含氮杂环化合物理化性质和生物活性的QSPR/QSAR分析

在分子拓扑理论的基础上,计算了含氮杂环化合物的3类拓扑指数:分子连接性指数、形状指数和分子电性距离矢量.利用多元线性回归的方法建立了含氮杂环化合物的疏水性参数(lgP)和对淡水纤毛虫毒性(-lgc)的QSPR/QSAR(定量结构-性质/活性相关)模型,相关系数分别为0.998 1和0.980 6.模型经Jackknife法和逐一剔除法(LOO)交互检验证明具有良好的稳健性和预测能力,为了进一步提高相关系数0.980 6模型的相关性,以模型中的3个参数为人工神经网络输入层,设定3∶3∶1的网络结构,构建人工神经网络(BP)算法模型,相关系数R提升为0.993 3.该模型能很好地预测含氮杂环化合物的理化性质和生物活性.     

Single photon transport properties in coupled cavity arrays nonlocally coupled to a two-level atom in the presence of dissipation

We discuss the effects of dissipation on the behavior of single photon transport in a system of coupled cavity arrays,with the two nearest cavities nonlocally coupled to a two-level atom.The single photon transmission amplitude is solved exactly by employing the quasi-boson picture.We investigate two different situations of local and nonlocal couplings,respectively.Comparing the dissipative case with the nondissipative one reveals that the dissipation of the system increases the middle dip and lowers the peak of the single photon transmission amplitudes,broadening the line width of the transport spectrum.It should be noted that the influence of the cavity dissipation to the single photon transport spectrum is asymmetric.By comparing the nonlocal coupling with the local one,one can find that the enhancement of the middle dip of single photon transmission amplitudes is mostly caused by the atom dissipation and that the reduced peak is mainly caused by the cavity dissipation,no matter whether it is a nonlocal or local coupling case.Whereas in the nonlocal coupling case,when the coupling strength gets stronger,the cavity dissipation has a greater effect on the single photon transport spectrum and the atom dissipation affection becomes weak,so it can be ignored.     

化学改性豆油的烷链结构和摩擦学性能研究

本文对豆油进行了化学改性,豆油环氧后和不同链长的脂肪酸进行酯化反应,生成一系列的改性豆油并对其结构进行表征;考察了不同烷链结构的改性豆油的摩擦学性能,结果表明所合成的系列改性豆油有优良的摩擦学性能,随着直链酸链长的不同黏度也不同,黏度越大润滑性能越好,其中乙酯和丙酯的黏度最大、润滑性能最好,摩擦学性能远远优于豆油和光亮油150BS,归因于豆油异构乙酯和丙酯含有极性基团,且分子中氧的含量较高,易生成吸附膜和氧化反应保护膜.豆油异构丙酯倾点最低,其黏度高,可以代替紧缺的光亮油和低黏度油调配成多种不同黏度级别的润滑油.豆油异构丙酯与聚醚调配的各黏度级别的润滑油的倾点明显低于同级别矿物油,摩擦学性能优于同级别矿物油,氧化稳定性也远远优于矿物油,可用作高档次的合成润滑油.试验结果表明用本工艺改善植物油的氧化稳定性和润滑性行之有效.     

Structural Determination,Unstable Antiferromagnetism and Transport Properties of Fe-Kagome Y0.5Fe3Sn3 Single Crystals

Kagome materials have been studied intensively in condensed matter physics.With rich properties,various Kagome materials emerge during this process.Here,we grew single crystals of Y_0.5Fe₃Sn₃ and confirmed an YCo₆Ge₆-type Kagome-lattice structure by detailed crystal structure characterizations.This compound bears an antiferromagnetic ordering at T_N = 551 K,and shows a weak ferromagnetism at low temperatures,where an anomalous Hall ...