电化学STM技术在金属腐蚀科学中的应用及研究进展

本文介绍了电化学STM在金属腐蚀电化学研究领域的技术优势.其最大特点是可以在金属腐蚀环境中和原子/分子水平上,实时、原位、三维空间观察,并可以通过电位控制表面电极过程.综述了电化学STM在钝化膜结构、缓蚀剂的自组装膜、金属表面原子的活性溶解等揭示腐蚀缓蚀机理的研究领域中所起的重要作用以及最新研究进展.     

硫化锰夹杂溶解和微生物存在对不锈钢管发生点蚀

结合发电厂凝汽器不锈钢管内壁腐蚀部位分布规律和腐蚀外貌特征,分别对腐蚀部位沉积物、内壁蚀孔附近管材成分进行扫描电子显微镜观察和能谱分析,探讨了管材中MnS溶解与微生物对凝汽器不锈钢管腐蚀的电化学反应机理,发现二者在点蚀形成过程中具有协同作用,并在综合分析影响不锈钢腐蚀的各种因素的基础上,提出了不锈钢凝汽器在运行过程中应采取的防护措施。     

The effect of hydrogen bond acceptor properties of ionic liquids on their cellulose solubility

It is nowadays well-known that ionic liquids can dissolve cellulose. However, little systematic data has been published that shed light onto the influence of the ionic liquid structure on the dissolution of cellulose. We have conducted 1H NMR spectroscopy of ethanol in a large number of ionic liquids, and found an excellent correlation of the data obtained with the hydrogen acceptor properties (β-values). With this tool in hand, it is possible to distinguish between cellulose-dissolving and non-dissolving ionic liquids. A modulating effect of both, the anion of the non-dissolving ionic liquid and its cation was found in solubility studies with binary ionic liquid mixtures. The study was extended to other non-dissolving liquids, namely water and dimethylsulfoxide, and the effect of the cation was also investigated.     

氯柱硼镁石的合成及其在20℃水中的溶解相转化动力学研究

报道了合成氯柱硼镁石的快捷方法及该复盐在20℃水中的溶解和相转化过程.结果表明:该复盐在水中呈现不同步溶解,首先溶脱掉MgCl2·6H2O,生成中间产物MgO·B2O2·4H2O,随后发生转化,最终转化产物是2MgO·3B2O2·15H2O.拟合出了溶解转化结晶动力学方程,提出了溶解转化结晶反应机制.     

铁矿粉化学热加工中亚铁含量的测定

提出了一种铁矿粉热加工生产工艺中亚铁含量测定的新方法。在氮气保护下，用盐酸溶出样中的亚铁，在硫磷混酸介质中以重铬酸钾标准溶液滴定，并对溶样条件进行了研究。该方法简单、快速、准确，已成功地应用于氧化催化法生产氧化铁中亚铁的控制分析和成品鉴定。     

Enhancement of Oral Bioavailability of Rofecoxib Using β-Cyclodextrin

The purpose of the present work was to investigate the effect ofcomplexation of rofecoxib with -cyclodextrin on its dissolutioncharacteristics and bioavailability. Inclusion complexes of rofecoxibwith -cyclodextrin were made by freeze-drying technique. Phasesolubility studies were conducted as suggested by Higuchi and Connors.The samples were characterized by performing dissolution studies, X-rayDiffraction studies and Differential Scanning Calorimetry. The complexeswere compressed into tablets and compared in-vitro with various marketedformulations. A single dose study on healthy human volunteers was performedin comparison with a marketed formulation of rofecoxib (without-cyclodextrin) to investigate the relative bioavailability.Phase solubility studies confirmed the formation of a 1 : 1complex in solution of rofecoxib with -cyclodextrin. Tablets ofsolid inclusion complexes of rofecoxib with -cyclodextrin preparedby freeze drying technique showed enhanced dissolution rate in distilledwater in comparison with all the marketed formulations analyzed. This isattributed to the increased solubility and wettability along with decreasedcrystallinity caused by complex formation, which is confirmed, by XRD and DSCstudies. The bioequivalence studies performed showed statistically significantenhancement in bioavailability as compared to the marketed formulation.Apparently, tablets containing complexes of rofecoxib with -cyclodextrinshows faster onset of action due to improved solubility, enhanced dissolutionand faster absorption of the molecule. The results of this investigation withrofecoxib in -cyclodextrin lend ample credence to its better oralbioavailability on complexation.     

