of sterile hybrids, which were enriched for genes involved in chromatin regulation of gene expression. Our expression results parallel those reported in Mus hybrids, supporting the "Large X-Effect" in mammalian HMS and the potential epigenetic basis for this phenomenon. These results support the value of the interspecies feline model as a powerful tool for comparison to rodent models of HMS, demonstrating unique aspects and potential commonalities that underpin mammalian reproductive isolation. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Travelling in time with networks: Revealing present day hybridization versus ancestral polymorphism between two species of brown algae, Fucus vesiculosus and F. spiralis

Directory of Open Access Journals (Sweden)

Pearson Gareth A

2011-01-01

Full Text Available Abstract Background Hybridization or divergence between sympatric sister species provides a natural laboratory to study speciation processes. The shared polymorphism in sister species may either be ancestral or derive from hybridization, and the accuracy of analytic methods used thus far to derive convincing evidence for the occurrence of present day hybridization is largely debated. Results Here we propose the application of network analysis to test for the occurrence of present day hybridization between the two species of brown algae Fucus spiralis and F. vesiculosus. Individual-centered networks were analyzed on the basis of microsatellite genotypes from North Africa to the Pacific American coast, through the North Atlantic. Two genetic distances integrating different time steps were used, the Rozenfeld (RD; based on alleles divergence and the Shared Allele (SAD; based on alleles identity distances. A diagnostic level of genotype divergence and clustering of individuals from each species was obtained through RD while screening for exchanges through putative hybridization was facilitated using SAD. Intermediate individuals linking both clusters on the RD network were those sampled at the limits of the sympatric zone in Northwest Iberia. Conclusion These results suggesting rare hybridization were confirmed by simulation of hybrids and F2 with directed backcrosses. Comparison with the Bayesian method STRUCTURE confirmed the usefulness of both approaches and emphasized the reliability of network analysis to unravel and study hybridization

Exact wave functions of two-electron quantum rings.

Science.gov (United States)

Loos, Pierre-François; Gill, Peter M W

2012-02-24

We demonstrate that the Schrödinger equation for two electrons on a ring, which is the usual paradigm to model quantum rings, is solvable in closed form for particular values of the radius. We show that both polynomial and irrational solutions can be found for any value of the angular momentum and that the singlet and triplet manifolds, which are degenerate, have distinct geometric phases. We also study the nodal structure associated with these two-electron states.

Study on Two-segment Electric-mechanical Composite Braking Strategy of Tracked Vehicle Hybrid Transmission System

OpenAIRE

Ma, Tian; Gai, Jiangtao; Ma, Xiaofeng

2010-01-01

In order to lighten abrasion of braking system of hybrid electric tracked vehicle, according to characteristic of hybrid electric transmission, electric-mechanical composite braking method was proposed. By means of analyzing performance of electric braking and mechanical braking and three-segment composite braking strategy, two-segment electric-mechanical composite braking strategy was put forward in this paper. Simulation results of Matlab/Simulink indicated that the two-segment electric-mec...

Nutritional characteristics of two pigeon pea hybrids – Liming and phosphated fertilization

Directory of Open Access Journals (Sweden)

Marcia Atauri Cardelli de Lucena

2012-12-01

Full Text Available The use of legumes in animal production systems can be a sustainable alternative as a protein source in rotational grazing system and/or as a protein bank. Pigeon pea (Cajanus cajan (L. Millsp. figure as an example of success of this use on animal nutrition. The development of this species can be limited by the high acidity and low soil phosphorus content. There is a lack of scientific information on the effects of liming and phosphorus fertilization on some nutritional variables of two pigeon pea new hybrids. This study was conducted in pots containing 5 kg of soil in a greenhouse at the Instituto de Zootecnia, Nova Odessa, São Paulo State. There were studied two pigeon pea hybrids, H1 and H2, and the treatments involved agronomic practices: 1 No liming and without phosphorus (control, 2 Liming (L, 3 Phosphorus fertilization (P and 4 Liming plus phosphorus. Liming was proposed to increase soil base saturation to 50%, it was used dolomite lime PRNT = 90%, in an amount corresponding to 4.5 t/ha. Phosphorus fertilization (as superphosphate rate was 60 kg/ha of PO25. The experimental units were allocated according to a complete randomised block design, with five replications. We analyzed the levels of crude protein (CP, neutral detergent fiber (NDF, acid detergent fiber (ADF, in pigeon pea shoot at 45 days of age. Statistical analyzes were performed using the software SISVAR, averages were compared using test for multiple comparisons Student Newman-Keuls - SNK test (P < 0.05. The H1 hybrid had the highest content of CP, by applying P, lime plus P and the control treatment compared to H2 hybrid. The association lime plus P resulted in higher content of CP mainly due to the increased availability of P for plants. Smaller values were observed for NDF in H2 with P application. Lower values of ADF were observed in H1 in both control treatment and P application. The ADF values were lower for the hybrid H2 only for the treatment lime plus P. The two

Valence electronic structure of cobalt phthalocyanine from an optimally tuned range-separated hybrid functional.

Science.gov (United States)

Brumboiu, Iulia Emilia; Prokopiou, Georgia; Kronik, Leeor; Brena, Barbara

2017-07-28

We analyse the valence electronic structure of cobalt phthalocyanine (CoPc) by means of optimally tuning a range-separated hybrid functional. The tuning is performed by modifying both the amount of short-range exact exchange (α) included in the hybrid functional and the range-separation parameter (γ), with two strategies employed for finding the optimal γ for each α. The influence of these two parameters on the structural, electronic, and magnetic properties of CoPc is thoroughly investigated. The electronic structure is found to be very sensitive to the amount and range in which the exact exchange is included. The electronic structure obtained using the optimal parameters is compared to gas-phase photo-electron data and GW calculations, with the unoccupied states additionally compared with inverse photo-electron spectroscopy measurements. The calculated spectrum with tuned γ, determined for the optimal value of α = 0.1, yields a very good agreement with both experimental results and with GW calculations that well-reproduce the experimental data.

Quadrupole moments as measures of electron correlation in two-electron atoms

International Nuclear Information System (INIS)

Ceraulo, S.C.; Berry, R.S.

1991-01-01

We have calculated quadrupole moments, Q zz , of helium in several of its doubly excited states and in two of its singly excited Rydberg states, and of the alkaline-earth atoms Be, Mg, Ca, Sr, and Ba in their ground and low-lying excited states. The calculations use well-converged, frozen-core configuration-interaction (CI) wave functions and, for interpretive purposes, Hartree-Fock (HF) atomic wave functions and single-term, optimized, molecular rotor-vibrator (RV) wave functions. The quadrupole moments calculated using RV wave functions serve as a test of the validity of the correlated, moleculelike model, which has been used to describe the effects of electron correlation in these two-electron and pseudo-two-electron atoms. Likewise, the quadrupole moments calculated with HF wave functions test the validity of the independent-particle model. In addition to their predictive use and their application to testing simple models, the quadrupole moments calculated with CI wave functions reveal previously unavailable information about the electronic structure of these atoms. Experimental methods by which these quadrupole moments might be measured are also discussed. The quadrupole moments computed from CI wave functions are presented as predictions; measurements of Q zz have been made for only two singly excited Rydberg states of He, and a value of Q zz has been computed previously for only one of the states reported here. We present these results in the hope of stimulating others to measure some of these quadrupole moments

Absolute Negative Resistance Induced by Directional Electron-Electron Scattering in a Two-Dimensional Electron Gas

Science.gov (United States)

Kaya, Ismet I.; Eberl, Karl

2007-05-01

A three-terminal device formed by two electrostatic barriers crossing an asymmetrically patterned two-dimensional electron gas displays an unusual potential depression at the middle contact, yielding absolute negative resistance. The device displays momentum and current transfer ratios that far exceed unity. The observed reversal of the current or potential in the middle terminal can be interpreted as the analog of Bernoulli’s effect in a Fermi liquid. The results are explained by directional scattering of electrons in two dimensions.

Electronic structure of deep impurity centers in silicon

International Nuclear Information System (INIS)

Oosten, A.B. van.

1989-01-01

This thesis reports an experimental study of deep level impurity centers in silicon, with much attention for theoretical interpretation of the data. A detailed picture of the electronic structure of several centers was obtained by magnetic resonance techniques, such as electron paramagnetic resonance (EPR), electron-nuclear double resonance (ENDOR) and field scanned ENDOR (FSE). The thesis consists of two parts. The first part deals with chalcogen (sulfur, selenium and tellurium) related impurities, which are mostly double donors. The second part is about late transition metal (nickel, palladium and platinum) impurities, which are single (Pd,Pt) or double (Ni) acceptor centers. (author). 155 refs.; 51 figs.; 23 tabs

Hybrid functional calculation of electronic and phonon structure of BaSnO3

International Nuclear Information System (INIS)

Kim, Bog G.; Jo, J.Y.; Cheong, S.W.

2013-01-01

Barium stannate, BaSnO 3 (BSO), with a cubic perovskite structure, has been highlighted as a promising host material for the next generation transparent oxide electrodes. This study examined theoretically the electronic structure and phonon structure of BSO using hybrid density functional theory based on the HSE06 functional. The electronic structure results of BSO were corrected by extending the phonon calculations based on the hybrid density functional. The fundamental thermal properties were also predicted based on a hybrid functional calculation. Overall, a detailed understanding of the electronic structure, phonon modes and phonon dispersion of BSO will provide a theoretical starting-point for engineering applications of this material. - Graphical Abstract: (a) Crystal structure of BaSnO 3 . The center ball is Ba and small (red) ball on edge is oxygen and SnO 6 octahedrons are plotted as polyhedron. (b) Electronic band structure along the high symmetry point in the Brillouin zone using the HSE06 hybrid functional. (c) The phonon dispersion curve calculated using the HSE06 hybrid functional (d) Zone center lowest energy F 1u phonon mode. Highlights: ► We report the full hybrid functional calculation of not only the electronic structure but also the phonon structure for BaSnO 3 . ► The band gap calculation of HSE06 revealed an indirect gap with 2.48 eV. ► The effective mass at the conduction band minimum and valence band maximum was calculated. ► In addition, the phonon structure of BSO was calculated using the HSE06 functional. ► Finally, the heat capacity was calculated and compared with the recent experimental result.

Dynamics of two-electron excitations in helium

Energy Technology Data Exchange (ETDEWEB)

Caldwell, C.D.; Menzel, A.; Frigo, S.P. [Univ. of Central Florida, Orlando, FL (United States)] [and others

1997-04-01

Excitation of both electrons in helium offers a unique window for studying electron correlation at the most basic level in an atom in which these two electrons and the nucleus form a three-body system. The authors utilized the first light available at the U-8 undulator-SGM monochromator beamline to investigate the dynamic parameters, partial cross sections, differential cross sections, and photoelectron angular distribution parameters ({beta}), with a high resolving power for the photon beam and at the highly differential level afforded by the use of their electron spectrometer. In parallel, they carried out detailed calculations of the relevant properties by a theoretical approach that is based on the hyperspherical close-coupling method. Partial photoionization cross sections {sigma}{sub n}, and photoelectron angular distributions {beta}{sub n} were measured for all possible final ionic states He{sup +}(n) in the region of the double excitations N(K,T){sup A} up to the N=5 threshold. At a photon energy bandpass of 12 meV below the thresholds N=3, 4, and 5, this level of differentiation offers the most critical assessment of the dynamics of the two-electron excitations to date. The experimental data were seen to be very well described by the most advanced theoretical calculations.

Coherent electron focusing with quantum point contacts in a two-dimensional electron gas

NARCIS (Netherlands)

Houten, H. van; Beenakker, C.W.J.; Williamson, J.G.; Broekaart, M.E.I.; Loosdrecht, P.H.M. van; Wees, B.J. van; Mooij, J.E.; Foxon, C.T.; Harris, J.J.

1989-01-01

Transverse electron focusing in a two-dimensional electron gas is investigated experimentally and theoretically for the first time. A split Schottky gate on top of a GaAs-AlxGa1–xAs heterostructure defines two point contacts of variable width, which are used as injector and collector of ballistic

Two-electron one-photon decay rates in doubly ionized atoms

International Nuclear Information System (INIS)

Baptista, G.B.

1984-01-01

The transion rate for the two-electron one-photon and one-electron one-photon decaying processes in atoms bearing initially two K-shell vacancies were evaluated for Ne up to Zr. The two-electron one-photon decay process is considered to be the result of the interaction between the jumping electrons and their interaction with the radiation field. The calculation is performed in second order perturbation theory and the many particle states are constructed from single particle solutions. The present approach allows one to discuss several aspects of the decaying process. The results obtained for the branching ratio between the two processes reproduces reasonably well available experimental data and show an almost linear dependence on the second power of the atomic number. A comparison with other theoretical predictions is also presented for the two decaying processes and the strong dependence of the branching ratio on the initial configuration of the decaying atom is pointed out. (Author) [pt

Formation of intermediate shocks in both two-fluid and hybrid models

International Nuclear Information System (INIS)

Wu, C.C.; Hada, T.

1991-01-01

Intermediate shocks are shocks with shock frame fluid velocities greater than the Alfven speed ahead and less than the Alfven speed behind, or equivalently, across intermediate shocks the sign of the transverse component of the magnetic field changes. These shocks had been considered extraneous, or nonevolutionary, or unstable, and they had been thought not to correspond to physical reality [Germain, 1960; Jeffrey and Taniuti, 1964; Kantrowitz and Petschek, 1966]. However, it has been shown that intermediate shocks can be formed from continuous waves according to dissipative magnetohydrodynamics (MHD) [Wu, 1987, 1988a, b, 1990]. Thus according to the formation argument which requires that physical shocks be formed by the wave steepening process, the intermediate shocks should be considered physical. Here, intermediate shocks are studied in a two-fluid model that includes finite ion inertia dispersion and in a hybrid model in which the full ion dynamics is retained while the electrons are treated as a massless fluid. The authors show that in both models intermediate shocks can be formed through wave steepening, meaning that they are stable and possess shock structures

Hybrid quantum gates between flying photon and diamond nitrogen-vacancy centers assisted by optical microcavities

Science.gov (United States)

Wei, Hai-Rui; Lu Long, Gui

2015-01-01

Hybrid quantum gates hold great promise for quantum information processing since they preserve the advantages of different quantum systems. Here we present compact quantum circuits to deterministically implement controlled-NOT, Toffoli, and Fredkin gates between a flying photon qubit and diamond nitrogen-vacancy (NV) centers assisted by microcavities. The target qubits of these universal quantum gates are encoded on the spins of the electrons associated with the diamond NV centers and they have long coherence time for storing information, and the control qubit is encoded on the polarizations of the flying photon and can be easily manipulated. Our quantum circuits are compact, economic, and simple. Moreover, they do not require additional qubits. The complexity of our schemes for universal three-qubit gates is much reduced, compared to the synthesis with two-qubit entangling gates. These schemes have high fidelities and efficiencies, and they are feasible in experiment. PMID:26271899

A coordinated two-satellite study of energetic electron precipitation events

International Nuclear Information System (INIS)

Imhof, W.L.; Nakano, G.H.; Gaines, E.E.; Reagan, J.B.

1975-01-01

A new technique for studying the spatial/temporal variations of energetic electron precipitation events is investigated. Data are presented in which precipitating electrons were measured simultaneously on two coordinated polar-orbiting satellites and the bremsstrahlung produced by the electrons precipitating into the atmosphere was observed from one of the satellites. Two electron spectrometers measuring the intensities and energy spectra of electrons of >130 keV were located on the oriented satellite 1971-089A (altitude, approx. =800 km), whereas a single similar spectrometer measuring electrons of >160 keV was located on the spinning low-altitude (approx.750 km) satellite 1972-076B. The X rays of >50 keV were measured with a 50-cm 3 germanium spectrometer placed on the 1972-076B satellite. With the coordinated data a study is made of events in which large fluctuations were observed in the precipitating energetic electron intensities. In the examples presented the satellite X ray data alone demonstrate that the spatially integrated electron influx was constant in time, and when the X ray data are combined with the direct electron measurements from the two satellites, the resulting data suggest that the major features in the flux profiles were primarily spatial in nature. The combination of X ray and electron measurements from two satellites is shown to provide an important method for studying and attempting to resolve spatial and temporal effects

Implementation of Electronic Whiteboards at Two Emergency Departments

DEFF Research Database (Denmark)

Rasmussen, Rasmus; Fleron, Benedicte Frederikke Rex; Hertzum, Morten

2010-01-01

We report from a case study of the implementation of an electronic whiteboard system at two emergency departments at Danish hospitals. The purpose of such whiteboards is to support the clinicians in maintaining an overview of the patients at the department. The electronic whiteboard system...... was designed in collaboration with clinicians from the departments, present more information, and allow some automated updating, as compared to the existing dry-erase whiteboard. Based on observations supported by interviews we describe the implementation of the whiteboard at the two emergency departments...

Technology and application of two sets of industrial electron accelerators

International Nuclear Information System (INIS)

Hua Degen

2000-01-01

The radiation industry in China Academy of Engineering Physics (CAEP) has had a big scale, and the two sets of industrial electron accelerators play important roles. The Electron Processing System (E.P.S), which was introduced in 1987, is a powerful electron accelerator. And the 10 MeV Accelerator, which is a traveling wave linear electron accelerator, has the higher electron energy. Both of the stes are equipped the driving devices under the beam, and has made a considerable economic results. This article describes the technology and application of the two electron accelerators. (author)

Detection of Protein Interactions in T3S Systems Using Yeast Two-Hybrid Analysis.

Science.gov (United States)

Nilles, Matthew L

2017-01-01

Two-hybrid systems, sometimes termed interaction traps, are genetic systems designed to find and analyze interactions between proteins. The most common systems are yeast based (commonly Saccharomyces cerevisae) and rely on the functional reconstitution of the GAL4 transcriptional activator. Reporter genes, such as the lacZ gene of Escherichia coli (encodes β-galactosidase), are placed under GAL4-dependent transcriptional control to provide quick and reliable detection of protein interactions. In this method the use of a yeast-based two-hybrid system is described to study protein interactions between components of type III secretion systems.

Multiple paternity and hybridization in two smooth-hound sharks.

Science.gov (United States)

Marino, Ilaria A M; Riginella, Emilio; Gristina, Michele; Rasotto, Maria B; Zane, Lorenzo; Mazzoldi, Carlotta

2015-08-10

Multiple paternity appears to be a common trait of elasmobranch mating systems, with its occurrence likely driven by convenience, due to females seeking to minimize the stress of male harassment. Here we use molecular markers to analyse the frequency of multiple paternity in two related viviparous sharks, Mustelus mustelus and Mustelus punctulatus. We first applied molecular methods to assign pregnant females, embryos and additional reference adults (N = 792) to one of the two species. Paternity analysis was performed using a total of 9 polymorphic microsatellites on 19 females and 204 embryos of M. mustelus, and on 13 females and 303 embryos of M. punctulatus. Multiple paternity occurs in both species, with 47% of M. mustelus and 54% of M. punctulatus litters sired by at least two fathers. Female fecundity is not influenced by multiple mating and in 56% of polyandrous litters paternity is skewed, with one male siring most of the pups. Genetic analyses also revealed hybridization between the two species, with a M. punctulatus female bearing pups sired by a M. mustelus male. The frequency of polyandrous litters in these species is consistent with aspects of their reproductive biology, such as synchronous ovulation and possible occurrence of breeding aggregations.

Electron-electron correlation in two-photon double ionization of He-like ions

Science.gov (United States)

Hu, S. X.

2018-01-01

Electron correlation plays a crucial role in quantum many-body physics ranging from molecular bonding and strong-field-induced multielectron ionization, to superconducting in materials. Understanding the dynamic electron correlation in the photoionization of relatively simple quantum three-body systems, such as He and He-like ions, is an important step toward manipulating complex systems through photoinduced processes. Here we have performed ab initio investigations of two-photon double ionization (TPDI) of He and He-like ions (L i+,B e2 + , and C4 +) exposed to intense attosecond x-ray pulses. Results from such fully correlated quantum calculations show weaker and weaker electron correlation effects in TPDI spectra as the ionic charge increases, which is opposite to the intuition that the absolute increase of correlation in the ground state should lead to more equal energy sharing in photoionization. These findings indicate that the final-state electron-electron correlation ultimately determines the energy sharing of the two ionized electrons in TPDI.

Two-dimensional electron states bound to an off-plane donor in a magnetic field

International Nuclear Information System (INIS)

Bruno-Alfonso, A; Candido, L; Hai, G-Q

2010-01-01

The states of an electron confined in a two-dimensional (2D) plane and bound to an off-plane donor impurity center, in the presence of a magnetic field, are investigated. The energy levels of the ground state and the first three excited states are calculated variationally. The binding energy and the mean orbital radius of these states are obtained as a function of the donor center position and the magnetic field strength. The limiting cases are discussed for an in-plane donor impurity (i.e. a 2D hydrogen atom) as well as for the donor center far away from the 2D plane in strong magnetic fields, which corresponds to a 2D harmonic oscillator.

Two-particle approach to the electronic structure of solids

International Nuclear Information System (INIS)

Gonis, A.

2007-01-01

Based on an extension of Hubbard's treatment of the electronic structure of correlated electrons in matter we propose a methodology that incorporates the scattering off the Coulomb interaction through the determination of a two-particle propagator. The Green function equations of motion are then used to obtain single-particle Green functions and related properties such as densities of states. The solutions of the equations of motion in two- and single-particle spaces are accomplished through applications of the coherent potential approximation. The formalism is illustrated by means of calculations for a single-band model system representing a linear arrangement of sites with nearest neighbor hopping and an one-site repulsion when two electrons of opposite spin occupy the same site in the lattice in the manner described by the so-called Hubbard Hamiltonian

Visualization of mcr mRNA in a methanogen by fluorescence in situ hybridization with an oligonucleotide probe and two-pass tyramide signal amplification (two-pass TSA-FISH).

Science.gov (United States)

Kubota, Kengo; Ohashi, Akiyoshi; Imachi, Hiroyuki; Harada, Hideki

2006-09-01

Two-pass tyramide signal amplification-fluorescence in situ hybridization (two-pass TSA-FISH) with a horseradish peroxidase (HRP)-labeled oligonucleotide probe was applied to detect prokaryotic mRNA. In this study, mRNA of a key enzyme for methanogenesis, methyl coenzyme M reductase (mcr), in Methanococcus vannielii was targeted. Applicability of mRNA-targeted probes to in situ hybridization was verified by Clone-FISH. It was observed that sensitivity of two-pass TSA-FISH was significantly higher than that of TSA-FISH, which was further increased by the addition of dextran sulphate in TSA working solution. Signals from two-pass TSA-FISH were more reliable compared to the weak, spotty signals yielded by TSA-FISH.

Hybrid flux splitting schemes for numerical resolution of two-phase flows

Energy Technology Data Exchange (ETDEWEB)

Flaatten, Tore

2003-07-01

This thesis deals with the construction of numerical schemes for approximating. solutions to a hyperbolic two-phase flow model. Numerical schemes for hyperbolic models are commonly divided in two main classes: Flux Vector Splitting (FVS) schemes which are based on scalar computations and Flux Difference Splitting (FDS) schemes which are based on matrix computations. FVS schemes are more efficient than FDS schemes, but FDS schemes are more accurate. The canonical FDS schemes are the approximate Riemann solvers which are based on a local decomposition of the system into its full wave structure. In this thesis the mathematical structure of the model is exploited to construct a class of hybrid FVS/FDS schemes, denoted as Mixture Flux (MF) schemes. This approach is based on a splitting of the system in two components associated with the pressure and volume fraction variables respectively, and builds upon hybrid FVS/FDS schemes previously developed for one-phase flow models. Through analysis and numerical experiments it is demonstrated that the MF approach provides several desirable features, including (1) Improved efficiency compared to standard approximate Riemann solvers, (2) Robustness under stiff conditions, (3) Accuracy on linear and nonlinear phenomena. In particular it is demonstrated that the framework allows for an efficient weakly implicit implementation, focusing on an accurate resolution of slow transients relevant for the petroleum industry. (author)

Alternative Fuels Data Center: Hybrid Electric Vehicles

Science.gov (United States)

. A wide variety of hybrid electric vehicle models is currently available. Although HEVs are often -go traffic), further improving fuel economy. Mild hybrid systems cannot power the vehicle using Hybrid Electric Vehicles to someone by E-mail Share Alternative Fuels Data Center: Hybrid Electric

A new method for solving the two-center problem with relativistic potentials

International Nuclear Information System (INIS)

Gareev, F.A.; Gizzatkulov, M.Ch.

1977-01-01

A method has been proposed for the solution of the two-center problem with realistic potentials. It consists of two steps: first, a separable approximation to the single particle potentials is made and then the two-center problem with these separable potentials is solved exactly. The only approximations are introduced at the first stage in a well controllable way. As an example, we have calculated the single-particle energies and wave functions in the field of two 16 O like the Woods-Saxon potentials as functions of their distance R

Nonadiabatic two-electron transfer mediated by an irregular bridge

International Nuclear Information System (INIS)

Petrov, E.G.; Shevchenko, Ye.V.; May, V.

2004-01-01

Nonadiabatic two-electron transfer (TET) mediated by a linear molecular bridge is studied theoretically. Special attention is put on the case of a irregular distribution of bridge site energies as well as on the inter-site Coulomb interaction. Based on the unified description of electron transfer reactions [J. Chem. Phys. 115 (2001) 7107] a closed set of kinetic equations describing the TET process is derived. A reduction of this set to a single exponential donor-acceptor (D-A) TET is performed together with a derivation of an overall D-A TET rate. The latter contains a contribution of the stepwise as well as of the concerted route of D-A TET. The stepwise contribution is determined by two single-electron steps each of them associated with a sequential and a superexchange pathway. A two-electron unistep superexchange transition between the D and A forms the concerted contribution to the overall rate. Both contributions are analyzed in their dependency on the bridge length. The irregular distribution of the bridge site energies as well as the influence of the Coulomb interaction facilitates the D-A TET via a modification of the stepwise and the concerted part of the overall rate. At low temperatures and for short bridges with a single or two units the concerted contribution exceeds the stepwise contribution. If the bridge contains more than two units, the stepwise contribution dominates the overall rate

A scaling analysis of electronic localization in two-dimensional random media

International Nuclear Information System (INIS)

Ye Zhen

2003-01-01

By an improved scaling analysis, we suggest that there may appear two possibilities concerning the electronic localization in two-dimensional random media. The first is that all electronic states are localized in two dimensions, as conjectured previously. The second possibility is that electronic behaviors in two- and three-dimensional random systems are similar, in agreement with a recent calculation based on a direct calculation of the conductance with the use of the Kubo formula. In this case, non-localized states are possible in two dimensions, and have some peculiar properties. A few predictions are proposed. Moreover, the present analysis accommodates results from the previous scaling analysis

Two-dimensional electronic femtosecond stimulated Raman spectroscopy

Directory of Open Access Journals (Sweden)

Ogilvie J.P.

2013-03-01

Full Text Available We report two-dimensional electronic spectroscopy with a femtosecond stimulated Raman scattering probe. The method reveals correlations between excitation energy and excited state vibrational structure following photoexcitation. We demonstrate the method in rhodamine 6G.

Investigation of thermodynamic performances for two solar-biomass hybrid combined cycle power generation systems

International Nuclear Information System (INIS)

Liu, Qibin; Bai, Zhang; Wang, Xiaohe; Lei, Jing; Jin, Hongguang

2016-01-01

Highlights: • Two solar-biomass hybrid combined cycle power generation systems are proposed. • The characters of the two proposed systems are compared. • The on-design and off-design properties of the system are numerically investigated. • The favorable performances of thermochemical hybrid routine are validated. - Abstract: Two solar-biomass hybrid combined cycle power generation systems are proposed in this work. The first system employs the thermochemical hybrid routine, in which the biomass gasification is driven by the concentrated solar energy, and the gasified syngas as a solar fuel is utilized in a combined cycle for generating power. The second system adopts the thermal integration concept, and the solar energy is directly used to heat the compressed air in the topping Brayton cycle. The thermodynamic performances of the developed systems are investigated under the on-design and off-design conditions. The advantages of the hybrid utilization technical mode are demonstrated. The solar energy can be converted and stored into the chemical fuel by the solar-biomass gasification, with the net solar-to-fuel efficiency of 61.23% and the net solar share of 19.01% under the specific gasification temperature of 1150 K. Meanwhile, the proposed system with the solar thermochemical routine shows more favorable behaviors, the annual system overall energy efficiency and the solar-to-electric efficiency reach to 29.36% and 18.49%, while the with thermal integration concept of 28.03% and 15.13%, respectively. The comparison work introduces a promising approach for the efficient utilization of the abundant solar and biomass resources in the western China, and realizes the mitigation of CO_2 emission.

Hall field-induced magnetoresistance oscillations of a two-dimensional electron system

International Nuclear Information System (INIS)

Kunold, A.; Torres, M.

2008-01-01

We develop a model of the nonlinear response to a dc electrical current of a two-dimensional electron system (2DES) placed on a magnetic field. Based on the exact solution to the Schroedinger equation in arbitrarily strong electric and magnetic fields, and separating the relative and guiding center coordinates, a Kubo-like formula for the current is worked out as a response to the impurity scattering. Self-consistent expressions determine the longitudinal and Hall components of the electric field in terms of the dc current. The differential resistivity displays strong Hall field-induced oscillations, in agreement with the main features of the phenomenon observed in recent experiments

Evaluation of energy requirements for all-electric range of plug-in hybrid electric two-wheeler

International Nuclear Information System (INIS)

Amjad, Shaik; Rudramoorthy, R.; Neelakrishnan, S.; Sri Raja Varman, K.; Arjunan, T.V.

2011-01-01

Recently plug-in hybrid electric vehicles (PHEVs) are emerging as one of the promising alternative to improve the sustainability of transportation energy and air quality especially in urban areas. The all-electric range in PHEV design plays a significant role in sizing of battery pack and cost. This paper presents the evaluation of battery energy and power requirements for a plug-in hybrid electric two-wheeler for different all-electric ranges. An analytical vehicle model and MATLAB simulation analysis has been discussed. The MATLAB simulation results estimate the impact of driving cycle and all-electric range on energy capacity, additional mass and initial cost of lead-acid, nickel-metal hydride and lithium-ion batteries. This paper also focuses on influence of cycle life on annual cost of battery pack and recommended suitable battery pack for implementing in plug-in hybrid electric two-wheelers. -- Research highlights: → Evaluates the battery energy and power requirements for a plug-in hybrid electric two-wheeler. → Simulation results reveal that the IDC demand more energy and cost of battery compared to ECE R40. → If cycle life is considered, the annual cost of Ni-MH battery pack is lower than lead-acid and Li-ion.

Two-center interference effects in (e, 2e) ionization of H2 and CO2 at large momentum transfer

Science.gov (United States)

Yamazaki, Masakazu; Nakajima, Isao; Satoh, Hironori; Watanabe, Noboru; Jones, Darryl; Takahashi, Masahiko

2015-09-01

In recent years, there has been considerable interest in understanding quantum mechanical interference effects in molecular ionization. Since this interference appears as a consequence of coherent electron emission from the different molecular centers, it should depend strongly on the nature of the ionized molecular orbital. Such molecular orbital patterns can be investigated by means of binary (e, 2e) spectroscopy, which is a kinematically-complete electron-impact ionization experiment performed under the high-energy Bethe ridge conditions. In this study, two-center interference effects in the (e, 2e) cross sections of H2 and CO2 at large momentum transfer are demonstrated with a high-statistics experiment, in order to elucidate the relationship between molecular orbital patterns and the interference structure. It is shown that the two-center interference is highly sensitive to the phase, spatial pattern, symmetry of constituent atomic orbital, and chemical bonding nature of the molecular orbital. This work was partially supported by Grant-in-Aids for Scientific Research (S) (No. 20225001) and for Young Scientists (B) (No. 21750005) from the Ministry of Education, Culture, Sports, Science and Technology.

Dynamical localization of two electrons in triple-quantum-dot shuttles

International Nuclear Information System (INIS)

Qu, Jinxian; Duan, Suqing; Yang, Ning

2012-01-01

The dynamical localization phenomena in two-electron quantum-dot shuttles driven by an ac field have been investigated and analyzed by the Floquet theory. The dynamical localization occurs near the anti-crossings in Floquet eigenenergy spectrum. The oscillation of the quantum-dot shuttles may increase the possibility of the dynamical localization. Especially, even if the two electrons are initialized in two neighbor dots, they can be localized there for appropriate intensity of the driven field. The studies may help the understanding of dynamical localization in electron shuttles and expand the application potential of nanoelectromechanical devices. -- Highlights: ► The dynamical localization in electron shuttle is studied by Floquet theory. ► There is a relation between quasi-energy anti-crossings and dynamical localization. ► The oscillation of quantum dot increases the dynamical localization. ► Even the electrons are initialized in different dots, the localization can occur.

Quantum chaos in the two-center shell model

Energy Technology Data Exchange (ETDEWEB)

Milek, B; Noerenberg, W; Rozmej, P [Gesellschaft fuer Schwerionenforschung m.b.H., Darmstadt (Germany, F.R.)

1989-11-01

Within an axially symmetric two-center shell model single-particle levels with {Omega}=1/2 are analyzed with respect to their level-spacing distributions and avoided level crossings as functions of the shape parameters. Only for shapes sufficiently far from any additional symmetry, ideal Wigner distributions are found as signature for quantum chaos. (orig.).

Quantum chaos in the two-center shell model

Energy Technology Data Exchange (ETDEWEB)

Milek, B; Noerenberg, W; Rozmej, P

1989-03-01

Within an axially symmetric two-center shell model single-particle levels with ..cap omega.. = 1/2 are analyzed with respect to their level-spacing distributions and avoided level crossings as functions of the shape parameters. Only for shapes sufficiently far from any additional symmetry, ideal Wigner distributions are found as signature for quantum chaos.

Two dimensional hybrid simulation of a curved bow shock

International Nuclear Information System (INIS)

Thomas, V.A.; Winske, D.

1990-01-01

Results are presented from two dimensional hybrid simulations of curved collisionless supercritical shocks, retaining both quasi-perpendicular and quasi-parallel sections of the shock in order to study the character and origin of the foreshock ion population. The simulations demonstrate that the foreshock ion population is dominated by ions impinging upon the quasi-parallel side of the shock, while nonlocal transport from the quasi-perpendicular side of the shock into the foreshock region is minimal. Further, it is shown that the ions gain energy by drifting significantly in the direction of the convection electric field through multiple shock encounters

Two-dimensional optimization of free-electron-laser designs

Science.gov (United States)

Prosnitz, D.; Haas, R.A.

1982-05-04

Off-axis, two-dimensional designs for free electron lasers are described that maintain correspondence of a light beam with a synchronous electron at an optimal transverse radius r > 0 to achieve increased beam trapping efficiency and enhanced laser beam wavefront control so as to decrease optical beam diffraction and other deleterious effects.

Quantum Electronic Matter in Two Dimensions

Energy Technology Data Exchange (ETDEWEB)

Eisenstein, James [California Inst. of Technology (CalTech), Pasadena, CA (United States)

2015-01-27

Most often, the electrical properties of a material are described as either "conducting" or "insulating". Copper, everyone knows, is a good conductor. It is the foundation of the electrical infrastructure of the nation. Glass, on the other hand, is an excellent insulator. But do these two words describe all the possibilities? The answer is emphatically no, and the basic subject of the research funded by this grant is aimed at fleshing out a more complete description of the electrical properties of materials. Many people are aware that there are also special materials called superconductors. A superconductor (e.g. aluminum when cooled to very low temperatures) is like a regular conductor except that it conducts electricity with no energy loss at all. Ordinary metals get hot when current flows through them; witness the toaster in your kitchen. In a superconductor something very special is going on: The electrons in the metal don't behave individually as they do in an ordinary conductor. Instead they act collectively. It is this collective aspect that makes superconductors so interesting to physicists. So now we have metals, insulators and superconductors. Is there anything else? We now know the answer is yes. In this research we examine special conducting materials, ones in which the mobile electrons are confined to move on a plane surface (as opposed to motion in all three directions). Examples of such "2D" materials include electrons confined to the interface between two otherwise insulating materials (as in the so-called "semiconductor heterostructures" used here) and the single atomic layer of carbon atoms now known as "graphene". Materials like these are not just museum curiosities; each of the billions of transistors in every smart-phone has a 2D electron system in it. In the work supported by this grant, the focus is on both collective conducting states in semiconductor heterostructures and on the conducting properties of graphene and its few

Two-pulse laser control of nuclear and electronic motion

DEFF Research Database (Denmark)

Grønager, Michael; Henriksen, Niels Engholm

1997-01-01

We discuss an explicitly time-dependent two-pulse laser scheme for controlling where nuclei and electrons are going in unimolecular reactions. We focus on electronic motion and show, with HD+ as an example, that one can find non-stationary states where the electron (with some probability...

Electron gun for formation of two high-current beams

International Nuclear Information System (INIS)

Borisov, A.R.; Zherlitsyn, A.G.; Mel'nikov, G.V.; Shtejn, Yu.G.

1982-01-01

The design of the ''Tonus'' accelerator electron gun for formation of two high-current beams aiming at the production of the maximum beam power and density is described. The results of investigation of two modes of beam formation are presented. In the first variant the beams were produced by means of two plane diodes with 40 mm diameter cathodes made of stainless steel and anodes made of 50 μm thick titanium foil. In the second variant the beams were formed by means of two coaxial diodes with magnetic insulation. In one diode the cathode diameter equals to 74 mm, the anode diameter - 92 mm, in the other diode 16 and 44 mm respectively. Current redistribution in the diodes and its effect on accelerating voltage are investigated. It is shown that the gun permits formation of synchronized two high-current beams, iaving equal electron energied. Wide range current control of both beams is possible

On the exact spectra of two electrons confined by two-dimensional quantum dots

International Nuclear Information System (INIS)

Soldatov, A.V.; Bogolubov Jr, N.N.

2005-12-01

Applicability of the method of intermediate problems to investigation of the energy spectrum and eigenstates of a two- electron two-dimensional quantum dot (QD) formed by a parabolic confining potential is discussed. It is argued that the method of intermediate problems, which provides convergent improvable lower bound estimates for eigenvalues of linear half-bound Hermitian operators in Hilbert space, can be fused with the classical Rayleigh-Ritz variational method and stochastic variational method thus providing an efficient tool of verification of the results obtained so far by various analytical and numerical methods being of current usage for studies of quantum dot models. (author)

Magneto-transport studies on curved two-dimensional electron gases in InGaAs-microscrolls

International Nuclear Information System (INIS)

Schumacher, O.

