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Polyoxometalates (POMs) form a large class ofmetal oxide cluster type compounds. Their wealthytopology, physical and chemical properties have at tracted increasing interests. In this paper, based onour group’s research, we review the latest progress inthe synthetic chemistry and catalysis of POMs and in troduce some POMs with novel structure and theirderivatives that emerged in 2002—2004. Most of thecited references come from those published in 2003.Due to POMs’superio… 相似文献
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Masahiro Shoji *Department of Mechanical Engineering School of Engineering the University of Tokyo Hongo Bunkyo ku Tokyo Japan 《清华大学学报》2002,7(2)
IntroductionThe behavior of bubbles,especially theirformation,interaction and coalescence,are of keyimportance in such fields as gas- liquid contact,gas- liquid separation,bubble absorption,bubblecolumns,fermentation,cavitations,etc. Theinduced fluid moti… 相似文献
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CHEN Xiaohong * LIU Mai * YASUHIKO Takahara ** *College of Business Management Central South University of Technology Changsha Hunan P.R. China ** Department of Management Systems Engineering China Institute of Technology Ch 《系统科学与系统工程学报(英文版)》1998,(1)
ComparativeAnalysisandFuzzySelectionofInformationSystemDevelopmentApproach⒇CHENXiaohong*LIUMai*YASUHIKOTakahara***ColegeofBus... 相似文献
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WANG Xiang BAO WanSu* & FU XiangQun Institute Electronic Technology People’s Liberation Army Information Engineering University Zhengzhou China 《科学通报(英文版)》2011,56(6):484-489
To search for a target n-product Boolean vector of fixed weight d, we propose an important method involving the notion of a fixed-weight "vector label" accompanied with a vector label restoration algorithm. Based on these, we present a new quantum algorithm designed to search for a fixed-weight target whose computation complexity, specifically O ((Cdn+1)1/2) , is better than that for a classical algorithm. Finally, we use the procedure to search for the NTRU private key as an example to verify the efficiency of the new algorithm in searching for fixed-weight target solutions. 相似文献
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在六甲基二硅胺烷的催化作用下,以芳香醛与2,2-二甲基-1,3-二烷-4,6-二酮为原料,经缩合反应合成了10种芳基亚甲基麦氏酸化合物.考察了反应温度、反应时间、催化剂用量等因素对反应的影响.确定了最佳反应条件为:取0.1 mol 2,2-二甲基-1,3-二烷-4,6-二酮, n(2,2-二甲基-1,3-二烷-4,6-二酮)∶n(芳香醛)=1.01.1,∶催化剂用量为0.1 mol,反应温度为室温,反应时间为1.0 h,在上述反应条件下,产品收率可达86.8%~92.1%. 相似文献
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目的研究三色马先蒿、决明子和连翘的抗运动性疲劳作用.方法以小鼠游泳训练为模型,观察上述三味中药对4周递增大强度负荷运动小鼠体重、食欲等疲劳相关症状和体征及力竭游泳时间的影响.结果实验第四周末单纯运动组小鼠活动减少,毛发枯萎,无光泽,有的小鼠出现大片脱毛现象,食欲减少,体重降低;而运动+决明子组、运动+连翘组和运动+三色马先蒿组上述疲劳相关的症状与体症明显减轻,食欲增加,体重持续增长.单纯运动组小鼠力竭游泳时间明显低其余三组,P <0.01.运动+三色马先蒿组小鼠力竭游泳时间明显高于运动+决明子组和运动+连翘组小鼠,P <0.05;与阳性对照组(人参提取物)比较,差异无显著性,P >0.05.结论三色马先蒿、决明子和连翘均具有一定的抗运动性疲劳作用,但以三色马先蒿的效果最好 相似文献
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定量评价西藏牧区能值生态足迹,明确其优势与不足,可为西藏研究与“一带一路”国家生态安全屏障构建提供有益借鉴。通过运用改进的能值生态足迹法与GM(1,1)模型对西藏牧区能值生态足迹动态演进及发展趋势进行测算、分析与模拟。结果发现:(1)2007~2016年EEF变幅在1.757 603~3.353 526 hm2之间,呈现出持续上升趋势。EEC变幅在2.576 530~2.249 599 hm2之间,表现为平缓下降轨迹。EEP变幅在0.818 927~-1.103 927 hm2之间,年均值为-0.152 384 hm2,平均递减率为1.50%。说明西藏牧区生态系统出现能值赤字,处于弱不可持续发展状态;(2)可再生资源对EEC贡献最大的是太阳能,其次是风能,但人均能值生态承载力不高,反映出西藏牧区禀赋优势明显的清洁能源开发、利用程度欠充分;(3)2017~2021年EEP预测值年均递减率为0.99%,能值赤字较前明显减缓,生态系统弱不可持续发展状态有所改观,但牧区生态安全面临潜在威胁。在此基础上,提出了“一带一路”战略下西藏牧区优化国家生态安全屏障的建议。 相似文献
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