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SOLVING OPTIMIZATION PROBLEMS OVER THE STIEFEL MANIFOLD BY SMOOTH EXACT PENALTY fuNCTIONS

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Journal of Computational Mathematics 2024年第5期42卷 1246-1276页

作者： Nachuan xiao xin Liu The Institute of Operations Research and Analytics National University of SingaporeSingapore State Key Laboratory of Scientific and Engineering Computing Academy of Mathematics and Systems ScienceChinese Academy of Sciencesand University of Chinese Academy of SciencesChina

In this paper,we present a novel penalty model called ExPen for optimization over the Stiefel *** from existing penalty functions for orthogonality constraints,ExPen adopts a smooth penalty function without using any first-order derivative of the objective *** show that all the first-order stationary points of ExPen with a sufficiently large penalty parameter are either feasible,namely,are the first-order stationary points of the original optimization problem,or far from the Stiefel ***,the original problem and ExPen share the same second-order stationary ***,the exact gradient and Hessian of ExPen are easy to *** a consequence,abundant algorithm resources in unconstrained optimization can be applied straightforwardly to solve ExPen.

关键词： Orthogonality constraint Stiefel manifold Penalty function

Position, Singularity and Workspace Analysis of 3-PSR-O Spatial Parallel Manipulator

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Chinese Journal of Mechanical Engineering 2015年第3期28卷 437-450页

作者： SHAO Jiejie CHEN Wenyu fu xin State Key Laboratory of Fluid Power Transmission and Control Zhejiang University

Although the parallel mechanisms have the advantages of high accuracy, velocity, stiffness, and payload capacity, the shortcomings of the space utilization and workspace limit the applications in the confined space. A novel 3 degrees of freedom spatial parallel manipulator 3-PSR-O（prismatic-spherical-revolute） is proposed, which possesses a compact architecture and extended workspace while maintaining the inherent advantages of the parallel mechanisms. The direct-inverse position, singularity and workspace are investigated. The mapping method is adopted in the position analysis, and the closed form solution is derived in the form of a six order equation. The singularity analysis of the mechanism is also carried out based on the geometrical constraints, including six singularity boundaries. A feature boundary, which is independent of the prismatic joints＇ stroke limit, is obtained by integrating the six singularity boundaries. According to the formation of the reachable workspace, a concept of basic workspace is also introduced and presented in the analytical way. By demarcating the basic workspace along the central height with the feature boundary, the reachable workspace can be derived and analyzed more efficiently. Finally, a comparative study on the space utilization between the 3-PSP parallel mechanism and the new mechanism is also presented. The area of feature boundary of the new mechanism is about 140% of the 3-PSP parallel mechanism, while its installation radius is only 1/2 of the 3-PSP parallel mechanism. The proposed parallel mechanism shows great space utilization, and is ideally suited for applications in confined space occasions such as immersion lithography, nano-imprint etc.

关键词： spatial-planar parallel mechanism direct-inverse position analysis reachable workspace basic workspace feature boundary

ClCRY2 facilitates floral transition in Chrysanthemum lavandulifolium by affecting the transcription of circadian clock-related genes under short-day photoperiods

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Horticulture Research 2018年第1期5卷 138-148页

作者： Li-wen Yang xiao-hui Wen Jian-xin fu Si-lan Dai Beijing Key Laboratory of Ornamental Plants Germplasm Innovation&Molecular Breeding National Engineering Research Center for FloricultureBeijing Laboratory of Urban and Rural Ecological Environment and College of Landscape ArchitectureBeijing Forestry UniversityBeijing100083P.R.China

