플라이애시 부유선별 과정에서 교반속도와 공기주입량 변화에 따른 영향 연구

김민식,강헌찬,Kim, Min Sik,Kang, Heon Chan 한국자원리싸이클링학회 2018 資源 리싸이클링 Vol.27 No.1

플라이애시의 부유선별 과정에서 교반속도와 공기주입량과 같은 기계적 요소 변화에 따른 영향을 알아보고자 본 연구를 실시하였다. 본 연구에서는 미연탄소 함량이 약 3.4 ~ 3.7% 수준인 화력발전소 플라이애시를 사용하였다. 대표적인 부유선별의 선별 요소인 pH, 교반속도, 포수제 첨가량, 기포제 첨가량 변화에 따른 영향을 살펴보았을 때, Safflower oil을 포수제로 사용하여 첨가량을 800 g/ton, pH 7, 교반속도 1,200 rpm, 기포제 첨가량이 400 g/ton였을 때, 미연탄소 회수율과 미연탄소 함량이 각각 63%, 34%로 나타났다. 이 때 부상물 SEM/EDS 분석을 통해 알아본 결과, 구형의 플라이애시 미립자가 미연탄소 내에 고용되거나, 광액 내에 가라앉지 못하고 기포와 함께 부유함으로써 미연탄소의 함량을 낮추는 것으로 나타났다. 교반속도와 공기주입량과 같은 기계적 요소를 변화시킨 실험에서는 공기주입량 8L/min, 교반 속도 900 rpm에서 미연탄소 회수율 74%, 미연탄소 함량 67%인 것으로 나타났다. 이는 낮은 교반속도와 추가 공기주입으로 인하여 광액 내 와류의 강도가 낮아져, 미립의 플라이애시 입자가 미연탄소와 함께 부유되는 현상을 방지됨으로써, 미연탄소 회수율과 미연탄소 함량이 향상된 것으로 나타났다. 또한, 교반속도와 공기주입량을 각각 800 rpm, 6 L/min으로 설정하였을 때 미연탄소 회수율과 미연탄소 탄소함량이 각각 80%, 70%로 향상되어 가장 우수한 것으로 나타났다.

Electrical Properties of Eco-Friendly RuO₂-Based Thick-Film Resistors Containing CaO-ZnO-B₂O₃-Al₂O₃-SiO₂ 계 유리가 적용된 질화알루미늄 기판용 RuO₂계 친환경 후막저항의 전기적 특성

김민식,김형준,김형태,김동진,김영도,류성수,Kim, Min-Sik,Kim, Hyeong-Jun,Kim, Hyung-Tae,Kim, Dong-Jin,Kim, Young-Do,Ryu, Sung-Soo 한국세라믹학회 2010 한국세라믹학회지 Vol.47 No.5

The objective of this study is to prepare lead-free thick film resistor (TFR) paste compatible with AlN substrate for hybrid microelectronics. For this purpose, CaO-ZnO-$B_2O_3-Al_2O_3-SiO_2$ glass system was chosen as a sintering aid of $RuO_2$. The effects of the weight ratio of CaO to ZnO in glass composition, the glass content and the sintering temperature on the electrical properties of TFR were investigated. $RuO_2$ as a conductive and glass powder were dispersed in an organic binder to obtain printable paste and then thick-film was formed by screen printing, followed by sintering at the range between $750^{\circ}C$ and $900^{\circ}C$ for 10 min with a heating rate of $50^{\circ}C$/min in an ambient atmosphere. The addition of ZnO to glass composition and sintering at higher temperature resulted in increasing sheet resistance and decreasing temperature coefficient of resistance. Using $RuO_2$-based resistor paste containing 40 wt%glass of CaO-20.5%ZnO-25%$B_2O_3$-7%$Al_2O_3$-15%$SiO_2$ composition, it is possible to produce thick film resistor on AlN substrate with sheet resistance of $10.6\Omega/\spuare$ and the temperature coefficient of resistance of 702ppm/$^{\circ}C$ after sintering at $850^{\circ}C$.

