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Analytical Solutions of Cracks Emanating from an Elliptic Hole in an Infinite Plate under Tension

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Chinese Journal of Mechanical Engineering 2014年第5期27卷 1057-1063页

作者： liu Shuhong duan Shijie Department of Engineering Mechanics Shijiazhuang Tiedao University The Key Laboratory for Health Monitoring and Control of Large Structures of Hebei Province Department of Adult Education Shijiazhuang Tiedao University

It is a common phenomenon that the cracks originating from a hole can cause structural damage in ***,the fracture mechanics studies of hole edge crack problems are not *** problem of an elliptical hole with two collinear edge cracks of unequal length in an infinite plate under uniform tension at infinity is *** on the complex variable method,the analytical solutions of stress functions and stress intensity factors are *** stress distribution along the axes and the edge of the elliptical hole is given *** numerical results show that there is obvious stress concentration near the hole and cracks,and the stresses tend to applied loads at distances far from the defect,which conform to Saint-Venant’s ***,the stress functions are proved to be *** special conditions,the present configuration becomes the Griffith crack,two symmetrical cracks emanating from an elliptical hole,two cracks of unequal length emanating from a circular hole,a crack at the edge of a circular hole,or a crack emanating from an elliptical *** with available results,stress intensity factors for these special shapes of ellipses and cracks show good *** stress intensity factor for two cracks of unequal length at the edge of an elliptical hole increases with the crack length and the major-to-minor axis ratio of the elliptical *** stress distribution in an infinite plate containing an elliptic hole with unsymmetrical cracks is given for the first time.

关键词： hole crack stress distribution stress intensity factor

Axial mechanical experiments of unbonded flexible pipes

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Petroleum Science 2020年第5期17卷 1400-1410页

作者： Jun-Peng liu Murilo Augusto Vaz Rong-qi Chen Meng-Lan duan Irving Hernandez College of Safety and Ocean Engineering China University of PetroleumBeijing 102249China Ocean Engineering Program Federal University of Rio de JaneiroRio de JaneiroBrazil Engineering and Construction Department China National Off shore Oil CorporationBeijing 100010China

Axial structural damping behavior induced by internal friction and viscoelastic properties of polymeric layers may have an inevitable influence on the global analysis of flexible *** order to characterize this phenomenon and axial mechanical responses,a full-scale axial tensile experiment on a complex flexible pipe is conducted at room temperature,in which oscillation forces at different frequencies are applied on the *** parameters to be identified are axial strains which are measured by three kinds of instrumentations:linear variable differential transformer,strain gauge and camera united particle-tracking *** corresponding plots of axial force versus axial elongation exhibit obvious nonlinear hysteretic ***,the loss factor related to the axial structural damping behavior is found,which increases as the oscillation loading frequency *** axial strains from the three measurement systems in the mechanical experiment indicate good agreement,as well as the values of the equivalent axial *** damping generated by polymeric layers is relatively smaller than that caused by friction ***,it can be concluded that friction forces maybe dominate the axial structural damping,especially on the conditions of high frequency.

关键词： Flexible pipes Hysteresis behavior Structural damping Mechanical experiment

Zwitterionic hyaluronic acid derivatives for co-delivery of both chemotherapeutic and nucleic acid drugs in breast cancer treatment

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Nano Research 2025年第1期18卷 607-617页

作者： Ruo-Lin Jiang Hui-Na liu Yu-Fan Yang Zhi-Cheng Zhang qi Dai Xiao-Yan Bao Lin-Jie Wu Ya-Xin qin Xin Tan Xiao-Yan Sun Xu-Fang Ying Zhi-qing Ben Min Han Institute of Pharmaceutics College of Pharmaceutical SciencesZhejiang UniversityHangzhou 310058China Department of Radiation Oncology Key Laboratory of Cancer Prevention and InterventionThe Second Affiliated HospitalCollege of MedicineZhejiang UniversityHangzhou 310058China Hangzhou Institute of Innovative Medicine Zhejiang UniversityHangzhou 310058China Jinhua Institute of Zhejiang University Jinhua 321299China National Key Laboratory of Advanced Drug Delivery and Release Systems Zhejiang UniversityHangzhou 310058China Polytechnic institute Zhejiang UniversityHangzhou 310015China

