• Proceedings of the Korea Water Resources Association Conference
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• 1986.07a
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• pp.131-145
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• 1986

흐름수역에서 연직상향으로 방류되는 평면부력\ulcorner의 거동이 연속방정식, 운동량방정식 및 추적물수송식의 기본방정식에 의하여 수치적으로 해석된다. 난류확산에는 Prandtld의 혼합거리이론을 도입한 난류수송모형이 이용된다. 수치해 과정은 기본방정식을 유함수(stream function)식, 와도수송(vorticity transport)식으로 변환한 후, \ulcorner방류속도와, 방류구폭 등으로 표현되는 변수와 흐름을 지배하는 무차원 매개변수를 도입하여 무차원 형태로 표현하는 부분과 successive under-relaxation과 Gauss-Seidel반복법으로 수행하는 부분으로 이루어진다. 적절한 relaxation 계수를 선정하므로써 안정되고 수렴성이 좋은 계산이 수행된다. \ulcorner방류 속도와 가로흐름 속도의 비가 속도비(Velocity ratio)로 정의되며 속도비가 8 - 15의 범위에서 부력\ulcorner으로 인한 주변흐름수역의 속도변화 온도상승범위, 흐름상태(유선) 및 와도가 조사되었으며 \ulcorner의 경로에 대하여 속도비와 방류밀도후르드수의 영향이 또한 조사되었다. \ulcorner중심선의 속도와 온도변화, 국부밀도후르드수의 변화가 구해지며 퍼짐율(dispersion ratio), 확산비(spreading rate)가 방류밀도후르드수, 국부밀도후르드수 및 방류구로부터의 경로의 항으로 해석되었다. 또한 속도와 온도 분포에 상사(similarity)가 존재함이 밝혀졌으며 본 연구와 같은 조건의 범위에서는 Gaussian분포를 이용한 적분형해석(intergal type analysis)이 가능한 것으로 사료된다.

• Progress in Medical Physics
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• v.19 no.2
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• pp.113-119
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• 2008

In this study, we have estimated error of calculation results for 5-type RTP systems and investigated a toleration for error of the RTPs referenced from the evaluation items of AAPM Report-62. For this study, we have introduced the concept of 'normal dose rate(NDR)' and compared the results of experiment and calculation from RTPs at the same reference level. The results from all RTPs were satisfied at various field shapes and heterogeneous phantom materials except the surface irregularity.

• Korean Journal of Food Science and Technology
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• v.33 no.4
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• pp.423-426
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• 2001

Electron spin resonance (ESR) spectroscopy was used to investigate the effect of irradiation dose on irradiated dried fruits. Dried banana, pineapple and pistachio were irradiated with doses of 0, 0.5, 1, 2 and 5 kGy at room temperature using a Co-60 irradiator. Multiplet ESR signals were observed in irradiated dried banana and pineapple, and singlet ESR signal was observed in irradiated pistachio, while these characteristic signals were not detected in non-irradiated samples. Since the amount of free radicals linearly increased with the applied doses $(0.5{\sim}5\;kGy)$, highly positive correlation coefficients $(R^2=0.9874{\sim}0.9974)$ were obtained between the irradiation doses and the corresponding free radical concentrations. The characteristic ESR signals were observed in irradiated samples even after 40 days of storage at room temperature.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.2
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• pp.261-266
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• 2005

Gamma irradiation at 30 kGy was applied to porridge to evaluate its possible genotoxicity. The genotoxicity of irradiated porridge was evaluated by Salmonella Typhimurium reversion assay, chromosomal aberration test and in vivo micronucleus assay. The results were negative in the bacterial reversion assay with S. Typhimurium TA98, TA100, TA1535 and TA1537. No mutagenicity was detected in the assay both with and without metabolic activation. In chromosomal aberration tests with CHL cells and in vivo mouse micronucleus assay, no significant difference in the incidences of chromosomal aberration and micronuclei was observed between nonirradiated and 30 kGy-irradiated porridge. These results indicate that porridge irradiated at 30 kGy did not show any genotoxic effects under these experimental conditions.

