检索结果-南通市图书馆

Tunable quantum anomalous Hall effects in ferromagnetic van der Waals heterostructures

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

National Science Review 2024年第3期11卷 100-107页

作者： Feng Xue Yusheng Hou Zhe Wang Zhiming Xu Ke He Ruqian Wu Yong Xu Wenhui Duan Beijing Academy of Quantum Information Sciences State key laboratory of Low Dimensional Quantum physics Department of Physics Tsinghua University Guangdong Provincial key laboratory of Magnetoelectric physics and Devices Center for Neutron Science and Technology School of Physics Sun Yat-sen University State key laboratory of Surface physics Key Laboratory of Computational Physical Sciences and Department of PhysicsFudan University Frontier Science Center for Quantum Information Department of physics and Astronomy University of California-Irvine Tencent Quantum laboratory Tencent Technology(Shenzhen)Co.Ltd RIKEN Center for Emergent Matter Science(CEMS) Institute for Advanced Study Tsinghua University

The quantum anomalous Hall effect（QAHE） has unique advantages in topotronic applications, but it is still challenging to realize the QAHE with tunable magnetic and topological properties for building functional devices. Through systematic first-principles calculations, we predict that the in-plane magnetization induced QAHE with Chern numbers C = ±1 and the out-of-plane magnetization induced QAHE with high Chern numbers C = ±3 can be realized in a single material candidate, which is composed of van der Waals（vdW）coupled Bi and MnBi2Te4monolayers. The switching between different phases of QAHE can be controlled in multiple ways, such as applying strain or（weak） magnetic field or twisting the vdW materials. The prediction of an experimentally available material system hosting robust, highly tunable QAHE will stimulate great research interest in the field. Our work opens a new avenue for the realization of tunable QAHE and provides a practical material platform for the development of topological electronics.

关键词： quantum anomalous Hall effect topological quantum phase transition van der Waals heterostructures tunable Chern number high Chern number

Atomically dispersed Fe sites on hierarchically porous carbon nanoplates for oxygen reduction reaction

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy chemistry 2024年第3期90卷 7-15,I0002页

作者： Ruixue Zheng Qinglei Meng Hao Zhang Teng Li Di Yang Li Zhang Xiaolong Jia Changpeng Liu Jianbing Zhu Xiaozheng Duan Meiling Xiao Wei Xing State key laboratory of Electroanalytical chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022JilinChina School of Applied chemistry and Engineering University of Science and Technology of ChinaHefei 230026AnhuiChina laboratory of Advanced Power Sources Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022JilinChina Institute of Functional Nano&Soft Materials(FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials&DevicesJiangsu Key Laboratory of Advanced Negative Carbon TechnologiesSoochow UniversitySuzhou 215123JiangsuChina State key laboratory of Polymer physics and chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022JilinChina

Developing cost-effective,robust and stable non-precious metal catalysts for oxygen reduction reaction(ORR) is of paramount importance for electrochemical energy conversion devices such as fuel cells and metal-air *** Fe-N-C single atom catalysts(SACs) have been hailed as the most promising candidate due to the optimal binding strength of ORR intermediates on the Fe-N_(4) sites,they suffer from serious mass transport limitations as microporous templates/substrates,i.e.,zeolitic imidazolate frameworks(ZIFs),are usually employed to host the active *** by this challenge,we herein develop a hydrogen-bonded organic framework(HOF)-assisted pyrolysis strategy to construct hierarchical micro/mesoporous carbon nanoplates for the deposition of atomically dispersed Fe-N_(4) *** a design is accomplished by employing HOF nanoplates assembled from 2-aminoterephthalic acid(NH_(2)-BDC) and p-phenylenediamine(PDA) as both soft templates and C,N *** from the structural merits inherited from HOF templates,the optimized catalyst(denoted as Fe-N-C SAC-950) displays outstanding ORR activity with a high half-wave potential of 0.895 V(*** hydrogen electrode(RHE)) and a small overpotential of 356 mV at 10 mA cm^(-2) for the oxygen evolution reaction(OER).More excitingly,its application potential is further verified by delivering superb rechargeability and cycling stability with a nearly unfading charge-discharge gap of 0.72 V after 160 *** dynamics(MD) simulations reveal that micro/mesoporous structure is conducive to the rapid mass transfer of O_(2),thus enhancing the ORR *** situ Raman results further indicate that the conversion of O_(2) to~*O_(2)-the rate-determining step(RDS) for Fe-N-C *** work will provide a versatile strategy to construct single atom catalysts with desirable catalytic properties.

