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81.
82.
A.G. Dobrikova M.I. Dimitrov S.G. Taneva I.B. Petkanchin 《Colloids and surfaces. B, Biointerfaces》2007,56(1-2):114-Optics
Using microelectrophoresis and electric light scattering techniques, we investigated the adsorption characteristics, surface coverage and surface electric parameters of superstructures from two isoforms of plastocyanin, PCa and PCb, in an oxidized state adsorbed on β-ferric hydrous oxide particles. The surface electric charge and electric dipole moments of the composite particles and the thickness of the protein adsorption layer are determined in a wide pH range, at different ionic strengths and concentration ratios of PC to β-FeOOH. The adsorption of the two proteins was found to shift the particles’ isoelectric point and to alter the total electric charge and the electric dipole moments of the oxide particles to different extent. A “reversal” in the direction of the permanent dipole moment is observed at lower pH for PCb- than for PCa-coated oxide particles. Strict correlation is found between the changes in the electrokinetic charge of the composite particles and the variation in their “permanent” dipole moments. Data suggest that the adsorption of the proteins is driven by electrostatic and/or hydrophobic interactions with the oxide surfaces dependent on pH. The adsorption behaviour is consistent with the involvement of the “eastern” and “northern” patches of the plastocyanin molecules in their adsorption on the oxide surfaces that are differently charged depending on pH. 相似文献
83.
S. M. A. Shibli V. S. Dilimon V. S. Saji 《Journal of Solid State Electrochemistry》2007,11(2):201-208
It has been recently proved that RuO2 can act as an effective surface activator of aluminum alloy sacrificial anodes. TiO2 has the property of stabilizing RuO2 coating and resisting biofouling on metal surfaces. Hence, a mixed oxide catalytic coating of TiO2 and RuO2 can enhance the galvanic performance of aluminum alloy sacrificial anodes and resists biofouling on the anode surface. In the present work RuO2–TiO2 mixed oxide was coated on aluminum alloy sacrificial anodes. The large and uniform porous nature of the coating was found to facilitate efficient ion diffusion. The coating was found to persist on the anode even after 3 months of galvanic exposure. The anode having an optimum combination of the mixed oxide had 70% TiO2 as the major component in the coating. The catalytic coating significantly improved the performance of the anodes to a large extent. 相似文献
84.
泡沫铅对VRLA电池负极活性物质结构及性能影响 总被引:3,自引:0,他引:3
0引言随着36V/42V汽车电源系统的提出,新一轮汽车用电池的竞争不断加剧。从目前情况看,铅酸电池由于具有成本低廉,使用可靠,原材料来源丰富,铅回收率可高达98%等优点,因此成为电动车电源最实际的选择之一[1]。但作为电动车用电池,需要克服其比能量低、充电接受能力差和负极硫酸盐化等缺点。为此各国科学家开展了大量的研究工作。最近报道用铸造多孔体作为敞口铅酸电池的集流体,它的比表面积为14cm2·cm-3,正极活性物质利用率上升到50%,远高于传统的铸造板栅[2]。在铅酸电池集流体研究领域里另一个重大进步,就是以R V C(R etic-ulated V i… 相似文献
85.
光学活性化合物的工业合成 总被引:9,自引:0,他引:9
本文介绍了光学活性化合物研究现状及发展趋势。并从技术和经济角度论述了工业合成光学活性化合物的可能性 相似文献
87.
V. Riveros M. Gulppi M. Páez J. H. Zagal C. M. Rangel D. Huerta P. Skeldon G. E. Thompson 《Journal of Solid State Electrochemistry》2006,10(2):83-90
Using voltage-time responses and cyclic voltammetry, the initial stages of anodizing of Al–2.1 at.% Ag and Al–4 at.% Ag alloys
are shown to depend upon the heat treatment of the alloys and the pre-treatment of the alloy surfaces. Chemical polishing
of solution-treated alloys leads to relatively uniform anodic oxidation on a relatively smooth alloy surface, in the absence
of significant effects of coarse, silver-rich intermetallics. In contrast, losses of current to oxygen generation arise for
the roughened alloy surface from mechanical polishing. With ageing, secondary reactions at the relatively silver-rich intermetallics
are more prevalent, although the effects on the voltage-time response depend upon the balance between processes occurring
on the matrix and intermetallic regions, including film growth, oxygen generation within the anodic film, film damage due
to release of oxygen, dissolution of silver species and re-growth of damaged film. 相似文献
88.
89.
This paper describes basic studies of the surface modification of polyimide covered wires for insulation of electrical machines. Drain-off of the impregnating resin during production should be reduced by introduction of surface catalytic groups. 1H NMR kinetic analysis of aminolytic ring opening reaction of low molecular model compounds for polyimides showed very fast modification reactions. The catalytic effect of various functional groups on unsaturated polyester imide, acrylate and epoxy resins was investigated by DSC. Co(II)-catalysts and tertiary aliphatic amines proved highest activity for double bond containing systems and epoxy resins, respectively. Aminolytic treatment of Kapton® slides was followed by ATR-IR spectroscopy. Plate-plate rheometer measurements of epoxy resins employing tertiary amine-treated Kapton® slides proved significantly reduced gelling temperature. 相似文献
90.
The micellization behavior of an anionic gemini surfactant, GA with nonionic surfactants C12E8 and C12E5 in presence of 0.1 M NaCl at 298 K temperature, has been studied tensiometrically in pure and mixed states, and the related
physicochemical parameters (cmc, γ
cmc, pC
20, Γ
max, and A
min) have been evaluated. Tensiometric profile (γ vs log [surfactant]), for conventional surfactants, generally consists of a single point of intersection; a gradually decreasing
line (normally linear, or with slight curvature) ultimately saturates in γ at a particular [surfactant], corresponding to complete monolayer saturation. The gemini, in this report, led to two unequivocal
breaks in the tensiometric isotherm. An attempt to the interpretation of the two breaks from molecular point of view is provided,
depending solely on the chemical structure of the surfactant. The gemini, even in mixed state with the conventional nonionic
surfactants C12E5 and C12E8, manifested the dual breaks; of course, the dominance of the feature decreases with increasing mole fraction of the nonionics
in the mixture. Theories of Clint, Rosen, Rubingh, Motomura, Georgiev, Maeda, and Nagarajan have been used to determine the
interaction between surfactants at the interface and micellar state of aggregation, the composition of the aggregates, the
theoretical cmc in pure and mixed states, and the structural parameters according to Tanford and Israelachvili. Several thermodynamic
parameters have also been predicted from those theories. 相似文献