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Grain refinement of mg-Ca alloys by native mgO particles

Journal of magnesium and Alloys 2024年第3期12卷 980-996页

作者： Shihao Wang yun Wang Quentin m.Ramasse Zhongyun Fan Super STEm Laboratory SciTech Daresbury CampusDaresbury WA44ADUK School of Chemical and Process Engineering University of LeedsLeeds LS29JTUK BCAST Brunel University LondonUxbridgeMiddlesex UB83PHUK

In mg-Ca alloys the grain refining mechanism,in particular regarding the role of nucleant substrates,remains the object of *** native mgO is being recognised as a nucleating substrate accounting for grain refinement of mg alloys,the possible interactions of mgO with alloying elements that may alter the nucleation potency have not been elucidated ***,we design casting experiments of mg-xCa alloys varied qualitatively in number density of native mgO,which are then comprehensively studied by advanced electron *** results show that grain refinement is enhanced as the particle number density of mgO *** native mgO particles are modified by interfacial layers due to the co-segregation of Ca and N solute atoms at the mgO/mg *** aberration-corrected scanning transmission electron microscopy and electron energy loss spectroscopy,we reveal the nature of these Ca/N interfacial layers at the atomic *** of the crystallographic termination of mgO,Ca and N co-segregate at the mgO/mg interface and occupy mg and O sites,respectively,forming an interfacial structure of a few atomic *** interfacial structure is slightly expanded,less ordered and defective compared to the mgO matrix due to compositional deviations,whereby the mgO substrate is altered as a poorer template to nucleate mg *** solidification in a TP-1 mould,the impotent mgO particles account for the grain refining mechanism,where they are suggested to participate into nucleation and grain initiation processes in an explosive *** work not only reveals the atomic engineering of a substrate through interfacial segregation but also demonstrates the effectiveness of a strategy whereby native mgO particles can be harnessed for grain refinement in mg-Ca alloys.

关键词： mg-Ca alloy Grain refinement mgO Interfacial segregation STEm/EELS Solidification.

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Rebuilding the theory of isotope fractionation for evaporation of silicate melts under vacuum condition

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Acta Geochimica 2024年第4期43卷 661-676页

作者： Jie Wang yun Liu Research Center for Planetary Science College of Earth and Planetary SciencesChengdu University of TechnologyChengdu 610059China State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China CAS Center for Excellence in Comparative Planetology Hefei 230026China

Isotope eff ects are pivotal in understanding silicate melt evaporation and planetary accretion *** on the Hertz-Knudsen equation,the current theory often fails to predict observed isotope fractionations of laboratory experiments due to its oversimplified ***,we point out that the Hertz-Knudsen-equation-based theory is incomplete for silicate melt evaporation cases and can only be used for situations where the vaporized species is identical to the one in the *** propose a new model designed for silicate melt evaporation under *** model considers multiple steps including mass transfer,chemical reaction,and *** derivations reveal a kinetic isotopic fractionation factor(KIFF orα)αour model=[m(^(1)species)/m(^(2)species)]^(0.5),where m(species)is the mass of the reactant of reaction/nucleation-limiting step or species of diffusion-limiting step and superscript 1 and 2 represent light and heavy isotopes,*** model can eff ectively reproduce most reported KIFFs of laboratory experiments for various elements,i.e.,mg,Si,K,Rb,Fe,Ca,and ***,the KIFF-mixing model referring that an overall rate of evaporation can be determined by two steps jointly can account for the eff ects of low P_(H2)pressure,composition,and *** addition,we find that chemical reactions,diffusion,and nucleation can control the overall rate of evaporation of silicate melts by using the fitting slope in ln(−ln f)versus ln(t).Notably,our model allows for the theoretical calculations of parameters like activation energy(E_(a)),providing a novel approach to studying compositional and environmental eff ects on evaporation processes,and shedding light on the formation and evolution of the proto-solar and Earth-moon systems.

