冲击波

Nonlinear flexural wave equation is solved by the Jacobi elliptic function expansion method. Two kinds of exact periodic solutions of the nonlinear equations are obtained, that is, the shock wave solution and the solitary wave solution. The necessary condition for existence of exact periodic solutions, shock solution and solitary solution is discussed, which is consistent with the qualitative analysis.

利用Jacobi椭圆函数展开法，对该非线性方程进行求解，得到了非线性波动方程的准确周期解及相对应的孤波解和冲击波解，讨论了这些解存在的必要条件，这与定性分析的结果完全相同。

The XRD results were just the same as previous researches, which indicated that the main phase of the recovered samples is not perovskite structure, but single-chain structure enstatite. Especially, no evidence of the oxides SiO_2 and Mg_(0.92, Fe_(0.08) O in recovered samples was observed.

在78～115 GPa冲击压力(估算温度为3000～5000K)范围内进行了两发原始样品为Mg_(0.92，Fe_(0.08)SiO_3顽火辉石+铁的冲击压缩回收实验，这是国际上首次采用冲击波回收技术来研究铁与硅酸盐的反应，是本文的又一创新实验设计。

The vapour and plasma ignition times of the target are got based on the equation of heat conduction and cascade model. We suppose that the plasma is ignited when 210 generations of new electrons are born in vapour generation time. The influence of temperature on the thermodynamics and optics parameters of material also have been considered in the model. The resulting theory has good agreement with the experiment and overseas report. A blade method to measure the laser spot is given in this paper with validation and error analysis. The plasma threshold of metals in atmosphere and water ambients both are diagnosed with the light deflection and piezoelectric transducer. A Q-switched pulsed Nd:YAG laser operating at infrared (1064nm), visible(532nm) and ultraviolet (355nm) wavelengths has been used. Al、Fe、Cu are used as targets and get a similar results with both method. Theoretical and experimental analyses are applied on the influence of wavelength on the threshold have been done, both of which have shown that the plasma threshold of metals decrease as the laser wavelength increases; The plasma threshold of metals are higher in water than in air and the pressure of the shock wave in water is five times higher than in air.

从热传导方程和雪崩电离机制出发，假设当电子增值2~(10)倍时，考虑了温度对材料热力学和光学参数的影响时，得到了气化和等离子体点燃的时间，利用该模型进行计算得到的结果与国内外报道及自行通过实验测得的阈值基本一致；提出了利用刀刃法测量激光光斑面积的方法，并通过实验进行了验证和误差分析；利用光偏转装置和压电换能器分别对空气和水中金属等离子体点燃阈值进行了实验诊断，激光器均为调Q—YAG激光器(波长1064nm，532nm，355nm，脉宽10ns)，靶材分别为Al、Fe和Cu，两种测试方法得到的等离子体点燃阈值基本一致；本文从实验和理论计算两个方面讨论了波长对等离子体点燃阈值的影响，均得到了等离子体点燃阈值随着波长的增加而减小的结论；对空气中和水中不同环境下金属等离子体的点燃阈值进行了比较研究，得到了金属在水中的等离子体点燃阈值比空气中的大，且水中产生的冲击波的压强是空气中的5倍左右的结论。

The main point of the improvement is adding a circuit branch with an etalon resistance connected in series in it , for monitoring the shock-wave arrival time entering the sample, in the measuring electrical circuit .

Mitchell等的测量冲击压缩下绝缘材料电阻率的技术做了改进，其主要之点是，在测量电路中增加了一个记录冲击波进入试件的电支路，并在新支路中串接一个基准电阻。

The main point of the improvement is adding a circuit branch with an etalon resistance connected in series in it , for monitoring the shock-wave arrival time entering the sample, in the measuring electrical circuit.

这样做的好处是：(1)便于提高试件电阻信号的电平，或提高试件电阻的可测上限范围；(2)可以用基准电阻的实测值对试件的实测电阻值进行校核；(3)可以同时测得试件中的冲击波速度值。

The computation results agree with the experiment results very well. The muzzle flow field of an artillery with a muzzle brake is also simulated. The main characteristics and the mutual relations of shock waves in the muzzle flow field are obtained by the simulation. On the basis of the simulation results, the influences of the brake holes on the muzzle brake capabilities are analyzed.

对某口径火炮带有制退器的膛口流场进行了数值模拟，其结果反映了制退器内外流场的主要特征和冲击波波系之间的相互作用，在数值模拟的基础上分析了3排侧孔对制退器性能的影响。

The above image captures much of that filamentary and gigantic shock in visible light, spanning almost 100 light years and appearing twenty times the diameter of the full moon.

上面的影像显示了在可见光线下捕捉到了一些灯丝状物质，以及巨大的冲击波，影像大约覆盖了100光年，看起来是满月直径的20倍。

I was dazed, but fortunately I had my helmet and flak jacket on, and they absorbed a lot of the shock wave.

我神情恍惚，幸好头盔和炮衣吸收了大部分冲击波。

However, the "impact" of the Far South Games foreshadow s a bright future for this civilized and progressive cause

但是，远南运动会掀起的"冲击波"，预示着这项文明、进步的事业前景是美好的。

Buns fat blaster - Get tight, tone buns in only 10 minutes!

馒头发冲击波-获取紧仅10分钟，调包！

In the United States, chronic alcoholism and hepatitis C are the most common ones.

在美国，慢性酒精中毒，肝炎是最常见的。

If you have any questions, you can contact me anytime.

如果有任何问题，你可以随时联系我。