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Chitosan-oligosaccharides가 병원성 대장균의 소수성(疎水性)에 미치는 영향
최현성,한호재,김희경,김희선,강문일,Choi, Hyun-sung,Han, Ho-jae,Kim, Hee-kyung,Kim, Hee-sun,Kang, Mun-il 대한수의학회 1999 大韓獸醫學會誌 Vol.39 No.3
The purpose of this study was to evaluate effect of chitosan-oligosaccharides (CHIOL) on hydrophobicity of pathogenic E coli including a field isolate from suckling piglet with diarrhea, E coli-O157 : H7, and E coli-O149 : K88ac. E coli field isolate appeared adhesion of 100% to n-hexadecane between 0.00125% and 0.05% CHIOL. E coli-O157 : H7 occurred adhesion of 69% and 64% under the level of 0.00125% and 0.025% CHIOL, respectively. E coli-O149 : K88ac showed adhesion of 100% in higher than 0.025% CHIOL. For cationic action, the adhesion of E coli isolate and E coli-O149 : K88ac to n-hexadecane were inhibited at level of higher than 10mM $Ca^{2+}$ but did not induce any difference among the concentrations used(p < 0.01). However, the adhesion of E coli-O157 : H7 to n-hexadecane was inhibited at level of higher than 50mM $Ca^{2+}$. In a field trial, control piglets showed average mortality of up to 58% during 3 days after the onset of diarrhea. In contrast, the prevalence of E coli-induced diarrhea in CHIOL-treated groups without mortality was dropped down to average 34% on the 1st day after the treatment of CHIOL, and average 2% on the 4th day. After then, piglets with diarrhea was not present. In conclusion, the low concentrations of CHIOL were most likely to associate with the enhancement of hydrophobicity to pathogenic E coli. Calcium inhibited the hydrophobicity of E coli by CHIOL. These results suggested that CHIOL could be played an efficient and reliable role in treating enteric colibacillosis of piglets.
장경간 철도 교량에 적용된 슬라이딩 궤도와 레일신축이음장치의 궤도-교량 상호작용 비교
이경찬,장승엽,이정휘,최현성,Lee, Kyoung Chan,Jang, Seung Yup,Lee, Jungwhee,Choi, Hyun Sung 한국전산구조공학회 2016 한국전산구조공학회논문집 Vol.29 No.2
슬라이딩 궤도는 콘크리트 궤도와 교량 바닥판 사이에 저마찰 슬라이드층을 두어 레일신축이음장치와 같은 특수 장치를 적용하지 않고도 궤도-교량 상호작용 효과를 효과적으로 저감시킬 수 있는 새로운 궤도 시스템으로 개발되고 있다. 이 논문에서는 장경간 교량에 슬라이딩 궤도와 레일신축이음장치를 각각 적용한 경우에 대하여 궤도-교량 상호작용해석을 수행하고 그 결과를 비교 검토하였다. 대상교량은 상호작용 효과를 극대화하기 위하여 9경간 연속 PSC교와 2경간 연속 강합성교를 포함하며, 총 연장 1,205m, 최대 고정지점간 거리 825m인 장경간 교량을 선정하였다. 해석결과 슬라이딩 궤도는 레일신축이음장치를 적용한 경우보다 레일 부가 축력이 더 작은 것은 물론, 지점부에 재하되는 수평 반력 또한 작게 나타나 궤도-교량 상호작용 저감 효과가 뛰어난 것으로 확인되었다. 반면 슬라이딩 궤도는 온도하중에 의해 높은 슬래브 축력이 발생되므로, 궤도 설계 시 슬래브 축력에 대한 단면 설계에 주의를 기울일 필요가 있다. Sliding slab track system, which consists of low friction sliding layer between track slab and bridge deck, is recently devised to reduce track-bridge interaction effect of continuously welded rail(CWR) without applying special devices such as rail expansion joint(REJ). In this study, a series of track-bridge interaction analyses of a long-span bridge with sliding slab track and REJ are performed respectively and the results are compared. The bridge model includes PSC box girder bridge with 9 continuous spans, and steel-concrete composite girder bridge with 2 continuous spans. The total length of the bridge model is 1,205m, and the maximum spacing between the two fixed supports is 825m. Analyses results showed that the sliding slab track system is highly effective on interaction reduction since lower rail additional axial stress is resulted than REJ application. Additionally, horizontal reaction forces in fixed supports were also reduced compared to the results of REJ application. However, higher slab axial forces were developed in the sliding slab track due to the temperature load. Therefore, track slab section of the sliding slab track system should be carefully designed against slab axial forces.
