On the basis of the survey of underground noise in Jinggezhuang and Donghuantuo mines, Kailuan Group, noise radiation intensity, noise propagation properties and noise frequency-spectrum characteristics of underground...On the basis of the survey of underground noise in Jinggezhuang and Donghuantuo mines, Kailuan Group, noise radiation intensity, noise propagation properties and noise frequency-spectrum characteristics of underground equipment were studied at different work conditions. The result indicates that the noise source intensity surpasses the noise limit requirement of 85 dBA completely. Nearly 70% noise sources exceed the noise limit of 90 dBA, and some are over 100 dBA. Noise attenua- tion in semi-free field environment on the ground is significantly different from underground far-field environment of noise source in coal mines. Noise of these regions, where staffs are long and highly concentrated, exceeds 85 dBA, the basic noise limit. The noise frequency-spectrum presents the wideband characteristics. Especially in the main frequency of the language communication 500, 1 000 and 2 000 Hz, the octave band of noise performs obviously.展开更多
采用状态矩阵与勒让德级数联合法,同步联立Biot理论,构建多层多孔锂离子电池声传播特性理论模型,以厚1.9 mm软包钴酸锂电池为例,数值分析了荷电状态(State of Charge,SOC)对多模态频散曲线的影响规律。同时,建立了电池中的声传播特性频...采用状态矩阵与勒让德级数联合法,同步联立Biot理论,构建多层多孔锂离子电池声传播特性理论模型,以厚1.9 mm软包钴酸锂电池为例,数值分析了荷电状态(State of Charge,SOC)对多模态频散曲线的影响规律。同时,建立了电池中的声传播特性频域仿真模型,提取频域仿真中的超声导波频散曲线。此外,以体积小、柔性强的压电纤维复合材料(Macro Fiber Composite,MFC)为基础,实验探究了不同SOC对锂离子电池中声学行为的影响。采用互相关分析获取电池放电过程中声波渡越时间的偏移规律,建立了1.9 mm软包钴酸锂电池的声学波动行为与电池SOC间的映射关系。展开更多
利用吕宋海峡附近海区温盐数据的数值模型进行声传播模拟计算的方法,根据相应的声速剖面及声传播损失,分析台风对声传播特性的影响。结果显示,2010年第10号台风"莫兰蒂"过境时,海洋环境对台风的响应较为迅速,海洋表层的温度...利用吕宋海峡附近海区温盐数据的数值模型进行声传播模拟计算的方法,根据相应的声速剖面及声传播损失,分析台风对声传播特性的影响。结果显示,2010年第10号台风"莫兰蒂"过境时,海洋环境对台风的响应较为迅速,海洋表层的温度和盐度变化剧烈,而声速及传播损失的变化较温度盐度缓慢。分析表明:台风过境会导致表面声速减小,深海声道最小声速增大,声传播损失增大,深海声道原第一会聚区位置最小声能损失增大5 d B,台风过境导致声线第一反折点位置下移,第一会聚区消失,使声传播距离缩短。展开更多
基金Supported by the National Natural Science Foundation of China （50974061） the Natural Science Foundation of Hebei Province （E2009001420）
文摘On the basis of the survey of underground noise in Jinggezhuang and Donghuantuo mines, Kailuan Group, noise radiation intensity, noise propagation properties and noise frequency-spectrum characteristics of underground equipment were studied at different work conditions. The result indicates that the noise source intensity surpasses the noise limit requirement of 85 dBA completely. Nearly 70% noise sources exceed the noise limit of 90 dBA, and some are over 100 dBA. Noise attenua- tion in semi-free field environment on the ground is significantly different from underground far-field environment of noise source in coal mines. Noise of these regions, where staffs are long and highly concentrated, exceeds 85 dBA, the basic noise limit. The noise frequency-spectrum presents the wideband characteristics. Especially in the main frequency of the language communication 500, 1 000 and 2 000 Hz, the octave band of noise performs obviously.
文摘利用吕宋海峡附近海区温盐数据的数值模型进行声传播模拟计算的方法,根据相应的声速剖面及声传播损失,分析台风对声传播特性的影响。结果显示,2010年第10号台风"莫兰蒂"过境时,海洋环境对台风的响应较为迅速,海洋表层的温度和盐度变化剧烈,而声速及传播损失的变化较温度盐度缓慢。分析表明:台风过境会导致表面声速减小,深海声道最小声速增大,声传播损失增大,深海声道原第一会聚区位置最小声能损失增大5 d B,台风过境导致声线第一反折点位置下移,第一会聚区消失,使声传播距离缩短。
