Influences of dehydrating process on properties of ATO nano-powders

1　INTRODUCTIONCrystallineSbdopedtinoxide (ATO) ,cassiteritestructure ,isawidebandgapn typesemiconductor.Be causeofitsopticalproperty (transparentforvisiblelightandreflectiveforIR )andelectroconductibility ,goodchemicalandmechanicalstability ,ithasmanyapplica tions,suchastransparentconductiveelectrodes ,photo voltaicdevices ,photosensors ,catalyst,antistaticcoatingsandelectrochromicmaterials[14 ] .AvarietyoftechniqueshavebeenusedtoprepareATOsuperfinepowders ,someinvolvedryprocesses ,ot…     

磁性纳米SO4^2-／Fe3O4-ZrO2固体超强酸催化合成己二酸二正辛酯

利用磁性对纳米固体超强酸组合，制备出磁性纳米SO4^2-／Fe3O4-ZrO2固体超强酸催化剂，并用TEM、IR、Hammett指示剂检测磁性纳米固体超强酸催化剂性能。将其用于己二酸二正辛酯（DOA）的合成反应中。得到最佳反应条件为负压下，反应温度155℃，n（正辛醇）：n（己二酸）=3．2：1，反应时间2h，w（催化剂）=1．5％，己二酸的转化率达99％。利用催化剂的磁性可将纳米颗粒催化剂迅速分离，回收率达93．8％，并能重复使用。     

砂子负载纳米TiO2薄膜光降解有机污染物的研究

从光化学的角度，对砂子负载纳米二氧化钛薄膜，光催化剂降解工业污水中的有机污染物的过程进行分析与研究，探讨了多种因素对光降解的影响。实验显示在紫外光和纳米二氧化钛共同存在下，能对工业污水进行处理，砂子负载纳米二氧化钛进行光催化降解的最佳条件：纳米二氧化钛的质量分数为2％，焙烧温度约300℃，工业污水的pH为6．0～7．0。     

纳米钛酸锶钡粉体制备及其对水中Cd2+吸附行为

采用草酸盐化学共沉淀法制备了草酸氧钛锶钡前驱体,通过905℃高温煅烧,制得了高纯纳米钛酸锶钡,并利用SEM、TEM、FT-IR和XRD对其进行了表征;并将该粉体应用于水中重金属镉离子的吸附.结果表明：该法合成的钛酸锶钡粉体为球形,钙钛矿结构,平均粒径为36 nm.对水中的镉离子具有较强的吸附能力,其吸附量与介质的pH值有密切关系,吸附动力学符合Langmuir和Bangham速率方程所描述的规律;吸附等温线较好地符合Langmuir和Freundlich等温方程,吸附行为是自发的、放热的物理吸附过程.     

Preparation of novel porous starch microsphere foam for loading and release of poorly water soluble drug

Background: Organic porous material is a promising carrier for enhancing the dissolution of poorly water soluble drug. The aim of the present study was to enhance dissolution and oral bioavailability of lovastatin (LV) by preparing a porous starch microsphere foam (PSM) using a novel method, meanwhile, looking into the mechanism of improving dissolution of LV.

Methods: PSM was prepared by the W/O emulsion – freeze thawing method. The porous structure of PSM was characterized by scanning electron microscopy (SEM) and nitrogen adsorption/desorption analysis. The adsorption role of nanopores on the drug dissolution and physical state of LV was systematically studied by instrumental analysis, and in vitro and in vivo drug dissolution studies. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to evaluate carrier cytotoxicity.

Results: The SEM images of PSM showed nanometer-sized pores. Physical state characterization indicated that porous structure effectively limited the degree of crystallinity of LV. The results of in vitro and in vivo tests testified that PSM accelerated the release of LV and enhanced its oral bioavailability in comparison with crude LV and commercial capsules. The loaded PSM powder indicated a good physical stability under storage for 12 months. MTT assay shows PSM has no toxicity for Caco-2 cell.

Conclusion: The preparation was a promising method to produce small and uniform PSM with markedly enhanced dissolution rate and oral bioavailability due to the spatial confinement effect of porous structure. The present work demonstrates the significant potential for the use of PSM as a novel delivery system for poorly water soluble drugs.     

碱式碳酸锌热分解机理及动力学

采用TG、DTA、DTG等热分析手段研究了碱式碳酸锌热分解过程，热分析研究结果显示, Zn5(CO3)2·(OH)6为一步分解而得到纳米氧化锌，研究得到的机理模型证明其热分解过程符合随机核化机理。利用XRD，TEM等测试手段对纳米氧化锌的结构和形貌进行了表征，结果表明，通过Zn5(CO3)2·(OH)6热分解方法可以获得结晶性及分散性良好、粒径分布窄、粒度约为10 nm左右的纳米氧化锌。     

超细三氧化钨的制备及催化应用

介绍了近年来国内外对WO3粉体、薄膜及介孔三氧化钨的制备方法和研究进展,以及三氧化钨催化剂的应用,并对WO3催化剂今后的研究发展提出了一些看法。     

Influence of Mo on Growth and Coarsening of Nanometer-sized Carbides in Low-alloy Ferritic Steels Containing Ti

By optical microscopy, transmission electron microscopy and energy dispersive spectroscopy, the changes with aging time in size, composition and distribution of nanometer-sized （Ti, Mo）C precipitated in Ti-Mo low-alloy ferritc steel have been studied in comparison with that of nanometer-sized TiC precipitated in Ti low-alloy ferritc steel. It was found that the growth rate of （Ti,Mo）C in Ti-Mo steel was less than that of TiC in Ti steel. Nanometer- sized carbides formed at 650 ~C （or 550 ~C） for 55 h were at transitional stage from growth to coarsening. When aging time reaches 55 h, the coarsening rates of nanometer-sized carbides in Ti and Ti-Mo steel tend to be the same and in- variable. The influence of Mo on growth and coarsening of nanometer-sized carbides tends to decrease with increasing aging time, and Mo contents in nanometer-sized carbides with the same size at different aging time were different.     

Ti-V-Mo微合金化22MnB5钢中析出相及其强化作用

使用温成形替代热成形可以避免热成形过程中表面氧化等问题,但热成形常用22MnB5钢在高温回火后出现明显的软化现象.而通过向钢中添加Ti、V、Mo等微合金元素可以在钢中形成细小的析出相以及细化晶粒,起到提高强度的作用,从而可以解决该问题.因此,通过在22MnB5钢中添加Ti、V、Mo微合金元素,利用OM(光学显微镜)、F...     

纳米Z_rO_2超细粉的制备及表面改性

通过加入适宜的分散剂,采用共沉淀法制备了纳米级ＺｒＯ２超细粉,其粒度分布均匀,且分散性好,所得粉体进行了表面改性,使粉体表面由极性转变为非极性。