Electrical Conductivity in a Laser Beam Channel

Russian Physics Journal - Electrical conductivity in a laser beam channel has been investigated. Oscillations of the conductivity caused by the oscillation motion of electrons in laser-induced...     

Electrical Conductivity of Nonideal Plasma

The electrical conductivity of fully ionized moderately nonideal plasmas with coulomb interaction parameters 0.1 < ? ? 1 where ? = Ze2n1/3/KT is the ratio of coulomb and thermal energies is calculated for displaced Maxwell and Fermi electron distributions, respectively. The electrons are scattered by an effective coulomb potential ?(r) = Zer-1 exp (-r/?) which considers binary (0 < r < ?) and many-body (? < r < ?) interactions. The shielding distance is given by ? = ?(4?n/3Z)-1/3 with ? = ?0?-N ~ 1 for classical plasmas and ? = ?(4?n/3Z)-1/3 with ? = ?0?-N?-M ~ 1 for quantum plasmas, where ? = Ze2n1/3/h2 m-1n2/3 is the ratio of coulomb interaction and quantum potential energies of the electrons. It is shown that the resulting conductivity formulas are applicable to densities up to four orders of magnitude higher than those of the ideal conductivity theory, which breaks down at higher densities because the Debye radius loses its physical meaning as a shielding length and upper impact parameter.     

Electrical Conductivity in General Relativity

The general relativistic kinetic theory including the effect of a stationary gravitational field is applied to the electromagnetic transport processes in conductors. Then it is applied to derive the general relativistic Ohm's law where the gravitomagnetic terms are incorporated. The total electric charge quantity and charge distribution inside conductors carrying conduction current in some relativistic cases are considered. The general relativistic Ohm's law is applied to predict new gravitomagnetic and gyroscopic effects which can, in principle, be used to detect the Lense-Thirring and rotational fields.     

Mechanism of Electrical Conductivity and Thermal Conductivity in AgSbSe2

Russian Physics Journal - Research was done on electrical conductivity and thermal conductivity of AgSbSe2 in the temperature range of 80–330 K. It was demonstrated that charge transfer in...     

Radiation-Induced Electrical Conductivity of Nanocomposite Materials

The radiation-induced conductivity of a nanocomposite with the inclusion of spherical nanoparticles as a function of intensity and time of action of gamma-radiation and the concentration and size of inclusions has been studied using the Rose–Fowler–Weisberg model. The energy spectrum of localized states associated with the nanoparticle inclusion has been determined. The numerical experiments have been made for polymethyl methacrylate (PMMA) nanocomposites with inclusion of CdS and α-Al₂O₃ nanoparticles as well as SrO nanoparticles.     

Electrical Conductivity of Nonideal Quasi-Metallic Plasmas

Electrical conductivity formulas are derived from first principles for fully ionized nonideal plasmas. The theory is applicable to an electron-ion system with a 1) Maxwell electron distribution with an arbitrary interaction parameter ? = Ze2n1/3/KT (ratio of the mean coulomb interaction and thermal energies) and 2) Fermi electron distribution with an interaction parameter ? = Ze2n1/3h?2m-1 n2/3 (ratio of the coulomb interaction and Fermi energies). The momentum relaxation time of the electrons in the plasma is calculated based on plane electron wave functions interacting with the continuum oscillations (plasma waves) through a shielded coulomb potential Us(r) = esee exp (-r/?s)/r, which takes into account both electron-ion interactions (s = i) and electron-electron interactions (s = e). It is shown that the resulting conductivity formulas are applicable to higher densities, for which the ideal plasma conductivity theory breaks down because the Debye radius loses its physical meaning as a shielding length and upper impact parameter. The conductivity obtained for classical plasma is of the form ?c = ?c*(KT)3/2/m1/2e2 and agrees with the ideal plasma conductivity formula with respect to the temperature and density dependence for ?/Z ? 0, but its magnitude is significantly reduced as ?/Z increases. For quantum plasmas, the conductivity obtained is of the form ?Q = ?Q*h3n/m2Ze2, which shows that the degenerate plasma behaves like a low-temperature metal.     

