声学

According to the acoustic model of piston slap noise, how the parameters affect the piston slap noise at different rotate speed was discussed. And those parameters were piston clearance, piston pin offset, connect rod ratio, piston skirt stiffness, crank shaft offset, height of piston's gravity center, total length of piston skirt, vertical position of piston-pin axis and under part length of piston skirt.

借助建立的活塞拍击噪声理论声学模型，深入探讨了配缸间隙、活塞销偏移量、连杆比、活塞裙部刚度、曲轴轴线偏移量、活塞质心高度、活塞裙部总长度、活塞销轴线竖直方向位置和活塞裙部下段长度等主要影响参数在不同的转速下对活塞拍击噪声的影响规律，初步总结出活塞低拍击噪声设计和改进的基本规律。

The plan which they approved calls for the installation of meteorological buoys with acoustic doppler current profilers and coastal sea level measurement systems on the eastern and western sides of the Yucatan Channel.

他们计划通过呼唤安装与气象浮标及声学多普勒海流剖面沿海一级计量体系的东西方的尤卡坦海峡。

Compact pentroof combustion chambers and high-strength pistons that are resin-coated to reduce friction, low-tension piston rings and a low-friction valve train that uses roller rocker arms also are important features of this engine, as is an Acoustic Control Induction System that changes the length of the intake manifold runners based on engine speed and throttle opening.

紧凑pentroof燃烧室和高强度的活塞是树脂涂层以减少摩擦，低张力活塞环和低摩擦气门，使用滚子摇臂也是这个引擎的重要特色，是一种声学控制感应系统这改变了进气长度发动机转速和节气门开度为基础的多方面的选手。

Known for the innovation, performance and silent acoustics, Noctua has grabbed the hearts of many enthusiasts.

对创新，业绩和沉默声学已知，猫头鹰已经抢走了许多爱好者的心。

The usual configurations of acoustic cavities are as Helmholtz resonators, or quarter-wave slots.

通常配置的声学腔作为赫姆霍兹共振器，或四分之一波插槽。

It turns out that the flow and noise characteristics are quite complex and different from those of incompressible jets due to existence of quasi-periodic shock cell structures.

超声速射流是一般工业和军事工业中得到广泛应用的重要流动现象，对其流动特性和声学特性的研究，在实际应用和学术研究上有重要的理论价值和实际意义。

Flexible passive isolators are located between the rigid body and the raft, and between the raft and the flexible base.

在此基础上，分别推导了带有粘弹性材料的筏架结构和艇体与声学介质耦合的动力学运动方程式。

The principle and implementation of some familiar reconstructing algorithms on complex temperature field by acoustic methods is also presented. In order to improve the stability of the solution, the regularization method can be used to convert an ill-posed problem into a well-posed problem.

此外，还介绍了复杂温度场声学测量重建的几种常用算法的原理及实现方法，为了提高解的稳定性，可使用正则化方法将不适定性问题转化为适定性问题。

By means of the present model certain phenomena related to the nonlinear acoustic properties of an orifice, such as the roll-up of the shed vortex sheet and the forming of the Vena-Contracta are simulated. For a sinusoidal sound pressure, the time- history of the average velocity through the orifice is computed, and the nonlinear distortion of the velocity is examined by means of the Fourier decomposition.

依据此模型，对圆孔声学非线性效应的若干特征现象进行了数值模拟，如脱落涡层的卷曲，Vena收缩段的动态形成；在孔板前声压按余弦规律变化的情况下，计算了孔中平均速度的时间历程，并借助于Fourier分解分析了孔中平均速度的畸变情况。

Objective To study the acoustic characteristics of vowel sonogram in normal adults and patients with benign vocal fold lesions and explore it's effect on diagnosis and treatment of benign vocal fold lesions.

目的 研究正常人及声带良性增生性疾病患者元音语图声学特征，探讨该测试方法在声带良性增生疾病的诊断及治疗中的应用价值。

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。