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压电圆环径向弯曲振动与激励研究

物理学报 2024年第19期73卷 229-243页

作者：潘瑞莫喜平柴勇张秀侦田芝凤中国科学院声学研究所海洋声学技术实验室北京100190 中国科学院大学物理科学学院北京100049

针对压电圆环换能器的径向弯曲振动问题,从薄壳理论出发进行相关数理推导,讨论了压电效应的影响及电学短路与开路下的弯曲振动方程.进行相关解析求解,给出了两种条件下的多阶谐振频率预测公式,并利用有限元法分析了两式的适用范围.使用... 详细信息

针对压电圆环换能器的径向弯曲振动问题,从薄壳理论出发进行相关数理推导,讨论了压电效应的影响及电学短路与开路下的弯曲振动方程.进行相关解析求解,给出了两种条件下的多阶谐振频率预测公式,并利用有限元法分析了两式的适用范围.使用模态理论,定义模态权值函数,研究了电学激励条件对多阶弯曲振动模态的具体影响,得到了单模态激励、局部等幅激励和单端激励等作用于多个目标模态的有效方法.经有限元仿真(FEM)、实验与理论对比验证,三者吻合较好,相关结论可以为压电圆环弯曲振动模态识别、模态激励的精细化调控提供理论基础.

关键词：压电圆环换能器弯曲振动薄壳理论模态激励

Ancient DNA unravels species identification from Laosicheng site,Hunan Province,China,and provides insights into maternal genetic history of East Asian leopards

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Zoological Research 2024年第1期45卷 226-229页

作者： Ming zhang Cai-Hui Wang Yu-Xin Zheng Qi-Gao Jiangzuo Ye-Mao Hou Peng Cao Qing-Yan Dai Ruo-Wei Yang Feng Liu Xiao-tian Feng Lin-Heng Mo Qiao-Mei Fu China-Central Asia"the Belt and Road"Joint Laboratory on Human and Environment Research Key Laboratory of Cultural Heritage Research and ConservationSchool of Culture HeritageNorthwest UniversityXi’anShaanxi 710127China Shanghai Qi zhi Institute Shanghai 200232China College of Life Sciences Northwest UniversityXi’anShaanxi 710127China Key Laboratory of Vertebrate Evolution and Human Origins Institute of Vertebrate Paleontology and PaleoanthropologyCenter for Excellence in Life and PaleoenvironmentChinese Academy of SciencesBeijing 100044China Cultural Relics and Archaeology Institute of Hunan ChangshaHunan 410083China University of the Chinese Academy of Sciences Beijing 100049China

DEAR EDITOR,The Laosicheng site in Yongshun County,Hunan Province,China,plays an important role in elucidating the animal population composition of the region prior to the middle Qing Dynasty(approximately 300 years ago).This site has yielded a substantial number of animal bones,11960 of which have been identified to the species level,serving as direct evidence of ancient animal populations(Hunan Provincial Institute of Cultural Relics and Archaeology,2.18).

关键词： Hunan Ancient insight

Wafer-scale 30°twisted bilayer graphene epitaxially grown on Cu_(0.75)Ni_(0.2.)(111)

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Chinese physics B 2024年第6期33卷 467-471页

作者：马鹏程张翱甄洪润江志诚杨逸尘丁建阳刘正太刘吉山沈大伟于庆凯刘丰张学富刘中灏 school of Physical Science and Technology Ningbo UniversityNingbo 315211China Institute of High-Pressure physics Ningbo UniversityNingbo 315211China National Key Laboratory of Materials for Integrated Circuits Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230029China

Twisted bilayer graphene(TBG) has been extensively studied because of its novel physical properties and potential application in electronic *** we report the synthesis and characterization of 300 TBG naturally grown on Cu_(0.75)Ni_(0.2.)(111) film and investigate the electronic structure by angle-resolved photoemission *** with other substrates,our TBG with a wafer scale is acquired with a shorter growth *** Fermi velocity and energy gap of Dirac cones of TBG are comparable with those of a monolayer on Cu_(0.85)Ni_(0.15)(111).The signature of moré lattices has not been observed in either the low-energy electron diffraction patterns or the Fermi surface map within experimental resolution,possibly due to different Cu and Ni contents in the substrates enhancing the different couplings between the substrate and the first/second layers and hindering the formation of a quasiperiodic structure.

