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        검색결과 327

        321.
        1995.03 KCI 등재 서비스 종료(열람 제한)
        The effects of reaction temperature, SO_2 and CO_2 concentration in an air gas stream, particle sizes of limestone on the reactivity and capacity of SO_2 removal have been determined in a thermogravimetric analyser(TGA). The apparent reaction order of sulfation reaction of pre-calcined lime(CaO) with respect to SO_2 is found to be close to unity. The apparent activation energies are found to be 17,000 ㎉/kmol for sulfation of pre-calcined lime and 19,500 ㎉/kmol for direct sulfation of limestone(CaCO_3). The initial sulfation reaction rate of pre-calcined lime increases with increasing temperature, whereas the sulfur capture capacity exhibits a maximum value at 900℃. In direct sulfation of limestone, sulfation reactivity and sulfur capature capacity of sorbent increase with increasing temperature and decreasing CO_2 concentration in a gas bulk stream. The main pore of pre-calcined lime is shifted to the larger pore sizes and pore volume decreases with increasing sulfation time and temperature. The surface area of lime decreases with increasing calcination temperature under an air atmosphere, whereas is rearly constant under a CO_2(5, 10%) atmosphere in a gas stream.
        322.
        1994.12 KCI 등재 서비스 종료(열람 제한)
        A predictive modal is demonstrated for gas removal rates from the atmosphere by dry deposition. Typical deposition velocities are complex functions of surface types, atmospheric stabilities, friction velocities, air pollutants, and so on. In this paper we simulated the calculation of dry deposition velocities near the earth surfaces, simultaneously we estimated real dry deposition velocities using the previous simulation. The measurement taken over a deciduous forest by Padro et al.(1988) were used to verify this model. In the comparison of the value of deposition velocity between numerical computation and observation, there are partially overestimations and underestimations between them, but we can speak that they are in a good accordance.
        323.
        1994.09 KCI 등재 서비스 종료(열람 제한)
        Meteorological parameters in the atmospheric boundary layer and the vertical and horizontal dispersion parameters were determined by analyzing the data obtained by the special upper-air observations of one clear day for each season from October 1991 to August 1992. The concentration of the atmospheric pollutants over Taegu was analyzed by using the application of the Gaussian diffusion model. In the diurnal variation of diffusion of atmospheric pollutants, vertical diffusion due to turbulence is active in daytime while horizontal diffusion due to wind is active in nighttime. The mean concentration of pollutants in the side of downwind is higher during the daytime than the nighttime. Thus, the height of the mixed-layer at the nighttime considered as the most important parameter of the mean concentration of pollutants. In the seasonal variation of diffusion of atmospheric pollutants, vertical diffusion due to strong solar radiation is active in summer case day, and horizontal diffusion due to strong wind is active in winter case day. In winter case day, the mean concentration of pollutants in the side of downwind is maximum in the daytime. However, in summer case day, that is maximum in the nighttime.
        324.
        1994.03 KCI 등재 서비스 종료(열람 제한)
        Dispersion characteristics of air pollutants in the mountainous coastal area are investigated in considering with the mesoscale local circulations using a two dimensional numerical model with two kinds of topograpy of 500m and 300m. In the model, land-sea breezes and mountain-valley wind are mainly considered under the condition of the absence of large scale prevailing flow in the circulation analysis, and the pollutants dispersion is traced by the Lagrangian methods. According to the results, the wind velocity is affected by topography and is stronger in the case of 500m height mountain than that of 300m, the pollutants that source is near the coast transported over the mountain and dispersed to behind inland area. It is classified that the topography change control affects the wind velocity and the circulations. The pollutants that source is different transported and concentrated to behind inland and/or diffused to the sea area by the combination of the wind system with topographic changes. The results can be applied to the air pollution control with the arrangement design of industrial area and the planning of coastal developments.
        326.
        1992.07 KCI 등재 서비스 종료(열람 제한)
        In order to research the adsorption removal characteristics of trace organic by-products in disinfection of drinking water by biological activated carbon(BAC), water samples disinfected with Cl_2, O_3 and ClO_2 after treatment by fluidized-bed system with water added with humic acid(l0㎎/L) were investigated the formation and the removal of trihalomethanes (THMs), and the trace organic by-products by gas chromatography(GC) & gas chromatography/mass selective detector(GC/MSD). Control was used by activated carbon(AC) and water added with hurnic acid(HA). The results were summarized as follow ; The THMs removal effect of BAC by chlorination was in lower 90 % than that of control(HA), the sorts of oxidants formed by Cl_2, O3 and ClO_2 were that O_3 was very fewer than Cl_2 or ClO_2 and that ClO_2 was fewer than Cl_2 The trace organic by-products were esters and phthalates etc. Based on results above, it is concluded that BAC was appeared the more desirable adsorption-degradation removal characteristics than that of AC.
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