반도체 웨이퍼 제조공정(製造工程) 중 발생불산(發生廢酸)으로부터 $Na_{2}SiF_6$ 및 초산의 회수(回收)에 관한 연구(硏究)

김현상,김주엽,이향숙,신창훈,김준영,배우근,안종관,Kim, Hyun-Sang,Kim, Ju-Yup,Lee, Hyang-Sook,Shin, Chang-Hoon,Kim, Jun-Young,Bae, Woo-Keun,Ahn, Jong-Kwan 한국자원리싸이클링학회 2008 資源 리싸이클링 Vol.17 No.5

반도체 웨이퍼 제조 공정 중 발생하는 질산, 불산, 초산으로 구성된 혼산을 재활용하기 위한 연구를 수행하였다 초기에 $NaNO_3$와 $Na_{2}SiO_3$를 사용하여 불산을 $Na_{2}SiF_6$로 침전시켜 회수하였고, 이 때 혼산 중 불산의 농도는 초기 110g/L에서 0.5g/L로 낮아져 불산 회수율은 99.5%였다. 불산회수 후 남은 혼산의 질산과 초산의 농도는 각각 498g/L, 265g/L였고, 이 혼산을 2단계 분별증류 법에 의해 분리 회수하였다. 1단계에서는 초산을 증류하여 질산과 분리해내고, 2단계에서는 증류된 초산 중 잔류하는 미량의 질산을 제거하여 순수 초산만을 회수하였다. 회수된 초산의 농도는 약 20%였고, 최종회수율은 약 87.5%이었다. We researched recycle of mixed waste acids including HF, $CH_{3}COOH$, $HNO_3$ produced during semiconductor wafer process. At first, we recovered HF in form of $Na_{2}SiF_6$ by precipitation using $NaNO_3$ and $Na_{2}SiO_3$. Concentration of HF was made down from 110 g/L, initial concectration, to 0.5 g/L and Recovery rate of HF was 99.5%. After recovery of HF, concentration of $HNO_3$ and $CH_{3}COOH$ is 498 g/L, 265 g/L respectively. From that mixed acid, we recovered $CH_{3}COOH$ using 2 stages of fractional distillation. In first stage, $CH_{3}COOH$ was distilled for separation from $HNO_3$. And in second stage, we recoverd refined $CH_{3}COOH$ by using fractional distillation for removing a little amount of $HNO_3$ in $CH_{3}COOH$ vapor. The concentration of recovered $CH_{3}COOH$ in second stage is 20% and finally recovery rate of $CH_{3}COOH$ is about 87.5%.

열교환장치의 구조 및 재질에 따른 열회수율과 파울링의 발생 특성

김현상,김용구,봉춘근,이명화,Kim, Hyun-Sang,Kim, Yong-Gu,Bong, Choon-Keun,Lee, Myong-Hwa 한국자원리싸이클링학회 2015 資源 리싸이클링 Vol.24 No.2

본 연구에서는 급수예열기 및 공기예열기 등의 열교환장치의 구조 및 재질에 따른 열회수율 및 파울링 발생량 특성에 대해 조사하였다. 열교환기는 석탄화력발전소에서 일반적으로 구성된 급수예열기와 공기예열기를 대상으로 하였고, 소형소각로를 제작하여 모사실험을 수행하였다. 24시간동안 미분탄을 연소하면서 파울링 발생 및 열회수율의 변화를 관찰하였는데, 급수예열기의 구조에 따른 파울링 발생량은 핀(FIN) 튜브형 > 튜브 연결형 > 파이프형 > 자동세정형의 순서로 발생량이 많았으며, 그에 따른 열회수율은 핀튜브형 > 자동세정형 > 파이프형 > 튜브연결형 순으로 높게 나타났다. 공기예열기의 경우에는 구조에 따라 핀(FIN)튜브형 > 핀(FIN)판형 > 파이프형 > 테프론 파이프형 > 세라믹 파이프형 순으로 파울링 발생량이 많았으며, 열회수율도 같은 순서로 높게 나타났다. 재질의 내구성, 내산성, 내열성 등을 고려하여 세라믹이나 테플론 코팅을 할 경우에는 파울링량을 감소시킬 수는 있으나, 열회수율이 낮게 나타나 비효율적이었다. We researched characteristics of heat recovery rate and fouling according to structures and materials in heat exchangers like water preheater and air preheater. Economizer and air preheater have used in thermal electric power plant. we made small incinerator and heat exchangers to carry out simulated experiment. We observed fouling formation and change of heat recovery rate, combusting powdered coal for 24 hr. In economizer, fin tube type had the largest amount of fouling formation, followed by tube line type > pipe type > auto washing type according to structures. As heat recovery rate, fin tube showed highest recovery rate, followed by auto washing type > pipe type > tube line type. In air preheater, fin tube type had the largest amount of fouling formation, followed by fin plate type > pipe type > pipe type coated by teflon > pipe type coated by ceramic according to structures. And then, heat recovery rate showed the same oder.

