散射理论

Our main work is as follows: the stable laser mode theory in uniform plasmas is extended to non-uniform plasma cases; the discussion of the sufficient and necessary conditions for laser self-focusing in uniform plasmas is developed to non-uniform plasma cases; a quantitative approach to judge the impact of different plasma density distribution on laser self-focusing is proposed; the evolution properties of asymmetric laser filed in non-uniform and uniform plasmas are discussed and mechanisms that symmetric channel-like plasmas can confine the laser centroid around the plasma channel axes and symmetrize initially asymmetric laser beams are proposed; the formation of solitary standing wave in moderate plasma density is studied by PIC simulations and can be explained by stimulated Raman scattering of laser beams in plasmas.

主要工作为：把均匀等离子体中激光的稳定模理论推广到横向非均匀等离子体情形；把均匀等离子体中激光自聚焦的充分和必要条件的讨论推广到横向非均匀等离子体情形；给出横向密度分布不同的等离子体影响激光自聚焦的定量判据。讨论了初始不对称的激光场在横向非均匀及均匀等离子体中的演化特性，并提出了具有对称腔道结构的等离子体箍缩激光质心和对称化初始不对称激光场的物理机制。用粒子模拟讨论了激光场在等离子体中形成孤立驻波的过程，认为前向受激拉曼散射是发生此现象的可能机制。

This paper presents a new theory to explain the synchrotron radiation.

从虚光子的康普顿散射出发，给出了一种对同步辐射进行解释的新理论。

In fact, to obtain the SEM poles is just a problem of searching the zeroes of a transcendental function in complex plane.

我们知道，从理论上计算散射体的极点，实际上归结为在复平面上搜索一个超越函数零点问题。

Using the scattering matrix theory of fiber couplers, the phase differences between each two of the three outputs of the interferometer were deduced when an unideal 3×3 coupler was used.

由光纤耦合器的散射矩阵理论，推导出了当3×3耦合器分光比不均匀时，干涉仪三路输出信号相位差的表达式。

So, in this paper, a circular cavity witha large radius is used to replace the straight boundary of thehalf space, then the half space problem can be changed tothe scattering problem of two circular cavities to the steadyincident P-wave . Having the aid of the mature cylinderfunction theory, the general solutions of the wave functionscan be given, and an infinite linear algebraic equations ofthe unknown coefficients in the wave functions can be gottenwith the boundary conditions and the Fourier complex seriesexpansion technology, the infinite linear algebraic equationscan be approximately solved by the finite trunction withsatisfying some definite precision, at the basis of thissolution of the equation, the variations and the lay-outs ofthe DSCF at the circular cavity boundary vs. the differentincident angles, the different embedded depths of thecircular cavity as well as the different dimensionless wavenumber of the incident P-wave.

为此，本文采用一个半径很大的圆孔来代替半空间的直边界，将该半空间问题转化为一无限大空间中两个圆孔对稳态P波的共同散射问题，借助于成熟的柱函数理论，通过写出问题波函数的一般形式解，利用问题的边界条件，并采用复数傅立叶级数展开技术将其化为一个仅包含问题波函数中未知系数的一无穷线性代数方程组，在满足一定计算精度的前提下，通过有限项截断进行近似求解，进而讨论了圆孔边界处的动应力集中系数随不同入射角、不同的圆孔掩埋深度、入射波的不同无量纲波数以及介质的泊松比变化和分布情况。

Based on the optoelectronics theory, the experiment device is designed, which is composed of pulse generator, LD light source, 1×3DQ, adjustable CTB, testing optic fiber, intervening light filters, fast micro-light watt-meter and data analysis system. The technology of optic fiber Raman scattering is analyzed for its application to temperature testing of railway engineering.

根据光电子理论，设计由脉冲发生器、LD光源、1×3路双工器、可控恒温槽、光纤、干涉型波分复用器、快速微光功率计和数据采集分析系统组成的实验装置，进行光纤喇曼散射技术用于铁道工程构筑物温度的监测研究。

By using the continuity equation and weak hydrody-namic interaction theory in the relaxation time approximation, the spatial variation of the radar scattering cross-sec-tion has been proved as proportional to the gradient of current velocity.

在浅海海流速度垂直分布廓线为均匀的假定下，由流体连续性方程和弛豫时间近似下流体力学弱相互作用的理论，已证明雷达散射截面的空间变化正比于海流方向上海流速度变化的梯度。

Firstly, the target vector is transformed to the state with minimization of cross-polarization; then the parameters u/v/H are used to characterized scattering mechanism, and the fuzzy membership is adopted instead of "hard" division of parameter plan; finally, characterizing the coherency matrix as multivariable complex Wishart distribution, the polarimetric SAR image is classified based on Bayes maximum likelihood criteria.

该文提出了一种新的非监督分类算法，该算法首先根据去取向理论，将目标向量旋转到最小交叉极化方向；然后，采用u/v/H参数描述散射机制，以模糊隶属函数代替参数平面的"硬"阈值划分；最后，以多元复Wishart分布描述相干矩阵，基于Bayes极大似然分类准则进行分类。

Based on the theory of stimulated polariton scattering, adopting reported experimental conditions that generate tuning terahertz wave utilizing nonlinear optical parametric oscillation as the theoretical analysis model, taking GaAs, GaP, InP, ZnTe crystal as representative, the absorption and gain characteristics in zinc blende crystal are calculated, and the output tuning characteristics of terahertz wave are also analyzed.

基于受激电磁耦子散射原理，采用已报道的利用非线性光学参量振荡方法产生可调谐太赫兹波的实验条件作为理论分析的实验模型，以GaAs、GaP、 InP、ZnTe晶体为代表，计算分析了在闪锌矿晶体中参量振荡产生太赫兹波的吸收、增益特性，对输出THz波的调谐特性给出了详尽分析。

Both the scattering and rheological results indicated that the phenomenon similar to"double cloud point", which has been found along the vorticity direction by previous studies, could be also observed in the velocity direction, which confirms the prediction of the above theory that the polymer blend will exhibit anisotropical complex phase diagram under shear. It's also found that the mixing along vorticity direction was reduced by weak shear but enhanced by strong shear. In addition, the more remarkable the molecular weight differences between components, the more prominent the shift of the apparent phase boundary along vorticity direction.

除了以往研究发现涡流方向存在&双浊点&现象以外在，本文的光散射和流变测试均显示，剪切场下体系在流动方向上也出现了类似&双浊点&的现象，证实了上述理论模型关于剪切场会导致二元高聚物共混体系出现各向异性的复杂表观相图（例如Miscibility Gap现象）的预测；同时发现弱剪切会导致体系涡流方向上的相容性减小，而强剪切则在该方向上增强相容性；另外，两组分分子量的差异越大，表观相界的移动越显著。

In the negative and interrogative forms, of course, this is identical to the non-emphatic forms.

。但是，在否定句或疑问句里，这种带有"do"的方法表达的效果却没有什么强调的意思。

Go down on one's knees;kneel down

屈膝跪下。。。下跪祈祷