Preparation and photochromism of nanocomposite thin film based on polyoxometalate and polyethyleneglycol

A photochromic nanocomposite based on Keggin structure phosphomolybdic acid (PMoA) well dispersed in polyethyleneglycol (PEG) was fabricated. TEM image showed that PMoA nanoparticles with narrow size distribution were finely dispersed in polymer matrix. FT-IR results showed that the Keggin geometry of polyoxometalates was still preserved inside the composites and strong coulombic interaction was built between PMoA and polymer matrix. Under UV irradiation, the film was reduced photochemically to yield a blue species, which was in accordance with a charge-transfer mechanism.     

交联透明质酸的降解及其释药性能

用己二酸二酰肼（ADH）对透明质酸（HA）进行化学修饰，制备交联透明质酸（HA-ADH）薄膜。粘度法测试表明HA-ADH是一种可降解的生物材料，并且与HA相比，HA．ADH的降解速率减慢。在此基础上，研究了以疏水性的替硝唑（TDZ）和亲水性的头孢唑啉钠（CEZ）为模拟药物的HA-ADH药物载体薄膜的释药性能。紫外-可见（UV-Vis）吸收光谱检测表明，HA-ADH是一种疏水性药物TDZ的优良缓释制荆，这是由于TDZ的疏水性和HA-ADH薄膜的缓慢溶胀和降解性能的结合而得到的，药物的释放主要受扩散机制控制。     

Wave dynamics on a thin-liquid film falling down a heated wall

The dynamics of a thin liquid film falling down a uniformly heated wall is studied. The model introduced by Kalliadasis et al. [J. Fluid Mech. 475 (2003) 377] for the same problem is revisited and its deficiencies, namely the prediction of a critical Reynolds number with 20% error, cured. For the energy equation a high-order Galerkin projection in terms of polynomial test functions is developed. It is shown that not only does this more refined formulation correct the critical Reynolds number, but it also gives, with an appropriate expansion close to criticality, the long-wave theory. Bifurcation diagrams for permanent solitary waves are constructed and compared with the solution branches obtained from different models. It is shown that, in all cases, the long-wave theory exhibits limit points and branch multiplicity, while the other models predict the continuing existence of solitary waves. Time-dependent computations show that the free surface and interfacial temperature approach a train of coherent structures that resemble the infinite-domain stationary solitary pulses.     

Optical switching properties of RCo2-type alloy thin films by electrochemical hydrogenation

The switchable optical properties of Pd-protected RCo₂-type Ho_0.6Mm_0.4Co₂ alloy thin films have been investigated in a KOH electrolyte. The reversible optical switching has been carried out simultaneously by measuring transmitted light through the thin film during electrochemical charging–discharging of hydrogen. The dependence of switching speed and cyclic durability of the film on the charging and discharging current density as well as concentration of KOH electrolyte has been studied. In addition, cyclic voltammetric measurements have been performed to examine the hydride formation and decomposition reactions.     

用于PET薄膜回收的螺杆设计

根据PET薄膜的特点和高分子熔融态流动理论，分析了挤出回收用螺杆的各段结构，及螺杆参数选择，设计出大长径比、深槽、双排气、高效专用螺杆。     

Breakdown of oil films and formation of residual films

The breakdown processes of oil films under quasi-static loading have been investigated by using a newly developed steel-oil-mercury system. The relationship between the thickness and breakdown ratio of a hexadecane film is represented by a single master curve independently of the indentation speed, indentation load, and temperature. The master curve shows that the breakdown process of hexadecane includes two stages; one is the decrement of the thickness without breakdown and the other is the decrement of the thickness with a drastic progress of breakdown. By solving a small amount of fatty acid in hexadecane, the thickness increases and the breakdown ratio decreases noticeably; a multilayer residual film supporting normal load is formed between two metal surfaces. Experiments at different temperatures reveal a negative relationship between the temperature and thickness of residual film, which indicates that the residual film is organized by physical interaction rather than chemical interaction. At least under a lower concentration, the residual film appears to consist of not only fatty acid molecules but also hexadecane molecules.     

基于光敏自组装多层膜的液晶光控取向膜

采用layer-by-layer(LBL)的方法，将基板依次在具有光敏双键的季铵盐水溶液和聚乙烯基苯磺酸钠水溶液中浸泡，石英基板表面形成了自组装多层沉积膜。经线性偏振紫外光辐照后，LBL多层膜表现出明显的紫外吸收各向异性。将两片带有各向异性薄膜的基板做成平行液晶器件。在正交的偏光显微镜下观察，发现取得均一、稳定的取向效果。该种光控取向膜有望用作LCoS微显示的取向层。     

Evolution of grain structure in thin film reactions

In this paper, we examine, both experimentally and theoretically, the kinetics of formation and microstructure of product phases in thin film reactions, using the Nb/Al and Ti/Al systems as our prototypes. The results of calorimetry and microscopy studies are interpreted using simple kinetic and morphology models. In particular, the kinetic models employed here focus on the nucleation and growth components of the phase formation process and the morphology models provide a starting point for the classification of product grain structures. An erratum to this article is available at .     

溅射——气体——聚集共沉积法制备金属／金属（介质）复合团簇镶嵌薄膜

提出了溅射－气体－聚集共沉积制备金属／金属（介质）复合团簇镶嵌薄膜的新方法，并利用该方法成功地在方华膜衬底上制备了系列Ｆｅ／Ａｇ及ＣａＦ２复合团簇镶嵌薄膜样品。透射电镜分析结果表明，样品中Ｆｅ（Ｃｕ）团簇都较好地镶嵌于Ａｇ（ＣａＦ２）基质中，其结构为两种材料的多晶共存形态。进一步分析发现，与块材相比，Ｆｅ／Ａｇ样品中Ｆｅ团簇晶格常数呈现出不同程度的收缩，而Ｃｕ／ＣａＦ２样品中Ｃｕ团簇晶格常数则呈现出不同程度的膨胀。运用附加压力的模型对该现象进行了解释。     

氧化铝/锌合金复合材料界面的SEM观察

利用挤压铸造制备氧化铝／锌合金复合材料，在扫描电镜（ＳＥＭ）上观察复合材料的界面。结果表明，在复合材料中纤维与基体间存在致密界面层，合金元素通过适当的化学反应可改善纤维与基体间的结合；在凝固过程中，纤维／基体界面上的硅在共晶体的共生生长过程中起了领先相作用，导致复合材料的共晶转变是由铝硅共晶转变和锌铝共晶转变两者组成。