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Evolution of microstructure and texture in copper during repetitive extrusion-upsetting and subsequent annealing

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journal of Materials Science & Technology 2017年第7期33卷 690-697页

作者： Q.Chen D.y.Shu j.lin y.Wu X.S.Xia S.H.Huang Z.D.Zhao O.V.Mishin G.L.Wu State Key Laboratory of Mechanical Transmission Chongqing University Chongqing 400044 China

The evolution of the microstructure and texture in copper has been studied during repetitive extrusionupsetting（REU） to a total von Mises strain of 4.7 and during subsequent annealing at different temperatures. It is found that the texture is significantly altered by each deformation pass. A duplex 001 ＋ 111 fiber texture with an increased 111 component is observed after each extrusion pass,whereas the 110 fiber component dominates the texture after each upsetting pass. During REU, the microstructure is refined by deformation-induced boundaries. The average cell size after a total strain of 4.7 is measured to be ~0.3 μm. This refined microstructure is unstable at room temperature as is evident from the presence of a small number of recrystallized grains in the deformed matrix. Pronounced recrystallization took place during annealing at 200？C for 1 h with recrystallized grains developing predominantly in high misorientation regions. At 350？C the microstructure is fully recrystallized with an average grain size of only 2.3 μm and a very weak crystallographic texture. This REU-processed and subsequently annealed material is considered to be potentially suitable for using as a material for sputtering targets.

关键词： Severe plastic deformation Repetitive extrusion-upsetting Copper Deformation microstructure Texture Annealing

Data-driven Static Equivalence with Physics-informed Koopman Operators

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CSEE journal of Power and Energy Systems 2024年第1期10卷 432-438页

作者： Wei lin Changhong Zhao Maosheng Gao C.y.Chung Department of Electrical Engineering The Hong Kong Polytechnic UniversityHong Kong SARChina Department of Information Engineering The Chinese University of Hong KongHong Kong SARChina School of Electrical Engineering Chongqing UniversityChongqing 400044China

With deployment of measurement units,fitting static equivalent models of distribution networks(DNs)by linear regression has been recognized as an effective method in power flow analysis of a transmission *** volatility of measurements caused by variable distributed renewable energy sources makes it more difficult to accurately fit such equivalent *** tackle this challenge,this letter proposes a novel data-driven method to improve equivalency accuracy of DNs with distributed energy *** letter provides a new perspective that an equivalent model can be regarded as a mapping from internal conditions and border voltages to border power *** mapping can be established through 1)Koopman operator theory,and 2)physical features of power flow equations at the root node of a *** of the proposed method is demonstrated on the IEEE 33-bus and IEEE 136-bus test systems connected to a 661-bus utility system.

关键词： Data-driven distribution network Koopman operator theory static equivalent model

The quasi-Gramian solution of a non-commutative extension of the higher-order nonlinear Schr?dinger equation

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Communications in Theoretical Physics 2024年第3期76卷 51-61页

作者： H W A Riaz j lin Department of Physics Zhejiang Normal UniversityJinhua 321004China

The nonlinear Schr?dinger(NLS)equation,which incorporates higher-order dispersive terms,is widely employed in the theoretical analysis of various physical *** this study,we explore the non-commutative extension of the higher-order NLS *** treat real or complex-valued functions,such as g_(1)=g_(1)(x,t)and g_(2)=g_(2)(x,t)as non-commutative,and employ the Lax pair associated with the evolution equation,as in the commutation *** derive the quasi-Gramian solution of the system by employing a binary Darboux *** soliton solutions are presented explicitly within the framework of *** visually understand the dynamics and solutions in the given example,we also provide simulations illustrating the associated ***,the solution can be used to study the stability of plane waves and to understand the generation of periodic patterns within the context of modulational instability.

