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Quasi-two-dimensional strong liquid-like dynamics of surface atoms in metallic glasses

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Science China(Physics,Mechanics & Astronomy) 2024年第3期67卷 102-109页

作者： Bing Wang Xuanqiao gao Rui Su Pengfei guan School of Physical Science and Technology Northwestern Polytechnical UniversityXi'an 710072China Innovation Center NPU Chongqing Northwestern Polytechnical UniversityChongqing 401135China School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710072China Northwest Institute for Nonferrous Metal Research Xi'an 710016China Institute of Advanced Magnetic Materials College of Materials and Environmental EngineeringHangzhou Dianzi University Hangzhou 310018China Beijing Computational Science Research Center Beijing 100093China

The fast dynamic properties of the surface of metallic glasses(MGs) play a critical role in determining their potential applications. However, due to the significant difference in thermal history between atomic simulation models and laboratory-made samples, the atomic-scale behaviors of the fast surface dynamics of MGs in experiments remain uncertain. Herein, we prepared model MG films with notable variations in thermal stability using a recently developed efficient annealing protocol, and investigated their atomic-scale dynamics systematically. We found that the dynamics of surface atoms remain invariant, whereas the difference in dynamical heterogeneity between surface and interior regions increases with the improvement of thermal stability. This can be associated with the more pronounced correlation between atomic activation energy spectra and depth from the surface in samples with higher thermal stability. In addition, dynamic anisotropy appears for surface atoms, and their transverse dynamics are faster than normal components, which can also be interpreted by activation energy spectra. Our results reveal the presence of strong liquid-like atomic dynamics confined to the surface of laboratory-made MGs, illuminating the underlying mechanisms for surface engineering design, such as cold joining by ultrasonic vibrations and superlattice growth.

关键词： metallic glasses thermal stability invariant surface dynamics potential energy landscape dynamic anisotropy and heterogeneity

Electrolyte effect on electrochemical behaviors of manganese fluoride material for aqueous asymmetric and symmetric supercapacitors

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Rare Metals 2024年第3期43卷 1048-1061页

作者： Zheng-hua He Jian-Fei gao Ling-Bin Kong State Key Laboratory of Advanced Processing and Recycling of Non-Ferrous Metals Lanzhou University of TechnologyLanzhou730050China School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou730050China

Exploring wide voltage window materials is not only an available measure to enhance the energy density of hybrid supercapacitor(HSCs),but also avoids the dynamic mismatch caused by different energy storage mechanisms of two electrodes in assembled symmetrical ***,there are few reports about the wide potential window materials except Bi_(2)O_(3)and VO_(2).Therefore,the MnF_(2)synthesized by solvothermal reaction was served as the electrode for *** MnF_(2)exhibited electrochemical activity in alkaline solution in three-electrode system,especially with a wide potential window from-0.8 to+0.5 V in 2 mol·L^(-1)***,the assembled MnF_(2)//MnF_(2)symmetrical HSC had a potential window of 1.5 V,and it exhibited outstanding long-cycle ***,when MnF_(2)was taken as the negative and positive respectively,the potential windows of asymmetric devices CoMoO_(4)//MnF_(2)and MnF_(2)//Activated Carbon(AC)could reach 1.3 and 1.45 V,respectively,showing excellent cycle *** work shows that MnF_(2)material has great research value in HSC,and provides a new research direction for developing high-performance devices.

关键词： Manganese fluoride Potential window Hybrid supercapacitors Electrochemical performance

Maximum Principle for Stochastic Control System with Elephant Memory and Jump Diffusion

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Journal of Systems Science & Complexity 2024年第4期37卷 1392-1412页

作者： FENG Siqi gao Lei WANG guangchen XIAO hua School of Control Science and Engineering Shandong UniversityJinan 250061China School of Economics Shandong UniversityJinan 250100China School of Mathematics and Statistics Shandong UniversityWeihai 264209China

Motivated by a duopoly game problem,the authors study an optimal control problem where the system is driven by Brownian motion and Poisson point process and has elephant memory for the control variable and the state ***,the authors establish the unique solvability of an anticipated backward stochastic differential equation,derive a stochastic maximum principle,and prove a verification theorem for the aforementioned optimal control ***,the authors generalize these results to nonzero-sum stochastic differential game ***,the authors apply the theoretical results to the duopoly game problem and obtain the corresponding Nash equilibrium solution.

