检索结果-南通市图书馆

Science China Earth Sciences 2020年第9期63卷 1422-1424页

作者： Shengqian chen Jianbao LIU Jianhui CHEN Fahu chen Key Laboratory of Western China’s Environmental Systems(Ministry of Education) College of Earth and Environmental ScienceLanzhou UniversityLanzhou 730000China Key Laboratory of Alpine Ecology Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China CAS Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of SciencesBeijing 100101China

The arid and semi-arid region of East Asia,principally including the deserts in eastern and western China,is the main dust source of the Northern Hemisphere.Dust storm activity in the region has attracted much researc... 详细信息

关键词： storm eastern dust

Preparation and characterization of bioactive glass tablets and evaluation of bioactivity and cytotoxicity in vitro

在线全文

学校读者我要写书评

暂无评论

Bioactive Materials 2018年第3期3卷 315-321页

作者： Jianhui CHEN Lei Zeng Xiaofeng chen Tianshun Liao Jiafu Zheng Department of Biomedical Engineering School of Materials Science and EngineeringSouth China University of TechnologyGuangzhou 510641China National Engineering Research Center for Tissue Restoration and Reconstruction Guangzhou 510006China Key Laboratory of Biomedical Materials and Engineering Ministry of EducationSouth China University of TechnologyGuangzhou 510006China

In this study, the SiO2eCaOeP2O5 ternary component of bioactive glass particles were successfullysynthesized by sol-gel method, then the bioactive glass particles were pressed into tablets with drypressing molding technology. The physicochemical structure, in-vitro bioactivity and biocompatibility ofBG tablets were characterized by various methods, such as XRD、SEM、FTIR, etc. The results showedthat the sol-gel bioactive glass particle was distinguished with its amorphous structure and micron-size.After being soaked in Tris-Hcl solution for 15 d, the bioactive glass tablets didn't collapse. Also, themineralization assay in vitro showed that the bioactive glass tablets had good capability of inducing theformation of hydroxycarbonate apatite (HCA) after being immersed in simulated body fluid (SBF). Inaddition, the cytotoxicity assay indicated that the osteoblast (MC3T3) grew well on the surface ofbioactive glass tablets. According to the above results, the bioactive glass tablets presented good mechanicalstrength, excellent apatite-forming activity and high biocompatibility, which demonstratedtheir potential applications in the field of bone defect repairing.

关键词： Sol-gel bioactive glass Dry pressing molding BG tablets Bioactivity Cytotoxicity

Recent Advances in Hydrometallation of Alkenes and Alkynes via the First Row Transition Metal Catalysis

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 Journal of Chemistry 2018年第11期36卷 1075-1109页

作者： Jianhui CHEN Jun Guo Zhan Lu College of Chemistry and Materials Engineering Wenzhou University Wenzhou Zhejiang 325035 China Department of chemistry Zhejiang University Hangzhou Zhejiang 310027China

Hydrometallation of alkenes and alkynes provides a straightforward route to access alkyl‐ or alkenyl‐metal reagents, which have a wide range of applications in organic transformations. In recent years, the first row transition metals (such as copper, nickel, cobalt, iron, etc .) have emerged high activity and selectivity in this area with the aid of a variety of ligands. This review covers the recent advances in the hydrometallation of minimally functionalized unsaturated C—C bonds (including alkenes, alkynes, dienes, allenes, enynes, etc .), as well as transformations involving catalytic hydrometallation process via the first row transition metal catalysis.

关键词： hydrometallation the first row transition metals alkenes alkynes metal‐hydride

In-situ construction of high-mechanical-strength and fast-ion-conductivity interphase for anode-free Li battery

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2023年第5期80卷 207-214,I0006页

作者： Yangfan Lin Juner chen Han Zhang jianhui Wang Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province School of EngineeringWestlake UniversityHangzhou 310024ZhejiangChina Institute of Advanced Technology Westlake Institute for Advanced StudyHangzhou 310024ZhejiangChina Department of Chemistry Zhejiang UniversityHangzhou 310027ZhejiangChina

The solid electrolyte interphase(SEI)with strong mechanical strength and high ion conductivity is highly desired for Li metal batteries,especially for harsh anode-free batteries.Herein,we report a pragmatic approach to the in-situ construction of high-quality SEI by applying synergistic additives of Li NO_(3)and ethylene sulfite(ES)in the electrolyte.The obtained SEI exhibits a high average Young’s modulus(9.02GPa)and exchanging current density(4.59 mA cm^(-2)),which are 3.0 and 1.2 times as large as those using the sole additive of LiNO_(3),respectively.With this improved SEI,Li-dendrite growth and side reactions are effectively suppressed,leading to an ultra-high Coulombic efficiency(CE)of 99.7%for Li plating and stripping.When applying this improved electrolyte in full cells,it achieves a high capacity retention of 89.7%for over 150 cycles in a LiFePO_(4)||Li battery(~12 mg cm^(-2)cathode,50μm Li)and of 44.5%over 100 cycles in a LiFePO_(4)||Cu anode-free battery.