关键词： integrable systems Darboux transformation solitons

Creep-induced redistribution of alloying elements in CZ1 zirconium alloys

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journal of Materials Science & Technology 2024年第6期173卷 31-44页

作者： W.T.lin Q.y.Lv D.jiao L.B.Zhang j.Tan G.Sha j.Hu China Nuclear Power Technology Research Institute Shenzhen 518026China School of Material Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China

Introducing minor alloying elements is an effective strategy to improve the corrosion and mechanical properties of zirconium alloys for nuclear *** in-reactor service,external environment and stress can affect the distribution of alloying elements,substantially changing the degradation process of zirconium *** date,there is a lack of in-depth understanding of the interaction between creep and microchemistry ***,we conducted systematic transmission electron microscopy(TEM)and atom probe tomography(APT)investigations to address creep-induced redistribution of alloying elements in CZ1(Zr-Sn-Nb-Fe-Cr-Cu)zirconium alloy with different initial ***,Fe,Sn,and Cu are found to co-segregate at grain *** higher the intermediate annealing temperature,the larger the Gibbsian interfacial excesses of solute elements *** further demonstrate that creep can reduce the excess value of Fe at grain boundaries due to the coarsening of Zr-Fe-Cr second phase particles via grain boundary and dislocation pipe *** the same time,the excess value of Sn is increased by diffusing from the matrix to grain ***,Cu as a minor element in the concentration range of 0.05-0.3 wt.%is found to segregate at dislocations to form the Cottrell atmosphere and develop Cu-rich nanoclusters for suppressing dislocation *** new understanding of the segregation and clustering of minor alloying elements provides guidance for developing zirconium alloys with enhanced creep resistance.

关键词： Zirconium alloy Thermal creep Grain boundary segregation Dislocation segregation Cu-rich nanoclusters

Temperature-Dependent Raman Scattering of Phonon Modes and Defect Modes in GaN and p-Type GaN Films

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journal of Semiconductors 2005年第4期26卷 635-640页

作者：王瑞敏陈光德 lin j y jang H X 西安交通大学理学院西安710049 Department of Physics Kansas State University

Raman spectra of undoped GaN and Mg-doped GaN films grown by metal-organic chemical-vapor deposition on sapphire are investigated between 78 and 573K.A peak at 247cm -1 is observed in both Raman spectra of GaN and Mg-doped *** is suggested that the defect-induced scattering is origin of the *** electronic Raman scattering mechanism and Mg-related local vibrational mode are ***,the differences of E_2 and A_1(LO) modes in two samples are also *** stress relaxation is observed in Mg-doped GaN.

关键词： GaN p-type GaN ,Raman scattering defect modes

Construction of 2D/2D Ti_(3)C_(2)T_(x)MXene/CdS heterojunction with photothermal effect for efficient photocatalytic hydrogen production

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journal of Materials Science & Technology 2024年第4期171卷 1-9页

作者： T.y.Huang Z.yang S.y.yang Z.H.Dai y.j.Liu j.H.Liao G.y.Zhong Z.j.Xie y.P.Fang S.S.Zhang Key Laboratory for Biobased Materials and Energy of Ministry of Education Guangdong Laboratory for Lingnan Modern AgricultureCollege of Materials and EnergySouth China Agricultural UniversityGuangzhou 510643China School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China School of Chemical Engineering and Energy Technology Guangdong Provincial Key Laboratory of Distributed Energy SystemsDongguan University of TechnologyDongguan 523808China

The insensitivity of semiconductors to visible and infrared light is a key constraint on the utilization of light energy in photocatalytic *** photocatalysts with full-spectrum absorption through surface engineering is an effective approach to fully harnessing light energy in semiconductor ***,a novel stable Ti_(3)C_(2)T_(x)MXene/CdS heterojunction catalyst is obtained by in-situ epitaxial growth of two-dimensional(2D)CdS nanosheets on 2D MXene interface via a solvothermal *** exceptional light absorption properties of MXene confer outstanding full-spectrum driven photocat-alytic hydrogen evolution capability upon the heterogeneous *** unique 2D/2D structure effectively mitigated the recombination of photogenerated carriers,enhancing the photocatalytic performance of the ***,the composite catalyst exhibits a significantly higher surface temperature of 80.4℃under visible light irradiation at an intensity of 0.1 W/cm^(2),which is 1.84 times higher than that of *** irradiation of visible and near infrared light,the composite catalyst with photothermal ef-fect demonstrates a remarkable hydrogen evolution rate of 65.4 mmol g^(-1)h^(-1),which is 7.2 times higher than that of CdS *** study introduces a novel approach for constructing full-spectrum absorption catalysts and expands the application of the photothermal effect in photocatalytic hydrogen evolution research.

