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Rational cubic/quartic Said-Ball conics

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Applied Mathematics(A Journal of Chinese Universities) 2011年第2期26卷 198-212页

作者： hu qian-qian WANG Guo-jin Department of Mathematics Zhejiang University Hangzhou 310027 College of Statistics and Mathematics Zhejiang Gongshang University Hangzhou 310018.

In CAGD, the Said-Ball representation for a polynomial curve has two advantagesover the B′ezier representation, since the degrees of Said-Ball basis are distributed in a step *** advantage is that the recursive algorithm of Said-Ball curve for evaluating a polynomialcurve runs twice as fast as the de Casteljau algorithm of B′ezier curve. Another is that theoperations of degree elevation and reduction for a polynomial curve in Said-Ball form are simplerand faster than in B′ezier form. However, Said-Ball curve can not exactly represent conics whichare usually used in aircraft and machine element design. To further extend the utilizationof Said-Ball curve, this paper deduces the representation theory of rational cubic and quarticSaid-Ball conics, according to the necessary and su？cient conditions for conic representation inrational low degree B′ezier form and the transformation formula from Bernstein basis to Said-Ballbasis. The results include the judging method for whether a rational quartic Said-Ball curve is aconic section and design method for presenting a given conic section in rational quartic Said-Ballform. Many experimental curves are given for confirming that our approaches are correct ande？ective.

关键词： Rational Said-Ball curve Rational B′ezier curve conics.

The thermoelastic excitation of air-solid interface waves using the pulsed laser

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Science China(Physics,Mechanics & Astronomy) 2004年第2期47卷 199-207页

作者： hu Wenxiang qian Menglu Institute of Acoustics Tongji University Shanghai 200092 China Institute of Acoustics Tongji University Shanghai 200092 China

Applying the integral transform to the coupled problem of thermoelastic and heat conduction equations, the integral representation of the normal displacement field for the air-solid interface waves excited by a pulsed laser line source is obtained. The pole residues of the integrand are performed analytically, and the transient displacement field is calculated by using FFT technique. The thermoelastic excitation and detection of the air-solid interface waves is carried out by a laser ultrasonic system, on which the pulsed laser is focused into a line source onto the interface to excite the air-solid interface waves: leaky Rayleigh wave and Scholte wave, and the interface waves displacement signal is detected successfully by a SH130 laser heterodyne interferometer. The theoretic and experimental results are in good agreement.

关键词： air-solid interface, interface waves, laser ultrasonics.

The convergence rate and necessary-and-sufficient condition for the consistency of isogeometric collocation method

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Applied Mathematics(A Journal of Chinese Universities) 2022年第2期37卷 272-289页

作者： LIN Hong-wei XIONG Yun-yang hu hui YAN Jia-cong hu qian-qian School of Mathematical Science Zhejiang UniversityHangzhou 310027China Department of Mathematics Zhejiang Gongshang UniversityHangzhou 310018China

Although the isogeometric collocation(IGA-C)method has been successfully utilized in practical applications due to its simplicity and efficiency,only a little theoretical results have been established on the numerical analysis of the IGA-C *** this paper,we deduce the convergence rate of the consistency of the IGA-C ***,based on the formula of the convergence rate,the necessary and sufficient condition for the consistency of the IGA-C method is *** results advance the numerical analysis of the IGA-C method.

关键词： isogeometric collocation consistency necessary and sufficient condition convergence rate

Hyperspectral Image Super-Resolution Meets Deep Learning:A Survey and Perspective

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IEEE/CAA Journal of Automatica Sinica 2023年第8期10卷 1668-1691页

作者： Xinya Wang qian hu Yingsong Cheng Jiayi Ma the Electronic Information School Wuhan UniversityWuhan 430072China IEEE

