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Effect of order–disorder transition on thermodynamic and electronic properties of σ and χ phases in W–Re alloy: the first-principles calculation

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Tungsten 2025年第1期7卷 195-213页

作者： Zhi-Peng Zhu Dian Jia William Yi Wang Jun-Lei Yin Xing-Yu Gao Shu-Feng Yang Hai-Feng Song Jin-Shan Li State Key Laboratory of Solidification Processing Northwestern Polytechnical University Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

The Tungsten-Rhenium(W-Re) alloys,celebrated for their high melting point,strength at elevated temperatures,electrical resistivity,and radiation resistance,have been widely utilized in high-temperature components,aerospace,electronics,and nuclear *** constituents of the topologically close-packed(TCP) phases,the sigma phase(σ) and chi phase(χ) formed within W-Re alloys wield considerable influence on the mechanical properties and the stability of the *** calculations were utilized in the present work to explore the structural,thermodynamic,and electronic properties of both ordered and disordered configurations within the σ and χ phases,culminating in a systematic elucidation of the higher phase stability exhibited by the ordered *** is found that the bulk modulus of these two phases is directly proportional to the concentration of Re in the alloy,while the equilibrium volume is inversely *** thermodynamic parameters of the σ and χ phases are calculated via the mean-field potential *** similar trends observed in the isobaric heat capacity,enthalpy increment,and entropy change curves for these two phases suggest they possess comparable thermodynamic *** is noteworthy that the contribution of ionic vibrations predominantly affects the isobaric heat capacity,while the contribution of thermal electronic excitations increases linearly with *** the structure and thermodynamic properties of TCP phases in W-Re alloys at low temperatures has profound significance for optimizing material performance,microstructures features,establishing theoretical foundations,and predicting material behavior.

关键词： First-principles calculations Phase stability Thermodynamic properties W-Re alloy TCP phases

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Kinetics of Rayleigh-Taylor instability in van der Waals fluid:the influence of compressibility

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Frontiers of physics 2025年第1期20卷 269-297页

作者： Jie Chen Aiguo Xu Yudong Zhang Dawei Chen Zhihua Chen National Key Laboratory of Transient Physics Nanjing University of Science and TechnologyNanjing 210094China National Key Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsP.O.Box 8009-26Beijing 100088China State Key Laboratory of Explosion Science and Safety Protection Beijing Institute of TechnologyBeijing 100081China HEDPS Center for Applied Physics and Technologyand College of EngineeringPeking UniversityBeijing 100871China National Key Laboratory of Shock Wave and Detonation Physics Mianyang 621999China School of Mechanics and Safety Engineering Zhengzhou UniversityZhengzhou 450001China

Early studies on Rayleigh−Taylor instability(RTI)primarily relied on the Navier−Stokes(NS)*** research progresses,it becomes increasingly evident that the kinetic information that the NS model failed to capture is of great value for identifying and even controlling the RTI process;simultaneously,the lack of analysis techniques for complex physical fields results in a significant waste of data *** addition,early RTI studies mainly focused on the incompressible case and the weakly compressible *** the case of strong compressibility,the density of the fluid from the upper layer(originally heavy fluid)may become smaller than that of the surrounding(originally light)fluid,thus invalidating the early method of distinguishing light and heavy fluids based on *** this paper,tracer particles are incorporated into a single-fluid discrete Boltzmann method(DBM)model that considers the van der Waals *** using tracer particles to label the matter-particle sources,a careful study of the matter-mixing and energy-mixing processes of the RTI evolution is realized in the single-fluid *** effects of compressibility on the evolution of RTI are examined mainly through the analysis of bubble and spike velocities,the ratio of area occupied by heavy fluid,and various entropy generation rates of the *** is demonstrated that:(i)compressibility has a suppressive effect on the spike velocity,and this suppressive impact diminishes as the Atwood number(At)*** influence of compressibility on bubble velocity shows a staged behavior with increasing.(ii)The impact of compressibility on the entropy production rate associated with the heat flow(S_(NOEF))is related to the stages of RTI ***,this staged impact of compressibility on S_(NOEF)varies with *** exhibits an inhibitory effect on the entropy production rate associated with viscous stresses(S_(NOEF)).(iii)By incorporating the morphological parameter of the pr

