驻波英文论文

音频信号处理博士论文中英文资料外文翻
译文献
音频信号处理是一个广泛研究的领域，涉及到音频信号的获取、分析、传输和处理等方面。

本文翻译了以下两篇外文文献，为音频
信号处理博士论文的写作提供参考。

文献一：Title of Paper One
作者：
摘要：
该篇文献提出了一种新的音频信号处理算法，旨在改善音频信
号的质量和增强用户对音乐的感受。

通过对音频信号进行特征提取
和分析，该算法能够有效地消除噪音和失真，并提供更清晰、更丰
富的音频体验。

文献介绍了算法的原理和实现方式，并通过实验验
证了其在不同音频数据集上的有效性。

文献二：Title of Paper Two
作者：
摘要：
该篇文献探讨了音频信号处理领域的一个重要问题，即语音识
别的准确性和鲁棒性。

通过分析现有的语音识别算法，文献指出了
当前算法存在的一些问题，并提出了一种改进的方法。

该方法基于
深度研究和卷积神经网络，并通过对音频信号进行多层次的特征研
究和表示研究，提高了语音识别的准确性和鲁棒性。

文献还介绍了
该方法的实验结果，并与其他算法进行了比较。

总结
这两篇外文文献介绍了音频信号处理领域的一些重要研究进展
和算法。

它们提供了宝贵的参考和借鉴，可以在音频信号处理博士
论文的写作中起到指导作用。

通过综合运用这些研究成果，我们可
以进一步改进音频信号处理算法，提高音频信号的质量和用户体验。

测量技术论文六篇测量技术论文范文1由于小功率信号计量校准技术特别成熟，测量方法和测量设备都特别完善，测量不确定度也很小。

相比小功率信号，大功率信号热效应显著、非线性特性显著，模型很难建立。

大功率部件稳定性差，离散性大，直接校准特别困难，因此如何把大功率信号不失真地转化为标准的小功率信号，利用已建立的小功率计量标准开展精确量传就成为关键问题。

首先，我们需要讨论和分析定向耦合器链路的温度特性、电性能特性。

3．1定向耦合器功率－温度特性试验我们利用功率计、定向耦合器、大功率负载、功率放大器、非接触温度测量仪等构建了一套简洁的功率－温度特性试验系统。

给系统加不同的功率，在此功率下稳定一段时间，监测定向耦合器输入端、耦合端、输出端和负载输入端附件的温度。

试验数据见表2。

从试验分析可以得出以下结论。

1)整个链路施加功率时，定向耦合器整体发热量很小，温升变化(21℃～26℃)，温度变化很小;2)系统选用的27000(同轴)500W 定向耦合器，在常温下，链路承受功率小于50W时，链路上各监测点的温度都变化不大，在5min内都达到了温度平衡状态;3)链路功率大于50W时，链路上定向耦合器各监测点的温度变化不大，但负载检测点温度变化较大，需要15min才能达到热平衡;4)链路上热量主要集中在负载部位，负载的材料的热导率很高，导热效果很好，但对邻近的定向耦合器输出端口温度影响很小，因此定向耦合器的小功率和大功率状态下的温度比较稳定。

3．2定向耦合器电性能－温度特性试验依据定向耦合器功率－温度特性试验中，系统加不同功率功率后稳定的温度，我们利用矢量网络分析仪、定向耦合器、大功率负载、温箱等构建了一套简洁的电特性－温度特性试验系统，进行环境模拟试验，试验的温度箱设置温度根据上面的大功率试验猎取的链路温度来设定，试验温度变化间隔一般小于5℃，以猎取大功率计量校准链路温度变化对电参数特性的影响，测量耦合度和驻波比等性能来评估系统。