2007-01-01

In this thesis magneto-resistance studies on evenly curved two-dimensional electron systems in cylindric geometry are presented and discussed. A principle first introduced by Prinz and co-workers in 1998 enables us to roll up thin semiconductor layer systems by taking advantage of internal elastic strain. The radius of such a semiconductor tube can be adjusted ranging from a few nanometers up to several micrometers. The tubes' shape and place on the substrate can be defined by lithographic methods which are presented in this work. Furthermore, we show rolled-up structures containing a two-dimensional electron system in the tube wall. With a special lithographic procedure we are able to structure, to contact and to roll up these 2D-electron-gases in Hall geometry. As a result, a cylindric two-dimensional electron system is produced, which experiences a modulation of the perpendicular magnetic field component. The radius of curvature of our structures is about 10 μm, the carrier mobility is optimized to values up to 125,000 cm 2 /Vs. In transport experiments on curved Hall bars containing two dimensional electron systems two Hall bar orientations, with respect to the curvature, may be distinguished. In this work both orientations, i.e. with a Hall bar along the tube curvature as well as a Hall bar along the tube axis, are presented and discussed. Measurements on Hall bars along the curvature show signatures in the longitudinal resistance, which can be understood with the help of the Landauer-Buettiker-formalism and the model of magnetic barriers. For Hall bars oriented along the tube axis the perpendicular magnetic field component averaged over the width of the bar defines the minimum position of the Shubnikov-de Haas-oscillations as well as the slope of the Hall resistance. Furthermore, measurements on so-called van the Pauw-lamellas are presented. In this geometry the magneto-resistance shows a slope which refers to highly mobile conditions at the zero crossing of

Two-dimensional and relativistic effects in lower-hybrid current drive

International Nuclear Information System (INIS)

Hewett, D.; Hizanidis, K.; Krapchev, V.; Bers, A.

1983-06-01

We present new numerical and analytic solutions of the two-dimensional Fokker-Planck equation supplemented by a parallel quasilinear diffusion term. The results show a large enhancement of the perpendicular temperature of both the electrons resonant with the applied RF fields and the more energetic electrons in the tail. Both the RF-generated current and power dissipated are substantially increased by the perpendicular energy broadening in the resonant region. In the presence of a small DC electric field the RF current generated is very much enhanced, much more than in a simple additive fashion. In addition, we present a relativistic formulation of the two-dimensional Fokker-Planck quasilinear equation. From conservation equations, based upon this formulation, we derive the characteristics of RF current drive with energetic electrons. These show how the RF-driven current and its figure of merit (I/P/sub d/) increase with the energy of the current-carrying electrons, and that their perpendicular, random momentum must also increase

Polymer-metal hybrid transparent electrodes for flexible electronics

Science.gov (United States)

Kang, Hongkyu; Jung, Suhyun; Jeong, Soyeong; Kim, Geunjin; Lee, Kwanghee

2015-03-01

Despite nearly two decades of research, the absence of ideal flexible and transparent electrodes has been the largest obstacle in realizing flexible and printable electronics for future technologies. Here we report the fabrication of ‘polymer-metal hybrid electrodes’ with high-performance properties, including a bending radius 95% and a sheet resistance solar cells that exhibit a high power conversion efficiency of 10% and polymer light-emitting diodes that can outperform those based on transparent conducting oxides.

Measurement of the two track separation capability of hybrid pixel sensors

Energy Technology Data Exchange (ETDEWEB)

Muñoz, F.J., E-mail: Francisca.MunozSanchez@manchester.ac.uk [University of Manchester (United Kingdom); Battaglia, M. [University of California, Santa Cruz, United States of America (United States); CERN, The European Organization for Nuclear Research (Switzerland); Da Vià, C. [University of Manchester (United Kingdom); La Rosa, A. [University of California, Santa Cruz, United States of America (United States); Dann, N. [University of Manchester (United Kingdom)

2017-02-11

Large Hadron Collider experiments face new challenges in Run-2 conditions due to the increased beam energy, the interest for searches of new physics signals with higher jet pT and the consequent longer decay length of heavy hadrons. In this new scenario, the capability of the innermost pixel sensors to distinguish tracks in very dense environment becomes crucial for efficient tracking and flavour tagging performance. In this work, we discuss the measurement in a test beam of the two track separation capability of hybrid pixel sensors using the interaction particles out of the collision of high energy pions on a thin copper target. With this method we are able to evaluate the effect of merged hits in the sensors under test due to tracks closer than the sensor spatial granularity in terms of collected charge, multiplicity and reconstruction efficiency. - Highlights: • Measurement of the two-track separation capability of hybrid pixel sensors. • Emulating track dense environment with a cooper target in a test beam. • Cooper target in between telescope arms to create vertices. • Validation of simulation and reconstruction algorithm for future vertex detectors. • New qualification method for pixel modules in track dense environments.

Zero- and two-dimensional hybrid carbon phosphors for high colorimetric purity white light-emission.

Science.gov (United States)

Ding, Yamei; Chang, Qing; Xiu, Fei; Chen, Yingying; Liu, Zhengdong; Ban, Chaoyi; Cheng, Shuai; Liu, Juqing; Huang, Wei

2018-03-01

Carbon nanomaterials are promising phosphors for white light emission. A facile single-step synthesis method has been developed to prepare zero- and two-dimensional hybrid carbon phosphors for the first time. Zero-dimensional carbon dots (C-dots) emit bright blue luminescence under 365 nm UV light and two-dimensional nanoplates improve the dispersity and film forming ability of C-dots. As a proof-of-concept application, the as-prepared hybrid carbon phosphors emit bright white luminescence in the solid state, and the phosphor-coated blue LEDs exhibit high colorimetric purity white light-emission with a color coordinate of (0.3308, 0.3312), potentially enabling the successful application of white emitting phosphors in the LED field.

Theory of the one- and two-dimensional electron gas

International Nuclear Information System (INIS)

Emery, V.J.

1987-01-01

Two topics are discussed: (1) the competition between 2k/sub F/ and 4k/sub F/ charge state waves in a one-dimensional electron gas and (2) a two-dimensional model of high T/sub c/ superconductivity in the oxides

Cross effects on electron-cyclotron and lower-hybrid current drive in tokamak plasmas

International Nuclear Information System (INIS)

Fidone, I.; Giruzzi, G.; Krivenski, V.; Mazzucato, E.; Ziebell, L.F.

1986-11-01

Electron cyclotron resonance current drive in a tokamak plasma in the presence of a lower hybrid tail is investigated using a 2D Fokker-Planck code. For an extraordinary mode at oblique propagation and down-shifted frequency it is shown that the efficiency of electron cyclotron current drive becomes, i) substantially greater than the corresponding efficiency of a Maxwellian plasma at the same bulk temperature, ii) equal or greater than that of the lower hybrid waves, iii) comparable with the efficiency of a Maxwellian plasma at much higher temperature. This enhancement results from a beneficial cross-effect of the two waves on the formation of the current carrying electron tail. (5 fig; 17 refs)

Investigation of the two-photon polymerisation of a Zr-based inorganic-organic hybrid material system

International Nuclear Information System (INIS)

Bhuian, B.; Winfield, R.J.; O'Brien, S.; Crean, G.M.

2006-01-01

Two-photon polymerisation of photo-sensitive materials allows the fabrication of three dimensional micro- and nano-structures for photonic, electronic and micro-system applications. However the usable process window and the applicability of this fabrication technique is significantly determined by the properties of the photo-sensitive material employed. In this study investigation of a custom inorganic-organic hybrid system, cross-linked by a two-photon induced process, is described. The material was produced by sol-gel synthesis using a silicon alkoxide species that also possessed methacrylate functionality. Stabilized zirconium alkoxide precursors were added to the precursor solution in order to reduce drying times and impart enhanced mechanical stability to deposited films. This enabled dry films to be used in the polymerisation process. A structural, optical and mechanical analysis of the optimised sol-gel material is presented. A Ti:sapphire laser with 80 MHz repetition rate, 100 fs pulse duration and 795 nm is used. The influence of both material system and laser processing parameters including: laser power, photo-initiator concentration and zirconium loading, on achievable micro-structure and size is presented

Paramagnetic centers in two phases of manganese-doped lanthanum gallate

Science.gov (United States)

Vazhenin, V. A.; Potapov, A. P.; Guseva, V. B.; Artyomov, M. Yu.

2009-05-01

An EPR study of two phases of manganese-doped lanthanum gallate (with a first-order structural transition occurring at 430 K) has revealed Gd3+, Fe3+, and Mn4+ centers at room temperature and 438 K. The parameters of spin Hamiltonians are determined for the Gd3+, Fe3+, and Mn4+ rhombohedral centers in the high-temperature phase (with no other centers found here) and for the monoclinic center Gd3+ in the low-temperature phase. Both in the orthorhombic and in the rhombohedral phase, crystallographic twins (or ferroelastic domains) are observed.

The Causes and Evolutionary Consequences of Mixed Singing in Two Hybridizing Songbird Species (Luscinia spp.)

Science.gov (United States)

Vokurková, Jana; Petrusková, Tereza; Reifová, Radka; Kozman, Alexandra; Mořkovský, Libor; Kipper, Silke; Weiss, Michael; Reif, Jiří; Dolata, Paweł T.; Petrusek, Adam

2013-01-01

Bird song plays an important role in the establishment and maintenance of prezygotic reproductive barriers. When two closely related species come into secondary contact, song convergence caused by acquisition of heterospecific songs into the birds’ repertoires is often observed. The proximate mechanisms responsible for such mixed singing, and its effect on the speciation process, are poorly understood. We used a combination of genetic and bioacoustic analyses to test whether mixed singing observed in the secondary contact zone of two passerine birds, the Thrush Nightingale (Luscinia luscinia) and the Common Nightingale (L. megarhynchos), is caused by introgressive hybridization. We analysed song recordings of both species from allopatric and sympatric populations together with genotype data from one mitochondrial and seven nuclear loci. Semi-automated comparisons of our recordings with an extensive catalogue of Common Nightingale song types confirmed that most of the analysed sympatric Thrush Nightingale males were ‘mixed singers’ that use heterospecific song types in their repertoires. None of these ‘mixed singers’ possessed any alleles introgressed from the Common Nightingale, suggesting that they were not backcross hybrids. We also analysed songs of five individuals with intermediate phenotype, which were identified as F1 hybrids between the Thrush Nightingale female and the Common Nightingale male by genetic analysis. Songs of three of these hybrids corresponded to the paternal species (Common Nightingale) but the remaining two sung a mixed song. Our results suggest that although hybridization might increase the tendency for learning songs from both parental species, interspecific cultural transmission is the major proximate mechanism explaining the occurrence of mixed singers among the sympatric Thrush Nightingales. We also provide evidence that mixed singing does not substantially increase the rate of interspecific hybridization and discuss the

A Special Family of LMM with Two Hybrid Points for Stiff ODEs ...

African Journals Online (AJOL)

Enright (1974) discussed the formulation of the second derivative LMM which was found to be stiffly stable for step number k £ 7 for the numerical solution of stiff Initial Value Problems (IVPs) in Ordinary Differential Equations (ODEs). In this paper some second derivative continuous linear multistep methods with two hybrid ...

Estimates of hybridization between two species of catostomids in the Columbia River

Energy Technology Data Exchange (ETDEWEB)

Dauble, D.D.; Buschbom, R.L.

1981-01-01

Extent of hybridization is described between two sympatric catostomids, Catostomus macrocheilus and C. columbianus, from the Hanford Reach of the Columbia River, southeastern Washington state. Estimated percentage of hybrids based on presence of intermediate meristic characters ranged from 12.4 to 14.6% of the total sucker population. Discriminant function analysis reduced subjective variability and lowered estimates of hybridization to 3.0 to 7.1%. Principal component analysis also provided evidence that the suspected hybrids were intermediate between populations of C. macrocheilus and C. columbianus. Meristic characters contributed most to all methods of treatment, with number of lateral line scales the best single criterion for species separation. Any analysis of closely related species would benefit from examination of offspring from artificial crosses and from knowledge of allopatric population characteristics. Breakdown of isolating mechanisms leading to C. macrocheilus X C. columbianus crosses may result from overlap in spawning time and incomplete habitat segregation. Morphological and coloration differences at spawning may provide a basis for species recognition, thus providing some degree of ethological isolation.

Impurity effects in two-electron coupled quantum dots: entanglement modulation

International Nuclear Information System (INIS)

Acosta Coden, Diego S; Romero, Rodolfo H; Ferrón, Alejandro; Gomez, Sergio S

2013-01-01

We present a detailed analysis of the electronic and optical properties of two-electron quantum dots with a two-dimensional Gaussian confinement potential. We study the effects of Coulomb impurities and the possibility of manipulating the entanglement of the electrons by controlling the confinement potential parameters. The degree of entanglement becomes highly modulated by both the location and charge screening of the impurity atom, resulting in two regimes: one of low entanglement and the other of high entanglement, with both of them mainly determined by the magnitude of the charge. It is shown that the magnitude of the oscillator strength of the system could provide an indication of the presence and characteristics of impurities and, therefore, the degree of entanglement. (paper)

The Economic Potential of Two Nuclear-Renewable Hybrid Energy Systems

Energy Technology Data Exchange (ETDEWEB)

Ruth, Mark [National Renewable Energy Lab. (NREL), Golden, CO (United States); Cutler, Dylan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Flores-Espino, Francisco [National Renewable Energy Lab. (NREL), Golden, CO (United States); Stark, Greg [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jenkin, Thomas [National Renewable Energy Lab. (NREL), Golden, CO (United States); Simpkins, Travis [National Renewable Energy Lab. (NREL), Golden, CO (United States); Macknick, Jordan [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-08-01

This report is one of a series of reports that investigate the technical and economic aspects of Nuclear-Renewable Hybrid Energy Systems. It provides the results of an analysis of two scenarios. The first is a Texas-synthetic gasoline scenario and the second is an Arizona-desalination scenario. The analysis focuses on the economics of the N-R HESs and how they compare to other options, including configurations without all the subsystems in each N-R HES and alternatives in which natural gas provides the energy.

Tunneling between parallel two-dimensional electron liquids

Czech Academy of Sciences Publication Activity Database

Jungwirth, Tomáš; MacDonald, A. H.

361/362, - (1996), s. 167-170 ISSN 0039-6028. [International Conference on the Electronic Properties of Two Dimensional Systems /11./. Nottingham, 07.08.1995-11.08.1995] R&D Projects: GA ČR GA202/94/1278 Grant - others:INT(XX) 9106888 Impact factor: 2.783, year: 1996

Electron capture in pseudo-two-electron systems: Ar8++He

International Nuclear Information System (INIS)

Kimura, M.; Olson, R.E.

1985-01-01

Molecular-structure calculations using the pseudopotential method have been performed on the (ArHe) 8+ system. The cross section for single-electron capture in Ar 8+ +He collisions was calculated for energies from 20 eV to 10 keV/amu. The perturbed-stationary-state method [M. Kimura, H. Sato, and R. E. Olson, Phys. Rev. A 28, 2085 (1983)], modified to include electron translation factors appropriate to two-electron systems, was used. The total cross section is relatively energy independent with a value of approximately 2.5 x 10 -15 cm 2 . The n = 4 level of Ar 7+ is found to be preferentially populated, with the 4f level being dominant

Derivation of hybrid ES cell lines from two different strains of mice

Directory of Open Access Journals (Sweden)

Ho-Tak Lau

2016-03-01

Full Text Available Parental origin-dependent expression of the imprinted genes is essential for mammalian development. Zfp57 maintains genomic imprinting in mouse embryos and ES cells. To examine the allelic expression patterns of the imprinted genes in ES cells, we obtained multiple hybrid ES clones that were directly derived from the blastocysts generated from the cross between mice on two different genetic backgrounds. The blastocyst-derived ES clones displayed largely intact DNA methylation imprint at the tested imprinted regions. These hybrid ES clones will be useful for future studies to examine the allelic expression of the imprinted genes in ES cells and their differentiated progeny.

System for cooling hybrid vehicle electronics, method for cooling hybrid vehicle electronics

Science.gov (United States)

France, David M.; Yu, Wenhua; Singh, Dileep; Zhao, Weihuan

2017-11-21

The invention provides a single radiator cooling system for use in hybrid electric vehicles, the system comprising a surface in thermal communication with electronics, and subcooled boiling fluid contacting the surface. The invention also provides a single radiator method for simultaneously cooling electronics and an internal combustion engine in a hybrid electric vehicle, the method comprising separating a coolant fluid into a first portion and a second portion; directing the first portion to the electronics and the second portion to the internal combustion engine for a time sufficient to maintain the temperature of the electronics at or below 175.degree. C.; combining the first and second portion to reestablish the coolant fluid; and treating the reestablished coolant fluid to the single radiator for a time sufficient to decrease the temperature of the reestablished coolant fluid to the temperature it had before separation.

Electronic Transport in Two-Dimensional Materials

Science.gov (United States)

Sangwan, Vinod K.; Hersam, Mark C.

2018-04-01

Two-dimensional (2D) materials have captured the attention of the scientific community due to the wide range of unique properties at nanometer-scale thicknesses. While significant exploratory research in 2D materials has been achieved, the understanding of 2D electronic transport and carrier dynamics remains in a nascent stage. Furthermore, because prior review articles have provided general overviews of 2D materials or specifically focused on charge transport in graphene, here we instead highlight charge transport mechanisms in post-graphene 2D materials, with particular emphasis on transition metal dichalcogenides and black phosphorus. For these systems, we delineate the intricacies of electronic transport, including band structure control with thickness and external fields, valley polarization, scattering mechanisms, electrical contacts, and doping. In addition, electronic interactions between 2D materials are considered in the form of van der Waals heterojunctions and composite films. This review concludes with a perspective on the most promising future directions in this fast-evolving field.

Analysis of differences in outcome of two European liver transplant centers

NARCIS (Netherlands)

Nemes, B; Polak, W; Ther, G; Hendriks, H; Kobori, L; Porte, RJ; Sarvary, E; de Jong, KP; Doros, A; Gerlei, Z; van den Berg, AP; Fehervari, [No Value; Gorog, D; Peeters, PM; Jaray, J; Slooff, MJH

Authors analyzed the differences in the outcome of two European liver transplant centers differing in case volume and experience. The first was the Transplantation and Surgical Clinic, Semmelweis University, Budapest, Hungary (SEB) and the second the University Medical Center Groningen, Groningen,

A two-center-oscillator-basis as an alternative set for heavy ion processes

International Nuclear Information System (INIS)

Tornow, V.; Reinhard, P.G.; Drechsel, D.

1977-01-01

The two-center-oscillator-basis, which is constructed from harmonic oscillator wave functions developing about two different centers, suffers from numerical problems at small center separations due to the overcompleteness of the set. In order to overcome these problems we admix higer oscillator wave functions before the orthogonalization, or antisymmetrization resp. This yields a numerically stable basis set at each center separation. The results obtained for the potential energy suface are comparable with the results of more elaborate models. (orig.) [de

A two-hybrid assay to study protein interactions within the secretory pathway.

Directory of Open Access Journals (Sweden)

Danielle H Dube

Full Text Available Interactions of transcriptional activators are difficult to study using transcription-based two-hybrid assays due to potent activation resulting in false positives. Here we report the development of the Golgi two-hybrid (G2H, a method that interrogates protein interactions within the Golgi, where transcriptional activators can be assayed with negligible background. The G2H relies on cell surface glycosylation to report extracellularly on protein-protein interactions occurring within the secretory pathway. In the G2H, protein pairs are fused to modular domains of the reporter glycosyltransferase, Och1p, and proper cell wall formation due to Och1p activity is observed only when a pair of proteins interacts. Cells containing interacting protein pairs are identified by selectable phenotypes associated with Och1p activity and proper cell wall formation: cells that have interacting proteins grow under selective conditions and display weak wheat germ agglutinin (WGA binding by flow cytometry, whereas cells that lack interacting proteins display stunted growth and strong WGA binding. Using this assay, we detected the interaction between transcription factor MyoD and its binding partner Id2. Interfering mutations along the MyoD:Id2 interaction interface ablated signal in the G2H assay. Furthermore, we used the G2H to detect interactions of the activation domain of Gal4p with a variety of binding partners. Finally, selective conditions were used to enrich for cells encoding interacting partners. The G2H detects protein-protein interactions that cannot be identified via traditional two-hybrid methods and should be broadly useful for probing previously inaccessible subsets of the interactome, including transcriptional activators and proteins that traffic through the secretory pathway.

Two-dimensional electronic spectroscopy with birefringent wedges

Energy Technology Data Exchange (ETDEWEB)

Réhault, Julien; Maiuri, Margherita; Oriana, Aurelio; Cerullo, Giulio [IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

2014-12-15

We present a simple experimental setup for performing two-dimensional (2D) electronic spectroscopy in the partially collinear pump-probe geometry. The setup uses a sequence of birefringent wedges to create and delay a pair of phase-locked, collinear pump pulses, with extremely high phase stability and reproducibility. Continuous delay scanning is possible without any active stabilization or position tracking, and allows to record rapidly and easily 2D spectra. The setup works over a broad spectral range from the ultraviolet to the near-IR, it is compatible with few-optical-cycle pulses and can be easily reconfigured to two-colour operation. A simple method for scattering suppression is also introduced. As a proof of principle, we present degenerate and two-color 2D spectra of the light-harvesting complex 1 of purple bacteria.

Two electron response to an intense x-ray free electron laser pulse

International Nuclear Information System (INIS)

Moore, L R; Parker, J S; Meharg, K J; Armstrong, G S J; Taylor, K T

2009-01-01

New x-ray free electron lasers (FELs) promise an ultra-fast ultra-intense regime in which new physical phenomena, such as double core hole formation in at atom, should become directly observable. Ahead of x-ray FEL experiments, an initial key task is to theoretically explore such fundamental laser-atom interactions and processes. To study the response of a two-electron positive ion to an intense x-ray FEL pulse, our theoretical approach is a direct numerical integration, incorporating non-dipole Hamiltonian terms, of the full six-dimensional time-dependent Schroedinger equation. We present probabilities of double K-shell ionization in the two-electron positive ions Ne 8+ and Ar 16+ exposed to x-ray FEL pulses with frequencies in the range 50 au to 300 au and intensities in the range 10 17 to 10 22 W/cm 2 .

Hybrid male sterility in rice controlled by interaction between divergent alleles of two adjacent genes.

Science.gov (United States)

Long, Yunming; Zhao, Lifeng; Niu, Baixiao; Su, Jing; Wu, Hao; Chen, Yuanling; Zhang, Qunyu; Guo, Jingxin; Zhuang, Chuxiong; Mei, Mantong; Xia, Jixing; Wang, Lan; Wu, Haibin; Liu, Yao-Guang

2008-12-02

Sterility is common in hybrids between divergent populations, such as the indica and japonica subspecies of Asian cultivated rice (Oryza sativa). Although multiple loci for plant hybrid sterility have been identified, it remains unknown how alleles of the loci interact at the molecular level. Here we show that a locus for indica-japonica hybrid male sterility, Sa, comprises two adjacent genes, SaM and SaF, encoding a small ubiquitin-like modifier E3 ligase-like protein and an F-box protein, respectively. Most indica cultivars contain a haplotype SaM(+)SaF(+), whereas all japonica cultivars have SaM(-)SaF(-) that diverged by nucleotide variations in wild rice. Male semi-sterility in this heterozygous complex locus is caused by abortion of pollen carrying SaM(-). This allele-specific gamete elimination results from a selective interaction of SaF(+) with SaM(-), a truncated protein, but not with SaM(+) because of the presence of an inhibitory domain, although SaM(+) is required for this male sterility. Lack of any one of the three alleles in recombinant plants does not produce male sterility. We propose a two-gene/three-component interaction model for this hybrid male sterility system. The findings have implications for overcoming male sterility in inter-subspecific hybrid rice breeding.

Determining the static electronic and vibrational energy correlations via two-dimensional electronic-vibrational spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Dong, Hui; Lewis, Nicholas H. C.; Oliver, Thomas A. A.; Fleming, Graham R., E-mail: grfleming@lbl.gov [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, Californial 94720 (United States); Kavli Energy NanoSciences Institute at Berkeley, Berkeley, California 94720 (United States)

2015-05-07

Changes in the electronic structure of pigments in protein environments and of polar molecules in solution inevitably induce a re-adaption of molecular nuclear structure. Both changes of electronic and vibrational energies can be probed with visible or infrared lasers, such as two-dimensional electronic spectroscopy or vibrational spectroscopy. The extent to which the two changes are correlated remains elusive. The recent demonstration of two-dimensional electronic-vibrational (2DEV) spectroscopy potentially enables a direct measurement of this correlation experimentally. However, it has hitherto been unclear how to characterize the correlation from the spectra. In this paper, we present a theoretical formalism to demonstrate the slope of the nodal line between the excited state absorption and ground state bleach peaks in the spectra as a characterization of the correlation between electronic and vibrational transition energies. We also show the dynamics of the nodal line slope is correlated to the vibrational spectral dynamics. Additionally, we demonstrate the fundamental 2DEV spectral line-shape of a monomer with newly developed response functions.

Design of a Novel Two-Component Hybrid Dermal Scaffold for the Treatment of Pressure Sores.

Science.gov (United States)

Sharma, Vaibhav; Kohli, Nupur; Moulding, Dale; Afolabi, Halimat; Hook, Lilian; Mason, Chris; García-Gareta, Elena

2017-11-01

The aim of this study is to design a novel two-component hybrid scaffold using the fibrin/alginate porous hydrogel Smart Matrix combined to a backing layer of plasma polymerized polydimethylsiloxane (Sil) membrane to make the fibrin-based dermal scaffold more robust for the treatment of the clinically challenging pressure sores. A design criteria are established, according to which the Sil membranes are punched to avoid collection of fluid underneath. Manual peel test shows that native silicone does not attach to the fibrin/alginate component while the plasma polymerized silicone membranes are firmly bound to fibrin/alginate. Structural characterization shows that the fibrin/alginate matrix is intact after the addition of the Sil membrane. By adding a Sil membrane to the original fibrin/alginate scaffold, the resulting two-component scaffolds have a significantly higher shear or storage modulus G'. In vitro cell studies show that dermal fibroblasts remain viable, proliferate, and infiltrate the two-component hybrid scaffolds during the culture period. These results show that the design of a novel two-component hybrid dermal scaffold is successful according to the proposed design criteria. To the best of the authors' knowledge, this is the first study that reports the combination of a fibrin-based scaffold with a plasma-polymerized silicone membrane. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electron-phonon heat exchange in quasi-two-dimensional nanolayers

Science.gov (United States)

Anghel, Dragos-Victor; Cojocaru, Sergiu

2017-12-01

We study the heat power P transferred between electrons and phonons in thin metallic films deposited on free-standing dielectric membranes. The temperature range is typically below 1 K, such that the wavelengths of the excited phonon modes in the system is large enough so that the picture of a quasi-two-dimensional phonon gas is applicable. Moreover, due to the quantization of the components of the electron wavevectors perpendicular to the metal film's surface, the electrons spectrum forms also quasi two-dimensional sub-bands, as in a quantum well (QW). We describe in detail the contribution to the electron-phonon energy exchange of different electron scattering channels, as well as of different types of phonon modes. We find that heat flux oscillates strongly with thickness of the film d while having a much smoother variation with temperature (Te for the electrons temperature and Tph for the phonons temperature), so that one obtains a ridge-like landscape in the two coordinates, (d, Te) or (d, Tph), with crests and valleys aligned roughly parallel to the temperature axis. For the valley regions we find P ∝ Te3.5 - Tph3.5. From valley to crest, P increases by more than one order of magnitude and on the crests P cannot be represented by a simple power law. The strong dependence of P on d is indicative of the formation of the QW state and can be useful in controlling the heat transfer between electrons and crystal lattice in nano-electronic devices. Nevertheless, due to the small value of the Fermi wavelength in metals, the surface imperfections of the metallic films can reduce the magnitude of the oscillations of P vs. d, so this effect might be easier to observe experimentally in doped semiconductors.

A Hybrid System Based on an Electronic Nose Coupled with an Electronic Tongue for the Characterization of Moroccan Waters

Directory of Open Access Journals (Sweden)

Z. Haddi

2014-05-01

Full Text Available A hybrid multisensor system combined with multivariate analysis was applied to the characterization of different kinds of Moroccan waters. The proposed hybrid system based on an electronic nose coupled with an electronic tongue consisted of metal oxide semiconductors and potentiometric sensors respectively. Five Taguchi Gas Sensors were implemented in the electronic nose for the discrimination between mineral, natural, sparkling, river and tap waters. Afterwards, the electronic tongue, based on series of Ion-Selective-Electrodes was applied to the analysis of the same waters. Multisensor responses obtained from the waters were processed by two chemometrics: Principal Component Analysis (PCA and Linear Discriminant Analysis (LDA. PCA results using electronic nose data depict all of the potable water samples in a separate group from the samples that were originated from river. Furthermore, PCA and LDA analysis on electronic tongue data permitted clear and rapid recognizing of the different waters due to the concentration changes of the chemical parameters from source to another.

Flat microwave photonic filter based on hybrid of two filters

International Nuclear Information System (INIS)

Qi, Chunhui; Pei, Li; Ning, Tigang; Li, Jing; Gao, Song

2010-01-01

A new microwave photonic filter (MPF) hybrid of two filters that can realize both multiple taps and a flat bandpass or bandstop response is presented. Based on the phase character of a Mach–Zehnder modulator (MZM), a two taps finite impulse response (FIR) filter is obtained as the first part. The second part is obtained by taking full advantage of the wavelength selectivity of the fiber Bragg grating (FBG) and the gain of a erbium-doped fiber (EDF). Combining the two filters, the flat bandpass or bandstop response is realized by changing the coupler's factor k, the reflectivity of FBG1 R 1 or the gain of the EDF g. Optimizing the system parameters, a flat bandpass response with amplitude depth of more than 45 dB is obtained at k = 0.5, R 1 = 0.33, g = 10, and a flat bandstop response is also obtained at k = 0.4, R 1 = 0.5, g = 2. In addition, the free-spectral range (FSR) can be controlled by changing the length of the EDF and the length difference between two MZMs. The method is proved feasible by some experiments. Such a method offers realistic solutions to support future radio-frequency (RF) optical communication systems

Optical-phonon-induced frictional drag in coupled two-dimensional electron gases

DEFF Research Database (Denmark)

Hu, Ben Yu-Kuang

1998-01-01

The role of optical phonons in frictional drag between two adjacent but electrically isolated two-dimensional electron gases is investigated. Since the optical phonons in III-V materials have a considerably larger coupling to electrons than acoustic phonons (which are the dominant drag mechanism ...

Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems

NARCIS (Netherlands)

Ferrari, A.C.; Dekker, C.; Vandersypen, L.M.K.; Van Der Zant, H.S.J.

2014-01-01

We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European

Wide prevalence of hybridization in two sympatric grasshopper species may be shaped by their relative abundances.

Science.gov (United States)

Rohde, Katja; Hau, Yvonne; Weyer, Jessica; Hochkirch, Axel

2015-09-16

Hybridization between species is of conservation concern as it might threaten the genetic integrity of species. Anthropogenic factors can alter hybridization dynamics by introducing new potentially hybridizing species or by diminishing barriers to hybridization. This may even affect sympatric species pairs through environmental change, which so far has received little attention. We studied hybridization prevalence and the underlying behavioral mechanisms in two sympatric grasshopper species, a rare specialist (Chorthippus montanus) and a common generalist (Chorthippus parallelus). We conducted a mate choice experiment with constant intraspecific density and varying heterospecific density, i.e. varying relative frequency of both species. Mate choice was frequency-dependent in both species with a higher risk of cross-mating with increasing heterospecific frequency, while conspecific mating increased linearly with increasing conspecific density. This illustrates that reproductive barriers could be altered by environmental change, if the relative frequency of species pairs is affected. Moreover, we performed a microsatellite analysis to detect hybridization in twelve syntopic populations (and four allotopic populations). Hybrids were detected in nearly all syntopic populations with hybridization rates reaching up to 8.9 %. Genetic diversity increased for both species when hybrids were included in the data set, but only in the common species a positive correlation between hybridization rate and genetic diversity was detected. Our study illustrates that the relative frequency of the two species strongly determines the effectiveness of reproductive barriers and that even the more choosy species (Ch. montanus) may face a higher risk of hybridization if population size decreases and its relative frequency becomes low compared to its sister species. The asymmetric mate preferences of both species may lead to quasi-unidirectional gene flow caused by unidirectional

Hyperpolarizabilities of one and two electron ions under strongly coupled plasma

International Nuclear Information System (INIS)

Sen, Subhrangsu; Mandal, Puspajit; Kumar Mukherjee, Prasanta; Fricke, Burkhard

2013-01-01

Systematic investigations on the hyperpolarizabilities of hydrogen and helium like ions up to nuclear charge Z = 7 under strongly coupled plasma environment have been performed. Variation perturbation theory has been adopted to evaluate such properties for the one and two electron systems. For the two electron systems coupled Hartree-Fock theory, which takes care of partial electron correlation effects, has been utilised. Ion sphere model of the strongly coupled plasma, valid for ionic systems only, has been adopted for estimating the effect of plasma environment on the hyperpolarizability. The calculated free ion hyperpolarizability for all the systems is in good agreement with the existing data. Under confinement hyperpolarizabilities of one and two electron ions show interesting trend with respect to plasma coupling strength.

Gonadal expression of aromatase and estrogen receptor alpha genes in two races of Tunisian mice and their hypofertile hybrids.

Science.gov (United States)

Saïd, Lamia; Delalande, Christelle; Britton-Davidian, Janice; Saïd, Khaled; Saad, Ali; Carreau, Serge

2007-07-01

House mice (Mus musculus domesticus) in Tunisia consists of two races, one carries the 40-acrocentric standard karyotypes and the other one is a robertsonian race (2n=22) homozygous for nine centric fusions (Rb). The F1 hybrids between the two chromosomal races showed a significant decrease in reproductive success and litter size. Such results can be related to the formation of meiotic trivalent in the hybrids leading to the production of viable aneuploid gametes and post-zygotic elimination of embryos due to chromosomal non disjunction events at meiosis. Moreover, testicular histology of F1 and backcross males showed in some cases a breakdown in spermatogenesis. In both females and males, androgens but also estrogens play an important role in gametogenesis. In this study, we have studied aromatase and estrogen receptor alpha (ERalpha) gene expression in the gonads of the two parental races and their chromosomal hybrids. The results showed that aromatase and ERalpha mRNAs are expressed in hybrid males of inter-racial crosses (female22Rb x male40Std and female40Std x male22Rb) and in hybrid females of inter-racial crosses (female22Rb x male40Std) as in the two parental races. However, in hybrid females of inter-racial crosses (female40Std x male22Rb) the amount of aromatase transcripts decreased sharply suggesting that this gene is involved in the breakdown of hybrid fertility in females, but not in males. However, in hybrid males, a putative post-translational modification of this enzyme, in terms of activity, should be verified.

Two-electron Rabi oscillations in real-time time-dependent density-functional theory

International Nuclear Information System (INIS)

Habenicht, Bradley F.; Tani, Noriyuki P.; Provorse, Makenzie R.; Isborn, Christine M.

2014-01-01

We investigate the Rabi oscillations of electrons excited by an applied electric field in several simple molecular systems using time-dependent configuration interaction (TDCI) and real-time time-dependent density-functional theory (RT-TDDFT) dynamics. While the TDCI simulations exhibit the expected single-electron Rabi oscillations at a single resonant electric field frequency, Rabi oscillations in the RT-TDDFT simulations are a two-electron process. The existence of two-electron Rabi oscillations is determined both by full population inversion between field-free molecular orbitals and the behavior of the instantaneous dipole moment during the simulations. Furthermore, the Rabi oscillations in RT-TDDFT are subject to an intensity threshold of the electric field, below which Rabi oscillations do not occur and above which the two-electron Rabi oscillations occur at a broad range of frequencies. It is also shown that at field intensities near the threshold intensity, the field frequency predicted to induce Rabi oscillations by linear response TDDFT only produces detuned Rabi oscillations. Instead, the field frequency that yields the full two-electron population inversion and Rabi oscillation behavior is shown to be the average of single-electron transition frequencies from the ground S 0 state and the doubly-excited S 2 state. The behavior of the two-electron Rabi oscillations is rationalized via two possible models. The first model is a multi-photon process that results from the electric field interacting with the three level system such that three level Rabi oscillations may occur. The second model suggests that the mean-field nature of RT-TDDFT induces paired electron propagation

Superconductivity in engineered two-dimensional electron gases

Science.gov (United States)

Chubukov, Andrey V.; Kivelson, Steven A.

2017-11-01

We consider Kohn-Luttinger mechanism for superconductivity in a two-dimensional electron gas confined to a narrow well between two grounded metallic planes with two occupied subbands with Fermi momenta kF L>kF S . On the basis of a perturbative analysis, we conclude that non-s -wave superconductivity emerges even when the bands are parabolic. We analyze the conditions that maximize Tc as a function of the distance to the metallic planes, the ratio kF L/kF S , and rs, which measures the strength of Coulomb correlations. The largest attraction is in p -wave and d -wave channels, of which p wave is typically the strongest. For rs=O (1 ) we estimate that the dimensionless coupling λ ≈10-1 , but it likely continues increasing for larger rs (where we lose theoretical control).

Terahertz Plasma Waves in Two Dimensional Quantum Electron Gas with Electron Scattering

International Nuclear Information System (INIS)

Zhang Liping

2015-01-01

We investigate the Terahertz (THz) plasma waves in a two-dimensional (2D) electron gas in a nanometer field effect transistor (FET) with quantum effects, the electron scattering, the thermal motion of electrons and electron exchange-correlation. We find that, while the electron scattering, the wave number along y direction and the electron exchange-correlation suppress the radiation power, but the thermal motion of electrons and the quantum effects can amplify the radiation power. The radiation frequency decreases with electron exchange-correlation contributions, but increases with quantum effects, the wave number along y direction and thermal motion of electrons. It is worth mentioning that the electron scattering has scarce influence on the radiation frequency. These properties could be of great help to the realization of practical THz plasma oscillations in nanometer FET. (paper)

Two electron response to an intense x-ray free electron laser pulse

Energy Technology Data Exchange (ETDEWEB)

Moore, L R; Parker, J S; Meharg, K J; Armstrong, G S J; Taylor, K T, E-mail: l.moore@qub.ac.u [DAMTP, David Bates Building, Queen' s University Belfast, Belfast, BT7 1NN (United Kingdom)

2009-11-01

New x-ray free electron lasers (FELs) promise an ultra-fast ultra-intense regime in which new physical phenomena, such as double core hole formation in at atom, should become directly observable. Ahead of x-ray FEL experiments, an initial key task is to theoretically explore such fundamental laser-atom interactions and processes. To study the response of a two-electron positive ion to an intense x-ray FEL pulse, our theoretical approach is a direct numerical integration, incorporating non-dipole Hamiltonian terms, of the full six-dimensional time-dependent Schroedinger equation. We present probabilities of double K-shell ionization in the two-electron positive ions Ne{sup 8+} and Ar{sup 16+} exposed to x-ray FEL pulses with frequencies in the range 50 au to 300 au and intensities in the range 10{sup 17} to 10{sup 22} W/cm{sup 2}.

Electron acoustic-Langmuir solitons in a two-component electron plasma

Science.gov (United States)

McKenzie, J. F.

