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Buckling analysis of planar linear uniform deployable structures consisting of scissor-like element in space under compression

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Science China(Technological Sciences) 2021年第3期64卷 493-507页

作者： LI Bo WANG SanMin tan u-xuan School of Mechanical and Precision Instrument Engineering Xi’an University of TechnologyXi’an 710048China Department of Engineering Product Development Singapore University of Technology and DesignSingapore 487372Singapore School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China

This paper comprehensively investigates the buckling load and the stability of a planar linear array deployable structure composed of scissor-like element(SLE)under *** present,the researches on deployable structure are mainly focused on configuration design and dynamics characteristics of the mechanisms,but less on structural *** fact,when the external load exceeds the structural critical load value,the deployable structure will be permanently deformed or even collapse directly and no longer have any bearing *** address this issue,a new stability model is derived using linear elastic analysis method and substructure method to evaluate the buckling characteristics of the deployable structure with n SLEs when it is carried out in space,which can accurately obtain the structural instability load and can be used quantitatively to optimize the structure for making it have the most stable *** addition,the effects of the number of elements,the length,material properties and flexibility of the bar,and the deployment degree on the buckling of the scissor deployable structure are investigated,and the results of the theoretical analysis are compared with simulation and analytical results,respectively,confirming that the proposed stability model not only is able to effectively predict the structural instability load but also determine which part of the deployable structure is *** can be concluded that the stability of the deployable structure gradually decreases with the increase of the number of elements or the bar *** the calculation process,the critical load of each sub-element should be considered,and the minimum value of the critical loads of all subunits can be regarded as the instability load of the whole structure.

关键词： deployable structure stability analysis buckling load sub structure linear array simulation

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太空中平面线性均匀剪式单元可展结构受压状况下的屈曲分析

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中国科学：技术科学 2020年第11期50卷 1529-1530页

作者：李博王三民 tan u-xuan 西安理工大学机械与精密仪器工程学院西安710048 新加坡科技设计大学工业产品开发新加坡487372 西北工业大学机电学院西安710072

可展结构是一种同时具有机构和结构特性的复杂的组合结构,因其具有形态可变、可拆卸、易组装等特点而被广泛研究.本研究中的可展结构是由‘X’形状的剪式单元线性阵列组装而成,其中每个单元由两个杆件经过枢轴铰接而成,并且不同单元间... 详细信息

可展结构是一种同时具有机构和结构特性的复杂的组合结构,因其具有形态可变、可拆卸、易组装等特点而被广泛研究.本研究中的可展结构是由‘X’形状的剪式单元线性阵列组装而成,其中每个单元由两个杆件经过枢轴铰接而成,并且不同单元间在端点处相互连接,具有收缩率大、展开动作可靠、高精度和高刚度的特点.根据工程需要,各个子单元间可以通过不同的连接方式组装成不同的构型,如线性可展结构、环形可展结构等.目前该机构已经引起了生物机构、建筑、航空航天等多个领域专家学者的兴趣.

关键词：可展结构组合结构剪式单元航空航天线性阵列子单元屈曲分析高刚度

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Highly coupled off-resonance lattice design in diffraction-limited light sources

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Nuclear Science and Techniques 2024年第9期35卷 92-102页

作者： Yi-Hao Gong Shun-Qiang Tian Xin-Zhong Liu Shou-Zhi xuan Li-Yuan tan Ling-Long Mao Shanghai Advanced Research Institute Chinese Academy of Sciences Shanghai 201204 ShanghaiChina Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 ShanghaiChina university of Chinese Academy of Sciences 100049 BeijingChina

The round-beam operation presents many benefits for scientific experiments regarding synchrotron radiation and the weak-ening influences of intra-beam scattering in diffraction-limited synchrotron light sources.A round-beam generation method based on the global setting of skew quadrupoles and the application of a non-dominated sorting genetic algorithm was pro-posed in this *** schemes,including large-emittance coupling introduced via betatron coupling and vertical disper-sion,were explored in a candidate lattice for an upgrade-proposal of the Shanghai synchrotron radiation *** variations with lattice imperfections and their influence on the beam dynamics of beam optic distortions were *** results demonstrated that a precise coupling control ranging from 10 to 100%was achieved under low optical distortion,whereas full-coupling generation and its robustness were achieved by our proposed method by adjusting the skew quadrupole components located in the dispersion-free *** Touschek lifetime increased by a factor of 2–2.5.

