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Microstructure Evolution and Nanomechanical Behavior of Micro-Area in Molten Pool of Selective Laser Melting(CoCrNi)_(82)Al_(9)Ti_(9)High-Entropy Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第6期37卷 1019-1033页

作者： hong-Wei Zhang Li-Wei lan Zhe-Yu yang Chang-Chun Li Wen-Xian Wang College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan030024China Ministry of Education Key Laboratory of Interface Science and Engineering in Advanced MaterialsTaiyuan University of TechnologyTaiyuan030024China Shanxi-Zhejiang University New Materials and Chemical Research Institute Taiyuan030032China

In this work,the phase evolution mechanism and nanomechanical properties of(CoCrNi))(82)Al_(9)Ti_(9)high-entropy alloy(HEA)prepared by selective laser melting(SLM)in the molten pool were *** HEA contains multiple primary elements and undergoes high-temperature gradient and rapid cooling during *** leads to significant inhomogeneity of nano-scale microstructure characteristics and instability of *** optimizing process parameters,the microstructure evolution at the optimal parameter volume energy density of 440 J/mm^(3)was studied.A phase transition from BCC to FCC occurred in the melt *** the micro-area of the melt pool results in a temperature rise and the combustion-induced loss of Al ***,the Ni element content increases significantly outside the melt *** process enhances the phase stability of FCC and facilitates phase ***,rapid cooling leads to the formation of distinctive ultrafine equiaxial crystals inside the melt pool,accompanied by the generation of intracrystalline needle-like nano-scale *** the melt pool,the accumulation of energy results in the formation of coarse ***,the nano-hardness inside the molten pool is remarkably high at 11.79 GPa,while the outside the molten pool is reduced to 9.58 *** the fracture toughness outside the melt pool also *** with inside the melt pool,the residual stress outside the melt pool changed from compressive to tensile stress and decreased from 603.28 to 322.84 MPa.

关键词： High-entropy alloys Selective laser melting Microstructure evolution Nanoindentation

Model for estimating the weight-loss ratio of damaged Korla fragrant pears

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International Journal of Agricultural and Biological Engineering 2024年第1期17卷 261-266页

作者： yang Liu Yurong Tang hong Zhang Hao Niu Haipeng lan College of Mechanical and Electrical Engineering Tarim UniversityAlaer 843300XinjiangChina College of Water Resources and Architectural Engineering Tarim UniversityAlaer 843300XinjiangChina

To predict the weight-loss ratio of Korla fragrant pears effectively,improve commodity value and study the variation laws of the weight-loss ratio of damaged fragrant pears during storage,this study predicted the weight-loss ratio of fragrant pears by utilizing the generalized regression neural network(GRNN),support vector regression(SVR),partial least squares regression(PLSR)and error back propagation neural network(BPNN).The prediction performances of GRNN,SVR,PLSR and BPNN models were compared comprehensively,and the optimal model was *** addition,the optimal prediction model was *** results show that weight-loss ratio of fragrant pears increases gradually with the extension of storage *** storage,the weight-loss ratio of fragrant pears is positively related to the degree of *** trained GRNN,SVR,PLSR and BPNN models can be used to predict the weight-loss ratio of fragrant *** BPNN model is the most accurate in predicting the weight-loss ratio of damaged fragrant pears(R^(2)=0.9929;RMSE=0.2138).It has also been proved to have good predictive effect in production practice(R^(2)=0.9377,RMSE=0.7138).The research findings can provide references to predict the delivery quality and time of delivery of Korla fragrant pears.

关键词： Korla fragrant pears weight-loss ratio damages storage time

2:17-type SmCo permanent magnets with controllable remanence temperature coefficients via substitution of heavy rare earth elements

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Rare Metals 2024年第8期43卷 3990-3996页

作者： Jia-Yi Huang Shu-lan Zuo Qi Zhang hong-yang Dai Lei yang Jing-Hua Liu Cheng-Bao Jiang Key Laboratory of Aerospace Materials and Performance (Ministry of Education) School of Materials Science and EngineeringBeihang University

Permanent magnets that can maintain a constant magnetic flux over a wide temperature range are highly desirable in certain applications such as precision instruments.2:17-type SmCo permanent magnets are promising for such instruments owing to their excellent high-temperature magnetic properties that can be further manipulated byadding heavy rare earth elements (HREs).

