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Band gaps of elastic waves in 1-D phononic crystals with imperfect interfaces

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International Journal of minerals,Metallurgy and Materials 2009年第5期16卷 608-614页

作者： min zheng Pei-jun Wei School of Applied Science University of Science and Technology Beijing Beijing 100083 China

Band gaps of elastic waves in 1-D phononic crystals with imperfect interfaces were studied. By using the transfer matrix method （TMM） and the Bloch wave theory in the periodic structure, the dispersion equation was derived for the periodically lami- nated binary system with imperfect interfaces （the traction vector jumps or the displacement vector jumps）. The dispersion equation was solved numerically and wave band gaps were obtained in the Brillouin zone. Band gaps in the case of imperfect interfaces were compared with that in the case of perfect interfaces. The influence of imperfect interfaces on wave band gaps and some interesting phenomena were discussed.

关键词： phononic crystal transfer matrix band gap imperfect interface Bloch wave

Chiral metal phosphonates: assembly, structures and functions

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Science China Chemistry 2020年第5期63卷 619-636页

作者： Guo-Guo Weng Li-min zheng State Key Laboratory of Coordination Chemistry School of Chemistry and Chemical EngineeringCollaborative Innovation Centre of Advanced MicrostructuresNanjing UniversityNanjing 210023China

As an important class of inorganic-organic hybrid materials, metal phosphonates can exhibit versatile structures, interesting functions and high water and thermal stabilities. Despite a large number of metal phosphonates reported in the past two decades,the development of chiral metal phosphonates is still in its infancy. This review summarizes the current status in this topical field including the synthetic strategies, the crystal structures of chiral metal phosphonates reported thus far, and their physical and chemical properties. Future challenges in this promising field are also discussed.

关键词： chiral metal phosphonate structure property

IMPROVED STABILITY CRITERIA FOR UNCERTAIN LINEAR SYSTEMS WITH INTERVAL TIME-VARYING DELAY

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Journal of Systems Science & Complexity 2013年第2期26卷 175-186页

作者： zheng min XIAO Wei CHEN Qinghai College of Mechatronic Engineering and Automation Shanghai UniversityShanghai Key Laboratory of Power Station Automation Technology

This paper deals with the robust stability analysis of dynamic systems with interval time- varying delay and uncertainties. The innovation of the method includes employment of a tighter integral inequality and construction of an appropriate type of Lyapunov functional. The stability criteria derived from this method have less conservatism than some existing ones. Numerical examples are given to illustrate the effectiveness of the orooosed method.

关键词： Integral inequality robust stability time-delayed systems varying delay-decomposingLKF.

M_2(pbtcH)(phen)_2(H_2O)_2[M(Ⅱ)=Co,Ni]:Mixed-ligated metal phosphonates based on 5-phosphonatophenyl-1,2,4-tricarboxylic acid showing double chain structures

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Chinese Chemical Letters 2014年第6期25卷 835-838页

作者： Tao zheng min Ren Song-Song Bao Li-min zheng State Key Laboratory of Coordination Chemistry School of Chemistry and Chemical EngineeringNanjing University

Two new mixed-ligated metal phosphonates, M2（pbtcH）（phen）2（H2O）2 [M（Ⅱ）=Co （1）, Ni （2）] （pbtcH5 = 5-phosphonatophenyl-1,2,4-tricarboxylic acid, phen = 1,10-phenanthroline）, have been syn- thesized and characterized. Both show one-dimensional double chain structures, where the M（phen）（H2O） moieties are chelated and bridged by pbtcH4 through the carboxylate and phosphonate oxygen atoms. The chains are connected by hydrogen bonding interactions and π-π stacking, forming a three-dimensional supramolecular structure. The IR and magnetic properties of the two compounds are also investigated.

关键词： 5-Phosphonatophenyl- 1,2,4-tricarboxylic acid Cobalt Nickel Magnetic property

Viscosity Analysis on the Boltzmann Equation

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Acta Mathematica Sinica,English Series 2012年第10期28卷 2139-2152页

作者： min Ling zheng Xiao Ping YANG School of Science Huzhou Teachers College School of Science Nanjing University of Science&Technology

This paper is devoted to investigating the asymptotic properties of the renormalized so- lution to the viscosity equation δtfε ＋ v · △↓xfε = Q（fε, fε）＋ ε△vfε as ε →0＋. We deduce that the renormalized solution of the viscosity equation approaches to the one of the Boltzmann equation in L^1（（0, T） × RN × R^N）. The proof is based on compactness analysis and velocity averaging theory.

