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Modified super twisting controller for servicing to uncontrolled spacecraft

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Journal of Systems Engineering and Electronics 2015年第2期26卷 334-345页

作者： Binglong Chen Yunhai Geng research center of Satellite technology Harbin Institute of Technology

A relative position and attitude coupled sliding mode controller is proposed by combining the standard super twisting （ST） control and basic linear algorithm for autonomous rendezvous and docking. It is schemed for on-orbit servicing to a tumbling non- cooperative target spacecraft subjected to external disturbances. A coupled dynamic model is established including both kinemati- cal and dynamic coupled effect of relative rotation on relative translation, which illustrates the relative movement between the docking port located in target spacecraft and another in service spacecraft. The modified super twisting （MST） control algorithm containing linear compensation items is schemed to manipulate the relative position and attitude synchronously. The correction provides more robustness and convergence velocity for dealing with linearly growing perturbations than the ST control algorithm. Moreover, the stability characteristic of closed-loop system is ana- lyzed by Lyapunov method. Numerical simulations are adopted to verify the analysis with the comparison between MST and ST control algorithms. Simulation results demonstrate that the pro- posed MST controller is characterized by high precision, strong robustness and fast convergence velocity to attenuate the linearly increasing perturbations.

关键词： autonomous rendezvous and docking coupled dynamic model modified super twisting Lyapunov method

Metabolic reprogramming: a new option for the treatment of spinal cord injury

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Neural Regeneration research 2025年第4期20卷 1042-1057页

作者： Jiangjie Chen Jinyang Chen Chao Yu Kaishun Xia Biao Yang Ronghao Wang Yi Li Kesi Shi Yuang Zhang Haibin Xu Xuesong Zhang Jingkai Wang Qixin Chen Chengzhen Liang Department of Orthopedics The Second Affiliated Hospital of Zhejiang University School of MedicineHangzhouZhejiang ProvinceChina Orthopedics research Institute of Zhejiang University Zhejiang UniversityHangzhouZhejiang ProvinceChina Key Laboratory of Motor System Disease research and Precision Therapy of Zhejiang Province HangzhouZhejiang ProvinceChina Clinical research center of Motor System Disease of Zhejiang Province HangzhouZhejiang ProvinceChina Qiandongnan Prefecture People’s Hospital KailiGuizhou ProvinceChina Department of Orthopedics Fourth Medical CenterChinese PLA General HospitalBeijingChina

Spinal cord injuries impose a notably economic burden on society,mainly because of the severe after-effects they *** the ongoing development of various therapies for spinal cord injuries,their effectiveness remains ***,a deeper understanding of metabolism has opened up a new therapeutic opportunity in the form of metabolic *** this review,we explore the metabolic changes that occur during spinal cord injuries,their consequences,and the therapeutic tools available for metabolic *** spinal cord metabolism is characterized by independent cellular metabolism and intercellular metabolic ***,spinal cord injury results in metabolic disorders that include disturbances in glucose metabolism,lipid metabolism,and mitochondrial *** metabolic disturbances lead to corresponding pathological changes,including the failure of axonal regeneration,the accumulation of scarring,and the activation of *** rescue spinal cord injury at the metabolic level,potential metabolic reprogramming approaches have emerged,including replenishing metabolic substrates,reconstituting metabolic couplings,and targeting mitochondrial therapies to alter cell *** available evidence suggests that metabolic reprogramming holds great promise as a next-generation approach for the treatment of spinal cord *** further advance the metabolic treatment of the spinal cord injury,future efforts should focus on a deeper understanding of neurometabolism,the development of more advanced metabolomics technologies,and the design of highly effective metabolic interventions.

关键词： axons glycolysis metabolic reprogramming metabolism mitochondria neural regeneration neuroprotection oxidative phosphorylation spinal cord injury therapy

research status and prospects of the fractal analysis of metal material surfaces and interfaces

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 20-38页

作者： Qinjin Dai Xuefeng Liu Xin Ma Shaojie Tian Qinghe Cui Beijing Advanced Innovation center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China Beijing Laboratory of Metallic Materials and Processing for Modern Transportation University of Science and Technology BeijingBeijing 100083China Laboratory for Advanced Materials Processing of Ministry of Education University of Science and Technology BeijingBeijing 100083China School of Mechanical and Electrical Engineering Xinjiang Institute of EngineeringUrumqi 830023China

