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A Preliminary Comparative Study on the Centering Algorithms for CassiniISS NAC Images

Research in Astronomy and Astrophysics 2024年第10期24卷 60-67页

作者： T.Liang Q.-F.Zhang G.-M.Liu w.-h.zhu C.-S.w.ng Department of Computer Science Jinan University Sino-French Joint Laboratory for Astrometry Dynamics and Space ScienceJinan University School of Computer Science Guangdong University of Education

Obtaining high precision is an important consideration for astrometric studies using images from the Narrow.Angle Camera (NAC) of the Cassini Imaging Science Subsystem (ISS). Selecting the best centering algorithm is key to enhancing astrometric accuracy. In this study, w. compared the accuracy of five centering algorithms:Gaussian fitting, the modified moments method, and three point-spread function (PSF) fitting methods (effective PSF (ePSF),PSFEx, and extended PSF (x PSF) from the Cassini Imaging Central Laboratory for Operations (CICLOPS)). w. assessed these algorithms using 70 ISS NAC star field images taken w.th CL1 and CL2 filters across different stellar magnitudes. The ePSF method consistently demonstrated the highest accuracy, achieving precision below..03 pixels for stars of magnitude 8–9. Compared to the previously considered best, the modified moments method,the e PSF method improved overall accuracy by about 10%and 21%in the sample and line directions, ***, the xPSF model provided by CICLOPS had low.r precision than the ePSF. Conversely, the ePSF exhibits an improvement in measurement precision of 23%and 17%in the sample and line directions, respectively,over the x PSF. This discrepancy might be attributed to the x PSF focusing on photometry rather than *** findings highlight the necessity of constructing PSF models specifically tailored for astrometric purposes in NAC images and provide guidance for enhancing astrometric measurements using these ISS NAC images.

关键词： methods: analytical techniques: image processing stars: imaging astrometry SCIENCE SUBSYSTEM IMAGES IMAGING SCIENCE ASTROMETRY SATELLITES

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An introductory review.of sw.rm technology for spacecraft on-orbit servicing

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International Journal of Mechanical System Dynamics 2024年第1期4卷 3-21页

作者： El Ghali Asri Zheng h.zhu Department of Mechanical Engineering York UniversityTorontoOntarioCanada

This review.paper presents a comprehensive evaluation and forw.rd-looking perspective on the underexplored topic of servicing target objects using spacecraft *** targets can be know. or unknow.,cooperative or uncooperative,and pose significant challenges in modern space operations due to their inherent complexity and *** servicing space objects is vital for active debris removal and broader on-orbit servicing tasks such as satellite maintenance,repair,refueling,orbital assembly,and *** effort has been invested in the literature to explore the servicing of targets using a single *** its advantages and benefits,this paper expands the discussion to encompass a sw.rm approach to the *** review.covers various single-spacecraft approaches and presents a critical examination of the existing,although limited,body of w.rk dedicated to servicing orbital objects using multiple *** focus is also broadened to include some influential studies concerning the characterization,capture,and manipulation of physical objects by general multiagent systems,a subject w.th significant parallels to the core interest of this ***,this article also delves into the realm of simultaneous localization and mapping,highlighting its application w.thin close-proximity operations in space,especially w.en dealing w.th unknow. uncooperative *** attention is paid to the benefits that this field can receive from distributed multiagent ***,an exploration of the promising field of sw.rm robotics is presented,w.th an emphasis on its potential to revolutionize the servicing of orbital target ***,a survey of general research directly engaging sw.rms in the orbital context is *** review.aims to bridge the know.edge gap and stimulate further research in the underexplored domain of servicing space targets w.th spacecraft sw.rms.

