Comparative study on the inclusion behavior between meso-tetrakis(4-N-ethylpyridiniurmyl)porphyrin and beta-cyclodextrin derivatives

5,10,15,20-Tetrakis(4-N-ethylpyridiniurmyl)porphyrin (TEPyP) formed 1:1 stoichiometry inclusion complexes with beta-cyclodextrin (beta-CD) and its derivatives including hydroxypropyl-beta-cyclodextrin (HP-beta-CD), sulfobutylether-beta-cyclodextrin (SBE-beta-CD) in basic aqueous solution. The supramolecular system was investigated by the methods of fluorescence, UV-vis absorption spectroscopy, nuclear magnetic resonance (NMR) technique. The inclusion ability of cyclodextrins exhibited remarkable difference for beta-CD, HP-beta-CD and SBE-beta-CD. Association constants as high as K=1.1 x 10(4) M(-1) in the case of HP-beta-CD/TEPyP and 2.0 x 10(5) M(-1) in the case of SBE-beta-CD/TEPyP complexes were determined, whereas a lower value (K=550 M(-1)) was given in the case of beta-CD/TEPyP. The results showed that hydrogen bonding and charge attraction play important roles in the processes of host-guest interaction. The interaction mechanism of inclusion processes could be explained by the analysis of NMR spectroscopy. The supramolecular assembly was formed. beta-CD and HP-beta-CD approached from the primary face of cavities of CDs.     

Study on inclusion interaction of piroxicam with beta-cyclodextrin derivatives

The inclusion behavior of piroxicam (PX) with beta-cyclodextrin (beta-CD), hydroxypropyl-beta-cyclodextrin (HP-beta-CD), and carboxymethyl-beta-cyclodextrin (CM-beta-CD) was investigated by using steady-state fluorescence and nuclear magnetic resonance (NMR) technique. The various factors affecting the inclusion process were examined in detail. The remarkable fluorescence emission enhancement upon addition of CDs suggested that cyclodextrins (CDs) were most suitable for inclusion of the uncharged species of PX. The stoichiometry of the PX-CDs inclusion complexes was 1:1, except for beta-CD where a 1:2 inclusion complex was formed. The formation constants showed the strongest inclusion capacity of beta-CD. NMR showed the inclusion mode of PX with CDs.     

Synthesis and properties of silicon dioxide films prepared by pulsed laser deposition using ceramic SiO2 target

Silicon dioxide (SiO₂) thin films were deposited on BK7 substrates by pulsed laser deposition (PLD) method using ceramic SiO₂ targets (C-SiO₂-Ts), which was sintered by solid state sintering. The reason for using C-SiO₂-T instead of the silicon target is to reduce the oxygen-deficiency phenomenon in deposited SiO₂ thin films. The influence of substrate-temperatures, oxygen-pressures and oxygen-plasma-assistance on the properties of synthesized films was studied. X-ray diffraction, atomic force microscopy, ultraviolet–visible–near-infrared scanning spectrophotometry were used to characterize the crystallinity, morphology and optical properties of deposited films. Results show that the root-mean-square roughness of films increased with the increase of oxygen-pressure, substrate-temperature and with the employment of oxygen-plasma. The transmittance of films increased with the increase of oxygen-pressure and decreased with the increase of substrate-temperature and with the employment of oxygen-plasma. Stoichiometric SiO₂ thin film with high optical quality was synthesized at room-temperature and 20 Pa oxygen-pressure using C-SiO₂-T.     

紫外光下纳米TiO2薄膜亲水性机理的电化学研究

利用溶胶 凝胶方法在透明导电玻璃ITO (SnO2 ∶In)表面制备纳米TiO2 薄膜 ,XRD谱图表明TiO2 是锐钛矿晶型 ,AFM (Atomic Force Microscope)测得薄膜表面粒子约为 10 0nm .研究了ITO表面纳米TiO2 薄膜的光致亲水性变化 .通过循环伏安技术测定TiO2 薄膜电极在 2 5 3.7nm的紫外光照射后的电化学行为推测光致亲水性机理 .发现在紫外光照射一定时间后 ,TiO2 薄膜电极的循环伏安图在 +0 .0 35V处出现新的氧化峰 ;且随光照时间的增加 ,氧化峰的峰电流增大 ,溶液中的溶解氧对峰电流的大小有明显影响 .实验表明 ,在紫外光照下电极表面有Ti3 + 产生 ,证实了TiO2 薄膜的光致亲水性转变过程与Ti3 + 的生成导致的表面结构变化有关     

