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Universal method for designing periodic orbits by homotopy classes in the elliptic restricted three-body problem

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Astrodynamics 2024年第1期8卷 175-188页

作者： Yue Zheng Min Zhao school of Electronic Engineering Xi’an Aeronautical InstituteXi’an710077China school of Aircraft Engineering Xi’an Aeronautical InstituteXi’an710077China school of Astronautics Northwestern Polytechnical UniversityXi’an710072China

The current methods for designing periodic orbits in the elliptic restricted three-body problem(ERTBP)have the disadvantages of targeting limited orbits and ergodic searches and considering only symmetric orbits.A universal method for designing periodic orbits is proposed in this ***,the homotopy classes of orbits are structured based on their topological ***,a dynamic model based on homotopy classes,ranging from the circular restricted three-body problem(CRTBP)to the ERTBP,can be built using the homotopy ***,a multi-and a single-period orbit were selected based on the resonance ***,the corresponding orbit in the ERTBP was computed by modifying the initial condition of the orbit in the *** method,without an ergodic search,can extend to any orbit,including an asymmetric orbit in the CRTBP,to the ERTBP model,and the two orbits are of the same homotopy *** of the Earth–Moon ERTBP are presented to verify the efficiency of this method.

关键词： periodic orbit elliptic restricted three-body problem(ERTBP) topology homotopy circular restricted three-body problem(CRTBP)

Research on the Dynamic Compressibility of Polyurethane Microcellular Elastomer and its Application for Impact Resistance

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Chinese Journal of Polymer Science 2024年第8期42卷 1185-1197页

作者： Zhi-Ying Zhao Hao Jiang Xiao-Dong Li Xu-Dong Zhang Xing Su Mei-Shuai Zou school of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China

The packaging materials with cushioning performance are used to prevent the internal contents from being damaged by the impact and vibration of external *** polyurethane microcellular elastomers(PUMEs)can absorb energy through cell collapse and molecular chain *** this study,PUMEs with different densities were investigated by scanning electron microscopy,dynamic mechanical analysis and dynamic compression *** exhibited significant im pact resistance and the maximum peak stress attenuation ratio reached 73.33%.The protective equipment was made by PUME with the optimal density of 600 kg/m^(3),and then the acceleration sensing device installed with the same protective equipment fell from a height of 3,5 and 10 m to evaluate the energy-absorbing property and reusability of *** results showed that PUMEs equipment reduced the peak acceleration of the device by 93.84%,with a maximum deviation of 9%between actual test and simulation,and shortened the impact time of first landing by 57.39%.In addition,the equipment PUMEs equipment could effectively reduce the stress on the protected items.

关键词： Polyurethane microcellular elastomer Impact velocity Stress attenuation ratio Impact resistance

Dispersion effect of nano-structure pyrolytic carbon on mechanical,electrical,and microstructural characteristics of cement mortar composite

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International Journal of Smart and Nano Materials 2024年第3期15卷 534-578页

作者： N.K.Karthikeyan S.Elavenil school of Civil Engineering Vellore Institute of TechnologyChennaiIndia

In material science,converting waste into nanomaterials by green technologies highlights the interest in producing sus-tainable carbon nanomaterial(SCN).This study first-ever uti-lized tyre-char as a Nano-Structure Pyrolytic Carbon(NSPC)to develop electrically conductive *** other car-bon nanomaterials,the efficiency of NSPC particle as an SCN in developing electrically conductive composites was investi-gated in terms of dispersion,mechanical,water absorption,electrical resistivity,and *** results of sedi-mentation and zeta potential(-19 mV)showed the excellent dispersion of NSPC particle in water with the combined effect of superplasticizer and *** compressive(40.37%)and flexural strength(10.76%)than that of plain cement mortar composite(CMC)is achieved with 2 wt.%and 1.5 wt.%of NSPC particle,*** water absorption rate and volume of permeable voids were reduced,exhibiting less *** percolation zone of AC and DC resis-tivity of NSPC composite ranges between 1 and 2 wt.%,and the established percolation threshold is at 2 wt.%.XRD analysis showed C-S-H formation consistently increased with curing age,and HR-SEM with EDAX analysis exhibits the dense micro-structure and well-distributed NSPC particle at the *** experimental outcomes significantly enhanced the relia-bility and provided a framework for tailoring NSPC particle as SCN for developing electrically conductive composite.