Superconducting Nanowire Single Photon Detector with Optical Cavity

Increasing the detection efficiency(DE)is a hot issue in the development of the superconducting nanowire single photon detector(SNSPD).In this work,a cavity-integrated structure coupled to the SNSPD is used to enhance the light absorption of nanowire.Ultra-thin Nb films are successfully prepared by magnetron sputtering,which are used to fabricate Nb/Al SNSPD with the curve of 100 nm and the square area of 4×4μm~2 by sputtering and the lift-off method.To characterize the optical and electrical performance of the cavity-integrated SNSPD,a reliable cryogenic research system is built up based on a He~3 system.To satisfy the need of light coupling,a packaging structure with collimator is conducted.Both DE and the dark count rates increase with I_b.It is also found that the DE of SNSPD with cavities can be up to 0.17% at the temperature of 0.7 K under the infrared light of 1550 nm,which is obviously higher than that of the SNSPD directly fabricated upon silicon without any cavity structure.     

Improvement of the Conductivity of Silver Nanowire Film by Adding Silver Nano-Particles

The change of conductivity and transparency of silver nanowire(AgNW) films by adding silver nano-particles(AgNPs) onto their surface is studied.The results show that the conductivity of the AgNW film is greatly improved with its sheet resistance reduced about 78.7% to 51.9 Q/sq,and there is no obvious reduction of the transmittance.Further studies show that there is a self-assembling process pushing the AgNPs to concentrate at the intersecting points between AgNWs to weld them,which would reduce the intersection resistance between the AgNWs.This self-assembling behavior is led by the surface interactivities among the dispersing liquid of AgNPs,the surface of the substrate and AgNWs when the dispersing liquid is drying.     

人工触发闪电通道的导电特性

用光学多道分析仪(OMA)获得了山东地区人工触发闪电回击过程的发射光谱.与以往的自然闪电光谱相比,除了氮、氧的中性原子及一次电离的离子谱和Hα谱线外,这次人工触发闪电的光谱还记录到了微量元素ArⅠ 602.5 nm及ArⅡ 666.5 nm的谱线.在局部热力学平衡近似下,根据光谱线的相对强度等参量,计算了闪电通道等离子体的温度;利用Hα线的Stark加宽、通过半经验方法获得了闪电通道的电子密度;首次结合等离子体理论得到了闪电通道的电导率,并由此讨论了通道的导电特性,分析了通道电导率与回击电流之间的相关性,为进一步计算回击电流提供了参考数据.结果分析得出:闪电通道是良导体,电子是通道电流的主要载体;一般情况下,人工触发闪电的通道亮度比自然闪电通道大,而通道回击电流小于自然闪电.     

On the Calculation of the Electrical Conductivity of a Nonideal Hydrogen Plasma

The electrical conductivity of a nonideal hydrogen plasma is calculated within the linear response formalism. The approximation given involves the first term with respect to the density expansion in the low degenerate case. The contributions of the free-free scattering of the particles as well as the bound-bound, bound-scattering, and scattering-scattering parts due to multiple scattering are discussed up to this level.     

Electrical Conductivity of Noble Gases at High Pressures

We present experimental and theoretical results for the electrical conductivity of noble gases (He, Ne, Ar, Kr, Xe) up to high pressures where a transition from nonmetallic to metallic‐like conductivities occurs. In addition, we show the behavior of the thermal conductivity and thermopower for xenon as an example. The experiments were performed using explosively driven shock waves. Different geometries allow to probe various parameter regions up to several megabars. Besides single‐shock experiments along the principal Hugoniot curve, also multiple‐shock experiments were performed which follow almost an isentrope. The theoretical calculations were performed within a partially ionized plasma model. The composition is determined by solving a system of mass action laws. The transport coefficients are calculated within linear response theory taking into account the relevant scattering mechanisms of electrons at different ion species, atoms, and other electrons. The general trends of the experimental results can be explained within this theoretical approach. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Electrical Conductivity Measurement Through the Loaded Q Factor of a Resonant Cavity

