检索结果-南通市图书馆

Emergent symmetry in quantum phase transition:From deconfined quantum critical point to gapless quantum spin liquid

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2024年第2期69卷 190-196页

作者： Wen-Yuan Liu Shou-Shu Gong Wei-qiang Chen zheng-Cheng Gu Department of Physics The Chinese University of Hong KongHong KongChina Division of Chemistry and Chemical Engineering California Institute of TechnologyPasadena CA 91125USA School of Physical Sciences Great Bay UniversityDongguan 523000China Great Bay Institute for Advanced Study Dongguan 523000China Department of Physics and Shenzhen Institute for Quantum Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices Southern University of Science and TechnologyShenzhen 518055China

The emergence of exotic quantum phenomena in frustrated magnets is rapidly driving the development of quantum many-body physics,raising fundamental questions on the nature of quantum phase transitions.Here we unveil the behaviour of emergent symmetry involving two extraordinarily representative phenomena,i.e.,the deconfined quantum critical point(DQCP)and the quantum spin liquid(QSL)state.Via large-scale tensor network simulations,we study a spatially anisotropic spin-1/2 square-lattice frustrated antiferromagnetic(AFM)model,namely the J1x-J1y-J2 model,which contains anisotropic nearestneighbor couplings J1x,J1y and the next nearest neighbor coupling J2.For small J1y/J1x,by tuning J2,a direct continuous transition between the AFM and valence bond solid phase is observed.With growing J1y/J1x,a gapless QSL phase gradually emerges between the AFM and VBS phases.We observe an emergent O(4)symmetry along the AFM–VBS transition line,which is consistent with the prediction of DQCP theory.Most surprisingly,we find that such an emergent O(4)symmetry holds for the whole QSL–VBS transition line as well.These findings reveal the intrinsic relationship between the QSL and DQCP from categorical symmetry point of view,and strongly constrain the quantum field theory description of the QSL phase.The phase diagram and critical exponents presented in this paper are of direct relevance to future experiments on frustrated magnets and cold atom systems.

关键词： Tensor network Quantum phase transition Emergent symmetry Quantum spin liquid Deconfined quantum critical point Anisotropic

Deciphering dynamic surface of PtRu alloy nanocatalysts to revisit their synergistic effects during the electrooxidation

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第7期67卷 2224-2233页

作者： Xiao-Chong Li Bo Wang Zhou Yu qiang Wan Ju-Fang zheng Emmanuel Maisonhaute Xiao-Shun Zhou ya-Hao Wang Key Laboratory of the Ministry of Education for Advanced Catalysis Materials Institute of Physical ChemistryZhejiang Normal UniversityJinhua 321004China Laboratoire Interface et Systèmes Electrochimiques CNRS UMR 8235Sorbonne UniversitéF-75252 Paris cedex 5France

Correlating dynamic structural transformation of catalysts with the surface intermediate species under operating conditions is critical for updating the understanding of structure–performance relationships.Here,we probe the electrochemical potentialdependent surface structures and adsorbed intermediates on PtRu binary alloy nanocatalysts to revisit its synergistic mechanisms for CO electrooxidation enhanced activity.In-situ spectral characteristics by using modified shell-isolated nanoparticle-enhanced Raman spectroscopy,show that in acidic solution,when the potential is positively scanned from 0.1 V to 1.5 V relative to reversible hydrogen electrode(RHE),the surface of the alloy catalyst evolves from metallic PtRu to adsorbed oxygen gradually covering and accumulating on Ru sites(denoted as PtRuO_(x),x≤2),forming segregated RuO_(2),and finally forming a threedimensional oxide layer(denoted as 3D PtRuO_(4)).Moreover,molecular evidence associated with periodic density functional theory calculations reveals that electronic effects promote ruthenium to become more oxidizable and oxophilic.In particular,we found here that*O and*OH at surface RuOxsites are highly efficient CO oxidation active species in comparison to the same entities adsorbed on metallic Ru sites.This work sheds light on the complex surface dynamic process of practical Pt-based binary nanocatalysts and improves the understanding of synergistic mechanism for the development of fuel cell devices.

