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A review of dual-spin projectile stability

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Defence Technology（防务技术） 2020年第1期16卷 1-9页

作者： James Norris Amer Hameed john Economou simon Parker Centre for Defence Engineering Cranfield UniversityDefence Academy of the United KingdomShrivenhamSN68LA United Kingdom BAE Systems United Kingdom

This paper gives a succinct review of dual-spinprojectile stability and some technologies relating to *** describes how the traditional stability factors from linear projectile theory are modified to better describe a controlled dual-spin ***,it reviews works which have investigated how different aspects of a controlled dual-spin design can affect flight stability,primarily airframe structure and canard properties.A conclusion is given,highlighting important guidelines from the enclosed discussions.

关键词： Guided projectiles Dual-spin Gyroscopic Dynamic Stability Canards

New dating indicates intermittent human occupation of the Nwya Devu Paleolithic site on the high-altitude central Tibetan Plateau during the past 45,000 years

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Science China Earth Sciences 2024年第2期67卷 531-551页

作者： Junyi GE Xiaoling ZHANG Shejiang WANG Linhui LI Wei HE Yingshuai JIN Peiqi ZhANG Bing XU Chenglong DENG john WOLSEN Zhengtang GUO Xing GAO Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of SciencesBeijing 100044China University of the Chinese Academy of Sciences Beijing 100049China Tibetan Cultural Relics Conservation Institute Lhasa 850000China Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of Sciences.Beijing 100029China State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China School of Anthropology University of ArizonaTucson85721USA

The timing and mechanisms of the human occupation of the demanding high-altitude Tibetan Plateau environment are of great ***,we report on our reinvestigations and dating of the Nwya Devu site,located nearly 4600 meters above sea level on the central Tibetan Plateau.A new microblade techno-complex was identified on a lower lake shore at this site,distinct from the previously reported blade tool *** two lithic assemblages were dated to 45.6±2.6 and10.3±0.5 ka using optically stimulated luminescence and accelerator mass spectrometry^(14)C *** represent,respectively,the earliest known Paleolithic and microlithic sites on the interior Tibetan Plateau,indicating multiple occupation episodes of hunter-gatherers during the past 45 *** studies reveal that relatively stable depositional conditions and a paleoenvironment characterized by a comparatively warm climate facilitated these multiple occupations at Nwya *** contemporaneous occurrence of the Upper Paleolithic blade technology on the Tibetan Plateau and most of Eurasia between 50 and 40 ka indicates rapid,large-scale dispersals of humans that profoundly affected human demography on a large *** new archaeological evidence and previously reported genetic data,we conclude that the Tibetan Plateau provided a relatively stable habitat for Upper Paleolithic hunter-gatherers,which may have contributed to the complex and multiple-origin gene pool of present-day Tibetans.

关键词： Tibetan Plateau Paleolithic Nwya Devu High-altitude adaptation Microblade industry Early Upper Paleolithic OSLdating AMS^(14)C dating

Adaptive strategies of high and low nucleic acid prokaryotes in response to declining resource availability and selective grazing by protozoa

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Science China Earth Sciences 2024年第6期67卷 1872-1884页

作者： Chen HU Liuqian YU Xiaowei CHEN Jihua LIU Yao ZHANG john BATT Xilin XIAO Qiang SHI Rui ZHANG Tingwei LUO Nianzhi JIAO Dapeng XU College of the Environment and Ecology Xiamen UniversityXiamen 361102China State Key Laboratory of Marine Environmental Science College of Ocean and Earth SciencesFujian Key Laboratory of Marine Carbon SequestrationXiamen UniversityXiamen 361102China Joint Lab for Ocean Research and Education(LORE)of Dalhousie University Canadaand Shandong University and Xiamen UniversityXiamen 361102China Earth Ocean and Atmospheric Sciences ThrustThe Hong Kong University of Science and Technology(Guangzhou)Guangzhou 510000China Institute of Marine Science and Technology Shandong UniversityQingdao 266237China Department of Oceanography Dalhousie UniversityHalifaxNova Scotia B3H 4R2Canada Institute for Advanced Study Shenzhen UniversityShenzhen 518060China Carbon Neutral Innovation Research Center Xiamen UniversityXiamen 361102China