Traditionally,hyaluronic acid has been widely used for drug delivery,but the current application bottleneck is that hyaluronic acid is hydrophilic and electronegative,which makes it difficult to carry hydrophobic drugs and small interfering RNA(siRNA)with the same *** on previous studies,we designed and synthesized hyaluronic acid nanocarriers HA-spermine/N,N,N-trimethylcystamine/DOX-TPP(HSTD)for loading siRNA to overcome the problem of siRNA release caused by strong electrostatic ***,N,N,Ntrimethylcystamine in the carrier can be degraded by intracellular glutathione to completely and rapidly release siRNA,thus promoting ***,when codelivered with the chemotherapy drug doxorubicin(DOX),this novel nanocarrier showed promising synergy in inhibiting tumor growth.

关键词： zwitterionic hyaluronic acid N N N-trimethylcystamine small interfering RNA(siRNA) doxorubicin

Investigation of Anti-Plane Shear Behavior of a Piezoelectric Material Containing an Impermeable Edge Crack

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上海交通大学学报 2004年第Z2期38卷 124-129页

作者： Shijie duan Shuhong liu Jin liu School of Adult Education Shijiazhuang Railway InstituteShijiazhuang 050043 China Department of Mechanics and Engineering Science Shijiazhuang Railway InstituteShijiazhuang 050043 China Department of Mechanics and Engineering Science Shijiazhuang Railway InstituteShijiazhuang 050043 China

The problem involving an edge-crack in a rectangular material under the anti-plane mechanical loading and in-plane electric loading is analyzed under the impermeable conditions. By using the series expansion, the general solutions of electromechanical fields are obtained, which satisfied both governing equations and crack sufrace boundary conditions, and the unknown constants in which can be obtained by the boundary collocation method. Numerical results are given to show the effect of electromechanical interaction on energy release rate.

关键词： piezoelectric material mode-Ⅲ edge-crack intensity factor energy release rate boundary collocation method

Characters of surface deformation and surface wave in thermal capillary convection

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Science China(Technological Sciences) 2006年第5期49卷 601-610页

作者： duan Li KANG qi HU Wenrei National Microgravity Laboratory/CAS Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China National Microgravity Laboratory/CAS Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China National Microgravity Laboratory/CAS Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

In the field of fluid mechanics, free surface phenomena is one of the mostimportant physical processes. In the present research work, the surface deformation and surface wavecaused by temperature difference of sidewalls in a rectangular cavity have been investigated. Thehorizontal cross-section of the container is 52 mmx42 mm, and there is a silicon oil layer of height3.5 mm in the experimental cavity. Temperature difference between the two side walls of the cavityis increased gradually, and the flow on the liquid layer will develop from stable convection toun-stable convection. An optical diagnostic system consisting of a modified Michelson interferometerand image processor has been developed for study of the surface deformation and surface wave ofthermal capillary convection. The Fourier transformation method is used to interferometer fringeanalysis. The quantitative results of surface deformation and surface wave have been calculated froma serial of the interference fringe patterns. The characters of surface deformation and surfacewave have been obtained. They are related with temperature gradient and surface tension. Surfacedeformation is fluctuant with time, which shows the character of surface wave. The cycle period ofthe wave is 4.8 s, and the amplitudes are from 0 to 0.55 mu m The phase of the wave near the coolside of the cavity is opposite and correlative to that near the hot side. The present experimentproves that the surface wave of thermal capillary convection exists on liquid free surface, and itis wrapped in surface deformation.

关键词： surface deformation, surface wave, thermocapillary convection, buoyancy convection, optical interferometer.

Attitude and Orbit Optimal Control of Combined Spacecraft via a Fully-Actuated System Approach

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Journal of Systems Science & Complexity 2022年第2期35卷 623-640页

作者： duan Guangquan liu Guo-Ping Center for Control Theory and Guidance Technology Harbin Institute of TechnologyHarbin 150001China Department of Electronic and Electrical Engineering Southern University of Science and TechnologyShenzhen 518055China

This paper investigates the attitude and orbit control for the combined spacecraft formed after a target spacecraft without the autonomous control ability is captured by a service *** optimal controller of fully-actuated system is proposed to realize the attitude and orbit stabilization control of combined *** stability of the system is proved by introducing Lyapunov *** simulation of the combined spacecraft and physical experiment based on the combined spacecraft simulator(CSS)are *** simulation and experiment results demonstrate the effectiveness and practicability of the optimal controller of fully-actuated system.

