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Current-carrying tribological behavior of C/Cu contact pairs in extreme temperature and humidity environments for railway catenary systems

第十三届中国科协年会第3分会场-“食品营养与健康”国际研讨会

作者： qiuping chen, xiaoqin wu, lianliang liu, ying zhang, jianfu shen (School of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310029, China )

The potential of extracts from oiltea camellia (℃E) to prevent obesity was investigated using a high-fat diet (HFD) obesity model. In this animal model, male ICR mice were fed a HFD and treated with ℃E or vehicle for 30 days. Oral administration of ℃E suppressed increases in body weight and fat storage. Serum levels of total cholesterol (TC) and triglycerides (TG) decreased in ℃E treatment groups compared to the HFD group, but high-density lipoprotein cholesterol (HDL-C) increased. In addition, the activity of fatty acid synthase (FAS) in animal liver was significantly lower in the ℃E treatment group. Administration of ℃E also inhibited adipogenesis in a dose-dependent manner in 3T3-L1 cells, as seen by Oil Red O staining. Our results suggest that ℃E may be useful in the treatment of obesity and related disorders by acting to prevent weight gain. The metabolic effects of ℃E may be mediated through FAS inhibition.

关键词： Oiltea camellia anti-obesity gallic acid adip℃yte fatty acid synthase

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Science China(Technological Sciences) 2024年第8期67卷 2537-2548页

作者： shen MingXue JI DeHui HU Qiang XIAO Li LI qiuping State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure East China Jiaotong UniversityNanchang 330013China School of Materials Science and Engineering East China Jiaotong UniversityNanchang 330013China Institute of Applied Physics Jiangxi Academy of SciencesNanchang 330095China

Many current-carrying contact pairs, such as those found in pantograph-catenary systems, operate in open environments and are susceptible to significant external interference from temperature and humidity variations. This study investigated the evolution of the friction coefficient and contact resistance of C/Cu contact pairs under alternating temperature, humidity, and current conditions. Through experimentation, the wear rate and microtopography of the worn surface were analyzed under various constant parameters. Subsequently, the differences in tribological behavior and current-carrying characteristics of the contact pairs under these three parameters were explored. The results revealed that the decrease in temperature resulted in a significant increase in the friction coefficient of the contact pairs, carbon wear, and copper surface roughness. Additionally, the surface oxidation rate was lower at lower temperatures. Moreover, contact resistance did not consistently increase with decreasing temperature, owing to the combined action of the contact area and the oxide film. Compared with temperature, humidity fluctuations at room temperature exerted less influence on the friction coefficient and contact resistance of the contact pairs. Dry environments rendered carbon materials vulnerable to oxidation and cracking, while excessive humidity fostered abrasive wear and arcing. High-current conditions generally degraded the tribological properties of C/Cu contacts. In the absence of current, the friction coefficient was extremely high, and the copper transfer was high. Under excessive current, copper was susceptible to plowing by carbon micro-bumps and abrasive particles, resulting in a decrease in the friction coefficient. The release of lipids from the carbon surface due to temperature elevation weakened the electrical contact performance and increased the occurrence of arc erosion, thereby exacerbating carbon wear.

关键词： temperature/humidity pantograph-catenary system C/Cu wear current-carrying friction sliding electrical contact

风力发电机组高强螺栓不同润滑工艺的影响研究

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机械工程师 2024年第7期 75-78,81页

作者：张建福沈锋吴洋特力佳(天津)风电设备零部件有限公司天津300467

针对风力发电机组高强螺栓现有的半涂抹和全涂抹润滑工艺,通过试验测试对比方法分析了在各种工艺下螺栓的转矩系数、稳定性及防松可靠性。结果显示,采取半涂抹工艺润滑时,螺栓转矩系数高,防松性能好,但转矩系数的离散性较大,生产和使用... 详细信息

针对风力发电机组高强螺栓现有的半涂抹和全涂抹润滑工艺,通过试验测试对比方法分析了在各种工艺下螺栓的转矩系数、稳定性及防松可靠性。结果显示,采取半涂抹工艺润滑时,螺栓转矩系数高,防松性能好,但转矩系数的离散性较大,生产和使用过程中都不容易控制,大批量推广时更容易导致螺栓的失效;采用全涂抹工艺润滑时,螺栓转矩系数低,防松性能差,但其转矩系数稳定,标准偏差小,对该工艺进行增加防松垫圈改进后,防松性能有明显改进,更适合大批量应用。该研究对风力发电机组高强螺栓的设计具有参考意义,为高强螺栓的安装使用提供了指导。

