专业英语大作业

专业英语大作业篇一

专业英语 大作业

专业英语大作业

Mobile communicationsapplications

were reviewed

Abstract:Along with the rapid development of mobile communication market, users of higher performance of mobile communication system is put forward higher request,

hope to enjoy a richer and high-speed communication service. The second generation

of mobile communication operators development speed are easing and increasingly

fierce competition, to find new sources of growth, through the development of data

services to improve their service quality and business types, need the support of 3 g.

At the same time as the second generation of mobile communications radio frequency

resources become increasingly nervous, can not meet the communication needs long-term development needs.

Keyword:mobilecommunication system,communication service,The 3rd Generation

Telecommunication

1：A brief introduction, mobile communications

Mobile communication, Mobile communication) is a communication between the

Mobile body, or communication between Mobile and fixed bodies. Moving a body

can be a person, such as cars, trains, ships, the radio in the moving state of the object.

Mobile communication system consists of two parts:

(1) space system; satellite

(2) the ground system: (1) mobile radio and antenna; (2) terminal station, base station. Mobile communication system since the 1980 s was born in 2020 will generally after

five generations of development, and by 2010, from the third generation of transition

to the fourth generation (4 g). To 4 g, in addition to the cellular telephone systems,

broadband wireless access systems, millimeter-wave LAN, intelligent transport

system (ITS) and stratospheric platform (HAPS) system will be put into use. The

trend of future generations of mobile communication system is the most obvious is to

require high data rate, high mobility and seamless roaming. To achieve these

requirements in technology will face a bigger challenge. In addition, the performance

of the system (such as cell size and transmission rate) largely depends on the high and low frequency. Given these technical problems, some system will focus on providing

high data rate, some systems will focus on enhanced mobility or expanding coverage.

From a user's point of view, you can use the access technology including: cellular

mobile wireless systems, such as 3 g; Wireless systems, such as the DECT; Close

communication system, such as bluetooth and DECT data system; Wireless local area

network (WLAN) systems; Fixed wireless access or wireless local loop system;

Satellite system; Broadcasting system, such as the DAB and DVB - T; ADSL or Cable

Modem.

2.the history of mobile communication and the characteristics of each

generation of mobile communication{专业英语大作业}.

The first generation (1 g) analog cellular network are the main features, is in the late

1970 s and early '80 s began to lead. One of the most representative is the AMPS of

North America (Advanced Mobile Phone System), European TACS (Total Access

Communication System) System, and in addition, a Nordic NMT and Japan HCMTS

System, etc. The second generation (2 g) digital as the main characteristics of a digital cellular

mobile communication system, and it officially to the commercial in the early 1990 s.

One of the most representative of European time division multiple access (TDMA),

GSM (GSM for Group Special Mobile, after 1989 changed to Global System for

Mobile Communication), North America, code division multiple access (CDMA) IS -

95 System, and another Japanese PDC System, etc.

3.the characteristics of mobile communication

(1) mobile communications using radio waves to transmit information. Between the

mobile communication base stations to the user must send messages by radio waves.

Wireless transmission environment is very complex, however, lead to the radio waves

propagation characteristics in general is very poor, in addition, the movement of the

mobile station will also bring the doppler effect, make the receiver signal voltage

amplitude, phase changing with time and place, seriously affecting the quality of the

communication. This requires that in the design of mobile communication system,

antifading measures must be taken to ensure the quality of communication;

(2) mobile communication work under strong interference environment, including the

main interference intermodulation interference, adjacent-channel interference and

same frequency interference, etc.;

(3) the limited capacity of communication. Frequency as a kind of resources must be

reasonable arrangement and distribution, in order to meet user demand increase, only{专业英语大作业}.

in a limited existing spectrum take effective measures, the use of frequency channel such as narrow band, repeated use, such as narrow frequency band interval method to

solve;

(4) communication system is complicated. Due to the mobile station movement at any

time, in the area of the communications needs to randomly choose wireless channel,

frequency and power control, address registration and handoff, roaming access

tracking technology, etc. That makes the signal type is more complicated than the

fixed network. On the net and billing methods also have special requirements, so the

mobile communication system is more complex;

(5) high demand for mobile station. Mobile station is not a fixed position for a long

time, it is difficult to predict the influence of the outside world, this requires a mobile

station has a strong ability to adapt. In addition, it also requires stable and reliable

performance, easy to carry, small size, low power consumption and high power, low

temperature, etc. At the same time, as far as possible the user easy to operate, adapt to

the development of new business, new technologies, in order to meet the use of

different people. This brings to the mobile station design and manufacturing.

