聚丙烯孔洞铁电驻极体膜的电极化及其电荷动态特性

根据栅控恒压电晕充电组合反极性电晕补偿充电法的实验结果计算出铁电驻极体的极化强度.结果说明，伴随着薄膜内孔洞气体的Paschen击穿，该铁电体的极化强度随栅压增加而显著上升.利用上述充电方法和热刺激放电(TSD)谱的分析讨论了这类空间电荷型宏观电偶极子，及与其补偿的空间电荷热退极化的电荷动态特性；阐明了这两类俘获电荷的能阱分布，即构成宏观电偶极子的位于孔洞上下介质层内的等值异号空间电荷分别被俘获在深、浅两种能值陷阱内，而位于薄膜表面层的注入空间电荷则被俘获在中等能值陷阱中. 关键词： 反极性电晕补偿充电法 铁电驻极体 充电电流 热刺激放电     

为什么不能用Q=It来计算充电电流——由一道高三试题引发的争议

由一道师生剧烈争议的高三试题,联系实际生活对题中电动车的充电电流的求解进行分析.(1)较高的充电电压不是直接施加于电池;(2)为什么要采用高压充电;(3)高压充电的其他生活应用实例.     

计时电流的因子分析-法拉第电流与充电电流的分离

基于电化学理论电流公式,用迭代目标变换因子分析法对计时电路曲线进行处理,得到分离的法拉第电流和充电电流成分,对于简单的电极过程,分离效果很好,信噪比得到提高,法拉第电流分量可用于定量分析。     

Generation of adjustable pure spin currents in negative-U systems

Single-particle sequential tunneling is studied through a negative-U center hybridized with a superconducting, a ferromagnetic, and a normal metal electrodes. In stark contrast to the case of positive U, the single-particle tunneling in attractive charging energy is usually prohibited by ground states with electrons in pairs. We find a microscopic mechanism to induce single-particle sates from pair states. As a consequence, in the nonpolarized metal terminal a remarkable pure spin current with no charge currents survives over a wide range of gate- and bias- voltages, which is rather crucial for experimental observation and design of spintronic devices. In addition, a significant spin-filter effect is presented in certain bias regime.     

Persistent current in a magnetized Rashba ring

We theoretically study the persistent currents flowing in a Rashba quantum ring subjected to the Rashba spin-orbit interaction. By introducing uniform or nonuniform magnetization into the ring, we find that a nonzero persistent charge current circulates in the ring, which stems from the original equilibrium spin current due to the Rashba spin-orbit interaction. Because of broken time reversal symmetry, the two oppositely flowing spin-up and spin-down charge currents of the equilibrium spin current are no longer equal, and so a net persistent charge current can flow in the system. It is also found that the persistent current can be modulated by the Fermi energy, the Rashba spin-orbit interaction strength and the magnetization in the ring. Moreover, the magnetization perpendicular to the ring plane can optimize the current. The persistent current flowing in the ring is a manifestation of the nonzero equilibrium spin current existing in the ring.     

Origin of Electron and Hole Charging Current Peaks in Nanocrystal-Si Quantum Dot Floating Gate MOS Structure

The nanocrystal-Si quantum dot （nc-Si QD） floating gate MOS structure is fabricated by using plasma-enhanced chemical vapour deposition （PECVD） and furnace oxidation technology. The capacitance hysteresis in capacitancevoltage （C - V） measurements confirm the charging effect of nc-Si QDs. Asymmetric charging current peaks both for electrons and holes have been observed in current-voltage （I - V） measurements at room temperature for the first time. The characteristic and the origin of these current peaks in this nc-Si QD MOS structure is in- vestigated systematically. Moreover, the charge density （10^-7 C/cm^2） calculated from the charging current peaks in the I - V measurements at different sweep rates shows that each quantum dot is charged by one carrier. The difference of charging threshold voltages between the electrons and holes charging peaks, △VG, can be explained by the quantum confinement effect of the nc-Si dots in size of about 3.5 nm.     

Persistent Spin and Charge Currents in Open Conducting Ring Subjected to Rashba Spin--Orbit Coupling

We investigate persistent charge and spin currents of a one-dimensional ring with Rashba spin-orbit coupling and connected asymmetrically to two external leads spanned with angle φo. Because of the asymmetry of the structure and the spin-reflection, the persistent charge and spin currents can be induced. The magnification of persistent currents can be obtained when tuning the energy of incident electron to the sharp zero and sharp resonance of transmission depending on the Aharonov-Casher （AC） phase due to the spin-orbit coupling and the angle spanned by two leads φo. The general dependence of the charge and spin persistent currents on these parameters is obtained. This suggests a possible method of controlling the magnitude and direction of persistent currents by tuning the AC phase and φo, without the electromagnetic flux though the ring.     

银滴电极在示波极谱测定锌精矿中铅的研究与应用

<正>在极谱分析中,常使用的指示电极为滴汞电极,在测定时由于汞滴表面的不断增长,带来了相当于10-5 mol/L的金属离子还原电流的充电电流,导致极谱测定灵敏度难以超过10-5 mol/L,且滴汞电极     

Spin-excited states and rectification in an organic spin rectifier

Spin-excited states in an asymmetric magnetic organic co-oligomer diode are investigated theoretically. The results demonstrate that the structural asymmetry of the co-oligomer is modulated by the spin-excited states, which is embodied in the wave functions of the eigenstates as well as the spin density wave. By calculating the transport property, a robust spin-current rectification concomitant with a charge-current rectification is observed in all spin-excited states. However, the current through the diode is suppressed distinctly by the spin-excited states, while the rectification ratios may be reduced or enhanced depending on the bias and the excited spins. The intrinsic mechanism is analyzed from the spin-dependent trans- mission combined with the change of molecular eigenstates under bias. Finally, the temperature-induced spin excitation is simulated. Significant rectification behavior is obtained even at room temperature.