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ERGODIC THEOREMS FOR NON-LIPSCHITZIAN SEMIGROUPS WITHOUT CONVEXITY

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Chinese Annals of Mathematics,Series B 1998年第2期19卷 209-216页

作者： ligang MAJIPU DepartmentofMathematics Teachers＇CollegeYangzhouUniversityYangzhou225002China DepartmentofMathematics NanjingUniversityNanjing210093China

Let G be a semitopological semigroup. Let C be a nonempty subset of a Hilbert space and J ={T t:t∈G} be a representation of G as asymptotically nonexpansive type mappings of C into itself such that the common fixed point set F(J) of J in C is nonempty. It is proved that ∩s∈G co {T ts x:t∈G}∩F(J) is nonempty for each x ∈ C if and only if there exists a nonexpansive retraction P of C onto F(J) such that PT s=T sP=P for all s∈G and P(x) is in the closed convex hull of {T sx:s∈G}, x∈C . This result shows that many key conditions in [1-4, 9, 12-15 ] are not necessary.

关键词： Nonlinear ergodic theorem Non lipschitzian mappings Semigroup

SUPPRESSION OF BENDING WAVES IN A PERIODIC BEAM WITH TIMOSHENKO BEAM THEORY

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Acta Mechanica Solida Sinica 2013年第2期26卷 177-188页

作者： Tao Chen ligang Wang College of Science Harbin Engineering University

Active control of bending waves in a periodic beam by the Timoshenko beam theory is concerned. A discussion about the possible wave solutions for periodic beams and their control by forces is presented. Wave propagation in a periodic beam is studied. The transfer matrix between two consecutive unit cells is obtained based on the continuity conditions. Wave amplitudes are derived by employing the Bloch-Floquet theorem and the transfer matrix. The influences of the propagating constant on the wave amplitudes are considered. It is shown that vibrations are still needed to be suppressed in the pass-band regions. Wave-suppression strategy described in this paper is employed to eliminate the propagating disturbance of an infinite periodic beam. A minimum wave-suppression strategy is compared with the classical wave-suppression strategy.

关键词： vibration control wave beam periodic structure

A survey of sketch based modeling systems

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Frontiers of Computer Science 2016年第6期10卷 985-999页

作者： Chao DING ligang LIU School of Mathematical Sciences University of Science and Technology of China Hefei 230026 China

As 3D technology, including computer graphics, virtual reality and 3D printing, has been rapidly developed in the past years, 3D models are gaining an increasingly huge demand. Traditional 3D modeling platforms such as Maya and ZBrush, utilize ＂windows, icons, menus, pointers＂（WlMP） interface paradigms for fine-grained control to construct detailed models. However, the modeling progress can be tedious and frustrating and thus too hard for a novice user or even a well trained artist. Therefore, a more intuitive interface is needed. Sketch, an intuitive communication and modeling tool for human beings, becomes the first choice of modeling community. So far, various sketch-based modeling systems have been created and studied. In this paper, we at- tempt to show how these systems work and give a comprehensive survey. We review and categorize the systems in four aspects： the input, the knowledge they use, the modeling approach and the output. We also discuss about inherent challenges and open problems for researchers in the future.

关键词： sketch-based modeling interactive design,sketch comprehension

NiSe_(2)-CoSe_(2) with a Hybrid Nanorods and Nanoparticles Structure for Efficient Oxygen Evolution Reaction

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Chinese Journal of Structural Chemistry 2022年第1期41卷 19-24页

作者： Meng Li ligang Feng School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou 225002China

Hetero-structure induced high performance catalyst for oxygen evolution reaction(OER)in the water splitting reaction has received increased ***,we demonstrated a novel catalyst system of NiSe_(2)-CoSe_(2) consisting of nanorods and nanoparticles for the efficient OER in the alkaline *** catalyst system can be easily fabricated via a low-temperature selenization of the solvothermal synthesized NiCo(OH)x precursor and the unique morphology of hybrid nanorods and nanoparticles was found by the electron microscopy *** high valence state of the metal species was indicated by X-ray photoelectron spectroscopy study and a strong electronic effect was found in the NiSe_(2)-CoSe_(2) catalyst system compared to their *** a result,NiSe_(2)-CoSe_(2) exhibited high catalytic performance with a low overpotential of 250 mV to reach 10 mA·cm^(-2) for OER in the alkaline ***,high catalytic stability and catalytic kinetics were also *** superior performance can be attributed to the high valence states of Ni and Co and their strong synergetic coupling effect between the nanorods and nanoparticles,which could accelerate the charge transfer and offer abundant electrocatalytic active *** current work offers an efficient hetero-structure catalyst system for OER,and the results are helpful for the catalysis understanding.

关键词： oxygen evolution reaction NiSe_(2) CoSe_(2) hetero-structure electrocatalysis

Ferromagnetism in an Itinerant Electron Cluster

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Communications in Theoretical Physics 2005年第1X期44卷 188-192页

作者： ligang TIANGuang-Shan SchoolofPhysics PekingUniversityBeijing100871China

In the present paper, we study the existence of metallic ferromagnetism in a cluster of nanometer scale,which is described by the Hubbard model defined on a complete graph. Therefore, the system is highly frustrated with respect to electron hopping. By solving the model exactly, we show that its ground state is fully spin-polarized at half-filling, even if the Coulomb interaction is finite. This conclusion is in sharp contrast to the well-known result for the Hubbard model on a bipartite lattice. As a result, our exact solution strongly suggests that frustration may play an important role in causing metallic ferromagnetism.

