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This paper introduces the basic theory of fly-back topography and current mode PWM firstly. Then the total structure of the single-chip controller is present according to the function requirement and the working theory and the working principle are showed based on its actual application.

文中首先分析了反激变换的拓扑结构及电流反馈模式PWM控制的工作原理，然后根据设计要求完成了AC/DC电源管理集成电路整体结构的设计，同时结合实际应用电路阐述了其工作原理。

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。

According to the three types of design patterns,the use of State,Flyweight and Singleton patterns in a robot control system are explained,and it is proved that design patterns can make system more extensible and more maintainable,and make requirement changes be easily handled.

针对设计模式的三种类型，详细介绍了 State 模式、Flyweight 模式和 Singleton 模式在机器人控制系统的应用，说明了设计模式可以使系统具有可扩展性和可维护性，使系统可以更加从容地面对需求变更。

The only requirement is including the following footer with it...

唯一的要求包括以下步行者以它。。。

Life science is the theme of 21th century. The development of it is the requirement of period progress. Aid reproduction technique; Organ transplantation; Gene engineering;Clon stem cell technique. All above forebode that human are getting into the life territory which is the core territory of themselves.

21世纪是生命科学的世纪，生命科学技术的发展是时代发展的必然要求，从辅助生殖技术到器官移植，从基因工程到克隆、干细胞技术，人类正在向自己最核心的生命领域挺进。

Presently, there are many methods and instruments applied for measuring forestland area. The current laws and regulations is no uniform requirement.

目前林地面积测量的方法和仪器较多，相关法律法规对测算的方法也没有统一规定。

The result shows that the fabric levelnessis raised by 1.7 grade,which reaches to the crease resistance requirement for high grade shirts,which includes the levelness≥3.5 grades,the tearing strength≥681CN,and the formol left in fabric≤75mg/kg.

由于不同的树脂整理剂会产生不同的效果，因此选择适宜树脂整理剂及其添加剂助剂等，优化工艺条件，是提高棉织物抗皱整理效果的关键。本文通过选用合

Academic innovation is the essential requirement of the Marxism, it is the fountainhead of Marxism vitality.

理论创新是马克思主义的本质要求，是马克思主义生命力的源泉。

However there are some differences in the learning motivation in terms of different backgrounds:① The higher the academic degree holders, the lower the intensity of the learning motivation in self-development, social contact, family requirement and degree pursuing.② The students from town and villages show great motivation in Better Serving Society, however the students from cities pay more attention to the assessments from family and working company.③The intensity of the motivations in female students in pursuing knowledge, self-development and social contact are apparently stronger than male students.④With the increasing of age, the motivation intensity decreases in the aspects of self-development, career-development and competition or promotion. The students in the age of 40"s to 50"s pay more interests in educating children.⑤The motivation intensity in Better Serving Society, Avoid Failure in The Work and Better Educating Children decreases with the increasing of the income. Middle income class emphases more in promotion.⑥ The intensity of motivation in pursuing knowledge is very strong in state-worker and free-lancer. Teachers pay more attention to career development and the free-lancer emphasis in developing enterprises and self-expressing.

在对比分析中，成人学员因学历、来源地、性别、年龄、收入、职业的不同，其学习动机存在一定的差异：①随着学历层次的升高，成人学员在发展、交往、家庭、文凭动机的多个子项上表现出差异，动机强度依次降低；②县乡学员在"更好地服务社会"项目中比城市学员表现强烈，而城市学员更重视家庭及单位对自己的看法与评价；③女性学员在求知、职业、交往三大类上的动机水平较明显高于男性学员；④在发展、职业、竞争或提升三个方面，随着年龄的增加，其动机强度呈递减趋势，而41－50岁的学员在"为了更好地教育子女"这一项上表现尤为突出；⑤在"更好的服务社会"、"避免工作失败"、"更好的教育子女"三个项目中，随着收入的增加，其强度水平依次减弱，中间收入的学员较其它两层次更在意"得到提升"；⑥不同职业的学员有不同的动机表现，公务员与自由职业者的求知动机表现强烈，教师的职业动机水平相对偏高，自由职业者强调"发展事业"与"表现自己"。

In order to solve this problem, a peach breeding work was conducted by Taiwan Agricultural Research Institute. Peach breeding goals is to develop low chilling requirement, low acidity, short fruit development period, large, attractive, good quality, white- fleshed, melting freestone peach and nectarine cultivars.

为解决这些问题，台湾省农业试验所近年积极从事平地水蜜桃的育种工作，其育种目标为成低需冷量、低酸、果实生育日数短、大果、外观鲜艳动人、品种好、果肉白色、溶质、离核的毛桃与油桃新品种。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。