关键词：风力发电机组高强螺栓润滑工艺半涂抹全涂抹

Enhancing the elastoplastic damage constitutive model for clayey rocks: Incorporating anisotropy, saturation, time-dependent, and debonding effects

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第9期15卷 2291-2312页

作者： Jueliang chen Siyu liu Wanqing shen jianfu Shao Minh-Ngoc Vu Wenzhou Key Laboratory of Intelligent Lifeline Protection and Emergency Technology for Resilient City College of Architecture and Energy EngineeringWenzhou University of TechnologyWenzhou325000China Department of Civil Engineering Polytech LilleUniversity of LilleLaMcube59000LilleFrance College of Civil Engineering and Transportation HOHAI UniversityNanjingChina Andra 92298Chatenay MalabryFrance

This paper introduced a novel microstructure-based constitutive model designed to comprehensively characterize the intricate mechanical behavior of anisotropic clay rocks under the influence of water *** proposed model encompasses elastoplastic deformation,time-dependent behavior,and induced damage.A two-step homogenization process incorporates mineral compositions and porosity to determine the macroscopic elastic tensor and plastic yield *** model also considers interfacial debonding between the matrix and inclusions to capture rock *** application of the proposed model is demonstrated through an analysis of Callovo-Oxfordian clayey rocks,specifically in the context of radioactive waste disposal in *** parameters are determined,followed by numerical simulations of various laboratory tests including lateral decompression tests with constant mean stress,triaxial compression tests under different water saturation conditions,and creep *** numerical results are compared with corresponding experimental data to assess the efficacy of the proposed model.

关键词： Clayey rocks Micromechanics Anisotropy Plasticity Viscoplasticity Debonding damage Saturation

基于马尔科夫模型的社区人群启动降压药物治疗预防心血管病的策略比较

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北京大学学报（医学版） 2024年第3期56卷 441-447页

作者：周恬静刘秋萍张明露刘晓非康佳丽沈鹏林鸿波唐迅高培北京大学公共卫生学院流行病与卫生统计学系北京100191 宁波市鄞州区疾病预防控制中心浙江宁波315101 重大疾病流行病学教育部重点实验室(北京大学) 北京100191 北京大学临床研究所真实世界证据评价中心北京100191

目的:在中国鄞州电子健康档案研究(Chinese electronic health records research in Yinzhou,CHERRY)的队列人群中,评价启动降压药物治疗的不同策略预防心血管病的健康收益与干预效率。方法:采用马尔科夫模型模拟评价的不同策略包括:策... 详细信息

目的:在中国鄞州电子健康档案研究(Chinese electronic health records research in Yinzhou,CHERRY)的队列人群中,评价启动降压药物治疗的不同策略预防心血管病的健康收益与干预效率。方法:采用马尔科夫模型模拟评价的不同策略包括:策略1,对收缩压≥140 mmHg的人群启动降压药物治疗(根据2020年《中国心血管病一级预防指南》);策略2,对收缩压≥130 mmHg的人群启动降压药物治疗;策略3,对收缩压≥140 mmHg以及130~140 mmHg且心血管病高风险人群启动降压药物治疗(根据2017年美国心脏病学会/美国心脏协会《成年人高血压预防、检测、评估和管理指南》);策略4,对收缩压≥160 mmHg以及140~160 mmHg且心血管病高风险人群启动降压药物治疗(根据2019年英国国家卫生与临床优化研究所《成年人高血压诊断与管理指南》)。采用2019年世界卫生组织心血管病风险评估模型进行风险分层。马尔科夫模型的循环周期设为1年,模拟10个周期后计算质量调整生命年(quality-adjusted life year,QALY)、心血管病发病数、全因死亡数等结局事件数以评价策略的健康收益,并计算每预防一例心血管病事件或全因死亡的需治疗人数(number needed to treat,NNT)以评价策略的干预效率。马尔科夫模型的参数主要来源于CHERRY队列与公开发表的文献。采用单因素敏感性分析探讨心血管病发病率对结果的影响,采用概率敏感性分析探讨干预措施效应参数的不确定性对结果的影响。结果:共纳入213987名35~79岁基线无心血管病史的人群。相比于策略1,单纯下调降压起始值的策略2可预防的心血管病发病数增加666(95%UI:334~975)例,但每预防一例心血管病发病的NNT增加10(95%UI:7~20)人;而考虑定量风险评估的策略3可预防的心血管病发病数增加388(95%UI:194~569)例,且每预防一例心血管病发病的NNT减少6(95%UI:4~12)人,提示策略3可增加健康收益并具有更高的干预效率。策略4相比于策略1,可预防的心血管病发病数虽然减少193(95%UI:98~281)例,但每预防一例心血管病事件的NNT减少18(95%UI:13~37)人,效率更高。单因素敏感性分析及概率敏感性分析结果与主分析结果一致。结论:在中国发达地区的社区人群中选择降压药物治疗目标人群时,结合心血管病定量风险评估的策略优于单纯将起始值从140 mmHg降至130 mmHg的策略,前者可提升健康收益且兼顾干预效率;不同地区需因地制宜选择降压起始值并结合定量风险评估的策略,以权衡健康收益与干预效率。