附录A 英文原文Radio Frequency and Microwave ApplicationsA.1 IntroductionThis chapter lays the foundation for understanding higher-frequency wave phenomena and divides the task of active circuit design for RE/MV frequencies into specific concept blocks. These concept blocks create a gradual approach to understanding and designing RF/MW circuits and represent specific realms of knowledge that need to be mastered to become an accomplished designer.Before we describe and analyze these types of waves we need to consider why RF/microwaves as a subject has become so important, that it is placed at the forefront of our modern technology. Furthermore, we need to expand our minds to the many possibilities that these signals can provide for peaceful practices by exploring various commercial applications useful to mankind.A 1.1 A Short History of RF and MicrowavesCirca 1864—1873, James Clark Maxwell integrated the entirety of man’s knowledge of electricity and magnetism by introducing a set of four coherent and self-consistent equations that describe the behavior of electric and magnetic fields on a classical level. This wav the beginning of microwave engineering, as presented in a treatise by Maxwell at that time .He predicted, purely from a mathematical standpoint and on a theoretical basis, the existence of electromagnetic wave propagation and that light was also a from of electromagnetic energy —both completely new concepts at the time.From 1885 to 1887, Oliver Heaviside simplified Maxwell’s work in his publish ed papers. From 1887 to 1891, a German physics professor, Heinrich Hertz, verified Maxwell’s predictions experimentally and demonstrated the propagation of electromagnetic wave. He also investigated wave propagation phenomena along transmission line and antennas and developed several useful structures. He could be called the first microwave engineer.Marconi tried to commercialize radio at a much lower frequency for long-distance communications, but as he had a business interest in all of his work and developments, this was not a purely scientific endeavor.Neither Hertz nor Heaviside investigated the possibility of electromagnetic wave propagation inside a hollow metal tube because it was felt that two conductors were necessary for the transfer of electromagnetic wave or energy. In 1897, Lord Rayleigh showed mathematically that electromagnetic wave propagation was possible in wave-guides, both circular and rectangular. He showed that there are infinite sets of modes of the TE and TM type possible, each with its own cut-off frequency. These were all theoretical predictions with no experimental verifications.From 1897 to 1936, the wave-guide was essentially forgotten until two men, George Southworth (AT&T) and W. L. Barron (MIT), who showed experimentally that a wave-guide could be used as small bandwidth transmission medium, capable of carrying high power signals.With the invention of the transistor in the 1950s and the advent of microwave integrated circuits in the 1960s, the concept of a microwave system on a chip became a reality. There have been many other developments, mostly in terms of application mass, that have made RF and microwave an enormously useful and popular subject. Maxwell’s equations laid the foundation and laws of the science of electromagnetic, of which the field of RF and microwave is a small subset. Due to the exact and all-encompassing nature of these laws in predicting electromagnetic phenomena, along with the great body of analytical and experimental investigations performed since then, we can consider the field of RF and microwave engineering a “mature discipline” at this time.A.1.2 Applications of Maxwell’s EquationsAs indicated earlier in Chapter 2, Fundamental Concepts in Electrical and Electronics Engineering, standard circuit theory can neither be use at RF nor particularly at microwave frequencies. This is because the dimensions of the device or components are comparable to the wavelength, which means that phase of an electrical signal (e.g., a current or voltage) changes significantly over the physical length of the device or component. Thus use ofMaxwell’s equations at these higher frequencies becomes imperative.In contrast, the signal wavelengths at lower frequencies are so much larger than the device or component dimensions, that these are negligible variation in phase across the dimensions of the circuit. Thus Maxwell’s equations simplify into basic circuit theory, as covered in Chapter 3, Mathematical Foundation for Understanding Circuits.At the other extreme of the frequency range lies the optical field, where the wavelength is much smaller than the device or circuit dimensions. In this case, Maxwell’s equations simplify into a subject commonly referred to as geometrical optics, which treats light as a ray traveling on a straight line.These optical techniques may be applied successfully to the analysis of very high microwave frequencies (e.g., high millimeter wave range),where they are referred to as “quasi-optical.” Of course, it should be noted that further application of Maxwell’s equation leads to an advanced field of optics called “physical apices or Fourier optics,” which treats light as a wave and explains such phenomena as diffraction and interference, where geometrical optics fails completely.The important conclusion to be drawn from this discussion is that Maxwell’s equations present a unified theory of analysis for any system at any frequency, provided we use appropriate simplifications when the wavelengths involved are much larger, comparable to, or much smaller than the circuit dimensions.A.1.2 Properties of RF and MicrowavesAn important property of signals at RF, and particularly at higher microwave frequencies, is their great capacity to carry information. This is due to the large bandwidths available at these high frequencies. For example, a 10 percent bandwidth at 60MHz carrier signal is 6MHz, which is approximately one TV channel of information; on the other hand 10 percent of a microwave carrier signals at 60 GHz is 6GHz, which is equivalent to 1000 TV channels.Another property of microwaves is that they travel by line of sight, very much like the traveling of light rays, as described in the field of geometrical optics. Furthermore, unlike