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Communications in Theoretical physics 2024年第2期76卷 151-156页

作者： Marjan Zakavi Mohammad Sabaeian Department of physics Faculty of ScienceShahid Chamran University of AhvazIran Center for Research on Laser and Plasma Shahid Chamran University of AhvazIran

In this study,we successfully extracted the‘knee structure’for non-sequential double ionization(NSDI)in the helium *** achieve this,for the first time,we solved the time-dependent Schrödinger equation in three dimensions for the helium atom,utilizing the shielding charge *** findings corroborate prior observations by Wang et al[Wang and Eberly,***.105,083001(2010)],demonstrating that NSDI occurs within a narrower time window in circular polarization compared to linear *** a result,the yield of linear polarization was higher than that of circular polarization,aligning with the previously reported ***,in the case of circular polarization,the time window further narrows with increasing intensity,attributed to a decrease in the time-of-flight.

关键词： NSDI knee structure TDSE shielding charge helium 3D-TDSE

Spectral observation of symmetry-protected selection rules for dynamical high-dimensional parity in alignment magnetic resonance

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science China(physics,Mechanics & Astronomy) 2024年第10期67卷 1-11页

作者： Xu-Xing Geng Kai Jin Lu Zhou Wang-Wang Tang Guoqing Yang Shangqing Liang Shao-Ping Wu Guang-Ming Huang Gao-Xiang Li Department of physics Huazhong Normal UniversityWuhan 430079China College of electronics and Information Hangzhou Dianzi UniversityHangzhou 310018China State Key Laboratory of Precision Spectroscopy School of Physics and Electronic ScienceEast China Normal UniversityShanghai 200241China

Multidimensional Floquet-driven alignment systems with dynamical symmetry present various exotic phenomena and ***,there are challenges in directly characterizing large-spin dynamical symmetry from ***,we first observe the symmetry-protected selection rules of dynamical high-dimensional parity in a large-spin(F=4)*** theoretically construct a Floquet-driven alignment system that can be used to reveal high-dimensional spatiotemporal *** the experiment,the system is implemented in Cs atomic gas subjected to two-dimensional Floquet-modulated magnetic resonance *** developing Floquet detection protocols of alignment double-sided spectra,we directly verify symmetry-protected selection rules of dynamical high-dimensional parity for large-spin *** work advances the exploration of dynamical symmetry to large spins,and unravels a universal Floquet scheme for the investigation of symmetry-protected selection rules.

关键词： dynamical high-dimensional symmetry symmetry-protected selection rules large-spin alignment magnetic resonance,Floquet two-mode detection

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Unraveling the modulation essence of p bands in Co-based oxide stability on acidic oxygen evolution reaction

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Nano Research 2024年第7期17卷 5922-5929页

作者： Yafei Yang Yihao Xu Haiquan Liu Qi Zhang Boling Liu Menghua Yang Huan Dai Zunjian Ke Dong He Xiaobo Feng Xiangheng Xiao Department of physics Zhongnan Hospital of Wuhan UniversityWuhan UniversityWuhan 430072China School of physics and electronic Information Yunnan Normal UniversityKunming 650500China Yunnan Key Laboratory of Opto-electronic Information Technology Kunming 650500China

The oxygen evolution reaction(OER)electrocatalysts,which can keep active for a long time in acidic media,are of great significance to proton exchange membrane water ***,Ru-Co_(3)O_(4)electrocatalysts with transition metal oxide Co_(3)O_(4)as matrix and the noble metal Ru as doping element have been prepared through an ion exchange–pyrolysis process mediated by metal-organic framework,in which Ru atoms occupy the octahedral sites of Co_(3)O_(4).Experimental and theoretical studies show that introduced Ru atoms have a passivation effect on lattice *** strong coupling between Ru and O causes a negative shift in the energy position of the O p-band ***,the bonding activity of oxygen in the adsorbed state to the lattice oxygen is greatly passivated during the OER process,thus improving the stability of matrix *** addition,benefiting from the modulating effect of the introduced Ru atoms on the metal active sites,the thermodynamic and kinetic barriers have been significantly reduced,which greatly enhances both the catalytic stability and reaction efficiency of Co_(3)O_(4).

关键词： p-band modulation oxygen evolution reaction stability acidic oxygen evolution reaction(OER)

A statistical analysis of the Kappa-type energy spectrum distribution of radiation belt electrons observed by Van Allen Probes

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Earth and Planetary physics 2024年第2期8卷 368-374页

作者： LuHuai Jiao Xin Ma YuanNong Zhang TaiFeng Jin Song Fu BinBin Ni Department of Space physics School of Electronic InformationWuhan UniversityWuhan 430072China

The energy spectrum of energetic electrons is a key factor representing the dynamic variations of Earth’s Van Allen radiation *** measurements have indicated that the commonly used Maxwellian and Kappa distributions are inadequate for capturing the realistic spectral distributions of radiation belt *** we adopt the Kappa-type(KT)distribution as the fitting function and perform a statistical analysis to investigate the radiation belt electron flux spectra observed by the Van Allen *** calculating the optimal values of the key KT distribution parameters(i.e.,κandθ2)from the observed spectral shapes,we fit the radiation belt electron fluxes at different L-shells under different geomagnetic *** this manner,we obtain typical values of the KT distribution parameters,which are statistically feasible for modeling the radiation belt electron flux profiles during either geomagnetically quiet or active periods.A comparison of the KT distribution model results with those using the Maxwellian or Kappa distribution reveals the advantage of the KT distribution for studying the overall properties of the radiation belt electron spectral distribution,which has important implications for deepening the current understanding of the radiation belt electron dynamics under evolving geomagnetic conditions.

