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Strengthening mechanisms analysis and tailoring of bimodal grain structures for enhanced strength in CoCrFeMnNi high-entropy alloys

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Rare Metals 2024年第8期43卷 3893-3903页

作者： Jaesoung lee Seulgi Kim Taehyun Kwon Young II Kim Suyeon Kim Sung Ho Song Bin lee Dongju lee Department of Urban Energyand Environmental EngineeringChungbuk National UniversityCheongju 28644Republic of Korea Division of Advanced Materials Engineering Kongju National UniversityChungnam 330-717Republic of Korea Department of Advanced Materials Engineering for Information and Electronics Integrated-Education Institute for Frontier Science and Technology(BK21 Four)Kyung Hee UniversityYongin17104Republic of Korea

The CoCrFeMnNi high-entropy alloys(HEAs)with a(face-centered cubic) FCC structure has garnered considerable attention for its exceptional ductility and strain hardening ***,its yield strength is insufficient for structural *** this study,strengthening mechanisms in these HEAs were investigated to gain insight into the mechanical properties according to alloy powder ***,we present a novel approach to achieve both high strength and high ductility through the creation of a bimodal structure consisting of both coarse and fine grains via gas atomization and spark plasma sintering processes.A bimodally structured HEA prepared with a mass ratio of 2:8 between coarse particles(75-106 μm) and fine particles(≤25 μm)yielded optimal results,with a strength of 491.95 MPa and elongation of 19.64%.This strength value represents an~41% increase compared with the sample that displayed a fine single microstructure(347.08 MPa for yield strength).The strength enhancement was attributed to the prevention of plastic deformation initiation from the fine particles during *** innovative approach to the creation of HEAs with bimodal structures shows promise for various applications,such as structural components that require a combination of high strength and high ductility.

关键词： High-entropy alloys CrCoFeMoNi Bimodal Gas atomization Mechanical properties

Variability and trends of near-surface wind speed over the Tibetan Plateau:The role played by the westerly and Asian monsoon

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Advances in Climate Change Research 2024年第3期15卷 525-536页

作者： Gang-feng ZHANG Cesar AZORIN-MOLINA Deliang CHEN Tim RMCVICAR Jose AGUIJARRO Kai-Qiang DENG Lorenzo MINOLA Jaeyeon lee Seok-Woo SON Heng MA Pei-Jun SHI State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing 100875China Engineering Center of Desertification and Blown-Sand Control of Ministry of Education Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China Key Laboratory of Environmental Change and Natural Disaster of Ministry of Education Beijing Normal UniversityBeijing 100875China Centro de Investigaciones Sobre Desertificaci'on Consejo Superior de Investigaciones Cientı'ficas(CIDECSIC-UV-Generalitat alenciana)ClimateAtmosphere and Ocean Laboratory(Climatoc-Lab)Moncada 46113Spain Regional Climate Group Department of Earth SciencesUniversity of GothenburgGothenburg 40530Sweden CSIRO Environment CanberraACT 2600Australia Australian Research Council Centre of Excellence for Climate Extremes CanberraACT 2600Australia State Meteorological Agency Balearic Islands OfficePalma de Mallorca 07015Spain School of Atmospheric Sciences Sun Yat-sen UniversityZhuhai 519082China Interuniversity Department of Regional and Urban Studies and Planning(DIST) Politecnico and University of TurinTurin 10125Italy School of Earth and Environmental Sciences Seoul National UniversitySeoul 08826South Korea Atmospheric and Oceanic Sciences Program Princeton UniversityPrinceton NJ 08544USA Geophysical Fluid Dynamics Laboratory NOAAPrinceton NJ 08544USA

Near-surface wind speed exerts profound impacts on many environmental issues,while the long-term(≥60 years)trend and multidecadal variability in the wind speed and its underlying causes in global high-elevation and mountainous areas(e.g.,Tibetan Plateau)remain largely ***,by examining homogenized wind speed data from 104 meteorological stations over the Tibetan Plateau for 1961-2020 and ERA5 reanalysis datasets,we investigated the variability and long-term trend in the near-surface wind speed and revealed the role played by the westerly and Asian *** results show that the homogenized annual wind speed displays a decreasing trend(-0.091 m s^(−1)per decade,p<0.05),with the strongest in spring(-0.131 m s^(−1)per decade,p<0.05),and the weakest in autumn(-0.071 m s^(−1)per decade,p<0.05).There is a distinct multidecadal variability of wind speed,which manifested in an prominent increase in 1961-1970,a sustained decrease in 1970-2002,and a consistent increase in *** observed decadal variations are likely linked to large-scale atmospheric circulation,and the correlation analysis unveiled a more important role of westerly and East Asian winter monsoon in modulating near-surface wind changes over the Tibetan *** potential physical processes associated with westerly and Asian monsoon changes are in concordance with wind speed change,in terms of overall weakened horizontal air flow(i.e.,geostrophic wind speed),declined vertical thermal and dynamic momentum transfer(i.e.,atmospheric stratification thermal instability and vertical wind shear),and varied Tibetan Plateau *** indicates that to varying degrees these processes may have contributed to the changes in near-surface wind speed over the Tibetan *** study has implications for wind power production and soil wind erosion prevention in the Tibetan Plateau.

