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How Common can the Origin of Clusters Cha Ⅰ, Cha Ⅱ, ∈Cha and η Cha be?

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Research in Astronomy and Astrophysics 2024年第5期24卷 28-34页

作者： v.v.Bobylev A.T.Bajkova Pulkovo Astronomical Observatory St.-Petersburg 196140Russia

The trajectories of the groupings η Cha,∈Cha and Cha I,Cha II,constructed backward in time,have been *** concluded that the hypothesis about the joint formation of all four of these clusters from one molecular cloud cannot be completely ***,10–15 Myr ago,all these four clusters were located at approximately the same height above the plane of the ***,the gas-dust clouds from which all these four clusters were formed were located on one broad *** is possible that the appearance of the Cha I,Cha II,∈Cha and η Cha clusters may be associated with the impact on such a front of shock waves formed after supernova explosions in the Scorpius–Centaurus *** estimates of the kinematic ages of the clusters Cha I and Cha II are obtained as 0.12±0.19 and 0.05±0.15,*** is shown that the minimum size of the Cha I-north and Cha I-south clusters corresponded to the time of 0.55±0.24 Myr and 0.04±0.18 Myr ago,respectively,and approximately1.5 Myr ago the distance between the trajectories of these two groupings was minimal.

关键词： stars distances-stars kinematics and dynamics-galaxies star formation

Sequential reactant water management by complementary multisite catalysts for surpassing platinum hydrogen evolution activity

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Nano Research 2024年第3期17卷 1232-1241页

作者： yu Lin Defang Ding Shicheng Zhu Qunlei Wen Huangjingwei Li Zhen Li Youwen Liu Yi Shen China Engineering Research Center of Nano-Geomaterials of Ministry of Education Faculty of Materials Science and ChemistryChina University of GeosciencesWuhan 430078China State Key Laboratory of Materials Processing and Die&Mould Technology and School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

Alkaline hydrogen evolution reaction(HER)offers a near-zero-emission approach to advance hydrogen ***,the activity limited by the multiple reaction steps involving H_(2)O molecules transfer,absorption,and activation still unqualified the thresholds of economic ***,we proposed a multisite complementary strategy that incorporates hydrophilic Mo and electrophilic v into Ni-based catalysts to divide the distinct steps on atomically dispersive sites and thus realize sequential regulation of the HER *** Isotopic labeled in situ Raman spectroscopy describes 4-coordinated hydrogen bonded H_(2)O to be free H_(2)O passing the inner Helmholtz plane in the vicinity of the catalysts under the action of hydrophilic Mo ***,potential-dependent electrochemical impedance spectroscopy(EIS)reveals that electrophilic v sites with abundant 3d empty orbitals could activate the lone-pair electrons in the free H_(2)O molecules to produce more protic hydrogen,and dimerize into H_(2) at the Ni *** the sequential management of reactive H_(2)O molecules,NiMov oxides multisite catalysts surpass Pt/C hydrogen evolution activity(49 mv@10 mA∙cm^(-2) over 140 h).Profoundly,this study provides a tangible model to deepen the comprehension of the catalyst–electrolyte interface and create efficient catalysts for diverse reactions.

关键词： hydrogen evolution activity complementary multisite catalysts sequential reactive water management interfacial water molecules

Cross-method Analysis of Corotation Radii Data Set for Spiral Galaxies

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Research in Astronomy and Astrophysics 2024年第7期24卷 95-110页

作者： v.S.Kostiuk A.A.Marchuk A.S.Gusev Sternberg Astronomical Institute Lomonosov Moscow State UniversityUniversitetsky pr.13119234 MoscowRussia Central(Pulkovo)Astronomical Observatory Russian Academy of SciencesPulkovskoye chaussee 65/1196140 St.PetersburgRussia Saint Petersburg State University Universitetsky pr.28198504 St.PetersburgRussia

A corotation radius is a key characteristic of disk galaxies that is essential to determine the angular speed of the spiral structureΩ_p,and therefore understand its *** the literature,there are plenty of methods to estimate this value,but do these measurements have any consistency?In this work,we collected a data set of corotation radius measurements for 547 galaxies,300 of which had at least two *** initial analysis reveals that most objects have rather inconsistent corotation radius ***,a significant fraction of galactic disks is distinguished by a large error coverage and almost uniform distribution of *** findings do not have any relation to spiral type,Hubble classification,or presence of a *** other reasons,obtained results could be explained by the transient nature of spirals in a considerable part of *** have made our collected data sample publicly available,and have demonstrated on one example how it could be useful for future research by investigating a winding time value for a sample of galaxies with possible multiple spiral arm patterns.

