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Gelfand–Kirillov Dimensions of the Z^2-graded Oscillator Representations of sl(n)

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Acta Mathematica Sinica,English Series 2015年第6期31卷 921-937页

作者： zhan qiang BAI Institute of Mathematics Academy of Mathematics and System SciencesChinese Academy of Sciences

We find an exact formula of Gelfand-Kirillov dimensions for the infinite-dimensional explicit irreducible sl（n,F）-modules that appeared in the Z2-graded oscillator generalizations of the classical theorem on harmonic polynomials established by Luo and Xu. Three infinite subfamilies of these modules have the minimal Gelfand-Kirillov dimension. They contain weight modules with unbounded weight multiplicities and completely pointed modules.Service E-mail this articleAdd to my bookshelfAdd to citation managerE-mail AlertRSSArticles by authors

关键词： Gelfand-Kirillov dimension highest-weight module associated variety minimal GKdimension module universal enveloping algebra

Gelfand-Kirillov Dimension and Reducibility of Scalar Generalized Verma Modules for Classical Lie Algebras

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Acta Mathematica Sinica,English Series 2024年第3期40卷 658-706页

作者： zhan qiang BAI Jing JIANG School of Mathematical Sciences Soochow UniversitySuzhou 215006P.R.China E-mail:zqbai@*** jjsd6514@***

Let g be a classical complex simple Lie algebra and q be a parabolic *** M be a generalized Verma module induced from a one dimensional representation of *** M is called a scalar generalized Verma *** this paper,we will determine the reducibility of scalar generalized Verma modules associated to maximal parabolic subalgebras by computing explicitly the Gelfand-Kirillov dimension of the corresponding highest weight modules.

关键词： Generalized Verma module Gelfand-Kirillov dimension Young tableau

Microstructure refinement and work hardening in a machined surface layer induced by turning Inconel 718 super alloy

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International Journal of Minerals,Metallurgy and Materials 2018年第8期25卷 937-949页

作者： Xiao-ping Ren zhan-qiang Liu School of Mechanical Engineering Shandong University Key Laboratory of High Efficiency and Clean Mechanical Manufacture Ministry of EducationShandong University

The microstructural changes in the machined surface layer of Ni-based super alloys essentially determine the final performance of the structural components of aerospace engines in which these alloys are *** this work,multiscale metallurgical observations using scanning electron microscopy,electron-backscatter diffraction microscopy,and transmission electron microscopy were conducted to quantitatively characterize the microstructure of the machined ***,to elucidate the factors that affect the formation of the refinement microstructure,the distributions of the deformation parameters(strain,strain rate,and temperature) in the machined subsurface were analyzed.A dislocation–twin interaction dynamic recrystallization mechanism for grain refinement during machining of Inconel 718 is ***,microhardness evolution induced by grain refinement in the machined surface is *** results suggest that the gradient microstructure and the work hardening can be optimized by controlling the cutting parameters during turning of Inconel 718.

关键词： grain refinement dislocation–twin interaction work hardening turning Inconel 718

Prediction of temperature field in machined workpiece surface during the cutting of Inconel 718 coated with surface-active media

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Advances in Manufacturing 2023年第3期11卷 378-389页

作者： Qing-An Yin zhan-qiang Liu Bing Wang School of Mechanical Engineering Shandong UniversityJinan 250061People's Republic of China Key National Demonstration Center for Experimental Mechanical Engineering Education/Key Laboratory of High Efficiency and Clean Mechanical Manufacture of MQE Jinan 250061People's Republic of China

