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Adaptive TDMA slot assignment protocol for vehicular ad-hoc networks

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The Journal of China Universities of Posts and Telecommunications 2013年第1期20卷 11-18,25页

作者： yanG Wei-dong LI Pan LIU yan zhu hong-song College of Information Science and Engineering Henan University of Technology State Key Laboratory of Information Security Institute of Information Engineering the Chinese Academy of Sciences Software and Microelectronics Peking University

This paper proposes a novel adaptive time division vehicular ad-hoc networks. ATSA divides different sets multiple access （TDMA） slot assignment protocol （ATSA） for of time slots according to vehicles moving in opposite directions. When a node accesses the networks, it choices a frame length and competes a slot based on its direction and location to communication with the other nodes. Based on the binary tree algorithm, the frame length is dynamically doubled or shortened, and the ratio of two slot sets is adjusted to decrease the probability of transmission collisions. The theoretical analysis proves ATSA protocol can reduce the time delay at least 20% than the media access control protocol for vehicular ad-hoc networks （VeMAC） and 30% than the ad-hoc. The simulation experiment shows that ATSA has a good scalability and the collisions would be reduced about 50% than VeMAC, channel utilization is significantly improved than several existing protocols.

关键词： media access control (MAC) protocol TDMA slot assignment adaptive frame length binary tree

Updating magnetic resonance imaging of small bowel:Imaging protocols and clinical indications

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World Journal of Gastroenterology 2008年第21期14卷 3403-3409页

作者： Jiong zhu Jian-Rong Xu hong-Xia Gong yan Zhou Department of Radiology Ren Ji Hospital Shanghai Jiao Tong University School of Medicine Shanghai 200127 China

High soft tissue contrast resolution,acquisition of multi-planar images and the possibility to obtain functional information make magnetic resonance an interesting imaging technique to evaluate the small bowel *** absence of ionizing radiation is an important feature of magnetic resonance imaging(MRI) examinations because inflammatory diseases such as Crohn's disease(CD) are studied most frequently,which are prevalent among children and young ***,using modern equipment and a rigorous technical approach,can offer detailed morphologic information and functional data on the small *** article discusses the MRI protocols for small bowel and the MR imaging findings of small bowel diseases,such as CD and small bowel neoplasms.

关键词： Magnetic resonance imaging Small bowel Crohn's Neoplasm

Review of precipitation strengthening in ultrahigh-strength martensitic steel

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 256-269页

作者： Zhihao Tian Chunlei Shang Chaolei Zhang Xiaoye Zhou honghui Wu Shuize Wang Guilin Wu Junheng Gao Jiaming zhu Xinping Mao Institute for Carbon Neutrality University of Science and Technology BeijingBeijing 100083China Institute of Steel Sustainable Technology Liaoning Academy of MaterialsShenyang 110004China Department of Materials Science and Engineering Shenzhen MSU-BIT UniversityShenzhen 518172China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004China School of Civil Engineering Shandong UniversityJinan 250061China

Martensite is an important microstructure in ultrahigh-strength steels,and enhancing the strength of martensitic steels often involves the introduction of precipitated phases within the martensitic *** considerable research efforts devoted to this area,a systematic summary of these advancements is *** review focuses on the precipitates prevalent in ultrahigh-strength martensitic steel,primarily carbides(e.g.,MC,M_(2)C,and M_(3)C)and intermetallic compounds(e.g.,Ni Al,Ni_(3)X,and Fe_(2)Mo).The precipitation-strengthening effect of these precipitates on ultrahigh-strength martensitic steel is discussed from the aspects of heat treatment processes,microstructure of precipitate-strengthened martensite matrix,and mechanical ***,a perspective on the development of precipitation-strengthened martensitic steel is presented to contribute to the advancement of ultrahigh-strength martensitic *** review highlights significant findings,ongoing challenges,and opportunities in the development of ultrahigh-strength martensitic steel.

关键词： ultrahigh-strength martensitic steel precipitation strengthening mechanical property carbide intermetallic compound

Sequence structure controllable polymerization-induced self-assembly

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Science China Chemistry 2024年第1期67卷 390-397页

作者： Zi-Xuan Chang Ren-Man zhu Chun-yan hong Wen-Jian Zhang Department of Polymer Science and Engineering University of Science and Technology of ChinaHefei 230026China Institute of Physical Science and Information Technology Anhui UniversityHefei 230601China Key Laboratory of Environment-Friendly Polymeric Materials of Anhui Province Anhui UniversityHefei 230601China

