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Cenozoic reactivation along the Late Triassic Ganzi-Litang suture,eastern Tibetan Plateau

Geoscience Frontiers 2020年第3期11卷 1069-1080页

作者： W.T.Jackson Jr. d.M.Robinson A.L.Weislogel x.Jian department of Earth Sciences University of South AlabamaMobileAL36688USA department of Geological Sciences and Center for Sedimentary Basin Studies The University of AlabamaTuscaloosaAL35487USA department of Geography and Geology West Virginia UniversityMorgantownWV26506USA State Key Laboratory of marine Environmental Science College of Ocean and Earth SciencesXiamen UniversityXiamen 361102China

The spatial-temporal development of Cenozoic reactivation along Mesozoic suture zones in the Tibetan Plateau are first-order parameters needed for assessing models of plateau *** Ganzi-Litang suture,in the eastern Tibetan Plateau,developed in the Late Triassic because of subduction and closure along the eastern branch of the Paleo-Tethys *** the city of Litang,the Ganzi-Litang suture is defined by a melange sequence with faultbound,synorogenic nonmarine strata along the western and eastern flanks,suggesting post-Triassic structural *** present detrital zircon U-Pb geochronology and field data to determine the timing and style of reactivation along the Ganzi-Litang suture,as well as sedimentary provenance of nonmarine strata.A reverse fault placing melange rock on top of nonmarine strata along the eastern flank of the Ganzi-Litang suture indicates a contractional deformational regime during *** clast counts indicate a local sediment source of recycled Ganzi-Litang suture and Yidun terrane *** zircons indicate a localized provenance consisting of recycled material from Triassic Yidun Arc plutons and Triassic Yidun Group turbidite rock.A weighted mean average of Cenozoic zircon grains(n=10) establishes a maximum depositional age of41.5 ± 1.2 ma for nonmarine strata in the Ganzi-Litang *** interpret the maximum depositional age of the nonmarine strata to represent the upper-limit for structural reactivation along the Ganzi-Litang suture while undeformed Neogene strata in the suture zone represent the lower-limit;thereby bracketing structural reactivation from ca.42-25 *** results provide enhanced spatial-temporal resolution for Cenozoic deformation in the eastern Tibetan Plateau.

关键词： Nonmarine strata Yidun terrane Tibetan plateau Zircon Suture zone Reactivation

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Unified Limits and Large deviation Principles forβ-Laguerre Ensembles in Global Regime

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Acta mathematica Sinica,English Series 2023年第7期39卷 1271-1288页

作者： Yu Tao ma School of mathematical Sciences&Laboratory of mathematics and Complex Systems of Ministry of Education Beijing Normal UniversityBeijing 100875China

Let(λ_(1),...,λ_(n)) be β-Laguerre ensembles with parametersβ,p,n and μ_(n):=1/n∑^(n)_(i=1)δ_(xi) with for 1≤i≤*** this paper,asβvaries and satisfies lim_(n→∞)log n/βn=0,we offer a modified marchenko-Pastur,law or semicircle law as the weak limits for the sequence μ_(n) when lim_(n→∞)n/p=γ∈(0,1]or lim_(n→∞)n/p=0,*** recovers some well-known ***,we give a full large deviation principle of μ_(n) with speed βn^(2) and good rate function I_(γ) under the same condition to characterize the speed of the *** minimizer of I_(γ) is a modified marchenko-Pastur law forγ∈(0,1]and the semicircle law forγ=0.

关键词： β-Laguerre ensemble large deviation principle empirical measure semicircular law marchenko–Pastur law

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Microstructure and Mechanical Properties of Nanocrystalline Tungsten Thin Films

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Journal of materials Science & Technology 2010年第1期26卷 87-92页

作者： H.L. Sun, Z.x. Song, d.G. Guo, F. ma and K.W. xu State Key Laboratory for Mechanical Behavior of materials, School of materials Science and Engineering, xi an Jiaotong University, xi’an 710049, China [a] State Key Laboratory for Mechanical Behavior of materials School of materials Science and Engineering xi'an Jiaotong University xi'an 710049 China

Tungsten （W） thin films were prepared by magnetron sputtering onto Si （100） substrates. Their microstructures were characterized by x-ray diffraction （xRd）, field emission scanning electron microscopy （FE-SEM） and transmission electron microscopy （TEM）. The hardness and modulus were evaluated by nanoindentation. It is found that a 30 nm Cr sticking layer induces structure changes of deposited W film from β-W to α-W structure. In addition, remarkable hardness enhancement both for the deposited and annealed W films, were compared with that of bulk coarse-grained W, although their nanoindentation modulus is very close to that of corresponding bulk W. The intrinsic reasons that lead to structure changes and super hardness are discussed.

