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        검색결과 2,366

        2226.
        1999.08 KCI 등재 서비스 종료(열람 제한)
        We will calculate concentration of air pollutants using ISCST3, FDM and AERMOD of models recommended in U. S. EPA which are able to predict concentration of short term for point source, complex like industrial complex, power plant and burn-up institution. Before executing model, as analyzing computational result of many cases according to selecting of input data, we will increasing predictable ability of model in limit range of model. Especially, we analyzed three cases - case of considering various emission rate according to time scale and not, case considering effect of atmospheric pollution materials removed by physical process. In our study, after comparing and analyzing results of three model, we choose the atmospheric dispersion model reflected well the characteristic of the area. And we will investigate how large the complex pollutant sources such as industrial complex contribute to atmospheric environment and air quality of the surrounding the area as predicting and estimating chosen model.
        2227.
        1999.08 KCI 등재 서비스 종료(열람 제한)
        This paper describes the working of algal culture system under batch and continuous feeding effluents in biological treatment process. The main objective of this study was the determination of fundamental operating parameters such as dilution rates, light intensity, biomass concentration, nutrients contents, which engender an effective nutrient and organic waste removal process. The results of this research indicate that the algae system will remove effectively nutrient and organic waste. In batch cultures, 91.8% dissolved orthophosphate and 83.3% ammonia nitrogen were removed from the sewage in ten days. In continuous flow systems, a detention time of 2.5 days was found adequate to remove 91% T-P, 87% T-N and 95% NH3-N. At 22-28℃, 60 rpm, with an intensity of 3500 Lux, the specific growth rate, k was 0.59/day in batch experiments. The optimal growth temperature and nutrients rate (N/P) were respectively 25℃ and 3∼5. With an abundant supply of nutrients, it was possible to sustain substantial population densities in the temperature range of 22∼28℃.
        2229.
        1999.06 KCI 등재 서비스 종료(열람 제한)
        Fritillaria pallidiflora의 전분체 미세구조와 신구인경의 세포간 대사물질의 이동을 전자현미경으로 관찰하였다. 기존의 인경과 새로 형성된 인경세포내 전분체는 내부 막구조에 있어서 뚜렷한 차이를 나타내었을 뿐만 아니라 대사물질의 세포간 이동도 활발히 이루어지고 있음을 관찰할 수 있었다. 엔도사이토시스와 엑소사이토시스 현상이 세포막에서 관찰되었으며 대사물질의 세포간 이동을 위해 원형질 연락에 있어서 염류수송 경로가 형성됨을 알 수 있었다. 또한 일단의 소포체들이 원형질 연락의 말단에 위치하고 있었는데 이는 세포간 물질 이동에 이들이 관여하고 있음을 알 수 있었다. 이러한 결과는 F. pallidiflora의 신구 인경형성과 발달에 미치는 기작을 연구하는데 유용하게 이용될 수 있는 것으로 생각된다.
        2230.
        1999.04 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study is providing basic data to control the air pollutants from solid waste incinerator. Incinerating the waste wood, the electrostatic precipitator had the best collection efficiency. The leather incineration had the same collection efficiency as synthetic resin incineration. And the coarse particle collection efficiency was high. As you know in correlation of leather incineration, pollutants produced a from incinerator are mostly fine particles. If the scrubber used only in the process produced a lot of fine particles. It is adequate to use the above control devices, together with high efficiency collector like bag-filter. To select the adequate control devices, it is required to investigate the size distribution before establishing control devices.
        2231.
        1999.03 KCI 등재 서비스 종료(열람 제한)
        약용식물을 비롯하여 45종 식물체 지상부의 MeOH추출물을 대상으로 DPPH free radical소거법을 이용하여 항산화활성을 측정하였다. 그 결과 신나무(Acer ginnala Max.)의 추출물에서 가장 강한 활성(RC50 : 15μg)을 보였으며, 노각나무(Stewartia koreana, RC50 : 28μg)와 서어나무(Carpinus laxiflora, RC50 : 33μg)에서도 활성이 비교적 높았다. 신나무의 지상부로부터 DPPH free radical 소거 활성을 지표로 2개의 항산화 활성 물질을 분리하였다. 활성물질을 각종 기기분석을 통하여 3, 6-di-O-galloyl-1, 5-anhydro-D-glucitol(acertannin)과methyl-3, 4, 5-trihydroxybenzoate(gallicin)로 동정 하였다. acertannin(RC50 : 3.5μg)과 gallicin(RC50 : 2.8μg)은 기지의 항산화 물질인 BHA(RC50 : 14μg), vitamin E(RC50 : 12μg)보다 강한 항산화활성을 나타냈다.