lower-frequency signals, microwave signals are not bent by ionosphere. Thus use of line-of-sight communication towers or links on the ground and orbiting satellites around theglobe are a necessity for local or global communications.A very important civilian as well as military instrument is radar. The concept of radar is based on radar cross-section which is the effective reflection area of the target. A target’s visibility greatly depends on the target’s electrical size, which is a function of the incident signal’s wavel ength. Microwave frequency is the ideal signal band for radar applications. Of course, another important advantage of use of microwaves in radars is the availability of higher antenna gain as the frequency is increased for a given physical antenna size. This is because the antenna gain being proportional to the electrical size of the antenna becomes larger as frequency is increased in the microwave band. The key factor in all this is that microwave signal wavelengths in radars are comparable to the physical size of the transmitting antenna as well as the target.There is a fourth and yet very important property of microwaves; the molecular, atomic, and nuclear resonance of conductive materials and substances when exposed to microwave fields. This property creates a wide variety of applications. For example, because almost all biological units are composed predominantly of water and water is a good conductor, microwave technology has tremendous importance in the fields of detection, diagnostics, and treatment of biological problems or medical investigations (e.g., diathermy, scanning, etc.). There are other areas in which this basic property would create a variety of applications such as remote sensing, heating (e.g., industrial purification and cooking) and many others are listed in a later section.A.2 Reasons for Using RF/MicrowavesOver the past several decades, there has been a growing trend toward use of RF/microwaves in system applications. There are many reasons among which the following are prominent:Wider bandwidths due to higher frequencySmaller component size leading to smaller systemsMore available and less crowded frequency spectrumLower interference due to lower signal crowdingHigher speed of operationHigher antenna gain possible in a smaller spaceOn the other hand, there are some disadvantages to using RF/microwaves, such as: more expensive components, availability of lower power levels, existence of higher signal losses, and use of high-speed semiconductors (such as GaAs or INP) along with their corresponding less-mature technology (relative to the traditional silicon technology, which is now quite mature and less expensive).In many RF/microwave applications the advantages of a system operating at these frequencies outweigh the disadvantages and propel engineers to a high-frequency design.A.3 RF/Microwave ApplicationsThe major applications of RF/microwave signals can be categorized as follows:A.3.1 CommunicationThis application includes satellite, space, long-distance telephone, marine, cellular telephone, data, mobile phone, aircraft, vehicle, personal, and wireless local area network (WLAN), among others. Two important subcategories of applications need to be considered: TV and radio broadcast, and optical communications.TV and radio broadcastIn this application, RF/microwaves are used as the carrier signal for audio and video signals. An example is the Direct Broadcast System (DBS), which is designed to link satellites directly to home users.Optical communicationsIn this application, a microwave modulator is used in the transmitting side of a low-loss optical fiber with a microwave demodulator at the other end. The microwave signal acts as a modulating signal with the optical signal as the carrier. Optical communication is useful in cases where a much larger number of frequency channels and less interference from outside electromagnetic radiation are desired. Current applications include telephone cables, computer network links, low-noise transmission lines, and so on.A.3.2 RadarThis application includes air defense, aircraft/ship guidance, smart weapons, police, weather, collision avoidance, and imaging.A.3.3 NavigationThis application is used for orientation and guidance of aircraft, ships, and land vehicles. Particular applications in this area as follow:Microwave Landing System (MLS), used to guide aircraft to land safely at airportsGlobal Positioning System (GPS), used to find one’s exact coordinates on the globeA.3.4 Remote SensingIn this application, many satellites are used to monitor the globe constantly for weather conditions, meteorology, ozone, soil moisture, agriculture, crop protection from frost, forests, snow thickness, icebergs, and other factors such as monitoring and exploration of natural resources.A.3.5 Domestic and industrial ApplicationsThis application includes microwave ovens, microwave clothes dryers, fluid heating systems, moisture sensors, tank gauges, automatic door openers, automatic toll collection, highway traffic monitoring and control, chip defect detection, flow meters, power transmission in space, food preservation, pest control, and so onA.3.6 Wireless ApplicationsShort-distance communication inside as well as between buildings in a local area network (LAN) arrangement can be accomplished using RF and microwaves. Connecting buildings via cables (e.g., coax or fiber optic) creates serious problems in congested metropolitan areas because the cable has to be run underground from the upper floors of one building to the upper floors of the other. This problem, however, can be greatly alleviated using RF and microwave transmitter/receiver systems that are mounted on rooftops or in office windows. Inside buildings, RF and microwaves can be used effectively to create a wireless LAN in order to connect telephones, computers, and various LANs to each other.Using wireless LANs has a major advantage in office rearrangement where phones, computers, and partitions are easily moved with no change in wiring in the wall outlets. This creates enormous flexibility and cost savings for any business entity.附录B中文翻译射频与微波应用B.1 引言本章为理解更高频率的颠簸现象奠定了基础，这里我们将射频/微波频端的有源电路的设计分为不同的概念模块，他们以循序渐进的方式出现，以便我们理解和设计射频/微波电路，并且该部分内容也是一个熟练设计的人员所必须掌握的知识领域。

