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Properties of Toeplitz Operators on the Dirichlet Space Over the Ball

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Acta Mathematica Sinica,English Series 2019年第10期35卷 1617-1628页

作者： yin yin hu Yu Feng LU Liu LIU Department of Mathematics Dalian Maritime UniversityDalian 116024P.R.China Department of Mathematics Dalian University of TechnologyDalian 116024P.R.China

On the Dirichlet space of the unit ball, we study some algebraic properties of Toeplitz operators. We give a relation between Toeplitz operators on the Dirichlet space and their analogues defined on the Hardy space. Based on this, we characterize when finite sums of products of Toeplitz operators are of finite rank. Also, we give a necessary and sufficient condition for the commutator and semi-commutator of two Toeplitz operators being zero.

关键词： Toeplitz operator pluriharmonic symbols Dirichlet space

Quantum Transport and Surface Scattering in Magnetic Metallic Film

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Communications in Theoretical Physics 2008年第9期50卷 771-776页

作者： hu yin DONG Zheng-Chao Department of Physics Huaiyin Teachers College Huaian 223001 China Key Laboratory for Chemistry of Low-Dimensional Materials of Jiangsu Province Huaian 223001 China

Taking into account the quantum size effect and the spin dependence of the electronic band structure,and including the spin dependence of the scattering from bulk impurities and two different sets of surface roughness,wepresent a theory on the electronic transport in magnetic film,in which the average autocorrelation function (ACF) forsurface roughness is described by a Gaussion *** result shows that the conductivity is a sensitive function ofsurface roughness and exchange *** is also found that in the thin film limit and in the lower-order approximationof the surface scattering,the total conductivity is given by a sum of conductivities of all the subbands and the two spinchannels,for each subband and each spin channel the scattering rates due to the impurities and two surfaces are additive.

关键词： magnetic metallic film surface scattering magnetic exchange splitting

Compact Toeplitz Operators on the Weighted Dirichlet Space

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Acta Mathematica Sinica,English Series 2015年第1期31卷 35-43页

作者： Yu Feng LU yin yin hu Liu LIU School of Mathematical Sciences Dalian University of Technology

In this paper, we completely characterize the compactness of Toeplitz operators with con- tinuous symbol on the weighted Dirichlet space.

关键词： Toeplitz operator Dirichlet space compactness

An Efficient Boron Source Activation Strategy for the Low‑Temperature Synthesis of Boron Nitride Nanotubes

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Nano-Micro Letters 2025年第1期17卷 548-558页

作者： ying Wang Kai Zhang Liping Ding Liyun Wu Songfeng E Qian He Nanyang Wang hui Zuo Zhengyang Zhou Feng Ding Yue hu Jin Zhang Yagang Yao National Laboratory of Solid State Microstructures College of Engineering and Applied SciencesJiangsu Key Laboratory of Artificial Functional Materialsand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093People’s Republic of China School of Electronic Information and Artificial Intelligence Shaanxi University of Science&TechnologyXian 710000People’s Republic of China College of Bioresources Chemical and Materials Engineering Shaanxi University of Science&TechnologyXian 710000People’s Republic of China Key Laboratory of Carbon Materials of Zhejiang Province College of Chemistry and Materials EngineeringWenzhou UniversityWenzhou 325000People’s Republic of China Shenzhen Institutes of Advanced Technology Chinese Academy of SciencesShenzhen 518000People’s Republic of China College of Chemical and Molecular Engineering Peking UniversityBeijing 100871People’s Republic of China

Lowering the synthesis temperature of boron nitride nanotubes(BNNTs)is crucial for their *** primary reason for adopting a high temperature is to enable the effective activation of highmelting-point solid *** this study,we developed a novel approach for efficiently activating boron by introducing alkali metal compounds into the conventional MgO–B *** approach can be adopted to form various low-melting-point AM–Mg–B–O growth *** growth systems have improved catalytic capability and reactivity even under low-temperature conditions,facilitating the synthesis of BNNTs at temperatures as low as 850℃.In addition,molecular dynamics simulations based on density functional theory theoretically demonstrate that the systems maintain a liquid state at low temperatures and interact with N atoms to form BN *** findings offer novel insights into the design of boron activation and are expected to facilitate research on the low-temperature synthesis of BNNTs.

