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71.
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73.
P. GOLDNER 《Molecular physics》2013,111(7):903-908
The accuracy of the Judd-Ofelt theory is investigated in several rare earth doped glasses. Using a normalized method to fit the experimental data, we show that an average accuracy of 5 to 15% is often obtained. However, large errors (up to 35%) can be found on some transitions, even in the case of ions usually considered as well described by the theory. These errors tend also to depend strongly on the materials so that prediction of the accuracy of a calculated intensity is difficult. The Judd-Ofelt parameters found with the normalized method may also differ from those computed in the usual way. Moreover, even in relatively close compositions, quality of the fits can largely vary, weakening possible correlations between compositions and Judd-Ofelt parameters. 相似文献
74.
The competitive adsorption of collagen and bovine serum albumin (BSA) on surfaces with varied wettability was investigated with imaging ellipsometry, and ellipsometry. Silane modified silicon surfaces were used as substrates. The results showed that surface wettability had an important effect on protein competitive adsorption. With the decrease of surface wettability, the adsorption of collagen from the mixture solution of collagen and BSA decreased, while the adsorption of BSA increased. 相似文献
75.
Takashi Sugawara Takehisa Matsuda 《Journal of polymer science. Part A, Polymer chemistry》1997,35(1):137-142
A novel supramolecularly assembled surface architectural method was developed, which involved a self-assembling process of amphiphilic molecules and a subsequent photochemical process. The specially designed molecules were cascade “tree” molecules composed of a phenylazido group as root, an aliphatic hydrocarbon chain as stem, and two or three tris(hydroxymethyl)aminomethane groups as leaves. Using a horizontal lifting method, unimolecular assemblies which formed at an air/water interface were transferred to polyethylene (PE) surfaces. Upon ultraviolet irradiation, these molecules were covalently fixed on the surfaces due to the photochemical reactivity of the phenylazido group. Treated surfaces became wettable with water, indicating that hydrophilic hemispheres were located at the outer surface region of the PE surfaces. Bimolecular assemblies composed of cascade molecules and noncascade molecules with a hydroxyl group at a terminus exhibited lower advancing and receding contact angles and reduced hysteresis than those of unimolecular ones, indicating that these bimolecular assemblies have a well-structured molecular organization with a high degree of packing. © 1997 John Wiley & Sons, Inc. 相似文献
76.
Tyrosine-derived polycarbonates having carboxylic acid pendant groups were characterized by water contact angle and X-ray photoelectron spectroscopy (XPS). A pronounce decrease of receding angle as well as contact angle hysteresis as a function of acid composition strongly indicated that the acid groups are more accessible at the water/polymer interface after hydration. pH dependent contact angle confirmed an existence of carboxylic acid groups in the surface region. The receding angle transition appearing in the pH range of 4-6 was a consequence of hydrophilicity change due to interconverting from carboxylic acid (-COOH) to carboxylate ion (-COO−). The surface compositions of imidazole-labeled polymers as analyzed by XPS were consistent with the bulk stoichiometry of the polymers. Reactivity of acid groups towards chemical reaction at the surface was also investigated. The acid groups at the surface of polymers were capable of adsorbing a significant amount of calcium ion from simulated body fluid and being activated by a reaction with N-hydroxysuccinimide. 相似文献
77.
利用Washburn方程测量固体粉末的润湿性,研究了十二烷基苯磺酸钠(SDBS)水溶液在硅胶及高岭土两种固体粉末表面上的接触角,用荧光猝灭法测定了SDBS在水溶液里的胶束平均聚集数。并由此探讨了十二烷基苯磺酸钠水溶液在固体粉末表面的润湿性,表面活性剂的临界胶束浓度(CMC)与表面含油粉末脱油率的关系。 相似文献
78.
Masayoshi Satoh Kumi Shirai Hiroshi Saitoh Takeshi Yamauchi Norio Tsubokawa 《Journal of polymer science. Part A, Polymer chemistry》2005,43(3):600-606
The photograft polymerization of various vinyl monomers onto nanosized silica surfaces was investigated. It was initiated by eosin moieties introduced onto the silica surface. The preparation of the silica with eosin moieties was achieved by the reaction of eosin with benzyl chloride groups on the silica surface.These were introduced by the reaction of surface silanol groups with 4‐(chloromethyl)phenyltrimethoxysilane in the presence of t‐butyl ammonium bromide as a phase‐transfer catalyst. The photopolymerization of various vinyl monomers, such as styrene, acrylamide, acrylic acid, and acrylonitrile was successfully initiated by eosin moieties on the silica surface in the presence of ascorbic acid as a reducing agent and by oxygen. The corresponding polymers were grafted from the silica surface. The grafting efficiency (percentage of grafted polymer to total polymer formed) in the photoinitiation system was much larger than that in the radical polymerization initiated by surface radicals; these radicals were formed by the thermal decomposition of azo groups introduced onto the silica surface. It was found that the polymer‐grafted silica gave stable dispersions in good solvents of grafted polymer and the wettability of the surfaces can be easily controlled by grafting of polymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 600–606, 2005 相似文献
79.
80.
Xin Zhao Yuxia Gao Chenhui Zhang Yanqiu Zhu Jinmei Lei Yue Ma 《Journal of Dispersion Science and Technology》2013,34(12):1820-1828
AbstractDue to the important use of pesticide formulation, it is necessary to make it clear how ionic surfactant effect the wettability at leaf surface. In this work, we used the sessile drop method to study the wettability of SDS and DTAB on wheat leaf surfaces at different leaf stages, and reveal the relationship between surfactants structures and leaf stages of wheat leaf surfaces on wettability behavior. Results showed that few surfactant molecules adsorbed at the interface at low concentrations. With the concentration increased, the surfactant replaced the air layer partially within the nano/micro structure of leaf surfaces. When the concentration exceeded to CMC, the adsorption of surfactant molecules was saturated at both air-liquid interface and solid-liquid interface, the wetting state was still the transitional state between Cassie-Baxter’s and Wenzel’s state. In all concentrations, the adhesional tension and surface tension showed the linear relationship and the slope values were all below ?1, suggesting there were more surfactant molecules adsorbed at the solid-liquid interface than the liquid-air interface. As SDS is a common wetting agent and DTAB is a common fungicide in agrochemical, this study will provide potential guidance in practical application of pesticide solutions in leaf surface wetting. 相似文献