Posterior acoustic attenuation 82 cases.
衰减82例。
Meanwhile, the existence of the acoustic attenuation coefficient benefits the axial resolution.
同时，声衰减系数的存在有利于轴向分辨率的提高。
Two new medium parameters related to acoustic attenuation are introduced and an acoustic propagation coefficient is defined.
本文引入两个与声衰减有关的介质参量，定义了声传播系数；
The advantages and shortcomings of the three methods for the prediction of silencer acoustic attenuation performance are discussed.
通过算例分析和总结三种方法预测消声器声学性能的优缺点。
The acoustic attenuation of suspending liquid is divided three kinds as absorption attenuation and scattering attenuation and diffusion attenuation.
悬浮液的声衰减分为三种主要类型：吸收衰减、散射衰减和扩散衰减。
The 3-d numerical methods are used to predict the acoustic attenuation performance and flow resistance characteristics of internal combustion engine exhaust silencers.
使用三维数值计算方法预测内燃机排气消声器的声学性能和阻力特性。
Therefore, the present thesis will investigate in detail the calculation methods of acoustic attenuation performance of silencers and the acoustic characteristics of perforated elements.
本文针对消声器声学性能的计算方法和穿孔元件的声学特性开展系统研究。
Methods The color and transparency of different concentration phantoms were observed. Properties including density, acoustic speed and acoustic attenuation of PAA gel phantom were measured.
方法观察模块浓度的不同所致颜色与透明度的变化，并对PAA模块的声学特性包括密度、声速及声衰减进行测量。
Expresss the factors resulting in the attenuation of acoustic waves.
请陈述导致超音波衰减的各项因素。
After built the material's defect model in theory, combined the attenuation image and damage mechanics of acoustic, we can get the material's invalidation model.
从理论上建立材料的缺陷模型，并结合声衰减分布图与超声损伤力学原理，就能获得材料的失效模型。
The existence of various lacunas in bolt bonding system will cause the acoustic wave energy attenuation, phase aberration and frequency dispersion.
由于锚固体系中有不同大小和程度的缺陷，声波在传播过程中将产生能量衰减、相位突变及频散现象。
An acoustic log that USES the attenuation of compressional and shear waves to locate fractures.
利用纵波和横波的衰减确定裂缝位置的一种声波测井方法。
Conclusion Liver tissues and structures varied by HL-1 quick intravenous infusion. The promotion in ultrasound attenuation and absorption indicated a shift of acoustic environment.
结论静脉快速输入HL - 1可使兔肝脏组织结构发生相应的变化，使肝脏声吸收衰减增加，因而改变了肝脏组织声学环境。
The rock acoustic parameters in this paper include wave amplitude, spectral amplitude, spectral area, spectral density, wave velocity and attenuation coefficient etc.
这些岩石声学参数为波幅、谱幅、谱面积、谱密度、波速度、衰减系数等。
A wireline well log of the sonic type that locates fractures in the rocks adjacent to the wellbore by the attenuation of acoustic energy across the fracture.
属于声波类型的一种测井方法。根据穿过裂缝的声波能量衰减来确定井眼附近岩石中裂缝的位置。
The acoustic character controlled by the active noise attenuation system in ducts has been analyzed in detail on premise of semi-infinite ducts.
在假设半无限长管道的前提下，详细分析了噪声有源控制系统作用下的管道声场特性。
Express the factors resulting in the attenuation of acoustic waves.
叙述引起音波衰减的因素。
The velocity and attenuation coefficient were measured in the under water acoustic laboratory.
在水声实验室进行原位测量实验，得到了声速和声衰减的数据。
It is shown that the attenuation coefficient will decrease obviously with the increase of Mach number, and the nonlinear acoustic resistance and acoustic mass will reduce slightly.
研究表明，随着气流马赫数的增加，吸声结构的消声系数明显下降，微穿孔板的非线性声阻和声质量修正值都略有减少。更需注意，在高速流条件下吸声结构的共振峰将会发生偏移。
The quality factor Q of the acoustic wave attenuation is a comprehensive parameter reflecting the integrality degree of rock mass.
岩体声波衰减品质因素Q值是反映岩体完整性程度的综合参数。寻找稳定、可靠、简便的计算方法是将Q值应用于现场测试的关键。
The quality factor Q of the acoustic wave attenuation is a comprehensive parameter reflecting the integrality degree of rock mass.
岩体声波衰减品质因素Q值是反映岩体完整性程度的综合参数。寻找稳定、可靠、简便的计算方法是将Q值应用于现场测试的关键。
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