检索结果-南通市图书馆

A note on n-edge chromatic number

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1997年第23期42卷 1952-1954页

作者： SUN Liang and ZHANG Zhongfu1. Department of applied mathematics, Beijing {2. of Technology, Beijing 100081, china 2. institute of applied mathematics, lanzhou {2. of Railway, lanzhou 730070, china Department of applied mathematics Beijing Institute of Technology Beijing 100081 China

ALL graphs appearing in this note are simple. A graph with p vertices and q edges will becalled a (p, q )-graph. The maximum degree of G is denoted by Δ(G).Let n≥2.be an integer. The n-edge chromatic number X_n (G) of a simple graph G is theminimum cardinality of a set of colors with which one can assign the colors to the edges of Gsuch that the edges on a path of length less than or equal to n receive different *** aim of this note is to explore the bounds for X’_n (G) and X’_n (G) + X’_n (G). It is

关键词： graph complement n-edge chromatic number.

D(β)-vertex-distinguishing total coloring of graphs

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2006年第10期49卷 1430-1440页

作者： ZHANG Zhongfu,LI Jingwen,CHEN Xiang’en,YAO Bing, WANG Wenjie & QIU Pengxiang institute of applied Mathematic, {2. jiaotong University, lanzhou 730070, china College of mathematics and Information Science, Northwest Normal University, lanzhou 730070, china College of Information and Electrical Engineering, {2. jiaotong University, lanzhou 730070, china institute of applied Mathematic Lanzhou Jiaotong University Lanzhou 730070 China College of mathematics Information Science Northwest Normal University Lanzhou 730070 China College of Information Electrical Engineering Lanzhou Jiaotong University Lanzhou 730070 China

A new concept of the D(β)-vertex-distinguishing total coloring of graphs, i.e., the proper total coloring such that any two vertices whose distance is not larger than β have different color sets, where the color set of a vertex is the set composed of all colors of the vertex and the edges incident to it, is proposed in this paper. The D(2.-vertex-distinguishing total colorings of some special graphs are discussed, meanwhile, a conjecture and an open problem are presented.

关键词： graph, total coloring, D(β)-vertex-distinguishing total coloring, D(β)-vertexdistinguishing total chromatic number.

A computer simulation of nucleation and growth of thin films

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2004年第4期47卷 442-451页

作者： ZHENG Xiaoping1,ZHANG Peifeng2.HE Deyan2.LIU Jun2. MA Jiantai3 1. Key Laboratory of Opto-Electronic Technology and Intelligent Control, Ministry of Education, lanzhou jiaotong University,{2., china 2. School of Physical Science and Technology, lanzhou University, lanzhou 730000, china 3. School of Chemistry and Chemistry Engineering, lanzhou University, lanzhou 730000, china 1. Key Laboratory of Opto-Electronic Technology and Intelligent Control Ministry of Education Lanzhou Jiaotong University 730070 Lanzhou China 2. School of Physical Science and Technology Lanzhou University 730000 Lanzhou China 3. School of Chemistry and Chemistry Engineering Lanzhou University 730000 Lanzhou China

A three-dimensional kinetic Monte Carlo technique has been developed for simulating the nucleation and growth of thin films. This model involves incident atom attachment, surface diffusion of the atoms on the growing surface and atom detachment from the growing surface. It takes some new effects into account, such as a significant improvement in calculation of activation energy for the atom diffusion, which renders the model more reasonable. In addition three optimum temperatures and the consistency of their dependence on deposition rate have been found out; the dependence of the surface roughness and relative density on the deposition rate has been discussed; and the approximation of freezing neighbour atoms and periodic boundary conditions has been applied.

关键词： Monte Carlo, thin film, nucleation, surface roughness, relative density.

Multifield coupling model and its applications for pile foundation in permafrost

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2005年第7期48卷 968-977页

作者： WU Yaping1,2. ZHU Yuanlin2. GUO Chunxiang1, SU Qiang1 & MA Wei2.1. School of Civil Engineering, lanzhou jiaotong University,{2., china 2. State Key Laboratory of Frozen Soil Engineering, Cold and Arid Regions Environmental and Engineering Research institute, Chinese Academy of Sciences, lanzhou 730000, china School of Civil Engineering Lanzhou Jiaotong University Lanzhou 730070 China State Key Laboratory of Frozen Soil Engineering Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China

Importing the interface element which links the frozen soil base with concrete piles and considering the couplings of stress field, temperature field and moisture field, this paper es- tablishes the nonlinear visco-elastic plastic finite element model of pile-soil. For a practical bridge structure the stress field and displacement field of single pile in freezing process are calculated. This paper emphatically studies the process of the tangential frost heave stress field, freezing stress field and displacement field varying with time, and ulteriorly studies time variation process of single pile carrying capacity in freezing process.

关键词： permafrost pile foundation freezing process multifield coupling analysis model.

Theory of truth degrees of propositions in the logic system Ln^＊

在线全文

学校读者我要写书评

暂无评论

Science in china(Series F) 2006年第4期49卷 471-483页

作者： LI Jun1,2.& WANG Guojun1,3 1. institute of mathematics, Shaanxi Normal University, Xi’an 710062.{2. 2. School of Sciences, lanzhou University of Technology, lanzhou 730050,{2. 3. Research Center for Science, Xi’an jiaotong University, Xi’an 710049,{2. 1. institute of mathematics Shaanxi Normal University Xi’an 710062 China 2. School of Sciences Lanzhou University of Technology Lanzhou 730050 China 3. Research Center for Science Xi’an Jiaotong University Xi’an 710049 China

By means of infinite product of uniformly distributed probability spaces of cardinal n the concept of truth degrees of propositions in the n-valued generalized Lu- kasiewicz propositional logic system Ln^＊ is introduced in the present paper. It is proved that the set consisting of truth degrees of all formulas is dense in [0,1], and a general expres- sion of truth degrees of formulas as well as a deduction rule of truth degrees is then obtained. Moreover, similarity degrees among formulas are proposed and a pseudo-metric is defined therefrom on the set of formulas, and hence a possible framework suitable for developing approximate reasoning theory in n-valued generalized Lukasiewicz propositional logic is established.

