Preparation of Nano-sized Pt Powders by Solution-phase Reduction

김철주,윤호성,조성욱,손정수,Kim, Chul-Joo,Yoon, Ho-Sung,Cho, Sung-Wook,Sohn, Jung-Soo The Korean Institute of Resources Recycling 2007 資源 리싸이클링 Vol.16 No.5

백금은 물리화학적 특성에 기인하여 많은 분야에서 중요한 역할을 하고 있으며, 이러한 분야에서는 아주 미세한 백금의 사용을 요구하고 있다. 그러므로 본 연구에서는 액상에서 환원제를 사용하여 백금염을 환원시킴으로서 나노크기의 백금을 제조하는 방법에 대하여 알아보았다. 수용액상에서 C14TABr과 $H_2[PtCl_6]$ 상호작용은 $[C1_4TA]_2[PtCl_6]$의 유기백금염 화합물을 형성한다. 단분산 나노 백금입자를 얻기 위해서는 $C1_4TABr$과 $H_2[PtCl_6]$ 농도가 각각 cmc와 0.32 mM 이상이 되어야 한다. $H_2[PtCl_6]$와 C14TABr 농도가 증가함에 따라 백금입자 크기가 증가하였으며, 백금입자의 형태는 C14RABr농도 증가에 따라 제어가 가능하였다. Platinum plays an important role in many applications because of its extraordinary physical and chemical properties. All these applications require the use of platinum in the finely divided state. Therefore the preparation of platinum nanoparticles by reducing platinum-surfactant salt with reducing agent in the solution was investigated in this study. The net interaction between C14TABr and $H_2[PtCl_6]$ in aqueous solution results in the formation of $[C14TA]_2[PtCl_6]$. The concentration of C14TABr and the concentration of $H_2[PtCl_6]$ has to be above cmc and 0.32 mM, respectively in order to obtain complex-micelle aggregation for mono dispersed Pt particles. Pt particle size increases with increasing $H_2[PtCl_6]$ and C14TABr concentration. And the shape of Pt particles was well controlled with increasing surfactant concentration.

소디움실리케이트 수용액(水溶液)으로부터 솔-젤 반응(反應)에 의해 제조(製造)된 실리카 솔 입자특성(粒子特性) 고찰(考察)

김철주,김성돈,장희동,윤호성,Kim, Chul-Joo,Kim, Sung-Don,Jang, Hee-Dong,Yoon, Ho-Sung 한국자원리싸이클링학회 2009 資源 리싸이클링 Vol.18 No.6

소디움실리케이트 수용액으로부터 나트륨이온이 제거된 핵생성 산화실리케이트 수용액과 실리케이트 수용액을 pH 10~11로 조절하여 혼합한 다음, $20{\sim}80^{\circ}C$에서 솔-젤 반응하여 실리카 솔 입자를 제조하였다. 이 때 yellow silicomolybdate method를 이용하여 소디움실리케이트와 나트륨이온이 제거된 실리케이트 수용액의 특성과 이들 출발용액으로부터 솔-젤 반응에 의해 제조된 실리카 솔의 입자특성에 대하여 고찰하였다. $SiO_2$를 2 wt% 함유한 소디움실리케이트 수용액은 약 95% 이상의 반응성 실리케이트를 함유하며, 솔-젤 반응에 참여하는 반응성 실리케이트는 전체 실리카 기준 약 50% 정도이다. 반응온도가 증가함에 따라 silanol(Si-OH) 결합구조의 흡수피크 세기는 감소하고, siloxane(Si-O-Si) 결합구조의 흡수피크 세기가 증가하였다. 반응조건별로 제조된 실리카 솔 수용액의 zeta potential은 -40~-60 mV 범위로 분산성이 좋은 상태를 유지하였다. 실리카 솔 입자크기는 5~10 nm로 반응온도 증가에 따라 크기가 약간 감소하였다. 실리카 솔 제조 후, 2차 입자 성장을 위하여 실리케이트 수용액을 재 첨가하였을 경우에 실리카 솔입자 크기가 약 20 nm로 증가하였다. Silica sol was prepared from the mixture of sodium silicate solution and oxidized silicate solution in which sodium had been removed by sol-gel process. The properties of sodium silicate solution and silicate solution thus prepared were characterized by yellow silicomolydate method. Moreover, the formation and growth of silica sol from sodium silicate solution was investigated. Sodium silicate solution with 2% of $SiO_2$ contains 95% of reactive silicate, and 50% of reactive silicate participates sol-gel reaction. From the results of FT-IR analysis, it was found that the intensity of silanol bond decreased and the intensity of siloxane bond increased with increasing reaction temperature. Zeta potential of silica sol prepared at each condition was -40~-60 mV and it could be known that silica sol in this study was well dispersed. The silica sol with 5~10 nm size could be prepared by heating the mixed solution of sodium silicate and silicate solution. And the silica sol grew into about 20 nm as silicate solution was added to silica sol solution.