关键词： Diffraction-limited storage ring(DLSR) Shanghai synchrotron radiation facility upgrade(SSRF-u) Round beam Off-resonance coupling

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A Review on Vibration Control of Multiple Cylinders Subjected to FlowInduced Vibrations

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China Ocean Engineering 2024年第2期38卷 183-197页

作者： Xu Wan-hai MA Ye-xuan State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation Tianjin UniversityTianjin 300350China Institute of Mechanics Chinese Academy of SciencesBeijing 100190China

The fatigue damage caused by flow-induced vibration(FIV)is one of the major concerns for multiple cylindrical structures in many engineering *** FIV suppression is of great importance for the security of many cylindrical *** active and passive control methods have been employed for the vibration suppression of an isolated cylinder undergoing vortex-induced vibrations(VIV).The FIV suppression methods are mainly extended to the multiple cylinders from the vibration control of the isolated *** to the mutual interference between the multiple cylinders,the FIV mechanism is more complex than the VIV mechanism,which makes a great challenge for the FIV *** efforts have been devoted to vibration suppression of multiple cylinder systems undergoing FIV over the past two *** control methods,such as helical strakes,splitter plates,control rods and flexible sheets,are not always effective,depending on many influence factors,such as the spacing ratio,the arrangement geometrical shape,the flow velocity and the parameters of the vibration control *** FIV response,hydrodynamic features and wake patterns of the multiple cylinders equipped with vibration control devices are reviewed and *** FIV suppression efficiency of the vibration control methods are analyzed and compared considering different influence *** research on the FIV suppression of multiple cylinders is suggested to provide insight for the development of FIV control methods and promote engineering applications of FIV control methods.

关键词： flow-induced vibration vibration control multiple cylinders tandem side-by-side staggered

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Comparative analysis between single-train passing and double-train intersection in a tunnel

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Journal of Zhejiang university-Science A(Applied Physics & Engineering) 2024年第5期25卷 429-442页

作者： Jianming Du Qian FANG xuan ZHANG Hualao WANG Bridge and Tunnel Research Center Research Institute of Highway Ministry of TransportBeijing 100088China Tunnel and underground Engineering Research Center of Ministry of Education Beijing Jiaotong UniversityBeijing 00044China

Aerodynamic pressure significantly impacts the scientific evaluation of tunnel service *** aerodynamic pressure of two trains running in a double-track tunnel is considerably more complicated than that of a single *** used the numerical method to investigate the difference in aerodynamic pressure between a single train and two trains running in a double-track ***,the numerical method was verified by comparing the results of numerical simulation and on-site ***,the characteristics of aerodynamic pressure were ***,the influence of various train-tunnel factors on the characteristics of aerodynamic pressure was *** results show that the aerodynamic pressure variation can be divided into stage I:irregular pressure fluctuations before the train tail leaves the tunnel exit,and stage II:periodic pressure declines after the train tail leaves the tunnel *** addition,the aerodynamic pressure simultaneously jumps positively or drops negatively for a single train or two trains running in double-track tunnel *** pressure amplitude in the two-train case is higher than that for a single *** maximum positive peak pressure difference(P_(STP))and maximum negative peak pressure difference(P_(STN))increase as train speed rises to the power from 2.256 to 2.930 in stage *** P_(STP) and P_(STN) first increase and then decrease with the increase of tunnel length in stage *** P_(STP) and P_(STN) increase as the blockage ratio rises to the power from 2.032 to 2.798 in stages I and II.

