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991.
The total energies of intermetallic compounds in the Sn–Ti system are calculated employing electronic density-functional theory (DFT) using pseudopotentials constructed by the projector augmented waves (PAW) method in the generalized gradient (GGA) approximation for the exchange and correlation energy. The calculations are performed for the experimentally observed compounds at their ideal stoichiometry as well as for structures which are stable in systems of early transition metals or rare earth elements with p-elements of columns IIIB, IVB, and VB. The calculated formation enthalpy of the hexagonal Sn5Ti6 compound is slightly less exothermic than the value obtained by direct reaction calorimetry. For the stable intermetallic compounds, the calculated zero-temperature lattice parameters agree well with those obtained experimentally at ambient temperature. More, for stable phases with unit cell-internal degree(s) of freedom, the results of ab initio calculations show good agreement when compared with data obtained by structural analysis of X-ray diffraction. The composition dependence of the enthalpies of formation is slightly asymmetric. The electronic densities of state of the D88- Sn3Ti5 compound have been computed; the curve shows the hybridization of Sn 5p states with Ti 3d states. The stability of the intermetallic compounds in the Ti–Sn system is due to this hybridization. 相似文献
992.
Black iron-chromium (Fe-Cr) bearing oxide pigments are generally utilised as effective colourants in a wide variety of applications. However, in the case of their use within ZnO-containing glazes, they yield an undesirable brown colour instead of expected black colour. In order to understand the colour change in this system, we report the use of focused ion beam (FIB) sample preparation technique followed by the use of analytical transmission electron microscopy (TEM) characterisation techniques. According to the results, the formation of a reaction layer between the pigment and glaze was identified with an average composition of Zn0.48Fe0.79Cr1.32O4. Additionally, the valance of Fe was determined as 3+ in the pigment grain, whereas 2+ in the reaction layer and the glaze, respectively. Therefore, it was concluded that the colour change is occurring as result of the valence variation of Fe, the formation of Zn0.48Fe0.79Cr1.32O4 compound and the outward diffusion of Fe into the glaze. 相似文献
993.
Free radical/cationic hybrid photopolymerization of acrylates and epoxides was induced using an initiator system comprised of the dye derivative 5,12-dihydroquinoxalino[2,3-b]quinoxaline or 5,12-dihydroquinoxalino[2,3-b]pyridopyrazine as the sensitizers and hexafluoroantimonate triarylsulfonium salt as the initiators. The curing experiments were carried out in the presence of air and the consumption of each monomer upon VIS-radiation was monitored in situ by real-time infrared spectroscopy. Hardness (H), elastic modulus (E) and the H/E ratio of the coatings obtained by visible-initiated acrylate/epoxide hybrid photopolymerization were determined using nanoindentation. DSC measurements show that the initiator system presented here may produce an interpenetrating polymer network. The pencil hardness of the obtained coatings indicates that the dye/hexafluoroantimonate triarylsulfonium salts systems studied here may have practical applications as visible-light hybrid initiators. 相似文献
994.
In the present study, varying amounts of tetramethylguanidinium moiety have been conjugated to linear polyethylenimine to obtain linear polyethylenimine-tmg (LPTG) polymers. Incorporation of hydrophobic and highly basic moiety in the polymeric backbone resulted in the significant improvement in the antibacterial activity which was confirmed by zone of inhibition and MIC assays. Further, the results of transmission electron microscopy and confocal studies revealed that the projected LPTG polymers possessed higher antibacterial activity than the native polymer. In addition, these modified polyethylenimine (PEI) polymers were capable of reducing auric chloride into stable gold nanoparticles. These polyamine-stabilized gold nanoparticles can be used in various biomedical applications. 相似文献
995.
Charge Transport: Nonfullerene Electron Transporting Material Based on Naphthalene Diimide Small Molecule for Highly Stable Perovskite Solar Cells with Efficiency Exceeding 20% (Adv. Funct. Mater. 20/2018) 下载免费PDF全文
996.
997.
《国际聚合物材料杂志》2012,61(7):557-574
ABSTRACT The present work investigates the effect of various filling levels (FLs) of FeCl3 on the structure and physical properties of polystyrene (PS) films. X-ray diffraction scans revealed two main peaks, the amorphous and the polymerization peaks. The infrared transmission spectra depicted the main PS characterizing peaks. The direct current (dc) electrical conduction was attributed to the interpolaron charge carrier hopping. The temperature dependence of dc magnetic susceptibility exhibited Curie–Weiss behavior. The positive values of the paramagnetic Curie temperature (θp) indicate the predominance of a ferromagnetic exchange interaction between the magnetic centers at low temperatures, whereas the negative value of θp at 9% FL suggests the existence of an antiferromagnetic exchange interaction. The electron spin resonance (ESR) investigations imply the presence of isolated and aggregated Fe+3 ions at intermediate and higher FLs, respectively, in the polymeric matrix. 相似文献
998.
对BCI内外墙保温装饰板材料的诸多特点进行了分析,介绍了该保温装饰板的施工方法及程序,列举了BCI内外墙保温装饰板的产品系列及应用范围,以期进一步推广该保温装饰板的应用。 相似文献
999.
Transition Metal Oxides: Electron‐Beam‐Induced Perovskite–Brownmillerite–Perovskite Structural Phase Transitions in Epitaxial La2/3Sr1/3MnO3 Films (Adv. Mater. 18/2014) 下载免费PDF全文
1000.