A study on the subsidence risk evaluation using 3-D rock mass collapse simulation for abandoned mines

손민,문현구,김양균,이승아 한국자원공학회 2017 Geosystem engineering Vol.20 No.1

This paper suggests a way to evaluate the subsidence risk applicable to abandoned mines. For the subsidence risk evaluation, a diagram modified from Sakurai’s tunnel stability evaluation diagram was developed. To check the feasibility of the modified diagram, two typical mines to represent Korean mines, one gold mine including one steep goaf and one coal mine including two gently sloped goafs were selected and 3-D numerical analyses for the sections in which actual subsidence was occurred were performed. In the numerical analyses, the variation in relative displacement strain between the observation point and reference point placed over the goafs according to the location of the points was analyzed, and the strain was applied to the modified diagram to evaluate the subsidence risk. The results show that the critical factors in the subsidence risk evaluation are the relative locations of the observation and reference points from the goafs as well as joints existing between goafs and the ground.

Optimization of Dextran Production from Leuconostoc mesenteroides CS-5 Isolated from Chonggak Kimchi

손민,권오식 계명대학교 자연과학연구소 2016 Quantitative Bio-Science Vol.35 No.2

The purpose of our study was to optimize the dextran production in Leuconostoc mesenteroides CS-5, which was isolated from Chonggak kimchi. To measure dextran productivity, rheological analysis and the dinitrosalicylic acid method were applied. For optimization of dextran production, 10-30% sucrose (w/v) was added to MRS medium; the highest viscosity value was found after the addition of 30% sucrose (0.153 Pa·sn), which was much higher than that found in the control (0.01 Pa·sn). However, the production of dextran by L. mesenteroides CS-5 was entirely inhibited by the addition of 17% maltose (w/v) to medium containing 30% sucrose. A subsequent test with skim milk revealed that most vigorous dextran production occurred during cultivation at 22°C with 1.5% skim milk - 0.30 Pa·sn (compared to 0.22 Pa·sn at 25°C). L. mesenteroides CS-5 is regarded as a facultative psychrophile (cold-loving bacteria). The addition of CaCl2 increased the viscosity of the medium, owing to the production of dextran, by more than two-fold. The optimum concentration of CaCl2 was determined to be 0.01% (w/v) which resulted in a viscosity value of 1.35 Pa·sn. Comparative analysis was performed using dinitrosalicylic acid tests to measure amounts of dextran according to absorbance (O.D.) at 550 nm. The highest dextran production occurred within 48 hr of incubation when using additions of 1.5% skim milk and 0.01% CaCl2 (113.24±0.80 and 112.13±0.2, respectively). In an attempt to enhance dextran production further, the number of cells inoculated into the optimized medium was increased from 109 to 1010 and 1011 cells per 10 ml. As expected, the concentration of dextran was significantly increased by the inoculation of more cells. For 36-hr incubation, values of O.D. produced by inoculation of 1.0×1011 cells reached 123.75±0.25 (30% sucrose), 121.65±0.38 (1.5% skim milk), and 119.80±0.28 (0.01% CaCl2); compared to 55.40±0.44 (30% sucrose), 76.83±0.06 (1.5% skim milk), and 119.80±0.28 (0.01% CaCl2) when 1010 cells were used. During 48-hr incubation, the highest dextran production was achieved with the addition of 1.5% skim milk and 1.0×1011 cells/10 mL (152.07±0.78), whereas the values resulting from additions of 30% sucrose and 0.01% CaCl2 treatments were 124.33±0.03 and 142.10±0.87, respectively. This implies that those values are the maximum values achievable for dextran production in L. mesenteroides CS-5. Thus, increasing the number of cells inoculated can facilitate optimum dextran production.

