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Investigations of the mechanical response of dummy HTPB propellant grain under ultrahigh acceleration overload conditions using onboard flight-test measurements

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Defence Technology（防务技术） 2024年第2期32卷 473-484页

作者： yiming Zhang Ningfei Wang Weihua ma Ran Wang Long Bai yi Wu School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Beijing System Design Institute of Electro-mechanic Engineering Beijing 100854China Xi'an Changfeng Research Institute of Mechanism and Electricity Xi'an 710065China

In this paper,to study the mechanical responses of a solid propellant subjected to ultrahigh acceleration overload during the gun-launch process,specifically designed projectile flight tests with an onboard measurement system were *** projectiles containing dummy HTPB propellant grains were successfully recovered after the flight tests with an ultrahigh acceleration overload value of 8100 *** onboard-measured time-resolved axial displacement,contact stress and overload values were successfully obtained and *** compression tests of the dummy HTPB propellant used in the gunlaunched tests were carried out at low and intermediate strain rates to characterize the propellant's dynamic properties.A linear viscoelastic constitutive model was employed and applied in finite-element simulations of the projectile-launching *** the launch process,the dummy propellant grain exhibited large deformation due to the high acceleration overload,possibly leading to friction between the motor case and propellant *** calculated contact stress showed good agreement with the experimental results,though discrepancies in the overall displacement of the dummy propellant grain were *** dynamic mechanical response process of the dummy propellant grain was analysed in *** results can be used to estimate the structural integrity of the analysed dummy propellant grain during the gun-launch process.

关键词： Gun-launched flight test Dummy HTPB propellant Onboard measurements Utrahigh overload Mechanical response

Size-controlled synthesis and near-infrared photothermal response of Cp^(*)Rh-based metalla[2]catenanes and rectangular metallamacrocycles

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Chinese Chemical Letters 2024年第6期35卷 337-343页

作者： ying Zhao yin-Hang Chai Tian Chen Jie Zheng ting-ting Li Francisco Aznarez Li-Long Dang Lu-Fang ma College of Chemistry and Chemical Engineering Henan Key Laboratory of Function-Oriented Porous MaterialsLuoyang Normal UniversityLuoyang 471934China College of Chemistry Zhengzhou UniversityZhengzhou 450001China Shanghai Key Laboratory of Molecular Catalysis and Innovative materials State Key Laboratory of Molecular Engineering of PolymersDepartment of ChemistryFudan UniversityShanghai 200438China

A variety of research reports on novel supramolecular topologies have been published over the last ***,it is still a great challenge to tap into the inner functional properties of these ***,two tetranuclear metallamacrocycles 1 and 2 and four octonuclear[2]catenanes 3-6 were constructed successfully via a coordination-driven self-assembly strategy,by conscious design and use of the tetramethyl bidentate pyridine ligand L1,and the appropriate selection of six binuclear half-sandwich rhodium building units with different longitudinal *** complexes have been fully characterized by single crystal X-ray diffraction analysis and NMR ***,near-infrared photothermal studies of the obtained[2]catenanes reveal different photothermal response in solid and solution states,which may be attributed to a strong fluorescence quenching effect of the half-sandwich organometallic fragment and different conjugated effect of Cp^(*)Rh based building blocks in the interlocking *** photothermal conversion efficiencies of[2]catenanes 4-6 fall in the range 30.5%-16.5% *** contribution aims to play a key role in the experimental development of Cp^(*)-based photothermal materials.

关键词： Catenanes Photothermal materials Supramolecular topologies Half-sandwich fragment 3,3'-N-donor analogues

Simulation of nuclear isomer production in laser-induced plasma

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matter and Radiation at Extremes 2024年第5期9卷 1-9页

作者： Zhiguo ma Yumiao Wang yi Yang Youjing Wang Kai Zhao yixin Li Changbo Fu Wanbing He Yugang ma Key Laboratory of Nuclear Physics and Ion-Beam Application(MoE) Institute of Modern PhysicsFudan UniversityShanghai 200433China

Nuclear isomers play essential roles in various fields,including stellar nucleosynthesis,nuclear clocks,nuclear batteries,clean nuclear energy,and-ray *** technological advances in high-intensity lasers have made it possible to excite or de-excite nuclear isomers using table-top laser *** a particle-in-cell code,we investigate the interaction of a laser with a nanowire array and calculate the production rates of the^(73m)Ge(E_(1)=13.3 keV)and^(107m)Ag(E_(1)=93.1 keV)***^(73m1)Ge,production by Coulomb excitation is found to contribute a peak efficiency of 1.0×10^(19) particles s^(−1)J^(−1),while nuclear excitation by electron capture(NEEC)contributes a peak of 1.65×10^(11)particles s^(−1)J^(−1).These results indicate a high isomeric production ratio,as well as demonstrating the potential for confirming the existence of NEEC,a long-expected but so far experimentally unobserved fundamental process.