关键词： Fe single atom catalysts Oxygen reduction reaction Mesoporous structure Active sites Zinc-air battery

Sustainable all-weather CO2 utilization by mimicking natural photosynthesis in a single material

在线全文

学校读者我要写书评

暂无评论

National Science Review 2024年第2期11卷 177-187页

作者： Xianjin Shi Yu Huang Ran Long Zhenyu Wang Liqin Wang Junji Cao Gangqiang Zhu Yujie Xiong State key laboratory of Loess and Quaternary Geology(SKLLQG) Key Laboratory of Aerosol Chemistry and Physics Institute of Earth EnvironmentChinese Academy of Sciences Center of Excellence in Quaternary Science and Global Change Chinese Academy of Sciences University of Chinese Academy of Sciences Hefei National Research Center for Physical Sciences at the Microscale School of Chemistry and Materials Science and National Synchrotron Radiation Laboratory University of Science and Technology of China Institute of Atmospheric physics Chinese Academy of Sciences School of physics and Information Technology Shaanxi Normal University

Solar-driven CO2conversion into hydrocarbon fuels is a sustainable approach to synchronously alleviating the energy crisis and achieving net ***,the dependence of the conversion process on solar illumination hinders its practical application due to the intermittent availability of sunlight at night and on cloudy or rainy ***,we report a model material of Pt-loaded hexagonal tungsten trioxide（Pt/h-WO3） for decoupling light and dark reaction processes,demonstrating the sustainable CO2conversion under dark conditions for the first *** such a material system,hydrogen atoms can be produced by photocatalytic water splitting under solar illumination,stored together with electrons in the h-WO3through the transition of W6+to W5+and spontaneously released to trigger catalytic CO2reduction under dark ***,we demonstrate using natural light that CH4production can persist at night and on rainy days,proving the accomplishment of all-weather CO2conversion via a sustainable way.

关键词： sustainable CO2 utilization artificial photosynthesis all-weather application charge storage

Tunable energy spectrum betatron x-ray sources in a plasma wakefield

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 physics B 2024年第8期33卷 344-350页

作者：奚传易寿寅任韩立琦阿卜杜伍普尔·阿布力米提刘晓丹赵研英余金清 Hunan Provincial key laboratory of High-Energy Scale physics and Applications School of Physics and ElectronicsHunan UniversityChangsha 410082China Center for Relativistic Laser Science Institute for Basic ScienceGwangjuKorea State key laboratory of Nuclear physics and Technology and Key Laboratory of HEDP of the Ministry of EducationCAPTPeking UniversityBeijing 100871China

X-ray sources with tunable energy spectra have a wide range of applications in different scenarios due to their different penetration ***,existing x-ray sources face difficulties in terms of energy *** this paper,we present a scheme for tuning the energy spectrum of a betatron x-ray generated from a relativistic electron bunch oscillating in a plasma *** center energy of the x-ray source can be tuned from several keV to several hundred keV by changing the plasma density,thereby extending the control range by an order of *** different central energies,the brightness of the betatron radiation is in the range of 3.7×10^(22)to 5.5×10^(22)photons/(0.1%BW·s·mm^(2)·mrad^(2))and the photon divergence angle is about 2 *** high-brightness,energy-controlled betatron source could pave the way to a wide range of applications requiring photons of specific energy,such as phase-contrast imaging in medicine,non-destructive testing and material analysis in industry,and imaging in nuclear physics.

