查询词典 hum noise

Noise can be reduced by about 2 dB by using oil-resistant rubber isolator to reduce solid-borne sound transmission; the setting-up of semienclosed noise barriers can not only reduce the work region's noise of workshop by 13 dB, but also adapt to the gas's characteristic involved with H2S, CO, and other poisonous components without supplied mandatory ventilation; locating the noise absorbers on the walls and ceiling of workshop can reduce noise by 8 dB; the exhaust silencer's elimination volume can reach above 30 dB which is designed in accordance with the exhaust noise spectrum characteristic of gas-combustion generator. By the combination of these measures, the noise of the gas- combustion generator will be under effective control, so that the gas power plant's noise pollution problems can be resolved.

通过选用耐油性好的橡胶隔振器减少固体传声，可降低噪声约2 dB；设置半封闭式机组隔声屏障可降低生产车间工作区域内的噪声达13 dB，并且适合瓦斯发电气源中含有H2S、CO等有毒有害气体的特点，不需增加强制通风措施；在生产车间四周墙壁和顶棚上敷设吸声体，最大可降低空间噪声8 dB；根据瓦斯发电机排烟噪声频谱特性设计的阻抗复合式消音器的消音量可以达到30 dB以上。

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 module of Zone Abnormal noise Processing ofOMEGA sps is an effective mothod of suppressing noise in Shot gather and CMPgather.②The noise of alternating current is suppressed by notching filter in theseismic data which dominating frequency is far from 50Hz.Otherwise,it issuppressed by mono-frequency noise suppression in the time domain of CGGsps;③The module of F-X Coherent Noise Suppression of OMEGA sps isa good mothod to suppress coherent noise.

此方法在炮域和 CMP 道集上应用效果最好；②对于工业干扰，原始资料主频远离 50Hz 时，采用陷波的方法较为简便，否则采用CGG 系统中的时间域单频压制方法；③对于相干噪音压制，OMEGA 中的频率-空间域相干噪音压制方法在知道斜干扰视速度的情况下，应用效果明显。

For the problem that the suppression of co-channel interference and suppression of noise can't be balanced in signal-to-jamming and noise ratio maximization method for the linear precoding of multiuser multiple-input multiple-output downlink systems, an improved scheme that the term of noise variance is modified as a piecewise linear function is proposed, in which the balance between suppression of co-channel interference and suppression of noise can still be maintained even when the noise variance is a small value through piecewise modifying the term of noise variance, and thus the bit error rate and capacity of the systems are further improved.

针对多用户多输入多输出系统下行链路线性预编码的信干噪比最大化方法中，共信道干扰抑制和噪声抑制不能有效平衡的问题，提出将其中的噪声方差项修正为以噪声方差为变量的分段线性函数的改进方案。该方案通过对噪声方差项的分段修正，在噪声方差的值较小时依然能够保持共信道干扰抑制和噪声抑制间的平衡，从而使系统的误比特率性能和容量得到进一步提高。

Circuit noise within the system: such as CRT deflection circuit power to the secondary emission of noise _ mother _ Sina fashion blog, fashion, mom, wedding photography network to provide in accordance with the relationship between noise and signal, image noise can be divided into additive and multiplicative noise two types of noise ...

系统内部电路噪声：如CRT的偏转电路二次发射电予的噪_时尚妈妈_新浪博客，时尚妈妈，婚纱摄影网提供按照噪声和信号之间的关系，图像噪声可分为加性噪声和乘性噪声两大类。。。

Content included: study on the relationship between noise and cumulative noise exposure as well as low frequency noise-induced hearing loss and high frequency noise-induced hearing loss; study on the relationship between noise sensitivity as well as LFNIHL and HFNIHL.1 Study on the relationship between noise and CNE as well as LFNIHL and HFNIHL657 data concerning workers' hearing check-up were collected including such types of work as Trial pilots and Riveters.

内容包括：噪声和累积噪声剂量与语频和高频听力损伤关系的研究；噪声敏感与语频和高频听力损伤关系的研究。 1 噪声和累积噪声剂量与语频和高频听力损伤关系的研究选取成都某大型飞机制造厂试飞和铆工两个工种作业人员657名作为研究对象。其中试飞员199人(均为男性；年龄23～60岁，平均37.36岁；接噪工龄1～42年，平均接噪工龄17.68年)。

Position parameters were obtained from the simulation with the model of towed array.Based on the theory of radiated noise forming, the launch noise was simulated according to test condition in Laboratory,and the result showed the launch impulsion noise obeyed SαS distribution. The simulated noise attenuating in deep sea was analyzed with a sound loss translation model.Minimum variance distortionless response,spatially smoothed MVDR, and beam-space multiple signal classification algorithm were adopted to process the signal, hence the source level, the frequency structure and the location of the launch noise were achieved.

基于试验的实际情况，根据潜艇拖曳阵模型，仿真生成了各水听器阵元与本艇的位置关系；根据噪声源理论模型分析产生雷弹发射模拟噪声，利用SαS分布模拟武器发射冲击噪声，仿真分析模拟噪声在海洋环境中的传播衰减，对阵元信号分别利用最小方差无畸变响应法（MVDR 、空间平滑MVDR以及适应子带的波束域多重信号分类算法进行信号处理，得到发射噪声的声源级、频谱结构和方位。

The factors that influence the noise performance of lithium-based grease were researched,the cleanliness of grease is merely one of essential conditions to decrease noise,the particle size of lithium soap thickener is smaller,the noise performance of grease is better,and the low viscosity naphthene base oil has good effect to decrease noise,the polymer can improve lubricity and decrease noise.

研究了影响锂基润滑脂噪音性能的各种因素，润滑脂的清洁度只是降低噪音的必要条件之一，锂皂稠化剂的微粒越小，润滑脂的噪音性能越好，低粘度的环烷基油具有良好的降低噪音的效果，高分子聚合物可以改善润滑性能，降低噪音。

NB/ANL button. Pressing this button enables the built in noise reducing functions. There are: noise blanker only, both noise blanker and automatic noise limiter, and automatic noise limiter only.

NB/ANL button ：静噪/噪音自动限制器按钮，按下这个按钮产生减少噪音功能：仅是噪音抑制器；既是噪音抑制器又是噪音自动限制器；和仅是噪音自动限制器。

Firstly the dissertation analyses the reason of vibration and noise of the transmission gear and the box, drawing a conclusion that the change of gear mesh rigidity and transmission error are the crucial causation to engender vibration and noise of the gear-box; the main source of the noise is the syntonic noise in box vibration and noise.

本文首先分别分析了变速箱传动齿轮和变速箱箱体的振动噪声产生机理，得知产生变速箱传动齿轮振动噪声的主要因素是轮齿啮合刚度的变化和传动误差的影响；且在变速箱箱体振动噪声中自鸣噪声是汽车变速箱的主要噪声源。

Listen,point and check your answers.

听，指出并且检查你的答案。

Warming needle is one of effective treatment methods for knee arthralgia aggravated by cold,and it is simple,safety,so it should be developed in clinical acupuncture and moxibustion extensively.

但以本院科针灸门诊在2005年1月—2006年6月期间共收治膝痛患者100余例，经过临床的诊断后，其中施以温针治疗的48例，疗效显著，报道如下。1临床资料本组病例48