关键词： in-situ Raman spectroscopy surface evolution bifunctional mechanism PtRu electrooxidation

Mechanical property of cylindrical sandwich shell with gradient core of entangled wire mesh

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第1期31卷 510-522页

作者： Xin Xue Chao zheng Fu-qiang Lai Xue-qian Wu Institute of Metal-rubber&Vibration Noise School of Mechanical Engineering and AutomationFuzhou UniversityFuzhou350116China Fujian Metallurgical Industry Design Institute Fuzhou350116China

To explore the wide-frequency damping and vibration-attenuation performances in the application of aerospace components,the cylindrical sandwich shell structure with a gradient core of entangled wire mesh was proposed in this paper.Firstly,the gradient cores of entangled wire mesh in the axial and radial directions were prepared by using an in-house Numerical Control weaving machine,and the metallurgical connection between skin sheets and the gradient core was performed using vacuum brazing.Secondly,to investigate the mechanical properties of cylindrical sandwich shells with axial or radial gradient cores,quasi-static and dynamic mechanical experiments were carried out.The primary evaluations of mechanical properties include secant stiffness,natural frequency,Specific Energy Absorption(SEA),vibration acceleration level,and so on.The results suggest that the vibration-attenuation performance of the sandwich shell is remarkable when the high-density core layer is at the end of the shell or abuts the inner skin.The axial gradient material has almost no influence on the vibration frequencies of the shell,whereas the vibration frequencies increase dramatically when the high-density core layer approaches the skin.Moreover,compared to the conventional sandwich shells,the proposed functional grading cylindrical sandwich shell exhibits more potential in mass reduction,stiffness designing,and energy dissipation.

关键词： Entangled wire mesh Gradient cylindrical sandwich shell Vacuum brazing Secant stiffness Damping

Anti-corrosive and highly reversible zinc metal anode enabled by the phenolic resin coating

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第5期43卷 2115-2124页

作者： ya-Ping Wang ya-Di yang Shu-Qi Duan Li Wang Jia-Shuo Guo An-qiang Pan School of Materials Science and Engineering Hebei University of Technology Key Laboratory of Special Functional Materials for Ecological Environment and Information (Hebei University of Technology) Ministry of Education Key Laboratory for New Type of Functional Materials in Hebei Province Hebei University of Technology School of Materials Science and Engineering Central South University

Aqueous zinc-ion batteries have attracted much attention due to their high theoretical capacity,low cost high safety,and eco-friendly.However,challenges such as dendrite growth and side reactions severely hinder the electrochemical performance of the Zn anode,leading to low Coulombic efficiency （CE） or even short circuits Herein,phenolic resin （PF） is used as a protective coating on the surface of the zinc metal electrode.The PF layer can greatly improve the corrosion resistance of the Zn electrode in the electrolyte.Importantly,this artificial electrode/electrolyte interphase also elevates the nucleation barrier and restrains Zn2+2D diffusion,regulating the zinc deposition/dissolution behavior.As a result,PF@Zn symmetric cells exhibit superior performance than that of bare Zn symmetric cells,achieving a stable and dendrite-free cycle of 1400 h.Furthermore,the carbon nanotube MnO2||PF@Zn （CNT/MnO2||PF@Zn） full cell also delivers a long cycle life with a high-capacity retention of about 180.0 m Ah·g-1after 1400 cycles,far exceeding that of bare Zn anode.This work provides a facile strategy for achieving a dendrite-free and rechargeable zinc anode.

