脉冲

In order to study the influence of UV pulse laser pre-treatment on surface image of fused silica and validate its upgrade effect on anti UV laser damage ability of fused silica,using 355nm YAG laser raster to scan fused silica optics by means of power increase by degrees periodically,the change of surface image was studied and its anti-laser damage threshold at 355nm was measured.

为了研究紫外脉冲激光预处理对熔石英表面形貌的影响，验证其对熔石英元件抗紫外激光损伤能力的提升效果，利用输出355nm 3倍频紫外脉冲激光的YAG激光器，采用光栅式扫描的方式对熔石英表面进行了全口径能量周期递增的激光预辐照处理，并在处理结束后研究了表面形貌的变化，考核了其在355nm脉冲激光作用下的损伤阈值。

In this dissertation, some research on the contact reliability of relay has been made on the basis of a new measuring method for contact resistance that is the pulse current method. The thermal propagation has been analyzed so as to analyze the thermal effect of pulse current flowing over contact.

本文在提出一种新的测量接触电阻方法——脉冲电流法（脉冲宽度为300μS）的基础上，针对继电器接触可靠性进行了研究，并对触点热过程进行了分析，以便分析脉冲电流对触点产生的热效应。

Resonant laser ablation is a two-step process, occurring within a pulse of a tunable laser, in which the leading edge of the laser pulse ablates the surface of the solid sample to produce neutral atoms or molecules that are then resonantly ionized by the trailing edge of the same pulse.

共振激光烧蚀技术是指发生在同一激光脉冲时间内的两步过程，它是指用波长可调谐的染料激光取代固定波长输出的激光，并调谐激光输出波长实现所研究原子或分子电子态之间的共振跃迁，激光单次脉冲的前沿对样品进行烧蚀，烧蚀的物质在激光光束内形成粒子气团，同一次激光脉冲的后沿实现对气相原子或分子的共振电离。

In the condition of definitive structural parameter and part of operative parameter of impulse engine, the effect of controlling force of impulse engine on correct trajectory is analysed. The number of total layer, impulse of each impulse engine and fire interval are determined when the correct ability and flight stability are satisfiable.

在确定了脉冲发动机的结构参数和部分工作参数的情况下，分析了脉冲发动机控制力对修正弹道的影响能力，确定了在满足修正能力及飞行稳定性的条件下脉冲发动机的总层数、单冲和点火间隔。

The principles and methods of present tangent method and secant method are also described in the paper.

全压力史拟合方法的理论模型是：地层均质、等厚、无限大，充满弱可压缩流体，考虑井筒中存在表皮效应和井筒存储的影响 3、通过使用有限元法对脉冲试井过程进行了数值分析计算，得到了脉冲试井的不同条件下的理论曲线，提出了脉冲试井数值分析方法。

With the shadowgraph method, three ultrasonic pulses in water, which corresponds to the conversion modesof the fast compressional wave the transverse wave and the slow compressional wave in the sample of fluid-saturatedporous medium respectively, were observed and recorded by CCD camera.

用阴影法和CCD照相，观测到声脉冲透过流体饱和孔隙介质（按英文"Fluidsaturatedporousmedum"的第一个字母缩写为FSPM）样品后在水中传播的三个声脉冲，这三个声脉冲分别对应于FSPM样品中的三种体波的转换模式。

The drift and jitter of the output pulse are important parameters of the stability.The experiments and analyses based on homemade VE-4073 thyratron show that the combined effects of DC heating thyratron and two-pulse triggering technique can greatly reduce the drift and jitter of the pulser output.

利用国产VE-4073氢闸管进行了分析和实验研究，通过采用直流加热氢闸管灯丝和氢储存器，以及精确、稳定的双脉冲触发技术，大幅减小了开关脉冲发生器触发延时的抖动和漂移，48 h内开关脉冲发生器输出漂移仅6.1 ns。

In recent years, cold cathode thyratron KN-22 is widely used in circuit, but here KN-22 is replaced by MOSFET. The circuit with MOSFET has stable and credible performance, it can output a pulse of -6.6～-8kV and the pulse width can be adjusted from 5ns to 10ns.

应用冷阴极闸流管KN-22作为开关线路比较广泛，但近年来我们改用MOS场效应管线路代替KN-22，该线路性能稳定可靠，输出脉冲幅度为-6.6～-8kV，脉冲宽度5～10ns可调，触发晃动小于0.5ns，触发延时30～40ns，单脉冲选出率为100%。

Thus the pulse parameters were determined based on examination of the microstructure, grain size, hardness and tensile strength of the deposits obtained at different average current densities with constant pulse-on time (ton =2 ms) and pulse-off time (toff= 45 ms).

结果表明，在恒定脉冲模式下(脉冲导通时间2ms，脉冲断开时间45ms)，镀层晶粒尺寸随电流密度的上升而明显下降，硬度与强度则显著上升，当电流密度超过8A/dm2时，抗拉强度开始急剧下降而硬度保持6kN/mm2的高位基本不变，当超过12A/dm2时，硬度也开始下降。

The result indicate that: the electrodeposition of zinc on nickel and tungsten substrates involves instantaneous three-dimensional nucleation. The coating is the best when the current density is 4mA/cm2 and the temperature is 80 ℃. The coating by the method of the impulse electrodeposition is better than the direct current electrodeposition. Especially when f is 100Hz, ton/toff is 2/8 and J is 8mA/cm2, the coating is clean and uniformity. The crystal size is nearly 0.3μ m .

结果表明：阴极反应为准可逆反应，锌离子在镍电极和钨电极上形核是三维瞬时形核半球形扩散长大过程，直流电流密度为4mA/cm2，温度为80 ℃时，镀层质量最好；脉冲电沉积得到的镀层要优于直流电沉积得到的镀层，尤其在脉冲宽度为2ms，脉冲间隔为8ms，电流密度为8mA/cm2时，得到的镀层光滑而均匀，颗粒大小接近0.3μm。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。