The Effect of Coolant Boiling on the Molten Metal Pool Heat Transfer with Local Solidification

Cho, Jea-Seon,Kune Y. Suh,Chung, Chang-Hyun,Park, Rae-Joon,Kim, Sang-Baik Korean Nuclear Society 2000 Nuclear Engineering and Technology Vol.32 No.1

This study is concerned with the experimental test and numerical analysis of the heat transfer and solidification of the molten metal pool with overlying coolant with boiling. In the test, the metal pool is heated from the bottom surface and coolant is injected onto the molten metal pool. Experiments were performed by changing the test section bottom surface temperature of the metal layer and the coolant injection rate. The two-phase boiling coolant experimental results are compared against the dry test data without coolant or solidification of the molten metal pool, and against the crust formation experiment with subcooled coolant. Also, a numerical analysis is performed to check on the measured data. The numerical program is developed using the enthalpy method, the finite volume method and the SIMPLER algorithm. The experimental results of the heat transfer show general agreement with the calculated values. The present empirical test and numerical results of the heat transfer on the molten metal pool are apparently higher than those without coolant boiling. This is probably because this experiment was performed in concurrence of solidification in the molten metal pool and the rapid boiling of the coolant. The other experiments were performed without coolant boiling and the correlation was developed for the pure molten metal without phase change.

Carburization of Iron Using CO-H₂ Gas Mixture

Hwang, Ho-Sun,Chung, Uoo-Chang,Chung, Won-Sub,Cho, Young-Rae,Jung, Byong-Ho,Martin G.P. 대한금속재료학회 2004 METALS AND MATERIALS International Vol.10 No.1

Iron carbides formed on the surface of iron and iron oxide samples at 640℃ in a gas mixture of CO-H₂ were characterized by scanning electron microscopy (SEM), MGssbauer spectroscopy, X-ray diffraction patterns (XRD), and by measuring mass change. The Fe₃C amount of the samples has been quantitatively evaluated by the weight change during carburization. While Fe₂O₃ powder was mostly completed to Fe₃C in the early stage, within 5 min after reduction reactions, the conversion of Fe powder sample to Fe₃C (iron carbide) was almost finished after 10 min. The carburization rate of a Fe sheet was very slow and intermediate products (Fe₂C, Fe₃C₂) were observed. This phenomenon is largely due to the difficulty of carbon diffusion into its dense surface. It was found that the carburization rate was affected by change of surface conditions and surface area by reduction, degradation, and cracks at high temperature. This study should help provide a fundamental understanding of carburization in the field of iron-making and suggest a direction for its further development.

Fe 중에 Nd확산에 관한 연구(R-D반응의 기초연구)

조통래,송창빈,김대수 忠南大學校 産業技術硏究所 1992 산업기술연구논문집 Vol.7 No.1

The growth of intermetallic compounds of rare earth-transition metal has been investigated by the reduction process. Nd was diffused into Fe block and made intermetallic compounds, only the Nd₂Fe17 diffusion layer was obtained for the Nd-Fe system. It was shown that the growth rate of intermetallic compounes was controlled by diffusion. Apprarent activation energy for the diffusion of Nd was 28.5Kcal/mol through arrhenius plots.

900℃, 800℃에서의 Pb-Cu-S 3元系의 狀態圖

趙統來,元昌煥 충남대학교 공업교육연구소 1985 論文集 Vol.8 No.1

Ternary miscibility gap (phase diagram) of the Pb-Cu-S System is important to smelting of lead and copper. We are experimentally determinded this System of 1250∼1000℃ This paper is also experimentally determined the ternary mircibility gap of the Pb-Cu-S System at 900∼800℃ the result obtained at 900℃, 800℃, are shown below. 1. Three phase region of 900℃ in wider than at 1000℃. But type of plase diagram at 900℃ is similer of 1000℃. 2. The plase diagram of 800℃ is alomost Same at 900℃.

남성 척수손상 장애인에서 Derogatis성기능 검사(DSFI)를 통한 성기능 평가

박창일,신지철,김덕용,조성래,곽은희 大韓再活醫學會 2000 Annals of Rehabilitation Medicine Vol.24 No.3

미세 펄스 전압을 이용한 마이크로 전해가공에 관한 연구

조창래,백승엽,이은상 한국공작기계학회 2003 한국공작기계학회 추계학술대회논문집 Vol.2003 No.-

Electrochemical micromachining which is not normally considered as a precision process is presented in this paper. The application of voltage pulses between a tool electrode and a workpiece in an electrochemical environment allows the three-dimensional machining of conducting materials with micrometer precision. In this paper tool-electrodes(5μm in diameter, l㎜ in length) are developed by electrochemical micromaching and micro holes are manufactured using this tool-electrodes we developed already. Micro holes are achieved the accuracy below 50μm in diameter using ultrashort voltage pulses(0.1-5μs).

거래조성기능에 대한 생산자 반응 조사 분석

최창렬,조덕래 진주산업대학교 산업과학기술연구소 2007 산업과학기술연구소보 Vol.- No.14

The purpose of this article is to analyze garlic farmer's adaptation for facilitating function in Namhae region. To carry out this objective, adjusting behavior of facilitating function for 150 garlic farmers were investigated. Included main analyzing contents are concentration and packaging, market information and financing, brand and indication certification. In order to raise the efficiency of facilitating function, the effort of garlic farmers are more desired. For example, it is necessary that increasing the concern of garlic farmers for the traceability and indication certification to adjust market environment more and more. And large investment for distribution equipments to improve facilitating function is very important.

