阶矩

The parameters of the model are fuzzily processed and the fuzzy risk can be evaluated by using the modified first order second moment method.

通过对模型中的参数进行模糊化处理，用改进一次二阶矩法计算了地下水过量开采的模糊风险率。

Thus, the physicomathematical model is established to describe the combustion and flow behavior inside the combustion chamber, the second combustion chamber and the nozzle of the solid fuel ramjet.

采用二阶矩湍流燃烧模型，有效克服了常用的E—A模型、简化PDF模型等均无法正确描述固体燃料冲压发动机中化学反应速率和扩散速率处于同一量级的现象。

The random errors of main factors in flood regulation process are identified; and combining flood forecast, the randomnesses of main parameters such as initial reservoir level, inflow flood, outflow flood, etc., are analyzed. By using the first order second moment method and theoretic distribution, the random distributions of parameters are described then the routing process of a certain preflood limit water level is random, which can well reflect the random preflood influences in actual regulation.

对防洪调度过程各主要相关参数进行了随机误差识别，结合洪水预报对起始水位、人库洪水、泄流等主要参数的随机性进行分析，应用一次二阶矩法和相应的理论分布函数描述事件的随机分布，对应某一汛限水位的调洪过程不再是一确定过程，而是具有随机分布特性，反映了实际防洪调度中各随机因素的影响作用。

Reynold Stress Model can enhance the calculating precision.

结果表明二阶矩的雷诺应力模型能提高模拟精度。

Second, in this thesis we discuss how to make OFDM system combats with time selective channel.

当移动速度增加时，多普勒谱的四阶矩也增加，随之时间轴上的导频密度x_1应该减小。

The stereo image pair is acquired by a pair of calibrated cameras. Global disparity of foot is estimated at first. After the image pair is preprocessed automatically, using non-contact information-collecting technique and phase-correlation method, which is based on complex wavelet, surface matching with sub-pixel accuracy in the frequency domain is carried out. By taking order matching constraint, continuity constraint and correlation constraint together, 3D point cloud of foot is reconstructed and 3D model of foot is built by mosaicking point cloud at various angles automatically. After normalization, high-order moments are compared, which is useful for the subsequent shoe last design.

运用已标定的双目照相机拍摄立体图像对，进行足部整体视差估计；在对立体图像对进行自动预处理后，采用非接触式的信息采集技术，运用基于复小波的相位相关技术对足部表面进行亚像素级小区域频域匹配，考虑顺序匹配约束、连续性约束和相关性约束条件，重建足部密集三维点云信息，并自动拼接不同角度点云生成相应的足部三维模型；对其归一化后，提取其高阶矩向量进行比对，为后续的三维鞋楦设计提供必要信息。

The divergence angle of light beam was measured with the method of CCD imaging and computed by second moment method.

通过CCD成像方法对准直后的光束发散角进行了测量，利用二阶矩算法计算出光束发散角。

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 calculation results indicate that the first order metho...

计算结果表明，基于响应面法的一次二阶矩法具有较好的计算精度。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。