关键词： Railway tunnel Aerodynamic effect Pressure characteristic Train speed Tunnel length Blockage ratio

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Chiral thermally activated delayed fluorescence materials for circularly polarized organic light-emitting diodes

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Science China Chemistry 2024年第4期67卷 1097-1116页

作者： Li Yuan Yi-Pin Zhang You-xuan Zheng State Key Laboratory of Coordination Chemistry Collaborative Innovation Center of Advanced MicrostructuresJiangsu Key Laboratory of Advanced Organic MaterialsSchool of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China

Chirality is an important natural characteristic of organic molecules,and chiral organic molecules have shown extensive application in areas such as pharmaceutical development and material *** from the ability to achieve circularly polarized luminescence(CPL),chiral luminescent materials have shown potential applications in anti-glare display,optical communication and,3D display,*** to the ability to harvest both singlet and triplet excitons by a fast reverse intersystem crossing process without involving noble metals,chiral thermally activated delayed fluorescence(TADF)materials with point chirality,axial chirality,planar chirality and helical chirality are regarded as the state-of-the-art materials for circularly polarized organic light-emitting diodes(CP-OLEDs).In recent years,the chiral TADF materials and CP-OLEDs have rapidly developed,but unfortunately,the dissymmetry factors(g)are far from the requirement of practical *** ideal emitters and devices should have both high efficiency and a g factor,or at least a balance between these two *** review gives an overview of recent progress in chiral TADF materials,with a particular focus on the chiral skeleton,CPL property and device ***,the molecular design concept,device structure and methods to improve the g factors of chiral materials and CP-OLEDs are also discussed.

关键词： chiral thermally activated delayed fluorescence material chiral skeleton circularly polarized luminescence circularly polarized organic light-emitting diodes dissymmetry factor

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Laser Powder Bed Fusion of Beta-Type Titanium Alloys for Biomedical Application:A Review

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Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 17-28页

作者： xuan Luo Chao Yang Dongdong Li Lai-Chang Zhang State Key Laboratory of Materials Processing and Die&Mould Technology Huazhong University of Science and TechnologyWuhan430074China National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials Guangdong Provincial Key Laboratory for Processing and Forming of Advanced Metallic MaterialsSouth China University of TechnologyGuangzhou510640China Centre for Advanced Materials and Manufacturing School of EngineeringEdith Cowan University270 Joondalup DriveJoondalupPerthWA6027Australia

Additive manufacturing ofβ-type titanium alloy is expected to replace Ti-6Al-4V alloy in the field of orthopedic implantation because of their low elastic modulus,excellent corrosion resistance,and *** briefly introducing the laser powder bed fusion(LPBF)process and physical phenomena,this paper reviews the recent progresses in LPBF-edβ-type Ti *** strategies to strengthening and tougheningβ-type Ti alloys are critically *** is followed by the processing routes employed to achieve to low modulus for orthopedic applications,especially a new methodology for tailoring crystallographic orientation called multi-track coupled directional *** effect of processing and compositions on performance metrics ofβ-type Ti alloys included corrosion behavior,and biocompatibility is *** the end,challenges in additive manufacturing ofβ-type Ti alloys in future are highlighted,with the aim to ensue clinical application of LPBF-edβ-type Ti alloys.

关键词： β-type Ti alloys Laser powder bed fusion Mechanical properties Elastic modulus Biocompatibility

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Investigation of crack segmentation and fast evaluation of crack propagation, based on deep learning

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Frontiers of Structural and Civil Engineering 2024年第4期18卷 516-535页

作者： Than V.TRAN H.NGuYEN-xuan Xiaoying ZHuANG Institute of Photonics Leibniz University HannoverHannover 30167Germany CIRTech Institute HUTECH UniversityHo Chi Minh City 700000Vietnam College of Civil Engineering Tongji UniversityShanghai 200092China