The heat generated and accumulated on the machined surface of an Inconel 718 workpiece causes thermal damage during the cutting ***-active media with high thermal conductivity coated on the workpiece to be machined may have the potential to reduce the generation of cutting *** this study,a theoretical model for predicting the instantaneous machined surface temperature field is proposed for surface-active thermal conductive medium(SACM)-assisted cutting based on the finite element and Fourier heat transfer *** cutting experiments were performed to verify the results predicted using the proposed surface-temperature field *** SACMs with various thermal conductivities were used to coat Inconel 718 surface to be *** embedded into the workpiece were used to measure the cutting temperature at different points on the machined workpiece surface during the cutting *** experimental results were in agreement with the predicted temperatures,and the maximum error between the experimental results and predicted temperatures was approximately 9.5%.The cutting temperature on the machined surface decreased with an increase in the thermal conductivity of the *** graphene SACM with high thermal conductivity can effectively reduce the temperature from 542℃ to 402℃,which corresponds to a reduction of approximately 26%.The temperature reduction due to SACM decreases with an increase in the distance between the temperature prediction point and machined workpiece *** conclusion,the cutting temperatures on the machined workpiece surface can be reduced by coating with SACM.

关键词： Surface-active thermal conductive media(SACM) Finite element model Cutting heat Cutting temperature Inconel 718

Gelfand–Kirillov Dimension and Reducibility of Scalar Generalized Verma Modules

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Acta Mathematica Sinica,English Series 2019年第11期35卷 1854-1860页

作者： zhan qiang BAI Wei XIAO School of Mathematical Sciences Soochow UniversitySuzhou 215006P.R.China College of Mathematics and statistics Shenzhen Key Laboratory of Advanced Machine Learning Applications Shenzhen UniversityShenzhen 518060P.R.China

The Gelfand–Kirillov dimension is an invariant which can measure the size of infinitedimensional algebraic structures. In this article, we show that it can also measure the reducibility of scalar generalized Verma modules. In particular, we use it to determine the reducibility of scalar generalized Verma modules associated with maximal parabolic subalgebras in the Hermitian symmetric case.

关键词： Gelfand–Kirillov dimension generalized Verma module reducibility

Design,Fabrication and Experiments of an Anthropomorphic Finger with Combined Compliant Joints

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Journal of Bionic Engineering 2020年第6期17卷 1152-1162页

作者： Yin zhang qiang zhan Ruixin Li Xinyu Bao Robotics Institute Beihang UniversityBeijing 100191China Whiting School of Engineerings Johns Hopkins University Baltimore 21211USA

Fingers are the basic components of anthropomorphic *** present,most anthropomorphic fingers utilize rigid joints,which have obvious fabrication and assembly complexities as well as limited flexibility and ***,some anthropomorphic fingers were attempted to utilize compliant joints learned from bioinspiration,but they have a limited self-resetting ability and lateral deformation resistance,as well as occupying a large space and having a non-anthropomorphic *** this paper,nine compliant joints for anthropomorphic fingers were analyzed using Finite Element Analysis(FEA),based on which two combined compliant joints were proposed,and the optimal one was obtained through FEA and *** anthropomorphic finger that embeds parts of the compliant joint into the adjacent phalanxes was then ***,the anthropomorphic finger was fabricated and experiments were *** results show that the anthropomorphic finger with the proposed combined compliant joints has a better self-resetting ability and lateral deformation resistance while ensuring a large range of motion similar to that of the human finger,and the required actuating force is ***,the embedded joint structure can reduce the occupied space of the joint so as to improve the anthropomorphic appearance of the finger,and enhance its lateral deformation resistance.

关键词： anthropomorphic finger compliant joint deformation stress bioinspiration

Altered 3D genome reorganization mediates precocious myeloid differentiation of aged hematopoietic stem cells in inflammation

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Science China Life Sciences 2025年

