变电站三维仿真系统的应用实践

随着国家发展战略中提出智能电网,智能变电站的建设日新月异,从而对电力系统人才的综合素质提出了更高的要求。介绍了一种用于教学培训的变电站三维仿真系统,简要说明其软硬件环境,介绍二维、三维仿真教学培训功能。通过变电站母线接地故障仿真、变电站巡视仿真、操作票仿真3个应用案例来介绍该系统的操作流程、三维特性和应用优势,旨在锻炼参与人员的实际操作能力。系统具有良好的兼容性、真实性和可扩展性,实践应用效果较好,可满足当前智能电网环境下电力人才的培养需求。     

云环境下的高校财务信息平台建设

分析了云环境下的高校财务信息化建设,从云环境架构、财务信息平台建设思路、云环境下的财务信息平台建设内容这三个方面展开,以资金结算系统和财务核算系统为例进行分析,将其结合在云平台上构建财务信息平台,实现信息共享,提高财务耦合,充分发挥资源作用.     

基于C/S和B/S混合结构的物联网智能远程环境监控系统研究

在物联网智能家畜养殖环境监控系统中,服务端与各监控节点以及监控节点与各监控终端的通信方式是基于连接的TCP通信。系统作为数字化养殖与全产业链溯源平台的一个子系统,需要与其进行整合,而平台系统采用B/S结构为用户提供信息服务。为解决该问题,研究并设计了一个C/S与B/S混合体系结构模型,并将该模型应用于系统设计中。同时,为了使服务端能与平台系统的Web服务端有机结合,采用向Web服务器内嵌子线程的方式设计系统服务端。系统测试及试运行结果表明,该解决方案能够满足系统设计需求,性能稳定、响应及时,有效保障了系统的信息一致性。     

基于物联网技术的校园智能照明控制系统研究

针对学校传统照明控制系统的不足和电能浪费现象,设计并实现一套基于物联网技术的智能照明控制系统。该系统以红外热释电式传感器、光敏电阻为感知层,实现对室内人数情况和外界环境光强度等信息进行监测,获得的有效监测信息将送至STC12C5410AD单片机构成的下位机控制电路,实现室内照明灯的自动分组控制;同时由蓝牙模块构成的网络层把室内情况传送到作为应用层的PC上位机软件平台,实现远程监控。系统测试及初步应用表明:该系统使用灵活、管理方便、性价比高,能有效节约电能,具有较大应用价值和市场前景。     

关于智能变电站监控系统的研究

监控系统是智能变电站中的重要组成部分,关系到变电站的安全可靠运行。然而监控系统往往因电磁干扰影响了系统的稳定性,给变电站运行带来潜在安全隐患。文章主要针对智能变电站的功能特点、系统结构、安全分区、设备配置及发展趋势进行分析。     

基于云服务的科普资源平台研究与设计

针对当前科普资源平台存在的问题,从全新的角度提出科普平台构建方式。通过云计算技术的介入,使用新浪（SAE）云服务,采用瘦客户端模式,完成支持PC客户端和移动智能客户端的科普资源云平台架构模式设计,以及科普资源平台关键开发技术研究。对平台功能进行了详细的设计,为将来云计算技术大规模应用于科普资源平台建设提供了参考。     

基于Wi-Fi的移动视频监控平台

基于解决目前监控系统中监控平台无法移动和数据种类过少等问题,采用以STC89C52为控制芯片,以S3C6410作为核心处理器,使用Linux操作系统,搭载USB高清摄像头、Wi-Fi无线传输模块以及移动监控平台,设计出一款可以对现场的环境和视频信息进行采集,并将视频信息与环境信息同时显示在监控软件上的可移动监控平台。     

基于RFID和WiFi的分布式校园智能考勤系统

为解决高校日常教学管理中传统教师点名考勤方式的低效,采用RFID和WiFi设计实现了基于普通IC卡并能兼容校园卡的课堂智能考勤系统.系统以windows7为开发平台,采用B/S和C/S架构,以MyEclipse以及Keil uVision4为主要开发工具,实现了学生的自主签到,数据的智能感知和存储,考勤数据的分权管理,考勤表格的下载和打印.经测试,系统运行稳定,便捷高效.     