Vehicle noise vibration and harshnessAbstractVehicle noise, vibration and harshness (NVH) is usually the major attribute because of its priority in the design of vehicles. NVH affects the design and manufacture process of a vehicle as higher customer satisfaction are attributed by a good NVH behavior. The research on NVH relies on a variety of computer software to improve and control NVH. In this paper, several vehicle components including rubber dampers and isolators which play an important role in controlling the NVH are presented. A description of source of NVH in a vehicle is shown.Keywords: NVH; rubber damper; isolator; research.1. IntroductionVehicles consist of space vehicles, airplanes, submarines, trains, road, off-road and others [1]. Vehicle noise, vibration, and harshness (NVH) is a major problem in the automobile manufacturing process and affects the customer satisfaction of automobile owners. The researches of vehicle noise, vibration, and harshness (NVH) are not only suitable for the design process of new automobiles, but contribute to improve the comfort and performance of current type of automobiles. Those researches are largely due to the increasing demands of vehicle manufacturers, Original Equipment Manufacturers (OEMs) and customers. The OEMs aim to look for the products that address issues of NVH, reduce vehicle weight, improve stiffness, and are easy to model, lower costs, and are environmentally friendly [2]. Automotive noise, vibration and harshness are the most important issues when the customers assess vehicle quality [1]. On the other hand, some manufacturers refuse to corporate automation into vehicle design, as addressing the issues of NVH which makes vehicles too quiet may pose a threat to the safety of pedestrians [4]. The vehicular noise can act as a warning signal for pedestrians.Some components in the vehicles play important roles in reducing NVH, namely rubber dampers, the power plants, chassis coupling, and elastomeric isolators.Rubber dampers insert between the fins and rubber dampers reduce the amplitude of vibration of fins which are used to speed up the heat transfer from the engine surfaces [3].In vehicles, the engine mounts affect largely the noise, vibration, and harshness comfort. The mounts are used to provide supports for the power plant and to isolate the vibrations of the power plant from the rest of the vehicles [6].A multiplicity of elastomeric isolators is needed, including engine mounts, suspension bushings, and frame and sub frame mounts [5]. Some functional requirements for isolators involve steering, braking, package, and durability, although these desired characteristics conflict frequently.2. The research on NVHFor vehicles, the issue of vibration, noise, and harshness (NVH) exists mainly in the engine, car body, and engine mounts. During the working of these components, they are affected by aerodynamic (NVH), air-conditioning system (NVH) and brake system (NVH). Vehicle NVH emphasis the feeling of human beings for vibration and noise and cannot be measured directly. The research on NVH consists of the comfort of passengers in vehicles and intensity problems of vehicle s’components caused by vibration. The research on the characters of vehicle NVH should concentrate on entire cars and separate entire cars into subsystems, such as engine system, engine mount system and car body system.The issue of vehicle NVH is not caused by relatively several reasons rather than simply one reason. For instance, the noise in the car may be due to the high level of noise of the engine, the pour isolation effect of suspension around the engine, or limited technology of sound-proofing between the car body and power system.There are some basic theories and methodologies helping understand and study the character of NVH.Finite element methods are to separate continuous elastomer into the limited number of units and calculate the system deformation, stress, and dynamics character through the finite element models on the computer. Because of the rapid development of finite element methods and the maturity of relative analysis software, FEM has become an essential method to analyze the character of vehicle NVH. FEM is suitable for the modeling analysis of vehicle body structure vibration and car interior cavity noise. On the other hand, combining FEM with multi-system dynamics to analyze engine mount system can increase the accuracy of dynamic character of the engine mount.BEM is short for the blade element momentum. Compared with FEM, BEM decreases the dimension of questions, making it convenient to handle the issues of unlimited field and establish the efficient network on the computer. The BEM theory is greatly employed for practical engineering application, especially in the field of NVH [16]. The shortage of BEM to address the problem of NVH is low speed of calculation.Experimental transfer path analysis (TPA) is a fairly well established technique for estimating and ranking individual low-frequency noise or vibration contributions via the different structural transmission paths from point-coupled powertrain or wheel suspensions to the vehicle body [11]. Experimental transfer path analysis is a favored technique to investigate further possibilities to fine-tune the rubber components of the engine and wheel suspension with respect to NVH.The experimental transfer path analysis method involves an indirect measurement procedure for estimating operating force components acting at the coupled DOFs (degree of freedom). TPA also involves a direct measurement of all transfer frequency response functions between response in points of interest and points where these forces act [11].Design of experiments method (DOE) can be used to minimize the transmittedengine- induced harshness to the body and improve a vehicle body structure. The DOE method includes factorial and response surface methods. The surface modeling is accomplished for the vehicle body with CATIA and HYPERMESH software which is used to create and optimize the FEA modal. NASTRAN software is used to analyze the modal in a frequency range between 0-50Hz [17, 18].3. The effect of rubber dampers on NVHThe rubber damper is an important type of equipment to reduce noise, vibration, and harshness (NVH), widely being used in a number of machines, vehicles, trains and aircrafts. The popularity of rubber dampers is due to the characteristics of rubber with high visco-elasticity and high elasticity. Compared with steel, elastic deformation of rubber is large and elasticity modulus of rubber is small. As well, rubber is considered as incompressible material.The function of rubber dampers between the fins is to make a compromise between vibration amplitude increases and fin base temperature decreases. Through the research on the effect of rubber dampers on the radiated noise from engine, it is concluded that the effect of the rubber dampers is to reduce engine high frequency noise level, which means the problem of vehicle noise vibration and harshness can be partly handled by using the rubber dampers. Engineers continue to work on the issues of high vehicle noise vibration and harshness when an engine does not rubber dampers with two methods. These two approaches are related to structural noise problems.The first method is to find ways of reducing the sound power by passive means and the other method is to use active control approaches. Compared with active control solutions which may be suitable in the future, passive control should not be ignored as it is useful for high frequency noise [3].Rubber dampers are not the only equipment using rubber in vehicles and some rubber connections are widely employed for structural parts. A change in rubber joint material properties can help evaluate the sensitivity of the full-scale system vehicle noise vibration and harshness (NVH) [7]. A three level modeling approach with a material, a component, and a system level has been introduced to evaluate the sensitivity of the NVH.4. powerplant mounting system NVHThe basic function of engine mount is to support the weight of power train and to isolate the vibration and harshness transmission from engine to body, to segregate the transmission from road surface excitation to power train [8]. As well, in order to lighten the car body, increase power-intensive engine and require vibration, noise, and harshness isolation for passenger cars, the performance of the powerplant mount system need to be improved. Many factors, such as the engine layout state, the supporting positions of chassis mount, the fixed positions on the cylinder of the mount and the layout of surrounding parts, should be considered before the designation of engine mount [9].The responses of the powerplant mounting system to low frequency vibrations are important for improving the NVH in terms of rigidity and damping. Some designs of powerplant mounting system try to handle the issues of NVH by concentrating on the positioning and design of resilient supports. However they fail to consider chassis and suspension system interactions as these designs are based on decoupling rigid body modes from a grounded powerplant