检索结果-南通市图书馆

Effects of Flux Creep on the Magnetization Curves of High-Temperature Superconductors

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 Physics Letters 1998年第6期15卷 450-452页

作者： wei chong-de department of Physics Peking UniversityBeijing 100871

The effects of flux creep on the magnetization curves of high-temperature superconductors are investigated numerically for Anderson-Kim *** pinning energy at zero current density,U_(c),greatly influences the flux penetration process,a larger U_(c),value reults in a larger penetration *** characteristic of the magnetization curve is also a function of U_(c).The magnetization M and ΔM increase with the increasing U_(c) and depend on the magnetic induction B,so the critical current formula based on Bean model is pot accurate,especially for high-T_(c) superconductor,for which flux creep is a large effect.

关键词： creep magnetization Superconductor

Enantioselective reductive conjugate alkenylation of α,β-enones with keto alkenyl acetates by nickel catalysis

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

Science China Chemistry 2025年第1期68卷 157-162页

作者： Rong-de He Yun-Lei Luo Qiu-Quan Pan Qi-wei Yao Xing-Zhong Shu State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical Engineering Lanzhou University

Reactions involving alkenyl acetates offer cost-effective and environmentally friendly routes for alkene synthesis, yet their asymmetric variant remains elusive. Concurrently, asymmetric conjugate alkenylation predominantly centered on nucleophilic addition using alkenyl–M. This manuscript presents an asymmetric reductive conjugate alkenylation reaction involving alkenyl acetates. The method facilitates the enantioselective addition of keto alkenyl groups to α,β-enones, resulting in the formation of unsaturated diketones—a class of useful structural motifs that are challenging to access otherwise. The use of electron-rich Pyroxy ligand is essential for achieving both high reaction efficiency and enantioselectivity.

关键词： nickel alkenylation asymmetric cross-coupling alkenes

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

水稻细菌性基腐病的发生与防控技术探讨

福建稻麦科技 2013年第4期31卷 35-36页

作者：危崇德福建省邵武市农业局植保植检站福建邵武354000

水稻细菌性基腐病是水稻上重要的细菌病害之一,近几年在南方稻区陆续发生,已给水稻生产带来较为严重威胁。介绍了水稻细菌性基腐病的为害症状、影响因素,并提出了相应的防控技术措施,为有效控制水稻细菌性基腐病提供参考。

关键词：水稻细菌性基腐病影响因素防控技术

在线全文

学校读者我要写书评

暂无评论

习近平关于新质生产力重要论述的原创性贡献

新疆师范大学学报（哲学社会科学版） 2025年第1期46卷 69-77,F0002页

作者：魏崇辉上海交通大学马克思主义学院上海200240

新质生产力的培育与发展是推动中国式现代化和重塑全球经济格局的关键驱动力。习近平总书记关于新质生产力重要论述内涵丰富深刻,其生发于全球化背景下科技革命的深入发展和我国经济转型升级的内在需求,等等。习近平总书记关于新质生产... 详细信息

新质生产力的培育与发展是推动中国式现代化和重塑全球经济格局的关键驱动力。习近平总书记关于新质生产力重要论述内涵丰富深刻,其生发于全球化背景下科技革命的深入发展和我国经济转型升级的内在需求,等等。习近平总书记关于新质生产力重要论述统合了宏观层面、中观层面与微观层面,揭示了发展新质生产力的战略定位、政策导向和实施路径,凸显了对马克思主义生产力理论的原创性发展、对生产力发展规律的原创性认识、对新时代科技革命和产业变革趋势的原创性洞察、对新发展理念的原创性贯彻以及对全球经济治理体系的原创性影响。

关键词：新质生产力科技革命中国式现代化原创性贡献

Boosting Oxygen Evolution Reaction Performance on NiFe‑Based Catalysts Through d‑Orbital Hybridization

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2025年第1期17卷 281-292页

作者： Xing Wang wei Pi Sheng Hu Haifeng Bao Na Yao wei Luo State Key Laboratory of New Textile Materials and Advanced Processing Technology Key Laboratory of New Textile Materials and Applications of Hubei ProvinceSchool of Materials Science and EngineeringWuhan Textile UniversityWuhan 430200People’s Republic of China College of Chemistry and Molecular Sciences Wuhan UniversityWuhan 430072People’s Republic of China

Anion-exchange membrane water electrolyzers(AEMWEs)for green hydrogen production have received intensive attention due to their feasibility of using earth-abundant NiFe-based *** introducing a third metal into NiFe-based catalysts to construct asymmetrical M-NiFe units,the d-orbital and electronic structures can be adjusted,which is an important strategy to achieve sufficient oxygen evolution reaction(OER)performance in ***,the ternary NiFeM(M:La,Mo)catalysts featured with distinct M-NiFe units and varying d-orbitals are reported in this *** and theoretical calculation results reveal that the doping of La leads to optimized hybridization between d orbital in NiFeM and 2p in oxygen,resulting in enhanced adsorption strength of oxygen intermediates,and reduced rate-determining step energy barrier,which is responsible for the enhanced OER *** critically,the obtained NiFeLa catalyst only requires 1.58 V to reach 1 A cm^(−2) in an anion exchange membrane electrolyzer and demonstrates excellent long-term stability of up to 600 h.

