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On symplectic automorphisms of elliptic surfaces acting on CH_(0)

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Science China Mathematics 2023年第3期66卷 443-456页

作者： Jiabin Du Wenfei liu School of Mathematical Sciences Xiamen UniversityXiamen 361005China

Let S be a complex smooth projective surface of Kodaira dimension one. We show that the group Auts(S) of symplectic automorphisms acts trivially on the Albanese kernel CH_(0)(S)albof the 0-th Chow group CH_(0)(S), unless possibly if the geometric genus and the irregularity satisfy pg(S) = q(S) ∈ {1, 2}. In the exceptional cases, the image of the homomorphism Auts(S) → Aut(CH_(0)(S)alb) has the order at most 3. Our arguments actually take care of the group Autf(S) of fibration-preserving automorphisms of elliptic surfaces f : S → B. We prove that if σ ∈ Autf(S) induces the trivial action on Hi,0(S) for i > 0, then it induces the trivial action on CH_(0)(S)alb. As a by-product we obtain that if S is an elliptic K3 surface, then Autf(S)∩Auts(S)acts trivially on CH_(0)(S)alb.

关键词： symplectic automorphism elliptic surface Chow group

Characterization of compact quantum group

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Frontiers of Mathematics in China 2014年第2期9卷 321-328页

作者： Ming liu Xia ZHANG School of Science Tianjin Polytechnic University Tianjin 300387 China

Given a C^＊-algebra A and a comultiplication Ф on A, we show that the pair （A, Ф） is a compact quantum group if and only if the associated multiplier Hopf ^＊-algebra （A, ФA） is a compact Hopf ^＊-algebra.

关键词： Compact quantum group associated multiplier Hopf^ *-algebra compact Hopf ^*-algebra

A Monte Carlo Study of the Half-Filled Two-Dimensional Hubbard Model

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Communications in Theoretical Physics 2001年第11期36卷 625-630页

作者： ZHU Xing liu Chuan Department of Physics Peking UniversityBeijing 100871China Department of PhysicsPeking UniversityBeijing 100871China

Using the path integral representation,bulk thermodynamic properties of the two-dimensional Hubbard model on a square lattice are studied numerically using the hybrid Monte Carlo simulation *** for averaged energy,spin-spin correlation functions and Cooper pair correlation functions are *** these results suggest that the system exhibits an anti-ferromagnetic correlation at half-filling for a wide range of temperature.

关键词： strongly correlated electrons,bulk thermodynamic quantities,hybrid Monte Carlo

CRITICAL RATE OF HORIZONTAL WELL FOR WATER CREST

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Journal of Hydrodynamics 1992年第4期4卷 5-10页

作者： liu, Ciqun Wang, Xiaodong Research Inst of Porous Flow and Fluid Mechanics Academia Sinica Langfang China

Stationary water crest, for two-dimensional porous flow of horizontal well located at any position in vertical cross-section was studied. Using the potential theory for 2-D flow, the formulae and plots of the critical rate were presented. Calculated results indicate that the critical rates of horizontal well are proportional to oil zone height and horizontal length of well. Comparing with the results of the issued paper, the results in this paper obtain some new conclusions.

关键词： Flow of fluids Porous materials

The role of microRNAs in colorectal cancer

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Journal of Genetics and Genomics 2010年第6期37卷 347-358页

作者： Mao liu Huiping Chen Department of Medical Genetics Tongji Medical College of Huazhong University of Science and Technology Wuhan 430030 China

MicroRNAs are small non-coding RNAs which regulate gene expression in a post-transcriptional manner. Although the first study was published about 15 years ago, knowledge about their role in regulation of cell proliferation, differentiation, apoptosis and immunity has been greatly advanced recently. Their association with formation, angiogenesis, metastasis and chemotherapy resistance of minors has become one of the core issues in epigenetics of cancer. Here, we summarize the latest findings concerning microRNAs involved in dif- ferent signal pathways leading to colorectal cancer, introduce some new potential microRNAs as biomarkers in diagnosis and prognosis, and analyze its application in the treatment of cancer.

