排序方式: 共有14条查询结果,搜索用时 31 毫秒
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采用AMI方法研究了10种新型的磺酰脲类除草剂的电子结构,并以原子的Mulliken净电荷和除草剂在不同浓度(100,10mg/L)下对油菜、稗草两种作物的根、茎部位的抑制率为训练样本集。构造并训练得到具有活性预测能力的BP神经网络.结果表明,该BP网络不仅能对训练样本很好拟合。亦能对未知化合物的活性作出很好的预测. 相似文献
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本文给出了多维OU型Markov过程常返性判别的一个充分条件,并由此讨论了几类多维OU型Markov过程的常返性,同时以一个实例说明了此条件不是多维OU型Markov过程常返的必要条件。 相似文献
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在电离层释放H2O, CO2, H2和SF6等中性气体能导致释放区域电子损耗, 形成明显的人工电离层洞, 是电离层人工变态的重要而有效的手段之一. 本文在改进电离层化学物质释放三维动力学模型的基础上, 对不同释放量级的H2O 和SF6在不同释放高度下产生的电离层洞形态结构及其时空演化规律进行了系统对比研究, 探讨了释放高度对化学物质释放电离层扰动效果、电离层洞形态及其动力学特性等的影响, 并对其成因进行了分析.
关键词:
化学物质释放
电离层扰动
人工电离层洞
三维动力学模型 相似文献
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A new material of zirconium pillared montmorillonite added with lanthanum (denoted as La/Zr/MMT) was prepared for acetone oxidation. Surface properties of the catalysts were investigated by means of XRD, TEM, TG-DTA and BET methods. The XRD result indicated that the interlayer space of the montmorillonite was enlarged from 1.57 to 4.85 um after the treatment with zirconium pillaring and the addition of lanthanum. N2 adsorption-desorption result showed that by the process of zirconium pillaring, the specific surface area of the sample was increased to 128.0 m^2/g, which was two times almost as large as pure montmorillonite. Simultaneously, the thermal stability was also enhanced. The activity of the new material on the total oxidation of acetone was investigated, and the results indicated that the catalytic activity of the montmorillonite was greatly improved. Over the sample of La/Zr/MMT, the T98 of acetone was obtained at 350 ℃, while it needs 400 ℃ over the pure montmorillonite. After 0.1% Pd was supported on the sample of La/Zr/MMT, the T98 decreased from 350 to 280 ℃, indicating the montmorillonite is a promising material for the control of some types of the volatile organic compounds such as acetone. 相似文献
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多普勒效应对紫外吸收温差谱的影响 总被引:2,自引:0,他引:2
探讨了紫外吸收温差谱的形成,谱线加宽可能是其成因之一,不同的物质在不同的温度范围内其主导因素可能各异。分析了温度对多种谱线加宽的影响,并对多普勒效应致温差谱函数进行了理论推导。对于温差谱具有峰位不变和负峰等特征的一类物质,比如C60和黄体酮等,得出的结果可对其给出很好解释,多普勒效应可能是这类物质紫外吸收温差谱形成的主要因素。 相似文献
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