4.the classification of mobile communication There are many types of mobile communication. According to different use

requirement and the workplace can be divided into the following kinds.

(1)the cluster of mobile communication Clusters of mobile communication, also called regional system of mobile

communication. Its characteristic is only a base station, antenna height for dozens of

meters to hundreds meters, covering radius of 30 kilometers, the transmitter can be up

to 200 watts. About dozens to hundreds of users, can be a vehicle, but also to

handheld. They can communicate with the base station, but also through the base station and mobile station and other local user communication, base station connected

to the city station networks.

(2)cellular mobile communication

Cellular mobile communication, also called village system of mobile communication.

Its characteristic is the whole a wide range of services division into many neighborhood, every community set up a base station, responsible for the contact area

of each mobile station and the control, the base station through the mobile switching

center contact each other, and connected to the central office. Advantage of the

characteristics of ultrashort wave radio waves propagation distance limited, leaving a

certain distance of the village can be repeated use frequency, the frequency can make

full use of resources. Each community of users in more than 1000, all the coverage

area of the ultimate capacity of up to 1 million users.

(3) satellite mobile communication

Mobile satellite communication. Forward using satellite signal which can realize

mobile communication, also can be used for vehicle-mounted mobile fixed satellite,

the equator for handheld terminals, with low and middle orbit satellite constellation of

satellites is more favorable.

(4)cordless phone

Cordless phones. For indoor and outdoor slow mobile handset communications,, the

use of the small power, communication distance nearly, portable cordless telephone.

They can be through the communication with local users for one-way or both sides to

communicate. Using simulation identification signal of mobile communication, known as the analog

mobile communication. In order to solve the capacity increase and improve the

quality of communication and increase the service function, now mostly use digital

identification signal, the digital mobile communication. On system has time division

multiple access (TDMA) and code division multiple access (CDMA) two kinds. The

former worldwide, in Europe the GSM (global system for mobile communications)

system, the dual mode pattern of North America standard IS a 54 and Japanese{专业英语大作业}.

standard of JDC. For code division multiple access, has developed Qualcomnn

companies in the United States IS - 95 standard system. The general trend of digital

mobile communication will replace analog mobile communication. And the mobile

communication will to personal communication development. In the 21st century has

become an important part of global information highway. There will be more brilliant{专业英语大作业}.

future mobile communication. Human beings in the 20th century is one of the greatest scientific and technological

achievements in cellular mobile communication, the rapid development of it is

extraordinary. The development of cellular mobile communication system has

experienced a from analog network to digital network, from the frequency division

multiple access (FDMA) to time division multiple access (TDMA) and code division

multiple access (CDMA) process. This progress is rapid. In the 21st century, people

continue to pay attention to the development of the second generation of cellular

mobile communication systems at the same time, has started the third generation{专业英语大作业}.

cellular mobile communication systems will be commercially available. At the same

time, many experts and scholars and mobile communications industry in active

research and development of the third generation mobile communication subsequent

new technologies and systems. Although 2.5 G system can easily transfer data,

however, due to the deficiency of it, that is not fundamentally solve the problem of the

wireless channel transmission rate is low, so it should be said that the 2.5 G is a

transitional product, and today people define of third generation (3 G) mobile

communication system can achieve the people basic demand for fast data

transmission business. References:

[1]Tang Xing. The history and development trend of mobile communication technology [J]. Journal of jiangxi communication science and technology, 2013 (2).

