Principal conclusions were drawn as the following : the non compatibility of pressure or velocity of the gas on both sides of the contact surface is the cause of the formation of shock wave ; the heating effect of reflective shock wave to driving gas during charging or exhausting process is the internal mechanism of peak oscillating effect , and all the factors that influence the formation and the running of the shock wave will influence the peak oscillating frequency , cooling effect 主要结论如下：热分离机内激波形成的原因是射气瞬间接触面两侧压力和速度不相容；峰值振荡效应的内在机制为反射激波对充气阶段的驱动气或低温排气的加热，凡是影响激波形成及运动的因素都将对峰值振荡频率、冷效应及热效应产生影响；当充、排气时间比为0 . 1763时，最佳射流激励频率出现在高阶峰值振荡频率上。
This paper carry out power system post - stability analysis with eurostag . this paper determine the state after low frequency oscillation according to the relation between oscillation frequency of low frequency oscillation and eigen value of small signal analysis , which is derived from a great deal of simulation projects . cai xiaoling ( power system and its automation ) directed by prof 利用eurostag进行电力系统后稳定分析，针对低频振荡引起的后稳定问题，通过大量仿真研究了小扰动特征值分析结果和大扰动振荡频率之间的关系，并据此判断系统发生低频振荡失稳后的状态，为将来进行后稳定后续分析打好基础。
A 3rd generation converter samples the signal 44 , 100 times per second - with a frequency of 44 . 1 khz kilohertz . this time resolution exceedingly determines the sound , which we finally perceive : a low resolution sampling or sample rate results in a more muffled sound because quickly oscillating sound waves i . e . high tone are not acquired correctly 读取频率，也就是声音的采样频率，的高低直接影响到我们最后所听到的声音，如果采样频率不够高，听到的声音会感觉有点糊糊的暗暗的，因为没有办法读取到某些振荡频率较高的声波，也就是高音的部分。
With time - evolution - operator , it is proved that the population of upper level is in circumstance of cyclic oscillation by laser pulses pair of gaussian line - shape in a homogeneous broadening two - level system . the oscillatory time oxide is the delay time between the laser pulse pairs and the oscillatory frequency equals the one of transition between the lower and upper level 引入时间演化算符，证明均匀增宽二能级体系在飞秒激光脉冲对作用下上能级激发态布居是周期性变化的，它以飞秒脉冲对之间的延时为时间轴，以该原子能级之间的跃迁频率为振荡频率
This instrument keeps constant temperature by circling air both . it use computer to control temperature and oscillation frequency , led digital display , it has stable performance , and its quality is reliable , its appearance is beautiful and digniful . it can be operated conveniently . it is the suitable instrument uhcih is used on researching and production by the trades of bioengineering . medicine . hygienist and so on 该振荡培养箱是利用旋转空气浴进行恒温的振荡器,温度和振荡频率均采用电脑控制,用led数码显示.该振荡器性能稳定,质量可靠,造型美观大方,操作方便,实为生物工程、医药、卫生等行业科研和生产中使用的理想仪器。
A full - digital demodulation technique is introduced in this paper , which can make it easy and quick to design and achieve binary phase shift keying ( bpsk ) demodulator , and also can reduce the requirement of the oscillator frequency precision and the degree of stability of the receiver 本文介绍了一种适合于用数字信号处理器( dsp )实现的全数字解调技术。该技术能方便、灵活地设计实现二进制相移键控( bpsk )解调器，而且使用该技术可以大大降低对接收机本身的振荡频率精度和稳定度的要求。
Because quasi - fermi levels of a laser diode ( ld ) vary with the carrier density , it is predicted that a new type of hysteresis loop should occur for the current passing ld while a hysteresis loop appears on the power - frequency curve of the ecld . an explicit analytical expression for the frequency width of the hysteresis loop and the condition for the formation of the hysreresis loop has been deduced 预测了由于半导体激光二极管( ld )的准费米能级之差随ld内线流子密度的变化而变化，因而，在调谐外腔半导体激光器的输出功率?振荡频率曲线上出现双稳环的时候，通过ld的电流也应出现一个伴随的新型双稳环? ?电流双稳环。
A square sensing area was formed upon each of the saw propagation paths using photoresist . when some kind of material deposits on this area , the saw propagation velocity will decrease due to the mass - loading effect , causing a shift in the device ' s oscillation frequency , which gives indication of the mass deposited . the dual - path architecture , one for sensing and one for reference , was used to compensate for the disturbance of temperature 利用光刻工艺在每个声传播路径上构造了一个方形质量沉积区，当有物质沉积到该区时，由于质量沉积效应，声表面波的波速发生变化，使以延迟线作为反馈回路的振荡器的振荡频率发生变化，并通过这一变化反映出沉积物的质量。
Simulation results show 2 . 5 gw output power with a frequency of 1 . 25ghz can be generated with an input of 620kv voltage , dc input power of 10 . 5gw electron beam . ( 3 ) the radial reflex klystron with an open foldaway - concentric cylindrical resonant cavity integrates the resonant cavity and reflex cavity within one foldaway coaxial cavity , so it is a very compact high power microwave device 然后对这种器件进行了数值模拟研究，得到的典型结果为:输入电压620kv ，输入直流功率io . sgw ，输出微波峰值功率为2 . sgw ，虚阴极振荡频率被锁定，频率为1 . 25ghz ，微波饱和时间小于sns 。
This method makes it possible for investigating the unsteady nonlinear potential flow in a complicated environment with higher efficiency . the aerodynamic forces of a wing in couple motion of heave and pitch with ground effect are analyzed in detail based on the numerical result . it is shown that a thrust force exists when the wing is in heave motion 深入系统地分析了存在表面效应时机翼运动规律和气动力之间的关系，研究结果表明，机翼升沉运动产生的推力与升沉速度幅值的平方成比例，推力和推进效率和振荡频率成反比；机翼的俯仰运动可以调节推力和推进效率，但是单纯的俯仰运动不会产生推力。
