자동차(自動車) 폐촉매(廢觸媒)의 침출액(浸出液)으로부터 시멘테이션에 의한 백금족(白金族) 금속(金屬)의 회수(回收)

김민석,김병수,김은영,김수경,류재욱,이재천,Kim, Min-Seuk,Kim, Byung-Su,Kim, Eun-Young,Kim, Soo-Kyung,Ryu, Jae-Wook,Lee, Jae-Chun 한국자원리싸이클링학회 2011 資源 리싸이클링 Vol.20 No.4

금속분말을 환원제로 사용하는 시멘테이션에 의하여 자동차 폐촉매의 침출액과 침출잔사의 세척액으로부터 백금족 금속을 환원 석출시켜 회수하는 연구를 수행하였다. 환원제로 사용한 알루미늄, 마그네슘 그리고 아연이 백금족 금속의 시멘테이션에 미치는 영향을 조사하였으며 알루미늄을 최적 환원제로 선정하였다. 침출액에 19.3 당량의 알루미늄을 첨가하고 $50{\sim}60^{\circ}C$에서 10분간 시멘테이션을 행하였을 때 백금, 팔라듐, 로듐의 환원석출율은 각각 99.3%, 99.4%, 90.2% 정도 이었다. 또한 세척액에 알루미늄을 45 당량 투입한 후 시멘터이션 반응을 통해 백금, 팔라륨, 로듐을 각각 97%, 97%, 90% 회수할 수 있었다. 그리고 회수한 환원석출물의 금속불순물들을 질산침출로 제거함으로써 백금족 금속의 품위를 약 10% 정도 향상시킬 수 있었다. The recovery of platinum group metals (PGMs) from the leach solution of spent auto-catalyst and the wash solution of the leach residue was investigated in the laboratory scale experiments by the cementation process using metal powders as the reductant. In this study, the effect of Al, Mg and Zn powders on the cementation process was particularly examined. Aluminum powder was selected as the most suitable reductant for the cementation of PGMs. At the cementation time of 10 minute under the aluminium stoichimetric amount of 19.3 and the reaction temperature of $50{\sim}60^{\circ}C$, the recovery of platinum group metals from the leach solution of the spent auto-catalyst was found to be 99.3%, 99.4%, 90.2% for Pt, Pd and Rh, respectively. Under the same conditions with the aluminium stoichimetric amount of 45, the recovery of platinum group metals from the wash solution of the leach residue of spent catalyst was observed to be 97%, 97% and 90% for Pt, Pd and Rh, respectively. In addition, it was possible to upgrade the platinum group metals in the precipitates obtained from the cementation process by about 10% through the removal of metal impurities by the nitric acid leaching at ambient temperature.

복시환자의 임상양상

김민석,최진,김정훈,김재석,이주화,Min Seok Kim,Jin Choi,Jung Hoon Kim,Jae Suk Kim,Joo Hwa Lee 대한안과학회 2013 대한안과학회지 Vol.54 No.11

Purpose: To evaluate the clinical features, causes and outcomes of patients with diplopia. Methods: All patients presenting with diplopia from October 2010 to March 2012 and followed up for more than 3 months were retrospectively investigated. Results: During the study period, 59 patients with diplopia were identified. There were 42 males and 17 females with an average age of 50 years. Binocular diplopia accounted for 54 cases (92%) and 5 cases (8%) had monocular diplopia. Cranial nerve palsies were the most common cause of binocular diplopia (28 cases, 52%). Within the cranial nerve palsies group, 14 cases (50%) were accompanied by hypertension or diabetes mellitus. Binocular diplopia spontaneously resolved in 35 cases (65%) by 3 months rising to 41 cases (76%) by 7 months. Thirteen (93%) out of 14 cases of cranial nerve palsies with hypertension or diabetes resolved spontaneously by 3 months. Conclusions: Binocular diplopia was caused most commonly by cranial nerve palsy and resolved after 3 months in 65% of patients. A spontaneous recovery from diplopia was observed after 3 months in 93% of patients with cranial nerve palsies and microvascular disease such as hypertension or diabetes. Therefore, the initial observation without additional treatment would be sufficient in these patients. J Korean Ophthalmol Soc 2013;54(11):1772-1777

