交流分析

Analyzing every kinds of variable speed method and getting the conclusion that VVVF is the best method of all alternating variable speed.

分析了各种交流调速方法，得出变频调速是目前最理想的交流调速方法的结论。

In this paper, to development tendency of electrical source of alternating stable voltage, working principle of switch mutual complementary alternating regulator are proposed and analyzed .

本文针对国内交流稳压电源的发展趋势，提出并分析了开关互补式交流稳压器的工作原理。

The high-voltage high-power multilevel converter and AC motors drive techniques are summarized compendiously for domestic and overseas studies in the prolegomenon of this dissertation. The evolution and research status of multilevel converter topologies are analyzed, the development of AC variable speed techniques and the characteristic of DTC are discussed, also, the aim and significance for the research are demonstrated. In this dissertation, SVPWM pattern and implement method have been addressed comprehensively for three-level NPC inverter.

本文绪论部分针对国内外高压大容量多电平变换技术和交流传动控制技术作了简要综述，着重分析了多电平拓扑结构的发展和研究现状，讨论了交流调速的发展和直接转矩控制技术的特点，指出本文选题的目的和意义。

My text manage methods of film theoretics and culture study. By the way of analysing Ang Lee's experience and forming process of his cultural identity, I mean to point out the necessary and necessity of communion and introjection between different cultures in the direction of globalization, at the same time, discuss his status and effect in eliminating culture bulwark and promoting Chinese-occident cultural communion.

本文运用电影理论、文化研究等方法，通过分析李安的成长经历和文化身份的建构过程，意在指出全球化趋势下不同文化之间交流与融合的必要性和必然性，同时探讨他在消除文化壁垒、促进中西文化交流方面的地位和作用。

This dissertation extracts ten key elements of RIN that influence the leading technique ability of regional industry creation, from the aspects of technique terrace, creative funds, industry multitudinousness and creative culture.

本文从RIN创新主体间资金流的强度和协调性两个维度，设计了刻画RIN内交流强度和交流结构特征的指标体系，可以作为对RIN进行横向或纵向比较分析的一个技术平台。

On the one hand the Orientalist consciously or unconsciously attempts to control and manipulate the process of dialogue and communication, on the other hand they are frustrated again and again because they meet the elastic resistance of the sophisticated and wise India civilization. As a result, the contact and the communication between the West and the East were spoiled, suspended and even aborted, making both sides frustrated and upset.

通过条分缕析的文本分析，暴露在这个过程中作为政治霸权与文化霸权的殖民者，一方面对双方之间的对话与交流进行有意无意的策划、操纵；一方面他们的操纵过程又因为受到古老印度文明的"软性"抵抗而不断受到挫折，因此使这些接触、交流和试图进行的所谓"东方"与"西方"的"联结"或被"悬置"或被破坏，其结果只能以不愉快甚至于导致冲突而告终。

The dual DSP controllers were used to realize all the control functions for the positioning control of a squirrel-cage induction motor for high-performance motion control applications.

从探讨交流感应马达动态模型的推导，PC-SIMULINK为基础的交流感应马达模拟方块建立，参数的量测与验证，电流控制策略的决定，伺服控制架构的分析与设计，在本论文均有完整的讨论与说明。

Based on the rigorous analysis of the kinetic process of both primary and secondary electrons, the related surface charges were analyzed, and the energy gain of emitted electrons was proportional to the square of the ratio between the tangential and normal component of electric field. In this process, the image force of mirror charges would result in an energy loss. Meanwhile, the effect of field alternation of power frequency ac voltage on electron movement could be ignored.

