电流

The expressions of the scattering signal of AOSLDA, first obtained by electro-magnetic radiation formula on the assumption that the measurement volume moves in a uniform velocity, were shown.

在测量点以锯齿波方式移动的情况下，对声光扫描LDA的光电流信号做了进一步分析，得到不同空间位置处的散射粒子所产生的光电流信号的交流振动次数及其变化规律。

The foundation of this system provides a good reference to promote the standardization and intelligence of the overhaul and maintenance of vacuum switches. This paper develops a special HF pulse power supply for internal pressure estimation, which achieves the output of HF-HV sinusoidal pulse wave whose frequency and amplitude can be modified respectively, and meets the design requirements according to the results of Simulink simulation and practical experiments. With the help of AT89S52, this paper designs an I~2C serial bus based signal detection system for peak value signal acquisition of HF pulse currents, which communicates with the upper computer by asynchronous serial communication for uploading the data. In the upper computer, a human computer interface is developed by Matlab software, whose functions are to do some computation and graphic display, such as calibrating the relation curve of vacuum degree and peak value of HF pulse currents, vacuum degree computation, and vacuum lifetime evaluation analysis basing on grey forecasting model as well as making relative suggestions.

本文研制了用于真空度检测的高频脉冲电源，通过Simulink仿真和试验检验其满足设计要求，实现了电压幅值和频率独立可调的正弦波高频高压脉冲输出；利用以AT89S52为核心基于I~2C串行总线的信号检测系统实现高频脉冲电流峰值信号的采集，通过异步串行通信实现单片机与计算机之间的数据通信，将检测数据传至上位机；在上位机利用Matlab开发人机交互界面，实现相关数据处理和图形显示，包括真空度——高频脉冲电流峰值关系曲线标定、真空度数值计算、基于灰色预测模型的真空寿命评估分析和提出相应决策建议。

The characteristics of pentacene/perylene derivatives based organic solar cells are investigated in this thesis Donor and acceptor layers are pentacene and N N'-dioctyl-3 4 9 10-perylenetetracarboxylic diimide (PTCDI-2~13C) respectively Twelve organic solar cells with pentacene/PTCDI-2~13C heterojunctions were fabricated to study the influence of various alkylic perylene derivatives on the power conversion efficiency Under the sunlight simulator with AM1 5G filter and 100 mW/cm2 the solar cell of pentacene/PTCDI-7C heterojunction with cathode of Ag/Al bilayer has the best performance among the devices with pentacene/PTCDI-2~13C heterojunctions In PL spectrum analyses the pentacene/PTCDI-7C film had lower recombination rate than the other pentacene/PTCDI-2~13C films; therefore more excitons could reach the P/N junction and enhance short-circuit current Furthermore the PTCDI-7C film grown on the surface of penatcene was more matched than other PTCDI films analyzed by the PL peak shifts of 10 nm and 45 nm thick PTCDI-2~13C and images of atomic force microscope More lattice match between the films of pentacene and PTCDI resulted in fewer defects in P/N junction and more carries can reach electrodes Accordingly the power conversion efficiency approach 2% was obtained from the solar cell with the active layer of pentacene/PTCDI-7C

本研究探讨以五环素/骈苯衍生物异质接面太阳能电池之特性，利用pentacene作为电子施体有机材料，PTCDI -2C~13C作为电子受体有机材料，制作出异质接面为pentacene/ PTCDI-2C ~13C等12种有机太阳能电池，比较不同碳数的骈苯衍生物对於有机太阳能电池之光电转换效率之影响。在AM1 5G、100 mW/cm2的模拟太阳光下，以pentacene/PTCDI-7C异质接面太阳能电池具有短路电流9 882 mA/cm2、开路电压0 376 V、填充因数0 523及光电转换效率达1 945%，皆比其他pentacene/PTCDI-2C ~13C异质接面太阳能电池来的大。由薄膜分析可知PTCDI-7C在这12种太阳能电池中具有较低的电子电洞复合发光效率，可以让较多激子到达异质接面进行电荷分离，减少电子电洞对复合发光的机率；此外，由光激发萤光光谱之峰值位移配合原子力显微镜表面结构图，可以得知当PTCDI-7C成长在pentacene上时会顺著pentacene的结构成长薄膜，故较无缺陷产生在P/N接面处；而在其他结构下则无此现象产生，致使在pentacene/PTCDI-7C薄膜中的载子有较大的机会可以移动至电极，使光电流提高，进而使光电转换效率提高。

In order to study the negativesequence influence to regional power grid caused by autotransformer traction power supply system, formulas of NSeq current and threephase voltage imbalance were derived, based on current distribution analysis of AT traction power supply system and singlephase VVconfiguration train substation. Employing the "train diagram" method, the realtime voltageimbalance curve was obtained in a simulation study, as well as the factors that influence NSeq and some measures to restrain it.

为研究自耦变压器牵引供电系统对地区电网造成的负序影响，首先讨论了AT牵引供电系统、单相VV接线牵引变电站的电流分布，推导得出了负序电流、三相电压不平衡度的计算公式；然后结合"列车运行图法"开发了相应的仿真程序；最后通过一个实际算例，得到了实时电压不平衡度曲线，指出了负序大小的影响因素及相应措施。

The effect of different discharge electrodes and settings on the experiment results is discussed in terms of average current density and relative deviation.

采用实验和数值计算相结合的方法，以极板表面平均电流密度、电流密度相对标准差为指标对电场性能进行了评价和预测，给出了几种电场性能较好的电极配置形式和几何参数调整范围。

Simulated annealing method was used to get the least average relative error for a given temperature.

利用神经网络分析了频率和电流对平均温度及其平均相对误差的影响，并应用模拟退火法对频率和电流进行了优化以获得所需温度下的最小平均相对误差。

In this paper, state-space averaging method is used to establish the small signal model of current regulator.

本文用状态空间平均法建立了电流调节器的充放电小信号数学模型，并在此基础上分别设计了电流调节器的充放电控制器，其中充电控制器采用滞环＋PI调节的方式。

A current detection method is also proposed which is based on the BLDCM back electromotive force.

通过比较几种常用的电流检测方法，文中还探讨了一种基于无刷直流电动机反电动势的电流检测方法。

In addition, the primary causation for the problem that phase current during reverse braking process out of control is a short loop by the back electromotive force.

同时，针对反接制动时电流无法控制的问题，该文指出反电动势短接回路的存在是造成再生电流无法控制的主要原因。

In this paper, the change of back electromotive force current with the different PWM modes are analyzed in detail on the base of BLDCM model. According to theory and experiment ,ON-PWM type restrains the peak value of back electromotive force current and brings the lest effect to the motor control system.

基于无刷直流电动机的数学模型，分析比较了不同PWM调制方式下反电势电流的变化规律，并通过理论推导和仿真实验证明了当电机系统采用ON-PWM调制方式时，能有效地抑制反电势电流的峰值且对电机控制系统造成的影响最小。

I will endeavour to find you some assistance.

我尽力帮你找人帮忙。

At first I only know bruck is the idol of American younglings, afterwards I returned back to Taiwan ,even in Beijing last year ,I saw her poster everywhere, I was so surprised at her charm.

起初我只晓得布鲁克雷德丝是美国少男少女崇拜的偶像，后来回台湾，甚至去年在北京，居然也四处看见她的海报，才惊讶她的魅力之大。