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Particles in a circulation loop for solar energy capture and storage

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Particuology 2019年第2期17卷 149-156页

作者： Q. Kang G. Flamant R. Dewil J. Baeyens h.l. zhang Y.M. Deng KU leuven Department of Chemical Engineering Process and Environmental Technology Lab. 2860 Sint-Katelijne-Waver Belgium Processes. Materials and Solar Energy laboratory PROMES-CNRS 66120 Font Romeu France European Powder & Process Technology 3120 Tremelo Belgium Beijing University of Chemical Technology School of Life Science and Technology Beijing 10029 China

This study defines and assesses the selection ciiteria for suitable particulate materials to be used in an upflow bubbling fluidized bed (UBFB) or dense up-flow powder circulation system for solar energy capture and storage. The main criteria identified are based on the thermophysical and thermomechanical properties, attrition behavior, and the considerations of health and environmental hazards of the candidate powders. Finally, a cost comparison and tentative ranking of the different can didate powders is presented in addition to a weighted scoring. Significant scoring differences can be observed between the various materials. Olivine possesses the most favorable characteristics and appears to be the particulate material of choice for solid/gas suspension heat transfer fluids.

关键词： Concentrated solar power Particle-in-tube receiver Particle properties Selection criteria

EFFECTS OF lINEAR ElECTROMAGNETIC STIRRING ON ThE SOlIDIFICATION STRUCTURE OF BIllET

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Acta Metallurgica Sinica(English.l.tters) 2001年第3期14卷 227-234页

作者： h.l. zhang, E.G. Wang, G.l. Jia and J.C. he (Key laboratory of National Education Ministry for Electromagnetic Processing of Materials, Northeastern University, Shenyang 110004, China) Northeastern Univ. Shenyang 110004 China

The effects of linear electromagnetic stirring (EMS) on the solidification structure of billet were investigated by experiments, and the electromagnetic field and the flow field during the stirring process were analyzed by numerical simulation. The results show that the billet of almost 100% equiaxed grains can be obtained by applying linear EMS at the maximum intensity of 1414 A·hz1/2, wh.l. the maximum electromagnetic force and the maximum velocity in the molten steel are 6386 N·m-3 and 0.22 m·s-1 respectively. It is shown that in the pulsating electromagnetic force which is perpendicular to the movement of the molten steel is an important factor of increasing the equiaxed zone ration in the solidification structure, which further prevents the appearance of white band and internal defects.

关键词： Computer simulation Grain growth Magnetoelectric effects Mixing Solidification

In situ TEM investigation of electron irradiation and aging-induced high-density nanoprecipitates in an Mg-10Gd-3Y-1Zn-0.5Zr alloy

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Journal of Magnesium and Alloys 2024年第5期12卷 1841-1853页

作者： M.lv h.l.Ge Q.Q.Jin X.h.Shao Y.T.Zhou B.zhang X.l.Ma Shenyang National laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Materials Science and Engineering Research Center Guangxi University of Science and TechnologyLiuzhou 545006China

In-situ electron irradiation and aging are applied to introduce high-density precipitates in an Mg-10Gd-3Y-1Zn-0.5Zr(GWZ1031K,wt.%)alloy to improve the *** results show that the hardness of the Mg alloy after irradiation for 10 h and aging for 9 h at 250℃ is 1.64 GPa,which is approximately 64% higher than that of the samples before being *** is mainly attributed to γ'precipitates on the basal plane after irradiation and the high-density nanoscale β'precipitates on the prismatic plane after aging,which should be closely related to the irradiation-induced homogenous *** latter plays a key role in precipitation *** result paves a way to improve the mechanical properties of metallic materials by tailoring the precipitation through irradiation and aging.

关键词： Mg alloy Electron beam irradiation hardening Precipitates In-situ TEM

Discovery of new MAX-phase-like layered ternary carbide V_(8)P_(6)C:Crystal structure,thermal expansion,and elastic properties

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Journal of Materials Science & Technology 2024年第7期174卷 55-62页

作者： h.X.Chen l.Sheng Z.l.zhang X.C.Wen D.l.Yang X.Y.Ye P.Q.Dai School of Materials Science and Engineering Fujian University of TechnologyFuzhou 350118China Beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of ScienceBeijing 100049China Fujian Provincial Key laboratory of Advanced Materials Processing and Application Fuzhou 350118China State Key laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China

