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Statement on Establishment of Public Health Protection Guideline for Cold Spells—China

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China CDC weekly 2024年第5期6卷 92-94页

作者： Tiantian Li Qinghua Sun Chen Chen Qing Wang Jie Ban Runmei Ma Yi Zhang Lijun Pan Yuanyuan liu Qiutong Li Leyao Chang Hanshuo Zhang yirong liu Miaoyou Niu Xiangxiang Wei Lin Wang China CDC Key Laboratory of Environment and Population Health National Institute of Environmental HealthChinese Center for Disease Control and PreventionBeijingChina

Cold spells are extreme weather events characterized by the invasion of cold air from high latitudes into the middle and low latitudes,resulting in significant *** spells have various adverse health effects,including epidermal damage,respiratory tract spasms,respiratory immune abnormalities,acute cardiopulmonary diseases,and exacerbation of urinary and endocrine *** response to the frequent cold spells in recent years.

关键词： respiratory invasion acute

碳中和目标下中美英绿色生态城区评价标准能源指标的比较与启示

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西部人居环境学刊 2024年第3期39卷 116-122页

作者：王静刘艺蓉冯聃雅华南理工大学建筑学院东南大学建筑学院

面向碳中和目标,我国《绿色生态城区评价标准》具有优化升级的可能,但优化路径有待探索。通过梳理国外绿色生态城区评价标准发现,评价标准整合碳中和目标是趋势所向,能源指标是评价标准优化升级的重点。对此,选择美国LEED Cities and Co... 详细信息

面向碳中和目标,我国《绿色生态城区评价标准》具有优化升级的可能,但优化路径有待探索。通过梳理国外绿色生态城区评价标准发现,评价标准整合碳中和目标是趋势所向,能源指标是评价标准优化升级的重点。对此,选择美国LEED Cities and Communities和英国BREEAM Communities,开展碳中和目标下中美英绿色生态城区评价标准能源指标比较研究。研究表明:美英评价标准能源指标在整合碳中和目标上具有先进性,能源指标分布集中,重视可再生能源与碳排放的评价,且条文细则在“优化能源结构”“注重可再生能源开发”和“建筑与基础设施节能”上已有创新。基于比较结果,对碳中和目标下我国《绿色生态城区评价标准》及其能源指标的优化提出“编制理念及控制项需明确碳中和目标”“调整能源指标的分布情况和分值权重”“能源指标条文细则落位碳中和新技术”3点启示。

关键词：绿色生态城区评价标准碳中和能源指标比较分析

Centers and isochronous centers of a class of quasi-analytic switching systems

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Science China Mathematics 2018年第7期61卷 1201-1218页

作者： Feng Li Pei Yu yirong liu Yuanyuan liu School of Mathematics and Statistics Linyi University Department of Applied Mathematics Western University School of Mathematics and Statistics Central South University

In this paper, we study the integrability and linearization of a class of quadratic quasi-analytic switching systems. We improve an existing method to compute the focus values and periodic constants of quasianalytic switching systems. In particular, with our method, we demonstrate that the dynamical behaviors of quasi-analytic switching systems are more complex than those of continuous quasi-analytic systems, by showing the existence of six and seven limit cycles in the neighborhood of the origin and infinity, respectively, in a quadratic quasi-analytic switching system. Moreover, explicit conditions are obtained for classifying the centers and isochronous centers of the system.

关键词： quasi-analytic switching systems Lyapunov constant limit cycle center isochronous center

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中小型青贮玉米收获机械研究现状及发展趋势

中国农机化学报 2024年第10期45卷 305-310页

作者：段军程方平何成奎刘熠荣王义鹏郭曦达州职业技术学院四川达州635001 四川省农业机械科学研究院成都市610066

随着牛、羊等草食性牲畜的快速发展,畜牧业对青贮玉米饲料的需求持续增长,我国青贮玉米的种植规模也在不断扩大。由于我国耕地类型和地块面积差异较大,青贮玉米的收获需要多种类型的作业机械。为促进玉米青贮收获机械的研发和应用,从畜... 详细信息

