计及相量测量单元信息不可观性的强迫功率振荡扰动源定位

强迫功率振荡的扰动源定位是低频振荡诊断与分析中的重要问题。目前,利用相量测量单元(PMU)的数据进行扰动源位置识别已引起了一定的关注,但相关研究成果大多未考虑PMU尚无法完整配置的现状,因而难以在实际电力系统中推广应用。为此,提出了一种计及PMU信息不可观性的强迫功率扰动源定位方法,并从扰动源定位的角度出发,提出了PMU分区配置的基本要求。仿真结果表明,该方法可在PMU信息不可观的情况下准确识别扰动源位置。     

The 2013 reforms of the Flemish renewable electricity support: Missed opportunities

The Flemish renewable electricity support system has struggled to address a number of problematic issues in the past. These included excessive profit margins and general malfunctioning of the green certificate market, as well as a lack of qualification of various existing renewable energy technologies. The Flemish government responded to these issues by introducing major reforms in 2013, including “banding” to differentiate the support for various technologies. However, reliable methods for differentiating renewable electricity technologies and calculating support levels have not been sufficiently developed. The main objective of the 2013 reforms was to reduce support costs, but application of German feed-in tariffs on 18 reference technologies has shown that most projects in Flanders continue to receive high levels of support. The 2013 reforms did not succeed in addressing malfunctioning of the green certificate market. On the contrary, the confidence of investors in renewable electricity plants has decreased as the terms of support can be altered retroactively by adjusting remuneration levels and through political interventions. Future adaptations are likely to be made which will further decrease the overall stability and effectiveness of the system.     

A new method for evaluating sulfur dioxide tolerance of certain trees

The paper proposes a new method for evaluating the tolerance of trees to SO₂ pollution stress, and grouping plants as indicators and controllers by tolerance index values. The index is calculated by a new arithmetic formula. The developed model is useful in identifying tolerant and susceptible plants to SO₂.     

观赏果树在漳州城市园林绿化中的应用

阐述漳州观赏果树的选择原则,介绍漳州观赏果树的主要种类,总结分析了观赏果树在漳州城市园林绿化中的具体应用,并针对观赏果树在漳州城市园林绿化应用中存在的问题,提出解决对策。     

多关系数据挖掘研究综述

多关系数据挖掘是近年来快速发展的重要的数据挖掘领域之一。传统的数据挖掘方法只能完成单一关系中的模式发现,多关系数据挖掘能够从复杂结构化数据中发现涉及多个关系的复杂模式。该文综述了多关系数据挖掘的研究状况。首先分析了多关系数据挖掘领域发生的原因和背景,其次总结了多关系数据挖掘研究的一般方法,然后介绍、分析了最具代表性的多关系数据挖掘算法。最后,总结了多关系数据挖掘将来发展需重点解决的问题和面临的挑战。     

数据挖掘及实现技术研究

数据挖掘是近年来随着数据库技术的成熟和计算机存储技术的新发展而出现的一门新兴学科。本文讨论了数据挖掘的有关概念、它在社会中的重要作用以及现阶段数据挖掘的主要功能及实现技术。重点分析与研究了数据挖掘中的关联规则、分类和聚类等核心功能及实现技术。     

废弃露天矿山地质环境治理方法研究:以海南某废弃露天矿山为例

保护生态环境,秉持绿水青山就是金山银山的理念,本文通过采用台阶式降坡卸荷的方式治理海南某废弃露天矿山,并设置防护网、安全警示牌等防护措施,以消除安全隐患,利用矿山的特点,植树种草,设置鱼塘,美化环境,达到山水林田湖草为一体的综合治理效果。     

A simple method to derive minimal cut sets for a non-coherent fault tree

Minimal cut sets (or prime implicants: minimal combinations of basic event conditions leading to system failure) are important information for reliability/safety analysis and design. To obtain minimal cut sets for general non-coherent fault trees, including negative basic events or multi-valued basic events, a special procedure such as the consensus rule must be applied to the results obtained by logical operations for coherent fault trees, which will require more steps and time. This paper proposes a simple method for a non-coherent fault tree, whose top event is represented as an AND combination of monotonic sub-trees. A "monotonic" sub-tree means that it does not have both positive and negative representations for each basic event. It is proven that minimal cut sets can be obtained by a conventional method for coherent fault trees. An illustrative example of a simple event tree analysis shows the detail and characteristics of the proposed method.     

Response of Scots pine (Pinus sylvestris L.) to stress induced by different types of pollutants – testing the fluctuating asymmetry

Damage caused to pine forests by industrial pollution is observed even several decades after emissions have stopped down. A simple morphological feature – the leaf fluctuating asymmetry – was used for assessing the condition of Scots pine (Pinus sylvestris) stands growing in a heavily degraded area. In 2011, a study was performed on the developmental instability of needles in four naturally reforested Polish populations of P. sylvestris. Studies were conducted within the protective zone at a zinc smelter, a copper smelter, a cement plant and train tracks. All selected areas manifested a high extent of anthropogenic pollution‐induced environmental degradation until the end of the 90s. Currently, a reduced level of environmental pollution is recorded at these sites. Control group was a natural population of Scots pine from the region of National Park of Wielkopolska. The results confirm the usefulness of fluctuating asymmetry as a highly sensitive indicator of non‐specific stress. Also, it was shown that in areas degraded by human activity, poor condition of Scots pine persists that the stress factor has been eliminated. This tendency occurs particularly to areas contaminated by heavy metals.     

三甘醇（TEG）清洗在PBT聚合装置中的应用

基于三甘醇（TEG）清洗的工作原理,通过对PBT（聚对苯二甲酸丁二醇酯）聚合装置酯化釜进行TEG清洗操作,摸索清洗所需工艺流程改造、清洗操作参数、准备工作,对使用TEG和1,4-丁二醇（BD）为清洗济的清洗效果进行了比较。PBT酯化釜使用TEG进行热清洗后,产品质量得到了提高,清洗过程的产品降等量得到了降低,装置清洗周...