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Synthesis of Organofluorine Compounds with Acylsilanes

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Chinese Journal of Chemistry 2024年第8期42卷 887-902页

作者： Youyuan Guo Gang Zhou Xiao shen The Institute for Advanced Studies Engineering Research Center of Organosilicon Compounds&MaterialsMinistry of EducationWuhan University299 Bayi RoadWuhanHubei430072 China

Comprehensive Summary,Organofluorine compounds are central in synthetic chemistry,medicinal chemistry and material *** this review,we summarize the investigations on the synthesis of organofluorine compounds with *** the non-fluorinated acylsilanes,the in situ generation of difluoroenoxysilanes from the reactions of the acylsilanes with trifluoromethylation reagents is the major pathway,leading to the facile preparation of variousα,α-*** the fluoroalkylacylsilanes,apart from the in situ generation of difluoroenoxysilanes through anion Brook rearrangement,radical Brook rearrangement of the photoexcited acylsilanes and the selective control of reactivities of the biradicals pave the way for the synthesis of a variety of organofluorine *** general,most of these reactions gave racemic products,and the asymmetric synthesis of organofluorine compounds with acylsilanes is still rare,which would be a future.

关键词： Acylsilanes Organofluorine compounds Brook rearrangement Radical rearrangement β-Fluoride elimination Asymmetric catalysis Photocatalysis Defluoroalkylation

Stability Investigation and Improvement for DC Cascade Systems with Simplified Impedance-based Stability Criterion

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1044-1052页

作者： Junbin Fang Zhikang Shuai Yang Li Zhibing Wang Xiangyang Wu Xia shen Z.John shen College of Electrical and Information Engineering Hunan UniversityChangsha 410082China Renewable Energy Department of China Electric Power Research Institute Beijing 100192China Department of Electrical and Computer Engineering Illinois Institute of TechnologyChicagoIL 60616USA IEEE

In DC distributed power systems(DPSs),the complex impedance interactions possibly lead to DC bus voltage oscillation or *** previous research,the stability analysis of DPSs is implemented based on mathematical analysis in control *** specific mechanisms of the instability of the cascade system have not been intuitively *** this paper,the stability analysis of DPSs based on the traditional Nyquist criterion is simplified to the resonance analysis of the seriesconnected port impedance(Z=R+jX)of source and load *** reveals that the essential reason for impedance instability of a DC cascade system is that the negative damping characteristic(R<0)of the port the overall impedance amplifies the internal resonance source at reactance zero-crossing *** simplified stability criterion for DC cascade systems can be concluded as:in the negative damping frequency ranges(R<0),there exists no zero-crossing point of the reactance component(i.e.,X=0).According to the proposed stability criterion,the oscillation modes of cascade systems are classified.A typical one is the internal impedance instability excited by the negative damping,and the other one is that the external disturbance amplified by negativity in a low stability ***,the impedance reshaping method for stability improvement of the system can be further *** validity of the simplified criterion is verified theoretically and experimentally by a positive damping reshaping method.

关键词： DC cascaded system,impedance model impedance reconstruction stability criterion

Recent Advances in Enantioselective Reactions of Terminal Unactivated Alkenes

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Chinese Journal of Chemistry 2024年第7期42卷 760-776页

作者： Qihang Guo Xuzhong shen Zhan Lu Centerof ChemistryforFrontier Technologies Departmentof ChemistryZhejiang UniversityHangzhouZhejiang 310058China ZJU-Hangzhou Global Scientific and Technological Innovation Center HangzhouZhejiang 311215China College of Chemistry Zhengzhou UniversityZhengzhouHenan 450001China

α-Olefins as aliphatic terminal alkenes could be obtained easily from numerous contemporary synthetic reactions as well as petro-chemical industry,and also found in natural *** to the alkenes attaching the directing groups or activating group,the catalytic asymmetric reaction of unactivated terminal alkenes presents great challenges due to the weak electron effect and small steric hindrance *** review mainly summarizes the latest progress of the asymmetric reaction of unactivated terminal olefins since 2016.

