结合原理

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 author introduced to design a language for dominant with Visual Basic 6.0, combine Access2003 of tiring-room relation database, build Xinjiang the principle of system of information of database of feral fruiter resource and method, the database technology development that uses the computer goes the complete feral fruiter that can apply extensively at service of fruiter production, scientific research, education, society to wait is planted program of qualitative resource database.

笔者介绍了以Visual Basic 6.0为主导设计语言，结合后台关系数据库Access2003，建立新疆野生果树资源数据库信息系统的原理和方法，运用计算机的数据库技术开发出一套完整的可广泛应用于果树生产、科研、教学、社会服务等的野生果树种质资源数据库程序。

The new method was based on the electrochemical fundamental equations and was combined with coulostatie perturbation techniques, i.e.

该方法以电化学基本方程为基础，结合恒电量微扰技术原理。

This thesis is trying to introduce the fundamental of Haier Group's "Slope Ball" theory into the management of commercial banks, and to do the essential analysis and research according to the characters of commercial banks.

本研究试图将海尔集团"斜坡球"理论的基本原理引入商业银行的经营管理，并结合商业银行的业务特点，进行必要的分析和研究。

In light of the first expressway reinforced gabion retaining wall in China, which reinforced earth engineering of Xiangtan to Hengyang express highway section of K124 +300～K124 +895 in Hunan province, the external stability analysis of reinforced gabion retaining wall was analyzed by using the reliability analysis method and the reliability index and failure probability were given with this method. The results show that this method is simple, scientific and reasonable.

介绍了Rosenblueth矩估计方法的基本原理及其在加筋格宾挡墙外部稳定性分析中的应用，提出了加筋格宾挡墙外部稳定性可靠度分析方法，基于Rosenblueth方法开发了相应计算程序，研究了填料粘聚力c、内摩擦角φ、地震力、填土重度、车辆荷载以及加筋间距等重要参数对可靠度指标的影响，结合我国第一座高速公路加筋格宾挡土墙（湖南省湘潭至衡阳西线高速公路第十二合同段K124+300～K124+89段加筋土工程）运用可靠度理论分析其外部稳定性，得到了该挡墙外部稳定可靠性指标和破坏概率。

Based Hamilton principle and Galerkin method, the equations of nonlinear vibration of SMA damper-cable system have been set up.

根据Hamilton原理，结合Galerkin法，建立了SMA阻尼器—拉索系统的非线性振动方程。

Iteration and scheduling for coupling tasks set in concurrent product development process is analyzed, and Gaussian elimination combined with Genetic Algorithms is used to realize intelligentized method of it.

对产品开发耦合任务组迭代和顺序规划进行了研究，把遗传算法基本原理与高斯消去算法相结合，实现了耦合任务组顺序规划的智能化。

In this paper,a new method in which the principle of the contact trace is combined with auto programming in grinding a finger gear cutter is introduced.

本文介绍了采用接触轨迹原理结合自动编程刃磨指状齿轮铣刀的新方法。

It is put forward to fast discriminate and calculate the design feasibility of external gear shaper cutter s according to the limited area of displacement coefficient and with AutoCAD software.

提出利用变位系数选择的限制区域并结合AutoCAD设计软件实现对外插齿刀设计可行性的快速判别与计算，介绍了基本原理、插齿刀变位系数限制区域的确定和插齿刀设计可行性的判别方法。

Automatic Programming for NC Machining of Gear Indexing Cam with Smaller Cutter;2. Study on the Technologies of Computer-aided Designing and Programming of Gear Indexing Cam

本文结合弧面分度凸轮加工的工程实际，以微分几何和空间曲面啮合理论为工具，对弧面分度凸轮机构的传动规律、啮合原理和数控加工进行了系统的研究。

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。