Hybrids of colloidal silica and waterborne polyurethane

Waterborne polyurethane (WPU) was synthesized and followed by adding colloidal silica to prepare WPU-silica hybrids. The silica content in the hybrid thin films was varied from 0 to 50 wt%. The experimental results revealed that the viscosity of these hybrid solutions increased with increasing silica content and resulted in the aggregation of silica particle in the hybrid films. The latter result was evidenced by SEM examination. The effect of interaction between silica particle and urethane polymer chains is more significant with increasing silica content. The prepared hybrid films show much better thermal stability and mechanical properties than pure WPU. The optical transparence did not linearly decrease with increasing the silica fraction in the hybrid thin film. At below 20% silica content, the film transparence decreased with increasing silica content; the converse is true at above 20% silica content. These results showed that the prepared hybrid films demonstrated tunable transparence with the silica fraction in the films.     

CH...pi interaction for rhenium-based rectangles: an interaction that is rarely designed into a host-guest pair

Alkoxy- and thiolato-bridged Re(I) molecular rectangles [{(CO)3Re(mu-ER)2Re(CO)3}2(mu-bpy)2] (ER = SC4H9, 1a; SC8H17, 1b; OC4H9, 2a; OC12H25, 2b; bpy = 4,4'-bipyridine) exhibit strong interactions with several planar aromatic molecules. The nature of their binding was studied by spectral techniques and verified by X-ray diffraction analysis. Standard absorption and fluorescence titrations showed that a relatively strong 1:1 interaction occurs between aromatic guests such as pyrene and these rectangles. The results of a single-crystal X-ray diffraction analysis show that the recognition of 1 with a pyrene molecule is mainly due to CH...pi interactions and the face of the guest pyrene is located over the edges of the bpy linkers of 1. This is a fairly novel example of an interaction that is rarely designed into a host-guest pair. Furthermore, the interaction of 1 with Ag+ results in the self-organization of supramolecular arrays, as revealed by solid-state data.     

New barium cobaltite series Ba(n+1)Co(n)O(3n+3)(Co8O8): intergrowth structure containing perovskite and CdI2-type layers

Single crystals of two new cobaltites, Ba2Co9O14 and Ba3Co10O17, were obtained from the flux of K2CO3 in the temperature range 800-890 degrees C. They crystallize in an intergrowth structure containing perovskite block and CdI2-type layers and can be attributed to the n = 1 and 2 members in a new intergrowth series of cobaltites, Ba(n+1)Co(n)O(3n+3)(Co8O8). Both Ba2Co9O14 and Ba3Co10O17 are metastable and transform into the known 2H-perovskite-related oxides at high temperature.     

Separation of phospholipids by capillary zone electrophoresis with indirect ultraviolet detection

A simple method for separation of different anionic and zwitterionic phospholipid classes by capillary zone electrophoresis (CZE), using indirect UV detection with adenosine monophosphate (AMP) as background electrolyte and the UV-absorbing additive, was successfully developed in this study. The separation conditions including apparent pH (pH*) of running buffer, concentration of AMP, organic solvent, applied voltage and capillary temperature were systematically optimized. The application of this method to human blood sample was also briefly examined.     

Theoretical study on photophysical and charge transport properties of 1,6-bis(2-hydroxyphenol)pyridylboron bis(4-n-butylphenyl)phenyleneamine compound

The absorption and emission spectra of 1,6-bis(2-hydroxyphenol)pyridylboron bis(4-n-butylphenyl)phenyleneamine were systematically calculated by time-dependent density functional theory (TD-DFT) level. These results are in good agreement with experiment ones. The charge transport properties were investigated within the framework of the charge hopping model. The results show that 1,6-bis(2-hydroxyphenyl)pyridineboron ((dppy)BF) functions as a electron transport group and triphenylamine as a hole transport group; the charge transport ability for the two types of carriers is not only high but also nearly balanced, which explains why it is an efficient single-layer electroluminescent device. On the basis of the large second-order polarizability value and high transparency, this compound has the possibility to be an excellent second-order nonlinear optical material. The main origin of this large second-order nonlinear optical response is charge transfer from the triphenylamine group to (dppy)BF.     

Discrimination of basal cell carcinoma from normal dermal stroma by quantitative multiphoton imaging

We performed multiphoton fluorescence (MF) and second-harmonic generation (SHG) imaging on human basal cell carcinoma samples. In the dermis, basal cell carcinomas can be identified by masses of autofluorescent cells with relatively large nuclei and marked peripheral palisading. In the normal dermis, SHG from dermal collagen contributes largely to the multiphoton signal. However, within the cancer stroma, SHG signals diminish and are replaced by autofluorescent signals, indicating that normal collagen structures responsible for SHG have been altered. To better delineate the cancer cells and cancer stroma from the normal dermis, a quantitative MF to SHG index is developed. We demonstrate that this index can be used to differentiate cancer cells and adjacent cancer stroma from the normal dermis. Our work shows that MF and SHG imaging can be an alternative for Mohs' surgery in the real-time guidance of the secure removal of basal cell carcinoma.     

小分子铱配合物及其电致发光

由于磷光金属配合物可以同时利用单线态和三线态激子发光,使有机电致发光器件的理论内量子效率达到100%,突破了25%的极限。因而以磷光金属配合物为发光材料制成的器件备受关注。在这些金属配合物中,铱配合物由于具有较强的发光特性、发光波长可调性、较好的热稳定性和电化学稳定性以及能够形成便于蒸镀的中性分子,而成为最有应用潜力的电致磷光材料。本文综述了近几年铱配合物磷光材料在分子设计与合成方法、发光机理及器件构筑等方面的研究进展。特别介绍与讨论了磷光铱配合物的两种发光机理,即基于同配体铱配合物或异配体铱配合物的主配体到中心金属离子的电荷转移三线态(³MLCT)发射和基于异配体铱配合物的辅助配体三线态(³LC)发射。根据反应条件的差异,归纳总结了合成铱配合物常用的4种方法以及合成fac式和mer式的铱配合物的方法。还根据材料的发光颜色及其电致发光的不同,对磷光铱配合物材料进行了分类与讨论。此外,简要介绍了用于器件制作的主体材料。最后,展望了金属有机配合物电致磷光材料的发展前景,并提出了今后磷光材料的发展方向。     

Material transport in dip-pen nanolithography

Dip-pen na.nolithography （DPN） is a useful method for directly printing materials on surfaces with sub-50nm resolution. Because it, involves the physical transport of materials from a scanning probe tip to a surface and the subsequent chemical interaction of that material with the surface, there are many factors to consider when attempting to understand DPN. In this review, we overview the physical and chemical processes that are known to play a role in DPN, Through a detailed review of the literature, we classify inks into three general categories based on their transport properties, and highlight the myriad ways that. DPN can be used to perform chemistry at the tip of a scanning probe.     

Approximations and cotorsion pairs related to a tilting pair

The notion of a tilting pair Miyashita in 2001. It is a useful tool in cotorsion pairs related to a fixed tilting （covariantly） finite subcategory and a tilting pair were given in this paper. over artin algebras was introduced by the tilting theory. Approximations and pair were discussed. A eontravariantly eotorsion pair associated with a fixed