共查询到19条相似文献,搜索用时 125 毫秒
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城市噪声地图系统研究及试验性应用 总被引:2,自引:0,他引:2
对城市噪声地图系统建立进行框架性研究,并在此基础上开展试验性应用。提出在城市中建立噪声地图系统的必要性和其功能性,重点分析了系统的组成和建立步骤、关键技术和应用前景。对噪声地图系统在城市噪声的管理、噪声控制措施的优化和促进声环境质量的预警预报方面具有积极的探索意义。 相似文献
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声音存在于城市内的自然和人为环境中,声音来源可分为三个大类形:大自然声诸如风、雨、雷暴等;生命之声诸如鸟类、昆虫、宠物和动物发出的声音;人为之声如人声、音乐声、交通噪声、通风系统之噪声、建筑和拆卸工程之噪声、贸易活动产生的噪声。在最近几年,声音漫步已成为表征城市声景的方法之一。声音漫步通常通过一群人在被研究区内有代表性的典型路径的漫步。漫步者把声音录下来,也将在路径上听到的声音特点和来源记录,以及拍摄照片和在地图上标示。文章旨在为声音漫步提出一个实用指南,方便它成为城市音景的鉴定工具。 相似文献
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针对高速飞行器飞行条件下的噪声、振动环境恶劣、复杂、难预示的问题,提出了基于声振传递的飞行器飞行条件下的噪声、振动环境预示方法。采用数值仿真、脉动压力风洞试验或工程分析等方法,获取飞行器在典型工况下的舱外脉动压力场;通过噪声试验或声振耦合仿真分析的方法,得到飞行器声振传递特性;根据获得的舱外脉动压力和声振能量传递特性,结合具体飞行参数得到实际飞行条件下的飞行器声振预示环境。采用该方法对某飞行器开展了振动环境预示研究,经地面及飞行试验验证振动环境量级预示精度可达1.6 dB。提出的基于声振传递的飞行声振环境预示方法可以广泛应用在导弹、火箭等飞行器的精细化环境设计中,对于提高飞行器总体性能、环境适应性和飞行可靠性具有重要的工程意义。 相似文献
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以某城市轨道交通高架低矮弧形声屏障作为研究对象,分别选取有、无声屏障断面,开展列车通过时的噪声测试;基于有限元法、边界元法和统计能量分析法,建立轨道交通高架综合噪声预测模型并进行了试验验证。基于测试结果和预测结果,研究了城市轨道交通高架噪声的空间分布规律,分析了低矮弧形声屏障的降噪特性,探讨了低矮弧形声屏障对梁侧噪声分布的影响。研究结果表明:在无声屏障断面的情况下,轨面以下测点主要受低频桥梁结构噪声的影响,噪声随距离的衰减速度较慢,距离每增大一倍,噪声衰减约2.44 dB(A);轨面以上测点主要受高频轮轨噪声影响,噪声随距离的衰减速度较快,距离每增大一倍,噪声衰减约5.68 dB(A);低矮弧形声屏障对中高频噪声具有较好的降噪效果,但增大了低频噪声,这可能是由于声屏障的二次结构噪声辐射所导致的;低矮弧形声屏障在距离线路中心线7.5 m, 25 m处的插入损失分别约为5~8 dB(A)和2~6 dB(A);低矮弧形声屏障在梁侧插入损失约为4~6 dB(A),由于声屏障振动辐射二次结构噪声,桥梁跨中断面局部区域噪声增大。 相似文献
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基于对高速公路通城市路段交通噪声现状、车辆源强的调查,针对通城市路段高速公路声环境敏感目标空间分布特点,开展噪声综合控制对策的研究,从土地、城市和交通规划相结合的视角规划控制,采取低噪声路面、声屏障、临街建筑噪声防护等技术控制,结合限速、禁鸣等多种管理手段,提出通城市路段的高架复合道路交通噪声综合治理对策,对提升交通运输噪声污染控制效果、提高沿线居民满意度具有指导意义。 相似文献
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针对传统声压级对车内噪声主观性考虑不足的缺陷,提出符合人双耳特性的虚拟车内噪声特征响度预测及声源识别方法。根据某重型商用车驾驶室内低频轰鸣声严重的问题,基于Zwicker响度模型,在matlab中建立频域的混响场特征响度计算模型。结合路试实验激励数据和驾驶室有限元声-固耦合模型,对驾驶室内噪声响度分布和响度结构板块贡献量进行计算,识别不同板材振动产生的辐射噪声分量对驾驶室内噪声品质频谱特性的影响。实验结果表明:相对于声压级,采用响度作为分析参数提高了驾驶室内噪声源识别精度,指导结构优化设计,改善车内声学品质具有更好的效果。 相似文献
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Wasim Ullah Khan Yigang He Muhammad Asif Zahoor Raja Naveed Ishtiaq Chaudhary Zeshan Aslam Khan Syed Muslim Shah 《计算机、材料和连续体(英文)》2021,67(1):815-834
Abstract In this paper, a novel design of the flower pollination algorithm is presented for model identification problems in nonlinear active noise control systems. The recently introduced flower pollination based heuristics is implemented to minimize the mean squared error based merit/cost function representing the scenarios of active noise control system with linear/nonlinear and primary/secondary paths based on the sinusoidal signal, random and complex random signals as noise interferences. The flower pollination heuristics based active noise controllers are formulated through exploitation of nonlinear filtering with Volterra series. The comparative study on statistical observations in terms of accuracy, convergence and complexity measures demonstrates that the proposed meta-heuristic of flower pollination algorithm is reliable, accurate, stable as well as robust for active noise control system. The accuracy of the proposed nature inspired computing of flower pollination is in good agreement with the state of the art counterpart solvers based on variants of genetic algorithms, particle swarm optimization, backtracking search optimization algorithm, fireworks optimization algorithm along with their memetic combination with local search methodologies. Moreover, the central tendency and variation based statistical indices further validate the consistency and reliability of the proposed scheme mimic the mathematical model for the process of flower pollination systems. 相似文献
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来自于通讯或测试系统中的噪声和外界环境干扰,对控制系统可转化为一种随机起伏的电信号,噪声对于信息的传输和处理有很大影响.对噪声的来源及如何在控制系统中消除进行了分析,并引入扰动补偿后对控制系统进行仿真,结果表明:扰动补偿控制可以减弱噪声对跟踪系统引起的误差. 相似文献
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Noise in microelectromechanical system resonators 总被引:2,自引:0,他引:2
Vig JR Kim Y 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1999,46(6):1558-1565
Microelectromechanical system (MEMS) and nanoelectromechanical system (NEMS) based resonators and filters, ranging in frequencies from kHz to GHz, have been proposed. The question of how the stabilities of such resonators scale with dimensions is examined in this paper, with emphasis on the noise characteristics. When the dimensions of a resonator become small, instabilities that are negligible in macro-scale devices become prominent. The effects of fluctuations in temperature, adsorbing/desorbing molecules, outgassing, Brownian motion, Johnson noise, drive power and self-heating, and random vibration are explored. When the device is small, the effects of fluctuations in the numbers of photons, phonons, electrons and adsorbed molecules can all affect the noise characteristics. For all but the random vibration-induced noise, reducing the dimensions increases the noise. At submicron dimensions, especially, the frequency noise due to temperature fluctuations, Johnson noise, and adsorption/desorption are likely to limit the applications of ultra-small resonators. 相似文献
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