Plants sense photoperiod signals to confirm the optimal flowering *** studies have shown that Cryptochrome2(CRY2)functions to promote floral transition in the long-day plant(LDP)Arabidopsis;however,the function and molecular mechanism by which CRY2 regulates floral transition in short-day plants(SDPs)is still *** this study,we identified a CRY2 homologous gene,ClCRY2,from Chrysanthemum lavandulifolium,a typical *** morphological changes in the *** shoot apex and ClFTs expression analysis under SD conditions showed that adult *** completed the developmental transition from vegetative growth to reproductive growth after eight ***,ClCRY2 mRNA exhibited an increasing trend from 0 to 8 d of SD ***2 overexpression in wild-type(WT)Arabidopsis and *** resulted in early *** transcript levels of the CONSTANS-like(COL)genes ClCOL1,ClCOL4,and ClCOL5,and FLOWERING LOCUS T(FT)homologous gene ClFT1 were upregulated in ClCRY2 overexpression(ClCRY2-OE)*** under SD *** transcript levels of some circadian clock-related genes,including PSEUDO-REPONSE REGULATOR 5(PRR5),ZEITLUPE(ZTL),FLAVIN-BINDING KELCH REPEAT F-BOX 1(FKF1),and GIGANTEA(GI-1 and GI-2),were upregulated in ClCRY2-OE ***,while the expression levels of other circadian clock-related genes,such as EARLY FLOWERING 3(ELF3),ELF4,LATE ELONGATED HYPOCOTYL(LHY),PRR73,and REVEILLE8(RVE8),were downregulated in ClCRY2-OE *** under SD *** together,the results suggest that ClCRY2 promotes floral transition by fine-tuning the expression of circadian clock-related gene,ClCOLs and ClFT1 in *** under SD conditions.

关键词： folium transition circadian

STABILITY ANALYSIS OF RUNGE-KUTTA METHODS FOR NONLINEAR SYSTEMS OF PANTOGRAPH EQUATIONS

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Journal of Computational Mathematics 2005年第4期23卷 351-356页

作者： Yue-xin Yu Shou-fu Li Department of Mathematics Xiangtan University Xiangtan 411105 China

This paper is concerned with numerical stability of nonlinear systems of pantograph equations. Numerical methods based on （k, l）-algebraically stable Runge-Kutta methods are suggested. Global and asymptotic stabilit... 详细信息

关键词： Nonlinear pantograph equations Runge-Kutta methods Numerical stability Asymptotic stability

Measuring accessibility of bus system based on multi-source traffic data

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Geo-Spatial Information Science 2020年第3期23卷 248-257,I0005页

作者： Yufan Zuo Zhiyuan Liu xiao fu School of Transportation Southeast UniversityNanjingChina Jiangsu Key Laboratory of Urban ITS Jiangsu Province Collaborative Innovation Center of Modern Urban Traffic TechnologiesSoutheast UniversityNanjingChina

Accessibility is a representative indicator for evaluating the supply of bus *** studies have evaluated the accessibility from different *** the interaction among land use,bus timetable arrangement and individual factors,a more holistic accessibility measurement is proposed to combine static and dynamic characteristics from multisource traffic *** rationale of the proposed model is verified by a case study of bus system in Shenzhen,China,which is carried out to find the spatial and temporal discrepancy of service of bus *** is found that the adjustment of bus schedule to time-varying travel demand can affect accessibility of bus system and that Land-use development,average bus speed and bus facilities all have positive effects on accessibility of bus *** findings provide sig-nificant reference for transport planning and *** proposed model is not limited to accessibility measuring of bus system,but also applicable to other travel modes.

关键词： Accessibility bus system multi-source traffic data spatial-temporal distribution

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脱毒马铃薯试管苗的无土栽培及微型薯的繁殖

烟台师范学院学报（自然科学版） 2001年第4期17卷 270-274页

作者：蒋小满柏新富毕可华赵建萍烟台师范学院生物科学与技术系山东烟台264025

以“鲁引一号”马铃薯脱毒试管苗为材料 ,探讨了不同栽培条件和方法、不同生长调节剂预处理及不同收获期对脱毒试管苗微型薯形成及产量构成的影响 .结果表明 ,采用试管苗切段扦插的方法不仅繁殖率高 ,而且植株结薯率也较试管苗整株移栽... 详细信息