关键词： Asymmetric catalysis Terminal unactivated alkenes Hydrofunctionalization Difunctionalization Metal-catalyzed

Study on vibration reduction of two-scale system coupled with dynamic vibration absorber

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Applied Mathematics and Mechanics(English Edition) 2024年第8期45卷 1335-1352页

作者： Honglin WAN Xianghong LI Yongjun shen Department of Mathematics and Physics Shijiazhuang Tiedao UniversityShijiazhuang 050043China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China School of Mechanical Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China

The dynamic vibration absorber with inerter and grounded stiffness(IGDVA)is used to control a two-scale system subject to a weak periodic *** vibration suppression effect is *** amplitude of the main system coupled with absorber is significantly reduced,and the high frequency vibration completely ***,through the slow-fast analysis and stability theory,it is found that the stability of the autonomous system exerts a notable regulating effect on the vibration response of the non-autonomous *** adding the dynamic vibrator absorber,the center in the autonomous system changes to an asymptotically stable focus,consequently suppressing the vibration in the non-autonomous *** research reveals that the parameters of the absorber affect the real parts of the eigenvalues of the autonomous system,thereby regulating the stability of the *** from a qualitative standpoint to a quantitative approach,a comparison of the solutions before and after the introduction of the dynamic absorber reveals that,when the grounded stiffness ratio and the mass ratio of the dynamic absorber are not equal,the high-frequency part in the analytical solution *** a result,this leads to a reduction in the amplitude of the trajectory,achieving a vibration reduction effect.

关键词： two-scale system dynamic vibration absorber vibration control inerter

Impact of High Sodium Diet on Neovascularization and Osseointegration around Titanium Implant:An in Vivo and in Vitro Study

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Biomedical and Environmental Sciences 2024年第7期37卷 739-753页

作者： Keyuan Xu Xiaoting Tang Yun Xiang Yiding shen Zhennan Deng Pingping Ma Xinkun shen Department of Orthopaedics The Third Affiliated Hospital of Wenzhou Medical University(Ruian People’s Hospital)Wenzhou 325016ZhejiangChina School and Hospital of Stomatology Wenzhou Medical UniversityWenzhou 325027ZhejiangChina

Objective A high sodium(HS)diet is believed to affect bone metabolism *** its impact on osseointegration of titanium(Ti)implants holds significant implications for postoperative dietary management of implanted *** This investigation probed the impact of sodium ions(Na^(+))on neovascularization and osteogenesis around Ti implants in vivo,utilizing micro-computed tomography,hematoxylin and eosin staining,and immunohistochemical ***,in vitro experiments assessed the effects of varied Na^(+)concentrations and exposure durations on human umbilical vein endothelial cells(HUVECs)and MC3T3-E1 *** In vivo,increased dietary sodium(0.8%-6.0%)led to a substantial decline in CD34 positive HUVECs and new bone formation around Ti implants,alongside an increase in inflammatory *** vitro,an increase in Na^(+)concentration(140-150 mmol/L)adversely affected the proliferation,angiogenesis,and migration of HUVECs,especially with prolonged *** MC3T3-E1 cells initially exhibited less susceptibility to high Na^(+)concentrations compared to HUVECs during short-term exposure,prolonged exposure to a HS environment progressively diminished their proliferation,differentiation,and osteogenic *** These findings suggest that HS diet had a negative effect on the early osseointegration of Ti implants by interfering with the process of postoperative vascularized bone regeneration.

关键词： High-sodium Implants Vascularization Osseointegration

Analytical computation of magnetic field in coil-dominated superconducting quadrupole magnets based on racetrack coils

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Nuclear Science and Techniques 2024年第4期35卷 119-135页

作者： Chuang shen Ying-Shun Zhu Fu-San Chen China Spallation Neutron Source Institute of High Energy PhysicsChinese Academy of Sciences1 Zhongziyuan RoadDongguan 523000China Institute of High Energy Physics Chinese Academy of Sciences19B Yuquan RoadBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China

Currently,three types of superconducting quadrupole magnets are used in particle accelerators:cos 2θ,CCT,and ***,all three coil configurations have complex spatial geometries,which make magnet manufacturing and strain-sensitive superconductor applications *** with the three existing quadrupole coils,the racetrack quadrupole coil has a simple shape and manufacturing process,but there have been few theoretical *** this paper,the two-dimensional and three-dimensional analytical expressions for the magnetic field in coil-dominated racetrack superconducting quadrupole magnets are *** analytical expressions of the field harmonics and gradient are fully resolved and depend only on the geometric parameters of the coil and current ***,a genetic algorithm is applied to obtain a solution for the coil geometry parameters with field harmonics on the order of 10^(-4).Finally,considering the practical engineering needs of the accelerator interaction region,electromagnetic design examples of racetrack quadrupole magnets with high gradients,large apertures,and small apertures are described,and the application prospects of racetrack quadrupole coils are analyzed.

