吡氟禾草灵的高效液相色谱法拆分与测定

在流动相为正庚烷-异丙醇-三氟乙酸(99.3:0.5:0.2,体积比),流速为0.6 mL·min-1,检测波长为273 am,柱温为10℃的分析条件下,利用手性色谱柱Nucleosil chiral-2实现了吡氟禾草灵对映体的手性分离,在优化的色谱分离条件下,R-型异构体的峰面积与其对应浓度之间保持线性关系,其对应的线性回归方程为A=(236.30ρ 1.94)×100,其相关系数为0.9991.据此可定量测定R型异构体.     

一种带链规则的变样本容量X图

将一种链规则和变化样本容量的思想一起并入休哈特均值图以加快其发现过程均值小漂移的速度.利用马氏链方法计算了控制图稳态表现下的平均链长.与几种图的比较显示,该图能显著加速发现过程均值小的漂移.     

Theoretical Studies on the N-Phenylpyrrolidine Formation Mechanism Based on the Reaction of Phenylamine with 1,4-Butanediol

The reaction mechanism of phenylamine reacting with 1,4-butanediol to give N- phenylpyrrolidine was investigated with traditional transition state theory. Based on the experimental results, two reaction channels were discussed. The geometries of their reactants, products, intermediates and transition states were optimized. The possible transition State and activation energy were determined by vibrational analysis and IRC verification. And finally, the main reaction channel was given.     

射线成像检测中射线源焦点的影响及修正

本文分析了在工业无损检测中射线源焦点对成像质量的影响，讨论了射线源焦点对成像影响的数学模型，以此为基础，设计了相应的焦点修正算法，并给出了处理结果     

YbxY1-xBa2Cu3O7-y的超导载流特性

本文系统地研究了Yb_xY_1-xBa₂Cu₃O_7-y系统的微结构、超导临界温度以及超导载流特性。发现:随着Yb含量的增大,样品的超导临界温度没有很大变化,但晶粒度逐渐减小,超导临界电流密度系统地下降。作者认为:在这种弱连接颗粒超导体中,细化晶粒无助于提高其临界电流密度。 关键词：     

水／离子液体两相体系中出芽短梗霉催化4-氯-乙酰乙酸乙酯不对称还原合成（S）-4-氯-3-羟基-丁酸乙酯

考察了水/离子液体两相体系中出芽短梗霉(Aureobasidium pullulansCGMCC1244)催化4-氯乙酰乙酸乙酯(COBE)不对称还原生成光学活性(S)-4-氯-3-羟基丁酸乙酯((S)-CHBE)的性能,并对反应条件如摇床转速、相体积比、温度、初始底物浓度和pH值等进行了优化.结果表明,在水/1-丁基-3-甲基咪唑六氟磷酸盐体系中,出芽短梗霉催化COBE不对称还原生成(S)-CHBE,在30℃,pH6·6,摇床转速180r/min和不对称反应8h条件下,反应物的转化率、产物ee值和浓度分别达到95·6%,98·5%和47·1g/L.在控制pH值为6·6的情况下,通过分添加底物可有效提高产物(S)-CHBE浓度至75·1g/L.     

Effect of Intra-Dot Coulomb Interaction on Andreev Reflection in Normal-Metal/Quantum-Dot/Superconductor System

We investigate the effect of intra-dot Coulomb interaction on the Andreev reflection in a normalmetal/quantum-dot/superconductor (N-QD-S) system with multiple levels in the quantum dot, in the regime where the intra-dot interacting constant is comparable to the energy gap of superconducting lead. By using nonequilibrium Green function method, the averaged occupation of electrons in the quantum dot and the Andreev reflection (AR) current are studied. Comparing to the case of non-interacting quantum dot, the system shows significant changes for the a two-step-like behavior; and the I-Vg shows two groups of peaks, separated by U and with equal heights, where Vg is the gate voltage and U denotes the intra-dot Coulomb interaction constant. (ii) For finite bias voltage, dips, superposed V ≥ U/2, extra AR current peaks occur between the two groups of the peaks. Besides, the properties of the heights of the AR current peaks are more complicated.``     

求MLE的间接方法

介绍了计算极大似然估计的间接方法.