국내외 ASP 시장동향과 전망

김민식,Kim, Min-Sik 한국정보통신집흥협회 2001 정보화사회 Vol.152 No.-

신갈나무와 굴참나무 수간류, 임내우의 pH, 전기전도도 및 음이온 변화

김민식,서문원,츠지오 에자키,전근우,Kim, Min-Sik,Seomun, Won,EZAKI, Tsugio,Chun, Kun-Woo 강원대학교 산림과학연구소 2000 Journal of Forest Science Vol.16 No.-

강원대학교 산림과학대학에서는 부속연습림의 주요 활엽수종인 신갈나무와 굴참나무의 pH, 전기전도도 및 음이온 농도를 1996년부터 측정하고 있으며, 1998년까지의 결과는 다음과 같다. 1. 임외우의 pH범위는 4.47~6.55, 평균값은 5.39였으며, 신갈나무와 굴참나무 임내우의 pH범위는 각각 4.07~6.25, 4.34~6.57, 평균값은 5.45와 5.62로 수종간의 차이는 크게 나타나지 않았다. 또한 신갈나무 수간류의 pH 범위는 4.08~6.13. 평균 5.17 였으며, 굴참나무 수간류의 pH 범위는 3.62~6.11, 평균 4.68로 임외우의 pH에 반듯이 비례하지는 않았다. 그러나 봄철이 낮고 상대적으로 여름과 가을철에는 높은 계절적 차이를 발견할 수 있었다. 2. 임외우의 EC범위는 $3.0{\sim}62.6{\mu}s/cm$로 평균값은 $18.8{\mu}s/cm$였으며, 신갈나무와 굴참나무 임내우의 EC범위는 각각 $5.4{\sim}85.0{\mu}s/cm$, $5.0{\sim}253.0{\mu}s/cm$. 평균값은 $25.1{\mu}s/cm$와 $31.2{\mu}s/cm$였다. 또한 신갈나무와 굴참나무 수간류의 EC범위는 각각 $9.5{\sim}500{\mu}s/cm$, $11.5{\sim}534.5{\mu}s/cm$로 평균값은 $81.8{\mu}s/cm$, $80.2{\mu}s/cm$였다. 즉 임외우의 EC는 계절에 상관없이 $20{\sim}30{\mu}s/cm$범위에서 일정한 값을 나타냈으나, 수간류의 EC는 3월~4월에 두 수종 모두 $100{\mu}s/cm$이상을, 그리고 여름철에는 $30{\mu}s/cm$ 내외의 값을 나타내었나, 10월과 11월에 다시 높아지는 계절에 따른 차이가 명확히 나타났다. 3. 임외우와 임내우의 $Cl^-$, $NO_3{^-}$ 및 $SO_4{^{2-}}$ 농도는 0~15ppm였으나, $PO_4{^{2-}}$농도는 임외우가 0.57ppm과 0.23ppm 2차례, 신갈나무에서 0.08ppm 1차례, 굴참나무에서 0.14ppm, 0.12ppm 및 1.19ppm으로 3차례가 각각 검출되었을 뿐이다. 또한 수간류의 $Cl^-$, $NO_3{^-}$, $SO_4{^{2-}}$ 및 $PO_4{^{2-}}$ 농도는 전체적으로 임외우보다 높게 나타났으며, 계절적인 차이가 뚜렷하였다. 그러나 $PO_4{^{2-}}$농도의 경우, 임외우와 임내우에서는 거의 발생하지 않았으나 신갈나무와 굴참나무에서 각각 0.08~31.99ppm, 0.06~12.28ppm, 평균값은 각각 3.22ppm, 1.93ppm으로 나타났다. The pH, EC and anion of stemflow in Quercus mongolica and Q. variabilis were surveyed and analyzed in order to examine the relationship between watershed conservation function and flood control function of forest in quality and quantity in the Experiment Forests. College of Forest Sciences, Kangwon National University. The results were as follows: 1. pH values of rainfall ranged from 4.47 to 6.55(average: 5.39), and pH values of throughfall ranged from 4.07 to 6.25(average 5.45) for Q. mongolica and from 4.34 to 6.57(average : 5.62) for Q. variabilis, and thus pH values were not different between these two species. Also, pH values of stemflow from Q. mongolica ranged from 4.08 to 6.13(average 5.17) and those of stemflow from Q. variabilis ranged from 3.62 to 6.11(average : 4.68), and pH values of rainfall gave little influence on pH values of stemflow. But, pH values of stemflow in Q. mongolica and Q. variabilis appeard significantly lower in spring and than those in summer and autumn. 2. EC of rainfall was $3.0{\sim}62.6{\mu}s/cm$(average: $18.8{\mu}s/cm$), and EC of throughfall was $5.4{\sim}85.0{\mu}s/cm$(average : $25.1{\mu}s/cm$) for Q. mongolica and $5.0{\sim}253.0{\mu}s/cm$(average : $31.2{\mu}s/cm$) for Q. variabilis. Also, EC of stemflow from Q. mongolica ranged from 9.5 to $500.0{\mu}s/cm$(average : $81.8{\mu}s/cm$) and that of stemflow from Q. variabilis ranged from 11.5 to $534.5{\mu}s/cm$(average : $80.2{\mu}s/cm$). Seasonal EC of rainfall had little variation in the range of 20 to $30{\mu}s/cm$: EC of stemflow showed more than $100{\mu}s/cm$ from March to April and about $30{\mu}s/cm$ in summer period. Seasonal EC of stemflow varied so much and appeared high again from October to November. 3. $Cl^-$, $NO_3{^-}$ and $SO_4{^{2- }}$ concentrations of rainfall and throughfall were from 1 to 15ppm. and $PO_4{^{2- }}$ concentrations showed 0.57ppm and 0.23ppm in rainfall, 0.08ppm in Q. mongolica and 0.14ppm, 0.12ppm and 1.19ppm in Q. variabilis. Also, $Cl^-$, $NO_3{^-}$ and $SO_4{^{2-}}$ concentrations of stemflow were relatively higher than rainfall, and showed differences among seasons. $PO_4{^{2-}}$ concentration of rainfall and throughfall were not possible to observe, but $PO_4{^{2-}}$ concentrations of stemflow ranged from 0.08 to 31.99ppm(average : 3.22ppm) for Q. mongolica and that of stemflow ranged from 0.06 to 12.28ppm(average : 1.93ppm) for Q. variabilis.