关键词： Evaporation Kinetic isotopic fractionation Chemical kinetics Hertz-Knudsen equation CAIS

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Holographic Polymer Nanocomposites with High Refractive Index modulation by Doping Liquid Crystal E6m

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Chinese Journal of Polymer Science 2024年第7期42卷 926-935,I0006页

作者： meng-yun Wang Yue Zhang Dan Wang ming Yao Yi-Xuan Wang Xing-Ping Zhou Hai-Yan Peng Xiao-Lin Xie Key Laboratory of material Chemistry for Energy Conversion and Storage Ministry of EducationSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan430074China State Key Laboratory of materials Processing and Die&mould Technology Huazhong University of Science and TechnologyWuhan430074China National Anti-counterfeit Engineering Research Center Huazhong University of Science and TechnologyWuhan430074China

Holographic optical elements(HOEs)based on polymer composites have become a research hot spot in recent years for augmented reality(AR)due to the significant improvement of optical performance,dynamic range,ease of processing and high yield ***,it remains a formidable challenge to obtain a large field of view(FOV)and brightness due to the limited refractive index ***,we report an effective method to tackle the challenge by doping an epoxy liquid crystal termed E6m,which enables a large refractive index modulation of 0.050@633 nm and low haze of 5.0%at a doping concentration of 5 wt%.This achievement may be ascribed to the improved molecular ordering of liquid crystals within the holographic polymer *** high refractive index modulation can endow transmission-type holographic polymer composites with a high diffraction efficiency of 96.2%at a small thickness of 5μm,which would promise the design of thin and lightweight AR devices.

关键词： Polymer nanocomposites Holography AR/VR Refractive index modulation Liquid crystal

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Optimized Selection method of Air Combat Course of Action under Stochastic Uncertainty

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Journal of Systems Science and Systems Engineering 2024年第4期33卷 494-518页

作者： yun Zhong Jieyong Zhang Peng Sun Lujun Wan Kepeng Wang Information and Navigation College Air Force Engineering UniversityXi’an710077China Equipment management and Unmanned Aerial Vehicle Engineering College Air Force Engineering UniversityXi’an710051China Air Traffic Control and Navigation College Air Force Engineering UniversityXi’an710051China Unit 94040 of PLA Korla841000China

Aiming at the design problem of aviation swarm combat course of action(COA),considering the influence of stochastic parameters in the causal relationship model and optimization problem model,according to the dynamic influence net(DIN)theory,stochastic simulation technique,feedforward neural network(FNN)function approximation technique and multi-objective artificial fish school algorithm(mOAFSA),this paper proposed a COA optimized method based on DIN and multi-objective stochastic chance constraint optimization for aviation swarm ***,on the basis of establishing the overall framework of the model and defining the elements of causal relationship modeling,the static and dynamic causal relationship modeling and optimization problem modeling were carried out ***,the probability propagation mechanism of DIN was established,which mainly included two aspects,i.e.,the overall process and the specific ***,input and output data were generated based on stochastic *** to these data,FNN was adopted for function approximation,and mOAFSA was adopted for iterative ***,the rationality of the model,and the effectiveness and superiority of the algorithm were verified through multiple sets of simulation cases.

关键词： Stochastic uncertainty aviation swarm stochastic simulation course of action feedforward neural network multi-objective artificial fish school algorithm

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One dimensional pea-shaped NiSe_(2) nanoparticles encapsulated in N-doped graphitic carbon fibers to boost redox reversibility in sodium-ion batteries

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Journal of materials Science & Technology 2024年第1期168卷 215-226页

作者： Hyunjeong Gim Achmad Yanuar maulana Jiwon Choi Jungwook Song Boram yun Yuri Jeong Nahyun An myeongkee Park Cybelle m.Futalan Jongsik Kim Department of Chemical Engineering(BK21 FOUR Graduate Program) Dong-A UniversityBusan 49315Korea(the Republic of) Department of Chemistry Dong-A UniversityBusan 49315Korea(the Republic of) Department of Chemistry Pukyong National UniversityBusan 48513Korea(the Republic of) Institute of Civil Engineering University of the PhilippinesDiliman 1127Philippines

In recent years,sodium-ion batteries(SIBs)have emerged as a promising technology for energy storage systems(ESSs)because of the abundance and affordability of ***,metal selenides have been studied as promising high-performance conversion-type anode materials in *** them,nickel se-lenide(NiSe_(2))has received considerable attention due to its high theoretical capacity of 495 mAh g^(-1)and ***,it still suffers from poor cycling stability because of the low electrochemical reactivity,large volume expansion,and structural instability during *** address these challenges,NiSe_(2)nanoparticles encapsulated in N-doped graphitic carbon fibers(NiSe_(2)@NGCF)were synthesized by using ZIF-8 as a ***_(2)@NGCF showed a high discharge capacity of 558.3 mAh g^(-1)with a fading rate of 0.14%per cycle after 200 cycles at 0.5 A g^(-1)in 0.01-3.0 *** a very high current density of 5 A g^(-1),the capacity still displayed excellent long-term cycle life with a discharge capacity of 406.1 mAh g^(-1)with a fading rate of 0.016%per cycle after 3000 *** mechanism of the excellent electrochem-ical performance of NiSe_(2)@NGCF was thoroughly investigated by ex-situ XRD,TEm,and SEm ***,NiSe_(2)@NGCF//Na_(3)V_(2)(PO_(4))_(3)full-cell also delivered an excellent reversible capacity of 378.7 mAh g^(−1)at 0.1 A g^(−1)after 50 cycles,demonstrating its potential for practical application in SIBs.