규산(硅酸)나트륨 수용액(水溶液)의 솔-젤 반응속도론적(反應速度論的) 고찰(考察)

김철주,윤호성,장희동,Kim, Chul-Joo,Yoon, Ho-Sung,Jang, Hee-Dong 한국자원리싸이클링학회 2008 資源 리싸이클링 Vol.17 No.6

본 연구에서는 yellow silicomolybdate method를 이용하여 규산나트륨 수용액의 특성, 핵 생성에 필요한 규산나트륨 수용액의 산화반응 특성 그리고 출발용액의 솔젤 반응특성을 기초로 하여 실리카 솔 형성에 대한 반응속도론적 고찰을 하였다. $SiO_2$를 2wt% 함유한 규산나트륨 수용액은 황산으로 산화시키기에 적당하였으며, 규산나트륨 수용액중의 나트륨 이온을 제거한 후, 안정된 실리 케이트 수용액을 얻기 위한 용액의 pH는 9 이상이었다. 규산종과 실리카 핵 표면 사이의 축중합 반응에 관한 속도론적 연구는 반응온도 $20{\sim}80^{\circ}C$, 수용액의 pH 10에서 수행하였다. 반응은 두 영역으로 구분되는데, 규산종의 농도가 높은 영역에서는 축중합 반응에 의해 제한을 받으며, 낮은 농도 영역에서는 화학흡착된 규산종이 실리카로 응축되는 공정에 영향을 미친다. 전체 축중합 반응은 규산종 농도의 1차 반응으로 진행되며, 축중합 반응은 무정형 실리카의 용해도에 접근하기 보다는 가평형점($C_x$) 향하여 진행된다. 본 연구조건에서 무정형 실리카의 용해열은 3.34 kcal/mol이었고 축중합 반응의 활성화에너지는 3.16 kcal/mol이었다. The properties of sodium silicate solution were surveyed by using the yellow silicomolybdic method, and the formation of silica sol from sodium silicate solution and the growth of silica sol were investigated in this study. The $SiO_2$ content of 2 wt% in sodium silicate solution was proper to oxidize sodium silicate with sulfuric acid. After the removal of sodium ions in sodium silicate solution, the pH of silicate solution had to be controlled above 9 for the stabilization of silicate solution. The condensation between silicic acid species and silica nuclei surfaces has been studied at $20{\sim}80^{\circ}C$ and pH 10 in silicate solutions with silica nuclei. The reaction falls into two kinetics regimes, limited at high silicic acid species concentration by polymerization, but at lower concentration by a process whereby deposited silicic acid species condenses further to silica. The overall condensation is first-order in silicic acid species concentration, proceeded toward to pseudo equilibrium concentration, $C_x$, rather than the solubility of amorphous silica. The heat of solution of amorphous silica was 3.34 kcal/mol and exhibits an Arrhenius temperature dependence with an apparent activation energy of 3.16 kcal/mol in the range of $20{\sim}80^{\circ}C$.

염화네오디뮴 수용액으로부터 탄산네오디뮴 결정화

김철주,윤호성,김준수,이승원,Kim, Chul-Joo,Yoon, Ho-Sung,Kim, Joon-Soo,Lee, Seung-Won 한국자원리싸이클링학회 2007 資源 리싸이클링 Vol.16 No.2

