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Visible-light-induced organocatalyzed C(sp^(2))–H bond functionalization of 1,3-azoles with trifluoroacetylsilanes

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Science China Chemistry 2024年第11期67卷 3662-3668页

作者： Zhengyu Li Zeguo zhang zhihan zhang Gang Zhou Yizhi zhang Shanshan Liu Xiao Shen The Institute for Advanced Studies Engineering Research Center of Organosilicon Compounds&MaterialsMinistry of EducationWuhan UniversityWuhan 430072China College of Chemistry Central China Normal UniversityWuhan 430079China

Previous carbene insertion to C–H bonds of 1,3-azoles relied on metal carbene species. Herein, we report a metal-free C(sp^(2))–H bond functionalization of 1,3-azoles with trifluoroacetylsilanes. The reaction features mild conditions, broad substrate scope and wide functional group tolerance. The mechanistic study supports that the success of the reaction is probably attributed to the dual roles of trifluoroacetylsilanes under the photocatalyzed conditions: generating carbenes which undergo cyclopropanation and generating biradicals which promote ring-opening aromatization of the in situ generated fused cyclopropanes.

关键词： C(sp^(2))–H bond functionalization carbenes biradicals cyclopropanation brook rearrangement

基于熵权法的CA砂浆脱空位置对单元式无砟轨道动力状态影响评价研究

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铁道科学与工程学报 2025年第1期22卷 125-135页

作者：张芷寒高亮郭志鹏赵书鑫钟阳龙王继姜涵文北京交通大学土木建筑工程学院北京100044 中建交通建设集团有限公司北京100166

随着高速铁路运营时间增加,CRTSⅠ型板式无砟轨道脱空现象日益加剧。多种因素影响造成的脱空在空间位置上随机分布。为明确脱空位置对轨道结构动态服役性能的影响,提出时、频域融合的轨道动力状态综合评价方法。为验证构建的轨道动力状... 详细信息

随着高速铁路运营时间增加,CRTSⅠ型板式无砟轨道脱空现象日益加剧。多种因素影响造成的脱空在空间位置上随机分布。为明确脱空位置对轨道结构动态服役性能的影响,提出时、频域融合的轨道动力状态综合评价方法。为验证构建的轨道动力状态综合评价方法的有效性和准确性,建立高速车辆-无砟轨道-路基系统耦合动力学模型,获取不同脱空位置下的轨道结构动力响应;选取钢轨、轨道板、底座板和路基子结构为研究对象,将各结构加速度、位移响应的时程和功率谱密度特征作为评价指标,采用波形因子、脉冲因子、峭度因子、偏度因子和裕度因子指标对时、频域评价指标进行无量纲处理;并采用熵权法实现砂浆脱空位置对轨道动力状态的影响评价。研究结果表明:对比无脱空、板边脱空、板中脱空条件下轨道结构振动加速度的时、频域响应结果可知,钢轨、轨道板垂向加速度受板边脱空影响整体大于板中脱空影响,但板边/板中不同纵向位置脱空产生的加速度峰值相差不大;脱空会造成钢轨、轨道板加速度共振峰的前移,但仅靠时、频域响应难以准确描述不同CA砂浆脱空位置对轨道结构动力状态的影响规律。而采用熵权法建立的轨道动力状态评价结果可知,沿线路纵向不同位置处的脱空,板端位置脱空对轨道结构的影响更大;线路横向不同位置处的脱空,板边位置脱空对轨道结构的动力状态影响更大;CA砂浆脱空的最不利位置为板端角处。研究结果可为其他条件下的轨道结构服役状态的判定提供借鉴,并为轨道结构科学准确的养护维修提供参考依据。

关键词：高速铁路无砟轨道砂浆脱空熵权法动力状态

Pinless Friction Stir Welding of AA2024-T3Joint and Its Failure Modes

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Transactions of Tianjin University 2014年第6期20卷 439-443页

作者： Li Wenya Li Jinfeng zhang zhihan Gao Dalu Wang Weibing Luan Guohong State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an710072China China FSW Center Beijing 100024China

The joining of aluminum alloy sheets with thickness less than 2.0 mm is difficult via conventional frictionstir welding owing to the defects in the joint, such as root flaw, keyhole and lazy S. In the present research, a newlydesigned pinless tool with involute grooves on its shoulder surface was applied to weld 1.5 mm thick AA2024-T3. Theeffects of the rotating speed and welding speed on the microstructure and mechanical properties of the joints were *** experimental results showed that the root flaw and keyhole were successfully eliminated. The lazy S wasalso eliminated under the optimized welding parameters. The maximum tensile strength of the joints was 326 MPa,which is about 74.1% that of the base material. Moreover, all the tensile samples fractured from the retreating *** fracture modes were observed during the tensile tests, which are related with the lazy S.

关键词： pinless friction stir welding AA2024-T3 mechanical property fracture mode

Non-isothermal kinetics and characteristics of calcium carbide nitridation reaction with calcium-based additives

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Frontiers of Chemical Science and Engineering 2024年第4期18卷 49-61页

作者： zhihan zhang Mengxiao Yu Xiaoyu zhang Jinli zhang You Han School of Chemical Engineering and Technology Tianjin UniversityTianjin 300350China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China

The nitridation reaction of calcium carbide and N_(2) at high temperatures is the key step in the production of ***,the challenges faced by this process,such as high energy consumption and poor product quality,are mainly attributed to the lack of profound understanding of the *** study aimed to improve this process by investigating the non-isothermal kinetics and reaction characteristics of calcium carbide nitridation reaction at different heating rates(10,15,20,and 30℃·min^(-1))using thermogravimetric *** kinetic equation for the nitridation reaction of additive-free calcium carbide sample was obtained by combining model-free methods and model-fitting *** effect of different calcium-based additives(CaCl_(2) and CaF_(2))on the reaction was also *** results showed that the calcium-based additives significantly reduced reaction temperature and activation energy E_(a) by about 40% with CaF_(2) and by 55%-60% with CaCl_(2).The reaction model f(α)was also changed from contracting volume(R3)to 3-D diffusion models with D3 for CaCl_(2) and D4 for CaF_(2).This study provides valuable information on the mechanism and kinetics of calcium carbide nitridation reaction and new insights into the improvement of the lime-nitrogen process using calcium-based additives.