Due to the laminated structure,MAX phases and MAX-phase-like compounds possess outstanding dam-age tolerance capability with good thermal/electrical conductivity and other charming functional prop-erties,showing a bright future for structural-functional ***,a new MAX-phase-like ternary car-bide V_(8)P_(6)C with.l.yered characteristics was *** to the alternate stacking of hexagonal-arranged M/A/X atom layers in MAX phases,V_(8)P_(6)C has a layered structure formed by a repeated stacking of the slabs consisting of V_(6)C-octahedrons and VP 6-distorted-octahedrons in three-atomic layers *** thermal expansion anisotropy was revealed,with the thermal expansion coefficients(TECs)along a-axis,c-axis,and the average value,equal toα_(a)=8.55(5)μK^(−1),α_(c)=10.23(5)μK^(−1),andα_(l)=9.14(5)μK^(−1),*** dilation along the c-axis was mainly dominated by out-plane V-P bonds be-tween layered *** to the pressure-dependent lattice parameters,the polycrystalline bulk modulus(B_(0)=185(9)GPa)and high compressibility anisotropy factor(B_(a)/B_(c)=1.64)was ***-wh.l.,the second-order elastic constants were calculated,and the elastic moduli,E=303 GPa,B=198 GPa,G=122 GPa,andν=0.246,were *** the weak connection between layer slabs by out-plane V1-P bond was revealed by the bond stiffness model,with a bond stiffness close to the M-A bond in MAX ***,good damage tolerance capability was predicted according to Paugh’s ratio(G/B=0.616)and Cauchy pressure(P_(a)=0 GPa,P_(c)=-7.5 GPa),even better than those of typical MAX *** discovery of V_(8)P_(6)C provides a new member of MAX-phase-like damage-tolerant ceramic with relatively low density,moderate thermal expansion,and anisotropic compressibility,and the unique lay-ered structure is inspiring for exploring new layered ternary ceramics.

关键词： New ternary carbide MAX phase Thermal expansion Elastic constants Anisotropy

Rational design of AgGaS/ZnS/ZnS quantum dots with a near-unity photoluminescence quantum yield via double sh.l.ing scheme

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Journal of Materials Science & Technology 2024年第2期169卷 235-242页

作者： h.X.lu h.l.u Z.Z.Fu Y.Y.Chen h.Q.Dai Z.hu W.l.zhang R.Q.Guo Institute for Electric light Sources School of Information Science and TechnologyFudan UniversityShanghai 200433China Institute of Future lighting Academy for Engineering and TechnologyFudan UniversityShanghai 200433China Yiwu Research Institute of Fudan University YiwuZhejiang 322000China Zhongshan-Fudan Joint Innovation Center Zhongshan 528437China

In this study,a two-step method was used to synthesize highly luminescent AgGaS/ZnS/ZnS quantum dots(QDs).In the first step,an inner ZnS sh.l. was formed via a one-pot method,which resulted in a smaller lattice mismatch between the AgGaS core and the outer ZnS sh.l.,thereby facilitating the formation of a thick outer *** the two-step sh.l.ing process,the synthesized AgGaS/ZnS/ZnS QDs showed an excellent photoluminescence quantum yield(PlQY)of 96.4%with a peak wavelength of 508 nm,repre-senting the highest PlQY reported thus far for AgGaS ***,the effect of h.l.gen ions in Zn precursors on the sh.l.ing process was *** was proposed that the capacity of h.l.gen ions to coordinate with the QDs influenced the balance between Zn cation diffusion and ZnS sh.l.ing ***,the ZnS sh.l.ing reaction was dominant when ZnCl_(2)was employed,wh.l. Zn cation diffusion was the dominant process under the I^(−)-rich *** work provides insights into the interfacial restructuring during the ZnS sh.l.ing and offers a clear map for the tailored synthesis of core/sh.l. QDs.

关键词： AgGaS Quantum dots Photoluminescence Core/sh.l. Alloyed core/sh.l. interface

Precipitation of multi-type nano-quasicrystals in a Mg-Zn-Y alloy

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Journal of Magnesium and Alloys 2024年第3期12卷 997-1008页

作者： W.Z.Wang X.Z.Zhou l.F.zhang h.Q.Ye Z.Q.Yang Shenyang National laboratory for Materials Science Institute of Metal ResearchChinese Academy of ScienceShenyang 110016China Ji hua laboratory Foshan 528251China Foshan University Foshan 528231China

Mg-6Zn-1Y(at.%)ribbons with strengthening precipitates of multi-type nanoquasicrystals were prepared by melt-spinning followed by aging *** evolution of the rapidly solidified ribbons during isothermal aging was comprehensively studied using various electron microscopy *** new kinds of decagonal quasicrystals were formed in aged ribbons,in addition to precipitation of nanometer icosahedral ***-resolution observations reveal that both decagonal quasicrystals can be modeled by quasiperiodic tiling with decagonal clusters of 2.5 nm in diameter,but overlap of neighboring clusters in both decagonal quasicrystals is different from the Gummelt model observed in other quasicrystals.A sh.l. composed of complex laves Mg-Zn domains was formed surrounding each decagonal quasicrystal precipitate upon prolonged *** addition,all kinds of nanoprecipitates exhibit excellent structure and size stability at 573 *** findings may have implications for not only fundamental studies about quasicrystals,but also microstructural manipulation of high-performance Mg alloys.

