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The critical case for a Berestycki-Lions theorem

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Science China Mathematics 2014年第3期57卷 541-554页

作者： zhang jian ZOU WenMing Department of Mathematical Sciences Tsinghua University

We consider the existence of the ground states solutions to the following Schrodinger equation -△u ＋ V（x）u = f（u）, u ∈ H1（RN）, where N ） 3 and f has critical growth. We generalize an earlier theorem due to ... 详细信息

关键词： meromorphic function normal family the sequence of omitted functions

Retrieving Topological Information of Implicitly Represented Diffuse Interfaces with Adaptive Finite Element Discretization

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Communications in Computational Physics 2013年第5期13卷 1209-1226页

作者： jian zhang Qiang Du Supercomputing center Chinese Academy of SciencesBeijingP.R.China Department of Mathematics Pennsylvania State UniversityUniversity ParkPA 16802USA State Key Laboratory of Space Weather Chinese Academy of SciencesBeijingP.R.China

We consider the finite element based computation of topological quantities of implicitly represented surfaces within a diffuse interface *** an adaptive finite element implementation with effective gradient recovery techniques,we discuss how the Euler number can be accurately computed directly from the numerically solved phase field functions or order *** examples and applications to the topological analysis of point clouds are also presented.

关键词： Diffuse interface model phase field method Euler number Gauss curvature adaptive finite element gradient recovery

Mechanical model of control of key strata in deep mining

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Mining Science and Technology 2011年第2期21卷 267-272页

作者： Pu Hai zhang jian State Key Laboratory of Geomechanics and Deep Underground Engineering Xuzhou 221008 China School of Mechanics and Civil Engineering China University of Mining ＆ Technology Xuzhou 221116 China

Based on the characteristic of deep rock layers and the theory of key strata,we analysed elastic mechanical characteristics of key strata by using elastic plate *** results show that the deformation and distribution of internal forces of key strata vary with different mine boundary *** boundary values of key strata with three point boundaries and one fixed boundary is greater than that with four fixed *** the rheology of key strata under low stress conditions,we selected a generalized Kelvin model to analyse the rheology characteristics of the key strata and discovered their instantaneous elastic *** rate of deformation decreased over time to the point where the key strata reached *** over this time,the effect on deformation became very clear. For high stress conditions,we chose a Burgers model and found deformation of key strata in the form of attenuation and steady-state creep and although the rate of deformation remained constant,secondary creep was obvious,causing instability in the *** well,we analysed the effect of creep buckling and derived a relation between buckling force and time.

关键词： Deep mining Key strata Rheology Creep buckling

Vapor-assisted epitaxial growth of porphyrin-based MOF thin film for nonlinear optical limiting

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Science China Chemistry 2020年第8期63卷 1059-1065页

作者： Yi-Hong Xiao Zhi-Gang Gu jian zhang State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China University of Chinese Academy of Sciences Beijing 100049China

Fabrication of metal-organic frameworks(MOFs)thin films has been an efficient way to expand their functionalities and ***,we use the vapor-assisted deposition(VAD)method to epitaxially grow a porphyrin-based MOF PCN-222 *** is,vapor source assists to deposit pre-treated precursor solution on quartz substrate to form a continuous PCN-222 ***,utilizing the post-treated encapsulation of functional carbon-based nanoparticles,the carbon nanodots(CND)and Pt doped CND(Pt/CND)are well loaded into the pores of PCN-222 film,the size(~3.1 nm)of which is highly close to the pore size of the corresponding MOF(~3.7 nm).The Z-scan results reveal that PCN-222 film exhibits high reverse saturable *** addition,encapsulation of carbon based nanodots into PCN-222 film could enhance the nonlinear optical limiting effect benefiting from the host-guest *** study serves to present both the available toolbox of thin film preparation and high potential for precise synthetic nanocomposite films in optical limiting devices.

关键词： metal-organic framework epitaxial growth porphyrin thin film nonlinear optical property

Preparation and control mechanism of anisotropic Sm-Pr-Co/Co nanocomposites with unusual continuous soft-phase coatings

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Journal of Rare Earths 2022年第7期40卷 1091-1097页

作者： Fengqing Wang Xiaojie Hu Youhao Liu jian zhang CAS Key Laboratory of Magnetic Materials and Devices Ningbo Institute of Materials Technology and EngineeringChinese Academy of Sciences(CAS)Ningbo 315201China State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201China State Key Laboratory of Rare Earth Permanent Magnetic Materials Hefei 231500China

To produce nanocomposite materials with high magnetic properties,studies concerning nanostructural processing technologies and control mechanisms are urgently required in aspects of achieving perfect alignment of the hard phase while keeping desired sizes and distributions of the soft *** the present study,a designed low-rate electroless deposition method is found to be an effective way in producing stro ng textured anisotropic Sm-Pr-Co/Co nanocomposites with unusual continuous soft-phase coatings when assembling Co particles on the ball-milled anisotropic Sm-Pr-Co hard *** average particle size of the soft-phase coatings is 18-50 nm and the obtained Sm-Pr-Co/Co composites exhibit a high intrinsic coercivity of H_(ci)=748 kA/m with an enhanced remanence of M_(r)=79 A·m^(2)/g,as compared to H_(ci)=836 kA/m and M_(r)=68 A·m^(2)/kg for uncoated Sm-Pr-Co hard ***,the coating process study reveals a nucleation control mechanism for the formation of the continuous coating ***-sized Sm-Pr-Co/Co nanocomposites with tailored size below 300 nm or even below 100 nm were also produced by this designed *** study is of theoretical and practical importance for developing advanced nanostructures including the next generation permanent magnets.