2003-04-01

We investigate the conditions under which ‘high-frequency’ electron acoustic Langmuir solitons can be constructed in a plasma consisting of protons and two electron populations: one ‘cold’ and the other ‘hot’. Conservation of total momentum can be cast as a structure equation either for the ‘cold’ or ‘hot’ electron flow speed in a stationary wave using the Bernoulli energy equations for each species. The linearized version of the governing equations gives the dispersion equation for the stationary waves of the system, from which follows the necessary but not sufficient conditions for the existence of soliton structures; namely that the wave speed must be less than the acoustic speed of the ‘hot’ electron component and greater than the low-frequency compound acoustic speed of the two electron populations. In this wave speed regime linear waves are ‘evanescent’, giving rise to the exponential growth or decay, which readily can give rise to non-linear effects that may balance dispersion and allow soliton formation. In general the ‘hot’ component must be more abundant than the ‘cold’ one and the wave is characterized by a compression of the ‘cold’ component and an expansion in the ‘hot’ component necessitating a potential dip. Both components are driven towards their sonic points; the ‘cold’ from above and the ‘hot’ from below. It is this transonic feature which limits the amplitude of the soliton. If the ‘hot’ component is not sufficiently abundant the window for soliton formation shrinks to a narrow speed regime which is quasi-transonic relative to the ‘hot’ electron acoustic speed, and it is shown that smooth solitons cannot be constructed. In the special case of a very cold electron population (i.e. ‘highly supersonic’) and the other population being very hot (i.e. ‘highly subsonic’) with adiabatic index 2, the structure equation simplifies and can be integrated in terms of elementary

Simulated two-dimensional electronic spectroscopy of the eight-bacteriochlorophyll FMO complex

Energy Technology Data Exchange (ETDEWEB)

Yeh, Shu-Hao [Department of Chemistry and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); Kais, Sabre, E-mail: kais@purdue.edu [Department of Chemistry and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); Qatar Environment and Energy Research Institute, Qatar Foundation, Doha (Qatar)

2014-12-21

The Fenna-Matthews-Olson (FMO) protein-pigment complex acts as a molecular wire conducting energy between the outer antenna system and the reaction center; it is an important photosynthetic system to study the transfer of excitonic energy. Recent crystallographic studies report the existence of an additional (eighth) bacteriochlorophyll a (BChl a) in some of the FMO monomers. To understand the functionality of this eighth BChl, we simulated the two-dimensional electronic spectra of both the 7-site (apo form) and the 8-site (holo form) variant of the FMO complex from green sulfur bacteria, Prosthecochloris aestuarii. By comparing the spectrum, it was found that the eighth BChl can affect two different excitonic energy transfer pathways: (1) it is directly involved in the first apo form pathway (6 → 3 → 1) by passing the excitonic energy to exciton 6; and (2) it facilitates an increase in the excitonic wave function overlap between excitons 4 and 5 in the second pathway (7 → 4,5 → 2 → 1) and thus increases the possible downward sampling routes across the BChls.

Exact exchange-correlation potentials of singlet two-electron systems

Science.gov (United States)

Ryabinkin, Ilya G.; Ospadov, Egor; Staroverov, Viktor N.

2017-10-01

We suggest a non-iterative analytic method for constructing the exchange-correlation potential, v XC ( r ) , of any singlet ground-state two-electron system. The method is based on a convenient formula for v XC ( r ) in terms of quantities determined only by the system's electronic wave function, exact or approximate, and is essentially different from the Kohn-Sham inversion technique. When applied to Gaussian-basis-set wave functions, the method yields finite-basis-set approximations to the corresponding basis-set-limit v XC ( r ) , whereas the Kohn-Sham inversion produces physically inappropriate (oscillatory and divergent) potentials. The effectiveness of the procedure is demonstrated by computing accurate exchange-correlation potentials of several two-electron systems (helium isoelectronic series, H2, H3 + ) using common ab initio methods and Gaussian basis sets.

Electrons in a two-dimensions world

International Nuclear Information System (INIS)

Kivelson, S.; Lee, D.H.; Zhang, S.C.

1996-01-01

This digest paper is a presentation of the recent discoveries about the quantum Hall effect and its links with superconductivity. This effect can occur when electrons are confined inside a thin film between two semiconductor crystals and when they are cooled to a temperature close to 0 deg. K and submitted to an intense magnetic field. Electrons can propagate along the thin film plane when the magnetic field is perpendicular to this plane. When the magnetic field strength increases, a difference of potential occurs (the Hall voltage) and increases by steps inside the thin film and perpendicularly to the current. Each step is characterized by a perfect conductivity of the electrons and by a particular value of the Hall conductance. These steps correspond to fractional multiples of the quantum conductance. The paper describes first the historical aspects that led to the discovery of the quantum Hall effect. Then, this effect is explained using a model in which electrons are assimilated to composed bosons carrying a odd number of magnetic field quanta. This model is used to describe the similarities between the quantum Hall effect and the superconductivity and to draw a phase diagram of the different behaviours of electrons in a plan according to the strength of the magnetic field and to the degree of disorder inside the semiconductor crystals. This diagram show some unexpected properties of electrons which can act like a dielectric material or like a metal. (J.S.). 4 refs., 6 figs., 1 tab

Two-dimensional vibrational-electronic spectroscopy

Science.gov (United States)

Courtney, Trevor L.; Fox, Zachary W.; Slenkamp, Karla M.; Khalil, Munira

2015-10-01

Two-dimensional vibrational-electronic (2D VE) spectroscopy is a femtosecond Fourier transform (FT) third-order nonlinear technique that creates a link between existing 2D FT spectroscopies in the vibrational and electronic regions of the spectrum. 2D VE spectroscopy enables a direct measurement of infrared (IR) and electronic dipole moment cross terms by utilizing mid-IR pump and optical probe fields that are resonant with vibrational and electronic transitions, respectively, in a sample of interest. We detail this newly developed 2D VE spectroscopy experiment and outline the information contained in a 2D VE spectrum. We then use this technique and its single-pump counterpart (1D VE) to probe the vibrational-electronic couplings between high frequency cyanide stretching vibrations (νCN) and either a ligand-to-metal charge transfer transition ([FeIII(CN)6]3- dissolved in formamide) or a metal-to-metal charge transfer (MMCT) transition ([(CN)5FeIICNRuIII(NH3)5]- dissolved in formamide). The 2D VE spectra of both molecules reveal peaks resulting from coupled high- and low-frequency vibrational modes to the charge transfer transition. The time-evolving amplitudes and positions of the peaks in the 2D VE spectra report on coherent and incoherent vibrational energy transfer dynamics among the coupled vibrational modes and the charge transfer transition. The selectivity of 2D VE spectroscopy to vibronic processes is evidenced from the selective coupling of specific νCN modes to the MMCT transition in the mixed valence complex. The lineshapes in 2D VE spectra report on the correlation of the frequency fluctuations between the coupled vibrational and electronic frequencies in the mixed valence complex which has a time scale of 1 ps. The details and results of this study confirm the versatility of 2D VE spectroscopy and its applicability to probe how vibrations modulate charge and energy transfer in a wide range of complex molecular, material, and biological systems.

Two-dimensional vibrational-electronic spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Courtney, Trevor L.; Fox, Zachary W.; Slenkamp, Karla M.; Khalil, Munira, E-mail: mkhalil@uw.edu [Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195 (United States)

2015-10-21

Two-dimensional vibrational-electronic (2D VE) spectroscopy is a femtosecond Fourier transform (FT) third-order nonlinear technique that creates a link between existing 2D FT spectroscopies in the vibrational and electronic regions of the spectrum. 2D VE spectroscopy enables a direct measurement of infrared (IR) and electronic dipole moment cross terms by utilizing mid-IR pump and optical probe fields that are resonant with vibrational and electronic transitions, respectively, in a sample of interest. We detail this newly developed 2D VE spectroscopy experiment and outline the information contained in a 2D VE spectrum. We then use this technique and its single-pump counterpart (1D VE) to probe the vibrational-electronic couplings between high frequency cyanide stretching vibrations (ν{sub CN}) and either a ligand-to-metal charge transfer transition ([Fe{sup III}(CN){sub 6}]{sup 3−} dissolved in formamide) or a metal-to-metal charge transfer (MMCT) transition ([(CN){sub 5}Fe{sup II}CNRu{sup III}(NH{sub 3}){sub 5}]{sup −} dissolved in formamide). The 2D VE spectra of both molecules reveal peaks resulting from coupled high- and low-frequency vibrational modes to the charge transfer transition. The time-evolving amplitudes and positions of the peaks in the 2D VE spectra report on coherent and incoherent vibrational energy transfer dynamics among the coupled vibrational modes and the charge transfer transition. The selectivity of 2D VE spectroscopy to vibronic processes is evidenced from the selective coupling of specific ν{sub CN} modes to the MMCT transition in the mixed valence complex. The lineshapes in 2D VE spectra report on the correlation of the frequency fluctuations between the coupled vibrational and electronic frequencies in the mixed valence complex which has a time scale of 1 ps. The details and results of this study confirm the versatility of 2D VE spectroscopy and its applicability to probe how vibrations modulate charge and energy transfer in a

Classification of Two Class Motor Imagery Tasks Using Hybrid GA-PSO Based K-Means Clustering.

Science.gov (United States)

Suraj; Tiwari, Purnendu; Ghosh, Subhojit; Sinha, Rakesh Kumar

2015-01-01

Transferring the brain computer interface (BCI) from laboratory condition to meet the real world application needs BCI to be applied asynchronously without any time constraint. High level of dynamism in the electroencephalogram (EEG) signal reasons us to look toward evolutionary algorithm (EA). Motivated by these two facts, in this work a hybrid GA-PSO based K-means clustering technique has been used to distinguish two class motor imagery (MI) tasks. The proposed hybrid GA-PSO based K-means clustering is found to outperform genetic algorithm (GA) and particle swarm optimization (PSO) based K-means clustering techniques in terms of both accuracy and execution time. The lesser execution time of hybrid GA-PSO technique makes it suitable for real time BCI application. Time frequency representation (TFR) techniques have been used to extract the feature of the signal under investigation. TFRs based features are extracted and relying on the concept of event related synchronization (ERD) and desynchronization (ERD) feature vector is formed.

Nonequilibrium Transport and the Bernoulli Effect of Electrons in a Two-Dimensional Electron Gas

Science.gov (United States)

Kaya, Ismet I.

2013-02-01

Nonequilibrium transport of charged carriers in a two-dimensional electron gas is summarized from an experimental point of view. The transport regime in which the electron-electron interactions are enhanced at high bias leads to a range of striking effects in a two-dimensional electron gas. This regime of transport is quite different than the ballistic transport in which particles propagate coherently with no intercarrier energy transfer and the diffusive transport in which the momentum of the electron system is lost with the involvement of the phonons. Quite a few hydrodynamic phenomena observed in classical gasses have the electrical analogs in the current flow. When intercarrier scattering events dominate the transport, the momentum sharing via narrow angle scattering among the hot and cold electrons lead to negative resistance and electron pumping which can be viewed as the analog of the Bernoulli-Venturi effect observed classical gasses. The recent experimental findings and the background work in the field are reviewed.

Magnetooscillations of the tunneling current between two-dimensional electron systems

International Nuclear Information System (INIS)

Raichev, O.E.; Vasko, F.T.

1995-08-01

We calculate electric current caused by electron tunnelling between two-dimensional layers in the magnetic field applied perpendicular to the layers. An elastic scattering of the electrons is taken into account. Analytical results are obtained for two regimes: i) small magnetic field, when the Landau quantization is suppressed by the scattering and the oscillatory part of the current shows nearly harmonic behaviour; ii) high magnetic field, when the Landau levels are well-defined and the conductivity shows series of sharp peaks corresponding to resonant magnetotunneling. In the last case, we used two alternative approaches: self-consistent Born approximation and path integral method, and compared obtained results. (author). 12 refs, 3 figs

New method of ionization energy calculation for two-electron ions

International Nuclear Information System (INIS)

Ershov, D.K.

1997-01-01

A new method for calculation of the ionization energy of two-electron ions is proposed. The method is based on the calculation of the energy of second electron interaction with the field of an one-electron ion the potential of which is well known

Dynamic performance analysis of two regional Nuclear Hybrid Energy Systems

International Nuclear Information System (INIS)

Garcia, Humberto E.; Chen, Jun; Kim, Jong S.; Vilim, Richard B.; Binder, William R.; Bragg Sitton, Shannon M.; Boardman, Richard D.; McKellar, Michael G.; Paredis, Christiaan J.J.

2016-01-01

In support of more efficient utilization of clean energy generation sources, including renewable and nuclear options, HES (hybrid energy systems) can be designed and operated as FER (flexible energy resources) to meet both electrical and thermal energy needs in the electric grid and industrial sectors. These conceptual systems could effectively and economically be utilized, for example, to manage the increasing levels of dynamic variability and uncertainty introduced by VER (variable energy resources) such as renewable sources (e.g., wind, solar), distributed energy resources, demand response schemes, and modern energy demands (e.g., electric vehicles) with their ever changing usage patterns. HES typically integrate multiple energy inputs (e.g., nuclear and renewable generation) and multiple energy outputs (e.g., electricity, gasoline, fresh water) using complementary energy conversion processes. This paper reports a dynamic analysis of two realistic HES including a nuclear reactor as the main baseload heat generator and to assess the local (e.g., HES owners) and system (e.g., the electric grid) benefits attainable by their application in scenarios with multiple commodity production and high renewable penetration. It is performed for regional cases – not generic examples – based on available resources, existing infrastructure, and markets within the selected regions. This study also briefly addresses the computational capabilities developed to conduct such analyses. - Highlights: • Hybrids including renewables can operate as dispatchable flexible energy resources. • Nuclear energy can address high variability and uncertainty in energy systems. • Nuclear hybrids can reliably provide grid services over various time horizons. • Nuclear energy can provide operating reserves and grid inertia under high renewables. • Nuclear hybrids can greatly reduce GHG emissions and support grid and industry needs.

Zero-point energies in the two-center shell model

International Nuclear Information System (INIS)

Reinhard, P.G.

1975-01-01

The zero-point energies (ZPE) contained in the potential-energy surfaces (PES) of a two-center shell model are evaluated. For the c.m. motion of the system as a whole the kinetic ZPE was found to be negligible, whereas it varies appreciably for the rotational and oscillation modes (about 5-9MeV). For the latter two modes the ZPE also depends sensitively on the changing pairing structure, which can induce strong local fluctuations, particularly in light nuclei. The potential ZPE is very small for heavy nuclei, but might just become important in light nuclei. (Auth.)

Hybrid integrated sensor for position measurement

International Nuclear Information System (INIS)

Schmidt, B.; Schott, H.; Just, H.-J.

1986-01-01

The design, fabrication and performance of an integrated two-dimensional position sensitive photodetector are presented. The optoelectronic device used as sensitive element in the circuit is a full area position sensitive photodiode (PPD) with high linearity over the full sensitive area. The PPD is integrated with the analog electronics in a hybrid circuit using thick film technology. The analog electronics includes the signal amplification and the signal conditioning to form the output signals proportional to the light beam center position at the sensor surface and an output signal proportional to the light beam intensity. Using hybrid integration a new position sensitive transducer is developed giving output signals, transmiting in large distances without problems and driving directly actuators in any control system

Identification of two proteins that interact with the Erp virulence factor from Mycobacterium tuberculosis by using the bacterial two-hybrid system

Directory of Open Access Journals (Sweden)

Cataldi Angel A

2009-01-01

Full Text Available Abstract Background The exported repetitive protein (erp gene encodes a secreted 36-kDa protein with a central domain containing several proline-glycine-leucine-threonine-serine (PGLTS repeats. It has been demonstrated that erp is a virulence-associated factor since the disruption of this gene impairs the growth of Mycobacterium bovis and Mycobacterium tuberculosis in mice. Results In order to elucidate the function of Erp we searched for Erp-binding proteins from M. tuberculosis by using a bacterial two-hybrid system. Our results indicate that Erp interacts specifically with two putative membrane proteins, Rv1417 and Rv2617c. Further analysis revealed that the latter two interact with each other, indicating that Rv1417, Rv2617c and Erp are connected through multiple interactions. While Rv1417 is disseminated in several Actinomycetales genera, orthologues of Rv2617c are exclusively present in members of the M. tuberculosis complex (MTC. The central and amino-terminal regions of Erp were determined to be involved in the interaction with Rv1417 and Rv2627c. Erp forms from Mycobacterium smegmatis and Mycobacterium leprae were not able to interact with Rv2617c in two-hybrid assays. Immunolocalization experiments showed that Rv1417 and Rv2617c are found on the cell membrane and Erp on the bacterial cell wall. Finally, comparative genomics and expression studies revealed a possible role of Rv1417 in riboflavin metabolism. Conclusion We identified interactive partners of Erp, an M. tuberculosis protein involved in virulence, which will be the focus of future investigation to decipher the function of the Erp family protein.

Nonvolatile two-step, two-color holography with continuous-wave lights for both congruent and near-stoichiometric LiNbO3:Fe

International Nuclear Information System (INIS)

Shen Yan; Zhang Guoquan; Fu Bo; Xu Qingjun; Xu Jingjun

2004-01-01

We have studied theoretically the steady-state nonvolatile two-step, two-color holographic recording performance for both the congruent and the near-stoichiometric LiNbO 3 :Fe based on the two-center model (the deep-trap and the shallow-trap centers are Fe 2+ /Fe 3+ and Nb Li 4+ /Nb Li 5+ , respectively). The results show that the direct electron exchange between the Fe 2+ /Fe 3+ centers and the Nb Li 4+ /Nb Li 5+ centers due to the tunneling effect dominates the charge-transfer process during the nonvolatile two-step, two-color holography and determines the two-step, two-color holography performance in LiNbO 3 :Fe. We have further studied the effects of the crystal stoichiometry on the performance of the two-step, two-color holography. It is shown that, as far as the total space-charge field is considered, the nonvolatile two-step, two-color holography performance in the near-stoichiometric LiNbO 3 :Fe is much better than that in the congruent LiNbO 3 :Fe within the intensity range reachable by the continuous-wave lights

Randomized controlled split-mouth clinical trial of direct laminate veneers with two micro-hybrid resin composites

NARCIS (Netherlands)

Gresnigt, Marco M. M.; Kalk, Warner; Ozcan, M.; Ozcan, Mutlu

Objectives: This randomized, split-mouth clinical study evaluated the survival rate of direct laminate veneers made of two resin-composite materials. Methods: A total of 23 patients (mean age: 52.4 years old) received 96 direct composite laminate veneers using two micro-hybrid composites in

Alternative Fuels Data Center: Hybrid and Plug-In Electric Vehicle

Science.gov (United States)

Conversions Hybrid and Plug-In Electric Vehicle Conversions to someone by E-mail Share Alternative Fuels Data Center: Hybrid and Plug-In Electric Vehicle Conversions on Facebook Tweet about Alternative Fuels Data Center: Hybrid and Plug-In Electric Vehicle Conversions on Twitter Bookmark Alternative

Electron-electron interaction in strong electromagnetic fields The two-electron contribution to the ground-state energy in He-like uranium

CERN Document Server

Gumberidze, A; Barnás, D; Beckert, Karl; Beller, Peter; Beyer, H F; Bosch, F; Cai, X; Stöhlker, T; Hagmann, S; Kozhuharov, C; Liesen, D; Nolden, F; Ma, X; Mokler, P H; Orsic-Muthig, A; Steck, Markus; Sierpowski, D; Tashenov, S; Warczak, A; Zou, Y

2004-01-01

Radiative recombination transitions into the ground state of cooled bare and hydrogen-like uranium ions were measured at the storage ring ESR. By comparing the corresponding x-ray centroid energies, this technique allows for a direct measurement of the electron-electron contribution to the ionization potential in the heaviest He-like ions. For the two-electron contribution to the ionization potential of He-like uranium we obtain a value of 2248 ± 9 eV. This represents the most accurate determination of two-electron effects in the domain of high-Z He-like ions and the accuracy reaches already the size of the specific two-electron radiative QED corrections.

Photoelectron spectra as a probe of double-core resonsance in two-electron atoms

International Nuclear Information System (INIS)

Grobe, R.; Haan, S.L.; Eberly, J.H.

1996-01-01

The authors calculate photoelectron spectra for a two-electron atom under the influence of two external driving fields, using an essential states formalism. They focus on the regime of so-called coherence transfer, in which electron-electron correlation transfers field-induced photo-coherence from one electron to the other. In the case studied here, two laser fields are resonant with coupled atomic transitions, in the manner familiar from three-level dark-state spectroscopy. Dynamical two electron effects are monitored via the photoelectron energy spectrum. The authors show that the distribution of the photoelectron energies can be singly, doubly or triply peaked depending on the relative laser intensities. The electron spectra are independent of the turn-on sequence of the fields

Quantum ballistic transport by interacting two-electron states in quasi-one-dimensional channels

Energy Technology Data Exchange (ETDEWEB)

Huang, Danhong [Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, New Mexico 87117 (United States); Center for High Technology Materials, University of New Mexico, 1313 Goddard St SE, Albuquerque, New Mexico 87106 (United States); Gumbs, Godfrey [Center for High Technology Materials, University of New Mexico, 1313 Goddard St SE, Albuquerque, New Mexico 87106 (United States); Abranyos, Yonatan [Department of Physics and Astronomy, Hunter College of the City University of New York, 695 Park Avenue, New York, New York 10065 (United States); Pepper, Michael; Kumar, Sanjeev [Department of Electronic and Electrical Engineering, University College London, London, WC1E 7JE (United Kingdom); London Centre for Nanotechnology, 17-19 Gordon Street, London, WC1H 0AH (United Kingdom)

2015-11-15

For quantum ballistic transport of electrons through a short conduction channel, the role of Coulomb interaction may significantly modify the energy levels of two-electron states at low temperatures as the channel becomes wide. In this regime, the Coulomb effect on the two-electron states is calculated and found to lead to four split energy levels, including two anticrossing-level and two crossing-level states. Moreover, due to the interplay of anticrossing and crossing effects, our calculations reveal that the ground two-electron state will switch from one anticrossing state (strong confinement) to a crossing state (intermediate confinement) as the channel width gradually increases and then back to the original anticrossing state (weak confinement) as the channel width becomes larger than a threshold value. This switching behavior leaves a footprint in the ballistic conductance as well as in the diffusion thermoelectric power of electrons. Such a switching is related to the triple spin degeneracy as well as to the Coulomb repulsion in the central region of the channel, which separates two electrons away and pushes them to different channel edges. The conductance reoccurrence region expands from the weak to the intermediate confinement regime with increasing electron density.

In situ hybridization at the electron microscope level: hybrid detection by autoradiography and colloidal gold.

Science.gov (United States)

Hutchison, N J; Langer-Safer, P R; Ward, D C; Hamkalo, B A

1982-11-01

In situ hybridization has become a standard method for localizing DNA or RNA sequences in cytological preparations. We developed two methods to extend this technique to the transmission electron microscope level using mouse satellite DNA hybridization to whole mount metaphase chromosomes as the test system. The first method devised is a direct extension of standard light microscope level using mouse satellite DNA hybridization to whole mount metaphase chromosomes as the test system. The first method devised is a direct extension of standard light microscope in situ hybridization. Radioactively labeled complementary RNA (cRNA) is hybridized to metaphase chromosomes deposited on electron microscope grids and fixed in 70 percent ethanol vapor; hybridixation site are detected by autoradiography. Specific and intense labeling of chromosomal centromeric regions is observed even after relatively short exposure times. Inerphase nuclei present in some of the metaphase chromosome preparations also show defined paatterms of satellite DNA labeling which suggests that satellite-containing regions are associate with each other during interphase. The sensitivity of this method is estimated to at least as good as that at the light microscope level while the resolution is improved at least threefold. The second method, which circumvents the use of autoradiogrphic detection, uses biotin-labeled polynucleotide probes. After hybridization of these probes, either DNA or RNA, to fixed chromosomes on grids, hybrids are detected via reaction is improved at least threefold. The second method, which circumvents the use of autoradiographic detection, uses biotin-labeled polynucleotide probes. After hybridization of these probes, either DNA or RNA, to fixed chromosomes on grids, hybrids are detected via reaction with an antibody against biotin and secondary antibody adsorbed to the surface of over centromeric heterochromatin and along the associated peripheral fibers. Labeling is on average

Criteria governing electron plasma waves in a two-temperature plasma

International Nuclear Information System (INIS)

Dell, M.P.; Gledhill, I.M.A.; Hellberg, M.A.

1987-01-01

Using a technique based on the saddle-points of the dielectric function, criteria are found which govern the behaviour of electron plasma waves in plasmas with two electron populations having different temperatures. (orig.)

Model of two-dimensional electron gas formation at ferroelectric interfaces

Energy Technology Data Exchange (ETDEWEB)

Aguado-Puente, P.; Bristowe, N. C.; Yin, B.; Shirasawa, R.; Ghosez, Philippe; Littlewood, P. B.; Artacho, Emilio

2015-07-01

The formation of a two-dimensional electron gas at oxide interfaces as a consequence of polar discontinuities has generated an enormous amount of activity due to the variety of interesting effects it gives rise to. Here, we study under what circumstances similar processes can also take place underneath ferroelectric thin films. We use a simple Landau model to demonstrate that in the absence of extrinsic screening mechanisms, a monodomain phase can be stabilized in ferroelectric films by means of an electronic reconstruction. Unlike in the LaAlO3/SrTiO3 heterostructure, the emergence with thickness of the free charge at the interface is discontinuous. This prediction is confirmed by performing first-principles simulations of free-standing slabs of PbTiO3. The model is also used to predict the response of the system to an applied electric field, demonstrating that the two-dimensional electron gas can be switched on and off discontinuously and in a nonvolatile fashion. Furthermore, the reversal of the polarization can be used to switch between a two-dimensional electron gas and a two-dimensional hole gas, which should, in principle, have very different transport properties. We discuss the possible formation of polarization domains and how such configuration competes with the spontaneous accumulation of free charge at the interfaces.

Inter-layer Cooper pairing of two-dimensional electrons

International Nuclear Information System (INIS)

Inoue, Masahiro; Takemori, Tadashi; Yoshizaki, Ryozo; Sakudo, Tunetaro; Ohtaka, Kazuo

1987-01-01

The authors point out the possibility that the high transition temperatures of the recently discovered oxide superconductors are dominantly caused by the inter-layer Cooper pairing of two-dimensional electrons that are coupled through the exchange of three-dimensional phonons. (author)

Large non-Gaussianity from two-component hybrid inflation

International Nuclear Information System (INIS)

Byrnes, Christian T.; Choi, Ki-Young; Hall, Lisa M.H.

2009-01-01

We study the generation of non-Gaussianity in models of hybrid inflation with two inflaton fields, (2-brid inflation). We analyse the region in the parameter and the initial condition space where a large non-Gaussianity may be generated during slow-roll inflation which is generally characterised by a large f NL , τ NL and a small g NL . For certain parameter values we can satisfy τ NL >> f NL 2 . The bispectrum is of the local type but may have a significant scale dependence. We show that the loop corrections to the power spectrum and bispectrum are suppressed during inflation, if one assume that the fields follow a classical background trajectory. We also include the effect of the waterfall field, which can lead to a significant change in the observables after the waterfall field is destabilised, depending on the couplings between the waterfall and inflaton fields

Color center annealing and ageing in electron and ion-irradiated yttria-stabilized zirconia

International Nuclear Information System (INIS)

Costantini, Jean-Marc; Beuneu, Francois

2005-01-01

We have used X-band electron paramagnetic resonance (EPR) measurements at room-temperature (RT) to study the thermal annealing and RT ageing of color centers induced in yttria-stabilized zirconia (YSZ), i.e. ZrO 2 :Y with 9.5 mol% Y 2 O 3 , by swift electron and ion-irradiations. YSZ single crystals with the orientation were irradiated with 2.5 MeV electrons, and implanted with 100 MeV 13 C ions. Electron and ion beams produce the same two color centers, namely an F + -type center (singly ionized oxygen vacancy) and the so-called T-center (Zr 3+ in a trigonal oxygen local environment) which is also produced by X-ray irradiations. Isochronal annealing was performed in air up to 973 K. For both electron and ion irradiations, the defect densities are plotted versus temperature or time at various fluences. The influence of a thermal treatment at 1373 K of the YSZ single crystals under vacuum prior to the irradiations was also investigated. In these reduced samples, color centers are found to be more stable than in as-received samples. Two kinds of recovery processes are observed depending on fluence and heat treatment

Stability and carrier mobility of organic-inorganic hybrid perovskite CH3NH3PbI3 in two-dimensional limit

Science.gov (United States)

Huang, Kui; Lai, Kang; Yan, Chang-Lin; Zhang, Wei-Bing

2017-10-01

Recently, atomically thin organic-inorganic hybrid perovskites have been synthesized experimentally, which opens up new opportunities for exploring their novel properties in the 2D limit. Based on the comparative density functional theory calculation with and without spin-orbit coupling effects, the stability, electronic structure, and carrier mobility of the two-dimensional organic-inorganic hybrid perovskites MAPbI3 (MA = CH3NH3) have been investigated systemically. Two single-unit-cell-thick 2D MAPbI3 terminated by PbI2 and CH3NH3I are constructed, and their thermodynamic stabilities are also evaluated using the first-principles constrained thermodynamics method. Our results indicate that both 2D MAPbI3 with different terminations can be stable under certain conditions and have a suitable direct bandgap. Moreover, they are also found to have termination-dependent band edge and carrier mobility. The acoustic-phonon-limited carrier mobilities estimated using the deformation theory and effective mass approximation are on the order of thousands of square centimeters per volt per second and also highly anisotropic. These results indicate that 2D MAPbI3 are competitive candidates for low-dimensional photovoltaic applications.

Comparative analysis of electron-density and electron-localization function for dinuclear manganese complexes with bridging boron- and carbon-centered ligands.

Science.gov (United States)

Götz, Kathrin; Kaupp, Martin; Braunschweig, Holger; Stalke, Dietmar

2009-01-01

Bonding in borylene-, carbene-, and vinylidene-bridged dinuclear manganese complexes [MnCp(CO)(2)](2)X (X = B-tBu, B = NMe(2), CH(2), C=CH(2)) has been compared by analyses based on quantum theory of atoms in molecules (QTAIM), on the electron-localization function (ELF), and by natural-population analyses. All of the density functional theory based analyses agree on the absence of a significant direct Mn-Mn bond in these complexes and confirm a dominance of delocalized bonding via the bridging ligand. Interestingly, however, the topology of both charge density and ELF related to the Mn-bridge-Mn bonding depend qualitatively on the chosen density functional (except for the methylene-bridged complex, which exhibits only one three-center-bonding attractor both in -nabla(2)rho and in ELF). While gradient-corrected functionals provide a picture with localized two-center X-Mn bonding, increasing exact-exchange admixture in hybrid functionals concentrates charge below the bridging atom and suggests a three-center bonding situation. For example, the bridging boron ligands may be described either as substituted boranes (e.g., at BLYP or BP86 levels) or as true bridging borylenes (e.g., at BHLYP level). This dependence on the theoretical level appears to derive from a bifurcation between two different bonding situations and is discussed in terms of charge transfer between X and Mn, and in the context of self-interaction errors exhibited by popular functionals.

Electron correlation energy in confined two-electron systems

Energy Technology Data Exchange (ETDEWEB)

Wilson, C.L. [Chemistry Program, Centre College, 600 West Walnut Street, Danville, KY 40422 (United States); Montgomery, H.E., E-mail: ed.montgomery@centre.ed [Chemistry Program, Centre College, 600 West Walnut Street, Danville, KY 40422 (United States); Sen, K.D. [School of Chemistry, University of Hyderabad, Hyderabad 500 046 (India); Thompson, D.C. [Chemistry Systems and High Performance Computing, Boehringer Ingelheim Pharamaceuticals Inc., 900 Ridgebury Road, Ridgefield, CT 06877 (United States)

2010-09-27

Radial, angular and total correlation energies are calculated for four two-electron systems with atomic numbers Z=0-3 confined within an impenetrable sphere of radius R. We report accurate results for the non-relativistic, restricted Hartree-Fock and radial limit energies over a range of confinement radii from 0.05-10a{sub 0}. At small R, the correlation energies approach limiting values that are independent of Z while at intermediate R, systems with Z{>=}1 exhibit a characteristic maximum in the correlation energy resulting from an increase in the angular correlation energy which is offset by a decrease in the radial correlation energy.

Generation of runaway electrons during deterioration of lower hybrid power coupling in lower hybrid current drive plasmas in the HT-7 tokamak

International Nuclear Information System (INIS)

Chen, Z Y; Ju, H J; Zhu, J X; Li, M; Cai, W D; Liang, H F; Wan, B N; Shi, Y J; Xu, H D

2009-01-01

Efficient coupling of lower hybrid (LH) power from the wave launcher to the plasma is a very important issue in lower hybrid current drive (LHCD) experiments. The large unbalanced reflections in the grill trigger the LH protection system, which will trip the power, resulting in the reduction of the coupled LH power. The generation of runaway electrons has been investigated in LHCD plasmas with deterioration of LH coupling in the HT-7 tokamak. The deterioration of LH coupling results in an increase of the loop voltage and a more energetic fast electron population. These two effects favor the generation of a runaway population. It is found that most of the fast electrons generated by LH waves through parallel electron Landau damping were converted into a runaway population through the acceleration from the toroidal electric field when significant deterioration of LH coupling occurs.

Electronic properties in a two-dimensional disordered electron liquid: Spin-valley interplay

International Nuclear Information System (INIS)

Burmistrov, I. S.; Chtchelkatchev, N. M.

2008-01-01

We report a detailed study of the influence of the spin and valley splittings on such physical observables of the two-dimensional disordered electron liquid as resistivity and spin and valley susceptibilities. We explain qualitatively the nonmonotonic dependence of the resistivity on temperature in the presence of a parallel magnetic field. In the presence of either spin or valley splitting we predict a temperature dependence of the resistivity with two maximum points

Space-group approach to two-electron states in unconventional superconductors

International Nuclear Information System (INIS)

Yarzhemsky, V. G.

2008-01-01

The direct application of the space-group representation theory, makes possible to obtain limitations for the symmetry of SOP on lines and planes of symmetry in one-electron Brillouin zone. In the case of highly symmetric UPt 3 only theoretical nodal structure of IR E 2u is in agreement with all the experimental results. On the other hand, in the case of high-T c superconductors the two electron description of Cooper pairs in D 2h symmetry is not sufficient to describe experimental nodal structure. It was shown that in this case, the nodal structure is the result of underlying interactions between two-electron states and hidden symmetry D-4 h . (author)

Two-Channel Kondo Effect in a Modified Single Electron Transistor

Science.gov (United States)

Oreg, Yuval; Goldhaber-Gordon, David

2003-04-01

We suggest a simple system of two electron droplets which should display two-channel Kondo behavior at experimentally accessible temperatures. Stabilization of the two-channel Kondo fixed point requires fine control of the electrochemical potential in each droplet, which can be achieved by adjusting voltages on nearby gate electrodes. We study the conditions for obtaining this type of two-channel Kondo behavior, discuss the experimentally observable consequences, and explore the gener­alization to the multichannel Kondo case.

Influence of 24-epibrassinolide on seedling growth and distribution of mineral elements in two maize hybrids

Directory of Open Access Journals (Sweden)

Waisi Hadi K.

2017-01-01

Full Text Available In this study, influence of wide range of 24-epibrassinolide (24-EBL on early growth potential of two maize hybrids (ZP 434 and ZP 704 was examined. Paper concerns germination, seedling biomass, important chlorophylls content, and redistribution of elements (heavy metals and microelements, in a seedlings of the maize hybrids, as influenced by different 24-EBL concentrations. It was found that hybrids react differently to exogenously applied hormone. The biggest differences between two examined maize hybrids considering the germination level were reached with the lowest values at 86% for ZP 704 and 72% for ZP 434, gained at the highest applied concentration of 24-EBL. Seedlings of hybrid ZP 434 reacted positively moderately in the case of shoot length and biomass under the influence of 24-EBL, but seedlings of hybrid ZP 704 had lower values of these parameters under the influence of the phytohormone. Chlorophyll a/b ratios showed that photosynthetic apparatus of seedlings of the hybrids is not active in this stage of development. It was established that 24-EBL affects seedling growth and re-allocation of naturally present mineral elements in early growth stages and that could be one of the reason for poorer growth of ZP 704 treated with various concentrations of 24-EBL, comparing to control. When applied in lower concentrations, 24-EBL is blocking toxic elements such as chromium and nickel to relocate to vital parts of plant, what was case in hybrid ZP704. In case of ZP 434, lower concentrations of 24-EBL are affecting re-allocation of Cu and Cr and these findings suggest that maize hybrid seedlings treated with lower concentrations of 24-EBL could survive and be successful in polluted areas. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR31080

Ion emission from laser-produced plasmas with two electron temperatures

International Nuclear Information System (INIS)

Wickens, L.M.; Allen, J.E.; Rumsby, P.T.

1978-01-01

An analytic theory for the expansion of a laser-produced plasma with two electron temperatures is presented. It is shown that from the ion-emission velocity spectrum such relevant parameters as the hot- to -cold-electron density ratio, the absolute hot- and cold-electron temperatures, and a sensitive measure of hot- and cold-electron temperature ratio can be deduced. A comparison with experimental results is presented

Hybrid two fuel system nozzle with a bypass connecting the two fuel systems

Science.gov (United States)

Varatharajan, Balachandar [Cincinnati, OH; Ziminsky, Willy Steve [Simpsonville, SC; Yilmaz, Ertan [Albany, NY; Lacy, Benjamin [Greer, SC; Zuo, Baifang [Simpsonville, SC; York, William David [Greer, SC

2012-05-29

A hybrid fuel combustion nozzle for use with natural gas, syngas, or other types of fuels. The hybrid fuel combustion nozzle may include a natural gas system with a number of swozzle vanes and a syngas system with a number of co-annular fuel tubes.

PERFORMANCE OF PROMISING HYBRID RICE IN TWO DIFFERENT ELEVATIONS OF IRRIGATED LOWLAND IN INDONESIA

Directory of Open Access Journals (Sweden)

Yuni Widyastuti

2015-06-01

Full Text Available The hybrid rice program has been established since early 1990’s at the Indonesia Center for Rice Research (ICRR. Twenty-four experimental hybrid rice varieties which have been developed were tested in lowland rice fields in Sukamandi (West Java and Batang (Central Java during the dry season and the rainy season of 2012. Randomized complete block design (RCBD with three replications was used in each location. The results showed that grains yields were affected by locations, seasons, and genotypes. The genotypes x locations x seasons interaction effect was significant; therefore, the best hybrid was different for each location and season. A7/PK36 hybrid has the best performance in Batang during the dry season, while A7/PK40 and A7/PK32 are the best hybrids in the rainy season. In Sukamandi, nine hybrids were identified as better yielder than that of the check cultivar in the dry season, but not so in the rainy season. Using the correlation and path analysis, we found that the number of panicles per hill and the number of filled grains per panicle could be used as selection criteria for yield in hybrid rice.

Excitation two-center interference and the orbital geometry in laser-induced nonsequential double ionization of diatomic molecules

International Nuclear Information System (INIS)

Shaaran, T.; Augstein, B. B.; Figueira de Morisson Faria, C.