As a mathematical analysis method,fractal analysis can be used to quantitatively describe irregular shapes with self-similar or self-affine *** analysis has been used to characterize the shapes of metal materials at various scales and *** methods make it difficult to quantitatively describe the relationship between the regular characteristics and properties of metal material surfaces and ***,fractal analysis can be used to quantitatively describe the shape characteristics of metal materials and to establish the quantitative relationships between the shape characteristics and various properties of metal *** the perspective of two-dimensional planes and three-dimensional curved surfaces,this paper reviews the current research status of the fractal analysis of metal precipitate interfaces,metal grain boundary interfaces,metal-deposited film surfaces,metal fracture surfaces,metal machined surfaces,and metal wear *** relationship between the fractal dimensions and properties of metal material surfaces and interfaces is *** from three perspectives of fractal analysis,namely,research scope,image acquisition methods,and calculation methods,this paper identifies the direction of research on fractal analysis of metal material surfaces and interfaces that need to be *** is believed that revealing the deep influence mechanism between the fractal dimensions and properties of metal material surfaces and interfaces will be the key research direction of the fractal analysis of metal materials in the future.

关键词： metal material surfaces and interfaces fractal analysis fractal dimension homogeneity

Three-dimensional fracture of UO2 ceramic pellets by phase field modeling

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 169-180页

作者： Wei Xiong Xuan Ye Hongzhang Cheng Xiaoming Liu Institute of Nuclear and New Energy technology Collaborative Innovation Center of Advanced Nuclear Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education Tsinghua University State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences School of Engineering Science University of Chinese Academy of Sciences

Fracture is the primary failure type for the UO2ceramic pellets,which are operated under irradiation and thermal processes,and physically confined by the *** this work,by combining closely coupled physical processes of heat conduction,heat transfer,and mechanical deformation with the cohesive phase field framework,we proposed a high-precision modeling of quasistatic cracking of three-dimensional （3D） UO2ceramic fuel pellets under high temperature and *** simulation results agree well with the experimental results,indicating that the proposed method has the potential to capture 3D crack modes in the interested time ***,we studied the relation of the 3D fracture patterns of fuel pellets with the peak power *** was found that the power level plays a critical role in determining the competition between radial and circumferential cracks,as well as transverse penetrating cracks.

关键词： phase field method nuclear fuel pellet coupled thermo-mechanical model thermal fracture

Integrated modeling of spacecraft relative motion dynamics using dual quaternion

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Journal of Systems Engineering and Electronics 2018年第2期29卷 367-377页

作者： PENG Xuan SHI Xiaoping GONG Yupeng Control and Simulation center Harbin Institute of Technology research center of Satellite technology Harbin Institute of Technology

To realize high accurate control of relative position and attitude between two spacecrafts, the coupling between position and attitude must be fully considered and a more precise model should be established. This paper breaks the traditional divide and conquer idea, and uses a mathematical tool, namely dual quaternion to establish the integrated 6 degree-of-freedom(6-DOF) model of relative position and attitude, which describes the coupled relative motion in a compact and efficient form and needs less information of the target. Considering the complex operation rules and the unclarity of the current relative motion model in dual quaternion, necessary mathematical foundations are given at first, followed by clear and detailed modeling process and analysis. Finally a generalized proportion-derivative(PD) controller law is designed. The simulation results show that based on the integrated model established by dual quaternion, this control law can achieve a high control accuracy of relative motion.

关键词： relative motion dual quaternion position and attitude coupling integrated modeling

Microstructure and Mechanical Properties of Hybrid Laser-Friction Stir Welding between AA6061-T6 Al Alloy and AZ31 Mg Alloy

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Journal of Materials Science & technology 2011年第3期27卷 199-204页

作者： Woong-Seong Chang S.R.Rajesh Chang-Keun Chun Heung-Ju Kim Welding research center Research Institute of Industrial Science and Technology

For the purpose of improving the strength of this dissimilarjoint, the present study was carried out to investigate the improvement in intermetallic layer by using a third material foil between the laying edges of the friction stir welded and hybrid welded AI6061-T6/AZ31 alloy plates. The difference in microstructural and mechanical characteristics of friction stir welded and hybrid welded AI6061-TO/AZ31 joint was compared. Hybrid butt- welding of aluminum alloy plate to a magnesium alloy plate was successfully achieved with Ni foil as filler material, while defect-free laser-friction stir welding （FSW） hybrid welding was achieved by using a laser power of 2 kW. Transverse tensile strength of the joint reached about 66% of the Mg base metal tensile strength in the case of hybrid welding with Ni foil and showed higher value than that of the friction stir welded joint with and without the third material foil. This may be due to the presence of less brittle Ni-based intermetallic phases instead of Al12Mg17.

