聚甲基丙烯酸甲酯间隔的金纳米立方体与金膜复合结构的表面增强拉曼散射研究

金属纳米颗粒与金属薄膜的复合结构由于其局域表面等离子体和传播表面等离子体间的强共振耦合作用,可作为表面增强拉曼散射(SERS)基底,显著增强吸附分子的拉曼信号.本文提出了一种聚甲基丙烯酸甲酯(PMMA)间隔的90 nm金纳米立方体与50 nm金膜复合结构的SERS基底,通过有限元方法数值模拟,得到PMMA的最优化厚度为15 nm.实验制备了PMMA间隔层厚度为14 nm的复合结构,利用罗丹明6G (R6G)为拉曼探针分子, 633 nm的氦氖激光器作为激发光源,研究了复合结构和单一金纳米立方体的SERS效应,发现复合结构可以使探针分子产生比单一结构更强的拉曼信号.在此基础上,研究了不同浓度金纳米立方体水溶液条件下复合结构中R6G的拉曼光谱.结果表明,当金纳米立方体水溶液浓度为5.625μg/mL的条件下复合结构中R6G的拉曼信号最强,且可测量R6G的最低浓度达10~(–11) mol/L.     

Syntheses,structures and magnetic properties of three cobalt(II) coordination polymers based on flexible itaconic acid ligands

Transition Metal Chemistry - Three Co(II) coordination polymers, namely [Co(ia)(bpe)0.5(H2O)]n (1), {[Co(ia)(bib)(H2O)]·H2O}n (2) and {[Co(ia)(btmb)(H2O)]·H2O}n (3)...     

正交信号校正在人体血糖近红外光谱分析中的研究

本文以血清的近红外光谱为研究对象,首先运用载荷向量分析确定最佳定标谱区为4192-4943 cm-1与5294-7200 cm-1两个波段,然后分别用平滑、一阶导数、正交信号校正(OSC)预处理方法,结合偏最小二乘回归方法建立了血清中血糖的模型.用平滑、一阶导数所建立模型的预测标准偏差(RMSEP)分别是0.545、0.568,用OSC校正后所建立模型的RMSEP是0.390,结果表明使用OSC校正对光谱进行合理的校正,能够滤除光谱矩阵与浓度矩阵无关的信号,降低模型的因子数,从而降低模型的复杂性,提高模型的稳健性.     

Generalized projective synchronization of chaotic systems via adaptive learning control

In this paper, a learning control approach is applied to the generalized projective synchronisation (GPS) of different chaotic systems with unknown periodically time-varying parameters. Using the Lyapunov--Krasovskii functional stability theory, a differential-difference mixed parametric learning law and an adaptive learning control law are constructed to make the states of two different chaotic systems asymptotically synchronised. The scheme is successfully applied to the generalized projective synchronisation between the Lorenz system and Chen system. Moreover, numerical simulations results are used to verify the effectiveness of the proposed scheme.     

理想条件下氡及其子体运移新理论及其运移方程

论述了氡及其子体运移的新理论,认为氡及其子体在垂直方向的运移机理是氡及其子体经α 衰变所放出的α粒子减速后，将成为He核，He核可与氡及其子体形成团簇，当团簇在介质中 所受的浮力大于其重量时，团簇便能自行向上运移，否则团簇就向下运移.在此理论基础上 建立了氡运移理论分布方程，并对运移方程进行了验证. 关键词： 团簇 氡运移 运移方程     

Brown反应特例及机理初探

报道了一例非Brown反应类型. 3-甲氧基-3,5,17(20)-雄甾三烯(1)用乙硼烷或9-BBN处理时, 没有进行Brown反应生成3-甲氧基-3,5-三烯-17β-羟甲基雄甾(2), 而是发生了17(20)碳碳双键的断裂, 得到3-甲氧基-3,5-二烯-17β-羟甲基雄甾(3). 对于该反应的机理, 进行了初步探讨.     

Modification of the Wiener index 4

A novel topological index W(F) is defined by the matrices X, W, and L as W(F) = XWL. Where L is a column vector expressing the characteristic of vertices in the molecule; X is a row vector expressing the bonding characteristics between adjacent atoms; W is a reciprocal distance matrix. The topological index W(F), based on the distance-related matrix of a molecular graph, is used to code the structural environment of each atom type in a molecular graph. The good QSPR/QSAR models have been obtained for the properties such as standard formation enthalpy of inorganic compounds and methyl halides, retention indices of gas chromatography of multiple bond-containing hydrocarbons, aqueous solubility, and octanol/water partition of benzene halides. These models indicate that the idea of using multiple matrices to define the modified Wiener index is valid and successful.     

A new benzodioxocinone from the leaves of Cinnamomum tenuifolium

Investigation of the leaves' extract of Cinnamomum tenuifolium (Lauraceae) led to the isolation of one novel benzodioxocinone, 2,3-dihydro-6,6-dimethylbenzo-[b][1,5]dioxocin-4(6?H)-one (1). The structure was determined through in-depth spectroscopic and mass-spectrometric analyses. The antioxidant potential was evaluated using the following in?vitro method: scavenging of 1,1-diphenyl-2-picrylhydrazyl radical. We also detected the anti-proliferative effect of 1 on human oral cancer cells and its IC(50) is 107.7?μM.