查询词典 noise-power-ratio

This paper introduces the causes of noise generation and propagation of indoor water supply and sewerage system , probes into the corresponding solution of controlling indoor noise, mainly discusses water pump house oscillation reducing and noise isolating, selection of drain pipe material and control of velocity and pressure of water supply pipe.

介绍了建筑室内给水排水系统噪声产生与传播的原因，探讨了控制建筑室内噪声的相应对策，重点论述了给水泵房的设置、水泵机组的减振隔声、排水管材的选择、给水管道流速和压力的控制等内容。

This paper reviewed the advances of noise barrier structure in China, and illustrated the development of multiple-edged, T-shaped and Y-shaped top structures used for noise barriers abroad. The development of some new top structures, such as soft surface, quadratic residue diffusers surface of noise barriers was also introduced.

作者对国内声屏障结构形式的现状进行了分析，介绍了国外常见的多重边、T型、Y型等顶部结构的发展情况，同时介绍了声学软表面、平方余数序列表面等新型顶部结构的发展状况。

According to the characteristics presented by armed helicopters during cruising or searching for ground targets, this paper has established the mean-square deviation stationary random model of helicopter tracks. It is an important method to decorrelate the measure noise by estimating the parameters of the color noise online. Kalman filtering and forecasting have been made with helicopter tracks. The simulated study has been carried out on helicopter tracks under the condition of color noise. It is very difficult to get an accurate and reliable prediction when the data is very limited. The paper make use of the theory of grey system to resolve the problem of prediction of helicopter tracks, establishing the GM model of grey systems and the cumulative residual error model of n degree, then correcting the GM forecast model. In the period of sampling, GM model and residual error model have been established on line to improve prediction precision.

结合武装直升机在巡航或搜索地面目标的特点，给出直升机航迹模型为协方差平稳随机模型，在线估计有色噪声参数，对测量噪声去相关，对直升机航迹进行卡尔曼滤波与预估，最后对有色噪声条件下的航迹进行了仿真研究；在数据非常有限的情况下，准确地预测又很困难，本文提出了用灰色系统理论解决直升机航迹预测问题，建立了灰色系统GM预测模型和n次累加残差模型并对GM预测模型进行修正，在每个采样期间内，实时在线建立GM预测模型和残差模型以提高预测精度。

Proposed a DHCM for extracting targets′tracks from 3-Dimensional (3D) data, and made a detailed performance analysis on the DHCM′s detection probability, noise rejection capability and computation burdens. Theoretical analyses indicate that the DHCM has a high noise rejection capability, and has neural network structure, hence has stronger adaptivity and robust to noise properties.

理论分析表明，该方法具有较高的噪声抑制能力，并具有神经网计算结构，因而，对噪声特性具有较强的自适应能力和稳健性。3）基于有向高阶相关的方法，提出了一种用于在红外噪声中检测、跟踪低信噪比点目标的方案。

Chapter four studies the chaotic responses in a system consisting of simple pendulum and harmonic oscillator under bounded noise excitation. Firstly, the Melnikov function of the two-degree-of-freedom system under Hamiltonian perturbation is derived. The essential condition of the autonomous system for the probable onset of chaos is obtained, the Poincare maps of the system under small Hamiltonian perturbation and the effect of increasing perturbation on the Poincare maps are studies. Then for the non-autonomous system under damping and harmonic or bounded noise excitation, the largest Lyapunov exponent and Poincare maps are calculated. From the analysis of the largest Lyapunov exponent, the critical criterion for the onset of chaos, and the conclusion that the threshold of bounded noise amplitude for the onset of chaos in the system increases as the intensity parameter of Wiener process increases are obtained. The result from the analysis of Poincare maps is in agreement with that obtained from the Largest Lyapunov exponent. The effect of varying damping coefficient and intensity parameter of Wiener process is also analyzed.

第四章研究了有界噪声激励下的两自由度单摆—谐振子系统的混沌运动，首先推导了该两自由度系统仅在Hamilton扰动下的Melnikov函数，得到该自治系统可能产生混沌的必要条件；研究了该系统在小的Hamilton扰动和增大摄动情形下的Poincare截面；然后对有阻尼、谐和或有界噪声激励下的非自治系统数值计算了其最大Lyapunov指数和Poincare截面；从Lyapunov指数分析得到了这个两自由度系统产生混沌运动的临界条件及产生混沌的临界激励幅值随Wiener过程强度参数值的增大而增大的结论，Poincare截面分析的结果亦符合Lyapunov指数分析的结论；研究了Wiener过程强度参数、阻尼系数变化对Poincare截面的影响。

Article 36 To build expressways, urban overhead road and light-tract lines that traverse areas where there are concentrated noise-sensitive structures and that might produce environmental noise pollution, sound barriers shall be erected or other effective measures shall be taken to control environmental noise pollution.

第三十六条建设经过已有的噪声敏感建筑物集中区域的高速公路和城市高架、轻轨道路，有可能造成环境噪声污染的，应当设置声屏障或者采取其他有效的控制环境噪声污染的措施。

From the stationary, Gaussian and spectral constructural point of view, we considered that the IR noise can be described with fratcal Gaussian noise , and proposed a scheme for simulating IR noise used in simulation studies.

该方案可对帧间相关性进行模拟。2）提出了一种用于从三维数据中提取目标轨迹的有向高阶相关方法，并对该方法的检测概率、噪声抑制能力及计算量等性能进行了较详细的分析。

Chapter six, in consideration that the worm tongue structure is a key factor affecting noise generation, the mathematical model of centrifugal fan noise increment that is produced by worm tongue structure is established by using of the D—optimizng technology and dimension analysis method, and the spectral property of fan noise produced by worm tongue structure is analysed.

第六章，针对离心风机蜗舌是影响离心风机噪声的关键因素的特点，采用D—最优化技术并结合量纲分析法，建立了离心风机蜗舌引起的噪声增量与蜗舌结构参数的数学模型，并分析了蜗舌结构参数及其对叶轮声辐射频谱特性的影响。

According to the practical observation method of road traffic noise and by using the micro traffic flow theory, a dynamic and stochastic model, which can predict equivalent noise level and statistical noise levels from complex vehicle flow on a multi-lanes road, is established in this paper.

本文根据我国道路交通噪声的实际观测方法，通过引入微观交通流理论，建立了一种可用于多车道混合车流等效声级和统计声级预测的动态随机模型。

Low-level noise can cause higher probability of subjective annoyance. It"s very slightly to people"s health, sleeping and working about the low frequency noise. It was compared with the high frequency noise caused by traffic about sleep, work and rest.

研究结果表明：居住区低频低噪声引起的烦恼度不容忽视，在低频低噪声环境下仍能引起较高的烦恼概率；低频低噪声对人的睡眠、行为及主观生理不适感有影响；低频噪声烦恼度与中高频噪声烦恼度的研究结果在对睡眠、工作及休息上有差异。

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。