Polymerization-induced self-assembly(PISA)combines synthesis and self-assembly of artificial polymers in one-pot,which brings us one step closer to emulating ***,the reported PISA formulations primarily focus on developing nano-objects with new chemical compositions and rarely on structural regulation of polymers with specific ***,sequence structure controllable polymerization-induced self-assembly(SCPISA)is reported by using 7-(2-methacryloyloxyethoxy)-4-methylcoumarin(CMA)as a *** the copolymerization of 2-hydroxyethyl methacrylate(HEMA)and CMA,controlled incorporation of CMA units into the polymer chains can be realized by programmable light/heat ***-based P(HEMA-co-CMA)copolymers with the same composition but different sequence structures generate a range of ***,the morphologies of the resultant nano-objects can also be controlled by regulating the feed molar ratio of CMA and HEMA,which is similar to the conventional PISA,but the synthesis procedure is obviously simplified in *** versatility of the methodology is further demonstrated by the fabrication of different functional nano-objects with sequence structure-dependent morphologies in SCPISA systems with different functional monomers.

关键词： polymerization-induced self-assembly sequence-controlled polymers PET-RAFT polymerization

An investigation on stability of biomass reduced manganese dioxide ore

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Acta Metallurgica Sinica(English Letters) 2012年第6期25卷 435-442页

作者： honglei ZHANG Guocai zhu hong yan Yuna ZHAO Fangpu CHEN Wenjuan WANG College of Life Science and Bio-engineering Beijing University of Technology Beijing 100124 China Institute of Nuclear and New Energy Technology Tsinghua University Beijing 102201 China

In this study, how to improve the stability of reduced manganese oxide ore was dis- cussed by investigating reoxidation conditions and kinetics mechanism in the cooling process of manganese dioxide ore reduced by biomass. The effects of the temperature and time, chip size of biomass, raw materials thickness and different additives on stability of the products were determined. The valence variation of manganese in ore and the reoxidation kinetics of reduced products were studied. The results show that decrease of reduction temperature and time, and increase of raw materials thickness and little H2SO4 additive are favorable for the stability of the reduced products. The kinetics mechanism of the reoxidation is controlled by diffusion with dynamic appar- ent activation energy of E1--25.10 ***-1, and conformation of manganese in the process is changed from MnO to Mn3O4.

关键词： Biomass reduction Manganese oxide ore Stability Reoxidationkinetics

Electrochemical behavior of different shelled microcapsule composite copper coatings

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International Journal of Minerals,Metallurgy and Materials 2011年第3期18卷 377-384页

作者： Xiu-qing Xu yan-hong Guo Wei-ping Li Li-qun zhu School of Materials Science and Engineering Beihang University Beijing 100191 China

Copper/liquid microcapsule composite coatings with polyvinyl alcohol （PVA）, gelatin or methyl cellulose （MC） as shell materials were prepared by electrodeposition. The influence of shell materials on the corrosion resistance of the composite coatings in 0.1 M H2SO4 was investigated by means of electrochemical techniques, scanning electron microscopy （SEM）, and energy dispersion spectrometry （EDS）. The results show that the participation of microcapsules can enhance the corrosion resistance of the composite coatings compared with the traditional copper layer. Based on the analysis of electrochemical test results, the release ways of microcapsules were deduced. Gelatin and MC as the shell materials of microcapsules are easy to release quickly in the composite coating. On the contrary, the releasing speed of PVA microcapsules is relatively slow due to their characteristics.

关键词： composite coatings shell materials copper microcapsules electrochemical properties corrosion resistance electrodeposition

Spatial Heterogeneity and Influencing Factors of HFRS Epidemics in Rural and Urban Areas:A Study in Guanzhong Plain of Shaanxi Province,China

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Biomedical and Environmental Sciences 2022年第11期35卷 1012-1024页

作者： zhu Ling Li LI yan Ping LU Liang LI Shu Juan REN hong yan National Institute for Nutrition and Health Chinese Center for Disease Control and PreventionBeijing 100050China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Xi’an Eighth Hospital Xi’an 710061ShaanxiChina State Key Laboratory of Infectious Disease Prevention and Control National Institute for Communicable Disease Control and PreventionChinese Center for Disease Control and PreventionBeijing 102206China

