基于网络处理器的RPR综合业务接入平台的设计

弹性分组环(RPR)是一种新的城域网技术,文章提出了用网络处理器IXP1 200构建RPR综合业务接入平台的设计方案,并重点讲述了其中微引擎部分的软件设计.     

双积分A/D转换器的量程自动转换

介绍了一种双积分式A/D转换器在宽范围量程测量中的自动量程转换技术.在测量仪表的输入通道中,用计数器对双积分型A/D转换器本身所固有的过量程/欠量程信号计数,计数器的输出作为量程编码去控制量程的选择,同时又是送到CPU的量程指示信号.该技术扩大了A/D转换量程,提高了精度,设计简单,工作可靠.     

The Possibilities of Community OR in a Third World Country

This paper shows a few possibilities for the application of Community OR in a Third World country based on experience in Venezuela. These possibilities are discussed in a framework of the relationship between the state and community organizations. Emphasis lies in showing that Community OR in Venezuela requires a deep critical commitment to emancipation in order to help community organizations develop in a rather hostile environment. Lastly, results in dealing with community organizations in Venezuela using the Interpretive Systemology approach are presented.     

Community OR — Five Years of Organised Activities and Beyond

What has become known as Community Operational Research has been around in the UK for many years. The election of Jonathan Rosenhead as President of the UK OR Society in 1986–87 was the catalyst for bringing together and expanding activities which had been carried out largely by individuals working in isolation on a voluntary basis. The following five years have seen the establishment of the Community OR Unit at Northern College, the Centre for Community OR at Hull University and the Community OR Network, which supports the activities of volunteer OR workers across the UK. This paper reviews the range and types of work which have been undertaken by various practitioners. An assessment of the success of community OR is made and a number of issues which have arisen are discussed. Finally, given the diverse nature of community OR, its practice and practitioners, there is some discussion about the future of the area.     

Channelling studies on the lattice location of B atoms in graphite

In order to obtain information on the lattice location of B atoms in graphite, channelling experiments have been performed at room temperature with a proton beam of an energy of 0.65-0.77 MeV for the 〈0 0 0 1〉 axial channel in highly oriented pyrolytic graphite (HOPG) crystals doped with 0.32 at.% B. The B atoms are detected by measuring α-particles which are emitted as a result of a nuclear reaction ¹¹B(p,α)αα. It is clearly demonstrated that most of B atoms are shadowed behind the 〈0 0 0 1〉 C atomic rows. Taking account of the already reported experimental results on a change of lattice parameters by B-doping, it is concluded that most of B atoms are located at substitutional sites. It is also observed that B-doping introduces lattice strain on the c-plane. In addition, the presence of a small portion of interstitial B atoms is suggested.     

广义AND／OR图的自底向上的启发式搜索算法BHAO

本文首先根据三角模概念，定义了一类新的更具普遍意义的广义ＡＮＤ／ＯＲ图．根据新定义的启发式函数ｈ（ｎ，ｘ）以及广义ＡＮＤ／ＯＲ图的最佳解树之所有子树亦是最佳子解树的原理，提出了广义ＡＮＤ／ＯＲ图的自底向上的启发式搜索算法ＢＨＡＯ．文中证明了算法ＢＨＡＯ的可采纳性．本文还提出了两类新的启发式函数的单调限制概念，并据此研究了算法ＢＨＡＯ的单调限制性质，研究了两个ＢＨＡＯ算法间的比较性质．     

EBSD investigation of SiC for HTR fuel particles

Electron back-scattering diffraction (EBSD) can be successfully performed on SiC coatings for HTR fuel particles. EBSD grain maps obtained from thick and thin unirradiated samples are presented, along with pole figures showing textures and a chart showing the distribution of grain aspect ratios. This information is of great interest, and contributes to improving the process parameters and ensuring the reproducibility of coatings.     

Thermodynamics of Fe-Cu alloys as described by a classic potential

The Fe-Cu system is of relevance to the nuclear industry because of the deleterious consequences of Cu precipitates in the mechanical properties of Fe. Several sets of classical potentials are used in molecular dynamics simulations studies of this system, in particular that proposed by Ludwig et al. [M. Ludwig, D. Farkas, D. Pedraza, S. Schmauder, Model. Simul. Mater. Sci. Eng. 6 (1998) 19]. In this work we extract thermodynamic information from this interatomic potential. We obtain equilibrium phase diagram and find a reasonable agreement with the experimental phases in the regions of relevance to radiation damage studies. We compare the results with the predicted phase diagram based on other potential, as calculated in previous work. We discuss the disagreements found between the phase diagram calculated here and experimental results, focusing on the pure components and discuss the applicability of these potentials. Improved potentials, primarily for the pure components, should be developed to account for proper phase stability in the solid phase up to melting. Finally we suggest an approach to improve existing potentials for this system.     

S7-1200PLC在物料混合控制系统中的应用

针对传统的物料混合装置控制精度低、可靠性不足等问题,提出采用西门子S7-1200 PLC和触摸屏来控制与监视物料混合系统的工作过程,实现两种物料从进料、搅拌到出料控制等功能。控制单元基于TIA博途全集成自动化软件平台编制梯形图。触摸屏作为上位机实现人机界面交互的功能,经试验表明,采用模块化程序设计软件代替传统的继电控制,各控制阀能精确实现开启、关闭功能,液位升降模拟过程真实、精准,系统运行稳定,不仅可大大提高生产效率,而且可降低系统故障率。     

A novel design of 8-bit adder/subtractor by quantum-dot cellular automata

Application of quantum-dot is a promising technology for implementing digital systems at nano-scale. QCA supports the new devices with nanotechnology architecture. This technique works based on electron interactions inside quantum-dots leading to emergence of quantum features and decreasing the problem of future integrated circuits in terms of size. In this paper, we will successfully design, implement and simulate a new full adder based on QCA with the minimum delay, area and complexities. Also, new XOR gates will be presented which are used in 8-bit controllable inverter in QCA. Furthermore, a new 8-bit full adder is designed based on the majority gate in the QCA, with the minimum number of cells and area which combines both designs to implement an 8-bit adder/subtractor in the QCA. This 8-bit adder/subtractor circuit has the minimum delay and complexity. Being potentially pipeline, the QCA technology calculates the maximum operating speed.