关键词： Tibetan Plateau Wind speed Decadal change Atmospheric circulation Physical processes

Optimal transcorneal electrical stimulation parameters for preserving photoreceptors in a mouse model of retinitis pigmentosa

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Neural Regeneration Research 2024年第11期19卷 2543-2552页

作者： Sam Enayati Karen Chang Anton Lennikov Menglu Yang Cherin lee Ajay Ashok Farris Elzaridi Christina Yen Kasim Gunes Jia Xie Kin-Sang Cho Tor Paaske Utheim Dong feng Chen Schepens Eye Research Institute of Massachusetts Eye and Ear Department of OphthalmologyHarvard Medical SchoolBostonMAUSA Institute of clinical medicine Faculty of MedicineUniversity of OsloOsloNorway Department of Medical Biochemistry Oslo University HospitalUniversity of OsloOsloNorway Department of Ophthalmology Drammen HospitalVestre Viken Hospital TrustDrammenNorway Department of Histology and Embryology School of MedicineMarmara UniversityIstanbulTurkiye

Retinitis pigmentosa is a hereditary retinal disease that affects rod and cone photoreceptors,leading to progressive photoreceptor *** research supports the beneficial effect of electrical stimulation on photoreceptor *** study aims to identify the most effective electrical stimulation parameters and functional advantages of transcorneal electrical stimulation(tcES)in mice affected by inherited retinal ***,the study seeked to analyze the electric field that reaches the retina in both eyes in mice and post-mortem *** this study,we recorded waveforms and voltages directed to the retina during transcorneal electrical stimulation in C57BL/6J mice using an intraocular needle probe with rectangular,sine,and ramp *** investigate the functional effects of electrical stimulation on photoreceptors,we used human retinal explant cultures and rhodopsin knockout(Rho^(-/-))mice,demonstrating progressive photoreceptor degeneration with *** retinal explants isolated from the donors’eyes were then subjected to electrical stimulation and cultured for 48 hours to simulate the neurodegenerative environment in *** density was evaluated by rhodopsin *** vivo Rho^(-/-)mice were subjected to two 5-day series of daily transcorneal electrical stimulation using rectangular and ramp *** function and visual perception of mice were evaluated by electroretinography and optomotor response(OMR),*** was used to assess the morphological and biochemical changes of the photoreceptor and bipolar cells in mouse *** recordings indicated effective delivery of rectangular,sine,and ramp waveforms to the retina by transcorneal electrical stimulation,of which the ramp waveform required the lowest *** of the total conductive resistance of the post-mortem human compared to the mouse eyes indicated higher cornea-to-retina resistance in human *** tem

关键词： bipolar cells electrical stimulation neuroprotection photoreceptor degeneration retina retinal explants retinitis pigmentosa transcorneal electrical stimulation waveform

Research on Cavitation Characteristics and Influencing Factors of Herringbone Gear Pump

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Computer Modeling in Engineering & Sciences 2024年第6期139卷 2917-2946页

作者： Jinlong Yang Kwang-Hee lee Chul-Hee lee Department of Mechanical Engineering of Inha University Incheon22212South Korea

Cavitation is a common issue in pumps,causing a decrease in pump head,a fall in volumetric efficiency,and an intensification of outlet flow *** is one of the main hazards that affect the regular operation of the *** on pump cavitation mainly focuses on mixed flow pumps,jet pumps,external spur gear pumps,***,there are few cavitation studies on external herringbone gear *** addition,pumps with different working principles significantly differ in the flow and complexity of the internal flow ***,it is urgent to study the cavitation characteristics of external herringbone gear *** with experimentalmethods,visual research and cavitation area identification are achieved through computation fluid dynamic(CFD),and changing the boundary conditions and shape of the gear rotor is *** simulation yields a head error of only 0.003%under different grid numbers,and the deviation between experimental and simulation results is less than 5%.The study revealed that cavitation causes flow pulsation at the outlet,and the cavitation serious area is mainly distributed in the meshing gap and meshing *** can be inhibited by reducing the speed,increasing the inlet pressure,and changing the helix angle can be *** example,when the inlet pressure is 5 bar,the maximumgas volume fraction in themeshing area is less than 50%.These results provide a reference for optimizing the design and finding the optimal design parameters to reduce or eliminate cavitation.