We present a method for measuring the electrical conductivity of metallic materials that relies on the ratio of two loaded Q factors, Q_R/Q_X, with Q_R corresponding to a TE₀₁₁-mode reference cavity made of aluminum, and Q_X the Q that results upon replacing the aluminum plate with the one fabricated from the material to be examined. Electrical conductivity is mathematically inferred from the ratio Q_R/Q_X where the loaded Q factors are measured by using the transmission-type method. Within a 3.0 percent accuracy, conductivities determined at 8.7 GHz for electrolytic copper (5.6 times 10⁷ S/m) and brass (1.6 times 10⁷ S/m) show to be in good agreement with those reported in the literature.     

介电力显微镜探测氧化锌纳米线表面吸附分子对电导率的影响

利用场效应晶体管器件和介电力显微镜来研究氧化锌纳米线表面吸附分子对其电导率的影响. 相比于空气中,ZnO纳米线场效应晶体管器件在氮气中电导率更高,介电力显微镜得的介电信号也是在氮气中更大. 影响ZnO纳米线电导率变化的主要原因是表面吸附分子数量的变化,而并不是电极与材料之间接触性质的变化.     

Kinetic Approach to the Electrical Conductivity in a Partially Ionized Hydrogen Plasma

The electrical conductivity is investigated for a partially ionized hydrogen plasma, starting from a generalized quantum kinetic equation with three particle collision integrals. To take into account plasma effects, screened potentials are used. The transport cross sections of the considered two and three particle scattering processes are calculated by perturbative solution of the Lippmann-Schwinger equations for the T-matrices up to the second Born approximation. In connection with a mass action law the influence of the electron-electron and the elastic electron-atom scattering is discussed. The pressure ionization (Mott-effect) is described by a minimum-behaviour of the electrical conductivity.     

Electrical Conductivity Oscillations in Laminated Charge-Ordered Crystals with a Monotonic Negative Reluctance

In the present paper, the Shubnikov–de Haas oscillation frequencies arising in laminated charge-ordered crystals with a monotonic negative reluctance due to scattering of current carriers on charged impurities with a short-range potential are calculated and classified. It is demonstrated that non-semiclassical oscillation frequencies can be a measure of charge ordering.     

Calculations of Electrical Conductivity of Ag and Au Plasma

The conductivity of silver and gold plasma is calculated within the relaxation‐time approximation at T ≥ 10 kK. The most accurate at present time momentum cross‐section for electron‐atom scattering was used. The ionic composition of plasma was calculated by means of generalized chemical model (GCM). The results of calculation were compared with the available data of others researchers (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Induced Electrical Conductivity of Gamma Irradiated S-Hydroxyquinolinc Metal Complexes

The effect of gamma radiation on the electrical conductivity σ of 8-hydroxyquinoline metal complexes was studied. The induced electrical conductivity for the investigated compounds was found to decrease on increasing radiation dose and approaches nearly that of the ligand at doses range from 3 to 5 MGy (300 to 500 Mrd). On the other hand, the increase in the activation energy ΔE by irradiation was found to depend on the crystal field stabilization energy (C.F.S.E.) in high spin tetrahedral field and the ionic potential of the metal.     

QED Electrical Conductivity from the 3PI Effective Action

We study the electrical conductivity in QED using the resummed 3PI effective action to 3-loop order. The resulting expression for the conductivity is explicitly gauge invariant, and the integral equations that resum the pinching and collinear contributions are produced naturally by the formalism. All leading order terms are included, without the need for any kind of power counting arguments.