声学

Compared with the Upwind Scheme results and the theoretical values, it is showed that the LDFV scheme has the property of low dispersion and is suitable for aeroacoustic problem computation.

分别给出了远场和固壁的适用于气动声学计算的边界条件处理原则。

They found M a ry, as usu a l, deep in the study of thorough- base .

她们发觉玛丽还像以往一样，在埋头研究和声学。

Professor Jorge Arenas of the Institute of Acoustics in Valdivia, Chile, acknowledged that the problem was serious but said,"NASA has developed one of the safest and risk-controlled space programs in engineering history."

智利的valdivia大学声学系 Jorge Arenas 教授知道这是个严重的问题，但是说："美国国家宇航局已经开发出一个被认为是工程历史上其中一个最安全的空间风险监测系统"

A method to calculate the volume of a computer model by vector analysis is introduced.

用向量几何的分析方法，推导了计算机声学仿真模型体积的计算方法。

In DHMM-based speech recognition, vector quantization permits the measure to phonetic similarity among speech representations to be shared if the acoustic distance among them is below some given threshold.

在基于DHMM语音识别中，若语音帧声学特征间的距离测度在给定的范围内，矢量量化为这些语音帧共享相同的语音学相似测度提供了可能。

This paper concerns with the study of the acoustic characteristics on velar stops.In Standard Chinese,Chinese dialects and many other languages,there is a great difference between velar stops and bilabials,alveolars in VOT, silence ,burst,and so on.

通过对汉语普通话、方言和其他几种语言中塞音①的声学特征进行考察，发现其中的舌根塞音/k/、/k' /在成阻、持阻和除阻爆破几方面均具有一些与双唇塞音、舌尖塞音不同的表现，并进行了初步的探讨与总结。

In this paper, the new idea simultaneously using the Planar Laser Induced Fluorescence technique and the Acoustic Doppler Velocimeter technique is applied to research the coherent structure of turbulent boundary layer.

本文在评述紊流边界层拟序结构研究现状的基础上，受前人研究工作的启发，提出了使用平面激光诱导荧光技术与声学多普勒测速技术相结合的方法同步观测和研究紊流边界层拟序结构的新思路。

The scattering intensity and the sound velocity of the acoustic phonon decrease with x.

实验还发现声学声子的散射强度和声速随Bi含量的增加而减少。

The phylogeny and applied prospect of MES are summarized in the paper. The principle of this system is analyzed from the point of view of acoustics. The surveying and filtering technology of auxiliary parameters, sounding data and the theory of image form, backscatter strength data processing, are researched deeply in the paper. The optimal model of velocity of sound is given. For sound ray tracing, some methods of correction of sound ray curve are developed. At the same time, an ideal model of sound ray tracing is proved and given. The GPS technology is applied for the determination of tide, attitude of vessel. Moreover, some methods are given. As an important topic, the systematic error is discussed in the paper. Some filtering methods are researched in this paper. Based on the current methods of image processing, the procedure and methods are tested and given that adapt to sonar image processing.

本文研究的工作是在总结多波束声纳测深系统的发展历史、应用前景的基础上，从声学角度分析了多波束系统的工作原理；对多波束辅助参数的测定和滤波方法、测深数据的滤波方法、多波束声纳图像的形成机理、图像处理以及最终应用等作了比较深入的研究；得出了适合于多波束精密深度计算的最优声速模型和声线改正模型；提出了 GPS 载波相位定位技术用于多波束辅助参数测量的思想、算法，改善了多波束系统的作业模式；系统地分析了深度数据的误差来源和类型，首次将系统误差作为影响测深精度的主要因素给以研究，并给出了削弱系统误差的方法，提高了深度数据的质量；对多波束声纳图像的形成、处理方法进行了细致的研究，给出了适合多波束图像处理的算法和流程，并从理论和实践上对声纳图像的应用进行了比较全面的研究。

In this study we combined two-dimensional, Doppler, three- and four-dimensional echocardiography, Transesophageal echocardiography , and the new technique-acoustic quantification with radionuclide ventriculography and right heart catheter examinations a...

本研究利用经胸二维超声、多普勒超声、三维及四维超声、声学定量技术和经食管超声等多种超声技术，与核素心室造影、结合较为系统地对右心功能进行了研究。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。