关键词： Viscosity Boltzmann equation renormalized solution viscosity coemcient defect measure

Small nanoparticles bring big prospect: The synthesis, modification,photoluminescence and sensing applications of carbon dots

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Chinese Chemical Letters 2022年第4期33卷 1659-1672页

作者： Pengli Gao Zhigang Xie min zheng School of Chemistry and Life Science Advanced Institute of Materials ScienceChangchun University of TechnologyChangchun 130022China State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China

As a new type of carbon-based fluorescent nanomaterials, carbon dots(CDs) are provided with the advantages of small size, excellent photoluminescence(PL) property, easy surface modification, robust stability,good water solubility and biocompatibility, which endow them with great potential in sensing. In this review, we first describe the preparation of CDs from different starting materials via various techniques, and pre-/post-modification strategies to modulate their PL properties. Second, we outline the optical properties of CDs, including UV-vis absorption and PL, especially the PL mechanisms of CDs are presented in detail from the size effect, molecular state, surface state and defect state. Third, we summarize the research progress of CDs in sensing environmental pollutants, bioactive substances, biological microenvironments,bacteria and viruses via different mechanisms. In addition, we envision the future development trends and prospects for CDs-based nanosensors. We believe that this type of small nanoparticles will bring about big prospect in the near future.

关键词： Carbon dots Synthesis Modification Mechanisms Sensing

The optimization of satellite orbit for Space-VLBI observation

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Research in Astronomy and Astrophysics 2021年第2期21卷 97-104页

作者： Lei Liu Wei-min zheng Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China Key Laboratory of Radio Astronomy Chinese Academy of SciencesNanjing 210008China Shanghai Key Laboratory of Space Navigation and Positioning Techniques Shanghai 200030China

By sending one or more telescopes into space,Space-VLBI(SVLBI)is able to achieve even higher angular resolution and is therefore the trend of the VLBI *** the SVLBI program,the design of satellite orbits plays an important role for the success of planned *** this paper,we present our orbit optimization scheme,so as to facilitate the design of satellite orbits for SVLBI *** achieve that,we characterize the uv coverage with a measure index and minimize it by finding out the corresponding orbit *** this way,the design of satellite orbit is converted to an optimization *** can prove that,with an appropriate global minimization method,the best orbit configuration can be found within the reasonable *** that,we demonstrate that this scheme can be used for the scheduling of SVLBI observations.

关键词： instrumentation interferometers-techniques high angular resolution-methods numerical-space vehicles instruments

Modelling Spiking Neural Network from the Architecture Evaluation Perspective

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Journal of Computer Science & Technology 2016年第1期31卷 50-59页

作者： Yu Ji You-Hui Zhang Wei-min zheng Department of Computer Science and Technology Tsinghua University Beijing 100084 China

The brain-inspired spiking neural network （SNN） computing paradigm offers the potential for low-power and scalable computing, suited to many intelligent tasks that conventional computational systems find difficult. On the other hand, NoC （network-on-chips） based very large scale integration （VLSI） systems have been widely used to mimic neuro- biological architectures （including SNNs）. This paper proposes an evaluation methodology for SNN applications from the aspect of micro-architecture. First, we extract accurate SNN models from existing simulators of neural systems, second, a cycle-accurate NoC simulator is implemented to execute the aforementioned SNN applications to get timing and energy-consumption information. We believe this method not only benefits the exploration of NoC design space but also bridges the gap between applications （especially those from the neuroscientists＇ community） and neuromorphic hardware. Based on the method, we have evaluated some typical SNNs in terms of timing and energy. The method is valuable for the development of neuromorphic hardware and applications.

关键词： spiking neural network network-on-chip architecture simulation

Polarization Effect in Co-Nb/Pd Multilayer Films

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Chinese Physics Letters 1994年第3期11卷 173-176页

作者： LIU Yihua zheng min MA Xiaoding Department of Physics Shandong UniversityJi’nan 250100

Co-Nb/Pd multilayer films with different thicknesses of Co-Nb layers have been prepared by rf sputtering.X-ray diffraction showed that the Co-Nb layers for all samples were in amorphous *** measurements showed that the Pd atoms near the Go-Nb layers are polarized by Co *** total thickness of polarization for each Pd layer is about 3.2Å.A perpendicular easy axis in Co-Nb/Pd films can be obtained when the Co-Nb layers are very thin.

关键词： state. Polarization amorphous