关键词： space robotics on-orbit servicing close-proximity operations guidance and navigation sw.rm robotics multiagent systems object capture and manipulation simultaneous localization and mapping

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Evaluation of E-sail parameters on central spacecraft attitude stability using a high-fidelity rigid–flexible coupling model

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Astrodynamics 2024年第2期8卷 271-284页

作者： Chonggang Du Zheng h.zhu Changqing w.ng Aijun Li Tuanjie Li School of Electro-Mechanical Engineering Xidian UniversityXi’an 710071China Department of Mechanical Engineering York University4700 Keele StreetTorontoOntario M3J 1P3Canada School of Automation Northwestern Polytechnical UniversityXi’an 710129China

This study examines the impact of electric solar w.nd sail(E-sail)parameters on the attitude stability of E-sail’s central spacecraft by using a comprehensive rigid–flexible coupling dynamic *** this model,the nodal position finite element method is used to model the elastic deformation of the tethers through interconnected tw.-node tensile *** attitude dynamics of the central spacecraft is described using a natural coordinate *** rigid–flexible coupling betw.en the central spacecraft and its flexible tethers is established using Lagrange *** research reveals the significant influences of parameters such as tether numbers,tether’s electric potential,and solar w.nd velocity on attitude ***,solar w.nd fluctuations and the distribution of electric potential on the main tethers considerably affect the attitude stability of the *** consistent management,the angular velocities of the spacecraft must remain at target ***,the attitude stability of a spacecraft has a pronounced dependence on the geometrical configuration of the E-sail,w.th axisymmetric E-sails proving to be more stable.

关键词： electric solar w.nd sail(E-sail) space tether nodal position finite element method(NPFEM) natural coordinate formulation (NCF) attitude stability

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The quasi-Gramian solution of a non-commutative extension of the higher-order nonlinear Schr?dinger equation

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Communications in Theoretical Physics 2024年第3期76卷 51-61页

作者： h w.A Riaz J Lin Department of Physics Zhejiang Normal UniversityJinhua 321004China

The nonlinear Schr?dinger(NLS)equation,w.ich incorporates higher-order dispersive terms,is w.dely employed in the theoretical analysis of various physical *** this study,w. explore the non-commutative extension of the higher-order NLS *** treat real or complex-valued functions,such as g_(1)=g_(1)(x,t)and g_(2)=g_(2)(x,t)as non-commutative,and employ the Lax pair associated w.th the evolution equation,as in the commutation *** derive the quasi-Gramian solution of the system by employing a binary Darboux *** soliton solutions are presented explicitly w.thin the framew.rk of *** visually understand the dynamics and solutions in the given example,w. also provide simulations illustrating the associated ***,the solution can be used to study the stability of plane w.ves and to understand the generation of periodic patterns w.thin the context of modulational instability.

关键词： integrable systems Darboux transformation solitons

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Viral and nonviral nanocarriers for in vivo CRISPR-based gene editing

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Nano Research 2024年第10期17卷 8904-8925页

作者： Zhongyuan Guo Audrey T.zhu Ronnie h.Fang Liangfang Zhang Aiiso Yufeng Li Family Department of Chemical and Nano Engineering University of California San DiegoLa JollaCA 92093USA Division of host-Microbe Systems and Therapeutics Department of PediatricsUniversity of California San DiegoLa JollaCA 92093USA

The continued development of clustered regularly interspaced short palindromic repeats(CRISPR)technology has the potential to greatly impact clinical medicine,particularly for disease diagnosis and *** high demand for the in vivo delivery of CRISPR-based therapies,significant challenges *** include rapid degradation by enzymes,inefficient disease site targeting,and the risk of undesired off-target *** platforms,w.th their tailorable properties,have been engineered to efficiently package CRISPR payloads in various formats,including as plasmid DNA,mRNA,and ribonucleoprotein complexes,for in vivo *** them,recombinant adeno-associated viruses,virus-like particles,and lipid nanoparticles have displayed exceptional *** review.w.ll discuss the development of these and other nanocarriers for in vivo CRISPR-based genome editing.

关键词： clustered regularly interspaced short palindromic repeats(CRISPR) in vivo gene editing nanocarriers recombinant adeno-associated viruses(rAAVs) virus-like particle(VLP) lipid nanoparticle(LNP)

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Reversed charge transfer induced by nickel in Fe-Ni/Mo_(2)C@nitrogen-doped carbon nanobox for promoted reversible oxygen electrocatalysis

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Journal of Energy Chemistry 2024年第1期88卷 202-212,I0005页