关键词： microRNAs colorectal cancer signal pathway biomarker cancer therapy

Bilateral self-amalgamation of a Heegaard splitting and Hempel distance

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Science China Mathematics 2015年第7期58卷 1499-1510页

作者： ZOU YanQing liu XiMin School of Mathematical Sciences Dalian University of Technology

A closed orientable Haken 3-manifold containing a non separating incompressible closed surface has two canonical Heegaard splittings, which are called self-amalgamation and bilateral *** distance introduced by Hempel is a useful index in studying Heegaard splitting. This paper studies the stabilization problem for the bilateral self-amalgamation, and proves that if the distance of bilateral selfamalgamation of a Heegaard splitting is at least 9, then it is unstabilized, weakly reducible and irreducible.

关键词： stabilization Heegaard distance subsurface projection

How Unique is ′China Model′: A Review of Theoretical Perspectives on China′s Urbanization in Anglophone Literature

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Chinese Geographical Science 2015年第1期25卷 98-112页

作者： WANG Fenglong liu Yungang School of Geography Sciences and Planning Guangdong Key Laboratory for Urbanization and Geo-simulation Sun Yat-sen University Department of Geography Hong Kong Baptist University

As a major aspect of the ′China Model′, urbanization in China is being heatedly discussed in the Anglophone literature in the last two decades. By considering China′s urbanization as a ′testing ground′ of ′western′ theories, these studies are important for the understanding of China′s ongoing urban restructuring and exchanging knowledge with ′western′ insights. Based on a survey of existing studies, this paper identifies various endogenous and exogenous concepts and explanations of China′s urbanization. It is suggested that China′s urbanization is mainly driven by a combination of political decentralization and neoliberalization with various forms of social stratification and mobility. However, it is argued that the distinctness of the ′China Model′, which is usually used to support the legitimacy of studies of China′s urbanization, has led to many controversial arguments and diminished the due contributions of Chinese scholars in the knowledge production of China′s urbanization. To consolidate the legitimacy of studies on China′s urbanization and enhance the roles of Chinese scholars, we suggest future studies to pay more attentions to the fundamental theories with looser constraints and ′true questions′ on China′s urbanization.

关键词： theoretical perspective urbanization endogenous exogenous China Model

Strong convergence results for hemivariational inequalities

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Science China Mathematics 2006年第7期49卷 893-901页

作者： liu Zhenhai ZOU Jiezhong Department of Mathematics Changsha University of Science and Technology Changsha 410076 China School of Mathematical Science and Computing Technology Central South University Changsha 410075 China School of Mathematical Science and Computing Technology Central South University Changsha 410075 China

The purpose of this paper is to study a regularization method of solutions of ill-posed problems involving hemivariational inequalities in Banach spaces. Under the assumption that the hemivariational inequality is solvable, a strongly convergent approximation procedure is designed by means of the so-called Browder-Tikhonov regularization method. Our results generalize and extend the previously known theorems.

关键词： hemivariational inequalities, Clarke subdifferential, regularization, strong convergence.

Calibration-free and model-independent method for high-DOF image-based visual servoing

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控制理论与应用（英文版） 2013年第1期11卷 132-140页

作者： Jie ZHANG Ding liu School of Automation and Information Engineering Xi'an University of Technology

This paper presents a novel method to improve the performance of high-DOF image base visual servoing （IBVS） with an uncalibrated camera. Firstly, analysis and comparison between point-based and moment-based features are carried out with respect to a 4-DOF positioning task. Then, an extended interaction matrix （IM） related to the digital image, and a Kalman filter （KF）-based estimation algorithm of the extended IM without calibration and IM model are proposed. Finally, the KF-based algorithm is extended to realize an approximation to decoupled control scheme. Experimental results conducted on an industrial robot show that our proposed methods can provide accurate estimation of IM, and achieve similar performance compared with traditional calibration-based method. Therefore, the proposed methods can be applied to any robot control system in variational environments, and can realize instant operation to planar object with complex and unknown shape at large displacement.

关键词： Image-based visual servoing Interaction matrix Image moment Kalman filter Decoupled control scheme