Objective The Guanzhong Plain of Shaanxi Province is a severely afflicted hemorrhagic fever with renal syndrome(HFRS)epidemic area,while HFRS prevalence has decreased in most epidemic areas in *** information is available regarding the leading fine-scale influencing factors in this highly HFRSconcentrated area and the roles of natural environmental and socioeconomic *** investigate this,two regions in the Guanzhong Plain,that is,the Chang’an District and Hu County,with similar geographical environments,different levels of economic development,and high epidemic prevalence,were chosen as representative areas of the HFRS *** Maximum entropy models were constructed based on HFRS cases and fine-scale influencing factors,including meteorological,natural environmental,and socioeconomic factors,from 2014 to *** More than 95% of the HFRS cases in the study area were located in the northern plains,which has an altitude of less than 800 m,with topography contributed 84.1% of the impact on the spatial differentiation of the HFRS *** the northern plains,precipitation and population density jointly affected the spatial differentiation of the HFRS epidemic,with contribution rates of 60.7% and 28.0%,*** comparing the influencing factors of the northern plains of Chang’an District and Hu County,we found that precipitation and the normalized difference vegetation index(NDVI)dominated the HFRS epidemic in the relatively developed Chang’an District,while land-use type,temperature,precipitation and population density dominated the HFRS epidemic in the relatively undeveloped Hu *** Topography was the primary key factor for HFRS prevalence in the Chang’an District and Hu County,and the spatial differentiation of HFRS was dominated by precipitation and population density in the northern *** with the influencing factors of the relatively developed Chang’an District,the developing Hu County was more affected

关键词： Hemorrhagic fever with renal syndrome(HFRS) Spatial heterogeneity Influencing factors Economic development stages Fine scale Maximum Entropy model

Neurons-system-like structured SnS_(2)/CNTs composite for high-performance sodium-ion battery anode

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Rare Metals 2021年第6期40卷 1383-1390页

作者： Ling zhu Xue-Xian yang yan-hong Xiang Peng Kong Xian-Wen Wu School of Physics and Electromechanical Engineering Jishou UniversityJishou 416000China School of Chemistry and Chemical Engineering Jishou UniversityJishou 416000China

Sodium-ion batteries(SIBs)have attracted significant attention with respect to renewable energy power generation systems because of the abundant reserves of sodium on ***,anode materials are presently limited by low energy density,poor rate performance and inferior cycling *** recent years,tin disulfide(SnS_(2))with a particular layered structure has been considered as a promising anode material for SIBs due to its high theoretical capacity and low ***,a nervoussystem-like structured SnS_(2)/CNTs composite was successfully synthesized via a hydrothermal *** SnS_(2)sheets were strung with carbon nanotubes(CNTs)to form a hierarchical porous structure,which is effective for electrolyte diffusion and electronic *** large distance of the(001)plane(0.5899 nm)of SnS_(2)favors Na+insertion-extraction *** from these structural characteristics,SnS_(2)/CNTs electrodes exhibit high specific capacity,excellent rate performance and superior cycling stability.A high charge capacity of 642 mAh·g^(-1)was released at 0.2 A·g^(-1),and then,a high reversible capacity of 427 mAh·g^(-1)was retained after 100 *** charged at 2 A·g^(-1),the SnS_(2)/CNTS electrode maintained a capacity of 282 mAh·g^(-1).The nervous-system-like structure of the SnS_(2)/CNTs composite provides a novel strategy for the development of SIBs with high electrochemical performance.

关键词： SnS_(2)/CNTs Sodium-ion batteries Anode Composite Rate capability

Durability of Concrete with Different Improvement Measures and Its Ser-vice Life Prediction in Island and Reef Environment

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China Ocean Engineering 2022年第6期36卷 947-958页

作者： GONG Wei YU hong-fa MA Hai-yan WANG Nan zhu Hai-wei School of Civil Engineering and Architecture Jiangsu University of Science and TechnologyZhenjiang 212100China Department of Civil and Airport Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China School of Civil Engineering University of Science and Technology LiaoningAnshan 114051China Key Laboratory of Harbor and Marine Structure Durability Technology of the Ministry of Communications CCCC Forth Harbor Engineering Institute Co.Ltd.Guangzhou 510230China

To solve the durability of island and reef concrete engineering in the harsh environment of high temperature,high salt,high humidity and windy,the strength grade of concrete and the type of corrosion inhibitor were used as the influence factors,while the relative dynamic elastic modulus was used as the evaluation *** addition,the law and time variability of the deterioration of concrete,the size effect,environmental similarity and the service life model were *** results showed that improving the strength grade of concrete could improve the durability of concrete,and corrosion inhibitor could slightly improve the durability of ***-varying law of the deterioration of concrete conformed to the univariate quadratic *** with the concrete damage equivalent theory,a size effect model based on the relative dynamic elastic modulus was proposed and verified,and the size effect coefficient was also *** environmental similarity model between simulated and practical island and reef environment was *** with the reliability theory and the first order second moment method,a new service life model of concrete structure was *** authors were convinced that the research will be advantageous to researchers.

关键词： island and reef environment relative dynamic elastic modulus size effect environmental similarity service life model