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安全滤网阵列网孔激光-电解组合加工 被引量:2
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作者 葛声宏 申继文 曾永彬 《光学精密工程》 EI CAS CSCD 北大核心 2023年第12期1774-1784,共11页
安全滤网阵列网孔的高效、高品质和高适应性加工至今仍面临重大技术挑战。基于此,提出采用激光-电解组合加工技术制备安全滤网阵列网孔结构。介绍了激光-电解组合加工技术的试验加工系统,探究了工艺参数对微孔形貌质量和加工精度的影响... 安全滤网阵列网孔的高效、高品质和高适应性加工至今仍面临重大技术挑战。基于此,提出采用激光-电解组合加工技术制备安全滤网阵列网孔结构。介绍了激光-电解组合加工技术的试验加工系统,探究了工艺参数对微孔形貌质量和加工精度的影响规律,并开展了安全滤网阵列网孔的制备。试验结果表明:激光加工路径显著影响微孔出口的形貌,采用同心圆轨迹(外径270μm,内径230μm,线间距2.5μm)能够显著改善微孔出口的圆度;激光功率越大、切割速度越小,微孔直径及其热影响区均越来越大;NaNO3-乙二醇溶液作为电解抛光液能够在加工表面形成扩散层发生电解抛光,将激光加工产生的喷溅物和毛刺等缺陷去除;基于优化工艺参数,加工出253个直径0.31 mm的阵列网孔结构,出入口直径方差仅为2.02和1.71,展示出较高的尺寸一致性。激光-电解组合加工技术在薄壁件上高效、高品质制备阵列网孔结构方面具有很强工艺能力和发展潜力。 展开更多
关键词 组合加工 激光加工 电解加工 安全滤网 阵列
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三门核电一期工程安全壳再循环滤网的改进
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作者 蔡龙霆 《中国高新技术企业》 2015年第28期33-35,共3页
在发生丧失冷却剂事故后,安注箱、堆芯补水箱、非能动余热导出热交换器将相继投用,最终机组将进入安全壳长期再循环。文章阐述了安全壳再循环滤网的历次改进,分析了安全壳再循环滤网的设计概况,列举了可能的碎片源,提出了首次装料前的... 在发生丧失冷却剂事故后,安注箱、堆芯补水箱、非能动余热导出热交换器将相继投用,最终机组将进入安全壳长期再循环。文章阐述了安全壳再循环滤网的历次改进,分析了安全壳再循环滤网的设计概况,列举了可能的碎片源,提出了首次装料前的踏勘注意事项,与EPR机组的ECCS滤网进行了比较,并陈述了总体结论。 展开更多
关键词 非能动 安全壳再循环 冷却剂事故 核电站 发电机组
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Improving the precision of the keyword-matching pornographic text filtering method using a hybrid model 被引量:3
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作者 苏贵洋 李建华 +1 位作者 马颖华 李生红 《Journal of Zhejiang University Science》 EI CSCD 2004年第9期1106-1113,共8页
With the flooding of pornographic information on the Internet, how to keep people away from that offensive information is becoming one of the most important research areas in network information security. Some applica... With the flooding of pornographic information on the Internet, how to keep people away from that offensive information is becoming one of the most important research areas in network information security. Some applications which can block or filter such information are used. Approaches in those systems can be roughly classified into two kinds: metadata based and content based. With the development of distributed technologies, content based filtering technologies will play a more and more important role in filtering systems. Keyword matching is a content based method used widely in harmful text filtering. Experiments to evaluate the recall and precision of the method showed that the precision of the method is not satisfactory, though the recall of the method is rather high. According to the results, a new pornographic text filtering model based on reconfirming is put forward. Experiments showed that the model is practical, has less loss of recall than the single keyword matching method, and has higher precision. 展开更多
关键词 Pornographic text filtering Content based filtering Information filtering Network content security
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SAFE:a Scalable Filter-Based Packet Filtering Scheme 被引量:1
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作者 LU Ning HU Wenhao 《China Communications》 SCIE CSCD 2016年第2期163-177,共15页
Recently, attacks have become Denial-of-Service (DOS) the mainstream threat to the internet service availability. The filter-based packet filtering is a key technology to defend against such attacks. Relying on the ... Recently, attacks have become Denial-of-Service (DOS) the mainstream threat to the internet service availability. The filter-based packet filtering is a key technology to defend against such attacks. Relying on the filtering location, the proposed schemes can be grouped into Victim-end Filtering and Source-end Filtering. The first scheme uses a single filtering router to block the attack flows near the victim, but does not take the factor that the filters are scarce resource into account, which causes the huge loss of legitimate flows; considering each router could contribute a few filters, the other extreme scheme pushes the filtering location back into each attack source so as to obtain ample filters, but this may incur the severe network transmission delay due to the abused filtering routers. Therefore, in this paper, we propose a scalable filter-based packet filtering scheme to balance the number of filtering routers and the available filters. Through emulating DoS scenarios based on the synthetic and real-world Intemet topologies and further implementing the various filter-based packet filtering schemes on them, the results show that our scheme just uses fewer filtering routers to cut off all attack flows while minimizing the loss of legitimate flows. 展开更多
关键词 internet security DoS attacks filtering scheme
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