随着牛、羊等草食性牲畜的快速发展,畜牧业对青贮玉米饲料的需求持续增长,我国青贮玉米的种植规模也在不断扩大。由于我国耕地类型和地块面积差异较大,青贮玉米的收获需要多种类型的作业机械。为促进玉米青贮收获机械的研发和应用,从畜牧产业适度规模发展的需要和当前我国分段收获与直接收获并存的现实情况出发,采用分作业环节的方式,针对青贮玉米收获机械的共性关键技术:秸秆切割、秸秆切碎揉丝、玉米籽粒破碎、青贮打捆包膜等,分析青贮玉米收获机械生产中的常用结构和最新研究现状。介绍青贮玉米收获机械的研发应用情况,从青贮作业环节中分析总结出存在秸秆切割与粉碎理论研究较少、各装置作业质量研究不足、整机适应性不强等共性问题。提出加强刀具与秸秆互作机理的研究、作业质量的研究、整机适应性的研究,使中小型青贮玉米收获机械在不同规模和作业需求下具有更好的作业性能、作业质量和综合生产效率。

关键词：青贮玉米玉米秸秆仿生切割籽粒破碎秸秆揉丝全株收获

基于空耦冲击回波法的饰面瓷砖层间脱空识别研究

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声学技术 2024年第3期43卷 432-439页

作者：彭强龙士国欧阳德威彭克军李心怡刘昳嵘湘潭大学土木工程学院湖南湘潭411105

针对饰面瓷砖脱空掉落的现象,建立了空气-饰面瓷砖层间脱空有限元模型,分析了钢球半径、激励速度以及信号采集位置等因素对饰面瓷砖层间脱空检测效果的影响,确定了最优值,然后利用特征识别参数对饰面瓷砖粘结层的脱空程度进行评估,并开... 详细信息

针对饰面瓷砖脱空掉落的现象,建立了空气-饰面瓷砖层间脱空有限元模型,分析了钢球半径、激励速度以及信号采集位置等因素对饰面瓷砖层间脱空检测效果的影响,确定了最优值,然后利用特征识别参数对饰面瓷砖粘结层的脱空程度进行评估,并开展足尺试验对有限元模型的有效性进行验证。结果表明:钢球半径建议取9 mm,激励速度建议取1 m·s^(-1),信号采集点与激励点的横向距离不宜小于60 mm,垂向距离取5 mm;黏结层脱空会使冲击回波信号加强。因此,时域图中的信号波动性增强、衰减速度减缓,频域图中的声压级增大,主频段前移并分化为代表结构整体振动和局部振动的两个频段;并且随着脱空程度的增加,频域面积增大,通过计算频域面积可有效评估饰面瓷砖黏结层的脱空状况。研究结果为饰面瓷砖的无损检测提供了参考。

关键词：饰面瓷砖脱空识别空气耦合冲击回波频域面积

Seeking Health Information Online:The Moderating Effects of Problematic Situations on User Intention

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Journal of Data and Information Science 2017年第2期2卷 76-95页

作者： Lidan Xia Shengli Deng yirong liu School of Information Management Wuhan UniversityWuhan 430072China

Purpose： This study investigates how online user intention in searching health information is affected by problematic ***/methodology/approach： Based on the Theory of Reasoned Action, the Technology Acceptance Model, and Sense-making theory, we propose two dimensions of problematic situations： urgency and severity of health issues being searched online. Data were collected through a questionnaire survey among 214 Wuhan University students and analyzed using hierarchical regression ***： Perceived usefulness, perceived ease of use, and subjective norm can influence user intention to seek health information online. The urgency of problematic situations has a negative moderating effect on the relationship between perceived ease of use and user intention and the relationship between subjective norm and user intention. The severity of problematic situations has a negative moderating effect on the relationship between subjective norm and user *** limitations： The respondents of the survey are limited to students in one Chinese university, so whether this study＇s results can be applied to another population or not remains to be verified. In addition, only two dimensions of problematic situations are considered in this study. Practical implications： The paper puts forward the moderating effect of problematic situations and verifies it, which is the compensation for online health information-seeking behavior research. Besides, our analyses have implications for professional design of health care systems and related consumer information searches, and improve their performance. Originality/value： Previous work has reported the effects of problematic situation on user intention to seek health information online, ignoring its influence on other factors. This empirical study extends that work to identify the influence of problematic situation when seeking intention-behavior data in two dimensions, urgency and severity.

