• Membrane and Water Treatment
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• 제2권1호
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• pp.63-74
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• 2011

A spiral wound nanofiltration (NF) membrane (GE Osmonics, DK 4040F) was used to remove pesticides from water. Several solutions of single pesticides and their mixtures were prepared. The pesticides initial concentration ranged from ca. 50 ng/L (single pesticide) to ca. 700 ng/L (as sum of 14 pesticides) and progressively increased with time since the NF experiments were carried out in a concentration mode up to a Volume Concentration Ratio, VCR = 10. Permeate flux and pesticides retention were evaluated as a function of the Volume Concentration Ratio. The permeate flux did not practically change by varying VCR. Pesticide retention was found to be around 97-98% both in the cases of single pesticide solutions and different mixtures of pollutants, and was not affected by the VCR. Pesticides concentration in permeate samples was found to be lower than the maximum concentration level fixed in European directive.

• 상하수도학회지
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• 제23권5호
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• pp.631-636
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• 2009

This study has its intention to investigate the water quality of non-point source which is runoff from roads. We have classified and selected twelve sites as city road, industrial road, national road and mountain road by considering their traffic volume and surroundings. Water quality was analyzed based on BOD, COD, SS, T-N and T-P and the concentrations were measured by sampling after rainfall with the interval of 10 minutes, 20 minutes, and 30 minutes. BOD was the highest in city road with 57.6 mg/L and the lowest in mountain road with 45.0 mg/L. For COD, the highest concentration in industrial road was 146.5 mg/L and the lowest was in mountain road with 98.0 mg/L. The run off concentration of SS was up to maximum 630.0 mg/L (average 280.4 mg/L) which was remarkable compared to other types of road. It showed its lowest concentration in national road with 76.0 mg/L. T-N and T-P were the highest in industrial road and the lowest in mountain road. We found out that the runoff concentration was high with large amount of traffic volume and it seemed to be high in city road and industrial road where they were largely affected by their surroundings. Relatively, national road and mountain road seemed to show low concentration as they have less traffic volume and less affected by their surroundings.

• 핵의학기술
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• 제27권1호
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• pp.29-35
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• 2023

Purpose The concentration of PSA (Prostate Specific Antigen) after radical prostatectomy in prostate cancer patients is a predictor of biochemical recurrence, and the AUA (American Urological Association) is defined as biochemical recurrence when the concentration of PSA is measured at 0.2 ng/mL or more, and when the concentration is measured at 0.2 ng/mL or more at the retest. This standard is also applied our hospital. In this laboratory, the PSA reagent using IRMA (Immunoradiometric Assay) is used, and the sensitivity at a very low value was not as good as the reagent used in the department of laboratory medicine. This study aims to increase the reliability of the results by improving the precision and sensitivity of very low values. Materials and Methods As a reagent for the study, PSA reagent using IRMA was used. As a method to improve the precision and sensitivity of very low values, a variation method on the serum volume(25 uL, 50 uL, 100 uL, 200 uL) was studied, and variation usefulness evaluation was conducted. The evaluation items were compared the results of precision, analytical sensitivity, recovery rate, dilution test, high-dose hook effect test, parallel test and very low concentration values(n = 20). Results The validation results were displayed in the order of 25 uL, 50 uL, 100 uL, 200 uL. As the serum volume increased, it was confirmed that CV (Coefficient of Variation)(%) improved. Analytical sensitivity(ng/mL) was 0.038, 0.041, 0.017, 0.015 and recovery rate(%) was 101±3, 101±3, 99±2, 97±4. very low concentration values(ng/mL) between each volume(n=20) were 0.135±0.068, 0.076±0.050, 0.048±0.034, 0.046±0.034. and high dose hook effect appeared as the serum volume increased. Conclusion Through the variation usefulness evaluation, it was confirmed that as the serum volume increased, the precision and sensitivity improved at very low concentration values. However, it is necessary to pay special attention to the occurrence of high-dose hook effect as the serum volume increases. In the case of tests that requires very low concentration values, it is thought that the reliability of the result will be increased if the variation method is properly used after the variation usefulness evaluation.