关键词： NiFe-based catalysts d-orbital coupling Oxygen evolution reaction Anion exchange membrane electrolyzer

Moment Redistribution Effect of the Continuous Glass Fiber Reinforced Polymer-Concrete Composite Slabs Based on Static Loading Experiment

在线全文

学校读者我要写书评

暂无评论

Structural Durability & Health Monitoring 2025年第1期19卷 105-123页

作者： Zhao-Jun Zhang Wen-wei Wang Jing-Shui Zhen Bo-Cheng Li de-Cheng Cai Yang-Yang Du Hui Huang Offshore Oil Engineering Co.Ltd. Tianjin300461China department of Bridge Engineering School of TransportationSoutheast UniversityNanjing211189China

This study aimed to investigate the moment redistribution in continuous glass fiber reinforced polymer(GFRP)-concrete composite slabs caused by concrete cracking and steel bar yielding in the negative bending moment *** experimental bending moment redistribution test was conducted on continuous GFRP-concrete composite slabs,and a calculation method based on the conjugate beam method was *** composite slabs were formed by combining GFRP profiles with a concrete layer and supported on steel beams to create two-span continuous composite slab *** methods,epoxy resin bonding,and stud connection,were used to connect the composite slabs with the steel *** experimental findings showed that the specimen connected with epoxy resin exhibited two moments redistribution phenomena during the loading process:concrete cracking and steel bar yielding at the internal *** contrast,the composite slab connected with steel beams by studs exhibited only one-moment redistribution phenomenon throughout the loading *** the concrete at the internal support cracked,the bending moment decreased in the internal support section and increased in the midspan *** the steel bars yielded,the bending moment further decreased in the internal support section and increased in the mid-span *** GFRP profiles do not experience cracking,there was no significant decrease in the bending moment of the mid-span *** test specimens experienced compressive failure of concrete at the mid-span *** results showed good agreement between the calculated and experimental values of bending moments in the mid-span section and internal support *** proposed model can effectively predict the moment redistribution behavior of continuous GFRP-concrete composite slabs.

关键词： Moment redistribution GFRP-concrete composite slabs bending moment experimental study analysis model

Discovery of a new family member of arsenic–vanadium polyoxometalates with high catalytic performance for one-pot coupling of CO2, epoxides and amines

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

Tungsten 2025年第1期7卷 80-87页

作者： Fang-Qian Wang Yin Zhang wei-wei Wang Mei-Qian Fu Hong-Bing Mo wei-Dong Yu Chao Liu Jun Yan College of Chemistry and Chemical Engineering Central South University Junior Education department Changsha Normal University School of Science Hunan University of Technology and Business

Arsenic-vanadium polyoxometalates（POMs） represent a family of tremendous potential catalysts owing to their peculiar physical and chemical *** in CO2conversion,using POMs to catalyze the conversion of CO2and epoxide into chemical intermediates is the research ***,A new family number of arsenic-vanadium POMs,[N（CH3）4]4[As8V12O38（H2O）]·2H2O({As8V12O38}),was reported and characterized by single-crystal X-ray diffraction,fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,*** from other allotropicity,{As8V12O38}shows a different structure pattern with an I-43d *** obtained {As8V12O38} was employed as a catalyst for the *** initial catalytic reaction confirmed that {As8V12O38} can catalyze the formation of epoxy carbonate by using 1.01 kPa CO2and epoxide at 70℃.Furtherly,when added amine in the catalytic system,oxazolidinone could be obtained by high yields,which provides an efficient way to convert CO2into profitable ***,a possible catalytic reaction mechanism was proposed by using different characterization analyses.{As8V12O38} first catalyzes the epoxide and CO2to form an epoxy carbonate and then catalyzes epoxy carbonate and benzylamine into oxazolidinone.

关键词： Arsenic CO2 conversion Oxazolidinone Polyoxometalates Vanadium

Solar cycles during the seventeenth century revealed by equatorial aurora records

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Earth and Planetary Physics 2025年第1期9卷 182-187页

作者： Yong wei LiMei Yan Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

Solar cycles are fundamental to astrophysics,space exploration,technological infrastructure,and Earth's climate.A better understanding of these cycles and their history can aid in risk mitigation on Earth,while also deepening our knowledge of stellar physics and solar system *** the solar cycles between 1600 and 1700-especially the post-1645 Maunder Minimum,characterized by significantly reduced solar activity-poses challenges to existing solar activity *** study utilizes a new red equatorial auroral catalog from ancient Korean texts to establish solar cycle patterns from 1623 to ***,a further reevaluation of the solar cycles between 1610 and 1755 identified a total of 13 cycles,diverging from the widely accepted record of 12 cycles during that *** research enhances our understanding of historical solar activity,and underscores the importance of integrating diverse historical sources into modern analyses.

关键词： solar cycle Maunder Minimum solar activity red equatorial aurora West Pacific geomagnetic anomaly

From text to image:challenges in integrating vision into ChatGPT for medical image interpretation

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第2期20卷 487-488页

作者： Shunsuke Koga wei Du department of Pathology and Laboratory Medicine Hospital of the University of PennsylvaniaPhiladelphiaPAUSA

Large language models(LLMs),such as ChatGPT developed by OpenAI,represent a significant advancement in artificial intelligence(AI),designed to understand,generate,and interpret human language by analyzing extensive text *** potential integration into clinical settings offers a promising avenue that could transform clinical diagnosis and decision-making processes in the future(Thirunavukarasu et al.,2023).This article aims to provide an in-depth analysis of LLMs’current and potential impact on clinical *** ability to generate differential diagnosis lists underscores their potential as invaluable tools in medical practice and education(Hirosawa et al.,2023;Koga et al.,2023).

关键词： image diagnosis text