关键词： lime-nitrogen calcium carbide calciumbased additive thermogravimetric analysis nonisothermal kinetics

The Influence of IWOM on Restaurant Consumers’ Purchase Intentions: Taking PANGGELIA as an Example

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Journal of Contemporary Educational Research 2022年第4期6卷 94-101页

作者： zhihan zhang Jinan University Shenzhen 518000China

This paper explores the factors influencing consumers’willingness to purchase under the influence of IWOM,taking perceived risk as the theoretical *** factors influencing consumers’willingness to purchase under IWOM are investigated from three perspectives:perceived functional risk,perceived psychological risk,and perceived financial risk.A combination of quantitative and qualitative research methods is used to derive the questionnaire theory using the interview *** research findings are drawn using the questionnaire method and combined with the path analysis *** on the research results,relevant suggestions and countermeasures are proposed for such IWOM-influenced restaurants.

关键词： IWOM Purchase intention Perceived risk

Intelligent acupuncture:data-driven revolution of traditional Chinese medicine

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Acupuncture and Herbal Medicine 2023年第4期3卷 271-284页

作者： Yunfan Bao Haokang Ding zhihan zhang Kunhuan Yang Queena Tran Qi Sun Tiancheng Xu Key Laboratory of Acupuncture and Medicine Research of Ministry of Education Nanjing University of Chinese MedicineNanjingChina Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica Nanjing University of Chinese MedicineNanjingChina School of Life Science and Chemistry and Chemical Engineering Jiangsu Second Normal UniversityNanjingChina College of Letters&Science University of CaliforniaBerkeleyUSA School of Computer Science and Engineering Nanjing University of Science and TechnologyNanjingChina Zhimei Kangmin(Zhuhai)Health Technology Co. LTDZhuhaiChina

Acupuncture,a form of traditional Chinese medicine with a history of 2,000 years in China,has gained wider acceptance worldwide as a complementary *** have examined its effectiveness in various health conditions and it is commonly used alongside conventional medical *** the development of artificial intelligence(AI)technology,new possibilities for improving the efficacy and precision of acupuncture have *** study explored the combination of traditional acupuncture and AI technology from three perspectives:acupuncture diagnosis,prescription,and treatment *** study aimed to provide cutting-edge direction and theoretical assistance for the development of an acupuncture robot.

关键词： Acupuncture Artificial intelligence Knowledge graph Graphical abstract:http://***/AHM/A68

Application of LSTM and CONV1D LSTM Network in Stock Forecasting Model

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Artificial Intelligence Advances 2021年第1期3卷 36-43页

作者： Qiaoyu Wang Kai Kang zhihan zhang Demou Cao Electrical and Computer Systems Engineering Department Monash UniversityMelbourneVictoriaAustralia

Predicting the direction of the stock market has always been a huge ***,the way of forecasting the stock market reduces the risk in the financial market,thus ensuring that brokers can make normal *** the complexities of the stock market,the challenge has been increasingly addressed by experts in a variety of disciplines,including economics,statistics,and computer *** introduction of machine learning,in-depth understanding of the prospects of the financial market,thus doing many experiments to predict the future so that the stock price trend has different degrees of *** this paper,we propose a method to predict stocks from different industries and markets,as well as trend prediction using traditional machine learning algorithms such as linear regression,polynomial regression and learning techniques in time series prediction using two forms of special types of recursive neural networks:long and short time memory(LSTM)and spoken short-term memory.

关键词： Linear regression Polynomial regression Long short-term memory network One dimensional convolutional neural network

A 4-element Rectangular Microstrip Patch Antenna Array

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Modern Electronic Technology 2021年第2期5卷 7-12页

作者： Demou Cao zhihan zhang Kai Kang Qiaoyu Wang Electrical and Computer Systems Engineering Department Monash UniversityMelbourneVictoriaAustralia

Patch antennas are small in size and suitable for microwave transmission,so they are widely used in small portable wireless *** patch antennas are connected together to form an array *** with the patch antenna,the array antenna has a higher directivity gain and can achieve better transmission *** this project,I will test the single patch antenna first,and then move to 2×1 antenna ***,built a 2×2 antenna array,test and record their performance respectively.

关键词： Antenna gain Antenna efficiency Directivity Return loss Transmission loss Far-field Radiation pattern

Impact of Photovoltaics

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Modern Electronic Technology 2021年第1期5卷 5-9页

作者： zhihan zhang Qiaoyu Wang Demou Cao Kai Kang Electrical and Computer Systems Engineering Department Monash UniversityMelbourneVictoriaAustralia

Photovoltaics(PV)can convert sunlight into electricity by making use of the photovoltaic *** panels consist of photovoltaic cells made of semiconductor materials(such as silicon)to utilise the photovoltaic effect and convert sunlight into direct current(DC)***,PV has become the cheapest electrical power source with low price bids and low panel *** competitiveness makes it a potential path to mitigate the global *** this paper,we investigate the relationship of PC array output with irradiance and temperature,the performance of PV array over 24 hours period,and the simulation of PV micro grid by MATLAB simulation.

关键词： Photovoltaics Array Irradiance Temperature Microgrid Simulation