关键词： twisted bilayer graphene electronic structure Cu/Ni(111)

基于X射线荧光光谱的温稠密物质离化分布实验方法研究

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物理学报 2024年第1期73卷 241-247页

作者：张志宇赵阳青波张继彦林成亮杨国洪韦敏习熊刚吕敏黄成武朱托宋天明赵妍张玉雪张璐李丽灵杜华冰车兴森黎宇坤詹夏宇杨家敏中国工程物理研究院激光聚变研究中心绵阳621900 北京应用物理与计算数学研究所北京100088

受温度及密度等环境效应影响,温稠密物质的电子结构发生显著变化,其理论描述非常复杂,精密实验测量亦极其困难.本文发展了基于X射线荧光光谱研究温稠密物质离化分布的实验方法,结合理论研究有助于深入理解温稠密物质的电子结构变化.在... 详细信息

受温度及密度等环境效应影响,温稠密物质的电子结构发生显著变化,其理论描述非常复杂,精密实验测量亦极其困难.本文发展了基于X射线荧光光谱研究温稠密物质离化分布的实验方法,结合理论研究有助于深入理解温稠密物质的电子结构变化.在万焦耳激光装置上,设计特殊构型黑腔复合加载产生数十eV、近固体密度的稠密Ti物质,利用激光辐照V产生的热发射线泵浦Ti的荧光,并采用晶体谱仪诊断样品的X射线荧光光谱.实验中获得冷样品和加载样品的荧光光谱,观测到加载样品K_(α)及K_(β)荧光谱线相对于冷样品光谱在高能侧的显著变化,结合理论计算解释了加载样品荧光谱线的变化主要来源于其温度上升后离化分布的改变,建立了基于X射线荧光光谱的温稠密物质离化分布实验研究能力.

关键词：温稠密物质电子结构离化分布 X射线荧光光谱

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区域选取对图像信息法可预测性的影响

地震学报 2024年第2期46卷 208-225页

作者：田唯熙张永仙张盛峰张小涛中国地震局地震预测研究所北京100003 中国地震台网中心北京100045

图像信息(PI)法是一种基于统计物理学的地震预测方法,因其对中长期地震预测有较好的效果已在国内外广泛应用。PI方法在计算过程中对选取区域的所有网格参量进行了归一化,因此不同的区域选取会产生PI热点结果的变化。本文基于中国地震台... 详细信息

图像信息(PI)法是一种基于统计物理学的地震预测方法,因其对中长期地震预测有较好的效果已在国内外广泛应用。PI方法在计算过程中对选取区域的所有网格参量进行了归一化,因此不同的区域选取会产生PI热点结果的变化。本文基于中国地震台网中心自1970年以来的全国M_(S)≥3.0地震目录,采用5年尺度的“异常学习时段”和“预测时间窗”以及1年尺度的滑动时间步长,以南北地震带2.16年以来发生的M_(S)≥6.0地震的回溯性预测检验为例,研究了不同空间范围的选取对PI方法地震预测效能的影响。地震预测效能检验采用R值评分法和受试者工作特征(ROC)检验方法。结果显示:①在其它计算参数相同的情况下,不同的区域选取对PI预测结果有较大影响;②利用R值评分和ROC检验方法对不同研究区的预测效能进行评估时,区域内部地震活动性差异小的区域预测效果较好,而对于地震活动性存在较大差异的区域,地震活动性高的区域内发生的地震更容易被预测,推测导致这一结果的可能原因是地震活动性较强的区域出现的异常更显著,而算法里的归一化过程会抑制地震活动性较低区域出现的异常,从而造成漏报;③对于具体的目标地震,震中附近的PI热点图像会经历演化,因此利用PI方法向前预测时要结合多个时间窗口进行综合预测;④不同于其它天然构造地震的热点演化趋势,2.19年四川长宁M_(S)6.0地震和2.2.年四川泸县M_(S)6.0地震震中附近热点反复出现、消失,可能与人工活动有关;⑤滇西南地区、海原断裂中东部附近、小江断裂中部地区、龙门山断裂南部和小江断裂东北部地区存在持续出现的PI热点,这些区域为值得关注的M_(S)≥6.0地震发震区域。

关键词：图像信息(PI)法南北地震带地震可预测性强震预测 R 值评分 ROC 检验

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An overview for monitoring and prediction of pathogenic microorganisms in the atmosphere

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Fundamental Research 2024年第3期4卷 430-441页

