To study the acoustic unsteady combustion of srm , built the acoustic model of chamber . deduced the little amplitude sound wave 3d equation , used the finite volume discrete method to simulate . got the vibration model of three kinds of chamber 为研究固体火箭发动机声不稳定燃烧特性,建立了燃烧室内声学特性分析的物理数学模型,推导了小振幅声波三维波动方程,采用有限体积离散方法进行仿真,得到圆柱型、四片翼柱彤和五片翼柱型药柱三种燃烧室形状声学振动基本模态
Acoustic properties of space inside a railcar are analyzed based fem when frequencies are lower : 1 acoustic modal inside the railcar is calculated whether coupled or uncoupled with shell of railcar , 2 acoustic field inside the railcar is calculated when a force is given 针对某型铁路客车应用有限无法在较低的频率范围内对客车车内的声学特性进行了研究分析，得出了客车车内流体自身的模态和液体与车体耦合后车内流体的模态，并在给定激励下计算了客车车厢内部的声场。
This paper is based on the theory of environmental science , systematology and noise control engineering . noise control system and comprehensive harness of fan room have been researched . by the investigate , and measure of fan room noise . sound production principle , acoustics characteristic and the law of attenuation propagation have been analyzed . thus , the sound field model of fan roo has been put for put forward ward 本文以环境科学、系统科学和噪声控制学为理论基础，对风机房噪声控制系统及其综合治理进行研究，通过对风机房噪声污染调查监测，分析其发生机理、声学特性和传播过程衰减规律。
Psittacula agapornis ) , oscine passenon ( emberiza rutila ) and the vocalizations of sub - oscine passerine ( melopsittacus undulates , psittacula agapornis ) after sectioning nxiits were recorded by sharp gf - 6060 recorder . cooledit2000 , an acoustic analyzing software , was used to produce the original wave and it ' s expanded time windows , sonograms , spectrums and power static histograms . to distinguish the acoustic differences of their natural vocal and to find the changes of sub - oscine passerine ' s song after sectioning nxiits , the above results is acoustically analyzed and compared , expecting to provide some advantage to further explaining the mechanism of vocal production 本实验以非鸣禽(家鸽、家鸡) ，亚鸣禽(虎皮鹦鹉、牡丹鹦鹉)以及鸣禽(栗? )为实验材料，记录其正常叫声以及亚鸣禽断nxiits后的叫声，用cooledit2000声音处理软件制出原始信号及其展开图，声图，频率谱图以及能量统计分布图，并对所得结果进行声学比较分析，以期得到鸣禽、亚鸣禽及非鸣禽叫声在声学特性上的差异，以及亚鸣禽在断神经后叫声的声学变化，旨在为进一步解释其发声机制提供帮助。
In this paper , a study has been made of analyzing the acoustics and vibration characters of the plate & shell and stiffened plate & shell structures with fea ( finite element analysis ) and basic theories of structural vibration and acoustic radiation , which , to some extent , helps the nonprofessional people understand the acoustical characters of these structures through acoustical means 本文利用有限元方法，结合结构振动与声辐射基本原理，对板壳、加筋板壳结构的声?振特性进行了分析，利用信号处理技术实现结构声?振特性的可听化模拟。在一定程度上，使非专业人士也可以通过声学手段了解结构的声学特性。
With regard to some specific problems encountered in the process , the pointed answers are given by way of simulative experiments in laboratory . those problems are as follows : the relation between rt curve and rasti , different impacts caused by different acoustic characteristics on different standing waves , the changes of acoustic quality derived from different positions of sound absorption materials 而对此过程中遇到的某些特定问题，如：混响时间频率特性与清晰度的关系，不同声学特性对驻波的影响，吸声材料摆放位置不同带来的音质的变化等，则以在实验室模拟实验的研究方式予以针对性的回答。
The study instructs simulating valve leakage experiment , perfects valves leakage test technology and bases theoretically for applying valve leakage test in practice . the test stand is constructed and instrumented to accept a variety of valves in order to determine which characteristics of acoustic emission change with leakage rate . the data for each valve type is generated by varying valve type and working medium 建立模拟在用承压阀门内漏实验台，研究典型阀门内漏声源的声学特性，确定声发射特征参量与泄漏率的关系，为定量评价阀门泄漏率提供实验数据；通过对不同类型、不同规格、不同工作介质下的典型承压阀门内漏的实验研究，确定阀门内漏最佳检测区域，建立在用承压阀门内漏声学检测方法。
Based on apdl , the design language of finite element analysis software ansys , and visual c + + , the software on acoustics design of underwater cylindrical shell structure is developed . when input parameter of the cylindrical shell in the interface redeveloped in this paper , the software execute the batch file of apdl in the vc process to establish the finite element modal and carry out the analysis , the analysis result and the vibration mode can also be displayed . furthermore , the software has been developed to process the acoustics optimization design of the finite cylindrical shell with stiffener in appointed frequency range 本论文从便于工程实际应用出发，对使用有限元分析软件进行二次开发以方便结构振动分析及改进结构设计的方法和过程进行了研究，在此基础上对水下航行器圆柱壳体的结构声学特性进行了分析，在指定频率区间，对结构以振动辐射声功率级为目标函数进行了部分参数的结构优化设计，与此同时，为了方便有限元分析软件的使用和简化设计过程中大量重复的工作，利用ansys提供的参数化设计语言apdl ( ansysparametricdesignlanguage )结合vc对有限元软件ansys进行了二次开发，形成了一体化的水下圆柱壳体结构声学设计软件。
This dissertation is different from traditional speech enhancement methods which are based on noise characteristic such as adaptive noise cancellation or spectral subtraction processing . in this dissertation the speech signal conducted by bone was taken as the object to be studied and the exploitive study on the acoustical characteristic of speech signal conducted by bone was performed by the method of theory combined with experiment . then a proposition about speech reconstruction based on speech signal conducted by bone was presented , and the design of software and hardware was completed 本文与传统的基于噪声特性的自适应噪声抵消法、频谱减法等语音增强降噪技术不同，是以骨导语言为研究对象，采用理论与实验相结合的方法对骨导信号的声学特性进行了探索性研究，进而提出了基于骨导信号的语音重构技术，并完成了相应的软硬件开发。