关键词： Two-dimensional structure Heterostructure Photothermal effect Photocatalyst Hydrogen evolution

Effect of Cooking Method and Storage on the Quality of Minced Pork

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journal of Agricultural Science and Technology(A) 2011年第8期1卷 1249-1256页

作者： H.S. lin j.y. Lee B.C. Ke Department of Applied Science of Living Chinese Culture University Taipei Taiwan

Minced pork paste was mixed with cooked rice and noodle resulted in very popular traditional gourmet meal in Taiwan. The 100 ℃, 4 h was normally cooking condition for commercial business. However, the pressure cooker with higher cooking temperature （106 ℃, 116 ℃ and 121 ℃） and different cooking time were under studied in order to improving efficiency, quality and even cost down. The samples of neck pork substitute, cooking at 106℃, 100 rain; 116℃, 75 min; 121 ℃, 45 min with different pressure were perfomed the result as well as traditional 20% fat in ordinary formulation and cooking at 100℃ for 4 h. During storage, the products were taste acceptable for 4 weeks at 4 ℃, 4 months at - 18 ℃ and better than 1 day at 25 ℃ storage.

关键词： Minced pork paste sensory trait AV (Acid value) POV (peroxide value)

Supposition of graphene stacks to estimate the contact resistance and conductivity of nanocomposites

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Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 663-676页

作者： y.ZARE M.T.MUNIR G.j.WENG K.y.RHEE Biomaterials and Tissue Engineering Research Group Department of Interdisciplinary TechnologiesBreast Cancer Research CenterMotamed Cancer InstituteTehran ***Iran College of Engineering and Technology American University of the Middle EastEgaila 54200Kuwait Department of Mechanical and Aerospace Engineering Rutgers UniversityNew BrunswickNJ 08903U.S.A. Department of Mechanical Engineering(BK21 Four) College of EngineeringKyung Hee UniversityYongin 446701Republic of Korea

In this study,the effects of stacked nanosheets and the surrounding interphase zone on the resistance of the contact region between nanosheets and the tunneling conductivity of samples are evaluated with developed equations superior to those previously *** contact resistance and nanocomposite conductivity are modeled by several influencing factors,including stack properties,interphase depth,tunneling size,and contact *** developed model's accuracy is verified through numerous experimental *** further validate the models and establish correlations between parameters,the effects of all the variables on contact resistance and nanocomposite conductivity are ***,the contact resistance is primarily dependent on the polymer tunnel resistivity,contact area,and tunneling *** dimensions of the graphene nanosheets significantly influence the conductivity,which ranges from 0 S/m to90 S/*** increased number of nanosheets in stacks and a larger gap between them enhance the nanocomposite's ***,the thicker interphase and smaller tunneling size can lead to higher sample conductivity due to their optimistic effects on the percolation threshold and network efficacy.

关键词： graphene polymer composite stacked nanosheet tunneling conductivity contact resistance interphase

MOCVD生长的GaN和GaN∶Mg薄膜的拉曼散射

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发光学报 2005年第2期26卷 229-232页

作者：王瑞敏陈光德 lin j y jIANG H X 西安交通大学理学院 Department of Physics Kansas State University Manhattan Kansas 66506 USA

通过显微拉曼散射对用金属有机化学气相沉积(MOCVD)法在Al2O3 衬底上生长的六方相GaN和掺Mg的p型GaN薄膜进行了研究。在两个样品的拉曼散射谱中同时观察到位于640, 660cm-1附近的两个峰,640cm-1的峰归因于布里渊区边界(L点)最高声学声... 详细信息

通过显微拉曼散射对用金属有机化学气相沉积(MOCVD)法在Al2O3 衬底上生长的六方相GaN和掺Mg的p型GaN薄膜进行了研究。在两个样品的拉曼散射谱中同时观察到位于640, 660cm-1附近的两个峰,640cm-1的峰归因于布里渊区边界(L点)最高声学声子的二倍频,而660cm-1的峰为布里渊区边界的光学声子支或缺陷诱导的局域振动模。掺Mg的GaN在该处的峰型变宽是Mg诱导的缺陷引起的加宽或Mg的局域模与上述两峰叠加的结果。在掺Mg的样品中还观察到276, 376cm-1几个局域模并给予了解释。同时掺Mg的GaN中出现了应力弛豫的现象,掺Mg引起的失配位错和电子声子相互作用都有可能对E2 模的频率产生影响。

关键词：氮化镓拉曼散射应力松弛