SYNTHESIS OF CONDUCTIVE POLYANILINE VIA OXIDATION BY MnO2

A unique process of chemical oxidation polymerization of aniline using manganese dioxide (MnO2) as the oxidizing agent in an aqueous medium is described. The reaction between aniline and MnO2 follows a mechanism by which the organic monomer is oxidized while the metal oxide undergoes reductive dissolution. The effects of the amount of oxidizing agent and aniline, pH and temperature of the reactive system, type of acid on the yield and conductivity of polyaniline are discussed. The resulting polyaniline was characterized by [R and UV-Vis spectrometry. Polyaniline with a conductivity of 12.5 S/cm was obtained using 0.033 tool of aniline oxidized by 0.023 tool MnO2 in the presence of 100 mL of 2.7 mol/L HCI at 25℃ for 4 h.     

I-Line光刻胶材料的研究进展

酚醛树脂-重氮萘醌正型光刻胶由于其优异的光刻性能,在g-line(436 nm)、i-line(365 nm)光刻中被广泛使用.g-line光刻胶胶、i-line光刻胶,两者虽然都是用线型酚醛树脂做成膜树脂,重氮萘醌型酯化物作感光剂,但当曝光波长从g-line发展到i-line时,为适应对应的曝光波长以及对高分辨率的追求,酚醛树脂及感光剂的微观结构均有变化.在i-line光刻胶中,酚醛树脂的邻-邻'相连程度高,感光剂酯化度高,重氮萘醌基团间的间距远.溶解促进剂是i-line光刻胶的一个重要组分,本文对其也进行了介绍.     

Metal Ion Guest Responsive Benzoxazine Dimers and Inclusion Phenomena of Cyclic Derivatives

This study was carried out with the aim to optimize the dissolution propertiesof diclofenac (DIC) – a non-steroidal anti-inflammatory drug sparingly solublein water – through association -with -cyclodextrin (CD). Theeffect of CD on the aqueous solubility of DIC was evaluated by thephase solubility method. The amount of DIC dissolved increased linearly withthe addition of CD according to an AL type plot and without precipitationof the complex. The apparent stability constant of the complex, calculated supposinga 1:1 stoichiometry, was 295 M^-1; this value was confirmed by circulardichroism analysis. DIC/CD interactions were also studied in water by¹H and ¹³C NMR spectroscopy. Equimolar DIC/CD solid systems were prepared by physical-mixing, kneading, co-evaporation andfreeze-drying, and their properties in the solid state studied by DifferentialScanning Calorimetry, X-ray powder diffractometry and Fourier-TransformInfrared analysis. For sake of comparison, the mixture of DIC and CDseparately lyophilized was investigated too. The results demonstrated that thefreeze-dried product had the highest degree of amorphization and they were inagreement with the existence of an inclusion complex in the solid state. Thedissolution profiles of the drug from each solid system were affected by its physico-chemical properties, the freeze-dried being the most rapidly dissolvingforms.     

二氧化氮溶于水定量实验的设计与研究

设计了NO2溶于水的定量实验。实验发现,把装满NO2的试管倒立于水中,待数分钟后试管内液面基本稳定,此时管内液体上升的体积远大于试管容积的2/3,若等待时间足够长(14 h),液体可充满整个试管。进一步研究表明,造成这种现象的可能原因,一方面与制取NO2时浓硝酸的饱和蒸气压有关,另一方面与NO自身溶于水并与水溶氧反应有关,还与NO能溶于稀硝酸有关,而与NO2的二聚无关。液体能充满整个试管可能应与氧气在水中的扩散有紧密关系。