Identifying crack and predicting crack propagation are critical processes for the risk assessment of engineering *** traditional approaches to crack modeling are faced with issues of high computational costs and excessive computing *** address this issue,we explore the potential of deep learning(DL)to increase the efficiency of crack detection and forecasting crack ***,there is no single algorithm that can fit all data sets well or can apply in all cases since specific tasks *** the paper,we present DL models for identifying cracks,especially on concrete surface images,and for predicting crack ***,SegNet and u-Net networks are used to identify concrete *** gradient descent(SGD)and adaptive moment estimation(Adam)algorithms are applied to minimize loss function during ***,time series algorithms including gated recurrent unit(GRu)and long short-term memory(LSTM)are used to predict crack *** experimental findings indicate that the u-Net is more robust and efficient than the SegNet for identifying crack segmentation and achieves the most outstanding *** evaluation of crack propagation,GRu and LSTM are used as DL models and results show good agreement with the experimental data.

关键词： deep learning crack segmentation crack propagation encoder−decoder recurrent neural network

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Meta-analysis of the clinical efficacy of the Gamma3 nail vs Gamma3u-blade system in the treatment of intertrochanteric fractures

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World Journal of Orthopedics 2024年第3期15卷 285-292页

作者： xuan Wu Bo Gao Department of Orthopedic Zhong Da HospitalSchool of MedicineSoutheast UniversityNanjing 210000Jiangsu ProvinceChina Department of Orthopedic The Affiliated Taizhou Second People's Hospital of Yangzhou UniversityTaizhou 225500Jiangsu ProvinceChina

BACKGROuND The traditional Gamma3 nail is a mainstream treatment for femoral intertrochanteric *** reports that the Gamma3u-blade system can increase the stability of the Gamma3 nail and reduce complication ***,comparative studies between the Gamma3u-blade and Gamma3 systems are limited;hence,this meta-analysis was performed to explore the clinical efficacy of these two surgical *** To investigate the clinical efficacy of Gamma3 and Gamma3 u-blade for intertrochanteric *** A computerized search for Chinese and English literature published from 2010 to 2022 was conducted in PubMed,Cochrane,CNKI,Wanfang,and VIP *** search keywords were gamma 3,gamma 3 u blade,and intertrochanteric ***,literature tracking was performed on the references of published *** data were analyzed using Revman 5.3 *** individuals checked the inputs for *** variables were described using mean difference and standard deviation,and outcome effect sizes were expressed using ratio OR and 95%confidence interval(CI).High heterogeneity was considered at(P50%),moderate heterogeneity at I2 from 25%to 50%,and low heterogeneity at(P≥0.05,I2uLTS Following a comprehensive literature search,review,and analysis,six articles were selected for inclusion in this *** selection comprised five articles in English and one in Chinese,with publication years spanning from 2016 to *** study with the largest sample size,conducted by Seungbae in 2021,included a total of 304 *** analysis:A total of 1063 patients were included in this *** main outcome indicators were:Surgical time:The Gamma3u blade system had a longer surgical time compared to Gamma3 nails(P=0.006,I2=76%).Tip-apex distance:No statistical significance or heterogeneity was observed(P=0.65,I2=0%).Harris Hip score:No statistical significance was found,and low heterogeneity was detected(P=0.

关键词： Gamma3 nail Gamma3u-Blade system Femoral intertrochanteric fractures Meta-analysis

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FuSE: a federated learning and u-shape split learning-based electricity theft detection framework

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Science China(Information Sciences) 2024年第4期67卷 339-340页

作者： xuan LI Naiyu WANG Liehuang ZHu Shuai YuAN Zhitao GuAN School of Control and Computer Engineering North China Electric Power University School of Cyberspace Science and Technology Beijing Institute of Technology Department of Finance Operationsand Information Systems(FOIS)Brock University

In recent years, the data-driven electricity theft detection methods integrated with edge cloud computing [1, 2] have not only demonstrated superior detection accuracy but also improved efficiency, making them viable alternatives to indoor inspections. Energy service providers(ESPs) typically manage regions by dividing them into various transformer districts(TDs). The detection of electricity theft in a particular region is performed by the associated TD,

关键词： Sensitive data

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