查询词典 sound frequency

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。

On the aspect of error compensation, the system using the geometric average sound pressure instead of the arithmetic average sound pressure to get the sound pressure of the measurement point. This method not only reduces the high frequency error in the sound intensity measurement, which compensates the finite difference approximation error, but also greatly reduces the computation of the sound pressure spectrum.

误差补偿方面，课题采用几何平均声压代替通常的算术平均声压来计算双传声器法的声场声压值，这样不仅可以有效的减少声强测量中的高频误差，对有限差分误差起到了补偿作用，而且还大大减小了声压谱计算中的计算量。

Fiber layer ply increases, resonance absorbs frequency to increase to unit weight of; of shift of low frequency direction, sound power absorption coefficient increases in the begining more apparent, subsequently rate of hole of; of amplitude hasten delay increases, hempen fiber sound power absorption coefficient increases gradually.

纤维层厚度增加，共振吸收频率向低频方向移动；容重增加，吸声系数开始时增加比较明显，随后增幅趋缓；孔隙率增加，大麻纤维吸声系数逐渐增大。

Using 75 varied low frequency noise samples with adjusted-loudness as sound stimuli, we investigate sound quality for low frequency noise with paired comparison method.

以等响处理后的 75 个稳态低频噪声样本为例，采用成对比较法，设计并完成了有 24 位评价者参与的大规模实验室主观评价实验。

In this paper it is believed that the onset process is from the unorderly sound waves generated by heated gases, through ordering the sound waves, regenerator onset in a high natural frequency, followed by steady oscillation whose frequency is controlled by resonance tube.

本文认为热声热机的起振过程是从气体被加热产生杂乱的声波开始，经过声波的规则化先从回热器的高频率自激振荡振动，继而扩展到以谐振管内气体固有频率为主导的整个系统的稳态起振。

It can measure peak particle, peak displacement, peak particle acceleration, frequency at the peak velocity and the resultant peak partide velocity, peak sound , and frequency at the peak sound in three dimensions.

NCSC 5300是便携式固化计算机控制的测震仪，可以调出测点的三维振动速度、振动加速度、质点振动位移、振动频率和噪声强度、噪声频率，打印出测试结果及振动频率与三维振动速度的关系图、三维振动波形图，是理想的爆破测震仪器

By Using CPB to analyze the sound insulation character, it show that when the cavity depth is 30mm, the sympathetic vibration exist around the centre frequency of 200Hz of the system, the frequency character contours of sound insulation represent a lowest value. While the cavity depth is 40mm

使用CPB分析材料组合系统的隔声特性，当空腔深度为30mm，系统在中心频率200Hz附近产生共振，隔声频率特性曲线在该位置形成一个低谷；当空腔深度为40mm，隔声频率特性曲线在中心频率为160Hz位置形成一个低谷。

The agglomerations sizes of fine particles in the fluidized bed are smaller under higher SPL. The sound waves have little effect on the agglomerations when it is under 120dB. But the agglomerations sizes will be dramatically reduced to 180μm from 720μm when the SPL is above 130dB. The umf has a minimum value at an appropriate frequency of sound and a good quality of fluidization can exist in a greater ranges of frequency of sound when the SPL is higher.

当频率高于120Hz，流化床中形成聚团尺寸随着频率的增加而增大，最小流化速度也随着频率的增加而增大，当频率低于120Hz，流化床中形成聚团尺寸随着频率的减小而增大，最小流化速度也随着频率的减小而增大；料层越高，声波的衰减越大，超细颗粒的流化效果越差，最小流化速度越大。

Connaughton (1994) and Sprague (2000) mentioned that the differences of length, weight, and tension of the sonic muscle and the amount of protein and glycogen affect the types of sounds emitted. To reveal the producer of high-frequency sound, this research analyzed and compared the length, width, thickness and somatic of sonic muscle and the amount of protein and glycogen in seven sciaenid species occuring on the west coast of Taiwan (Johnius tingi, Johnius sina, Johnius amblycephalus, Johnius amblycephalus, Pennahia argentata, Chrysochir aureus, and Otolithes ruber), then to find if the differences of physic parameter and energy supplication are the major factors making O. ruber produce high frequency of sound.

在Connaughton (1994)和Sprague (2000)研究报中指出造成石首鱼产生不同型态的声音主要取决於发声肌肌纤维的长度、重量、张力、蛋白质与肝醣含量的差异性，为了证实高频声音确实为红牙鱼或所产生，本研究将分析比较在台湾西岸海域其他不同石首鱼(红牙鱼或、黄金鳍鱼或、白姑鱼、中华叫姑鱼、皮氏叫姑鱼、丁氏叫姑鱼与顿头叫姑鱼)发声肌之长度、重量、蛋白质与肝醣含量差异，探讨发声肌在物理参数与能量的供应的差异是否为造成红牙鱼或产生高频鸣音之主要因素。

Pitch frequency by the sound level of the object decision, high frequency sound on the high, low frequency sound is low, the existing international standard pitch was in May 1939 in London by the International Standards Association of a1 = 440 Hz.

音高是由发音物体振动频率的高低决定的，频率高声音就高，频率低声音就低，现行的国际标准音高为1939年5月国际标准协会在伦敦通过的a1＝440赫兹。

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。