mode.Fig.1. Powerplant mounting systemThe traditional engine mount design strategies consider only the rigid body modes of a grounded engine and arrangements of powerplant rigid body mode [6]. When considered as a rigid body, three translational modes and three rotational modes of frame represent the vibration, noise, and harshness (NVH) of powerplant using dynamic decoupling method. In detail, three translational modes are bounce, lateral, and longitudinal vibrations and three rotational modes are called by rotations about pitch, roll and yaw. It is believed that the vibration, noise and harshness (NVH) transferred to the car body structure can be reduced by conditioning the powerplant mounting system such that the powerplant oscillates about the torque axis [10]. The torque roll axis decoupling strategy controls the displacement of the uncoupled blocked powerplant. With less displacement of the powerplant, the level of NVH is reduced [6].The traditional design strategies sometimes may not put the issues of vehicle vibration noise and harshness (NVH) into consideration. With the development of technology and increasing demands of customers for comfort, the manufacturers and automobile companies begin to pay attention to design new powerplant mounting system. The current powerplant mounting strategies examine the rigid-body modes of the power train as it would sit on the mounts attached to the ground and neglect the effect of the chassis. The current engine mount system has achieved the goal that makes sure the driver and the passengers isolate from vibration noise and harshness (NVH) generated by the engine.5. Isolator on NVHElastomeric isolator and hydraulic isolator are widely used in automotive vehicle including shock absorbers, engine mounts and body mounts. Isolators can reduce vibrations and improve the ride performance experienced by drivers and passengers. Noise, vibration and harshness (NVH) are important to the consumer s’acceptance of a vehicle. Isolator s’type, sizing and placement are critical to NVH design [13]. The difference between elastomericisolator and hydraulic isolator is that hydraulic isolators are frequency dependent and elastomeric isolators are independent of frequency. It is largely because they use different mediums to dissipate mechanical energy.A hydraulic isolator connects a vibrating body and an isolated body in a vehicle and consists of a cylinder with two chambers and a piston. An electronic control system is required to cooperate with hydraulic isolator to supply an alternating current of appropriate amplitude and phase to several magnetic coils disposed adjacent to the tuning slug [12]. Matching the isolation frequency with the vibration frequency and adding energy to the vibration isolator to compensate for damping losses is the basic theory how no vibration is transferred from the vibrating body to the isolated body with the help of hydraulic isolator.Fig 4.1 hydraulic isolatorThe elastomeric isolators in the vehicles are separated into two kinds, namely rubber isolator and metal-net isolator. They are used for engines, especially for large power diesel engine. The metal-net isolator with the characters of nonlinear stiffness, large damping and power circumstance adaptability has advantages over rubber isolator and can be used as diesel engine’s mount component.Rubber isolators have been used in NVH control for years. Rubber is hyper elastic material and its suitability as isolator is due to good flexibility and resilience characteristics [14, 15].Rubber isolators cannot be used in low, high temperature, erode and toughcircumstance, e.g. in low temperature, rubber isolators have no isolating effect causing the aggravation of NVH and also can only isolate a single frequency vibration in any circumstance. It is due to the traditional design depending on experience and repeat experiment. Modern rubber isolator is designed with finite element method [14]. A modern rubber isolator is composed of steel and rubber. What differentiate modern isolator rubbers from traditional rubbers is that there are several holes. Those holes can effectively change the static and dynamic characteristics of rubber isolators. As a result, it manages to improve NVH with the improvement of performance of rubber isolatorsFig 4.2 rubber isolatorA metal-net isolator consists of the stainless steel web and the metal wire. When the force is on the stainless steel web, the metal wire slides and results in dry friction damping that absorbs and consumes the energy of system to approach isolating and cushion aims. The isolator’s elastic character is nonlinear, which has higher carrying capacity. Active isolation and passive isolation are two kinds of ways to isolate vibration with the use of metal-net isolator. Active isolation reduces vibration by isolating machine from vibration source and passive isolation relaxes the effect of external vibration [10].Fig 4.3 metal-net isolatorCompared rubber isolator with metal-net isolator, the transfer rate of metal isolator is smaller than that of rubber isolator, which means metal-net isolator has more ability to control NVH and absorb energy.6. ConclusionVehicle vibration, noise and harshness (NVH) has been receiving considerable attention for many years. The main sources of usual NVH are power engine, brake, suspension system, the steering system as well as other hardware of the vehicle. Also, the road NVH and wind NVH has become important issues as they dominate the medium and high speed ranges. In order to improve NVH, the performance of rubber dampers and isolator should be taken measured to improve.The paper gives a brief description of the current research of NVH, several modern methods such as finite element method and blade element momentum have already put into use. These methods greatly increase the accuracy and efficiency when addressing the issues of NVH.Two major components in a vehicle used to control NVH are introduced in the paper, namely rubber damper and isolator. The effect of rubber dampers is to isolate the engine NVH. Isolators are widely used in a vehicle and can be separated as elastomeric isolator and hydraulic isolator. The metal-net isolator has more advantage than rubber dampers. Engine and engine mount are the main sources of NVH. Some traditional engine mounting systems have shortages in design and manufacture.References[1] Mohamad, S. Qatu. “R ecent research on vehicle noise and vibration” , Int. J. Vehicle Noise and Vibration, Vol. 8, No.4, (2012).[2] Anita Carey and Kurt Lilley. Considering and comparing sealant option: a variety of cost-effective solutions, 2002.[3] Singh, O.P., Sreenivasulu, T., Kannan, M. “The effect of rubber dampers on engine’s NVH and thermal performance” , Applied Acoustics 75 17-26 (2014).[4] Nicholas D. Cottrell and Benjamin K. Barton. “The impact of artificial vehicle sounds for pedestrians on driver stress”,Ergonomics, Vol.55, 1476-1486 (2012).[5] Himes, R.S. and David Griffiths. “Future vehicle noise, vibration and harshness requirements for elastomeric isolators”, the Detroit Rubber Group meetin g, Detroit, the USA, September 2000[6] Courteille, E., Leotoing, L., Mortier, F. and Ragnean, E. “New analytical method to evaluate the power plant and chassis coupling in the improvement vehicle NVH”, European Journal of Mechanics A/Solids 24, 929-943 (2005). [7] Stenti, A., Moens, D., Sas, P. and Desmet, W. “A three-level non-deterministic modeling methodology for the NVH behavior of rubber connections” , Journal of Sound and Vibration 329 912-930 (2010).[8] Haran Periyathamby, Michael E. Anderson, David A. Nash and Y. Charles Lu. “NVH characteristics of thermoplastic composite engine covers”, Int. J. Vehicle Noise and Vibration, Vol. 5, No. 3, (2009).[9] Xiangming QIAN. “Research on Structural Design of Vehicle Engine Mount” , IEEE, 978-1-4577-0536-6/11 (2011).[10] Wenbing YAN, Shaozhong JIANG, Yujun CAI, Lizhi WEN and Yue CHEN. “Experimental Study of Engine Mount System’s Vibration Characteristics”, World Congress on Software Engineering, Tianjing, China, 2009.[11] Juha Plunt. “Finding and Fixing Vehicle NVH Problems with Transfer Path Analysis”, the Noise & Vibration Conference, Traverse City, MI, 16-19 May,.2005.[12] Zhixing Li, Shijian Zhu, Jingjun Lou and Simi Tang. “Simulation on Performance of Rubber Isolator Based on ANSYS”IEEE 978-1-4244-9439-2/11 (2011)[13] Chen-Ron Lin and Yu-Der Lee. “Effects of viscoelasticity on rubber vibration isolator design” , Journal of Applied Physics 83, 8027 (1998).[14] Dai, J.C., Hu, Y.P., Liu, D.S. and Long X. “Aerodynamic loads calculation and analysis for large scale wind turbine based on combing BEM modified theory with dynamic stall model” , Renewable Energy 36, 1095-1104 (2011). [15] Shahram Azadi, Mohammad Azadi and Farshad Zahedi. “NVH analysis and improvement of a vehicle body structure using DOE method” , Journal of Mechanical Science and Technology23, 2980-2989 (2009).[16] Shariyat, M. and Djamshidi, P. “Minimizing the Engine-induced Harshness Based on the DOE Method and Sensitivity Analysis of the Full Vehicle NVH Model”, International Journal of Automotive Technology, Vol. 10, No,6, pp. 687-696 (2009)...。

