声学

To evaluate the value of urethral retrograde contrast sonography in the diagnosis of urethral diseases.

目的：探讨逆行尿道声学造影在尿道疾病方面的诊断价值。

Objective:To evaluate the clinical value of ultrasonohysterography in diagnosis of uterine diseases.

目的：评价子宫声学造影在诊断子宫疾病中的临床价值。

Methods: Proceed hysterosalpingography and patency test using acoustic contrast agents in stead of iodipin and observe the uterotubal ultrasonographic images under the conditions of transvaginal sonography and CDPI.50 infertility women were observes by transvaginal sonography,Ultrasongraphic hysterosalpingographyand color Doppler imaging,analyses the character of dynamic ultrasound images.

利用超声声学造影剂代替碘油行子宫输卵管造影及通液术，并在实时阴道超声及CDPI状态下，观察子宫输卵管动态超声图像特征。

Golikov as the general and single-valued criterion for evaluating the acoustics of rooms and auditori- ums have been critically examined,with detailed discussionsconcerning:(1) the empirical foundation of the articulation-Q"functional relationship A= f,(2)the derivation of the"particular criterion"or the optimum re- verberation condition form Q",(3)the meaning of a time integration of the "noise-interference factoras viewed from the theorey of auditory perce- ption...

主要内容有：(1)以在不同的条件(如语言、测试人员、宣读方式以及声学场所等)之下的清晰度测验结果来验证 A=f函数的适用性，(2)判断了从Q&来推求以体积为参数的最佳混响时间的可能性，(3)，从听觉理论来讨论&混响干扰因子&对时间积分的意义，(4)讨论了原作者对&噪声因子&的看法，指出了&噪声因子&定义中的一些值得存疑之处。

In this paper, the research has been given on the double weldable ceramic cutting tool by means of the acoustic microscope .

利用声学显微镜对双层可焊接陶瓷刀具材料进行研究，对双层材料界面及影响材料品质一致性的因素进行了分析，发现了两种材料在界面结合处分布不均匀及成块状分布等现象，并提出了改进材料设计的思路。

In simulation wells, acoustic sonde designed under this idea could detect and record reflection signal from interface 7~10m away from borehole surface.

在模拟井中按上述思路组装的声系可以测量记录到距离井壁约7~10m处声学界面的反射波信号。

This technology, developed by Holosonics , has introduced a directional speaker unit that many retail chains are currently testing for use in their stores.

这项由全方位应用声学公司开发的技术，引入一个导向扩音器单元，许多零售连锁店目前在店里试用。

After the analysis of the algorithms model of MPEG-2 AAC, the thesis optimizes some blocks with great computation of Psychoacoustic Model, Filter banks and Quantization coding, etc. It omits some function blocks which have much computation and avail little to the gain of coding, for example, prediction in time domain, TNS, etc. It also adopts some fast algorithms to reconstruct some model for the reason of real time characteristic.

在对 MPEG-2 AAC算法模型进行分析之后，对心理声学模型，滤波器组和量化编码模块等计算量较大的模块进行优化，同时也省略了部分运算量大但对编码效果增益不明显的几个模块，如时域预测和 TNS 等，并使用了一些快速计算技术对算法模型进行实时化改造。

True to tradition, these musicians use only acoustic instruments.

真正的传统，这些音乐家只用声学仪器。

Through a great number of objective analysis for sound characteristics and subjective audition experiments, new sound quality parameters used in mechanical and electronical products are proposed.Firstly, the source characteristics of cars and air-conditions are analyzed.

首先，本文明确了声质量的定义、摸清了研究现状，指出仅以A声级进行声质量客观评价的局限性，在分析汽车和空调噪声的声源特性后，确定以A声级结合响度、尖锐度和波动强度三个心理声学指标来作为机电产品声质量客观评价的基础参数。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。