실리콘 웨이퍼 에칭공정으로부터 발생(發生)된 폐산(廢酸)을 이용(利用)한 스테인리스 스틸의 산세거동(酸洗擧動) 연구(硏究)

김민석,안종관,김홍인,김주엽,안재우,Kim, Min-Seuk,Ahn, Jong-Gwan,Kim, Hong-In,Kim, Ju-Yup,Ahn, Jae-Woo 한국자원리싸이클링학회 2008 資源 리싸이클링 Vol.17 No.2

실리콘 웨이퍼 에칭공정에서 발생하는 폐산을 스테인리스 스틸 산세공정에서 재활용하고자 이를 이용한 산세 거동을 조사하였다. 폐산 원액은 $19.6g/L^{-1}$ 실리콘을 함유한 불산, 질산 및 초산의 혼산이었으며 침전법에 의한 실리콘 제거 전후 폐산들을 이용하여 304 스테인레스 스틸 표면 산화막의 제거 시 측정된 open circuit potential(OCP) 변화 거동은 매우 상이하였다. 폐산 원액을 사용한 경우에는 OCP가 높고 연속적인 변화를 보이는데 비하여 실리콘 제거 공정에서 얻어진 용액의 경우에는 불연속적인 OCP변화와 전위요동현상이 나타났다. 이러한 거동의 차이는 표면 부동태막의 형성 및 제거와 공식이 발생하는 정도의 차이에 기인하는 것으로 생각되며, 실리콘 제거 공정에서 산도가 낮아진 폐산에서 산화막 제거속도가 높고 공식발생이 현저하였다. 산세 후 시료의 표면 광택도에 가장 큰 영향을 주는 것은 산세 온도였으며, 산세온도가 높아질수록 표면 광택도는 감소하였다. 동일 산세 조건에서는 폐산 원액을 사용한 경우가 실리콘을 제거공정으로부터 얻어진 용액을 사용한 경우보다 광택도가 높았다. Pickling of oxidized 304 stainless steel has been investigated using rotating disk electrode in waste acid solutions generated from the etching process of silicon wafer in order to recycle them. The waste acid solution contained acetic, nitric, hydrofluoric acids, and silicon of $19.6g/L^{-1}$. Electrochemical behavior during the pickling was distinctively different between the original and silicon-removed acid solutions. Open circuit potential was continuously changed in the original solution, while it was discontinuously changed and fluctuated in the silicon-removed solution. Fast and abrupt removal of surface oxide layer with severe pitting was observed in the silicon-removed solution. It was found that solution temperature had the most influential effect on glossiness. Surface glossiness after pickling was decreased with solution temperature. At the same condition, the glossiness was higher in the original solution than in the silicon-removed solution.

전해생성(電解生成)된 염소(鹽素)에 의한 폐인쇄회로기판(廢印刷會路基板)으로부터 동(銅)의 침출(浸出)

김민석,이재천,정진기,김병수,김은영,Kim, Min-Seuk,Lee, Jae-Chun,Jeong, Jin-Ki,Kim, Byung-Su,Kim, Eun-Young 한국자원리싸이클링학회 2005 資源 리싸이클링 Vol.14 No.5

