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A Multi-faceted View of the X-Ray Spectral Variability in Seyfert Galaxy Ark 120

Research in Astronomy and Astrophysics 2025年第1期25卷 228-239页

作者： Lu-Xin Ren Jun-Xian Wang Jia-Lai Kang CAS Key Laboratory for Research in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of China School of Astronomy and Space Science University of Science and Technology of China

Utilizing a range of techniques including multi-band light curves,softness ratio analysis,structure functions,rms spectra,cross-correlation functions,and ratios of spectra from different intervals,we present a comprehensive study of the complex X-ray spectral variability in Seyfert 1 galaxy Ark 120,through re-analyzing its six XMM-Newton observations taken between 2003 and *** find a clear“softer-when-brighter”trend in the 2–10 ke V power-law component over long timescales,with this trend being timescale dependent,as it is much weaker on shorter timescales,similar to that previously detected in NGC ***,a rare“harder-when-brighter”trend is observed during one exposure,indicating dynamic changes in the spectral variability behavior of the power-law *** exceptional exposure,with the spectral variability indeed marked by a power-law pivoting at an unusually low energy of～2 ke V,suggests intricate variations in the thermal Comptonization processes within the ***,when the data below 2 ke V are included,we identify that the soft excess component adds significant complexity to the spectral variability,such as evidenced by a transition from“harder-when-brighter”to“softer-when-brighter”during another single *** extra complexity arises because the variability of the soft excess sometimes follows and sometimes does not follow the changes in the power-law *** findings underscore the necessity of applying multiple analytic techniques to fully capture the multifaceted spectral variability of AGNs.

关键词： galaxies:active galaxies:Seyfert X-rays:galaxies

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Electronic thermal conductivity of tungsten-based systems during collision cascade processes

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Nuclear science and Techniques 2025年第5期36卷 167-176页

作者： Jiong-Rong Wang Bi-Cai Pan Key Laboratory of Strongly-Coupled Quantum Matter Physics Department of PhysicsUniversity of Science and Technology of ChinaHefei 230026China Hefei National Laboratory for Physical Sciences at Microscale University of Science and Technology of ChinaHefei 230026China

The thermal conductivity of plasma-facing materials(PFM)exposed to intense radiation is a critical concern for the reliable usage of materials in fusion ***,limited research has been performed regarding the thermal conductivity of structures that rapidly change in a short time during collision cascade processes under *** this study,we employed the tight-binding(TB)method to investigate the electronic thermal conductivity(κ_(e))of tungsten-based systems during various cascading *** found thatκ_(e) values sharply decrease within the initial 0.3 picoseconds and then partially recover at a slow pace;this is closely linked to the evolution of defects and microstructural *** increase in the initial kinetic energy of the primary knock-on atom and the presence of a high concentration of hydrogen atoms further decrease theκ_(e) ***,higher temperatures have a significant positive effect onκ_(e).Furthermore,the presence of a grain boundary∑5[001](130)substantially reducesκ_(e),whereas the absorption effect of point defects by the grain boundary has little influence onκ_(e) during *** findings provide a theoretical basis for evaluating changes in the thermal conductivity performance of PFMs during their usage in nuclear fusion reactors.

关键词： Electronic thermal conductivity Collision cascade Tungsten Plasma-facing materials Tight-binding calculations

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Theoretical analysis of the electric potential and the electrostatic dust transport around the Shackleton crater in the Lunar south pole region

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science China Earth sciences 2023年第10期66卷 2278-2286页

作者： Chengxuan ZHAO Hong GAN Lianghai XIE Yi WANG Yongjun WANG Jingyan HONG Science and Technology on Vacuum Technology and Physics Laboratory Lanzhou Institute of PhysicsChina Academy of Space TechnologyLanzhou730000China Space Environment and Payload Engineering Center Lanzhou Institute of PhysicsChina Academy of Space TechnologyLanzhou730000China Deep Space Exploration Laboratory Hefei230026China State Key Laboratory of Space Weather National Space Science CenterChinese Academy of SciencesBeijing100190China Joint Research and Development Center of Chinese Science Academy and Shen County Liaocheng252400China School of Transportation Lanzhou Jiaotong UniversityLanzhou730000China