电气工程虚拟仿真实验教学平台

电气工程专业实验教学面临强电威胁,加之电网不允许破环性实验,因而虚拟仿真实验成为发展方向。本文主要介绍了广西大学虚拟实验室建设平台,包括电力云调度仿真教学平台、电力系统动态模拟与虚拟仿真一体化仿真教学平台、变电站运行虚拟仿真和虚拟电工/电子技术系统仿真教学平台。     

基于WebSocket协议的智能温室测控系统设计与实现

针对智能温室发展现状,引入了跨平台、易扩展的思想,将WebSocket通信协议应用到嵌入式设备通信中,结合嵌入式、Zigbee无线传输、传感器采集等技术,设计了一套基于WebSocket协议的智能温室测控系统。一方面能够简化系统开发、克服传统B/S架构不能提供长连接的TCP双向通信和C/S架构开发周期长、无法跨平台等缺点;另一方面,用户可以实时查看温室环境、设备运行状况以及实时控制情况等,并且能够获得实时温室预警等推送。实验结果表明,该系统运行稳定、使用便捷,很好地满足了温室实时测控的功能需求。     

Results on energies for trees with a given diameter having perfect matching

Let Γd2nbe the set of trees with a given diameter d having a perfect matching,where 2n is the number of vertex.For a tree T in Γd2n,let Pd+1be a diameter of T and q = d m,where m is the number of the edges of perfect matching inPd+1.It can be found that the trees with minimal energy in Γd2nfor four cases q = d 2,d 3,d 4,[d2],and two remarks aregiven about the trees with minimal energy in Γd2nfor2d 33q d 5 and [d2] + 1 q2d 33 1.     

Precise asymptotics in the law of the logarithm for random fields in Hilbert space

Consider the positive d-dimensional lattice d (d≥2) with partial ordering ≤, let {XK; K ∈ d } be i.i.d. random vari- ables taking values in a real separable Hilbert space (H, ||·||) with mean zero and covariance operator ∑, and set partial sums SN =∑K≤NXK, K , N ∈ d . Under some moment conditions, we obtain the precise asymptotics of a kind of weighted infinite series for partial sums SN as ε 0 by using the truncation and approximation methods. The results are related to the convergence rates of the law of the logarithm in Hilbert space, and they also extend the results of (Gut and Spǎtaru, 2003).     

On Turán type inequality with doubling weights andA * weights

LetH _n be the set of real algebraic polynomials of degreen, whose zeros all lie in the interval [−1,1]. The well known Turán type inequalities tell us that forf(x)∈H _n , it holds ‖f′‖≥C√n‖f‖. This note deals with the weighted Turán type inequalities with the weights having inner singularities underL ^p norm for 0<p≤∞. Our results essentially extend the result of Wang and Zhou (2002), and the method used in this paper is simpler and more direct than that of Wang and Zhou (2002). The results and methods have their own values in approximation theory and computation.     

On some projectively flat polynomial （α,β）-metrics

In this paper, we consider some polynomial (α,β)-metrics, and discuss the sufficient and necessary conditions for a Finsler metric in the form F=α a1β a2β2/α a4β4/α3 to be projectively flat, where ai (i=1,2,4) are constants with a1≠0, α is a Riemannian metric and β is a 1-form. By analyzing the geodesic coefficients and the divisibility of certain polynomials, we obtain that there are only five projectively flat cases for metrics of this type. This gives a classification for such kind of Finsler metrics.     

Projectively flat Asanov Finsler metric

In this work, we study the Asanov Finsler metric F=α(β2/α2 gβ/α 1)1/2exp{(G/2)arctan[β/(hα) G/2]}, where α=(αijyiyj)1/2 is a Riemannian metric and β=biyj is a 1-form, g∈(-2,2), h=(1-g2/4)1/2, G=g/h. We give the necessary and sufficient condition for Asanov metric to be locally projectively flat, i.e., α is projectively flat and β is parallel with respect to α. Moreover, we proved that the Douglas tensor of Asanov Finsler metric vanishes if and only if β is parallel with respect to α.     

Infrared Absorption Spectra of Serpentine Cat＇s Eye from Sichuan Province of China

Infrared （IR） absorption spectra and X-ray powder diffraction （XRD） patterrns of sexpenfine cat＇s eye from Sichuan Province have been investigated, and infrared absorption bands of the serpentine have been assigned in this paper. The results indicate that the bands near 3 600 - 3 700 cm^-1 belong to the stretching absorption band VOH, the bands in 948 - 1 100 cm^-1 axe assigned to the stretching vibraling band Usvo, and the bands at 600 570 and 440 cm^-1 respectively belong to the bending vibration band VOH, δMg-O and δSi-O. The serpentine cat＇ s eye includes two types： chrysotile and antigorite. Chrysotile has a sharp and intensive band at 3 688 cm^-1 and a weak band at 3 643 cm^-1 , while antigorite has only one intensive band in the region. At vibration band VSi-O, chrysotile and antigorite have a similar feature at 1 071 cm^-1, but the band at 980 cm^-1 in anfigorite has been split into two bands in chrysotile - a strong one at 1 027 cm^-1 and a weak one at 949 cm^-1. In addition, antigorite has a characteristic bending vibrating band δMg-O at 570 cm^-1. Based on the analysis of the feature of crystal structure, their IR differences axe well explained.     