2011-01-01

We address the influence of the molecular orbital geometry and of the molecular alignment with respect to the laser-field polarization on laser-induced nonsequential double ionization of diatomic molecules for different molecular species, namely N 2 and Li 2 . We focus on the recollision excitation with subsequent tunneling ionization (RESI) mechanism, in which the first electron, upon return, promotes the second electron to an excited state, from where it subsequently tunnels. We assume that both electrons are initially in the highest occupied molecular orbital (HOMO) and that the second electron is excited to the lowest unoccupied molecular orbital (LUMO). We show that the electron-momentum distributions exhibit interference maxima and minima due to the electron emission at spatially separated centers. We provide generalized analytical expressions for such maxima or minima, which take into account s-p mixing and the orbital geometry. The patterns caused by the two-center interference are sharpest for vanishing alignment angle and get washed out as this parameter increases. Apart from that, there exist features due to the geometry of the LUMO, which may be observed for a wide range of alignment angles. Such features manifest themselves as the suppression of probability density in specific momentum regions due to the shape of the LUMO wave function, or as an overall decrease in the RESI yield due to the presence of nodal planes.

Correlation and Entanglement in Elliptically Deformed Two-Electron Quantum Dots

International Nuclear Information System (INIS)

Okopinska, A.; Koscik, P.

2011-01-01

We study quantum correlation in a two-dimensional system of two Coulombically interacting electrons trapped in an anisotropic harmonic potential in dependence on the interaction strength. The linear entropy and von Neumann entropy that measure the entanglement between the electrons are compared with the correlation energy and the statistical correlation coefficient. We observe that the entanglement properties are dramatically influenced by the anisotropy of the confining potential. We observe that the energetic and statistical correlations get stronger, whereas the entropic measures show weakening of the correlations with anisotropy. (author)

Thermoelectric power and topological transitions in quasi-two-dimensional electronic systems

International Nuclear Information System (INIS)

Blanter, Ya.M.; Pantsulaya, A.V.; Varlamov, A.A.

1991-05-01

Electron-impurity relaxation time and the thermoelectric power (TEP) of quasi-two-dimensional electron gas are calculated. Two cases are discussed: the isotropic spectrum and the electronic topological transition (ETT) of the ''neck-breaking'' type. Methods of thermal diagramatic technique are used for the calculation. It is found that the TEP in the vicinity of the ETT greatly exceeds its background value. The results of experimental investigations of the TEP in the metal-oxide-semiconductor structures are compared with the predictions of the proposed theory. (author). 17 refs, 5 figs

Solitary Langmuir waves in two-electron temperature plasma

Science.gov (United States)

Prudkikh, V. V.; Prudkikh

2014-06-01

Nonlinear interaction of Langmuir and ion-acoustic waves in two-electron temperature plasma is investigated. New integrable wave interaction regime was discovered, this regime corresponds to the Langmuir soliton with three-hump amplitude, propagating with a speed close to the ion-sound speed in the conditions of strong non-isothermality of electronic components. It was discovered that besides the known analytical solution in the form of one- and two-hump waves, there exists a range of solutions in the form of solitary waves, which in the form of envelope has multi-peak structure and differs from the standard profiles described by hyperbolic functions. In case of fixed plasma parameters, different group velocities correspond to the waves with different number of peaks. It is found that the Langmuir wave package contains both even and uneven numbers of oscillations. Low-frequency potential here has uneven number of peaks. Interrelation of obtained and known earlier results are also discussed.

Performance analysis of three-dimensional-triple-level cell and two-dimensional-multi-level cell NAND flash hybrid solid-state drives

Science.gov (United States)

Sakaki, Yukiya; Yamada, Tomoaki; Matsui, Chihiro; Yamaga, Yusuke; Takeuchi, Ken

2018-04-01

In order to improve performance of solid-state drives (SSDs), hybrid SSDs have been proposed. Hybrid SSDs consist of more than two types of NAND flash memories or NAND flash memories and storage-class memories (SCMs). However, the cost of hybrid SSDs adopting SCMs is more expensive than that of NAND flash only SSDs because of the high bit cost of SCMs. This paper proposes unique hybrid SSDs with two-dimensional (2D) horizontal multi-level cell (MLC)/three-dimensional (3D) vertical triple-level cell (TLC) NAND flash memories to achieve higher cost-performance. The 2D-MLC/3D-TLC hybrid SSD achieves up to 31% higher performance than the conventional 2D-MLC/2D-TLC hybrid SSD. The factors of different performance between the proposed hybrid SSD and the conventional hybrid SSD are analyzed by changing its block size, read/write/erase latencies, and write unit of 3D-TLC NAND flash memory, by means of a transaction-level modeling simulator.

Bridge mediated two-electron transfer reactions: Analysis of stepwise and concerted pathways

International Nuclear Information System (INIS)

Petrov, E.G.; May, V.

2004-01-01

A theory of nonadiabatic donor (D)-acceptor (A) two-electron transfer (TET) mediated by a single regular bridge (B) is developed. The presence of different intermediate two-electron states connecting the reactant state D -- BA with the product state DBA -- results in complex multiexponential kinetics. The conditions are discussed at which a reduction to two-exponential as well as single-exponential kinetics becomes possible. For the latter case the rate K TET is calculated, which describes the bridge-mediated reaction as an effective two-electron D-A transfer. In the limit of small populations of the intermediate TET states D - B - A, DB -- A, D - BA - , and DB - A - , K TET is obtained as a sum of the rates K TET (step) and K TET (sup) . The first rate describes stepwise TET originated by transitions of a single electron. It starts at D -- BA and reaches DBA -- via the intermediate state D - BA - . These transitions cover contributions from sequential as well as superexchange reactions all including reduced bridge states. In contrast, a specific two-electron superexchange mechanism from D -- BA to DBA -- defines K TET (sup) . An analytic dependence of K TET (step) and K TET (sup) on the number of bridging units is presented and different regimes of D-A TET are studied

Effect of two-temperature electrons distribution on an electrostatic plasma sheath

International Nuclear Information System (INIS)

Ou, Jing; Xiang, Nong; Gan, Chunyun; Yang, Jinhong

2013-01-01

A magnetized collisionless plasma sheath containing two-temperature electrons is studied using a one-dimensional model in which the low-temperature electrons are described by Maxwellian distribution (MD) and high-temperature electrons are described by truncated Maxwellian distribution (TMD). Based on the ion wave approach, a modified sheath criterion including effect of TMD caused by high-temperature electrons energy above the sheath potential energy is established theoretically. The model is also used to investigate numerically the sheath structure and energy flux to the wall for plasmas parameters of an open divertor tokamak-like. Our results show that the profiles of the sheath potential, two-temperature electrons and ions densities, high-temperature electrons and ions velocities as well as the energy flux to the wall depend on the high-temperature electrons concentration, temperature, and velocity distribution function associated with sheath potential. In addition, the results obtained in the high-temperature electrons with TMD as well as with MD sheaths are compared for the different sheath potential

Two-parametric model of electron beam in computational dosimetry for radiation processing

International Nuclear Information System (INIS)

Lazurik, V.M.; Lazurik, V.T.; Popov, G.; Zimek, Z.

2016-01-01

Computer simulation of irradiation process of various materials with electron beam (EB) can be applied to correct and control the performances of radiation processing installations. Electron beam energy measurements methods are described in the international standards. The obtained results of measurements can be extended by implementation computational dosimetry. Authors have developed the computational method for determination of EB energy on the base of two-parametric fitting of semi-empirical model for the depth dose distribution initiated by mono-energetic electron beam. The analysis of number experiments show that described method can effectively consider random displacements arising from the use of aluminum wedge with a continuous strip of dosimetric film and minimize the magnitude uncertainty value of the electron energy evaluation, calculated from the experimental data. Two-parametric fitting method is proposed for determination of the electron beam model parameters. These model parameters are as follow: E 0 – energy mono-energetic and mono-directional electron source, X 0 – the thickness of the aluminum layer, located in front of irradiated object. That allows obtain baseline data related to the characteristic of the electron beam, which can be later on applied for computer modeling of the irradiation process. Model parameters which are defined in the international standards (like E p – the most probably energy and R p – practical range) can be linked with characteristics of two-parametric model (E 0 , X 0 ), which allows to simulate the electron irradiation process. The obtained data from semi-empirical model were checked together with the set of experimental results. The proposed two-parametric model for electron beam energy evaluation and estimation of accuracy for computational dosimetry methods on the base of developed model are discussed. - Highlights: • Experimental and computational methods of electron energy evaluation. • Development

Electron imaging with Medipix2 hybrid pixel detector

CERN Document Server

McMullan, G; Chen, S; Henderson, R; Llopart, X; Summerfield, C; Tlustos, L; Faruqi, A R

2007-01-01

The electron imaging performance of Medipix2 is described. Medipix2 is a hybrid pixel detector composed of two layers. It has a sensor layer and a layer of readout electronics, in which each 55 μm×55 μm pixel has upper and lower energy discrimination and MHz rate counting. The sensor layer consists of a 300 μm slab of pixellated monolithic silicon and this is bonded to the readout chip. Experimental measurement of the detective quantum efficiency, DQE(0) at 120 keV shows that it can reach 85% independent of electron exposure, since the detector has zero noise, and the DQE(Nyquist) can reach 35% of that expected for a perfect detector (4/π2). Experimental measurement of the modulation transfer function (MTF) at Nyquist resolution for 120 keV electrons using a 60 keV lower energy threshold, yields a value that is 50% of that expected for a perfect detector (2/π). Finally, Monte Carlo simulations of electron tracks and energy deposited in adjacent pixels have been performed and used to calculate expected v...

Seed oil triglyceride profiling of thirty-two hybrid grape varieties.

Science.gov (United States)

De Marchi, Fabiola; Seraglia, Roberta; Molin, Laura; Traldi, Pietro; De Rosso, Mirko; Panighel, Annarita; Dalla Vedova, Antonio; Gardiman, Massimo; Giust, Mirella; Flamini, Riccardo

2012-09-01

Triglyceride profile of seed oil samples from 32 hybrid grape varieties not studied before was investigated. A new method for the analysis of triacylglycerols (TAGs) has been developed based on the direct infusion in the electrospray ionization (ESI) source and employing tetrahydrofuran/methanol/water (85:10:5 v|v|v) as solvent; the formation of [M + Na](+) ions in high yield has been observed. TAGs were identified by ESI-tandem mass spectrometry analysis, and the matrix-assisted-laser-desorption-ionization and time-of-flight profile of samples was determined. Six were the principal TAGs identified in seed oil: trilinolein (LLL) was the most abundant (43%), followed by dilinoleoyl-oleoylglycerol (LOL, 23%), and dilinoleoyl-palmitoylglycerol (LPL, 15%). Compounds present in lower concentration were LSL and LOO (11%), LOP (6%), and LSP (2%). Compared with seed oils produced from V. Vinifera grapes, some significant differences in the relative abundances of TAGs were found, in particular hybrid grape seed oils showed higher LOL and lower LPL content, respectively. Among the samples studied, a particularly high content of LLL (rich in unsaturated fatty acids) was found in seed oils from two red varieties. Copyright © 2012 John Wiley & Sons, Ltd.

Direct Observation of Energy Detrapping in LH1-RC Complex by Two-Dimensional Electronic Spectroscopy.

Science.gov (United States)

Ma, Fei; Yu, Long-Jiang; Hendrikx, Ruud; Wang-Otomo, Zheng-Yu; van Grondelle, Rienk

2017-01-18

The purple bacterial core light harvesting antenna-reaction center (LH1-RC) complex is the simplest system able to achieve the entire primary function of photosynthesis. During the past decade, a variety of photosynthetic proteins were studied by a powerful technique, two-dimensional electronic spectroscopy (2DES). However, little attention has been paid to LH1-RC, although its reversible uphill energy transfer, trapping, and backward detrapping processes, represent a crucial step in the early photosynthetic reaction dynamics. Thus, in this work, we employed 2DES to study two LH1-RC complexes of Thermochromatium (Tch.) tepidum. By direct observation of detrapping, the complex reversible process was clearly identified and an overall scheme of the excitation evolution in LH1-RC was obtained.

Geometric phase and quantum interference in photosynthetic reaction center: Regulation of electron transfer

Energy Technology Data Exchange (ETDEWEB)

Sun, Yuming, E-mail: ymsun@ytu.edu.cn; Su, Yuehua; Dai, Zhenhong; Wang, WeiTian

2016-10-20

Photosynthesis is driven by electron transfer in reaction centers in which the functional unit is composed of several simple molecules C{sub 2}-symmetrically arranged into two branches. In view of quantum mechanism, both branches are possible pathways traversed by the transferred electron. Due to different evolution of spin state along two pathways in transmembrane electric potential (TEP), quantum state of the transferred electron at the bridged site acquires a geometric phase difference dependent on TEP, the most efficient electron transport takes place in a specific range of TEP beyond which electron transfer is dramatically suppressed. What’s more, reaction center acts like elaborately designed quantum device preparing polarized spin dependent on TEP for the transferred electron to regulate the reduction potential at bridged site. In brief, electron transfer generates the TEP, reversely, TEP modulates the efficiency of electron transfer. This may be an important approach to maintaining an appreciable pH environment in photosynthesis.

Two-electron time-delay interference in atomic double ionization by attosecond pulses

Energy Technology Data Exchange (ETDEWEB)

Rescigno, Thomas N

2009-10-04

A two-color two-photon atomic double ionization experiment using subfemtosecond UV pulses can be designed such that the sequential two-color process dominates and one electron is ejected by each pulse. Nonetheless, ab initio calculations show that, for sufficiently short pulses, a prominent interference pattern in the joint energy distribution of the sequentially ejected electrons can be observed that is due to their indistinguishability and the exchange symmetry of the wave function.

Two-Electron Time-Delay Interference in Atomic Double Ionization by Attosecond Pulses

International Nuclear Information System (INIS)

Palacios, A.; Rescigno, T. N.; McCurdy, C. W.

2009-01-01

A two-color two-photon atomic double ionization experiment using subfemtosecond uv pulses can be designed such that the sequential two-color process dominates and one electron is ejected by each pulse. Nonetheless, ab initio calculations show that, for sufficiently short pulses, a prominent interference pattern in the joint energy distribution of the sequentially ejected electrons can be observed that is due to their indistinguishability and the exchange symmetry of the wave function.

Application of two-phase flow for cooling of hybrid microchannel PV cells: A comparative study

International Nuclear Information System (INIS)

Valeh-e-Sheyda, Peyvand; Rahimi, Masoud; Karimi, Ebrahim; Asadi, Masomeh

2013-01-01

Highlights: ► Showing cooling potential of gas–liquid two-phase flow in microchannels for PV cell. ► Introducing the concept of using slug flow in microchannels for cooling of PV cells. ► In single-phase flow, increasing the liquid flow rate enhances the PV power. ► Showing that in two-phase flow the output power related the fluid flow regime. ► By coupling PV and microchannel an increase up to 38% in output power was observed. - Abstract: This paper reports the experimental data from performance of two-phase flows in a small hybrid microchannel solar cell. Using air and water as two-phase fluid, the experiments were conducted at indoor condition in an array of rectangular microchannels with a hydraulic diameter of 0.667 mm. The gas superficial velocity ranges were between 0 and 3.27 m s −1 while liquid flow rate was 0.04 m s −1 . The performance analysis of the PV cell at slug and transitional slug/annular flow regimes are the focus of this study. The influence of two-phase working fluid on PV cell cooling was compared with single-phase. In addition, the great potential of slug flow for heat removal enhancement in PV/T panel was investigated. The obtained data showed the proposed hybrid system could substantially increases the output power of PV solar cells

Hybrid quantum circuit with a superconducting qubit coupled to an electron spin ensemble

Energy Technology Data Exchange (ETDEWEB)

Kubo, Yuimaru; Grezes, Cecile; Vion, Denis; Esteve, Daniel; Bertet, Patrice [Quantronics Group, SPEC (CNRS URA 2464), CEA-Saclay, 91191 Gif-sur-Yvette (France); Diniz, Igor; Auffeves, Alexia [Institut Neel, CNRS, BP 166, 38042 Grenoble (France); Isoya, Jun-ichi [Research Center for Knowledge Communities, University of Tsukuba, 305-8550 Tsukuba (Japan); Jacques, Vincent; Dreau, Anais; Roch, Jean-Francois [LPQM (CNRS, UMR 8537), Ecole Normale Superieure de Cachan, 94235 Cachan (France)

2013-07-01

We report the experimental realization of a hybrid quantum circuit combining a superconducting qubit and an ensemble of electronic spins. The qubit, of the transmon type, is coherently coupled to the spin ensemble consisting of nitrogen-vacancy (NV) centers in a diamond crystal via a frequency-tunable superconducting resonator acting as a quantum bus. Using this circuit, we prepare arbitrary superpositions of the qubit states that we store into collective excitations of the spin ensemble and retrieve back into the qubit. We also report a new method for detecting the magnetic resonance of electronic spins at low temperature with a qubit using the hybrid quantum circuit, as well as our recent progress on spin echo experiments.

Two-dimensional electron gas in monolayer InN quantum wells

International Nuclear Information System (INIS)

Pan, W.; Wang, G. T.; Dimakis, E.; Moustakas, T. D.; Tsui, D. C.

2014-01-01

We report in this letter experimental results that confirm the two-dimensional nature of the electron systems in a superlattice structure of 40 InN quantum wells consisting of one monolayer of InN embedded between 10 nm GaN barriers. The electron density and mobility of the two-dimensional electron system (2DES) in these InN quantum wells are 5 × 10 15  cm −2 (or 1.25 × 10 14  cm −2 per InN quantum well, assuming all the quantum wells are connected by diffused indium contacts) and 420 cm 2 /Vs, respectively. Moreover, the diagonal resistance of the 2DES shows virtually no temperature dependence in a wide temperature range, indicating the topological nature of the 2DES

Two-dimensional electron flow in pulsed power transmission lines and plasma opening switches

International Nuclear Information System (INIS)

Church, B.W.; Longcope, D.W.; Ng, C.K.; Sudan, R.N.

1991-01-01

The operation of magnetically insulated transmission lines (MITL) and the interruption of current in a plasma opening switch (POS) are determined by the physics of the electrons emitted by the cathode surface. A mathematical model describes the self-consistent two-dimensional flow of an electron fluid. A finite element code, FERUS, has been developed to solve the two equations which describe Poisson's and Ampere's law in two dimensions. The solutions from this code are obtained for parameters where the electron orbits are considerably modified by the self-magnetic field of the current. Next, the self-insulated electron flow in a MITL with a step change in cross-section is studied using a conventional two-dimensional fully electromagnetic particle-in-cell code, MASK. The equations governing two-dimensional quasi-static electron flow are solved numerically by a third technique which is suitable for predicting current interruption in a POS. The object of the study is to determine the critical load impedance, Z CL , required for current interruption for a given applied voltage, cathode voltage and plasma length. (author). 9 refs, 5 figs

Load estimator-based hybrid controller design for two-interleaved boost converter dedicated to renewable energy and automotive applications.

Science.gov (United States)

Bougrine, Mohamed; Benmiloud, Mohammed; Benalia, Atallah; Delaleau, Emmanuel; Benbouzid, Mohamed

2017-01-01

This paper is devoted to the development of a hybrid controller for a two-interleaved boost converter dedicated to renewable energy and automotive applications. The control requirements, resumed in fast transient and low input current ripple, are formulated as a problem of fast stabilization of a predefined optimal limit cycle, and solved using hybrid automaton formalism. In addition, a real time estimation of the load is developed using an algebraic approach for online adjustment of the hybrid controller. Mathematical proofs are provided with simulations to illustrate the effectiveness and the robustness of the proposed controller despite different disturbances. Furthermore, a fuel cell system supplying a resistive load through a two-interleaved boost converter is also highlighted. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Alternative Fuels Data Center: Hybrid and Electric Vehicles Boom Coast to

Science.gov (United States)

Coast Hybrid and Electric Vehicles Boom Coast to Coast to someone by E-mail Share Alternative Fuels Data Center: Hybrid and Electric Vehicles Boom Coast to Coast on Facebook Tweet about Alternative Fuels Data Center: Hybrid and Electric Vehicles Boom Coast to Coast on Twitter Bookmark Alternative

A Two-Phase Coverage-Enhancing Algorithm for Hybrid Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Qingguo Zhang

2017-01-01

Full Text Available Providing field coverage is a key task in many sensor network applications. In certain scenarios, the sensor field may have coverage holes due to random initial deployment of sensors; thus, the desired level of coverage cannot be achieved. A hybrid wireless sensor network is a cost-effective solution to this problem, which is achieved by repositioning a portion of the mobile sensors in the network to meet the network coverage requirement. This paper investigates how to redeploy mobile sensor nodes to improve network coverage in hybrid wireless sensor networks. We propose a two-phase coverage-enhancing algorithm for hybrid wireless sensor networks. In phase one, we use a differential evolution algorithm to compute the candidate’s target positions in the mobile sensor nodes that could potentially improve coverage. In the second phase, we use an optimization scheme on the candidate’s target positions calculated from phase one to reduce the accumulated potential moving distance of mobile sensors, such that the exact mobile sensor nodes that need to be moved as well as their final target positions can be determined. Experimental results show that the proposed algorithm provided significant improvement in terms of area coverage rate, average moving distance, area coverage–distance rate and the number of moved mobile sensors, when compare with other approaches.

G-centers in irradiated silicon revisited: A screened hybrid density functional theory approach

KAUST Repository

Wang, H.

2014-05-13

Electronic structure calculations employing screened hybrid density functional theory are used to gain fundamental insight into the interaction of carbon interstitial (Ci) and substitutional (Cs) atoms forming the CiCs defect known as G-center in silicon (Si). The G-center is one of the most important radiation related defects in Czochralski grown Si. We systematically investigate the density of states and formation energy for different types of CiCs defects with respect to the Fermi energy for all possible charge states. Prevalence of the neutral state for the C-type defect is established.

Two-site Hubbard molecule with a spinless electron-positron pair

KAUST Repository

Cossu, Fabrizio

2012-12-19

We determine the eigenvalues of the two-site Hubbard molecule with one electron and one positron to describe the characteristics of electron-positron interactions in solids. While the effect of hopping is, in general, opposite to the effect of on-site interaction, we find a complex scenario for the electron-positron pair with a non-vanishing potential drop. We give analytical solutions and discuss the combined effects of the model parameters.

Two-site Hubbard molecule with a spinless electron-positron pair

KAUST Repository

Cossu, Fabrizio; Schuster, Cosima; Schwingenschlö gl, Udo

2012-01-01

We determine the eigenvalues of the two-site Hubbard molecule with one electron and one positron to describe the characteristics of electron-positron interactions in solids. While the effect of hopping is, in general, opposite to the effect of on-site interaction, we find a complex scenario for the electron-positron pair with a non-vanishing potential drop. We give analytical solutions and discuss the combined effects of the model parameters.

Torn Between Two Worlds: Hybridity and In-between Identity Recognition in Goli Taraqqi’s Two Worlds

Directory of Open Access Journals (Sweden)

Nasser Najafi Shabankare

2014-10-01

Full Text Available As one of the contemporary Iranian women writers living in the U.S, Goli Taraqqi’s fiction is mostly concerned with pains and difficulties of migrant Iranian women in other countries. Bearing a biographical resemblance, her sequence collection to Scattered Memories, entitled Two Worlds retells interrelated short stories of a woman writer narrator, entangled in an asylum in Paris, who digs into her past, writes stories about it, and is able to regain her sanity in the end, as she gets ready to enter the brave new world. The process of identity recognition is to be approached with an eye on Homi K, Bhabha’s assertions about ‘hybridity’ and ‘in-between’ as explained in his 1994 Location and Culture, to see to what degree the newly gained identity, which is resembled to a resurrection, is in fact a hybrid one.

Two-step excitation structure changes of luminescence centers and strong tunable blue emission on surface of silica nanospheres

Energy Technology Data Exchange (ETDEWEB)

Yang, Lei, E-mail: nanoyang@qq.com; Jiang, Zhongcheng; Dong, Jiazhang; Zhang, Liuqian [Hunan University, College of Materials Science and Engineering (China); Pan, Anlian, E-mail: anlian.pan@gmail.com; Zhuang, Xiujuan [Hunan University, Key Laboratory for Micro-Nano Physics and Technology of Hunan Province (China)

2015-10-15

We report a scheme for investigating two-step stimulated structure change of luminescence centers. Amorphous silica nanospheres with uniform diameter of 9–15 nm have been synthesized by Stöber method. Strong hydroxyl-related infrared-absorption band is observed in infrared spectrum. The surface hydroxyl groups exert great influence on the luminescent behavior of silica. They provide stable and intermediate energy states to accommodate excitation electrons. The existence of these surface states reduces the energy barrier of photochemical reactions, creating conditions for two-step excitation process. By carefully examining excitation and emission process, the nearest excitation band is absent in both optical absorption spectrum and excitation spectrum. This later generated state confirms the generation of new luminescence centers as well as the existence of photochemical reactions. Stimulated by different energies, two-step excitation process impels different photochemical reactions, prompting generation of different lattice defects on surface area of silica. Thereby, tunable luminescence is achieved. After thermal treatment, strong gap excitation band appears with the disappearance of strong surface excitation band. Strong blue luminescence also disappears. The research is significance to precise introducing structural defects and controlling position of luminescence peaks.

Investigation of Fanconi anemia protein interactions by yeast two-hybrid analysis.

Science.gov (United States)

Huber, P A; Medhurst, A L; Youssoufian, H; Mathew, C G

2000-02-05

Fanconi anemia is a chromosomal breakage disorder with eight complementation groups (A-H), and three genes (FANCA, FANCC, and FANCG) have been identified. Initial investigations of the interaction between FANCA and FANCC, principally by co-immunoprecipitation, have proved controversial. We used the yeast two-hybrid assay to test for interactions of the FANCA, FANCC, and FANCG proteins. No activation of the reporter gene was observed in yeast co-expressing FANCA and FANCC as hybrid proteins, suggesting that FANCA does not directly interact with FANCC. However, a high level of activation was found when FANCA was co-expressed with FANCG, indicating strong, direct interaction between these proteins. Both FANCA and FANCG show weak but consistent interaction with themselves, suggesting that their function may involve dimerisation. The site of interaction of FANCG with FANCA was investigated by analysis of 12 mutant fragments of FANCG. Although both N- and C-terminal fragments did interact, binding to FANCA was drastically reduced, suggesting that more than one region of the FANCG protein is required for proper interaction with FANCA. Copyright 2000 Academic Press.

Graviton production by two photon and electron-photon processes in Kaluza-Klein theories with large extra dimensions

International Nuclear Information System (INIS)

Atwood, David; Bar-Shalom, Shaouly; Soni, Amarjit

2000-01-01

We consider the production of gravitons via two photon and electron-photon fusion in Kaluza-Klein theories which allow TeV scale gravitational interactions. We show that at electron-positron colliders, the processes l + l - →l + l - +graviton, with l=e, μ, can lead to a new signal of low energy gravity of the form l + l - →l + l - +missing energy which is well above the standard model background. For example, with two extra dimensions, at the Next Linear Collider with a center of mass energy of 500 or 1000 GeV, hundreds to thousands such l + l - +graviton events may be produced if the scale of the gravitational interactions, M D , is around a few TeV. At a gamma-electron collider, more stringent bounds may be placed on M D via the related reaction e - γ→e - G. For instance, if a 1 TeV e + e - collider is converted to an electron-photon collider, a bound of ∼10(14) TeV may be placed on the scale M D if the number of extra dimensions δ=2, while a bound of ∼4(5) TeV may be placed if δ=4, with unpolarized (right polarized) electron beams. (c) 2000 The American Physical Society

Electron-neutrino scattering off nuclei from two different theoretical perspectives

Science.gov (United States)

Martini, M.; Jachowicz, N.; Ericson, M.; Pandey, V.; Van Cuyck, T.; Van Dessel, N.

2016-07-01

We analyze charged-current electron-neutrino cross sections on carbon. We consider two different theoretical approaches, on one hand the continuum random phase approximation (CRPA) which allows a description of giant resonances and quasielastic excitations, on the other hand the RPA-based calculations which are able to describe multinucleon emission and coherent and incoherent pion production as well as quasielastic excitations. We compare the two approaches in the genuine quasielastic channel, and find a satisfactory agreement between them at large energies while at low energies the collective giant resonances show up only in the CRPA approach. We also compare electron-neutrino cross sections with the corresponding muon-neutrino ones in order to investigate the impact of the different charged-lepton masses. Finally, restricting to the RPA-based approach, we compare the sum of quasielastic, multinucleon emission, coherent, and incoherent one-pion production cross sections (folded with the electron-neutrino T2K flux) with the charged-current inclusive electron-neutrino differential cross sections on carbon measured by T2K. We find a good agreement with the data. The multinucleon component is needed in order to reproduce the T2K electron-neutrino inclusive cross sections.

Binding of two-electron metastable states in semiconductor quantum dots under a magnetic field

Science.gov (United States)

Garagiola, Mariano; Pont, Federico M.; Osenda, Omar

2018-04-01

Applying a strong enough magnetic field results in the binding of few-electron resonant states. The mechanism was proposed many years ago but its verification in laboratory conditions is far more recent. In this work we study the binding of two-electron resonant states. The electrons are confined in a cylindrical quantum dot which is embedded in a semiconductor wire. The geometry considered is similar to the one used in actual experimental setups. The low-energy two-electron spectrum is calculated numerically from an effective-mass approximation Hamiltonian modelling the system. Methods for binding threshold calculations in systems with one and two electrons are thoroughly studied; in particular, we use quantum information quantities to assess when the strong lateral confinement approximation can be used to obtain reliable low-energy spectra. For simplicity, only cases without bound states in the absence of an external field are considered. Under these conditions, the binding threshold for the one-electron case is given by the lowest Landau energy level. Moreover, the energy of the one-electron bounded resonance can be used to obtain the two-electron binding threshold. It is shown that for realistic values of the two-electron model parameters it is feasible to bind resonances with field strengths of a few tens of tesla.

The development of two-phase flow instrumentation at PNC O-arai Engineering Center

International Nuclear Information System (INIS)

Obata, T.; Kobori, T.; Hayamizu, Y.

1975-10-01

This paper reviews development works on the two-phase flow instrumentation carried out at PNC Oarai Engineering Center for FUGEN safety test. The paper describes heater surface temperature measurement, four types of void meters and two steam quality meters. (auth.)

[Identification of C(2)M interacting proteins by yeast two-hybrid screening].

Science.gov (United States)

Yue, Shan-shan; Xia, Lai-xin

2015-11-01

The synaptonemal complex (SC) is a huge structure which assembles between the homologous chromosomes during meiotic prophase I. Drosophila germ cell-specific nucleoprotein C(2)M clustering at chromosomes can induce SC formation. To further study the molecular function and mechanism of C(2)M in meiosis, we constructed a bait vector for C(2)M and used the yeast two-hybrid system to identify C(2)M interacting proteins. Forty interacting proteins were obtained, including many DNA and histone binding proteins, ATP synthases and transcription factors. Gene silencing assays in Drosophila showed that two genes, wech and Psf1, may delay the disappearance of SC. These results indicate that Wech and Psf1 may form a complex with C(2)M to participate in the formation or stabilization of the SC complex.

Fecal coliforms on environmental surfaces in two day care centers.

Science.gov (United States)

Weniger, B G; Ruttenber, A J; Goodman, R A; Juranek, D D; Wahlquist, S P; Smith, J D

1983-01-01

A survey of environmental surfaces in two Atlanta area day care centers was conducted to determine the prevalence of fecal coliform bacteria, considered a marker for the presence of fecal contamination which might contain pathogenic parasites, bacteria, or viruses. Fecal coliforms were found in 17 (4.3%) of 398 representative samples of building surfaces, furniture, and other objects. These surfaces may be involved in the chain of transmission of enteric diseases among children. Therefore, disinfection of inanimate objects, in addition to good handwashing, may be important in controlling the spread of enteric diseases in day care centers. PMID:6830225

Zero-point energies in the two-center shell model. II

International Nuclear Information System (INIS)

Reinhard, P.-G.

1978-01-01

The zero-point energy (ZPE) contained in the potential-energy surface of a two-center shell model (TCSM) is evaluated. In extension of previous work, the author uses here the full TCSM with l.s force, smoothing and asymmetry. The results show a critical dependence on the height of the potential barrier between the centers. The ZPE turns out to be non-negligible along the fission path for 236 U, and even more so for lighter systems. It is negligible for surface quadrupole motion and it is just on the fringe of being negligible for motion along the asymmetry coordinate. (Auth.)

Information systems performance evaluation, introducing a two-level technique: Case study call centers

Directory of Open Access Journals (Sweden)

Hesham A. Baraka

2015-03-01

The objective of this paper was to introduce a new technique that can support decision makers in the call centers industry to evaluate, and analyze the performance of call centers. The technique presented is derived from the research done on measuring the success or failure of information systems. Two models are mainly adopted namely: the Delone and Mclean model first introduced in 1992 and the Design Reality Gap model introduced by Heeks in 2002. Two indices are defined to calculate the performance of the call center; the success index and the Gap Index. An evaluation tool has been developed to allow call centers managers to evaluate the performance of their call centers in a systematic analytical approach; the tool was applied on 4 call centers from different areas, simple applications such as food ordering, marketing, and sales, technical support systems, to more real time services such as the example of emergency control systems. Results showed the importance of using information systems models to evaluate complex systems as call centers. The models used allow identifying the dimensions for the call centers that are facing challenges, together with an identification of the individual indicators in these dimensions that are causing the poor performance of the call center.

Focal epilepsies in adult patients attending two epilepsy centers

DEFF Research Database (Denmark)

Gilioli, Isabella; Vignoli, Aglaia; Visani, Elisa

2012-01-01

, and we evaluated the risk factors associated with AED resistance using logistic regression analysis. We further grouped AED-resistant patients in different grades (I, II, and III) according to the number of AEDs already tried as proposed by Perucca. KEY FINDINGS: AED resistance occurred in 57...... consecutively after 1990 and followed regularly at two epilepsy centers. We systematically collected the clinical, diagnostic, and therapeutic data using a custom-written database. We classified the patients as seizure-free or AED resistant according to the International League Against Epilepsy (ILAE) criteria...... control (14.9% needed three or more AEDs). Furthermore, among seizure-free patients who could be previously classified as resistant to two or more AEDs, 52.2% reached seizure freedom while receiving treatment with "new generation" AEDs. SIGNIFICANCE: The ILAE classification of AED resistance, as well...

Hybrid biogas upgrading in a two-stage thermophilic reactor

DEFF Research Database (Denmark)

Corbellini, Viola; Kougias, Panagiotis; Treu, Laura

2018-01-01

The aim of this study is to propose a hybrid biogas upgrading configuration composed of two-stage thermophilic reactors. Hydrogen is directly injected in the first stage reactor. The output gas from the first reactor (in-situ biogas upgrade) is subsequently transferred to a second upflow reactor...... (ex-situ upgrade), in which enriched hydrogenotrophic culture is responsible for the hydrogenation of carbon dioxide to methane. The overall objective of the work was to perform an initial methane enrichment in the in-situ reactor, avoiding deterioration of the process due to elevated pH levels......, and subsequently, to complete the biogas upgrading process in the ex-situ chamber. The methane content in the first stage reactor reached on average 87% and the corresponding value in the second stage was 91%, with a maximum of 95%. A remarkable accumulation of volatile fatty acids was observed in the first...

Kinetics of two-dimensional electron plasma, interacting with fluctuating potential

International Nuclear Information System (INIS)

Boiko, I.I.; Sirenko, Y.M.

1990-01-01

In this paper, from the first principles, after the fashion of Klimontovich, the authors derive quantum kinetic equation for electron gas, inhomogeneous in z-direction and homogeneous in XY-plane. Special attention is given to the systems with quasi-two-dimensional electron gas (2 DEG), which are widely explored now. Both interaction between the particles of 2 DEG (in general, of several sorts), and interaction with an external system (phonons, impurities, after change carries etc.) are considered. General theory is used to obtain energy and momentum balance equations and relaxation frequencies for 2 DEG in the basis of plane waves. The case of crossed electric and magnetic fields is also treated. As an illustration the problems of 2 DEG scattering on semibounded three-dimensional electron gas and on two-dimensional hole gas are considered; transverse conductivity of nondegenerate 2 DEG, scattered by impurities in ultraquantum magnetic field, is calculated

Metallic and highly conducting two-dimensional atomic arrays of sulfur enabled by molybdenum disulfide nanotemplate

Science.gov (United States)

Zhu, Shuze; Geng, Xiumei; Han, Yang; Benamara, Mourad; Chen, Liao; Li, Jingxiao; Bilgin, Ismail; Zhu, Hongli

2017-10-01

Element sulfur in nature is an insulating solid. While it has been tested that one-dimensional sulfur chain is metallic and conducting, the investigation on two-dimensional sulfur remains elusive. We report that molybdenum disulfide layers are able to serve as the nanotemplate to facilitate the formation of two-dimensional sulfur. Density functional theory calculations suggest that confined in-between layers of molybdenum disulfide, sulfur atoms are able to form two-dimensional triangular arrays that are highly metallic. As a result, these arrays contribute to the high conductivity and metallic phase of the hybrid structures of molybdenum disulfide layers and two-dimensional sulfur arrays. The experimentally measured conductivity of such hybrid structures reaches up to 223 S/m. Multiple experimental results, including X-ray photoelectron spectroscopy (XPS), transition electron microscope (TEM), selected area electron diffraction (SAED), agree with the computational insights. Due to the excellent conductivity, the current density is linearly proportional to the scan rate until 30,000 mV s-1 without the attendance of conductive additives. Using such hybrid structures as electrode, the two-electrode supercapacitor cells yield a power density of 106 Wh kg-1 and energy density 47.5 Wh kg-1 in ionic liquid electrolytes. Our findings offer new insights into using two-dimensional materials and their Van der Waals heterostructures as nanotemplates to pattern foreign atoms for unprecedented material properties.

Electron-positron pair production by two identical photons in the nuclear field

International Nuclear Information System (INIS)

Smirnov, A.I.

1977-01-01

In the Born approximation of the perturbation theory considered is a nonlinear effect of the electron-positron pair production by two identical photons in the Coulomb field of an atomic nucleus. The kinematic version of identical photons is studied. All the particles are considered to be nonpolarized. The calculation of the differential probability of the effect has been carried out earlier by the Feynman method. The total probability of the effect in limiting energy ranges is determined by integrating the formulas of the pair component distribution over energies. The probabilities of the electron-positron pair production and fusion of two photons into one in the nucleus field have been compared for the case of identical quanta. From the comparison of the results of analyzing both the nonlinear effects it follows that in the high-energy range the electron-positron pair production by two identical photons in the nucleus field extremely predominates over the fusion of two photons into one photon in the same field

Numerical simulation of a theta-pinch: two-dimensional hybrid model

International Nuclear Information System (INIS)

Zenum, C.S.S.