关键词：心血管病一级预防血压管理马尔科夫模型

CEPC Technical Design Report

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Radiation Detection Technology and Methods 2024年第1期8卷 I0003-I0016,1-1091页

作者： Waleed Abdallah Tiago Carlos Adorno de Freitas Konstantin Afanaciev Shakeel Ahmad Ijaz Ahmed Xiaocong Ai Abid Aleem Wolfgang Altmannshofer Fabio Alves Weiming An Rui An Daniele Paolo Anderle Stefan Antusch Yasuo Arai Andrej Arbuzov Abdesslam Arhrib Mustafa Ashry Sha Bai Yu Bai Yang Bai Vipul Bairathi Csaba Balazs Philip Bambade Yong Ban Tripamo Bandyopadhyay Shou-Shan Bao Desmond P.Barber Ayse Bat Varvara Batozskaya Subash Chandra Behera Alexander Belyaev Michele Bertucci Xiao-Jun Bi Yuanjie Bi Tianjian Bian Fabrizio Bianchi Thomas Biekotter Michela Biglietti Shalva Bilanishvili Deng Binglin Denis Bodrov Anton Bogomyagkov Serge Bondarenko Stewart Boogert Maarten Boonekamp Marcello Borri Angelo Bosotti Vincent Boudry Mohammed Boukidi Igor Boyko Ivanka Bozovic Giuseppe Bozzi Jean-Claude Brient Anastasiia Budzinskaya Masroor Bukhari Vladimir Bytev Giacomo Cacciapaglia Hua Cai Wenyong Cai wujun Cai Yijian Cai Yizhou Cai Yuchen Cai Haiying Cai Huacheng Cai Lorenzo Calibbi Junsong Cang Guofu Cao Jianshe Cao Antoine Chance Xuejun Chang Yue Chang Zhe Chang Xinyuan Chang Wei Chao Auttakit Chatrabhuti Yimin Che Yuzhi Che Bin chen Danping chen Fuqing chen Fusan chen Gang chen Guoming chen Hua-Xing chen Huirun chen Jinhui chen Ji-Yuan chen Kai chen Mali chen Mingjun chen Mingshui chen Ning chen Shanhong chen Shanzhen chen Shao-Long chen Shaomin chen Shiqiang chen Tianlu chen Wei chen Xiang chen Xiaoyu chen Xin chen Xun chen Xurong chen Ye chen ying chen Yukai chen Zelin chen Zilin chen Gang chen Boping chen Chunhui chen Hok Chuen cheng Huajie cheng Shan cheng Tongguang cheng Yunlong Chi Pietro Chimenti Wen Han Chiu Guk Cho Ming-Chung Chu Xiaotong Chu Ziliang Chu Guglielmo Coloretti Andreas Crivellin Hanhua Cui Xiaohao Cui Zhaoyuan Cui Brunella D'Anzi Ling-Yun Dai Xinchen Dai Xuwen Dai Antonio De Maria Nicola De Filippis Christophe De La Taille Francesca De Mori Chiara De Sio Elisa Del Core Shuangxue Deng Wei-Tian Deng Zhi Deng Ziyan Deng Bhupal Dev Tang Dewen Biagio Di Micco Ran Ding Siqin Dingl Yadong Ding Haiyi Dong Jianin AGH University of Science and Technology Faculty of Physics and Applied Computer ScienceKrakow Anhui University HefeiAnhui Applied Physics Department Federal Urdu University of ArtsScience and TechnologyIslamabad Banaras Hindu University Institute of ScienceVaranasi Bandirma Onyedi Eylul University Bandirma Beihang University Beijing Beijing Computational Science Research Center Beijing Beijing Conveyi LTD Beijing Beijing Glass Research Institute Co. LtdBeijing Beijing Institute of Technology Beijing Beijing Normal University Beijing Brown University ProvidenceRI Budker Institute of Nuclear Physics Novosibirsk Cadi Ayyad University Laboratory of Fundamental and Applied PhysicsPolydisciplinary FacultyMarrakech Cairo University Giza Center for Theory and Computation National Tsing Hua UniversityHsinchu Central China Normal University WuhanHubei Central South University ChangshaHunan Centro de Fisica Teorica de Particulas Universidade Tecnica de LisboaLisboa chengdu KaitengSifang Digital Radio&TV Equipment Co. LtdChengduSichuan China academy of engineering physics MianyangSichuan China building materials academy Beijing China Center of Advanced Science and Technology Beijing China Institute of Atomic Energy Beijing China Jiliang University HangzhouZhejiang China Nuclear Instrument CO. LTDBeijing China University of Geosciences Beijing China University of Geosciences WuhanHubei China University of Mining and Technology XuzhouJiangsu China West Normal University NanchongSichuan Chongqing University Department of PhysicsChongqing Chulalongkorn University Bangkok City University of Hong Kong Department of PhysicsHong Kong Cockcroft Institute Daresbury Cornell University IthacaNY CPPM(AMU/IPhU&CNRS/INP) Marseille Dalian Minzu University DalianLiaoning Dalian University of Technology Department of PhysicsDalian Deutsches Elektronen-Synchrotron DESY Hamburg Dzhelepov Laboratory of Nuclear Problems of Joint Institute for Nuclear Research(DLNP JINR) Dubna East China University Of Science And Technol

