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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噪声地图中栅格型噪声云图被放大后会产生失真现象,且占用的存储空间较大,不利于大尺度噪声地图的精细化展示。为提升噪声云图展示效果并降低文件大小,研究双线性插值、双三次卷积插值、栅格图像矢量化方法的优缺点,提出一种基于噪声等值线平滑的矢量化优化方法。该方法利用平滑后的等值线、绘图边界、建筑物轮廓等构建矢量面要素,并根据各面要素内噪声值通过渲染得到矢量噪声云图。不同噪声云图优化方法的对比结果表明,根据基于等值线平滑的优化方法得到的矢量噪声云图对噪声传播和分布规律的展示更为清晰,数据量降为栅格数据的1/30,且噪声展示精度灵活可调,对于改善噪声地图质量、增强噪声地图实用性具有重要意义。该方法也可推广应用于绘制其他类似的专题地图以提升数据可视化效果。 相似文献
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电视台风机及风机房减振降噪治理 总被引:2,自引:0,他引:2
噪声与振动本上消除振动和噪声.本文通过对电视台转播设备噪声与振动源分析,制定出合理的噪声与振动控制方案,从而有效地解决了噪声与振动问题. 相似文献
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本文主要介绍半导体器件缺陷与噪声的关系。根据噪声电子学的知识和低频噪声检测半导体器件缺陷理论及其在实际中的应用,从原理上分析器件缺陷所引发的电路故障与噪声特性参数关系,通过对输出噪声特性参数的分析和处理达到诊断电路故障。 相似文献
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将黏性多相流理论的数值方法和球形空泡辐射噪声理论相结合,进行了非均匀入流条件下螺旋桨片空化的周期形态模拟以及螺旋桨空化单极子声源辐射噪声数值预报。采用流场数值模拟方法和声场边界元数值声学方法耦合的方法,在频域上预报非均匀入流下空化和非空化条件下螺旋桨负载噪声;通过数值预报负载噪声得到非空化条件下螺旋桨噪声,将片空化单极子声源辐射噪声和空化的负载噪声在频域上进行相加得到空化条件下的螺旋桨噪声。采用某民船桨模验证了非均匀入流下螺旋桨片空化周期形态以及空化单极子声源辐射噪声预报的准确性,然后分析了民船桨在空化和非空化条件下螺旋桨噪声的叶频和二倍叶频特征。结果表明,上述方法能有效地预报螺旋桨空化和非空化噪声的叶频特征。 相似文献
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A method is developed to directly map nanoscale “noise‐source switching” phenomena during the optoelectronic switching of phase‐separated polymer nanocomposites of tetrathiafulvalene (TTF) and phenyl‐C61‐butyric acid methyl ester (PCBM) molecules dispersed in a polystyrene (PS) matrix. In the method, electrical current and noise maps of the nanocomposite film are recorded using a conducting nanoprobe, enabling the mapping of a conductivity and a noise‐source density. The results provide evidence for a repeated modulation in noise sources, a “noise‐source switching,” in each stage of a switching cycle. Interestingly, when the nanocomposite is “set” by a high bias, insulating PS‐rich phases shows a drastic decrease in a noise‐source density which becomes lower than that of conducting TTF‐PCBM‐rich phases. This can be attributed to a trap filling by charge carriers generated from a TTF (donor)–PCBM (acceptor) complex. In addition, when the film is exposed to UV, an optical switching occurs due to chemical reactions which lead to irreversible changes on the noise‐source density and conductivity. The method provides a new insight on noise‐source activities during the optoelectronic switching of polymer nanocomposites and thus can be a powerful tool for basic noise research and applications in organic memory devices. 相似文献
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《Drug development and industrial pharmacy》2013,39(10):1045-1057
Peptide mapping is a key analytical method for studying the primary structure of proteins. The sensitivity of the peptide map to even the smallest change in the covalent structure of the protein makes it a valuable “fingerprint” for identity testing and process monitoring. We recently conducted a full method validation study of an optimized reverse-phase high-performance liquid chromatography (RP-HPLC) tryptic map of a therapeutic anti-CD4 monoclonal antibody. We have used this method routinely for over a year to test production lots for clinical trials and to support bioprocess development. One of the difficulties in the validation of the peptide mapping method is the lack of proper quantitative measures of its reproducibility. A reproducibility study may include method and system precision study, ruggedness study, and robustness study. In this paper, we discuss the use of principal component analysis (PCA) to quantitate peptide maps properly using its projected scores on the reduced dimensions. This approach allowed us not only to summarize the reproducibility study properly, but also to use the method as a diagnostic tool to investigate any troubles in the reproducibility validation process. 相似文献
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Peptide mapping is a key analytical method for studying the primary structure of proteins. The sensitivity of the peptide map to even the smallest change in the covalent structure of the protein makes it a valuable “fingerprint” for identity testing and process monitoring. We recently conducted a full method validation study of an optimized reverse-phase high-performance liquid chromatography (RP-HPLC) tryptic map of a therapeutic anti-CD4 monoclonal antibody. We have used this method routinely for over a year to test production lots for clinical trials and to support bioprocess development. One of the difficulties in the validation of the peptide mapping method is the lack of proper quantitative measures of its reproducibility. A reproducibility study may include method and system precision study, ruggedness study, and robustness study. In this paper, we discuss the use of principal component analysis (PCA) to quantitate peptide maps properly using its projected scores on the reduced dimensions. This approach allowed us not only to summarize the reproducibility study properly, but also to use the method as a diagnostic tool to investigate any troubles in the reproducibility validation process. 相似文献
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我国现采用的声环境监测和评价方法,是有一定科学理论支持的,符合当时监测技术水平条件的声环境质量监测和评价方法。随着环境科技的发展,该方法已不能很好满足环境管理部门和人民群众的需求。用城市声环境地图法来衡量声环境的质量,在技术上是先进的,成熟的,在我国实施的条件已经具备,可使声环境质量评价更密切地与判定和改善市民的生活质量与城市的宜居水平结合起来,足声环境质量评价方法向以人为本的方向展开的重大转变。 相似文献
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近年来,通过优化飞行程序降低机场飞机噪声影响成为机场环境保护的重要研究方向。文章首先建立了基于飞机“噪声-功率-距离”数据的噪声计算模型,介绍了平均飞行航迹以及连续爬升运行(Continuous Climb Opera-tion, CCO)离场程序的相关理论,最后以大型国际机场为实例,使用飞机平均飞行航迹进行噪声预测,运用综合噪声模型计算出噪声影响面积并绘制噪声影响等值线图,比较了CCO离场相对常规的标准仪表离场(Standard Instru-ment Departure, SID)的降噪效果。结果表明,CCO离场程序可有效降低机场噪声影响,在高噪声级影响区域的降噪效果更佳。 相似文献
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随着飞机适航审定关于噪声要求的逐年提高,预测部件飞行噪声声压级可以为飞机的适航审定工作提供依据,也可以为发动机的减噪设计提供参考。通过对发动机部件噪声进行预测,可以有效确定发动机的部件特性。以核心机噪声为突破口,通过对发动机核心机的静态噪声进行预测,然后经过从静态到飞行状态相关映射因素声源移动效应、声衰减等的修正,最后得到飞机在边线时的噪声值。同时可以用文中的方法预测其他部件的噪声值,整合预测出整机的噪声,可作为适航审定的依据,从而大量减少适航审定过程的投入成本。 相似文献