• 한국가축번식학회지
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• 제10권2호
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• pp.188-191
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• 1986

This experiment was carried out to examine the correlation among the semen characteristics of Holstein bulls. Seventy-two samples of semen were collected from 6 Holstein bulls, 2 to 10 years old. The characteristics of the semen were estimated by ordinary methods. The results obtained in this experiment were summarized as follows: 1. Semen characteristics on an average were 6.0 ml of volume, 16${\times}$108/ml of concentration, 92.4${\times}$108 of total sperm number(TSN), 72.1% of motility and 4.6% of abnormality. 2. Semen volume was positively high correlated (P<0.01) with total sperm number, but negative correlation was observed with the sperm motility (P<0.05) and semen concentration. 3. In relation to their age, older bulls semen volume and total sperm number were increased (P<0.01), but semen concentration and motility were decreased (P<0.01).

• 한국환경과학회지
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• 제15권6호
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• pp.601-606
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• 2006

The coal gasification fuel is important to replace petroleum fuel. Also they have many benefits for reducing the air pollution. Measurements on the combustion characteristics of synthetic gas from coal gasification have been conducted as compared with LPG in constant volume combustion chamber. The fuel is low caloric synthetic gas containing carbon monoxide 30%, hydrogen 20%, carbon dioxide 5%, and nitrogen 45%. To elucidate the combustion characteristics of the coal gasification fuel, the combustion pressures, combustion durations, and pollutants(NOx, $CO_2$, CO) are measured with equivalence ratios($\phi$), and initial pressures of fuel-air mixture in constant volume chamber. In the case of the coal gasification fuel, maximum combustion pressure and NOx concentration are lower rather than LPG fuel. However CO and $CO_2$ emission concentration are similar to that of LPG fuel.

• 한국자동차공학회논문집
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• 제11권5호
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• pp.83-88
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• 2003

Measurements on the combustion characteristics of dimethyl ether(DME:$CH_3$O$CH_3$) as compared with LPC in constant volume combustion chamber have been conducted. The DME is a good alternative fuel having oxygen component in fuel. To elucidate the combustion characteristics of dimethyl ether as a fuel, the combustion pressures, combustion durations, and pollutants(NOx, $CO_2$, CO) are measured with equivalence ratios(Ø), and initial Pressures of fuel-air mixture. In the case of DME, the NOx concentration peaks in leu flame Ø = 0.85~0.9, and $CO_2$ concentration peaks at Ø=1.1, while the CO concentration abruptly rises at the condition of fuel-rich mixtures.

• 한국초전도ㆍ저온공학회논문지
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• 제23권3호
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• pp.26-31
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• 2021

Advanced classification of Cs contaminated soil by using a magnetic force-assisted selection pipe was investigated. A selection pipe is a device that sort particles depending on their particle size, based on the relationship between buoyancy, drag, and gravity force acting on the particles. Radioactive cesium is concentrated in small-particle size soil components with a large specific surface area. Hence, the volume of the Cs contaminated soil can be reduced by recycling the large-particle size soil components with low radioactive concentration. One of the problems of the selection pipe was that the radioactive concentration of the stayed soil in the selection pipe exceeds 8000 Bq/kg, which is the standard value of recycling of Cs contaminated soil, due to low classification accuracy. In this study, magnetic fields were applied to the lab-scale selection pipe from upper side to improve the classification accuracy and to reduce the radioactive concentration of the stayed soil.

• 핵의학기술
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• 제12권1호
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• pp.66-73
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• 2008

