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Generalized Rectangular Convexity

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Acta Mathematica Sinica,English Series 2023年第9期39卷 1795-1804页

作者： Li ping yuan Tudor Zamfirescu School of Mathematical Sciences Hebei Normal UniversityShijiazhuang050024P.R.China Hebei International Joint Research Center for Mathematics and Interdisciplinary Science Shijiazhuang050024P.R.China Hebei Key Laboratory of Computational Mathematics and Applications Shijiazhuang050024P.R.China Fachbereich Mathematik TU Dortmund44221DortmundGermany Institute of Mathematics“Simion Stoilow” Romanian AcademyBucharestRomania

In this paper we investigate the tr-convexity and the rectangular biconvexity in Euclidean spaces.

关键词： tr-convex thin rectangular convexity rectangular biconvexity

A self-tuning control method for Wiener nonlinear systems and its application to process control problems

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Chinese Journal of Chemical Engineering 2017年第2期25卷 193-201页

作者： ping yuan Bi Zhang Zhizhong Mao College of Information Science & Engineering Northeastern University Shenyang 110819 China State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang 110819 China

Many chemical processes can be modeled as Wiener models, which consist of a linear dynamic subsystem followed by a static nonlinear block. In this paper, an effective discrete-time adaptive control method is proposed for Wiener nonlinear systems with uncertainties. The parameterization model is derived based on the inverse of the nonlinear function block. The adaptive control method is motivated by self-tuning control and is derived from a modified Clarke criterion function, which considers both tracking properties and control efforts. The uncertain parameters are updated by a recursive least squares algorithm and the control law exhibits an explicit form. The closed-loop system stability properties are discussed. To demonstrate the effectiveness of the obtained results, two groups of simulation examples including an application to composition control in a continuously stirred tank reactor(CSTR) system are studied.

关键词： Wiener systemsAdaptive controlUncertaintiesStabilityCSTR

MOTION OF TRACER PARTICLES IN A CENTRIFUGAL PUMP AND ITS TRACKING CHARACTERISTICS

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Journal of Hydrodynamics 2012年第5期24卷 785-793页

作者： LI Ya-lin yuan Shou-qi TANG Yue yuan Jian-ping Research Center of Fluid Machinery Engineering and Technology Jiangsu University Zhenjiang 212013 China

The Basset-Boussinesq-Oseen （BBO） equation can be used for most flows to trace the motion of a particle, but in a centrifugal pump, among the forces that act on the particles, one should also include those due to the impeller rotation, as additional effects. This paper firstly reviews various approximations of the BBO equation for the motion of dispersion particles in a viscous fluid. Then based on the motion equation for particles in low Reynolds number centrifugal pumps, a formula for calculating the tracking characteristics of tracer particles is deduced through the Fourier integral transformation. After that the deviations of the particle motion from the fluid motion, as predicted by the various approximations, are discussed and compared. At last, with an emphasis on the Particle Image Velocimetry （PIV） results, the tracking characteristics of particles are estimated. Also, advantages and disadvantages of different tracer particles are discussed and suitable tracer particles for application in PIV studies for flow fields in centrifugal pumps are suggested.

关键词： tracer particles equations of motion tracking characteristics centrifugal pump Particle Image Velocimetry (PIV)

Boosting multi-features with prior knowledge for mini unmanned helicopter landmark detection

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第2期9卷 256-261页

作者： Qin-yuan REN ping LI Bo HAN The State Key Laboratory of Industrial Control Technology Zhejiang University Hangzhou 310027 China

Without sufficient real training data,the data driven classification algorithms based on boosting method cannot solely be utilized to applications such as the mini unmanned helicopter landmark image *** this paper,we propose an approach which uses a boosting algorithm with the prior knowledge for the mini unmanned helicopter landmark image *** stage forward stagewise additive model of boosting is analyzed,and the approach how to combine it with the prior knowledge model is *** approach is then applied to landmark image detection,where the multi-features are boosted to solve a series of problems,such as rotation,noises affected,*** of real flight experiments demonstrate that for small training examples the boosted learning system using prior knowledge is dramatically better than the one driven by data only.

关键词： Boosting Prior knowledge model Landmark detection

A KAM Theorem for Reversible Systems of Infinite Dimension

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Acta Mathematica Sinica,English Series 2007年第10期23卷 1777-1796页

作者： Shun Qing CHEN Xiao ping yuan Department of Mathematics Daxian Normal College Dazhou 635000 P. R. China School of Mathematical Sciences Fudan University Shanghai 200433 P. R. China Key Lab of Mathematics for Nonlinear Science (Fudan University) Ministry of Education Shanghai 200433 P. R. China

For reversible systems of infinite dimension we prove an infinitely dimensional KAM theorem with an application to the network of weakly coupled oscillators of friction. The KAM theorem shows that there are many invar... 详细信息

关键词： KAM theorem reversible system weakly coupled oscillators

Hybrid rice achievements, development and prospect in China

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Journal of Integrative Agriculture 2015年第2期14卷 197-205页