关键词： Sustainable nanomaterial dispersion mechanical properties electrical resistivity microstructure analysis

Improved spatio-temporal alignment measurement method for hull deformation

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Journal of Systems Engineering and Electronics 2024年第2期35卷 485-494页

作者： XU Dongsheng YU Yuanjin ZHANG Xiaoli PENG Xiafu school of Automation Beijing Institute of TechnologyBeijing 100081China school of Aerospace Engineering Xiamen UniversityXiamen 361005China

In this paper,an improved spatio-temporal alignment measurement method is presented to address the inertial matching measurement of hull deformation under the coexistence of time delay and large misalignment *** misalignment angle and time delay often occur simultaneously and bring great challenges to the accurate measurement of hull deformation in space and *** proposed method utilizes coarse alignment with large misalignment angle and time delay estimation of inertial measurement unit modeling to establish a brand-new spatiotemporal aligned hull deformation measurement *** addition,two-step loop control is designed to ensure the accurate description of dynamic deformation angle and static deformation angle by the time-space alignment method of hull *** experiments illustrate that the proposed method can effectively measure the hull deformation angle when time delay and large misalignment angle coexist.

关键词： inertial measurement spatio-temporal alignment hull deformation

Coordinated Dispatch Based on Distributed Robust Optimization for Interconnected Urban Integrated Energy and Transmission Systems

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 840-851页

作者： Wei Xu Yufeng Guo Tianhui Meng Yingwei Wang Jilai Yu the school of Electrical Engineering and Automation Harbin Institute of TechnologyHarbin 150001China

To improve the economic efficiency of urban integrated energy systems(UIESs)and mitigate day-ahead dispatch uncertainty,this paper presents an interconnected UIES and transmission system(TS)model based on distributed robust ***,interconnections are established between a TS and multiple UIESs,as well as among different UIESs,each incorporating multiple energy *** Bregman alternating direction method with multipliers(BADMM)is then applied to multi-block problems,ensuring the privacy of each energy system operator(ESO).Second,robust optimization based on wind probability distribution information is implemented for each ESO to address dispatch *** column and constraint generation(C&CG)algorithm is then employed to solve the robust ***,to tackle the convergence and practicability issues overlooked in the existing studies,an external C&CG with an internal BADMM and corresponding acceleration strategy is ***,numerical results demonstrate that the adoption of the proposed model and method for absorbing wind power and managing its uncertainty results in economic benefits.

关键词： Distributed robust optimization distributionally robust dispatch urban integrated energy system transmission system external column and constraint generation(C&CG) internal Bregman alternating direction method with multipliers(BADMM)

A self-powered solar-blind UV-enhanced Bi_(2)Se_(3)/a-Ga_(2)O_(3)/p-Si heterojunction photodetector for full spectral photoresponse and imaging

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Nano Research 2024年第4期17卷 2960-2970页

作者： Yajie Han Shujie Jiao Jiangcheng Jing Lei Chen Ping Rong Shuai Ren Dongbo Wang Shiyong Gao Jinzhong Wang school of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China

Self-powered full-spectrum photodetectors(PDs)offer numerous advantages,such as broad application fields,high precision,efficiency,and multi-functionality,which represent a highly promising and potentially valuable class of detectors for future ***,insensitive response to solar-blind ultraviolet(UV)and complex and expensive preparation processes greatly limit their performance and practical *** this study,a self-powered full-spectrum Bi_(2)Se_(3)/a-Ga_(2)O_(3)/p-Si heterojunction PD with high sensitivity for solar-blind UV band prepared by a simple and low-cost two-step synthesis method is *** results reveal that the developed PD has an excellent performance,such as high sensitivity from 200 to 850 nm,and a responsivity of 1.38 mA/W as well as a detectivity of 3.22×10^(10) Jones under 254 nm light at zero ***,the unencapsulated device displays exceptional stability and imaging *** is expected that Bi_(2)Se_(3)/a-Ga_(2)O_(3)/p-Si heterojunction PD with a simple and low-cost synthesis method has great potential for self-powered full-spectrum photodetectors.

关键词： Bi_(2)Se_(3)/a-Ga_(2)O_(3)/p-Si self-powered photodetector full spectral photoresponse imaging

Atomic interface regulation of rare-marth metal single atom catalysts for energy conversion

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Nano Research 2024年第5期17卷 3493-3515页

作者： Ziheng Zhan Zhiyi Sun Zihao Wei Yaqiong Li Wenxing Chen Shenghua Li Siping Pang school of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China

