和声学

The tidal river discharge observing system of this thesis gives a new method and experience of the hydrology observing to the river reach and cross section with complicated landform and flow, or busy shipping. This system has achieved 3 innovations: instruments for measurements which use the unmechanized rotor and continue measuring ADCP as the velocity mainframe; methods of velocity measurement which change the vertical velocity measurement to horizontal velocity measurement; the tidal discharge measurement which solve the problem that current method of discharge measurement can not achieve the accuracy of the criterion according to the continuous real time observing over the velocity of flow.

本论文研究的感潮河流流量监测系统，具有测验设备的创新，用可连续测验的非机械转子式的声学多普勒流速剖面仪为测速主机；流速测验方式的创新，改变以往测取垂向流速为水平流速的方式；潮流量测验方式的创新，对流速进行连续实时的监测，解决了用现行测流方法达不到规范要求精度的问题；为地形、水流复杂或是航运频繁的测验河段和断面，提供水文监测的新方法、方式和经验。

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。

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。

This study deals with many branches of modern mechanics, such as structural dynamics, damage mechanics as well as coupling of multi-media and multi-fields. Therefore, the research on structural dynamic properties and underwater acoustic properties of intact and delaminated composite plate structures is not only of great theoretical importance but also of practical value.

舰艇声纳导流罩的动力特性和声特性结构上涉及到复合材料结构动力学、损伤力学以及多介质、多场耦合力系等近代力学分支，因此，健康和分层损伤复合材料层合板结构动力特性和水中声学特性研究的课题，既有重要的理论研究的意义，也具有实际工程价值。

The chrome plated parts and metallic hairlines add updated interest while their highly advanced acoustic systems and diaphragm guards produce a high-fidelity lifelike sound.

镀铬的部件和金属耳机线使其更具吸引力，而且其非常先进的声学系统和振动膜保护套能够产生逼真的Hi-Fi效果。

The study of sound is of importance not only in music and speech but also in communications and industry.

声学研究不仅在音乐和语言方面很重要；而且在通信和工业方面也很重要。

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。

Simulation results show that the method solves dynamical product of HRTF data based on moving sound sources and the smooth transition of the fore-and-aft sound sequence signals. The method is more reliable and accurate than other methods, and realizes indoor acoustic simulation based on dynamic mechanism.

仿真结果表明，该方法较好地解决了运动声源HRTF数据的动态产生和前后声信号段平滑过渡问题，具有更好的真实性和精确度，实现了基于动态机制的室内声学仿真方法。

Simulation results show that the method solves dynamical product of HRTF data based on moving sound sources and the smooth transition of the fore-and-aft sound sequence signals.

仿真结果表明，该方法较好地解决了运动声源HRTF数据的动态产生和前后声信号段平滑过渡问题，具有更好的真实性和精确度，实现了基于动态机制的室内声学仿真方法。

A pop-science writer who has made Einstein, acoustics and meteorology intelligible to the right-brained, Levenson transforms inflation and metallurgy into a suspenseful detective story bolstered by an eloquent summary of Newtonian physics and stomach-turning descriptions of prison life in the Tower of London.

一个弹出科学作家谁已成为一个悬疑侦探由牛顿物理学和胃转折点，塔监狱生活的描述有力地带动摘要爱因斯坦的故事，声学，气象学理解的右脑，李文森变换通货膨胀和冶金伦敦。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。