溶胶-凝胶法制备纳米平整度的四钛酸钾薄膜

以Ti(n-OC₄H₉)₄和CH₃COOK为前驱体, 采用溶胶-凝胶法在载玻片上制得纳米平整度的四钛酸钾致密薄膜, 并用原子力显微镜(AFM)分析了薄膜的表面结构. 运用TG和XRD研究了四钛酸钾的生成过程. 在四钛酸钾薄膜上进行十八烷基三氯硅烷(OTS)的自组装, 通过测量自组装单分子膜(SAMs)因光催化分解而导致接触角变化研究薄膜的光催化性能. 结果表明: 薄膜由纳米颗粒组成, 扫描范围为2μm×2μm的AFM图的均方根粗糙度(RMS)仅为4.1nm; 四钛酸钾薄膜上形成的致密OTS单层膜的质量与在TiO₂薄膜上相似, 该薄膜具有较强的光催化能力.     

平整二钛酸钾薄膜的制备及其气相光催化活性

采用溶胶-凝胶法制备了K2Ti2O5薄膜并进行表征;在K2Ti2O5薄膜表面上形成致密的十八烷基三氯硅烷(C18H37SiCl3,OTS)单层自组装膜(SAMs);用OTS SAMs 水接触角变化研究薄膜的气相光催化活性;测量了薄膜的光电流响应.研究发现:K2Ti2O5薄膜表面平整、均匀、致密、在玻璃基片上透明;在紫外和可见光区都有光吸收;K2Ti2O5薄膜上OTS SAMs在空气中用254nm的紫外光照射时降解速度比在TiO2薄膜上快;K2Ti2O5薄膜产生阳极光电流,比TiO2薄膜具有更强的光激发和更稳定的光电流响应.结果表明,K2Ti2O5薄膜在空气中用紫外光照射能很有效的分解OTS SAMs,是一种很好的治理气相有机污染物的光催化剂.     

钛酸镧铅薄膜的介电、铁电性能研究

采用溶胶－凝胶法在Si衬底上制备了钛酸镧铅薄膜。通过对膜进行XRD、SEM、介电和铁电性能测试,研究了退火条件和掺镧量对薄膜性能的影响,结果发现在600℃下退火1h的PLT薄膜呈现钙钛矿结构;常温下,薄膜的矫顽场和剩余极化强度都随着掺镧量的增加而降低,其介电常数和介质损耗却随掺镧量的增加而增大。     

纳米TiO2薄膜的制备及其光催化性能研究

采用溶胶-凝胶(Sol-gel)法在玻璃衬底上制备了纳米TiO2薄膜.采用X射线衍射仪(XRD)、紫外可见一光谱(UV/vis)和原子力显微镜(AFM)对纳米TiO2进行表征.结果表明,经300～700℃退火得到的TiO2粉体呈锐钛矿相,经800℃退火得到了锐钛矿相与金红石相的混合晶相,经900℃退火完全转化为金红石相.薄膜表面粒子分布均匀,表面平均粗糙度为1.54nm,该薄膜具有较高的光催化活性,可直接用于光催化降解有机物等领域,具有广阔的应用前景.     

高掺银-钛酸铅复相薄膜的制备研究

采用溶胶-凝胶法, 通过在新鲜溶胶和在陈化溶胶中分别高掺银这两种制备工艺过程, 制备了分散均匀的立方相银颗粒-钛酸铅相基质复相薄膜. 利用XRD, SEM, TEM等方法对先驱体溶胶和薄膜的组成与结构进行了测试. 研究表明, 溶胶中Ag的存在形式直接对薄膜的晶相形成过程产生影响. 当银以Ag⁺的形式存在于溶胶中时, 银优先消耗部分铅析出银-铅合金相, 体系含银量较少时形成焦绿石相钛酸铅, 含银量较多时, 形成固溶有银的钙钛矿相钛酸铅; 当银以银团簇的形式存在于溶胶中时, 薄膜中直接形成钙钛矿相钛酸铅晶相.     