In recent years,the Lunar south pole region(SPR)has become the focus of future explorations due to its special illumination condition and the possible water ice in permanently shadowed craters around *** Shackleton crater locates almost exactly at the Moon’s south pole and has become the hottest destination for several landing missions,including the Chang’E-7 ***,people still know little about the electric potential and the dust environment around this *** this paper,we develop an analytical model to study the surface potential and the electrostatic dust transport around the *** is found that the crater’s floor can be negatively charged due to the topographic shielding,and the surface potential is as low as-175 V on the leeward crater ***,a large number of charged dust grains can be emitted from the leeward crater wall,with a maximum height of about 10 km and a horizontal distance of about 40 km,which brings a local dust cloud around the *** the topographic shielding and the local dust cloud are qualitatively verified by a numerical simulation,in which a typical dust density of 10^(4)-10^(5)m^(-3)is found near the *** results are important to the environmental assessment for future explorations near the ***,the results are helpful to understand the surface charging and the electrostatic dust transport on the other airless bodies.

关键词： Lunar south pole Lunar crater Solar wind plasma Lunar dust Surface charging

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Van der Waals epitaxial growth of single-crystal molecular film

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National science Review 2024年第11期11卷 194-202页

作者： Lixin Liu Penglai Gong Kailang Liu Bingrong Huang Zhihao Zhang Yingshuang Fu Yu Wu Yinghe Zhao Meihui Wang Yongshan Xu Huiqiao Li Tianyou Zhai State Key Laboratory of Materials Processing and Die &Mould Technology School of Materials Science and EngineeringHuazhong University of Science and Technology Key Laboratory of Optic-Electronic Information and Materials of Hebei Province College of Physics Science and Technology Hebei University Wuhan National High Magnetic Field Center School of Physics Huazhong University of Science and Technology

Epitaxy is the cornerstone of semiconductor technology, enabling the fabrication of single-crystal *** advancements in van der Waals（vd W） epitaxy have opened new avenues for producing wafer-scale single-crystal 2D atomic crystals. However, when it comes to molecular crystals, the overall weak vd W force means that it is a significant challenge for small molecules to form a well-ordered structure during *** we demonstrate that the vd W epitaxy of Sb2O3molecular crystal, where the whole growth process is governed by vd W interactions, can be precisely controlled. The nucleation is deterministically modulated by epilayer–substrate interactions and unidirectional nuclei are realized through designing the lattice and symmetry matching between epilayer and substrate. Moreover, the growth and coalescence of nuclei as well as the layer-by-layer growth mode are kinetically realized via tackling the Schwoebel-Ehrlich barrier. Such precise control of vd W epitaxy enables the growth of single-crystal Sb2O3molecular film with desirable thickness. Using the ultrathin highly oriented Sb2O3film as a gate dielectric, we fabricated MoS2-based field-effect transistors that exhibit superior device performance. The results substantiate the viability of precisely managing molecule alignment in vd W epitaxy, paving the way for large-scale synthesis of single-crystal 2D molecular crystals.

关键词： van der Waals epitaxy inorganic molecular crystal layer-by-layer growth single-crystal film dielectric

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Research on INS/CNS Integrated Navigation Error Model 1

Research on INS/CNS Integrated Navigation Error Model

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1st Aerospace Frontiers Conference, AFC 2024

作者： Bin, Wu Science and Technology on Space Physics Laboratory Beijing100076 China

ISBN: (纸本)9781510681613

The INS/CNS integrated navigation method based on the Strapdown Inertial Measurement Unit and Star Sensor combines the advantages of the two navigation methods, which can achieve high dynamics and high accuracy of integrated navigation. The system error model of traditional INS/CNS integrated navigation strapdown installation needs to linearize the inertial misalignment angle and the installation errors of inertial and star sensors, and establish high-order observation equations. When the installation error is large, it will affect the accuracy of misalignment angle, thereby affecting the effectiveness of integrated navigation. This article focuses on the characteristics of INS/CNS strapdown installation systems and studies a linear error model with only inertial misalignment angle. The effectiveness of the model method is demonstrated through mathematical simulation, and the accuracy of the misalignment angle is calculated. In the process of solving the misalignment angle in this model, there is no need to separate installation errors, which reduces system complexity. © 2024 SPIE.

