检索结果-南通市图书馆

Repelling periodic points of given periods of rational functions

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2006年第9期49卷 1165-1174页

作者： chang Jianming fang Mingliang Department of Mathematics Changshu Institute of Technology Changshu 215500 China Department of Applied Mathematics South China Agricultural University Guangzhou 510642 China

Let R(z) be a rational function of degree d ≥ 2. Then R(z) has at least one repelling periodic point of given period k ≥ 2, unless k = 4 and d=2, or k= 3 and d ≤ 3, or k=2 and d≤8. Examples show that all exception... 详细信息

关键词： rational function, iterate, fixed point, periodic point, repelling periodic point.

A novel dynamic proportional-type iterative learning control design for non-linear systems

在线全文

学校读者我要写书评

暂无评论

Journal of Control and Decision 2018年第3期5卷 265-276页

作者： Ming-fang chang Harbin Institute of Technology Shenzhen Graduate School ShenzhenP.R.China

This paper presents a model-free adaptive iterative learning control(ILC)scheme called a proportional-type ILC scheme for non-linear *** obvious characteristic of the proposed ILC scheme is that we can easily finish the ILC task just utilising the Lipschitz constant of the *** the proposed ILC scheme,the time-vary learning gain can be produced merely by input and output(I/O)***,the convergence conclusion can be expressed by the ranges of the pseudo-partial derivative and the learning *** actual operation,a reasonable and useful convergence condition by a constant is also provided for *** last,the effectiveness of the proposed ILC scheme is shown by simulations.

关键词： terative learning control proportional-type non-linear systems data-driven

Quark Condensate in the Strange Matter

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2003年第5期39卷 593-596页

作者： LU-chang-fang LUXiao-LU DepartmentofPhysics SichuanuniversityChengdu610064China DepartmentofPhysics SichuanuniversityChengdu610064China InstituteofTheoreticalPhysics AcademiaSinicaP.O.Box2735Beijing100080China

In a nonlinear chiral SU(3) framework, we investigate the quark condensate in the strange matter including and Λ, making use of chiral symmetry spontaneous breaking Lagrangian and mean-field approximation. The results show that the chiral symmetry is restored partially when the strange matter density increases and that plays a very important role in the strange matter which may approach the constituents of the neutron stars. In addition, we can find that the strange matter density where the π-condensate emerges leads to the ratio of the nucleon number to baryon number.

关键词： quark condensate chiral symmetry spontaneous breaking Lagrangian Hellmann-Feynman theory

A Negative Donor D^- in a Magnetic Field

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2006年第6期45卷 1117-1120页

作者： LIU chang XIE Wen-fang Department of Physics Faculty of Sciences Guangzhou University Guangzhou 510006 China

Using the method of numerical matrix diagonalization within the effective-mass approximation, we investigated a D^--center quantum dot system subjected to a Gaussian potential confinement. We obtain the dependence of binding energies of the ground-states of the D^--center on the depth of Gaussian potential and the magnetic field strength. The result shows clearly that the binding energies of the ground-states of the D^--center are rather sensitive to the depth of potential and the strength of magnetic field.

关键词： D^--center quantum dot Gaussian potential magnetic field

Spatial Distribution Pattern and Influencing Factors of Physical Bookstores of Large Cities:A Case Study of Three National Central Cities in Western China

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2023年第6期33卷 1082-1094页

作者： LIU Ruikuan LI Jiuquan chang fang MA Jiayao College of Urban and Environmental Sciences Northwest UniversityXi’an710127China School of Tourism&Research Institute of Human Geography Xi’an International Studies UniversityXi’an710128China

As cultural facilities,physical bookstore is an important part of urban *** by the development of social economy and the internet,physical bookstores also have become a combination of cultural space and tourism *** this case,it is necessary to explore the spatial characteristics and influencing factors of physical *** study uses Density-Based Spatial Clustering of Applications with Noise(DBSCAN),spatial analysis and geographical detectors to calculate the spatial distribution pattern and factors influencing physical bookstores in national central cities/municipality(hereafter using cities)in western *** on spatial data,population density,road density and other data,this study constructed a data set of the influencing factors of physical bookstores,consisting of 11 factors along 6 dimensions for 3 national central cities in western *** results are as follows:first,the spatial distribution pattern of physical bookstores in Xi’an,Chengdu,and Chongqing is *** spatial distribution of physical bookstores in Xi’an and Chongqing is from southwest to northeast and are relatively clustered,while those in Chengdu are relatively ***,the spatial distribution pattern of physical bookstores has been formed under the influence of different *** intensity and significance of influencing factors differ in the case ***,in general,the social factor,business factor,the density of research facilities,tourism factor and road density are the main driving factors in the three *** is a synergistic relationship between public libraries and physical ***,the explanatory power becomes stronger after the interaction between various *** Xi’an and Chengdu,the density of communities and the density of research facilities have stronger explanatory power for the dependent variable after interacting with other ***,in Chongqing,the traffic factors have stronger expl

