석탄광 폐석적치장에서의 산성 암석 배수 발생 평가 연구

이현석,고주인,지상우,김선준,정영욱 한국자원공학회 2006 한국자원공학회지 Vol.43 No.5

Waste rock dumps of two abandoned mines(the S-J and the D-W) and also of an operating mine (the K-S mine) were analyzed with the objective of assessing Acid Rock Drainage (ARD) in terms of seepage and its characteristics. In the study, it was also attempted to see whether the seepage has potential health hazard. The results of the study to ARD generation assessment in the abandoned mine case show that Net Acid Producing Potential (NAPP) of the S-J mine can be as high as 180.24 ㎏ H2SO4/t equivalent of acidity. NAPP of the D-W mine was measured having acidity of 20.99 ㎏ H2SO4/t. The case of K-S mine currently being operated was compared with the two study areas of the S-J and the D-W mines. NAPP of the K-S mine appeared low with 11.47 ㎏ H2SO4/t but was confirmed that the ARD generation potential exists. In the results of seepage analysis, pH data ranged from 2.18 to 3.31 and high concentrations of Fe, Al, Mn, SO4-2 in the S-J mine and the D-W mine of waste rock dump were found out. This result shows that the water resources surrounding waste rock dumps are likely to be affected by this seepage posing health hazards. The pH of seepage (4.33~4.56) in K-S mine waste rock dump was high compared to other two study areas. But concentrations of Al, Mn, and SO42- appeared about 20, 40, and 2500 mg/l respectively. Therefore, it was concluded that waste rock dump of K-S mine drainage without treatment can generate significant pollution. A comprehensive environmental management plan is also necessary to control the problems of drainage. 폐광된 광산의 폐석적치장과 가행중인 광산의 폐석적치장을 대상으로 폐석의 산 발생 특성 및 침출수의 특성을 분석하여 폐광 후에 진행될 수 있는 광해 발생을 예측해 보았다. 폐석의 산 발생 평가 결과 이미 폐광된 S광산 J광업소의 경우 최대 순 산 발생 능력(NAPP)이 180.24 ㎏ H2SO4/t 로 높게 나타났으며, D-W광산의 경우도 마찬가지로 최대 순 산 발생 능력이 20.99㎏ H2SO4/t 로 높게 조사되었다. 현재 가행중인 K광산 S광업소는 두 연구지역에 비해 최대 순 산 발생능력이 11.47 ㎏ H2SO4/t 로 낮게 조사되었지만 ARD 발생 암석이 존재하는 것으로 나타났다. 침출수 조사 결과 S광산 J광업소와 D-W광산의 폐석적치장에서는 pH가 2.18~3.31의 범위를 갖고, 고농도의 Fe, Al, Mn 및 SO42-함량을 보이는 침출수가 하부로 유출되고 있었으며, 이로 인하여 주변수계에서 적화현상(Yellowboy)을 확인할 수 있었다. K광산 S광업소의 폐석적치장 하부에서도 pH가 4.33~4.56으로 다른 두 연구지역에 비해 높긴 하나, Al, Mn 및 SO42-의 농도가 각각 약 20, 40, 2500mg/l로 오염된 침출수가 유출되고 있다. 따라서 K광산 S광업소의 폐석적치장을 현 상태로 조치 없이 방치한다면 폐광 후 지속적인 침출수의 유출에 의한 환경오염문제가 유발될 우려가 있다. K광산 S광업소를 비롯한 가행중인 대형 탄광들에 대해서 가행단계에서부터 폐석적치장으로부터의 산성배수의 발생에 대한 예측을 수행한다면, 적절한 관리방안을 마련함으로서 폐광 후 발생할 수 있는 산성침출수에 의한 광해에 대해 대비 할 수 있을 것이다.2006년 8월 10일 접수, 2006년 9월 19일 채택1) 한국지질자원연구원 지질환경재해연구부2) 한양대학교 지구환경시스템공학과*Corresponding Author(이현석)E-mail; kamuixc@hanmail.netE-mail; Korea Institute of Geoscinece and Mineral Resources 30, Gajeong-dong, Yuseong-gu, Daejeon 305-350, Korea

Detection of Polyps Including Adenomas in the Ascending Colon by Cap-assisted Chromocolonoscopy with Indigo Carmine

이현석 대한장연구학회 2014 Intestinal Research Vol.12 No.1

Tunable optical and electrical properties in 2D semiconductors andtheirapplications

이현석 한국진공학회 2018 한국진공학회 학술발표회초록집 Vol.2018 No.8

조기(TNM Stage I & II) 구강 편평세포암종의 초치료 실패

이현석,정한신,김태욱,손영익,백정환,Lee Hyun-Seok,Jeong Han-Sin,Kim Tae-Wook,Son Young-Ik,Baek Chung-Hwan 대한두경부종양학회 2005 대한두경부 종양학회지 Vol.21 No.1