[2]Hu Kegang, shaun wang, Liu Lihong. Mobile communications in the wireless

location technology [J]. Journal of jilin university, 2015, 23 (4)

[3]The fourth generation mobile communication technology based on TDD [M].

Beijing: electronic industry press, 2015.7.

[4]chongyang. Digital mobile communication technology [M]. Xi 'an: jiangxi

university of science and technology press, 2016.5. Cao da zhong. Mobile

communication principle, system and technology [M]. Beijing: tsinghua university

press, 2014.2.

[5]Ajay R.Mishra, Beijing Posts and Telecommunications design institute, Institute of

communication. Wireless cellular network planning and optimization[M]. Beijing:

Mechanical Industry Press, 2014

[6] Chen Zhongmin, Tian Zengshan. On the software radio technology and its

application [J].in 4G Telecom. Express, 2016

[7]Du Dajun, sharp, Song Yang, Betty. A brief review and outlook of network control

system [J]. Journal of instruments and meters. 2013 (3)

[8]Rival, zhang ny, fu-chun sun. Network control system development present

situation and prospects of [J]. 2014(02) control theory and application.

[9]Zhang jie. Geographic space frame construction and application of digital city

专业英语大作业篇二

专业英语大作业

跨声速汽车高压比压气机涡轮增压器内燃机的研究和开发

郑鑫前，张杨俊，杨明阳

汽车安全和能源国家重点实验室，清华大学，北京100084，中国

2009年10月27日收到，2010年5月4日接收

引言：

涡轮增压器离心压缩机所需的压力比与内燃机功率密度增加。高压缩比造成叶轮跨声速流场中跨声速流稳定流量范围和deteriorates阶段效率的减小。在这种工作条件下，一个先进的高压比压气机设计完成。实验结果表明：涡轮增压器的最大压力比约为4.2，最大效率答80%以上，设计的转速率可达到稳定流量范围的34%左右。调查证明这种跨声速压气机涡轮增压器已经在一些汽车上应用，而且使功率提高了40%。

关键词：涡轮增压器、内燃发动机（IC）、压缩机、高压比、跨声速

1 介绍：

涡轮增压内燃机本身就是一件古老的引擎。大多数今天生产制造的所有型号、大小的柴油内燃机都使用涡轮增压而且自然吸气柴油发动机的生产比过去更容易。涡轮增压也越来越多的应用于汽油引擎。涡轮机是由压缩机和涡轮增压器组成的。压缩机是由涡轮机从废气中抽取能量带动的。与自然吸气发动机相比较，涡轮增压机的好处是功率增加，油耗减少和排放减少。

面对近些年来能源枯竭和日益严重的环境污染问题，在未来中，涡轮增压技术会变得越来越重要。高压缩比涡轮增压技术是实现柴油机的功率增大、减少排放、大大提高发动机经济性和减少二氧化碳排放目标必不可少的技术。特别是用高压缩比来弥补高废气循环率和气缸容积的减小而造成的功率和气缸工作容积损失，因此功率峰值就显得很特殊。另外，高增压比是高空作业必不可少的，尤其是对高空无人机引擎而言。

然而，高压比造成在压缩机中流速接近音速，造成复杂的流动现象，像使边界层震动交互影响，缩小压缩机的稳定流量范围，使车辆内燃机操作困难。拥有高压缩比的涡轮增压器已经在船舶发动机上发展起来。然而，压缩机在汽车上的稳定流量范围比在船舶上的宽一些。郑教授改进的压缩比为4.0：1的接近音速的离心压缩机是以压缩比为3.5：1的内燃机为基础的。尽管压缩比和压缩效率已经提高，但它的流速范围却并没有增宽。图1展示的是以报道的内燃机的性能为参考。拥有高压缩密度的现代汽车功率运行线在压气机特性曲线中没有表示出来。在高压缩比的压气机特性曲线当中运行线左边部分表示由于受到冲击稳定运行是不可能的。因此，由于达到最高水平的高压缩比压缩机的设计与发展加强后的特性曲线是主要的发行物。为了使压缩机达到这个要求，拥有较宽的流速范围的跨声速离心压缩机被设计和发展起来。

