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Influence of ion species on extraction characteristicsof mixed ion beams

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Chinese physics B 2024年第9期33卷 444-449页

作者： Ao Xu Pingping Gan Xiang Wan Yuanjie Shi institute of Electronic engineering China Academy of Engineering PhysicsMianyang 621999China

The spatial distributions of different kinds of ions are usually not completely the same in the process of *** order to study the reason for the different characteristics of ion extraction, a simplified simulation model of Cu+ andCr+ ions extraction process was established by 2D3V (two-dimensional in space and three- dimensional in velocity space)particle-in-cell (PIC) method. The effects of different extraction voltages from 0 V to 500 V on the density distribution ofCu+ and Cr+ ions and the change of plasma emission surface were analyzed. On the basis of this model, the ion densitydistribution characteristics of Cu+ ions mixed with Li+, Mg+, K+, Fe+, Y+, Ag+, Xe+, Au+, and Pb+ ions respectivelyunder 200-V extraction voltage are further simulated, and it is revealed that the atomic mass of the ions is the key reason fordifferent ion density distributions when different kinds of ions are mixed and extracted, which provides support for furtherunderstanding of ion extraction characteristics.

关键词： extraction ion species density distribution atomic mass

Mechanical responses and crystal plasticity model of CoCrNi medium-entropy alloy under ramp wave compression

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Matter and Radiation at Extremes 2024年第5期9卷 93-108页

作者： Jinlei Dong Xuping Zhang Guiji Wang Xianqian Wu Binqiang Luo Xuemiao Chen Fuli Tan Jianheng Zhao Chengwei Sun institute of Fluid physics China Academy of Engineering PhysicsMianyang 621999China institute of Mechanics Chinese Academy of SciencesBeijing 100190China institute of Applied Electronics China Academy of Engineering PhysicsMianyang 621999China

It is of substantial scientific significance and practical value to reveal and understand the multiscale mechanical properties and intrinsic mechanisms of medium-entropy alloys(MEAs)under high strain rates and *** this study,the mechanical responses and deformation mechanisms of an equiatomic CoCrNi MEA are investigated utilizing magnetically driven ramp wave compression(RWC)with a strain rate of 105 s^(−1).The CoCrNi MEA demonstrates excellent dynamic mechanical responses and yield strength under RWC compared with other advanced *** characterizations reveal that grain refinement and abundant micromechanisms,including dislocation slip,stacking faults,nanotwin network,and Lomer–Cottrell locks,collectively contribute to its excellent performance during ***,dense deformation twins and shear bands intersect,forming a weave-like microstructure that can disperse deformation and enhance *** the basis of these observations,we develop a modified crystal plasticity model with coupled dislocation and twinning mechanisms,providing a relatively accurate quantitative description of the multiscale behavior under *** results of simulations indicate that the activation of multilevel microstructures in CoCrNi MEA is primarily attributable to stress inhomogeneities and localized strain during *** research offers valuable insights into the dynamic mechanical responses of CoCrNi MEA,positioning it as a promising material for use under extreme dynamic conditions.

关键词： deformation alloy microstructure

Research on the influences of motion characteristics of jetting projectile charge under water

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Defence Technology（防务技术） 2024年第3期33卷 411-425页

作者： Xing Chen Yong-gang Lu institute of Systems engineering China Academy of Engineering PhysicsMianyang 621900SichuanChina

Shaped charge warhead is important for enhancing the damage performance of underwater *** paper used finite element analysis software and based on JPC water penetration experiments to examine the influence of liner parameters(wall thickness,material),charge aspect ratio,and stand-off distance on the movement characteristics of JPC in *** findings reveal that the head diameter of the JPC increases and experiences significant erosion after entering the water,the effective length of the JPC in water undergoes two distinct phases:a growth phase and a decrease phase,with the velocity of the JPC decaying *** the liner thickness,stand-off distance and the charge aspect ratio can improve the erosion resistance and the velocity retention capacity of the *** optimal ranges for liner thickness and stand-off distance are 0.0363D_(k) to 0.0545D_(k)(D_(k) is the charge diameter),the stand-off distance should be within 1.0D_(k).After the charge aspect ratio higher than 1.25,the charge structure exerts minimal influence the movement characteristics of the JPC in *** density plays a crucial role in the velocity decay pattern of the JPC during *** with higher densities exhibit superior velocity retention capabilities in water,with the velocity decay pattern converging if the densities are ***,copper,tantalum and tungsten liners are deemed appropriate for underwater shaped charge ***,the results will provide an important reference for the design of underwater shaped charge warhead.