• Korean Journal of Ichthyology
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• v.24 no.2
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• pp.84-93
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• 2012

Fish species composition and abundance in the waters of nearby Nakdong River estuary were investigated non-continuously and seasonally by shrimp beam trawl in summer 2007, winter 2009, and from spring 2010 to autumn 2010. During the study period, total fish species were collected 92 species, 36 families in study area. Shannon index was 1.893~2.962, and evenness was 0.050~0.231. Fish species composition was shown interannually and seasonally variations in the waters of nearby Nakdong River estuary. We carryed out cluster analysis to contain the data in previous and current study. Fish species composition was divided 3 groups which were 1987~1988 and 1998, 2001~2002, and 2007~2008 and 2009~2010. Average and minimum length in this study was longer than its in previous studies, and length range in this study was wider than its in previous studies, too. Dominant fish increased individuals and weight per unit area in this study. Especially Lophius litulon, Raja kenojei, Eopsetta grigorjewi, and Zeus faber were much better than past 2002. Liparis tanakai, Repomucenus valenciennei and Leiognathus nuchalis were dominant fish in previous study, but those decreased individuals and weight per unit area in this study.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.84-92
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• 2005

본 연구에서는 우리나라 기업을 대상으로 수행한 설문조사 결과를 바탕으로 선별된 경영과학 기법이 실제 기업의 의사결정에 활용되는 빈도 및 수준, 현재 업무에 기여하는 정도, 적용 범위, 실행상의 문제점, 그리고 앞으로 기여가 기대되는 업무 범위 등에 대하여 논의한다.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2005.04a
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• pp.28-31
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• 2005

본 연구에서는 영국, 미국 등 선진국 레이저 안전관리 프로그램을 조사하여 우리나라 실정에 적합한 레이저 안전관리자 범위를 선정하고 그에 맞는 교육프로그램을 제안하는데 기초자료로 활용하고자 한다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.616-620
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• 2002

가청범위의 주파수보다 낮은 소리, 즉 초저주파음과, 가청음 중 주파수가 낮은 음을 합하여 저주파음으로 분류하기도 하는데, 대략 100Hz 이하의 주파수를 갖는 음을 가리킨다. 인간이 느끼는 저주파음에 대한 영향은 여러 범위로 조사되고 있으며 주로 청력손실과 불쾌함에 미치는 영향에 초점을 맞추고 있다.(중략)

• The Korean Journal of Pesticide Science
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• v.2 no.1
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• pp.65-69
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• 1998

To determine the amount of total bromide as 2-bromoethanol, the domestic agricultural products such as rice, barley, carrot, cucumber, apple, tomato, squash, green pepper, melon, strawberry, grape, peach, potato and celery were analyzed by GC/MSD as well as GC/ECD. The bromide was detected in most of the domestic samples and the highest bromide residue determined was 13.2 ppm in barley. The imported agricultural products including melon, kiwi, lemon, pineapple, banana, orange and grape were also analyzed for the bromide. The bromide was also detected in most of the imported ones and the highest bromide residue determined was 12.3 ppm in pineapple. In addition, the bromide residue in instant noodle spices was monitored for 4 years, recently. As results, in 1994, the bromide content was in the range of non-detection to 2.4 ppm (average 1.1 ppm) from 22 out of 24 samples; in 1995, the bromide content was 1.0 and 2.2 ppm from 2 out of 37 samples; in 1996, the bromide content was in the range of 0.7 to 37 ppm (average 12.4 ppm) from all 11 samples; and in 1997, the bromide content was in the range of 0.2 to 4.6 ppm (average 1.2 ppm) from all 59 samples. However, none of sample analyzed for the bromide was exceeded Maximum Residue Limit(s) of Korea and Codex in these survey.

• Journal of Life Science
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• v.22 no.3
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• pp.324-331
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• 2012

Bacteriological examination of spring water in Jeju City was conducted. A total of 21 spring water samples were collected from January to April, 2010. During the study period, the range of temperature was 0.6 to $15.4^{\circ}C$, and the results of the analyses showed that hydrogen ion concentrations (pH) for spring water were 0.43 to 7.9. Salinity levels for the samples averaged from 3.0 to 1.64%, and levels of water-dissolved oxygen were 1.85 to 6.06 mg/l. The range of total coliforms in spring water samples at 21 stations located in the designated spring water were <1.8->1,600 MPN/100 ml. Furthermore, the range of geometric means of total coliforms was 9.9-151.6 MPN/100 ml, while the range of fecal coliforms in spring water samples at 21 stations located in the designated spring water area was <1.8->1,600 MPN/100 ml. Finally, the range of geometric mean of fecal coliforms was 3.1-151.6 MPN/100 ml. The level of microbial contamination was examined in 21 samples for indications of bacterial contamination such as heterotrophic bacteria, Escherichia coli O157:H7, Salmonella spp., Vibrio parahaemolyticus, Staphylococcus aureus, and Shigella spp. were frequently detected in the spring water. Salmonella spp., Shigella spp., Vibrio parahaemolyticus, and S. aureus were detected in the range of $0-0.5{\times}10^1$, $0-0.1{\times}10^1$, $0-0.1{\times}10^1$, and $0-0.3{\times}10^1$ CFU/ml, respectively, while E. coli O157:H7 was not detected in the examined spring water samples.