2完整的三维几何设计：

离心压缩机由三部分组成：叶轮，扩压器和蜗壳。首先，在NERC概念中仁宝模块，一个涡轮增压器专家设计了一个软件用来优化一维关键几何参数和性能预测。图2展示了优化参数之后的初特性满足设计要求。但是，通过取决于三位几何设计的以为仁宝模块无论最后的空气动力学性能能否达到性能预测的那样，特别是设计形状复杂的叶轮形状。

之后，Axcent®模块概念NREC®被用来设计叶轮的三维几何，它基于三部分：轮廓设计，桨叶角分布和叶片厚度分布。接下来，来解释基本原理和设计规则。

刀翼形状的轮廓对于压缩机的性能有很大的帮助。关于跨声速离心压缩机，进口叶尖

的相对马赫数对性能起了很重要的作用。确定进口叶尖半径的原则是通过是进口马赫数最小来减小激波强度，通过机翼前缘到叶轮喉部的流入量不能被计算的太多。诱导叶片应该是直的甚至是负弯曲的。对于这个设计，叶轮廓坡率从0%到20%而且在中间和结束部分的斜率增加。为了避免流动间隔，机翼前缘的曲线率和叶轮廓和中心轮廓的后缘应尽可能的小。对于跨声速流压缩机，它的叶轮廓前缘的曲线率通常为0为了避免或减小由激波造成的流量间隔。

根据欧拉方程，叶片角度决定了叶片加载，特别是在顶峰位置。叶片包角和叶片倾斜角度遵从桨叶角的分布。因为次音速压缩机的压缩比低，其最大载荷一般位于平均径向距离。对于跨声速压缩机，它的最大载荷位于其平均径向距离的60%到80%处，这意味着最大叶片角位于其70%到80%的位置。最大叶片角与叶片后缘角存在10º~20º的差值。 叶片应力和颤动对于发动机的可靠性是非常重要的，特别是对于跨声速压缩机而言。叶片厚度的分布规律可能会影响叶片的强度和对小气动性能的影响，特别是对亚音速压缩机而言。对于跨声速压缩机，其前缘的厚度应尽可能的薄为了减少诱导轮中的流动加速。中叶轮的振动频率和材料疲劳由锥速度分布决定决定，而锥速度又由叶片轮廓和轮毂的叶片厚度所决定。

根据上述跨声速压缩机设计的原则，Axcent单元被用来完成跨声速压缩机的几何设计。（图3以展示）主要的几何参数有：R1t/R2=0.73; R1h/R2=0.23;B2/R2=0.12; R5/R2=1.52 R1t是位于入口处叶轮的齿顶圆角半径；R1h是位于入口处叶片的中心半径；R2是出口处叶片的半径；B2是出口处叶片的宽度；R5是出口处扩压器的半径。叶片的倒角是38º然而,这种早期的一步是极大地影响后续数值的迭代,通过完全三维计算流体动力学在随后的数据模拟中取得成果。

为了进一步扩展跨声速离心压缩机的稳定流量范围，自行循环套管应用也被研究和采用。套管应用的结构参数在图4中展示。对个别参数的影响进行全面详细的分析之后，给出了这种叶轮机的优化几何参数：Sr=11 mm, br=5 mm, hb=13 mm, bb=8 mm,Sf=15 mm, hf=10 mm。在原因可以理解的范围中，参数变化分析的详细描述已忽略。

3 完整的三维CFD流分析

在前面的段落中，跨声速压缩机的设计原则已被讨论。压缩机的几何形状已被确定，自行再循环套管应用的结构也已被确定。压缩机的几何形状对性能的影响并不是孤立的而是彼此之间相互作用影响的。对于跨声速流压缩机，它的空气动力学性能比几何参数更敏感。因此，一维或三维的流速分析已成功的应用在亚音速压缩机上。完整的三维CFD分析工具应该用来分析流场和优化几何。事实上，上面所有的几何参数是根据以往的完整的三维流场数值模拟的优化设计的结果。尽管在演算的过程中花费的时间很多，全面分析仿真必须包括叶轮、扩压器、蜗壳和SCRT。