ANSYS 2011中国用户大会优秀论文Ansoft HFSS在设计对数周期天线时的仿真方法孙凤林黄克猛中国西南电子技术研究所，成都，610036[ 摘要 ] 本文通过ANSOFT HFSS设计了一个对数周期天线，在仿真分析时，发现随着求解频率的不同，天线的求解结果差别较大，求解误差较大。

通过在HFSS中尝试不同的求解设置方法，最终通过将天线模型剖分网格最大长度限定在1/50λ的方法，使的求解结果在不同频率求解时的一致性较好，提高了仿真的准确性。

为设计者在仿真类似问题时，提供了一种提高求解准确性的方法。

[ 关键词]HFSS；网格设置；对数周期天线The Simulation Method on designing of a Log-PeriodicDipole Antenna on Ansoft HFSSSun Feng-lin，Huang Ke-mengSouthwest China Institute of Electronic Technology, Chengdu, 610036, China[ Abstract ] A method of simulating Log-Periodic Dipole Antenna on Ansoft HFSS is introduced in this paper. When simulating the Log-periodic antenna model, it was found that the simulationresults are difference with different Solution Frequency on HFSS, The solution error is high.The accuracy of the solution depends on the size of each of the individual elements, togenerate a precise simulation result, applying mesh operations ,assigning Maximum lengthof Elements mesh to 1/50λ, the results shows that the difference is reduced obviously, thesimulation accuracy is improved.[ Keyword ] HFSS; mesh operations; log-periodic dipole antenna1前言对数周期偶极子天线（log-periodic dipole antenna），由于其工作频带宽、增益高、前后比好、结构简单、成本低等众多优点，在短波、超短波、微波等波段的通信、侧向、侦察、电子对抗等方面得到了广泛的应用。

实验报告样本- 弦线上驻波实验题目:横波在弦线上的传播规律一、实验目的1.观察弦线上形成的驻波，用实验验证在频率一定时，驻波波长与张力的关系;2.在张力不变时，验证驻波波长与振动频率的关系;3.学习对数作图或最小二乘法进行数据处理;二、实验仪器可调频率的数显机械振动源、平台、固定滑轮、可调滑轮、砝码盘、米尺、弦线、砝码、电子秤等三、实验原理在一根拉紧的弦线上，沿弦线传播的横波满足运动方程:22,,yTy (1) ,22,,tx,22,,yyT2将该式与典型的波动方程比较，可得波的传播速度:，其中T为张,v,v22,,tx,力，线密度. 若波源的振动频率为f, 则横波的波长: , 1T (2) ,,,f两边取对数，得11,,,,, loglogloglogTf22,若固定频率f和线密度,，改变张力T，并测出各相应波长，作，若得loglog,,T1/2,,T,一直线，计算其斜率值，(如为1/2)，则证明的关系成立。

同理，固定线密度和,张力T，改变振动频率f，测出相应波长，作，如得一斜率为-1的直线就验loglog,,f,1证了。

,,f弦线上的波长可利用驻波原理测量。

当两个振幅和频率相同的相干波在同一直线上相向传播时，其所叠加而成的波称为驻波。

弦线上出现的静止点，称为波节，相邻两波节的距离,为半个波长。

若观察到在长为L的弦上有n个驻波，则波长=2L/n。

四、实验内容与步骤1. 验证频率一定时，横波波长与弦线上张力的关系选定一个波源振动频率并记录，改变砝码盘上所挂砝码的个数以改变张力(5次)。

每改变一次张力，均要移动可动滑轮的位置，使弦线上出现稳定且幅度比较大的驻波。

记录频率值，两支架间的距离L, L上所形成的半波数的个数n，以及砝码与砝码盘的总质量。

,,计算出波长(利用公式=2L/n)，张力(砝码与砝码盘所受的重力)，作log- logT图，计算其斜率，并于理论值比较。

2. 验证张力一定时，横波波长与波源频率的关系给砝码盘挂上一定数量砝码(一般三个)并记录，以保持张力一定。

内容摘要在建筑声学设计中，计算机辅助音质设计得到越来越广泛的应用。

本说明通过参照声学设计软件EASE3.0，参考音响工程设计与实例等，介绍了音响系统的结构、设计、安装与调试，并给出了演出大厅的设计方案。

本方案设计的是一个演出大厅，是一个带歌舞表演性质的场所，为双层演出大厅，要求具有舞蹈、唱歌、综合节目、播放20*6的LED显示屏以及小型电声乐队伴奏、钢琴弹奏等多种演出功能。

通过用EASE3.0对装修吸音材料、扬声器指向及功率等方面进行辅助设计使其混响时间和声压级的各项指标都能达到国家文化部发布的一级演出大厅要求,从而完成本次多功能演出大厅的设计和仿真。

关键字：EASE 音响设计演出大厅Content abstractIn the architectural acoustics design, computer aided quality design get applied more and more. This show that, through reference to acoustic design software EASE3.0, reference sound engineering design and the example, this paper introduces the structure of the sound system, design, installation and commissioning, and gives the performance hall design scheme.The plan is a performance hall, is a dance performance with the nature of the place, for double performance hall, requires a dance, sing and shows, played 20 * 6 of the LED display and small electro-acoustic band, piano and so on many kinds of performance function.Through the use EASE3.0 sound-absorbing materials for decoration, speaker and power to aspects of computer-aided design make its reverberation time harmonic level can meet all the indicators of national ministry of culture of the level of performance requirements issued by the hall so as to complete the multi-function performing hall design and simulation.Key word: EASE sound design performance hall目录内容摘要 (I)Content abstract (Ⅱ)目录 ............................................................................................................................................ I II 第一部分扩声系统设计的注意事项 (1)1、语言清晰度 (2)2、评价音质的各个指标 (2)3、音色—频率响应Tonal balance (2)第二部分演出大厅的设计方案 (3)一、演出大厅的设计 (3)二、演出大厅结构分析 (3)三、演出大厅主要音像设备的布局 (9)四、选配音箱 (12)五、选配功放 (13)六、其他设备的选配 (14)七、布线图 (15)八、系统结构图 (16)第三部分EASE仿真 (18)一.查看RT及房间容积 (18)二．查看演出大厅语言清晰度 (19)三．查看声场声压级分布图 (22)四.查看演出大厅模型渲染图 (24)第四部分音响调试 (25)总结 (27)参考文献 (28)-南通职业大学电子信息工程学院毕业设计方案第一部分扩声系统设计的注意事项众所周知，自然声源（如演讲、乐器演奏和演唱等）发出的声音能量十分有限，其声压级随传播距离的增大而迅速衰减。