Backgrounds and Objectives: Squamous cell carcinomas of the oral cavity(SCOC) in TNM stage I & II have relatively high chance to be cured compared to those in the advanced stage, but sometimes result in the treatment failure with poor prognosis. There have been few reports on the patterns of failure and the clinical courses for SCOC in stage I & II after the failure of initial treatment. This study is directed at identifying the clinical outcomes of stage I & II SCOC and the salvage rate after initial treatment and suggesting an optimal level of treatment by analyzing the patterns of failure. Material and Methods: The medical records of 36 patients with SCOC, initially diagnosed between 1995 and 2001 as TNM stage I & II were reviewed retrospectively. The patterns of failure, salvage treatment, clinical courses, and the survival of these subjects were analyzed. The minimum follow-up period of no-evidence of disease(NED) was 12 months with an average of 32.2 months. Results: Overall rate of the treatment failure in SCOC of stage I & II was 41. 7%(15/36 cases). Most of the treatment failure in the subjects with stage I tumors occurred in regional lymph node. Local failure was the most frequent form of failure in the subjects with stage II tumors after wide excision of primary tumor with elective neck dissection and/or radiation therapy. No significant correlation was noted between the safety margin and the local failure. Elective neck dissections in stage I & II SCOC had a tendency to reduce regional failure (p=0.055). The salvage rates at 24 months were 85.7% in stage I, and 37.5% in stage II. The 3-year survival rate after the failure of initial treatment was 55.0%. Conclusion: SCOC of stage I & II after the failure of initial treatment showed poor prognosis despite of the salvage treatments. This study implies that the elective neck dissections for regional lymph node should be required for SCOC of stage I & II to reduce the treatment failure.

고속도로 과적차량 단속체계의 법제 개선 방안

이현석,Lee, Hyeon-Seok 대한교통학회 2015 교통 기술과 정책 Vol.12 No.1

Effect of Fiber Surfce Modification by Electron Beam lrradiation on the Interfacial and Mechanical Properties of Henequen/Polypropylence Biocomposites

이현석,조동환,한성옥,금오공대 한국고분자학회 2006 한국고분자학회 학술대회 연구논문 초록집 Vol.2006 No.4

관광플랫폼 이용 중요속성에 따른 사용가치 및 지각된 희생과 재이용 의도 연구 - 신용카드사 관광플랫폼 서비스를 기준으로 -

이현석,윤유식,김미성 한국호텔리조트학회 2020 호텔리조트연구 Vol.19 No.4

The purpose of this study is to identify mechanisms that increase the intention of customers to reuse the tourism platform, after analyzing the satisfaction of customers with services offered by credit card companies. To this end, we analyzed how the use-value and sacrifice factors of the credit card company's tourism platform influenced customers' intention to reuse the service. We then identified the causal relationship between each variable. We also highlight the services that the credit card company's tourism platform should focus on to increase customer reuse intention. In order to empirically analyze this, we included a survey of credit card company tourism platform users, and analyzed the results of the survey by setting hypotheses and suggesting research models through operational definition.

재조직 선정기업 특성에 관한 연구

이현석,구정숙 한국산업경영학회 2010 經營硏究 Vol.25 No.2

This paper empirically analyzes financial characteristics between legal reorganization(liquidation of company and Vergleich) and private reorganization (workout), and between manufacturing firms and non-manufacturing firms from selection time point of reorganization to the seconde time. Samples are constituted with 62 firms of private reorganization and 103 firms of legal reorganization. We select the leverage ratio from financial institutes, profitability, firm’s size, the ratio of secured debt, negotiation power between borrower and lender, liquidity and the ratio of large stock holders as financial characteristic variable. Empirical results are tested by probit analysis, Fisher's Z-test and ANOVA. We find that All companies, manufacturing, non-manufacturing firms have the higher firms size to private reorganization firms. And the higher leverage ratio is preferred in legal reorganization firms. Leverage, ratio of secured debt, profitability and liquidity show different results according to the time point of reorganizations and whether manufacturing firms or not. 본 연구는 워크아웃에 의한 사적 재조직 기업과 회사정리나 화의제도와 같은 법적 재조직 기업 사이의 재무적 특성이 재조직 선정과 진행 시점 및 산업(제조업, 비제조업) 각각에서 차이가 있는지를 실증분석을 통해 살펴보고 있다. 표본기업은 1997년~2007년에 코스피 및 코스닥 기업 중 사적 재조직 62개사와 법적 재조직 103개사이며, 재무적 특성 변수로는 금융기관 부채비중, 수익성, 기업규모, 보증 회사채 비중, 채무자와 채권자 교섭력, 유동성, 최대주주 비중 등이다. 실증분석 방법으로는 ANOVA 및 Fisher의 Z검정, 프로빗 분석 방법 등을 사용하였다. 분석 결과 전체기업 및 제조업과 비제조업에서 재조직 직전 년과 1, 2차년 모두 기업규모가 클수록 사적 재조직이 보다 선호됨을 발견하였다. 전체기업에서 재조직 시점 모두 법적 재조직은 사적 재조직에 비해 부채비율이 클수록 선호됨을 또한 확인하였다. 부채비율과 보증회사채 비중, 수익성, 유동성 등의 변수는 산업 및 재조직 시점에 따라 다양한 결과를 보이고 있다.

공정거래법상 금지청구권 도입의 문제점과 선결과제

이현석 한국공정경쟁연합회 2010 경쟁저널 Vol.- No.152

Influence of Electron Beam lrradiation onto the Natural Fiber on the Interfacial Mechanica- and Thermal Properties of Kenaf/Kenaf/Unsaturated Polyester Bio-composites

이현석,조동환,한성옥 한국고분자학회 2007 한국고분자학회 학술대회 연구논문 초록집 Vol.2007 No.4