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장영돈,이상래,황의환 大韓口腔顎顔面 放射線學會 1991 Imaging Science in Dentistry Vol.21 No.2
The purpose of this study was to evaluate the incidence and radiographic features of 1,300 cases of supernumerary teeth by means of the analysis of periapical radiograms and/or patomograms in 69,442 persons visited the Department of Oral Radiology, School of Dentistry, Kyung Hee University during January 1980 to December 1989. This study of supernumerary teeth revealed the following features: 1. The incidence of supernumerary tooth was revealed to be 1.5% in total examined persons, and there was a higher incidence in males (74.0%) than in females (26.0%). 2. The supernumerary teeth were most frequently occurred in the 1st decade (42.7%), followed by the 2nd decades (20.2%), the 3rd decades (14.1%), and the 5th decades (7.2%). 3. There was a higher incidence in the maxilla (98.7%) than in the mandible (1.3%), and mesiodens (90.1%) was the most frequently occurred. The maxillary lateral incisor region (3.1%) was next in order of frequency followed by maxillary distomolar (2.2%), and maxillary paramolar (1.5%). 4. There was a higher incidence of the impaction (82.7%) than that of the eruption (17.3%), and supernumerary tooth in lateral incisor region (87.8%) was the most frequently impacted one. 5. The inverted impaction was occurred in 63.1%, the vertical impaction in 18.1%, and the angulated impaction in 18.8%. In localization, a palatally (lingually) impacted supernumerary tooth was occurred in 85.0%, and middle impacted and buccally (labially) impacted supernumerary tooth showed the same incidence (7.5%). 6. A supplemental tooth was occurred in 3.2%, an accessory tooth in 96.8%, and a supplemental tooth was the most frequently occurred in maxillary lateral incisor and mandibular premolar region. 7. In effect of supernumerary tooth on adjacent tooth, crowding was occurred in 0.4%, diastema in 10.6%, rotation in 5.4%, eruption disturbance in 4.5%, root resorption in 2.5%, and dentigerous cyst in 2.2%.
W/Ta_(2)O_(5)/poly-Si/Si에서의 C-V측정
김홍배,장영돈,김종진,신인철 청주대학교 산업과학연구소 1996 産業科學硏究 Vol.14 No.-
W to electrode meterial of Ta_(2)O_(5) oxide have been studied. It evepolated W by sputter and Al by evpolater on S_(1)-polyS_(1)-Ta_(2)O_(5) layer Leakage current characteristics through I-V measurement before and after 500,600℃ annealing was investigated. The MOS capacitor of W-Ta_(2)O_(5)-polyS_(1)-S_(1) structure was made. The electric characteristics resulted in Ta_(2)O_(5) oxide interface through quasi-static and high-frequency C-V measurement was investigated. I-V and C-V measurement to electric charactivistics of each sample were investigated Where I-V measurement recognized Al better then W Al good leakage current a case before and after 500 ℃ annealing. But W good leakage current a case after 600 ℃ annealing. Therfore W good at high temperature. C-V measurement was investigated interface analysis of W-Ta_(2)O_(5)-polyS_(1)-Si capacitor. High-frequency recognized interface fixed oxide charge and capacitance Quasi-static C-V measurement recognized interface trapped charge
김홍배,이상미,장영돈 청주대학교 산업과학연구소 1997 産業科學硏究 Vol.15 No.-
Ta_(2)O_(5) films are recognized as promising dielectric for future DRAM'S and the electrical properties of Ta_(2)O_(5) films greatly depend on the heating condition In this paper, the temperature effect was described by the electrical properties of W/Ta_(2)O_(5)/S_(1) structure when the heating temperature was vaned from 500 to 900 C in N_(2) for 30㎜ and the degree of temperature was 100℃. In ln(J/E^(2)) Vs 1/E plot of typical I-V data, the Fowler-Nordheim tunneling could indicated as the dominant mode of current transports at low temperatures but, could not indicated as the dominant mode of current transports at temperatures above 700℃ due to crystallization of Ta_(2)O_(5) In the high frequency annealing temperature, and increases with annealing temperature, then we would induced to increasing of the densification.