关键词： betatron plasma physics x-ray plasma wakefield acceleration(PWFA)

Iron-based layered double hydroxide packed with metal-organic frameworks for enhanced overall water-splitting electrocatalysis

在线全文

学校读者我要写书评

暂无评论

Tungsten 2024年第4期6卷 859-868页

作者： Long Chen Yun Luo Zhi-Peng Yu Yi-Kun Cheng Yang Zheng Li He Jia-Hao Xiong Wen-Wen Kong key laboratory for Green Process of Chemical Engineering of Xinjiang Bingtuan School of Chemistry and Chemical Engineering Shihezi University Institute of Scientific Research Luzhou North Chemistry Industry Co.Ltd International Iberian Nanotechnology laboratory (INL) CAS key laboratory of Functional Materials and Devices for Special Environments Xinjiang Key Laboratory of Electronic Information Materials and Devices Center of Materials Science and Optoelectronics Engineering Xinjiang Technical Institute of Physics and Chemistry of CAS

Designing hybrid materials with numerous catalytic active sites,high specific surface area,and interfacial interactions is an effective strategy to improve electrocatalytic *** this work,iron-based metal organic frameworks（Fe-MOFs）@（Co,Ni）Fe-layered double hydroxide（LDH） is successfully constructed using the similar "MOF growing on LDH" strategy for oxygen evolution reaction and hydrogen evolution reaction in the alkaline *** synthesized hybrid materials in this particular way show excellent electrochemical overall water-splitting performance with the cell voltage of 1.62 V at10 mA·cm-2in the alkaline environment due to the optimized adsorption/desorption properties of metal ions on oxygencontaining species and interfacial effects of hybrid ***-MOFs@（Co,Ni）Fe-LDH also exhibits excellent hydrogen and oxygen production efficiency of 370 and 175 μL·min-1,*** work draws on an effective approach to the fabrication of MOF@LDH structures and provides new insights into overall water-splitting in alkaline conditions.

关键词： Electrocatalysis Interfacial interactions Layered double hydroxide Metal–organic frameworks (MOFs) Water splitting

High-pressure study on calcium azide(Ca(N_(3))_(2)):Bending of azide ions stabilizes the structure

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 physics B 2024年第5期33卷 542-548页

作者：武晓鑫王颖健李思琪吕俊呈王婧姝杨丽华张旗刘艳清张俊凯贾洪声 key laboratory of Functional Materials physics and chemistry (Ministry of Education) College of PhysicsJilin Normal UniversityChangchun 130103China The Joint laboratory of MXene Materials Jilin Normal University & Jilin 11 Technology Co.Ltd.Changchun 130103China

The high-pressure structure and elastic properties of calcium azide(Ca(N_(3))_(2))were investigated using in-situ highpressure x-ray diffraction and Raman scattering up to 54 GPa and 19 GPa,*** compressibility of Ca(N_(3))_(2)changed as the pressure increased,and no phase transition occurred within the pressure from ambient pressure up to 54 *** measured zero-pressure bulk modulus of Ca(N_(3))_(2)is higher than that of other alkali metal azides,due to differences in the ionic character of their metal-azide *** CASTEP,all vibration modes of Ca(N_(3))_(2)were accurately identified in the vibrational spectrum at ambient *** the high-pressure vibration study,several external modes(ext.)and internal bending modes(ν_(2))of azide anions(N_(3)^(-))softened up to~7 GPa and then hardened beyond that *** evidence is consistent with the variation observed in the F_(E)–f_(E)data analyzed from the XRD result,where the slope of the curve changes at 7.1 *** main behaviors under pressure are the alternating compression,rotation,and bending of N_(3)^(-)*** bending behavior makes the structure of Ca(N_(3))_(2)more stable under pressure.