난분해성 산업폐수 처리를 위한 고도산화기술

김민식,이기명,이창하,Kim, Min Sik,Lee, Ki-Myeong,Lee, Changha 대한상하수도학회 2020 상하수도학회지 Vol.34 No.6

Industrial wastewater often contains a number of recalcitrant organic contaminants. These contaminants are hardly degradable by biological wastewater treatment processes, which requires a more powerful treatment method based on chemical oxidation. Advanced oxidation technology (AOT) has been extensively studied for the treatment of nonbiodegradable organics in water and wastewater. Among different AOTs developed up to date, ozonation and the Fenton process are the representative technologies that widely used in the field. Based on the traditional ozonation and the Fenton process, several modified processes have been also developed to accelerate the production of reactive radicals. This article reviews the chemistry of ozonation and the Fenton process as well as the cases of application of these two AOTs to industrial wastewater treatment. In addition, research needs to improve the cost efficiency of ozonation and the Fenton process were discussed.

러프 집합을 이용한 코스피 200 주가지수옵션 시장에서의 박스스프레드 전략 실증분석 및 거래 전략

김민식,오경주,Kim, Min-Sik,Oh, Kyong-Joo 한국데이터정보과학회 2011 한국데이터정보과학회지 Vol.22 No.1

Stock price index option market has various investment strategies that have been developed. Specially, arbitrage strategies are very important to be efficient in option market. The purpose of this study is to improve profit using rough set and Box spread by using past option trading data. Option trading data was based on an actual stock exchange market tick data ranging from 2001 to 2006. Validation process was carried out by transferring the tick data into one-minute intervals. Box spread arbitrage strategies is low risk but low profit. It can be accomplished by back-testing of the existing strategy of the past data and by using rough set, which limit the time line of dealing. This study can make more stable profits with lower risk if control the strategy that can produces a higher profit module compared to that of the same level of risk. 주가지수 옵션시장에는 많은 투자전략이 개발되어 있다. 그중 차익거래 전략은 시장이 효율성 유지측면에서 매우 중요한 역할을 하고 있다. 본 연구는 이러한 차익거래 전략 중 박스스프레드 전략을 적용하여 과거 옵션 데이터를 통해 사후 검증하고 러프 집합을 이용해 수익성을 향상시키고자 한다. 옵션 데이터는 2002년 1월부터 2006년 12월까지 실제 증권거래소에서 거래되었던 틱 데이터를 기반으로 하고 있으며 비주얼 베이직을 이용해 9시부터 오후 3시까지의 1분 마다의 종가인 1분봉으로 변형하여 분석을 하였다. 박스스프레드 전략은 낮은 위험, 낮은 이익 구조를 가지고 있다. 기존의 전략을 과거 데이터를 기반으로 백 테스팅 해보고 러프 집합을 이용하여 거래 진입 시점을 제한함으로써, 동일 위험 대비 좀 더 높은 수익구조를 만들어 낼 수 있는 전략을 구사한다면 낮은 위험으로 안정적 수익을 취할 수 있다.

