波

In this paper , we introduce clutters scatter characteristics at first and sum up model of scatter coefficient probability distribute model and clutter correlated characteristics model, show two basis method of simulation.

本文首先介绍了杂波的散射特性，并在此基础上总结了杂波模拟时所需要的后向散射系数模型，杂波的概率分布模型和杂波相关特性模型，给出了两种杂波模拟的基本方法。

Based on the conclusion, we adopt a new method to eliminate multiples, which is to use the statistic character of error, obtain inverse wavelet's estimation, correct misshaped inverse wavelets for non-orthogonality in inverse wavelet domain by the estimation. The method mainly has four steps.

在此基础上，本文提出了在逆子波域（单道自适应相减滤波的滤波算子的集合），利用其误差的概率分布特征，对逆子波进行估计，用逆子波的估计对逆子波进行校正来消除多次波的方法。

The results are verified from deep to extremely shallow water conditions. The shoaling waves, standing waves, 3D disturbance waves, tidal waves and solitude waves are simulated and verified,and waves over an underwater bar,the diffraction near single breakwater, breakwater gap, offshore breakwater, Breakhoff experiment are taken into account in this model. Furthermore, the wave harbor resonance under special topography, and "Bragg" resonance are simulated. The wave refraction problem under current fields,the nonlinear wave refraction-diffraction under "Arthur" current field, and the wave propagation under slowly varying current field are studied. The favorable calibrations show the model's feasibility in dealing with the wave nonlinearity and simulation in both deep and shallow water.

论文对深水至极浅水非线性波进行了较全面的验证，计算模拟了波浪浅化、立波、三维干涉波、潮波、孤立波以及波浪越过潜堤、单突堤绕射、双突堤绕射、岛式堤、Berkhoff实验和多连通水域波浪传播等问题，还对特殊地形条件下波浪发生港湾共振、布拉格共振进行了仿真；论文研究了水流中波浪传播折射变形问题，Arthur流场上非线性折射-绕射、水位缓变的转向潮流中波浪传播等缓变水流中波浪问题，各类问题的较好解决验证和表明了本文模式与方法具有适用于深浅水的可计算性与非线性。

Based on the fact that the different modes of Rayleigh wave have different propagation velocities, the signals of Rayleigh wave which superposes in time domain can be separated in frequency-wave-number domain, different modes of Rayleigh wave are separated and extracted by Fourier transform.

摘 要：应用Fourier变换法分离提取地震记录中不同模态的瑞雷面波，其原理是：利用瑞雷面波各模式传播速度的差异，将时间域中叠加在一起的瑞雷面波信号在频率波数域中分开，以此实现分离提取各阶模态瑞雷面波。

The earliest change of ERG in birdshot chorioretinopathy was the prolongation of cone ERG implicit time. Followed by the decrease of dark-adapted b wave amplitude. The b wave amplitude of cone ERG decreased later. The duration of the disease correlates with the amplitude of b wave in the same patient. The a wave was the last affected and the decrease of the a wave amplitude was disproportionate compared to that of b wave, revealing a typical negative type ERG.

结果发现最早的变化为锥细胞ERG潜伏期的延长；接着是暗适应b波振幅下降，锥细胞b波下降较晚，同一患者病程的长短和ERG b波振幅下降幅度一致；a波振幅下降晚于b波，且下降不成比例，出现负相ERG，可作为诊断此疾病的特征性ERG。

The numerical result shows that this method can correctly and quickly separate pure compress wave and pure shear wave from hybrid wave field with high precision, good boundary absorption, and the numerical process is stable, so it can be used to guide multi-wave multi-components seismic datum processing, and also point out that the method has difficulty to separate the coupled wave type such as surface wave.

数值模拟结果表明，该方法能够从混合波场中准确地分离出纯纵横波波场，且精度高，边界吸收效果好，计算速度快，计算过程稳定，可用于指导实际多波多分量地震资料处理，同时指出本文算法对相互耦合的波型无法实现准确分离。

To improve the conventional difference threshold algorithm.