关键词：金属铁磁性关联电子系统旋转偏振交互作用双向格子

Arabidopsis WRKY45 Interacts with the DELLA Protein RGL1 to Positively Regulate Age- Triaaered Leaf Senescence

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Molecular Plant 2017年第9期10卷 1174-1189页

作者： ligang Chen University of Chinese Academy of Sciences Beijing 100049 China

Leaf senescence can be triggered and promoted by various environmental stressors, developmental cues, and endogenous hormone signals. Several lines of evidence have suggested the involvement of WRKY transcription factors in regulating leaf senescence, but the underlying mechanisms and signaling pathways involved remain elusive. In this study, we identified Arabidopsis thaliana WRKY DNA-binding protein 45 （WRKY45） as a positive regulator of age-triggered leaf senescence. Loss of W^KY45 function resulted in increased leaf longevity in age-triggered senescence, whereas overexpression of WRKY45 significantly accelerated age-triggered leaf senescence. Consistently, expression of SENESCENCE- ASSOCIATED GENEs （SAGs） was significantly reduced in wrky45 mutants but markedly enhanced in transgenic plants overexpressing WRKY45. Chromatin immunoprecipitation assays revealed that WRKY45 directly binds the promoters of several SAGs such as SAG12, SAG13, SAG113, and SEN4. Both in vivo and in vitro biochemical analyses demonstrated that WRKY45 interacts with the DELLA pro- tein RGA-LIKE1 （RGL1）, a repressor of the gibberellin （GA） signaling pathway. We found that RGL1 repressed the transcription activation function of WRKY45, thereby attenuating the expression of its reg- ulon. Consistent with this finding, overexpression of RGL1 resulted in significantly increased leaf longevity in age-triggered senescence. Taken together, our results provide compelling evidence that WRKY45 functions as a critical component of the GA-mediated signaling pathway to positively regulate age-triggered leaf senescence.

关键词： senescence WRKY transcription factor DELLA protein gibberellin

Fast Near-duplicate Image Detection in Riemannian Space by A Novel Hashing Scheme

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Computers, Materials & Continua 2018年第9期56卷 529-539页

作者： ligang Zheng Chao Song Guangzhou University Guangzhou High Education Mega CenterGuangzhou510006China Illinois Institute of Technology 3440 South DearbornSuit 100ChicagoIL60616USA

There is a steep increase in data encoded as symmetric positive definite(SPD)matrix in the past *** set of SPD matrices forms a Riemannian manifold that constitutes a half convex cone in the vector space of matrices,which we sometimes call SPD *** of the fundamental problems in the application of SPD manifold is to find the nearest neighbor of a queried SPD *** is a popular method that can be used for the nearest neighbor ***,hashing cannot be directly applied to SPD manifold due to its non-Euclidean intrinsic *** by the idea of kernel trick,a new hashing scheme for SPD manifold by random projection and quantization in expanded data space is proposed in this *** results in large scale nearduplicate image detection show the effectiveness and efficiency of the proposed method.

关键词： Riemannian manifold congruent transformation hashing kernel trick

Hard X-ray diffraction enhanced imaging only using two crystals

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Chinese Science Bulletin 2004年第20期49卷 2120-2125页

作者： ligang WANGNan WUZiyu BeijingSynchrotronRadiationFacility.InstituteofHighEnergyPhysics.ChineseAcademyofSciences.Beijing100039.China CollegeofMachine-electronics.BeijingIndustryUniversity.Beijing100022.China

Different configurations for the monochroma-tor crystals and the analyzer crystals have been used in hard X-ray diffraction enhanced imaging (DEI) methods to over-come the complex task to adjust each of them to the ideal position. Here we present a very compact DEI configuration, and preliminary results of experiments performed at the Beijing Synchrotron Radiation Facility (BSRF) using only two crystals: the first one acting as monochromator and the second one as analyzer in the Bragg geometry. Refraction contrast images characterized by high contrast and spatial resolution are obtained and compared with absorption im-ages. Differences among these images will be outlined and discussed emphasizing the potential capabilities of this very simple layout that guarantees a high transmission efficiency.

关键词：强X-射线衍射图像增强晶体分析摇摆曲线同步加速器辐射晶体单色器

PREDICTING STATUS OF CHINESE LISTED COMPANIES BASED ON FEATURES SELECTED BY PENALIZED REGRESSION

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Journal of Systems Science and Systems Engineering 2017年第4期26卷 475-486页

作者： Rui Ma Honghao Zhao ligang Zhou School of Business Macao University of Science and Technology Macao China

China＇s companies have attracted much attention due to the development of stock market in China. The listing status of listed Chinese companies becomes an important indicator which implies the potential risk of a stock. Thus predicting the status of listed Chinese companies is obviously crucial for stockholders and investors when they make further decisions. According to the four possible listing statuses for Chinese companies, researchers formulate the above issue as a classification problem which is typical in data mining area. Plenty of classification techniques have been implemented to predict the status of the listing Chinese companies based on their financial factors. Usually, there are more than 150 financial factors for each of the listed companies, and feature selection is needed before the implementation of classification methods. In the literature, researcher used t-test with variance inflation factor （VIF） analysis to select relevant factors. However, such method can not be applied in the high dimensional case. In this paper, we apply the idea of penalized regression to select the interested factors based on a logistic regression model, and then apply popular classification methods to predict the companies＇ statuses. Our results show that the proposed method can find more representative factors and improves the prediction accuracy of the classification methods.

关键词： Classification data mining feature selection penalized regression