以“鲁引一号”马铃薯脱毒试管苗为材料 ,探讨了不同栽培条件和方法、不同生长调节剂预处理及不同收获期对脱毒试管苗微型薯形成及产量构成的影响 .结果表明 ,采用试管苗切段扦插的方法不仅繁殖率高 ,而且植株结薯率也较试管苗整株移栽的植株高 .在扦插前用吲哚丁酸 (IBA)预处理切段 ,有利于切段生根 ,但对后期植株结薯量影响不大 ,而用矮壮素(CCC)预处理切段后 ,植株的结薯期提前 ,且后期结薯量增加 .通过对苗床和育苗盘栽培比较 ,前者利于管理 ,结薯量和大薯率都较后者高 .在烟台的气候条件下 ,微型薯的收获期以 6

关键词：马铃薯脱毒试管苗无土栽培微型薯繁殖病毒防治

Masses and Sigma Terms of Pentaquarks in Chiral Perturbation Theory

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Communications in Theoretical Physics 2006年第4X期46卷 704-710页

作者： LI xiao-Ya LU xiao-fu Department of Physics Sichuan University Chengdu 610064 China Institute of Theoretical Physics the Chinese Academy of Sciences Beijing 100080 China China Center of Advanced Science and Technology (World Laboratory) Beijing 100080 China

Assuming that the recently θ＋ and other exotic resonances belong to the pentaquark i0 of SU（3）I with J^P = 1/2, we constructed a relativistic effective lagrangian in the frame work of baryon chiral perturbation theory. The masses of pentaquarks under isospin symmetry is determined by calculating the propagator to one loop, where the extended on-mass-shell renormalization scheme is applied. Using the experimental data for masses of θ＋, Ξ and N, we estimated the mass of Σ and the a terms.

关键词： pentaquark chiral perturbation theory σ term

Sigma Terms and Strangeness Contents of Baryon Octet in Modified Chiral Perturbation Theory

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Communications in Theoretical Physics 2006年第6X期46卷 1059-1064页

作者： LI xiao-Ya LUE xiao-fu Department of Physics Sichuan University Chengdu 610064 China Institute of Theoretical Physics the Chinese Academy of Sciences Beijing 100080 China China Center of Advanced Science and Technology (World Laboratory) Beijing 100080 China

In the frame work of chiral perturbation theory, a modified effective Lagrangian for meson-baryon system is constructed, where the SU（3） breaking effect for meson is considered. The difference between physical and chiral limlt decay constants is taken into account. Calculated to one 1ooi） at O（p^3）, the sigma terms and strangeness contents of baryon octet are obtained.

关键词： sigma term strangeness content chiral perturbation theory

Effects of air relief openings on the mitigation of solitary wave forces on bridge decks

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Journal of Hydrodynamics 2019年第3期31卷 594-602页

作者： Sheng-chao xiao An-xin Guo Ministry-of-Education Key Laboratory of Structural Dynamic Behavior and Control School of Civil Engineering Harbin Institute of Technology Harbin 150090 China Department of Civil Engineering The University of Queensland Brisbane 4072 Australia

For inverted T-type bridge decks, the air entrapped in the chambers between adjacent girders could increase the wave forces and lead to the destruction of the bridge decks. This paper studies the effects of the air relief openings (ARO) on the mitigation of the solitary wave-induced forces on the bridge decks. Hydrodynamic experiments are conducted for three inverted T-type decks with four, five, and six girders with different wave properties and deck clearances. The open source computational fluid dynamics toolbox OpenFOAM is adopted to conduct numerical simulations for the effects of the AROs. Since the numerical results correlate well with the measurements, the mechanism of the wave-structure interaction can be revealed by the numerical flow fields. furthermore, the relationship between the shape and the volume of the ARO and the wave forces on the bridge decks, as well as the contribution of each ARO to the effect of the wave force mitigation, is also obtained from the numerical results of the OpenFOAM. Experimental and numerical results demonstrate that the AROs could effectively reduce the vertical wave forces on the bridge decks. The effects of the AROs increase with the increase of the volume of the ARO, while the shape of the ARO has no effect on the reduction of the wave forces.

关键词： Air entrapped hydrodynamic experiment solitary wave forces bridge decks OpenFOAM