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The entire flight process is the rocket's flight mechanics and celestial mechanics of the process, and sometimes is a typical rocket flight mechanics problems, and sometimes is a typical celestial mechanics problems.

整个飞行过程是火箭飞行力学与天体力学的过程，有时是典型的火箭飞行力学问题，有时是典型的天体力学问题。

The key problems of peasants in China today have been become problems of right centering on equal right.

当代中国农民的根本问题已经凸显为以"平等权"为核心的权利问题。

Of course, we still have problems, the central and local relations, we still have problems.

当然，我们仍然有问题，中央和地方的关系，我们仍然有问题。

One method is to change the problems of estimating complex two-dimension sinusoids into the problems of estimating characteristic polynomial coefficients.

一种方法是将复杂的二维正弦波参数估计问题巧妙地转换成一个特征多项式系数估计问题。

Traffic flow has a characteristic of time series. Similarity measurement is one of the important problems in time series clustering problems.

交通流数据具有时间序列特征，相似性度量问题是时间序列聚类中的最基本的问题之一。

The majority of chiropractic work is related to back and neck problems, and treatment is usually more effective for short-term problems than for longer-term conditions.

大多数脊医的工作是有关的背部和颈部的问题，和治疗通常是更有效的短期问题较长期的条件。

Later, it makes some comparison with four kinds of modulation technique, and finally, it implements the three-level PWM switching power amplifier with the PWM technique. The power of the amplifier is 2kVA, and the frequency bandwidth is 10～3kHz. In the thesis, the author designs and makes the hardwares of the switching power amplifier. The hardwares contain power inverter rank circuit, control system circuit based on DSP, drive and isolation circuit, and protective circuit. The thesis also analyses the potential safety problems and put forward some solutions for the problems. Furthermore, the thesis accomplishes the software design of the control system, and successfully debugs it. The methods of designing higher power ampilfier are also discussed in the thesis. It analyses the feasibility of the methods, outlines the way of how to design higher power switching power amplifier, and does some experiments with the method of switches-parallelling.

根据电动振动试验系统对开关功放的要求，提出了以电感电流瞬时值控制技术为基础的三电平脉宽调制开关功放的设计方案，并通过系统仿真进行了原理性论证；然后设计并制作了开关功放的硬件，包括功率转换电路，基于DSP的控制电路，驱动、隔离电路以及保护电路；针对开关功放数学模型不易得出的特点，细致分析了模糊自适应PID控制方法，在此基础上编写了控制程序；研制出一台功率为2kVA，通频带为10～3kHz的三电平脉宽调制开关功放；论文中还探讨了实现大功率开关功放的方法，分析了各种方法的可行性，给出了实现大功率开关功放的思路，并进行了并联开关管实现大功率开关功放的实验。

A fast algorithm for calculating the inverse and Moore-Penrose inverse of the permutation factor circulant matrix is presented. Then, a fast algorithm for the product of the permutation factor circulant matrix is given. Finally, The least-square solutions of inverse problems and the optimal approximation problems for the permutation factor circulant matrix are discussed.

首先给出了一种求n阶置换因子循环矩阵的逆阵、自反g-逆、群逆、Moore-Penrose逆的快速算法，然后给出了计算两n阶置换因子循环矩阵之乘积阵的一种快速算法，最后给出了其反问题的最小二乘解的存在性定理及它的一般表示，并证明了逼近矩阵的存在唯一性且给出它的具体表达式。

By exploiting the special structure of symmetric circulant system, the problems of solution of these systems can be simplified to change the problems of lower dimension systems.

研究具有对称循环结构的广义大系统Lyapunov方程和Riccati方程的求解化简问题，利用简化的解求得复杂系统的最优控制问题。

The author will circumfuse these problems to research the self-defense and try to settle these problems by the means of justice.

因此，本文将围绕着上述几个问题，从学理角度和司法实践中遇到问题进行探讨。

Many will continue to choose to live in duality and in conflict.

许多人将继续选择活在二元对立性和冲突中。

I find that students of the University of Physical Education all wear sportswear at first sight.

我发现：体育大学的学生乍一看，都是穿运动衣，大家都一样