溶胶-凝胶法合成锆钛酸铅陶瓷材料及其特性研究

以丁醇钛、乙醇锆、醋酸铅为原料,采用溶胶-凝胶新工艺,成功地制备出锆钛酸铅陶瓷材料。本文主要对成胶规律.粉末的特性及陶瓷材料的电性能进行了研究。结果表明:用溶胶一凝胶法制备的陶瓷粉料具有纯度高,合成温室低等特点,由此所制备的陶瓷样品具有优良的介电和压电性能。     

离子交换法制备钛酸钾纳米纤维及其表征

采用离子交换法,以KOH溶液与钛酸纳米管（H2Ti2O4（OH）2）反应,制备了钛酸钾纳米纤维。透射电镜（TEM）和X-射线衍射分析（XRD）结果表明,经过离子交换,形貌由纳米管变为纳米纤维,晶体结构亦发生改变。利用原子吸收分光光度法、比色法和X-射线光电子能谱（XPS）对离子交换产物的Ti、K元素的原子比和化学价态进行分析,结果表明,离子交换产物的经验式为：K1.34H0.66Ti2O4（OH）2。与H2Ti2O4（OH）2纳米管相比,钛酸钾纳米纤维的热稳定性较好,700℃以上的热处理才使其晶型发生改变,出现单斜型的K2Ti4O9。高温处理导致钛酸钾纳米纤维的直径增加,但仍保持较大长径比。该材料的BET比表面为104m2·g^-1。     

离子交换法制备钛酸钾纳米纤维及其表征

采用离子交换法, 即以KOH溶液与钛酸纳米管(H₂Ti₂O₄(OH)₂)反应, 制备了钛酸钾纳米纤维. 透射电镜(TEM)和X射线衍射分析(XRD)结果表明, 经过离子交换, 形貌由纳米管变为纳米纤维, 晶体结构亦发生改变. 利用原子吸收分光光度法, 比色法和X射线光电子能谱(XPS)对离子交换产物的Ti, K元素的原子比和化学价态进行分析, 结果表明, 离子交换产物的经验式为: K_1.34H_0.66Ti₂O₄(OH)₂与H₂Ti₂O₄(OH)₂纳米管相比, 钛酸钾纳米纤维的热稳定性较好, 700℃以上的热处理才使其晶型发生改变, 出现单斜型的K₂Ti₄O₉. 高温处理导致钛酸钾纳米纤维的直径增加, 但仍保持较大长径比. 该材料的BET比表面积为104m²·g^-1.     

锆钛酸铅(PZT)薄膜的自发极化与压电响应

用溶胶－凝胶法在Ｐｔ／Ｔｉ／ＳｉＯ２／Ｓｉ（１００）基片上制备了近等原子比的压电ＰＺＴ薄膜,在准同型相界附近的ＰＺＴ薄膜的应变机制是受极化控制的压电效应,内电场导致薄膜的自发极化定向,使薄膜未经极化就具有明显的压电响应。     

环保型纳米彩色薄膜的性能研究

通过溶胶-凝胶法制备掺杂有不同生物染色剂的SiO2彩色溶胶,将其涂履于普通玻璃表面,制成了均匀透明、色泽丰富的环保型彩色玻璃.研究表明,不同生物染色剂制得的彩色薄膜的性能有所区别,其中蓝色薄膜的实际耐用性(包括耐磨擦、耐腐蚀和抗紫外线功能)最好,达到了室内玻璃制品的性能要求.     

新型工艺制备ZnO薄膜的结构与形貌研究

采用了一种新型工艺制备ZnO薄膜。新工艺采用二步法,首先在N型Si(100)衬底上用离子束沉积溅射一层金属Zn膜,然后通过热氧化金属Zn膜制备ZnO薄膜。通过X射线衍射、原子力显微镜对不同制备工艺下的ZnO薄膜进行结构与形貌的分析比较。研究表明,Zn膜的离子束溅射沉积时间、热氧化时间和辅助枪的离子束对热氧化后的ZnO薄膜再轰击处理对ZnO薄膜的结构与形貌都会产生影响。     

The Influence of Crystal Habit on the Prediction of Dry Powder Inhalation Formulation Performance Using the Cohesive–Adhesive Force Balance Approach