Prokaryotes play a fundamental role in global ocean biogeochemical ***,how the abundance and metabolic activity of ecologically distinct subgroups(i.e.,high nucleic acid(HNA)and low nucleic acid(LNA)cells),and their regulating factors,change in response to changing marine environmental conditions remains poorly ***,we delved into the time-evolving dynamic responses of the HNA and LNA prokaryotic subgroups to declining resource availability and selective grazing by protozoa by conducting a 73-day incubation experiment in a large-volume(117,000 L)macrocosm that facilitates community-level *** found that the metabolic activity of the HNA subgroup was higher than that of the LNA subgroup when the macrocosm was resource replete but that the HNA subgroup declined more rapidly than the LNA subgroup as the resources became increasingly scarce,leading to a steadily increasing contribution of LNA cells to prokaryotic ***,as resources in the macrocosm became limited,protozoan grazing preference shifted from the HNA to the LNA subgroup and the contributions of the LNA subgroup to the carbon flow within the macrocosm *** findings highlight the resilience of LNA cells in resource-limited environments,illuminate the critical role of selective grazing by protozoa in balancing distinct prokaryotic subgroups under changing resource conditions,and demonstrate the complex and adaptive interactions between protozoa and prokaryotes across diverse environmental contexts.

关键词： Microbial loop Macrocosm experiment Prokaryote Top-down and bottom-up controls Carbon flow

Adverse events related to physical restraint use in intensive care units: A review of the literature

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Journal of Intensive Medicine 2024年第3期4卷 318-325页

作者： Sebastian Berger Pascale Grzonka simon A.Amacher Sabina Hunziker Anja I.Frei Raoul Sutter Clinic for Intensive Care Department of Acute MedicineUniversity Hospital BaselBaselSwitzerland Medical Communication and Psychosomatic Medicine University Hospital BaselBaselSwitzerland Medical faculty University of BaselBaselSwitzerland Department of Clinical Research University of BaselBaselSwitzerland

Physical restraints are widely used and accepted as protective measures during treatment in intensive care unit (ICU). This review of the literature summarizes the adverse events and outcomes associated with physical restraint use, and the risk factors associated with their use during treatment in the ICU. The PubMed, Scopus, and Google Scholar databases were screened using predefined search terms to identify studies pertaining to adverse events and/or outcomes associated with physical restraint use, and the factors associated with their use in adult patients admitted to the ICU. A total of 24 articles (including 6126 patients) that were published between 2006 and 2022 were identified. The described adverse events associated with physical restraint use included skin injuries, subsequent delirium, neurofunctional impairment, and a higher rate of post-traumatic stress disorder. Subsequent delirium was the most frequent adverse event to be reported. No alternative measures to physical restraints were discussed, and only one study reported a standardized protocol for their use. Although physical restraint use has been reported to be associated with adverse events (including neurofunctional impairment) in the literature, the available evidence is limited. Although causality cannot be confirmed, a definite association appears to exist. Our findings suggest that it is essential to improve awareness regarding their adverse impact and optimize approaches for their detection, management, and prevention using protocols or checklists.

关键词： Physical restraint Intensive care unit Delirium Complication Adverse event

Solid-state Circuit Breaker Based on Cascaded Normally-on SiC JFETs for Medium-voltage DC Distribution Networks

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Protection and Control of Modern Power Systems 2024年第2期9卷 32-46页

作者： Dong He Haohui Zhou Zheng Lan Wei Wang Jinhui Zeng Xueping Yu Z.john Shen Chongqing University of Posts and Telecommunications ChongqingChina Henan Polytechnic University JiaozuoChina College of Electrical and Information Engineering Hunan University of TechnologyZhuzhou 412007China Hunan University ChangshaChina College of Electrical and Information Engineering Hunan UniversityChangshaChina College of Electrical Engineering Three Gorges University Rensselaer Polytechnic Institute TroyNYUSA