氧化石墨烯/羟基磷灰石复合材料对酸蚀牛牙釉质体外再矿化的影响

考察不含氧化石墨烯(GO)的羟基磷灰石(HAP)和含GO质量分数为0.1;的氧化石墨烯/羟基磷灰石复合材料(GO/HAP)对酸蚀牛牙釉质体外再矿化的影响.通过场发射扫描电镜、EDX能谱、X射线衍射仪和维氏显微硬度测试仪,对再矿化前/后牛牙釉质表面和剖面形貌、表面元素、晶体结构和力学性能进行表征.结果 表明:GO/HAP复合材料在酸蚀牙釉质表面生成了结合力较弱的花状晶体,将这些晶体超声剥离后发现脱矿釉质表面和釉柱间隙均得到良好的修复.剖面形貌分析显示,GO/HAP复合材料使釉质深层脱矿得到良好修复,促进了牙釉质棱晶间大量微小晶粒的生成,以及脱矿釉柱间隙中有序排列晶体的生成.同时,经GO/HAP处理后,酸蚀牙釉质表面的Ca/P摩尔比和晶体成分均得到良好的恢复.     

Optimization-based structure identification of dynamical networks

The topological structure of a dynamical network plays a pivotal part in its properties, dynamics and control. Thus, understanding and modeling the structure of a network will lead to a better knowledge of its evolutionary mechanisms and to a better cottoning on its dynamical and functional behaviors. However, in many practical situations, the topological structure of a dynamical network is usually unknown or uncertain. Thus, exploring the underlying topological structure of a dynamical network is of great value. In recent years, there has been a growing interest in structure identification of dynamical networks. As a result, various methods for identifying the network structure have been proposed. However, in most of the previous work, few of them were discussed in the perspective of optimization. In this paper, an optimization algorithm based on the projected conjugate gradient method is proposed to identify a network structure. It is straightforward and applicable to networks with or without observation noise. Furthermore, the proposed algorithm is applicable to dynamical networks with partially observed component variables for each multidimensional node, as well as small-scale networks with time-varying structures. Numerical experiments are conducted to illustrate the good performance and universality of the new algorithm.     

Stochastic Volterra equations driven by fractional Brownian motion

This paper is devoted to study a class of stochastic Volterra equations driven by fractional Brownian motion. We first prove the Driver type integration by parts formula and the shift Harnack type inequalities. As a direct application, we provide an alternative method to describe the regularities of the law of the solution. Secondly, by using the Malliavin calculus, the Bismut type derivative formula is established, which is then applied to the study of the gradient estimate and the strong Feller property. Finally, we establish the Talagrand type transportation cost inequalities for the law of the solution on the path space with respect to both the uniform metric and the L₂-metric.     

场效应晶体管生物传感器

综述了场效应晶体管生物传感器的研究进展。介绍了场效应晶体管生物传感器的原理、分类及其生物功能物质的固定化技术,并探讨了其存在的问题和发展趋势。     

Structure, morphology and optical properties of SiO2−x thin films prepared by plasma-assisted pulsed laser deposition

The amorphous silicon oxide SiO_2−x thin films were prepared by the plasma-assisted pulsed laser deposition (PLD) method. X-ray diffraction spectrometry (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), UV-VIS-NIR scanning spectrophotometry and ellipsometry were used to characterize the crystallinity, microscopic morphology and optical properties of obtained thin films. The influences of substrate temperatures, oxygen partial pressures and oxygen plasma assistance on the compositions of silicon oxide (SiO_2−x) thin films were investigated. Results show that the deposited thin films are amorphous and have high surface quality. Stoichiometric silicon dioxide (SiO₂) thin film can be obtained at elevated temperature of 200 °C in an oxygen plasma-assisted atmosphere. Using normal incidence transmittance, a novel and simple method has been proposed to evaluate the value of x in transparent SiO_2−x thin films on a non-absorbing flat substrate.     

大学物理演示实验教学中存在的几个突出问题

本文结合调查和教学实践，论述了演示实验教学的重要性，指出了演示实验教学和管理中存在的几个突出问题，并提出了自己的一些看法．