关键词： Nanocomposite magnets Texture Electroless deposition Evolution Nucleation Rare earths

Product Specification Analysis for Modular Product Design Using Big Sales Data

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Chinese Journal of Mechanical Engineering 2023年第1期36卷 19-33页

作者： jian zhang Bingbing Li Qingjin Peng Peihua Gu Department of Mechanical Engineering Shantou UniversityShantou515063China Department of Mechanical Engineering University of ManitobaManitobaR3T 5V6Canada International Institute for Innovative Design and Intelligent Manufacturing of Tianjin University Shaoxing312000China School of Mechanical Engineering Tianjin UniversityTianjin300350China

Big data on product sales are an emerging resource for supporting modular product design to meet diversified customers’requirements of product specification *** better facilitate decision-making of modular product design,correlations among specifications and components originated from customers’conscious and subconscious preferences can be investigated by using big data on product *** study proposes a framework and the associated methods for supporting modular product design decisions based on correlation analysis of product specifications and components using big sales *** correlations of the product specifications are determined by analyzing the collected product sales *** building the relations between the product components and specifications,a matrix for measuring the correlation among product components is formed for component *** rules for supporting the decision making of modular product design are proposed based on the frequency analysis of the specification values per component cluster.A case study of electric vehicles illustrates the application of the proposed method.

关键词： Modular product design Customer preference Product specifications Correlation analysis Big sales data Electric vehicle

Tunable chiroptical application by encapsulating achiral lanthanide complexes into chiral MOF thin films

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Nano Research 2022年第2期15卷 1102-1108页

作者： Rui Zhai Yihong Xiao Zhigang Gu jian zhang State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China College of Chemistry and Materials Science Fujian Normal UniversityFuzhou 350007China Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou 350108China University of Chinese Academy of Sciences Beijing 100049China

Chiral metal-organic frameworks(chirMOFs)have been widely considered on enantioselective adsorption/separation,asymmetric catalysis,biological and nonlinear optical ***,chirMOFs are facing a great challenge in development of chiroptical thin films with circularly polarized luminescence(CPL)***,we first report CPL thin films by encapsulating achiral lanthanide complexes Ln(acac)_(3)(Ln=Eu_(a)Tb_(b)Gd_(c))into the pores of surface-coordinated chirMOF thin films(SURchirMOF)[Zn_(2)(cam)_(2)dabco]_(n) with layer by layer(Ibl)encapsulation *** to the unique combination of chiral porous MOF and adjustable luminescent complexes in the host-guest thin films,the obtained Ln(acac)_(3)@SURchirMOF possess strong and tunable CPL property with high dissymmetry *** compared CPL and fluorescent lifetime results show that the advantage of this preparation strategy can effectively achieve energy transfer from Ln(acac)_(3) to SURchirMOF,resulting in an excellent CPL *** study not only provides a novel strategy to develop new types of chiral thin films but also offers an efficient approach for tunable chiroptical applications.

关键词： metal-organic frameworks lanthanide complexes thin films encapsulation chiral optical application

Vibration of axially moving beam supported by viscoelastic foundation

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Applied Mathematics and Mechanics(English Edition) 2017年第2期38卷 161-172页

作者： Haijuan zhang jian MA Hu DING Liqun CHEN Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China School of Mechanical Engineering Anhui University of Technology Maanshan 243032 Anhui Province China Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai University Shanghai 200072 China Department of Mechanics College of Sciences Shanghai University Shanghai 200444 China

In this paper, transverse vibration of an axially moving beam supported by a viscoelastic foundation is analyzed by a complex modal analysis method. The equation of motion is developed based on the generalized Hamilton＇s principle. Eigenvalues and eigenfunctions are semi-analytically obtained. The governing equation is represented in a canonical state space form, which is defined by two matrix differential operators. The orthogonality of the eigenfunctions and the adjoint eigenfunctions is used to decouple the system in the state space. The responses of the system to arbitrary external excitation and initial conditions are expressed in the modal expansion. Numerical examples are presented to illustrate the proposed approach. The effects of the foundation parameters on free and forced vibration are examined.

关键词： axially moving beam viscoelastic foundation complex modal analysis,natural frequency forced vibration

Sorption removal of cephalexin by HNO_3 and H_2O_2 oxidized activated carbons

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Science China Chemistry 2012年第9期55卷 1959-1967页

作者： LIU WeiFeng XIE HuiJun zhang jian zhang ChengLu Shandong Key Laboratory of Water Pollution Control and Resource Reuse School of Environmental Science and EngineeringShandong UniversityJinan 250100China Environment Research Institute Shandong UniversityJinan 250100China

Cephalexin＇s traces within pharmaceutical effluents have toxic impact toward ecological and human health. Low-cost activated carbon derived from Trapa natans husk was oxidized with hydrogen peroxide and nitric acid, and tested for their ability to re- move cephalexin from aqueous solutions. Oxidization with H202 showed negative effect on the cephalexin sorption, whereas HNO3 oxidization improved the adsorption. The cephalexin adsorption isotherms on the native and HNO3 oxidized carbons correlated well with the Freundlich equation while their kinetics followed the pseudo-second order model. The removal of cephalexin by the native and HNO3 oxidized carbons was found to be most favored at low ionic strength and strong acidic conditions. Based on the thermal and FTIR analyses, the interaction mechanisms of the interaction between cephalexin and the carbons were proposed. Electrostatic attraction, hydrophobic interaction and chemical bonding with surface functional groups were demonstrated as primary mechanisms for cephalexin removal. The nitrogen functionalities on the carbon surface were considered to be an important factor affecting the adsorption process.

关键词： cephalexin activated carbon oxidation adsorption mechanism