Solid-state circuit breakers(SSCBs)are critical components in the protection of medium-voltage DC distribution networks to facilitate arc-free,fast and reliable isolation of DC ***,limited by the capacity of a single semiconductor device,using semi-conductor-based SSCBs at high voltage is *** study presents the details of a 1.5 kV,63 A medi-um-voltage SSCB,composed primarily of a solid-state switch based on three cascaded normally-on silicon car-bide(SiC)junction field-effect transistors(JFETs)and a low-cost programmable gate drive *** and static voltage sharing among the cascaded SiC JFETs of the SSCB during fault isolation is realized using the pro-posed gate drive *** selection conditions for the key parameters of the SSCB gate driver are also ***,an improved pulse-width modulation cur-rent-limiting protection solution is proposed to identify the permanent overcurrent and transient inrush current associated with capacitive load startup in a DC distribu-tion *** the developed SSCB prototype and the fault test system,experimental results are obtained to validate the fault response performance of the *** Terms—Solid-state circuit breaker,DC distribu-tion network,SiC JFET,voltage balancing,inrush current.

关键词： Solid-state circuit breaker DC distribu-tion network SiC JFET voltage balancing inrush current

Metal-metal bonds in Zintl clusters:Synthesis,structure and bonding in[Fe_(2)Sn_(4)Bi_(8)]^(3-)and[Cr_(2)Sb_(12)]^(3-)

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Chinese Chemical Letters 2024年第8期35卷 558-566页

作者： Ya-Nan Yang Zi-Sheng Li Sourav Mondal Lei Qiao Cui-Cui Wang Wen-Juan Tian Zhong-Ming Sun john E.McGrady State Key Laboratory of Element-Organic Chemistry Tianjin Key Lab for Rare Earth Materials and ApplicationsSchool of Materials Science and EngineeringNankai UniversityTianjin 300350China Department of Chemistry University of OxfordInorganic Chemistry LaboratoryOxfordOX13QRUnited Kingdom

We report here the synthesis and characterization of two new members of the M2 E 12 family of endohe-dral Zintl clusters,[Fe_(2)Sn_(4)Bi_(8)]^(3-)and[Cr_(2)Sb_(12)]^(3-),both of which contain open-shell metal dimers encap-sulated inside a triple-decker cluster of main-group *** 75-electron[Fe_(2)Sn_(4)Bi_(8)]^(3-)cluster has a D4h-symmetric structure,while[Cr_(2)Sb_(12)]^(3-),despite having the same 75-electron count,is strongly dis-torted to a geometry that resembles a CrSb_(8)crown capped by a CrSb_(4)*** structural differences between the two are driven by the increasing availability of 3d electron density in the earlier transi-tion metal,which leads,ultimately,to different electronic configurations in the two *** trends precisely mirror those observed in the ME_(10)and ME_(12)families containing a single transition metal ion.

关键词： Zintl anions Endohedral clusters Metal-metal bond Second-order Jahn-Teller effect DFT calculation

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气候紧急状况与高等教育

清华大学教育研究 2024年第1期45卷 6-16,49页

作者：西蒙·马金森赵琳(译) 牛津大学教育系美国清华大学教育研究院北京100084

气候紧急状况是一场生存危机,迫切需要人们从根本上改变社会经济发展的主导模式。在竞争性积累和过度消费造成的破坏中,当务之急是建立一种可持续的道德秩序,体现建设性的人与自然的关系以及人与人的关系。按照涂尔干的观点,道德秩序的... 详细信息

