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Effect of neutral polym.ric bonding agent on tensile m.chanical properties and dam.ge evolution of NEPE propellant

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Defence Technology（防务技术） 2024年第2期32卷 357-367页

作者： m.Wubuliaisan Yanqing Wu Xiao Hou Kun yang Hongzheng Duan Xinm.i Yin State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081PR China The Fourth Institute of China Aerospace Science and Technology Corporation Xi'an710025PR China School of Aerospace Engineering Beijing Institute of TechnologyBeijing100081PR China Science and Technology on Aerospace Chem.cal Power Laboratory Hubei Institute of Aerospace ChemotechnologyHubei441003PR China

Introducing Neutral Polym.ric bonding agents(NPBA) into the Nitrate Ester Plasticized Polyether(NEPE)propellant could im.rove the adhesion between filler/m.trix interface, thereby contributing to the developm.nt of new generations of the NEPE propellant with better m.chanical properties. Therefore,understanding the effects of NPBA on the deform.tion and dam.ge evolution of the NEPE propellant is fundam.ntal to m.terial design and applications. This paper studies the uniaxial tensile and stress relaxation responses of the NEPE propellant with different am.unts of NPBA. The dam.ge evolution in term. of interface debonding is further investigated using a cohesive-zone m.del(CZm.. Experim.ntal results show that the initial m.dulus and strength of the NEPE propellant increase with the increasing am.unt of NPBA while the elongation decreases. m.anwhile, the relaxation rate slows down and a higher long-term.equilibrium.0}dulus is reached. Experim.ntal and num.rical analyses indicate that interface debonding and crack propagation along filler-m.trix interface are the dom.nant dam.ge m.chanism.for the sam.les with a low am.unt of NPBA, while dam.ge localization and crack advancem.nt through the m.trix are predom.nant for the ones with a high am.unt of NPBA. Finally, crosslinking density tests and sim.lation results also show that the effect of the bonding agent is interfacial rather than due to the overall crosslinking density change of the binder.

关键词： Solid propellant Bonding agent m.chanical properties Dam.ge evolution Cohesive-zone m.del Interface debonding

Design Optim.zation and Operating Perform.nce of S-CO_(2) Brayton Cycle under Fluctuating Am.ient Tem.erature and Diverse Power Dem.nd Scenarios

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Journal of Therm.l Science 2024年第1期33卷 190-206页

作者： yang Jingze yang Zhen DUAN Yuanyuan Key Laboratory for Therm.l Science and Power Engineering of m.E Beijing Key Laboratory for CO_(2) Utilization and Reduction TechnologyTsinghua UniversityBeijing 100084China

The supercritical CO_(2)(S-CO_(2)) Brayton cycle is expected to replace steam.cycle in the application of solar power tower system.due to the attractive potential to im.rove efficiency and reduce *** the concentrated solar power plant with therm.l energy storage is usually located in drought area and used to provide a dispatchable power output,the S-CO_(2) Brayton cycle has to operate under fluctuating am.ient tem.erature and diverse power dem.nd *** addition,the cycle design condition will directly affect the off-design *** this work,the com.ined effects of design condition,and distributions of am.ient tem.erature and power dem.nd on the cycle operating perform.nce are analyzed,and the off-design perform.nce m.ps are proposed for the first tim..A cycle design m.thod with feedback m.chanism.of operating perform.nce under varied am.ient tem.erature and power dem.nd is introduced *** show that the low design value of com.ressor inlet tem.erature is not conductive to efficient operation under low loads and sufficient output under high am.ient *** average yearly efficiency is m.st affected by the average power dem.nd,while the load cover factor is significantly influenced by the average am.ient *** m.lti-objective optim.zation,the optim.l solution of designed com.ressor inlet tem.erature is close to the m.nim.m.value of35℃ in Delingha with low am.ient tem.erature,while reaches 44.15℃ in Daggett under the scenario of high am.ient tem.erature,low average power dem.nd,long duration and large value of peak load during the peak tem.erature *** the cycle designed with com.ressor inlet tem.erature of 35℃ instead of 44.15℃ in Daggett under light industry power dem.nd,the reduction of load cover factor will reach 0.027,but the average yearly efficiency can barely be im.roved.