Hyperspectral image super-resolution,which refers to reconstructing the high-resolution hyperspectral image from the input low-resolution observation,aims to improve the spatial resolution of the hyperspectral image,which is beneficial for subsequent *** development of deep learning has promoted significant progress in hyperspectral image super-resolution,and the powerful expression capabilities of deep neural networks make the predicted results more ***,several latest deep learning technologies have made the hyperspectral image super-resolution method ***,a comprehensive review and analysis of the latest deep learning methods from the hyperspectral image super-resolution perspective is *** this end,in this survey,we first introduce the concept of hyperspectral image super-resolution and classify the methods from the perspectives with or without auxiliary ***,we review the learning-based methods in three categories,including single hyperspectral image super-resolution,panchromatic-based hyperspectral image super-resolution,and multispectral-based hyperspectral image ***,we summarize the commonly used hyperspectral dataset,and the evaluations for some representative methods in three categories are performed qualitatively and ***,we briefly introduce several typical applications of hyperspectral image super-resolution,including ground object classification,urban change detection,and ecosystem ***,we provide the conclusion and challenges in existing learning-based methods,looking forward to potential future research directions.

关键词： Deep learning hyperspectral image image fusion image super-resolution survey

Bounds on partial derivatives of NURBS surfaces

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Applied Mathematics(A Journal of Chinese Universities) 2017年第3期32卷 281-293页

作者： WANG Guo-jin XU hui-xia hu qian-qian School of Mathematical Sciences Zhejiang University Institute of Mathematics Zhejiang Wanli University Department of Mathematics Zhejiang Gongshang University

In this paper, we estimate the partial derivative bounds for Non-Uniform Rational B-spline(NURBS) surfaces. Firstly, based on the formula of translating the product into sum of B-spline functions, discrete B-spline theory and Dir function, some derivative bounds on NURBS curves are provided. Then, the derivative bounds on the magnitudes of NURBS surfaces are proposed by regarding a rational surface as the locus of a rational curve. Finally, some numerical examples are provided to elucidate how tight the bounds are.

关键词： NURBS curve NURBS surface derivative bound Dir function discrete B-spline

A Privacy-preserving Energy Management System Based on Homomorphic Cryptosystem for IoT-enabled Active Distribution Network

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 167-178页

作者： qian hu Siqi Bu Wencong Su Vladimir Terzija the Department of Physics Hong Kong Baptist UniversityHong KongChina the Department of Electrical and Electronic Engineering Shenzhen Research InstituteThe Hong Kong Polytechnic UniversityHong KongChina the Department of Electrical and Computer Engineering University of Michigan-DearbornDearbornMI 48128USA the School of Engineering Newcastle UniversityNewcastleUK

Active distribution network(ADN),as a typically cyber-physical system,develops with the evolution of Internet of Things(IoTs),which makes the network vulnerable to cybersecurity *** this paper,the eavesdropping attacks that lead to privacy breaches are addressed for the IoT-enabled ADN.A privacy-preserving energy management system(EMS)is proposed and empowered by secure data exchange protocols based on the homomorphic *** the information transmission among distributed generators and load customers in the EMS,private information including power usage and electricity bidding price can be effectively protected against eavesdropping *** correctness of the final solutions,e.g.,optimal market clearing price and unified power utilization ratio,can be deterministically *** simulation results demonstrate the effectiveness and the computational efficiency of the proposed homomorphically encrypted EMS.

关键词： Eavesdropping attack energy management system homomorphic cryptosystem Internet of Things(IOTs) active distribution network(ADN) privacy-preserving

Factors affecting poplar wetwood characteristics

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Journal of Forestry Research 2023年第5期34卷 1615-1626页

作者： Qilin Zhang Xingyi hu qian hu Jiawei Yang Tianyu Zhao Kebing Du College of Horticulture and Forestry Sciences/hubei Engineering Technology Research Center for Forestry Information Huazhong Agricultural UniversityWuhan 430070People’s Republic of China hubei Academy of Forestry Wuhan 430075People’s Republic of China Xiangyang Academy of Forestry Xiangyang 441052People’s Republic of China