关键词： discrete Boltzmann method Rayleigh-Taylor instability compressibility effect tracer particles

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Well defined phase boundaries and superconductivity with high T_(c)in PbSe single crystal

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Chinese physics B 2025年第4期34卷 78-84页

作者： Jiawei Hu Yanghao Meng He Zhang Wei Zhong Hang Zhai Xiaohui Yu Binbin Yue Fang Hong Key Laboratory of Materials Physics Institute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 10019China Center for High Pressure Science and Technology Advanced Research Beijing 100094China State Key Laboratory of Superhard Materials International Center for Computational Method and Softwareand Jilin Provincial International Cooperation Key Laboratory of High-Efficiency Clean Energy MaterialsJilin UniversityChangchun 130012China Songshan Lake Materials Laboratory Dongguan 523808China

Lead chalcogenides represent a significant class of materials that exhibit intriguing physical phenomena,including remarkable thermoelectric properties and *** this study,we present a comprehensive investigation on the superconductivity of PbSe single crystal under high *** signature of superconducting(SC)transition starts to appear at 7.2 K under 16.5 *** further compression,the SC temperature(T_(c))decreases,and it is reduced to 3.5 K at 45.0 *** negative pressure dependent behavior of T_(c)is consistent with the trend of T_(c)-P relations observed in other lead *** highest T_(c)is 8.0 K observed at 20.5 GPa during decompression process,which is also the highest record among all other PbSe derivatives,such as doped samples,superlattices,and so *** phase boundaries of the structural and electronic transitions are well defined by Raman spectroscopy,and then phase diagrams are plotted for both compression and decompression *** work corrects the previous claim of positive pressure dependence of T_(c)in PbSe and provides clear phase diagrams for intrinsic superconductivity in PbSe under pressure.

关键词： superconductivity high-pressure electrical transport Raman spectroscopy phase diagrams

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Regulation of graphdiyne-based nanozymes with enhanced oxidaselike activity by cobalt and nitrogen codoping

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Nano Research 2025年第1期18卷 21-29页

作者： Jiali Liu Xiaoli Wang Yongfu Lian Xue Wang Xiuxiu Wang Xingfa Gao Baoyun Sun Xihong Guo CAS Key Laboratory for Biomedical Effects of Nanomaterial&Nanosafety Institute of High Energy PhysicsChinese Academy of ScienceBeijing 100049China Key Laboratory of Functional Inorganic Material Chemistry Ministry of EducationSchool of Chemistry and Materials ScienceHeilongjiang UniversityHarbin 150080China Laboratory of Theoretical and Computational Nanoscience National Center for Nanoscience and TechnologyBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

The development of nanozymes with excellent intrinsic oxidase-like activity and specificity has received increasing ***(GDY)could be a promising choice for designing nanozymes with enhanced oxidase(OXD)-like activity due to its unique structure and ***,Co-N-GDY with high OXD activity but no peroxidase(POD)activity was synthesized by codoping of cobalt(Co)and nitrogen(N)into GDY and compared with other GDY-based nanozymes(including GDY,Co-GDY,and N-GDY).Upon analyzing the doping effect of Co and N on the OXD-like and POD-like activities,we found that the combination of Co and N in GDY played a significant role in enhancing the OXD-like activity,and even reversed the POD-like activity of N-GDY to OXD-like activity of *** electrochemical experiment and the theoretical calculations provided an explanation for the mechanism and showed that the activity was closely linked to the reduction ability of O_(2) or H_(2)O_(2) on the nanozyme substrates,which was determined by the ratedetermining step of the catalytic reaction.

