检索结果-南通市图书馆

Journal of Ocean University of China 2023年第6期22卷 1692-1701页

作者： HUO Siyue LIU Wenjie zhao changkun LU Shuailing WANGQianzhi SHE Zonglian zhao Yangguo ZHANG Zhiming GUO liang JI Junyuan JIN Chunji GAO Mengchun Key Lab of Marine Environment and Ecology Ministry of EducationOcean University of ChinaQingdao 266100China Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Qingdao 266061China College of Environmental Science and Engineering Ocean University of ChinaQingdao 266100China

The impact of dissolved oxygen(DO)at aerobic phase on the nitrogen removal,extracellular polymeric substances(EPS),microbial activity and microbial community of sequencing batch biofilm reactor(SBBR)have been evaluated in treating mariculture wastewater.The oxygen uptake rate and nitrification rate declined with DO concentration from 3–4 to 1–1.5mgL^(-1),whereas the denitrification rate had an increment.The activities of nitrifying enzymes reduced with the decrease of DO concentration at aerobic phase,but those of denitrifying enzymes illustrated opposite results.The nitrification and denitrification rates displayed the similar variation tendency with the relevant enzymatic activities as DO concentration decreased.The protein(PN)and polysaccharide(PS)content in EPS decreased as DO concentration declined,whereas the PN/PS ratio increased.The microbial community showed obvious difference as DO concentration decreased from 3–4 to 1–1.5mgL^(-1).The microbial co-occurrence,keystone taxa and sig-nificant difference illustrated some variations at different DO concentrations.

关键词： SBBR mariculture wastewater DO concentration microbial activity microbial community

Opportunities and challenges of organic flow battery for electrochemical energy storage technology

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2022年第4期31卷 621-639页

作者： Ziming zhao changkun Zhang Xianfeng Li Division of Energy Storage Dalian National Laboratory for Clean EnergyDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina Changchun Institute of Applied Chemistry Chinese Academy of SciencesChangchun 130022JilinChina University of Science and Technology of China Hefei 230026AnhuiChina

For flow batteries(FBs), the current technologies are still expensive and have relatively low energy density, which limits their large-scale applications. Organic FBs(OFBs) which employ organic molecules as redox-active materials have been considered as one of the promising technologies for achieving lowcost and high-performance. Herein, we present a critical overview of the progress on the OFBs, including the design principles of key components(redox-active molecules, membranes, and electrodes) and the latest achievement in both aqueous and nonaqueous systems. Finally, future directions in explorations of the high-performance OFB for electrochemical energy storage are also highlighted.

关键词： Electrochemical energy storage Flow battery Organic systems Organic redox-active molecules

A comprehensive multi‐hazard risk assessment model for an urban agglomeration with multiple factors

在线全文

学校读者我要写书评

暂无评论

Journal of Safety Science and Resilience 2023年第1期4卷 43-51页

作者： changkun Chen Dongyue zhao Fan He Fenglin Sun Institute of Disaster Prevention Science and Safety Technology Central South UniversityChangsha 410075China Anhui University of Science and Technology Huainan 232001China

To assist the Department of Emergency Management in understanding the overall risk characteristics and situation of an urban agglomeration for a reasonable risk prevention and control strategy,this study developed a comprehensive multi-hazard risk assessment model for an urban agglomeration with multiple factors.The proposed model includes disaster probability and disaster loss sub-models.The model evaluated four types of disaster risk in urban agglomerations:natural disasters,accidental disasters,public health incidents,and social security incidents.In addition,a variety of factors were integrated into the model,including the socioeconomic foundation of urban agglomerations,the oligopoly effect of core cities,historical disaster losses,the effect of disaster chains,the ability of disaster prevention and mitigation,and intercity coordinated rescue capabilities.Finally,the risk assessment model was applied to the Beijing-Tianjin-Hebei urban agglomeration.The assessment results were compared to the distribution of the new coronavirus pneumonia epidemic in the target urban agglomeration.The results showed that after analyzing the risk characteristics and evaluating the risk levels,the model not only showed the comprehensive risk levels and distribution of urban agglomerations but also revealed the high-risk areas and the key points of risk prevention and control.More importantly,the results obtained through the model can facilitate the strategic planning of disaster prevention and mitigation for urban agglomerations.