关键词： process. isomers excitation

Double random number encryption blind watermarking technique based on DWT-DCT domain

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Optoelectronics Letters 2024年第10期20卷 614-622页

作者： WANG Chenglong ma yi WANG Xia National Engineering Research Center for Technology and Equipment of Environmental Deposition Lanzhou Jiaotong University Key Laboratory of Opto-Technology and Intelligent Control Ministry of Education Lanzhou Jiaotong University

Blind watermarking plays a significant role in copyright protection and information hiding. To enhance the security of watermark image information, a dual encryption method is proposed, which combines block shuffling with Logistic chaos encryption using two sets of random numbers as keys. This dual encryption technique is applied to blind watermark images, utilizing a combination of discrete wavelet transform(DWT) and discrete cosine transform(DCT) as the embedding method. First, the watermark image is divided into small blocks, which are shuffled and rearranged using one set of random numbers as the key, while recording the shuffling sequence of block positions. Subsequently, the shuffled blocks are reassembled into an image, and another set of random numbers is used as the key for Logistic chaos encryption, rendering the watermark image chaotically invisible. Then, a double DWT is applied to the carrier image, followed by a DCT, allowing the encrypted watermark image to be embedded. This achieves the concealment of the blind watermark. Experimental results demonstrate that this method exhibits robustness, excellent invisibility, and secrecy.

关键词： A

Tuning interface mechanism of FeCo alloy embedded N,S-codoped carbon substrate for rechargeable Zn-air battery

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Journal of Energy Chemistry 2024年第6期93卷 400-410,I0010页

作者： Hui Chang Lulu Zhao Shan Zhao Zong-Lin Liu Peng-Fei Wang ying Xie ting-Feng yi School of materials Science and Engineering Northeastern UniversityShenyang 110819LiaoningChina Key Laboratory of Functional Inorganic material Chemistry Ministry of EducationSchool of Chemistry and Materials ScienceHeilongjiang UniversityHarbin 150080HeilongjiangChina Key Laboratory of Dielectric and Electrolyte Functional material Hebei Province School of Resources and MaterialsNortheastern University at QinhuangdaoQinhuangdao 066004HebeiChina

The interface mechanism between catalyst and carbon substrate has been the focus of *** this paper,the FeCo alloy embedded N,S co-doped carbon substrate bifunctional catalyst(FeCo/S-NC)is obtained by a simple one-step pyrolysis *** experimental results and density functional theory(DFT)calculation show that the formation of FeCo alloy is conducive to promoting electron transfer,and the introduction of S atom can enhance the interaction between FeCo alloy and carbon substrate,thus inhibiting the migration and agglomeration of particles on the surface of carbon *** FeCo/SNC catalysts show outstanding performance for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).FeCo/S-NC shows a high half-wave potential(E_(1/2)=0.8823 V)for ORR and a low overpotential at 10 ma cm^(-2)(E_(j=10)=299 mV)for *** addition,compared with Pt/C+RuO_(2) assembled Zn-air battery(ZAB),the FeCo/S-NC assembled ZAB exhibits a larger power density(198.8 mW cm^(-2)),a higher specific capacity(786.1 ma h g_(zn)~(-1)),and ultra-stable cycle *** results confirm that the optimized composition and the interfacial interaction between catalyst and carbon substrate synergistically enhance the electrochemical performance.

关键词： FeCo alloy N S co-doped carbon DFT calculation Zn-air batteries Interfacial interaction

Extended wet sieving method for determination of complete particle size distribution of general soils

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 242-257页

作者： Shengnan ma yi Song Jiawei Liu Xingyu Kang Zhongqi Quentin Yue Department of Civil Engineering The University of Hong KongHong KongChina

The traditional standard wet sieving method uses steel sieves with aperture?0.063 mm and can only determine the particle size distribution(PSD)of gravel and sand in general *** paper extends the traditional method and presents an extended wet sieving *** extended method uses both the steel sieves and the nylon filter cloth *** apertures of the cloth sieves are smaller than 0.063 mm and equal 0.048 mm,0.038 mm,0.014 mm,0.012 mm,0.0063 mm,0.004 mm,0.003 mm,0.002 mm,and 0.001 mm,*** extended method uses five steps to separate the general soil into many material sub-groups of gravel,sand,silt and clay with known particle size *** complete PSD of the general soil is then calculated from the dry masses of the individual material *** extended method is demonstrated with a general soil of completely decomposed granite(CDG)in Hong Kong,*** silt and clay materials with different particle size ranges are further examined,checked and verified using stereomicroscopic observation,physical and chemical property *** results further confirm the correctness of the extended wet sieving method.

