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0IntroductionSubmerged arc welding(SAW)is a welding processwhere the arc burns under flux[1].Automatic SAW hasbeen widely put into practice in the fields of ship-building,energy industry and mechanical engineering for its high ef-ficiency,good quality,flexibility of adjustment and fairlynice working condition.In a word,SAW can carry outwelding of high quality with high current at high speed.High heat input is usually applied for more depositedmetal when SAWis used to weld thick plate.In … 相似文献
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拒绝服务攻击已经成为威胁互联网安全的重要攻击手段,本文介绍了分布式拒绝服务(Distributed Denial of Service,DDo S)攻击的概念,分析了DDo S攻击的原理;最后介绍了多种IP溯源技术的优缺点。 相似文献
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Image retargeting technologies require important information preservation and less edge distortion during increasing/decreasing image size. The seam carving based algorithms, as the classic retargeting model, receive widespread attention in recent years. However, because of the discrete least energy seam searching strategy, the retargeting information can not be passed generation by generation, which causes retargeting distortions to prevail. To solve this problem, the Just Noticeable Distortion (JND) algorithm is proposed to detect the potential distribution of distortion information. Through the proposed energy weight Ew, the JND information can be passed to the following retargeting iteration for distortion reduction. According to the best knowledge, it is the first time to propose the seam carving algorithm in continuous way by the JND algorithm and energy weight, are the promising results also demonstrated compared with several new approaches at public database ‘Retarget Me’, qualitatively and quantitatively. 相似文献
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2009第四届亚洲国际标签印刷展览会(Labelexpo Asia)即将于今年12月1—4日在上海新国际博览中心隆重召开。本届展会是在2007年成功举办的基础上,举办的第四届展览会。尽管离展会正式开幕还有一段时间,近2万平米的毛展出面积已经基本销售一空,其中21%的参展商是首次参展,这再次证明了亚洲国际标签EP@U展览会是本地区标签印刷行业内展出面积最大、组织信誉最良好的专业展览会。 相似文献
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建立了同时测定化妆品中23种香料致敏成分的高效液相色谱法。样品经乙腈超声提取15min,以8000r/min离心5min,取上清液过滤后测定。采用Aglient ZORBAX SB-C18(4.6×250 mm,5μm)色谱柱, 以乙腈-水为流动相梯度洗脱,采用二极管阵列检测器多波长检测(200、210、240、290nm)。23种致敏成分的定量限分别为1.25、2.5、5.0、10.0μg/kg,线性范围内相关系数均大于0.99。在1倍定量限、2倍定量限,10倍定量限浓度的添加水平下平均回收率为80%-110%,相对标准偏差为0.5%-9.3%。该方法简单、准确、快速,适用于化妆品中23种致敏成分的测定。 相似文献