关键词： high pressure calcium azide azide anions

Ligand-controlled NiH-catalyzed regiodivergent hydroalkylation of 2-alkenylazaarenes

在线全文

学校读者我要写书评

暂无评论

Science China chemistry 2024年第6期67卷 1935-1940页

作者： Ya-Ping Shao Zhuo-Min Chi Yong-Min Liang State key laboratory of Applied Organic chemistry School of Chemistry and Chemical EngineeringLanzhou UniversityLanzhou730000China

A nickel-hydride(Ni H)-catalyzed migratory and nonmigratory hydroalkylation reaction of 2-alkenyl azaarenes with alkyl iodines has been established through strategic modulation of N-or P-donor *** method enables the synthesis of diverseβ-orγ-branched aromatic *** mild regiodivergent protocols exhibit wide substrate scope,excellent functional tolerance,and great reaction yield with remarkable ***,deuterium labeling studies reveal Ni H-catalyzed interrupted chain-walking mode as the mechanism behind remotedβ-selective hydroalkylation reaction—an interesting phenomenon mediated through aromatic imine directing groups.

关键词： NiH regiodivergent hydroalkylation azaarenes interrupted chain-walking

Liquid-mediated Ostwald ripening of Ag-based clusters supported on oxides

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第6期17卷 4971-4978页

作者： Conghui Liu Rongtan Li Yamei Fan Shiwen Li Xiaohui Feng Lu Feng Yanxiao Ning Qiang Fu School of chemistry Dalian University of TechnologyDalian 116024China State key laboratory of Catalysis Chinese Academy of SciencesDalian Institute of Chemical PhysicsDalian 116023China

Reconstruction of supported nanocatalysts often occurs in gas-solid reactions and significantly affects the catalytic performance,yet it is much less explored in liquid-phase ***,we find that highly-dispersed Ag nanocatalysts,i.e.,AgOx clusters,supported on alumina,silica,and titania,can aggregate into larger Ag or Ag2O particles after immersing in liquid-phase media at room *** spontaneous aggregation of AgOx clusters in liquid water is attributed to liquid-phase Ostwald ripening through dissolution of AgOx clusters into water and subsequent redeposition to form Ag2O *** immersion into organic solvents such as ethanol leads to reduction of AgOx clusters and further growth into Ag *** work reveals that liquid-phase reaction media can induce substantial structural evolution of supported nanostructured catalysts,which should be carefully considered in liquid-solid interface catalytic reactions such as electrocatalysis,environmental catalysis,and organic synthesis in liquid phase.

关键词： Ag catalysts Ostwald ripening liquid phase media dissolution-deposition process

Thermal Performance of a 4 K High-Frequency Pulse Tube Cryocooler with Different Working Fluids

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Thermal Science 2024年第4期33卷 1468-1479页

作者： GAO Zhaozhao YANG Biao FAN Xiaoyu CHEN Liubiao WANG Junjie key laboratory of Cryogenic Science and Technology Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China

The high-frequency pulse tube cryocooler(HPTC)represents a promising miniature cryocooling technology due to its compact structure and the absence of low-temperature moving ***,limited to the non-ideal gas effect of4He,the HPTC is hard to obtain high cooling performance in the liquid helium temperature range.3He as the working fluid can effectively improve the cooling performance of the HPTC,but the high cost hinders its wide *** consideration of both cooling performance and cost-effectiveness,this paper explores the feasibility of utilizing^(3)He-^(4)He mixtures as the working fluid for ***,the experimental results of a developed HPTC based4He are *** a total power consumption of 575 W,the lowest temperature of 3.26 K was *** the measured cooling power at 4.2 K was 20.8 *** the theoretical utmost efficiency of the cryocooler was calculated in terms of the thermophysical properties of the working fluids,using ^(3)He-^(4)He mixtures with different compositions as the working *** whole machine modeling of the HPTC was further carried out,and the influence of the working fluids with different components on the structural parameters such as double-inlet and inertance tube,and operating parameters such as pressure and frequency were *** calculated results show that the cooling power is expected to be increased to36 mW and 53 mW if the equimolar ^(3)He-^(4)He mixture and pure ^(3)He are used,respectively.

关键词： high-frequency pulse tube cryocooler ^(3)He-^(4)He mixture liquid helium temperature thermally coupled