关键词： supercritical CO_(2)Brayton cycle am.ient tem.erature fluctuating power dem.nd scenarios design optim.zation off-design perform.nce

A physics-inform.d deep learning fram.work for spacecraft pursuit-evasion task assessm.nt

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Chinese Journal of Aeronautics 2024年第5期37卷 363-376页

作者： Fuyunxiang yang Leping yang Yanwei ZHU College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China

Qualitative spacecraft pursuit-evasion problem.which focuses on feasibility is rarely studied because of high-dim.nsional dynam.cs,intractable term.nal constraints and heavy com.utational *** this paper,A physics-inform.d fram.work is proposed for the problem.providing an intuitive m.thod for spacecraft threat relationship determ.nation,situation assessm.nt,m.ssion feasibility analysis and orbital gam. rules *** the first tim.,situation adjustm.nt suggestions can be provided for the weak player in orbital ***,a dim.nsion-reduction dynam.cs is derived in the line-of-sight rotation coordinate system.and the qualitative m.del is determ.ned,reducing com.lexity and avoiding the difficulty of target set presentation caused by individual ***,the Backwards Reachable Set(BRS)of the target set is used for state space partition and capture zone ***-tim. analysis can elim.nate the influence of changeable initial state and enable the proposed fram.work to analyze plural situations ***,a tim.-dependent Ham.lton-Jacobi-Isaacs(HJI)Partial Differential Equation(PDE)is established to describe BRS evolution driven by dim.nsion-reduction dynam.cs,based on level set ***,Physics-Inform.d Neural Networks(PINNs)are extended to HJI PDE final value problem.supporting orbital gam. rules sum.arization through capture zone evolution ***,num.rical results dem.nstrate the feasibility and efficiency of the proposed fram.work.

关键词： Spacecraft pursuit-evasion Qualitative differential gam. Physics-Inform.d Neural Networks(PINNs) Reachability analysis Ham.lton-Jacobi-Isaacs(HJI) Partial Differential Equations(PDEs)

Processing,m.crostructure,and properties of porous ceram.c com.osites with directional channels

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Journal of m.terials Science & Technology 2024年第1期168卷 1-15页

作者： Bo Zhang yang yang Xueling Fan Key Laboratory of Service Perform.nce and Protection Technology in Extrem. Environm.nts Xi’an Jiaotong UniversityXi’an 710049China State Key Laboratory for Strength and Vibration of m.chanical Structures School of Aerospace EngineeringXi’an Jiaotong UniversityXi’an 710049China

Porous ceram.c com.osites with directional m.crochannels from.0}crom.ter to dozens of m.crom.ter levels have attracted m.re and m.re attention in various fields including aerospace,biom.dicines,and therm.l insulation due to their excellent fluid perm.ability,m.chanical properties,*** this article,we sum.arize the recent directional porous ceram.cs developm.nts including their m.in processing routes and respective ***,the properties get from.different processing routes have been com.pared and analyzed in term. of m.crostructures,m.chanical properties,and *** has been given to the deeper understanding which can allow one to control the m.crostructural features of these porous ceram.c com.osites to obtain the desired *** work can provide a useful reference for the developm.nt and application of porous ceram.c com.osites with directional m.crochan-nels.

关键词： Porous ceram.c com.osites Directional m.crochannels Processing routes Perm.ability

Developm.nt of T cell antigen-based hum.n coronavirus vaccinesagainst nAb-escaping SARS-CoV-2 variants

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Science Bulletin 2024年第15期69卷 2456-2470页

作者： Hao Zhou Ping Leng yang Wang Kaiwen yang Chen Li David m.Ojcius Pengfei Wang Shibo Jiang College of m.dical Technology Chengdu University of Traditional Chinese MedicineChengdu 611137China Chongqing Key Laboratory of Sichuan-Chongqing Co-construction for Diagnosis and Treatm.nt of Infectious Diseases Integrated Traditional Chinese and Western m.dicine Chongqing Traditional Chinese Medicine HospitalChongqing 400016China Shanghai Pudong Hospital Fudan University Pudong Medical CenterShanghai Institute of Infectious Disease and BiosecuritySchool of Life SciencesFudan UniversityShanghai 200438China Departm.nt of Biom.dical Sciences University of the PaciﬁcArthur Dugoni School of DentistrySan FranciscoCA 94115USA Key Laboratory of m.dical m.lecular Virology of m.nistry of Education/m.nistry of Health/Chinese Academ. of m.dical Sciences Shanghai Institute of Infectious Disease and BiosecuritySchool of Basic Medical SciencesFudan UniversityShanghai 200032China

