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        검색결과 6

        1.
        2003.10 KCI 등재 서비스 종료(열람 제한)
        Pesticides were extracted from samples with 70% acetone and methylene chloride in order, and then cleaned up via open-column chromatography apparatus packed with florisil, and finally analyzed simultaneously the organophosphorus pesticides using GC/NPD. Ultra-2 and Ultra-1 fused silica capillary columns were used to separate and identify the products. Recovery of most analytes from soybean sample, taken from pesticide residues well, was greater than(80%) for all except(6) analytes. This method can simultaneously determine multiple pesticides with a high degree of accuracy and precision.
        2.
        2003.04 KCI 등재 서비스 종료(열람 제한)
        Pesticides were extracted from samples with 70% acetone and methylene chloride in order, and then cleaned up via open-column chromatography apparatus packed with florisil, and finally analyzed simultaneously the organochlorine and pyrethroid pesticides using GC(ECD). An ultra-2 fused silica capillary column was used to separate and identify the products. The resolution between the last isomeric peak of cypermethrin(59.987min) and the first isomeric peak of flucythrinate(60.043min) was not satisfactory. The last isomeric peak of fenvalerate(62.344min) and the first isomeric peak of fluvalinate(62.397min) were overlapped. Recoveries of soybean sample for the most pesticides were 73.3% to 102.4%. Detection limits were between 0.004 and 0.063㎍/㎎ when this method was used.
        3.
        2002.10 KCI 등재 서비스 종료(열람 제한)
        The growth and heavy metal experiments revealed oppositive interactions between toxic metals(Zn and Cd) and Mn when the coastal diatom T. pseudonana were used. Cd and Zn inhibited the algal growth rate only at low Mn ion concentrations and this effect could be accounted for an inhibition of cellular Mn take by the toxic metals. Mn and Zn inhibited cellular Cd take and this indicated a reciprocal effects among the metals with respect to metal take. Saturation kinetics modeling of the take data was consistent with two metals competing with each other for binding to the Mn take system and with both Cd and Mn being transported into the cell by that system. Mathematical modeling of Mn and Cd take data revealed evidence for a Cd efflux system.
        4.
        1998.12 KCI 등재 서비스 종료(열람 제한)
        The well-mixed room model has been traditionally used to predict the concentrations of contaminants in indoor environments. However, this is inappropriate because the flow fields in many indoor environments distribute contaminants non-uniformly, due to imperfect air mixing. Thus, some means used to describe an imperfectly mixed room are needed. The simplest model that accounts for imperfect air mixing is a two-zone model. Therefore, this study on development of computer program for the two-zone model is carried out to propose techniques of estimating the concentration of contaminants in the room. To do this, an important consideration is to divide a room into two-zone, i.e. the lower and upper zone assuming that the air and contaminants are well mixed within each zone. And between the zones the air recirculation is characterized through the air exchange parameter. By this basic assumption, the equations for the conservation of mass are derived for each zone. These equations are solved by using the computational technique. The language used to develope the program is a VISUAL BASIC. The value of air exchange coefficient(f_12) is the most difficult to forecast when the concentrations of contaminants in an imperfectly mixed room are estimated by the two-zone model. But, as the value of f_12 increases, the air exchange between each zone increases. When the value of f_l2, is approximately 15, the concentrations in both zone approach each other, and the entire room may be approximately treated as a single well-mixed room. Therefore, this study is available for designing of the ventilation to improve the air quality of indoor environments. Also, the two-zone model produces the theoretical base which may be extended to the theory for the multi-zone model, that will be contributed to estimate the air pollution in large enclosures, such as shopping malls, atria buildings, airport terminals, and covered sports stadia.
        5.
        1997.04 KCI 등재 서비스 종료(열람 제한)
        Organophosphate pesticides were extracted with 70% acetone and then transferred to dichloromethane. Extracts were applied to open-column chromatography with florisil The final extract was analyzed by gas chromatography with nitrogen-phosphorus detector(GC/NPD). Recoveries of the 18 organophosphate pesticides were ranged from 88.7% to 100.0% for the narrow-bore capillary GC(Ultra-2). The minimum detectable level of this analytical method was 0.019 - 0.035 ㎎/㎏. Sample throughput(extraction, open-column chromatography, and GC analysis) was decreased considerably (8h per sample).
        6.
        1996.12 KCI 등재 서비스 종료(열람 제한)
        The sediment in the highly contaminated Gamjeon brook was collected, mixed with the raw material of the tile, and then the commercial tile was produced using the mixture. The concentrations of the heavy metals in the mixture-before and after the tile was produced-were analyzed and the effects of the acid solution on the produced file were examined. The production of the tiles was successful and the result of heavy metal analysis showed that the concentration of Fe was the highest and that of Cd was the lowest The amount of heavy metal in the sediment - the raw material of the tile mixture was more than that of the produced tile. The elution concentration of the heavy metal by the acid solution(pH = 4 - 7) was low and the quality of the produced tile was better than the commercial tile. The result of this study suggested that the contaminated sediment was removed to produce good tiles, therefore the water pollution and soil pollution were reduced.