模型理论

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。

In section 4.2, we study the rescaled WLC model which is equivalent to Langer and Singer's theory of elastica because the Gauss curvature equals zero in three-dimensional Euclidean space.

我们首先讨论了Feoli 等人的结果，将之作为自由能仅为曲率的泛函的特例纳入普遍形式理论中来；并研究了Langer 和Singer 提出的关于弹性曲线的理论(即重新标度的WLC模型)，与当前理论符合得很好。

In the first part, first, the operational principle of Varivec Propeller is explained. Secondly, the mathematical model for predicting longitudinal and transverse movement hydrodynamic characteristics of Varivec Propeller under steady or unsteady condition are present, based on the general propeller lifting-surface theory, potential flow theory and Green theorem. Thirdly, theoretical calculation methods for predicting hydrodynamic characteristics when the influence of paraboloidal boss on the performance of Varivec Propeller is or isn't considered are present, based on The finite basic solution method, the unsteady vortex lattice method and Hess-Smith method Different rake angle is adopted according to different desire in practical application.

在理论计算部分，本文首先给出了全方向推进器的工作原理，然后基于常规螺旋桨升力面理论、势流理论和格林定理建立了定常和非定常状态下全方向推进器纵向、横向运动的水动力性能计算的数学模型，并利用有限基本解法、非定常涡格法和Hess-smith方法分别对考虑和不考虑桨毂影响时的全方向推进器纵向、横向运动水动力性能进行了数值预报。

Firstly, groupthink theory and its relevant research are reviewed and evaluated, and the background of theory development and the general groupthink model are introduced.

文章首先对群体思维研究的相关理论进行了回顾和评述，介绍了群体思维理论发展的一些背景，并给出了群体思维的一般理论分析模型。

About the stability analysis of railway vehicle system has been discussed for years. In reference reviews, we will introduce all about these theories, including linear and nonlinear theories. Finding out these theories, and improving the inconsequent assumptions.

关於轨道车辆的稳定性分析已有多年历史，在本论文文献回顾中将从最早的Hertz理论开始做介绍，逐步探究各理论发展过程，最后介绍Heuristic非线性理论，并藉由改进文献中不合理的假设，套用模型做数据模拟分析与讨论。

Using the Mindlin theory, the four-node finite element shell modal of healthy and damaged structure is formed; Using Green Function theory, the fluid around the structure is considered to be inviscid, irrotational and incompressible, and then the effect of fluid to structure is translated to the added mass matrix compared with global mass matrix using BEM.

基于Mindlin理论，本文建立了描述健康和损伤的四结点有限元板壳单元模型；基于Green函数理论，将结构所处的流体环境考虑为无粘、无旋、不可压缩的理想流体，推导了三维问题拉普拉斯方程的基本解，并利用边界元方法将流体对结构的影响归结为对结构整体质量矩阵的影响；针对各向同性损伤单元，采取刚度各向整体弱化的方法分析；对于各向异性损伤单元，采用Kachanov理论，引入了x和y两个方向的弹性损伤折减系数。

It can solve seismic velocity problem in the area with lateral strong velocity variation. A new method is developed to improve the precision of velocity model building.

从射线理论的程函方程出发，提出了一种没有过多理论条件约束的基于模型全局优化剩余曲率分析速度建模方法，理论和实际资料的计算证明了该方法的有效性。

Firstly, this paper introduce the present and prospective development, moreover compared advantage and short of different roll forming theory. Subsequently simplified process and analyzable model of channel section according to deforming elastic-plastic macro deforming finite element theory.

本文首先介绍了国内外关于辊式冷弯成型理论研究的现状与发展趋势，并比较了各成型理论的优缺点，随后在分析槽钢辊弯成型特点及其变形规律的基础上，以弹塑性大变形有限元理论为基础，对槽钢成型过程做出合理简化，建立分析模型，利用MARC软件对槽钢辊弯成型进行了三维有限元数值模拟分析。

Such as Markowitz"s modern assets portfolio theory, Sharp, Minter and Mossin"s Capital Assets Price Model; Ross"s Arbitrage Pricing Theory; Black-Scholes"s the option of fixes the price classical capital market theories. They are all based on EMH.

例如马克维兹现代资产组合理论，Sharp、Minter、Mossin的资本资产定价模型，罗斯的套利定价理论，Black-Scholes的期权定价公式等经典资本市场理论，都是以有效市场假设为前提的或者与之有密切的联系。

Based on the research of chaos and software requirements complexity theory, a theory model was proposed.

在基于混沌理论和软件需求复杂性理论研究的基础上，提出一种理论模型。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。