三次谐波检测无刷直流电机转子位置的研究

论述了一种用三次谐波检测转子位置的新方法。与传统的反电动势法检测转子位置相比较，三次谐波法实现简单，可检测速度范围更宽，不需要深度滤波。文中抛弃了将三次谐波直接输入DSPA／D口的传统做法，而是将反映三次谐波相位信息的方波输入DSP的I／O口，利用DSP强大的数据处理功能，提出了用软件实现数字锁相功能和对换相时刻的准确估计，去除了传统的硬件积分方法；提出用模拟相电压代替传统的端电压作为辅助检测信号；从而简化了硬件电路，提高了转子位置估计的精度和可靠性。实际试验表明，这种方法能够准确而快速的估计转子位置，动静态特性良好，整个系统结构紧凑，可靠性高。     

论坚持党的先进性

通过对坚持党的先进性是我们党战胜一切困难，最终获得政权的制胜法宝；是推动社会主义建设和国家昌盛的强大动力；坚持党的先进性，必须与时俱进，勇于理论创新；必须注重发挥其对历史进程的推动作用；必须深入持久地开展好党员先进性教育活动等方面的论述，明确回答了为什么要坚持党的先进性，如何坚持党的先进性。     

校园局域网中二、三层交换技术的应用

文章以长沙通信学院校园局域网为例，介绍校园网用户是如何通过网络交换设备实现相互通信的工作过程。     

一种基于三阶中心矩的图像边缘检测方法

利用像素邻域的三阶中心矩,可以提取图像边界。根据边缘图像灰度的众数,边缘强度图像的二值化变得非常简单,不需要手工交互。利用中国数字化虚拟人数据进行实验,结果表明,应用这种基于三阶中心矩的新方法来检测边缘的效果良好。     

浅谈三层交换技术

网络交换机和路由器有机结合的三层交换技术具有许多优良特性,可给校园网和教育网的建设带来许多便利.因而介绍其概念、原理、应用.     

Less cyber,more café: Enhancing existing small businesses across the digital divide with ICTs

About 10% of the world has access to information and communication technologies (ICTs). Telecenters and cyber cafés are one prevalent way to increase access. This paper suggests increasing access through currently existing, local businesses where people already gather and where proprietors already posses existing business relationships with suppliers and customers. This paper questions the prevailing emphasis on the “cyber'' characteristics of access, e.g., computing and internet access as is currently known, and attempts to refocus the conversation by considering computing and access in the context of the “café,” e.g., as public life in the sense of Habermas, which permits an in situ evolution of relevant access. This analysis is based on extant literature and direct ethnographic research in several public places in six countries. We offer example design perspectives based on a reflection of “third places” as inspiration for appropriate innovation in the provision of computing and communications. © 2005 Wiley Periodicals, Inc.     

Exploring heterogeneous growth of wind energy across Germany

Expansion of renewable energies in Germany is strongly associated with decentralization of energy provision. In the case of wind energy there are especially strong regional-level spatial, technical, economic, and social ramifications of this energy source. In addition to differing natural conditions and the strong push from the federal feed-in tariffs, policies and initiatives at the state, county, and municipal level need to be considered when explaining the pattern of wind energy expansion across time and space and to improve the coordination of multi-level energy policies. This paper uses panel regressions at the level of German counties from 2001 to 2012 to explore the growth of wind power capacity. Based on the estimates obtained, we then analyze counterfactual scenarios in which factors influenced by the regional (county) level are varied individually. Our focus is on party policy preferences and coalitions on the one hand, and the unemployment rate on the other. While strict causality is difficult to establish, our results reveal heterogeneous incentives between states, within states, and between different county types.     

Influence of Oxide Morphologies on Galvanizability of Third Generation Automotive Steel

Focusing on improving the galvanizability of the third generation automotive steel, the effect of surface ox ide morphologies on the galvanizability was studied. The results show that the surface oxide types of sample steels by X ray photoelectron spectroscopy （XPS） analysis after annealing in different conditions are the same. Only MnO, MnO2 and Cr2O3 were detected and no complex oxide exists on the surface. Morphologies of surface oxides can greatly influence the galvanizability of the third generation automotive steel. Nodule-like oxide surface can contribute to better wettability and inhibition layer than vitreous film like oxide surface. Galvanized panels of nodule-like oxide surface steels only show pinhole sized bare spots, while panels galvanized from vitreous film-like oxide surface steels reveal larger areas of bare spots and uncoated areas. Inhibition layer observed in galvanized panels of nodule-like oxide surface steels is compact but not homogeneous; some inhibition layer grains are fine, and others are coarse, while the inhibition layer grains of panels galvanized from vitreous film-like oxide surface steels have a non-compact morphology with some particularly fine equiaxed crystals which developed deficiently.     

Variable neighborhood search for the bi-objective post-sales network design problem: A fitness landscape analysis approach

Post-sales services are important markets in electronics industry due to their impact on marginal profit, market share, and their ability to retain customers. In this study, designing a multi-product four-layer post-sales reverse logistics network operated by a 3PL is investigated. A bi-objective MILP model is proposed to minimize network design costs as well as total weighted tardiness of returning products to customers. To solve the proposed model, a novel multi-start variable neighborhood search is suggested that incorporates nine neighborhood structures and three new encoding–decoding mechanisms. In particular, a fitness landscape measure is employed to select an effective neighborhood order for the proposed VNS. Extensive computational experiments show the effectiveness of the proposed heuristic and the three encoding–decoding mechanisms. The proposed method finds significantly better Pareto optimal sets in comparison with the original Priority method based on the number and the quality of obtained Pareto optimal solutions. In addition, it shows high efficiency by finding near-optimal solutions for the single objective versions of the problem.     

广西壮族自治区土地整治工程质量第三方检测探索

以施工单位自检为主的检测模式不能完全保证工程质量，广西壮族自治区探索第三方检测新模式，以更好服务于土地整治工程建设。本文阐述了土地整治工程质量第三方检测背景、思路、技术措施及其在土地整治工程中的作用。