1000字论文格式模板篇一：1000字论文范文3篇1000字论文范文3篇学位培养人才论文质量是评价教育硕士培养质量的重要指标之一,而论文选题又是教育硕士学位论文撰写的首要环节,是直接影响学位论文质量的更为重要。

本文是为大家收集整理的1000字的论文范文，仅供参考。

1000字论文范文篇一：在现代社会中，人与人之间的同居越来越密切。

当代人越发的感觉到人际交往的重要性。

人际交往是一个集体成长和社会发展的需要. 大学生的思考力社交能力普遍偏弱使得人际关系成为当务之急的一个课题.多年来,大学生长期在高考指挥棒下,过分注重追求成绩而忽视了人际交往等其他素质的培养.进入高校后,学交大也很少课程有专门的系统课程培训.所以导致一些大学生中学生智商很高,情商却很低,或者处理不好如何与其他人相处,沟通,交流. 我认为，人际交往时获取友谊的重要途径。

处于青年期的大学生，思想活跃、感情丰富，人际交往的需要极为令人不安，人人都渴望真诚友爱，大家都力图通过人际交往获得友谊，满足自己物质和精神上的需要。

校区内对于刚刚进入大学校园的新生，代莱群体的构成和紧张的社会群体学习生活，使得一部分学生由此而导致了心理矛盾的加剧。

此时，积极的人际交往，良好的人际关系，可以使人精神愉快，情绪饱满，充满信心，保持乐观的人生态度。

友好、和谐、协调的人际交往，这有利于大学生对不良情绪埃唐佩县和情。

在工作中同样如此，良好的人际关系能使我们能保持一个良好的心情，全身心的投入到组织工作中去"搞关系"算不上一个褒义词，很容易让人联想到"走后门"、"暗箱操作"等不光彩行为，但有一类人，他们的职责就是"搞关系"，这个关系"搞"得好不好，直接影响到企业的生产效益，这就是员工关系经理。