자전거 도로의 업그레이드를 위한 현황진단 및 개선방안 (한강 자전거길 사례분석)

김현상,전우훈,Kim, Hyeon-Sang,Jeon, U-Hun 한국도로학회 2011 한국도로학회지 Vol.13 No.4

방사선이용 산업현장을 가다

김현상,Kim, Hyeon-Sang 한국동위원소협회 2006 동위원소회보 Vol.21 No.3

기자수첩 - 허울좋은 기름값 정책

김현상,Kim, Hyeon-Sang 대한석유협회 2012 석유와 에너지 Vol.285 No.-

Comparison of metabolites in rumen fluid, urine, and feces of dairy cow from subacute ruminal acidosis model measured by proton nuclear magnetic resonance spectroscopy

김현상,이신자,엄준식,최유영,Jo Seong Uk,Kim Jaemin,Lee Sang Suk,김언태,Lee Sung Sill 아세아·태평양축산학회 2023 Animal Bioscience Vol.36 No.1

Objective: In this study, metabolites that changed in the rumen fluid, urine and feces of dairy cows fed different feed ratios were investigated. Methods: Eight Holstein cows were used in this study. Rumen fluid, urine, and feces were collected from the normal concentrate diet (NCD) (Italian ryegrass 80%: concentrate 20% in the total feed) and high concentrate diet (HCD) groups (20%: 80%) of dairy cows. Metabolite analysis was performed using proton nuclear magnetic resonance (NMR) identification, and statistical analysis was performed using Chenomx NMR software 8.4 and Metaboanalyst 4.0. Results: The two groups of rumen fluid and urine samples were separated, and samples from the same group were aggregated together. On the other hand, the feces samples were not separated and showed similar tendencies between the two groups. In total, 160, 177, and 188 metabolites were identified in the rumen fluid, urine, and feces, respectively. The differential metabolites with low and high concentrations were 15 and 49, 14 and 16, and 2 and 2 in the rumen fluid, urine, and feces samples, in the NCD group. Conclusion: As HCD is related to rumen microbial changes, research on different metabolites such as glucuronate, acetylsalicylate, histidine, and O-Acetylcarnitine, which are related to bacterial degradation and metabolism, will need to be carried out in future studies along with microbial analysis. In urine, the identified metabolites, such as gallate, syringate, and vanillate can provide insight into microbial, metabolic, and feed parameters that cause changes depending on the feed rate. Additionally, it is thought that they can be used as potential biomarkers for further research on subacute ruminal acidosis.

수계 내 ZnO 나노입자의 제거 및 생태독성 저감

김현상(Hyunsang Kim),김영훈(Younghun Kim),김영희(Younghee Kim),이상구(Sangku Lee) 한국청정기술학회 2016 청정기술 Vol.22 No.2

화장품이나 타이어에 주로 사용되는 ZnO 나노입자에 대한 나노위해성 문제가 대두되고 있다. 이에 본 연구에서는 수계상에 존재하는 ZnO 나노입자에 대한 제거 및 생물학적 독성평가를 실시하였다. 송사리(O. Latipes) 수정란을 이용한 단기 노출평가에서는 5 mg L<SUP>-1</SUP>에서는 일부 개체에서 기형이 관찰되었고, 10 mg L<SUP>-1</SUP>에서 성장지연에 의한 부화율저감이 관찰되었다. 이러한 결과를 바탕으로 ZnO 나노입자가 수생생물종에게 독성을 보인다는 것을 확인하고, 이를 제거하기 위한 방법인 침전법을 제안하였다. Na₂S와 Na₂HPO₄를 이용하여 ZnO를 ZnS와 Zn₃(PO₄)₂로 전환시켜 침전시켰으며, 이들의 침전에 의한 제거율은 거의 100%에 이르렀다. 또한 해당 침전물 대한 물벼룩(D. magna) 급성독성 평가에서 어떠한 독성 영향도 찾지 못하였다. 이는 ZnO의 황 및 인처리를 통한 변환이 독성 감소에 효과적이었음을 나타낸다. The nanotoxicity of ZnO nanoparticles used in cosmetics and tire industry is one of emerged issues. Herein, the removal of ZnO nanoparticles dispersed in aqueous phase and its ecotoxicity were investigated. In the short-term exposure for fertilized eggs (O. latipes), the deformity was observed at 5 mg L<SUP>-1</SUP> of ZnO nanoparticles in some individuals and delayed hatching of eggs by retarded growth was observed at 10 mg L<SUP>-1</SUP> of ZnO nanoparticles. This result show that ZnO nanoparticles have cytotoxic effect to the organisms lived in water phase. Therefore, herein, the removal of ZnO nanoparticles in aqueous phase by chemical precipitation was investigated. After addition of Na₂S and Na₂HPO₄, the precipitated ZnO was transformed to ZnS and Zn₃(PO₄)₂ particles, respectively. The removal efficiency of ZnO was reached to almost 100% for two cases. In addition, the toxicity tests about ZnS and Zn₃(PO₄)₂ particles showed no acute toxicity for D. magna. This implies that transformation of ZnO to ZnS and Zn₃(PO4)₂ particles with very low ionization constant might decrease effectively the toxicity of ZnO.

