声学的

Spectral element methods for partial differencial equation is introduced in this study from viewpoint of the collocation approximation of Chebyshev polynomial. Wave Equation and its space discretization are deduced. Two time integral methods, central difference method and implicit Newmark method, are introduced, and their stability and applicability are also discussed in some details. The significance of absorbing boundary conditions in spectral element methods for Aeroacoustics is explained, and Clayton-Engquist-Majda absorbing boundary conditions is emphasized and introduced, then the discrete scheme of this boundary conditions is deduced and applied to spectral element methods for wave equation.

本文从Chebyshev多项式逼近理论出发，详细介绍了谱元方法求解偏微分方程的过程；推导了流体中的声波动方程并在空间上对其进行了谱元离散；详细讨论了两种时间积分方法──中心差分法和Newmark方法，分析了它们的稳定性条件，并从理论上对比了两种方法的优缺点和适用范围；将吸收边界条件推广应用于谱元方法求解气动声学问题中，重点介绍了Clayton-Engquist-Majda吸收边界条件的原理和公式，推导了该吸收边界条件的变分形式，并将其引入波动方程的离散形式中。

On the base of the acoustics , a whole linear time - varying discrete speech produce model is established through anatomising the factors including track , driving source and lip eradiation the mechanism of speech in this paper , and we draw a conclusion that the time between glottal closure is pitch period

本文从声学理论出发，剖析了语音产生的机理，综合考虑声道、激励源和嘴唇辐射三方面的因素，建立了一个完整的、线性的和时变的语音产生的离散系统模型，得出两次声门闭合事件之间的时间间隔就是基音周期的结论。

It gives up the unreasonable spherical hypothesis which is out of accord with the reality.

考察了不同壁面、空泡离壁面的距离和空泡的气体含量对空泡演化及辐射噪声的影响，该方法将边界元方法得到的空泡演化情况与声学方程在特殊情况下的解结合起来，放弃理论分析上不合理的球形假设，并考虑了边界的影响，这样更符合实际的空化现象，得到了与实验相一致的结论。

The biggest change from the well established ES-335 to the thinline 330 was the absence of the wooden center block that enabled a deep, full sound from the guitar that was more commonly associated with the bigger bodied acoustic/electric models.

最大的变化来自完善的第ES - 335的thinline 330是没有的木制中心区块，使深刻的，全面的吉他声音更普遍的是与健全的更大的声学/电动模型。

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。

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。

But experiments show that not all the intensity of the neutral tone get weaker, just the energe of the neutral tone word s last part gets weaker than the ordinary word. Experiments also show, it is the voice-pitch and voice-length that make the neutral tone syllable indistinct.

关于轻声的声学性质，我们往往认为轻声是音强特别弱，有关实验结果表明，轻声的音强并不是全都减弱，但轻声词后字的能量毫无例外地都比普通&中重&格式的词的后字的能量减弱。

Firstly,the inputs of the lyrics are converted into speech with the text to speech synthesis system.Then,the melody parameters of the song are extracted from the MIDI file.At last,the melody control model is adopted to achieve the lyrics to song conversion by modifying the acoustic parameters of speech signal.

首先利用一个文语转换系统将输入的歌词转换为语音，同时从歌曲的MIDI文件中提取歌曲的旋律参数，最后通过旋律控制模型对语音信号的声学特征进行修改，实现由歌词到歌曲的转换。

Fluidization and Sounding Pressure Characters Experimental Research on Pulsating Fluidized Bed After verifying experimentally the Rijke type self-exciting pulsating fluidized bed combustion, under different operating conditions (different empty cross-section wind speed and inaction bed height), experimental research the oscillation characters of sounding pressure in the pulsating fluidized bed. The results indicate that the sound characters in the Rijke type self-exciting pulsating fluidized bed combustor are the same with it in the Rijke type combustor, the pressure in the combustor oscillate up and down in the sinusoidal manner and the pressure is the superposition of the multiple harmonic waves.

脉动流化床流化与声学压力特性实验研究在实验验证了Rijke型自激脉动流化燃烧概念后，在不同运行条件(空截面风速、静止床层高度)下，实验研究了Rijke型自激式脉动流化床的声压振动特性，研究结果表明：脉动流化床内建立起的声波特性和Rijke型脉动燃烧器内的一样，各点压力呈正弦规律上下振动，且压力是基波幅值最大的多次谐波的叠加。

An equation is derived by theoretical analysis, to establish a relationship between suspended sediment concentrations and ADCP echo intensity output. For the survey at the entrance to Jiaozhou Bay, an ADCP is mounted on a moving vessel; the calibration coefficient in the equation is determined by in situ measurement. Then, a semi-empirical formula is obtained and used to calculate suspended sediment concentration profiles along several crosssections.

理论分析获得了海水中悬沙浓度与ADCP输出的回声强度之间的函数关系式；在胶州湾口门进行走航式测量，同步采水样进行现场校正来率定相应的ADCP声学信号，获得了计算悬沙浓度的半经验公式；进而得到走航断面准同步的悬沙浓度剖面。

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。