关键词： Boron nitride nanotubes Low-temperature Boron activation Density functional theory

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Frontiers of Information Technology & Electronic Engineering 2016年第3期17卷 212-223页

作者： Xiao-hu MA meng YANG Zhao ZHANG School of Computer Science and Technology Soochow University State Key Laboratory for Novel Software Technology Nanjing University

The feature extraction algorithm plays an important role in face recognition. However, the extracted features also have overlapping discriminant information. A property of the statistical uncorrelated criterion is that it eliminates the redundancy among the extracted discriminant features, while many algorithms generally ignore this property. In this paper, we introduce a novel feature extraction method called local uncorrelated local discriminant embedding(LULDE). The proposed approach can be seen as an extension of a local discriminant embedding(LDE)framework in three ways. First, a new local statistical uncorrelated criterion is proposed, which effectively captures the local information of interclass and intraclass. Second, we reconstruct the affinity matrices of an intrinsic graph and a penalty graph, which are mentioned in LDE to enhance the discriminant property. Finally, it overcomes the small-sample-size problem without using principal component analysis to preprocess the original data, which avoids losing some discriminant information. Experimental results on Yale, ORL, Extended Yale B, and FERET databases demonstrate that LULDE outperforms LDE and other representative uncorrelated feature extraction methods.

关键词： Feature extraction Local discriminant embedding Local uncorrelated criterion Face recognition

Tailor-made high elasticity and low-hysteresis hydrogels based on asymmetric H-bonding crosslinking for wearable applications

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Science China Chemistry 2025年

作者： Xiaofang Shi Nan Shi Miaomiao Dang Chengyu Ji yingjie Li Peiyi Wu Zhiguo hu Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals Henan Engineering Laboratory of Chemical Pharmaceutical and Biomedical Materials School of Chemistry and Chemical Engineering Henan Normal University State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Chemistry Chemical Engineering and Biotechnology & Center for Advanced Low-dimension Materials Donghua University

The conventional method of fabricating hydrogels constantly confronts the conflict between elasticity and toughness, limiting their repetitive application. Achieving the desired elasticity through a simple and low-cost approach is a significant challenge for hydrogels, particularly through rational molecular design. Here, low-hysteresis and high-toughness hydrogels are developed from the design of a new feature monomer, N-acryloylethylsemicarbazide (NACE). Based on a concept of “asymmetric Hbonding design”, the unique double and triple H-bonding of NACE can result in a novel asymmetric crosslinking polymer with alternating strong and weak H-bonding regions. The NACE is copolymerized with acrylamide (AM) to regulate the mechanical properties of hydrogel via H-bonding density. The P(NACE-AM) ionic hydrogels are obtained simply and rapidly via one-step photopolymerization without a chemical cross-linking agent. The P(NACE-AM) hydrogels combine superb mechanical elasticity and toughness, and excellent ionic conductivity, showing great potential as durable ionic conductive devices for wearable utilization.

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ANURBS-Enhanced Finite Volume Method for Steady Euler Equations with Goal-Oriented h-Adaptivity

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Communications in Computational Physics 2022年第7期32卷 490-523页

作者： Xucheng meng Guanghui hu Research Center for Mathematics Beijing Normal UniversityZhuhai 519087China BNU-HKBU United International College Zhuhai 519087China Department of Mathematics University of MacaoMacao SARChina ZhuhaiUMScience and Technology Research Institute ZhuhaiGuangdong ProvinceChina Guangdong-Hong Kong-Macao Joint Laboratory for Data-Driven Fluid Dynamics and Engineering Applications University of MacaoMacao SARChina

In[A NURBS-enhanced finite volume solver for steady Euler equations,***,***,***.,Vol.359,pp.77–92],aNURBS-enhanced finite volume method was developed to solve the steady Euler equations,in which the desired high order numerical accuracy was obtained for the equations imposed in the domain with a curved *** this paper,the method is significantly improved in the following ways:(i)a simple and efficient point inversion technique is designed to compute the parameter values of points lying on a NURBS curve,(ii)with this new point inversion technique,the h-adaptive NURBS-enhanced finite volume method is introduced for the steady Euler equations in a complex domain,and(iii)a goal-oriented a posteriori error indicator is designed to further improve the efficiency of the algorithm towards accurately calculating a given quantity of *** results obtained from a variety of numerical experiments with different flow configurations successfully show the effectiveness and robustness of the proposed method.