철골 스마트구조 시스템의 구조적 거동 제어에 관한 연구 : 횡방향 하중을 중심으로

김현상(Kim, Hyun-Sang),장종문(Jang, Jong-Moon),조재덕(Cho, Jae-Duck),안형준(Ahn, Hyung-Joon) 한국구조물진단유지관리학회 2009 한국구조물진단학회 학술발표회논문집 Vol.2009 No.1

Computer's programs for a structure design apply simplified and generalized conditions. Accordingly, it can't make accurate explanation about a behavior of the real-living structure. In order to overcome these problems, the Smart Structure is introduced. In addition, the effective real-time management system applied information technologies(IT) and web-based databases has been increasing steadily. Therefore, this research establishes Structural Health Monitooring System(SHM) and verifies a behavior of the real-living structure via an experiment. As a result of this research will prepare a foundation of the web-based SHM and the Smart Structure.

군단위 농촌지역의 스포츠이벤트에서 서비스품질 만족이 지역 이미지와 재방문의사에 미치는 영향

김현상(Hyun Sang Kim),박덕병(Duk Byeong Park),김성록(Sung Rok Kim) 한국농촌지도학회 2017 농촌지도와 개발 Vol.24 No.2

The service quality and image are a central factor in understanding tourists destination choice. Existing literature suggests that sport event and destination image could interact to influence tourism behaviours. The purpose of this study was to identify the factors influencing local im age and re-visit intention in the 68th Chungcheongnam-do Provincial Sport Event held in Yesan city. The results of the study are as follows; First, as a result of factor analysis on the satisfaction with the sports event composed of 17 items, three factors were categorized, which were ‘event management’, ‘event facility’ and ‘supporting facilities’. Second, satisfaction with local event had a positive effect on local image. Especially, satisfaction with event management had greater effect on local im age than event facilities and supporting facilities. Third, as satisfaction with local event had positive effect on re-visitation intention, satisfaction with sports event had positive effect on the success of the sport event itself and re-visitation in tention for the region. Fourth, as local im age had a positive effect on re-visitation intention, strategic approaches to linking factors of tourism are required to attract visitors in addition to sports events.

연속류도로 합류영향구간 속도-밀도 상관관계 분석

김현상(Kim Hyun Sang),도철웅(Doh Techeol Woong) 대한토목학회 2009 대한토목학회논문집 D Vol.29 No.4D

A연속류도로는 교통량-속도-밀도 간에 상호 밀접한 관계가 있기 때문에 연결로교통류가 본선에 합류하게 되면 속도나 밀도가 변할 뿐만 아니라 이들 간의 상관관계를 나타내는 모형식도 달라진다. 따라서, 본 연구는 합류영향권역에서 시공간적으로 연속된 교통자료를 이용하여 속도-밀도 변수간의 상관관계 변화구간을 파악하고, 구간별 변화내용을 분석하였다. 분석결과, 상류 및 합류구간에서는 “Underwood”모형의 지수형태를 보이며, 합류구간을 통과한 하류구간에서는 “Greenshields”모형의 직선형태를 나타내었다. 속도-밀도 상관관계가 변화된 하류변화구간은 연결로와 접속한 3차로의 합류 종점부를 기점으로 하류 100m~500m 범위에서 내측차로로 갈수록 점차 하류방향으로 이동하는 현상을 보였다. 또한, 상류구간, 합류구간, 하류변화구간은 속도밀도 모형에서 자유속도(상수)와 혼잡밀도에 대한 자유속도비(기울기)가 통계적으로 서로 다른 이질적인 교통류로 나타났다. Uninterrupted facility - since there is a close relationship between traffic volume, speed and density -, when a ramp traffic flow merges into the main line, will change the traffic speed or density, and the corresponding correlational model equation will be changed. Thus, this study, using time and space-series traffic data on areas under the influence of such a merging, identified sections which changed the correlation between speed and density variables, and examined such changes. As a result, the upstream and merging sections showed the "Underwood"-shaped exponent, and the downstream after passing the merging section showed a straight line "Greenshields" model. The downstream section which changed the correlation between speed and density showed a gradual downstream movement phenomenon within 100 m-500 m from the end of the third lane linking with the ramp, as the traffic approached the inner lanes. Also, the upstream section, merging section, and downstream section involving a change showed heterogeneous traffic flows which, in the speed-density model, have a statistically different free flow speed (constant) and a different ratio of free flow speed to jam density (gradient).