1987-01-01

A numerical code based on a 2D-hybrid model, were the electrons are considered as a fluid of zero mass and the ions as discrete particles, was elaborated. The magnetic field responsable by ion acceleration was obtained from equation of motion of the electrons and Maxwell equations. The ions are randomly distributed in a space phase of five dimensions (Vr, Vo, Vz, r, z), according to the Maxwellian. The equation of motion is solved for each ion, and the distribution functions of ion is obtained by the technique of particle into the box. The resistivity was classically and phenomenologically treated. The model was applied to theta-pinch to study: the plasma physical behaviour during the phase of implosion; the effect of reflected ions by magnetic piston; and the effect of magnetic field line reconnection 3D graphics of magnetic field, electric field current density, particle, and pressure densities, electron temperature, ion temperature is presented space phase of ion velocity in function of the position is also shown. The obtained results allow to characterized the obtained phenomena which occur during the phase of implosion. (M.C.K.) [pt

Electron transfer by excited benzoquinone anions: slow rates for two-electron transitions.

Science.gov (United States)

Zamadar, Matibur; Cook, Andrew R; Lewandowska-Andralojc, Anna; Holroyd, Richard; Jiang, Yan; Bikalis, Jin; Miller, John R

2013-09-05

Electron transfer (ET) rate constants from the lowest excited state of the radical anion of benzoquinone, BQ(-•)*, were measured in THF solution. Rate constants for bimolecular electron transfer reactions typically reach the diffusion-controlled limit when the free-energy change, ΔG°, reaches -0.3 eV. The rate constants for ET from BQ(-•)* are one-to-two decades smaller at this energy and do not reach the diffusion-controlled limit until -ΔG° is 1.5-2.0 eV. The rates are so slow probably because a second electron must also undergo a transition to make use of the energy of the excited state. Similarly, ET, from solvated electrons to neutral BQ to form the lowest excited state, is slow, while fast ET is observed at a higher excited state, which can be populated in a transition involving only one electron. A simple picture based on perturbation theory can roughly account for the control of electron transfer by the need for transition of a second electron. The picture also explains how extra driving force (-ΔG°) can restore fast rates of electron transfer.

Natural hybridization and asymmetric introgression at the distribution margin of two Buddleja species with a large overlap.

Science.gov (United States)

Liao, Rong-Li; Ma, Yong-Peng; Gong, Wei-Chang; Chen, Gao; Sun, Wei-Bang; Zhou, Ren-Chao; Marczewski, Tobias

2015-06-18

Natural hybridization in plants is universal and plays an important role in evolution. Based on morphology it has been presumed that hybridization occurred in the genus Buddleja, though genetic studies confirming this assumption have not been conducted to date. The two species B. crispa and B. officinalis overlap in their distributions over a wide range in South-West China, and we aimed to provide genetic evidence for ongoing hybridization in this study. We investigated the occurrence of hybrids between the two species at the southern-most edge of the distribution of B. crispa using five nuclear loci and pollination experiments. The genetic data suggest substantial differentiation between the two species as species-specific alleles are separated by at least 7-28 mutations. The natural hybrids found were nearly all F1s (21 of 23), but backcrosses were detected, and some individuals, morphologically indistinguishable from the parental species, showed introgression. Pollen viability test shows that the percentage of viable pollen grains was 50 ± 4% for B. crispa, and 81 ± 2% for B. officinalis. This difference is highly significant (t = 7.382, p < 0.0001). Hand cross-pollination experiments showed that B. crispa is not successful as pollen-parent, but B. officinalis is able to pollinate B. crispa to produce viable hybrid seed. Inter-specific seed-set is low (8 seeds per fruit, as opposed to about 65 for intra-specific pollinations), suggesting post-zygotic reproductive barriers. In addition, one of the reference populations also suggests a history of introgression at other localities. The occurrence of morphologically intermediate individuals between B. crispa and B. officinalis at Xishan Mountain is unequivocally linked to hybridization and almost all examined individuals of the putative hybrids were likely F1s. Despite pollination experiments indicating higher chances for introgression into B. officinalis (hybrids only produced viable seed when

Magnetic phase transition induced by electrostatic gating in two-dimensional square metal-organic frameworks

Science.gov (United States)

Wang, Yun-Peng; Li, Xiang-Guo; Liu, Shuang-Long; Fry, James N.; Cheng, Hai-Ping

2018-03-01

We investigate theoretically magnetism and magnetic phase transitions induced by electrostatic gating of two-dimensional square metal-organic framework compounds. We find that electrostatic gating can induce phase transitions between homogeneous ferromagnetic and various spin-textured antiferromagnetic states. Electronic structure and Wannier function analysis can reveal hybridizations between transition-metal d orbitals and conjugated π orbitals in the organic framework. Mn-containing compounds exhibit a strong d -π hybridization that leads to partially occupied spin-minority bands, in contrast to compounds containing transition-metal ions other than Mn, for which electronic structure around the Fermi energy is only slightly spin split due to weak d -π hybridization and the magnetic interaction is of the Ruderman-Kittel-Kasuya-Yosida type. We use a ferromagnetic Kondo lattice model to understand the phase transition in Mn-containing compounds in terms of carrier density and illuminate the complexity and the potential to control two-dimensional magnetization.

Structure of compensating centers in neutron irradiated n-type germanium

International Nuclear Information System (INIS)

Erchak, D.P.; Kosobutskij, V.S.; Stel'makh, V.F.

1989-01-01

Structural model of one of the main compensating defects of Ge-M1, Ge-M5, Ge-M6 in neutron irradiated (10 18 -10 20 cm -2 ) germanium, strongly alloyed (2x10 18 -3x10 19 cm -3 ) with antimony, phosphorus and arsenic respectively, is suggested. The above mentioned compensating centers are paramagnetic in a positive charge state and represent a vacancy, two nearby germanium atoms of which are replaced with two atoms of corresponding fine donor impurity. It is mainly contributed (63%- for Ge-M5 centers, 56% - for Ge-M6 centers) by orbitals of two germanium atoms neighbouring the vacancy. The angle of the bonds of each of two mentioned germanium atoms with its three neighbours and orientation of maximum electron density of hybride orbital, binding both germanium atoms, is approximately by 5 deg greater the tetrahedral one

Local energy equation for two-electron atoms and relation between kinetic energy and electron densities

International Nuclear Information System (INIS)

March, N.H.

2002-08-01

In early work, Dawson and March [J. Chem. Phys. 81, 5850 (1984)] proposed a local energy method for treating both Hartree-Fock and correlated electron theory. Here, an exactly solvable model two-electron atom with pure harmonic interactions is treated in its ground state in the above context. A functional relation between the kinetic energy density t(r) at the origin r=0 and the electron density p(r) at the same point then emerges. The same approach is applied to the Hookean atom; in which the two electrons repel with Coulombic energy e 2 /r 12 , with r 12 the interelectronic separation, but are still harmonically confined. Again the kinetic energy density t(r) is the focal point, but now generalization away from r=0 is also effected. Finally, brief comments are added about He-like atomic ions in the limit of large atomic number. (author)

DFT and two-dimensional correlation analysis methods for evaluating the Pu3+–Pu4+ electronic transition of plutonium-doped zircon

International Nuclear Information System (INIS)

Bian, Liang; Dong, Fa-qin; Song, Mian-xin; Dong, Hai-liang; Li, Wei-Min; Duan, Tao; Xu, Jin-bao; Zhang, Xiao-yan

2015-01-01

Highlights: • Effect of Pu f-shell electron on the electronic property of zircon is calculated via DFT and 2D-CA techniques. • Reasons of Pu f-shell electron influencing on electronic properties are systematically discussed. • Phase transitions are found at two point 2.8 mol% and 7.5 mol%. - Abstract: Understanding how plutonium (Pu) doping affects the crystalline zircon structure is very important for risk management. However, so far, there have been only a very limited number of reports of the quantitative simulation of the effects of the Pu charge and concentration on the phase transition. In this study, we used density functional theory (DFT), virtual crystal approximation (VCA), and two-dimensional correlation analysis (2D-CA) techniques to calculate the origins of the structural and electronic transitions of Zr 1−c Pu c SiO 4 over a wide range of Pu doping concentrations (c = 0–10 mol%). The calculations indicated that the low-angular-momentum Pu-f xy -shell electron excites an inner-shell O-2s 2 orbital to create an oxygen defect (V O-s ) below c = 2.8 mol%. This oxygen defect then captures a low-angular-momentum Zr-5p 6 5s 2 electron to form an sp hybrid orbital, which exhibits a stable phase structure. When c > 2.8 mol%, each accumulated V O-p defect captures a high-angular-momentum Zr-4d z electron and two Si-p z electrons to create delocalized Si 4+ → Si 2+ charge disproportionation. Therefore, we suggest that the optimal amount of Pu cannot exceed 7.5 mol% because of the formation of a mixture of ZrO 8 polyhedral and SiO 4 tetrahedral phases with the orientation (10-1). This study offers new perspective on the development of highly stable zircon-based solid solution materials

Genomic change, retrotransposon mobilization and extensive cytosine methylation alteration in Brassica napus introgressions from two intertribal hybridizations.

Science.gov (United States)

Zhang, Xueli; Ge, Xianhong; Shao, Yujiao; Sun, Genlou; Li, Zaiyun

2013-01-01

Hybridization and introgression represent important means for the transfer and/or de novo origination of traits and play an important role in facilitating speciation and plant breeding. Two sets of introgression lines in Brassica napus L. were previously established by its intertribal hybridizations with two wild species and long-term selection. In this study, the methods of amplified fragment length polymorphisms (AFLP), sequence-specific amplification polymorphism (SSAP) and methylation-sensitive amplified polymorphism (MSAP) were used to determine their genomic change, retrotransposon mobilization and cytosine methylation alteration in these lines. The genomic change revealed by the loss or gain of AFLP bands occurred for ∼10% of the total bands amplified in the two sets of introgressions, while no bands specific for wild species were detected. The new and absent SSAP bands appeared for 9 out of 11 retrotransposons analyzed, with low frequency of new bands and their total percentage of about 5% in both sets. MSAP analysis indicated that methylation changes were common in these lines (33.4-39.8%) and the hypermethylation was more frequent than hypomethylation. Our results suggested that certain extents of genetic and epigenetic alterations were induced by hybridization and alien DNA introgression. The cryptic mechanism of these changes and potential application of these lines in breeding were also discussed.

High-Resolution Two-Dimensional Optical Spectroscopy of Electron Spins

Directory of Open Access Journals (Sweden)

M. Salewski

2017-08-01

Full Text Available Multidimensional coherent optical spectroscopy is one of the most powerful tools for investigating complex quantum mechanical systems. While it was conceived decades ago in magnetic resonance spectroscopy using microwaves and radio waves, it has recently been extended into the visible and UV spectral range. However, resolving MHz energy splittings with ultrashort laser pulses still remains a challenge. Here, we analyze two-dimensional Fourier spectra for resonant optical excitation of resident electrons to localized trions or donor-bound excitons in semiconductor nanostructures subject to a transverse magnetic field. Particular attention is devoted to Raman coherence spectra, which allow one to accurately evaluate tiny splittings of the electron ground state and to determine the relaxation times in the electron spin ensemble. A stimulated steplike Raman process induced by a sequence of two laser pulses creates a coherent superposition of the ground-state doublet which can be retrieved only optically because of selective excitation of the same subensemble with a third pulse. This provides the unique opportunity to distinguish between different complexes that are closely spaced in energy in an ensemble. The related experimental demonstration is based on photon-echo measurements in an n-type CdTe/(Cd,MgTe quantum-well structure detected by a heterodyne technique. The difference in the sub-μeV range between the Zeeman splittings of donor-bound electrons and electrons localized at potential fluctuations can be resolved even though the homogeneous linewidth of the optical transitions is larger by 2 orders of magnitude.

Electron-neutrino scattering off nuclei from two different theoretical perspectives

CERN Document Server

Martini, M.; Ericson, M.; Pandey, V.; Van Cuyck, T.; Van Dessel, N.

2016-01-01

We analyze charged-current electron-neutrino cross sections on Carbon. We consider two different theoretical approaches, on one hand the Continuum Random Phase Approximation (CRPA) which allows a description of giant resonances and quasielastic excitations, on the other hand the RPA-based calculations which are able to describe multinucleon emission and coherent and incoherent pion production as well as quasielastic excitations. We compare the two approaches in the genuine quasielastic channel, and find a satisfactory agreement between them at large energies while at low energies the collective giant resonances show up only in the CRPA approach. We also compare electron-neutrino cross sections with the corresponding muon-neutrino ones in order to investigate the impact of the different charged-lepton masses. Finally, restricting to the RPA-based approach we compare the sum of quasielastic, multinucleon emission, coherent and incoherent one-pion production cross sections (folded with the electron-neutrino T2K ...

Phenology, sterility and inheritance of two environment genic male sterile (EGMS) lines for hybrid rice.

Science.gov (United States)

El-Namaky, R; van Oort, P A J

2017-12-01

There is still limited quantitative understanding of how environmental factors affect sterility of Environment-conditioned genic male sterility (EGMS) lines. A model was developed for this purpose and tested based on experimental data from Ndiaye (Senegal) in 2013-2015. For the two EGMS lines tested here, it was not clear if one or more recessive gene(s) were causing male sterility. This was tested by studying sterility segregation of the F2 populations. Daylength (photoperiod) and minimum temperatures during the period from panicle initiation to flowering had significant effects on male sterility. Results clearly showed that only one recessive gene was involved in causing male sterility. The model was applied to determine the set of sowing dates of two different EGMS lines such that both would flower at the same time the pollen would be completely sterile. In the same time the local popular variety (Sahel 108, the male pollen donor) being sufficiently fertile to produce the hybrid seeds. The model was applied to investigate the viability of the two line breeding system in the same location with climate change (+2oC) and in two other potential locations: in M'Be in Ivory Coast and in the Nile delta in Egypt. Apart from giving new insights in the relation between environment and EGMS, this study shows that these insights can be used to assess safe sowing windows and assess the suitability of sterility and fertility period of different environments for a two line hybrid rice production system.

Interaction of two solitary waves in quantum electron-positron-ion plasma

International Nuclear Information System (INIS)

Xu Yanxia; Lin Maimai; Shi Yuren; Duan Wenshan; Liu Zongming; Chen Jianmin

2011-01-01

The collision between two ion-acoustic solitary waves with arbitrary colliding angle θ in an unmagnetized, ultracold quantum three-component e-p-i plasma has been investigated. By using the extended Poincare-Lighthill-Kuo (PLK) perturbation method, we obtain the KdV equations and the analytical phase shifts after the collision of two solitary waves in this three-component plasma. The effects of the quantum parameter H, the ratio of Fermi positron temperature to Fermi electron temperature σ, the ratio of Fermi positron number density to Fermi electron number density μ, and the ratio of Fermi ion temperature to Fermi electron temperature ρ on the phase shifts are studied. It is found that these parameters can significantly influence the phase shifts of the solitons.

Genomic islands of differentiation in two songbird species reveal candidate genes for hybrid female sterility.

Science.gov (United States)

Mořkovský, Libor; Janoušek, Václav; Reif, Jiří; Rídl, Jakub; Pačes, Jan; Choleva, Lukáš; Janko, Karel; Nachman, Michael W; Reifová, Radka

2018-02-01

Hybrid sterility is a common first step in the evolution of postzygotic reproductive isolation. According to Haldane's Rule, it affects predominantly the heterogametic sex. While the genetic basis of hybrid male sterility in organisms with heterogametic males has been studied for decades, the genetic basis of hybrid female sterility in organisms with heterogametic females has received much less attention. We investigated the genetic basis of reproductive isolation in two closely related avian species, the common nightingale (Luscinia megarhynchos) and the thrush nightingale (L. luscinia), that hybridize in a secondary contact zone and produce viable hybrid progeny. In accordance with Haldane's Rule, hybrid females are sterile, while hybrid males are fertile, allowing gene flow to occur between the species. Using transcriptomic data from multiple individuals of both nightingale species, we identified genomic islands of high differentiation (F ST ) and of high divergence (D xy ), and we analysed gene content and patterns of molecular evolution within these islands. Interestingly, we found that these islands were enriched for genes related to female meiosis and metabolism. The islands of high differentiation and divergence were also characterized by higher levels of linkage disequilibrium than the rest of the genome in both species indicating that they might be situated in genomic regions of low recombination. This study provides one of the first insights into genetic basis of hybrid female sterility in organisms with heterogametic females. © 2018 John Wiley & Sons Ltd.

Ultra-Broadband Two-Dimensional Electronic Spectroscopy and Pump-Probe Microscopy of Molecular Systems

Science.gov (United States)

Spokoyny, Boris M.

Ultrafast spectroscopy offers an unprecedented view on the dynamic nature of chemical reactions. From charge transfer in semiconductors to folding and isomerization of proteins, these all important processes can now be monitored and in some instances even controlled on real, physical timescales. One of the biggest challenges of ultrafast science is the incredible energetic complexity of most systems. It is not uncommon to encounter macromolecules or materials with absorption spectra spanning significant portions of the visible spectrum. Monitoring a multitude of electronic and vibrational transitions, all dynamically interacting with each other on femtosecond timescales poses a truly daunting experimental task. The first part of this thesis deals with the development of a novel Two-Dimensional Electronic Spectroscopy (2DES) and its associated, advanced detection methodologies. Owing to its ultra-broadband implementation, this technique enables us to monitor femtosecond chemical dynamics that span the energetic landscape of the entire visible spectrum. In order to demonstrate the utility of our method, we apply it to two laser dye molecules, IR-144 and Cresyl Violet. Variation of photophysical properties on a microscopic scale in either man-made or naturally occurring systems can have profound implications on how we understand their macroscopic properties. Recently, inorganic hybrid perovskites have been tapped as the next generation solar energy harvesting materials. Their remarkable properties include low exciton binding energy, low exciton recombination rates and long carrier diffusion lengths. Nevertheless, considerable variability in device properties made with nearly identical preparation methods has puzzled the community. In the second part of this thesis we use non-linear pump probe microscopy to study the heterogeneous nature of femtosecond carrier dynamics in thin film perovskites. We show that the local morphology of the perovskite thin films has a

Many electron variational ground state of the two dimensional Anderson lattice

International Nuclear Information System (INIS)

Zhou, Y.; Bowen, S.P.; Mancini, J.D.

1991-02-01

A variational upper bound of the ground state energy of two dimensional finite Anderson lattices is determined as a function of lattice size (up to 16 x 16). Two different sets of many-electron basis vectors are used to determine the ground state for all values of the coulomb integral U. This variational scheme has been successfully tested for one dimensional models and should give good estimates in two dimensions

Synergy between electron cyclotron and lower hybrid current drive on Tore Supra

International Nuclear Information System (INIS)

Giruzzi, G.; Artaud, J.F.; Dumont, R.J.; Imbeaux, F.; Bibet, P.; Berger-By, G.; Bouquey, F.; Clary, J.; Darbos, C.; Ekedahl, A.; Hoang, G.T.; Lennholm, M.; Maget, P.; Magne, R.; Segui, J.L.; Bruschi, A.; Granucci, G.

2005-01-01

Improvement (up to a factor ∼ 4) of the electron cyclotron (EC) current drive efficiency in plasmas sustained by lower hybrid (LH) current drive has been demonstrated in stationary conditions on the Tore Supra tokamak. This was made possible by feedback controlled discharges at zero loop voltage, constant plasma current and density. This effect, predicted by kinetic theory, results from a favorable interplay of the velocity space diffusions induced by the two waves: the EC wave pulling low-energy electrons out of the Maxwellian bulk, and the LH wave driving them to high parallel velocities. (author)

Hybrid Threat Center of Gravity Analysis: Cutting the Gordian Knot

Science.gov (United States)

2016-04-04

19b. TELEPHONE NUMBER (Include area code) 04/04/2016 Master’s Thesis 22-7-2015 to 04-04-2016 HYBRID THREAT CENTER OF GRAVITY ANALYSIS: CUTTING THE...CENTER OF GRAVITY ANALYSIS: CUTTING THE GORDIAN KNOT By Michael D. Reilly LtCol, USMC Intentionally left blank...HYBRID THREAT CENTER OF GRAVITY ANALYSIS: CUTTING THE GORDIAN KNOT By Michael D. Reilly LtCol, USMC A paper submitted to the Faculty of the Joint Advanced

Interspecific somatic hybrids between Cyclamen persicum and C. coum, two sexually incompatible species.

Science.gov (United States)

Prange, Anika Nadja Sabine; Bartsch, Melanie; Meiners, Julia; Serek, Margrethe; Winkelmann, Traud

2012-04-01

By applying polyethylene glycol (PEG)-mediated protoplast fusion, the first somatic hybrids were obtained between Cyclamen persicum (2n = 2x = 48) and C. coum (2n = 2x = 30)-two species that cannot be combined by cross breeding. Heterofusion was detected by double fluorescent staining with fluorescein diacetate and scopoletin. The highest heterofusion frequencies (of about 5%) resulted from a protocol using a protoplast density of 1 × 10(6)/mL and 40% PEG. The DNA content of C. coum was estimated for the first time by propidium iodide staining to be 14.7 pg/2C and was 4.6 times higher than that of C. persicum. Among 200 in vitro plantlets regenerated from fusion experiments, most resembled the C. coum parent, whereas only 5 plants showed typical C. persicum phenotypes and 46 had a deviating morphology. By flow cytometry, six putative somatic hybrids were identified. A species-specific DNA marker was developed based on the sequence of the 5.8S gene in the ribosomal nuclear DNA and its flanking internal transcribed spacers ITS1 and ITS2. The hybrid status of only one plant could be verified by the species-specific DNA marker as well as sequencing of the amplification product. RAPD markers turned out to be less informative and applicable for hybrid identification, as no clear additivity of the parental marker bands was observed. Chromosome counting in root tips of four hybrids revealed the presence of the 30 C. coum chromosomes and 2-41 additional ones indicating elimination of C. persicum chromosomes. © Springer-Verlag 2011

Genetic basis of aboveground productivity in two native Populus species and their hybrids.

Science.gov (United States)

Lojewski, Nathan R; Fischer, Dylan G; Bailey, Joseph K; Schweitzer, Jennifer A; Whitham, Thomas G; Hart, Stephen C

2009-09-01

Demonstration of genetic control over riparian tree productivity has major implications for responses of riparian systems to shifting environmental conditions and effects of genetics on ecosystems in general. We used field studies and common gardens, applying both molecular and quantitative techniques, to compare plot-level tree aboveground net primary productivity (ANPP(tree)) and individual tree growth rate constants in relation to plant genetic identity in two naturally occurring Populus tree species and their hybrids. In field comparisons of four cross types (Populus fremontii S. Wats., Populus angustifolia James, F(1) hybrids and backcross hybrids) across 11 natural stands, productivity was greatest for P. fremontii trees, followed by hybrids and lowest in P. angustifolia. A similar pattern was observed in four common gardens across a 290 m elevation and 100 km environmental gradient. Despite a doubling in productivity across the common gardens, the relative differences among the cross types remained constant. Using clonal replicates in a common garden, we found ANPP(tree) to be a heritable plant trait (i.e., broad-sense heritability), such that plant genetic factors explained between 38% and 82% of the variation in ANPP(tree). Furthermore, analysis of the genetic composition among individual tree genotypes using restriction fragment length polymorphism molecular markers showed that genetically similar trees also exhibited similar ANPP(tree). These findings indicate strong genetic contributions to natural variation in ANPP with important ecological implications.

Potential Formation in Front of an Electron Emitting Electrode in a Two-Electron Temperature Plasma

International Nuclear Information System (INIS)

Gyergyek, T.; Cercek, M.; Erzen, D.

2003-01-01

Plasma potential formation in the pre-sheath region of a floating electron emitting electrode (collector) is studied theoretically in a two-electron-temperature plasma using a static kinetic plasma-sheath model. Dependence of the collector floating potential, the plasma potential in the pre-sheath region, and the critical emission coefficient on the hot electron density and temperature is calculated. It is found that for high hot to cool electron temperature ratio a double layer like solutions exist in a certain range of hot to cool electron densities

Two-point model for electron transport in EBT

International Nuclear Information System (INIS)

Chiu, S.C.; Guest, G.E.

1980-01-01

The electron transport in EBT is simulated by a two-point model corresponding to the central plasma and the edge. The central plasma is assumed to obey neoclassical collisionless transport. The edge plasma is assumed turbulent and modeled by Bohm diffusion. The steady-state temperatures and densities in both regions are obtained as functions of neutral influx and microwave power. It is found that as the neutral influx decreases and power increases, the edge density decreases while the core density increases. We conclude that if ring instability is responsible for the T-M mode transition, and if stability is correlated with cold electron density at the edge, it will depend sensitively on ambient gas pressure and microwave power

Strong-field ionization of xenon dimers: The effect of two-equivalent-center interference and of driving ionic transitions

Science.gov (United States)

Zhang, C.; Feng, T.; Raabe, N.; Rottke, H.

2018-02-01

Strong-field ionization (SFI) of the homonuclear noble gas dimer Xe2 is investigated and compared with SFI of the Xe atom and of the ArXe heteronuclear dimer by using ultrashort Ti:sapphire laser pulses and photoelectron momentum spectroscopy. The large separation of the two nuclei of the dimer allows the study of two-equivalent-center interference effects on the photoelectron momentum distribution. Comparing the experimental results with a new model calculation, which is based on the strong-field approximation, actually reveals the influence of interference. Moreover, the comparison indicates that the presence of closely spaced gerade and ungerade electronic state pairs of the Xe2 + ion at the Xe2 ionization threshold, which are strongly dipole coupled, affects the photoelectron momentum distribution.

No-Disjunction and loss of anafasica Hamster-human hybrid embryos of two cells

International Nuclear Information System (INIS)

Ponsa, I.; Tusell, L.; Alvarez, R.; Genesca, A.; Miro, R.; Egozcue, J.

1998-01-01

To investigate the possible effect anafasica the ionizing radiations in masculine germinal cells a new test it has been developed combining two techniques, the fecundation interspecific gives ovocitos hamster without area pellucid with human sperms and the fluorescent in situ hybridization in cells in interface using probes gives DNA specific centrometricas. Analyzing the segregation gives the chromosomes marked in the embryos two cells, you can detect the reciprocal products easily an anomalous segregation. Give this way the recount the fluorescent signs in the nuclei siblings and in the micronucleus it provides an esteem the due aneuploidy to errors meiotic or premiotic, with this way the resulting aneuploidy the errors in the first division mitotic the embryos, as much no-disjunction as lost anafasica

Multiplexed interfacial transduction of nucleic acid hybridization using a single color of immobilized quantum dot donor and two acceptors in fluorescence resonance energy transfer.

Science.gov (United States)

Algar, W Russ; Krull, Ulrich J

2010-01-01

A multiplexed solid-phase assay for the detection of nucleic acid hybridization was developed on the basis of a single color of immobilized CdSe/ZnS quantum dot (QD) as a donor in fluorescence resonance energy transfer (FRET). This work demonstrated that two channels of detection did not necessitate two different QD donors. Two probe oligonucleotides were coimmobilized on optical fibers modified with QDs, and a sandwich assay was used to associate the acceptor dyes with interfacial hybridization events without target labeling. FRET-sensitized acceptor emission provided an analytical signal that was concentration dependent down to 10 nM. Changes in the ratio of coimmobilized probe oligonucleotides were found to yield linear changes in the relative amounts of acceptor emission. These changes were compared to previous studies that used mixed films of two QD donors for two detection channels. The analysis indicated that probe dilution effects were primarily driven by changes in acceptor number density and that QD dilution effects or changes in mean donor-acceptor distance were secondary. Hybridization kinetics were found to be consistent between different ratios of coimmobilized probes, suggesting that hybridization in this type of system occurred via the accepted model for solid-phase hybridization, where adsorption and then diffusion at the solid interface drove hybridization.

Universal logic gates via liquid-electronic hybrid divider

KAUST Repository

Zhou, Bingpu

2012-01-01

We demonstrated two-input microdroplet-based universal logic gates using a liquid-electronic hybrid divider. All 16 Boolean logic functions have been realized by manipulating the applied voltages. The novel platform consists of a microfluidic chip with integrated microdroplet detectors and external electronic components. The microdroplet detectors act as the communication media for fluidic and electronic information exchange. The presence or absence of microdroplets at the detector translates into the binary signal 1 or 0. The embedded micro-mechanical pneumatically actuated valve (PAV), fabricated using the well-developed multilayer soft lithography technique, offers biocompatibility, flexibility and accuracy for the on-chip realization of different logic functions. The microfluidic chip can be scaled up to construct large-scale microfluidic logic computation. On the other hand, the microfluidic chip with a specific logic function can be applied to droplet-based chemical reactions for on-demand bio or chemical analysis. Our experimental results have presented an autonomously driven, precision-controlled microfluidic chip for chemical reactions based on the IF logic function. © 2012 The Royal Society of Chemistry.

Strongly anisotropic spin-orbit splitting in a two-dimensional electron gas

DEFF Research Database (Denmark)

Michiardi, Matteo; Bianchi, Marco; Dendzik, Maciej

2015-01-01

Near-surface two-dimensional electron gases on the topological insulator Bi$_2$Te$_2$Se are induced by electron doping and studied by angle-resolved photoemission spectroscopy. A pronounced spin-orbit splitting is observed for these states. The $k$-dependent splitting is strongly anisotropic to a...

Analysis of differentially expressed genes in two immunologically distinct strains of Eimeria maxima using suppression subtractive hybridization and dot-blot hybridization

Science.gov (United States)

2014-01-01

Background It is well known that different Eimeria maxima strains exhibit significant antigenic variation. However, the genetic basis of these phenotypes remains unclear. Methods Total RNA and mRNA were isolated from unsporulated oocysts of E. maxima strains SH and NT, which were found to have significant differences in immunogenicity in our previous research. Two subtractive cDNA libraries were constructed using suppression subtractive hybridization (SSH) and specific genes were further analyzed by dot-blot hybridization and qRT-PCR analysis. Results A total of 561 clones were selected from both cDNA libraries and the length of the inserted fragments was 0.25–1.0 kb. Dot-blot hybridization revealed a total of 86 differentially expressed clones (63 from strain SH and 23 from strain NT). Nucleotide sequencing analysis of these clones revealed ten specific contigs (six from strain SH and four from strain NT). Further analysis found that six contigs from strain SH and three from strain NT shared significant identities with previously reported proteins, and one contig was presumed to be novel. The specific differentially expressed genes were finally verified by RT-PCR and qRT-PCR analyses. Conclusions The data presented here suggest that specific genes identified between the two strains may be important molecules in the immunogenicity of E. maxima that may present potential new drug targets or vaccine candidates for coccidiosis. PMID:24894832

Chlorosis caused by two recessively interacting genes reveals a role of RNA helicase in hybrid breakdown in Arabidopsis thaliana.

Science.gov (United States)

Plötner, Björn; Nurmi, Markus; Fischer, Axel; Watanabe, Mutsumi; Schneeberger, Korbinian; Holm, Svante; Vaid, Neha; Schöttler, Mark Aurel; Walther, Dirk; Hoefgen, Rainer; Weigel, Detlef; Laitinen, Roosa A E

2017-07-01

Hybrids often differ in fitness from their parents. They may be superior, translating into hybrid vigour or heterosis, but they may also be markedly inferior, because of hybrid weakness or incompatibility. The underlying genetic causes for the latter can often be traced back to genes that evolve rapidly because of sexual or host-pathogen conflicts. Hybrid weakness may manifest itself only in later generations, in a phenomenon called hybrid breakdown. We have characterized a case of hybrid breakdown among two Arabidopsis thaliana accessions, Shahdara (Sha, Tajikistan) and Lövvik-5 (Lov-5, Northern Sweden). In addition to chlorosis, a fraction of the F 2 plants have defects in leaf and embryo development, and reduced photosynthetic efficiency. Hybrid chlorosis is due to two major-effect loci, of which one, originating from Lov-5, appears to encode an RNA helicase (AtRH18). To examine the role of the chlorosis allele in the Lövvik area, in addition to eight accessions collected in 2009, we collected another 240 accessions from 15 collections sites, including Lövvik, from Northern Sweden in 2015. Genotyping revealed that Lövvik collection site is separated from the rest. Crosses between 109 accessions from this area and Sha revealed 85 cases of hybrid chlorosis, indicating that the chlorosis-causing allele is common in this area. These results suggest that hybrid breakdown alleles not only occur at rapidly evolving loci, but also at genes that code for conserved processes. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

AFM Imaging of Hybridization Chain Reaction-Mediated Signal Transmission Between two DNA Origami Structures

DEFF Research Database (Denmark)

Helmig, Sarah Wendelbo; Gothelf, Kurt Vesterager

2017-01-01

transfer between two connected DNA nanostructures, using the hybridization chain reaction (HCR). Two sets of metastable DNA hairpins - of which one is immobilized in specific points along tracks on DNA origami structures - are polymerized to form a continuous DNA duplex, which is visible using atomic force...... microscopy (AFM). Upon addition of a designed initiator, the initiation signal is efficiently transferred >200 nm from a specific location on one origami structure to an end point on another origami structure. The system shows no significant loss of signal when crossing from one nanostructure to another...

Fluorescence in situ hybridization karyotyping reveals the presence of two distinct genomes in the taxon Aegilops tauschii

OpenAIRE

Zhao, Laibin; Ning, Shunzong; Yi, Yingjin; Zhang, Lianquan; Yuan, Zhongwei; Wang, Jirui; Zheng, Youliang; Hao, Ming; Liu, Dengcai

2018-01-01

Background Aegilops tauschii is the donor of the bread wheat D genome. Based on spike morphology, the taxon has conventionally been subdivided into ssp. tauschii and ssp. strangulata. The present study was intended to address the poor match between this whole plant morphology-based subdivision and genetic relationships inferred from genotyping by fluorescence in situ hybridization karyotyping a set of 31 Ae. tauschii accessions. Results The distribution of sites hybridizing to the two probes ...

Theoretical description of high-lying two-electrons states

International Nuclear Information System (INIS)

Greene, C.H.; Cavagnero, M.; Sadeghpour, H.R.

1993-01-01

Within the past two years, experiments on high-lying doubly-excited states in He and H- have shown spectra at energies near excited hydrogenic thresholds having principal quantum numbers in the range N=5--9. While they display some nontrivial complexities, the spectra are tremendously simpler than might be anticipated on the basis of independent electron models, in that only a small fraction of the total number of anticipated resonances are observed experimentally. Moreover, for principal quantum number N that are not too high, specifically N - , the resonance positions are described accurately by adiabatic calculations using hyperspherical coordinates and can be parametrized by a remarkably simple two-electron Rydberg formula. The observed propensity for excitation of only a small subset of the possible resonance states has been codified by several groups into approximate selection rules based on alternative (but apparently equivalent) classification schemes. Comparatively few attempts have been made at quantitative tests of the validity of these rules. The present review describes recent efforts to quantify their accuracy and limitations using R-matrix and quantum defect techniques, and Smith's delay-time matrix. Prospensity rules for exciting different degrees of freedom are found to differ greatly in their degree of validity

Auroral electron acceleration by lower-hybrid waves

International Nuclear Information System (INIS)

Bingham, R.; Bryant, D.A.; Hall, D.S.

1986-01-01

Because the particles and electric fields association with inverted-V electron streams do not have the characteristics expected for acceleration by a quasistatic potential difference, the possiblity that the electrons are stochastically accelerated by waves is investigated. It is demonstrated that the lower hybrid waves seen on auroral field lines have the righ properties to account for the electron acceleration. It is further shown that the lower hybrid wave power measured on auroral field lines can be generated by the streaming ions observed at the boundary of the plasma sheet, and that this wave power is sufficient to account for the electron power observed close to the atmosphere. (author)

Two-photon exchange in elastic electron-nucleon scattering

International Nuclear Information System (INIS)

Blunden, P.G.; Melnitchouk, W.; Tjon, J.A.

2005-01-01

A detailed study of two-photon exchange in unpolarized and polarized elastic electron-nucleon scattering is presented, taking particular account of nucleon finite size effects. Contributions from nucleon elastic intermediate states are found to have a strong angular dependence, which leads to a partial resolution of the discrepancy between the Rosenbluth and polarization transfer measurements of the proton electric to magnetic form factor ratio, G E /G M . The two-photon exchange contribution to the longitudinal polarization transfer P L is small, whereas the contribution to the transverse polarization transfer P T is enhanced at backward angles by several percent, increasing with Q 2 . This gives rise to a small, E /G M obtained from the polarization transfer ratio P T /P L at large Q 2 . We also compare the two-photon exchange effects with data on the ratio of e + p to e - p cross sections, which is predicted to be enhanced at backward angles. Finally, we evaluate the corrections to the form factors of the neutron and estimate the elastic intermediate state contribution to the 3 He form factors

Hybrid sterility in crosses between two Brazilian sibling species of the Anopheles albitarsis complex.

Science.gov (United States)

Fontoura, Nathalia Giglio; Araki, Alejandra Saori; Van Der Maas Azevedo, Renata; Galardo, Allan Kardec Ribeiro; Peixoto, Alexandre Afranio; Lima, José Bento Pereira

2014-12-04

Complexes of cryptic species are common in several taxa and this is also the case in the Anopheles genus, a group including all known human malaria vectors. The Anopheles albitarsis complex comprises at least nine cryptic species, some of which are implicated as vectors of human malaria. Several different types of data have been generated for this species complex such as cytogenetics, alloenzymes, morphological and feeding behavioral, hybridization experiments, RAPD-PCR and RFLP and mitochondrial and nuclear markers. Studies focused on its postzygotic isolation are still somewhat rare in the literature despite their importance to understand the speciation process and the level of gene flow potentially occurring among the different sibling species. Hybridization experiments between Anopheles albitarsis s.s. and Anopheles marajoara, as well as backcrosses between hybrids and Anopheles albitarsis s.s., were performed using the induced mating technique. Results were compared to intraspecific crosses. Larva-to-adult viability and sex ratio were also assessed. Male hybrids show very low insemination rates and nearly complete sterility, apparently due to abnormalities in their reproductive organs. Evidence of partial sterility among the hybrid females was also observed. Our data indicated that Anopheles albitarsis s.s. and Anopheles marajoara show a high level of postzygotic isolation with a strong hybrid male sterility. This result is consistent with the Haldane's rule which states that in interspecific crosses the heterogametic sex is the first to be affected. However, the fact that the females are not completely sterile raises the possibility of introgression between these two siblings species.

Two-loop controller for maximizing performance of a grid-connected photovoltaic - fuel cell hybrid power plant

Science.gov (United States)

Ro, Kyoungsoo

The study started with the requirement that a photovoltaic (PV) power source should be integrated with other supplementary power sources whether it operates in a stand-alone or grid-connected mode. First, fuel cells for a backup of varying PV power were compared in detail with batteries and were found to have more operational benefits. Next, maximizing performance of a grid-connected PV-fuel cell hybrid system by use of a two-loop controller was discussed. One loop is a neural network controller for maximum power point tracking, which extracts maximum available solar power from PV arrays under varying conditions of insolation, temperature, and system load. A real/reactive power controller (RRPC) is the other loop. The RRPC meets the system's requirement for real and reactive powers by controlling incoming fuel to fuel cell stacks as well as switching control signals to a power conditioning subsystem. The RRPC is able to achieve more versatile control of real/reactive powers than the conventional power sources since the hybrid power plant does not contain any rotating mass. Results of time-domain simulations prove not only effectiveness of the proposed computer models of the two-loop controller, but also their applicability for use in transient stability analysis of the hybrid power plant. Finally, environmental evaluation of the proposed hybrid plant was made in terms of plant's land requirement and lifetime COsb2 emissions, and then compared with that of the conventional fossil-fuel power generating forms.