        2234.
        1999.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The mechanism of natural removal of astringency and seasonal changes of tannin substance in sweet persimmon(Fuyu) and astrigent persimmon(Chungdo Bansi)were investigated. Tannin productivity of astringent persimmon fruit was higher than that of sweet perimmon fruit during growth. In the reactivity of tannin to acetaldehyde, it was observed that tannin from sweet persimmon have a milder chemical properties than that from astrigent persimmon. The threshold value of astringency on sweet persimmon tannin was higher than that of astrigent persimmon tannin. Tannin substances from sweet persimmon distributed mainly in lower molecular weight range at harvest stage, but those from astrigent persimmon distributed mainly in higher molecular weight range. Therefore, the natural removal of astringency was related to difference of tannin productivity, threshold value of astringency, reactivity and qualitative difference of tanni.
        2235.
        1999.02 KCI 등재 서비스 종료(열람 제한)
        Air quality modeling about coastal urban region such as Pusan shoud be consider shipping source emmited from ships anchoraging and running. It has been proved at our previous studies that the ratios of air pollutants emission amount in coastal area to inland are 12.2% for NO2 and 11.7% for SO2 and the air quality of coastal urban area consierably counts on ships. Also the dispersion pattern of the air pollutants followed local circulation system in this region. Therefore this study has been developed air quality model which can describe the formation, transport, transformation and deposition processes of air pollutants considering shipping source. Currently, restriction for emission amount of ships does not exist, so our study will be useful to set the emission standard and for devising air quality policy in coastal urban region.
        2236.
        1999.02 KCI 등재 서비스 종료(열람 제한)
        This study identified concentrations of air pollutants emitted from idling of vehicles such as cars, taxis, trucks, and buses. In this investigation we analyzed concentrations of SO2, NOx, CO, and CO2 emitted from exhaust pipe of vehicles as a function of vehicle type, mileage, exhaust volume, and fuel type using the GreenLine. Compact or light cars, which have relatively low exhaust volume, showed much higher exhaust concentrations of SO2, CO, and NOx than those emitted from vehicles with high exhaust volume. Vehicles using light oil showed much higher exhaust NOx concentrations than those of vehicles using gasoline. Vehicles using LPG and compact cars showed very high exhaust CO concentration compared to other vehicles. NOx exhaust concentrations were increased with increasing the mileage of vehicles.
        2237.
        1999.02 KCI 등재 서비스 종료(열람 제한)
        Four cast iron pipe sections containing 3 styrene butadiene rubber (SBR) gaskets (1 joint and 2 end caps) were filled with water and maintained at approximately 40 psi internal pressure. The pipe sections were placed inside 16 gallon drums filled with initially clean sand. Three of the tanks were subsequently contaminated with gasoline, gasoline spiked with pyrene and naphthalene, and toluene. The forth tank served as a control. The water inside each pipe was monitored over time for organic chemical contamination. Permeation of organic chemicals into the water inside the pipe systems was found to occur in all 3 contaminated pipe systems after approximately 100 days as measured organic chemicals concentrations were significantly above those in the uncontaminated cell. Flushing experiments in which the water inside the contaminated pipes was replaced with initially clean water showed that organic chemical concentrations inside the pipe rapidly (12 days) reached their preflushing levels.
        2238.
        1998.12 KCI 등재 서비스 종료(열람 제한)
        It is noted that the red tides and the oxygen-deficient water mass are extensively developed in Masan Bay during summer. The nutrients mass balance was calculated in Masan Bay, using the three-dimensional numerical hydrodynamic model and the material cycle model. The material cycle model was calibrated with the data obtained on the field of the study area in June 1993. The nutrients mass balance calculated by the combination of the residual currents and material cycle model results showed nutrients of surface and middle levels to be transported from the inner part to the outer part of Masan Bay, and nutrients of bottom level to be transported from outer part to inner part of Masan Bay. The uptake rate of DIN in the box A1(surface level of inner part) was found to be 337.5㎎/㎥ ·day, the largest value in all 9 boxes and that of DIP was found to be 18.6㎎/㎥·day in box A1, and the regeneration rate of DIN was found to be 78.2㎎/㎥· day in the box A3(bottom level of inner part), and that of DIP was found to be 18.6㎎/㎥· day in box A1. The regenerations of DIN and DIP in the water column of the entire Bay were found to be 7.66ton/day and 760㎏/day, respectively. And the releases of DIN and DIP from the sediments of the entire Bay were found to be 2.86ton/day and 634㎏/ day, respectively. The regeneration rate was 2.5 times as high as the release rate in DIN, and 1.2 times in DIP. The results of mass balance calculation showed not only the nutrients released from the sediments but the nutrients regenerated in water column to be important in the control and management of water quality in Masan Bay.
