995 resultados para Internet fraud - Prevention


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落叶松毛虫是东北林区主要害虫之一,它对松林可以造成毁灭性的破坏,因此,采取及时且必要的综合防治措施,可以带来显著的经济和生态效益。本文依据害虫综合管理的指导思想,采用计算机人工智能程序模型,构建了落叶松毛虫防治咨询专家系统。 落叶松毛虫防治咨询专家系统主要由推理机、知识库、数据库、知识获取机制和用户界面等部分组成。其中知识库和推理机是系统的核心部分。在知识库设计中充分考虑了落叶松毛虫防治的复杂性,结合具体的限定条件,如危害特征、自然环境、地形地貌、害虫的生长阶段等,将知识存储在数据库中形成专家数据库;利用数据库查询语言SQL语句设计了系统的推理机,采用正向推理的方式,增强了知识库的可扩展性和可维护性;知识获取机制面向林业专家,实现知识的获取以及知识库的修改、扩充等任务;数据库用来存放落叶松毛虫的基本信息,用户可以通过数据库来获得落叶松毛虫相应的咨询信息。 落叶松毛虫防治咨询专家系统的目标为:(1)对落叶松毛虫的基本信息、行为特征、生理和生态学特征以及防治方法和施药方法等进行存储和查询。(2)正向推理方式保证专家系统在运行时能方便地选择问题,实现智能推理过程。(3)易用的知识维护。 该系统主要有以下几方面的功能和特点:(1)该系统本着害虫综合管理的指导思想,以落叶松毛虫的种群动态为理论基础,充分考虑不同林地环境条件下的自然控制因素,根据环境、气候和害虫本身的条件推出更加合理的结论,尽量采用生物防治,必要时采用化学防治;(2)系统可向用户提供多种可行的防治方案,经营者可以根据当时当地的实际情况作出决定;(3)系统使用方便;(4)系统具有显示、打印、通过Internet浏览获取信息、显示推理解释等功能。 另外,本文对落叶松毛虫专家系统又进行了有效的评估,评估对象分为三个组别:领域专家、森保人员以及学生。三组人员分别针对系统实用性、友好性、系统提问的简洁程度以及可学习性给出等级分数。通过评估结果,最终认定该系统是可以信赖的。 本系统以落叶松毛虫防治领域专家的经验和知识为基础,有效地将计算机技术和森保专家的知识结合在一起,集落叶松毛虫信息存储浏览、查询、专家系统于一体,对于缓解森林保护专家和人员的不足,提高落叶松毛虫虫害的防治能力,加快科技成果的转化具有重要的意义。

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Polyaniline emeraldine base/epoxy resin (EB/ER) coating was investigated for corrosion protection of mild steel coupled with copper in 3.5% NaCl solution. EB/ER coating with 5-10 wt% EB had long-term corrosion resistance on both uncoupled steel and copper due to the passivation effect of EB on the metal surfaces. During the 150 immersion days, the impedance at 0.1 Hz for the coating increased in the first 1-40 days and subsequently remained constant above 10(9) Omega cm(2), whereas that for pure ER coating fell below 10(6) Omega cm(2) after only 30 or 40 days. Immersion tests on coated steel-copper galvanic couple showed that EB/ER coating offered 100 times more protection than ER coating against steel dissolution and coating delamination on copper, which was mainly attributed to the passive metal oxide films formed by EB blocking both the anodic and cathodic reactions. Salt spray tests showed that 100 mu m EB/ER coating protected steel-copper couple for at least 2000 h.

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Conductive polyaniline was found to have special marine antifouling property. The coating from conducting polyaniline and epoxy resin(or polyurethane) can last 6-9 months in Southern China sea, i.e., less than 10% of the coating surface was fouled during this period. The conducting polyaniline has special synergetic antifouling effect on other antifouling agents like cuprous oxide or 4, 4'-dichlorodiphenyltrichloroethane. The conductivity of the polyaniline was found to be extremely important for its antifouling effect. Moreover, employing aliphatic polyamine as solvent of emeraldine base and curing agent of epoxy resin, a new technique to process corrosion prevention coating containing emeraldine base was developed, therefrom the emeraldine base and epoxy resin was in molecular level blending. This technique was solvent free and extremely effective, i.e., only 1wt% of emeraldine base in the coating can have good corrosion prevention property.