关键词： truth degree similarity degree approximate reasoning.

Improvements on radiation-hardened performance of static induction transistor

在线全文

学校读者我要写书评

暂无评论

Science china(Information Sciences) 2010年第5期53卷 1089-1096页

作者： WANG YongShun 1 , LUO XianLiang 1 , LI HaiRong 2., WANG ZiTing 1 , WU Rong 1 , ZHANG CaiZhen 2.& LI SiYuan 2.1 School of Electronic and Information Engineering, lanzhou jiaotong University,{2., china 2.institute of Microelectronics, School of Physical Science and Technology, lanzhou University, lanzhou 730000, china 1. School of Electronic and Information Engineering Lanzhou Jiaotong University Lanzhou 730070 China2. Institute of Microelectronics School of Physical Science and Technology Lanzhou University Lanzhou 730000 China

The radiation-hardened performances of static induction transistor (SIT) have been studied in depth in this paper. The effects of radiation of electron beam on the I-V characteristics, carrier distribution and potential distribution in the channel of SIT have been represented. A large number of electron-hole pairs are generated in the depletion region of reversely biased gate-channel PN junction. The radiation-generated electrons drift towards the drain region at high positive potential, while generated holes flow into gate region biased to the lowest potential. With the accumulation of holes in gate region, the gate potential is boosted, resulting in a decrease in the height of potential barrier in channel, and an increase in drain current. I-V characteristics of SIT in the presence of radiation have been theoretically derived, and compared with experimental results. With the increase in thickness of epitaxial layer, the radiation-hardened capability of SIT is continuously improved until the optimum thickness of 2. μm is reached. The optimum matching relationship among geometric, material and technological parameters has been represented to acquire excellent radiation-hardened performances of SIT.

关键词： static induction transistor radiation-resistant potential barrier electron beam radiationgenerated carriers

On the periodic solutions of a type of differential-iterative equations

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第3期43卷 204-206页

作者： GE Weigao 1, LIU Zhengrong 2.and YU Yuanhong 3 1. Department of applied mathematics, Beijing {2. of Technology, Beijing 100081, china 2. Department of mathematics, Yunnan University, Kunming 650091, china 3. institute of applied mathematics, C Department of applied mathematics Beijing Institute of Technology Beijing China Department of mathematics Yunnan University Kunming China institute of applied mathematics Chinese Academy of Sciences Beijing China

Sufficient conditions for the existence of periodic solutions to a type of nonautonomous differential_iterative equations are given.

关键词： differential_iterative equation periodic solution fixed point.

The characteristic spectral lines of target atoms in the impact of^(40)Ar^(q+)ions on metal surfaces

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2004年第6期47卷 729-736页

作者： ZHANG Xiao’an1,2.ZHAO Yongtao1,2.LI Fuli1,YANG Zhihu2.XIAO Guoqing2.& ZHAN Wenlong2.1.Department of applied Physics,Xi’an jiaotong University,Xi’an 710049,{2. 2.institute of Modern Physics,Chinese Academy of Sciences,lanzhou 730000,{2. Department of applied Physics Xi'an Jiaotong University Xi'an 710049 China institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China

We report the measured results of the 2.0 nm—1000 nm characteristic spectral lines of target atoms when highly charged ions40Ar q+(6≤q≤14) with the same kinetic energy and40Ar6+ with different kinetic energies are incident upon Al, Ti, Ni, Ta and Au surfaces, respectively. The results for12.Xe6+,12.Xe10+ and12.Xe15+ with the same kinetic energy (150 keV) incident upon a Ta surface are also reported. These results show that when the projectile and target are properly selected (40Ar12. impinges on Al,12.Xe6+ impinges on Ta), the spectral intensity of characteristic spectral lines of the target atom is effectively enhanced, and is not strongly dependent on the kinetic energy of the incident ions.

关键词： highly charged ion, hollow atom, characteristic spectrum, spectral intensity.

Existence of the solutions and the attractors for the large-scale atmospheric equations

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2006年第6期49卷 650-660页

作者： HUANG Haiyang1 & GUO Boling2.1. Department of mathematics, Beijing Normal University, Beijing 100875, china 2. {2. of applied Physics and Computational mathematics, Beijing 100080, china 1. Department of mathematics Beijing Normal University Beijing 100875 China 2. institute of applied Physics and Computational {2. Beijing 100080 China

In this paper, firstly, the proper function space is chosen, and the proper expression of the operators is introduced such that the complex large-scale atmospheric motion equations can be described by a simple and abstract equation, by which the definition of the weak solution of the atmospheric equations is made. Secondly, the existence of the weak solution for the atmospheric equations and the steady state equations is proved by using the Galerkin method. The existence of the non-empty global attractors for the atmospheric equations in the sense of the Chepyzhov-Vishik’s definition is obtained by constructing a trajectory attractor set of the atmospheric motion equations. The result obtained here is the foundation for studying the topological structure and the dynamical behavior of the atmosphere attractors. Moreover, the methods used here are also valid for studying the other atmospheric motion models.

关键词： atmosphere equations, weak solution, trajectory attractor, global attractor, equilibrium.