关键词： Inertial navigation systems

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The biochemical behavior and mechanism of uranium(Ⅵ)bioreduction induced by natural Bacillus thuringiensis

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Journal of Environmental sciences 2024年第2期136卷 372-381页

作者： Shunzhang Chen Junyuan Gong Yanxia Cheng Yuqi Guo Feize Li Tu Lan Yuanyou Yang Jijun Yang Ning Liu Jiali Liao Key Laboratory of Radiation Physics and Technology of the Ministry of Education Institute of Nuclear Science and TechnologySichuan UniversityChengdu 610064China

For a broader understanding of uranium migration affected by microorganisms in natural anaerobic environment,the bioreduction of uranium(Ⅵ)(U(Ⅵ))was revealed in Bacillus thuringiensis,a dominant bacterium strain with potential of uranium-tolerant isolated from uranium contaminated *** reduction behavior was systematically investigated by the quantitative analysis of U(Ⅳ)in bacteria,and mechanism was inferred from the pathway of electron *** anaerobic conditions,appropriate biomass and sodium lactate as electron donor,reduction behavior of U(Ⅵ)induced by *** was restricted by the activity of lactate dehydrogenase,which was directly affected by the initial pH,temperature and initial U(Ⅵ)concentration of bioreduction *** of U(Ⅵ)was driven by the generation of nicotinamide adenine dinucleotide(NADH)from enzymatic reaction of sodium lactate with various *** transmission of the electrons from bacteria to U(Ⅵ)was mainly supported by the intracellular NADH dehydrogenase-ubiquinone system,this process could maintain the biological activity of cells.

关键词： Uranium Bacillus thuringiensis Bioreduction Electron transmission

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Solving Quantum Many-Particle Models with Graph Attention Network

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Chinese physics Letters 2024年第3期41卷 7-14页

作者：于启航林子敬 Department of Physics University of Science and Technology of ChinaHefei 230026China Hefei National Laboratory University of Science and Technology of ChinaHefei 230088China

Deep learning methods have been shown to be effective in representing ground-state wavefunctions of quantum many-body systems,however the existing approaches cannot be easily used for non-square like or large *** propose a variational ansatz based on the graph attention network(GAT)which learns distributed latent representations and can be used on non-square lattices.

关键词： representing variational quantum

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Spin gap in quasi-one-dimensional S=3/2 antiferromagnet CoTi2O5

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Chinese physics B 2024年第3期33卷 609-617页

作者：徐浩航刘庆元辛潮申沁鑫罗军周睿程金光刘健陶玲玲刘志国霍明学王先杰隋郁 School of Physics Harbin Institute of TechnologyHarbin 150001China School of Science Changchun University of Science and TechnologyChangchun 130022China Beijing National Laboratory for Condensed Matter Physics and Institute of PhysicsChinese Academy of SciencesBeijing 100190China Laboratory for Space Environment and Physical Sciences Harbin Institute of TechnologyHarbin 150001China Southwest Institute of Applied Magnetics Mianyang 621000China

Quasi-one-dimensional(1D)antiferromagnets are known to display intriguing phenomena especially when there is a spin gap in their spin-excitation *** we demonstrate that a spin gap exists in the quasi-1D Heisenberg antiferromagnet CoTi2O5 with highly ordered Co2+/Ti4+occupation,in which the Co2+ions with S=3/2 form a 1D spin chain along the ***2O5 undergoes an antiferromagnetic transition at TN~24 K and exhibits obvious anisotropic magnetic susceptibility even in the paramagnetic *** a gapless magnetic ground state is usually expected in a quasi-1D Heisenberg antiferromagnet with half-integer spins,by analyzing the specific heat,the thermal conductivity,and the spin-lattice relaxation rate(1/T1)as a function of temperature,we found that a spin gap is opened in the spin-excitation spectrum of CoTi2O5 around TN,manifested by the rapid decrease of magnetic specific heat to zero,the double-peak characteristic in thermal conductivity,and the exponential decay of 1/T1 below *** the magnetic measurements and the first-principles calculations results indicate that there is spin-orbit coupling in CoTi2O5,which induces the magnetic anisotropy in CoTi2O5,and then opens the spin gap at low temperature.