Purpose: CA 19-9 need to examine a number of sample volume, and the postwar 200 U/ml concentration hook effect appears slight. Thus, the antibody-antigen reaction, and by reducing the amount of (sample volume), they can hook effect to minimize the impact of the sample volume and relevance know, I saw the hook effect. In addition, the current maximum of using the standard concentration of the reagent in 240 U/ml increase more than the standard concentration can be seen knows. Material and Method: 5 U/ml and under, make a few low concentration of serum pool from the high concentration of the sample hook effect together with a standard concentration of about 500 to meet the production. The reagents used in experiments are currently using SNUH NM experiment. Orignal method along with the experiment is to 25 ul sample volume (1 / 4), 50 ul (1 / 2), 100 ul (Orignal method) in the experiment. My greatest concentration of the reagent concentration of approximately two times the standard concentration of production. When was the last to make the first experiment, as measured by the standard concentration after that. The new inspection information through a standard solution modified by entering values in them. Results: 100 ul, and to apply the new standard concentration y = 1.3021x - 10.97, $R^2$ = 0.9844. Overall, the results showed a similar orignal method. Because of the concentration in the value of more than 240 U/ml, but it is an overall value that can be made out of a similar value When I put the 50 ul y = 1.045x + 9.5861, $R^2$ = 0.9428. Overall orignal method and the results of a similar value. 50 ul, and to apply the new standard concentration y=1.2006x+11.252, $R^2$=0.9423. Showing a slightly lower value compared with orignal method. Because of the concentration in the value of more than 240 U/ml, but it is an overall value that can be made out of a similar value. When I put the man 25 ul y=0.6012x+24.755, $R^2$=0.4033. Results showed that very small amounts of sample are insecure inside and showed a lower middle cpm orignal method and showed a lot of mismatched. Conclusions: 25 ul of the sample volume is not possible to use the instability had, when I put the 50 ul of the orignal method can be used to show a similar concentration. The new values are slightly lower concentration, The new values are slightly lower concentration, concentration, which are likely due to the lack of data has had a little gap between the sample showed 80 to 200 U/ml additional experiments seem to do. Apply a new 100 ul concentration values are applied to a large crowd is not even in sight. But this way the concentration of 100 to more 400 U/ml gather further experiments should possible adds.

• 환경생물
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• 제29권4호
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• pp.312-320
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• 2011

본 연구는 해양 식물플랑크톤의 개체수 및 생체량과 chlorophyll $a$ 농도간의 연관성을 파악하기 위하여 2000년부터 2010년까지 인천, 통영, 울산 해역의 34개 정점에서 1160개 시료를 분석하였다. 연구결과 개체수와 chlorophyll $a$ 농도가 생체량과 chlorophyll $a$ 농도보다 높은 상관성을 보여 우리나라 연안해역에서는 1차 생산의 분석에 있어서 개체수 지표를 사용하는 것이 생체량을 사용하는 것보다 더 효율적일 것으로 판단된다. 그러나 좀 더 자세한 결과를 도출하기 위해서는 시기별로 보다 많고, 정확한 생체량 데이터를 확보하고, 시기별 chlorophyll 함량 자료의 축적과 함께 국내 연안에서 적용 가능한 모델 구축이 반드시 필요하다.

• 한국환경과학회지
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• 제22권1호
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• pp.25-35
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• 2013

The concentration of organic compounds was analyzed at each step of BAC process though $BDOC_{total/rapid/slow}$. Further, bacteria communities and biomass concentrations measured FISH and ATP methods were analyzed. The bed volume (BV) of steady state is different from that of based on assessment of organic compounds removal. Bed volumes in DOC, $BDOC_{rapid}$ and $BDOC_{total/slow}$ removal at steady state were around 27,500 (185.8 day), 15,000 (101.4 day) and 32,000 (216.2 day), respectively. A biomass didn't change after the bed volume reached 22,500 (152.0 day) according to analyzing ATP concentration of bacteria. The concentration of ATP was 2.14 ${\mu}g/g$ in BV 22,500 (152.0 day). The total bacterial number was $4.01{\pm}0.4{\times}10^7$ cells/g at the bed volume 1,150 (7.8 day) (the initial operation) and the number of bacteria was $9.27{\pm}0.2{\times}10^9$ at the bed volume 58,560 395.7 day) that increased more than 200 times. Bacterial uptrend was reduced and bacterial communities were stabilized since BV 18,720 (126.5 day). When BV were 1,150 (7.8 day), 8,916 (60.2 day), 18,720 (126.5 day), 31,005 (209.5 day), 49,632 (335.3 day), 58,560 (395.7 day), a proportion of total bacteria for the Eubacteria were 60.1%, 66.0%, 78.4%, 82.0%, 81.3% respectively. ${\gamma}$-Proteobacteria group was the most population throughout the entire range. The correlation coefficient ($r^2$) between Eubacteria biomass and ATP concentration was 0.9448.