声学上

At the same time, the resonant frequencies of four kinds of resonator are calculated by the programs which are made with Matlab software. The effect of resonator geometrical parameters on resonant frequency is theoretically analyzed. In order to carry out the acoustic and aerodynamics performances tests, seven resonators are designed and made, and a specialized engine intake silencer and exhaust silencers test bench was designed. The tests and analysis are performed as well.

在此基础上设计并加工了两类七个共振型进气消声器，研制了发动机进排气消声器性能测试实验台，开发了发动机进排气消声器声学性能测试软件，并在该实验台上测试了所设计的进气消声器静态工况下的传声损失，从实验的角度研究了共振腔的尺寸、形状对其共振频率的影响及其趋势。

A seismic scattering tomography method based both on the above-mentioned results and the fixed point inversion that is a sort of global optimization method is developed.

在地震波传播及散射理论研究中，我们推出了任意非均匀声学介质中的格林函数，并在此基础上给

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 finite element models of an engine block, oil pan, valve cover and gear cover were established by using the ANSYS software, and the calculation results were validated by the test results.

无论采用何种燃油供给系统和燃烧方式，都有必要对柴油机表面的振动特性和声学特性规律进行研究，在噪声向外传递的途径上最大限度地控制噪声水平。

Equivalent stretch elastic modulus E,sound reflection R and transmission coefficient T are calculated by the method of equivalent stiffness and transfer matrix separately.

通过试验获取了碳纤维、凯夫拉纤维、玻璃纤维、超高分子量聚乙烯纤维复合材料的力学性能和声学性能参数，在此基础上分别利用等效刚度法和传递矩阵法，对CF/UHMPEF、CF/KF、CF/GF混杂纤维复合材料的拉伸刚度、声反射系数和声透射系数进行计算。

The result? Smiles all round from the owners - well, they're still not too happy with the looming presence of the elevated speakers, but we'll sort that some time - and at last some imaging and sense of reality. Enough to work on when they try biwire cables in place of the single-wire stuff they're using.

后来我们用一些东西将音箱向上垫高了20cm，这样使比较低的高音单元发出的声音被沙发很好的吸收，然后我们用毛巾掩住了壁炉口直到后来我们用声学泡沫进行了替换达到了较好效果，并且我们也在音箱上安装了防止震动的脚钉。

Aiming at realizing processing long and thin hole on the vitro ceram, the ultrasonic machining technique was used. The design of ultrasonic machining acoustics system was completed. The analysis of the tool distorted and stress under the different pressure force was taken by finite element analysis.

为实现在微晶玻璃上的细深孔加工，采用了超声加工方法，完成了超声加工声学系统的设计，并用有限元分析方法对工具在不同压力下的变形和应力进行了分析。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。