关键词： Rechargeable aqueous batteries Zn metal anode Phenolic resin Anti-corrosion

Exploring Trade-offs in Thermal Interface Materials:The Impact of Polymer-Filler Interfaces on Thermal Conductivity and Thixotropy

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第7期42卷 916-925,I0006页

作者： Bin Zhang zheng-Li Dou Yong-zheng Zhang qiang Fu Kai Wu College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu610065China

Effective thermal transport across solid-solid interfaces which is essential in thermal interface materials(TIMs),necessitates both optimal thixotropy and high thermal conductivity.The role of filler surface modification,a fundamental aspect of TIM fabrication,in the influence of these properties is not fully understood.This study employs the use of a silane coupling agent(SCA)to modify alumina,integrating experimental approaches with molecular dynamics simulations,to elucidate the interface effects on thixotropy and thermal conductivity in polydimethylsiloxane(PDMS)-based TIMs.Our findings reveal that the variations of SCAs modify both interface binding energy and transition layer thickness.The interface binding energy restricts macromolecular segmental relaxation near the interface,hindering desirable thixotropy and bond line thickness.On the contrary,the thickness of the transition layer at the interface positively influences thermal conductivity,facilitating the transport of phonons between the polymer and filler.Consequently,selecting an optimal SCA allows a balance between traditionally conflicting goals of high thermal conductivity and minimal bond line thickness,achieving an impressively low interface thermal resistance of just 2.45-4.29 K·mm^(2)·W^(-1)at275.8 kPa.

关键词： Thermal interface material Surface modification Thermal conductivity Thixotropy Interface thermal resistance

Recent Advances in Asymmetric Structural Composites for Excellent Electromagnetic Interference Shielding: A Review

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第6期42卷 693-710页

作者： Ying Zhou Bai Xue Lan Xie Chang-Mei Wu qiang zheng Department of Polymer Materials and Engineering College of Materials and Metallurgy Guizhou University National Engineering Research Center for Compounding and Modification of Polymer Materials National and Local Joint Engineering Research Center for Functional Polymer Membrane Materials and Membrane Processes State Key Laboratory of Public Big Data Guizhou University Department of Polymer Science and Engineering Zhejiang University

Since electromagnetic pollution is detrimental to human health and the environment, numerous efforts have been successively made to achieve excellent electromagnetic interference shielding effectiveness(EMI SE) via designing the hierarchical structures for electromagnetic interference(EMI) shielding polymer composites. Among the plentiful structures, the asymmetric structures are currently a hot spot, principally categorizing into multi-layered, porous, fibrous, and segregated asymmetric structures, which endows the high EMI shielding performance for polymer composites incorporated with magnetic, conductive, and/or dielectric micro/nano-fillers, due to the “absorption-reflection-reabsorption” shielding mechanism. Therefore, this review provides the retrospection and summary of the efforts with respect to abundant asymmetric structures and multifunctional micro/nano-fillers for enhancing EMI shielding properties, which is conducive to the booming development of polymeric EMI shielding materials for the promising prospect in modern electronics and 5-generation(5G) technology.

关键词： Asymmetric structure Microano functional filler Polymer composite Electromagnetic interference shielding

Parallel Vision ■ Image Synthesis/Augmentation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 782-784页

作者： Wenwen Zhang Wenbo zheng qiang Li Fei-Yue Wang the School of Computer Science Shaanxi Normal UniversityXi’an 710119China the School of Computer Science and Technology Wuhan 430070China the State Key Laboratory for Management and Control of Complex Systems Institute of AutomationChinese Academy of SciencesBeijing 100190China

Dear Editor,Scene understanding is an essential task in computer vision.The ultimate objective of scene understanding is to instruct computers to understand and reason about the scenes as humans do.Parallel vision is ... 详细信息

关键词： instru explanation computer

Ectomycorrhizal fungi and dark septate endophyte inoculation improve growth and tolerance of Pinus tabulaeformis under cadmium stress

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2024年第2期34卷 473-483页

作者： Yong ZHOU yanyan zheng Pengwei LI Lingjie XU qiang FU College of Landscape Architecture and Tourism Hebei Agricultural UniversityBaoding 071000China