关键词： radiation belt electron Kappa-type distribution fitting geomagnetic storm

Effect of interplanetary magnetic field B_(x)on the polar electrojets as observed by CHAMP and Swarm satellites

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Earth and Planetary physics 2024年第2期8卷 382-390页

作者： Hui Wang ChengZhi Wang YunFang Zhong Department of Space physics School of Electronic InformationWuhan UniversityWuhan 430072China

Based on 16 years of magnetic field observations from CHAMP and Swarm satellites,this study investigates the influence of the Interplanetary Magnetic Field(IMF)Bx component on the location and peak current density of the polar electrojets(PEJs).We find that the IMF Bx displays obvious local time,seasonal,and hemispherical effects on the PEJs,as follows:(1)Compared to other local times,its influence is weakest at dawn and dusk.(2)In the midnight sectors of both hemispheres,the IMF Bx tends to amplify the westward PEJ when it is0 in the Southern Hemisphere;this effect is relatively stronger in the local winter hemisphere.(3)At noontime,the IMF Bx intensifies the eastward current when it is0,it reduces the westward current;this effect is notably more prominent in the local summer hemisphere.(4)Moreover,the noontime eastward current shifts towards higher latitudes,while the midnight westward current migrates towards lower latitudes when IMF Bx is0 in the Southern Hemisphere.

关键词： polar electrojet interplanetary magnetic field Bx local time asymmetry hemispheric difference

DFT investigation of half-metallic ferromagnetic rare earth based spinels MgHo_(2)Z_(4)(Z=S,Se)

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Journal of Rare Earths 2024年第1期42卷 121-128,I0005页

作者： Maiza Zanib Mumtaz Manzoor N.A.Noor M.Waqas Iqbal Mazia Asghar H.H.Hegazy A.Laref Department of physics Riphah International UniversityLahore CampusPakistan Research Centre for Advanced Materials science King Khalid UniversityP.O.Box 9004AbhaSaudi Arabia Department of physics Faculty of ScienceKing Khalid UniversityP.O.Box 9004AbhaSaudi Arabia Department of physics and Astronomy College of ScienceKing Saud UniversityRiyadh11451Saudi Arabia

Half-metallic ferromagnetism,mechanical as well as thermoelectric properties for rare earth-based spinels MgHo_(2)Z_(4)(Z=S,Se)were investigated using density functional theory(DFT).Structural optimization was done with Perdew-Burke-Ehrenzorf(PBE)sol-generalized gradient approximation(GGA)to calculate the lattice constant of both spinels comparable to experimental *** addition,Born stability criteria and negative formation energy show that our studied spinels are also structurally and dynamically stable in the cubic *** ferromagnetic(FM)state stability,we also calculated the energy differences among FM,antiferromagnetic(AFM),and non-magnetic(NM)***,Curie temperatures of ferromagnetic phases were also *** used Trans-Blaha improved BeckeJohnson(TB-mBJ)potential functional for electronics as well as magnetic characteristics,which lead to the consistent explanation of half-metallic ferromagnetism,representing the whole band-occupancy in material with exact detail of density of states(DOS).The stable FM state was examined in spinels due to the exchange splitting of Ho cation consisting of p-d hybridizations compatible with the result achieved for electronics band structure and ***,spin magnetic moment was explained in terms of anion,cation,and sharing charge on studied *** addition,the calculated thermoelectric properties clearly show that operation range of these systems may be utilized by future experimental works for identifying the potential applications of these systems.

关键词： Ho-based spinels DFT simulations Mechanical parameters electronic properties HM ferromagnetism Figure of merit

Acoustic Bilayer Gradient Metasurfaces for Perfect and Asymmetric Beam Splitting

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Chinese physics Letters 2024年第1期41卷 39-50页

作者：权家琪孙宝印伏洋洋高雷徐亚东 Institute of Theoretical and Applied physics School of Physical Science and TechnologySoochow UniversitySuzhou 215006China College of physics Nanjing University of Aeronautics and Astronautics&Key Laboratory of Aerospace Information Materials and Physics(NUAA)MIITNanjing 211106China School of Optical and electronic Information Suzhou City UniversitySuzhou 215104China

We experimentally and theoretically present a paradigm for the accurate bilayer design of gradient metasurfaces for wave beam manipulation,producing an extremely asymmetric splitting effect by simply tailoring the interlayer *** concept arises from anomalous diffraction in phase gradient metasurfaces and the precise combination of the phase gradient in bilayer *** by different diffraction routes in momentum space for incident beams from opposite directions,extremely asymmetric acoustic beam splitting can be generated in a robust way,as demonstrated in experiments through a designed bilayer *** work provides a novel approach and feasible platform for designing tunable devices to control wave propagation.