关键词： Anode-free Li battery Solid electrolyte interphase Additive Lithiu mnitrate Ethylene sulfite

Changes in vegetation and moisture in the northern Tianshan of China over the past 450 years

在线全文

学校读者我要写书评

暂无评论

Frontiers of Earth Science 2020年第2期14卷 479-491页

作者： Weihe REN Yan ZHAO Quan LI Jianhui CHEN Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of West China’s Environmental System(Ministry of Education) College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China

Knowledge of historical changes in moisture within semi-arid and arid regions is the basis of climatic change predictions and strategies in response to long-term drought.In this study,a multiproxy peat record with highresolution from Sichanghu in the northern Tianshan was used to document the changes in vegetation and climate over the past 450 years in the arid Central Asia.The pollen,grain size,and loss on ignition(LOI)records indicate that the productivity of local peat began to increase at^1730 AD.The vegetation in the Sichanghu area experienced several transitions,from temperate desert to dense desert,marsh meadow,and steppe desert vegetation.The climate in the study area was extremely dry during the early stages of the Little Ice Age(LIA)(before 1730 AD)and relatively wet during the late stages(1730–1880 AD).The inferred changes in the moisture conditions of the Sichanghu peatland since the LIA may have been controlled by the extent of Arctic sea ice,the North Atlantic Oscillation,and the Siberian High via the connections of large-scale atmospheric circulations such as the Westerlies.

关键词： Little Ice Age pollen vegetation change moisture condition Tianshan arid Central Asia

A Multi-Objective Optimization Method of Initial Virtual Machine Fault-Tolerant Placement for Star Topological Data Centers of Cloud Systems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2021年第1期26卷 95-111页

作者： Wei Zhang Xiao chen jianhui Jiang the School of Software Engineering Tongji UniversityShanghai 201804China

Virtualization is the most important technology in the unified resource layer of cloud computing systems.Static placement and dynamic management are two types of Virtual Machine(VM)management methods.VM dynamic management is based on the structure of the initial VM placement,and this initial structure will affect the efficiency of VM dynamic management.When a VM fails,cloud applications deployed on the faulty VM will crash if fault tolerance is not considered.In this study,a model of initial VM fault-tolerant placement for star topological data centers of cloud systems is built on the basis of multiple factors,including the service-level agreement violation rate,resource remaining rate,power consumption rate,failure rate,and fault tolerance cost.Then,a heuristic ant colony algorithm is proposed to solve the model.The service-providing VMs are placed by the ant colony algorithms,and the redundant VMs are placed by the conventional heuristic algorithms.The experimental results obtained from the simulation,real cluster,and fault injection experiments show that the proposed method can achieve better VM fault-tolerant placement solution than that of the traditional first fit or best fit descending method.

关键词： cloud computing virtual machine placement fault tolerance multi-objective optimization heuristic ant colony algorithm

Identifying interlinkages between urbanization and Sustainable Development Goals

在线全文

学校读者我要写书评

暂无评论

Geography and Sustainability 2022年第4期3卷 339-346页

作者： Mingxing chen Liangkan chen Jiafan cheng jianhui Yu Key Laboratory of Regional Sustainable Development Modeling Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China College of Resource and Environment University of Chinese Academy of SciencesBeijing 100049China

Urbanization and Sustainable Development Goals(SDGs)are important global issues in the current“Anthropocene”.Climate change and the COVID-19 pandemic have exacerbated global urban problems and hindered the ability to meet SDGs on time,while the broad interlinkages between urbanization and the SDGs remain poorly understood.This study shows that among the interlinkages of urbanization with 17 SDGs,synergies are observed with 151 targets(89%),among which 67(40%)have stronger synergies,and trade-offs are observed with 66 targets(39%),among which 31(18%)have stronger trade-offs.Furthermore,the synergies and trade-offs between urbanization and the achievement of SDGs are specifically analyzed based on four fundamental interaction fields:(a)public health and social welfare equality;(b)energy consumption and economic growth;(c)natural resource use and ecological/environmental impacts;and(d)international cooperation for development.Finally,based on these analyses,we propose four recommendations for sustainable urbanization,including(a)shared well-being and spatial justice for urban and rural residents;(b)guiding green and low-carbon urban development;(c)building resilient cities;and(d)promoting multilateral cooperation in cities,which can contribute to the achievement of SDGs by 2030.