关键词： Sodium-ion batteries Anode materials Nickel selenide N-doped graphitic carbon fibers One-dimensional electrode

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Organic Brønsted Acid-Catalyzed Stereoselective Cationic RAFT Polymerization:The Effect of RAFT Agents

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Chinese Journal of Polymer Science 2024年第6期42卷 711-717页

作者： Zheng-Yi Zhang Zan Yang yun Liao Sai-Hu Liao Key Laboratory of molecule Synthesis and Function Discovery(Fujian Province University) College of ChemistryFuzhou UniversityFuzhou350108China State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen361005China Beijing National Laboratory for molecular Sciences Beijing100190China

The tacticity of vinyl polymers is a key factor affecting the properties of ***,organic Brønsted acids have been demonstrated as effective catalysts for the development of highly stereoselective cationic reversible addition-fragmentation chain transfer(RAFT)polymerizations of vinyl ethers,in which the use of RAFT agents could allow the control the molecular weight and tacticity of polymer products ***,the effect of RAFT agents on the tacticity-regulation remains elusive and lacks of *** this study,we synthesized four types of RAFT agents and evaluated their influence in the stereoselective cationic polymerization of isobutyl vinyl ether in the presence of PADI as a Brønsted acid catalyst,which unveils that the Z group of RAFT agents could not only affect the polydispersity of the products,but also exert a profound effect on the *** extensive screening of the RAFT agents,high stereoregularity(isotacticity,90%m)was obtained when using dithiocarbonate ester-type RAFT agents with a benzyloxy Z group.

关键词： Bronsted acid catalysis Stereoselective cationic polymerization RAFT polymerization Chain transfer agents Tacticity

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Effects of low molecular weight polysaccharide from Sargassum thunbergii against palmitic acid-induced intracellular lipid accumulation in 3T3-L1 adipocyte and HepG2 cells

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Food Science and human Wellness 2024年第4期13卷 2244-2252页

作者： Hyo-Geun Lee D.P.Nagahawatta m.J.m.S.Kurera Kyung-mo Song yun-Sang Choi You-Jin Jeon min-Cheol Kang Department of marine Life Sciences Jeju National UniversityJeju 63243Republic of Korea Department of Biotechnology Faculty of Agriculture and Plantation ManagementWayamba University of Sri LankaMakanduraGonawila(NWP)60170Sri Lanka Research Group of Food Processing Korea Food Research Institute245Wanju 55365Republic of Korea

Low molecular weight polysaccharides can be isolated from Sargassum thunbergii(LmPST)and in vitro experiments were conducted to evaluate the inhibitory effects on *** natures of LmPST were attained from *** and appraised their LmPST on palmitic acid(PA)induced lipid accretion in Hep G2,and 3T3-L1 *** treatment lessened lipid deposition and intracellular free fatty acid and triglyceride intensities in PA-treated above mentioned *** mechanistic study publicized that LmPST2 significantly suppressed adipogenesis and stimulated the PA-treated 3T3-L1 cells occupied in the lipolysis ***,in PA-treated Hep G2 cells,the free fatty acid oxidation was significantly increased by *** these constructive properties of LmPST2 from ***,is a potential candidate for diminishing the intracellular lipids,and for a therapeutic agent in those conditions.

关键词： Sargassum thunbergii Low molecular weight polysaccharide Lipid accumulation Obesity Liver steatosis

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Special issue on electrochemical energy storage and conversion

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Frontiers in Energy 2024年第2期18卷 125-127页

作者： yun ZHENG Gaixia ZHANG Sixu DENG Jiujun ZHANG Institute of New Energy materials and Engineering School of Materials Science and EngineeringFuzhou UniversityFuzhou 350108China Department of Electrical Engineering École de Technologie Supérieure(ÉTS)Universitédu QuébecMontréalH3C 1K3Canada Department of Chemical and materials Engineering Concordia UniversityMontrealQC H3G 1M8Canada

The escalating global consumption of fossil fuels has significantly elevated the levels of CO_(2)in the atmosphere,leading to an undesirable global energy crisis and environmental *** deployment of renewable energy resources is crucial to mitigate these *** recent years,there has been noteworthy progress in electrochemical energy storage and conversion techniques and devices,including hydrogen energy and fuel cells,advanced energy storage and power batteries,and CO_(2)electrochemical conversion and utilization.

