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Czochralski법을 이용한 금속 단결정의 성장과 구조적, 전기적 성질에 관한 연구
박정훈,차수영,박상언,김성규,조채룡,박혁규,김형찬,정명화,정세영,Park, Jeung-Hun,Cha, Su-Young,Park, Sang-Eon,Kim, Sung-Kyu,Cho, Chae-Ryong,Park, Hyuk-K.,Kim, Hyung-Chan,Jeong, Myung-Hwa,Jeong, Se-Young 한국결정학회 2005 韓國結晶學會誌 Vol.16 No.2
It is well known that the general metals have a lot of grain boundaries. The grain boundaries play a negative role to increase the resistivity and to decrease the conductivity. The small resistivity and the large conductivity have been a goal of the material scientists, and no signal noise, perfect signal transfer, and the realization of the real sound are the dream of electronic engineers and audio manias. Generally, oxygen free copper (OFC) and Ohno continuous casting (OCC) copper cables have been used for the purpose of the precise signal transfer and low noise. However they still include a lot of grain boundaries. In our study, we have grown the single crystal by the Czochralski method and succeeded to produce single crystal wires from the crystal in the dimension of $0.5{\times}0.5{\times}2500mm$. The produced wire still possesses very good single crystal properties. We observed the structure of the wire, and measured the resistance and impedance. Glow Discharge Spectrometer (GDS) was used for analyzing the compositions of copper single crystals and commercial copper. Current-Voltage curve, resistance, total harmonic distortion and speaker frequency response were measured for comparing electrical and acoustic properties of two samples.
박정훈,Park, Jeong-Hun 한국방위산업진흥회 1993 國防과 技術 Vol.- No.173
열상장비는 공중이나 지상에서 더욱 발전 할 전망이며, 이에 대처하지 못하는 장비나 시설들은 적의 탐측장비에 즉시 노출되며, 이는 곧 파괴됨을 의미합니다. 그러나 아직까지 열적외선 위장망에 대한 인식이 부족한 상태에 있습니다 열적외선 위장망은 고가의 장비에 약간의 추가적인 부담을 더함으로써, 실질적인 수명의 연장 및 전투력 증강에 기여할수 있는 분야로, 아군의 사기진작과 전투력향상에 기여합니다
Atrazine의 토양 흡착 및 탈착에 미치는 접촉시간의 영향
박정훈,Park Jeong-Hun 한국지하수토양환경학회 2005 지하수토양환경 Vol.10 No.1
The effects of soil-chemical contact time (aging) on sorption and desorption of atrazine were studied in soil slurries because aging is an important determinant affecting on the sorption and desorption characteristics of organic contaminants in the environment. Sorption isotherm and desorption kinetic experiments were performed, and soilwater distribution coefficients and desorption rate parameters were evaluated using linear and non-linear sorption equations and a three-site desorption model, respectively. Aging time for sorption of atrazine in sterilized soil slurries ranged from 2 days to 8 months. Atrazine sorption isotherms were nearly linear $(r^2\;>\;0.97)$ and sorption coefficients were strongly correlated to soil organic carbon content. Sorption distribution coefficients $(K_d)$ increased with increasing aging in all soils studied. Sorption non-linearity did not increase with increased aging except for the Houghton muck soil. Desorption profiles were well described by the three-site desorption model. The equilibrium site fraction $(f_{eq})$ decreased and the non-desorbable site fraction $(f_{nd})$ increased as a function of aging time in all soils. In all soils studied, it was found that when normalized to soil organic matter content the concentration of atrazine in desorbable sites was comparatively constant, whereas that in non-desorbable site increased as aging increased. 토양과 유기화합물의 접촉시간은 흡착과 탈착의 특성에 영향을 미치는 중요한 요소 중의 하나이다. 본 연구에서는 atrazine의 토양 흡착과 탈착에 미치는 접촉시간의 영향을 연구하였다. 등온 흡착실험을 수행하여 토양과 수용액 사이의 분배계수를 구하였고, 탈착에 대한 동력학 실험을 수행하고 three-site desorption모델을 이용, 회기분석 하여 탈착속도 계수들을 추산하였다. atrazine과 토양의 접촉시간은 2일에서부터 8개월까지 변화시켰다. 2일 흡착에 대한 atrazine의 흡착등온 곡선은 거의 선형이었고$(r^2>0.97)$, 흡착분배계수는 토양의 유기탄소 함량과 강한 양의 상관관계를 가졌으며 사용한 모든 토양에서 접촉시간이 길어질수록 증가하였다. 흡착곡선에서의 비선형성은 Houghton muck토양을 제외하고는 접촉시간에 따라 증가하지 않았다. 탈착실험 분석으로부터 접촉시간이 증가함에 따라 equilibrium site분율은 감소하고 non-desorbable site 분율은 증가함을 알 수 있었다. 사용한 모든 토양에서 토양유기탄소 함량으로 표준화한 경우 desorbable sites 에서의 atrazine농도는 접촉시간에 따라 비교적 일정한 것에 비해 non-desorbable site에서의 atrazine농도는 접촉시간이 증가함에 따라 증가하였다.
박정훈,유홍희,Park, Jeong-Hun,Yu, Hong-Hui 대한기계학회 2000 大韓機械學會論文集A Vol.24 No.7
A modelling method for the bending vibration analysis of rotating cantilever beams employing finite element method is presented in this paper. Different from the conventional modelling method in wh ich only Cartesian deformation variables are used, a non-Cartesian deformation variable is introduced and approximated to derive the equations of motion. Numerical results obtained by using the presented modelling method are compared to those obtained by using other methods in the related literature, and the accuracy of the presented method is verified through the comparison study. The presented modelling method is superior to other previous methods in a sense that several advantages of the previous methods are incorporated into the presented method.