关键词： JPC Movement characteristics Underwater penetration Numerical simulation

Direct visualization of laser-driven dynamic fragmentation in tin by in situ x-ray diffraction

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Matter and Radiation at Extremes 2024年第5期9卷 109-114页

作者： Jing Yang Xinxin Wang Liang Xu Qiannan Wang Yi Sun Jiangtao Li Lin Zhang Yinghua Li Yuying Yu Pei Wang Qiang Wu Jianbo Hu Laboratory for Shock Wave and Detonation physics Institute of Fluid PhysicsChina Academy of Engineering PhysicsMianyang 621900China Laboratory of Computational physics Institute of Applied Physics and Computational MathematicsBeijing 100094China

We present a novel method for investigating laser-driven dynamic fragmentation in tin using in situ X-ray *** experimental results demonstrate the feasibility of the method for simultaneously identifying the phase and temperature of fragments through analysis of the diffraction ***,we observe a deviation from the widely accepted isentropic release assumption,with the temperature of the fragments being found to be more than 100 K higher than expected,owing to the release of plastic work during dynamic *** findings are further verified through extensive large-scale molecular dynamics simulations,in which strain energies are found to be transferred into thermal energies during the nucleation and growth of voids,leading to an increase in *** findings thus provide crucial insights into the impact-driven dynamic fragmentation phenomenon and reveal the significant influence of plastic work on material response during shock release.

关键词： dynamic release diffraction

Programming molecular switches in water and ethanol via thermo-sensitive polymers for phase control in energetic crystals

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Defence Technology（防务技术） 2024年第8期38卷 75-88页

作者： Xinru Yang Yushi Wen Congmei Lin Feiyan Gong Zhijian Yang Fude Nie institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621900China

The practical application of energetic materials, particularly 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20), is frequently impeded by phase transition challenges. In this study, we propose a novel strategy to enhance the stability of CL-20 by employing a thermo-sensitive polymer,poly(N-isopropylacrylamide)(PNIPAM), to modulate its phase transitions. Our approach involves the use of an in-situ polymerized polydopamine(PDA) shell as a platform for surface grafting through atom transfer radical polymerization, yielding a core-shell structured CL-20@PDA-PNIPAM. Through comprehensive characterization, the successful grafting of PNIPAM is confirmed, significantly enhanced the phase stability of CL-20. Notably, our core-shell structure exhibits a 13℃ increase in phase transition temperature compared to raw CL-20, thereby delaying the ε→a phase transition by over 80 min under combined thermal and solvent conditions. The enhanced stability is attributed to the hydrophobic nature of PNIPAM above its low critical solution temperature in water, which effectively shields the CL-20 crystal. These findings provide new insights into enhancing the stability and safety of energetic materials in complex environments, highlighting the potential of our molecular switch mechanism.

关键词： 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20) Phase stability Polydopamine(PDA) Poly-N-Isopropylacrylamide(PNIPAM) Thermal and solvent effects

Gas sensor array based on carbon-based thin-film transistor for selective detection of indoor harmful gases

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Rare Metals 2024年第9期43卷 4401-4411页

作者： Can Liu Yu Sun Jia-Yi Guo Xiu-Lei Li Lu Tao Jin-Yong Hu Jue-Xian Cao Ping-Hua Tang Yong Zhang School of Electrical and Information engineering Hunan Institute of Engineering physics and Optoelectronics&Hunan institute of Advanced Sensing and Information Technology Xiangtan University

The identification of indoor harmful gases is imperative due to their significant threats to human health and *** achieve accurate identification,an effective strategy of constructing a sensor array combined with the pattern recognition algorithm is ***-based thin-film transistors are selected as the sensor array unit,with semiconductor carbon nanotubes （CNTs） within the TFT channels modified with different metals （Au,Cu and Ti） for selective responses to NH3,H2S and HCHO,*** accurate gas species identification,an identification mode that combines linear discriminant analysis algorithms and logistic regression classifier is *** test results demonstrate that by preprocessing the sensor array’s sensing data with the LDA algorithm and subsequently employing the LR classifier for identification,a 100% recognition rate can be achieved for three target gases （NH3,H2S and HCHO）.This work provides significant guidance for future applications of chip-level gas sensors in the realms of the Internet of Things and Artificial Intelligence.