关键词： Herringbone gear pump cavitation rotating speed inlet pressure helix angle TwinMesh

Revealing the influence of in-situ formed LiCl on garnet/Li interface for dendrite-free solid-state batteries

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Journal of Energy Chemistry 2024年第5期92卷 394-403页

作者： Seoyoon Shin Jinuk lee Tae Ho Shin Seokhee lee Hydrogen Energy Materials Center Korea Institute of Ceramic Engineering&TechnologyJinju-siGyeongsangnam-do 52851Republic of Korea Department of Materials Science and Engineering Yonsei UniversitySeoul 03722Republic of Korea

Inadequate interfacial contact between lithium and solid-state electrolytes(SSEs)leads to elevated impedance and the growth of lithium dendrites,presenting significant obstacles to the practical viability of solid-state batteries(SSBs).To ameliorate interfacial contact,optimizing the surface treatment of SSEs has been widely ***,the formation of LiCl through acid treatment,an equally crucial factor impacting SSB performance,has received limited attention,leaving its underlying mechanism *** study aims to shed light on SSE characteristics following LiCl formation and the removal of Li_(2)CO_(3) through acid *** seek to establish quantifiable links between SSE surface structure and SSB performance,focusing on interfacial resistance,current distribution,critical current density(CCD),and lithium *** formation of LiCl,occurring as Li_(2)CO_(3) is removed through acid treatment,effectively mitigates lithium dendrite formation on SSE *** action inhibits electron injection and reduces the diffusion rate of Li ***,acid treatment transforms the SSE surface into a lithiophilic state by eliminating surface Li_(2)CO_(3).Consequently,the interfacial resistance between lithium and SSEs substantially decreases from 487.67 to 35.99Ωcm^(2) at 25°*** leads to a notably high CCD of 1.3 mA cm^(-2) and a significantly extended cycle life of 1,000 ***,in full SSBs incorporating LiCoO_(2)cathodes and acid-treated garnet SSEs,we observe exceptional cyclability and rate *** findings highlight that acid treatment not only establishes a fundamental relationship between SSE surfaces and battery performance but also offers an effective strategy for addressing interfacial challenges in SSBs.

关键词： Solid-statebatteries Acidtreatment Interfacial stability LiCl Surface modification

Development of vehicle-recognition method on water surfaces using LiDAR data:SPD^(2)(spherically stratified point projection with diameter and distance)

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Defence Technology（防务技术） 2024年第6期36卷 95-104页

作者： Eon-ho lee Hyeon Jun Jeon Jinwoo Choi Hyun-Taek Choi Sejin lee The Department of Mechanical Engineering Kongju National University1223-24 Cheonan-daeroCheonan 31080Republic of Korea Ocean System Engineering Research Division Korea Research Institute of Ships and Ocean Engineering(KRISO)Daejeon 34103Republic of Korea The Division of Mechanical&Automotive Engineering Kongju National University1223-24 Cheonan-daeroCheonan 31080Republic of Korea

Swarm robot systems are an important application of autonomous unmanned surface vehicles on water *** monitoring natural environments and conducting security activities within a certain range using a surface vehicle,the swarm robot system is more efficient than the operation of a single object as the former can reduce cost and save *** is necessary to detect adjacent surface obstacles robustly to operate a cluster of unmanned surface *** this purpose,a LiDAR(light detection and ranging)sensor is used as it can simultaneously obtain 3D information for all directions,relatively robustly and accurately,irrespective of the surrounding environmental *** the GPS(global-positioning-system)error range exists,obtaining measurements of the surface-vessel position can still ensure stability during platoon *** this study,a three-layer convolutional neural network is applied to classify types of surface *** aim of this approach is to redefine the sparse 3D point cloud data as 2D image data with a connotative meaning and subsequently utilize this transformed data for object classification ***,we have proposed a descriptor that converts the 3D point cloud data into 2D image *** use this descriptor effectively,it is necessary to perform a clustering operation that separates the point clouds for each *** developed voxel-based clustering for the point cloud ***,using the descriptor,3D point cloud data can be converted into a 2D feature image,and the converted 2D image is provided as an input value to the *** intend to verify the validity of the proposed 3D point cloud feature descriptor by using experimental data in the ***,we explore the feasibility of real-time object classification within this framework.