关键词： Attitude control combined spacecraft fully-actuated system optimal controller orbit control

Weakly k-hyponormal and polynomially hyponormal commuting operator pairs

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Science China Mathematics 2015年第2期58卷 405-422页

作者： duan Yong Jiang qi Ting Ting School of Mathematics and Statistics Northeast Normal University

We introduce the notion of weak k-hyponormality and polynomial hyponormality for commuting operator pairs on a Hilbert space and investigate their relationship with k-hyponormality and *** provide examples of 2-variable weighted shifts which are weakly 1-hyponormal but not *** relating the weak k-hyponormality and k-hyponormality of a commuting operator pair to positivity of restriction of some linear functionals to corresponding cones of functions,we prove that there is an operator pair that is polynomially hyponormal but not 2-hyponormal,generalizing Curto and Putinar’s result(1991,1993)to the two-variable case.

关键词： weakly k-hyponormal k-hyponormal polynomially hyponormal subnormal commuting operator pair

Direction navigability analysis of geomagnetic field based on Gabor filter

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Journal of Systems Engineering and Electronics 2018年第2期29卷 378-385页

作者： XIAO Jing duan Xiusheng qi Xiaohui WANG Jianchen Army Engineering University Shijiazhuang 050003China Government Representative Office Northwestern Polytechnical UniversityXi’an 710065China

Direction navigability analysis is a supplement to the navigability analysis theory, in which extraction of the direction suitable-matching features(DSMFs) determines the evaluation performance. A method based on the Gabor filter is proposed to estimate the direction navigability of the geomagnetic field. First,the DSMFs are extracted based on the Gabor filter’s ***, in the view of pattern recognition, the classification accuracy in fault diagnosis is introduced as the objective function of the hybrid particle swarm optimization(HPSO) algorithm to optimize the Gabor filter’s parameters. With its guidance, the DSMFs are extracted. Finally, a direction navigability analysis model is established with the support vector machine(SVM), and the performances of the models under different objective functions are discussed. Simulation results show the parameters of the Gabor filter have a significant influence on the DSMFs, which, in turn, affects the analysis results of direction navigability. Moreover, the risk of misclassification can be effectively reduced by using the analysis model with optimal Gabor filter parameters. The proposed method is not restricted in geomagnetic navigation, and it also can be used in other fields such as terrain matching and gravity navigation.

关键词： geomagnetic navigation navigability analysis direction navigability Gabor filter direction suitable-matching feature

Regioselective C-C bond cleavage/aminocarbonylation cascade under copper catalysis

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Science China Chemistry 2024年第11期67卷 3798-3806页

作者： qi-Chao Shan Yan Zhao Yong Wu Hong-Fei liu Xin-Hua duan Li-Na Guo Department of Chemistry School of ChemistryEnergy Research Center of Energy Storage Materials and DevicesMinistry of EducationXi’an Jiaotong UniversityXi’an 710049China State Key Laboratory of Applied Organic Chemistry Lanzhou UniversityLanzhou 730000China

A regioselective C-C bond cleavage/aminocarbonylation cascade is presented. In recent years, tremendous progress has been made in the alkoxyl radical-mediated C-C bond cleavage of unstrained monocarbocycles. In contrast, the deconstruction and functionalization of bicyclic skeletons has been less developed and has mainly focused on the ring expansion process. Inspired by the aromatization-driven C-C bond cleavage, here we demonstrate a ring-opening/aminocarbonylation cascade under copper catalysis, in which the formation of a stable γ-lactam or succinimide skeleton reverses the selectivity of C-C cleavage. Remarkably, the photo and thermal assistance is not required when the succinimide skeleton is formed during the ring opening process. DFT calculations revealed that this unexpected ring-opening process is thermodynamically and kinetically favourable.

关键词： C-C bond cleavage controllable regioselectivity aminocarbonylation bicyclic alkoxy radical