隔阂员工关系经理是个不太常见的头衔，只有在正规的私营企业、国企集团、合资企业中才能觅到他的踪影。

第一章1页1.1.1 Solid-state…固态材料可分为三种：绝缘体、半导体和导体。

图1-1给出了在三种材料中一些重要材料相关的电阻值（相应电导率）。

绝缘体如熔融石英和玻璃具有很低电导率，在10^-18到10^-8S/cm之间。

导体如铝和银有高的电导率，典型值从104到106S/cm;而半导体具有的电导率介乎于两者之间。

半导体的电导率一般对温度、光照、磁场和小的杂志原子非常敏感。

在电导率上的敏感变化使得半导体材料称为在电学应用上为最重要的材料。

3页1.1.2 The semiconductor…我们研究的半导体材料是单晶，也就是说，原子是按照三维周期形式排列。

在晶体中原子的周期排列称为晶格。

在晶体里，一个原子从不远离它确定位置。

与原子相关的热运动也是围绕在其位置附近。

对于给定的半导体，存在代表整个晶格的晶胞，通过在晶体中重复晶胞组成晶格。

6页1.1.3 As discussed…如1.1.2节所述，在金刚石结构的每个原子被4个相邻原子所包围。

每个原子在外轨道具有4个电子，并且每个电子与相邻原子共享价电子；每对电子组成一个共价键。

共价键存在于同种原子之间或具有相同外层电子结构的不同元素的原子间。

每个电子与每个原子核达到平衡需要相同时间。

然而，所有电子需要很多时间在两个原子核间达到平衡。

两个原子核对电子的吸引力保证两个原子在一起。

对于闪锌矿机构如砷化镓主要的价键引力主要来自于共价键。

当然，砷化镓也具有小的离子键引力即Ga+离子与四周As-离子，或As离子和四周Ga+离子。

7页1.1.4 The detailed…结晶固体的详细能带结构能够用量子理论计算而得。

图1-3是孤立硅原子的金刚石结构晶体形成的原理图。

每个孤立原子有不连续能带（在右图给出的两个能级）。

如原子间隔的减少，每个简并能级将分裂产生带。

在空间更多减少将导致能带从不连续能级到失去其特性并合并起来，产生一个简单的带。

当原子间距离接近金刚石结构的平衡原子间距（対硅而言晶格常数0.543nm）,这个带分为两个带区。

声学基础专业英⽂声学英⽂词彙声⾳，声学及其分⽀声⾳：sound可听声（阈）：audible sound超声：ultrasound次声：infrasound⽔声：underwater sound地声：underground sound噪声：noise声学：Acoustics物理声学：Physical Acoustics；⾮线性声学：Nonlinear Acoustics 超声学：Ultrasonics；次声学：Infrasonics；⽔声学：Underwater Acoustics⽓动声学：Aeroacoustics建筑声学：Architectural Acoustics；室內声学：Room Acoustics⾳乐声学：Musical Acoustics环境声学：Environmental Acoustics海洋声学：Oceanic Acoustics电声学：Electroacoustics语⾔声学：Speech Acoustics；语⾳信号处理：Speech Processing声信号处理：Acoustical Signal Processing光声学：Optoacoustics医学超声学：Medical Ultrasonics⽣物声学：Bioacoustics声化学：Sonochemistry⽣理声学：Physiological Acoustics；⼼理声学：Phsychoacoustics振动振动：vibration受迫振动：forced vibration阻尼振动弹性：elasticity劲度：stiffness；弹性常数：stiffness constant恢复⼒：restoration；张⼒：tension惯性，声质量：inertance⼒（机械）阻抗（阻，順，抗）：mechanical impedance (resistance, compliance, reactance)⼒导纳（导，納）：mechanical admittance, mobility (responsiveness, excitability)集总线路元件：lumped circuit elements共振：resonance；反共振：antiresonance参量共振：parametric resonance共鸣器，共振器：resonator亥姆霍茲共鸣器：Helmholtz resonator振⼦：oscillator激振器：vibrator隔振：isolation（阻抗型，导纳型）类⽐：(impedance-type, mobility-type) analogy摩擦（⼒）：friction (force)阻尼（系数）：damping (coefficient)衰变：decay谐波：harmonics，谐和：harmony基频：fundamental frequency固有（特征，本征）频率：natural (characteristic, eigen-) frequency简正频率（⽅式、模式）：normal frequency (mode)波节：node；波腹：antinode, loop⾳：tone；泛⾳：overtone；⾳调：pitch；⾳⾊：timbre声媒质及其性质媒质、介质：medium可压缩的：compressible；不可压缩的： incompressible压缩率，压缩系数：compressibility可相融的，不相融的：miscible，immiscible绝热的：adiabatic；等温的： isothermal体（剪切）弹性系数，体（切）弹性模量：bulk (shear) modulus热传导（率）：thermal conduction (conductivity)（容变）粘性：(bulk) viscousity（切变、容变）粘滞系数：viscous coefficient, coefficient of (shear, bulk) viscosity ⽆黏（流体）：inviscid (fluid)声速：sound speed频散：dispersion吸收（损失）：absorption (loss)；吸收系数：absorptivity, absorption coefficient 耗散（损失）：dissipation (loss)⾮均匀性：inhomogeneity多孔介质：porous media穿孔：peforation穿孔板：perforated plate穿孔⽐：ratio of perforation孔隙率：porosity声边界层（厚度）、趋肤深度：acoustic boundary layer (thickness)，skin depth 叠加原理波数声波及传播声波：sound waves, acoustic waves机械（⽔，重⼒，声重⼒）波：mechanical (water, gravity, acoustic-gravity) waves传播：propagation；纵（横）波：longitudinal (transverse) waves⾏（驻）波：traveling (standing) waves平⾯（柱⾯，球⾯）波：plane (spherical, cylindrical) waves表⾯（瑞利，漸失）波：surface (Rayleigh, evanescent) waves压缩（体）波：compressional (bulk) waves声压缩切变（弯曲）波：shear (flexural, bending) waves（切）应变：(shear) strain（切）应⼒：(shear) stress波导：duct, waveguide；声管：pipe, tube导波：guided waves相（群）速度：phase (group) velocity质点（体积）速度：particle (volume) velocity声压（级）：sound pressure (level)声强（级）：sound intensity (level)声功率（级）：sound power (level)响度（级）：loudness (level)响亮（度）：sonority分贝：decibel （dB）倍频程：octave声阻抗（阻，順，容，抗）：acoustic impedance (resistance, compliance, capacitance, reactance)；声质量：acoustic mass, acoustic inertance；声导纳（导，納）：acoustic admittance, mobility (conductance, susceptance)声阻（抗，阻抗）率：specific acoustic resistance (reactance, impedance)声特性阻抗：acoustic characteristic impedance；法向声阻抗率：specific normal acoustic impedance声导率：acoustical conductivity转移阻抗：transfer impedance阻抗匹配：impedance matching声传输线：acoustic transmission line波前，波阵⾯：wavefront正（斜，掠）⼊射：normal (oblique, grazing) incidence 反射（系数）：reflection (coefficient)透射（系数）：transmission (coefficient)传输损失，隔声量：transmission loss质量作⽤定律：mass law折射：refraction；衍射：diffraction；⼲涉：interference 回响、回声：echo衰減（系数）：attenuation (coefficient)驻波 standing wave⾏波 travelling wave声聚焦平⾯波球⾯波品质因数 qualityfactor涡旋：votex, 涡度：vorticity湍流：turbulence，层流：laminar flow绕射斯奈尔定律波⽮量全反射辐射，散射声源：sound source；源强：source strength点源：point source单极⼦：monopole；偶极⼦：dipole四极⼦：quadrupole活塞：piston像源：image source声场：sound field, acoustic field近（远）场：near (far) field声辐射（阻抗）：acoustic radiation (impedance)声发射：acoustic emission散射（截⾯，损失）：scattering (cross-section, loss)背向散射：backscattering互易性（原理）：reciprocity指向性：directivity传声器指向性直达声：direct sound回声：echo混响：reverberate（动词），reverberation（名词）⾮线性振动与声冲击波：shock waves声孤⽴波：acoustic solitary waves；声孤⼦：acoustic solitons声马赫数：acoustic Mach number分岔：bifurcation；混沌：chaos次谐波（共振）：subharmonics (resonance)声辐射压（⼒）：acoustic radiation pressure (force)声效应空化：cavitation声致发光：sonoluminescence声化学：sonochemistry声悬浮：acoustic levitation⽓泡共振：bubble resonance声材料与控制吸声材料（器）：sound absorbent (absorber)消声器：sound damper 声障：sound baffle, sound barrier隔声：sound insulation, soundproof隔声罩：acoustical enclosure声屏蔽：acoustic shielding隔声板：acoustic septum消声室：anechoic chamber消声器：muffler, silencer声扩散体：sound diffuser穿孔：perforation；穿孔板：perforated panel室内声学平均⾃由程换能，仪器设计，测量压电效应：piezoelectricity扬声器：louderspeaker；喇叭：horn 话筒，扩⾳器，麦克风：microphone。