解算器适用于基于3 d稳定的可压缩流体流动有限体积格式使用CFD代码来解决Reynolds-averaged方程。中央计划被用于空间离散化当执行前面时间离散化的指令时。单方程一等式模型被应用于湍封闭。沿速度方向的总温度和总压力是进口边界条；静压力设置为出口边界条件。对于坚实的管壁无滑动和不渗透。叶轮和蜗壳之间的接口用冻结转子法来建模。角变化的流动数量超过了可以忽略的水平,是本研究工作的对象。因此，旋转系统相对坐标的计算，然而，本地传输流数量没有改变叶轮和蜗壳的相对位置。 在此次流动模拟测试中最重要的是网状SRCT的网格质量。一般来说，对于CFD解算器来说最重要的步骤是将单元尺寸归纳为数值问题。至于单元尺寸，SRCT和通道网通常差异显著；因此匹配这两个网格挑战性的问题。图5举例说明了拓补的叶尖间隙网格方法在这项工作中是有前途的。附加到通道上的间隙网状分为3级。第一级网格匹配

叶尖；第二级网格覆盖整个通道和比第一级小的通道；第三级分为3块，中间的一块匹配SRCT网格的单元尺寸。除了第三层次中期外所有叶尖间隙网格块都要旋转。冻结转子的方法是采用模型转子和定子块之间的接口，其他接口设置为完全匹配的边界条件。 在整个网格由9312021个单元组成。蜗壳的网格数量是414495,SRCT的数量是1528308，叶轮网由7369218个单元组成。整个网格和它的单一域如图6所示。数值模拟大约需要4 - 5天为高或设计质量流量计算，特别是在操作点附近需要7-8天。 因为压缩机失速或飙升是一种强烈的不稳定的过程，稳定仿真不适合预测起始点的精确失速。但因为CPU时间的要求，它常常被用来预测压缩机性能特性图。通常来说，稳定仿真不稳的位置被认为是失速点。在入口处由于不稳定的边界条件引起的再循环流的主要原因是数值停滞。结果，预测失速点应与进口网格域密切相关。这使得档位开始随便预测。然而，通过具有相同的入口域以及其他边界的不同类型的压缩机中稳定仿真来比较失速点是比较合理的。在目前的分析中通常被认为是失速点的条件解。

不能在这里讨论详细的优化过程，因为超出了本文的范围。只是最后，在图7中给出了压缩机的流场结构优化图。在这种流场流动分离的情况下速度向量显示没有重新标示。CFD的性能结果如图8所示。

完成气动设计后，通过ＡＮＳＹＳ对叶轮应力进行分析。考虑到模型的循环对称属性，对一个扇区作为目标进行计算。它分为25376个单位和42222个节点；中央节点的单元类型solid95单元,这是常用的有限元分析软件。

图9显示的是等效应力分布图。最大等效压力约为354MPa，它位于中心的后方磁盘。叶轮原料是锻铝合金,其屈服应力是375 MPa和压力限制是410 MPa。因此，它满足压力要求。

4 试验研究

随后，完成压缩机气动设计后，接下来的步骤是工程设计，测试部分压力，原型制造和验证测试。涡轮增压器的照片在图10中。

图11是一张自动涡轮增压器试验台包括控制单元，燃烧室的燃料供应,手动测试备份系统和其他子系统的照片。这个试验台能进行各种范围与介质流动各种压力比的稳定性能测试。用来探测的热电偶其测量温度公差能达到±1%；电子扫描压力胶囊被用来测量施加的压力(±0.2%)。涡街流量计测量体积流量(±1.0%)下游的压缩机,和非接触式转速测量的电磁传感器(±0.5%)。

实验结果如图12所示。与离心式压缩机设计、稳定的流量范围和效率目标相匹配。判断压缩机组操作的灵活性，一个无量纲参数被定义为：(mchoke-msurge)/mchoke。由于旋转速度的设计，这种稳定的流量范围提高了13%从21%到34%。此外,在当前情况下压缩机的最大效率仍超过80%。因此,该设计提供了一个非常好的平衡效率和良好的操作范围宽度。