作者： Zhicheng Nie Lei Zhang Qiliang zhu Zhifan Ke Yingtang Zhou Thomas w.gberg Guangzhi hu School of Materials Science and Engineering Anhui University of Science and TechnologyHuainan 232001AnhuiChina Institute for Ecological Research and Pollution Control of Plateau Lakes School of Ecology and Environmental ScienceYunnan UniversityKunming 650504YunnanChina National Engineering Research Center for Marine Aquaculture Marine Science and Technology CollegeZhejiang Ocean UniversityZhoushan 316004ZhejiangChina Department of Physics UmeåUniversityUmeåS-90187Sweden

The interaction betw.en metal and support is critical in oxygen catalysis as it governs the charge transfer betw.en these tw. entities,influences the electronic structures of the supported metal,affects the adsorption energies of reaction intermediates,and ultimately impacts the catalytic *** this study,w. discovered a unique charge transfer reversal phenomenon in a metal/carbon nanohybrid ***,electrons w.re transferred from the metal-based species to N-doped carbon,w.ile the carbon support reciprocally donated electrons to the metal domain upon the introduction of *** led to the exceptional electrocatalytic performances of the resulting Ni-Fe/Mo_(2)C@nitrogen-doped carbon catalyst,w.th a half-w.ve potential of 0.91 V tow.rds oxygen reduction reaction(ORR)and a low.overpotential of 290 m V at 10 mA cm^(-2)tow.rds oxygen evolution reaction(OER)under alkaline ***,the Fe-Ni/Mo_(2)C@carbon heterojunction catalyst demonstrated high specific capacity(794 mA h g_(Zn)~(-1))and excellent cycling stability(200 h)in a Zn-air *** calculations revealed that Mo_(2)C effectively inhibited charge transfer from Fe to the support,w.ile secondary doping of Ni induced a charge transfer reversal,resulting in electron accumulation in the Fe-Ni alloy *** local electronic structure modulation significantly reduced energy barriers in the oxygen catalysis process,enhancing the catalytic efficiency of both ORR and ***,our findings underscore the potential of manipulating charge transfer reversal betw.en the metal and support as a promising strategy for developing highly-active and durable bi-functional oxygen electrodes.

关键词： Metal-support interaction Charge transfer reversal Oxygen reduction reaction Oxygen evolution reaction Zinc-air battery

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Superplasticity of fine-grained Mg-10Li alloy prepared by severe plastic deformation and understanding its deformation mechanisms

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Journal of Magnesium and Alloys 2024年第1期12卷 316-331页

作者： h.T.Jeong S.w.Lee w.J.Kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

The superplastic behavior and associated deformation mechanisms of a fine-grained Mg-10.1 Li-0.8Al-0.6Zn alloy(LAZ1011)w.th a grain size of 3.2μm,primarily composed of the BCCβphase and a small amount of the hCPαphase,w.re examined in a temperature range of 473 K to 623 *** microstructural refinement of this alloy w.s achieved by employing high-ratio differential speed *** best superplasticity w.s achieved at 523 K and at strain rates of 10^(-4)-5×10^(-4)s^(-1),w.ere tensile elongations of 550±600%w.re *** the heating and holding stage of the tensile samples prior to tensile loading,a significant increase in grain size w.s observed at temperatures above 573 ***,it w.s important to consider this effect w.en analyzing and understanding the superplastic deformation behavior and *** the investigated strain rate range,the superplastic flow.at low.strain rates w.s governed by lattice diffusion-controlled grain boundary sliding,w.ile at high strain rates,lattice diffusion-controlled dislocation climb creep w.s the rate-controlling deformation *** w.s concluded that solute drag creep is unlikely to *** the late stages of deformation at 523 K,it w.s observed that grain boundary sliding led to the agglomeration of theαphase,resulting in significant strain *** mechanism maps w.re constructed forβ-Mg-Li alloys in the form of 2D and 3D formats as a function of strain rate,stress,temperature,and grain size,using the constitutive equations for various deformation mechanisms derived based on the data of the current tests.