关键词： Anticipated backward stochastic differential equation elephant memory Fréchet derivative maximum principle stochastic delayed differential equation

Different El Niño Flavors and Associated Atmospheric Teleconnections as Simulated in a Hybrid Coupled Model

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Advances in Atmospheric Sciences 2024年第5期41卷 864-880页

作者： Junya HU Hongna WANG Chuan gao Rong-hua ZHANG Key Laboratory of Ocean Circulation and Waves Institute of Oceanologyand Center for Ocean Mega-ScienceChinese Academy of SciencesQingdao 266071China School of Marine Sciences Nanjing University of Information Science and TechnologyNanjing 210044China Laoshan Laboratory Qingdao 266237China

A previously developed hybrid coupled model(HCM)is composed of an intermediate tropical Pacific Ocean model and a global atmospheric general circulation model(AGCM),denoted as *** this study,different El Niño flavors,namely the Eastern-Pacific(EP)and Central-Pacific(CP)types,and the associated global atmospheric teleconnections are examined in a 1000-yr control simulation of the *** HCMAGCM indicates profoundly different characteristics among EP and CP El Niño events in terms of related oceanic and atmospheric variables in the tropical Pacific,including the amplitude and spatial patterns of sea surface temperature(SST),zonal wind stress,and precipitation *** SST budget analysis indicates that the thermocline feedback and zonal advective feedback dominantly contribute to the growth of EP and CP El Niño events,*** to the shifts in the tropical rainfall and deep convection during EP and CP El Niño events,the model also reproduces the differences in the extratropical atmospheric responses during the boreal *** particular,the EP El Niño tends to be dominant in exciting a poleward wave train pattern to the Northern Hemisphere,while the CP El Niño tends to preferably produce a wave train similar to the Pacific North American(PNA)*** a result,different climatic impacts exist in North American regions,with a warm-north and cold-south pattern during an EP El Niño and a warm-northeast and cold-southwest pattern during a CP El Niño,*** modeling result highlights the importance of internal natural processes within the tropical Pacific as they relate to the genesis of ENSO diversity because the active ocean–atmosphere coupling is allowed only in the tropical Pacific within the framework of the HCMAGCM.

关键词： hybrid coupled model tropical Pacific Ocean global atmosphere Eastern/Central-Pacific El Niño atmospheric teleconnections

Exploration of cardiac rehabilitation nursing for elderly patients with myocardial infarction based on individualized cardiac rehabilitation

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World Journal of Clinical Cases 2024年第2期12卷 256-266页

作者： hua-Ning Liu Bo gao Department of Geriatrics General Hospital of the YangTze River ShippingWuhan Brain HospitalWuhan 430015Hubei ProvinceChina Department of Cardiology Suizhou Central HospitalAffiliated Hospital of Hubei University of MedicineSuizhou 441300Hubei ProvinceChina

BACKGROUND Myocardial infarction is a high-risk condition prevalent among the elderly population,often leading to adverse clinical manifestations such as reduced cardiopulmonary function,anxiety,and depression ***,cardiac rehabilitation holds immense importance in mitigating these *** To evaluate the effect of individualized cardiac rehabilitation on blood pressure variability(BPV)and baroreflex sensitivity(BRS)in elderly patients with myocardial *** A cohort of 74 elderly patients diagnosed with myocardial infarction and admitted to our hospital between January 2021 and January 2022 were subjected to random ***,all patients were divided into two groups,namely the research group(n=37)and the control group(n=37),utilizing the number table *** control group received conventional drug treatment and nursing guidance intervention,while the study group underwent individualized cardiac rehabilitation in addition to the interventions received by the control *** patients were continuously intervened for 12 wk,and the BPV of these two groups in the 1st wk(T0),the 4th wk(T1)and the 12th wk(T2)were compared,BRS,changes in cardiopulmonary function measures,and adverse cardiovascular *** Of 24 h diastolic BPV,24 h systolic BPV,carbon dioxide ventilation equivalent slope of the research group were lower than those of the control group at T1 and T2,BRS,peak heart rate and systolic blood pressure product,1 min heart rate recovery were higher than those of the control group,and the incidence of adverse events in the research group was lower than that of the control group,the difference was statistically significant(P<0.05).CONCLUSION In this study,we found that after individualized cardiac rehabilitation in elderly patients with myocardial infarction,BPV and BRS can be effectively improved,cardiac function is significantly enhanced,and a better prognosis is obtained.

