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不确定性 1

低衰减 1

低角估计；甚高频雷达；复杂场景；多径效应；高度估计 1

地震动衰减关系 1

大气衰减 1

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微地震信号低衰减传播

肖健,孙书廷,刘建中

《中国工程科学》 2014年第16卷第8期页码 83-87

摘要：

本文探讨了弱地震信号低衰减传播的可能性。结果表明，地下的地震信号传播介质均表现出一定的弹性，振动信号幅度在低于介质弹性限度时传播，衰减很小，表现出低衰减特征。这一特点保证了可以在地面，甚至黄土覆盖区监测到微地震信号。

关键词：微地震低衰减非弹性衰减

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Application of gamma-ray attenuation technology in density measurement of a slurry reactor

Jian XU, Weisheng WEI, Kai ZHANG

《化学科学与工程前沿（英文）》 2010年第4卷第4期页码 486-490 doi: 10.1007/s11705-010-0509-6

摘要： Axial density profile of the gas-liquid-solid mixture in a slurry bubble column was measured by gamma-ray attenuation technology. Several measures for improving measurement precision were presented based on the discussion on attenuation law. It was found that the response frequency and the ray intensity should be as high as possible to improve the measurement precision. The mass absorption coefficient depended on not the object’s thickness but the location where the object was placed between the ray source and the detector. The results showed that the density in the column decreases with the increase of column height, which indicates that the measurement by gamma-ray attenuation is reasonable.

关键词： slurry reactor axial density distribution gamma-ray attenuation technology

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microbial reductive dehalogenation with persulfate activation and oxidation (Bio-RD-PAO) for complete attenuation

《环境科学与工程前沿（英文）》 2022年第16卷第2期 doi: 10.1007/s11783-021-1457-8

摘要：

•Bio-RD-PAO can effectively and extensively remove organohalides.

关键词： Bio-RD-PAO Microbial reductive dehalogenation Persulfate Organohalide respiration Complete attenuation

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Attenuation mechanism of

Yuanqiang ZHENG,Yanchun SHI,Chang AN,Ruisheng LI,Dongjun LIU,Yuehua KE,Kairong MAO,Mingjuan YANG,Zeliang CHEN,Shorgan BOU

《农业科学与工程前沿（英文）》 2014年第1卷第4期页码 331-340 doi: 10.15302/J-FASE-2014032

摘要： Brucellosis is a worldwide zoonosis. Vaccination is the most efficient means to prevent and control brucellosis. The current licensed attenuated vaccines for animal use were developed by sequential passage in non-natural hosts that decreased virulence in its original hosts. The attenuation mechanism of these strains remains largely unknown. In the present study, we sequenced the genome of vaccine strain M5-10. Sequence analysis showed that a large number of genetic changes occurred in the vaccine strains. A total of 2854 genetic polymorphic sites, including 2548 SNP, 241 INDEL and 65 MNV were identified. Of the 2074 SNPs in coding regions, 1310 (63.2%) were non-synonymous SNPs. Gene number, percent and N/S ratios were disproportionally distributed among the cog categories. Genetic polymorphic sites were identified in genes of the operon, flagella synthesis, and virulence regulating systems. These data indicate that changes in some cog categories and virulence genes might result in the attenuation. These attenuation mechanisms also have implications for screening and development of new vaccine strains. The genetic changes in the genome represent candidate sites for differential diagnosis between these vaccine strains and other virulence ones. Transcription analysis of virulence genes showed that expression of , were reduced in M5-10 strain when compared with that in 16M. A duplex PCR targeting and was successfully used to differentiate between M5-10 and the virulent 16M strain. The genome re-sequencing technique represents a strong strategy not only for evaluation of vaccines, but also for development of new vaccines.

关键词： Brucella live attenuated vaccine attenuation differential diagnosis

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消光法测定磷酸铵盐微粒灭火剂灭火浓度研究

殷志平,刘爱华,潘仁明

《中国工程科学》 2008年第10卷第7期页码 90-95

摘要：

采用过滤称重法配合激光消光法对两种粒度的磷酸铵盐微粒灭火剂在杯式燃烧器中的灭火浓度进行了研究，得出了激光测定磷酸铵盐微粒灭火剂的质量浓度标定曲线和微粒灭火剂的灭火浓度。结果表明，在该实验条件下，平均粒度分别为6.0 μm和13.7 μm的磷酸铵盐微粒灭火剂其激光吸收发散系数K值分别为0.353 0 m²/g和0.257 3 m²/g，平均灭火质量浓度分别为32.9 g/m³和41.6 g/m³，前者的灭火效能比后者高出25 % ～ 30 %，且前者采用激光消光法测定时相对误差较小。

关键词：激光消光法过滤称重法微粒灭火剂灭火浓度

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Experimental study on wire breakage detection by acoustic emission

Limin SUN, Ji QIAN

《结构与土木工程前沿（英文）》 2011年第5卷第4期页码 503-509 doi: 10.1007/s11709-011-0132-8

摘要： This paper experimentally investigated wire breakage detection in a steel cable by acoustic emission (AE) waveform. In the experiments, the attenuation laws of waveform amplitudes were discussed based on stress wave propagation in the wire, which was generated by kNocking and wire breakage. Then the wave velocity was calculated based on the reach time of the stress wave from each sensor. Finally, based on the waveform attenuation laws and the linear position method, the amplitude and energy of the source were confirmed through the measured waveform to identify the source category. The experimental results illustrated that the stress wave from different sources has a different frequency spectrum, and the amplitude attenuation factor varied with the stress wave frequency; high frequency waves had a greater attenuation factor. Compared with the other source, the wire breakage source contained a much higher energy, and thus, the wire breakage signal can be distinguished from the other source by comparing the non-attenuation energy at the source position.

