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Pentagon-Containing Doublet Graphene Fragments with Edge-Dependent Spin/Charge Distribution

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Chinese Journal of Chemistry 2022年第21期40卷 2525-2530页

作者： Zongcheng Gong qin Xiang ke Li Zhuofan Xu Jinlian hu Yong Ni Sota Sato Zhe Sun Institute of Molecular Plus Departmentof ChemistryTianjin University92 Weijin RoadTianjin 300072China Department of Chemistry Southern University of Science and TechnologyShenzhenGuangdong 518055China Department of Applied Chemistry Integrated Molecular Structure Analysis LaboratorySocial Cooperation ProgramThe University of Tokyo113-8654Japan Haihe Laboratoryof Sustainable Chemical Transformations Tianjin 300192China

The synthesis of stable open-shell hydrocarbon system comprising of pentagon defects and zigzag edges remains unexplored,which can be considered as model compounds for unraveling the spin-localized states in graphene *** concise synthetic approaches,twoπ-extended fluorenyl radicals were synthesized and isolated in their crystalline state.X-ray crystallographic analysis and studies on the magnetic,optical and electrochemical properties of neutral and charged species have revealed an interesting edge-dependence of the spin/charge distribution,that is,the spin and charge distribution shifted from the pentagon defects to the zigzag edges with the elongation of *** phenomenon was unprecedented for hydrocarbon radicals and can be rationalized by the recovery of Clar Sextets in the dominant resonance ***,one of the radicals exhibited exceptional stability in air-saturated solutions with the half-life time up to 260 d,thus providing opportunities for the applications as electronic materials.

关键词： Radicals Graphene edge structure Fluorenyl radical Conjugation Clar Sextets

Turbopump Condition Monitoring Using Incremental Clustering and One-class Support Vector Machine

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Chinese Journal of Mechanical Engineering 2011年第3期24卷 474-479页

作者： hu Lei hu Niaoqing qin Guojun GU Fengshou College of Mechatronics Engineering andAutomation National University of Defense Technology Changsha 410073 China University ofhuddersfield Huddersfield QueensgateHD13DH UK

Turbopump condition monitoring is a significant approach to ensure the safety of liquid rocket engine （LRE）.Because of lack of fault samples,a monitoring system cannot be trained on all possible condition *** it is important to differentiate abnormal or unknown patterns from normal pattern with novelty detection ***-class support vector machine （OCSVM） that has been commonly used for novelty detection cannot deal well with large scale *** order to model the normal pattern of the turbopump with OCSVM and so as to monitor the condition of the turbopump,a monitoring method that integrates OCSVM with incremental clustering is *** this method,the incremental clustering is used for sample reduction by extracting representative vectors from a large training *** representative vectors are supposed to distribute uniformly in the object region and fulfill the *** training OCSVM on these representative vectors yields a novelty *** applying this method to the analysis of the turbopump＇s historical test data,it shows that the incremental clustering algorithm can extract 91 representative points from more than 36 000 training vectors,and the OCSVM detector trained on these 91 representative points can recognize spikes in vibration signals caused by different abnormal events such as vane shedding,rub-impact and sensor *** monitoring method does not need fault samples during training as classical recognition *** method resolves the learning problem of large samples and is an alternative method for condition monitoring of the LRE turbopump.

关键词： novelty detection condition monitoring incremental clustering one-class support vector machine turbopump

Study on interface failure of shape memory alloy(SMA)reinforced smart structure with damages

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Acta Mechanica Sinica 2005年第3期21卷 286-293页

作者： Zili hu ke Xiong Xinwei Wang The Aeronautical Science key Laboratory for Smart Materials and Structures Nanjing University of Aeronautics and Astronautics. Nanjing 210016 China

Shape memory alloy （SMA） reinforced smart structure can be used to make structural shape and strength selfadapted and structural damage self-restrained. Although SMA smart structures without damages were extensively studied, researches on SMA smart structures with damages have rarely been reported thus far. In this paper, thermo-mechanical behaviors of SMA fiber reinforced smart structures with damages are analyzed through a shear lag model and the variational principle, Mathematical expressions of the meso-displacement field and the stress-strain field of a typical element with damages are obtained, and a failure criterion for interface failure between SMA fibers and matrix is established, which is applied to an example. Results presented herein may provide a theoretical foundation for further studies on integrity of SMA smart structures.

关键词： Smart structures Damages SMA Failure Meso-mechanics analysis Variational principle

Ideals in the Roe Algebras of Discrete Metric Spaces with Coefficients in B(H)

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Chinese Annals of Mathematics,Series B 2009年第2期30卷 139-144页

作者： Yingjie hu qin WANG Department of Applied Mathematics Donghua University Shanghai 201620 China

The notion of an ideal family of weighted subspaces of a discrete metric space X with bounded geometry is introduced. It is shown that, if X has Yu’s property A, the ideal structure of the Roe algebra of X with coefficients in B(H) is completely characterized by the ideal families of weighted subspaces of X, where B(H) denotes the C*-algebra of bounded linear operators on a separable Hilbert space H.