图12显示引擎操作特点。最初的涡轮增压器，位于左侧的这条线压力极限比例高于2.5，这意味着涡轮增压器驱动飙升，事实上，它甚至可以破坏增压器，使整个系统无法正常工作。当使用新设计的压缩机时,可以看出在高压压缩机的稳定的流动范围比是有效地扩大和操作线在整个压缩机喘振线的右边的图上。有涡轮增压器没有激增，它满足了车辆发动机对于跨声速流离心压缩机的范围要求。这种涡轮增压器已成功应用于几种高功率密度发动机的车辆。

5 结论

在这篇论文中，高压缩比跨声速离心涡轮压缩先进的开发过程，适应大流量范围要求的充电汽车内燃机，彻底从最初提出了一维计算机辅助设计参数分析样机制造和测试实验结果表明,该过程是成功的最大压力峰值比率约为4.2，最大效率高于80%。设计速度使稳定流量范围扩展了34%。实现参数满足今天的最高要求涡轮增压器技术促进高水平

的EGR技术和体积缩小提供体现与设计可行的成本效益规模制造的高很多。这种高压比的涡轮增压器已被应用在一些车辆研究中，并提高了40%的功率。

这项工作得到了国家自然科学基金(批准号50806040)和专门研究高等教育的博士项目基金)(批准号200800031075)的支持。这项工作也得到了国家柴油机涡轮增压技术重点实验室基金的支持。 6 参考文献

1 贝恩斯N c .涡轮增压器的基础。波士顿:概念公司,2005年版；

2 霍利JG，WallaceFJ，Coxl A等。美国《机械工程学会会报》出版的可变几何涡轮，低排放，改善转矩特性。

3 Clenci A C，Descombes G，Podevin P等。美国《机械工程学会会报》出版的关于某些方面与涡轮增压减小的结合，变量压缩率和可变气门升程。

４ Maiboom A, Tauzia X, Héteta J F。实验研究直入柴油发动机各种废气再循环（EGR）对燃烧的影响和汽车的工作联系。能源，2008，33（1）：22-44

5 罗杰斯c .涡轮增压高空无人机C.I.引擎。大学学报论文2001 - 3970号,2001年 6 Krain H, Karpinski G, Beversdorff M。在跨声速流分析离心压缩机转子使用三分量激光测速。ASME2001 – GT - 0315号2001

7 Hirotaka H, Kiyoshi H, Kunio S, et al。马赫的详细流程研究 随着压力比的冲击波数

1.6高跨音速流动 11离心压缩机叶轮。 ASMEĴTURBOMACH，2004年， 126（4）：473-481

8 Hunziker R, Jacoby P, Meier A. 新系列的小型涡轮增压器比率高流量和高压力。Motortechnische 杂志,2002,63(6):10 – 13

9 Zheng X Q, Zhang Y J, Guo G D, et al。车辆跨音速离心压缩机的设计。J航天实力,2008,23(10):1903 – 1907

10 Spalart P R, Allmaras S R。一个方程湍流模型空气动力流。大学学报论文92 - 0439号,92年

专业英语大作业篇三

专业英语课程翻译大作业模板

《专业英语》课程翻译大作业

班级： 姓名： 学号： 任课教师：张 磊 成绩：

专业英语大作业篇四

专业英语大作业1

Audio Amplifiers

For those of you who like to experiment with audio circuits and would like a simple amplifier that frees you from having to figure out the biasing resistors, we have two for you (and they run off 9 Volts too!). One uses an Op-Amp (Fig 4.9 (a)) and the other uses a transistor (Fig 4.9(b)).

(a) Op-Amp (b) Transistor Amp

Fig 4.9 two audio amplifiers

Both circuits need capacitors on the input and output to block DC while passing AC. The capacitor values depend on which circuit you use and what signal frequency you are amplifying. Start with a 1F and go from there. Low frequencies may require a bigger value.