환원ㆍ확산법에 의한Sm₂Co계 영구자석 재료의 제조에 있어서 조성제어에 관한 연구

송창빈,조통래 忠南大學校 産業技術硏究所 1994 산업기술연구논문집 Vol.9 No.2

The reduction-diffusion(R-D process) is an economical way of producing funtional materials which contain rare-earth elements and has been applied to the production of magnet meterials, hydrogen storage alloys, etc. However, The process has not been applied to the production of materials having various alloying elements or strictly controlled composition, because conpositions of of the R-D process products are controlled by diffusion in solid phase. This report describes the way of controlling the final composition of the Sm₂Co type (2-17type) rare-earth magnet material in the process which contains Fe, Cu and Zr besides Sm and Co. The magnetic properties were measured at room temperature with the vibrating sample magnetometer(VSM) in the maximum pulsed field of about 15kOe that samples were prepared by the melting method and R-D process.

금융기관의 특성에 따른 자산·부채 종합관리 성과차이 분석 : 금융기관의 종류 및 규모를 중심으로

박창래,조병창 강릉대학교 영동산업문제연구소 1996 産經論叢 Vol.17 No.-

진폐진행정도에 따른 혈청내 구리와 아연 농도의 변동

박정래,박종욱,이수일,이철호,오차재,김창원,조병만,김돈균 大韓産業醫學會 2000 대한직업환경의학회지 Vol.12 No.3

목 적 : 진폐증은 분진으로 인해 인체의 면역기전이 작용하여 폐섬유화가 진행되는 질환으로, 인체의 면역기전에 작용하는 구리와 아연은 진폐증의 병리적인 진행과정인 폐섬유화에 관여한다. 본 연구의 목적은 초기진폐증 유소견자와 진행된 진폐증 환자의 혈청 구리와 아연의 농도를 정상인과 비교함으로써 체내 구리와 아연의 농도가 진폐증의 섬유화의 진행정도에 따라 변동함을 밝히고, 이를 이용하여 폐섬유화의 진행정도를 추정할 수 있는 지표를 제시하고자 한다. 방 법 : 진폐정밀기관에 내원한 초진내 원자 100명과 진폐요양기관에 입원한 진폐증 환자 100명을 선정한 후 흥부사진소견을 ILO 분류법의 진폐진행정도에 따라 각각 세 군(Stage Vl, V2, V3 & Stage Pl, P2, P3)으로 구분한 후 각 군의 혈청구리와 아연의 농도를 비교분석하였다. 대조군으로는 폐결핵, 심근경색, 뇌경색을 경험한 적이 없는 일반인 100명을 선정하였다. 결 과 : 초진내 원자군의 혈청 구리농도는 섬유화의 진행단계에 따른 유의한 차이를 보였으며, Stage V3에서 가장 높았다. 입원환자군에서는 혈청 구리농도가 대조군과 유의한 차이를 보이지 않는데 (p=0, 152), 이는 입원환자의 불량한 영양상태와 건강상태 때문인 것으로 추정된다. 초진내원자군과 입원환자군의 혈청 아연농도는 섬유화의 진행에 따라 통계적인 차이를 보였으며, Stage V2와 Stage P2, P3에서 각각 대조군에 비해 유의하게 낮았다. 혈청 아연과 구리농도의 비또한 양군에서 섬유화의 진행에 따라 의미있게 높았는데, 섬유화가 현저히 진행된 단계 (Stage V3, Stage P2, P3)에서 대조군과 의미있는 차이를 보였다. 결 론 : 초진내 원자와 입원환자의 혈청 Cu/zrl 비는 섬유화의 진행정도가 현저할수록 대조군에 비해 유의하게 높게 나타났다. 진폐증 환자들의 혈청 Cu/zn 비는 진폐증의 폐섬유화의 진행정도를 추정함에 있어 상당히 유용한 지표로 이용될 수 있으며, 폐섬유화의 진행과정에서의 혈청 구리와 아연의 작용기전을 이용한 치료방법의 마련에도 도움이 될 것으로 판단한다. Objectives : Copper and Zinc, the trace elements of a living body, take a part in immunologic mechanism and induce the pulmonary fibrosis which is the pathologic progress of pneumoconiosis. This study was performed to assist the identification of the pathologic process of pulmonary fibrosis in pneumoconiosis. Methods : The subjects of thls study was 200 diagnosed persons as pneumoconiosis, of whom 700 persons was the visitors in the outpatients departments of pneumoconiosis and 100 admissive pneumoconiosis patients. The serum copper and zinc are measured and compared. Results : The mean serum copper concentration of visitor group was significantly higher than that of control group, and that of stage V3 subgroup of visitor group was highest because of their advanced fibrosis. But, there was not the difference of serum copper concentration between patient and control group. We thought that the reason was poor nutritional and health status of the patient. The mean of serum zinc concentration of visitor and patient control was lower than that of control group. As the degree of pulmonary fibrosis was more severe from stage Vl, V2, V3 of visitor to stage Pl, P2, P3 of patient, the mean of serum zinc concentration was lower. The ratio of serum copper/zinc of visitor and patient was higher than that of control, and that of patient was higher than that of visitor. Those results showed that the ratio of serum copper/zlnc ratio more greatly expressed the degree of progression of pneumoconiosis than only copper or zinc concentration by adjustment of nutritional and health status of the patient. Conclusions : As above study results, the degree of pulmonary fibrosis of pneumoconiosis could be estimated by means of serum copper/zinc ratio.