본 연구는 염화네오디뮴 수용액으로부터 탄산수소암모늄의 첨가에 의한 탄산네오디뮴 합성 시, 반응에 따라 형성되는 탄산네오디뮴 결정에 대하여 고찰하였다. 결정형의 탄산네오디뮴을 얻기 위해서는 염화네오디뮴 수용액에 투입되는 탄산수소암모늄 수용액의 농도와 반응온도가 중요한 역할을 한다. 무정형의 탄산네오디뮴은 핵생성을 통한 일차입자들의 응집에 의하여 형성되며, 반응물의 농도 및 반응온도 등을 증가시켜 반응속도를 빠르게 함으로서 결정형의 탄산네오디뮴을 얻을 수 있었다. 또한 반응조건에 따라 lanthanite[$Nd_2(CO_3)_3{\cdot}8H_2O$]와 tengerite[$Nd_2(CO_3)_3{\cdot}2.5H_2O$] 결정구조를 갖는 탄산네오디뮴을 합성할 수 없었으며, lanthanite 구조의 탄산네오디뮴은 온도에 민감하고 불규칙한 모양의 덩어리 형태를 가지며, 반면에 tengerite 구조의 탄산네오디뮴은 침상의 형태를 가지고 있음을 알 수 있다. 열분해 거동 고찰 결과 250까지 탄산네오디뮴의 결정수가 분해되고 $420^{\circ}C$부근에서 $CO_2$가 분해되어 $Nd_2O_2CO_3$가 형성되며, $620^{\circ}C$에서 산화네오디뮴 결정화가 시작하여 $700^{\circ}C$ 부근에서 최종적으로 산화네오디뮴의 형성되는 것을 알 수 있다. 또한 소성된 산화네오디뮴의 형상은 탄산네오디뮴의 형상에 의하여 영향 받고 있음을 알 수 있다. In this study, the crystallization of neodymium carbonate from neodymium chloride solution by addition of ammonium bicarbonate was investigated. The concentration of reactants such as neodymium chloride and ammonium bicarbonate, and reaction temperature play an important part in order to obtain the crystal of neodymium carbonate. It seemed that amorphous neodymium carbonate was prepared by aggregation of primary particles formed through nucleation. If reaction rate was increased by increasing the concentration of reactants and reaction temperature, then neodymium carbonate crystal could be obtained. Lanthanite-type neodymium carbonate[$Nd_2(CO_3)_3{\cdot}8H_2O$] and tengerite-type neodymium carbonate[$Nd_2(CO_3)_3{\cdot}2.5H_2O$] could be obtained with reaction renditions. Lanthanite-type neodymium carbonate was sensitive to temperature. The thermal decomposition of neodymium carbonate contained the processes or dehydration, decarbonation and crystalization of $Nd_2O_3$. The shape of lanthanite-type neodymium carbonate was irregular lump type, and tengerite-type neodymium carbonate had the shape of needle type. The shape of $Nd_2O_3$ was affected by the shape of neodymium carbonate.

네오디뮴 자석 스크랩에서 희토류 원소 선택적 침출 신공정 기술

김철주 ( Chul-joo Kim ),윤호성 ( Ho-sung Yoon ),정경우 ( Kyeong Woo Chung ),임병철 ( Byung-chul Lim ),김정모 ( Jeong-mo Kim ),전수병 ( Su-byung Jeon ) 한국폐기물자원순환학회(구 한국폐기물학회) 2018 한국폐기물자원순환학회 춘계학술발표논문집 Vol.2018 No.-

네오디뮴 자석(Nd₂Fe₁₄B)의 가공·성형시 다량의 스크랩이 발생하는데 발생량이 투입되는 양의 최대 40%를 나타내어 경제적·환경적 측면에서 발생 스크랩의 재활용은 필수적이다. 가공스크랩은 폐자석과는 달리 분말형태로 수집되어 파/분쇄 단계가 필요치 않은 장점이 있으며, 또한, 가공 단계에서 투입된 절삭유에 의해 산소와의 접촉이 억제되어 산화가 발생되지 않은 금속 상태로 존재한다는 특징을 갖고 있다. 이에 본 연구에서는 NaOH 침지후 산화배소 공정을 적용하여 네오디뮴 자석 스크랩의을 직접 산화시킬 시 나타나는 희토류-철 혼합산화물(NdFeO₃)의 생성을 억제하고 희토류 산화물(Nd₂O₃)와 철산화물(Fe₂O₃)를 분리 생성시킴으로서 침출단계에서 철의 침출은 억제하고 희토류만을 선택적으로 침출시켜 향후 희토류 분리정제 및 고순도화 단계에서 희토류/비희토류 분리정제 단계를 생략하고 바로 용매추출에 의한 희토류 고순도화 공정으로의 적용이 가능한 신공정 연구를 수행하였다.