The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international *** complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs *** its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs *** the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of *** Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering ***,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection *** is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 *** commencement of experiments and data collection could potentially be initiated in the mid-2030s.

关键词： initiated exceeding precise

Construction and application of the Synechocystis ***6803-ftnA in microbial contamination control in a coupled cultivation and wastewater treatment

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Journal of Environmental Sciences 2016年第8期28卷 174-181页

作者： Yalei zhang Chunmin zhang Xuefei Zhou Zheng shen Fangchao Zhao jianfu Zhao State Key Laboratory of Pollution Control and Resource Reuse Key Laboratory of Yangtze Water Environment of Ministry of EducationTongji University Water Conservancy Development Research Center Taihu Basin Authority of Ministry of Water Resources

Inspired by iron fertilization experiments in HNLC（high-nitrate, low-chlorophyll） sea areas,we proposed the use of iron-rich engineered microalgae for microbial contaminant control in iron-free culture media. Based on the genome sequence and natural transformation system of Synechocystis sp. PCC6803, ftn A（encoding ferritin） was selected as our target gene and was cloned into wild-type Synechocystis sp. PCC6803. Tests at the molecular level confirmed the successful construction of the engineered Synechocystis sp. PCC6803-ftn A. After Fe3＋-EDTA pulsing, the intracellular iron content of Synechocystis sp. PCC6803-ftn A was significantly enhanced, and the algae was used in the microbial contamination control system. In the coupled Synechocystis sp. PCC6803-ftn A production and municipal wastewater（MW, including Scenedesmus obliquus and Bacillus） treatment, Synechocystis sp. PCC6803-ftn A accounted for all of the microbial activity and significantly increased from 70% of the microbial community to 95%.These results revealed that while the stored iron in the Synechocystis sp. PCC6803-ftn A cells was used for growth and reproduction of this microalga in the MW, the growth of other microbes was inhibited because of the iron limitation, and these results provide a new method for microbial contamination control during a coupling process.

关键词： Synechocystis PCC6803-ftnA Municipal wastewater treatment Microbial contaminants

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基于RNA检测畜禽病原菌活菌方法研究进展

现代畜牧兽医 2024年第6期 81-85页

作者：沈静怡徐佳瑶陈赵圆刘晓明庄林林申秋平江苏农林职业技术学院江苏镇江212400

致病菌对人类健康和畜牧业发展造成了巨大威胁,因此,快速精准检测具有感染能力的病原菌活菌具有重要的公共卫生学意义。已有研究表明,RNA分子与细胞的代谢活性高度相关,并且会在细菌死亡后迅速降解,因此RNA具有作为活菌分子标志物的应... 详细信息

致病菌对人类健康和畜牧业发展造成了巨大威胁,因此,快速精准检测具有感染能力的病原菌活菌具有重要的公共卫生学意义。已有研究表明,RNA分子与细胞的代谢活性高度相关,并且会在细菌死亡后迅速降解,因此RNA具有作为活菌分子标志物的应用价值。文章对已应用于常见畜禽病原菌活菌检测的RNA分子进行了分类和总结,并讨论了当前相关方法的优缺点和面临的挑战,最后展望了RNA的活菌检测方法未来的发展方向。期待未来能够发掘更多的新靶标并发展更多的新兴技术,为科学防控畜禽病原菌感染及相关传染病的临床诊断提供更多有力工具支持。