关键词： nanozymes oxidase-like activity graphdiyne heteroatom doping regulation

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Formation mechanism of multiple spallation and its penetration induced by shear localization in NiTi alloy under implosion loading

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Matter and Radiation at Extremes 2025年第1期10卷 81-97页

作者： Xianye Wu Xiaoyang Pei Xiang Chen Hao Zhang Jin Wang Xin Yang Meizhen Xiang Shang Gao Fang Wang School of Materials and Energy Southwest UniversityChongqing 400715China Institute of Fluid Physics China Academy of Engineering PhysicsMianyang 621999China State Key Laboratory of Nuclear Physics and Technology Center for Applied Physics and TechnologyPeking UniversityBeijing 100871China School of Environment and Resource Southwest University of Science and TechnologyMianyang 621010China Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China

This study uses nonequilibrium molecular dynamics simulations to explore the dynamic failures and deformation mechanisms of a cylindrical shell composed of nanocrystalline nickel-titanium alloy under implosion *** discover that some individual spall planes are sequentially generated in the material along the propagation of a radial stress wave,indicative of the formation of multiple *** larger grain sizes,void nucleation at the first spallation occurs in a coexisting intergranular/transgranular manner,whereas with decreasing grain size,voids tend to nucleate along the grain ***,the spall strength exhibits a transition from an inverse Hall-Petch to a Hall-Petch *** larger grain sizes,at the secondary spallation,localized shearing zones and grain boundaries provide potential void-nucleated ***,the formation of shear deformation bands promotes grain refinement,contributing to a reduction in the dislocation-induced strengthening ***,a lower spall strength is produced,in contrast to the first *** the grain size becomes smaller,voids nucleate mostly along grain boundaries,and plastic deformation is dominated by dense grain ***,the high temperature caused by shear localization leads to material weakening,and in turn there is a significant decrease in the spall strength for the secondary spallation,compared with the ***,significant penetration between two spall planes is observed for large grain size,which can be attributed to the nucleation of voids on linking grain boundaries,with temperatures exceeding the melting point of the material.

关键词： grain alloy deformation

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Unravelling the Electrocatalytic Activity of LaFeO3 Perovskite towards O2 Reduction Reaction

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Energy and Fuels 2025年第19期39卷 9066-9080页

作者： Khatri, Kashika Sharma, Naveen Joshi, Himani Pakhira, Srimanta Theoretical Condensed Matter Physics & Advanced Computational Materials Science Laboratory Department of Physics Indian Institute of Technology Indore Khandwa Road Simrol MP Indore453552 India Indian Institute of Technology Indore Khandwa Road Simrol MP Indore453552 India

The oxygen reduction reaction (ORR) plays a vital role in renewable energy technologies, such as fuel cells. The performance of solid-polymer-electrolyte fuel cells depends on sluggish ORR kinetics, which poses a key challenge. To address this issue, extensive research has been conducted to explore non-Pt-based materials as potential alternatives for enhancing the ORR performance. In the present study, we theoretically investigated the structural and electronic properties of bulk LaFeO3 perovskite using the GGA+U approach within the Vienna Ab Initio Simulation Package (VASP) framework. A (001) plane was cleaved from the bulk LaFeO3 material to model a 2D monolayer of LaFeO3, which was found to exhibit a band gap of 0 eV, indicating its potential to be used as an electrocatalyst for fuel cell applications. The complete ORR pathway was explored on the surface of the 2D monolayer LaFeO3 perovskite. Both the associative and dissociative reaction mechanisms were studied by computing the change in Gibbs free energy (ΔG) for all of the reaction steps involved in ORR. Our findings demonstrate that the 2D LaFeO3 monolayer exhibits exceptional electrocatalytic activity and favors the four-electron associative mechanism over the dissociative one. This study proposes that the 2D monolayer of LaFeO3 can serve as an alternate ORR electrocatalyst to expensive platinum in fuel cells. Overall, these results offer insights into the potential application of the subject perovskite as a fuel cell material and provide profound insight into the O2 reduction process on 2D perovskite-derived catalysts, including interactions with residual H2O during the reaction, while also shedding light on the properties and behavior of active sites. © 2025 American Chemical Society.

