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공정 변수에 따른 PECVD 질화규소 박막 특성에 관한 연구
남철우,우성일,김용태 ( Chul Woo Nam,Seong Ihl Woo,Yong Tae Kim ) 한국화학공학회 1991 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.29 No.3
PECVD silicon nitride film was deposited on P-type (100) silicon wafer in a parallel plate type reactor. The effect of different process parameters such as substrate temperature, RF power, and feed gas composition on the properties of silicon nitride layer was studied. Hydrogen content of nitride film was strongly influenced by substrate temperature and decreased with increasing substrate temperature. RF power influenced the type of bond configuration in the film. Si-H bond was dominant at the RF power lower than 40 W, while N-H bond became dominant at the RF power higher than 40 W. Etch rate in buffered HF solution was increased with the increment of hydrogen content in the film. The films deposited in N₂ diluent showed hydrogen content and etch rate higher than those deposited in H₂ diluent. Interface charge density decreased as the flow rate of ammonia increased.
교과교육 사조의 고찰에 따라 새로 권장되는 교수학습방법
남철우(Chul Woo Nam) 한국초등과학교육학회 1999 초등과학교육 Vol.18 No.1
This paper describes some major trends in primary and secondary education now. It is a selective views of significant topics with important implication for the future. These trends are summarized as follows, after examining historical development of Teaching-learning Methodology in primary and secondary education. 1. Education is seen as part of interdisciplinary world; emphasis is on relating education to the students` world, which is not compartmentalized. 2. Emphasizing students` individual growth with their own goal of lives. 3. Open-education with variable contents and purposes of education. 4. Education for all from that for some. 5. Consructivist based from behavior based. 6. Cooperative learning, peer tutoring, group projects. 7. Authentic assessment; assessment integrated with instruction. 8. The teacher is a facilitator of learning and a learner as well; students are learners and teachers in some situations; networks emerge instead of one-way forms or communication. 9. Spiral curriculum from single exposure.
STS 교수-학습이 초등학교 과학적 태도 교육에 미치는 효과
남철우 ( Chul Woo Nam ),최춘호 ( Chun Ho Choi ),김정길 ( Jeong Kil Kim ),김석중 ( Suck Joong Kim ),송판섭 ( Pan Sup Song ),한광래 ( Kwang Iea Han ),최도성 ( Do Sung Choi ) 한국초등과학교육학회 2002 초등과학교육 Vol.21 No.2
This study examined the effect on the education of scientific attitude in the process of primary school education by application of STS teaching-learning method with an unit of 6th grade in primary school environmental pollution and nature conservation. The attitude relating science education, on the other side, is classified into 4 parts; attitude for science, social meaning of science, attitude for science subject and scientific attitude. The study of sexual difference on the above points was examined too. The results was taken as follows. 1. STS Teaching-learning method gives positive effect of the education of scientific attitude more than traditional teaching method, especially on the point of the attitude of science lesson and scientific attitude. 2. STS education has an great influence on the social meaning of the scientific attitude relating science education; investment in science, relation with society, solving social problem, contribution to development of society and technology. 3. STS teaching-learning is thought to be the learning that is more effective for boy than girl. In conclusion The STS Teaching-learning method is preferable in order to increase the scientific attitude of the elementary school students.
