Messung des Starkeffektes am neutralen Stickstoffatom (NI)

By means of a light source described in a former publication¹ Stark effects in an inhomogeneous electrical field could be observed at numerous NI-lines in the spectral range between 4000 and 9000 Å. Quantitative measurement of the displacements of the line centres at electrical fields between 0 and 200 kV/cm yielded pure quadratic Stark effects in most cases. At a few lines however a transition from quadratic to linear effect has been found.     

直流老化及热处理对ZnO压敏陶瓷缺陷结构的影响

在电场为3.2 kV/cm, 电流密度为50 mA/cm²条件下对ZnO压敏陶瓷进行了115 h的直流老化, 研究了直流老化对ZnO压敏陶瓷电气性能及缺陷结构的影响. 发现直流老化115 h 后ZnO压敏陶瓷的电位梯度、非线性系数分别从2845 V/cm, 38.3下降到51.6 V/cm, 1.1, 介电损耗中的缺陷松弛峰被增大的直流电导掩盖, 电模量中只观察到一个缺陷松弛峰, 低频区交流电导率急剧增大并且相应的电导活化能从0.84 eV下降到只有0.083 eV. 通过对直流老化后的ZnO压敏陶瓷在800 ℃进行12 h 的热处理, 发现其电气性能和介电性能都得到了良好的恢复并有一定的增强, 电位梯度、非线性系数恢复到3085 V/cm, 50.8, 电导活化能上升到0.88 eV. 另外, 其本征氧空位缺陷松弛峰也得到了一定的抑制. 因此, 认为热处理过程中氧在晶界处的扩散作用对ZnO压敏陶瓷的直流老化恢复起到了关键作用. 关键词： ZnO压敏陶瓷 介电性能 直流老化 热处理     

Electrical conductivity of zone refined and impure 1, 5-diaminonaphtalene

The electrical conductivity of 1,5-diaminonaphthalene has been studied in the temperature range 30–110°C in a field varying from 2.7 kV/cm to 26.6 kV/cm. Measurements were made on pellets prepared from impure and zone refined material using embedded electrodes provided with a guard ring. For the impure sample the plot of log σ against 1/T showed two distinct regions with activation energies of 0.380 V and 1.21 eV. The two regions merged into one for the six times zone - refined samples with an activation energy of 0.77 eV.     

Effect of electric field on non-ideal plasma conductivity

An order of magnitude increase in plasma electrical conductivity with increase in electric field up to 10³ V/cm has been experimentally observed for plasma with ζ/Z ≈ 1, where ζ is the number of electrons in Debye sphere, Z = 1–3 is the stage of ionization. The effect vanishes at ζ/Z ? 10.     

The influence of argon ion bombardment on the electrical and optical properties of clean silicon surfaces

The effect of low energy noble gas ion bombardment on the electrical and optical properties of Si(211) surfaces has been investigated by surface conductivity and field effect measurements, ellipsometry and AES. With this combination of techniques, information is obtained concerning the electrical properties, the chemical composition and the damage of the surface layer. Upon ion bombardment in the energy range of 500–2000 eV, ellipsometry shows the formation of a damaged surface layer with optical properties close to those of an evaporated amorphous silicon film. In order to measure the conductivity changes as sensitive as possible, nearly intrinsic silicon crystals were used. For the clean, 5200 Ω cm Si(211) surface, bombarded only with a mass-analyzed argon ion beam, a small increase in conductivity is found to occur after a small ion dose (saturation after 5 × 10¹⁴ ions cm^?2 while after 5 × 10¹³ ions cm^?2 already half of the increase has occurred). The effect was found to be independent of ion energy between 500 and 2000 eV. As the field effect signal did not change after this treatment, it is concluded that the surface state density in the neighbourhood of the Fermi level shows a slight decrease.     