关键词： quasi-one-dimensional antiferromagnet magnetic anisotropy spin gap

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Experimental and numerical simulation study of the effect for the anode positions on the discharge characteristics of 300W class low power Hall thrusters

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Plasma science and technology 2023年第1期25卷 100-110页

作者：陈新伟高俊杨三祥耿海郭宁顾左杨俊泰张宏 Science and Technology on Vacuum Technology and Physics Laboratory Lanzhou Institute of PhysicsLanzhou 730000People's Republic of China

Low-power Hall thruster(LHT) generally has poor discharge efficiency characteristics due to the large surface-to-volume *** to further refine and improve the performance of 300 W class LHT in terms of thrust and efficiency,and to obtain the most optimal operating point,the experimental study of the discharge characteristics for three different anode positions was conducted under the operation of various discharge voltages(100-400 V) and anode mass flow rates(0.65 mg·s-1and 0.95 mg·s-1).The experimental results indicated that the thruster has the most excellent performance in terms of thrust and efficiency etc at a channel length of 27 mm for identical operating *** addition,particle in cell simulations,employed to reveal the underlying physical mechanisms,show that the ionization and acceleration zone is pushed downwards towards the channel exit as the anode moves towards the *** the identical operating point,when the channel length is reduced from 32 to 27 mm,the ionization and acceleration zone moves towards the exit,and the parameters such as thrust and efficiency increase due to the high ionization rate,ion number density,and axial electric *** the channel length is further moved to 24 mm,the parameters in terms of thrust(F) and efficiency(ηa) are reduced as a result of the decreasing ionization efficiency(ηm) and the larger plume divergence angle(α).In this paper,the results indicated that an optimum anode position(ΔL=27 mm) exists for the optimum performance.

关键词： low-power Hall thruster discharge characteristics PIC-MCC simulation anode positions

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Latitudinal distribution and propagation of lightning-generated whistler:A statistical study by Van Allen Probes observation and ray-tracing simulation

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science China Earth sciences 2025年第4期68卷 1291-1297页

作者： Zhaoguo HE Jiang YU Xiangling DING Zuzheng CHEN Nigang LIU Yuguang YE Jun CUI Qiugang ZONG State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao999078China CNSA Macao Center for Space Exploration and Science Macao999078China Zhuhai MUST Science and Technology Research Institute Macao University of Science and TechnologyZhuhai519000China Planetary Environmental and Astrobiological Research Laboratory(PEARL) School of Atmospheric SciencesSun Yat-sen UniversityZhuhai519000China Institute of Space Physics and Applied Technology Peking UniversityBeijing100871China

Lightning-generated whistler(LGW)is an important electromagnetic wave in the magnetosphere,causing energetic electron *** we analyze the LGW distribution and propagation using Van Allen Probes data and ray-tracing *** statistics show that LGW occurs more frequently at L<2.5 with higher amplitudes in the northern *** Poynting flux demonstrates that LGW originates from both hemispheres within L~2.5,and propagates into the space as the wave power *** wave normal angle distributions indicate that LGW propagates quasi-parallel to the field line near its source and becomes oblique as the magnetic latitude ***,we use the ray-tracing model to simulate the LGW propagation,and statistically analyze the propagation characteristics of LGW,which are consistent with the observational *** paper presents the latitudinal distribution and propagation properties of LGW based on statistics for the first time,providing new insights into the LGW generation and evolution in the magnetosphere.

关键词： Lightning-generated whistler Ray-tracing model Magnetosphere Wave distribution Wave propagation

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