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An internal ballistic model of electromagnetic railgun based on PFN coupled with multi-physical field and experimental validation

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Defence Technology（防务技术） 2024年第2期32卷 254-261页

作者： Benfeng Gu Haiyuan Li Baoming Li National key laboratory of Transient physics Nanjing University of Science and TechnologyNanjing 210094China

To accelerate the practicality of electromagnetic railguns,it is necessary to use a combination of threedimensional numerical simulation and experiments to study the mechanism of bore *** this paper,a three-dimensional numerical model of the augmented railgun with four parallel unconventional rails is introduced to simulate the internal ballistic process and realize the multi-physics field coupling calculation of the rail gun,and a test experiment of a medium-caliber electromagnetic launcher powered by pulse formation network(PFN)is carried *** test methods such as spectrometer,fiber grating and high-speed camera are used to test several parameters such as muzzle initial velocity,transient magnetic field strength and stress-strain of *** the simulation results and experimental data,the damage condition of the contact surface is analyzed.

关键词： Internal ballistic modeling Electromagnetic rail gun Multi-physics field coupling Experimental validation PFN

Thermodynamic nature of black holes in coexistence region

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Science China(physics,Mechanics & Astronomy) 2024年第5期67卷 27-32页

作者： Shao-Wen Wei Yu-Xiao Liu Lanzhou Center for Theoretical physics Key Laboratory of Theoretical Physics of Gansu Provinceand Key Laboratory of Quantum Theory and Applications of Mo ELanzhou UniversityLanzhou 730000China Institute of Theoretical physics&Research Center of Gravitation Lanzhou UniversityLanzhou 730000China

Studying the system state of coexistence regions will peek into to reveal microscopic interactions between different phases of a thermodynamic ***,there is no effective method to study thermodynamic nature of the coexistence black hole regions for the failure of the equation of *** at these coexistence states,in this work,we develop a general approach by introducing two new ratio *** first one is the ratio of the horizon radii of the saturated coexistence small and large black holes,and the second one measures that of the small black hole molecule number to the total molecule *** demonstrate that the first parameter can serve as an order parameter to characterize the first-order phase *** study also shows that the black hole state in the coexistence region is uniquely determined by these two introduced parameters bounded between 0 and *** results are quite significant in the analytical study of phase transition and the microscopic nature of black hole in the coexistence regions.

关键词： transition. state. thermodynamic

Advancing mid-infrared microdisk laser emission with Tm:YAG

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Science China(physics,Mechanics & Astronomy) 2024年第7期67卷 91-96页

作者： Zhaocong Wang Huiqi Li Lei Wang Yang Tan Feng Chen School of physics State Key Laboratory of Crystal MaterialsShandong UniversityJinan 250100China

Mid-infrared microcavity lasers have important applications in biosensing,mid-infrared spectroscopy,and environmental ***,the low output power of existing mid-infrared microcavity lasers hinders their practical *** drawback is attributed to the insufficient laser gain medium,which limits the development of mid-infrared whispering-gallerymode(WGM)*** address this issue,we have employed ion implantation-enhanced etching to fabricate Tm:YAG thin films as effective gain media for mid-infrared WGM *** Tm:YAG thin film,with a thickness of 2μm,exhibits excellent fluorescence ***,the Tm:YAG thin film is processed using focused ion beam to form microdisks with a diameter of 30μ*** 785 nm laser pumping,the maximum output power of the Tm:YAG microdisk at 2023.1 nm is229μW,with a slope efficiency of 2.9%.This work demonstrates the outstanding potential of Tm:YAG as a mid-infrared laser gain medium,providing a new option for the development of mid-infrared lasers.

关键词： microdisk microlaser ultrathin film

Understanding the Interfacial Energy Structure and Electron Extraction Process in Inverted Organic Solar Cells with Phosphine-Doped Cathode Interlayers

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Chinese Journal of chemistry 2024年第12期42卷 1347-1354页

作者： Yi Yang Jingwen Wang Yang Xiao Bowei Xu Jianhui Hou State key laboratory of Polymer physics and chemistry Beijing National Laboratory for Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China State key laboratory of Chemical Resource Engineering College of Materials Science and EngineeringBeijing University of Chemical TechnologyBejing 100029China University of Chinese Academy of Sciences Beijing 100049China

