检索结果-南通市图书馆

Characteristics and distribution of microstructures in high pressure die cast alloys with X-ray microtomography:A review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Foundry 2024年第5期21卷 427-444页

作者： Hai-dong Zhao Xue-ling wang Qian wan Wen-hui Bai Fei Liu School of Mechanical and Automotive Engineering South China University of TechnologyGuangzhou 510640China

Al and Mg alloy high pressure die castings(HPDC)are increasingly used in automotive *** microstructures in the castings have decisive effect on the casting mechanical properties,in which the microstructure characteristics are fundamental for the investigation of the microstructure-property *** the past decade,the microstructure characteristics of HPDC Al and Mg alloys,especially micro-pores andα-Fe,have been investigated from two-dimensional(2D)to threedimensional with X-ray micro-computed tomography(μ-CT).This paper provides an overview of the current understanding regarding the 3D characteristics and formation mechanisms of microstructures in HPDC alloys,their spatial distributions,and the impact on mechanical ***,it outlines future research directions for the formation and control of heterogeneous microstructures in HPDC alloys.

关键词： high pressure die casting microstructure three-dimensional characteristics distribution Al and Mg alloys

In situ infrared, Raman and X-ray spectroscopy for the mechanistic understanding of hydrogen evolution reaction

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 2024年第3期90卷 632-651,I0014页

作者： Andi Haryanto Kyounghoon Jung Chan Woo Lee dong-wan Kim Department of Chemistry Kookmin UniversitySeoul 02707Republic of Korea School of Civil Environmental and Architectural EngineeringKorea UniversitySeoul 02841Republic of Korea

Hydrogen production by water reduction reactions has received considerable attention because hydrogen is considered a clean-energy carrier,key for a sustainable energy *** methods have been widely used to study the reaction mechanism of the hydrogen evolution reaction(HER),but the calculation results need to be supported by experimental results and direct evidence to confirm the mechanistic *** this review,we discuss the fundamental principles of the in situ spectroscopic strategy and a theoretical model for a mechanistic understanding of the *** addition,we investigate recent studies by in situ Fourier transform infrared(FTIR),Raman spectroscopy,and X-ray absorption spectroscopy(XAS) and cover new findings that occur at the catalyst-electrolyte interface during *** spectroscopic strategies provide practical ways to elucidate catalyst phase,reaction intermediate,catalyst-electrolyte interface,intermediate binding energy,metal valency state,and coordination environment during HER.

关键词： Hydrogen evolution reaction Infrared spectroscopy Raman spectroscopy X-ray absorption spectroscopy Reaction mechanism

On hypersurfaces of H2×H2

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2024年第2期67卷 339-366页

作者： dong Gao hui Ma Zeke Yao School of Science Beijing University of Civil Engineering and Architecture Department of Mathematical Sciences Tsinghua University

In this paper, we study hypersurfaces of H2× H2. We first classify the hypersurfaces with constant principal curvatures and constant product angle functions. Then we classify homogeneous hypersurfaces and isoparametric hypersurfaces, respectively. Finally, we classify the hypersurfaces with at most two distinct constant principal curvatures, as well as those with three distinct constant principal curvatures under some additional conditions.

关键词： constant principal curvature homogeneous hypersurface isoparametric hypersurface 53C42 53B25 53C40

Neg-Entropy Mechanism as a Target for Natural Medicines

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Engineering 2024年第7期38卷 11-12页

作者： Tian-Le Gao hui-hui Guo Jian-dong Jiang Institute of Materia Medica Chinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100050China Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100050China

Current strategies for drug discovery research mainly focus on molecular targets,in which structure biology plays a central role,such as the detailed mechanism of a drug-target *** principle of this approach is the presumed molecular mechanism or genetic background of the disease being *** this approach has brought progress in understanding the mode of action for some drugs,most prevalent illnesses-especially chronic diseases-are multifactorial and present with a group of symptoms,as is often the case in cardiovascular diseases,metabolic disorders,cancers,and so *** newly emerging term“multi-morbidity”(i.e.,multiple co-occurring diseases)describes a grand challenge for this strategy,and successful drug intervention for multimorbidity should be multifaceted[1].So,our research team has shifted its attention to a new direction that views the disease as a whole instead of a single-molecule abnormality,and focusing on drugs with multiple targets.