김대식 ( Kim Dae-sik ),최현성 ( Choi Hyun-sung ) 한국농공학회 2007 한국농공학회논문집 Vol.49 No.6
This study aims to analyze temporal variation of rural tourist potential in village level. In order to analyze the temporal variation, this study applied a green-tourism potential evaluation model(GPEM) to a study area, Namil-myun with 18 villages, which located on county of Kumsan, province of Chungnam. GPEM consists of two factors about human resources, which is quantified by resident population of the village who will be participated in village management for green-tourism, and amenity resources, which is calculated by an evaluation table with 31 criteria and their weighting values. Data surveying for the study area was performed at August 2003 and 2006, respectively, in order to quantity the 31 evaluation criteria of GPEM. From the analysis results, the amenity resources with three sub-classes of industrial, natural, and social resources showed that the evaluation values of 2006 were increased in more than those of 2003, displaying the increase rate of ranging from 108% to 112% in the three sub-classes, except of one village in social resources and three village in natural resources with reduction. In human resources, the evaluation values of 2006 were highly increased more than those of 2003, showing the rate of 556% in the gradient of linear regression line. In green tourism potential in each village, the evaluation results for two time series showed that the potential is increased by time, which the increase rate of the potential is 114%. Ultimately, the results of this study enable us to realize that the green-tourism potential in each village over time is increased, for example, due to developing new facilities in the village by investment of government and participating in rural tourism by resident people over time. From the analysis and results, the methodology of this study can be applied to analyze the temporal variation of the potential for villages having investment from government.
어메니티 자원을 활용한 마을단위 농촌관광 잠재력 평가에 관한 연구
김대식 ( Kim Dae-sik ),최현성 ( Choi Hyun-sung ) 한국농공학회 2005 한국농공학회 학술대회초록집 Vol.2005 No.-
This study aims to suggest an evaluation methodology of green-tourism potential for village level with amenity resources in rural areas. The amenity resources system was classified into three sub-classes(social, industrial, and natural/cultural/historical resources) and a relationship diagram between three classes and tourists' behavior was also defined. The methodology considers human resources in the village including the three sub-class amenity resources. The table and diagram were applied to make renewal plan for rural villages of the study area, Nami-myun, Keumsan-gun, Chungnam province, so that the development scheme for the villages was suggested reasonably by the new findings of this study.
화학물질의 누출과 피부접촉에 의한 재해자 및 사고사망자 발생현황 조사
이권섭 ( Kwon Seob Lee ),최현성 ( Hyun Sung Choi ),이하영 ( Ha Young Lee ),신경민 ( Kyung Min Shin ),최흥구 ( Heung Koo Choi ),이인섭 ( In Seop Lee ) 한국산업보건학회 (구 한국산업위생학회) 2020 한국산업보건학회지 Vol.30 No.1
Objectives: We investigated the status of accidents and deaths caused by chemical leakage and skin contact in Korea. The purpose of this study was to produce and provide technical reference data for the efficient management of accidents and the rational management of accidental chemicals. Methods: Accidents and deaths caused by chemical leakage and skin contact in industry were investigated. Based on 68 accident reports related to chemical leakage and skin contact, the causes of accidental deaths were analyzed. In addition, we investigated the chemical substances and articles that caused these accidents and deaths. Based on the results of the investigation, the causes of accidents caused by chemical leakage and skin contact were identified and practical management measures for the chemicals were suggested. Results and Conclusions: In 2018, 372 people suffered from chemical leaks and skin contact, up by 123 (about 49.4%) from the previous year. The number of accident deaths was 14, an increase of five (about 55.6%) from the previous year. In the last three years (2016-2018), 91 chemical substances and article groups were involved in accidents caused by chemical leakage and skin contact. There were 16 chemical substance and article groups involved in accidental deaths. There were ten cases of accidents involving two or more casualties due to chemical leakage and skin contact, and 23 deaths occurred. Most of these accidental deaths were caused by subcontractor workers outsourcing risks. Therefore, there is an apparent need to strengthen the responsibility for safety and health among subcontractors.