不稳电路

This paper analyzed and researched the characteristics of Schmitt trigger, single-stable-state trigger and astable multivibrator constituted by 555 timer based on PSPICE. Against the phenomenon of astable multivibrator constituted by 555 timer has no oscillation in PSPICE, an effective analysis method was brought out for 555 timer circuit to simulate the actual oscillator.

作者在文中应用PSPICE对555定时器构成的施密特触发器、单稳态触发器和多谐振荡器的工作特性进行了仿真分析和研究，针对PSPICE中555定时器构成的多谐振荡器不起振的问题提出了模拟振荡电路的有效起振方法，对电子电路的分析与设计具有一定的参考意义。

The traditional monostable time delay circuit has to be connected to an exterior RC, resulting in bad accuracy and instability.

传统的单稳延时电路需外接RC支路，故精度不高，稳定性差，预置不直观。

The system consists of a multi-reflection spherical cavity and is suitable for different kinds of specimen,such as concave mirrors,convex mirrors and plane mirrors.

通过积分球和补偿电路，大大地降低了对机械部件的加工要求和激光强度不稳给测量带来的影响。

Aimed at the problem of choosing the initial value when the Newton method is used to compute the controlling unstable equilibrium point, a practical and rigorous solving scheme was presented: by identifying the controlling load bus of the given fault, and using the Thevenin equivalent circuit to represent the rest of the system at the state of the post disturbance stable equilibrium point, using the steady equivalent circuit to represent the induction motor in composite load, and then using the torque characteristics of induction motor, a point near the CUEP is gained to be the initial value. The second order normal forms was used to approximate the stable manifold of CUEP, and the local approximating boundary of the region of attraction of the post disturbance stable equilibrium point was gained. Then just by simulating the state of the system at the fault clearing time, the transient voltage stability of the system could be determined.

针对采用牛顿法求取故障后系统主导不稳定平衡点(controlling unstable equilibrium point，CUEP)存在的初值选取难题，提出一种实用但不失严谨的解决方案：通过识别给定故障的主导负荷母线，对主导负荷母线以外系统由故障后稳定平衡点处的状态进行戴维南等值，对负荷中感应电动机部分采用其稳态等值电路，再由感应电动机的转矩特性求得CUEP附近的一个点作为近似的CUEP，以此为迭代初值可靠求得CUEP；采用二阶正规型来近似CUEP的稳定流形的方法求得近似的局部吸引域边界；由仿真得到故障清除时刻系统的状态并根据该状态是否位于吸引域内判断系统的暂态电压稳定性。

Thirdly, A new topology of Single Stage Asymmetrical Half-Bridge Converter with Synchronous Rectification is presented in this paper. The operation principle of the circuit is analyzed in detail. The operation principle of soft-switching and steady-state analysis is proposed.

提出了一种同步整流单级不对称半桥变换电路，对电路的工作原理作了详细的分析，特别是电路的软开关工作过程，并对电路做了稳态分析； 4。

So far, there is no ASSR system designed by our country, and all the ASSR systems are imported from abroad, which are expensive, and not convenient for spread. In addition, their hardware systems are too complex to repair and adjust. Hence, this paper designs an embedded ASSR system based on DSP in order to fill the gaps in this area.

目前我国还没有自主研发的多频稳态测试仪，都是从国外进口，价格昂贵，不便于推广，而且硬件电路复杂，不易维修和调试，因此本课题设计了基于DSP的嵌入式ASSR听力检测仪，能够填补国内在这方面的空白。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了