关键词： Quasicrystal Mg alloys Rapid solidification Scanning-transmission electron microscopy.

Cognition on oxidation behavior of Ni-based superalloy Gh4742 when exposed to water vapor

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Journal of Materials Science & Technology 2024年第7期174卷 15-22页

作者： h.Xu S.F.Yang E.h.Wang C.Y.Guo Y.S.liu X.M.hou Y.l.zhang State Key laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Institute for Carbon Neutrality University of Science and Technology BeijingBeijing 100083China

The oxidation behavior of Ni-based superalloy Gh4742 exposed to water vapor was investigated at 900-1100℃for 50 h in Ar+20%h_(2)O,with Ar+20%O_(2)included for *** presence of h_(2)O is adverse to formation of continuous Cr_(2)O_(3)oxide layer but contributes to generation of big *** on this,Ni^(2+)and Co^(2+)are more easily to diffuse towards the outermost oxide layer(OOl),forming non-protective Ni-and Co-rich oxides with high *** leads to a higher weight gain in Ar+20%h_(2)O than that in Ar+20%O_(2).At elevated temperatures,the spallation of oxide scale occurs wh.l. the consumption of Cr is reduced in Ar+20%h_(2)O,and the contents of Ni-and Co-rich oxides at this moment are reduced in the *** oxidation mechanism was also discussed.

关键词： Gh4742 Superalloy h_(2)O Diffusion Oxidation Mechanism

location of Asymmetric Ground Fault Using Virtual Injected Current Ratio and Two-stage Recovery Strategy in Distribution Networks

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 151-161页

作者： haiting Shan luliang zhang Q.h.Wu Mengshi li School of Electric Power Engineering South China University of Technology(SCUT)Guangzhou 510641China

Sparse measurements ch.l.enge fault location in distribution *** paper proposes a method for asymmetric ground fault location in distribution networks with.l.mited measurements.A virtual injected current vector is formulated to estimate the fault line,which can be reconstructed from voltage sags measured at a few buses using compressive sensing(CS).The relationship between the virtual injected current ratio(VICR)and fault position is deduced from circuit analysis to pinpoint the ***,a two-stage recovery strategy is proposed for improving reconstruction accuracy of the current vector,where two different sensing matrixes are utilized to improve the *** proposed method is validated in IEEE 34 node test *** results show asymmetric ground fault type,resistance,fault position and access of distributed generators(DGs)do not significantly influence performance of our *** addition,it works effectively under various scenarios of noisy measurement and line parameter *** on 134 node test feeders prove the proposed method is also suitable for systems with more complex structure.

关键词： Distribution networks fault location reconstruction accuracy two-stage recovery virtual injected current ratio

high-efficiency Carbonation Modification Methods of Recycled Coarse Aggregates

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Journal of Wuhan University of Technology(Materials Science) 2024年第2期39卷 386-398页

作者：张美香 YANG Xiaolin 丁亚红 SUN Bo zhang Xianggang lÜXiuwen Department of Civil Engineering Henan Polytechnic UniversityJiaozuo 454150China College of Architectural Engineering Xinyu UniversityXinyu 336500China

To solve the problem of only surface carbonation and realize high-efficiency carbonation of recycled coarse aggregate,the method of carbonated recycled coarse aggregate with nano materials pre-soaking was first put *** carbonation effect of modified recycled coarse aggregate with three different carbonation methods was evaluated,and water absorption,apparent density and crush index of modified recycled coarse aggregate were *** with XRD,SEM,and MIP microscopic analysis,the high-efficiency carbonation strengthening mechanism of modified recycled coarse aggregate was *** experimental results show that,compared with the non-carbonated recycled coarse aggregate,the physical and microscopic properties of carbonated recycled coarse aggregate are *** method of carbonation with nano-SiO_(2) pre-soaking can realize the high-efficiency carbonation of recycled coarse aggregate,for modified recycled coarse aggregate with the method,water absorption is reduced by 23.03%,porosity is reduced by 44.06%,and the average pore diameter is 21.82 *** high-efficiency carbonation strengthening mechanism show that the pre-socked nano-SiO_(2) is bound to the hydration product Ca(Oh)_(2) of the old mortar with nano-scale C-S-h,which can improve the CO_(2) absorption rate,accelerate the carbonation reaction,generate more stable CaCO_(3) and nano-scale silica gel,and bond to the dense three-dimensional network structure to realize the bidirectional enhancement of nano-materials and pressurized *** is concluded that the method of carbonation with nano-SiO_(2) pre-soaking is a novel high-efficiency carbonation modification of recycled coarse aggregate.

关键词： recycled coarse aggregate pressurized carbonation high-efficiency carbonation nano-SiO2 strengthening mechanism