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

음악의 유무와 개인의 성향이 하체 근파워에 미치는 영향

이현석,김한샘,배경구,성정민,강현주 순천향대학교 기초과학연구소 2015 순천향자연과학연구 논문집 Vol.21 No.1,2

Music therapy is used in many settings, including schools, medicals, and physical and mental rehabilitation. This study examined the relationship between music preference and lower extremity power in college-aged students. A total of 19 healthy subjects (M=9, F=10) aged from 19-25 participated in this study. All subjects were measured in three different conditions while measuring their lower extremity power : 1) without listening to music; 2) listening to favorable music; 3) listening to unfavorable music. According to our data, there is a significant interaction between listening to favorable music and performance in the lower extremity power.

자트로파의 단간처리가 가지발생수 및 생존율에 미치는 영향

이현석,안찬훈,김철우,이재선 한국임학회 2009 한국임학회 정기학술발표논문집 Vol.2009 No.-

벼 생태형별 영양생장기 온도에 따른 출수반응 변화 분석

이현석,최경진,황운하,정재혁,정한용,윤종탁,안승현,이건휘 한국작물학회 2017 한국작물학회 학술발표대회 논문집 Vol.2017 No.-

말레이시아 Merdeka 118 Tower

이현석,박재홍,김경종,김성겸,이승엽 한국건축시공학회 2022 건축시공 Vol.22 No.2

Calorific Value Characteristics of Short Rotation Coppies Trees for Biomass Resourcification - Based on Salix gracilistyla -

이현석,이재선,안찬훈 경상대학교 농업생명과학연구원 2016 농업생명과학연구 Vol.50 No.6

As the short rotation coppices(SRC), Salix spp., poplar and yellow poplar, they demonstratefast growth and asexual propagation ability. Despite the rapid growth characteristics, for use astree biomass materials, calorific value has not been extensively studied. In this study, itinvestigated the calorific values belonging to Salix spp., poplar and yellow poplar with particularemphasis on S. gracilistyla., S. gracilistyla and S. caprea showed greater calorific values thanthose measured with other species(4,546.6 cal g-1 and 4,539.6 cal g-1 respectively). Calorificvalues were demonstrated to the higher content of xylem tissue. S. gracilistyla from Wonju,YW1-1 and WJ2-9 showed the higher calorific values than other groups and clones. The presentresults demonstrate higher calorific value and low ash content, and these will be selectedasappropriate species and clones for biomass production purpose.

Fabrication of omni-directional driving system using unconstrained steel ball

이현석,나영민,박태곤,차영택,박종규 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.1

An omni-directional driving system with one spherical wheel is proposed in this paper. This system can overcome the limitations ofexisting driving systems, such as structural limitations that reduce vertical, horizontal, and diagonal movements. The proposed drivingsystem is composed of two stepper motors, a steel ball covered by steel ball bearing, a counterweight to eliminate eccentricity, and ballplungers for balance. All parts of this structure are located at the same distance from the center of the system to place the center of gravityat the system center. The ball bearing was designed for even rotation and smooth directional changes of the spherical wheel using amodel similar to that in a computer mouse ball. Steel was selected for the ball bearing material to prevent slipping on the ground. Moreover,the steel ball is stable because of the support from the ball bearing. One of the stepping motors is used for driving the sphericalwheel. The other stepping motor enables movement in the desired direction by rotating on the central axis. The ATmega128 microcontrolleris used for controlling the two stepping motors. Driving experiments were executed in a variety of environments, confirming theperformance and validity of the omni-directional driving system.