Wet wood is an abnormal phenomenon in growing trees,which adversely affects growth,subsequent wood processing and economic values of wood *** this study,the influences of factors such as clones,afforestation methods,site conditions and climate conditions on the characteristics of poplar wetwood were studied through field investigations in 27 clones from 48 sample plots in 28 *** showed that the incidences of wetwood were almost 100%in all *** of wetwood area among the48 plots differed from 15.1 to 90.2%.Wetwood area ratios,moisture contents and pH differed significantly between the 27 *** area ratios of the clones ranged from18.7 to 62.3%.Ratios of wetwood areas were positively correlated with wet wood moisture content and pH,tree age,and negatively correlated with pH of sap *** repeatability of wet wood area ratios was 0.52,moderately controlled by *** moisture content and pH were highly controlled by genetics,indicated by the repeatability of 0.91 and 0.89,*** were significant differences in wetwood area ratios,moisture content and pH between different site conditions,afforestation methods,and geographical *** land had the lowest wetwood area ratios and moisture content among four types of *** by direct seeding and rooted cuttings had the lowest wetwood area ratios and moisture content,*** the three geographical regions,the Yellow River Basin had the lowest wetwood values of all three factors.

关键词： Poplar Wetwood Clones Site conditions Afforestation methods

A Perspective on the Dynamics Properties in Polymer Nanocomposites

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Chinese Journal of Polymer Science 2023年第9期41卷 1355-1360,I0005页

作者： Xu-Ze Zhang Zhong-Yuan Lu hu-Jun qian State Key Laboratory of Supramolecular Structure and Materials Institute of Theoretical ChemistryCollege of ChemistryJilin UniversityChangchun130021China

Polymer nanocomposites(PNCs)usually have superior properties than pristine *** the dynamics properties in PNC system is crucial to reveal the mechanism of property change unpon the addition of nanoparticles(NPs),and therefore for a better design of the material *** this short perspective,we summarize recent advances mainly from theoretical and simulation studies of dynamics properties in polymer nanocomposite *** is the"vehicle model"which reveals that diffusion dynamics of sticky NP is coupled to surrounding chain ***,recent simulations demonstrate that such coupling also exists in all-polymer nanocomposite wich is composed of linear polymer chains and single-chain nanoparticles(SCNPs).These SCNPs have almost the same chemical composition as the matrix ***,it is assumed that such all-polymer nanocomposite can act as a model system where there are no enthalpic interactions between NPs and polymer *** the above dynamic coupling was found in the above two different systems containing inorganic NPs or relatively small organic SCNPs,it was found that the length scale of such dynamic coupling(the thickness of the matrix/NP interface)is comparable to the NP size,which is surprisingly consistent in the above two different *** addition,a chain-length dependence of the NP influence on the chain dynamics reported from a recent joint simulaiton and experimental study of all-polymer nanocomposite system,and a theoretical model developed for such phenomena are also *** the end,we give an outlook of this field,especially for possible chainlength dependence of complex dynamics in sticky-NP systems.

关键词： Polymer nanocomposite Dynamics properties Interfacial interaction

Nonepitaxial growth of a (001) textured L1_0 Fe-Pt film in H_2 and N_2 annealing atmospheres

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Rare Metals 2006年第3期25卷 260-264页

作者： WU Peiwen hu Xuerang qian Jun YUAN Jun Electron Microscope Laboratory Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

A nonepitaxial （001） textured Fe-Pt alloyed film was obtained by annealing Fe/Pt multilayers in H2. No Such nonepitaxial （001） texture was observed for similar multilayers annealed in N2 atmosphere. Sensitive electron energy loss spectroscopy and the left shift of the L10 FePt （111） diffr cfion peak indicate oxidation in the N2 annealed samples. The oxidation dramatically degrades the （001） texture of the Fe-Pt fdm and induces the composition change in the alloyed layer. The relation between the texture formation and oxidation was discussed.

关键词： metal (001) textured FePt annealing oxidation shift of diffraction peak