关键词： Urbanization Sustainable Development Goals(SDGs) Synergies Trade-offs Well-being Anthropocene

Spatiotemporal variations of aridity in China during 1961–2015: decomposition and attribution

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science Bulletin 2018年第18期63卷 1187-1199页

作者： Chang Liu Wei Huang Song Feng Jianhui CHEN Aifeng Zhou Key Laboratory of Western China's Environmental Systems (Ministry of Education). College of Earth and Environmental Sciences Lanzhou University Lanzhou 730000 China Department of Geosciences University of Arkansas Fayetteville AR 72703 USA

Changes in global climate intensify the hydrological cycle, directly influence precipitation, evaporation,runoff, and cause the re-distribution of water resources in time and space. The aridity index (AI), defined as the ratio of annual precipitation to annual potential evapotranspiration, is a widely used numerical indicator to quantify the degree of dryness at a given location. This study examined the effects of climate change on AI in China during 1961–2015. The results showed that the nationally averaged AI experienced a notable interdecadal transition in 1993, characterized by increasing AI (wetter) between 1961 and 1993,and decreasing AI (drier) after 1993. Overall, the decreased solar radiation (solar dimming) was the main factor affected the nationally averaged AI during 1961–1993, while the relative humidity dominated the variations of nationally averaged AI during 1993–2015. However, the roles of individual factors on the changes in AI vary in different subregions. Precipitation is one of the important contributing factors for the changes of AI in almost all subregions, except the Mid-Lower Yangtze and Huaihe basins. Solar radiation has been significantly decreased during 1961–1993 in South China, Southwest China, Mid-Lower Yangtze and Huaihe basins, and the Tibetan Plateau. Therefore, it dominated the trends of AI in these subregions.The relative humidity mainly affected the Mid-Lower Yangtze and Huaihe basins, Southwest China, and the Tibetan Plateau during 1993–2015, hence dominated the trends of AI in these subregions. The changes of temperature and wind speed, however, played a relatively weak role in the variations of AI.

关键词：土壤水分蒸发蒸腾损失总量中国干旱时间空间分解相对湿度全球气候

A Two-point Method for Multiaxial Fatigue Life Prediction

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2022年第2期35卷 316-327页

作者： jianhui Liu Xuemei Pan Youtang Li Xiaochuang chen School of Mechanical and Electrical Engineering Lanzhou University of TechnologyLanzhou 730050China Lanzhou Jinchuan Advanced Materials Technology Co. Ltd.Lanzhou 730101China

Fatigue fracture is one of the most common failure modes of engineering compo-nents,and the combined action of geometrie discontinuity and multiaxial loading is more likely to cause severe fatigue damage of components.This work focuses on the fatigue behavior of U-notched Q345 steel specimens with differen t notch sizes under proportional cyclic tension-torsion.Firstly,based on the concept of strain energy,the calculation method of critical plane is given and the equivalent stress of the specified path on the critical plane is extracted to char-acterize the equivalent stress distribution state and the stress gradient effect.Then,based on the high stress volume method and theory of critical distance,a simple method for determining the critical distance is given considering the contribution of stress at the dangerous point and the critical point.In addition,based on the idea of stress-distance normalization,a new stress gradient impact factor is defined and a new method for predicting the multiaxial fatigue life of notched specimens is given.The prediction results of the proposed model,the local stress-strain method and the point method of theory of critical distance are compared with the experimental results.The comparisons show that the prediction results of the proposed model are closer to experimentai life,and the calculation accuracy is higher.

关键词： Multiaxial fatigue Stress gradient Life prediction Critical distance method Local stress-strain method

Loop Subgraph-Level Greedy Mapping Algorithm for Grid Coarse-Grained Reconfigurable Array

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2023年第2期28卷 330-343页

作者： Naijin chen Fei cheng chenghao Han jianhui Jiang Xiaoqing Wen School of Computer and Information Science Anhui Polytechnic UniversityWuhu 241000China School of Software Engineering Tongji UniversityShanghai 201804China Department of Computer Science and Networks Kyushu Institute of TechnologyFukuoka 820-8502Japan

To solve the problem of grid coarse-grained reconfigurable array task mapping under multiple constraints,we propose a Loop Subgraph-Level Greedy Mapping(LSLGM)algorithm using parallelism and processing element fragmentation.Under the constraint of a reconfigurable array,the LSLGM algorithm schedules node from a ready queue to the current reconfigurable cell array block.After mapping a node,its successor’s indegree value will be dynamically updated.If its successor’s indegree is zero,it will be directly scheduled to the ready queue;otherwise,the predecessor must be dynamically checked.If the predecessor cannot be mapped,it will be scheduled to a blocking queue.To dynamically adjust the ready node scheduling order,the scheduling function is constructed by exploiting factors,such as node number,node level,and node dependency.Compared with the loop subgraph-level mapping algorithm,experimental results show that the total cycles of the LSLGM algorithm decreases by an average of 33.0%(PEA44)and 33.9%(PEA_(7×7)).Compared with the epimorphism map algorithm,the total cycles of the LSLGM algorithm decrease by an average of 38.1%(PEA_(4×4))and 39.0%(PEA_(7×7)).The feasibility of LSLGM is verified.

关键词： Grid Coarse-Grained Reconfigurable Array(GCGRA) mapping loop subgraph scheduling