关键词： Carbon-based thin-film transistors Gas sensor arrays Linear discriminant analysis Multi-gas detection Semiconductor carbon nanotubes

Significantly enhanced thermal stability of HMX by phase-transition lysozyme coating

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Defence Technology（防务技术） 2024年第5期35卷 60-68页

作者： Jiahui Liu Congmei Lin Jianhu Zhang Chengcheng Zeng Zhijian Yang Fude Nie institute of Chemical Materials China Academy of Engineering Physics(CAEP)Mianyang 621900China Graduate School China Academy of Engineering Physics(CAEP)Mianyang 621900China

A new robust bio-inspired route by using lysozyme aqueous solution for surface modification on 1,3,5,7-tetranitro-1,3,5,7-tetrazocane(HMX)was described in this *** crystals were coated by in situ phase transition of lysozyme(PTL)*** HMX decorated by PTL was characterized by SEM,XRD,FTIR and XPS,demonstrating a dense core-shell coating *** coverage of lysozyme on HMX crystal was calculated by the ratio of sulfur *** surface coverage increased from 60.5% to 93.5% when the content of PTL was changed from 0.5 wt% to 2.0 wt%,indicating efficient *** thermal stability of HMX was investigated by in situ XRD and *** thermal phase transition temperature of HMX(β to δ phase)was delayed by 42℃ with 2.0 wt% PTL coating,which prevented HMX from thermal damage and sensitivity by the effect of PTL *** heating at 215℃,large cracks appeared in the naked HMX crystal,while the PTL coated HMX still maintained intact,with the impact energy of HMX dropped dramatically from 5 J to 2 ***,the impact energy of HMX with 1.0 wt% and 2.0 wt% coating content(HMX@PTL-1.0 and HMX@PTL-2.0)was unchanged(5 J).Present results potentially enable large-scale fabrication of polymorphic energetic materials with outstanding thermal stability by novel lysozyme coating.

关键词： HMX Lysozyme Phase transition Thermal stability Sensitivity

Footprints of axion-like particle in pulsar timing array data and James Webb Space Telescope observations

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Science China(physics,Mechanics & Astronomy) 2024年第11期67卷 55-62页

作者： Shu-Yuan Guo Maxim Khlopov Xuewen Liu Lei Wu Yongcheng Wu Bin Zhu Department of physics Yantai UniversityYantai 264005 China institute of physics Southern Federal UniversityRostov on Don 344090 Russia National Research Nuclear University MEPhI(Moscow engineering physics institute) Moscow 115409 Russia Virtual institute of Astroparticle physics Paris 75018 France Department of physics and institute of Theoretical physics Nanjing Normal UniversityNanjing 210023 China

Several pulsar timing array(PTA) collaborations have recently reported the evidence for a stochastic gravitational-wave background(SGWB), which can unveil the formation of primordial seeds of inhomogeneities in the early universe. With the SGWB parameters inferred from PTAs data, we can make a prediction of the seeds for early galaxy formation from the domain walls in the axion-like particles(ALPs) field distribution. This also naturally provides a solution to the observation of high redshifts by the James Webb Space Telescope. The predicted photon coupling of the ALP is within the reach of future experimental searches.

关键词： stochastic gravitational-wave background pulsar timing array axion-like particle JWST

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A polarized^(3)He system based on metastability-exchange optical pumping

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Science China(physics,Mechanics & Astronomy) 2024年第7期67卷 72-81页

作者： Yuting Wang Liangyong Wu Kaiyuan Zhang Mei Peng Siyu Chen Haiyang Yan State Key Laboratory of Nuclear physics and Technology School of PhysicsPeking UniversityBeijing 100871China institute of Nuclear physics and Chemistry China Academy of Engineering PhysicsMianyang 621900China Key Laboratory of Nuclear physics and Ion-beam Application(MOE) Fudan UniversityShanghai 200433China Key Laboratory of Neutron physics Institute of Nuclear Physics and ChemistryChina Academy of Engineering PhysicsMianyang 621900China

Hyperpolarized^(3)He nuclei have emerged as a significantly important approach in quantum precision measurement techniques,with extensive applications in fundamental physics,magnetometry,metrology,and *** this study,we report on the design and implementation of a^(3)He polarization system at the China Mianyang Research Reactor(CMRR),utilizing the metastabilityexchange optical pumping(MEOP)*** employed a Merritt coil system consisting of four square coils to furnish a uniform holding *** deployed a 2 W fiber laser to pump the metastable^(3)He atoms and conducted free induction decay(FID)detection of the polarized^(3)He nuclei using both pickup coil and optical *** the optical method,we used a50 m W linearly polarized distributed Bragg reflector(DBR)laser as the *** applied transverse light absorption polarimetry to measure the absolute nuclear polarization of the ground-state^(3)*** have developed cell fabrication capabilities at the CMRR,and cells at various pressures ranging from 100 to 1000 Pa have been fabricated and *** a typical borosilicate cell with 100 Pa pressure,the absolute polarization is measured as Pn≈70%,and the transverse relaxation time is estimated as T2≈0.5 ***,we constructed a few aluminosilicate cells,each carefully filled with pure^(3)He at a pressure of 100 ***,we conducted a comprehensive evaluation of their performance in the context of MEOP.

关键词： metastability exchange optical pumping polarized^(3)He magnetic resonance