作者： Xinyu Cui Yu Dong qiang zhan Yixin Huang Qianshu Zhu Zihao zhang Guang Yang Liping Wang Shijun Shen Jia Zhao Zhiyi Lin Jiatong Sun Zhongqu Su Yihan Xiao Chuyu zhang Yuwei Liang Lu Shen Lichen Ji Xuguang zhang Jiqing Yin Hong Wang Zhiyang Chen Zhenyu Ju Cizhong Jiang Rongrong Le Shaorong Gao Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital Frontier Science Center for Stem Cells School of Life Sciences and Technology Tongji University Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education Orthopaedic Department of Tongji Hospital School of Life Sciences and Technology Tongji University Key Laboratory of Regenerative Medicine of Ministry of Education Institute of Aging and Regenerative Medicine Department of Developmental & Regenerative Medicine College of Life Science and Technology Jinan University Shandong Key Laboratory of Animal Bioengineering and Disease Prevention College of Animal Science and Technology Shandong Agricultural University Department of Joint Surgery Shanghai East Hospital Tongji University School of Medicine Shanghai Institute of Nutrition and Health Chinese Academy of Sciences

Inflammation is a driving force of hematopoietic stem cells(HSCs) aging, causing irreversible exhaustion of functional HSCs. However, the underlying mechanism of HSCs erosion by inflammatory insult remains poorly understood. Here, we find that transient LPS exposure primes aged HSCs to undergo accelerated differentiation at the expense of self-renewal, leading to depletion of HSCs. Meanwhile, the central regulator nuclear factor kappa B(NF-κB) mediating functional impairment by inflammation insult induces differential transcriptional response in aged HSCs compared with young HSCs, with precocious activation of myeloid lineage genes. Altered compartmentalization and chromatin loop formation are associated with aging-related differential transcriptional response in HSCs upon lipopolysaccharide(LPS)stimulation. Mechanistically, enhancer and promoter regions of myeloid lineage genes in aged HSCs are more accessible and display more rapid and prominent CTCF occupancy upon LPS stimulation. Our study provides comprehensive resources for the three-dimensional(3D)genome structure of HSCs and sheds light into the ordered genome organization and the associated transcriptome signature underlying HSCs aging.

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Coupled Matrix Factorization for Question Similarity

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Chinese Journal of Electronics 2016年第4期25卷 665-671页

作者： WEI Chuyuan LI Fangfang zhan qiang FAN Xiongzhong School of Computer Science and Technology Beijing Institute of Technology Department of Computer Beijing University of Civil Engineering and Architecture Advanced Analytics Institute University of TechnologySydneyAustralia

Community question answering(CQA)has provided an increasingly popular service where users ask and answer questions and access historical questionanswer *** a fundamental task in CQA,question similarity measure is to compute the similarity between the queried question and the historical questions which have been solved by other *** mine and use the most important semantic features as the semantic representation of questions,and try to incorporate the couplings of semantic features into vector space *** propose Coupled question similarity(CQS) model,and compute the similarity in matrix factorization *** conducted on real CQA data sets demonstrate that with the incorporation of such couplings,the performance of sentence similarity is improved compared to a variety of baseline methods significantly.

关键词： Sentence similarity Community question answering(CQA) Matrix factorization(MF) Coupled question similarity(CQS)

Control of a Spherical Robot: Path Following Based on Nonholonomic Kinematics and Dynamics

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Chinese Journal of Aeronautics 2011年第3期24卷 337-345页

作者： ZHENG Minghui zhan qiang LIU Jinkun CAI Yao Robotics Institute Beihang University Beijing 100191 China School of Automation Science and Electrical Engineering Beihang University Beijing 100191 China

This paper presents the controller design for the path following of a spherical mobile robot, BHQ-1. Firstly, a desired velocity for the reference path is deduced from the kinematic model, which cannot be transformed into the classic chained form. Secondly, a necessary torque for the desired velocity is obtained based on the dynamic model. As to the kinematics, a one-dimensional function is selected to measure the two-directional tracking error, and the velocity of rolling forward is reasonably assumed to be constant; therefore the multiple-input multiple-output （MIMO） system is transformed into a single-input single-output （SISO） system. As to the dynamics, both exact dynamics and inexact dynamics with modeling error as well as bounded unknown disturbance are taken into account, based on which a proportional-derivative （PD） controller and a sliding mode controller with adaptive parameters are proposed respectively. Finally, convergence analysis and simulation results are provided to validate these controllers.

关键词： spherical robot path following nonholonomic kinematics dynamics