关键词： Superconducting quadrupole magnet Racetrack coil Multipole field Genetic algorithm Magnetic design

A Coordinate-Free Approach to the Design of Generalized Griffis-Duffy Platforms

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 95-103页

作者： Chengwei shen Xu Pei Lubin Hang Jingjun Yu College of Optical Mechanical and Electrical EngineeringZhejiang A&F UniversityHangzhou 311300China School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China School of Mechanical and Automotive Engineering Shanghai University of Engineering ScienceShanghai 201620China

Architectural singularity belongs to the Type II singularity,in which a parallel manipulator(PM)gains one or more degrees of freedom and becomes *** remaining permanently in a singularity are beneficial for linearto-rotary motion ***-Duffy(GD)platform is a mobile structure admitting a Bricard *** this paper,we present a coordinate-free approach to the design of generalized GD platforms,which consists in determining the shape and attachment of both the moving platform and the fixed *** generalized GD platform is treated as a combination of six coaxial single-loop mechanisms under the same *** to the inversion,hidden in the geometric structure of these single-loop mechanisms,the mapping from a line to a circle establishes the geometric transformation between the fixed base and the moving platform based on the center of inversion,and describes the shape and attachment of the generalized GD ***,the center of inversion not only identifies the location of rotation axis,but also affects the shape of the platform mechanism.A graphical construction of generalized GD platforms using inversion,proposed in the paper,provides geometrically feasible solutions of the manipulator design for the requirement of the location of rotation axis.

关键词： Generalized Griffis-Duffy platforms Self-motion Inversion Coordinate-free determination Manipulator design

Research Progress on Bionic Water Strider Robots

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Journal of Bionic Engineering 2024年第2期21卷 635-652页

作者： Jianhao Liu Mingjun shen Ziqiang Ma Xinping Zhou School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan430074China State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan430074China

Biological water striders have advantages such as flexible movement,low disturbance to the water surface,and low *** have developed a large number of biomimetic water strider robots based on their movement mechanism,which have broad application prospects in water quality testing,water surface reconnaissance,and *** article mainly reviews the research progress of biomimetic water strider ***,the biological and kinematic characteristics of water striders are outlined,and some mechanical parameters of biological water striders are *** basic equations of water strider movement are then ***,an overview is given of the past and current work on skating and jumping movements of biomimetic water strider robots based on surface tension and water pressure *** on the current research status of biomimetic water strider robots,the shortcomings of current research on biomimetic water striders are summarized,and the future development of biomimetic water strider robots is *** article provides new insights for the design of biomimetic water strider robots.

关键词： Bionics Water strider Robot Motion of robots on water surface

Exploring the potential of olivine-containing copper-nickel slag for carbon dioxide mineralization in cementitious materials

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 562-573页

作者： Qianqian Wang Zequn Yao Lijie Guo Xiaodong shen College of Materials Science and Engineering Nanjing Tech UniversityNanjing 211816China State Key Laboratory of Materials-Oriented Chemical Engineering Nanjing 211816China BGRIMM Technology Group Beijing 100160China

Water-quenched copper-nickel metallurgical slag enriched with olivine minerals exhibits promising potential for the production of CO_(2)-mineralized cementitious *** this work,copper-nickel slag-based cementitious material(CNCM)was synthesized by using different chemical activation methods to enhance its hydration reactivity and CO_(2) mineralization *** water curing ages and carbonation conditions were explored related to their carbonation and mechanical properties ***,thermogravimetry differential scanning calorimetry and X-ray diffraction methods were applied to evaluate the CO_(2) adsorption amount and carbonation products of *** development of carbonated CNCM blocks was examined by backscattered electron imaging(BSE)with energy-dispersive X-ray *** showed that among the studied samples,the CNCM sample that was subjected to water curing for 3 d exhibited the highest CO_(2) sequestration amount of 8.51wt%at 80℃and 72 h while presenting the compressive strength of 39.07 *** result indicated that 1 t of this CNCM can sequester 85.1 kg of CO_(2) and exhibit high compressive *** the addition of citric acid did not improve strength development,it was beneficial to increase the CO_(2) diffusion and adsorption amount under the same carbonation conditions from BSE *** work provides guidance for synthesizing CO_(2)-mineralized cementitious materials using large amounts of metallurgical slags containing olivine minerals.

关键词： copper-nickel slag fayalite CO_(2)sequestration cementitious material admixtures carbonation conditions