제7차 교육과정 개정안과 기독교교육 문화콘텐츠 개발

김철주(Chul-Joo Kim) 한국기독교교육정보학회 2008 기독교교육정보 Vol.20 No.-

The purpose of this study is to review the contents and directions involved with revised plan of 7th. national curriculum standard for the religion subjects and as a countermeasure to manifest usefulness and necessity of developing christian educational contents. Since the curriculum of mission schools in Korea are influenced by revised plan of curriculum, this study will be beneficial for the secondary christian education classroom. Through three kinds of problem consciousness, the research problem gets more concrete. 1) From the guidance of religion education for the revised plan of 7th. national curriculum standard, what points are the target for the revision 2) In what context and contents involved with the guidance of religion education for the revised plan, 3) As for the revised plan, in what direction is desirable for the design of the future religion education. This study consists of three parts excluding the introductory part and concluding remarks. The 2nd. chapter discusses about guidance of religion education from the 7th. national curriculum The 3rd. chapter analyzes the contents and unique features for the guidance of religion education from the revised plan of 7th. national curriculum. The 4th. chapter suggests the possibility and usability of christian cultural contents that is united with the cultural contents and christian education as a teaching method of christian education If this research points out the problems of revised plan of 7th. national curriculum for the religion subject and necessity and usefulness of development of christian educational contents as a general remark level, finding out the sample cases of application of christian cultural contents to educational practices, the researches to find out effectiveness and efficiency of these methods is needed for the future research. Considering the diversity and scope of christian culture the project of developing christian cultural content should be done as joint effort of groups of missionary schools or support of religious body rather than individual teacher basis.

Esterel에서 근사-제어흐름그래프의 효율적인 생성 (pp.379-380)

김철주(Chul-Joo Kim),윤정한(Jeong-Han Yun),서선애(Sunae Seo),최광무(Kwang-Moo Choe),한태숙(Taisook Han) 한국정보과학회 2009 한국정보과학회 학술발표논문집 Vol.36 No.1

스포츠 조직내 관리 형태에 따른 생활만족과 윤리의식의 관계

김철주(Chul Joo Kim),임효택(Hyo Teak Lim) 한국사회체육학회 2004 한국사회체육학회지 Vol.0 No.21

This study aims to examine life satisfaction and organization effectiveness centering around sports management by its types and sports coaches. For this, it set coaches and sports related administrators as population and obtained total 420 including 205 sports coaches and 215 sports related managers using systematic stratified cluster random sampling. 405 samples excludingl5 samples(3.6%) presenting unfaithful answers or omitted answers among collected data were selected as the subjects of final analysis. This study revised the items of measuring ethical sense developed by Zinn`s ethical dilemma(1993), Duska`s ethical reasoning(1990) and ethical decision making by Zinn(1993) and Cooke (1991) as the questionnaire and was based on questionnaire items revised by Lee Jong-Gil(1992) for measuring life satisfaction developed by Griffin(1985). For measuring life satisfaction of subjects, questionnaire of life satisfaction developed by Griffin (1985) was used and it is found that reliability of questionnaire items through Cronbach` s α was relatively higher as Cronbach`s α=.78, α=.85. Procedures of questionnaire examination were directed to answer questions with self-administering method and completed answers were collected. The answers collected were computerized with SPSS/PC+ 8.0 Version program according to purposes of data analysis and statistical analysis methods used in this study were co-variance analysis and regressive analysis. As a result of analyzing data, it obtained the following conclusions. First, it was found that there was no statistically significant difference in life satisfaction between coaching centered manager and managing centered manager, but sports coaching centered manager group showed higher life satisfaction than sports managing centered manager. Second, there was a statistically significant difference in the ethical, environmental and normative senses between coaching centered manager and managing centered manager. That is, sports coaching centered manager group had higher environmental and normative sense than sports managing centered manager group. Third, life satisfaction had a significant influence on ethical sense. That is, sports coaching centered manager and sports managing centered manager having higher life satisfaction showed higher ethical, environmental, normative and practical senses.

`한국교육사` 교과교재의 종교 서술과 방향

김철주(Kim, Chul-joo),고병철(Ko, Byoungchul) 한국종교학회 2010 宗敎硏究 Vol.58 No.-

청주 신봉동 백제고분군 청주 신봉동 고분군의 보존과 정비 방안에 관한 연구

김철주 ( Chul Joo Kim ) 백제학회 2012 백제학보 Vol.0 No.8

Tombs from the chiefdoms of the prehistoric times to the upper class of the Three Kingdoms period in Korea are important and valuable historic evidence. Through the type and form of the tombs and accompanying artifacts excavated from the tombs, the social, physical, economic and ideological changes of the times are revealed. However, a number of the tombs are in need of better conservation, and some face problems that arise from the management or partial restoration. The establishment of an overall management plan and consideration for the historic and cultural landscape are factors that are essentially needed for the sound conservation of the tombs. This article will focus on the conservation status of the tombs, with particular focus on the Sinbong-dong Tombs, and suggest appropriate methods and approaches for the management and conservation that would fully portray the value and importance of these sites.