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STABILITY EIGENFUNCTIONS OF A BOUNDARY-LAYER FLOW OVER VISCOELASTIC COMPLIANT WALL

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Journal of Hydrodynamics 2001年第4期13卷 48-54页

作者： Zhao, han-zhong Dept. of Mech. Huazhong Univ. of Sci. and Technol. Wuhan 430074 China

The eigenfunctions in a stability problem of boundary-layer flow over a viscoelastic compliant wall were studied. Two categories of modes, TSI and CIFI, exist in the eigenvalue solutions. The eigenfunctions of flow-based TSI were investigated together with those in the flow over rigid wall, whereas the eigenfunctions of wall-based CIFI were compared with the wall functions in an individual wall without fluid constraint. The physical characteristics of the eigenmodes were discussed based on their eigenfunctions.

关键词： Eigenvalues and eigenfunctions Naval vessels Stability Viscoelasticity

Impurity Effect on Wear Resistance of Ultrafine-Grained Copper

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Journal of Materials Science & Technology 2012年第6期28卷 481-487页

作者： Bin Yao zhong han Ke Lu Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

The wear properties of ultrafine-grained （UFG） Cu samples of different purities were investigated in comparison with the coarse-grained （CG） Cu. The UFG Cu samples, prepared by means of plastic deformation via quasi- static compression, exhibit an enhanced wear resistance relative to the CG Cu samples. For both the UFG and the CG Cu samples, wear volumes increase at higher purities. A steady state worn subsurface structure was formed in each sample after sliding for 60 rain, consisting of a heavily deformed nanostructured mixing layer （NML） on top of a continuous dynamic recrystallization （DRX） layer. A pronounced correlation is identified that wear volume increases monotonically with an increasing grain size of the DRX layer. The impurity level of the Cu samples has an obvious influence on the DRX grain sizes, which in turn determines the wear resistance of the Cu samples.

关键词： Ultrafine grained copper Wear resistance Impurity Subsurface microstructure Dynamic recrystallization

Friction and Wear Behaviors of Nanostructured Metals

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Journal of Materials Science & Technology 2008年第4期24卷 483-494页

作者： zhong han Yusheng ZhanG Ke LU Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang110016 China

Nanostructured （ns） materials, i.e., polycrystalline materials with grain sizes in the nanometer regime （typically below 100 nm）, have drawn considerable attention in the past decades due to their unique properties such as high strength and hardness. Wear resistance of ns materials, one of the most important properties for engineering materials, has been extensively investigated in the past decades. Obvious differences have been identified in friction and wear behaviors Between the ns materials and their corresponding coarse-grained （cg） counterparts, consistently correlating with their unique structure characteristics and mechanical properties. On the other hand, the superior tribological properties of ns materials illustrate their potential applications under contact loads. The present overview will summarize the important progresses achieved on friction and wear behaviors of ns metallic materials, including ultrafine-grained （ufg） materials in recent years. Tribological properties and effects on friction and wear behaviors of ns materials will be discussed under different wear conditions including abrasive wear, sliding wear, and fretting wear. Their correlations with mechanical properties will be analyzed. Perspectives on development of this field will be highlighted as well.

关键词： Nanostructured metals Friction Wear Mechanical properties Tribological properties

Annealing Effect on Wear Resistance of Nanostructured 316L Stainless Steel Subjected to Dynamic Plastic Deformation

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Journal of Materials Science & Technology 2012年第10期28卷 871-877页

作者： Bo Wang Bin Yao zhong han Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

Bulk nanostructured 316L austenitic stainless steel （SS） samples with nano-scale twin bundles embedded in nano-sized grains were synthesized by using dynamic plastic deformation （DPD）. Subsequent thermal an-nealing of the as-DPD sample leads to a single austenitic structure with static recrystallized （SRX） grains in nanostructured matrix. Oil-lubricated sliding tests of ball-on-disc type were carried out for the as-DPD and the as-annealed DPD steel samples in comparison with coarse grained （CG） steel samples. Experimental results show that the as-DPD 316L steel exhibits a little enhanced wear resistance under a load of 10 N, and nearly identical wear resistance under a load of 30 N relative to that of the CG sample. After annealing, the wear resistance roughly follows the Archard equation under a load of 10 N. However, the wear resistance increases with increasing hardness, and decreases with a further increase in hardness under a load of 30 N. The highest wear resistance can be found in the DPD sample annealed at 750 ℃ for about 20 min, which is more than 46% higher than that of the CG steel sample. This phenomenon is originated from the microstructure with an optimized combination of strength and ductility as a result of moderate plastic deformation in SRX grained regions.

关键词： Nanostructrued metals Stainless steel Wear resistance Annealing Subsurfacemicrostructure

Investigation of the level spectra of nuclei in the northeast region of doubly magic^(40)Ca with intruder orbit g_(9/2)

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Nuclear Science and Techniques 2023年第6期34卷 115-123页

作者： Jin-zhong han Shuai Xu Amir Jalili han-Kui Wang School of Physics and Telecommunication Engineering Zhoukou Normal UniversityZhoukou466000China Department of Physics Zhejiang SCI-TECH UniversityHangzhou310018China School of Physics Nankai UniversityTianjin300071China School of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai200240China

This study utilizes large-scale shell model calculations with the extended pairing and multipole–multipole force model(EPQQM)to investigate low-lying states in the nuclei of^(42)Ca,^(42)Sc,and^(42−44)*** model space in this study includes the fp shell as well as the intruder g_(9/2)orbit,which accurately reproduces the positive parity levels observed in the aforementioned nuclei and predicts high energy states with negative parity coupled with the intruder g_(9/2).The study further predicts two different configurations in^(43)Ti at around 6 MeV,specificallyπf_(7/2)^(2)νg_(9/2)andπf_(7/2)g_(9/2)νf_(7/2),both of which involve the intruder orbit g_(9/2).The levels coupled with the intruder g_(9/2)in^(44)Ti are predicted to lie between 7 and 11 *** inclusion of the intruder orbit g_(9/2)is crucial for the exploration of high energy states in the northeast region of the doubly magic nucleus^(40)Ca.