Efficient photocatalysis and electrocatalysis in energy conversion have been important strategies to alleviate energy crises and environmental *** recent years,with the rapid development of emerging catalysts,significant progress has been made in photocatalysis for converting solar energy into chemical energy and electrocatalysis for converting electrical energy into chemical ***,their selectivity and efficiency of the products are *** earth(RE)can achieve atomic level fine regulation of catalysts and play an crucial role in optimizing catalyst performance by their unique electronic and orbital ***,there is a lack of systematic review on the atomic interface regulation mechanism of RE and their role in energy conversion *** atom catalysts(SACs)provide clear active sites and 100%atomic utilization,which is conducive to exploring the regulatory mechanisms of ***,this review mainly takes atomic level doped RE as an example to review and discuss the atomic interface regulation role of RE elements in energy ***,a brief introduction was given to the synthesis strategies that can effectively exert the atomic interface regulation effect of RE,with a focus on the atomic interface regulation mechanism of ***,the regulatory mechanisms of RE atoms have been systematically summarized in various energy conversion ***,the challenges faced by RE in energy conversion,as well as future research directions and prospects,were pointed out.

关键词： rare earth elements interface regulation effect single-atom catalyst energy conversion

Multi-Objective Optimization of the Ultrasonic Scalpel Rod and Tip with Improved Performance:Vibration Frequency,Amplitude,and Service Life

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Chinese Journal of Mechanical Engineering 2024年第4期37卷 107-119页

作者： Jiaqi Zhao Yuhao Zhai Xuzhe Jia Naiwen Deng Kunxu Li Guangchao Han Rong Chen Dong Wang Wei Bai school of Mechanical Engineering and Electronic Information China University of GeosciencesWuhan 430074China Shenzhen Research institute China University of GeosciencesShenzhen 518057China College of Engineering Mathematics and Physical SciencesUniversity of ExeterExeter EX44QFUK Shenzhen Huazhong University of Science and Technology Research institute Shenzhen 518000China

Ultrasonic scalpel design for minimally invasive surgical procedures is mainly focused on optimizing cutting ***,an important issue is the low fatigue life of traditional ultrasonic scalpels,which affects their long-term reliability and effectiveness and creates hidden dangers for *** this study,a multi-objective optimal design for the cutting performance and fatigue life of ultrasonic scalpels was proposed using finite element analysis and fatigue *** optimal design parameters of resonance frequency and amplitude were *** setting the transition fillet and keeping the gain structure away from the node position to enable the scalpel to have a high service life with excellent cutting *** frequency modulation method of setting the vibration node bosses at the node position and setting the vibration antinode grooves at the antinode position was ***,the mechanism of the influence of various design elements,such as tip,shank,node position,and antinode position,on the resonance frequency,amplitude,and fatigue life of the ultrasonic scalpel was analyzed,and the optimal design principles of the ultrasonic scalpel were *** proposed ultrasonic scalpel design was confirmed by simulations,impedance measurements,and liver tissue cutting experiments,demonstrating its feasibility and enhanced *** research introduces innovative design strategies to improve the fatigue life and performance of ultrasonic scalpels to address an important issue in minimally invasive surgery.

关键词： Multi-objective optimal design Minimally invasive surgical procedures Service life Ultrasonic scalpel

Preparation of Flower-like Copper Foam Supported Co_(3)O_(4) Electrocatalyst and Its Hydrogen Evolution Performance

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Journal of Wuhan University of Technology(Materials Science) 2024年第2期39卷 327-331页

作者：李兆 CHENG Julong WANG Yanan WU Kunyao CAO Jing school of Materials Engineering Xi’an Aeronautical InstituteXian 710077China

Flower-like copper foam Co_(3)O_(4) catalysts(Co_(3)O_(4)/CF) were prepared by hydrothermal *** crystalline structure and microscopic morphology of the prepared samples were characterized by using X-ray diffractometer(XRD) and scanning electron microscope(SEM),and the electrochemical properties were investigated by an electrochemical *** experimental results show that the Co_(3)O_(4) catalysts are successfully prepared on the foamed copper support by hydrothermal method,and the material’s morphology is mainly flower *** the current density is 10 mA·cm^(-2),the overpotential value of the Co_(3)O_(4)/CF catalyst is 141 mV,lower than that of blank *** electrochemical impedance(EIS) spectrum shows that the R_(ct )value of the Co_(3)O_(4)/CF catalyst decreases,and the Coulomb curves of double-layer show that the electrochemically active area of the Co_(3)O_(4)/CF catalyst efficiently increases compared with that of the blank ***,the as-obtained Co_(3)O_(4)/CF catalyst exhibits a good hydrogen evolution rate,showing great applicability potential in the catalytic electrolysis of water for hydrogen production.

关键词： Co_(3)O_(4)/CF composite structure electrocatalysis hydrogen evolution reaction