作者： Jianping Huang Danfeng Wang Yongguan Zhu Zifeng Yang Maosheng Yao Xiaoming Shi Taicheng An Qiang zhang Cunrui Huang Xinhui Bi Jiang Li Zifa Wang Yongqin Liu Guibing Zhu Siyu Chen Jian Hang Xinghua Qiu Weiwei Deng Huaiyu {2. Tengfei zhang {2.mu Chen Sijin Liu Xinbo Lian Bin Chen Beidou zhang Yingjie Zhao Rui Wang Han Li Collaborative Innovation Center for Western Ecological Safety College of Atmospheric SciencesLanzhou UniversityLanzhou 730000China Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China National Clinical Research Center for Respiratory Disease Guangzhou Institute of Respiratory HealthFirst Affiliated Hospital of Guangzhou Medical UniversityState Key Laboratory of Respiratory Disease(Guangzhou Medical University)Guangzhou 510230China College of Environmental Sciences and Engineering Peking UniversityBeijing 100871China China CDC Key Laboratory of Environment and Population Health National Institute of Environmental HealthChinese Center for Disease Control and PreventionBeijing 100021China Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health School of Environmental Science and EngineeringInstitute of Environmental Health and Pollution ControlGuangdong University of TechnologyGuangzhou 510006China Ministry of Education Key Laboratory for Earth System Modeling Department of Earth System ScienceTsinghua UniversityBeijing 100084China Vanke school of Public Health Tsinghua UniversityBeijing 100084China State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100021China State Key Laboratory of Atmospheric Boundary Layer physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Center for Pan-third Pole Environment Lanzhou UniversityLanzhou 730000China College of Atmospheric Sciences Lanzhou UniversityLanzhou 730000China school of Atmospheric Sciences Sun Yat-sen Universityand Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 510640

Corona virus disease 2.19(COVID-19)has exerted a profound adverse impact on human *** have demonstrated that aerosol transmission is one of the major transmission routes of severe acute respiratory syndrome coronavirus 2.SARS-CoV-2..Pathogenic microorganisms such as SARS-CoV-2.can survive in the air and cause widespread infection among *** monitoring of pathogenic microorganism transmission in the atmosphere and accurate epidemic prediction are the frontier guarantee for preventing large-scale epidemic *** of pathogenic microorganisms in the air,especially in densely populated areas,may raise the possibility to detect viruses before people are widely infected and contain the epidemic at an earlier *** multi-scale coupled accurate epidemic prediction system can provide support for governments to analyze the epidemic situation,allocate health resources,and formulate epidemic response *** review first elaborates on the effects of the atmospheric environment on pathogenic microorganism transmission,which lays a theoretical foundation for the monitoring and prediction of epidemic ***,the monitoring technique development and the necessity of monitoring pathogenic microorganisms in the atmosphere are summarized and ***,this review introduces the major epidemic prediction methods and highlights the significance to realize a multi-scale coupled epidemic prediction system by strengthening the multidisciplinary cooperation of epidemiology,atmospheric sciences,environmental sciences,sociology,demography,*** summarizing the achievements and challenges in monitoring and prediction of pathogenic microorganism transmission in the atmosphere,this review proposes suggestions for epidemic response,namely,the establishment of an integrated monitoring and prediction platform for pathogenic microorganism transmission in the atmosphere.

关键词： Aerosol transmission Epidemic monitoring methods Epidemic prediction modelsEpidemic response Multidisciplinary cooperation

Study of giant magnetoresistance and giant electroresistance of carbon based thin film

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Rare Metals 2006年第Z1期25卷 617-620页

作者： zhang Xiaozhong tian Peng {2. Qingzhong Laboratory of Advanced Materials Department of Materials Science and Engineering Tsinghua University Beijing 100084 China Laboratory of Advanced Materials Department of Materials Science and Engineering Tsinghua University Beijing 100084 China Laboratory of Advanced Materials Department of Materials Science and Engineering Tsinghua University Beijing 100084 China College of physics Science and Technology China University of Petroleum Dongying 257061 China

Using pulsed laser deposition, Fex-C1-x films on Si (100) substrates were prepared. At T=300 K and B=5 T a large positive MR of 138% was found in Fe0.011-C0.989 film. It is also found that when T2.8 K, the MR of Fe0.011-C0.989 film is negative and when 2.8 K2.00 Oe, the MR is 11.5% at 2.5 mA and is 35% at about 35 V. The material has also a giant electroresistance of 500% at 8 V.

关键词： magnetoresistance electroresistance carbon based film

Roadmap for rechargeable batteries:present and beyond

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Science China Chemistry 2024年第1期67卷 13-42页

