Vacuum Ultra Violet Spectroscopic Ellipsometry 를 이용한 BaSm₂Ti₄O<SUB>12</SUB> 의 광 특성 연구

황순용(S. Y. Hwanga),윤재진(J. J. Yoon),정용우(Y. W. Jung),변준석(J. S. Byun),김영동(Y. D. Kim),정영훈(Y. H. Jeong),남산(S. Nahm) 한국진공학회(ASCT) 2009 Applied Science and Convergence Technology Vol.18 No.1

본 연구에서는 분광타원분석법을 이용하여 최근 주목 받고 있는 microwave dielectric materials 인 BaSm₂Ti₄O12 박막의 광특성을 0.92 ~ 8.6 eV 에너지 영역에서 분석하였다. 광역 에너지영역에서 측정이 가능한 Vacuum Ultra Violet spectroscopic ellipsometer 를 사용하여 시료의 광 스펙트럼을 측정 하였으며, 측정된 스펙트럼으로부터 BaSm₂Ti₄O12 박막의 광 특성을 얻기 위하여 Tauc-Lorentz 분산 함수를 이용하였고, 고 에너지 영역대의 새로운 피크구조 (structure) 를 최초로 발견하였다. We performed a study on optical properties of BaSm₂Ti₄O12 thin films by vacuum ultra violet spectroscopic ellipsometry in the 0.92~8.6 eV energy range. For the analysis of the measured ellipsometric spectra, a 5-layer model was applied where optical property of the BaSm₂Ti₄O12 layer was well represented by a Tauc-Lorentz dispersion function. Our analysis clearly showed new structure in high energy region at about 7.5 eV. Consistent changes of refractive index & extinction coefficient of the BaSm₂Ti₄O12 thin film by the growth and annealing temperatures were also confirmed.

Vacuum Ultra Violet Spectroscopic Ellipsometry를 이용한 BaSm₂Ti₄O₁₂의 광 특성 연구

황순용,윤재진,정용우,변준석,김영동,정영훈,남산,Hwang, S.Y.,Yoon, J.J.,Jung, Y.W.,Byun, J.S.,Kim, Y.D.,Jeong, Y.H.,Nahm, S. 한국진공학회 2009 Applied Science and Convergence Technology Vol.18 No.1

본 연구에서는 분광타원분석법을 이용하여 최근 주목 받고 있는 microwave dielectric materials 인 $BaSm_2Ti_4O_{12}$ 박막의 광 특성을 $0.92{\sim}8.6\;eV$ 에너지 영역에서 분석하였다. 광역 에너지영역에서 측정이 가능한 Vacuum Ultra Violet spectroscopic ellipsometer를 사용하여 시료의 광 스펙트럼을 측정 하였으며, 측정된 스펙트럼으로부터 $BaSm_2Ti_4O_{12}$ 박막의 광 특성을 얻기 위하여 Tauc-Lorentz 분산 함수를 이용하였고, 고 에너지 영역대의 새로운 피크구조 (structure) 를 최초로 발견하였다. We performed a study on optical properties of $BaSm_2Ti_4O_{12}$ thin films by vacuum ultra violet spectroscopic ellipsometry in the $0.92{\sim}8.6\;eV$ energy range. For the analysis of the measured ellipsometric spectra, a 5-layer model was applied where optical property of the $BaSm_2Ti_4O_{12}$ layer was well represented by a Tauc-Lorentz dispersion function. Our analysis clearly showed new structure in high energy region at about 7.5 eV Consistent changes of refractive index & extinction coefficient of the $BaSm_2Ti_4O_{12}$ thin film by the growth and annealing temperatures were also confirmed.

육류의 안전성 평가기술 연구

이정일,이무하,민중석,김일석,이상옥,신대근,변준석,강석남 한국축산학회 1998 한국축산학회지 Vol.40 No.4

Microorganisms were taken at the surfaces of pork and beef. Microbial sampling of pork was carried out at 4 steps, i.e. immediately after slaughtering(PA), at 24hrs after slaughtering(PB), before deboning(PC) and after deboning(PD). And the sampling of beef was carried out at 5 steps, i.e. immediately after slaughtering(BA), at 6hrs after slaughtering(BB), at 24hrs after slaughtermg(BC), before deboning(BD) and after deboning(BE). Total plate count was significantly higher in the step before deboning(PC) than in the other steps of pork processing(P$lt;0.05). The numbers of coliforms and E. coli increased in proportion to the total plate counts. Microbial contamination was significantly higher in the step before deboning than any other step of beef processing(P$lt;0.05). The step immediately after slaughtering(BA) was the next highest level in microbial contamination. The results of multiple regression analysis among total plate counts, coliforms and E. coli showed that determination coefficients(R²) were as high as 0.8307-0.9971. This meant that E. coli increased as total plate counts and coliforms increased. The results of PMP(pathogen model program) analysis showed that pathogenic microorganisms grew similarly in low ambient temperature(5℃), while they grew faster as ther initial numbers were high. In the same initial number, growth rate was 10 times faster in 15℃ than in low ambient temperature(5℃) and 4 times faster in 25℃ than in 15℃.

