噪声控制

As for the noise controlment in this design, except adopting low noise equipment technically, we will also build some noise controlling room in the main noisy area which can control the noise decibel under 70 dN, and can avoid harm for our workers.

本设计对噪声的控制除从工艺上采用低噪声设备外，还对车间的主要噪声区设置隔声操作室，将室内噪声控制在70dN以下，工人在室内操作可勉受强噪声的危害。

Based on a series of signal process and noise source identification techniques, especially the major noise source identification methods, such as expurgation method, sound intensity analysis, spectrum analysis vibro-acoustic correlation analysis and so on, the pass-by noise control of SC7080A and SC6360B are studied in detail. By the roadway and dais experiments, the major noise and radiating parts are identified and some economical controlling methods are made. For the SC7080A, to control the emissing noise from the intake and shell vibration of air cleaner, a intake muffler is installed between the air cleaner and intake valve. Based on the theory of Helmholtz resonator, One three-parallel-connected resonant silencer is designed and trial-manufactured. For the SC6360B, the attenuation performance of exhaust muffler in high frequency region is improved. To reduce the vibration noise of shell part, the structure of oil sump tank, exhaust manifold shield and exhaust manifold shield are analyzed and improved. At the same time, some measures, such as sound absorption, sound insulation, are taken to reduce the noise of engine surface emissivity and a sound shield is designed.

本文首先综述了目前国内外汽车加速噪声控制的现状、主要方法和技术措施，在此基础上，结合SC7080A和SC6350B汽车的车外加速噪声水平及现状，综合运用分别运行法、声强法、频谱分析法、声振相干函数法等现代噪声源识别方法，对SC7080A和SC6360B汽车进行了准确详细的车外加速噪声源识别并提出了经济可行的控制方案，针对SC7080A，主要在空气滤清器和进气阀门之间的进气管道上加装进气消声器，抑制空气滤清器壳体表面和进气口两处的噪声辐射，根据Helmholtz共振腔原理设计了三腔并联旁支型共振消声器，并进行了工程化设计和试制；针对SC6360B，主要改善了排气消声器在高频段的消声性能，对罩壳类零件进行了结构改进，降低了其表面噪声的辐射，并对发动机舱进行了吸声、隔声处理，设计了发动机隔声罩。

The methods for controlling transformer noise are introduced: for noise source control,using high-quality silicon-steel sheet,and adopting effective measures in transformer design,techniques and installation;for noise propagation control,adopting muffler device,sound insulation board and isolation booth,etc.to enhance noise attenuation.

详细介绍了变压器的噪声控制方法，在噪声源控制上选用优质高取向硅钢片，在设计、工艺和安装等诸多方面采取有效措施降低噪声；在噪声传播过程中采用缓冲装置、消声法、设置隔音层、隔音室等方法增大噪声在传播过程中的衰减以降低噪声。

In this thesis, some problems for controlling structural vibration noise using piezoelectric material are analyzed.

本文以控制结构振动噪声为研究对象，分析了利用压电材料进行不同结构的噪声控制问题。

Based on summarying the measures of traffic noise control in the world, in terms of theory and experience of noise control , as well as adapting concrete environmental condition and development tendency china western , this paper puts forward the measures of traffic noise control which reduct the effect of noise pollution and accelerat the management of highway environment protection .

在总结国内外防治交通噪声措施的基础上，根据噪声控制的理论经验，结合西部地区具体环境状况和发展趋势，提出了适合中国西部的交通噪声防治对策，以减少噪声污染和推动西部地区交通环保事业的发展。

The combustion noise control is an important aspect of internal combustion engine noise control.

燃烧噪声控制是内燃机振动与噪声控制领域的一个重要的研究方向。

The combustion noise control is an important aspect of internal combustion engine noise control.

摘要燃烧噪声控制是内燃机振动与噪声控制领域的一个重要的研究方向。

The classical feedforward active noise control methods with mean-square error criteria only consider second order statistics of signals, but neglect real existing non-Gaussian signals. Therefore, these methods do not perform well for non-Gaussian noises.

在前馈主动噪声控制中，基于均方误差准则的传统算法仅考虑了信号的2阶统计量，忽略了实际存在的非高斯信号，不能满足对非高斯噪声的控制要求。

Through the research on this project, a suit of applied technology and method of pass-by accelerating noise control of vehicle is built up, which also can be extended to noise control engineering in different cars.

通过本项目的研究，最终形成了一套实用的汽车车外噪声分析研究和控制的方法与技术，适合推广应用到其它相关车型的噪声控制工程实践中去。

The end linking the timing gears cap, the side wall of cylinder and the skirt section of the engineblock are the sound radiation resources of the two engineblock sides. Except that, this thesis calculates sound power level of radiated noise from the engineblock with MATV method. It is found that the noise radiated from the engineblock is slightly loud.

此外本文还应用MATV法计算了气缸体辐射噪声的声功率级，通过声功率级的计算发现：气缸体的辐射噪声偏高，达到了108.84dBA，并且在850Hz时，由于气缸体的激励频率与其第八阶固有频率相等，气缸体发生了共振，因而在该频率时，气缸体的辐射噪声最大，所占气缸体表面辐射噪声总能量比重也最高，该频率应该是本文噪声控制关心的重点。

They weren't aggressive, but I yelled and threw a rock in their direction to get them off the trail and away from me, just in case.

他们没有侵略性，但我大喊，并在他们的方向扔石头让他们过的线索，远离我，以防万一。

In slot 2 in your bag put wrapping paper, quantity does not matter in this case.

在你的书包里槽2把包装纸、数量无关紧要。