Supposer et postuler pour produire des connaissances scientifiques: une évidence ou une conquête théorique? Une étude des points de vue d'étudiants

Résumé De manière générale, l'évidence sensorielle et, plus particulièrement, visuelle constitue pour les étudiants le principal fondement du savoir scientifique: nul besoin de supposer pour connaître, tout est donné ou presque. Du point de vue de l'enseignement des sciences, cette croyance à saveur réaliste est particulièrement critique, notamment parce qu'elle conduit à penser que les concepts, lois et théories scientifiques procèdent d'un monde de matérialités plutôt que d'un monde de modèles et de relations. Au cours d'une recherche effectuée auprès d'un groupe-classe de 35 étudiants durant douze semaines, nous avons pu observer que, pour la majorité des étudiants, la compréhension du caractère construit et consensuel du savoir scientifique était facilitée par le développement d'une métaréflexion sur leurs propres productions de connaissance et les inévitables postulats et suppositions qui les fondent. Nous avons également pu observer qu'il découle de cette activité réflexive un modèle de science qui se distingue des modèles initialement tenus par les étudiants, par le pouvoir créateur et, surtout, le pouvoir de théoriser qu'il comporte: postuler, supposer, jauger collectivement de la plausibilité des résultats plutôt qu'en appeler à une instance occulte, voilà quelques-unes des conquêtes théoriques qu'ils ont effectuées et sur lesquelles nous allons nous attarder.

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Sensorial, and more specifically, visual evidence is generally regarded by students as the basis for scientific knowledge: no need to postulate to understand, all is almost or practically given. From a science-teaching standpoint, this rather realistic approach is critical and leads to the belief that scientific concepts, laws, and theories stem from a world of materiality rather than from a world of models and relationships. During a 12-week study a group of 35 college students, we observed that for the majority of them, the development of metareflection on how they produce knowledge, with the inevitable and inherent postulates and conjecture, facilitated their understanding of the constructed and consensual character of scientific knowledge. We also observed that this reflexive activity facilitated the development of a new approach to science that differed from those models previously used by the students in its creative potential and, more importantly, in the power of its theoretics: to postulate, suppose, and collectively estimate the plausibility of results rather than calling up occult instances. These and other theoretical achievements will be discussed in this paper.

     

Li1xNaxV3O8电极在硫酸锂-水-乙醇体系中的电化学性能

A series of Lil-xNaxV3O8 materials was prepared by solution reaction followed by calcination method and their electrochemical performances in 2 M LieSOa-water-ethanol solution as negative electrodes for aqueous electrolyte lithium ion battery were studied and compared each other. X-ray diffraction analysis revealed that partially substituting sodium for lithium in LiV3Os could increase the interlayer distances of （100） plane. Cyclic voltammetric experiments have demonstrated that the Li^＋ insertion and extraction kinetics of Li0.7Na0.3V3O8 is superior to that of LiV3O8. Charge/discharge results showed that the discharge specific capacity of Li0.7Na0.3V3O8 electrode is higher than that of LiV3O8 electrode.     

Phase diagram estimation of the Al2O3-SiO2-Re2O3 systems

Nine limiting binaries of Al₂O₃-SiO₂-Re₂O₃(Re=Nd, Sm, Gd and La) system are assessed. The binary diagrams or experimental information from Toropov, Mizuno, Aramaki, Bondar, Rolin and Coutures are optimized with the substitutional model of Kaufman and Nesor and the approximate formula of fusion free energy for rare earth element oxides of Wu and Pelton. The extracted Gibbs free energies of pure solid oxides and stoichiometric phases and the solution parameters are used to estimate the corresponding binaries, liquidus surfaces and a series of isothermal sections of four ternaries Al₂O₃-SiO₂-Nd₂O₃, Al₂O₃-SiO₂-Sm₂O₃, Al₂O₃-SiO₂-Gd₂O₃, and Al₂O₃-SiO₂-La₂O₃. In the Al₂O₃-SiO₂-Gd₂O₃ system samples as fired at exact temperature with different compositions were analyzed by X-ray diffractometer and the detected results are fitted with the calculation of isothermal sections. Supported by State Key Lab of High Performance Ceramics and Superfine Micro-structure (9517 and 9708)