关键词： galaxies fundamental parameters-galaxies kinematics and dynamics-galaxies structure

Supporting IrO_(x) nanosheets on hollow TiO_(2) for highly efficient acidic water splitting

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Nano Research 2024年第8期17卷 6903-6909页

作者： Ge yu Ruilong Li Yanmin Hu Xingen Lin Ze Lin Dongyang Wu Gongming Wang Xun Hong Center of Advanced Nanocatalysis(CAN) Department of Applied ChemistryUniversity of Science and Technology of ChinaHefei 230026China

The efficiency of proton exchange membrane water electrolysis(PEM-WE)for hydrogen production is heavily dependent on the noble metal iridium-based ***,the scarcity of iridium limits the large-scale application of *** address this issue,it is promising to select an appropriate support because it not only enhances the utilization efficiency of noble metals but also improves mass transport under high ***,we supported amorphous IrO_(x) nanosheets onto the hollow TiO_(2) sphere(denoted as IrO_(x)),which demonstrated excellent performance in acidic electrolytic water ***,the annealed IrO_(x)catalyst at 150℃in air exhibited a mass activity of 1347.5 A·gIr^(−1),which is much higher than that of commercial IrO_(2) of 12.33 A·gIr^(−1) at the overpotential of 300 mv for oxygen evolution reaction(OER).Meanwhile,the annealed IrO_(x) exhibited good stability for 600 h operating at 10 mA·cm^(−2).Moreover,when using IrO_(x) and annealed IrO_(x) catalysts for water splitting,a cell voltage as low as 1.485 v can be achieved at 10 mA·cm^(−2).The cell can continuously operate for 200 h with negligible degradation of performance.

关键词： oxygen evolution reaction hydrogen evolution reaction amorphous IrO_(x) hollow TiO_(2) proton exchange membrane water electrolysis

Phase transition of multi-component(TiZrvNb)C ceramics—Part I:Phase decomposition induced by carbon content

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Journal of Advanced Ceramics 2024年第5期13卷 679-688页

作者： Qingyi Kong Rao Zhang Lei Chen Sijia Huo Wenyu Lu yujin Wang Boxin Wei yu Zhou Institute for Advanced Ceramics School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150080China Key Laboratory of Advanced Structure‒Function Integrated Materials and Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001China School of Materials Science and Chemical Engineering Harbin University of Science and TechnologyHarbin 150001China National Key Laboratory of Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China

Phase decomposition can effectively enhance the mechanical properties of carbide ceramics and can overcome the difficulty of enhancing the mechanical properties of single-phase multicomponent carbide *** this work,a series of nonstoichiometric(TiZrvNb)Cx ceramics were prepared by spark plasma sintering(SPS)at different *** effects of the carbon content on the phase composition,microstructure evolution,and mechanical properties were investigated in *** decomposition occurred with decreasing carbon *** different solid solutions of(Ti,v)-rich and Zr-rich phases formed from the decomposition of equimolar single-phase solid solutions,namely,the Zr-poor phase and Zr-rich phase,*** distribution of Nb element is relatively *** semicoherent interfaces between the Zr-poor phase and the Zr-rich phase can harden and strengthen effectively under the synergistic effect of grain *** with phase decomposition structures have apparent advantages compared to single-phase high-entropy *** work provides an important train of thought for the microstructure tailoring and properties optimization of multi-component carbide ceramics.

关键词： multicomponent ceramics nontoichiometry microstructure evolution phase decomposition mechanical properties

Crafting chirality in three dimensions via a novel fabrication technique for bound states in the continuum metasurfaces

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Light(Science & Applications) 2024年第3期13卷 390-392页

作者： Zaid Haddadin Anna My Nguyen Lisa v.Poulikakos Department of Electrical&Computer Engineering University of California San DiegoLa JollaCAUSA Department of Mechanical&Aerospace Engineering University of California San DiegoLa JollaCAUSA Program of Materials Science&Engineering University of California San DiegoLa JollaCAUSA

An additional deposition step was added to a multi-step electron beam lithographic fabrication process to unlock the height dimension as an accessible parameter for resonators comprising unit cells of quasi-bound stat... 详细信息

关键词： dimensions dimension intrinsic

Formation of diffuse and spark discharges between two needle electrodes with the scattering of particles

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Plasma Science and Technology 2024年第9期26卷 32-39页