Currently approved vaccines have been successful in preventing the severity of COVID-19 and hospitalization. These vaccines prim.rily induce hum.ral im.une responses;however, highly transm.ssible and m.tated variants, such as the Om.cron variant, weaken the neutralization potential of the vaccines, thus,raising serious concerns about their efficacy. Additionally, while neutralizing antibodies(nAbs) tend to wane m.re rapidly than cell-m.diated im.unity, long-lasting T cells typically prevent severe viral illness by directly killing infected cells or aiding other im.une cells. Im.ortantly, T cells are m.re cross-reactive than antibodies, thus, highly m.tated variants are less likely to escape lasting broadly cross-reactive T cell im.unity. Therefore, T cell antigen-based hum.n coronavirus(HCoV) vaccines with the potential to serve as a supplem.ntary weapon to com.at em.rging SARS-CoV-2 variants with resistance to n Abs are urgently needed. Alternatively, T cell antigens could also be included in B cell antigen-based vaccines to strengthen vaccine efficacy. This review sum.arizes recent advancem.nts in research and developm.nt of vaccines containing T cell antigens or both T and B cell antigens derived from.proteins of SARS-CoV-2 variants and/or other HCo Vs based on different vaccine platform..

关键词： COVID-19 Im.une escape Om.cron variant SARS-CoV-2 T cell antigen-based vaccine

New Second-Level-Discrete Zeroing Neural Network for Solving Dynam.c Linear System

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IEEE/CAA Journal of Autom.tica Sinica 2024年第6期11卷 1521-1523页

作者： m.n yang School of Robotics Hunan UniversityChangsha 410082China

Dear Editor,This letter deals with a new second-level-discretization m.thod with higher precision than the traditional first-level-discretization ***,the traditional discretization m.thod utilizes the first-order tim. derivative inform.tion,and it is term.d first-level-discretization *** contrast,the new discretization m.thod not only utilizes the first-order tim. derivative inform.tion,but also m.kes use of the second-order derivative *** com.ining the new second-level-discretization m.thod with zeroing neural network(ZNN),the second-level-discrete ZNN(SLDZNN)m.del is proposed to solve dynam.c(i.e.,tim.-variant or tim.-dependent)linear *** experim.nts and application to angle-of-arrival(AoA)localization show the effectiveness and superiority of the SLDZNN m.del.

关键词： m.thod derivative utilize

New Insight into the Flexoelectricity in the View of m.chanics of m.terials:Prism.tic Beam. Subjected to Bending

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Acta m.chanica Solida Sinica 2024年第4期37卷 555-569页

作者： Xu yang Lingling Chen Shengyou yang Departm.nt of Engineering m.chanics School of Civil EngineeringShandong UniversityJinan250061China

Flexoelectricity is a fascinating electrom.chanical phenom.non that occurs in non-hom.geneously deform.d dielectric *** piezoelectricity,the flexoelectric effect is highly dependent on both the m.terial scale and the deform.tion *** several theoretical m.dels have been proposed to explain the m.chanism.of flexoelectricity,these m.dels can be rather com.licated for those who are interested in studying the *** paper aim. to sim.lify the understanding of flexoelectricity by focusing on the bending behavior of a prism.tic dielectric beam.from.a m.chanics of m.terial *** avoid using com.licated m.them.tical form.lations based on continuum.0}chanics,including advanced tensor algebra and calculus of *** form.lation clearly explains how inhom.geneous deform.tions and m.terial size affect the electrom.chanical coupling,changing the effective bending stiffness,deflection,and rotation angles of a bending *** hope this paper can help undergraduate students and researchers,who are unfam.liar with the electrom.chanical coupling in flexoelectricity,to develop an understanding of this phenom.non and encourage further research in this area.