Study of the leader of a spark discharge over a water surface

This paper discusses an experimental study of the leaders of incomplete spark discharges with a capacitance of 0.1 and 1 μF over a water surface when the initial voltage is 3–6 kV in discharge gaps 8 and 22 cm long, having side branches and without branches. The distributions of the field, the current, the current density, the conductivity, and the electron concentration along the leader have been determined, as well as the changes in the velocity and length of the leader as it evolves. It has been established that the evolution of the leader has a self-maintained character, and that the product of the storage capacitance and the initial potential difference between the head of the leader and the water surface is an invariant of its spatial evolution. Zh. Tekh. Fiz. 68, 44–50 (July 1998)     

丝光沸石的电导性能研究

测量了天然丝光沸石的总电导率和电子电导率,不同含水量时的电导率和活化能以及不同交换离子时的电导率和活化能.研究表明,丝光沸石在自然环境中具有10^-5-10^-6(Ω.cm)^-1的电导率,以离子电导为主.丝光沸石电导率的变化反映了它的结构变化. 关键词：     

Effect of high electric field on the dc conduction of TeO2-V2O5-MoO3 amorphous bulk material

Effect of high electric field on the dc conductivity of TeO₂-V₂O₅-MoO₃ amorphous bulk samples with different molar ratio of each component was investigated with gap-type electrode arrangement. At low electric fields, the current-voltage (I–V) characteristics has a linear shape, while at high electric fields (>10³ V/cm), bulk samples show nonlinear behavior (nonohmic conduction) and current-voltage characteristics shows increasing deviation from Ohm’s law with increasing current density. High-field effect of Pool-Frenkel type was observed at electrical fields about 10³−10⁴ V/cm. In addition, positive deviation from Pool-Frenkel effect was observed when a field higher than about 10⁴ V/cm was applied.     

Positron annihilation in helium,argon and nitrogen liquids under an electric field

We have made new measurements of the lifetimes at 4.19 and 2.92 K in HeI, and at 2.14 and 1.67 K in HeII, without and with electric field. The ortho-positronium lifetime is independent of field up to 20 kV/cm. At 4.19 K, there is no increase observed in the positronium fraction from zero field to 20 kV/cm, in strong disagreement with Manuzio and Rizzuto. Some additional positronium is, however, formed above 20 kV/cm, with a corresponding decrease in lifetime of the free component. At 4.19 K the free positron mean life rises sharply with increasing electric field to a constant value of about 2.14 ns above 5 kV/cm. The increase in the free positron lifetime with field is less marked at 2.92 K. In liquid argon measurements were made at the normal boiling point only, at fields up to 20 kV/cm, above which we experienced electrical breakdown. The ortho-positronium intensity is 7% at zero field and begins to increase at 2.5 kV/cm, reaching 13% at 20 kV/cm at which field value it was still increasing. The ortho-positronium lifetime displayed an 8% increase over this field range. For liquid nitrogen we repeated some of our earlier measurements at 77.3 K and made some measurements at 64.5 K so as to test models for positronium formation in the spur. A good fit to a simple exponential formula is obtained at both temperatures, yielding a single drop-off rate of 0.21 cm/kV.On leave from the Physics Department, University of Toronto, Canada.     

Exchange of transverse plasmons and electrical conductivity of neutron star cores

We study the electrical conductivity in magnetized neutron star cores produced by collisions between charged particles. We take into account the ordinary exchange of longitudinal plasmons and the exchange of transverse plasmons in collisions between particles. The exchange of transverse plasmons is important for collisions between relativistic particles, but it has been disregarded previously when calculating the electrical conductivity. We show that taking this exchange into account changes the electrical conductivity, including its temperature dependence (thus, for example, the temperature dependence of the electrical resistivity along the magnetic field in the low-temperature limit takes the form ?_‖ ∝ T ^5/3 instead of the standard dependence ?_‖ ∝ T ² for degenerate Fermi systems). We briefly describe the effect of possible neutron and proton superfluidity in neutron star cores on the electrical conductivity and discuss various scenarios for the evolution of neutron star magnetic fields.     