Forest trees can establish symbiotic associations with dark septate endophytes(DSEs)and ectomycorrhizal fungi(ECMF)simultaneously.However,the combined effects of these two fungi on the growth and cadmium(Cd)tolerance of host plants remain largely unexplored.To address this knowledge gap,a pot experiment was conducted to examine the effects of the interaction between an ECMF strain(Suillus granulatus)and a DSE strain(Pseudopyrenochaeta sp.)on Pinus tabulaeformis under Cd stress,by assessing plant growth and physiological parameters,nutrient uptake,and soil properties.Notably,the colonization rates of both fungal strains were found to increase in response to Cd stress,with the extent of this increase being influenced by the specific fungal species and the Cd level in the soil.Compared to the non-inoculation treatment,single inoculation with fungal strain resulted in enhanced biomass,root development,and nutrient contents in P.tabulaeformis seedlings under Cd stress.Furthermore,a synergistic effect was observed when these seedlings were co-inoculated with S.granulatus and Pseudopyrenochaeta sp.,as indicated by significantly greater measurements in various indicators compared to both the single and non-inoculation treatments.Fungal inoculation effectively regulated the antioxidant defense responses and photosynthesis of P.tabulaeformis seedlings subjected to Cd stress,particularly in the co-inoculation treatment.In addition,fungal inoculation facilitated the Cd accumulation in P.tabulaeformis,suggesting a promising potential for the implementation of bioremediation strategies in the areas contaminated with heavy metals.The findings from this study indicate that the utilization of root symbiotic fungi obtained from stress environments could potentially enhance the growth performance and tolerance of P.tabulaeformis towards heavy metals,and co-inoculation of both fungal groups may result in even more pronounced synergistic effects on the overall fitness of the plant.

关键词： antioxidant defense response colonization rate fungal inoculation heavy metal tolerance physiological parameter root symbiotic fungi soil property

Intermittent disturbance mechanical behavior and fractional deterioration mechanical model of rock under complex true triaxial stress paths

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2024年第1期34卷 117-136页

作者： Zhi zheng Hongyu Xu Kai Zhang Guangliang Feng qiang Zhang Yufei Zhao State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Key Laboratory of Disaster Prevention and Structural Safety of Ministry of EducationCollege of Civil Engineering and ArchitectureGuangxi UniversityNanning 530004China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing 100080China State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China

Mechanical excavation,blasting,adjacent rockburst and fracture slip that occur during mining excavation impose dynamic loads on the rock mass,leading to further fracture of damaged surrounding rock in three-dimensional high-stress and even causing disasters.Therefore,a novel complex true triaxial static-dynamic combined loading method reflecting underground excavation damage and then frequent intermittent disturbance failure is proposed.True triaxial static compression and intermittent disturbance tests are carried out on monzogabbro.The effects of intermediate principal stress and amplitude on the strength characteristics,deformation characteristics,failure characteristics,and precursors of monzogabbro are analyzed,intermediate principal stress and amplitude increase monzogabbro strength and tensile fracture mechanism.Rapid increases in microseismic parameters during rock loading can be precursors for intermittent rock disturbance.Based on the experimental result,the new damage fractional elements and method with considering crack initiation stress and crack unstable stress as initiation and acceleration condition of intermittent disturbance irreversible deformation are proposed.A novel three-dimensional disturbance fractional deterioration model considering the intermediate principal stress effect and intermittent disturbance damage effect is established,and the model predicted results align well with the experimental results.The sensitivity of stress states and model parameters is further explored,and the intermittent disturbance behaviors at different f are predicted.This study provides valuable theoretical bases for the stability analysis of deep mining engineering under dynamic loads.

关键词： True triaxial static and disturbance test Mechanical properties Failure mechanism and precursor Intermittent disturbance effect Fractional mechanical model