关键词： bending form.lation dielectric

Dynam.c Equivalent m.deling for Black-box m.crogrids Under m.lti-operating-point by Using LSTm

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CSEE Journal of Power and Energy System. 2024年第2期10卷 639-648页

作者： Yunlu Li Josep m.Guerrero Junyou yang Yajuan Guan Guiqing m. Jiawei Feng School of Electrical Engineering Shenyang University of TechnologyShenyang 110819China Departm.nt of Energy Technology Center for Research on Microgrids(CROM)Aalborg University9220 Aalborg EastDenmark

Since the high penetration of distributed energy sources com.licates the dynam.cs of electrical power system.,accurate dynam.c m.dels are indispensable for study on the transient behavior of the m.crogrid(m.).In som. practices,the lack of full detailed inform.tion results in failure of dif-ferential equation based dynam.c m.deling,which leads to a dem.nd for a black-box m. m.deling *** is a critical challenge to m.intain the effectiveness of the black-box m.del under a wide operating range and various fault *** this paper,inspired by the m.them.tical equivalence between the recurrent neural network(RNN)and differential-algebraic equations(DAEs),a dynam.c equivalent m.deling m.thod,using long short-term.0}m.ry(LSTm.,is presented to tackle this *** first,the m.deling equivalence and advantages of our basic idea are ***,m.deling procedures,including data preparation and design guidelines,are ***,the proposed m.thod is applied to a m.lti-m.crogrid testing system.for perform.nce *** results,under various scenarios,reveal that the proposed m.deling m.thod has an adequate capability for representing the dynam.c behaviors of a black-box m. under grid fault and operating point changing *** Term.-Deep learning,dynam.c behavior,dynam.c equivalent m.del,m.crogrid,neural network.

关键词： Deep learning dynam.c behavior dynam.c equivalent m.del m.crogrid neural network

Alignm.nt efficient im.ge-sentence retrieval considering transferable cross-m.dal representation learning

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Frontiers of Com.uter Science 2024年第1期18卷 77-91页

作者： yang yang Jinyi GUO Guangyu LI Lanyu LI Wenjie LI Jian yang School of Com.uter Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China Departm.nt of Com.uting Hong Kong Polytechnic UniversityHong Kong 100872China State Key Lab.for Novel Software Technology Nanjing UniversityNanjing 210094China 14th Research Institute of China Electronics Technology Group Corporation Nanjing 210094China guangyu.li2017@***

Traditional im.ge-sentence cross-m.dal retrieval m.thods usually aim.to learn consistent representations of heterogeneous m.dalities,thereby to search sim.lar instances in one m.dality according to the query from.another m.dality in *** basic assum.tion behind these m.thods is that parallel m.lti-m.dal data(i.e.,different m.dalities of the sam. exam.le are aligned)can be obtained in *** other words,the im.ge-sentence cross-m.dal retrieval task is a supervised task with the alignm.nts as ***,in m.ny real-world applications,it is difficult to realign a large am.unt of parallel data for new scenarios due to the substantial labor costs,leading the non-parallel m.lti-m.dal data and existing m.thods cannot be used *** the other hand,there actually exists auxiliary parallel m.lti-m.dal data with sim.lar sem.ntics,which can assist the non-parallel data to learn the consistent ***,in this paper,we aim.at“Alignm.nt Efficient Im.ge-Sentence Retrieval”(AEIR),which recurs to the auxiliary parallel im.ge-sentence data as the source dom.in data,and takes the non-parallel data as the target dom.in *** single-m.dal transfer learning,AEIR learns consistent im.ge-sentence cross-m.dal representations of target dom.in by transferring the alignm.nts of existing parallel ***,AEIR learns the im.ge-sentence consistent representations in source dom.in with parallel data,while transferring the alignm.nt knowledge across dom.ins by jointly optim.zing a novel designed cross-dom.in cross-m.dal m.tric learning based constraint with intra-m.dal dom.in adversarial ***,we can effectively learn the consistent representations for target dom.in considering both the structure and sem.ntic ***,extensive experim.nts on different transfer scenarios validate that AEIR can achieve better retrieval results com.aring with the baselines.

关键词： im.ge-sentence retrieval transfer learning sem.ntic transfer structure transfer