Comprehensive Summary Cathode interlayers(CILs)play an essential role in achieving efficient organic solar cells(OSCs).However,the electronic structure at the electrode/CIL/active layer interfaces and the underlying mechanisms for electron collection remain unclear,which becomes a major obstacle to develop high-performance ***,we investigate the relationship of the electron collection abilities of four cross-linked and n-doped CILs(c-NDI:P0,c-NDI:P1,c-NDI:P2,c-NDI:P3)with their electronic structure of space charge region at heterojunction *** accurately calculating the depletion region width according to the barrier height,doping density and permittivity,we put forward that the optimal thickness of CIL should be consistent with the depletion region width to realize the minimum energy *** a result,the depletion region width is largely reduced from 13 nm to 0.8 nm at the indium tin oxide(ITO)/c-NDI:P0 interface,resulting in a decent PCE of 17.7%for the corresponding inverted OSCs.

关键词： Organic solar cells Cathode interlayer Depletion region width Electric conductivity Electron transport Electron transfer Electron extraction process

Principal components of nuclear mass models

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Science China(physics,Mechanics & Astronomy) 2024年第7期67卷 65-71页

作者： Xin-Hui Wu Pengwei Zhao Department of physics Fuzhou UniversityFuzhou 350108China State key laboratory of Nuclear physics and Technology School of PhysicsPeking UniversityBeijing 100871China

Principal component analysis(PCA)is employed to extract the principal components(PCs)present in nuclear mass models for the first *** effects from different nuclear mass models are reintegrated and reorganized in the extracted *** PCs are recombined to build new mass models,which achieve better accuracy than the original theoretical mass *** comparison indicates that using the PCA approach,the effects contained in different mass models can be collaborated to improve nuclear mass predictions.

关键词： nuclear mass principal component analysis nuclear models statistical methods

Preliminary discussion on the ignition mechanism of exploding foil initiators igniting boron potassium nitrate

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Defence Technology（防务技术） 2024年第2期32卷 222-231页

作者： Haotian Jian Guoqiang Zheng Lejian Chen Zheng Ning Guofu Yin Peng Zhu Ruiqi Shen School of chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094China Micro-Nano Energetic Devices key laboratory of MIIT Nanjing University of Science and TechnologyNanjing 210094China Anhui Province key laboratory of Microsystem the 43rd Research Institute of CETCHefei 230088China Science and Technology on Applied Physical and chemistry laboratory Shanxi Applied Physics and Chemistry Research Institute Xi'an 710061China

Exploding foil initiator(EFI)is a kind of advanced device for initiating explosives,but its function is unstable when it comes to directly igniting *** solve the problem,this research aims to reveal the ignition mechanism of EFIs directly igniting *** oscilloscope,a photon Doppler velocimetry,and a plasma spectrum measurement system were employed to obtain information of electric characteristics,impact pressure,and plasma *** results of the electric characteristics and the impact pressure were inconsistent with ignition *** only thing that the ignition success tests had in common was that their plasma all had a relatively long period of high-temperature duration(HTD).It eventually concludes that the ignition mechanism in this research is the microconvection heat transfer rather than the shock initiation,which differs from that of exploding foil initiators detonating ***,the methods for evaluating the ignition success of semiconductor bridge initiators are not entirely applicable to the tests mentioned in this *** HTD is the critical parameter for judging the ignition success,and it is influenced by two factors:the late time discharge and the energy of the electric *** longer time of the late time discharge and the more energy of the electric explosion,the easier it is to expand the HTD,which improves the probability of the ignition success.

关键词： Exploding foil initiator PDV Plasma spectrum Ignition mechanism Boron potassium nitrate

Observation of accurately designed bound states in the continuum in momentum space

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Photonics Research 2024年第4期12卷 638-647页

作者： JIAJU WU JINGGUANG CHEN XIN QI ZHIWEI GUO JIAJUN WANG FENG WU YONG SUN YUNHUI LI HAITAO JIANG LEI SHI JIAN ZI HONG CHEN MOE key laboratory of Advanced Micro-Structured Materials School of Physics Science and EngineeringTongji UniversityShanghai 200092China State key laboratory of Surface physics Key Laboratory of Micro-and Nano-Photonic Structures(Ministry of Education)and Department of PhysicsFudan UniversityShanghai 200433China School of Optoelectronic Engineering Guangdong Polytechnic Normal UniversityGuangzhou 510665China