용매추출-전해채취법에 의한 망간단괴 매트상 모의 침출용액으로부터 코발트 회수
김현호,남철우,박경호,윤호성,김민석,김철주,박상운,Kim, Hyun-Ho,Nam, Chul-Woo,Park, Kyung-Ho,Yoon, Ho-Sung,Kim, Min-Seuk,Kim, Chul-Joo,Park, Sang-Woon 한국자원리싸이클링학회 2016 資源 리싸이클링 Vol.25 No.2
망간단괴 매트상 모의 침출용액에서 구리 용매추출과 수산화 침전법에 의해 구리와 철이 제거 된 용액(Co 1.91 g/L, Ni 14.65 g/L)으로부터 용매추출-전해채취 연속공정을 통해 코발트를 분리, 회수를 위한 규모확대 실험(망간단괴 기준 380 kg/day)을 수행하였다. 용매추출의 경우 추출제로는 NaOH로 45% 비누화 된 0.22 M Cyanex 272, 세정용액은 코발트 2 g/L(pH : 3.0), 탈거용액은 코발트 전해폐액(Co 36.0 g/L, $Na_2SO_4\;70g/L$, pH : 1.5)을 사용하였으며, 탈거된 유기상은 산과 증류수의 세척 공정을 통해 재사용하였다. 추출단, 세정단 그리고 탈거단의 O/A 비는 각각 1/1.5, 10/1 그리고 1.5/1 이었으며, 산세척과 수세척단의 O/A 비는 각각 1/1, 6/1이었다. 용매추출공정의 코발트의 추출율과 탈거율은 각각 99.8%와 99.88%이었으며 탈거액의 코발트와 니켈의 농도는 각각 40.27 g/L, 4 ppm이었다. 전해액의 pH 조절을 위해 전해폐액 순환 방식을 도입한 전해채취공정은 $0.563A/dm^2$의 전류밀도에서 67.0%의 전류효율을 나타내었으며, 99.963% 순도의 금속 코발트를 얻었다. A scale up tests (380 kg/day) using a continuous solvent extraction and electro-winning system was carried out to separate and recover cobalt from a solution containing 1.91 g/L Co and 14.65 g/L Ni. The solution was obtained during a process including solvent extraction and precipitation stages for removal of Cu and Fe from a synthetic sulfuric acid solution of manganese nodule matte. The optimal condition for solvent extraction was : solvent concentration of 0.22M Na-Cyanex 272 (45% saponified with NaOH) and O:A phase ratios of 1:1.5, 10:1 and 1.5:1 used in extraction, scrubbing and stripping stages, respectively. The extraction and stripping efficiencies were found to be 99.8% and 99.88%, respectively. The stripped solution contained 40.27 g/L Co with 4 ppm Ni. Cobalt metal of 99.963% purity was yielded with current efficiency of 67% and current density of $0.563A/dm^2$ during the electro-winning process.
박경호,남철우,김홍인,박진태,Park Kyung-Ho,Nam Chul-Woo,Kim Hong-In,Park Jin-Tae 한국자원리싸이클링학회 2005 資源 리싸이클링 Vol.14 No.4
망간단괴 용융환원 시 철과 니켈을 주로 함유하고 있는 Ni-Cd 폐전지와 코발트 등을 함유한 석유화학 폐촉매를 대상으로 첨가 원료로서의 사용 가능성을 검토하였다. Ni-Cd 폐전지의 경우 망간단괴와의 첨가비에 관계없이 $5\%$ 코크스 첨가 시, 주회수 대상 금속인 니켈을 전량 합금상으로 회수할 수 있었다. 한편 폐촉매의 경우 폐촉매의 첨가비가 증가할수록 많은 환원제가 필요한데 이는 폐촉매 중의 코발트가 산화물 형태로 존재하여 이를 환원하기 위한 환원제가 필요하기 때문이다. 본 방법은 금속계 폐자원을 처리하고 동시에 유가금속을 회수할 수 있는 방법으로 향후 망간단괴 개발의 상용화 시 경제성을 증대시키고 폐자원의 재활용에 기여 할 것이다. Deep-sea Manganese nodules was treated with reduction-smelting process with adding the spent Ni-Cd battery or the cobalt contained spent catalyst for recovery of nickel and cobalt metals. The nickel in the spent Ni-Cd battery could be recovered by adding $5\%$ coke as a reducing agent regardless of the amount of battery added. However, to recover cobalt from the spent catalyst, it is require to add more coke for reduction of cobalt oxide in the catalyst. The treatment of metal wastes with manganese nodules can contribute to lower the cost for the processing of nodules and to facilitate the recycling of metal wastes.
박경호,남철우,김현호,Park, Kyung-Ho,Nam, Chul-Woo,Kim, Hyun-Ho 한국자원리싸이클링학회 2015 資源 리싸이클링 Vol.24 No.1
산 침출에 있어서 생성되는 가용성 실리카는 고액분리 시 여과를 어렵게 하고 목적금속의 순도를 저하시키는 등 습식제련공정에 있어서 큰 문제점으로 대두되고 있다. 따라서 본 고에서는 실리케이트 광물과 산과의 반응성, 가용성 실리카의 특성, 제거방법에 대하여 검토하였다. 가용성 실리카는 알카리 전처리에 의한 제거, 결정상태의 $SiO_2$로 변환, 응집 등의 방법을 통한 여과성 향상 등의 방법으로 처리할 수 있다. Soluble silica generated from acid leaching process is very difficult to filter and deceases the purity of products, and thus becomes one of hot issues in hydrometallurgy. This paper reviewed the dissolution and reactivities of silicates in acid solution, and the methods for treatment of soluble silica. Removal of silica with alkaline pre-treatment, crystallization to $SiO_2$ and precipitation behaviour of silica with coagulation under acid conditions were briefly described.