关键词： Health information seeking Situation Moderating effect Urgency Severity

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5G消息业务发展现状及关键问题分析

长江信息通信 2024年第6期37卷 217-220页

作者：王若臣张大元刘一蓉曹茜刘平平中国信息通信研究院泰尔系统实验室北京100191

5G消息业务通过升级原生短消息入口,向用户提供更为便捷、丰富的即时消息新服务,这是电信运营商创新业务模式、探索更多应用场景的重要尝试。文章总结了5G消息业务在政策支持、标准化、产业发展等三方面的现状,并深入分析了在计费模式... 详细信息

5G消息业务通过升级原生短消息入口,向用户提供更为便捷、丰富的即时消息新服务,这是电信运营商创新业务模式、探索更多应用场景的重要尝试。文章总结了5G消息业务在政策支持、标准化、产业发展等三方面的现状,并深入分析了在计费模式、互联互通、安全及感知等方面制约5G消息产业发展的关键问题,为5G消息业务高质量发展指明方向。

关键词： 5G消息计费模式用户感知

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LNG接收站回收乙烷的工艺流程分析

石油工程建设 2024年第3期50卷 35-41,72页

作者：贾保印刘峰刘以荣戚家明胡本源庄芳中国寰球工程有限公司北京100012 昆仑能源有限公司北京100101

从LNG接收站中分离出乙烷及其他轻烃不但可以避免与下游燃气产生互换性问题,还能为下游石油化工提供乙烷原料,可获得额外的经济效益。依托LNG接收站的实际运行维护情况,开展从LNG接收站中分离乙烷的方案研究,并从原料稳定性、能耗、电... 详细信息

从LNG接收站中分离出乙烷及其他轻烃不但可以避免与下游燃气产生互换性问题,还能为下游石油化工提供乙烷原料,可获得额外的经济效益。依托LNG接收站的实际运行维护情况,开展从LNG接收站中分离乙烷的方案研究,并从原料稳定性、能耗、电气化率、安全泄放、冷能利用等方面对比气体分离和液体分离2种工艺流程。研究表明:液相分离工艺具有原料操作温度和压力波动性小、无需天然气增压、自用自身冷量、负荷调节范围广、就地取材利用环境热源、乙烷回收率高等特点,同时对LNG接收站外输波动规律的匹配性强;此外,LNG接收站开展乙烷回收对天然气管网安全运行、提升LNG接收站经济效益、冷热能量综合利用,以及上下游一体化发展,具有十分重要的意义。

关键词： LNG接收站分离乙烷自身冷量回收率膨胀机

Regularly Tuning Quantum Interference in Single-Molecule Junctions through Systematic Substitution of Side Groups with Varied Electron Effects

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Chinese Journal of Chemistry 2024年第11期42卷 1217-1222页

作者： Xianjing Xie yirong Zhang Junrui Zhang Xingyuan Cui Wei liu Xunshan liu Key Laboratory of Surface&Interface Science of Polymer Materials of Zhejiang Province School of Chemistry and Chemical EngineeringZhejiang Sci-Tech University928 Second StreetHangzhouZhejiang310018 China State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchunJilin130022 China School of Materials Science and Engineering Nanjing University of Science and TechnologyNanjingJiangsu210094 China

Investigating the quantum interference effect in single molecules is essential to comprehensively understand the underlying mechanism of single-molecule charge *** this study,we employed the mother molecule m-OPE and introduced a series of side groups with various electronic effects at the 2-position of the central phenyl ring,creating four daughter m-OPE *** single molecular conductivities of these molecule wires were measured using the scanning tunneling microscope breaking junction *** findings demonstrate that the substitutions regularly modulate the destructive quantum interference occurring within the m-OPE *** combining optical and electrochemical investigations,along with density functional theory computations,we discover that the conductivity of the molecules corresponds to the electron-donating/withdrawing ability of the ***,by adjusting the electron structures of the molecular backbone,we can systematically tailor the destructive quantum interference in the m-OPE molecules.

关键词： Quantum interference Single-molecule junctions Electron effect substituents Charge transport Molecular devices