排序方式: 共有166条查询结果,搜索用时 171 毫秒
161.
DU Ying-da XING Ming YANG Zhi-yong LIU Yan-fei CHEN Xia College of Life Science Jilin University Changchun P.R.China 《高等学校化学研究》2011,(4):641-645
Multiplex environmental factors are generally expected to have significant effects on genetic diversity of plant populations.In this study,randomly amplified polymorphic DNA(RAPD) technique was used to reveal the genetic diversity in the same species of four populations collected from Niupidujuan(Rhododendron chrysanthum) at different altitudes,an endangered species,endemic to Northeast China.Initially,twenty informative and reproducible primers were chosen for final RAPD analysis.A total of 152 clear bands... 相似文献
162.
先用硫脲修饰的量子点为核,再用聚丙烯酸包覆,并用聚乙烯吡咯烷酮K-30为稳定剂,合成粒径分布均匀、性能稳定的核壳结构水溶性量子点荧光体。采用荧光发射光谱、红外光谱和透射电镜对样品进行表征并探索核量子点在聚丙烯酸聚合物溶液中含量对量子点荧光体的影响。结果表明:聚丙烯酸修饰后量子点粒径分布更均匀;荧光发射主峰由548nm蓝移到448nm。红外光谱图中2 092.8和1 384.3cm-1分别归属于羧基的CO和C—O伸缩振动,1 644.5cm-1归属为酰胺键的CO伸缩振动,核量子点在聚丙烯酸聚合物溶液中最佳含量为2.67mg.mL-1。该量子点制备方法简单易行,具有较好的稳定性及高荧光量子效率,为进一步应用于生物标记奠定基础。 相似文献
163.
Cu/Co/Mn基氧载体释氧动力学及机理研究 总被引:2,自引:1,他引:1
以溶胶凝胶法制备了CuO/CuAl2O4、Co3O4/CoAl2O4以及Mn2O3/Al2O3氧载体,在流化床反应器中CO2气氛下研究了不同温度下氧载体释氧特性,并通过分析得到各氧载体的释氧动力学机理函数、活化能及指前因子等重要参数。释氧过程中,氧载体CuO/CuAl2O4中CuO、CuAl2O4均为活性相,释氧后转化为Cu2O及CuAlO2,而Co3O4/CoAl2O4及Mn2O3/Al2O3中CoAl2O4和Al2O3均为惰性相,仅有Co3O4和Mn2O3参与释氧并分别转化为CoO和Mn3O4。三种氧载体的释氧过程均可由成核-核生长机理描述,释氧初期氧载体经化学反应形成新的活性核心,随后活性核心聚集形成还原态的氧载体团簇。各氧载体释氧的机理函数G(x)有不同的表达式,CuO/CuAl2O4、Co3O4/CoAl2O4、Mn2O3/Al2O3释氧的活化能E分别为226.37、130.06和65.90 kJ/mol,相对应的指前因子A分别为2.99×106、4.96×103和27.37 s-1。 相似文献
164.
Yan-fei Wang Qing-hua Ma 《应用数学学报(英文版)》2006,22(3):429-436
The adaptive regularization method is first proposed by Ryzhikov et al. in [6] for the deconvolution in elimination of multiples which appear frequently in geoscience and remote sensing. They have done experiments to show that this method is very effective. This method is better than the Tikhonov regularization in the sense that it is adaptive, i.e., it automatically eliminates the small eigenvalues of the operator when the operator is near singular. In this paper, we give theoretical analysis about the adaptive regularization. We introduce an a priori strategy and an a posteriori strategy for choosing the regularization parameter, and prove regularities of the adaptive regularization for both strategies. For the former, we show that the order of the convergence rate can approach O(||n||^4v/4v+1) for some 0 〈 v 〈 1, while for the latter, the order of the convergence rate can be at most O(||n||^2v/2v+1) for some 0 〈 v 〈 1. 相似文献
165.
研究了三嗪系列阻燃剂三烯丙基异三聚氰酸酯(TAIC)、二烯丙基溴丙基异三聚氰酸酯(DABC)、二(2,3-二溴丙基)烯丙基异三聚氰酸酯(DBAC)、三(2,3-二溴丙基)异三聚氰酸酯(TBC)与丙烯酸系树脂单体的聚合情况.证明不饱和的三嗪阻燃剂确实是丙烯酸系树脂的活性阻燃剂.并对三嗪系列阻燃剂TAIC、DABC、DBAC、TBC对丙烯酸系树脂的阻燃性能进行了进一步验证. 相似文献
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