염산용액에서 전해생성 된 염소를 이용하여 폐프린터의 인쇄회로기판으로부터 동을 침출하는 연구를 수행하였다. 폐인쇄회로기판을 분쇄한 다음 입자크기가 $0.6{\sim}1.2mm$인 비자성 성분을 선별하여 침출실험을 행하였다. 비자성 분쇄물 중 금속성분의 평균함량은 45wt%이었으며, 동이 금속성분의 83.6wt% 이었다. 1 M 염산용액에서 전해생성된 염소에 의한 동의 침출반응은 전류밀도와 교반속도에 크게 영향을 받았다. 염산농도: 1 M, 전류밀도: $20mA/cm^2$, 침출온도: $50^{\circ}C$, 침출시간: 180분, 교반속도: 600rpm의 침출조건에서 동의 침출율은 98%로서 침출액에서 농도는 3.69g/l 해당하였다. 동의 침출반응에 대한 전해생성 된 염소의 이용율은 교반속도가 높고 인가전류밀도가 낮을 수록 높았다. 또한 침출반응 초기에는 알루미늄, 납, 주석 등의 기타금속 성분의 침출이 활발하고 동의 침출반응은 억제되었다. Electro-generated chlorine leaching of waste printed circuit boards was investigated in hydrochloric acid solutions. Non-magnetic component of $0.6{\sim}1.2mm$ was prepared by grinding, magnetic separation, and sieving. The non-magnetic component of pulverized printed circuit board contained about 45% of metal component, in which copper was about 83.6%. The leaching rate of copper was greatly affected by current density and agitation speed. The leaching of copper up to 98% was achieved at $20mA/cm^2$, $50^{\circ}C$, 180 minutes, and 600 rpm in 1M HCl solutions. Increasing agitation and lowering current density enhanced utilization efficiency of electro-generated chlorine. Leaching of copper was suppressed at the initial stage, while the minor metal elements, such as aluminum, lead, and tin, were dominantly leached out.

폐의 경흉 세침흡인 세포검사

김민석,박인애,박선후,박성신,김활웅,문경철,김영아,이혜승,박기화,서정욱,이현순,함의근,Kim, Min-Suk,Park, In-Ae,Park, Sun-Hoo,Park, Sung-Shin,Kim, Hwal-Wong,Moon, Kyung-Chul,Kim, Young-Ah,Lee, Hye-Seung,Park, Ki-Wha,Seo, Jeoug-Wook,Lee, Hy 대한세포병리학회 1999 대한세포병리학회지 Vol.10 No.1

The authors analysed 2,653 cases of transthoracic fine needle aspiration cytology of the lung to evaluate the diagnostic accuracy and its limitation. A comparison was made between the original cytologic and the final histologic diagnoses on 1,149 cases from 1,074 patients. A diagnosis of malignancy was established in 38.3% benign in 48.1%, atypical lesion in 2.3%, and inadequate one in 11.9% of the cases. Statistical data on cytologic diagnoses were as follows; specificity 98.9%: sensitivity of procedure, 76.8%: sensitivity of diagnosis, 95.5%: false positive 5 cases: false negative 18 cases: predictive value for malignancy, 98.8%: predictive value for benign lesion, 79.5%: overall diagnostic efficiency, 87.5%: typing accuracy in malignant tumor, 80%.

소유역에서의 토사유출 산정을 위한 GeoWEPP model과 USLE의 비교.적용 연구 - 이천시 단월동 유역을 사례로

김민석,김진관,양동윤,Kim, Min-Seok,Kim, Jin-Kwan,Yang, Dong-Yoon 대한자원환경지질학회 2007 자원환경지질 Vol.40 No.1

GIS와 연계시켜 만든 분산형 모델의 대표적인 경험식인 USLE model과 물리학기반의 GeoWEPP model을 경기도 이천시에 위치한 소유역에 적용하여 2004년 1월에서 2005년 1월까지 1년간의 토사유출량을 비교하였다. 연구기간동안의 유출된 토사량은 실제관측결과 270.54 ton, USLE 모델 적용 시 358.1 ton, 그리고 GeoWEPP 모델 적용 시 283.30 ton으로 각각 산출되었다. 각각의 모델을 적용한 산출량은 실제 산출량보다 과대하게 산출되었으며, 산출결과만을 볼 때, GeoWEPP 모델을 적용한 토사유출량이 USLE 적용 산출량 보다 관측량에 더 근사한 산출량을 보였다. 모델 적용 산출량이 과대산출 된 원인으로는 실험웨어를 월류하여 빠져나간 부유물에 대한 양이 포함되지 않았기 때문으로 판단된다. The empirical USLE and the physically-based GeoWEPP which were distributed model linked with GIS (Geographical Information System) were applied to small natural catchment located in Icheon-si, Gyeonggi-do, South Korea. The results using by two models were total sediment yield from study catchment between January, 2004 and January, 2005. During the study period, the observed total sediment yield was 270.54 ton and the total sediment yield computed by USLE and GeoWEPP model were 358.1 ton and 283.30 ton, respectively. Each of results computed by USLE and GeoWEPP overestimated more than the observed total sediment yield, but, based on the results, the total sediment yield computed by GeoWEPP approximated to the observed result. We suggest that the reason why the total sediment yield using by models overestimated was that computed amounts by two models did not contain the amount of suspended sediment flowed over the weir.