关键词： Individualized cardiac rehabilitation Myocardial infarction Variability in blood pressure Baroreflex sensitivity

Three-dimensional porous In_(2)O_(3) arrays for self-powered transparent solar-blind photodetectors with high responsivity and excellent spectral selectivity

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Nano Research 2024年第5期17卷 4471-4477页

作者： Nana Zhang Xinyu gao Haoran guan Simin Sun Jiaming Liu Zhitao Shao Qiyue gao Yuan Zhang Ruyu Sun guang Yang Feng gao Wei Feng College of Chemistry Chemical Engineering and Resource UtilizationNortheast Forestry UniversityHarbin 150040China Key Laboratory for Photonic and Electronic Bandgap Materials Ministry of EducationSchool of Physics and Electronic EngineeringHarbin Normal UniversityHarbin 150025China

Transparent solar-blind ultraviolet photodetectors(SBUV PDs)have extensive applications in versatile scenarios,such as optical ***,it is still challenging to simultaneously achieve high responsivity,high transparency,and satisfying self-powered ***,we demonstrated high-performance,transparent,and self-powered photoelectrochemical-type(PEC)SBUV PDs based on vertically grown ultrathin In_(2)O_(3) nanosheet arrays(NAs)with a three-dimensional(3D)porous *** 3D porous structure simultaneously improves the transmittance in the visible light region,accelerates interfacial reaction kinetics,and promotes photogenerated carrier *** performance of In_(2)O_(3) NAs photoanodes exceeds most reported self-powered PEC SBUV PDs,exhibiting a high transmittance of approximately 80%in the visible light region,a high responsivity of 86.15 mA/W for 254 nm light irradiation,a fast response speed of 15/18 ms,and good multicycle *** In_(2)O_(3) NAs also show excellent spectral selectivity with an ultrahigh solar-blind rejection ratio of 1319.30,attributed to the quantum confinement effect induced by the ultrathin feature(2-3 nm).Furthermore,In_(2)O_(3) NAs photoanodes show good capability in underwater optical *** work demonstrated that a 3D porous structure is a powerful strategy to synchronously achieve high responsivity and transparency and provides a new perspective for designing high-performance,transparent,and self-powered PEC SBUV PDs.

关键词： In_(2)O_(3) three-dimensional porous transparent photoelectrochemical solar-blind photodetectors

Impact of Local Climate Zones on the Urban Heat and Dry Islands in Beijing:Spatial Heterogeneity and Relative Contributions

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Journal of Meteorological Research 2024年第1期38卷 126-137页

作者： Zuofang ZHENG Fu LUO Nana LI hua gao Yuanjian YANG Institute of Urban Meteorology China Meteorological AdministrationBeijing 100089 School of Atmospheric Physics Nanjing University of Information Science&TechnologyNanjing 210044 Key Laboratory of Urban Meteorology China Meteorological AdministrationBeijing 100089

Based on the building height and density data on a 100-m resolution,hourly 2-m temperature and humidity data at83 automatic weather stations,and gridded local climate zone(LCZ)data on a 120-m resolution in urban Beijing in2020,this study first employs the semivariogram combined with building parameters to calculate spatial correlations and has identified an LCZ grid resolution of 500 m suitable for best usage of the available observation ***,how the spatially heterogeneous LCZs affect and contribute to the canopy urban heat island intensity(UHII)and urban dry island intensity(UDII)are quantitatively *** is found that UHII is high in winter and low in summer with a unimodal diurnal variation while UDI is low in winter but high in summer with a bimodal diurnal *** LCZ with compact mid-rise(open high-rise)buildings exhibits the highest UHII(UDII),followed by the compact high-rise(compact low-rise),while the LCZ of scattered trees presents both the lowest UHII and the lowest *** most significant difference in the UHII(UDII)among the nine LCZ types in the urban area of Beijing is2.62℃(1.1 g kg^(-1)).Area-weighted averaging analysis reveals that the open mid-rise LCZ is the most significant contributor to the UHII(UDII),immediately followed by compact mid-rise(open low-rise),with the least contribution from bare rock or paved(scattered trees).The results also indicate that beyond the intrinsic physical properties of the LCZs of a city,their area proportions cannot be overlooked in evaluating their impact on the UHI and *** quantitatively findings could help urban planners to create a livable urban climate and environment by adjusting the relevant land use.