作者： victor F TARASENKO Dmitry v BELOPLOTOv Alexei N PANCHENKO Dmitry A SOROKIN Institute of High Current Electronics Siberian BranchRussian Academy of SciencesTomsk 634055Russia National Research Tomsk State University Tomsk 634050Russia

The development of a nanosecond discharge in a pin-to-pin gap filled with air at atmospheric pressure has been studied with high temporal and spatial resolutions from a breakdown start to the spark *** and negative nanosecond voltage pulses with an amplitude of tens of kilovolts were ***-resolved images of the discharge development were taken with a fourchannel Intensified Charge Coupled Device(ICCD)*** minimum delay between the camera channels could be as short as≈0.1 *** made it possible to study the gap breakdown process with subnanosecond *** was observed that a wide-diameter streamer develops from the high-voltage pointed *** ionization processes near the grounded pin electrode started when the streamer crossed half of the *** bridging the gap by the streamer,a diffuse discharge was *** development of spark leaders from bright spots on the surface of the pointed electrodes was observed at the next *** was found that the rate of development of the spark leader is an order of magnitude lower than that of the wide-diameter *** thin luminous tracks were observed against the background of a discharge plasma *** has been established that the tracks are adjacent to brightly glowing spots on the electrodes and are associated with the flight of small particles.

关键词： needle electrodes short voltage pulses atmospheric air streamer breakdown diffuse and spark discharges scattering metal particles

Dynamic cooperations between lattice oxygen and oxygen vacancies for photocatalytic ethane dehydrogenation by a self-restoring LavO_(4)catalyst

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Chinese Chemical Letters 2024年第3期35卷 171-176页

作者： Fen Wei Weichao Xue Zhiyang yu Xue Feng Lu Sibo Wang Wei Lin Xinchen Wang State Key Laboratory of Photocatalysis on Energy and Environment College of ChemistryFuzhou UniversityFuzhou 350108China

Thermocatalytic nonoxidative ethane dehydrogenation(EDH)is a promising strategy for ethene production but suffers from intense energy consumption and poor catalyst durability;exploring technology that permits efficient EDH by solar energy remains a giant ***,we present that an oxygen vacancy(O_v)-rich LavO_(4)(LavO_(4)-O_v)catalyst is highly active and stable for photocatalytic EDH,through a dynamic lattice oxygen(O_(latt.))and O_(v)co-mediated *** by simulated sunlight at mild conditions,LavO_(4)-O_(v)effectively dehydrogenates undiluted ethane to produce C_(2)H_(4)and CO with a conversion of 2.3%.By loading a small amount of Pt cocatalyst,the evolution and selectivity of C_(2)H_(4)are enhanced to 275μmol h^(-1)g^(-1)and 96.8%.Of note,LavO_(4)-O_(v)appears nearly no carbon deposition after the *** isotope tracked reactions reveal that the consumed O_(latt.)recuperates by exposing the used catalyst with O_(2),thus establishing a dynamic cycle of O_(latt.)and achieving a facile catalyst regeneration to preserve its intrinsic *** refreshed LavO_(4)-O_(v)exhibits superior reusability and delivers a turnover number of about *** O_(v)promotes photo absorption,boosts ethane adsorption/activation,and accelerates charge separation/transfer,thus improving the photocatalytic *** possible photocatalytic EDH mechanism is proposed,considering the key intermediates predicted by density functional theory(DFT)and monitored by in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS).

关键词： Photocatalysis Ethane dehydrogenation Ethene LavO_(4) Oxygen vacancy

Interatomic Interaction Models for Magnetic Materials:Recent Advances

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Chinese Physics Letters 2024年第6期41卷 54-66页

作者： Tatiana S.Kostiuchenko Alexander v.Shapeev Ivan S.Novikov Emanuel Institute of Biochemical Physics RAS 4 Kosygin StreetMoscow119334Russian Federation Independent investigator

Atomistic modeling is a widely employed theoretical method of computational materials *** has found particular utility in the study of magnetic ***,magnetic empirical interatomic potentials or spinpolarized density functional theory(DFT)served as the primary models for describing interatomic interactions in atomistic simulations of magnetic ***,in recent years,a new class of interatomic potentials known as magnetic machine-learning interatomic potentials(magnetic MLIPs)has *** MLIPs combine the computational efficiency,in terms of CPU time,of empirical potentials with the accuracy of DFT *** this review,our focus lies on providing a comprehensive summary of the interatomic interaction models developed specifically for investigating magnetic *** also delve into the various problem classes to which these models can be ***,we offer insights into the future prospects of interatomic interaction model development for the exploration of magnetic materials.

关键词： materials interaction empirical