关键词： Urban agglomeration Risk assessment Multi-hazard Multifactor Risk prevention and control

Rh(Ⅰ)-catalyzed regio-and enantioselective allylic alkylation of Meldrum's acid

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2021年第1期32卷 385-388页

作者： Min Liu Haiying zhao changkun Li Inner Mongolia Key Laboratory of Fine Organic Syrthesis Cllge of Chemistry and Chemical Enginpering Inner Mongolia UniversityHohhor 010021China Shanghai Key Laboratory for Molcular Engineering of Chirnl Drugs School of Chemistry and Chermical Engineering Shanghai Jiao Tong UiversitShanghai 200240China

A Rh(Ⅰ)-catalyzed highly regio-and enantioselective allylic alkylation of Meldrum acid with racemic allylic substrates bearing alkyl groups has been developed.The applying of chiral bisoxazopinephosphine ligand is essential for the high yields and selectivities.This method provides a rapid access to various chiral β-alkyl-γ,δ-unsaturated carboxylic acids and their derivatives.

关键词： Rhodium Bisoxazolinephosphine Allylic substitution Meldrum’s acid Asymmetric catalysis

黄河上游特有鱼类国家级水产种质资源保护区若尔盖段水生生物资源现状研究

在线全文

学校读者我要写书评

暂无评论

四川师范大学学报（自然科学版） 2024年第4期47卷 507-516页

作者：梅燕陈登胡杰金利李宇浩赵甜梦樊海灵宗浩付长坤四川师范大学生命科学学院四川成都610101 辽宁大学环境学院辽宁沈阳110036 成都碧水长浩生物科技研究所四川成都610100 中国科学院昆明动物研究所云南昆明650201 四川师范大学西南土地资源评价与监测教育部重点实验室四川成都610066

2021年8—9月对黄河上游特有鱼类国家级水产种质资源保护区若尔盖段(核心区)的水生生物资源及其分布实地调查的结果表明,调查河段浮游植物5门29科51属68种,硅藻门(Bacillariophyta)最多,有12科19属32种,占种类总数的47.06%;浮游动物共计... 详细信息

2021年8—9月对黄河上游特有鱼类国家级水产种质资源保护区若尔盖段(核心区)的水生生物资源及其分布实地调查的结果表明,调查河段浮游植物5门29科51属68种,硅藻门(Bacillariophyta)最多,有12科19属32种,占种类总数的47.06%;浮游动物共计2类16种,原生动物和轮虫各占50%;底栖动物共有3门12种,其中节肢动物门种类数最多,占种类总数83.3%;鱼类共计11种,隶属于1目2科6属,其中鳅科(Cobitidae)有1属6种,占总种数的54.55%,鲤科(Cyprinidae)5属5种,占总种数的45.45%.鱼类生态类型以流水底层生态类群为主,按鱼类繁殖习性,鱼类产卵类型主要是产沉性卵和黏性卵;按食性划分,以水生无脊椎动物和藻类为食的鱼类最多;按区系划分,调查河段鱼类区系组成为中亚高山复合体,具有黄河上游区系组成特点.从渔获物组成上分析,占据数量优势有花斑裸鲤(Gymnocypris eckloni)、斯氏高原鳅(Triplophysa stoliczkai)和拟硬刺高原鳅(Triplophysa pseudoscleroptera)占优势,数量占比分别23.08%、21.15%和19.23%.

关键词：黄河上游水产种质保护区水生生物鱼类

维普期刊数据库博看期刊

Cross-sectional rainfall observation on the central-western Tibetan Plateau in the warm season:System design and preliminary results