关键词： Object classification Clustering 3D point cloud data LiDAR(light detection and ranging) Surface vehicle

SUMS OF DUAL TOEPLITZ PRODUCTS ON THE ORTHOGONAL COMPLEMENTS OF FOCK-SOBOLEV SPACES

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Acta Mathematica Scientia 2024年第3期44卷 810-822页

作者：陈泳 Young Joo lee Department of Mathematics Hangzhou Normal UniversityHangzhou311121China Department of Mathematics Chonnam National UniversityGwangju61186Korea

We consider dual Toeplitz operators on the orthogonal complements of the FockSobolev spaces of all nonnegative real ***,for symbols in a certain class containing all bounded functions,we study the problem of when an operator which is finite sums of the dual Toeplitz products is compact or ***,for bounded symbols,we construct a symbol map and exhibit a short exact sequence associated with the C^(*)-algebra generated by all dual Toeplitz operators with bounded symbols.

关键词： dual Toeplitz operators Fock-Sobolev spaces symbol map

Synergistically coupling of Ni–Fe LDH arrays with hollow Co–Mo sulfide nanotriangles for highly efficient overall water splitting

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Rare Metals 2024年第2期43卷 522-532页

作者： Yun Jae lee Seung-Keun Park Department of Advanced Materials Engineering Chung-Ang UniversityAnseongGyeonggi-do17546Republic of Korea Department of Intelligent Energy and Industry Chung-Ang University84 Heukseok-ro Dongjak-guSeoul06974Republic of Korea Western Seoul Center Korea Basic Science Institute150 Bugahyeon-roSeodaemun-guSeoul03759Republic of Korea

Developing bifunctional catalysts that can catalyze both oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)is pivotal to commercializing large-scale water ***,a novel hollow nanotriangle composed of NiFe LDH-CoMoS_(x) heterojunction(H-CMSx@NiFe LDH)is proposed as a highly efficient bifunctional electrocatalyst for both OER and *** fabricate a heterojunction system,ultra-thin nickel–iron layered double hydroxide(NiFe LDH)nanosheets are uniformly electrodeposited onto a metal–organic framework-derived hollow CoMoS_(x) *** strong coupling of CoMoS_(x) and NiFe LDH catalysts forms the intimate heterojunction interfaces to facilitate interfacial charge transfer,which is favorable to enhance the bifunctional catalytic ***,the large void of CoMoS_(x) nanotriangles and interconnected ultra-thin NiFe LDH nanosheets result in good electrolyte penetration and gas ***,the as-prepared H-CMSx@NiFe LDH on nickel foam(NF)exhibits an impressive catalytic activity and durability for OER and HER activities,delivering a current density of 100 mA·cm^(−2) at the small overpotentials of 214 and 299 mV in OER and HER,***,H-CMSx@NiFe LDH/NF proves to be an effective electrode for an alkaline electrolyzer,as a voltage of only 1.99 V is enough to achieve a current density voltage of only 1.99 V is enough to achieve a current density of 400 mA·cm^(−2) with no degradation in performance over 50 h.

关键词： Overall water splitting Metal-organic framework Molybdenum sulfide Layered double hydroxide Heterojunction

Comparison of Lumbopelvic-Hip Rotation Asymmetry and Pelvic Asymmetry between Individuals with and without Nonspecific Low Back Pain

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Journal of Biosciences and Medicines 2024年第9期12卷 314-328页

作者： Qianhui Sun Heng-Ju lee Cheng-feng Lin Rakhmad Rosadi Department of Physical Education and Sport Sciences National Taiwan Normal University Taipei City Department of Physical Therapy National Cheng Kung University Tainan Department of Physiotherapy Faculty of Health Science University of Muhammadiyah Malang Malang Indonesia

Background: low back pain affects many individuals, with 80% classified as non-specific low back pain (NSLBP) due to mechanical rather than structural issues. The link between pelvic alignment and lumbopelvic-hip rotation movement for NSLBP is controversial. Methods: twenty males with NSLBP and 20 healthy males participated. Data collected included static pelvic asymmetry and active lumbopelvic-hip rotation with motion capture system for kinematic analysis. Results: Unpaired T test was used to compare the difference of kinematic parameters between two groups. NSLBP group showed significantly larger angles between the ASIS-PSIS line and the z-axis (p Conclusion: Evaluations focusing on bone structure alone may be inadequate. A more comprehensive approach including functional assessments like muscle strength and range of motion could be beneficial. Integrating lumbopelvic-hip movement patterns and pelvic symmetry into clinical assessments should be considered, as they may be influenced by physical activity.

关键词： Low Back Pain Biomechanics Pelvic Alignment