Global Synchronization of Discrete-Time Dynamical Network With a Directed Graph

We investigate synchronization of linearly coupled map lattices with asymmetric and irreducible coupling matrices. In terms of graph terminology, the coupling matrix represents a directed graph. In case the uncoupled map satisfies Lipschitz conditions, a criterion of global synchronization of the linearly coupled map lattices is derived. With this criterion, we investigate how synchronizability depends on the coupling matrix as well as graph topology. Furthermore, we also prove that a directed graph can synchronize some chaotic map if and only if the graph contains a spanning tree     

欧洲中世纪大学的特色

诞生于欧洲12世纪的中世纪大学是现代大学的前身,现代大学所具有的特色正是继承于中世纪大学的特色.现代大学不仅仅继承了大学这个名称,还继承了中世纪大学的基本组织结构、学位制度、自治、学术自由及教学等等.现代大学也在走向回归之路,中世纪大学所独具的国际性经过几百年的沉沦又逐渐为现代大学接受和吸收.因此,对中世纪大学的本质特色和时代特色进行探索为研究现代大学特色的形成与发展提供历史根据和理论支持,有利于现代大学更好地走特色道路,以提供优质教育质量赢得来自国际和国内的竞争,以大学独特吸引力获得世界瞩目和良好的声誉.     

Observation of Robust Néel Skyrmions in Metallic PtMnGa

Over the past decade the family of chiral noncollinear spin textures has continued to expand with the observation in metallic compounds of Bloch-like skyrmions in several B20 compounds, and antiskyrmions in a tetragonal inverse Heusler. Néel like skyrmions in bulk crystals with broken inversion symmetry have recently been seen in two distinct nonmetallic compounds, GaV₄S₈ and VOSe₂O₅ at low temperatures (below ≈13 K) only. Here, the first observation of bulk Néel skyrmions in a metallic compound PtMnGa and, moreover, at high temperatures up to ≈220 K is reported. Lorentz transmission electron microscopy reveals the chiral Néel character of the skyrmions. A strong variation is reported of the size of the skyrmions on the thickness of the lamella in which they are confined, varying by a factor of 7 as the thickness is varied from ≈90 nm to ≈4 µm. Moreover, the skyrmions are highly robust to in-plane magnetic fields and can be stabilized in a zero magnetic field using suitable field-cooling protocols over a very broad temperature range to as low as 5 K. These properties, together with the possibility of manipulating skyrmions in metallic PtMnGa via current induced spin–orbit torques, make them extremely exciting for future spintronic applications.     

获各琦铜矿矿房回采方案优化比较

西部铜业有限公司现在已经成功使用了胶结充填采矿法。采矿实践发现,使用浅孔留矿法回采完间柱,充填后,再回采矿房时,用上向水平分层充填采矿法比用分段空场嗣后充填采矿法更加合理。通过分析对比上向水平分层充填采矿法和分段空场嗣后充填的各项技术经济指标,得出使用上向水平分层充填采矿法回采富铜矿体矿房更优化的结论,从而为其它矿山回采类似矿房提供借鉴。     

广东科学中心建筑节能技术应用

广东科学中心作为广州市21世纪标志性建筑之一采用了多项节能技术,包括自然采光、中庭自然通风与遮阳技术、围护结构节能、空调系统节能、照明系统节能、太阳能光伏发电站——太阳能风帆、光电幕墙技术、雨水回渗与屋面集水系统等。相比节能标准实施前实现了60%的总体节能率目标,满足绿色施工要求。     

充填采矿法在获各琦铜矿的应用

获各琦铜矿原采用浅孔留矿法。通过分析获各琦铜矿的开采技术条件,比较浅孔留矿法和上向水平分层充填采矿法,对矿山采矿方法进行优化。最终达到合理开采矿产资源和提高经济效益的目的,为类似矿山提供借鉴。     

获各琦铜矿上向水平分层充填采矿方法的完善

上向水平分层充填采矿法已在获各琦铜矿成功应用。通过近两年的采矿实践,发现获各琦铜矿深部中段CuI矿体中的矿岩较破碎,若继续采用原有充填采矿法的采场结构参数,很难满足正常生产的需求。因此,对采场结构参数进行调整和完善。通过分析对比各项技术经济指标,发现调整后的上向水平分层充填采矿法的采场结构参数更优化,从而为其它矿山提供借鉴。     

基于FoxPro的采场管理系统设计与实现

在大型矿山中，同时生产的采场个数多，采场信息量大，进行手工管理时工作量大，效率低，本文结合矿山生产管理实际和日常工作信息需求，运用Visual FoxPr06．0设计了采场管理系统，该系统具有开放性、实用性、可靠性、兼容性等特点，使用采场管理系统是新型办矿模式下采场科学管理的有效手段之一。     

Comments on “Improved Sufficient Conditions for Global Asymptotic Stability of Delayed Neural Networks”

In this note, we point out that the results given in the paper by Wu and Cui (2007) can be obtained by using the results given in Lu (2003). Moreover, the results given in the second paper are much stronger under less restrictive conditions.      

可编程逻辑器件在HP82000系统上测试

文中介绍了电擦除可编程逻辑器件在ＨＰ８２０００系统上的功能测试及参数测试。