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2023年第5期66卷 1015-1030页

作者： Kun YANG Yingying CHEN Lazhu Changhui ZHAN Xiaoyan LING Xu ZHOU Yaozhi JIANG Xiangnan YAO Hui LU Xiaogang MA Lin OUYANG Weihao PAN Yanghang REN changkun SHAO Jiaxin TIAN Yan WANG Hua YANG Siyu YUE Ke ZHANG Dingchi zhao Long zhao Jianhong ZHOU Mijun ZOU Ministry of Education Key Laboratory for Earth System Modeling Department of Earth System ScienceInstitute for Global Change StudiesTsinghua UniversityBeijing100084China National Tibetan Plateau Data Center State Key Laboratory of Tibetan Plateau Earth System and Resource EnvironmentInstitute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing100101China Research Center for Ecology College of ScienceTibet UniversityLhasa850011China Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Science and Natural Resources ResearchChinese Academy of SciencesBeijing100101China Chongqing Jinfo Mountain Karst Ecosystem National Observation and Research Station School of Geographical SciencesSouthwest UniversityChongqing400715China

The central and western Tibetan Plateau(CWTP)is characterized by harsh environment and strong interactions among the spheres of earth as well as significant changes in climate and water cycles over the past four decades.The lack of precipitation observations is a bottleneck for the study of land surface processes in this region.Over the past six years,we have designed and established two observation transects across the south-north and the west-east in this region to obtain hourly rainfall data during the warm season(May-September).The south-north transect extends from Yadong Valley on the southern slope of the Himalayas to Shuanghu County in the hinterland of the plateau,with a total of 31stations;the west-east transect extends from Shiquanhe in the west to Naqu in the central TP,with a total of 22 stations.The observation dataset has been applied to clarify the spatiotemporal characteristics of precipitation in the CWTP,to evaluate the quality of typical gridded precipitation products,to support the development of regional climate models,and to reveal the processes of summertime lake-air interactions.The observation dataset has been released in the National Tibetan Plateau Data Center.

关键词： Central and western Tibetan Plateau Rainfall observation transects Observation uncertainty Spatiotemporal characteristics of precipitation Precipitation data evaluation

管道类结构中障碍物阻塞比对可燃液体蒸气爆燃特性的影响

在线全文

学校读者我要写书评

暂无评论

中南大学学报（自然科学版） 2022年第7期53卷 2746-2755页

作者：陈长坤张宇伦赵小龙中南大学土木工程学院湖南长沙410075 清华大学合肥公共安全研究院灾害环境人员安全安徽省重点实验室安徽合肥230601 合肥泽众城市智能科技有限公司安徽合肥230601

为探究可燃液体蒸发扩散诱导的非均匀蒸气浓度分布下障碍物阻塞比对管道类结构爆燃特性影响,利用矩形截面管道模型开展爆燃实验。采用高速摄像机和压力传感器测量并记录爆燃火焰和压强的传播过程。在障碍物宽高比固定的条件下,研究阻塞... 详细信息

为探究可燃液体蒸发扩散诱导的非均匀蒸气浓度分布下障碍物阻塞比对管道类结构爆燃特性影响,利用矩形截面管道模型开展爆燃实验。采用高速摄像机和压力传感器测量并记录爆燃火焰和压强的传播过程。在障碍物宽高比固定的条件下,研究阻塞比对火焰传播速度、压强和出口位置CO体积分数等的影响。研究结果表明:障碍物边缘对火焰前沿的剪切作用能够在一定程度上促使火焰传播加速。火焰传播速度随阻塞比增大而先增大后减小,最大传播速度为97.5 m/s。爆燃压强的变化趋势与火焰传播速度的类似,当达到当前实验条件下的临界阻塞比0.40时,爆燃压强达到峰值。最大压强和爆炸威力指数均表现出随障碍物阻塞比增大而先增大后减小的趋势。此外,管道结构洞口处CO体积分数随阻塞比增大而呈单调增大趋势,最高CO体积分数达到730×10^(-6)。

关键词：狭长管道类结构蒸气爆燃阻塞比火焰传播速度爆燃压强

纵向通风下分岔隧道火灾烟气蔓延特性及控制实验研究

在线全文

学校读者我要写书评

暂无评论

铁道科学与工程学报 2022年第7期19卷 2117-2124页

作者：雷鹏陈长坤赵冬月中南大学防灾科学与安全技术研究所湖南长沙410075

使用1/10的分岔隧道模型开展缩尺寸实验研究,测量不同火源功率和不同纵向通风风速下隧道内纵向温度分布,定性分析隧道火灾发生时热烟气卷吸空气的机制。结果表明:热烟气卷吸空气的根源在于其自身的斜压性和黏性造成的速度剪切。空气卷... 详细信息