关键词： Particle size distribution(PSD) General soil Silt Clay Wet sieving Physical and chemical properties

Feasibility study of the photonuclear reaction cross section of medical radioisotopes using a laser Compton scattering gamma source

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Nuclear Science and Techniques 2024年第9期35卷 168-177页

作者： Yu-Ning Gu Wei-Juan Zhao Xi-Guang Cao Yu-Xuan Yang ting-Kai ma Zheng-Li Liao Fei-Long Xu Yu-Gang ma School of Physics and Microeletronics Zhengzhou UniversityZhengzhou 450001China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201210China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China School of Nuclear Science and Technology University of South ChinaHengyang 421001China Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China Shanghai Research Center for Theoretical Nuclear Physics NSFC and Fudan UniversityShanghai 200438China

In recent years,the gap between the supply and demand of medical radioisotopes has increased,necessitating new methods for producing medical *** reactions based on gamma sources have unique advantages in terms of producing high specific activity and innovative medical ***,the lack of experimental data on reaction cross sections for photonuclear reactions of medical radioisotopes of interest has severely limited the development and production of photonuclear transmutation medical *** this study,the entire process of the generation,decay,and measurement of medical radioisotopes was simulated using online gamma activation and offline gamma measurements combined with a shielding gamma-ray *** on a quasi-monochromatic gamma beam from the Shanghai Laser Electron Gamma Source(SLEGS),the feasibility of this measurement of production cross section for surveyed medi-cal radioisotopes was simulated,and specific solutions for measuring medical radioisotopes with ultra-low production cross sections were *** feasibility of this method for high-precision measurements of the reaction cross section of medical radioisotopes was demonstrated.

关键词： Medical radioisotope Photonuclear reaction GEANT4 Shanghai Laser Electron Gamma Source(SLEGS) Low-background gamma-ray spectrometer

Orientation and Decision-making for Soccer Based on Sports Analytics and AI:A Systematic Review

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IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 37-57页

作者： Zhiqiang Pu yi Pan Shijie Wang Boyin Liu Min Chen Hao ma yixiong Cui the School of Artificial Intelligence University of Chinese Academy of Sciences the Institute of Automation Chinese Academy of Sciences the Nanjing Artificial Intelligence Research of IA the School of Sports Engineering Beijing Sport University

Due to ever-growing soccer data collection approaches and progressing artificial intelligence(AI) methods, soccer analysis, evaluation, and decision-making have received increasing interest from not only the professional sports analytics realm but also the academic AI research community. AI brings gamechanging approaches for soccer analytics where soccer has been a typical benchmark for AI research. The combination has been an emerging topic. In this paper, soccer match analytics are taken as a complete observation-orientation-decision-action(OODA) *** addition, as in AI frameworks such as that for reinforcement learning, interacting with a virtual environment enables an evolving model. Therefore, both soccer analytics in the real world and virtual domains are discussed. With the intersection of the OODA loop and the real-virtual domains, available soccer data, including event and tracking data, and diverse orientation and decisionmaking models for both real-world and virtual soccer matches are comprehensively reviewed. Finally, some promising directions in this interdisciplinary area are pointed out. It is claimed that paradigms for both professional sports analytics and AI research could be combined. Moreover, it is quite promising to bridge the gap between the real and virtual domains for soccer match analysis and decision-making.

关键词： Artificial intelligence(AI) decision-making football review soccer sports analytics

Accuracy evaluation for in-situ machining reference points binocular measurement based on credibility probability

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Chinese Journal of Aeronautics 2024年第1期37卷 472-486页

作者： Binchao YU Wei LIU Yanze ZHANG Dazhi ma Zhenyuan JIA yi YUE Jiabo ZHANG Key Laboratory for Precision and Non-Traditional machining Technology of the Ministry of Education Dalian University of TechnologyDalian 116024China Beijing Spacecrafts China Academy of Space TechnologyBeijing 100081China

Passive binocular measurement systems are being increasingly utilized in the in-situ industries of automobiles,aviation,and aerospace,*** to their excellent qualities of accuracy,efficiency,and cost *** the barrier of evaluating the accuracy of measured objects resulted from the unequal equivalent focal length and quantization of pixels,has limited their further development and application of high requirements for in-situ machining,e.g.,the measurement of machining reference points for the positioning of robotic drilling in aerospace *** this paper,an accuracy evaluation method is proposed to address the ***,the unequal equivalent focal length is considered to improve the accuracy of 3D ***,the credibility probability model is developed to calculate the probability of the observed error in the public view of the binocular measurement system and indicates the direction of ***,the in-situ experiment is carried out to validate the method within the effective public view range of 300 mm×300 *** experiment results show that the RMSs of observed errors are superior to 0.035 mm,and the credibility probabilities are all higher than 0.91;the maximum 3D reconstruction accuracy improvement is 60.3%,with the error reduced from 0.078 mm to 0.031 mm.

关键词： Aerospace manufacturing Binocular vision Credibility probability Pixel quantization Unequal equivalent focal length