关键词：畜禽病原菌活菌检测 RNA 检测方法

考虑渗吸效应的页岩油井体积压裂用液强度优化方法——以南襄盆地泌阳凹陷X-1井为例

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石油勘探与开发 2024年第3期51卷 588-596页

作者：蒋廷学沈子齐王良军齐自立肖博秦秋萍范喜群王勇曲海中国石化页岩油气钻完井及压裂重点实验室北京102206 国家油页岩开采研发中心北京102206 页岩油气富集机理与高效开发全国重点实验室北京102206 中石化石油工程技术研究院有限公司北京102206 中国石化河南油田分公司河南南阳473132 重庆科技大学重庆401331

以南襄盆地泌阳凹陷X-1井为例,将岩心实验测得的带压渗吸规律通过岩心尺度油藏模拟拟合得到表征渗吸过程的毛管压力特征曲线及相对渗透率特征曲线,将其代入宏观油藏模型中模拟压后焖井过程,建立体积压裂用液强度优化方法。研究表明:压... 详细信息

以南襄盆地泌阳凹陷X-1井为例,将岩心实验测得的带压渗吸规律通过岩心尺度油藏模拟拟合得到表征渗吸过程的毛管压力特征曲线及相对渗透率特征曲线,将其代入宏观油藏模型中模拟压后焖井过程,建立体积压裂用液强度优化方法。研究表明:压裂液用液强度的优化必须考虑造缝要满足预测最终可采储量的需求、满足渗吸驱油的需求、满足补充地层能量的需求,同时将压裂液用液强度控制在临界渗吸强度附近,避免液量过少导致渗吸置换作用不充分,液量过大导致成本增加与潜在储层伤害。模拟发现,压裂液用液强度与单井预测最终可采储量正相关且存在最优值,大于最优值后,单井预测最终可采储量增加的幅度将越来越小,通过适当提高压裂液用液强度补充地层能量提高焖井压力,适当增加焖井时间,可有效增加压后产能。经过X-1井现场试验验证,该优化方法对油井生产效果改善显著,具有较好的实用性。

关键词：页岩油水平井体积压裂渗吸效应用液强度参数优化

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新疆大石峡水利枢纽无压泄洪洞衬砌混凝土温控防裂研究

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西北水电 2024年第1期 55-61页

作者：刘利高建福钱国文褚浩羽沈伟刘权赵鑫中国葛洲坝集团市政工程有限公司湖北宜昌443000 新疆维吾尔自治区塔里木河流域大石峡水利枢纽工程建设管理局新疆库尔勒841000 中国电建集团西北勘测设计研究院有限公司西安710065

受高速水流长期冲刷作用的影响,泄洪洞衬砌混凝土一旦产生裂缝,必将引起过流面的空蚀破坏,进而影响工程的正常稳定运行。因此,对泄洪洞衬砌混凝土进行温控防裂研究具有重要意义。依托大石峡水利枢纽泄洪排沙洞工程,采用三维有限元法,计... 详细信息

受高速水流长期冲刷作用的影响,泄洪洞衬砌混凝土一旦产生裂缝,必将引起过流面的空蚀破坏,进而影响工程的正常稳定运行。因此,对泄洪洞衬砌混凝土进行温控防裂研究具有重要意义。依托大石峡水利枢纽泄洪排沙洞工程,采用三维有限元法,计算分析了不同温控措施下泄洪洞衬砌混凝土温度及温度应力的变化规律,论证了不同温控措施的适宜性。结果表明:喷雾洒水措施对改善衬砌混凝土表面温度应力具有一定的效果,并对混凝土干缩裂缝有明显的抑制作用;通水冷却措施主要侧重于改善衬砌混凝土内部的温度和应力状况,但会促使降温过程提前产生,增加早期开裂的风险,因此在施工过程中应严格控制混凝土降温速率和早期降温幅度,建议控制混凝土降温速率不超过2.0~2.5℃/d;施工初期和冬季低温时期均是温度裂缝发生的较危险时段,以冬季保温措施配合施工期的降温措施可以获得更佳的效果。研究成果可为类似泄洪洞工程衬砌混凝土的温控防裂设计与施工提供参考。

关键词：泄洪洞衬砌混凝土温控防裂有限元分析