Formation Of Compact Film Research Articles

Adsorption of s-triazine pesticides, terbutylazine and atrazine: environmental risk parallels differences in compact film formation

Adsorption of terbutylazine and atrazine on a mercury electrode was investigated by means of time resolved capacitance measurements and phase-sensitive a.c. polarography. Both compounds form compact adsorbed layers. The temperature dependence of the capacitance yields a critical transition temperature of the compact film formation, which is higher for atrazine. Differences in condensation kinetics of both pesticides are correlated with their environmental contamination behavior.

Lithium insertion into self-organized mesoscopic TiO 2 (anatase) electrodes

Self-organized nanocrystalline anatase films were prepared by a sol–gel technique with subsequent hydrothermal growth of crystals in basic solutions. Hydrothermal treatment at 190–230°C leads to the formation of compact films with narrow pore size distribution. Materials prepared at higher temperatures show more open structure with lower specific surface area. The electrochemical activity of the self-organized electrodes decreases with decreasing specific surface area. Ordered electrodes showed higher insertion capacity by ca. 15% compared to those of non-ordered electrodes with the same specific surface area. Insertion coefficients, x, exceeding 0.5 were observed for very thin (0.2 mg/cm 2) self-organized films with specific surface area higher than 60 m 2/g. However, these values were not reproduced for thicker films. The insertion rate depends on the inserted charge with a maximum at x∼0.1. It indicates that only a part of the total electrode–electrolyte interface is available for charge transfer reaction. The total insertion capacity is therefore affected by propagation of the electrochemically active surface within the film.

A Heterogeneous Model of Combustion of Porous Media

Abstract This paper is devoted to the theoretical investigation of combustion of porous media. For the first time the process of flame spread in a layer of a solid porous material with an external supply of a gaseous oxidizer has been analyzed in terms of a heterogeneous model. The multi-stage character of the process (filtration, sorption, chemical reaction) is taken into account. In many practically important cases (e.g., in the case of combustion of coarsely divided particles with the formation of compact films of a condensed product) the sorption stage plays the dominant role in the mechanism of thermal flame spread. This role is developed from a detailed analysis of heat and mass transfer in the model structure of a heterogeneous medium. Such an approach makes it possible to determine explicitly the dependence or the rate of combustion on both the filtration and sorption and structural characteristics of the solid phase (the solubility of gas in the solid phase, the diffusion activation energy, the sizes of pores and particles, etc.).

鉄鋼の腐食抑制に関する研究 (第2報)

Corrosion rate of mild steel in phosphoric acid or sulfuric acid were studied using one kind or a mixture of 2 or 3 kinds of nitrogen or sulphur containing organic inhibitors.The results indicate as follows:(1) Inhibiting efficiency of the mixture is excellent compared with the case in which one kind of inhibitor is used.(2) Some inhibitors react as corrosion stimulator when singly used in different kinds of acid, but when they are mixed with one or two other inhibitors they behave as excellent inhibitors.The cause of these phenomena is considered as the formation of compact films of inhibitor molecules, which are polarized by the effect of electric field and great dielectric constant in solution. Such adsorption film becomes compact, when 2 or 3 kinds of inhibitor molecules are adsorbed.