长脉冲强流二极管径向绝缘研究

 介绍了一种应用于长脉冲强流二极管的径向绝缘结构。简介了真空表面闪络机理，径向绝缘结构的设计思路。采用锥形绝缘结构，使用计算机模拟静电场分布优化设计了几何结构参数，在脉宽为200ns的脉冲源上进行了实验研究。二极管最高输出电压为750kV，平均绝缘子表面耐电场强度约50kV/cm，达到了设计要求。     

The impact of 1-butyl-3-methylimidazolium chloride on electrospinning process of SAN polymer solutions and electrospun fiber morphology

The aim of this research was to investigate how addition of IL [Bmim]Cl¹ into SAN² solution in 1,2-DCE³ will influence electrospinning variables, stability of process and morphology of obtained nanofibers and find out the appropriate way of utilizing [Bmim]Cl in the electrospinning process. The solutions of pure SAN in 1,2-DCE of different concentrations (10–20%) and solutions with different concentrations (0.5–20%) of IL were spun at different variables (10–20 cm and 10–20 kV). All results were investigated by optical and SEM microscopy. Also solution parameters like electrical conductivity, surface tension and viscosity were measured and their effect on the obtained fibers morphology estimated.     

Untersuchungen zum Stark-Effekt metastabiler Terme im Ba I-Spektrum durch Nachweis von Hochfrequenzübergängen

By detection of r.f.-transitions between Zeeman-sublevels the Zeeman-splitting of the metastable 6s 5d-levels and of the 6s 6p³ P ₁-level of the even Ba-isotopes was investigated under the influence of an electric field in addition to a magnetic field. From the measurements the following tensor polarizabilities were deduced: α_ten(³D₃)=?29(5) kHz/(kV/cm)², α_ten(³ D ₂)=?13(3) kHz/(kV/cm)², α_ten(³D₁)=?10(2) kHz/(kV/cm)², α_ten(¹ D ₂)=?16(3) kHz/(kV/cm)². No effect due to electric fields up to 50 kV/cm was observed in the Zeeman-splitting of the 6s 6p ³ P ₁-level. Therefore the tensor polarizability of the 6s 6p³P₁-level must be much smaller than those of the 6s 5d-levels. The results will be discussed by considering the oscillator strengths both of the infrared transitions between the two multiplets 6s 5d ³ D and 6s 6p ³ P and of transitions to other low lying levels.     

Calculation of hot electron distribution functions and of the threshold field in the gunn effect

The Boltzmann equation is formulated for the (000) electrons in GaAs in the highenergy approximation taking into consideration acoustic, polar and nonequivalent intervalley scattering to the 〈100〉 satellite valleys and the nonparabolicity of the central valley. The simplified form of the equation permits a qualitative discussion of the shape of the electron density distribution without explicitly computing the distribution function and illustrates the effect of the various scattering mechanisms as a function of the electric field. Examples of electron density distribution curves are calculated for a few typical field values, and the result is used to derive the fielddependent population of the satellite valleys and the average drift-velocity in the vicinity of the Gunn threshold. For an intervalley deformation potential constant of 5×10⁸ eV/cm the threshold is found to be 2.7 kV/cm in the parabolic case increasing to 3.5 kV/cm when nonparabolicity is included. Comparison with experimental data is made.     

Electrical conductivity in single crystals of GaSe<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Te<Subscript>1 – <Emphasis Type="Italic">x</Emphasis></Subscript> solid solutions in strong electrical fields

This paper presents some results of studying the Poole–Frenkel effect with allowance for shielding in layered GaSe and GaTe single crystals and their solid solutions in strong electrical fields of up to 10⁵ V/cm at temperatures of 103–250 K. According to the relationship \(\left(\frac{\sigma}{\sigma(0)}\right)^{1/2}\) log\(\frac{\sigma}{\sigma(0)} = E\sqrt{\frac{\varepsilon}{4\pi n(0)kT}}\), there exists a linear dependence between \(\left(\frac{\sigma}{\sigma(0)}\right)^{1/2}\) log\(\frac{\sigma}{\sigma(0)}\) and the electrical field E (σ is the electrical conductivity in strong electrical fields, and σ(0) is the electrical conductivity in the ohmic region). The slopes of these lines have been determined at different temperatures (103–250 K) by estimating the concentration of current carriers n(0) = 3 × 10¹³–5 × 10¹⁵ cm^–3 in the ohmic region of the electrical conductivity of solid solutions of layered GaSe _x Te_1–x single crystals (x = 1.00, 0.95, 0.90, 0.80, 0.70, 0.30, 0.20, 0.10, 0).     