关键词： acoustic emission (AE) waveform wire breakage attenuation factor wave velocity

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ITU-R建议中几项电波传播技术模式

张明高

《中国工程科学》 2000年第2卷第7期页码 74-78

摘要：

文章介绍ITU-R建议中五项电波传播技术模式的研究情况。它包括对流层散射传输损耗统计预测方法、海事卫星移动通信海面反射衰落预测方法、电离层闪烁衰落换算方法、大气衰减简易预测方法和陆地移动通信场强预测方法。

关键词：电波传播对流层散射海面反射电离层闪烁大气衰减

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Performance analysis for a two-way relaying power line networkwith analog network coding

Yu-wen QIAN,Meng TIAN,Xue JIANG,Hua-ju SONG,Feng SHU,Jun LI

《信息与电子工程前沿（英文）》 2015年第16卷第10期页码 892-898 doi: 10.1631/FITEE.1500135

摘要： In this paper, we investigate a two-way relaying power line communication (PLC) network with analog network coding. We focus on the analysis of the system outage probability, symbol error rate, and average capacity. Specifically, we first derive the probability density function (PDF) of the received signal-to-noise ratio (SNR) with a closed form, by exploiting the statistical properties of the PLC channel. Then with the help of this PDF, we develop the outage probability, symbol error rate, and average capacity with closed forms, based on the Hermite polynomial. Simulations show that the derived analytical results are consistent with those by Monte Carlo simulation.

关键词： Power line communication Outage probability Symbol error rate Signal attenuation

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水波与淤泥质底床相互作用数值模拟——基于滞后回路特征的淤泥体流变模型

齐鹏,侯一筠

《中国工程科学》 2006年第8卷第4期页码 39-45

摘要：

应用一个滞后回路特征的半经验的淤泥体流变模型描述表面水波作用下底床软泥层的振荡运动，建立了表面水波与淤泥质底床相互作用的垂向二维耦合模型。在数值处理上，为提高数值格式对水－泥界面附近流动的分辨力，较好地再现界面附近速度梯度大的流动特点，采用垂向对数网格处理技巧。模型验证是通过计算水波波高衰减率和底床软泥体输移速度，并与有关的实验测量数据进行比较。

关键词：泥体输移波浪衰减淤泥质底床流变模型

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甚高频雷达复杂场景中目标高度和多径衰减联合估计 Research Articles

陈胜,赵永波,胡毅立,曹成虎,庞晓娇

《信息与电子工程前沿（英文）》 2022年第23卷第6期页码 937-949 doi: 10.1631/FITEE.2100003

摘要：

由于多径效应的影响，甚高频雷达低角估计是雷达领域难题之一，尤其是在反射条件未知的复杂情况下，低角估计更难解决。针对这一问题，提出一种目标高度和多径衰减联合估计算法。该算法首先利用数据本身的特性估算反射系数幅度，当该幅度估计值很小时，认为没有反射信号，然后将反射系数的相位和直达信号与反射信号之间的相位差当作同一部分，即多径相位衰减，并对其进行搜索。推导了该算法的克拉美罗界。最后，计算机仿真和实测数据处理结果表明，该算法在复杂场景下具有良好估计性能，并且在仅有单次快拍的条件下仍能较好地工作。

关键词：低角估计；甚高频雷达；复杂场景；多径效应；高度估计

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中国核电工程场地设计地震动参数确定相关问题

李小军,贺秋梅,侯春林

《中国工程科学》 2013年第15卷第4期页码 75-82

摘要：

基于中国核电工程选址和建设的实际工作，探讨了核电工程场地设计地震动参数确定几个环节中的关键问题，包括不同地震危险性分析方法的采用、地震动衰减关系的选取和设计地震动参数的综合取值等。分析了地震动衰减关系不确定性和弥散地震衰减关系等问题处理方式的变迁，比较分析了地震危险性分析确定性方法中构造地震、弥散地震的计算结果和概率方法计算结果的差异及对设计地震动参数确定的控制作用。研究表明：a.综合考虑地震危险性分析的确定性方法和概率方法的计算结果已成为中国核电工程场地地震安全性评价中确定设计地震动参数的基本思路，其中弥散地震是一个需要特殊考虑的问题；b.确定性方法和概率方法计算结果对场地设计地震动参数的控制作用受区域地震活动性强弱的影响；c.在地震活动性较弱的地区，确定性方法特别是弥散地震计算结果基本上控制着场地设计地震动参数的取值，而在地震活动性相对较强的地区，更倾向于由概率方法计算结果控制。

关键词：核电厂设计地震动确定性方法概率方法地震动衰减关系弥散地震不确定性