使用1/10的分岔隧道模型开展缩尺寸实验研究,测量不同火源功率和不同纵向通风风速下隧道内纵向温度分布,定性分析隧道火灾发生时热烟气卷吸空气的机制。结果表明:热烟气卷吸空气的根源在于其自身的斜压性和黏性造成的速度剪切。空气卷吸直接影响了隧道顶棚下方最大温度和烟气的流动状态。当无量纲通风风速小于0.19时,相比于单管隧道,分岔隧道内火羽流能够卷吸到更多的冷空气,因此顶棚下方最大温度比单管隧道的低;当无量纲通风风速大于0.19时,热烟气较多地被吹向下游,热量分配形式近似与单管隧道,因此顶棚下方最大温度接近单管隧道。随着通风风速的增加,空气卷吸强度增加,烟气层分层现象不明显。分岔隧道中一部分纵向通风风流能够进入支路隧道,因此其临界风速较单管隧道高。提出了适用于本文考虑的分岔隧道的临界风速计算模型,发现无量纲临界风速与无量纲热释放速率仍然具有与单管隧道类似的1/3幂次关系。

关键词：隧道火灾缩尺寸实验临界风速烟气流动特性

基于系统机能曲线的城市道路公共交通系统韧性评估方法

在线全文

学校读者我要写书评

暂无评论

清华大学学报（自然科学版） 2022年第6期62卷 1016-1022页

作者：陈长坤何凡赵冬月谢明峰中南大学防灾科学与安全技术研究所长沙410075

为科学定量评估城市道路公共交通系统韧性,构建了基于系统机能曲线的城市道路公共交通系统韧性评估模型,并提出了一种量化系统韧性的方法。模型中包含公交车系统和出租车系统两个维度,并采用城市公交车服务率和出租车在线率来表征其系... 详细信息

为科学定量评估城市道路公共交通系统韧性,构建了基于系统机能曲线的城市道路公共交通系统韧性评估模型,并提出了一种量化系统韧性的方法。模型中包含公交车系统和出租车系统两个维度,并采用城市公交车服务率和出租车在线率来表征其系统机能,能够综合评估城市道路公共交通系统韧性。用该方法对2021年郑州特大暴雨灾害中的道路公共交通系统韧性进行了计算分析。评估结果表明:郑州市道路公共交通系统处于中等韧性水平,且不同的恢复方案对系统的恢复力和适应力均会产生影响。所建立的模型能够描述系统从受到扰动至达到新的平衡状态各个段的机能水平,从而定量计算城市道路公共交通系统韧性。该方法适用于单一灾害作用情景和多种灾害耦合作用情景,可为提升城市道路公共交通系统应对不确定性扰动的能力提供参考。

关键词：交通系统韧性韧性评估系统机能曲线城市公共交通

在线全文

学校读者我要写书评

暂无评论

暴雨灾害下城市基础设施的事故演化风险分析

灾害学 2022年第3期37卷 12-16,28页

作者：陈长坤孙凤琳赵冬月中南大学防灾科学与安全技术研究所湖南长沙410075

随着城市热岛效应和“温室效应”的加剧,暴雨灾害发生的频率不断增大,导致了城市基础设施事故风险的增加。该文立足于暴雨对城市基建设施的影响,建立了暴雨灾害下城市基建设施的事故演化网络,同时引入复杂网络理论中的网络要素特征参数... 详细信息

随着城市热岛效应和“温室效应”的加剧,暴雨灾害发生的频率不断增大,导致了城市基础设施事故风险的增加。该文立足于暴雨对城市基建设施的影响,建立了暴雨灾害下城市基建设施的事故演化网络,同时引入复杂网络理论中的网络要素特征参数,分别对基建设施事故演化网络中的节点重要度和演化连接边脆弱性进行定量风险评估,并结合两者对演化网络中的不同演化路径进行风险分析。结果得到该城市基础设施事故演化网络中的关键节点和演化连接边,并综合辨识出该网络中的脆弱风险环节,从而为暴雨灾害下城市新老基建设施的风险防控提供参考建议。

关键词：城市暴雨城市基础设施灾害演化风险分析