关键词： Electrolytic reduction

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Structural engineering of MXenes for enhanced magnesium ion diffusion: a computational study

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RSC Advances 2025年第20期15卷 16219-16227页

作者： Ma, Mingxiao Yao, Xiangyu Wang, Jianglong Shi, Xingqiang Wang, Ruining Lian, Ruqian Kan, Dongxiao Jing, Chenyang Key Laboratory of Optic-Electronic Information and Materials of Hebei Province Hebei Research Center of the Basic Discipline for Computational Physics College of Physics Science and Technology Hebei University Baoding071002 China Northwest Institute for Non-ferrous Metal Research Xi'an710016 China

The unique layered structure and tunable surface terminations of MXenes play a critical role in Mg2+ storage and diffusion dynamics. This study systematically investigates the behavior of Mg2+ in Ti3C2O2 and its nitrogen-doped derivatives through theoretical calculations. In Ti3C2O2 monolayers, Mg2+ exhibits a high diffusion barrier of 0.81 eV due to strong electrostatic interactions. However, AA-stacking reduces this barrier to 0.32 eV by introducing staggered active sites. The instability caused by interlayer O-O repulsion is mitigated by modulating the N/O ratio (Ti3C2O1.78N0.22), resulting in a diffusion barrier of 0.27 eV. Transition metal substitution further optimizes performance, as exemplified by Nb3C2N2, which achieves an ultralow barrier of 0.23 eV through weakened N-N covalency and enhanced metal-N interactions. Voltage analysis reveals that Nb3C2N2 possesses dual functionality as both cathode (4.00 V) and anode (0.64 V), contrasting with the anode-specific behavior observed in Ti-based MXenes. © 2025 The Royal Society of Chemistry.

关键词： Nitrides

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Theoretical insight into stabilities and optoelectronic properties of RbZnX3 (X=Cl, Br) halide perovskites for energy conversion applications

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Optical and Quantum Electronics 2025年第1期57卷 1-21页

作者： Khan, Naimat Ullah Ghani, Usman khan, Arshad Khan, Asif Nawaz Ullah, Khadim Ali, Roshan Fadhali, Mohammed M. Department of Physics Materials Modeling and Simulation Lab University of Science & Technology Bannu Khyber Pakhtunkhwa Bannu28100 Pakistan Department of Physics University of Science & Technology Bannu Khyber Pakhtunkhwa Bannu28100 Pakistan Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory College of Physical Sciences University of Chinese Academy of Sciences Beijing100049 China Department of Physical Sciences Physics Division College of Science Jazan University P.O. Box. 114 Jazan45142 Saudi Arabia

Owing to the interesting physical characteristics of perovskites, herein, we investigate RbZnX3 (X = Cl, Br) halide perovskites for sustainable green energy applications. All the given structures were made relaxed and minimum energy was attained by employing Birch-Muranghan equation of state. The electronic band structure of the under study materials were calculated through modified-Beck-Johnson potential. Our results showed that all the investigated RbZnX3 (X = Cl, Br) perovskites are semiconductors with band gaps of 1.34, and 0.12 eV, respectively. The calculated tolerance factors, formation energies, Born-Hung criteria, phonon spectra and ab initio molecular dynamic (AIMD) simulations demonstrated that the given compounds exhibit geometrical, thermodynamic, mechanical, dynamic and thermal stabilities. Findings of elastic investigation revealed an elastic, anisotropic, and ductile nature of our predicted compounds. Moreover, all the studied materials revealed strong absorption – 104 cm−1 in the visible and ultraviolet spectrum and the device absorption efficiency (%) was found comparable to other known reported materials. Overall, this study demonstrates that our simulated perovskites are suitable candidates for photovoltaic and optoelectronic applications. © The Author(s), under exclusive licence to Springer science+Business Media, LLC, part of Springer Nature 2025.

关键词： Bromine compounds

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Crystalline-symmetry-protected Majorana modes in coupled quantum dots

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Physical Review Research 2025年第1期7卷 L012022-L012022页

作者： Bradraj Pandey Gonzalo Alvarez Elbio Dagotto Rui-Xing Zhang Department of Physics and Astronomy The University of Tennessee Knoxville Tennessee 37996 USA Materials Science and Technology Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA Computational Sciences and Engineering Division Oak Ridge Tennessee 37831 USA Department of Materials Science and Engineering The University of Tennessee Knoxville Tennessee 37996 USA