作者： MA Guo-hui yuan Long-ping China National Hybrid Rice Research and Development Centre

This article reviews the history and progress of hybrid rice development. Hybrid rice research was initiated back in 1964, and commercialized in 1976. Three-line and two-line system hybrid rice were developed in 1974 and 1995, respectively. Research on super hybrid rice, which was first launched by Ministry of Agriculture, China in 1996, is discussed, and the great progress of super hybrid rice had been achieved with a new yield record by 15.4 t ha^-1 in the 6.84 ha demonstration location in Xupu, Hunan Province, China in 2014. And the mechanism of heterosis, the techniques of hybrid seed production and the modern field managements in hybrid rice over the past decades are also discussed. Additionally, this article dealt with the intellectual property protection（IPR） and development of hybrid rice seed industry in China. Major factors that constrain hybrid rice development are analyzed and possible solutions to this problems are proposed. Finally, the authors present methods to further increase production yield, and propose an improvement for breeding super high-yielding hybrid rice based on these methods.

关键词： hybrid rice research & development achievement & progress constraint super high yield breeding

Intersystem crossing and exciton–defect coupling of spin defects in hexagonal boron nitride

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npj Computational Materials 2021年第1期7卷 537-544页

作者： Tyler JSmart Kejun Li Junqing Xu yuan ping Department of Physics University of CaliforniaSanta CruzCAUSA Lawrence Livermore National Laboratory LivermoreCAUSA Department of Chemistry and Biochemistry University of CaliforniaSanta CruzCAUSA

Despite the recognition of two-dimensional(2D)systems as emerging and scalable host materials of single-photon emitters or spin qubits,the uncontrolled,and undetermined chemical nature of these quantum defects has been a roadblock to further *** the design of extrinsic defects can circumvent these persistent issues and provide an ultimate ***,we established a complete theoretical framework to accurately and systematically design quantum defects in wide-bandgap 2D *** this approach,essential static and dynamical properties are equally considered for spin qubit *** particular,many-body interactions such as defect–exciton couplings are vital for describing excited state properties of defects in ultrathin 2D ***,nonradiative processes such as phonon-assisted decay and intersystem crossing rates require careful evaluation,which competes together with radiative *** a thorough screening of defects based on firstprinciples calculations,we identify promising single-photon emitters such as SiVV and spin qubits such as TiVV and MoVV in hexagonal boron *** work provided a complete first-principles theoretical framework for defect design in 2D materials.

关键词： defect hexagonal boron

Design of low-energy transfer from lunar orbit to asteroid in the Sun-Earth-Moon system

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Acta Mechanica Sinica 2014年第6期30卷 966-972页

作者： Ya-Min Wang Dong Qiao ping-yuan Cui School of Aerospace Engineering Beijing Institute of Technology Key Laboratory of Dynamics and Control of Flight Vehicle Ministry of Education

Asteroid exploration trajectories which start from a lunar orbit are investigated in this *** is assumed that the probe departs from lunar orbit and returns to the vicinity of Earth,then escapes from the Earth by performing a perigee maneuver.A low-energy transfer in Sun-EarthMoon system is ***,the feasible region of lowenergy transfer from lunar orbit to perigee within 5 000 km height above the Earth surface in Sun-Earth-Moon system is calculated and *** transfer types are found,i.e.,large maneuver and fast transfers,small maneuver and fast transfers,and disordered and slow *** of feasibility trajectories belong to the first two ***,the lowenergy trajectory leg from lunar orbit to perigee and a heliocentric trajectory leg from perigee to asteroid are patched by a perigee *** optimal full-transfer trajectory is obtained by exploiting the differential evolution ***,taking 4179 Toutatis asteroid as the target,some low-energy transfer trajectories are obtained and analyzed.

关键词： Lunar orbit Asteroid exploration Low-energy transfer Sun-Earth-Moon system

Nickel release rate of 18KW gold alloy for ornaments

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Rare Metals 2013年第1期32卷 33-39页

作者： Jun-ping yuan Wei Li Wen-Ming Liu Department of Materials Science and Engineering Jinan University Jewelry Institute of Guangzhou Panyu Polytechnic

Nickel is widely used as a bleaching element in white gold alloys, but it is a potential allergen. In this paper, a popular 18 KW gold alloy, often called ＂safe nickel,＂ was chosen as the experimental material; its nickel release rates under six different processing conditions were evaluated according to the EN1811 standard. The results reveal that both the surface processing method and heat treatment technology significantly affect the nickel release rate. A coarse surface releases more nickel ions than a smooth surface. The sample normalized at 700 ~C in the single region has a lower nickel release rate than the one treated at 550 ~C in the two-phase phase region, while high temperature normalizing at 800 ~C will accelerate it. All the measured nickel release rates of the experimental material under various processing conditions exceed the permitted threshold value in the Nickel Directive, which indicates that there exists the potential risk of nickel- induced allergy when it is used to make jewelries, espe- cially for piercing types.

关键词： 18 KW Gold alloy Jewelry Nickel releaserate Nickel Directive Processing conditions