        2239.
        1998.12 KCI 등재 서비스 종료(열람 제한)
        A three-dimensional ecosystem model is applied to the Suyoung Bay, located at the southeastern part of Korea, to study of the material distribution in the time scale of several tens days. The model has included of the DIN(Dissolved Inorganic Nitrogen), DIP(Dissolved Inorganic Phosphate), phytoplankton, zooplankton and detritus, and also was coupled with the physical processes. The spatial distribution of chlorophyll-a and primary productivity in the model is determined by the physical and chemical-biological parameters. The horizontal distributions of the DIN, DIP and chlorophyll-a are decreased from the coast to the off-shore, though the nutrients show some more complicated pattern than the chlorophyll-a. The nutrient contents in the off shore are low, and thus a relatively low productivity(chlorophyll-a) are presented. On the whole, the distribution of the results of model are smoother than the observed ones and some small scale variation in the observed data cannot be reproduced by the model due to the resolution limits of model. However, the basic pattern and the quantitavities has been reproduced by the model well.
        2240.
        1998.12 KCI 등재 서비스 종료(열람 제한)
        This study was performed to determine the optimum coagulant dosing amount for effective treatment of raw water. The removal rate of turbidity and the variations of water qualities according to various dosage of coagulants such as Alum, PAC and PACS were investigated. The optimum coagulant dosing amount to make the lowest turbidity of water were 35㎎/ℓ of Alum, 30㎎/ℓ of PAC and l0㎎/ℓ of PACS in case of 5 NTU of raw water turbidity, and 30㎎/ℓ of Alum, 25㎎/ℓ of PAC and l0㎎/ℓ of PACS in case of 10 NTU of that, respectively. The removal rates of turbidity at 4 min. and 8 min. of settling time were 10 and 72% of Alum, 44 and 62% of PAC and 25 and 55% of PACS in case of 5 NTU, and 52 and 70% of Alum, 90 and 95% of PAC and 10 and 28% of PACS in case of 10 NTU, respectively. Judging from the settling capability of floc., the reaction time of floc. formation and removal efficiency of turbidity, PAC was evaluated as more effective coagulant than Alum and PACS. Also PAC was regarded as the most effective coagulant when the water supply was changed sharply and the fluctuation of the surface loading occured with wide and sharp in seettling basin. pH and alkalinity of the water were decreased with increasing coagulants dosage. But pH and alkalinity were not decreased below 5.8 which is the standard for drinking water quality, and l0㎎/ℓ which is the limit concentration of floc. breakage, respectively. Residual Al of the treated water was decreased with increasing coagulants dosage in case of 5 and 10NTU of raw water turbidity. KMnO_4 consumption of the water was decreased with increasing coagulants dosage. The reduction rate of KMnO_4 consumption at the optimum coagulants dosage were 39% of Alum, 18% of PAC and 11% of PACS in case of 5 NTU of raw water turbidity, and 42% of Alum, 27% of PAC and 36% of PACS in case of 10 NTU of that, respectively. Any relationship was not found between the removal rate of turbidity and KMnO_4 consumption. TOC of the water was a bit decreased with increasing coagulants dosage up to 30㎎/ℓ but not changed above 30㎎/ℓ of coagulants dosage. The degree of TOC reduction was increased in the order of Alum, PAC and PACS treatment. Zeta potential of the colloidal floc. at the optimum coagulants dosage was in the range of -20∼-15mV in case of 5 NTU of raw water turbidity and 0∼0.5mV in case of 10 NTU of that, respectively. Although the kinds and dosages of coagulants were different, zeta potential range were fixed under the conditions of the best coagulation efficiency.