Three Dimension Simulation of Millimeter Wave Double Staggered Coupled Cavity Structure

After analyzed the cavity field mean method theory resolution, the software simulation method to obtain the resonance frequency, Q value and RF dispersion by MAFIA and ANSYS software is discussed for the double staggered coupled cavity Millitron structure in the millimeter-wave TWT. The resonance frequency and Q value of the single cavity is obtained and is consistent with two kind of the simulation software. Their average error is about 0.6%. The two kind of the simulation result is consistent to the design precise. The simulation method saves on the cost and time in the experiment, improve the data precise and work efficiency. The trend of the dispersion simulation result is consistent with the cavity field mean method theory result. The high end of the theory result is great contrast to that of MAFIA result. It shows that the theory adopt some hypothetical conditions, But the theory result has some instructional signification in initialization design of the novel slow wave structure.     

水下爆炸冲击波在含吸收层结构中的传播规律的数值模拟

 利用ANSYS/LS-DYNA软件,对水下爆炸冲击波在含有吸收层的多层结构中的传播规律进行了数值模拟。结果表明：冲击波在吸收层中的衰减是由泡沫材料自身的本构引起的;在含泡沫材料吸收层的结构中峰值压力仅为不含吸收层的14%,冲击波传播波形发生改变;在含有泡沫混凝土的多层结构中应力波峰值的下降幅度比含泡沫铝的大,但冲击波传播波形的变化不是很明显;泡沫混凝土中的总能量大于泡沫铝中的总能量,因此泡沫混凝土作为防护吸收层要优于泡沫铝。     

双辉光放电静电场数值模拟及场分布边角效应分析

根据双辉光放电3个电极极板上的电势,利用边界元积分方程建立以面电荷密度为未知量的离散方程,通过求解线性方程组计算3个电极极板上面电荷的不均匀分布.由极板上的不均匀面电荷分布计算在真空状态下空间任意一点的电势和电场的空间分布,利用数值解对真空状态下双辉光离子渗金属实验装置场分布边角效应进行了分析.     

粗糙目标合成孔径激光雷达信号仿真

建立粗糙表面的蒙特卡罗模型,研究目标表面高度起伏对光外差信号的调制效应,对不同粗糙程度的目标引起的退相干效应进行定量分析,给出光外差信号恶化与粗糙目标表面参量的定量关系.结果表明:当相关长度为100λ,光外差信号随着高度起伏均方根的增大而减小,当高度起伏均方根超过0.2λ时,光外差信号非常微弱;当均方根高度起伏为0.1λ时,光外差信号随相关长度的减小而减小,给光外差探测造成困难.     

Fluctuations, response and aging dynamics in a simple glass-forming liquid out of equilibrium

By means of molecular dynamics computer simulations we investigate the out of equilibrium relaxation dynamics of a simple glass former, a binary Lennard-Jones system, after a quench to low temperatures. We find that one-time quantities, such as the energy or the structure factor, show only a weak time dependence. By comparing the out of equilibrium structure factor with equilibrium data we find evidence that during the aging process the system remains in that part of phase space that mode-coupling theory classifies as liquid like. Two-times correlation functions show a strong time and waiting time dependence. For large and times corresponding to the early -relaxation regime the correlators approach the Edwards-Anderson value by means of a power-law in time. For large but fixed values of the relaxation dynamics in the -relaxation regime seems to be independent of the observable and temperature. The -relaxation shows a power-law dependence on time with an exponent which is independent of but depends on the observable. We find that at long times the correlation functions can be expressed as and compute the function h(t). This function is found to show a t-dependence which is a bit stronger than a logarithm and to depend on the observable considered. If the system is quenched to very low temperatures the relaxation dynamics at long times shows fast drops as a function of time. We relate these drops to relatively local rearrangements in which part of the sample relaxes its stress by a collective motion of 50-100 particles. Finally we discuss our measurements of the time dependent response function. We find that at long times the correlation functions and the response are not related by the usual fluctuation dissipation theorem but that this relation is similar to the one found for spin glasses with one step replica symmetry breaking. Received 17 May 1999