查询词典 numerical signal

But in the numerical calculation process, such as numerical differentiation, if we use these numerical methods inadequately, then it may be induced non necessary numerical error, including round off and truncation error.

因而常必须以值方法替代解析解，但是在值计算的过程中，很容引入额外的计算误差，包括舍位误差与截断误差。

In chapter5, the serial properties of numerical range of operator polynomial are put firstly. Secondly, the relation between numerical range of operator polynomial and n-numerical range are considered. Thirdly, in the light of matrix norm, matrix singular value, the regions and bounds of numerical range and spectrum of operator polynomial are dicussed carefully.

第五章研究了算子多项式数值域的性质、算子多项式数值域与n-次数值域的关系，特别地利用矩阵范数、矩阵的奇异值、非负矩阵的理论、友矩阵为工具，给出了算子多项式数值域及谱的范围全面刻画，并深刻地研究了算子线性束的正则性的等价条件及谱分布。

The objective of this study is aimed at the implementation of parallelized numerical quadrature routines. The algorithm we choose for numerical quadrature routines is the so called "Adaptive Romberg Tree integration scheme"(abbr."ARTint") proposed by Lin et. al.[1997]. This numerical quadrature scheme can arrange the function evaluation points adaptively in accordance with characteristic of the trend of variation in integrand function values. When the accuracy of the numerical quadrature value is requested to be increased, a newer and larger set of function evaluation points must be incurred. The main advantage of ARTint method is the inclusion of all function evaluation points used in previous stages. It is this feature of ARTint method that makes it a quadratue scheme with prominent computation efficiency.

本研究在探讨数值积分程式之平行化，所使用的演算法为林聪悟与林佳慧[1997]一书所提出的「Romberg树自动布点数值积分」架构，此一数值积分方法能以适应被积函数值变化情形方式自动安排积分点来进行数值求积计算，在提高阶数以获得更高精度积分值的过程中，此一方法只须再计算新增加积分点的函数值，搭配先前已计算过的函数值的重覆运用即可获得更精确的数值积分估计值，如此将能减少升阶过程中函数求值计算的次数，有效率地完成单重积分的数值计算。

In this thesis, I summarize the theoretical calculation method, applied scope and notice of siphonic drainage system, and point out the advantage of siphonic drainage system compared with gravitation drainage system. In the archetype experiment study of siphonic drainage tube, I adopt different tube diameter and different structural height to survey the drainage volume and press in different place. I observe various kinds of flow state, and get chief factors which influence hydraulic peculiarity of system as the tube diameter or structural height, and find out the relevance of factor to flux. I apply CFD Fluent software and adopt standard k-ε model and RNG k-ε model, then use finite volume method and second-order upwind scheme to discrete numerical model, while coupling numeration of velocity field and press is based on SIMPLE. In the numerical simulation of curved part of tube, siphonic drainage tube experiment system and multi-outlet siphonic drainage system, I make research on internal velocity and press of system in different project condition by changing the tube diameter of curved part, negative press value in tube export and improving the quantity of water gutter. This thesis first adopts a method of combining archetype experiment and numerical simulation to study the siphonic drainage system, test and verify the validity of experiment and numerical simulation, and makefurther study on system, it solves the problems of limited testing conditions, and has a logical results, it can provide a valid method for optimizing and designing the drainage tube-net system. The conclusion have referring value for study and design of siphonic drainage system.

本文首先对虹吸式排水系统理论计算方法、适用范围以及注意事项做出总结，并分析了虹吸式排水系统的优势；再对虹吸式排水管道进行原型试验研究，采用不同管径不同立管高度，对系统流量、管道压强进行量测，观察了各种工况下的流态，对其水力特性进行研究分析，找出影响水力特性的落差、管径主要因素以及与排水量的关系；进一步应用计算流体力学Fluent软件，采用标准κ-ε模型与RNGκ-ε模型，计算过程应用有限体积法和二阶迎风格式对数值模型进行离散，速度和压力的耦合采用SIMPLE算法，分别对系统弯管段、虹吸排水管道试验系统、多斗虹吸式排水系统进行数值模拟分析，通过改变管段弯头处半径、管段出口负压值、增加雨水斗数对不同工况下系统内部的速度和压力进行研究；本文首次采用结合原型试验与数值模拟相结合的方法，对虹吸式屋面雨水排水系统进行研究，试验与模拟相互验证，并进行拓展，很好地解决了虹吸式屋面雨水排水系统由于试验条件限制问题，结果正确合理，为排水管网系统设计和优化研究提供了有效的方法，对工程设计有较好的参考价值。

The company is in line with " the product has no limits, the principle that based on sincerity and pursue being outstanding ", invest the numerical control woodworking machinery trade meticulously, besides researching and developing the products that numerical control woodwork engraves the milling machine , numerical control and carves the milling machine , three major series and a dozen specifications of numerical control carving machine, having developed 10 axle cantilever woodwork machining centers again recently, the real wooden door, special-purpose bull of wave board engraved the milling machine , changed a one hundred sheets of woodwork and engraved the milling machine automatically, multicipital workingbench movement woodwork engraves professional equipment , such as milling machine ,etc..

