座椅下圆柱型多孔送风器的噪声测试和分析

通过对剧院座椅下圆柱型多孔送风器噪声的测试及其结果分析,指出这种送风器的噪声能符合剧院允许噪声标准,可以在剧院空调中应用。     

风机噪声的理论分析与解决方案

对由变频器输出中的高次谐波造成电动机运转噪声增大及载波频率与风机共振造成风机噪声的原因进行了理论分析，提出了解决方案。     

青岛市市南区道路交通噪声现状与趋势分析

环境噪声问题已成为社会关注的焦点.通过监测和统计数据,从宏观上对青岛市市南区道路交通噪声现状及趋势进行分析,提出相应建议,以期对改善交通噪声有所帮助.     

Community response to environmental noise and the impact on cardiovascular risk score

Objective

The objective of our study was to investigate and evaluate the relationship between road traffic noise and cardiovascular risk.

Methods

The study sample (n = 659; 36.9% male, 63.1% female university students, mean age 22.83 ± 1.58 years) included a group exposed to road traffic noise (n = 280, L_eq,24 h = 67 ± 2 dB(A)) and a control group (n = 379, L_eq,24 h = 58.7 ± 6 dB(A)). Subjective response was determined by a validated noise annoyance questionnaire. The ten year risk of developing a coronary heart disease event was quantified as an evaluation of cardiovascular risk (SCORE60, Framingham 10-year risk estimation and projection to the age of 60, relative risk SCORE chart).

Results

Cardiovascular risk scores were significantly higher in the exposed group based on the Framingham scores projected to the age of 60, SCORE60 (AOR = 2.72 (95% CI = 1.21-6.15)) and the relative risk SCORE chart (AOR = 2.81 (1.46-5.41)).

Conclusions

These findings highlight the association between road traffic noise and cardiovascular risk.     

某甲级写字楼VAV空调机房噪声治理的体会

甲级写字楼对噪声标准要求较高,采用变风量(VAV)空调系统必须对噪声源及消声、隔声措施重点关注;噪声治理是系统工程,需要隔声、吸音、消声措施同时实施。噪声治理成本极高,且由于各种条件限制,后期治理未必能达到理想效果。     

城市道路交通噪声的防治

分析了城市道路交通噪声的危害,介绍了减少交通噪声的几种控制措施,提出对城市道路交通噪声综合防治的观点,从而把城市道路交通噪声控制在容许范围内,为市民提供一个良好的生活环境.     

Stochastic response of hysteretic systems

This paper deals with approximate stochastic response of hyseretic structures under white noise excitation, based on It stochastic differential equations. Instead of the original system an equivalent nonlinear system is considered, in which the drift vector is given by a series expansion of the order n 1 in terms of the state variables. n = 1 represents the well-known case of equivalent linearization. Components in the drift vector representing the nonanalytical constitutive equations are replaced by a cubic polynomial expansion. The hierarchy of statistical moment equations is closed by a cumulant neglect closure scheme. The method has been applied to a bilinear single degree-of-freedom system subjected to white noise excitation, for which an equivalent system with a cubic series expansion to the constitutive equation is considered. The results obtained are compared with those of numerical simulation and alternative methods, and they provide substantial improvements compared to equivalent linearization.     

城市地下商场声环境调查评价

本文在城市地下建筑声环境调查的基础上，就我国南北几个城市地下商业建筑声环境状况进行分析和评价，并提出城市人防地下商场声环境评价标准和处理建议。     

首都机场航站楼3层内区空调新风系统改造分析

内区办公室采用风机盘管加新风系统，空调系统运行时少数办公室出现噪声大、空气品质不良等问题。对空调新风系统作了测试和验算，分析了出现问题的原因，制定出改造方案，采用条缝型风口替代格栅型风口，并加大风口尺寸，增加静压消声箱和排风装置，改造后实测数据表明问题得到较好解决。     

色噪声背景下基于声矢量阵列孔径扩展的相干目标波达方向估计

在目标波达方向(DOA)估计中,更大的阵列孔径往往能够获得更高估计分辨率和估计精度.然而,在色噪声背景或相干目标情况下,子空间类DOA估计算法性能急剧下降.针对这个问题,采用2个分置且相互垂直的均匀线性矢量阵列,通过阵列之间的协方差矩阵前向/后向平滑进行解相干预处理,并消除有色噪声的干扰;然后利用传播因子方法(PM)得...