关键词： surfaces splitting asymmetric

Overshoot phenomena:Observation and simulation

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Earth and Planetary physics 2024年第2期8卷 391-399页

作者： Ting Feng MoRan Liu ShiMin He Xiang Wang Chen Zhou Department of Space physics School of Electronic InformationWuhan UniversityWuhan 430072China

High-power O-mode radio waves can excite artificial instabilities in the F region,according to experiments conducted at the European Incoherent Scatter science Association(EISCAT)heating *** main instabilities include the parametric decay instability(PDI),oscillating two-stream instability(OTSI),and thermal parametric instability(TPI).The PDI and OTSI not only compete with each other,but also compete with the TPI,leading to a two-stage overshoot phenomenon:a miniovershoot occurs on a millisecond time scale after pump-on,followed by the main *** gain insight into the miniovershoot via a generalized Zakharov model,whereas the main overshoot can be observed as an enhanced plasma line overshoot phenomenon in incoherent scatter radar *** can also observe that the zero-frequency ion line exists only in the initial heating period after a cold start and that the upshifted and downshifted ion lines behave irregularly in the *** simulation results show that competition between the PDI and OTSI leads to an initial peak,which we named the *** following processes,namely ion density caviton generation,and collapse and cascade in the development of the PDI,contribute to the miniovershoot phenomenon.

关键词： overshoot parametric decay instability oscillating two-stream instability competition

Emergent topological ordered phase for the Ising-XY model revealed by cluster-updating Monte Carlo method

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Chinese physics B 2024年第4期33卷 386-400页

作者：马赫阳张万舟田彦婷丁成祥邓友金 College of physics Taiyuan University of TechnologyTaiyuan 030024China Hefei National Laboratory for Physical sciences at the Microscale and Department of Modern physics University of Science and Technology of ChinaHefei 230026China School of Microelectronics&Data science Anhui University of TechnologyMaanshan 243002China Minjiang Collaborative Center for Theoretical physics College of Physics and Electronic Information EngineeringMinjiang UniversityFuzhou 350108China Shanghai Research Center for Quantum sciences Shanghai 201315China

The two-component cold atom systems with anisotropic hopping amplitudes can be phenomenologically described by a two-dimensional Ising-XY coupled model with spatial *** low temperatures,theoretical predictions[***.A 72053604(2005)]and[arXiv:0706.1609]indicate the existence of a topological ordered phase characterized by Ising and XY disorder but with 2XY ***,due to ergodic difficulties faced by Monte Carlo methods at low temperatures,this topological phase has not been numerically *** propose a linear cluster updating Monte Carlo method,which flips spins without rejection in the anisotropy limit but does not change the *** this scheme and conventional Monte Carlo methods,we succeed in revealing the nature of topological phases with half-vortices and domain *** the constructed global phase diagram,Ising and XY-type transitions are very close to each other and differ significantly from the schematic phase diagram reported *** also propose and explore a wide range of quantities,including magnetism,superfluidity,specific heat,susceptibility,and even percolation susceptibility,and obtain consistent and reliable ***,we observed first-order transitions characterized by common intersection points in magnetizations for different system sizes,as opposed to the conventional phase transition where Binder cumulants of various sizes share common *** critical exponents of different types of phase transitions are reasonably *** results are useful to help cold atom experiments explore the half-vortex topological phase.

关键词： topological phase transition Ising-XY model Monte Carlo method half vortex

Guest Editorial:Special issue on advances in representation learning for computer vision

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CAAI Transactions on Intelligence Technology 2024年第1期9卷 1-3页

作者： Andrew Beng Jin Teoh Thian Song Ong Kian Ming Lim Chin Poo Lee Electrical and electronic Engineering Department Yonsei UniversitySeoulSouth Korea faculty of Information science and Technology Multimedia UniversityMelakaMalaysia

Deep learning has been a catalyst for a transformative revo-lution in machine learning and computer vision in the past *** these research domains,methods grounded in deep learning have exhibited exceptional performance across a spectrum of *** success of deep learning methods can be attributed to their capability to derive potent representations from data,integral for a myriad of downstream *** representations encapsulate the intrinsic structure,fea-tures,or latent variables characterising the underlying statistics of visual *** these achievements,the challenge per-sists in effectively conducting representation learning of visual data with deep models,particularly when confronted with vast and noisy *** special issue is a dedicated platform for researchers worldwide to disseminate their latest,high-quality articles,aiming to enhance readers'comprehension of the principles,limitations,and diverse applications of repre-sentation learning in computer vision.

关键词： spite computer representation