While Op-Amps normally run off of a dual voltage supply (+U and -U), it is possible to run them from a single voltage by using two equal value resistors (Rb) to create a separate DC grounding point midway between UCC and actual ground, just for biasing the Op-Amp.

The DC ground is connected to actual ground through a by-pass

capacitor. The value of Rb is not critical; 10k should work just fine. To

minimize DC offset in the output, Rb should have a 1% tolerance.

The gain of the amplifier is set by R1 and R2 （AV = R2/R1）. R2 should be at least 2k or bigger so as not to load the Op-Amp too much. If you use a bipolar device such as the venerable 741, the output can't go lower than 2 volts above ground or higher than 2 volts below UCC. So with a 9-volt battery, the maximum output swing will be 5 volts: from 2V to 7V. If you want to go "rail-to-rail" from UCC to Ground, then use a CMOS device like the CA3130; UCC can then be as high as the Op-Amp allows. The CA3130 requires a 100 pF compensation capacitor.

If you really want "quick and dirty", this one transistor circuit is an ''oldie but goodie''. (See Fig4.9 (b)). Note that by connecting the base-bias resistor Rb to the collector you get two benefits:

1) the biasing cannot cause saturation or cut-off and

2) you introduce some negative feedback into the signal path, which reduces distortion.

It's not as good as the Op-Amp circuit but it does work. As for gain, you'll just have to measure it and see. Play around with different values of Rc, and make Rb= 100Rc. The voltage peak of input signal should not exceed 15mV.

专业英语大作业篇五

专业英语大作业

Study on the Ability of Tolerance of the Long-term Vibration of

Ancient Architecture

With the constant expanding of the present city construction scale, the influence of traffic vibration and industry vibration on the ancient architecture is inevitable and increasing ,which is a long-term process and every day for a long time.long-term accumulation, fatigue damage, safety performance degradation and other aspects of the building can not be ignored even if not enough has significant effect on buildings in a short period of time.The subject main to study the ability of ancient architecture to tolerate long-term vibration in which AHP and durability research based on neural network method are applied to the research on the durability of the ancient buildings.It has the profound significance to the study of ancient architecture。

Domestic experts and scholars have carried out a lot of research on the historic building fire prevention, an example is that Beijing Jiaotong University, Tongji University ,etc. were carried out to study the effects on surrounding buildings which caused by the subway.Study on prediction of timbered ancient building’s life also gradually rich, such as the application of the knowledge of BP neural network to the life prediction of timbered ancient buildings.AHP is widely used in evaluating the durability of the concrete structure, concrete structure durability research based on neural network is also more and more, such as bridges and frame structure, and have achieved good results, but these methods are seldom used in ancient architecture.Therefore ,we can use the hierarchical analysis method and neural network theory for reference to study the ability to tolerate long-term vibration of ancient buildings.

The method is mainly based on the hierarchical analysis of the layered method principle, determine the relevant factors, such as component to their own situation, historical situation, the environmental factors such as long-term vibration which were main consideration: traffic vibration, mechanical vibration, vibration during construction, then setting up the hierarchy structure.Secondly, to construct the multiple comparison judgment matrix and test of judgment matrix so to establish the analysis model of buildings durability evaluation level.Then combining with the existing data and the literature to determine the evaluation index grade standard and determine the weight of each index in the evaluation system, so as to get the comprehensive evaluation index.Durability research based on neural network method is quantitative

characteristics of ancient building durability upper bearing structure as the input of the network, several grades of the assessment results of durability as output of network. The network is trained using the training set LVQ data to the design, then the test set data were tested, and the test results were analyzed, including LVQ neural network implemented by MATLAB.Finally,contrast the results of two methods.If we can get the expected effect, not only can the long-term anti-vibration ability of ancient buildings have a more in-depth understanding, provides a new method to the research on the durability of the ancient architecture, but also provide the basis for the protection and repair of ancient buildings.

专业英语大作业篇六

专业英语大作业封面(2013版)

上海电力学院

专业英语大作业

姓名： 学号： 班级：

计算机科学与技术学院