关键词： Roe algebra Ideal Metric space Coarse geometry Band-dominatedoperator

Accelerating evaluation of converged lattice thermal conductivity

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npj Computational Materials 2018年第1期4卷 647-652页

作者： Guangzhao qin Ming hu Institute of Mineral Engineering Division of Materials Science and EngineeringFaculty of Georesources and Materials EngineeringRWTH Aachen UniversityAachen 52064Germany Aachen Institute for Advanced Study in Computational Engineering Science(AICES) RWTH Aachen UniversityAachen 52062Germany

High-throughput computational materials design is an emerging area in materials science,which is based on the fast evaluation of physical-related *** lattice thermal conductivity(κ)is a key property of materials for enormous ***,the high-throughput evaluation ofκremains a challenge due to the large resources costs and time-consuming *** this paper,we propose a concise strategy to efficiently accelerate the evaluation process of obtaining accurate and convergedκ.The strategy is in the framework of phonon Boltzmann transport equation(BTE)coupled with first-principles *** on the analysis of harmonic interatomic force constants(IFCs),the large enough cutoff radius(r^(cutoff)),a critical parameter involved in calculating the anharmonic IFCs,can be directly determined to get satisfactory ***,we find a simple way to largely(~10 times)accelerate the computations by fast reconstructing the anharmonic IFCs in the convergence test ofκwith respect to the rcutof,which finally confirms the chosen r^(cutoff) is ***-dimensional graphene and phosphorene along with bulk SnSe are presented to validate our approach,and the long-debate divergence problem of thermal conductivity in low-dimensional systems is *** quantitative strategy proposed herein can be a good candidate for fast evaluating the reliableκand thus provides useful tool for high-throughput materials screening and design with targeted thermal transport properties.

关键词： properties. conductivity thermal

Constitutive modelling of composite laminates under uniaxial compression

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Chinese Journal of Aeronautics 2019年第4期32卷 938-947页

作者： Hsuan-Teh hu Lung-Shen ke Department of Civil Engineering ‘‘National" Cheng Kung University

A nonlinear constitutive model for a single lamina is proposed for the failure analysis of composite laminates. In the material model, both fiber and matrix are assumed to behave elasticplastically and the in-plane shear is assumed to behave nonlinearly with a variable shear *** damage onset for individual lamina is detected by a mixed failure criterion, composed of the Tsai-Wu criterion and the maximum stress criterion. After damage takes place within the lamina,the fiber and in-plane shear are assumed to exhibit brittle behavior, and the matrix is assumed to exhibit degrading behavior. The proposed nonlinear material model is tested against experimental data of composite laminates subjected to uniaxial compressive loads, and good agreement is obtained.

关键词： Composite laminates Constitutive model Finite element analysis Nonlinearity Uniaxial compression

New Results on Nonexistence of Perfect p-Ary Sequences and Almost p-Ary Sequences

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Acta Mathematica Sinica,English Series 2016年第1期32卷 2-10页

作者： Hai Ying LIU ke qin FENG School of Mathematical Sciences Peking University Department of Mathematical Sciences Tsinghua University

Complex periodical sequences with lower antocorrelation values are used in CDMA comnmnieation systems and cryptography. In this paper we present new nonexistence results on perfect p-ary sequences and almost p-ary seq... 详细信息

关键词： Perfect sequence p-ary and almost p-ary sequence difference set cyclotomic field imag-inary quadratic field

Formation of carbonitride precipitates in hardfacing alloy with niobium addition

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Rare Metals 2013年第1期32卷 52-56页

作者： ke Yang qin Yang Ye-Feng Bao College of Mechanical and Electrical Engineering Hohai University

Niobium, as the most effective second-phase forming element, was added in the Fe-Crl3-C-N hard- facing alloy to get carbonitride precipitates. Morphology and composition of carbonitride in the hardfacing alloy were studied by optical microscopy, scanning electron microscopy, and electron probe microanalyzer. The ther- modynamics and the effect on the matrix of the formation of carbonitride were also discussed. It was found that niobium carbonitrides are complex Nb（C, N） precipitate distributed on grain boundary and matrix of the hardfacing alloy. Under as-welded condition, primary carbonitride particles were readily precipitated from the hardfacing alloy with large size and morphology as they were formed already during solidification. Under heat treatment condi- tion, a large number of secondary carbonitrides can pre- cipitate out with very fine size and make a great secondary hardening effect on the matrix. As a result, addition of niobium in the hardfacing alloy can prevent the formation of chromium-rich phase on grain boundaries and inter- granular chromium depletion.

关键词： Niobium Carbonitride Hardfacing alloy Precipitate

Effect of chlorine content of chlorophenols on their adsorption by mesoporous SBA-15

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Journal of Environmental Sciences 2012年第8期24卷 1411-1417页

作者： qingdong qin ke Liu Dafang Fu Haiying Gao School of Civil Engineering Southeast UniversityNanjing 210096China Department of Man-Machine and Environment Engineering Nanfing University of Aeronautics and AstronauticsNanfing 210016China

Studies on the effect of the chlorine content of chlorophenols （CPs） on their adsorption from aqueous solution by mesoporous SBA-15 are important in understanding the mechanisms of CP adsorption. In this study, three CPs with different degrees of chlorine content （i.e., 2-chlorophenol, 2,6-dichlorophenol and 2,4,6-trichlorophenol） were investigated. The effects of parameters such as temperature and solution pH were studied. The results showed that CP adsorption by SBA- 15 increased with increasing number of chlorine substituents and depended strongly on the temperature and solution pH. Thermodynamic parameters such as Gibbs free energy change （AGO）, enthalpy change （△H^0） and entropy change （△S^0） were also calculated. By comparison of the adsorption coefficient of CPs with varying physical-chemical properties （size, hydrophobicity and electron density）, we propose that hydrophobic interactions between CPs and the SBA-15 surface, as well as electron donor-acceptor （EDA） complexes between oxygen of the siloxane surface of SBA-15 （e--donor） and the n-system of the CPs （e--acceptor）, were dominant adsorption mechanisms.

关键词： chlorophenols mesoporous SBA-15 adsorption pH temperature