数值方程

In this article two functional modes of the Fly-back Converter (Continuous Conduct Mode and Discontinuous Conduct Mode) are particularly analyzed, which include their characteristics, applications, the critical pattern of two functional modes is argued, both the exact boundary from the angle of circuit parameters is crystallized, at the same time, basic principle of PFC under the DCM mode is introduced, which settle theoretical basis for the subsequent design; by establishing the mathematic model of the converter, a further investigation of the configuration is made, qualitatively and quantitatively, analyzed to settle exactly theoretical basis for the subsequent emulation and the experimental parameter; from the angle of steady-state analysis, the transfer function of the system is deduced to establish dynamic small-signal state equation, emulating the system with the help of matlab, then according to the simulation result and the theory of PFC revise the system, lastly, we adopt the project which add a zero-pole compensator to the voltage loop, by this way, a satisfied system performance is gained and the PFC scheme is ensured successfully; finally, based on the previously-done work, we combining with the situation of specific design requirement, acquired the numerical value of each unit devices in this converter

详细分析了反激式变换器的两种工作状态，连续模式(Continuous Conduct Mode ，简称CCM)和断续模式(Discontinuous Conduct Mode，简称DCM)以及各自的特点、应用场合，论证了两种工作状态的临界模式，从电路参数的角度明确了二者的界限，同时还介绍了DCM模式下PFC的基本原理，为后面的设计奠定理论基础；通过对整个变换器系统建立准确的数学模型，对此变换器的电路结构做了进一步的研究，定性、定量地分析了变换器各部分的工作状态，为仿真和实验参数的确定以及电路参数的优化提供理论依据；从稳态分析的角度，为系统建立了动态小信号状态方程并推导出系统的传递函数，利用matlab对系统进行仿真，进而根据仿真结果以及PFC的相关理论对系统进行校正，采用在电压环加入零点—极点补偿器的设计方案，得到了满意的系统特性并且保证了PFC的顺利实现；最后，在前面所做工作的基础上，结合设计要求计算出此变换器系统中每个元器件的数值，利用Pspice对其进行了仿真、优化，然后根据仿真结果搭建了硬件电路。

The propagation equation of Gaussian pulse is theoretical derived considering second-,third-,fourth-order dispersion.The influence of FOD on propagation properties of femtosecond Gaussion pulse in Single-mode optical fiber is mostly considered.

推导了考虑二、三、四阶色散的高斯脉冲传输方程；利用计算机数值模拟的方法，研究了四阶色散对飞秒高斯脉冲在单模光纤中传输特性的影响。

in order to simplify a process of getting parameters of daubechies biorthonormal wavelet, according to the fourier cosine transform of scale equation of daubechies biorthonormal wavelet, an algorithm is proposed when the daubechies biorthonormal wavelet has even symmetry double scale parameters.

摘 要：为简化daubechies双正交小波因数的求解，以紧支集daubechies正交小波中尺度关系的fourier变换余弦形式为基础，提出1种当双尺度因数为偶对称时，推导daubechies双正交小波对偶尺度方程因数的方法，并给出构造数值实例。

And a model of layer—disperising dual medium is established (2) Some new theories and methods, such as Fourier dual integral transformation and half numeral value analytic method and so on, are used to establish the calculating formula in this paper.

2本文在理论推导上，应用了数学、力学和数学物理方程方面的新理论和新方法，如：二重富里叶积分变换、板壳理论、分离变量法以及半解析数值方法等，使本论文在理论推导过程上，增加了理论的严密性和逻辑性。

Satisfactory numerical validation is presented including a preliminary investigation of time step effect and the value of fractional derivative order for different types of fractional differential equations.

数值算例对不同的分数阶微分方程进行了讨论，探讨了不同的分数阶和时间步长对计算结果的影响，并将计算结果与文献中相关算法的计算结果进行了比较。

The method can beused to solve the integro-differential equation included fractional integral orfractional derivative in a long history and the difficulty of storing all history data isovercome and the error can be controlled.Two numerical examples are presented.

利用该方法可对包含分数积分和微分的积分-微分方程进行较长时间的数值模拟，克服了存储全部历史数据的困难，并能对计算误差进行控制。

Through building Simulink model, the numerical solution of fractional order nonlinear calculus equation can be obtained directly.

通过Simulink搭建仿真框图，可以直接求出分数阶非线性微积分方程的数值解析解。

Second, based on the proposed weak formulation, we investigate the numerical solutionsof the time fractional diffusion equation.

基于上述弱解理论，我们计算时间分数阶扩散方程的数值解。

Fractional Fourier transform procedures for the solution of fractional order equation provided some numerical method.

详细说明：分数阶Fourier变换程序，为求解分数阶方程提供了一些数值解法。

In Chapter 4, we consider more complex fractional nonlinear differential equation,also using the high order approximation presented by Lubich to construct correspond-ing numerical scheme and giving the error analysis of the algorithms.

在第四章中，进一步的考虑更复杂的非线性分数阶常微分方程，同样利用的是Lubich提出分数阶导数的高阶近似，构造相应的数值格式，并给出这一算法的误差分析，即相容性，收敛性和稳定性的证明。

For a big chunk of credit-card losses; the number of filings (and thus charge-off rates) would be rising again, whether

年美国个人破产法的一个改动使得破产登记急速下降，而后引起了信用卡大规模的亏损。

Eph. 4:23 And that you be renewed in the spirit of your mind

弗四23 而在你们心思的灵里得以更新