Generation and transport of high-current, low-energy electron beams in a system with a gas-filled diode

Investigations of the generation and transport of a high-current, low-energy electron beam are performed in a system with a gas-filled diode based on a plasma cathode. At accelerating voltages of up to 20 kV and pressures of (1–5)×10⁻¹ Pa, a beam with an emission current of 600 A, emission current density of 12 A/cm² and pulse duration of 30 μs if obtained in a diode with a grid-stabilized emission opening having a diameter equal to 8 cm. The beam is transported in the absence of an external magnetic field over a distance of 20 cm. The beam is compressed by its self-magnetic field, and the current density at the collector reaches 100 A/cm² when the beam diameter is 3 cm. Zh. Tekh. Fiz. 68, 44–48 (January 1998)     

Electrostrictive properties of thermoplastic polyurethane elastomer: Effects of urethane type and soft–hard segment composition

The electromechanical behavior of thermoplastic elastomer polyurethane (TPE-PU) is investigated under the effects of urethane type (ester and ether-types) and soft–hard segments at various electric field strengths and temperatures. The highest dielectric constant, electrical breakdown strength, and specific conductivity belong to the ester-type polyurethane (LPR matrix), while the lowest values are obtained from the ether-type polyurethane composing predominantly with the soft-segment (E 80A matrix). Under the electric field strength in the range between 0 and 2 kV/mm, the LPR matrix attains the storage modulus sensitivity (ΔG′/G′₀) up to 2 at 2 kV/mm. For the temporal response, the polyurethanes behave with good reproductively (number of cycles >10⁵ times) and with very good recoverability. The steady state behavior can be attained at the first actuation and at the electric field strength of 1 kV/mm. Furthermore, the storage modulus (G′) shows linearly negative responses with increasing temperature. In the deflection experiments, the deflection distance and the dielectrophoresis force increase monotonically with increasing electric field strength. All of the TPE-PU possesses very fast response times for activation (<10 s.) and deactivation (<5 s.). TPE-PU material is systematically shown here to be a potentially good actuator material with high efficiency based on the electrostrictive performance data obtained.     

The influence of high electric field strengths on the electric current in liquid benzene

The electric conductivity in the field strength range between 2 kV/cm and 110 kV/cm and the time dependence of the current after voltage application have been studied.     

Electrical properties of highly (111)-oriented lead zirconate thin films

Antiferroelectric PbZrO₃ thin films were grown on Pt/Ti/SiO₂/Si substrates with predominant (111) orientation using a sol-gel process. The Pt/PbZrO₃/Pt film capacitor showed well-saturated hysteresis loops at an applied voltage of 5 V with remanent polarisation (P_r) and coercive electric field (E_c) values of 8.97 μC/cm² and 162 kV/cm, respectively. The leakage current density of the highly (111)-oriented PbZrO₃ film was less than 1.0×10⁻⁷ A/cm² over electric field ranges from 0 to 105 kV/cm. The conduction current depended on the voltage polarity. The PbZrO₃/Pt interface forms a Schottky barrier at electric fields from 20 to 160 kV/cm. The dielectric relaxation current behaviour of Pt/PbZrO₃/Pt capacitor obeys the well-known Curie-Von Schweidler law at electric field of 20-80 kV/cm, the currents have contributions of both dielectric relaxation current and leakage current.     

Small-field D.C. conduction inn-type germanium in the presence of large microwave field

Small-field d.c. conduction inn-type germanium in the presence of large microwave field is theoretically studied assuming a Maxwellian distribution function for the carriers. Scattering by intra-valley acoustic and optical phonons and by equivalent inter-valley phonons have been taken into account, but the effect of non-equivalent inter-valley scattering has been neglected. The small-field d.c. conductivity is found to be appreciably different from the d.c. conductivity corresponding to the r.m.s. value of the microwave field and nearly frequency-independent up to a frequency of 35 Gc/s. The anisotropy in its values is also found to be of the same order as in the values of the high-field d.c. conductivity. The calculated values show close agreement with the experimental results in the field range 1 to 3 kV cm^?1 and for frequencies between 2.85 to 35 Gc/s.