关键词： local climate zone(LCZ) urban heat island(UHI) urban dry island(UDI) distribution pattern contribution rate Beijing

Effect of Microstructural Characteristics on Fracture Toughness in Direct Energy Deposited Novel Ti-6Al-4V-1Mo Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 119-131页

作者： Chao Xia Kexin Zhao Xin Zhou Yuqi He Panpan gao Hengxin Zhang guangrui gao Fengying Zhang hua Tan School of Material Science and Engineering Chang’an UniversityXi’an710064China Science and Technology on Plasma Dynamics Laboratory Air Force Engineering UniversityXi’an710038China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an710072China Surface Material Protection Co. LtdXi’an710018China

Meeting the damage tolerance requirements for engineering-grade titanium alloys pose a significant challenge in achieving high fracture toughness in direct energy deposition(DED)titanium *** work primarily investigated the relationship between the microstructure and the fracture toughness of DED new Ti-6Al-4V-1Mo *** types of microstructures were designed via two process strategies:high-line energy density(HE)and low-line energy density(LE).Relative to LE samples,HE samples possess larger-sized microstructural characteristics(coarser grain boundaryα(α_(GB)),largerαcolonies,and coarserαlaths).Lessα/βphase boundaries were formed by coarserαlaths in the HE samples,increasing the movement of dislocations,resulting in tensile strength decreasing from 1007.1 MPa(LE)to 930.8 MPa(HE)and elongation increasing from 10.8%(LE)to 15.7%(HE).Also,HE samples exhibited an excellent fracture toughness of 114.0 MPa m^(1/2),significantly higher than that of LE samples(76.8 MPa m^(1/2)).An analysis of crack propagation paths was conducted to investigate the factors contributing to *** primary factor enhancing toughness is the frequent obstruction of cracks by coarseαGB and largeαcolonies in HE ***,the pretty large-angle deflections induced by the superposition effect of coarseαGB and largeαcolonies play a vital of significant *** factors induced the long and tortuous high-energy pathways,which resulted in ultimately improved fracture *** discovered microstructural toughening mechanisms can serve as a reference for future studies involving titanium alloys,offering insights on how to enhance fracture toughness by achieving similar characteristics.

关键词： Direct energy deposition Ti-6Al-4V-1Mo Tensile properties Fracture toughness Crack propagation

Fabrication of amorphous FeCoNiCuMnP x high-entropy phosphide/carbon composites with a heterostructured fusiform morphology for efficient oxygen evolution reaction

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Journal of Materials Science & Technology 2024年第1期168卷 62-70页

作者： Yifan Zhou Longqing gao Haoyuan Chen Hao Wang Juan Zhang Xiumin Li Fangfang Duo Guoqing guan School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China Graduate School of Sustainable Community Studies Hirosaki University1-BunkyochoHirosaki 036-8560Japan Graduate School of Science and Technology Hirosaki University3-BunkyochoHirosaki 036-8561Japan Xinxiang University School of Chemistry&Materials EngineeringXinxiang 453003China Energy Conversion Engineering Laboratory Institute of Regional InnovationHirosaki University3-BunkyochoHirosaki 036-8561Japan

Amorphous high-entropy materials with abundant defects,coordinatively unsaturated sites,and loosely bonded atoms could exhibit excellent electrocatalytic ***,how to fabricate such ma-terials with nanostructure as well as amorphous structure is still full of *** this work,high-entropy metal organic framework(HE-MOF)is employed as the self-sacrificial template to fabricate FeCoNiCuMnP x high-entropy phosphide/carbon(HEP/C)*** obtained composite shows a het-erostructured fusiform morphology,in which the HEP is encapsulated by a carbon layer,revealing high electron conductivity as well as rich catalytic active sites for oxygen evolution reaction(OER).Beside,it is found that there is a short-range ordered crystal structure in the amorphous phase,which is bene-ficial for revealing high OER catalytic activity as well as good *** a result,the optimum HEP/C composite shows an overpotential 239 mV@10 mA cm^(−2)with a small Tafel slope of 72.5 mV dec^(−1) for catalyzing OER in alkaline solution.

关键词： Water electrolysis Oxygen evolution reaction High-entropy MOFs High-entropy phosphides Amorphous structure