편도암 절제술후 전완유리피판술을 이용한 연구개 결손부 재건의 기능적 결과

김민식,선동일,박해섭,조승호,제현순,Kim, Min-Sik,Sun, Dong-Il,Park, Hae-Sup,Cho, Seung-Ho,Jai, Hyeon-Soon 대한기관식도과학회 1999 大韓氣管食道科學會誌 Vol.5 No.2

Background and Objective : Soft palate plays a great role in function of speech and swallowing. Ablation of tonsil cancer results in multi-demensional defect including soft palate in most cases and restoration of the postoperative oral cavity function is a continuing surgical challenge. Although a variety of techniques are available, radial forearm free flap has been known as an effective method for these defect, which offers a thin, pliable, and relatively hairless skin, and a long vascular pedicle. The aim of the present study is to report the speech and swallowing function test results of our 5 consecutive radial forearm free flaps used for tonsil cancers. Materials and Methods : We reviewed the medical records of 5 patients who were offered intraoral reconstruction with a radial forearm free flap after ablative surgery for tonsil cancers, from Dec. 1997 to Oct. 1998, and analyzed the surgical methods, complications, and speech and swallowing function test results. We have examined with modified barium swallow to evaluate postoperative wallowing function and articulation and resonance test for speech. Results : The tumor sizes by TNM stage(AJCC, 1997) were T1(1), T2(2), and T4(3). The paddles of flaps were tailored in multilobed designs from oval shape to pentalobed design and in variable size from 24$cm^2$ to 108$cm^2$(average size = 78.4$cm^2$), according to the defect after ablation. This procedures resulted in satisfactory flap success and functional results all but 1 case of flap contracture in 2 postoperative week, achieved early oral diet until 16-57 postoperative day(average, 28 days) and social speech. The oropharyngeal defect including soft palate reconstruction with radial forearm free flap might be an excellent method for the maximal functional results, after ablative surgery of tonsil cancer that results in multidimensional defect.

이하선 적출에서의 변형적 안면 거상 절개법

김민식,선동일,노우영,조승호,Kim, Min-Sik,Sun, Dong-Il,Ro, Woo-Young,Cho, Seung-Ho 대한기관식도과학회 1999 大韓氣管食道科學會誌 Vol.5 No.2

Background and objectives : During the last century, various incisions for parotidectomy has introduced and among them, the modified Blair incision has been the one most commonly used. The modified facelift incision, in another hand, has only been introduced and applied recently for better aesthetic results, but also has been criticized for its potentially limited anterior exposure. The purpose of this study is to compare the modified facelift incision with the modified Blair incision in its indications, results and complications. Materials and methods : All parotidectomies done at Kang-nam St. Mary's Hospital for benign parotid masses from Jan. 1995 to Aug. 1998 were reviewed. They were then divided into 2 groups according to their surgical approach, and the parameters included age, gender, complications length of follow-ups, the aesthetic results and the pt's satisfaction. Results : There were no significant differences in the incidence of complications in both groups and the aesthetic results and patient's satisfaction were greater in the modified facelift group. Conclusion : The modified facelift incision provides improved aesthetic results in patients with benign parotid masses without the disadvantage of limited exposure and complications.

FRP Plate를 이용한 표면매입 보강에서 보강재 간격에 따른 부착성능 연구

김민식,서수연,권영순 한국구조물진단유지관리학회 2011 한국구조물진단학회 학술발표회논문집 Vol.2011 No.9

This study was conducted to analyze bond capacity of FRP Plates through experiment in case of Near Surface Mounted Retrofit (NSMR) for the wide concrete members such as floors or walls. The embedded interval of FRP Plates applied as main variables. Tests were planned in a direct tensile test method by fixing the FRP Plates of specimens with grips. As a results, it was found out that the longer the embedded interval of FRP plates was, the higher the tensile strength was. It was observed in those tests that if the interval of embedded FRP Plates reached more than 90㎜ in the specimen, FRP Plates showed sufficient strength without splitting fracture of concrete.

하인두 암종의 보존적 수술

김민식,Kim Min Sik 대한기관식도과학회 2004 大韓氣管食道科學會誌 Vol.10 No.1