二极管对

Most of the molecular characteristic absorption is very weak, and the absorption line width is very narrow that can't be measured by traditional methods.

TDLAS系统的关键是利用激光二极管有很高光谱分辨率和可调谐性的特点，可以对特定分子在特定光谱范围内的一条振转线的光谱吸收进行测量而反演吸收气体的浓度，而且能够把待测分子与背景的干扰区分开来。

And a new kind of peak detection module which is implemented by Verilog HDL in FPGA and greatly enhances the performance of catching glitch is discussed in the dissertation. The waveform recorder function accomplished in the ScopeMeter can test, monitor slow analog signals and record the characteristic value of signals continuously for a long time.

在示波表有限的空间内集成了3 3/4位数字万用表功能模块，能够实现对交直流电压、电流、电阻、二极管的测量，扩展了示波表的多用途功能，方便了用户现场使用。

It locks the frequency of the carrier-wave at 35MHz.The stabilization of the carrier-wave can be 4×10-5,the accuracy can be 3×10-5.The frequency modulation and the confection of the carrier-wave are realized by the capacity-changing diode V149 and the integration voltage-control oscillator MC1648 chip.The end power amplifier uses the audion 2SC1970 to make it work in the third magnifying state,it improves the efficiency of the magnifier and the power of the output reaches the design demand.

发射部分采用锁相环式频率合成器技术， MC145152和MC12022芯片组成锁相环，将载波频率精确锁定在35MHz，输出载波的稳定度达到4×10-5，准确度达到3×10-5，由变容二极管V149和集成压控振荡器芯片MC1648实现对载波的调频调制；末级功放选用三极管2SC1970，使其工作在丙类放大状态，提高了放大器的效率，输出功率达到设计要求。

The transmit part adopts the phase-locked loop pattern of frequency synthesizing technology and uses the MC145152 and MC12022 chips to compose the phase-locked loop.It locks the frequency of the carrier-wave at 35MHz.The stabilization of the carrier-wave can be 4×10-5,the accuracy can be 3×10-5.The frequency modulation and the confection of the carrier-wave are realized by the capacity-changing diode V149 and the integration voltage-control oscillator MC1648 chip.The end power amplifier uses the audion 2SC1970 to make it work in the third magnifying state,it improves the efficiency of the magnifier and the power of the output reaches the design demand.

发射部分采用锁相环式频率合成器技术， MC145152和MC12022芯片组成锁相环，将载波频率精确锁定在35MHz，输出载波的稳定度达到4×10-5，准确度达到3×10-5，由变容二极管V149和集成压控振荡器芯片MC1648实现对载波的调频调制；末级功放选用三极管2SC1970，使其工作在丙类放大状态，提高了放大器的效率，输出功率达到设计要求。

The converter can be improved just by exchanging the position of the resonant inductance and the transformer such that the transformer is connected with the lagging leg. The improved converter has several advantages over its counterpart, e.g., the clamping diodes conduct only once in a switching period, and the resonant inductance current is smaller in zero state, leading to a higher efficiency and reduced duty cycle loss. The operation principle of the improved converter and the comparison with the original converter are analyzed in this paper. The effect of the blocking capacitor in series with the transformer or resonant inductance is discussed, and a best scheme is determined.The improved converter is adopted to design the DC/DC converter of secondary power supply in HVDC power system.

本文将谐振电感和变压器交换位置，使变压器与滞后桥臂相连，这样箝位二极管在一个开关周期中只导通一次，同时零状态时谐振电感电流较小，有利于提高变换效率和减小占空比丢失，本文分析改进后变换器的工作原理，并与改进前的变换器进行对比，讨论隔直电容在不同位置对变换器工作的影响，确定一种最佳工程方案。

Simulation of PN junction diode lays the foundation for the simulations of other semiconductor elements.