关键词： electrochemical energy elevated

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Surface pollen and modern vegetation in Southern Xinjiang,China

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Science China Earth Sciences 2024年第2期67卷 510-530页

作者： yun ZHANG Lixin CHEN Yaoyao XI Zhaochen KONG Xianguo QIAO State Key Laboratory of Black Soils Conservation and Utilization Northeast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun130102China Institute of Botany Chinese Academy of SciencesBeijing100093China Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China University of Chinese Academy of Sciences Beijing100049China School of Geosciences and Resources China University of Geosciences(Beijing)Beijing100083China

The study of modern pollen,and vegetation can improve the accuracy of paleoenvironmental reconstruction based on fossil pollen data.A total of 188 pollen surface samples were collected from Southern Xinjiang(34°00’–43°00’N,74°00’–94°00’E)in China,with an elevation range of 888–4530 *** pollen and vegetation were studied in the northern region of the Kunlun mountains and the southern region of the Tianshan *** results showed that the surface pollen assemblages on the southern slope of the Tianshan mountains(3530–1124 m)were divided into three pollen zones,namely,montane steppe,montane desert steppe,and montane *** zones were dominated by Artemisia,Chenopodiaceae,and Ephedra *** surface pollen assemblages in the eastern Pamir Plateau(4530–1287 m)could be divided into alpine meadow,montane desert steppe,and montane desert zones,which were predominantly characterized by Artemisia,Chenopodiaceae,and Asteraceae ***,the Southern Tarim Basin(3548–888 m)comprised montane desert steppe and montane desert zones,which was dominated by Artemisia and Chenopodiaceae *** geographic distribution of the surface pollen sites obtained using ArcGIS,the R-value,and Pearson correlation analyses indicated that the over-represented Picea and Pinus pollen were of external origin and were transported by wind,water(rivers),and ice(glacier movement).Over-representation of Ephedra and Nitraria pollen was mainly distributed in the montane desert and desert steppe zones,*** from Chenopodiaceae and Artemisia were over-represented and broadly distributed across Southern *** pollen was concentrated in areas with walnut trees,strongly indicating the presence of local parent *** to the Hybrid Singleparticle Lagrangian Integrated Trajectory model,more Pinus pollen was transported to the Pamir region by external airflows during spring and summer,resulting in its higher surface pollen *** elucidating t

关键词： Surface pollen Vegetation Distribution Picea Southern Xinjiang

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Optical Extinctions of Inter-Arm molecular Clouds in m31:A Pilot Study for the Upcoming CSST Observations

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Research in Astronomy and Astrophysics 2024年第6期24卷 323-333页

作者： Cailing Chen Zheng Zheng Chao-Wei Tsai Sihan Jiao Jing Tang Jingwen Wu Di Li yun Zheng Linjing Feng Yujiao Yang Yuan Liang National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Radio Astronomy and Technology Chinese Academy of SciencesBeijing 100101China Institute for Frontiers in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China Zhejiang Lab Hangzhou 311121China

Recent submillimeter dust thermal emission observations have unveiled a significant number of inter-arm massive molecular clouds in ***,the effectiveness of this technique is limited to its sensitivity,making it challenging to study more distant *** study introduces an alternative approach,utilizing optical extinctions derived from space-based telescopes,with a focus on the forthcoming China Space Station Telescope(CSST).We first demonstrate the capability of this method by constructing dust extinction maps for 17 inter-arm massive molecular clouds in m31 using the Panchromatic Hubble Andromeda Treasury *** analysis reveals that inter-arm massive molecular clouds with an optical extinction(A_(V)) greater than 1.6 mag exhibit a notable A_(V) excess,facilitating their *** majority of these inter-arm massive molecular clouds show an A_(V) around 1 mag,aligning with measurements from our JCmT *** validation using a mock CSST RGB star catalog confirms the method's *** show that the derived A_(V)values using CSST z and y photometries align more closely with the input *** clouds with A_(V)> 1.6 mag can also be identified using the CSST mock *** thus claim that future CSST observation clouds provide an effective way for the detection of inter-arm massive molecular clouds with significant optical extinction in nearby galaxies.

关键词： infrared:stars ISm:clouds Galaxy:structure

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