中草药中铁含量的测定与药效分析

为研究中草药中铁元素含量与心脑血管疾病的关系,选取红花、牛膝、首乌3种中草药,用盐酸羟胺为还原剂将三价铁还原为二价铁,在pH 4~6的条件下二价铁与邻二氮菲生成稳定的橘红色配合物,用721型分光光度计在波长为510 nm处直接测定了中草药中铁的含量。结果表明,牛膝中铁含量较高,为(2728.3750±34.3654)μg.g-1;首乌中铁的含量较低,为1493.437 5μg.g-1;红花中铁的含量适中,为(2344.770 8±17.3566)μg.g-1,3种中草药中铁的含量均有显著性差异(P<0.05)。测定结果为人们研究铁元素对心脑血管疾病的影响及合理开发利用中草药提供了科学依据。     

First Synthesis of （＋）-2,14-Deoxyalatol from α-Santonin

A novel and general approach for synthesis of the multi-oxygenated dihydrofuran sesquiterpenes has been developed starting from santonin. The key steps involve: the strategic acid-catalyzed double-bond shifting affording 4, the novel base-promoted epoxide rearrangement of 5 generating two key functionals (the C5-OH and the Δ^7,11 double bond), and the stereoselective cyclization of tetrahydrofuran ring without pre-controlling the stereochemistry of C-7. As an example of this approach, synthesis of ( )-2,14-deoxyalatol was described in detail.     

快度取值超环的可因式化散射矩阵与对称性算子

本文构造出了快度取值超环的可因式化散射矩阵及与其对易的算子一对称性算子,并在对易性保证的情况下,对s矩阵作了形式的推广,使之与杨-Baxter关系联系起来;值得注意的是,这种对称性算子的"余乘积"运算具有新的特点.最后给出了Z_N破缺模型与自对偶亏格为零极限下手征Potts模型的联系.     

Residual Stress on Surface and Cross-section of Porous Silicon Studied by Micro-Raman Spectroscopy

Surface and cross-sectional residual stresses of electrochemical etching porous silicon are investigated quantitatively by micro-Raman spectroscopy. The results reveal that a larger tensile residual stress exists on the surface and increase linearly with the porosity. On the other hand, across the depth direction perpendicular to the surface, the tensile residual stress decreases gradually from the surface to regions near the interface between the porous silicon layer and the Si substrate. However, a compressive stress appears at the interface near to the Si substrate for balancing with the tensile stress in the porous silicon layer. The cross-sectional residual stress profile is due to the porosity and lattice mismatch gradients existing in the cross-section and influencing each other.Furthermore, the presented residual stresses of the porous silicon have a close relation with its microstructure.     

基于BP神经网络的道路交通事故预测

道路交通事故预测是交通研究的一个重要课题.以我国交通安全状况为研究对象,依据我国道路交通事故的特点,利用神经网络具有自学习、自组织、自适应能力特性,运用神经网络的方法及我国多个年度道路交通事故统计数据,建立了道路交通事故神经网络宏观预测模型,预测精度符合道路交通事故预测的要求.     

Characteristics of a 4-fold segmented clover detectore

Four high-purity germanium 4-fold segmented Clover detectors have been applied in the experiment of neutron-rich nucleus 21N. The performance of those four Clovers have been tested with radioactive sources and in-beam experiments, and the main results including energy resolution, peak-to-total ratios, the variation of the hit pattern distribution in different crystals of one Clover detector with the energy of γ ray, and absolute full energy peak detection effciency curve, were presented.     

基于灰色关联的驾驶员驾驶失误分析

通过讨论驾驶员驾驶失误的影响因素,把驾驶失误系统看成是多因素的、关联的、整体的、复杂的灰色系统,从而用灰色关联分析法对驾驶失误系统进行因素分析.灰色关联度分析是通过对灰色系统中有限数据列的分析,寻求系统内部诸多因素之间的相互关系,找出影响目标值的主要因素,进而从总体上把握系统动态运动规律.     

固定化嗜热酯酶催化合成己酸乙酯

利用帆布固定化的嗜热酯酶APE1547在有机介质中催化已酸与乙醇完成酯化反应合成己酸乙酯.最佳反应条件为:c(己酸)=200 mmol·L-1,n(乙醇):n(已酸)=1.2:1.0,正己烷20 mL,加料速度0.4 mL.min-1,反应温度65℃,转化率85.2%.     

水平刻槽管壁面液体升膜非线性特性研究

水平刻槽管壁面升膜流动是一种低雷诺数流,低雷诺数流动的特点是惯性力与粘性力相比可以忽略不计,因此在求解Navier-Stokes方程时,常忽略对流项进行计算.本文通过采用一种级数解法,对含有对流项的Navier-Stokes方程进行逐级求解,分析不同雷诺数下含对流项的Navier-Stokes方程对速度解的影响.