声学

The structure-acoustic coupled models of Santana2000 are built both with and without absorption material, and ANSYS finite element analysis software is used to calculate interior acoustic pressure due to panels vibration under specific frequency, then the acoustic contribution of panel is evaluated.

以桑塔那2000型轿车为实例建立无吸声材料和有吸声材料的结构-声学模型，使用ANSYS有限元分析软件计算车身板件在给定频率下振动引起的车内声压，进而求得板件的声学贡献。

Modal analysis of an acoustic system can determine its natural frequency and show the distribution of the acoustic quantities in space, give the knowledge about the way that the acoustic system responses are affected when changes are made in the excitation sources or in the domain geometry, and provide valuable information for the noise control of closed three-dimension domain.

通过对声学系统的模态分析，可以得到其固有频率以及在此频率下声学量在声场空间上的分布，了解到声源及声场空间几何参数的变化对声学系统的相应的影响，为三维封闭空间的噪声控制提供了依据。

RELIABILITY MTBF 600,000 hours Unrecoverable read errors 1 in 10^14 POWER Average idle current 5.0 watts Average seek power 7.30 watts Standby power 1.4 watts Sleep power 1.07 watts Maximum start current, DC 2.0 amps ENVIRONMENT Ambient Temperature Operating 0 to 60 degrees C Nonoperating -40 to 70 degrees C Maximum operating temperature change 20 degrees C per hour Maximum nonoperating temperature change 30 degrees C per hour Maximum operating case temperature 69 degrees C Relative Humidity Operating 5 to 90 Nonoperating 5 to 95 Maximum allowable humidity change 30 per hour Altitude Operating altitude -60.96 meters (-200 feet) Operating altitude 3,048 meters (10,000 feet) Nonoperating altitude -60.96 meters (-200 feet) Nonoperating altitude 12,192 meters (40,000 feet) Shock Operating vibration 0.50 Gs Operating Shock 63 Gs at 2 msec Nonoperating Shock 350 Gs at 2 msec Vibration Operating vibration 0.5 Gs at22-350 Hz Nonoperating vibration 5.0 Gs at 22-350 Hz ACOUSTICS Acoustics 2.6 bels Acoustics 2.7 bels

可靠性 平均无故障工作时间六十点○万小时不可恢复读错误1 10 ^ 14 电力平均闲置电流五点○瓦特平均寻求权力7.30瓦特待机功耗一点四瓦特睡眠电力1.07瓦特最大启动电流，直流二点〇安培环境常温经营0至60摄氏度非经营性-40 ℃至70摄氏度最大运行温度变化20摄氏度，每小时非经营性最大温度变化30摄氏度，每小时最大运行外壳温度69摄氏度相对湿度操作5至90 非经营性5日至95 最大允许湿度变化每小时30 高原高空作业-60.96米（-200米）操作高度三〇四八米（ 10000英尺）非经营性高度-60.96米（-200米）非经营性高度一二一九二米休克操作振动0.50亚基操作震动 63亚基在2毫秒非经营性休克 350亚基在2毫秒振动操作振动0.5气孔at22 - 350赫兹非经营性振动5.0亚基在22-350赫兹声学声学 2.6分贝声学仅有2.7分贝

The objective acoustical parameters and binaural room impulse response at different listening positions with different acoustical characteristics in classroom are obtained by using architectural acoustical simulation software ODEON.

应用建筑声学仿真软件ODEON仿真获取教室中具有不同声学特性的听音位置的客观声学参数和双耳房间脉冲响应。

The natural vocalizations of non-passerine(Columbia livia domesticus, Chicken), sub-oscinepasserine(Melopsittacus undulates. Psittacula Agapornis), Oscine passenon 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，亚鸣禽以及鸣禽为实验材料，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。

For the moment there is no acoustic design norm of shooting gallery inland yet.

介绍了杭州市25m靶场的声学设计，并分析靶场建成后的声学效果，最后就室内靶场的声学设计，提出了作者的一些看法。

The Pinyin model is Trigram that adds up same voice data in language model and it is a new link between original acoustic and language model.It can be used to obtain probability of interrelated Pinyin string.The results in experiments show that by using the model to make final process of the recognition of acoustic layer,the recognition rate of the top one can be increased 13 percent,and the rate of the front fine is similar with the...

拼音模型是累加语言模型中同音字的相关数据后得到的 3元模型，是在原来的声学模型和语言模型之间增加的一个新环节，可用来求取相关拼音串的先验概率，实验结果表明，用它作为声学层识别的后处理，可使第 1名的识别率提高 13个百分点，可使前 5名的识别率与原来声学模型输出前 10名的识别率相当

Then, the relation between vibration and sound, the acoustic holography method, the indeterminacy and identifiability of BSS, the BSS algorithm are discussed in detail. Based on above researches, the dissertation is divided in following four sections. The first section investigates the BSS algorithm suitable to acoustic feature separation. The algorithm of the joint approximate diagonalization of eigen-matrices is proposed. The spectra or the time-frequency distributions of source signals are the interesting features in ABD and they are separated from mixing signals by JADE algorithm. Then, the convolutive mixing model is transformed into a high-dimension instantaneous mixing model, and the deconvolution of source signals is achieved by the joint approximate block diagonalization of eigen-matrices. The proposed algorithm has a global minimum, and it is unsensitive to noise interference.

论文首先概述国内外声学诊断研究进展与盲分离研究进展，给出机器噪声声场与盲分离的数学描述，讨论了声振辐射、声全息、盲分离模型、盲分离可解性、盲分离结果不确定性、分离算法等基本问题，在此基础上，论文的研究工作分为以下四个部分：第一部分研究适用于声学特征分离的盲分离算法，提出基于特征提取的联合近似对角化盲分离算法，该算法以频谱特征或时频特征作为分离目标，从混合信号中分离源信号频谱特征或时频特征，最大限度地保留了与声学特征提取有关的频谱特征或时频特征，采用模型变换把卷积混合模型变换为一个高维瞬时混合模型，通过联合近似分块对角化算法实现源信号频谱特征与时频特征的盲反卷积。

The same position of the first plurality and the same position of the second plurality may be the only point on the first and second plurality of acoustic drivers joinable by a straight line.

所述多个第一声学驱动器的相同位置和所述多个第二声学驱动器的相同位置可以是所述多个第一和多个第二声学驱动器上的能被一条直线连接起来的唯一点。

Through the acoustical design of Nanjing Olympic sports center, it is found that many aspects of the existing code for acoustical design on gymnasiums deserve to be discussed, especially for large and overlarge gymnasiums.

国家体育场馆建设行业标准已对建筑声学指标做了明确规定，在对南京奥体中心体育馆进行声学设计时，发现现行体育馆声学标准还有值得商榷的地方，特别是对大型或特大型体育馆。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。