The aim of this investigation was to study the influence of crystalline habit of active pharmaceutical ingredients on the cohesive–adhesive force balance within model dry powder inhaler (DPI) formulations and the corresponding affect on DPI formulation performance. The cohesive–adhesive balance (CAB) approach to colloid probe atomic force microscopy (AFM) was employed to determine the cohesive and adhesive interactions of micronized budesonide particles against the {102} and {002} faces of budesonide single crystals and crystalline substrates of different sugars (cyclodextrin, lactose, trehalose, raffinose, and xylitol), respectively. These data were used to measure the relative level of cohesion and adhesion via CAB and the possible influence on in vitro performance of a carrier-based DPI formulation. Varying the crystal habit of the drug had a significant effect on the cohesive measurement of micronized budesonide probes, with the cohesive values on the {102} faces being approximately twice that on the {002} crystal faces. However, although different CAB values were measured with the sugars with respect to the crystal faces chosen for the cohesive-based measurement, the overall influence on the rank order of the CAB values was not directly influenced. For these data sets, the CAB gradient indicated that a decrease in the dominance of the adhesive forces led to a concomitant increase in fine particle delivery, reaching a plateau as the cohesive forces became dominant. The study suggested that crystal habit of the primary drug crystals influences the cohesive interactions and the resulting force balance measurements of colloid probe CAB analysis.     

In vitro studies on crystallization of SeMHP and strategies for nucleation reduction

Naturally many types of crystals grow in our human body. Especially different crystals or minerals are deposited in human urinary tracts. These crystals are named as octacalcium phosphate (OCP), calcium hydrogen phosphate (CHP), hydroxyapatite (HAP), magnesium hydrogen phosphate (MHP) etc. The SeMg-HPO₄ crystals are also known as Selenio-Newberryite crystals. The main reasons for the formation of crystals are due to the increased concentration of magnesium and phosphate ions in the human urine. In the present study, SeMHP crystals are grown in silica gel medium at various concentrations and different pH values in sun light medium and laser exposed medium. It has been observed that the nucleation rate was partially and completely reduced in sunlight and laser exposed medium, respectively. During the growth period, Liesegang rings were observed. Characteristic studies of SeMHP crystals such as FTIR, AAS, SEM, XRD, TGA/DTA and etching were done. The results are compared with the reported values and discussed in detail.     

离心沉积成膜法在AFM表征纳米粉体中的应用

研究了原子力显微镜在表征纳米粉体微观形貌中的应用,介绍了离心沉积成膜制备纳米粉末待测试样的方法。结果表明,与普通的沉淀成膜法制样相比,离心沉积成膜法以云母片为基底材料,在分散液中加入了凝聚剂,AFM表征结果表明,离心沉积成膜法使纳米粉体的微观形貌在测试中能更好地反映。该方法拓宽了原子力显微镜在表征粉末状样品微观形貌上的应用。     

Direct evidence of lipid rafts by in situ atomic force microscopy

Lipid rafts are membrane microdomains enriched with cholesterol, glycosphingolipids, and proteins. Although they are broadly presumed to play a pivotal role in various cellular functions, there are still fierce debates about the composition, functions, and even existence of lipid rafts. Here high-resolution and time-lapse in situ atomic force microscopy is used to directly confirm the existence of lipid rafts in native erythrocyte membranes. The results indicate some important aspects of lipid rafts: most of the lipid rafts are in the size range of 100-300 nm and have irregular shape; the detergent-resistant membranes consist of cholesterol microdomains and are not likely the same as the lipid rafts; cholesterol contributes significantly to the formation and stability of the protein domains; and Band III is an important protein of lipid rafts in the inner leaflet of erythrocyte membranes, indicating that lipid rafts are exactly the functional domains in plasma membrane. This work provides direct evidence of the presence, size, and main constitutive protein of lipid rafts at a resolution of a few nanometers, which will pave the way for studying their structure and functions in detail.     

Recent trends in surface characterization and chemistry with high-resolution scanning force methods

The current status and future prospects of non-contact atomic force microscopy (nc-AFM) and Kelvin probe force microscopy (KPFM) for studying insulating surfaces and thin insulating films in high resolution are discussed. The rapid development of these techniques and their use in combination with other scanning probe microscopy methods over the last few years has made them increasingly relevant for studying, controlling, and functionalizing the surfaces of many key materials. After introducing the instruments and the basic terminology associated with them, state-of-the-art experimental and theoretical studies of insulating surfaces and thin films are discussed, with specific focus on defects, atomic and molecular adsorbates, doping, and metallic nanoclusters. The latest achievements in atomic site-specific force spectroscopy and the identification of defects by crystal doping, work function, and surface charge imaging are reviewed and recent progress being made in high-resolution imaging in air and liquids is detailed. Finally, some of the key challenges for the future development of the considered fields are identified.