关键词： Tungsten film Microstructure Nanoindentation Hardness Modulus

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Structural design and dynamic Characteristics of Overloaded Horizontal Servo Cylinder for Resisting dynamic Partial Load

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Chinese Journal of Mechanical Engineering 2019年第1期32卷 103-112页

作者： Linan ma Qingxue Huang Lifeng ma Qiangjun ma Wenze Zhang Heyong Han Collaboration Innovation Center of Taiyuan Heavy machinery Equipment Taiyuan University of Science and Technology Taiyuan University of Technology

When an output curve force is applied to a horizontal servo cylinder with a heavy load, the piston rod bears a dynamic partial load based on the installation and load characteristics, which significantly a ects the frequency response and control accuracy of the servo cylinder. Based on this partial load, increased friction can lead to cylinder bore scu ng, leakage, lack of output power, or even system failure. In this paper, a novel asymmetric static-pressure support structure is proposed based on the principle of hydrostatic support. The radial component force of a dynamic partial load is balanced by cooperation between the support oil cushion of the variable hydraulic pressure support structure, oil cushion of the supportive force, and the damper. Adaptive control of the servo cylinder piston rod, guide sleeve, and piston, as well as the cylinder oil film friction between lubricated surfaces is achieved. In this paper, theoretical design and analysis of the traditional hydrostatic bearing structure and novel structure are presented. A hydraulic dynamic shear scissor is used as a research target to derive a structural dynamic model. Comparative simulations are performed using matlab Simulink. Additionally, flow field analysis of the novel structure is performed, which verifies the rationality and feasibility of the proposed structure and system.

关键词： dynamic partial load Servo cylinder Asymmetrical static-pressure support structure Bearing characteristics

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ExTRUSION dIE CAE OF THE STEEL REINFORCEd PLASTIC PIPE

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Acta Metallurgica Sinica(English Letters) 2004年第3期17卷 303-306页

作者： W.Q.ma H.Y.Sun d.C.Kang K.d.Zhao Harbin Institute of Technology Harbin 150001 China Daqing Oilfield Postdoctoral Workstation Daqing 163453 ChinaHarbin University of Science and Technology Harbin 150080 China Daqing Oilfield Postdoctoral Workstation Daqing 163453 ChinaHarbin Institute of Technology Harbin 150001 ChinaHarbin Institute of Technology Harbin 150001 China

The steel reinforced plastic pipe is a new kind of pressure pipe. It is made up with steelwires and plastic. Because reinforced skeleton of the steel wire increase the complexityof plastic flow during the extrusion phase, the traditional design criteria of extrusiondie is not suitable. The study on extrusion die of the kind of pipe is very importantstep in produce development. Using finite element (FE) method in this paper, theflow rule of molten plastic inside the die has been predicted and a groap of optimalstructural parameters was obtained. These results are helpful for reducing the designcycle and improve the quality of the final product.

关键词： steel reinforced plastic pipe extrusion die computer aid engineering(CAE)

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The dimension split element-free Galerkin method for three-dimensional potential problems

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Acta Mechanica Sinica 2018年第3期34卷 462-474页

作者： Z.J.Meng H.Cheng L.d.ma Y.M.Cheng Shanghai Institute of Applied mathematics and Mechanics Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai University School of Applied Science Taiyuan University of Science and Technology department of Civil Engineering Shanghai University School of materials Science and Engineering Taiyuan University of Science and Technology

This paper presents the dimension split element-free Galerkin （dSEFG） method for three-dimensional potential problems, and the corresponding formulae are obtained. The main idea of the dSEFG method is that a three-dimensional potential problem can be transformed into a series of two-dimensional problems. For these two-dimensional problems, the improved moving least-squares （IMLS） approximation is applied to construct the shape function, which uses an orthogonal function system with a weight function as the basis functions. The Galerkin weak form is applied to obtain a discretized system equation, and the penalty method is employed to impose the essential boundary condition. The finite difference method is selected in the splitting direction. For the purposes of demonstration, some selected numerical examples are solved using the dSEFG method. The convergence study and error analysis of the dSEFG method are presented. The numerical examples show that the dSEFG method has greater computational precision and computational efficiency than the IEFG method.

关键词： dimension split method Improved moving least-squares (IMLS) approximation Improved element-free Galerkin (IEFG) method Finite difference method (FdM) dimension split element-free Galerkin (dSEFG) method Potential problem

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Pesticide-induced photoluminescence quenching of ultra-small Eu3+-activated phosphate and vanadate nanoparticles

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Journal of materials Science & Technology 2020年第3期38卷 197-204页

作者： Jovana Perisa Zeljka Antic Chong-Geng ma Jelena Papan dragana Jovanovic Miroslav d.dramicanin Vinca Institute of Nuclear Sciences University of BelgradeP.O.Box 52211001 BelgradeSerbia College of Sciences Chongqing University of Posts and TelecommunicationsChongqing 400065China

