• Journal of Korean Society for Atmospheric Environment
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• v.18 no.1
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• pp.1-10
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• 2002

A three-dimensional numerical model which involved the nesting method was developed to reproduce the wind circulation of Kwangyang Bay area which comprises complicated mountains and sea topograph. The calculated results indicated geographical effects of Kwangyang Bay area, sea/land breezes and mount-valley wind which are local circular winds. We also noticed that the northern inland area of Kwangyang Bay formed the very complex wind systems under the influence of such geographic effects when a land breeze was not formed. A good agreement was found between predicted and observed values of temperature. In addition, the calculated results of the wind direction and the wind velocity are in accord with the observed values. They showed only a slight difference in between predicted and the observed values, when the sea breeze and the land breeze are changing.

• Journal of Korean Society for Atmospheric Environment
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• v.1 no.1
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• pp.25-32
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• 1985

To examine the effects of air pollution on Pinus thunbergii growing around Yocheon Industrial Complex, evaluation of visible injury based on Injury Index and chemical analysis of water-soluble sulfur and fluorine contents in needles were carried out on 30 sampling sites. Histological responses of needles were also investigated on the necrotic needle tissues. Not only Injury Index but water-soluble sulfur and fluorine contents were higher at all sites than those at control site, and showed significant correlationship among them. Especially, they were rather higher in the vicinity of air pollutants sources. Water-soluble sulfur contents were positively correlated with average atomospheric $SO_3$ concentrations. Microscopic examination of necrotic needle tissues showed that mesophyll cells were collapsed with hypertrophy and collapse of transfusion cells.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.3
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• pp.173-182
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• 2002

We investigated the effects of operating variables, such as electrical. reactor and gas parameters on toluene removal and discharge property in the dielectric barrier discharge (DBD) process. The toluene removal was initiated with the energy transfer to the reactor by loading of voltages higher than the discharge onset value. The energy transfer and toluene removal increased with the applied voltage. Higher removal rate was observed with smooth surface electrode despite of lower energy transfer compared with the coarse electrode, because more uniform discharge can be obtained on smooth surface state. The decrease of dielectric material thickness enhanced the removal efficiency by increasing the discharge potential. The toluene removal efficiency decreased with the increase of the inlet concentration. The increase of gas retention time enhanced the removal efficiency by the increase of energy density. The oxygen and humidity contents seem to exert significant influences on the toluene removal by dominating the generation of electrons, ions, and radicals which are key factors in the removal mechanism.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.6
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• pp.563-576
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• 1998

To study the influences of the emission sources during lune 13∼15 1997 in Seoul, MESOPVFF II model has been used. The MESOPVFF II model includes terrain effects, chemical transformation and removal processes. Data of 20 surface meteorological stations and the upper air station on mid-west area in Korea were used as a DWM (Diagnostic Wind Model) input data. This model is likely to be applicable because the predicted SO2 concentration was well matched with measured 502 concentration in Seoul and Kyonggido. In generally air pollutants in Seoul have major influence on the other cities but the result of modeling appeared also air pollutants of the other cities influence on Seoul. Finally, in the case of calculating the air quality by diffusion model, the influences of air pollutants emitted in metropolitan area as well as the emission rate in modeling area should be considered.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.2 no.2
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• pp.137-141
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• 1990

When the relative humidity is measured with an aspirated psychrometer, three factors, which affect the measurement of relative humidity, are atmospheric pressure, the size of wet element and the wind velocity. This paper investigated the effects of the above three factors, and the computer code was developed in order to enhance the accuracy of the relative humidity measurement. As results, it is found that the relative humidity decreases by 6%RH with increasing atmospheric pressure from 650 mbar to 1100 mbar. It is found that the relative humidity drops down when the size of the wet element increases, though the effect of the size of the wet element is not significant. Finally, relative humidity increases with the increasing wind velocity. The difference between the psychrometic table in the present KS and the present results is about 2%RH maximum. As a conclusion, the three factors mentioned above should be considered in order to secure accurate measurement of relative humidity.