本文结合非耦合数值方法，通过求解半导体方程对PN结二极管进行模拟分析，得到了一些重要物理参量分布，这为深入研究电磁辐射对半导体元件的干扰奠定了基础。

Based on the laser longitudinal mode splitting theory, a novel scheme of dual-frequency laser with large frequency-difference is presented using electrically controlled birefringence of liquid crystal, and the transmitted resonant mode splitting by birefringent of Fabry-Perot etalon has been analyzed theoretically. A new element of liquid crystal Fabry-Perot etalon is designed and fabricated, which serves as aselector and splitter of both laser longitudinal modes and Fabry-Perot etalons transmitted resonant modes. Two different experimental systems of laser-diode end-pumped Nd:YAG laser have been set up using two different LDs, and the transmission of liquid-crystal cell have been measured. When the empty LCFP is inserted in the cavity of high-power LD pumped Nd:YAG laser, the oscillation of a single laser longitudinal mode have been observed, such a result shows that the designed and fabricated LCFP element is capable of selecting single axial mode. While an anti-reflected liquid crystal cell is inserted in the cavity of Nd:YAG laser end-pumped by the high-power LD, it is difficult to confirm weather the laser longitudinal modes have been spitted or not. The subject is summarized in this thesis and the improvement of the project has been presented.

论文以激光纵模的分裂理论为基础，提出了可望获得几十GHz甚至上百GHz的液晶电控双折射双频Nd：YAG激光器的总体方案，并对用双折射效应分裂F-P标准具透射谐振模进行了理论分析；设计并加工了一种集激光纵模选择、激光纵模分裂和F-P标准具谐振透射模分裂于一体的多功能元件——液晶电控双折射F-P标准具；建立了两种不同功率激光二极管端面泵浦的Nd：YAG激光实验系统，并对液晶盒的透射性质进行了测试；将未灌注液晶的空液晶F-P摘要标准具插入大功率LD泵浦Nd：、叭G激光谐振腔内，观察到了单纵模激光输出，说明所设计和加工的液晶F一P标准具具有纵模选择能力；将镀有增透膜的液晶盒插入大功率LD泵浦Nd八7AG激光谐振腔内，是否产生了激光纵模分裂现象还难以确定。

Extensive studies have been made on organic and polymeric light emitting diodes because of their practical application as well as inherent scientific interest. Polymer LEDs using Poly (p-Phenylene Vinylene) were first reported in 1990 by Friend Research group and since then various other kinds of conjugated polymers have been developed which exhibit electroluminescence.

自从1990年英国剑桥大学Friend研究小组用聚对苯撑乙烯制作发光二极管以来，人们对PPV及其衍生物的电致发光性能进行了广泛研究并且取得了很大进展。

The absorption properties of Nd:YVO4 crystals with various doping levels and lengths are reported.The 1 064 nm laser properties are compared,and the effective stimulated emission crosssections of different doping levels are calculated with upper-level life-times we have measured.Our investigation give a good advice for the optimization of LD end-pumped Nd:YVO4 laser.

对多种掺杂浓度、长度的Nd：YVO4晶体进行了吸收性质、激光性质的研究和对比，根据实验结果和测得的上能级寿命计算了不同掺杂浓度Nd：YVO4晶体的有效受激发射截面，对激光二极管端面泵浦Nd：YVO4固体激光器的最优化有实际指导意义。

The experiments show that the Au/n-ZnO/p-Si SHBT UV enhanced phototransistor enhances the sensitivity of the ultraviolet response noticeably. The UV response sensitivity at 370nm of the phototransistor is 5～10 times that of a ZnO/Si heterojunction UV enhanced photodiode.

实验显示Au/n-ZnO/p-Si结构的紫外增强型的光电三极管对紫外光的响应明显增强，对371nm波长的紫外光的灵敏度是普通n-ZnO/p-Si异质结紫外光电二极管道的5～10倍。

In the negative and interrogative forms, of course, this is identical to the non-emphatic forms.

。但是，在否定句或疑问句里，这种带有"do"的方法表达的效果却没有什么强调的意思。

Go down on one's knees;kneel down

屈膝跪下。。。下跪祈祷