TEM investigation of formation mechanism of monocrystal-thick b-oriented pure silica zeolite MFI film

The first direct transmission electron microscopic (TEM) observation has been carried out on the continuous monocrystal-thick b-oriented pure silica zeolite MFI films produced by in situ crystallization. The self-supporting film samples for TEM study were fabricated by dissolving the steel substrate with acid. This TEM study is free of those artifacts that are typically associated with TEM sample preparations, and allows us to investigate the "true" structure and texture of a very large area of the film and at the same time to focus at will on each individual zeolite crystal in the film. Abundant TEM information including crystallographic orientation relationships among crystals in the film (both out-of-plane and in-plane), grain boundaries, and each crystal grain was obtained. This TEM investigation provides direct unambiguous new evidence to support the homogeneous nucleation mechanism, by which the films form through homogeneous nucleation and crystal growth in the bulk to form equal-sized disk-shape crystals, followed by self-assembly of these crystals onto the substrate to produce a two-dimensional close-packed structure. The last stage of the film formation involves simultaneous space-limited growth and rotation of the individual crystals to realize the in-plane crystallographic control within the film.     

THERMODYNAMIC STUDY ON ADSORPTION OF AROMATIC SULFONIC ACIDS ONTO MACROPOROUS WEAK BASE ANION EXCHANGER FROM AQUEOUS SOLUTIONS

 The adsorption equilibrium isotherms of three aromatic sulfonic acid compounds, 2-naphthalenesulfonic acid, p-toluenesulfonic acid and p-chlorobenzenesulfonic acid, from aqueous solutions by macroporous weak base anion exchanger within the temperature range of 293 K-313 K were obtained. Several isotherm equations were correlated with the equilibrium data, and the experimental data was found to fit the three-parameter Redlich-Peterson equation best within the entire range of concentrations. The study showed that the hydrophobicity of solute has distinct influence on adsorption capacity of the anion exchanger for the aromatic sulfonic acid. Moreover, estimations of the isosteric enthalpy, free energy,and entropy change of adsorption were also reported. The positive isosteric enthalpy and entropy change for adsorption indicate an endothermic and entropy driven process in the present study.     

表面热电离质谱的进展

本文评述了表面热电离质谱（ＴＩＭＳ），特别是负离子质谱（ＮＴＩ－ＭＳ）对非金属和具有高电离电位的金属元素的同位素测定的进展，引用文献３４篇。     

The first total synthesis of (-)-tamandarin A

[formula: see text] Tamandarin A (1), a newly isolated natural product similar in structure to didemnin B (2), was shown to be somewhat more active in vitro than 2 against pancreatic carcinoma with an ED50 value 1.5 to 2 ng/mL. We report here the first total synthesis of 1. The key steps include a practical stereoselective synthesis of the Hiv-isostatine unit, high-yielding linear precursor formation, a successful macrocyclization, and coupling of the macrocycle with the side chain to afford tamandarin A (1).     

反胶束笼对纳米氯化银反应性能的微环境限定

研究了反映束中直径为１０￣１７ｎｍ的ＡｇＣｌ微料与亚甲基蓝之间的作用，比较了阴离子型和非离子型表面活性剂组成的反胶束微环境的影响，讨论了亚甲基蓝在粒子上的吸附，二聚体形成的钠米ＡｇＣｌ粒子对亚甲基蓝荧光猝灭机制。     

氧化钨薄膜微型电化学器件的研究

本文论述了WO_3薄膜氢离子敏器件的结构、原理、制备技术和测试分析。利用WO_3薄膜在H+溶液中由绝缘转化为导电特性,成功地研制成氢离子敏器件。这是一种简易而经济的微型pH敏器件技术。     

Rearrangement with formamide extrusion in the electrospray mass spectra of aminoacylbenzylamines

Several aminoacylbenzylamines and their analogs were synthesized and analyzed by electrospray ionization mass spectrometry together with high-resolution and tandem mass spectrometric techniques. Fragment ions ([M + H - CH3NO](+)) were observed and attributed to a transfer of the benzyl group to the N-terminal amino group, leading to elimination of formamide. The proposed mechanism is supported by accurate mass measurements, and by experiments on deuterium labeling and variations of functional groups.     

Mesoporous silica nanospheres with the ability of photo-driven releasing sandela 803 for the application to wallpaper

Mesoporous silica nanospheres loaded with sandela 803 (S803@MS-S) are prepared for application to wallpaper. The nano-fragrance has high encapsulation efficiency and property of photo-driven release.     

大体积直接进样离子色谱法检测四甲基氢氧化铵中痕量阳离子

以抑制型电导离子色谱法检测四甲基氢氧化铵溶液中痕量碱金属和碱土金属离子.色谱条件为:IonPac CS12A阳离子交换色谱柱,20mmol/L甲烷磺酸淋洗液等度淋洗,抑制型电导检测.稀释液样品通过Dionex OnGuardⅡ氢型聚苯乙烯基强酸性树脂柱和0.22μm微孔尼龙膜处理.该方法的检测限(S/N=3)在0.024μg/L～0.156μg/L之间,标准曲线在低ng/L到低μg/L范围内呈现良好线性,RSD在10%左右,回收率为88%～115%.     

Stereoselective Synthesis of Piperamide Alkaloids by Modified Ramberg-Bcklund Reaction

A convenient and rapid approach for the synthesis of piperamide alkaloids la ~ h by the recently developed one-flask Ramberg-Backlund reaction was described. The synthesis of 1e was reported for the first time.