반도체 기업의 경영효율성과 성장가능성을 고려한 포트폴리오 선택 전략

손민 한국경영과학회 2012 한국경영과학회 학술대회논문집 Vol.2012 No.5

폐광산 지반의 역학적 특성 추정을 위한 최적설계 기법에 관한 연구

손민,문현구,정혁상,김영수,박성현,Son, Min,Moon, HyunKoo,Jung, HyukSang,Kim, YoungSu,Park, SungHyun 한국터널지하공간학회 2020 한국터널지하공간학회논문집 Vol.22 No.1

국내 폐광산은 다양한 형태의 침하를 발생시키고 있으며 이러한 침하의 예측 및 위험도의 평가는 대단히 어려운 실정이다. 기존 수치해석을 활용한 침하 예측 및 위험도 평가 연구에서는 지질구조와 지반조건에 대해 통합 물성을 적용하고 채굴적 주변 소성영역을 해석하는데 그치고 있다. 또한 입력정보를 확보하는데 있어 제한된 자료밖에 파악할 수 없는 현실적인 한계점이 존재하며 이는 곧 수치해석 결과의 신뢰성 저하로 연결된다. 본 연구에서는 실제 침하가 발생한 폐광산을 대상으로 현장 지질구조 및 지반정보를 적용하여 2차원 모델링을 수행하였다. 또한 지반물성을 수정하여 해석결과와 실제 침하지 정보(규모, 위치)의 차이가 최소가 되도록 수치해석을 반복하여 해석모델을 보정하였다. 이러한 보정에 있어 최적화 기법을 적용하여 자동화하였으며 다수의 지반물성을 나누어 고려하는 단계적 최적설계 기법을 개발하였다. The domestic abandoned mines are generating subsidence and it is difficult to predict this subsidence and evaluate the risk. The study of the subsidence risk evaluation using the existing numerical analysis only applies the integrative property to the geological structure and ground condition, and analyzes the goaf peripheral plastic domain. Also, there is a realistic limit that only restricted materials can be apprehended in securing the input information, which leads to the low reliability of the numerical analysis result. In this study, 2-dimensional modeling was performed by applying the field geological structure and ground information targeting abandoned mine where the subsidence occurred. Also, the analysis model was revised by repeating the numerical analysis for the difference between the real subsidence ground information and the analysis result to be minimized by modifying the ground property. This revision was automated by applying the optimization technique and the gradational optimal design method dividing multiple ground properties was developed.

유행성 출혈열의 임상검사 소견

손민,김인환 육군본부 1962 군진의학 Vol.9 No.2

Science와 Business, 그리고 Law 가 만나는 곳 : 특허 (Patent)

손민 한국생물공학회 2011 한국생물공학회 학술대회 Vol.2011 No.10

수치해석을 이용한 금곡광산 지반안정성 평가

손민 한국암반공학회 2013 한국암반공학회 학술대회 및 세미나 자료집 Vol.2013 No.10

반도체 기업의 경영효율성과 성장가능성을 고려한 포트폴리오 선택 전략

손민 대한산업공학회 2012 대한산업공학회 춘계학술대회논문집 Vol.2012 No.5

제1형 당뇨병 아동의 긍정적 심리요인에 대한 탐색적 연구: 주관적 행복감과 삶의 만족감을 중심으로

손민,김의연,이지은,김광희 한국아동간호학회 2015 Child Health Nursing Research Vol.21 No.2

Purpose: The purpose of this study was to describe the subjective happiness and satisfaction with life of children with type 1 diabetes and explore related factors. Methods: A descriptive cross-sectional study design was used and the study was conducted with children at a diabetes camp. Data were collected using a self-report questionnaire to explore positive and negative psychological factors. The questionnaire included Subjective Happiness Scale, Satisfaction with Life Scale, Perceived Stress Scale and the Center for Epidemiological Studies Depression Scale for Children (CES-DC), Multidimensional Scale of Perceived Social Support, and General Self-Efficacy Scale. Results: Data from 15 children were used for data analysis. The correlational analysis results showed that subjective happiness was positively correlated satisfaction with life, social support, and self-efficacy, and was negatively correlated with perceived stress. Satisfaction with life was positively correlated social support, and was negatively correlated with perceived stress. Conclusion: Results indicate that the positive psychology factors were closely related with social support and self-efficacy and may alleviate perceived stress and depressive feelings. Therefore, researchers and clinicians should include positive psychological factors in their health management model for children with chronic illness.

[독자로부터…] 4월호를 읽고

손민 새가정사 2011 새가정 Vol.58 No.634