关键词： Rare earths

Interaction between granulation and small-scale magnetic flux observed by Hinode

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Research in Astronomy and Astrophysics 2009年第8期9卷 921-932页

作者： Jun Zhang Shu-hong yang Chun-lan Jin Key Laboratory of Solar Activity National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

With the polarimetric observations obtained by the Spectro-Polarimeter on board Hinode, we study the relationship between granular development and magnetic field evolution in the quiet Sun. Six typical cases are displayed to exhibit interaction between granules and magnetic elements, and we have obtained the following results. （1） A granule develops centrosymmetrically when no magnetic flux emerges within the granular cell. （2） A granule develops and splits noncentrosymmetrically while flux emerges at an outer part of the granular cell. （3） Magnetic flux emergence in a cluster of mixed polarities is detected at the position of a granule as soon as the granule breaks up. （4） A dipole emerges accompanied by the development of a granule, and the two elements of the dipole are rooted in the adjacent intergranular lanes and face each other across the granule. Advected by the horizontal granular motion, the positive element of the dipole then cancels with the pre-existing negative flux. （5） Flux cancellation also takes place between a positive element, which is advected by granular flow, and its surrounding negative flux. （6） While magnetic flux cancellation takes place in a granular cell, the granule shrinks and then disappears. （7） Horizontal magnetic fields are enhanced at the places where dipoles emerge and where opposite polarities cancel each other, but only the horizontal fields between the dipolar elements point in an orderly way from the positive elements to the negative ones. Our results reveal that granules and small-scale magnetic fluxes influence each other. Granular flow advects magnetic flux, and magnetic flux evolution suppresses granular development. There exist extremely large Doppler blue-shifts at the site of one canceling magnetic element. This phenomenon may be caused by the upward flow produced by magnetic reconnection below the photosphere.

关键词： Sun granulation -- Sun magnetic fields -- Sun photosphere-- techniques polarimetric

Recent progress in photocatalytic NAD(P)H regeneration for photocatalytic-enzymatic-coupling system

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Frontiers of Chemical Science and Engineering 2024年第4期18卷 1-24页

作者： Wei lan Maodi Wang Huicong Dai Qihua yang Key Laboratory of the Ministry of Education for Advanced Catalysis Materials Zhejiang Key Laboratory for Reactive Chemistry on Solid SurfacesInstitute of Physical ChemistryZhejiang Normal UniversityJinhua 321004China

The enzymatic redox reactions in natural photosynthesis rely much on the participation of cofactors,with reduced nicotinamide adenine dinucleotide/nicotinamide adenine dinucleotide phosphate(NADH/NADPH)or their oxidized form(NAD+/NADP+)as an important redox *** photocatalytic regeneration of expensive and unstable NADH/NADPH in vitro is an important process in enzymatic reduction and has attracted much research *** different types of photocatalysts have been developed for photocatalytic NADH/NADPH regeneration,the efficiency is still relatively *** elucidate the key factors affecting the performance of photocatalytic NADH/NADPH regeneration is helpful to rationally design the photocatalyst and improve the photocatalytic *** this paper,we overview the recent progress in photocatalytic NADH/NADPH regeneration with the focus on the strategies to improve the visible light adsorption,the charge separation and migration efficiency,as well as the surface reaction,which jointly determine the overall photocatalytic regeneration *** potential development of photocatalytic NADH/NADPH regeneration and photocatalyticenzymatic-coupling system is prospected finally.

关键词： photocatalytic-enzymatic coupling NAD(P)H regeneration photocatalysis efficiency

Bioinspired supramolecular macrocycle hybrid membranes with enhanced proton conductivity

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Nano Research 2024年第2期17卷 797-805页

作者： Pengfei yang Linlin Xu Panagiotis Trogadas Marc-Olivier Coppens yang lan Centre for Nature Inspired Engineering Department of Chemical EngineeringUniversity College LondonLondon WC1E 7JEUK

Enhancing the proton conductivity of proton exchange membranes(PEMs)is essential to expand the applications of proton exchange membrane fuel cells(PEMFCs).Inspired by the proton conduction mechanism of bacteriorhodopsin,cucurbit[n]urils(CB[n],where n is the number of glycoluril units,n=6,7,or 8)are introduced into sulfonated poly(ether ether ketone)(SPEEK)matrix to fabricate hybrid PEMs,employing a nature-inspired chemical engineering(NICE)*** carbonyl groups of CB[n]act as proton-conducting sites,while the host–guest interaction between CB[n]and water molecules offers extra protonconducting ***,the molecular size of CB[n]aids in their dispersion within the SPEEK matrix,effectively bridging the unconnected proton-conducting sulfonic group domains within the SPEEK ***,all hybrid membranes exhibit significantly enhanced proton ***,the SPEEK membrane incorporating 1 wt.%CB[8](CB[8]/SPEEK-1%)demonstrates the highest proton conductivity of 198.0 mS·cm^(−1) at 60°C and 100%relative humidity(RH),which is 228%greater than that of the pure SPEEK membrane under the same ***,hybrid membranes exhibit superior fuel cell *** CB[8]/SPEEK-1%membrane achieves a maximum power density of 214 mW·cm^(−2),representing a 140%improvement over the pure SPEEK membrane(89 mW·cm^(−2))at 50°C and 100%*** findings serve as a foundation for constructing continuous proton-conducting pathways within membranes by utilizing supramolecular macrocycles as fuel cell electrolytes and in other applications.

