薄层色谱法在香兰素合成中的应用

应用薄层色谱法对愈创木酚、3－甲氧基－4－羟基扁桃酸和香兰素进行了分析，以硅胶GF254作为吸附剂，从几种溶剂系统中选出氯仿：乙酸乙酯：正丙醇：冰乙酸：水＝20：1：1：1：2溶液作为展开剂。建立了 香兰素的薄层扫描定量分析方法，测定波长为500nm，参比波长为570nm，线性范围为0．31－6．2μg。     

大功率激光制备a-C和a-C∶H类金刚石膜的光学性能研究

采用大功率高重复频率准分子激光溅射热解石墨靶制备了类金刚石碳膜, 研究了实验条件对类金刚石膜光学性能的影响, 发现氢可以提高膜中sp3键的含量和膜的光学透过率. 在实验参数范围内, 膜的光学性能随着氢压的增加而提高. 根据类金刚石膜的反应沉积机理对上述结果进行了分析、解释.     

Enhancement of photocurrent generation by honeycomb structures in organic thin films.

A light-emitting poly (distyryldimethylbenzene-co-triethylene glycol) rod-coil block copolymer was used to fabricate films with three-dimensionally ordered honeycomb structures by the breath-figure method. Photocurrent generation and photovoltaic performance are studied, and the dependence of photocurrent on applied electric field is investigated. Introducing the ordered porous structure significantly improves the photoelectric conversion behavior, because porous structures not only enhance the light-harvesting efficiency but also benefit charge separation and charge transfer. This phenomenon may have great prospects for enhancing the photovoltaic behavior of organic thin-film devices.     

Zr（Y）O2衬底上大面积YBCO薄膜表面组织状态的研究

使用配备有ＥＤＳ和ＥＣＰ附件的ＳＥＭ、ＡＥＭ、和ＳＴＭ研究在７５０和８００℃的Ｚｒ（Ｙ）Ｏ２衬底上磁控溅射沉积的大面积ＹＢＣＯ超导薄膜的表面组织。ＹＢＣＯ薄膜为ｃ轴取向单晶，但衬底温度为８００℃时，膜表面的突出组织多为ＣｕＯ颗粒，小坑较多，表面粗糙；衬底温度为７５０℃时，突出组织多为棒状和多边形１２３结构，很少小坑，表面较平整。     

Thin‐Film Infrared Spectroscopy of Acetonitrile

Acetonitrile and [D₃]acetonitrile in the vicinal region of a planar AgX fiber contain linear dipole–dipole linked oligomers as shown by 1) comparison of infrared band intensity ratios in the gaseous and condensed phases and 2) remarkable plots of absorbance (C? N stretch) versus time during evaporation from an AgX planar fiber element. The plots (CH₃CN 2252 cm^?1, CD₃CN 2262 cm^?1) reveal the presence of octamers, hexamers, tetramers, and dimers along with some heptamer, trimer, and monomer structures. A novel isotope effect arises from the somewhat smaller size of the CD₃CN resulting in an increase in the CN band intensity. The organized oligomers may be termed pseudocrystals and are the main components responsible for absorption intensity in the infrared spectrum of acetonitrile, on the AgX planar fiber or in an IR cell.     

Electrochemistry of metallofullerene films: the major isomer of Dy@C82

Solution-cast films of the major isomer of Dy@C(82) (Dy@C(82)(I)) have been studied by cyclic voltammetry (CV) in acetonitrile. The films are found to display pronounced and stable redox responses in solution. The reduction/reoxidation processes exhibit large splittings between the first two reduction and reoxidation waves. However, a pair of reversible oxidation and rereduction waves is observed after the reoxidation of a reduced film. The characteristics and the inter-relationship of these waves are uncovered by the CV technique, scanning electron microscopy (SEM), and UV/Vis-NIR spectra. A possible mechanism is proposed for the film electrode processes, which emphasizes the redox-induced structural reorganization of the metallofullerene film by the incorporation and expulsion of electrolyte ions into and out of the film. The influence of the counter ion diffusivity and the ion-pair stability on the electrochemical activity of the metallofullerene film has also been indicated.     

Performance of the diffusive gradients in thin films technique for measuring Ca and Mg in freshwater

Measurements of the major cations Ca and Mg by the technique of diffusive gradients in thin films (DGTs) were systematically evaluated. The concentration in solution was calculated using Fick’s first law of diffusion from the directly measured flux to the DGT device. A selective cation exchange resin (Bio-Rad Chelex^®100), which has been used extensively with DGT for trace metals, such as Cd²⁺, Cu²⁺ and Ni²⁺, was used for this work.

Elution of Ca and Mg from the resin with 1 M HNO₃ was very reproducible. Measurements of Ca and Mg concentrations in synthetic solutions agreed well with the theoretical predictions. The negative response on uptake caused by lowered pH was investigated. Uptake was found to decline below pH 5. The capacity of the DGT device for Ca and Mg was also investigated to establish maximum deployment times for given concentrations.

Experiments with filtered and modified lake water show that DGT can be used to measure Ca and Mg when trace metals are present in the solution. An in situ deployment of DGT combined with an ultrafiltration study suggest that the Mg concentration measured by DGT is similar to the concentration found in the fraction <1 kDa.     

Plasma deposition of thin films from a fluorine-containing cyclosiloxane

Thin films have been deposited from radio-frequency glow discharges fed with vapors of a silicon- and fluorine-containing organic compound, namely 2,4,6-tris[(3,3,3-trifluoropropyl) (methyl)] cyclotrisiloxane, in mixture with argon. 2,4,6-tris[(3,3,3-trifluoropropyl)(methyl)]cyclotrisiloxane A triode reactor has been utilized to deposit films by independently changing substrate temperature and bias-induced ion-bombardment. Laser interferometry, electron spectroscopy for chemical analysis and Fourier-transform infrared spectroscopy have been used to monitor film growth rate and composition. Results unambiguously show an activating effect of the ion-bombardment, which confirm the validity of the ion-assisted deposition model utilized for the plasma deposition of both teflon- and silicone-like films. In our experiments, low substrate temperature and bias conditions results in films with a “monomer-like” stoichiometry, while drastic conditions give origin to materials with a completely different composition and a markedly increased hardness. © 1994 John Wiley & Sons, Inc.     

FTIR studies of polyimides. II. Factors affecting quantitative measurement

Measurement of imidization by IR spectroscopy has frequently been reported to give results that are either insensitive to changes in the latter part of the cure or in conflict with observations by other methods. However, an analysis of imide formation using the 1370 cm^?1 band (C? N stretch) in conjunction with the 1500 cm^?1 aromatic band as an internal standard appears capable of giving precise, internally consistent measurements for the most commonly used polyimide structures, for samples that are measured in transmission. Measurements of imide content in ultrathin films by grazing incidence reflection spectroscopy appear to be at least semiquantitative. © 1993 John Wiley & Sons, Inc.