作者： Sen Xin Xu zhang Lin Wang Haijun Yu Xin Chang Yu-Ming Zhao Qinghai Meng Pan Xu Chen-Zi Zhao Jiahang Chen Huichao Lu Xirui Kong Jiulin Wang Kai Chen Gang Huang Xinbo zhang Yu Su Yao Xiao Shu-Lei Chou Shilin zhang Zaiping Guo Aobing Du Guanglei Cui Gaojing Yang Qing Zhao Liubing Dong Dong Zhou Feiyu Kang Hu Hong Chunyi zhi zhizhang Yuan Xianfeng Li Yifei Mo Yizhou Zhu Dongfang Yu Xincheng Lei Jianxiong Zhao Jiayi Wang Dong Su Yu-Guo Guo Qiang zhang Jun Chen Li-Jun Wan CAS Key Laboratory of Molecular Nanostructure and Nanotechnology CAS Research/Education Center for Excellence in Molecular SciencesBeijing National Laboratory for Molecular Sciences(BNLMS)Institute of ChemistryChinese Academy of Sciences(CAS)Beijing 100190China University of Chinese Academy of Sciences.beijing 100049 China Institute of Advanced Battery Materials and Devices Faculty of Materials and ManufacturingBeijing University of TechnologyBeijing 100124China Key Laboratory of Advanced Functional Materials Ministry of EducationBeijing University of TechnologyBeijing 100124China beijing Key Laboratory of Green Chemical Reaction Engineering and Technology Department of Chemical EngineeringTsinghua UniversityBeijing 100084China State Key Laboratory of Chemistry and Utilization of Carbon-Based Energy Resources College of ChemistryXinjiang UniversityUrumqi 830046China Department of Chemical Engineering Shanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChangchun 130022China Institute for Carbon Neutralization College of Chemistry and Materials EngineeringWenzhou UniversityWenzhou 325035China school of Chemical Engineering and Advanced Materials The University of AdelaideAdelaide 5000Australia Qingdao Industrial Energy Storage Research Institute Qingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesQingdao 266101China Frontiers Science Center for New Organic Matter Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education)College of ChemistryNankai UniversityTianjin 300071China College of Chemistry and Materials Science Jinan UniversityGuangzhou 511443China Tsinghua Shenzhen International Graduate school Tsinghua UniversityShenzhen 518055China Department of Materials Science and Engineering City University of Hong KongHong Kong 999077China Division of Energy Storage Dalian National Laboratory for Clean Energy(DNL)Dalian Institute of Chem

Rechargeable batteries currently hold the largest share of the electrochemical energy storage market,and they play a major role in the sustainable energy transition and industrial decarbonization to respond to global climate *** to the increased popularity of consumer electronics and electric vehicles,lithium-ion batteries have quickly become the most successful rechargeable batteries in the past three decades,yet growing demands in diversified application scenarios call for new types of rechargeable *** efforts are made to developing the next-generation post-Li-ion rechargeable batteries,which include,but are not limited to solid-state batteries,lithium–sulfur batteries,sodium-/potassium-ion batteries,organic batteries,magnesium-/zinc-ion batteries,aqueous batteries and flow *** the great achievements,challenges persist in precise understandings about the electrochemical reaction and charge transfer process,and optimal design of key materials and interfaces in a *** roadmap tends to provide an overview about the current research progress,key challenges and future prospects of various types of rechargeable *** computational methods for materials development,and characterization techniques will also be discussed as they play an important role in battery research.

关键词： energy storage rechargeable batteries battery materials electrochemistry

基于RF-LSTM模型的长江上游汛期日含沙量预测

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中国农村水利水电 2024年第10期 32-39页

作者：林天宙彭杨罗诗琦张志鸿华北电力大学水利与水电工程学院北京102206

含沙量预测对流域泥沙治理、水沙调控以及水质与水环境管理等具有重要意义。长江上游地区幅员广阔,支流众多,水沙来源复杂,对准确预测三峡入库含沙量过程构成了挑战。针对长江上游区间降雨和干支流来水来沙对寸滩站含沙量产生不同程度... 详细信息

含沙量预测对流域泥沙治理、水沙调控以及水质与水环境管理等具有重要意义。长江上游地区幅员广阔,支流众多,水沙来源复杂,对准确预测三峡入库含沙量过程构成了挑战。针对长江上游区间降雨和干支流来水来沙对寸滩站含沙量产生不同程度的影响,提出了一种基于随机森林(Random Forest,RF)与长短时记忆(Long Short Term Memory,LSTM)神经网络结合的日含沙量预测深度学习模型RF-LSTM。首先,该模型利用RF算法筛选出与寸滩站日含沙量相关性强的水沙因子,然后将这些因子作为LSTM神经网络的输入变量,进一步识别出优选水沙因子与寸滩含沙量之间的映射关系,最后以长江上游向家坝至寸滩区间为研究区域,应用该模型对不同预见期下的寸滩站汛期日含沙量进行了预测,结果表明:与LSTM模型相比,RF-LSTM模型能较好地考虑预测因子对含沙量影响的滞后效应,且有效捕获与寸滩站日含沙量相关性强的特征,四种预见期下其在预测精度和性能方面均有较好表现,其中无预见期和预见期1 d时两种模型预测精度均较高,验证期的纳什效率系数均大于0.82.无预见期下RF-LSTM模型的纳什效率系数可达到0.91,相应的均方根误差和平均绝对误差分别较LSTM模型降低了13%和8%,且两种预见期下RF-LSTM模型可以较为准确捕获沙峰及峰现时间;当预见期增加至2.d和3 d时两种模型精度均有明显下降,但RF-LSTM模型计算精度仍优于LSTM模型。研究结果可为长江上游含沙量预测提供参考。

关键词：含沙量预测随机森林长短时记忆神经网络长江上游