We propose a minimalist architecture for achieving various crystalline-symmetry-protected Majorana modes in an array of coupled quantum dots. Our framework is motivated by the recent experimental demonstrations of two-site and three-site artificial Kitaev chains in a similar setup. We find that introducing a π-phase domain wall in the Kitaev chain leads to a pair of mirror-protected Majorana zero modes located at or near the junction. Joining two π junctions into a closed loop, we can simulate two distinct classes of two-dimensional higher-order topological superconducting phases, both carrying symmetry-protected Majorana modes around the sample corners. As an extension of the π junction, we further consider a general vertex structure where n Kitaev chains meet, i.e., a Kitaev n vertex. We prove that such an n vertex, if respecting a dihedral symmetry group Dn, necessarily carries n vertex-bound Majorana modes protected by the Dn symmetry. Resilience of the junction and vertex Majorana bound states against disorder and correlation effects is also discussed. Our architecture paves the way for designing, constructing, and exploring a wide variety of artificial topological crystalline phases in quantum-dot experiments.

关键词： Crystalline materials

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Predictions of H-mode access and edge pedestal instability in the EHL-2 spherical torus

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Plasma science and technology 2025年第2期27卷 54-63页

作者： Yumin WANG Kai LI Zhuo HUANG Yiliang LIU Shuyu DAI Jie ZHANG Yanqing HUANG Xiang GU Yihang ZHAO Shuai XU Erhui WANG Dong GUO Yuejiang SHI Huasheng XIE Yunfeng LIANG Minsheng LIU the EHL-2 Team Hebei Key Laboratory of Compact Fusion Langfang 065001People’s Republic of China ENN Science and Technology Development Co. Ltd.Langfang 065001People’s Republic of China Centre for Theoretical and Computational Physics College of PhysicsQingdao UniversityQingdao 266071People’s Republic of China College of Computer Science South-Central Minzu UniversityWuhan 430074People’s Republic of China Key Laboratory of Materials Modification by Laser Ion and Electron Beams(Ministry of Education)School of PhysicsDalian University of TechnologyDalian 116024People’s Republic of China Department of Plasma Physics and Fusion Engineering University of Science and Technology of ChinaHefei 230026People’s Republic of China College of Physics and Electronic Engineering Hengyang Normal UniversityHenyang 421002People’s Republic of China Forschungszentrum Jülich GmbH Institute of Fusion Energy and Nuclear Waste Management-PlasmaphysikJülich 52425Germany

The EHL-2 spherical torus is designed to demonstrate proton-boron(p-11B)fusion within a compact spherical *** planned heating system includes a negative ion-based neutral beam injection(N-NBI),two positive ion-based NBI systems(P-NBI),electron cyclotron resonance heating(ECRH),ion cyclotron resonance heating(ICRH),and high harmonic fast wave(HHFW),with a total power output of 31 *** to scaling law estimates,the device is capable of achieving H-mode *** plasma density,,n_(e,min)at the minimum L-H power threshold,P_(lh),is estimated to be 4.4×10^(19)m^(-3).The pedestal parameters were calculated using the REPED *** B as the primary impurity ion,the predicted pedestal width and height are lower compared to the typical case with carbon *** pedestal collisionality for EHL-2 is estimated to range between 0.06 and 0.17,indicating the potential for significant energy loss due to edge localized modes(ELMs).The heat flux on the divertor plate has been calculated using the JOREK *** peak heat fluxes during ELM bursts are approximately 31.0 MW/m^(2)at the lower inboard target and 39.5 MW/m^(2)at the lower outboard target.A preliminary design of the resonant magnetic perturbation(RMP)coils has been completed to both control type-I ELMs and correct error *** system comprises 16 coils arranged into 24 *** ELM control mode,a 14/2 component is generated at 1.7 G/kAt,with a current of 4.9 kA required to achieveσChirikow=1 at the resonant surface,where the normalized poloidal magnetic flux is *** error field(EF)modulation mode,2/1 and 3/1 components are generated at 3.5 G/kAt and 2.8 G/kAt,respectively.

关键词： H-mode spherical torus(ST) EHL-2 pedestal resonant magnetic perturbations

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