关键词： spatial characteristics physical bookstores influencing factor Density-Based Spatial Clustering of Applications with Noise(DBSCAN) geographical detectors Xi’an Chengdu Chongqing

Influence of Quark Current Mass on Quark Condensate at Finite Temperature

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2013年第9期30卷 43-46页

作者： LU chang-fang LÜXiao-Fu Department of Physics Sichuan Agricultural UniversityYa’an 6250142 Department of Physics Sichuan UniversityChengdu 610064

Using the Dyson—Schwinger equation and perturbation theory,we define the quark condensate with the quark current mass at finite temperature,and compare the quark condensate at finite temperature for the quark current mass m=0 and m≠0,*** results show that the two-quark condensates have significantly different behaviors from the quark condensate in the chiral limit,and the quark current mass has a very important influence over the solution of the non-perturbative term.

关键词： quark perturbation finite

A novel D-type iterative learning control design for antilinear systems

在线全文

学校读者我要写书评

暂无评论

Journal of Control and Decision 2018年第4期5卷 338-345页

作者： Ming-fang chang Zhi-Chao Yu Harbin Institute of Technology Shenzhen Graduate School ShenzhenP.R.China

In this paper,a novel D-type iterative learning control(ILC)law is proposed for discrete-time antilinear *** D-type control law is different from the previous linear(nonlinear)D-type ILC *** main feature is that we take the conjugate of the(t+1)-th error to construct the proposed *** convergence proofs are given for their corresponding ILC schemes.

关键词： Antilinear system iterative learning control D-type learning law conjugation norm

Active set strategy of optimized extreme learning machine

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2014年第31期59卷 4152-4160页

作者： Xiao-Jian Ding Bao-fang chang Science and Technology on Information Systems Engineering Laboratory School of Computer and Information Engineering Henan Normal University

Extreme learning machine(ELM)has been introduced as a simple and efficient learning approach for regression and classification *** the optimization point of view,optimized ELM is equivalent to SVM,but with less constraints in the optimization formulation and random ELM *** paper introduces an active set based optimized ELM approach to solve bound constrained optimization problem in a straightforward way,which operates on a small working set of variables at each ***,the constrained problem can be eventually solved by an unconstrained algorithm,and this enables us to establish a global convergence *** approach requires less time for quadratic programming solving and provides better generalization *** addition,the proposed approach with much smaller number of nonbound support values is significantly faster than SVM with active set strategy for large training data set.

关键词：优化配方学习机有效集策略约束优化问题支持向量机 ELM 学习方法应用程序

Thermal atomic layer etching: Mechanism, materials and prospects

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2018年第6期28卷 667-675页

作者： chang fang Yanqiang Cao Di Wu Aidong Li National Laboratory of Solid State Microstructures Department of Materials Science and Engineering College of Engineering and Applied Sciences Collaborative Innovation Center of Advanced Microstructures Nanjing University

In the semiconductors and related industries, the fabrication of nanostructures and nanopatterns has become progressive demand for achieving near-atomic accuracy and selectivity in etching different materials, particularly in ultra-thin gate dielectrics and ultra-thin channels used in field-effect transistors and other nanodevices below 10 nm scale. Atomic layer etching(ALE) is a novel technique for removing thin layers of material using sequential and self-limiting reactions. Different from most ALE processes using plasma-enhanced or other energetic particles-enhanced surface reactions, thermal ALE realizes isotropic atomic-level etch control based on sequential thermal-drive reaction steps that are self-terminating and self-saturating. Thermal ALE can be viewed as the reverse of atomic layer deposition(ALD), both of which define the atomic layer removal and growth steps required for advanced semiconductor fabrication. In this review, we focus on the concept and basic characteristics of the thermal ALE in comparison with ALD. Several typical thermal ALE mechanisms including fluorination and ligand-exchange, conversion-etch, oxidation and fluorination reactions are intensively *** pros and cons of thermal ALE, plasma ALE, and traditional plasma etching are compared. Some representative materials and their typical thermal ALE processes are summarized. Finally, the outlook and challenges of thermal ALE are addressed.

关键词： Thermal atomic layer etching Atomic layer deposition Self-limiting Reaction mechanism Atomic-scale precision