강우의 시간해상도와 자료기간에 따른 설계홍수량의 변동성

김민석,이정환,문영일,Kim, Min-Seok,Lee, Jung-Hwan,Moon, Young-Il 한국수자원학회 2018 한국수자원학회논문집 Vol.51 No.7

대부분의 수문분석은 시 단위 강우를 기반으로 확률강우량과 강우시간분포를 산정하고, 확률강우량과 강우시간분포의 자료기간을 달리 적용하는 방법으로 강우-유출분석을 수행하고 있다. 본 연구에서는 자료형태(시 단위와 분 단위 강우자료)와 확률강우량과 강우시간분포의 다른 자료기간 적용에 따른 설계홍수량 변화를 정량화 하고자, 자료형태와 자료기간에 따라 지점빈도해석을 통한 확률강우량 산정과 Huff의 4분위 방법을 통한 강우시간분포를 산정하였다. 또한, 확률강우량과 설계강우 시간분포의 자료기간을 달리 적용한 강우-유출분석으로 설계홍수량 변동분석을 실시하였다. 분석결과, 자료형태에서는 분 단위 강우가 시 단위 강우보다 더욱 정확하고 효과적인 강우분석을 수행할 수 있는 것으로 나타났으며, 확률 강우량과 강우시간분포의 다른 자료기간을 적용하여 산정된 설계홍수량의 차 보다 자료형식에 따른 설계홍수량 결과가 보다 큰 차이를 보이는 것으로 나타났다. 이는 향후 분 단위 강우를 활용한 수문분석에 크게 기여할 것으로 판단된다. Most hydrological analysis such as probability rainfall and rainfall time distributions have typically carried out based on hourly rainfall and rainfall - runoff analysis have carried out by applying different periods of rainfall time distribution and probability rainfall. In this study, to quantify the change of design flood due to the data type (hourly and minutely rainfall data) and the probability rainfall and application of different data period to the rainfall time distribution, probability rainfall is calculated by point frequency analysis according to data type and period and rainfall time distribution was calculated by Huff's quartile distributions. In addition, the change analysis of design flood was carried out by rainfall - runoff analysis applying different data periods of design rainfall time distribution. and probability rainfall. As a result, rainfall analysis using minute rainfall data was more accurate and effective than using hourly rainfall data. And the design flood calculated by applying different data period of rainfall time distribution and probability rainfall made a large difference than by applying different data type. It is expected that this will contribute to the hydrological analysis using minutely rainfall.

유전 알고리즘을 이용한 Mn⁴⁺ 활성 적색 형광체 탐색

김민석,박운배,Kim, Minseuk,Park, Woon Bae 한국재료학회 2017 한국재료학회지 Vol.27 No.6

In the construction of a white LED, the region of the red emission is a very important factor. Red light emitting materials play an important role in improving the color rendering index of commercial lighting. These materials also increase the color gamut of display products. Therefore, the development of novel phosphors with red emission and the study of color tuning are actively underway to improve product quality. In the present study, heuristic algorithms were used to search for phosphors capable of increasing the color rendering index and color gamut. Using a heuristic algorithm, the phosphors that were identified were $SrGe_4O_9:Mn^{4+}$ and $BaGe_4O_9:Mn^{4+}$. Emission spectra study confirmed that these phosphors emit light in the deep red wavelength region, which can fulfill the requirement for the improvement in color rendering index and color gamut for a white LED.