关键词： supramolecular macrocycle proton conductivity cucurbit[n]uril proton exchange membrane fuel cell

Cross section determination of^(27)Al(n,2n)^(26)Al reaction induced by 14-MeV neutrons uniting with D-T neutron activation and AMS techniques

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Nuclear Science and Techniques 2024年第6期35卷 78-89页

作者： Xian-Lin yang Chang-Lin lan Yu-Ting Wei Yi Zhang Gong Jiang Bo Xie Yu Liu hong-Tao Shen Xiao-Jun Sun School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China MOE Frontiers Science Center for Rare Isotopes Lanzhou UniversityLanzhou 730000China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China Guangxi Key Laboratory of Nuclear Physics and Nuclear Technology Guangxi Normal UniversityGuilin 541004China

Aluminum is the primary structural material in nuclear engineering,and its cross section induced by 14-MeV neutrons is of great *** address the issue of insufficient accuracy for the^(27)Al(n,2n)^(26)Al reaction cross section,the activation method and accelerator mass spectrometry(AMS)technique were used to determine the^(27)Al(n,2n)^(26)Al cross section,which could be used as a D-T plasma ion temperature monitor in fusion *** the China Academy of Engineering Physics,neutron activation was performed using a K-400 neutron generator produced by the T(d,n)4He ***^(26)Al∕^(27)Al isotope ratios were measured using the newly installed GYIG 1 MV AMS at the Institute of Geochemistry,Chinese Academy of *** neutron flux was monitored by measuring the activity of 92mNb produced by the 93Nb(n,2n)92mNb *** measured results were compared with available data in the experimental nuclear reaction database,and the measured values showed a reasonable degree of consistency with partially available literature *** newly acquired cross-sectional data at 12 neutron energy points through systematic measurements clarified the divergence,which has two different growth trends from the existing experimental *** obtained results are also compared with the corresponding evaluated database,and the newly calculated excitation functions with TALYS−1.95 and EMPIRE−3.2 codes,the agreement with CENDL−3.2,TENDL-2021 and EMPIRE−3.2 results are generally acceptable.A substantial improvement in the knowledge of the^(27)Al(n,2n)^(26)Al reaction excitation function was obtained in the present work,which will lay the foundation for the diagnosis of the fusion ion temperature,testing of the nuclear physics model,evaluation of nuclear data,etc.

关键词： 14-MeV neutron ^(27)Al(n,2n)^(26)Al Cross section AMS

A Special Editor’s Issue on Magnesium Matrix Composites

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 389-390页

作者： Xianhua Chen hong yang College of Materials Science and Engineering Chongqing UniversityChongqing 400045China National Engineering Research Center for Mg Alloys Chongqing UniversityChongqing 400045China

Magnesium(Mg)alloys offer distinct advantages as one of the lightest structural *** remarkable weight advantages,being 35%lighter than aluminum alloy and a striking 78%lighter than steel,make them a focal point for research in automotive and aerospace *** emphasis stems from the overarching goal of reducing energy costs and enhancing overall performance[1,2].

关键词： alloy steel alloys

Parametric“non-nested”discriminants for multiplicities of univariate polynomials

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Science China Mathematics 2024年第8期67卷 1911-1932页

作者： Hoon hong Jing yang Department of Mathematics North Carolina State UniversityRaleighNC 27695USA SMS-HCIC-School of Mathematics and Physics Center for Applied Mathematics of GuangxiGuangxi Minzu UniversityNanning 530006China

We consider the problem of complex root classification,i.e.,finding the conditions on the coefficients of a univariate polynomial for all possible multiplicity structures on its complex *** is well known that such conditions can be written as conjunctions of several polynomial equalities and one inequality in the *** polynomials in the coefficients are called discriminants for *** is also known that discriminants can be obtained using repeated parametric greatest common *** resulting discriminants are usually nested determinants,i.e.,determinants of matrices whose entries are determinants,and so *** this paper,we give a new type of discriminant that is not based on repeated greatest common *** new discriminants are simpler in the sense that they are non-nested determinants and have smaller maximum degrees.

关键词： parametric polynomial complex roots discriminant multiplicity resultant

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