基于粗糙集和证据推理的网络入侵检测模型

证据推理依赖于专家知识提供证据,要求各证据体相互独立,因此难以应用于实际。针对上述问题,提出基于粗糙集理论的证据获取和基本概率赋值客观确定方法,利用粗糙集中的属性约简算法剔除冗余属性,形成最简属性集,以提高证据合成效率,缩短证据合成时间,减少证据合成的冲突现象。在此基础上建立一个基于粗糙集和证据推理的网络入侵检测模型,通过算例验证该模型检测精度较高、误检率较低。     

考虑感应电动机负荷电磁暂态特性的系统短路电流计算方法

首先分析了BPA程序所采用的二阶静态负荷模型对系统短路电流计算之前的潮流计算中迭代算法所涉及的问题,然后深入研究分析了感应电动机负荷特性及其对系统短路电流计算的影响。建立了在现有以恒定阻抗作为系统各节点负荷的短路电流计算方法中考虑适应感应电动机电磁暂态过程的系统短路电流的修正计算方法,提出了相应的系统短路电流计算程序编制的具体实施思路。初步验证了本文所提出的方法的可行性。     

基于Oracle的通用数据格式的电力系统模拟程序设计

在Oracle数据库上建立了一个基于VB.net的应用程序,来解决电力系统仿真程序的数据转换问题。电力系统的常见模拟模式是建立在Oracle数据库中,作为平台的一站式数据保存。用VB开发程序将数据转移到数据库中,并将数据转换为不同的格式。测试结果表明转换可以方便的操作,并且提高了工作效率和精度。     

BPA向PSS/E的数据转换及暂态稳定比较研究

BPA和PSS/E均为机电暂态仿真软件,两者潮流数据和暂态模型具有较好的相似性,在对BPA和PSS/E两种仿真软件的暂稳态数学模型分析和比较的基础上,提出了BPA向PSS/E数据转换的详细方法,并通过某交直流系统进行仿真测试,对潮流计算结果和稳定计算结果进行了对比分析,仿真结果表明两者潮流基本一致,暂态仿真结果相似,暂稳态过程基本吻合,表明BPA数据可以准确的转换为PSS/E数据,实现数据共享.     

马齿苋茎部提取物对双酚A的降解效应研究

大量研究证明:双酚A(BPA)具有环境雌激素作用,极低剂量摄取就能破坏人体的内分泌系统,已成为一种全球性污染物。文章以2mL蒸馏水比1g马齿苋茎部的比例浸提其活性物质,用于双酚A的生物降解。研究了样品中双酚A的初始浓度、光照、透析等因素对马齿苋茎部提取物降解双酚A的影响。实验结果显示:在连续光照及透析条件下,20mLBPA中加入1mL茎汁降解时获得的效果较好,浓度为5mg/L、10mg/L的双酚A在24h内可完全降解,40mg/L的双酚A降解率达到67%。     

Application of Slurry Type Photocatalytic Oxidation‐Submerged Hollow Fiber Microfiltration Hybrid System for the Degradation of Bisphenol A (BPA)

Abstract

A pilot scale, slurry type photocatalytic reactor, followed by submerged hollow fiber microfiltration (MF) membrane hybrid system was evaluated for simultaneous and complete destruction of toxic organic chemical bisphenol A (BPA) and separation of photocatalyst TiO₂; in order to obtain a reusable quality water. With simple modification to the treatment operation, the effect of photocatalytic reaction at modest variations in temperature was examined. Adsorption pretreatment was carried out prior to photocatalysis (UV/TiO₂). BPA adsorption ability on TiO₂ was very less (about 15%) at 25°C. However, adsorption pretreatment followed by photocatalytic oxidation (UV/TiO₂) at an elevated nearly constant temperature (about 70°C) helped in increasing the BPA degradation efficiency. The effect of ozone introduction into the treatment stream was also analyzed. Applying ozone along with UV/TiO₂, brought about a synergistic effect on BPA degradation. Within 3 h, entire 10 ppm of BPA and the by‐product organic compounds were completely removed. TiO₂ particle separation performance using hollow fiber membrane was enhanced by adopting a two‐stage coagulation/sedimentation pretreatment. With initial turbidity of 4000 NTU, the turbidity of the final permeate water was well below 0.1 NTU. Almost complete removal of particles was achieved. Some of the main advantages of this hybrid treatment system include, large‐scale treatment, complete and efficient BPA and its organic intermediates degradation, TiO₂ easily separated after treatment and capable for reuse as it is free from chemical coagulant contaminants, reusable quality water is obtained, and the system has the potential for continuous operation with simple process modifications.     

双酚A装置基于风险检验技术的应用

对某企业双酚A装置进行风险评估,发现10%的设备和管道承担了装置90%的风险。随着时间的推移,装置风险有了较大增高,因此需要定期检验来降低装置风险。根据装置风险评估的结果制定检验方案,实践证明基于风险的检验更具针对性,也降低了装置的风险,为企业节约了成本。     

Preparation and characterization of TiO2/Ti film electrodes by anodization at low voltage for photoelectrocatalytic application

Multiporous TiO₂/Ti film electrodes were prepared by different anodic oxidation processes at low voltage, in which the micro-structured TiO₂ thick films were prepared in H₂SO₄–H₂O₂–H₃PO₄–HF solution for 2 h and the nano-structured TiO₂ thin films were prepared in H₃PO₄–HF solution for 30 min with post-calcination. Both types of TiO₂/Ti films were characterized by scanning electron microscopy and X-ray diffraction analysis. The photocatalytic (PC) and photoelectrocatalytic (PEC) reactivity of the TiO₂/Ti electrodes were evaluated in terms of bisphenol A (BPA) degradation in aqueous solution. The experimental results demonstrated that the nano-structured TiO₂/Ti thin-film electrodes had higher reactivity in the BPA degradation reaction. The PEC degradation of BPA was further studied using different cathodes, either a reticulated vitreous carbon (RVC) electrode or a platinum (Pt) electrode. The experimental results confirmed that the efficiency of BPA degradation could be significantly enhanced in the TiO₂/Ti–RVC reaction system due to the generation of H₂O₂ on the RVC cathode. It is believed that such a H₂O₂-assisted TiO₂ PEC oxidation process may have good potential for water and wastewater treatment.     

广东电网运行策划管理系统研究与实现

传统的检修计划编排工作主要依靠电网运行方式人员对电网历史及当前运行方式的熟悉程度和工作经验,缺乏科学和可量化的数据进行参考。由于没有可靠的辅助手段,使得因检修可能造成的电网潜在安全风险无法预先识别和评估。广东电力调度控制中心针对该现状,将检修计划编排与电网安全风险管理体系结合,立项研发广东电网运行策划管理系统,目前已在广东中调上线运行。文章介绍该系统在系统架构、设计等方面的技术实现方式。