查询词典 numerical system

Therefore, the constitution of an accurate numerical analysis system for the transonic axial compressor becomes more and more prevalent.

因此，建立一套能够准确分析跨声速轴流压气机流场的分析系统是当前许多叶轮机研究者竭力追求的目标。

of programming design and manual operation trapeziform figure in system of numerical control lathe Corresponding project to problems is provided synchronously.

可编程控制器在机械制造的设备控制中应用非常广泛，通常用来实现逻辑控制和顺序控制，在普通车床数字化改造中，用PLC作数控系统的核心部件是一个新的课题。

Based on the field investigations of Indiacharcial trema root morphology, one can establish a 2-D numerical model of soil/root system to simulate the pull-out test at field site.

依据山黄麻现地调查之根系形态，吾人可建构含根土之二维数值模型并进行现地根系拉拔抗力试验之数值模拟。

Its dominant merit is that it overcomes the deficiency of existing methods based on numerical calculation and can realize significant or even absolute decoupling decoupling between the nominal responses of system outputs. Moreover, the adjustable parameters of the decoupling controller matrix can be tuned on-line in a monotonous manner to cope with the unmodelled process dynamics.

其突出优点是克服现有的数值化求解方法的局限，能够实现标称系统输出响应之间的显著乃至完全解耦，并且能够在线以单调方式整定解耦控制器矩阵的可调参数来适应被控过程的未建模动态。

With the support of a major research grant of Zhejiang Province (No. 001101027) and the Plan of Promoting Education of Excellence of Zhejiang University in the 21st Century, this dissertation is devoted to address the above problems and fabricate an L-band EDFA with low cost, high performance and technological innovation.First the mechanism of an erbium doped fiber amplifier is introduced. Various theoretical models based on classical rate propagation equations are summarized and compared for their applications. We use a modified numerical model based on the Giles model, which agrees with the experimental results well. This serves as the theoretical base for the whole thesis and will be used to optimize the characteristics of EDFAs. A novel method based on a map of noise figure and gain is proposed to analyze efficiently the dependence of the noise figure and gain for EDFAs on the EDF length and the pump power. The characteristics of various EDFAs are studied and compared.Secondly, some important parameters are introduced to describe the characteristics of EDFAs. The methods and the experimental setups for measuring the gain and noise figure of an EDFA are emphasized. We introduce how to measure the characteristics of each component of an EDFA, especially the gain and absorption coefficient of an erbium doped fiber.Thirdly, four types of simple and novel L-band EDFA structures with low noise, high gain and low gain ripple are proposed to satisfy the requirement of a DWDM system. They can be classified into two categories. In the first category, a single ASE pumping is served asa secondary pump. This category includes the following three types. Type: a new construction using a fiber Bragg grating in an unpumped EDF section at the input side. Type: a new structure of L-Band EDFA with two-stage pumps, which utilizes the forward ASE as a second pump.

本论文本着科技创新、服务于生产实践的精神，以设计价格低廉，性能优越、结构合理简单的L-band EDFA为目标，依托浙江省科技厅重大科学基金资助项目(001101027)和浙江大学振兴教育计划资助的全光网络的搭建—《光通信技术》课程实验建设项目，展开了如下工作：首先，介绍了掺铒光纤放大器的工作原理，归纳总结了基于速率方程基础的EDFA的各种理论模型，分析比较了各个模型的特点和适用场合，最终选择完善的Giles理论模型作为本论文分析设计EDFA的理论基础；针对实际实验条件提出了修正的EDFA模型的数值计算方法；创新地提出了增益—噪声系数全局分析法，直观有效地分析了EDFA的增益和噪声系数与掺铒光纤长度和泵浦功率的依赖关系，并对各种EDFA的性能作了全面的比较；第二，介绍了掺铒光纤放大器特性参数的定义与测量方法，重点介绍了噪声系数和增益系数的测量方法及实验装置；介绍了组成掺铒光纤放大器各组件的特性测量方法，重点介绍了测量掺铒光纤参数的方法和实验装置；第三，针对WDM系统对L-band EDFA谱平坦、低噪声、高增益的要求，我们创新地提出了四种不同的L-band EDFA结构，按设计思路可以分为两大类：一类是基于单抽运二级泵浦法，这一类包括在未泵浦掺铒光纤的输入端插入一根布拉格光纤光栅的两段L-band的EDFA的新结构；基于前向ASE光作为二级泵浦源推动下一级EDF工作的泵浦分配、两段级联L-band的EDFA的新结构；基于单根光纤光栅、泵浦分配、两段级联的EDFA；另一类则是基于同时应用前后向C-band ASE作二级泵浦源的双抽运法，如基于前后向ASE光作为二级泵浦源的三段级联L-band的EDFA的新结构。

The two-dimensional flow field calculation software is developed by simple numerical method for determining the velocity distribution in the modul of MPC system.

本研究中，应用Simple数值计算方法开发了求解MPC系统模块结构中二维流场分布的计算软件。

At the same time, variational equations, their finite element formulations and numerical convolved integration algorithm of the model in current configuration usually called co-moving coordinate system are given.

基于非线性几何场论，建立了材料非局部连续模型、变分方程及相应的实时拖带系大变形有限元数值模型，设计了这一模型的数值卷积算法。

We can see from the numerical results of the improved exhaust system in acoustic and fluid fields that: the improved design succeeds in increasing the attenuation performance and reducing the pressure loss and meliorating the aerodynamic quality.

改进后的流场和声场分析结果表明：改进设计使得排气系统的空气动力特性、低频、高频消声特性等方面都较原结构有所改善，达到了预期改进目标。

Numerical forecasts call for very diverse scenarios after t+48, with some recurving the system to the north/northeast while both ECMWF and NGP predict that PARMA will enter the South China Sea via the northern tip of Luzon. After t+96, PARMA's track might be influenced by the interaction between typhoon MELOR and itself.

各数值模式对芭玛於 t+48 后的路径出现重大分歧：部分模式指芭玛将逐渐转向偏北/东北，而 ECMWF 跟 NGP 模式均指芭玛可能透过吕宋北部进入南海。96 小时后，由於台风茉莉逐渐靠近，它们间的相互影响可能令芭玛的路径出现变化。

Through theoretic reckoning and simulating analyzing, several control strategies for shunt APF were compared and chose ip-iq arithmetic ofthe instantaneous reactive power theory control strategy as the right scheme to produce the instructing current. Based on it, some new control arithmetic was subjoined to suppress the resonance in system and balance the dc side capacitor voltage. Two topologies of main circuit were compared and chose the three-phase voltage-source converter with a split-capacitor as its main circuit structure. The numerical scales of the dc side capacitor and inductance of reactors were calculated. The high-pass filters were designed to eliminate effectively the highfrequency harmonics produced by APF.

通过理论计算和仿真分析，比较了并联型APF的几种控制策略的优点和缺点，从中选择瞬时无功理论控制策略i_p-i_q计算方式为指令电流产生的算法，并在此基础上增加了抑制系统谐振和平衡直流侧电容电压的控制；比较了并联型APF主电路的两种常见形式，从中选择了三相电压型变流器的主电路形式；算出适合该APF的直流侧电容和出线电感的参数；设计出能有效消除APF产生的高次谐波的高通滤波器。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