Crystallization and Structural Relaxation behavior of Amorphous Ge-doped SbTe with Various Sb/Te Ratios (초)

이현석,정중현,이수연,이택성,오철,안형우,박영욱,정병기 대한금속재료학회 ( 구 대한금속학회 ) 2008 대한금속재료학회 학술대회 개요집 Vol.2008 No.1

무선 센서 네트워크에서 균등한 클러스터 밀도를 고려한 토큰 기반의 클러스터링 알고리즘

이현석,허정석,Lee, Hyun-Seok,Heo, Jeong-Seok 한국정보처리학회 2010 정보처리학회논문지 C : 정보통신,정보보안 Vol.17 No.3

무선 센서 네트워크에서 센서노드의 수명은 배터리에 의해 제한되므로 에너지는 가장 중요한 고려사항이다. 클러스터링은 네트워크의 에너지 소비를 효율적으로 관리하는데 사용되는 방법 중 하나이며, LEACH는 대표적인 클러스터링 알고리즘이다. LEACH는 센서 노드들의 에너지 소비를 공평하게 분산시키기 위해 에너지 소모적 기능을 하는 클러스터 헤드를 매 라운드마다 무작위로 순환시키는 방법을 사용하고 있다. 클러스터 헤드의 무작위 선정은 매 라운드 최적의 클러스터 헤드 수를 보장해주지 못한다. 그리고 밀도가 높은 클러스터에 위치한 클러스터 헤드는 과부하 상태가 된다. 본 논문에서는 클러스터 헤드의 수를 보장하기 위한 토큰 기반의 클러스터 헤드 선정 알고리즘과 균등한 밀도의 클러스터 형성을 위한 클러스터 선택 알고리즘을 제안한다. 시뮬레이션을 통하여 제안하는 알고리즘이 LEACH 보다 네트워크 수명이 9.3%정도 연장됨을 보여주었다. In wireless sensor networks, energy is the most important consideration because the lifetime of the sensor node is limited by battery. The clustering is the one of methods used to manage network energy consumption efficiently and LEACH(Low-Energy Adaptive Clustering Hierarchy) is one of the most famous clustering algorithms. LEACH utilizes randomized rotation of cluster-head to evenly distribute the energy load among the sensor nodes in the network. The random selection method of cluster-head does not guarantee the number of cluster-heads produced in each round to be equal to expected optimal value. And, the cluster head in a high-density cluster has an overload condition. In this paper, we proposed both a token based cluster-head selection algorithm for guarantee the number of cluster-heads and a cluster selection algorithm for uniform-density cluster. Through simulation, it is shown that the proposed algorithm improve the network lifetime about 9.3% better than LEACH.

RF Magnetron Sputtering을 이용하여 제작한 불용성 촉매전극의 해수전기분해 특성

이현석,김세기,석혜원,김진호,최헌진,정하익,Lee, Hyun-Seok,Kim, Sei-Ki,Seok, Hye-Won,Kim, Jin-Ho,Choi, Hun-Jin,Jung, Ha-Ik 한국재료학회 2012 한국재료학회지 Vol.22 No.2

Insoluble catalytic electrodes were fabricated by RF magnetron sputtering of Pt on Ti substrates and the performance of seawater electrolysis was compared in these electrodes to that is DSA electrodes. The Pt-sputtered insoluble catalytic electrodes were nearly 150 nm-thick with a roughness of $0.18{\mu}m$, which is 1/660 and 1/12 of these values for the DSA (dimensionally stable anodes) electrodes. The seawater electrolysis performance levels were determined through measurements of the NaOCl concentration, which was the main reaction product after electrolysis using artificial seawater. The NaOCl concentration after 2 h of electrolysis with artificial seawater, which has 3.5% NaCl normally, at current densities of 50, 80 and 140 mA/$cm^2$ were 0.76%, 1.06%, and 2.03%, respectively. A higher current density applied through the electrodes led to higher electrolysis efficiency. The efficiency reached nearly 58% in the Pt-sputtered samples after 2 h of electrolysis. The reaction efficiency of DSA showed higher values than that of the Pt-sputtered insoluble catalytic electrodes. One plausible reason for this is the higher specific surface area of the DSA electrodes; the surface cracks of the DSAs resulted in a higher specific surface area and higher reaction sites. Upon the electrolysis process, some Mg- and Ca-hydroxides, which were minor components in the artificial seawater, were deposited onto the surface of the electrodes, resulting in an increase in the electrical resistances of the electrodes. However, the extent of the increase ranged from 4% to 7% within an electrolysis time of 720 h.