在前人工作的基础上，进一步严格推导了场致一次发射电子和二次电子的运动方程，分析了电子发射引起的绝缘材料表面带电，表明电子发射后的能量增益正比于场强的切向与法向分量比值 F /// F ^的二次方；同时考虑了在电子发射和运动过程中电荷镜像力的作用，并探讨了交流电压下表面带电的情形，认为当考虑电荷镜像力的作用时，电子的能量增益可能变小，而工频交流电压下电场交变对电子运动的影响可以忽略。

The research work of this paper is divided into five parts: The first ,according to the work characteristics of ship's auxiliary boiler, this paper is to design applied project in the automatic control system of ship's auxiliary boiler; The second, according to the work request of the cargo winch of alternating three-speed change-pole speed-adjusting, this paper is to determine adopting the method of the PLC control; The third, this paper is to design PLC application in three -phase induction motor control, to give the ladder chart, program and input and output circuit diagram; The fourth, this paper is to research the method of the ship's combined starting screen automatic control with the PLC; The fifth, this paper is to inquire the possibility of apply the PLC in ship's engine room surveillance system; According to the comprehensive analysis of above actual example of ship's auxiliary machinery automatic system with the technique of PLC; not only can use the technique of PLC to replace traditional relay-contactor control technique in ship's auxiliary machinery automatic system, but also can get the conclusion of the former is more dependable and more clever than the latter, the maintenance is more convenient, thus develop a new path for ship automation.

本文研究的工作主要包括五个部分：第一，根据船舶辅锅炉的工作特点，设计PLC在船舶辅锅炉自动控制系统中的应用方案，主要有PLC选型及输入输出点的设计，画出系统控制梯形图并分析工作原理；第二，根据交流三速变极调速起货机的工作要求，确定采用PLC控制的方法，进行控制系统的硬件设计和软件设计，并分析工作原理：第三，设计了PLC在三相异步电动机控制中的应用，给出了控制梯形图、程序及输入、输出接线图；第四，研究了用PLC实现船舶组合起动屏自动控制的方法，进行了系统的电源设计和软件设计，给出系统工作流程图；第五，探讨了船舶机舱监视系统应用PLC的可行性，将继电器报警线路改为用PLC控制报警，给出系统硬件图和软件梯形图，并分析了PLC机的选型、抗干扰和应用PLC的经济效益和社会效益等问题。综合以上船舶辅助机械自动控制系统采用PLC技术的实例分析，可以得出船舶辅助机械自动控制系统不但可以使用PLC技术取代传统的继电器接触器控制技术，而且前者比后者更可靠、更小巧，维护保养更方便的结论，从而为船舶自动化开辟了一条新的路径。无忧毕业设计网 www.5ubs.cn

At first, this paper gives the brief introduction of the history and present status of accelerometer and its testing technology, the working principium and math model of the liquid floated pendu-lous accelerometer, and then, decides the binary width pulse force retrim loop as the design proposal of testing system, researches the transfer function of every part in the system emphasizly, analyses the stability of the whole accelerometer testing system from the angle of control theoretics by the open loop transfer function of system, and designed the correcting net, analyses the basal problems such as resolution, sampling restraint, precision and so on, designs the hardware testing circuits such as preamplification, band-pass filter, alternating amplifier, phase sensitive demodulatorn, pulse-width modulation, frequency scale circuit, moment current generator. Finally, using the graphics program language LabV-IEW which is designed for testing field especially by NI accomplishes the solfware design of testing system,realized the testing functions.

首先对加速度计及其测试技术的发展历史和现状，液浮摆式加速度计的工作原理和数学模型等作了简要的介绍，然后确定了以二元调宽脉冲再平衡测试回路为设计方案，并从控制理论的角度进行了分析，着重研究了系统中各部分的传递函数，利用系统开环传递函数分析了系统的稳定性，同时设计了系统的校正网络；分析了二元调宽脉冲再平衡测试回路的分辨率、采样约束以及测试精度等基本问题，并按照系统分析的结果设计了包括前置放大、带通滤波、交流放大、相敏解调、脉宽调制、频标电路以及力矩电流发生器等测试系统各部分硬件电路，验证了电路的正确性，最后按照测试系统的要求，采用了美国NI公司专为测试领域所开发的虚拟仪器工具——LabVIEW作为测试软件开发工具，利用该图形化编程语言完成了测试系统软件部分的设计，实现了测试功能。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。