关键词： Steady Euler equations NURBS-enhanced finite volume method goal-oriented a posteriori error estimation non-oscillatory k-exact reconstruction point inversion

Simplified design of nonlinear damper parameters and seismic responses for long-span cable-stayed bridges with nonlinear viscous dampers

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Frontiers of Structural and Civil Engineering 2024年第7期18卷 1103-1116页

作者： huihui LI Lifeng LI Rui hu meng YE College of Civil and Transportation Engineering Shenzhen UniversityShenzhen 518060China Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering Shenzhen UniversityShenzhen 518060China College of Civil Engineering Hunan UniversityChangsha 410082China

Viscous dampers are widely used as passive energy dissipation devices for long-span cable-stayed bridges for mitigation of seismic load-induced ***,complicated finite element(FE)modeling,together with repetitive and computationally intensive nonlinear time-history analyses(NTHAs)are generally required in conventional design *** streamline the preliminary design process,this paper developed a simplified longitudinal double degree of freedom model(DDFM)for single and symmetric twin-tower cable-stayed *** on the proposed simplified longitudinal DDFM,the analytical equations for the relevant mass-and stiffness-related parameters and longitudinal natural frequencies of the structure were derived by using analytical and energy *** of the relationship between the nonlinear viscous damper parameters and the equivalent damping ratio was achieved through the equivalent linearization ***,the analytical equations of longitudinal seismic responses for long-span cable-stayed bridges with nonlinear viscous dampers were *** on the developed simplified DDFM and suggested analytical equations,this paper proposed a simplified calculation framework to achieve a simplified design method of nonlinear viscous damper ***,the effectiveness and applicability of the developed simplified longitudinal DDFM and the proposed calculation framework were further validated through numerical analysis of a practical cable-stayed ***,the results indicated the following.1)For the obtained fundamental period and longitudinal stiffness,the differences between results of the simplified longitudinal DDFM and numerical analysis were only 2.05%and 1.5%,respectively.2)Relative calculation errors of the longitudinal girder-end displacement and bending moment of the bottom tower section of the bridge obtained from the simplified longitudinal DDFM were limited to less than 25%.3)The equivalent damping ratio of nonline

关键词： cable-stayed bridges viscous dampers simplified analytical model equivalent damping ratio seismic mitigation

Nonlinear vibrations of a composite circular plate with a rigid body

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Applied Mathematics and Mechanics(English Edition) 2023年第6期44卷 857-876页

作者： ying meng Xiaoye MAO hu DING Liqun CHEN Shanghai Institute of Applied Mathematics and Mechanics School of Mechanics and Engineering ScienceShanghai UniversityShanghai 200444China

The influence of weights is usually ignored in the study of nonlinear vibrations of *** this paper,the effect of structure weights on the nonlinear vibration of a composite circular plate with a rigid body is *** nonlinear governing equations are derived from the generalized Hamilton's principle and the von Kármán plate *** equilibrium configurations due to weights are determined and validated by the finite element method(FEM).A nonlinear model for the vibration around the equilibrium configuration is ***,the natural frequencies and amplitude-frequency responses of harmonically forced vibrations are *** study shows that the structure weights introduce additional linear and quadratic nonlinear terms into the dynamical *** leads to interesting *** example,considering weights increases the natural ***,when the influence of weights is considered,the vibration response of the plate becomes asymmetrical.

关键词： composite circular plate weight nonlinear vibration equilibrium configuration natural frequency