检索结果-南通市图书馆

金属学报 1982年第6期18卷 735-745页

作者：左秀忠东北工学院

本文研究了Fe-Al合金相及相变与价电子态之间的关系,并且揭示了相转变的机理。对磁矩和范性随成分和热处理制度而变化的规律做了理论上的解释。特别是,计算所得到的Bohr磁子数与实验值颇为吻合。

关键词： Fe-Al 晶格电子晶种轻子价电子结构热处理制度合金相金相相组成 Al 超结构相

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

多频驱动的近哈密顿系统的Hopf分岔

振动与冲击 2012年第19期31卷 40-47,85页

作者：符五久东华理工大学理学院江西抚州344000

将无扰闭轨道变量变换到作用-角变量,再将微扰变量在无扰闭轨道附近展开,获得了有微扰的作用-角变量一级近似表达式。以无扰闭轨道的周期为采样时间,用作用-角变量表达式建立了二维多频驱动的Poincar'e映射,由其中的作用变量映射定义了... 详细信息

将无扰闭轨道变量变换到作用-角变量,再将微扰变量在无扰闭轨道附近展开,获得了有微扰的作用-角变量一级近似表达式。以无扰闭轨道的周期为采样时间,用作用-角变量表达式建立了二维多频驱动的Poincar'e映射,由其中的作用变量映射定义了多频驱动的次谐Melnikov函数,并用该函数,给出了Hopf分岔条件。并应用到多频驱动的Duffing-Van der pol系统中,导出了该系统的Hopf分岔条件。按分岔条件取参数,对三频驱动的Duffing-Van der pol方程进行了数值模拟,无一例外地均出现了Hopf分岔。

关键词：多频驱动近哈密顿系统 Melnikov函数方法 Hopf分岔

ENDOR AND ESR STUDIES OF RADICALS FORMED IN FRIEDEL-CRAFTS REACTIONS

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 1991年第11期34卷 1296-1303页

作者：桑鸿汪汉卿陈涛刘旭勤Center of Analysis and Research east China University of Chemical technology Shanghai 200237 PRC Lanzhou institute of Chemical Physics Academia Sinica Lanzhou 730000 PRC Center of Analysis and Research East China University of Chemical Technology

The present study deals with the study of some Friedel-Crafts alkylating system and the accurate measurement of hyperfine coupling constants by ESR and ENDOR techniques. The results indicate that the observed ESR spectra are due to polycyclic aromatic radical cations formed from their parent *** is suggested that benzyl halides produced in the Friedel-Crafts alkylating reaction undergo Scholl condensation reaction to give polycyclic aromatic hydrocarbons, which were converted into the corresponding polycyclic aromatic radical cations in the presence of aluminum chloride.

关键词： radical cations ESR ENDOR Friedel-Crafts reactions.

在线全文

学校读者我要写书评

暂无评论

集合锐积的组合算法及其应用

计算机学报 1989年第5期12卷 335-342页

作者：余庆健华东工学院

本文提出计算在n维布尔空间上定义的一多维体对另一多维体集合锐积的组合算法。这个方法将该锐积计算简化为寻找定义在n′维(n′≤n)布尔空间的2n′个n′-1维体的极小有效组合集问题,而后者又等价为寻找一个行相关矩阵的极小有效列覆盖... 详细信息

本文提出计算在n维布尔空间上定义的一多维体对另一多维体集合锐积的组合算法。这个方法将该锐积计算简化为寻找定义在n′维(n′≤n)布尔空间的2n′个n′-1维体的极小有效组合集问题,而后者又等价为寻找一个行相关矩阵的极小有效列覆盖集的问题。该算法保证所得的均为质多维体,且有较高的计算效率,它还为锐积运算更有效地运用于逻辑最小化的过程创造了条件。

关键词：集合锐积组合算法逻辑设计

The geodetic numbers of graphs and digraphs

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2007年第8期50卷 1163-1172页

作者： Chang-hong LU~(1,2) 1 Department of Mathematics,east China Normal University,Shanghai 200062,China 2 institute of Theoretical Computing,east China Narnal University,Shanghai 200062,China Department of Mathematics East China Normal University Shanghai China institute of Theoretical Computing East China Narnal University Shanghai China

For every two vertices u and v in a graph G, a u-v geodesic is a shortest path between u and v. Let I(u, v) denote the set of all vertices lying on a u-v geodesic. For a vertex subset S, let I(S) denote the union of all I(u, v) for u, v ∈ S. The geodetic number g(G) of a graph G is the minimum cardinality of a set S with I(S) = V (G). For a digraph D, there is analogous terminology for the geodetic number g(D). The geodetic spectrum of a graph G, denoted by S(G), is the set of geodetic numbers of all orientations of graph G. The lower geodetic number is g ?(G) = minS(G) and the upper geodetic number is g +(G) = maxS(G). The main purpose of this paper is to study the relations among g(G), g ?(G) and g +(G) for connected graphs G. In addition, a sufficient and necessary condition for the equality of g(G) and g(G × K 2) is presented, which improves a result of Chartrand, Harary and Zhang.