Comparing two iteration algorithms of Broyden electron density mixing through an atomic electronic structure computation

International Nuclear Information System (INIS)

Zhang Man-Hong

2016-01-01

By performing the electronic structure computation of a Si atom, we compare two iteration algorithms of Broyden electron density mixing in the literature. One was proposed by Johnson and implemented in the well-known VASP code. The other was given by Eyert. We solve the Kohn-Sham equation by using a conventional outward/inward integration of the differential equation and then connect two parts of solutions at the classical turning points, which is different from the method of the matrix eigenvalue solution as used in the VASP code. Compared to Johnson’s algorithm, the one proposed by Eyert needs fewer total iteration numbers. (paper)

Genomic change, retrotransposon mobilization and extensive cytosine methylation alteration in Brassica napus introgressions from two intertribal hybridizations.

Directory of Open Access Journals (Sweden)

Xueli Zhang

Full Text Available Hybridization and introgression represent important means for the transfer and/or de novo origination of traits and play an important role in facilitating speciation and plant breeding. Two sets of introgression lines in Brassica napus L. were previously established by its intertribal hybridizations with two wild species and long-term selection. In this study, the methods of amplified fragment length polymorphisms (AFLP, sequence-specific amplification polymorphism (SSAP and methylation-sensitive amplified polymorphism (MSAP were used to determine their genomic change, retrotransposon mobilization and cytosine methylation alteration in these lines. The genomic change revealed by the loss or gain of AFLP bands occurred for ∼10% of the total bands amplified in the two sets of introgressions, while no bands specific for wild species were detected. The new and absent SSAP bands appeared for 9 out of 11 retrotransposons analyzed, with low frequency of new bands and their total percentage of about 5% in both sets. MSAP analysis indicated that methylation changes were common in these lines (33.4-39.8% and the hypermethylation was more frequent than hypomethylation. Our results suggested that certain extents of genetic and epigenetic alterations were induced by hybridization and alien DNA introgression. The cryptic mechanism of these changes and potential application of these lines in breeding were also discussed.

Hybrid synchronization of two independent chaotic systems on ...

Indian Academy of Sciences (India)

One is how the same network node of the complex network was affected by different information sources. Another is how to achieve hybrid synchronization on the network. In this paper, the theoretical analysis andnumerical simulation on various complex networks are implemented. The results indicate that the hybrid ...

Hybrid electronic/optical synchronized chaos communication system.

Science.gov (United States)

Toomey, J P; Kane, D M; Davidović, A; Huntington, E H

2009-04-27

A hybrid electronic/optical system for synchronizing a chaotic receiver to a chaotic transmitter has been demonstrated. The chaotic signal is generated electronically and injected, in addition to a constant bias current, to a semiconductor laser to produce an optical carrier for transmission. The optical chaotic carrier is photodetected to regenerate an electronic signal for synchronization in a matched electronic receiver The system has been successfully used for the transmission and recovery of a chaos masked message that is added to the chaotic optical carrier. Past demonstrations of synchronized chaos based, secure communication systems have used either an electronic chaotic carrier or an optical chaotic carrier (such as the chaotic output of various nonlinear laser systems). This is the first electronic/optical hybrid system to be demonstrated. We call this generation of a chaotic optical carrier by electronic injection.

Decentralised treatment of concentrated sewage at low temperature in a two-step anaerobic system: two upflow-hybrid septic tanks.

Science.gov (United States)

Elmitwalli, T A; Sayed, S; Groendijk, L; van Lier, J; Zeeman, G; Lettinga, G

2003-01-01

The decentralised treatment of concentrated sewage (about 3,600 mgCOD/l) at low temperature was investigated in a two-step anaerobic system: two-anaerobic hybrid (AH) septic tanks (each 0.575 m3). The two reactors were placed in a temperature controlled-room and the HRT was 2.5 days for each reactor. The system was fed with concentrated domestic sewage, mainly black water from about 40 toilets flushed with only 4 litre of water and a limited amount of grey water. The system showed high removal efficiency for the different COD fractions. Mean removal efficiencies in the two-step AH-septic tank at 5 days HRT and 13 degrees C were 94, 98, 74 and 78% for total COD, suspended COD, colloidal COD and dissolved COD respectively. The results of short run experiments indicated that the presence of reticulated polyurethane foam (RPF) media in the AH-septic tank improved the removal of suspended COD by 22%. The first AH-septic tank was full of sludge after 4 months of operation due to the high removal of particulate COD and the limited hydrolysis at low temperature conditions. Therefore, a simple mathematical model was developed based on ADM1 (the IWA model in 2002). Based on the experimental results and the mathematical model, only a one-step AH septic tank is required. An HRT of 5.5-7.5 days is needed for that one-step AH septic tank to treat concentrated sewage at a low temperature of 13 degrees C. Such a system can provide a total COD removal as high as 87% and will be full of sludge after a period of more than a year.

Development of two electronic bladder diaries: a patient and healthcare professionals pilot study.

Science.gov (United States)

Mangera, Altaf; Marzo, Alberto; Heron, Nicola; Fernando, Dayan; Hameed, Khawar; Soliman, Abdel-Hamid A; Bradley, Mike; Hosking, Ian; Abdel-Maguid, Mohamed; Levermore, Martin; Tindale, Wendy B; Chapple, Christopher

2014-09-01

Assess patients' preferences in a pilot crossover study of two different electronic voiding diaries against a standard paper diary. Assess urological health professional (HP) opinions on the electronic bladder diary reporting system. Two different electronic diaries were developed: (1) electronically read diary-a card with predefined slots read by a card reader and (2) e-diary-a handheld touch screen device. Data uploaded from either electronic diary produced an electronic report. We recruited 22 patients split into two cohorts for each electronic diary, 11 completed each type of electronic diary for 3 days either preceded or followed by a standard paper diary for 3 days. Both diaries were completed on the 7th day. Patients' perceptions of both diaries were recorded using a standardized questionnaire. A HP study recruited 22 urologists who were given the paper diary and the electronic reports. Time taken for analysis was recorded along with accuracy and HP preferences. The majority of patients (82%) preferred the e-diary and only 1/11 found it difficult to use. Patients had the same preference for the electronically read diary as the paper diary. The paper diary took 66% longer to analyze than the electronic report (P analyzed with an accuracy of 58% compared to 100%. Slightly more HP (9%) preferred the electronic report to the paper diary. This proposed e-diary with its intuitive interface has overcome previous deficiencies in electronic diaries with most patients finding the format user-friendly. Electronic reports make analysis and interpretation by HP quicker and more accurate. © 2013 Wiley Periodicals, Inc.

Reciprocal Genetics: Identifying QTL for General and Specific Combining Abilities in Hybrids Between Multiparental Populations from Two Maize (Zea mays L.) Heterotic Groups.

Science.gov (United States)

Giraud, Héloïse; Bauland, Cyril; Falque, Matthieu; Madur, Delphine; Combes, Valérie; Jamin, Philippe; Monteil, Cécile; Laborde, Jacques; Palaffre, Carine; Gaillard, Antoine; Blanchard, Philippe; Charcosset, Alain; Moreau, Laurence

2017-11-01

Several plant and animal species of agricultural importance are commercialized as hybrids to take advantage of the heterosis phenomenon. Understanding the genetic architecture of hybrid performances is therefore of key importance. We developed two multiparental maize ( Zea mays L.) populations, each corresponding to an important heterotic group (dent or flint) and comprised of six connected biparental segregating populations of inbred lines (802 and 822 lines for each group, respectively) issued from four founder lines. Instead of using "testers" to evaluate their hybrid values, segregating lines were crossed according to an incomplete factorial design to produce 951 dent-flint hybrids, evaluated for four biomass production traits in eight environments. QTL detection was carried out for the general-combining-ability (GCA) and specific-combining-ability (SCA) components of hybrid value, considering allelic effects transmitted from each founder line. In total, 42 QTL were detected across traits. We detected mostly QTL affecting GCA, 31% (41% for dry matter yield) of which also had mild effects on SCA. The small impact of dominant effects is consistent with the known differentiation between the dent and flint heterotic groups and the small percentage of hybrid variance due to SCA observed in our design (∼20% for the different traits). Furthermore, most (80%) of GCA QTL were segregating in only one of the two heterotic groups. Relative to tester-based designs, use of hybrids between two multiparental populations appears highly cost efficient to detect QTL in two heterotic groups simultaneously. This presents new prospects for selecting superior hybrid combinations with markers. Copyright © 2017 by the Genetics Society of America.

The hybrid two stage anticlockwise cycle for ecological energy conversion

Directory of Open Access Journals (Sweden)

Cyklis Piotr

2016-01-01

Full Text Available The anticlockwise cycle is commonly used for refrigeration, air conditioning and heat pumps applications. The application of refrigerant in the compression cycle is within the temperature limits of the triple point and the critical point. New refrigerants such as 1234yf or 1234ze have many disadvantages, therefore natural refrigerants application is favourable. The carbon dioxide and water can be applied only in the hybrid two stages cycle. The possibilities of this solutions are shown for refrigerating applications, as well some experimental results of the adsorption-compression double stages cycle, powered with solar collectors are shown. As a high temperature cycle the adsorption system is applied. The low temperature cycle is the compression stage with carbon dioxide as a working fluid. This allows to achieve relatively high COP for low temperature cycle and for the whole system.

Formation of presheath and current-free double layer in a two-electron-temperature plasma

International Nuclear Information System (INIS)

Sato, Kunihiro; Miyawaki, Fujio

1992-02-01

Development of the steady-state potential in a two-temperature-electron plasma in contact with the wall is investigated analytically. It is shown that if the hot- to cold electron temperature ratio is greater than ten, the potential drop in the presheath, which is allowed to have either a small value characterized by the cold electrons or a large value by the hot electrons, discontinuously changes at a critical value for the hot- to total electron density ratio. It is also found that the monotonically decreasing potential structure which consists of the first presheath, a current-free double layer, the second presheath, and the sheath can be steadily formed in a lower range of the hot- to total electron density ratio around the critical value. The current-free double layer is set up due to existence of the two electron species and cold ions generated by ionization so as to connect two presheath potentials at different levels. (author)

A Two-stage DC-DC Converter for the Fuel Cell-Supercapacitor Hybrid System

DEFF Research Database (Denmark)

Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.

2009-01-01

A wide input range multi-stage converter is proposed with the fuel cells and supercapacitors as a hybrid system. The front-end two-phase boost converter is used to optimize the output power and to reduce the current ripple of fuel cells. The supercapacitor power module is connected by push...... and designed. A 1kW prototype controlled by TMS320F2808 DSP is built in the lab. Simulation and experimental results confirm the feasibility of the proposed two stage dc-dc converter system.......-pull-forward half bridge (PPFHB) converter with coupled inductors in the second stage to handle the slow transient response of the fuel cells and realize the bidirectional power flow control. Moreover, this cascaded structure simplifies the power management. The control strategy for the whole system is analyzed...

Electron surfing acceleration by the electron two-stream instability in a weak magnetic field

International Nuclear Information System (INIS)

Dieckmann, M E; Shukla, P K

2006-01-01

The thermalization of relativistically flowing colliding plasmas is not well understood. The transition layer, in which both plasmas interact and thermalize, is wide and highly structured and the instabilities in this layer may yield non-thermal particle distributions and shock-less energy dissipation. The objective in this work is to explore the ability of an electron two-stream instability for thermalizing a plasma beam that moves at the mildly relativistic speed 0.3c through weakly magnetized plasma and to identify the resulting particle distributions. It is demonstrated here with particle-in-cell simulations that the electron two-stream instability leads to waves that propagate within a wide angular range relative to the flow velocity. The waves are thus not planar, as required for efficient electron surfing acceleration (ESA). The short lifetime of the waves implies, however, only weak modifications of the ESA by the oblique modes, since the waves are sufficiently homogeneous. The ion (proton) beams are not modulated, which would be required to extract some of their energy. The instability can thus heat the electrons significantly, but it fails to accelerate them to relativistic energies and it cannot form a shock layer by thermalizing the protons, at least not for the system and the resolved timescales considered here

Electron surfing acceleration by the electron two-stream instability in a weak magnetic field

Energy Technology Data Exchange (ETDEWEB)

Dieckmann, M E; Shukla, P K [Institut fuer Theoretische Physik IV, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

2006-10-15

The thermalization of relativistically flowing colliding plasmas is not well understood. The transition layer, in which both plasmas interact and thermalize, is wide and highly structured and the instabilities in this layer may yield non-thermal particle distributions and shock-less energy dissipation. The objective in this work is to explore the ability of an electron two-stream instability for thermalizing a plasma beam that moves at the mildly relativistic speed 0.3c through weakly magnetized plasma and to identify the resulting particle distributions. It is demonstrated here with particle-in-cell simulations that the electron two-stream instability leads to waves that propagate within a wide angular range relative to the flow velocity. The waves are thus not planar, as required for efficient electron surfing acceleration (ESA). The short lifetime of the waves implies, however, only weak modifications of the ESA by the oblique modes, since the waves are sufficiently homogeneous. The ion (proton) beams are not modulated, which would be required to extract some of their energy. The instability can thus heat the electrons significantly, but it fails to accelerate them to relativistic energies and it cannot form a shock layer by thermalizing the protons, at least not for the system and the resolved timescales considered here.

Two dimensional electron systems for solid state quantum computation

Science.gov (United States)

Mondal, Sumit

Two dimensional electron systems based on GaAs/AlGaAs heterostructures are extremely useful in various scientific investigations of recent times including the search for quantum computational schemes. Although significant strides have been made over the past few years to realize solid state qubits on GaAs/AlGaAs 2DEGs, there are numerous factors limiting the progress. We attempt to identify factors that have material and design-specific origin and develop ways to overcome them. The thesis is divided in two broad segments. In the first segment we describe the realization of a new field-effect induced two dimensional electron system on GaAs/AlGaAs heterostructure where the novel device-design is expected to suppress the level of charge noise present in the device. Modulation-doped GaAs/AlGaAs heterostructures are utilized extensively in the study of quantum transport in nanostructures, but charge fluctuations associated with remote ionized dopants often produce deleterious effects. Electric field-induced carrier systems offer an attractive alternative if certain challenges can be overcome. We demonstrate a field-effect transistor in which the active channel is locally devoid of modulation-doping, but silicon dopant atoms are retained in the ohmic contact region to facilitate low-resistance contacts. A high quality two-dimensional electron gas is induced by a field-effect that is tunable over a density range of 6.5x10 10cm-2 to 2.6x1011cm-2 . Device design, fabrication, and low temperature (T=0.3K) characterization results are discussed. The demonstrated device-design overcomes several existing limitations in the fabrication of field-induced 2DEGs and might find utility in hosting nanostructures required for making spin qubits. The second broad segment describes our effort to correlate transport parameters measured at T=0.3K to the strength of the fractional quantum Hall state observed at nu=5/2 in the second Landau level of high-mobility GaAs/AlGaAs two dimensional

Monitoring of beer fermentation based on hybrid electronic tongue.

Science.gov (United States)

Kutyła-Olesiuk, Anna; Zaborowski, Michał; Prokaryn, Piotr; Ciosek, Patrycja

2012-10-01

Monitoring of biotechnological processes, including fermentation is extremely important because of the rapidly occurring changes in the composition of the samples during the production. In the case of beer, the analysis of physicochemical parameters allows for the determination of the stage of fermentation process and the control of its possible perturbations. As a tool to control the beer production process a sensor array can be used, composed of potentiometric and voltammetric sensors (so-called hybrid Electronic Tongue, h-ET). The aim of this study is to apply electronic tongue system to distinguish samples obtained during alcoholic fermentation. The samples originate from batch of homemade beer fermentation and from two stages of the process: fermentation reaction and maturation of beer. The applied sensor array consists of 10 miniaturized ion-selective electrodes (potentiometric ET) and silicon based 3-electrode voltammetric transducers (voltammetric ET). The obtained results were processed using Partial Least Squares (PLS) and Partial Least Squares-Discriminant Analysis (PLS-DA). For potentiometric data, voltammetric data, and combined potentiometric and voltammetric data, comparison of the classification ability was conducted based on Root Mean Squared Error (RMSE), sensitivity, specificity, and coefficient F calculation. It is shown, that in the contrast to the separately used techniques, the developed hybrid system allowed for a better characterization of the beer samples. Data fusion in hybrid ET enables to obtain better results both in qualitative analysis (RMSE, specificity, sensitivity) and in quantitative analysis (RMSE, R(2), a, b). Copyright © 2012 Elsevier B.V. All rights reserved.

Hall Conductivity in a Quasi-Two-Dimensional Disordered Electron System

Institute of Scientific and Technical Information of China (English)

YANG Yong-Hong; WANG Yong-Gang; LIU Mei

2002-01-01

By making use of the diagrammatic techniques in perturbation theory,we have investigated the Hall effect in a quasi-two-dimensional disordered electron system.In the weakly localized regime,the analytical expression for quantum correction to Hall conductivity has been obtained using the Kubo formalism and quasiclassical approximation.The relevant dimensional crossover behavior from three dimensions to two dimensions with decreasing the interlayer hopping energy is discussed.The quantum interference effect is shown to have a vanishing correction t,o the Hall coefficient.

Strong-coupling behaviour of two t - J chains with interchain single-electron hopping

International Nuclear Information System (INIS)

Zhang Guangming; Feng Shiping; Yu Lu.

1994-01-01

Using the fermion-spin transformation to implement spin-charge separation of constrained electrons, a model of two t - J chains with interchain single-electron hopping is studied by abelian bosonization. After spin-charge decoupling the charge dynamics can be trivially solved, while the spin dynamics is determined by a strong-coupling fixed point where the correlation functions can be calculated explicitly. This is a generalization of the Luther-Emery line for two-coupled t - J chains. The interchain single-electron hopping changes the asymptotic behaviour of the interchain spin-spin correlation functions and the electron Green function, but their exponents are independent of the coupling strength. (author). 25 refs

Pressure dependence of electron density distribution and d-p-π hybridization in titanate perovskite ferroelectrics

Science.gov (United States)

Yamanaka, Takamitsu; Nakamoto, Yuki; Ahart, Muhtar; Mao, Ho-kwang

2018-04-01

Electron density distributions of PbTi O3 , BaTi O3 , and SrTi O3 were determined by synchrotron x-ray powder diffraction up to 55 GPa at 300 K and ab initio quantum chemical molecular orbital (MO) calculations, together with a combination of maximum entropy method calculations. The intensity profiles of Bragg peaks reveal split atoms in both ferroelectric PbTi O3 and BaTi O3 , reflecting the two possible positions occupied by the Ti atom. The experimentally obtained atomic structure factor was used for the determination of the deformation in electron density and the d-p-π hybridization between dx z (and dy z) of Ti and px (and py) of O in the Ti-O bond. Ab initio MO calculations proved the change of the molecular orbital coupling and of Mulliken charges with a structure transformation. The Mulliken charge of Ti in the Ti O6 octahedron increased in the ionicity with increasing pressure in the cubic phase. The bonding nature is changed with a decrease in the hybridization of the Ti-O bond and the localization of the electron density with increasing pressure. The hybridization decreases with pressure and disappears in the cubic paraelectric phase, which has a much more localized electron density distribution.

Two color interferometric electron density measurement in an axially blown arc

Science.gov (United States)

Stoller, Patrick; Carstensen, Jan; Galletti, Bernardo; Doiron, Charles; Sokolov, Alexey; Salzmann, René; Simon, Sandor; Jabs, Philipp

2016-09-01

High voltage circuit breakers protect the power grid by interrupting the current in case of a short circuit. To do so an arc is ignited between two contacts as they separate; transonic gas flow is used to cool and ultimately extinguish the arc at a current-zero crossing of the alternating current. A detailed understanding of the arc interruption process is needed to improve circuit breaker design. The conductivity of the partially ionized gas remaining after the current-zero crossing, a key parameter in determining whether the arc will be interrupted or not, is a function of the electron density. The electron density, in turn, is a function of the detailed dynamics of the arc cooling process, which does not necessarily occur under local thermodynamic equilibrium (LTE) conditions. In this work, we measure the spatially resolved line-integrated index of refraction in a near-current-zero arc stabilized in an axial flow of synthetic air with two nanosecond pulsed lasers at wavelengths of 532 nm and 671 nm. Generating a stable, cylindrically symmetric arc enables us to determine the three-dimensional index of refraction distribution using Abel inversion. Due to the wavelength dependence of the component of the index of refraction related to the free electrons, the information at two different wavelengths can be used to determine the electron density. This information allows us to determine how important it is to take into account non-equilibrium effects for accurate modeling of the physics of decaying arcs.

Spodoptera frugiperda (Lepidoptera: Noctuidae) host-plant variants: two host strains or two distinct species?

Science.gov (United States)

Dumas, Pascaline; Legeai, Fabrice; Lemaitre, Claire; Scaon, Erwan; Orsucci, Marion; Labadie, Karine; Gimenez, Sylvie; Clamens, Anne-Laure; Henri, Hélène; Vavre, Fabrice; Aury, Jean-Marc; Fournier, Philippe; Kergoat, Gael J; d'Alençon, Emmanuelle

2015-06-01

The moth Spodoptera frugiperda is a well-known pest of crops throughout the Americas, which consists of two strains adapted to different host-plants: the first feeds preferentially on corn, cotton and sorghum whereas the second is more associated with rice and several pasture grasses. Though morphologically indistinguishable, they exhibit differences in their mating behavior, pheromone compositions, and show development variability according to the host-plant. Though the latter suggest that both strains are different species, this issue is still highly controversial because hybrids naturally occur in the wild, not to mention the discrepancies among published results concerning mating success between the two strains. In order to clarify the status of the two host-plant strains of S. frugiperda, we analyze features that possibly reflect the level of post-zygotic isolation: (1) first generation (F1) hybrid lethality and sterility; (2) patterns of meiotic segregation of hybrids in reciprocal second generation (F2), as compared to the meiosis of the two parental strains. We found a significant reduction of mating success in F1 in one direction of the cross and a high level of microsatellite markers showing transmission ratio distortion in the F2 progeny. Our results support the existence of post-zygotic reproductive isolation between the two laboratory strains and are in accordance with the marked level of genetic differentiation that was recovered between individuals of the two strains collected from the field. Altogether these results provide additional evidence in favor of a sibling species status for the two strains.

MODELING OF ELECTRONIC GASOLINE INJECTION PROCESSES IN TWO STROKE ENGINE

Directory of Open Access Journals (Sweden)

Hraivoronskyi, Y.

2013-06-01

Full Text Available Basic provision of the processes developed mode, occurring in ignition fuel system with electronically controlled two stroke engine with positive ignition are given. Fuel injection process’ calculation results for the case of placing fuel injector into intake system presented.

Nanotubule and Tour Molecule Based Molecular Electronics: Suggestion for a Hybrid Approach

Science.gov (United States)

Srivastava, Deepak; Saini, Subhash (Technical Monitor)

1998-01-01

Recent experimental and theoretical attempts and results indicate two distinct broad pathways towards future molecular electronic devices and architectures. The first is the approach via Tour type ladder molecules and their junctions which can be fabricated with solution phase chemical approaches. Second are fullerenes or nanotubules and their junctions which may have better conductance, switching and amplifying characteristics but can not be made through well controlled and defined chemical means. A hybrid approach combining the two pathways to take advantage of the characteristics of both is suggested. Dimension and scale of such devices would be somewhere in between isolated molecule and nanotubule based devices but it maybe possible to use self-assembly towards larger functional and logicalunits.

Stuttering Intervention in Three Service Delivery Models (Direct, Hybrid, and Telepractice): Two Case Studies

OpenAIRE

VALENTINE, DANIEL T.

2015-01-01

This study assessed outcomes in stuttering intervention across three service delivery models: direct, hybrid, and telepractice for two 11-year old children who stutter. The goal of the study was to investigate whether short-term goals were maintained through the telepractice sessions. The Stuttering Severity Instrument, Fourth Edition (SSI-4) was administered to each child before and after each intervention period and weekly fluency samples (percentage of stuttered syllables in a monologue) w...

Flow shear stabilization of hybrid electron-ion drift mode in tokamaks

International Nuclear Information System (INIS)

Bai, L.

1999-01-01

In this paper, a model of sheared flow stabilization on hybrid electron-ion drift mode is proposed. At first, in the presence of dissipative trapped electrons, there exists an intrinsic oscillation mode in tokamak plasmas, namely hybrid dissipative trapped electron-ion temperature gradient mode (hereafter, called as hybrid electron-ion drift mode). This conclusion is in agreement with the observations in the simulated tokamak experiment on the CLM. Then, it is found that the coupling between the sheared flows and dissipative trapped electrons is proposed as the stabilization mechanism of both toroidal sheared flow and poloidal sheared flow on the hybrid electron-ion drift mode, that is, similar to the stabilizing effect of poloidal sheared flow on edge plasmas in tokamaks, in the presence of both dissipative trapped electrons and toroidal sheared flow, large toroidal sheared flow is always a strong stabilizing effect on the hybrid electron-ion drift mode in internal transport barrier location, too. This result is consistent with the experimental observations in JT-60U. (author)

Flow shear stabilization of hybrid electron-ion drift mode in tokamaks

International Nuclear Information System (INIS)

Bai, L.

2001-01-01

In this paper, a model of sheared flow stabilization on hybrid electron-ion drift mode is proposed. At first, in the presence of dissipative trapped electrons, there exists an intrinsic oscillation mode in tokamak plasmas, namely hybrid dissipative trapped electron-ion temperature gradient mode (hereafter, called as hybrid electron-ion drift mode). This conclusion is in agreement with the observations in the simulated tokamak experiment on the CLM. Then, it is found that the coupling between the sheared flows and dissipative trapped electrons is proposed as the stabilization mechanism of both toroidal sheared flow and poloidal sheared flow on the hybrid electron-ion drift mode, that is, similar to the stabilizing effect of poloidal sheared flow on edge plasmas in tokamaks, in the presence of both dissipative trapped electrons and toroidal sheared flow, large toroidal sheared flow is always a strong stabilizing effect on the hybrid electron-ion drift mode in internal transport barrier location, too. This result is consistent with the experimental observations in JT-60U. (author)

Orbital order and effective mass enhancement in t2 g two-dimensional electron gases

Science.gov (United States)

Tolsma, John; Principi, Alessandro; Polini, Marco; MacDonald, Allan

2015-03-01

It is now possible to prepare d-electron two-dimensional electron gas systems that are confined near oxide heterojunctions and contain t2 g electrons with a density much smaller than one electron per metal atom. I will discuss a generic model that captures all qualitative features of electron-electron interaction physics in t2 g two-dimensional electron gas systems, and the use of a GW approximation to explore t2 g quasiparticle properties in this new context. t2 g electron gases contain a high density isotropic light mass xy component and low-density xz and yz anisotropic components with light and heavy masses in orthogonal directions. The high density light mass band screens interactions within the heavy bands. As a result the wave vector dependence of the self-energy is reduced and the effective mass is increased. When the density in the heavy bands is low, the difference in anisotropy between the two heavy bands favors orbital order. When orbital order does not occur, interactions still reshape the heavy-band Fermi surfaces. I will discuss these results in the context of recently reported magnetotransport experiments.

Three-input gate logic circuits on chemically assembled single-electron transistors with organic and inorganic hybrid passivation layers.

Science.gov (United States)

Majima, Yutaka; Hackenberger, Guillaume; Azuma, Yasuo; Kano, Shinya; Matsuzaki, Kosuke; Susaki, Tomofumi; Sakamoto, Masanori; Teranishi, Toshiharu

2017-01-01

Single-electron transistors (SETs) are sub-10-nm scale electronic devices based on conductive Coulomb islands sandwiched between double-barrier tunneling barriers. Chemically assembled SETs with alkanethiol-protected Au nanoparticles show highly stable Coulomb diamonds and two-input logic operations. The combination of bottom-up and top-down processes used to form the passivation layer is vital for realizing multi-gate chemically assembled SET circuits, as this combination enables us to connect conventional complementary metal oxide semiconductor (CMOS) technologies via planar processes. Here, three-input gate exclusive-OR (XOR) logic operations are demonstrated in passivated chemically assembled SETs. The passivation layer is a hybrid bilayer of self-assembled monolayers (SAMs) and pulsed laser deposited (PLD) aluminum oxide (AlO[Formula: see text]), and top-gate electrodes were prepared on the hybrid passivation layers. Top and two-side-gated SETs showed clear Coulomb oscillation and diamonds for each of the three available gates, and three-input gate XOR logic operation was clearly demonstrated. These results show the potential of chemically assembled SETs to work as logic devices with multi-gate inputs using organic and inorganic hybrid passivation layers.

Hybrid (Vlasov-Fluid) simulation of ion-acoustic solitons chain formation including trapped electrons

Energy Technology Data Exchange (ETDEWEB)

Behjat, E.; Aminmansoor, F.; Abbasi, H. [Faculty of Energy Engineering and Physics, Amirkabir University of Technology, P. O. Box 15875-4413, Tehran (Iran, Islamic Republic of)

2015-08-15

Disintegration of a Gaussian profile into ion-acoustic solitons in the presence of trapped electrons [H. Hakimi Pajouh and H. Abbasi, Phys. Plasmas 15, 082105 (2008)] is revisited. Through a hybrid (Vlasov-Fluid) model, the restrictions associated with the simple modified Korteweg de-Vries (mKdV) model are studied. For instance, the lack of vital information in the phase space associated with the evolution of electron velocity distribution, the perturbative nature of mKdV model which limits it to the weak nonlinear cases, and the special spatio-temporal scaling based on which the mKdV is derived. Remarkable differences between the results of the two models lead us to conclude that the mKdV model can only monitor the general aspects of the dynamics, and the precise picture including the correct spatio-temporal scales and the properties of solitons should be studied within the framework of hybrid model.

Two hybrid common x roseate terns fledge at Falkner Island, Connecticut

Science.gov (United States)

Zingo, James M.; Church, Christopher A.; Spendelow, Jeffrey A.

1994-01-01

Although these two similarly-sized species are sympatric throughout much of their breeding range, there are few published records of hybridization between Roseate (Sterna dougallii) and Common (S. hirundo) Terns. Records include at least five from Europe (Witherby and Ticehurst 1908, Perry 1972, Robbins 1974, Burggraeve 1977, van den Berg 1980) and only one from North America (Hays 1975), but we are aware of several unpublished records of hybridization at colonies in Massachusetts (I. Nisbet, pers. comm.) and New York (J. Burger, pers. comm.). Differences in sexual display probably serve as the principal barrier to hybridization (Palmer 1941 ), and in the northeastem United States where both species breed, Common Terns tend to nest in more open areas while Roseate Terns tend to nest in or under cover (Hays 1975, Nisbet 1981, Spendelow 1982, Burger and Gochfeld 1988).From 1984 through 1993, we recorded several instances of interbreeding in a mixed colony of several thousand Common Terns and a few hundred Roseates at the Falkner Island Unit of the Stewart B. McKinney National Wildlife Refuge. This 2-ha island is located at 41 °13'N and 72° 39'W in Long Island Sound, approximately 5 km off the coast of Guilford, Connecticut. Spendelow (1982) briefly described the island and the areas used by the nesting terns; a more detailed description of the island is in Helander (1988). The mixed pair we observed in 1993 nested in a subcolony of about 25 pairs of Roseates on the southeast section of the island's rocky beach, where we put out 30 boxes to create more protected nest sites for Roseate Terns. Here we present a summary of their successful nesting, which we followed almost daily from several days prior to the laying of the first egg until departure of these birds from the colony site.

Simulation of electron beam from two strip electron guns and control of power density by rotation of gun

International Nuclear Information System (INIS)

Sahu, G K; Baruah, S; Thakur, K B

2012-01-01

Electron beam is preferably used for large scale evaporation of refractory materials. Material evaporation from a long and narrow source providing a well collimated wedge shaped atomic beam has applications in isotopic purification of metals relevant to nuclear industry. The electron beam from an electron gun with strip type filament provides a linear heating source. However, the high power density of the electron beam can lead to turbulence of the melt pool and undesirable splashing of molten metal. For obtaining quiet surface evaporation, the linear electron beam is generally scanned along its length. To further reduce the power density to maintain quiet evaporation the width of the vapour source can be controlled by rotating the electron gun on its plane, thereby scanning an inclined beam over the molten pool. The rotation of gun has further advantages. When multiple strip type electron guns are used for scaling up evaporation length, a dark zone appears between two beams due to physical separation of adjacent guns. This dark zone can be reduced by rotating the gun and thereby bringing two adjacent beams closer. The paper presented here provides the simulation results of the electron beam trajectory and incident power density originating from two strip electron guns by using in-house developed code. The effect of electron gun rotation on the electron beam trajectory and power density is studied. The simulation result is experimentally verified with the image of molten pool and heat affected zone taken after experiment. This technique can be gainfully utilized in controlling the time averaged power density of the electron beam and obtaining quiet evaporation from the metal molten pool.

A comparison and benchmark of two electron cloud packages

Energy Technology Data Exchange (ETDEWEB)

Lebrun, Paul L.G.; Amundson, James F; Spentzouris, Panagiotis G; Veitzer, Seth A

2012-01-01

We present results from precision simulations of the electron cloud (EC) problem in the Fermilab Main Injector using two distinct codes. These two codes are (i)POSINST, a F90 2D+ code, and (ii)VORPAL, a 2D/3D electrostatic and electromagnetic code used for self-consistent simulations of plasma and particle beam problems. A specific benchmark has been designed to demonstrate the strengths of both codes that are relevant to the EC problem in the Main Injector. As differences between results obtained from these two codes were bigger than the anticipated model uncertainties, a set of changes to the POSINST code were implemented. These changes are documented in this note. This new version of POSINST now gives EC densities that agree with those predicted by VORPAL, within {approx}20%, in the beam region. The root cause of remaining differences are most likely due to differences in the electrostatic Poisson solvers. From a software engineering perspective, these two codes are very different. We comment on the pros and cons of both approaches. The design(s) for a new EC package are briefly discussed.

Two dimensional localization of electrons and positrons under high counting rate

International Nuclear Information System (INIS)

Barbosa, A.F.; Anjos, J.C.; Sanchez-Hernandez, A.; Pepe, I.M.; Barros, N.

1997-12-01

The construction of two wire chambers for the experiment E831 at Fermilab is reported. Each chamber includes three wire planes - one anode and two orthogonal cathodes - in which the wires operate as independent proportional counters. One of the chambers is rotated with respect to the other, so that four position coordinates may be encoded for a charged particle crossing both chambers. Spatial resolution is determined by the wire pitch: 1 mm for cathodes, 2 mm for anodes. 320 electronic channels are involved in the detection system readout. Global counting rates in excess to 10 7 events per second have been measured, while the average electron-positron beam intensity may be as high as 3 x 10 7 events per second. (author)

Role of electron back action on photons in hybridizing double-layer graphene plasmons with localized photons

Science.gov (United States)

Huang, Danhong; Iurov, Andrii; Gumbs, Godfrey

2018-05-01

In this paper, we deal with the electromagnetic coupling between an incident surface-plasmon-polariton wave and relativistic electrons in two graphene layers. Our previous investigation was limited to single-layer graphene (Iurov et al 2017 Phys. Rev. B 96 081408). However, the present work, is both an expanded and extended version of this previous Phys. Rev. B paper after having included very detailed theoretical formalisms and extensive comparisons of results from either one or two graphene layers embedded in a dielectric medium. The additional retarded Coulomb interaction between two graphene layers will compete with the coupling between the single graphene layer and the surface of a conductor. Consequently, some distinctive features, such as triply-hybridized absorption peaks and a new acoustic-like graphene plasmon mode within the anticrossing region, have been found for the double-layer graphene system. Physically, our theory is self-consistent, in comparison with a commonly adopted perturbative theory, for studying hybrid light-plasmon modes and the electron back action on photons. Instead of usual radiation or grating-deflection field coupling, a surface-plasmon-polariton localized field coupling is introduced with completely different dispersion relations for radiative (small wave numbers) and evanescent (large wave numbers) field modes. Technically, the exactly calculated effective scattering matrix for this theory can be employed to construct an effective-medium theory in order to improve the accuracy of the well-known finite-difference time-domain method for solving Maxwell’s equations numerically. Practically, the predicted triply-hybridized absorption peaks can excite polaritons only, giving rise to a possible polariton-condensation based laser.

A hybrid two-component system protein from Azospirillum brasilense Sp7 was involved in chemotaxis.

Science.gov (United States)

Cui, Yanhua; Tu, Ran; Wu, Lixian; Hong, Yuanyuan; Chen, Sanfeng

2011-09-20

We here report the sequence and functional analysis of org35 of Azospirillum brasilense Sp7, which was originally identified to be able to interact with NifA in yeast-two-hybrid system. The org35 encodes a hybrid two-component system protein, including N-terminal PAS domains, a histidine kinase (HPK) domain and a response regulator (RR) domain in C-terminal. To determine the function of the Org35, a deletion-insertion mutant in PAS domain [named Sp7353] and a complemental strain Sp7353C were constructed. The mutant had reduced chemotaxis ability compared to that of wild-type, and the complemental strain was similar to the wild-type strain. These data suggested that the A. brasilense org35 played a key role in chemotaxis. Variants containing different domains of the org35 were expressed, and the functions of these domains were studied in vitro. Phosphorylation assays in vitro demonstrated that the HPK domain of Org35 possessed the autokinase activity and that the phosphorylated HPK was able to transfer phosphate groups to the RR domain. The result indicated Org35 was a phosphorylation-communicating protein. Copyright © 2010 Elsevier GmbH. All rights reserved.