국내시장에 유통중인 한우 및 수입 쇠고기 냉동 등심 부위의 물리 화학적 미생물학적 및 관능적 품질 특성

이무하,민중석,김일석,변준석,강석남,이상욱 한국축산학회 2000 한국축산학회지 Vol.42 No.1

This study was carried out to compare qualities of the frozen imported beef loins with those of the Han-woo beef loins. Samples were stored at -20℃. In the proximate analysis of composition of beef loins, there were significant differences in crude fat, crude protein and moisture(P$lt;0.001). Han-woo loins were higher in crude protein and moisture than those of the other loins. In the analysis of microorganisms, TPC(Total Plate Counts) and psychrotroph bacterial counts of the Han-woo loins showed the lowest value. TBARS(Thiobarbituric Acid Reactive Substance) values were less than 0.4㎎MA/㎏ in all samples, VBN(Volatile Basic Nitrogen) values were less than 20㎎/100g in all samples. In the descriptive analysis with scaling for raw and cooked beef loins, it was observed that off-flavor of American raw beef loins was higher than that of other ones. In cooked beef loins, acceptability was higher in the Han-woo loins than in the imported ones.

식품의 콜레스테롤 산화물질 분리 및 정량

이정일,이무하,변준석,강석남 한국축산학회 1998 한국축산학회지 Vol.40 No.5

This experiment was carried out to identify and quantify cholestrerol oxides from meat(Dongrandaeng, Frankfurter sausage, Press ham, Mandu and Vienna sausage), milk(Bioghurt, Butter, Cheese, Icecream, Dry-milk and Yoghurt) arid dried-fish products(anchovy, codfish, shrimp, cuttlefish and filefish) marketed in Korea. The ranges of β-epoxide, 19-hydroxycholestriol, 7 β-hydroxycholesterol and α-epoxide detected in all the meat products were 0.1∼4.73, 0∼1.99, 0.1∼11.06 and 0.1∼6.16 ㎍/g, respectively. Cholestanetriol was detected slightly(below 0.1 ㎍/g). But 22-ketocholesterol and 6-ketocholesterol were not detected in them. Kinds of cholesterol oxides detected in the milk products were similar to those of the meat products. Relatively high amount of 7 β-hydroxycholesterol were detected in the milks(14.25-79.64㎍/g). On the other hand, 22-ketocholesterol and 6-ketocholesterol were not detected. Cheese were found to contain largest amounts of cholesterol oxides in the milk products(P$lt;0.05). The contents β-epoxide, 7 β-hydroxycholesterol, α-epoxide and 7-ketocholesterol detected in the driedfish products ranged 1.38∼86.25, 9.21∼167.36, 1.98∼10.85, and 3.83∼16.57㎍/g, respectively. The amount of cholestanetriol was very low(below 0.1㎍/g), and 22-ketocholesterol, 6-ketocholesterol, 19-hydroxycholestriol, 20 α-hydroxycholesterol and 25-hydroxycholesterol were not detected in the dried-fish processing products. Cuttlefish was found to contain the largest amounts of cholesterol oxides among the fish products(P$lt;0.05).

국내시장에 유통중인 국내산과 외국산 냉동 삼겹살의 품질 특성 비교

김일석,신대근,이상옥,변준석,강석남,이무하 한국축산학회 1999 한국축산학회지 Vol.41 No.2

This study was carried out to compare qualities of the imported frozen pork bellies (Danish and Swedish) with those of the domestic frozen bellies (A and B). Samples were analyzed for compositions, microorganisms and physicochemical characteristics (TBARS, VBN, pH, color, cooking loss). The results of the proximate analysis of compositions showed that moisture, crude protein and crude ash of Swedish belly were higher than those of the other bellies. On the other hand, crude fat of Swedish belly was the lowest (25.28±2.02%). Especially, there was a significant difference in crude protein(P$lt; 0.01). Total plate counts (TPC) of the domestic pork belly (B) showed the highest value(10^(5)SCFU/㎠). TBARS (Thiobarbituric Acid Reactive Substance) values were less than 4.0㎎MA/㎏ in all samples, which is the threshold for ediblity. VBN (Volatile Basic Nitrogen) values were less than 20㎎/100g in all samples. In analysis of meat color, lightness (CIE L*) and redness (CIE a*), values for domestic belly (A) were significantly higher than those of the others(P$lt; 0.01). The range of pH values was from 5.62 to 5.78, but there were no significant differences among the samples.