关键词： convex set digraph distance geodesic geodetic number 05C12 05C20

Introspective,Client-Server technology

在线全文

学校读者我要写书评

暂无评论

Introspective,Client-Server Technology

Study on Revising Running Parameter in Embedded System and its Application

2012 National Conference on Information technology and Computer Science

作者： Ma yanchun North China institute and technology Yanjiao Beijing-east,China Pan jixin North China institute and technology Yanjiao Beijing-east,China

The World Wide Web and information retrieval systems,while important in theory,have not until recently been considered *** our research,we prove the private unification of 2 bit architectures and congestion *** construct an electronic tool for developing extreme programming （Sikhs）,which we use to prove that compilers can be made realtime,knowledge-based,and homogeneous.

关键词： Introspective

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

微计算机信息 2008年第17期 85-86+82页

作者： (1east China institute of technology (Nanchang Campus) Nachang 330013 China)TAN Hai CHEN Hong-mao ZHOU Xin-qin XIONG Guo-quan

The article expounds the technology that UPD protocol is applied when revising configured the parameter remotely in embedded system. It also introduces the process in realizing the system with the corresponding codes in detail and related communication protocols. Finally gives a example how the research being applied for the "home- school- communication"system。

关键词： Protocol Parameter UDP Home-school-communication

Numerical Investigation of Noise from an Over-Expanded Nozzle

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Numerical Investigation of Noise from an Over-Expanded Nozzl...

A PRELIMINARY INVESTIGATION OF THE CONTROL OF SEPARATED FLOW BY MEANS OF EXCITATION

The 4th Across-strait Workshop on Shock Wave/Vortex Interaction

作者： Cheng-Jie Wang~*,Shen-Min Liang~+ Department of Computer Application Engineering,far east University of technology

Nozzles are usually used to accelerate a flight *** an under-expanded nozzle,an oblique shock wave issued from the nozzle exit is necessary in order to adjust the relative low pressure at the exit to the ambient ***,a complicated flow structure may occur such as a shock-shock interaction,a shock/shear layer interaction,expansion waves/shear layer interaction,and shock/vortex interaction,***,the radiated noise due to these interactions is worthwhile to investigate for the nozzle *** this study,a high-resolution compressible Navier-Stokes solver is used to analyze the noise problem associated with an under-expanded *** the noise analysis,a detailed flow field downstream the nozzle is first numerically investigated.

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 1993年第4期 239-243页

作者： Xu Cheng (east China institute of technology,Nanjng,210014) Zhang Shi-ying,Zhou Ming-de (Nanjing University of Aeronautics and Astronautics,Nanjing,China,210016)

Force measurements combined with flow visualization are used to investigate the controlof two dimensional leading-edge separation by means of flap oscillation. It is foundthat the results of control are related to the model natural flow patterns. When the naturalflow pattern is a closed separation bubble, the excitation causes a lift loss. A reduction ofreattachment length and a reduction of the drag of the model can be achieved by properfrequency excitation. The most effective Strouhal number range based on the reattachmentlength and the main stream velocity for drag reduction is 3～5. When the natural flow patternis full separation, proper frequency excitation changes the flow field into a closed separationbubble and a lift increment is achieved. The most effective Strouhal number rangebased on the chord of the model and main stream velocity for lift increment is 0.70～2.5.

关键词： Re length A PRELIMINARY INVESTIGATION OF THE CONTROL OF SEPARATED FLOW BY MEANS OF EXCITATION

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

稀土元素改善工具钢切削性能的研究

钢铁 1982年第5期17卷 55-60页

作者：孙荣耀郝士明东北工学院

本文对含硫易切钢中加入稀土元素所形成的稀土硫化物夹杂物对钢切削性能的影响,及其机理的实验表明,稀土和硫在钢中形成的夹杂物主要是Ce2S3和Ce2SO2夹杂物.这两种夹杂物的硬度、熔点及其球状的几何外形,对钢的切削加工有利,并改善了含... 详细信息

本文对含硫易切钢中加入稀土元素所形成的稀土硫化物夹杂物对钢切削性能的影响,及其机理的实验表明,稀土和硫在钢中形成的夹杂物主要是Ce2S3和Ce2SO2夹杂物.这两种夹杂物的硬度、熔点及其球状的几何外形,对钢的切削加工有利,并改善了含硫易切钢的横向机械性能.

关键词：夹杂物周围熔点空洞钢材条状熔解温度切削性能易切钢稀土元素 ⅢB族元素