关键词： drugs diseases cardiovascular

Boosted Lithium-Ion Transport Kinetics in n-Type Siloxene Anodes Enabled by Selective Nucleophilic Substitution of Phosphorus

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano-Micro Letters 2024年第10期16卷 618-637页

作者： Se In Kim Woong-Ju Kim Jin Gu Kang dong-wan Kim School of Civil Environmental and Architectural EngineeringKorea University02841 SeoulSouth Korea Nanophotonics Research Center Korea Institute of Science and Technology02792 SeoulSouth Korea

Doped two-dimensional(2D)materials hold significant promise for advancing many technologies,such as microelectronics,optoelectronics,and energy ***,n-type 2D oxidized Si nanosheets,namely n-type siloxene(n-SX),are employed as Li-ion battery *** thermal evaporation of sodium hypophosphite at 275℃,P atoms are effectively incorporated into siloxene(SX)without compromising its 2D layered morphology and unique Kautsky-type crystal ***,selective nucleophilic substitution occurs,with only Si atoms being replaced by P atoms in the O_(3)≡Si-H *** resulting n-SX possesses two delocalized electrons arising from the presence of two electron donor types:(i)P atoms residing in Si sites and(ii)H *** doping concentrations are varied by controlling the amount of precursors or their mean free *** at 2000 mA g^(-1),the n-SX electrode with the optimized doping concentration(6.7×10^(19) atoms cm^(-3))delivers a capacity of 594 mAh g^(-1) with a 73%capacity retention after 500 *** improvements originate from the enhanced kinetics of charge transport processes,including electronic conduction,charge transfer,and solid-state *** approach proposed herein offers an unprecedented route for engineering SX anodes to boost Li-ion storage.

关键词： Li-ion battery Two-dimensional N-type siloxene Doping mechanism Kinetics

0^(--) hidden-heavy tetraquark states via QCD sum rules

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2024年第9期48卷 50-59页

作者： Bing-dong wan Hong-Tai Xu Department of Physics Liaoning Normal UniversityDalian 116029China Center for Theoretical and Experimental High Energy Physics Liaoning Normal UniversityDalian 116029China

In this study,we evaluated the mass spectra of the prospective 0^(--) hidden-charm and hidden-bottom tetraquark states in molecular configuration via QCD sum *** our calculation,the nonperturbative condensate contributions are considered up to dimension eight in operator product *** is found that there could exist 4possible 0^(--) hidden-charm tetraquark states with masses(4.68±0.07),(4.22±0.09),(4.53±0.09),and(4.26±0.13) *** corresponding hidden-bottom partners are found lying at(11.04±0.10),(10.71±0.12),(11.09±0.10),and(11.82±0.14) GeV,*** possible tetraquark decay modes were analyzed,which are expected to be measured in BESⅢ,BELLEⅡ,and LHCb experiments.

关键词： exotic hadronic states QCD sum rules tetraquarks

Review on inorganic and polymeric materials-coordinated metal-organic-framework photocatalysts for green hydrogen evolution

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第5期92卷 322-356页

作者： dong-Eun Lee Mohtaram Danish Umair Alam wan-Kuen Jo School of Architecture CivilEnvironmental and Energy Engineering Kyungpook National University80 Daehak-roBuk-guDaegu 41566Republic of Korea School of Chemical Engineering Yeungnam UniversityGyeongsanGyeongbuk 38541Republic of Korea