Next Generation Sequencing을 통한 미생물 군집 분석의 축산분야 활용

김민석,백열창,오영균,Kim, Minseok,Baek, Youlchang,Oh, Young Kyoon 한국축산환경학회 2015 한국축산시설환경학회지 Vol.21 No.3

The objective of this study was to review application of next-generation sequencing (NGS) to investigate microbiome in the livestock sector. Since the 16S rRNA gene is used as a phylogenetic marker, unculturable members of microbiome in nature or managed environments have been investigated using the NGS technique based on 16S rRNA genes. However, few NGS studies have been conducted to investigate microbiome in the livestock sector. The 16S rRNA gene sequences obtained from NGS are classified to microbial taxa against the 16S rRNA gene reference database such as RDP, Greengenes and Silva databases. The sequences also are clustered into species-level OTUs at 97% sequence similarity. Microbiome similarity among treatment groups is visualized using principal coordinates analysis, while microbiome shared among treatment groups is visualized using a venn diagram. The use of the NGS technique will contribute to elucidating roles of microbiome in the livestock sector.

심층신경망 구조에 따른 구개인두부전증 환자 음성 인식 향상 연구

김민석,정재희,정보경,윤기무,배아라,김우일,Kim, Min-seok,Jung, Jae-hee,Jung, Bo-kyung,Yoon, Ki-mu,Bae, Ara,Kim, Wooil 한국음향학회 2019 韓國音響學會誌 Vol.38 No.6

본 논문에서는 구개인두부전증(VeloPharyngeal Insufficiency, VPI) 환자의 음성을 효과적으로 인식하기 위해 컨볼루션 신경망 (Convolutional Neural Network, CNN), 장단기 모델(Long Short Term Memory, LSTM) 구조 신경망을 은닉 마르코프 모델(Hidden Markov Model, HMM)과 결합한 하이브리드 구조의 음성 인식 시스템을 구축하고 모델 적응 기법을 적용하여, 기존 Gaussian Mixture Model(GMM-HMM), 완전 연결형 Deep Neural Network(DNN-HMM) 기반의 음성 인식 시스템과 성능을 비교한다. 정상인 화자가 PBW452단어를 발화한 데이터를 이용하여 초기 모델을 학습하고 정상인 화자의 VPI 모의 음성을 이용하여 화자 적응의 사전 모델을 생성한 후에 VPI 환자들의 음성으로 추가 적응 학습을 진행한다. VPI환자의 화자 적응 시에 CNN-HMM 기반 모델에서는 일부층만 적응 학습하고, LSTM-HMM 기반 모델의 경우에는 드롭 아웃 규제기법을 적용하여 성능을 관찰한 결과 기존 완전 연결형 DNN-HMM 인식기보다 3.68 % 향상된 음성 인식 성능을 나타낸다. 이러한 결과는 본 논문에서 제안하는 LSTM-HMM 기반의 하이브리드 음성 인식 기법이 많은 데이터를 확보하기 어려운 VPI 환자 음성에 대해 보다 향상된 인식률의 음성 인식 시스템을 구축하는데 효과적임을 입증한다. This paper proposes speech recognition systems employing Convolutional Neural Network (CNN) and Long Short Term Memory (LSTM) structures combined with Hidden Markov Moldel (HMM) to effectively recognize the speech of VeloPharyngeal Insufficiency (VPI) patients, and compares the recognition performance of the systems to the Gaussian Mixture Model (GMM-HMM) and fully-connected Deep Neural Network (DNNHMM) based speech recognition systems. In this paper, the initial model is trained using normal speakers' speech and simulated VPI speech is used for generating a prior model for speaker adaptation. For VPI speaker adaptation, selected layers are trained in the CNN-HMM based model, and dropout regulatory technique is applied in the LSTM-HMM based model, showing 3.68 % improvement in recognition accuracy. The experimental results demonstrate that the proposed LSTM-HMM-based speech recognition system is effective for VPI speech with small-sized speech data, compared to conventional GMM-HMM and fully-connected DNN-HMM system.