Bound states in the continuum(BICs)in artificial photonic structures have received considerable attention since they offer unique methods for the extreme field localization and enhancement of light-matter ***,the symmetry-protected BICs are located at high symmetric points,while the positions of accidental BICs achieved by tuning the parameters will appear at some points in momentum *** to now,to accurately design the position of the accidental BIC in momentum space is still a ***,we theoretically and experimentally demonstrate an accurately designed accidental BIC in a two-coupled-oscillator system consisting of bilayer gratings,where the optical response of each grating can be described by a single resonator *** changing the interlayer distance between the gratings to tune the propagation phase shift related to wave vectors,the position of the accidental BIC can be arbitrarily controlled in momentum ***,we present a general method and rigorous numerical analyses for extracting the polarization vector fields to observe the topological properties of BICs from the polarization-resolved transmission ***,an application of the highly efficient second harmonic generation assisted by quasi-BIC is *** work provides a straightforward strategy for manipulating BICs and studying their topological properties in momentum space.

关键词： polarization tuning resonator

Enhanced cycling stability and rate performance of Co-doped and La_(2)O_(3)-coated LiNi_(0.9)Mn_(0.1)O_(2) toward power battery

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Rare Metals 2024年第2期43卷 658-670页

作者： Jia-Qi Peng Yuan-Yuan Wei Dong-Ming Liu Yun Li Bin Hu Bin Huang Jian-Wen Yang Shun-Hua Xiao Ren-Heng Wang Guangxi key laboratory of Electrochemical and Magneto-Chemical Functional Materials College of Chemistry and BioengineeringGuilin University of TechnologyGuilin541004China key laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen518060China

Ultra-high nickel layered oxide cathode material with high energy density is the most promising material to improve the electrochemical performance of lithium-ion batteries(LIBs).However,the poor structural stability and severe surface/interface side reactions of the material lead to poor rate performance and cyclic stability,which limits its application in *** this paper,the dual-modification strategy of Co doping and La_(2)O_(3) coating is used to meet the above *** doping can effectively widen layer spacing and reduce Li^(+)/Ni^(2+) mixing,and La_(2)O_(3) coating can effectively eliminate the residual alkali on the surface of active material,inhibit the thickening of cathode electrolyte interphase(CEI)film and reduce surface/interface side ***,the modified material(NM90-CL)with excellent electrochemical properties is achieved through the synergistic enhancement of Co doping and La_(2)O_(3) *** capacity retention rate can reach 77.9%after 200 cycles at 1.0℃ and 75.7%after 200 cycles at 5.0℃.Its reversible capacity can up to 153.5 mAh·g^(–1) at 10.0℃.This dual-modification strategy will provide theoretical guidance and technical support for the synthesis of other high-performance electrode materials.

关键词： High nickel cathode material Co doping La_(2)O_(3) coating Electrochemical performance Electrochemical mechanism

Microscopic growth mechanism and edge states of monolayer 1T'-MoTe2

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Chinese physics B 2024年第4期33卷 474-480页

作者：赵海鹏刘隐杨胜国林陈昉陈明星 Kai Braun 罗心仪李思宇潘安练王笑 key laboratory for Micro-Nano physics and Technology of Hunan Province School of Physics and ElectronicsCollege of Materials Science and Engineering Hunan University key laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Synergetic Innovation Centre for Quantum Effects and Applications (SICQEA) Hunan Normal University State key laboratory of Powder Metallurgy Central South University Institute of Physical and Theoretical chemistry and LISA+ University of Tübingen

Transition metal ditellurides（TMTDs） have versatile physical properties,including non-trivial topology,Weyl semimetal states and unique spin *** growth of high-quality and large-scale monolayer TMTDs with preferred crystal phases is crucial for their ***,we demonstrate the epitaxial growth of 1T'-MoTe2on Au（111）and graphitized silicon carbide（Gr/SiC） by molecular beam epitaxy（MBE）.We investigate the morphology of the grown1T'-MoTe2at the atomic level by scanning tunnelling microscopy（STM） and reveal the corresponding microscopic growth *** is found that the unique ordered Te structures preferentially deposited on Au（111） regulate the growth of monolayer single crystal 1T'-MoTe2,while the Mo clusters were preferentially deposited on the Gr/SiC substrate,which impedes the ordered growth of monolayer *** confirm that the size of single crystal 1T'-MoTe2grown on Au（111）is nearly two orders of magnitude larger than that on Gr/*** scanning tunnelling spectroscopy（STS）,we observe that the STS spectrum of the monolayer 1T'-MoTe2nano-island at the edge is different from that at the interior,which exhibits enhanced conductivity.

关键词： 1T′-MoTe2 microscopic growth mechanism scanning tunneling microscopy/spectroscopy (STM/S) transition metal ditellurides