关键词： Frictions stir welding Laser welding Dissimilar metal joint Hybrid welding Magnesium alloy Aluminum alloy

Prediction of Flowing Bottomhole Pressures for Two-Phase Coalbed Methane Wells

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Acta Geologica Sinica(English Edition) 2013年第5期87卷 1412-1420页

作者： LIU Xinfu technology research center CNOOC Research Institute

A method is proposed to predict the flowing bottomhole pressures （FBHPs） for two-phase coalbed methane （CBM） wells. The mathematical models for both gas column pressure and two-phase fluid column pressure were developed based on the well liquid flow equation. FBHPs during the production were predicted by considering the effect of entrained liquid on gravitational gradients. Comparison of calculated BHPs by Cullender-Smith and proposed method was also studied. The results show that the proposed algorithm gives the desired accuracy of calculating BHPs in the low- productivity and low-pressure CBM wells. FBHP is resulted from the combined action of wellhead pressure, gas column pressure and fluid column pressure. Variation of kinetic energy term, compressibility and friction factors with depth increments and liquid holdup with velocity should be considered to simulate the real BHPs adequately. BHP is a function of depth of each column segment. The small errors of less than 1.5% between the calculated and measured values are obtained with each segment within 25 m. Adjusting BHPs can effectively increase production pressure drop, which is beneficial to CBM desorption and enhances reservoir productivity. The increment of pressure drop from 5.37 MPa2 to 8.66 MPa2 leads to an increase of CBM production from 3270 m3/d to 6700 m3/d and is attributed to a decrease in BHP from 2.25 MPa to 1.33 MPa.

关键词： coalbed methane productivity flowing bottomhole pressure gas column pressure two-phase fluid column pressure

A new horizon for neuroscience:terahertz biotechnology in brain research

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Neural Regeneration research 2025年第2期20卷 309-325页

作者： Zhengping Pu Yu Wu Zhongjie Zhu Hongwei Zhao Donghong Cui Shanghai Key Laboratory of Psychotic Disorders Shanghai Mental Health CenterShanghai Jiao Tong University School of MedicineShanghaiChina Department of Psychiatry Kangci Hospital of JiaxingTongxiangZhejiang ProvinceChina Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghaiChina Key Laboratory of Interfacial Physics and technology Shanghai Institute of Applied PhysicsChinese Academy of ScienceShanghaiChina National Facility for Protein Science in Shanghai Shanghai Advanced Research InstituteChinese Academy of SciencesShanghaiChina

Terahertz biotechnology has been increasingly applied in various biomedical fields and has especially shown great potential for application in brain *** this article,we review the development of terahertz biotechnology and its applications in the field of *** evidence indicates promising prospects for the use of terahertz spectroscopy and terahertz imaging techniques in the diagnosis of amyloid disease,cerebrovascular disease,glioma,psychiatric disease,traumatic brain injury,and myelin *** vitro and animal experiments have also demonstrated the potential therapeutic value of terahertz technology in some neuropsychiatric *** the precise underlying mechanism of the interactions between terahertz electromagnetic waves and the biosystem is not yet fully understood,the research progress in this field shows great potential for biomedical noninvasive diagnostic and therapeutic ***,the biosafety of terahertz radiation requires further exploration regarding its two-sided efficacy in practical *** review demonstrates that terahertz biotechnology has the potential to be a promising method in the field of neuropsychiatry based on its unique advantages.

关键词： biological effect brain neuron neuropsychiatry neuroscience non-thermal effect terahertz imaging terahertz radiation terahertz spectroscopy terahertz technology

Effect of cholesterol metabolism on hepatolithiasis

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World Journal of Gastroenterology 2025年第1期31卷 157-162页

作者： Lin Zheng Zi-Yu Ye Jun-Ji Ma Department of Gastroenterology The Second Hospital of Hebei Medical UniversityHebei Key Laboratory of GastroenterologyHebei Institute of GastroenterologyHebei Clinical Research Center for Digestive DiseasesNo.215 Heping West RoadShijiazhuang 050000Hebei ProvinceChina

Surgical intervention is currently the primary treatment for hepatolithiasis;how-ever,some patients still experience residual stones and high recurrence rates after *** metabolism seems to play an important role in hepatoli-thiasis pathogenesis.A high cholesterol diet is one of the significant reasons for the increasing incidence of ***,regular diet and appropriate medical intervention are crucial measures to prevent hepatolithiasis and reduce recurrence rate after *** dietary cholesterol and drugs that increase cholesterol stone solubility are key therapeutic approaches in treating *** article discusses the cholesterol metabolic pathways related to the pathogenesis of hepatolithiasis,as well as food intake and targeted therapeutic drugs.

关键词： Hepatolithiasis Cholesterol metabolism High-fat diet 3-hydroxy-3-methylglutaryl-coenzyme A reductase Interlobular bile duct