Sheath and heat flow of a two-electron-temperature plasma in the presence of electron emission

International Nuclear Information System (INIS)

Sato, Kunihiro; Miyawaki, Fujio

1992-01-01

The electrostatic sheath and the heat flow of a two-electron-temperature plasma in the presence of electron emission are investigated analytically. It is shown that the energy flux is markedly enhanced to a value near the electron free-flow energy flux as a result of considerable reduction of the sheath potential due to electron emission if the fraction of hot electrons at the sheath edge is much smaller than one. If the hot- to cold-electron temperature ratio is of the order of ten and the hot electron density is comparable to the cold electron density, the action of the sheath as a thermal insulator is improved as a result of suppression of electron emission due to the space-charge effect of hot electrons. (author)

Two-dimensional photonic crystal bandedge laser with hybrid perovskite thin film for optical gain

Energy Technology Data Exchange (ETDEWEB)

Cha, Hyungrae [Department of Biophysics and Chemical Biology, Seoul National University, Seoul 08826 (Korea, Republic of); Inter-University Semiconductor Research Center, Seoul National University, Seoul 08826 (Korea, Republic of); Bae, Seunghwan [Department of Materials Science and Engineering, Seoul National University, Seoul 08826 (Korea, Republic of); Lee, Myungjae [Inter-University Semiconductor Research Center, Seoul National University, Seoul 08826 (Korea, Republic of); Department of Physics and Astronomy, Seoul National University, Seoul 08826 (Korea, Republic of); Jeon, Heonsu, E-mail: hsjeon@snu.ac.kr [Department of Biophysics and Chemical Biology, Seoul National University, Seoul 08826 (Korea, Republic of); Inter-University Semiconductor Research Center, Seoul National University, Seoul 08826 (Korea, Republic of); Department of Physics and Astronomy, Seoul National University, Seoul 08826 (Korea, Republic of)

2016-05-02

We report optically pumped room temperature single mode laser that contains a thin film of hybrid perovskite, an emerging photonic material, as gain medium. Two-dimensional square lattice photonic crystal (PhC) backbone structure enables single mode laser operation via a photonic bandedge mode, while a thin film of methyl-ammonium lead iodide (CH{sub 3}NH{sub 3}PbI{sub 3}) spin-coated atop provides optical gain for lasing. Two kinds of bandedge modes, Γ and M, are employed, and both devices laser in single mode at similar laser thresholds of ∼200 μJ/cm{sup 2} in pulse energy density. Polarization dependence measurements reveal a clear difference between the two kinds of bandedge lasers: isotropic for the Γ-point laser and highly anisotropic for the M-point laser. These observations are consistent with expected modal properties, confirming that the lasing actions indeed originate from the corresponding PhC bandedge modes.

Electron imaging with Medipix2 hybrid pixel detector

International Nuclear Information System (INIS)

McMullan, G.; Cattermole, D.M.; Chen, S.; Henderson, R.; Llopart, X.; Summerfield, C.; Tlustos, L.; Faruqi, A.R.

2007-01-01

The electron imaging performance of Medipix2 is described. Medipix2 is a hybrid pixel detector composed of two layers. It has a sensor layer and a layer of readout electronics, in which each 55 μmx55 μm pixel has upper and lower energy discrimination and MHz rate counting. The sensor layer consists of a 300 μm slab of pixellated monolithic silicon and this is bonded to the readout chip. Experimental measurement of the detective quantum efficiency, DQE(0) at 120 keV shows that it can reach ∼85% independent of electron exposure, since the detector has zero noise, and the DQE(Nyquist) can reach ∼35% of that expected for a perfect detector (4/π 2 ). Experimental measurement of the modulation transfer function (MTF) at Nyquist resolution for 120 keV electrons using a 60 keV lower energy threshold, yields a value that is 50% of that expected for a perfect detector (2/π). Finally, Monte Carlo simulations of electron tracks and energy deposited in adjacent pixels have been performed and used to calculate expected values for the MTF and DQE as a function of the threshold energy. The good agreement between theory and experiment allows suggestions for further improvements to be made with confidence. The present detector is already very useful for experiments that require a high DQE at very low doses

Electron imaging with Medipix2 hybrid pixel detector.

Science.gov (United States)

McMullan, G; Cattermole, D M; Chen, S; Henderson, R; Llopart, X; Summerfield, C; Tlustos, L; Faruqi, A R

2007-01-01

The electron imaging performance of Medipix2 is described. Medipix2 is a hybrid pixel detector composed of two layers. It has a sensor layer and a layer of readout electronics, in which each 55 microm x 55 microm pixel has upper and lower energy discrimination and MHz rate counting. The sensor layer consists of a 300 microm slab of pixellated monolithic silicon and this is bonded to the readout chip. Experimental measurement of the detective quantum efficiency, DQE(0) at 120 keV shows that it can reach approximately 85% independent of electron exposure, since the detector has zero noise, and the DQE(Nyquist) can reach approximately 35% of that expected for a perfect detector (4/pi(2)). Experimental measurement of the modulation transfer function (MTF) at Nyquist resolution for 120 keV electrons using a 60 keV lower energy threshold, yields a value that is 50% of that expected for a perfect detector (2/pi). Finally, Monte Carlo simulations of electron tracks and energy deposited in adjacent pixels have been performed and used to calculate expected values for the MTF and DQE as a function of the threshold energy. The good agreement between theory and experiment allows suggestions for further improvements to be made with confidence. The present detector is already very useful for experiments that require a high DQE at very low doses.

Analytic solution of the two-dimensional Fokker-Planck equation governing stochastic ion heating by a lower hybrid wave

International Nuclear Information System (INIS)

Malescio, G.

1981-04-01

The two-dimensional Fokker-Planck equation describing the ion motion in a coherent lower hybrid wave above the stochasticity threshold is analytically solved. An expression is given for the steady state power dissipation

A new coupling mechanism between two graphene electron waveguides for ultrafast switching

Science.gov (United States)

Huang, Wei; Liang, Shi-Jun; Kyoseva, Elica; Ang, Lay Kee

2018-03-01

In this paper, we report a novel coupling between two graphene electron waveguides, in analogy the optical waveguides. The design is based on the coherent quantum mechanical tunneling of Rabi oscillation between the two graphene electron waveguides. Based on this coupling mechanism, we propose that it can be used as an ultrafast electronic switching device. Based on a modified coupled mode theory, we construct a theoretical model to analyze the device characteristics, and predict that the switching speed is faster than 1 ps and the on-off ratio exceeds 106. Due to the long mean free path of electrons in graphene at room temperature, the proposed design avoids the limitation of low temperature operation required in the traditional design by using semiconductor quantum-well structure. The layout of our design is similar to that of a standard complementary metal-oxide-semiconductor transistor that should be readily fabricated with current state-of-art nanotechnology.

Possible natural hybridization of two morphologically distinct species of Acropora (Cnidaria, Scleractinia in the Pacific: fertilization and larval survival rates.

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Naoko Isomura

Full Text Available Natural hybridization of corals in the Indo-Pacific has been considered rather rare. However, field studies have observed many corals with intermediate interspecific or unusual morphologies. Given that the existence of F1 hybrids with intermediate interspecific morphologies has been proven in the Caribbean, hybrids may also inhabit the Indo-Pacific and occur more frequently than expected. In this study, we focused on two morphologically different species, Acropora florida and A. intermedia, and performed crossing experiments at Akajima Island, Japan. Results showed that these species could hybridize in both directions via eggs and sperm, but that fertilization rates significantly differed according to which species provided eggs. These results are similar to those reported from the Caribbean. Although all embryos developed normally to the planular larval stage, the developmental processes of some hybrid embryos were delayed by approximately 1 h compared with conspecific embryos, suggesting that fertilization occurred 1 h later in interspecific crosses than in intraspecific crosses. More successful hybridization could occur under conditions with low numbers of conspecific colonies. Additionally, a comparison of survival rates between hybrid and intraspecific larvae revealed that intra- and interspecific larvae produced from eggs of A. florida survived for significantly longer than those produced from eggs of A. intermedia. Considering these data, under specific conditions, hybrids can be expected to be produced and survive in nature in the Pacific. Furthermore, we identified one colony with intermediate morphology between A. florida and A. intermedia in the field. This colony was fertilized only by eggs of A. florida, with high fertilization rates, suggesting that this colony would be a hybrid of these two species and might be backcrossed.

Comparison of Two Hybrid Models for Forecasting the Incidence of Hemorrhagic Fever with Renal Syndrome in Jiangsu Province, China.

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Wei Wu

Full Text Available Cases of hemorrhagic fever with renal syndrome (HFRS are widely distributed in eastern Asia, especially in China, Russia, and Korea. It is proved to be a difficult task to eliminate HFRS completely because of the diverse animal reservoirs and effects of global warming. Reliable forecasting is useful for the prevention and control of HFRS.Two hybrid models, one composed of nonlinear autoregressive neural network (NARNN and autoregressive integrated moving average (ARIMA the other composed of generalized regression neural network (GRNN and ARIMA were constructed to predict the incidence of HFRS in the future one year. Performances of the two hybrid models were compared with ARIMA model.The ARIMA, ARIMA-NARNN ARIMA-GRNN model fitted and predicted the seasonal fluctuation well. Among the three models, the mean square error (MSE, mean absolute error (MAE and mean absolute percentage error (MAPE of ARIMA-NARNN hybrid model was the lowest both in modeling stage and forecasting stage. As for the ARIMA-GRNN hybrid model, the MSE, MAE and MAPE of modeling performance and the MSE and MAE of forecasting performance were less than the ARIMA model, but the MAPE of forecasting performance did not improve.Developing and applying the ARIMA-NARNN hybrid model is an effective method to make us better understand the epidemic characteristics of HFRS and could be helpful to the prevention and control of HFRS.

Two-electron spin correlations in precision placed donors in silicon.

Science.gov (United States)

Broome, M A; Gorman, S K; House, M G; Hile, S J; Keizer, J G; Keith, D; Hill, C D; Watson, T F; Baker, W J; Hollenberg, L C L; Simmons, M Y

2018-03-07

Substitutional donor atoms in silicon are promising qubits for quantum computation with extremely long relaxation and dephasing times demonstrated. One of the critical challenges of scaling these systems is determining inter-donor distances to achieve controllable wavefunction overlap while at the same time performing high fidelity spin readout on each qubit. Here we achieve such a device by means of scanning tunnelling microscopy lithography. We measure anti-correlated spin states between two donor-based spin qubits in silicon separated by 16 ± 1 nm. By utilising an asymmetric system with two phosphorus donors at one qubit site and one on the other (2P-1P), we demonstrate that the exchange interaction can be turned on and off via electrical control of two in-plane phosphorus doped detuning gates. We determine the tunnel coupling between the 2P-1P system to be 200 MHz and provide a roadmap for the observation of two-electron coherent exchange oscillations.

Screening and identification of host proteins interacting with Theileria annulata cysteine proteinase (TaCP by yeast-two-hybrid system

Directory of Open Access Journals (Sweden)

Shuaiyang Zhao

2017-10-01

Full Text Available Abstract Background Theileria annulata can infect monocytes/macrophages and B lymphocytes and causes severe lymphoproliferative disease in ruminants. Meanwhile, infection by T. annulata leads to the permanent proliferation of cell population through regulating signaling pathways of host cells. Cysteine proteinases (CPs are one kind of protein hydrolase and usually play critical roles in parasite virulence, host invasion, nutrition and host immune response. However, the biological function of T. annulata CP (TaCP is still unclear. In this study, a yeast-two-hybrid assay was performed to screen host proteins interacting with TaCP, to provide information to help our understanding of the molecular mechanisms between T. annulata and host cells. Methods The cDNA from purified bovine B cells was inserted into pGADT7-SfiI vector (pGADT7-SfiI-BcDNA, Prey plasmid for constructing the yeast two-hybrid cDNA library. TaCP was cloned into the pGBKT7 vector (pGBKT7-TaCP and was considered as bait plasmid after evaluating the expression, auto-activation and toxicity tests in the yeast strain Y2HGold. The yeast two-hybrid screening was carried out via co-transforming bait and prey plasmids into yeast strain Y2HGold. Sequences of positive preys were analyzed using BLAST, Gene Ontology, UniProt and STRING. Results Two host proteins, CRBN (Bos taurus cereblon transcript variant X2 and Ppp4C (Bos indicus protein phosphatase 4 catalytic subunit were identified to interact with TaCP. The results of functional analysis showed that the two proteins were involved in many cellular processes, such as ubiquitylation regulation, microtubule organization, DNA repair, cell apoptosis and maturation of spliceosomal snRNPs. Conclusions This study is the first to screen the host proteins of bovine B cells interacting with TaCP, and 2 proteins, CRBN and Ppp4C, were identified using yeast two-hybrid technique. The results of functional analysis suggest that the two proteins are

Electrostatic modulation of periodic potentials in a two-dimensional electron gas: From antidot lattice to quantum dot lattice

Energy Technology Data Exchange (ETDEWEB)

Goswami, Srijit; Aamir, Mohammed Ali; Shamim, Saquib; Ghosh, Arindam [Department of Physics, Indian Institute of Science, Bangalore 560 012 (India); Siegert, Christoph; Farrer, Ian; Ritchie, David A. [Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Pepper, Michael [Department of Electrical and Electronic Engineering, University College, London WC1E 7JE (United Kingdom)

2013-12-04

We use a dual gated device structure to introduce a gate-tuneable periodic potential in a GaAs/AlGaAs two dimensional electron gas (2DEG). Using only a suitable choice of gate voltages we can controllably alter the potential landscape of the bare 2DEG, inducing either a periodic array of antidots or quantum dots. Antidots are artificial scattering centers, and therefore allow for a study of electron dynamics. In particular, we show that the thermovoltage of an antidot lattice is particularly sensitive to the relative positions of the Fermi level and the antidot potential. A quantum dot lattice, on the other hand, provides the opportunity to study correlated electron physics. We find that its current-voltage characteristics display a voltage threshold, as well as a power law scaling, indicative of collective Coulomb blockade in a disordered background.

Electrostatic modulation of periodic potentials in a two-dimensional electron gas: From antidot lattice to quantum dot lattice

International Nuclear Information System (INIS)

Goswami, Srijit; Aamir, Mohammed Ali; Shamim, Saquib; Ghosh, Arindam; Siegert, Christoph; Farrer, Ian; Ritchie, David A.; Pepper, Michael

2013-01-01

We use a dual gated device structure to introduce a gate-tuneable periodic potential in a GaAs/AlGaAs two dimensional electron gas (2DEG). Using only a suitable choice of gate voltages we can controllably alter the potential landscape of the bare 2DEG, inducing either a periodic array of antidots or quantum dots. Antidots are artificial scattering centers, and therefore allow for a study of electron dynamics. In particular, we show that the thermovoltage of an antidot lattice is particularly sensitive to the relative positions of the Fermi level and the antidot potential. A quantum dot lattice, on the other hand, provides the opportunity to study correlated electron physics. We find that its current-voltage characteristics display a voltage threshold, as well as a power law scaling, indicative of collective Coulomb blockade in a disordered background

Two-electron states in double quantum dot in direct electric field

International Nuclear Information System (INIS)

Burdov, V.A.

2001-01-01

One determined analytically the wave functions of stationary states and the spectrum of two-electron system in symmetric binary quantum point. It is shown that in the normal state at the absence of external electric field the electrons due to the Coulomb blockade can not be collectively in one quantum point. In the external electric field the situation changes. When a certain critical value of field intensity is reached the probability of detection of both electrons in one quantum point by a jump increases from zero up to 1 [ru

OWL: A code for the two-center shell model with spherical Woods-Saxon potentials

Science.gov (United States)

Diaz-Torres, Alexis

2018-03-01

A Fortran-90 code for solving the two-center nuclear shell model problem is presented. The model is based on two spherical Woods-Saxon potentials and the potential separable expansion method. It describes the single-particle motion in low-energy nuclear collisions, and is useful for characterizing a broad range of phenomena from fusion to nuclear molecular structures.

A Tale of Two Sections: An Experiment to Compare the Effectiveness of a Hybrid versus a Traditional Lecture Format in Introductory Microbiology

OpenAIRE

Adams, Alison E. M.; Randall, Shelby; Traustad?ttir, Tinna

2015-01-01

Two sections of an introductory microbiology course were taught by one instructor. One was taught through a hybrid format and the other through a traditional format. Students were randomly assigned to the two sections. Both sections were provided with identical lecture materials, in-class worksheets, in-class assessments, and extra credit opportunities; the main difference was in the way the lecture material was delivered?online for the hybrid section and in person for the traditional section...

A two-dimensional organic–inorganic hybrid compound, poly[(ethylenediaminetri-μ-oxido-oxidocopper(IImolybdenum(VI

Directory of Open Access Journals (Sweden)

Mehtap Emirdag-Eanes

2008-10-01

Full Text Available A new organic–inorganic two-dimensional hybrid compound, [CuMoO4(C2H8N2], has been hydrothermally synthesized at 443 K. The unit cell contains layers composed of CuN2O4 octahedra and MoO4 tetrahedra. Corner-sharing MoO4 and CuN2O4 polyhedra form CuMoO4 bimetallic sites that are joined together through O atoms, forming an edge-sharing Cu2Mo2O4 chain along the c axis. The one-dimensional chains are further linked through bridging O atoms that join the Cu and Mo atoms into respective chains along the b axis, thus establishing layers in the bc plane. The ethylenediamine ligand is coordinated to the Cu atom through its two N atoms and is oriented perpendicularly to the two-dimensional –Cu—O—Mo– layers. The average distance between adjacent layers, as calculated by consideration of the closest and furthest distances between two layers, is 8.7 Å. The oxidation states of the Mo and Cu atoms of VI and II, respectively, were confirmed by bond-valence sum calculations.

Search for two-neutrino double electron capture on 124Xe with the XMASS-I detector

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K. Abe

2016-08-01

Full Text Available Double electron capture is a rare nuclear decay process in which two orbital electrons are captured simultaneously in the same nucleus. Measurement of its two-neutrino mode would provide a new reference for the calculation of nuclear matrix elements whereas observation of its neutrinoless mode would demonstrate lepton number violation. A search for two-neutrino double electron capture on 124Xe is performed using 165.9 days of data collected with the XMASS-I liquid xenon detector. No significant excess above background was observed and we set a lower limit on the half-life as 4.7×1021 years at 90% confidence level. The obtained limit has ruled out parts of some theoretical expectations. We obtain a lower limit on the 126Xe two-neutrino double electron capture half-life of 4.3×1021 years at 90% confidence level as well.

Regular and chaotic motion of two dimensional electrons in a strong magnetic field

International Nuclear Information System (INIS)

Bar-Lev, Oded; Levit, Shimon.

1992-05-01

For two dimensional system of electrons in a strong magnetic field a standard approximation is the projection on a single Landau level. The resulting Hamiltonian is commonly treated semiclassically. An important element in applying the semiclassical approximation is the integrability of the corresponding classical system. We discuss the relevant integrability conditions and give a simple example of a non-integrable system-two interacting electrons in the presence of two impurities-which exhibits a coexistence of regular and chaotic classical motions. Since the inverse of the magnetic field plays the role of the Planck constant in these problems, one has the opportunity to control the 'closeness' of chaotic physical systems to the classical limit. (author)

A Study of the Surface Structure of Polymorphic Graphene and Other Two-Dimensional Materials for Use in Novel Electronics and Organic Photovoltaics

Science.gov (United States)

Grady, Maxwell

For some time there has been interest in the fundamental physical properties of low- dimensional material systems. The discovery of graphene as a stable two-dimensional form of solid carbon lead to an exponential increase in research in two-dimensional and other re- duced dimensional systems. It is now known that there is a wide range of materials which are stable in two-dimensional form. These materials span a large configuration space of struc- tural, mechanical, and electronic properties, which results in the potential to create novel electronic devices from nano-scale heterostructures with exactly tailored device properties. Understanding the material properties at the nanoscale level requires specialized tools to probe materials with atomic precision. Here I present the growth and analysis of a novel graphene-ruthenium system which exhibits unique polymorphism in its surface structure, hereby referred to as polymorphic graphene. Scanning Tunneling Microscopy (STM) investigations of the polymorphic graphene surface reveal a periodically rippled structure with a vast array of domains, each exhibiting xvia unique moire period. The majority of moire domains found in this polymorphic graphene system are previously unreported in past studies of the structure of graphene on ruthenium. To better understand many of the structural properties of this system, characterization methods beyond those available at the UNH surface science lab are employed. Further investigation using Low Energy Electron Microscopy (LEEM) has been carried out at Sandia National Laboratory's Center for Integrated Nanotechnology and the Brookhaven National Laboratory Center for Functional Nanomaterials. To aid in analysis of the LEEM data, I have developed an open source software package to automate extraction of electron reflectivity curves from real space and reciprocal space data sets. This software has been used in the study of numerous other two-dimensional materials beyond graphene. When

Elaboration, structural, vibrational and optical investigation of a two-dimensional self-assembled organic–inorganic hybrid compound

International Nuclear Information System (INIS)

Dammak, T.; Boughzala, H.; Mlayah, A.; Abid, Y.

2016-01-01

Single crystals of a hybrid organic/inorganic material with the formula (C 4 N 3 H 16 )Cl[CuCl 4 ] were elaborated and studied by X-ray diffraction, and photoluminescence. The crystals consist of a self-assembled multilayer structure with a Pnam space group. The structure is built up from the staking of infinite two-dimensional layers of CuCl 6 corner-sharing octahedra, separated by organic (C 4 N 3 H 16 ) 3+ chains. Such a structure may be regarded as a multi quantum well system, in which CuCl 6 layers act as semiconductor wells and the organic molecules act as insulator barriers Furthermore, the room temperature IR and Raman spectra of the title compound were recorded and analyzed. For optical investigations, thin films have been prepared by spin-coating method from the ethanol solution of the material. Optical absorption spectra shows characteristic absorptions of CuCl-based layered perovskite centered at 300 and 380 nm, whereas the photoluminescence spectra shows a bleu intense emission around 420 nm, associated to radiative recombination of confined excitons in the CuCl 6 Quantum wells.

Confined quantum systems: spectral properties of two-electron quantum dots

International Nuclear Information System (INIS)

Sako, T; Diercksen, G H F

2003-01-01

The spectrum, electron-density distribution and ground-state correlation energy of two electrons confined by an anisotropic harmonic oscillator potential have been studied for different confinement strengths ω by using the quantum chemical configuration interaction (CI) method employing a large Cartesian anisotropic Gaussian basis set and a full CI wavefunction. Energy level diagrams and electron-density distributions are displayed for selected electronic states and confinement parameters. The total energy and spacing between energy levels increase in all cases with increasing ω. The energy level structure cannot be matched by scaling with respect to ω. The correlation energy of the ground state is comparable in magnitude to that of the helium atom. It increases for increasing ω. The percentage of the correlation energy with respect to the total energy of the ground state is considerably larger than that of the helium atom

Wave mode instabilities in a two-stream free-electron laser with a background plasma

International Nuclear Information System (INIS)

Nadrifard, Shabnam; Maraghechi, B; Mohsenpour, T

2013-01-01

A theory is presented for a two-stream free-electron laser (FEL) with a background plasma. A dispersion relation (DR) for the unstable couplings of wave modes is derived using fluid formulation. This DR is solved numerically to find the unstable modes and their growth rate. The effect of the velocity difference of the two electron beams as well as the background plasma on the FEL resonance and the two-stream instability is studied. It is shown that their separate as well as combined effects can increase the growth rates. (paper)

General solution of the Dirac equation for quasi-two-dimensional electrons

Energy Technology Data Exchange (ETDEWEB)

Eremko, Alexander, E-mail: eremko@bitp.kiev.ua [Bogolyubov Institute for Theoretical Physics, Metrologichna Str., 14-b, Kyiv, 03680 (Ukraine); Brizhik, Larissa, E-mail: brizhik@bitp.kiev.ua [Bogolyubov Institute for Theoretical Physics, Metrologichna Str., 14-b, Kyiv, 03680 (Ukraine); Loktev, Vadim, E-mail: vloktev@bitp.kiev.ua [Bogolyubov Institute for Theoretical Physics, Metrologichna Str., 14-b, Kyiv, 03680 (Ukraine); National Technical University of Ukraine “KPI”, Peremohy av., 37, Kyiv, 03056 (Ukraine)

2016-06-15

The general solution of the Dirac equation for quasi-two-dimensional electrons confined in an asymmetric quantum well, is found. The energy spectrum of such a system is exactly calculated using special unitary operator and is shown to depend on the electron spin polarization. This solution contains free parameters, whose variation continuously transforms one known particular solution into another. As an example, two different cases are considered in detail: electron in a deep and in a strongly asymmetric shallow quantum well. The effective mass renormalized by relativistic corrections and Bychkov–Rashba coefficients are analytically obtained for both cases. It is demonstrated that the general solution transforms to the particular solutions, found previously (Eremko et al., 2015) with the use of spin invariants. The general solution allows to establish conditions at which a specific (accompanied or non-accompanied by Rashba splitting) spin state can be realized. These results can prompt the ways to control the spin degree of freedom via the synthesis of spintronic heterostructures with the required properties.

Optimized calculation of the synergy conditions between electron cyclotron current drive and lower hybrid current drive on EAST

International Nuclear Information System (INIS)

Wei Wei; Ding Bo-Jiang; Li Miao-Hui; Zhang Xin-Jun; Wang Xiao-Jie; Peysson, Y; Decker, J; Zhang Lei

2016-01-01

The optimized synergy conditions between electron cyclotron current drive (ECCD) and lower hybrid current drive (LHCD) with normal parameters of the EAST tokamak are studied by using the C3PO/LUKE code based on the understanding of the synergy mechanisms so as to obtain a higher synergistic current and provide theoretical reference for the synergistic effect in the EAST experiment. The dependences of the synergistic effect on the parameters of two waves (lower hybrid wave (LHW) and electron cyclotron wave (ECW)), including the radial position of the power deposition, the power value of the LH and EC waves, and the parallel refractive indices of the LHW (N ∥ ) are presented and discussed. (paper)

Rapid radiations of both kiwifruit hybrid lineages and their parents shed light on a two-layer mode of species diversification.

Science.gov (United States)

Liu, Yifei; Li, Dawei; Zhang, Qiong; Song, Chi; Zhong, Caihong; Zhang, Xudong; Wang, Ying; Yao, Xiaohong; Wang, Zupeng; Zeng, Shaohua; Wang, Ying; Guo, Yangtao; Wang, Shuaibin; Li, Xinwei; Li, Li; Liu, Chunyan; McCann, Honour C; He, Weiming; Niu, Yan; Chen, Min; Du, Liuwen; Gong, Junjie; Datson, Paul M; Hilario, Elena; Huang, Hongwen

2017-07-01

Reticulate speciation caused by interspecific hybridization is now recognized as an important mechanism in the creation of biological diversity. However, depicting the patterns of phylogenetic networks for lineages that have undergone interspecific gene flow is challenging. Here we sequenced 25 taxa representing natural diversity in the genus Actinidia with an average mapping depth of 26× on the reference genome to reconstruct their reticulate history. We found evidence, including significant gene tree discordance, cytonuclear conflicts, and changes in genome-wide heterozygosity across taxa, collectively supporting extensive reticulation in the genus. Furthermore, at least two separate parental species pairs were involved in the repeated origin of the hybrid lineages, in some of which a further phase of syngameon was triggered. On the basis of the elucidated hybridization relationships, we obtained a highly resolved backbone phylogeny consisting of taxa exhibiting no evidence of hybrid origin. The backbone taxa have distinct demographic histories and are the product of recent rounds of rapid radiations via sorting of ancestral variation under variable climatic and ecological conditions. Our results suggest a mode for consecutive plant diversification through two layers of radiations, consisting of the rapid evolution of backbone lineages and the formation of hybrid swarms derived from these lineages. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Elimination of two atomic electrons by a single high energy photon

International Nuclear Information System (INIS)

Amusia, M.Y.; Ioffe, A.F.

1993-01-01

This report discusses the following topics: mechanism of two-electron photoionization; multiple photoionization near inner shell thresholds; double ionization accompanying compton-effect; and the investigation of secondary photon emission in coincidence with double charged ion production

Thermodynamic models to elucidate the enantioseparation of drugs with two stereogenic centers by micellar electrokinetic chromatography.

Science.gov (United States)

Guo, Xuming; Liu, Qiuxia; Hu, Shaoqiang; Guo, Wenbo; Yang, Zhuo; Zhang, Yonghua

2017-08-25

An equilibrium model depicting the simultaneous protonation of chiral drugs and partitioning of protonated ions and neutral molecules into chiral micelles in micellar electrokinetic chromatography (MEKC) has been introduced. It was used for the prediction and elucidation of complex changes in migration order patterns with experimental conditions in the enantioseparation of drugs with two stereogenic centers. Palonosetron hydrochloride (PALO), a weakly basic drug with two stereogenic centers, was selected as a model drug. Its four stereoisomers were separated by MEKC using sodium cholate (SC) as chiral selector and surfactant. Based on the equilibrium model, equations were derived for a calculation of the effective mobility and migration time of each stereoisomer at a certain pH. The migration times of four stereoisomers at different pHs were calculated and then the migration order patterns were constructed with derived equations. The results were in accord with the experiment. And the contribution of each mechanism to the separation and its influence on the migration order pattern was analyzed separately by introducing virtual isomers, i.e., hypothetical stereoisomers with only one parameter changed relative to a real PALO stereoisomer. A thermodynamic model for a judgment of the correlation of interactions between two stereogenic centers of stereoisomers and chiral selector was also proposed. According to this model, the interactions of two stereogenic centers of PALO stereoisomers in both neutral molecules and protonated ions with chiral selector are not independent, so the chiral recognition in each pair of enantiomers as well as the recognition for diastereomers is not simply the algebraic sum of the contributions of two stereogenic centers due to their correlation. Copyright © 2017 Elsevier B.V. All rights reserved.

Two-dimensional silicon and carbon monochalcogenides with the structure of phosphorene.

Science.gov (United States)

Rocca, Dario; Abboud, Ali; Vaitheeswaran, Ganapathy; Lebègue, Sébastien

2017-01-01

Phosphorene has recently attracted significant interest for applications in electronics and optoelectronics. Inspired by this material an ab initio study was carried out on new two-dimensional binary materials with a structure analogous to phosphorene. Specifically, carbon and silicon monochalcogenides have been considered. After structural optimization, a series of binary compounds were found to be dynamically stable in a phosphorene-like geometry: CS, CSe, CTe, SiO, SiS, SiSe, and SiTe. The electronic properties of these monolayers were determined using density functional theory. By using accurate hybrid functionals it was found that these materials are semiconductors and span a broad range of bandgap values and types. Similarly to phosphorene, the computed effective masses point to a strong in-plane anisotropy of carrier mobilities. The variety of electronic properties carried by these compounds have the potential to broaden the technological applicability of two-dimensional materials.

Two-dimensional silicon and carbon monochalcogenides with the structure of phosphorene

Directory of Open Access Journals (Sweden)

Dario Rocca

2017-06-01

Full Text Available Phosphorene has recently attracted significant interest for applications in electronics and optoelectronics. Inspired by this material an ab initio study was carried out on new two-dimensional binary materials with a structure analogous to phosphorene. Specifically, carbon and silicon monochalcogenides have been considered. After structural optimization, a series of binary compounds were found to be dynamically stable in a phosphorene-like geometry: CS, CSe, CTe, SiO, SiS, SiSe, and SiTe. The electronic properties of these monolayers were determined using density functional theory. By using accurate hybrid functionals it was found that these materials are semiconductors and span a broad range of bandgap values and types. Similarly to phosphorene, the computed effective masses point to a strong in-plane anisotropy of carrier mobilities. The variety of electronic properties carried by these compounds have the potential to broaden the technological applicability of two-dimensional materials.

The Solution of Two-Phase Inverse Stefan Problem Based on a Hybrid Method with Optimization

Directory of Open Access Journals (Sweden)

Yang Yu

2015-01-01

Full Text Available The two-phase Stefan problem is widely used in industrial field. This paper focuses on solving the two-phase inverse Stefan problem when the interface moving is unknown, which is more realistic from the practical point of view. With the help of optimization method, the paper presents a hybrid method which combines the homotopy perturbation method with the improved Adomian decomposition method to solve this problem. Simulation experiment demonstrates the validity of this method. Optimization method plays a very important role in this paper, so we propose a modified spectral DY conjugate gradient method. And the convergence of this method is given. Simulation experiment illustrates the effectiveness of this modified spectral DY conjugate gradient method.

A two-dimensional magnetic hybrid material based on intercalation of a cationic Prussian blue analog in montmorillonite nanoclay

NARCIS (Netherlands)

Gournis, Dimitrios; Papachristodoulou, Christina; Maccallini, Enrico; Rudolf, Petra; Karakassides, Michael A.; Karamanis, Dimitrios T.; Sage, Marie-Helene; Palstra, Thomas T. M.; Colomer, Jean-Francois; Papavasileiou, Konstantinos D.; Melissas, Vasilios S.; Gangas, Nicolaos H.

2010-01-01

A highly ordered two-dimensional hybrid magnetic nanocomposite has been prepared by synthesizing and intercalating a new cationic aluminum-hydroxy ferric ferrocyanide compound into a cation-adsorbing nanoclay (montmorillonite). Chemical and structural properties were investigated by X-ray

Spin-orbit coupling, electron transport and pairing instabilities in two-dimensional square structures

Energy Technology Data Exchange (ETDEWEB)

Kocharian, Armen N. [Department of Physics, California State University, Los Angeles, CA 90032 (United States); Fernando, Gayanath W.; Fang, Kun [Department of Physics, University of Connecticut, Storrs, Connecticut 06269 (United States); Palandage, Kalum [Department of Physics, Trinity College, Hartford, Connecticut 06106 (United States); Balatsky, Alexander V. [AlbaNova University Center Nordita, SE-106 91 Stockholm (Sweden)

2016-05-15

Rashba spin-orbit effects and electron correlations in the two-dimensional cylindrical lattices of square geometries are assessed using mesoscopic two-, three- and four-leg ladder structures. Here the electron transport properties are systematically calculated by including the spin-orbit coupling in tight binding and Hubbard models threaded by a magnetic flux. These results highlight important aspects of possible symmetry breaking mechanisms in square ladder geometries driven by the combined effect of a magnetic gauge field spin-orbit interaction and temperature. The observed persistent current, spin and charge polarizations in the presence of spin-orbit coupling are driven by separation of electron and hole charges and opposite spins in real-space. The modeled spin-flip processes on the pairing mechanism induced by the spin-orbit coupling in assembled nanostructures (as arrays of clusters) engineered in various two-dimensional multi-leg structures provide an ideal playground for understanding spatial charge and spin density inhomogeneities leading to electron pairing and spontaneous phase separation instabilities in unconventional superconductors. Such studies also fall under the scope of current challenging problems in superconductivity and magnetism, topological insulators and spin dependent transport associated with numerous interfaces and heterostructures.

Spin-orbit coupling, electron transport and pairing instabilities in two-dimensional square structures

Directory of Open Access Journals (Sweden)

Armen N. Kocharian

2016-05-01

Full Text Available Rashba spin-orbit effects and electron correlations in the two-dimensional cylindrical lattices of square geometries are assessed using mesoscopic two-, three- and four-leg ladder structures. Here the electron transport properties are systematically calculated by including the spin-orbit coupling in tight binding and Hubbard models threaded by a magnetic flux. These results highlight important aspects of possible symmetry breaking mechanisms in square ladder geometries driven by the combined effect of a magnetic gauge field spin-orbit interaction and temperature. The observed persistent current, spin and charge polarizations in the presence of spin-orbit coupling are driven by separation of electron and hole charges and opposite spins in real-space. The modeled spin-flip processes on the pairing mechanism induced by the spin-orbit coupling in assembled nanostructures (as arrays of clusters engineered in various two-dimensional multi-leg structures provide an ideal playground for understanding spatial charge and spin density inhomogeneities leading to electron pairing and spontaneous phase separation instabilities in unconventional superconductors. Such studies also fall under the scope of current challenging problems in superconductivity and magnetism, topological insulators and spin dependent transport associated with numerous interfaces and heterostructures.

Oblique ion-acoustic cnoidal waves in two temperature superthermal electrons magnetized plasma

International Nuclear Information System (INIS)

Panwar, A.; Ryu, C. M.; Bains, A. S.

2014-01-01

A study is presented for the oblique propagation of ion acoustic cnoidal waves in a magnetized plasma consisting of cold ions and two temperature superthermal electrons modelled by kappa-type distributions. Using the reductive perturbation method, the nonlinear Korteweg de-Vries equation is derived, which further gives the solutions with a special type of cnoidal elliptical functions. Both compressive and rarefactive structures are found for these cnoidal waves. Nonlinear periodic cnoidal waves are explained in terms of plasma parameters depicting the Sagdeev potential and the phase curves. It is found that the density ratio of hot electrons to ions μ significantly modifies compressive/refractive wave structures. Furthermore, the combined effects of superthermality of cold and hot electrons κ c ,κ h , cold to hot electron temperature ratio σ, angle of propagation and ion cyclotron frequency ω ci have been studied in detail to analyze the height and width of compressive/refractive cnoidal waves. The findings in the present study could have important implications in understanding the physics of electrostatic wave structures in the Saturn's magnetosphere where two temperature superthermal electrons are present

Complex dynamics in planar two-electron quantum dots

International Nuclear Information System (INIS)

Schroeter, Sebastian Josef Arthur

2013-01-01

Quantum dots play an important role in a wide range of recent experimental and technological developments. In particular they are promising candidates for realisations of quantum bits and further applications in quantum information theory. The harmonically confined Hooke's atom model is experimentally verified and separates in centre-of-mass and relative coordinates. Findings that are contradictory to this separability call for an extension of the model, in particular changing the confinement potential. In order to study effects of an anharmonic confinement potential on spectral properties of planar two-electron quantum dots a sophisticated numerical approach is developed. Comparison between the Helium atom, Hooke's atom and an anharmonic potential model are undertaken in order to improve the description of quantum dots. Classical and quantum features of complexity and chaos are investigated and used to characterise the dynamics of the system to be mixed regular-chaotic. Influence of decoherence can be described by quantum fidelity, which measures the effect of a perturbation on the time evolution. The quantum fidelity of eigenstates of the system depends strongly on the properties of the perturbation. Several methods for solving the time-dependent Schrödinger equation are implemented and a high level of accuracy for long time evolutions is achieved. The concept of offset entanglement, the entanglement of harmonic models in the noninteracting limit, is introduced. This concept explains different questions raised in the literature for harmonic quantum dot models, recently. It shows that only in the groundstate the electrons are not entangled in the fermionic sense. The applicability, validity, and origin of Hund's first rule in general quantum dot models is further addressed. In fact Hund's first rule is only applicable, and in this case also valid, for one pair of singlet and triplet states in Hooke's atom. For more realistic models of two-electron quantum dots an

Vibrationally inelastic electron scattering in a two-channel approximation

Czech Academy of Sciences Publication Activity Database

Čársky, Petr; Čurík, Roman

2008-01-01

Roč. 41, č. 5 (2008), , , 055203-1-6 ISSN 0953-4075 R&D Projects: GA AV ČR IAA100400501; GA AV ČR 1ET400400413; GA AV ČR KJB400400803; GA ČR GA202/08/0631; GA MŠk ME 857 Institutional research plan: CEZ:AV0Z40400503 Keywords : inelastic electron scattering * two-channel approximation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.089, year: 2008

Review of two-photon exchange in electron scattering

Energy Technology Data Exchange (ETDEWEB)

J. Arrington, P. G. Blunden, W. Melnitchouk

2011-10-01

We review the role of two-photon exchange (TPE) in electron-hadron scattering, focusing in particular on hadronic frameworks suitable for describing the low and moderate Q^2 region relevant to most experimental studies. We discuss the effects of TPE on the extraction of nucleon form factors and their role in the resolution of the proton electric to magnetic form factor ratio puzzle. The implications of TPE on various other observables, including neutron form factors, electroproduction of resonances and pions, and nuclear form factors, are summarized. Measurements seeking to directly identify TPE effects, such as through the angular dependence of polarization measurements, nonlinear epsilon contributions to the cross sections, and via e+p to e-p cross section ratios, are also outlined. In the weak sector, we describe the role of TPE and gamma-Z interference in parity-violating electron scattering, and assess their impact on the extraction of the strange form factors of the nucleon and the weak charge of the proton.