The aim of this research was to investigate the luminescent behavior of ultra-small Eu3+-activated phosphate and vanadate nanoparticles in the presence of *** have an average diameter of approximately 2 nm with a narrow size *** monazite crystal structure of phosphate-based particles(space group P121/n1)and single tetragonal zircon-type structure of vanadate-based particles(space group of I41/amd)have been confirmed using x-ray diffraction *** synthesized Eu3+-activated colloidal nanoparticles show sharp emission peaks in the red spectral *** measurements revealed emission quenching upon addition of millimolar concentrations of following pesticides:4-Chloro-2-methyl-phenoxyacetic acid(MCPA),2,4-dichlorophenoxyacetic acid(2,4-d)and N-(phosphonomethyl)glycine(Glyphosate).In both phosphate and vanadate-based colloidal nanoparticles luminescence quenching is more evident in the presence of 2,4-d pesticide with the lowest limit of detection(0.7μM)obtained for phosphate-based nanoparticles.

关键词： Phosphate/vanadate based colloidal nanoparticles Eu3+ Emission quenching Pesticide

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Evolution of the Microstructure and Strength in the Nugget Zone of Friction Stir Welded SiCp/Al-Cu-Mg Composite

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Journal of materials Science & Technology 2014年第1期30卷 54-60页

作者： d.Wang B.L.xiao Q.Z.Wang Z.Y.ma Shenyang National Laboratory for materials Science Institute of Metal ResearchChinese Academy of Sciences University of Science and Technology of China

A 6 mm-thick SiCp/2009AI composite plate was successfully joined by friction stir welding （FSW） using an ultrahard material tool to investigate the evolution of the microstructure and the strength in the nugget zone （NZ）. While some SiC particles were broken up during FSW, most of them rotated in the matrix. Large compound particles on the interfaces were broken off during FSW, whereas the amorphous layer and small compound particles remained on the interfaces. The dynamically recrystallized AI grains nucleated on the surface of fractured SiC particles during FSW, forming nano-sized grains around the SiC particles. The yield strength of the NZ decreased slightly due to the variation in the size, shape, and distribution of the SiC particles. The clean interfaces were beneficial to the load transfer between SiC particles and AI matrix and then increased the ultimate tensile strength of the NZ.

关键词： Metal-matrix composites Friction stir welding Microstructure Mechanical properties

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Effect of Particle Size on Mechanical Properties and Fracture Behaviors of Age-Hardening SiC/Al–Zn–Mg–Cu Composites

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Acta Metallurgica Sinica(English Letters) 2021年第10期34卷 1447-1459页

作者： Guonan ma dong Wang Bolv xiao Zongyi ma Institute of Metal Research Chinese Academy of SciencesShenyang 110016China School of materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China

15 vol.% SiC/Al-6.5Zn-2.8 Mg-1.7 Cu(wt%) composites with varying particle sizes(3.5, 7.0, 14 and 20 μm), i.e., C-3.5, C-7.0, C-14, and C-20, respectively, were fabricated by powder metallurgy(PM) method and subjected to microstructural examination. The effect of particle size on mechanical properties and fracture behaviors of the T6-treated composites was revealed and analyzed in detail. Element distribution and precipitates variations in the composites with varying particle sizes were emphatically considered. Results indicated that both tensile strength and plasticity of the T6-treated composites increased first and then decreased with particle size decreasing. The C-7.0 composite simultaneously exhibited the highest ultimate tensile strength(UTS) of 686 MPa and best elongation(El.) of 3.1%. The smaller-sized SiC particle would introduce more oxide impurities, which would react with the alloying element in the matrix to cause Mg segregation and depletion. According to strengthening mechanism analysis, the weakening of precipitation strengthening in the T6-treated C-3.5 composite was the main cause of the lower tensile strength. Additionally, the larger SiC particle, the more likely to fracture, especially in the composites with high yield strength. For the T6-treated C-20 composites, more than 75% SiC particles were broken up, resulting in the lowest plasticity. As decreasing particle size, the fracture behaviors of the T6-treated composites would change from particle fracture to matrix alloy fracture gradually.

关键词： Metal matrix composites Mechanical properties Particle size Fracture behaviors Strengthening mechanisms

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Morphology and phylogeny of root-endophytic fungus Periconia igniaria

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Studies in Fungi 2019年第1期4卷 274-281页

作者： d’Souza ma Rana S Singh SK department of Botany St.Xavier’s CollegeMapusaGoa-403507India National Fungal Culture Collection of India Biodiversity and Palaeobiology GroupMACS'Agharkar Research InstituteGG Agarkar Road411004 PuneIndia

Periconia igniaria,isolated as an endophytic fungus from roots of Cheilocostus speciosus from Calangute,Bardez,Goa,India was described in this *** identity of the endophytic isolate was based on asexual-morphs,cultural characteristics and phylogenetic analyses of internal transcribed spacer rdNA sequence *** our knowledge,this is the first report of this taxon as root endophyte of Cheilocostus speciosus from Western Ghats forests,Goa,India.

关键词： Cheilocostus speciosus Goa Taxonomy Western Ghats

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