该文对QRS波群的检测算法进行了研究，对传统差分阈值法在R波检测中存在的一些问题加以改进，将正向和倒置R波分开检测，提出了在自适应差分阈值法检测正向R波的基础上，用幅值基线比较法检测倒置R波的检测方法。

This problem is also important and valuable in Nonlinear Optics. It will be very helpful to understand how the aberrations affect the course of three- wave mixing, such as the change of conversion efficiency, the distribution of intensity and phase.Small signal solution of aberrated second harmonic generation is deduced from three-dimension three wave coupling functions. The numerical work gives out lot of results of different aberrations. The effects of the fundamental waves aberrations, which will change the conversion efficiency, distribution of intensity and phase in the frequency conversion, is analyzed. It shows that when walk-off and diffraction effects could be ignored approximately estimation of the phase distribution of second-harmonic wave could be done. The far field divergent angle and second moment radius of harmonic wave will vary with the aberration of fundamental wave, but the far field divergent angle will be obviously smaller than that of fundamental wave. The phase distribution of both fundamental and harmonic wave is measured using Hartmann-Shack wave front sensor in the experiment with 1064nm and 790nm lasers, respectively. Results are given.

首次从三维三波相互作用方程组推导得到了位相畸变光束倍频的小信号解；通过建立国防科学技术人学研究生院学位论文三维数值模型，编写相应仿真程序，首次得到了位相畸变光束倍频过程的大量计算结果，深入细致地研究了位相畸变光束经非线性光学频率变换后谐波的转换效率、光强分布、位相分布以及影响它们的各种因素；得出谐波的远场发散角和光斑二阶矩的变化规律会因为基波像差的不同而不同，但谐波的远场发散角明显地比相应基波的小的结论；得到了在走离效应和衍射效应等影响许多因素可以忽略的情况下，位相畸变传递到二次谐波的估算式；举例分析了KDP三倍频方案中，基波位相畸变对二次谐波和三次谐波的影响；实验工作中，用哈特曼一夏克传感器分别对IO64nm倍频过程和790飞秒超短脉冲倍频过程中的基波和谐波的位相分布进行了测量，给出了相应结果。

Small signal solution of aberrated second harmonic generation is deduced from three-dimension three wave coupling functions. The numerical work gives out lot of results of different aberrations. The effects of the fundamental wave's aberrations, which will change the conversion efficiency, distribution of intensity and phase in the frequency conversion, is analyzed. It shows that when walk-off and diffraction effects could be ignored approximately estimation of the phase distribution of second-harmonic wave could be done. The far field divergent angle and second moment radius of harmonic wave will vary with the aberration of fundamental wave, but the far field divergent angle will be obviously smaller than that of fundamental wave. The phase distribution of both fundamental and harmonic wave is measured using Hartmann-Shack wave front sensor in the experiment with 1064nm and 790nm lasers, respectively. Results are given.

首次从三维三波相互作用方程组推导得到了位相畸变光束倍频的小信号解；通过建立三维数值模型，编写相应仿真程序，首次得到了位相畸变光束倍频过程的大量计算结果，深入细致地研究了位相畸变光束经非线性光学频率变换后谐波的转换效率、光强分布、位相分布以及影响它们的各种因素；得出谐波的远场发散角和光斑二阶矩的变化规律会因为基波像差的不同而不同，但谐波的远场发散角明显地比相应基波的小的结论；得到了在走离效应和衍射效应等影响许多因素可以忽略的情况下，位相畸变传递到二次谐波的估算式；举例分析了KDP三倍频方案中，基波位相畸变对二次谐波和三次谐波的影响；实验工作中，用哈特曼-夏克传感器分别对1064nm倍频过程和790飞秒超短脉冲倍频过程中的基波和谐波的位相分布进行了测量，给出了相应结果。

The effed Of three-dimensional perturbed velocities and three-dimensional perturbed current densities on the beam-wave interaction of plasma-filled dielectric Cherenkov maser is analysed by use of the self-consistent linear field theory without considering the effect Of the longitudinal guided magnetic field.The dispersion relation and the Simultaneous condition of the beam-wave interaction are derived. It is clearly shown that the instability of the interaction results from the coupling of the TM mode in t...

在无引导磁场的作用下，利用自洽线性场理论，分析了电子的三维扰动速度和三维扰动电流密度对填充等离子体的介质切伦可夫脉塞注波互作用的影响，导出了注波互作用的色散关系和同步条件，所得关系清楚地表明，其工作用不稳定性是由填充等离子体的介质筒慢波波导中的TM模与电子注模通过电子注耦合所致，并求得了电子注引起的频偏和波的增长率。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。