Effects of non-Maxwellian electron velocity distribution function on two-stream instability in low-pressure discharges

International Nuclear Information System (INIS)

Sydorenko, D.; Smolyakov, A.; Kaganovich, I.; Raitses, Y.

2007-01-01

Electron emission from discharge chamber walls is important for plasma maintenance in many low-pressure discharges. The electrons emitted from the walls are accelerated by the sheath electric field and are injected into the plasma as an electron beam. Penetration of this beam through the plasma is subject to the two-stream instability, which tends to slow down the beam electrons and heat the plasma electrons. In the present paper, a one-dimensional particle-in-cell code is used to simulate these effects both in a collisionless plasma slab with immobile ions and in a cross-field discharge of a Hall thruster. The two-stream instability occurs if the total electron velocity distribution function of the plasma-beam system is a nonmonotonic function of electron speed. Low-pressure plasmas can be depleted of electrons with energy above the plasma potential. This study reveals that under such conditions the two-stream instability depends crucially on the velocity distribution function of electron emission. It is shown that propagation of the secondary electron beams in Hall thrusters may be free of the two-stream instability if the velocity distribution of secondary electron emission is a monotonically decaying function of speed. In this case, the beams propagate between the walls with minimal loss of the beam current and the secondary electron emission does not affect the thruster plasma properties

Stable biexcitons in two-dimensional metal-halide perovskites with strong dynamic lattice disorder

Science.gov (United States)

Thouin, Félix; Neutzner, Stefanie; Cortecchia, Daniele; Dragomir, Vlad Alexandru; Soci, Cesare; Salim, Teddy; Lam, Yeng Ming; Leonelli, Richard; Petrozza, Annamaria; Kandada, Ajay Ram Srimath; Silva, Carlos

2018-03-01

With strongly bound and stable excitons at room temperature, single-layer, two-dimensional organic-inorganic hybrid perovskites are viable semiconductors for light-emitting quantum optoelectronics applications. In such a technological context, it is imperative to comprehensively explore all the factors—chemical, electronic, and structural—that govern strong multiexciton correlations. Here, by means of two-dimensional coherent spectroscopy, we examine excitonic many-body effects in pure, single-layer (PEA) 2PbI4 (PEA = phenylethylammonium). We determine the binding energy of biexcitons—correlated two-electron, two-hole quasiparticles—to be 44 ±5 meV at room temperature. The extraordinarily high values are similar to those reported in other strongly excitonic two-dimensional materials such as transition-metal dichalcogenides. Importantly, we show that this binding energy increases by ˜25 % upon cooling to 5 K. Our work highlights the importance of multiexciton correlations in this class of technologically promising, solution-processable materials, in spite of the strong effects of lattice fluctuations and dynamic disorder.

Relations of secondary electron emission to microdosimetry and applications to two-target theory

International Nuclear Information System (INIS)

Forsberg, B.J.; Burlin, T.E.

1978-01-01

Secondary electron emission has been suggested as a phenomenon that offers considerable potential for microdosimetric studies (Burlin, 1973). This potential is examined further through a theoretical study. Previous work on the stochastic nature of secondary electron emission is reviewed and in particular a Monte Carlo programme of McDonald, Lamki and Delaney (1971, 1973) is developed. Lineal energy distributions are presented for tissue equivalent volumes of about 5nm in three materials for different electron energies. The dose mean of lineal energy and the frequency mean of lineal energy are calculated and these results for volumes with linear dimension of a few nanometers are compared with results of Bengtsson and Lindborg (1974), Braby and Ellett (1971) and Dvorak (1975). Several authors have suggested that some radiobiological effects may result from energy deposition in two different targets. An experimental investigation using proportional counter measurements to simulate two-target theory has been reported. In this paper an alternative technique to twin-proportional counter measurements, based on the secondary electron emission from the two sides of a thin foil is discussed. The extended version of the programme calculates the coincident P(nsub(i),nsub(e)) distribution, that is the number of secondary electrons pair (nsub(i), nsub(e)) is recorded, where nsub(i) is the number of secondary electrons leaving the incident side and nsub(e) is leaving the exit side of the foil simultaneously

Hybrid upwind discretization of nonlinear two-phase flow with gravity

Science.gov (United States)

Lee, S. H.; Efendiev, Y.; Tchelepi, H. A.

2015-08-01

Multiphase flow in porous media is described by coupled nonlinear mass conservation laws. For immiscible Darcy flow of multiple fluid phases, whereby capillary effects are negligible, the transport equations in the presence of viscous and buoyancy forces are highly nonlinear and hyperbolic. Numerical simulation of multiphase flow processes in heterogeneous formations requires the development of discretization and solution schemes that are able to handle the complex nonlinear dynamics, especially of the saturation evolution, in a reliable and computationally efficient manner. In reservoir simulation practice, single-point upwinding of the flux across an interface between two control volumes (cells) is performed for each fluid phase, whereby the upstream direction is based on the gradient of the phase-potential (pressure plus gravity head). This upwinding scheme, which we refer to as Phase-Potential Upwinding (PPU), is combined with implicit (backward-Euler) time discretization to obtain a Fully Implicit Method (FIM). Even though FIM suffers from numerical dispersion effects, it is widely used in practice. This is because of its unconditional stability and because it yields conservative, monotone numerical solutions. However, FIM is not unconditionally convergent. The convergence difficulties are particularly pronounced when the different immiscible fluid phases switch between co-current and counter-current states as a function of time, or (Newton) iteration. Whether the multiphase flow across an interface (between two control-volumes) is co-current, or counter-current, depends on the local balance between the viscous and buoyancy forces, and how the balance evolves in time. The sensitivity of PPU to small changes in the (local) pressure distribution exacerbates the problem. The common strategy to deal with these difficulties is to cut the timestep and try again. Here, we propose a Hybrid-Upwinding (HU) scheme for the phase fluxes, then HU is combined with implicit

Electrostatic electron spectrometer based on two cylinders without axial symmetry

International Nuclear Information System (INIS)

Varga, D.; Toekesi, K.

2005-01-01

Complete text of publication follows. During the last decades electrostatic analyzers were widely used in atomic and surface physics. This was due to their good focusing and dispersion properties, The cylindrical mirror analyzer (CMA) is one of the most advantageous electrostatic analyzers. Its second order focusing properties have been calculated by many authors. A modified, so called 'box' type, CMA (ESA-13) is described in ref. [1]. For CMA (ESA-13), the position of the electron source and focus are outside the analyzer which is desirable for practical reasons. The ends of the cylinders are closed with two coaxial discs, therefore the electrostatic field near the edge is distorted compared to the logarithmic field existing in the classical 'in-finite' cylindrical mirror analyzer. However, the 'box' type distorted field cylindrical mirror analyzer geometry contains several limitations regarding the irradiation of the sample. Therefore, the construction of these analyzers was changed by replacing the endings of the analyzer with conically shaped electrodes ensuring a better accessibility for excitation. But among the various experimental tasks many geometrical conditions arise that are different or that need different sizes compared with the previous ones. Therefore, in a practical point of view, it is extremely advantageous to have different variations of spectrometers. This allows us to choose the best solution for a given problem. In this work, we present electron-optical properties of a mirror type electrostatic electron spectrometer consisting of two cylinders with eccentricity (see Fig 1.), namely the Eccentric Cylindrical Mirror Analyzer (ECMA). The designed analyzer is a possible variation of CMA for measuring the energy distribution of electrons with high energy resolution or making an electron monocromator. It has been shown that the Eccentric Cylindrical Mirror Analyzer has second-order focusing properties with remarkable dispersion (see Fig 2

Electron Microscopy Center (EMC)

Data.gov (United States)

Federal Laboratory Consortium — The Electron Microscopy Center (EMC) at Argonne National Laboratory develops and maintains unique capabilities for electron beam characterization and applies those...

Effect of impurities on the two-dimensional electron gas polarizability

International Nuclear Information System (INIS)

Nkoma, J.S.

1980-06-01

The polarizability for a two-dimensional electron gas is calculated in the presence of impurities by a Green function formalism. This leads to a system with finite mean free path due to electrons scattering off impurities. The calculated polarizability is found to be strongly dependent on the mean free path. The main feature is the suppression of the sharp corner at wave vector 2ksub(F) for finite mean free paths, and the pure metal result is recovered for the infinite mean free path. A possible application of the results to the transport properties of semiconductor inversion layers is discussed. (author)

Pilot-scale comparison of two hybrid-passive landfill leachate treatment systems operated in a cold climate.

Science.gov (United States)

Speer, Sean; Champagne, Pascale; Anderson, Bruce

2012-01-01

Hybrid-passive landfill leachate treatment systems employ active pretreatment to remove dissolved inorganic constituents and decrease the oxygen demand of the leachate prior to treatment in a passive system. In a 1-year pilot-scale study, two passive treatment systems - a peat and wood shaving biological trickle filter and a sand and gravel constructed wetland - were installed to treat leachate from the Merrick Landfill in North Bay, Ontario, Canada. Leachate was pretreated in a fixed-film aerobic reactor, which provided reductions in COD (26%), and masses of ammonia (21%), Al (69%), Ca (57%), Fe (73%) and Sr (37%). A comparison of the performance of the hybrid-passive treatment systems indicated different extents of heterotrophic nitrification; the peat and wood shaving filter removed 49% of the ammonia and nitrified 29%, while the constructed wetland removed 99% of the ammonia and nitrified 90%. Hybrid-passive landfill leachate treatment was determined to be feasible in cold climates. Copyright © 2011 Elsevier Ltd. All rights reserved.

High-power free-electron laser amplifier using a scalloped electron beam and a two-stage wiggler

Directory of Open Access Journals (Sweden)

D. C. Nguyen

2006-05-01

Full Text Available High-power free-electron laser (FEL amplifiers present many practical design and construction problems. One such problem is possible damage to any optical beam control elements beyond the wiggler. The ability to increase the optical beam’s divergence angle after the wiggler, thereby reducing the intensity on the first optical element, is important to minimize such damage. One proposal to accomplish this optical beam spreading is to pinch the electron beam thereby focusing the radiation as well. In this paper, we analyze an approach that relies on the natural betatron motion to pinch the electron beam near the end of the wiggler. We also consider a step-tapered, two-stage wiggler to enhance the efficiency. The combination of a pinched electron beam and step-taper wiggler leads to additional optical guiding of the optical beam. This novel configuration is studied in simulation using the MEDUSA code. For a representative set of beam and wiggler parameters, we discuss (i the effect of the scalloped beam on the interaction in the FEL and on the focusing and propagation of the radiation, and (ii the efficiency enhancement in the two-stage wiggler.

Dependence of synergy current driven by lower hybrid wave and electron cyclotron wave on the frequency and parallel refractive index of electron cyclotron wave for Tokamaks

International Nuclear Information System (INIS)

Huang, J.; Chen, S. Y.; Tang, C. J.

2014-01-01

The physical mechanism of the synergy current driven by lower hybrid wave (LHW) and electron cyclotron wave (ECW) in tokamaks is investigated using theoretical analysis and simulation methods in the present paper. Research shows that the synergy relationship between the two waves in velocity space strongly depends on the frequency ω and parallel refractive index N // of ECW. For a given spectrum of LHW, the parameter range of ECW, in which the synergy current exists, can be predicted by theoretical analysis, and these results are consistent with the simulation results. It is shown that the synergy effect is mainly caused by the electrons accelerated by both ECW and LHW, and the acceleration of these electrons requires that there is overlap of the resonance regions of the two waves in velocity space

Are we ready to test QED in two-electron ions

International Nuclear Information System (INIS)

Ermolaev, A.M.

1981-01-01

The great improvement on the accuracy of the measured transition intervals in two-electron ions achieved recently is discussed with reference to reports of Berry (ANL) and Silver (Oxford) on the precision determination of the 2s 3 S 1 - 2p 3 P/sub J/, J = 0, and 2, intervals in the ions with intermediate Z

Nonlocality, Correlations, and Magnetotransport in a Spatially Modulated Two-Dimensional Electron Gas

Science.gov (United States)

Raichev, O. E.

2018-04-01

It is shown that the classical commensurability phenomena in weakly modulated two-dimensional electron systems is a manifestation of the intrinsic properties of the correlation functions describing a homogeneous electron gas in a magnetic field. The theory demonstrates the importance for consideration of nonlocal response and removes the gap between classical and quantum approaches to magnetotransport in such systems.

Band Alignment Determination of Two-Dimensional Heterojunctions and Their Electronic Applications

KAUST Repository

Chiu, Ming-Hui

2018-01-01

Two-dimensional (2D) layered materials such as MoS2 have been recognized as high on-off ratio semiconductors which are promising candidates for electronic and optoelectronic devices. In addition to the use of individual 2D materials, the accelerated

Experiments on melting in classical and quantum two dimensional electron systems

International Nuclear Information System (INIS)

Williams, F.I.B.

1991-01-01

''Two dimensional electron system'' (2DES) here refers to electrons whose dynamics is free in 2 dimensions but blocked in the third. Experiments have been performed in two limiting situations: the classical, low density, limit realised by electrons deposited on a liquid helium surface and the quantum, high density, limit realised by electrons at an interface between two epitaxially matched semiconductors. In the classical system, where T Q c so that the thermodynamic state is determined by the competition between the temperature and the Coulomb interaction, melting is induced either by raising the temperature at constant density or by lowering the density at finite temperature. In the quantum system, it is not possible to lower the density below about 100n W without the Coulomb interaction losing out to the random field representing the extrinsic disorder imposed by the semiconductor host. Instead one has to induce crystallisation with the help of the Lorentz force, by applying a perpendicular magnetic field B [2] . As the quantum magnetic length l c = (Planck constant c/eB) 1/2 is reduced with respect to the interelectronic spacing a, expressed by the filling factor ν 2l c 2 /a 2 , the system exhibits the quantum Hall effect (QHE), first for integer then for fractional values of ν. The fractional quantum Hall effect (FQHE) is a result of Coulomb induced correlation in the quantum liquid, but as ν is decreased still further the correlations are expected to take on long-range crystal-like periodicity accompanied by elastic shear rigidity. Such a state can nonetheless be destroyed by the disordering effect of temperature, giving rise to a phase boundary in a (T, B) plane. The aim of experiment is first to determine the phase diagram and then to help elucidate the mechanism of the melting. (author)

Hybrid-dimensional modelling of two-phase flow through fractured porous media with enhanced matrix fracture transmission conditions

Science.gov (United States)

Brenner, Konstantin; Hennicker, Julian; Masson, Roland; Samier, Pierre

2018-03-01

In this work, we extend, to two-phase flow, the single-phase Darcy flow model proposed in [26], [12] in which the (d - 1)-dimensional flow in the fractures is coupled with the d-dimensional flow in the matrix. Three types of so called hybrid-dimensional two-phase Darcy flow models are proposed. They all account for fractures acting either as drains or as barriers, since they allow pressure jumps at the matrix-fracture interfaces. The models also permit to treat gravity dominated flow as well as discontinuous capillary pressure at the material interfaces. The three models differ by their transmission conditions at matrix fracture interfaces: while the first model accounts for the nonlinear two-phase Darcy flux conservations, the second and third ones are based on the linear single phase Darcy flux conservations combined with different approximations of the mobilities. We adapt the Vertex Approximate Gradient (VAG) scheme to this problem, in order to account for anisotropy and heterogeneity aspects as well as for applicability on general meshes. Several test cases are presented to compare our hybrid-dimensional models to the generic equi-dimensional model, in which fractures have the same dimension as the matrix, leading to deep insight about the quality of the proposed reduced models.

Removal Natural Organic Matter (NOM in Peat Water from Wetland Area by Coagulation-Ultrafiltration Hybrid Process with Pretreatment Two-Stage Coagulation

Directory of Open Access Journals (Sweden)

Mahmud Mahmud

2016-06-01

Full Text Available The primary problem encountered in the application of membrane technology was membrane fouling. During this time, hybrid process by coagulation-ultrafiltration in drinking water treatment that has been conducted by some research, using by one-stage coagulation. The goal of this research was to investigate the effect of two-stage coagulation as a pretreatment towards performance of the coagulation-ultrafiltration hybrid process for removal NOM in the peat water. Coagulation process, either with the one-stage or two-stage coagulation was very good in removing charge hydrophilic fraction, i.e. more than 98%. NOM fractions of the peat water, from the most easily removed by the two-stage coagulation and one-stage coagulation process was charged hydrophilic>strongly hydrophobic>weakly hydrophobic>neutral hydrophilic. The two-stage coagulation process could removed UV254 and colors with a little better than the one-stage coagulation at the optimum coagulant dose. Neutral hydrophilic fraction of peat water NOM was the most influential fraction of UF membrane fouling. The two-stage coagulation process better in removing the neutral hidrophilic fraction, while removing of the charged hydrophilic, strongly hydrophobic and weakly hydrophobic similar to the one-stage coagulation. Hybrid process by pretreatment with two-stage coagulation, beside can increased removal efficiency of UV254 and color, also can reduced fouling rate of the ultrafiltration membraneIt must not exceed 250 words, contains a brief summary of the text, covering the whole manuscript without being too elaborate on every section. Avoid any abbreviation, unless it is a common knowledge or has been previously stated.

Removal Natural Organic Matter (NOM in Peat Water from Wetland Area by Coagulation-Ultrafiltration Hybrid Process with Pretreatment Two-Stage Coagulation

Directory of Open Access Journals (Sweden)

Mahmud Mahmud

2013-11-01

Full Text Available The primary problem encountered in the application of membrane technology was membrane fouling. During this time, hybrid process by coagulation-ultrafiltration in drinking water treatment that has been conducted by some research, using by one-stage coagulation. The goal of this research was to investigate the effect of two-stage coagulation as a pretreatment towards performance of the coagulation-ultrafiltration hybrid process for removal NOM in the peat water. Coagulation process, either with the one-stage or two-stage coagulation was very good in removing charge hydrophilic fraction, i.e. more than 98%. NOM fractions of the peat water, from the most easily removed by the two-stage coagulation and one-stage coagulation process was charged hydrophilic>strongly hydrophobic>weakly hydrophobic>neutral hydrophilic. The two-stage coagulation process could removed UV254 and colors with a little better than the one-stage coagulation at the optimum coagulant dose. Neutral hydrophilic fraction of peat water NOM was the most influential fraction of UF membrane fouling. The two-stage coagulation process better in removing the neutral hidrophilic fraction, while removing of the charged hydrophilic, strongly hydrophobic and weakly hydrophobic similar to the one-stage coagulation. Hybrid process by pretreatment with two-stage coagulation, beside can increased removal efficiency of UV254 and color, also can reduced fouling rate of the ultrafiltration membraneIt must not exceed 250 words, contains a brief summary of the text, covering the whole manuscript without being too elaborate on every section. Avoid any abbreviation, unless it is a common knowledge or has been previously stated.

Overscreening-underscreening transition in the two-channel Kondo model induced by electron-electron repulsion

International Nuclear Information System (INIS)

Zhang Yumei; Chen Hong.

1995-09-01

The effects of the repulsion between the electrons on the two-channel Kondo problem are studied by use of the bosonization technique. Following Emery and Kivelson, we define a special case in the spin density wave sector, in which the impurity spin is actually detached from the dynamics of the electrons. The model is thus mapped to a local Sine-Gordon system. For weak repulsion, the basic features of the overscreening picture are maintained. However, at sufficient strong repulsion the system is driven into the weak coupling regime, hence an overscreening-underscreening transition emerges. (author). 22 refs

Natural hybridization and reproductive isolation between two Primula speciesFA

Institute of Scientific and Technical Information of China (English)

Yanping Xie; Xingfu Zhu; Yongpeng Ma; Jianli Zhao; Li Li; Qingjun Li

2017-01-01

Natural hybridization frequently occurs in plants and can facilitate gene flow between species,possibly resulting in species refusion.However,various reproductive barriers block the formation of hybrids and maintain species integrity.Here,we conducted a field survey to examine natural hybridization and reproductive isolation (RI) between sympatric populations of Primula secundiflora and P.poissonii using ten nuclear simple sequence repeat (SSR) loci.Although introgressive hybridization occurred,species boundaries between P.secundiflora and P.poissonii were maintained through nearly complete reproductive isolation.These interfertile species provide an excellent model for studying the RI mechanisms and evolutionary forces that maintain species boundaries.

Anomalous electron doping independent two-dimensional superconductivity

Science.gov (United States)

Zhou, Wei; Xing, Xiangzhuo; Zhao, Haijun; Feng, Jiajia; Pan, Yongqiang; Zhou, Nan; Zhang, Yufeng; Qian, Bin; Shi, Zhixiang

2017-07-01

Transition metal (Co and Ni) co-doping effects are investigated on an underdoped Ca0.94La0.06Fe2As2 compound. It is discovered that electron doping from substituting Fe with transition metal (TM = Co, Ni) can trigger high-{T}{{c}} superconductivity around 35 K, which emerges abruptly before the total suppression of the innate spin-density-wave/anti-ferromagnetism (SDW/AFM) state. Remarkably, the critical temperature for the high-{T}{{c}} superconductivity remains constant against a wide range of TM doping levels. And the net electron doping density dependence of the superconducting {T}{{c}} based on the rigid band model can be nicely scaled into a single curve for Co and Ni substitutions, in stark contrast to the case of Ba(Fe1-x TM x )2As2. This carrier density independent superconductivity and the unusual scaling behavior are presumably resulted from the interface superconductivity based on the similarity with the interface superconductivity in a La2-x Sr x CuO4-La2CuO4 bilayer. Evidence of the two-dimensional character of the superfluid by angle-resolved magneto-resistance measurements can further strengthen the interface nature of the high-{T}{{c}} superconductivity.

Pauli-spin blockade in a vertical double quantum dot holding two to five electrons

International Nuclear Information System (INIS)

Kodera, T; Arakawa, Y; Tarucha, S; Ono, K; Amaha, S

2009-01-01

We use a vertical double quantum dot (QD) to study spin blockade (SB) for the two-to five-electron states. SB observed for the two- and four-electron states is both assigned to Pauli exclusion with formation of a spin triplet state, and lifted by singlet-triplet admixing due to fluctuating nuclear field. SB observed for the five-electron state is caused by combined Pauli effect and Hund's rule. We observe a hysteretic behavior of the SB leakage current for up and down sweep of magnetic field, and argue that SB and its lifting by hyperfine interaction are subtle with the spin configuration and modified depending on the inter-dot detuning and number of electrons.

Experimental demonstration of synergy between electron cyclotron and lower hybrid current drive on Tore Supra

International Nuclear Information System (INIS)

Artaud, J.F.; Giruzzi, G.; Dumont, R.J.; Imbeaux, F.; Bibet, P.; Bouquey, F.; Clary, J.; Ekedahl, A.; Hoang, G.T.; Lennholm, M.; Magne, R.; Segui, J.L.

2004-01-01

Non-inductive current drive (CD) has two main applications in tokamaks: sustainment of a substantial fraction of the toroidal plasma current necessary for the plasma confinement and control of the plasma stability and transport properties by appropriate shaping of the current density profile. For the first kind of applications, lower hybrid (LH) waves are known to provide the highest efficiency (defined as the ratio of the driven current to the injected wave power), although with limited control capability. Conversely, electron cyclotron (EC) waves drive highly localized currents, and are therefore particularly suited for control purposes, but their CD efficiency is much lower than that of LH waves (typically, an order of magnitude in present day experiments). Various calculations have demonstrated an interesting property: the current driven by the simultaneous use of the two waves, I(LH+EC), can be significantly larger than the sum I(LH)+I(EC) of the currents separately driven by the two waves in the same plasma conditions. This property, called synergy effect. The peculiar experimental conditions attainable on the Tore Supra tokamak have allowed the first experimental demonstration of the synergy between EC and LH current drive. The significant improvement of the electron cyclotron current drive (ECCD) efficiency in the presence of low hybrid current drive (LHCD), predicted by kinetic theory and confirmed by stationary experiments on Tore Supra, opens up the possibility of using ECCD as an efficient current profile control tool in LHCD plasmas

The Economic Potential of Two Nuclear-Renewable Hybrid Energy Systems

Energy Technology Data Exchange (ETDEWEB)

Ruth, Mark [National Renewable Energy Lab. (NREL), Golden, CO (United States); Cutler, Dylan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Flores-Espino, Francisco [National Renewable Energy Lab. (NREL), Golden, CO (United States); Stark, Greg [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jenkin, Thomas [National Renewable Energy Lab. (NREL), Golden, CO (United States); Simpkins, Travis [National Renewable Energy Lab. (NREL), Golden, CO (United States); Macknick, Jordan [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-08-01

Tightly coupled nuclear-renewable hybrid energy systems (N-R HESs) are an option that can generate zero-carbon, dispatchable electricity and provide zero-carbon energy for industrial processes at a lower cost than alternatives. N-R HESs are defined as systems that are managed by a single entity and link a nuclear reactor that generates heat, a thermal power cycle for heat to electricity conversion, at least one renewable energy source, and an industrial process that uses thermal and/or electrical energy. This report provides results of an analysis of two N-R HES scenarios. The first is a Texas-synthetic gasoline scenario that includes four subsystems: a nuclear reactor, thermal power cycle, wind power plant, and synthetic gasoline production technology. The second is an Arizona-desalination scenario with its four subsystems a nuclear reactor, thermal power cycle, solar photovoltaics, and a desalination plant. The analysis focuses on the economics of the N-R HESs and how they compare to other options, including configurations without all the subsystems in each N-R HES and alternatives where the energy is provided by natural gas.

Performance comparison of two low-CO2 emission solar/methanol hybrid combined cycle power systems

International Nuclear Information System (INIS)

Li, Yuanyuan; Zhang, Na; Lior, Noam

2015-01-01

Highlights: • Two novel solar hybrid combined cycle systems have been proposed and analyzed. • The power systems integrate solar-driven thermo-chemical conversion and CO 2 capture. • Exergy efficiency of about 55% and specific CO 2 emissions of 34 g/kW h are predicted. • Systems CO 2 emissions are 36.8% lower compared to a combined cycle with CO 2 capture. • The fossil fuel demand is ∼30% lower with a solar share of ∼20%. - Abstract: Two novel hybrid combined cycle power systems that use solar heat and methanol, and integrate CO 2 capture, are proposed and analyzed, one based on solar-driven methanol decomposition and the other on solar-driven methanol reforming. The high methanol conversion rates at relatively low temperatures offer the advantage of using the solar heat at only 200–300 °C to drive the syngas production by endothermic methanol conversions and its conversion to chemical energy. Pre-combustion decarbonization is employed to produce CO 2 -free fuel from the fully converted syngas, which is then burned to produce heat at the high temperature for power generation in the proposed advanced combined cycle systems. To improve efficiency, the systems’ configurations were based on the principle of cascade use of multiple heat sources of different temperatures. The thermodynamic performance of the hybrid power systems at its design point is simulated and evaluated. The results show that the hybrid systems can attain an exergy efficiency of about 55%, and specific CO 2 emissions as low as 34 g/kW h. Compared to a gas/steam combined cycle with flue gas CO 2 capture, the proposed solar-assisted system CO 2 emissions are 36.8% lower, and a fossil fuel saving ratio of ∼30% is achievable with a solar thermal share of ∼20%. The system integration predicts high efficiency conversion of solar heat and low-energy-penalty CO 2 capture, with the additional advantage that solar heat is at relatively low temperature where its collection is cheaper and

Resonant spin Hall effect in two dimensional electron gas

Science.gov (United States)

Shen, Shun-Qing

2005-03-01

Remarkable phenomena have been observed in 2DEG over last two decades, most notably, the discovery of integer and fractional quantum Hall effect. The study of spin transport provides a good opportunity to explore spin physics in two-dimensional electron gas (2DEG) with spin-orbit coupling and other interaction. It is already known that the spin-orbit coupling leads to a zero-field spin splitting, and competes with the Zeeman spin splitting if the system is subjected to a magnetic field perpendicular to the plane of 2DEG. The result can be detected as beating of the Shubnikov-de Haas oscillation. Very recently the speaker and his collaborators studied transport properties of a two-dimensional electron system with Rashba spin-orbit coupling in a perpendicular magnetic field. The spin-orbit coupling competes with the Zeeman splitting to generate additional degeneracies between different Landau levels at certain magnetic fields. It is predicted theoretically that this degeneracy, if occurring at the Fermi level, gives rise to a resonant spin Hall conductance, whose height is divergent as 1/T and whose weight is divergent as -lnT at low temperatures. The charge Hall conductance changes by 2e^2/h instead of e^2/h as the magnetic field changes through the resonant point. The speaker will address the resonance condition, symmetries in the spin-orbit coupling, the singularity of magnetic susceptibility, nonlinear electric field effect, the edge effect and the disorder effect due to impurities. This work was supported by the Research Grants Council of Hong Kong under Grant No.: HKU 7088/01P. *S. Q. Shen, M. Ma, X. C. Xie, and F. C. Zhang, Phys. Rev. Lett. 92, 256603 (2004) *S. Q. Shen, Y. J. Bao, M. Ma, X. C. Xie, and F. C. Zhang, cond-mat/0410169

Two molecular markers based on mitochondrial genomes for varieties identification of the northern snakehead (Channa argus) and blotched snakehead (Channa maculata) and their reciprocal hybrids.

Science.gov (United States)

Xincheng, Zhang; Kunci, Chen; Xinping, Zhu; Jian, Zhao; Qing, Luo; Xiaoyou, Hong; Wei, Li; Fengfang, Xiao

2015-08-01

The northern snakehead (Channa argus) and blotched snakehead (Channa maculata) and their reciprocal hybrids have played important roles in the Chinese freshwater aquaculture industry, with an annual production in China exceeding 400 thousand tons. While these are popular aquaculture breeds in China, it is not easy to identify northern snakehead, blotched snakehead, and their hybrids. Thus, a method should be developed to identify these varieties. To distinguish between the reciprocal hybrids (C. argus ♀ × C. maculata ♂ and C. maculata ♀ × C. argus ♂), the mitochondrial genome sequences of northern snakehead and blotched snakehead and their reciprocal hybrids were compared. Following the alignment and analysis of mtDNA sequences of northern snakehead, blotched snakehead and their hybrids, two pairs of specific primers were designed based on identified differences ranging from 12S rRNA to 16S rRNA gene. The BY1 primers amplified the same bands in the blotched snakehead and the hybrid (C. maculata ♀ × C. argus ♂), while producing no products in northern snakehead and the hybrid (C. argus ♀ × C. maculata ♂). Amplification with WY1 yielded the opposite results. Then, 30 individuals per fish were randomized to verify the primers, and the results showed that the primers were specific for breeds, as intended. The specific primers can not only simply distinguish between two kinds of hybrids, but also rapidly identify the two parents. This study provides a method of molecular marker identification to identify reciprocal hybrids.

Hybrid origin of Asian aspermic Fasciola flukes is confirmed by analyzing two single-copy genes, pepck and pold

Science.gov (United States)

HAYASHI, Kei; ICHIKAWA-SEKI, Madoka; MOHANTA, Uday Kumar; SHORIKI, Takuya; CHAICHANASAK, Pannigan; ITAGAKI, Tadashi

2017-01-01

Nuclear gene markers, phosphoenolpyruvate carboxykinase (pepck) and DNA polymerase delta (pold), have been developed for precise discrimination of Fasciola flukes instead of internal transcribed spacer 1. In this study, these two genes of 730 Fasciola flukes from eight Asian countries were analyzed. The results were compared with their mitochondrial NADH dehydrogenase subunit 1 (nad1) lineages for obtaining a definitive evidence of the hybrid origin of aspermic Fasciola flukes. All the flukes categorized into the aspermic nad1 lineages possessed both the fragment patterns of F. hepatica and F. gigantica (mixed types) in pepck and/or pold. These findings provide clear evidence for the hybrid origin of aspermic Fasciola lineages and suggest that “aspermic Fasciola flukes” should hereafter be called “hybrid Fasciola flukes”. PMID:29187710

DFT and two-dimensional correlation analysis methods for evaluating the Pu{sup 3+}–Pu{sup 4+} electronic transition of plutonium-doped zircon

Energy Technology Data Exchange (ETDEWEB)

Bian, Liang, E-mail: bianliang@ms.xjb.ac.cn [Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011, Xinjiang (China); Laboratory for Extreme Conditions Matter Properties, South West University of Science and Technology, Mianyang 621010, Sichuan (China); Dong, Fa-qin; Song, Mian-xin [Laboratory for Extreme Conditions Matter Properties, South West University of Science and Technology, Mianyang 621010, Sichuan (China); Dong, Hai-liang [Department of Geology and Environmental Earth Science, Miami University, Oxford, OH 45056 (United States); Li, Wei-Min [Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011, Xinjiang (China); Duan, Tao; Xu, Jin-bao [Laboratory for Extreme Conditions Matter Properties, South West University of Science and Technology, Mianyang 621010, Sichuan (China); Zhang, Xiao-yan [Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011, Xinjiang (China); Laboratory for Extreme Conditions Matter Properties, South West University of Science and Technology, Mianyang 621010, Sichuan (China)

2015-08-30

Highlights: • Effect of Pu f-shell electron on the electronic property of zircon is calculated via DFT and 2D-CA techniques. • Reasons of Pu f-shell electron influencing on electronic properties are systematically discussed. • Phase transitions are found at two point 2.8 mol% and 7.5 mol%. - Abstract: Understanding how plutonium (Pu) doping affects the crystalline zircon structure is very important for risk management. However, so far, there have been only a very limited number of reports of the quantitative simulation of the effects of the Pu charge and concentration on the phase transition. In this study, we used density functional theory (DFT), virtual crystal approximation (VCA), and two-dimensional correlation analysis (2D-CA) techniques to calculate the origins of the structural and electronic transitions of Zr{sub 1−c}Pu{sub c}SiO{sub 4} over a wide range of Pu doping concentrations (c = 0–10 mol%). The calculations indicated that the low-angular-momentum Pu-f{sub xy}-shell electron excites an inner-shell O-2s{sup 2} orbital to create an oxygen defect (V{sub O-s}) below c = 2.8 mol%. This oxygen defect then captures a low-angular-momentum Zr-5p{sup 6}5s{sup 2} electron to form an sp hybrid orbital, which exhibits a stable phase structure. When c > 2.8 mol%, each accumulated V{sub O-p} defect captures a high-angular-momentum Zr-4d{sub z} electron and two Si-p{sub z} electrons to create delocalized Si{sup 4+} → Si{sup 2+} charge disproportionation. Therefore, we suggest that the optimal amount of Pu cannot exceed 7.5 mol% because of the formation of a mixture of ZrO{sub 8} polyhedral and SiO{sub 4} tetrahedral phases with the orientation (10-1). This study offers new perspective on the development of highly stable zircon-based solid solution materials.

A Chip-Capillary Hybrid Device for Automated Transfer of Sample Pre-Separated by Capillary Isoelectric Focusing to Parallel Capillary Gel Electrophoresis for Two-Dimensional Protein Separation

Science.gov (United States)

Lu, Joann J.; Wang, Shili; Li, Guanbin; Wang, Wei; Pu, Qiaosheng; Liu, Shaorong

2012-01-01

In this report, we introduce a chip-capillary hybrid device to integrate capillary isoelectric focusing (CIEF) with parallel capillary sodium dodecyl sulfate – polyacrylamide gel electrophoresis (SDS-PAGE) or capillary gel electrophoresis (CGE) toward automating two-dimensional (2D) protein separations. The hybrid device consists of three chips that are butted together. The middle chip can be moved between two positions to re-route the fluidic paths, which enables the performance of CIEF and injection of proteins partially resolved by CIEF to CGE capillaries for parallel CGE separations in a continuous and automated fashion. Capillaries are attached to the other two chips to facilitate CIEF and CGE separations and to extend the effective lengths of CGE columns. Specifically, we illustrate the working principle of the hybrid device, develop protocols for producing and preparing the hybrid device, and demonstrate the feasibility of using this hybrid device for automated injection of CIEF-separated sample to parallel CGE for 2D protein separations. Potentials and problems associated with the hybrid device are also discussed. PMID:22830584

A shift in nuclear state as the result of natural interspecific hybridization between two North American taxa of the basidiomycete complex Heterobasidion

Science.gov (United States)

Matteo Garbelotto; Paolo Gonthier; Rachel Linzer; Giovanni Nicolotti; William Otrosina

2004-01-01

A natural first generation hybrid fungus shows interspecific heterozygosity. The nuclear condition of a rare natural hybrid between two taxa of the Heterobasidion complex is investigated. Heterobasidion species are known to be either homokaryotic (haploid) or heterokaryotic (n + n), but heterokaryons are made up of both...

Multichromophoric hybrid species made of perylene bisimide derivatives and Ru(ii) and Os(ii) polypyridine subunits.

Science.gov (United States)

Nastasi, Francesco; La Ganga, Giuseppina; Campagna, Sebastiano; Syrgiannis, Zois; Rigodanza, Francesco; Vitale, Stefania; Licciardello, Antonino; Prato, Maurizio

2017-05-31

Herein, the synthesis and the photophysical and redox properties of a new perylene bisimide (PBI) species (L), bearing two 1,10-phenanthroline (phen) ligands at the two imide positions of the PBI, and its dinuclear Ru(ii) and Os(ii) complexes, [(bpy) 2 Ru(μ-L)Ru(bpy) 2 ](PF 6 ) 4 (Ru2; bpy = 2,2'-bipyridine) and [(Me 2 -bpy) 2 Os(μ-L)Os(Me 2 -bpy) 2 ](PF 6 ) 4 (Os2; Me 2 -bpy = (4,4'-dimethyl)-2,2'-bipyridine), are reported. The absorption spectra of the compounds are dominated by the structured bands of the PBI subunit due to the lowest-energy spin-allowed π-π* transition. The spin-allowed MLCT transitions in Ru2 and Os2 are inferred by the absorption at 350-470 nm, where the PBI absorption is negligible. The absorption band extends towards the red region for Os2 due to the spin-forbidden MLCT transitions, intensified by the heavy osmium center. The reduction processes of the compounds are dominated by two successive mono-electronic PBI-based processes, which in the metal complexes are slightly shifted compared to the free ligand. On oxidation, both metal complexes undergo an apparent bi-electronic process (at 1.31 V vs. SCE for Ru2 and 0.77 V for Os2), attributed to the simultaneous one-electron oxidation of the two weakly-interacting metal centers. In Ru2 and Os2, the intense fluorescence of L subunit (λ max , 535 nm; τ, 4.3 ns; Φ, 0.91) is fully quenched, mainly by photoinduced electron transfer from the metal centers, on the ps timescale (time constant, 11 ps in Ru2 and 3 ps in Os2). Such photoinduced electron transfer leads to the formation of a charge-separated state, which directly decays to the ground state in about 70 ps in Os2, but produces the triplet π-π* state of the PBI subunit in 35 ps in Ru2. The results provide information on the excited-state processes of the hybrid species combining two dominant classes of chromophore/luminophore species, the PBI and the metal polypyridine complexes, and can be used for future design on new hybrid