关键词： Shell model Doubly magic Level structure

Associated Production of a Neutral Top-Higgs with Top Quark Pairs at the LHC within the TC2 model

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Chinese Physics Letters 2011年第4期28卷 67-70页

作者： LI Bing-zhong han Jin-zhong College of Physics and Information Engineering Henan Normal UniversityXinxiang 453007 College of Physics and Electronic Engineering Xinyang Normal UniversityXinyang 464000

Within the context of the topcolor-assisted technicolor(TC2)model we investigate the associated production of the neutral top-higgs hto with a pair of top quarks,***→t_(t)hto at the Large Hadron Collider(LHC),which proceeds through the partonic processes q(q)→t_(t)hto and gg→t_(t)*** calculate the production rate and show the distributions of the transverse momenta of *** is found that the cross section of pp→t_(t)hot can reach a few hundred fb in the most part of the allowed parameter space and even a few tens of pb for the light *** to the large cross section of t_(t)hto production and the top-charm decay mode of h0t for mhto<2mt,the process pp→t_(t)hto can play an important role in the probe of neutral top-higgs and the test of the TC2 model.

关键词： neutral allowed quark

Applications of a Few Lie Algebras

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Acta Mathematicae Applicatae Sinica 2016年第2期32卷 289-304页

作者： Yu-feng ZhanG zhong han zhong-long ZHAO College of Sciences China University of Mining and Technology

Two isomorphic groups R2 and M are firstly constructed. Then we extend them into the differential manifold R2n and n products of the group M for which four kinds of Lie algebras are obtained. By using these Lie algebras and the Tu scheme, integrable hierarchies of evolution equations along with multi-component potential functions can be generated, whose Hamiltonian structures can be worked out by the variational identity. As application illustrations, two integrable Hamiltonian hierarchies with 4 component potential functions are obtained, respectively, some new reduced equations are followed to present. Specially remark that the integrable hierarchies obtained by taking use of the approach presented in the paper are not integrable couplings. Finally, we generalize an equation obtained in the paper to introduce a general nonlinear integrable equation with variable coefficients whose bilinear form, BEcklund transformation, Lax pair and infinite conserved laws are worked out, respectively, by taking use of the Bell polynomials.

关键词： group Lie algebra bilinear Lax pair conservation law

Carbonate Ontology and Its Application for Integrating Microfacies Data

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Journal of Earth Science 2023年第5期34卷 1328-1338页

作者： Yiwei Xu Xiumian Hu zhong han State Key Laboratory of Paleobiology and Stratigraphy Nanjing Institute of Geology and PaleontologyChinese Academy of SciencesNanjing 210008China State Key Laboratory of Mineral Deposit Research School of Earth Sciences and Engineering.Nanjing UniversityNanjing 210023China State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Institute of Sedimentary GeologyChengdu University of TechnologyChengdu 610059China

Carbonate rocks record essential information on changes in paleoclimate and paleoceanography. Abundant geological and geochemical data of carbonate rocks have been accumulated over the past decades;however, most of the data are stored in the published literature with highly unstructured forms, and are thus difficult to reuse. The ontology is a standard knowledge model for data integration, which can promote data storage and reutilization. This study proposes a carbonate ontology that represents the concepts in carbonate microfacies. The carbonate ontology constructed by the top-down process contains 215 terms of classifications and petrographic descriptions of carbonate rocks. Furthermore, carbonate microfacies of the Cretaceous(Aptian) carbonate platform in the Betic Cordillera and Jurassic carbonate platform in Tibet provide the data from case studies for the testing and initial validation of the proposed ontology. The carbonate ontology is under continuous expansion following the bottom-up approach and open access on the website of the deep-time digital Earth(DDE) program.

关键词： ontology carbonate rock carbonate petrography microfacies heterogeneous termino logy DDE knowledge graph

Magnetometer-only linear attitude estimation for bias momentum pico-satellite

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第6期11卷 455-464页

作者： Ke han Hao WANG zhong-he JIN Department of Information Science and Electronic Engineering Zhejiang University Hangzhou 310027 China

Satellite attitude information is essential for pico-satellite applications requiring light-weight,low-power,and fast-computation *** objective of this study is to provide a magnetometer-only attitude estimation method for a low-altitude Earth orbit,bias momentum *** on two assumptions,the spacecraft spherical symmetry and damping of body rates,a linear kinematics model of a bias momentum satellite's pitch axis is derived,and the linear estimation algorithm is *** algorithm combines the linear Kalman filter(KF) with the classic three-axis attitude determination method(TRIAD).KF is used to estimate satellite's pitch axis orientation,while TRIAD is used to obtain information concerning the satellite's three-axis *** tests confirmed that the algorithm is suited to the time-varying model errors resulting from both *** estimate result keeps tracking satellite attitude motion during all damping,stable,and free rotating control *** with nonlinear algorithms,such as extended Kalman filer(EKF) and square root unscented Kalman filer(SRUKF),the algorithm presented here has an almost equal performance in terms of convergence time and estimation accuracy,while the consumption of computing resources is much lower.

关键词： Pico-satellite Attitude estimation Bias momentum Magnetometer Kalman filter(KF)