Metal-organic frameworks(MOFs)possess a distinct advantage over conventional heterogeneous photocatalysts because of their carefully defined architecture and particular pores,which facilitate the targeted incorporation of other efficient cocatalysts or semiconductor *** integration of MOFs with other materials has resulted in significant breakthroughs,as the coupled materials improve the performance due to the combined *** unique MOF structures allow them to host foreign materials,which results in harvesting the visible region of the solar spectrum and effectively mitigating charge recombination by promoting charge *** review presents an evaluation of the latest developments in the utilization of surface and/or pore chemistry of MOF-supported heterojunctions for photocatalytic green-hydrogen generation with a basic understanding of the mechanism *** review begins with the basic principles of photocatalysis,the significance of MOFs,their optical properties,the methods used for synthesizing MOFs,and their coordination with other inorganic and polymeric ***,methods to increase photocatalytic H2 evolution using MOF-supported heterojunction have been proposed as standard ***,to address environmental challenges,we highlight the future potential of MOF-supported heterojunctions for use in green-energy *** hope that this review provides guidance to researchers in the development of effective heterojunctions based on MOFs to address challenges in energy applications and catalytic processes.

关键词： Renewable energy Environmental challenge Heterojunction Water splitting Photocatalysis

Proactive Caching at the Wireless Edge:A Novel Predictive User Popularity-Aware Approach

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2024年第8期140卷 1997-2017页

作者： Yunye wan Peng Chen Yunni Xia Yong Ma dongge Zhu Xu wang hui Liu Weiling Li Xianhua Niu Lei Xu Yumin dong College of Computer Science Chongqing UniversityChongqing400044China School of Computer and Software Engineering Xihua UniversityChengdu610039China School of Computer and Information Engineering Jiangxi Normal UniversityNanchang330022China Electric Power Research Institute of State Grid Ningxia Electric Power Co. Ltd.Yinchuan750002China College of Mechanical and Vehicle Engineering Chongqing UniversityChongqing400030China School of Computer Science and Technology Beijing Institute of TechnologyBeijing100083China School of Computer Science and Technology Dongguan University of TechnologyDongguan523808China School of Emergency Management Xihua UniversityChengdu610039China College of Computer and Information Science Chongqing Normal UniversityChongqing401331China

Mobile Edge Computing(MEC)is a promising technology that provides on-demand computing and efficient storage services as close to end users as *** an MEC environment,servers are deployed closer to mobile terminals to exploit storage infrastructure,improve content delivery efficiency,and enhance user ***,due to the limited capacity of edge servers,it remains a significant challenge to meet the changing,time-varying,and customized needs for highly diversified content of ***,techniques for caching content at the edge are becoming popular for addressing the above *** is capable of filling the communication gap between the users and content providers while relieving pressure on remote cloud ***,existing static caching strategies are still inefficient in handling the dynamics of the time-varying popularity of content and meeting users’demands for highly diversified entity *** address this challenge,we introduce a novel method for content caching over MEC,i.e.,*** synthesizes a content popularity prediction model,which takes users’stay time and their request traces as inputs,and a deep reinforcement learning model for yielding dynamic caching *** results demonstrate that PRIME,when tested upon the MovieLens 1M dataset for user request patterns and the Shanghai Telecom dataset for user mobility,outperforms its peers in terms of cache hit rates,transmission latency,and system cost.

关键词： Mobile edge computing content caching system average cost deep reinforcement learning collaborative mechanism

Optimal investment based on relative performance and weighted utility

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 328-342页

作者： wanG Lei dong Ying-hui HUA Chun-rong Department of Mathematics Suzhou University of Science and TechnologySuzhou 215009China Changshu Institute of Technology Changshu 215500China

This paper studies the optimal portfolio allocation of a fund manager when he bases decisions on both the absolute level of terminal relative performance and the change value of terminal relative performance comparison to a predefined reference point. We find the optimal investment strategy by maximizing a weighted average utility of a concave utility and an Sshaped utility via a concavification technique and the martingale method. Numerical results are carried out to show the impact of the extent to which the manager pays attention to the change of relative performance related to the reference point on the optimal terminal relative performance.

关键词： relative performance weighted utility S-shaped utility concavification