公司本着&品无止境，诚信为本，追求卓越&的原则，精心投入数控木工机械行业，除研发出数控木工镂铣机、数控雕铣机、数控雕刻机三大系列十几个规格的产品外，近期又研制了10轴悬臂木工加工中心，实木门、波浪板专用多头镂铣机、自动换刀木工镂铣机，多头工作台运动木工镂铣机等专业设备。

The numerical control technology is carries on the control with the numerical information to the mechanical movement and the work process the technology, the numerical control equipment is take the numerical control technology as representative's new technology the integration of machinery product which forms to the traditional manufacture industry and the emerging manufacturing industry seepage, namely so-called digitized equipment, its technical scope cover very many domains:(1) machine manufacture technology;(2) information processing, processing, transmission technology;(3) automatic control technology;(4) servo actuates the technology;(5) sensor technology;(6) software technology and so on.

数控技术是用数字信息对机械运动和工作过程进行控制的技术，数控装备是以数控技术为代表的新技术对传统制造产业和新兴制造业的渗透形成的机电一体化产品，即所谓的数字化装备，其技术范围覆盖很多领域：(1)机械制造技术；(2)信息处理、加工、传输技术；(3)自动控制技术；(4)伺服驱动技术；(5)传感器技术；(6)软件技术等。

In addition every industrially developed country in the world also classifies the technology and numerical control equipment of numerical control as the strategic materials of the country, not merely take the great measure to develop one's own numerical control technology and industry, and implement blockading and restrictive policy to our country in " high-grade , precision and advanced " key technology and equipment of numerical control.

此外世界上各工业发达国家还将数控技术及数控装备列为国家的战略物资，不仅采取重大措施来发展自己的数控技术及其产业，而且在&高精尖&数控关键技术和装备方面对我国实行封锁和限制政策。

Numerical control is transferred to the puncher of the tower (2, the intersection of processing and the intersection of board and pieces of the intersection of 1.25X3 and rice), the intersection of numerical control and the intersection of laser and cutting machine, the intersection of numerical control and plasma / the intersection of flame and cutting machine, numerical control roll over advanced apparatuses such as the curved machine (100TX3.2 rice),etc., there is ordinary puncher of large tonnage, while being ordinary, have spraying and electroplate craft at the same time, possess panel beating, machine add, weld and surface deal with, assemble the one-stop service, can meet to process demand is one comprehensive relatively better processing forming a complete set enterprise multi-level customer in an all-round way.

既有数控转塔冲床（2台，加工板幅1.25X3米）、数控激光切割机、数控等离子/火焰切割机、数控折弯机（100TX3.2米）等先进设备，又有大吨位普通冲床、普通折弯机和车、铣、刨、磨、线切割、弯管、卷圆、等离子切割等机械设备以及二保、氩弧、网焊等各类焊接设备，同时拥有喷涂和电镀工艺，具备钣金、机加、焊接、表面处理、装配一站式服务，能全面满足多层次客户的加工需求，是一家综合性较强的加工配套型企业。

Numerical simulations by assemblies of circular panicles can qualitatively reflect the general characteristics of liquefaction behavior of sand. The interval effect of aspect ratio of elliptical panicle on the mechanical behavior of numerical sample is obtained, and the reason is related to the initial average co-ordination number. The regularity of evolution of fabric in the process of sand liquefaction under cyclic loading can be qualitatively achieved by using the numerical sample randomly mixed of panicles with different shapes. Numerical simulations can not only demonstrate the macro phenomenon of particle breakage, mostly importantly, it can also expose the evolution of particle breakage microscopically, and would contribute to further research of the micromechanics of particle breakage.

研究结果表明：Hertz-Mindlin非线性接触模型适用于变围压条件下砂土力学性质模拟；纯圆颗粒模拟能够定性地反映饱和砂土振动液化的一般规律；颗粒长短比变化对砂土力学性质的影响具有区间效应，其原因与粒间初始平均接触数有关；不同形状随机混合试样能够从定性规律上反映振动液化过程中砂土的细观组构演化规律；数值模拟不仅可得到颗粒破碎宏观响应，而且可以分析内部接触力变化和实现对粘结破裂位置的追踪，从而可进一步研究颗粒破碎细观力学机制。

The possiblehost objective reason all is very many, but, our country numericalcontrol engine bed function part development backwardness -- varietyfew, unit technical level low, performance quality insufficientlystable, the cost stays at a high level, the delivery insufficientlywas prompt and so on -- not to be able to satisfy the numericalcontrol engine bed main engine product need to develop, had noalternative but to say was most direct, the most main reason, Becauseall numerical controls engine bed all is by each kind of function part(including host 轴头, straight line rolls guide rail, ball bearingguide screw vice-, numerical control tool rest, knife storehousemanipulator, rotary table, numerical control servosystem, surveyfeedback as well as safe protective equipment and so on), the functionpart which on foundation rack and so on the lathe bed, column thecollection attire becomes is the numerical control engine bedimportant component, moreover is the indispensable part.

可能主客观原因都是很多的，但是，我国数控机床功能部件的发展落后──品种少，单元技术水平低，性能质量不够稳定，成本居高不下，交货不够及时等──满足不了数控机床主机产品发展的需要，不能不说是最直接、最主要的原因，因为所有的数控机床都是由各种功能部件（包括主轴头、直线滚动导轨、滚珠丝杠副、数控刀架、刀库机械手、回转工作台、数控伺服系统、测量反馈以及安全防护装置等）在床身、立柱等基础机架上集装而成的，功能部件是数控机床的重要组成部份，而且是不可或缺的部份。

In the days of sailing vessels the crew were afraid they would be becalmed on the ocean.

在使用帆船的时代，船员们担心他们会因为无风而无法在海洋上航行。

As long as foreign donors pay the PA's salary bill, few expect a new intifada.

只要外国继续为巴权力机构的薪水买单，希望发动新暴动的人便寥寥无几。