气候紧急状况是一场生存危机,迫切需要人们从根本上改变社会经济发展的主导模式。在竞争性积累和过度消费造成的破坏中,当务之急是建立一种可持续的道德秩序,体现建设性的人与自然的关系以及人与人的关系。按照涂尔干的观点,道德秩序的主要组成部分是国家和个人:国家是集体利益的重要保障,个人则负责自我完善和实现社会价值。气候紧急状况突显了世界各国的能力,既要在中央层面有效组织,又要对地方机构下放权力,使其能够有效解决地区问题和灾害。高等教育机构与政府合作,在以下方面发挥着核心作用:推进和捍卫科学,提升治理的知识和技能,培养在地方、社区、国家、区域和全球范围内有效开展社会行动的反思性主体。气候紧急状况还呼唤对课程进行全面改革,使其符合生态生存的要求。高等教育具有先进的跨国合作能力,可以助力民族国家推进稳定的全球合作进程,这一合作进程充满困难却至关重要。在解决这些问题方面,中国和中国的高等教育具有强大的内生传统,包括古代传统和近代传统。这些传统包括中华民族的共识作用,其在有效运用时可以获得广泛的公众支持;在中央政策框架内进行深度权力下放的治理方式;儒家文化所倡导的修身,能够培养出具有自我反思能力的终身学习者;以及“天下”的观念——一种基于道德价值观和行为规范而非强制的全球合作方法。如果再结合西方所尊崇的个人自由和主动性,上述特质在中国乃至全世界应对气候紧急状况方面都将大有可为。

关键词：气候紧急状况生态过度消费政府权力下放高等教育儒家思想科学

Molar ratio induced crystal transformation from coordination complex to coordination polymers

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Chinese Chemical Letters 2024年第4期35卷 539-543页

作者： Peng Meng Qian-Cheng Luo Aidan Brock Xiaodong Wang Mahboobeh Shahbazi Aaron Micallef john McMurtrie Dongchen Qi Yan-Zhen Zheng Jingsan Xu School of Chemistry and Physics&Centre for Materials Science Queensland University of TechnologyBrisbaneQLD 4000Australia Frontier Institute of Science and Technology Xi'an Jiaotong UniversityXi'an 710054China Central Analytical Research Facility Institute for Future EnvironmentsQueensland University of TechnologyBrisbaneQLD 4000Australia

Coordination complex of a copper cyanurate(Cu(Ⅱ)-CA) was transformed into coordination polymers upon the stimulus of extra Cu(Ⅱ) through “directed Ostwald ripening”. By increasing the molar ratio of Cu(Ⅱ) to CA, we obtained two coordination polymers with selective coordination sites: Cu(Ⅱ)-κ N(HCA)κ NCu(Ⅱ) and Cu(Ⅱ)-κ N(HCA)κ O-Cu(Ⅱ), which display disparate magnetic interactions.

关键词： Molar ratio dependent crystal transformation Copper cyanurate Ostwald ripening Molecular magnetism One-dimensional chain

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库普斯墨赫美术馆扩建

世界建筑导报 2024年第3期39卷 100-103页

作者： simon Menges(摄) 不详

2008年,为容纳迄今为止最广泛的德国战后艺术的私人收藏--斯多赫收藏系列,库普斯墨赫美术馆(MKM)提出的扩建项目被提上日程。2013年,扩建项目在斯多赫家族的牵头下启动。赫尔佐格和德梅隆建筑事务受委托对当前条件下该场地的潜力进行了... 详细信息

2008年,为容纳迄今为止最广泛的德国战后艺术的私人收藏--斯多赫收藏系列,库普斯墨赫美术馆(MKM)提出的扩建项目被提上日程。2013年,扩建项目在斯多赫家族的牵头下启动。赫尔佐格和德梅隆建筑事务受委托对当前条件下该场地的潜力进行了可行性研究,他们的成果将会带给扩建项目一个全新的开始。最初的扩建思路是在筒仓塔顶建造一个发光的立方体,使之于远处可见,现在被彻底抛弃了。取而代之的是,建立一座全新建筑,其材料和尺度依据码头沿岸的历史建筑砖块结构来呈现。新建部分以适宜得体的方式融入了码头建筑群,使既有的美术馆综合体成为了一个和谐优美的整体。乍一看,似乎新建筑一直都坐落在那里。

关键词：扩建项目私人收藏可行性研究美术馆多赫