• Journal of Microbiology
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• v.44 no.4
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• pp.466-471
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• 2006

In this study, we attempted to characterize the biomolecular effects of an atmospheric-pressure cold plasma (APCP) system which utilizes helium/oxygen $(He/O_2)$. APCP using $He/O_2$ generates a low level of UV while generating reactive oxygen radicals which probably serve as the primary factor in sterilization; these reactive oxygen radicals have the advantage of being capable to access the interiors of the structures of microbial cells. The damaging effects of plasma exposure on polypeptides, DNA, and enzyme proteins in the cell were assessed using biochemical methods.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.6
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• pp.633-640
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• 2000

The effects of structure modification of the vortex finder on the collection efficiency and pressure drop have been investigated. The pressure drop in a cyclone having the two stage vortex finder is higher than that in a conventional cyclone and increases proportionally with the increase of square of gas inlet velocity in both cases. The pressure drop of both conventional cyclone of friction resistance at the boundary layer. The collection efficiency of fine dust has been enhanced by addition of vortex finder in a conventional cyclone and gas inlet velocity showing maximum dust removal efficiency increase to 17 m/s(1.7 times of saltation velocity). Optimum size of two stage vortex finder has been induced to 13 cm I.D$\times$2.6cm Length from the results of overall dust collection efficiency. Previous models were tested for the simulation of collection efficiency of cyclone having two stage vortex finder and the Dietz model predict the similar value with experimental results of the present study.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.2
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• pp.121-128
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• 2000

To identify the effects of air pollution on several physiological characteristics of Styrax japonica in Yeochon industrial comples soil properties photosynthetic capacity and chorophyll contents were investigated. All of these measurements were taken on Styrax japonica stand at 1. 3 and 7km from an industrial complex which is an air pollution source. In addition a Styrax japonica stand in Sang-ju city was selected as a control Each physiological measurement was in leaves of east-, west- south- and north-facing branches. The results obtained were as follows: 1) Al contents of soil in Yeochon industrial complex were higher than those of Sang-ju city a non-polluted area. higheral contents contributed to decrease in soil pH. 2) Chlorophyll contents of leaves at 1km from the industrial complex closest from the air pollution source were lower than those of 3 and 7km/ 3) Photosynthetic capacity of Styrax japonica at 1km from the air pollution source was lower than those at 3 and 7km.

• Journal of Electrical Engineering and Technology
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• v.7 no.1
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• pp.97-102
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• 2012

To predict accurately the breakdown voltage in air at atmospheric pressure, a fully coupled finite element analysis combining the hydrodynamic diffusion-drift equations with Poisson's equation is proposed in the current paper. As three kinds of charged transport particles are nonlinearly coupled with spatial electric fields, the equations should be solved by an iterative numerical scheme, in which secondary effects, such as photoemission and photoionization, are considered. The proposed method has been successfully applied to evaluate the breakdown voltage in circular parallel-plane electrodes. Its validity has been proved through the comparison of the predicted and experimental results. The effects of numerical conditions of the initial charge, photoemission, and background ionization on the discharge phenomena are quantitatively assessed through Taguchi's design of experiment method.

• Korean Journal of Microbiology
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• v.16 no.3
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• pp.131-139
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• 1978

Mycoplasma pneumoniae was examined for growth characteristics and morphology when cultivated in several media supplemented with a variety of sera and under different atmospheric conditions. different formula of the medium as well as different sources of lot numbers of the serum in the same medium exhibited varying effects on growth rate and adherence. When the organisms were cultivated in SSR-2 medium in a normal atmospheric environment or under a facultative anaerobic condition provided with carbon dioxide, they developed filamentous cells with heavy growth, whereas mainly round-shaped cells were produced under strict anaerobic conditions of hydrogen and carbon dioxide. Both morphologies of the organism were transformed by switching the incubation environments. An inverted phasecontrast microscopy using modified petri dishes was excellent to observe single cells and useful to follow the development of the cells. Growth, turbidity, and pneumoniae colonies developed on a solid medium and produced clear when overlaid with sheep blood agar.