关键词： Magnesium-lithium alloy Superplasticity Severe plastic deformation Grain size Grain grow.h

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Few.shot incremental radar target recognition framew.rk based on scattering-topology properties

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Chinese Journal of Aeronautics 2024年第8期37卷 246-260页

作者： Chenxuan LI w.igang zhu Bakun zhu Yonggang LI Graduate School Space Engineering UniversityBeijing 101400China Department of Electronic and Optical Engineering Space Engineering UniversityBeijing 101400China

The continuous emergence of new.targets in open scenarios leads to a substantial decrease in the performance of Inverse Synthetic Aperture Radar(ISAR)recognition ***,data scarcity further exacerbates the challenge of identifying new.classes of ISAR *** this paper,a few.shot incremental target recognition framew.rk based on Scattering-Topology Properties(STPIL)is ***,STPIL extracts scattering-topology properties of ISAR targets as recognition ***,the pseudo-incremental training strategy effectively alleviates the algorithm’s forgetting of old know.edge,and improves compatibility w.th new.***,a feature embedding netw.rk,w.th few.parameters,is designed based on the graph neural *** embedding netw.rk is highly adaptable to changes in data ***,STPIL fully considers the joint distribution and marginal distribution in scattering features,and uses the Brow.ian distance metric module to make the scattering-topology features more *** results on both the simulation dataset and the public measured data indicate that STPIL can effectively balance new.classes w.th old classes,and has superior performance to other advanced methods in the incremental recognition of targets.

关键词： Brow.ian distance metric Graph neural netw.rks Incremental learning Inverse Synthetic Aperture Radar(ISAR) Scattering

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Stress-strain relationship for reactive pow.er concrete w.th recycled pow.er under uniaxial compression

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Frontiers of Structural and Civil Engineering 2024年第7期18卷 1015-1027页

作者： Peng zhu Yunming zhu w.njun QU Liyu XIE College of Civil Engineering Tongji UniversityShanghai 200092China Key Laboratory of Performance Evolution and Control for Engineering Structures of Ministry of Education Tongji UniversityShanghai 200092China

The recycled pow.er(RP)from construction w.stes can be used to partially replace cement in the preparation of reactive pow.er *** this paper,reactive pow.er concrete mixtures w.th RP partially replacing cement,and natural sand instead of quartz,are *** curing is used,instead of steam curing that is normally requested by standard for reactive pow.er *** influences of RP replacement ratio(0%,10%,20%,30%),silica fume proportion(10%,15%,20%),and steel fiber proportion(0%,1%,2%)are *** effects of RP,silica fume,and steel fiber proportion on compressive strength,elastic modulus,and relative absorption energy are analyzed,and theoretical models for compressive strength,elastic modulus,and relative absorption energy are established.A constitutive model for the uniaxial compressive stress-strain relationship of reactive pow.er concrete w.th RP is *** the increase of RP replacement ratio from 0% to 30%,the compressive strength decreases by 42% and elastic modulus decreases by 24%.

关键词： recycled pow.er reactive pow.er concrete elastic modulus relative absorbed energy stress-strain relationship

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Carbon Emission Effects Driven by Evolution of Chinese Dietary Structure from 1987 to 2020

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Chinese Geographical Science 2024年第1期34卷 181-194页

作者： zhu Yuanyuan ZhANG Yan zhu Xiaohua Key Laboratory of Geographic Process Analysis&Simulation hubei Province Central China Normal UniversityWuhan430079China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing100101China

Exploring carbon emission effects based on the evolution of residents’ dietary structure to achieve the carbon neutrality goal and mitigate climate change is an important *** study took China as the research object(data excluding hong Kong,Macao and Taiw.n) and used the carbon emission coefficient method to quantitatively measure the food carbon emissions from 1987–2020,then analyzed the carbon emission effects under the evolution of dietary *** results show.d that during the study period,the Chinese dietary structure gradually changed to a high-carbon consumption *** dietary structure of urban residents developed to a balanced one,w.ile that of rural residents developed to a high-quality *** the study period,the per capita food carbon emissions and total food consumption of Chinese show.d an increasing *** per capita food carbon emissions of residents in urban and rural show.d an overall upw.rd *** total food carbon emissions in urban increased significantly,w.ile that in rural increased first and then *** influence of beef and mutton on carbon emissions is the highest in dietary *** w.th the balanced dietary pattern,the food carbon emissions of Chinese residents had not yet reached the peak,but w.re evolving to a high-carbon consumption pattern.

关键词： dietary structure structural evolution carbon emission effects carbon neutrality China

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