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CdTe 감마선 검출소자의 표면거칠기가 Au/CdTe Schottky Barrier의 전기적 특성에 미치는 영향
장충근,송재용,최철규,오희필,황선태 충남대학교 기초과학연구소 1990 연구논문집 Vol.10 No.-
The effects of the surface roughness of CdTe gammaray detector chips on the electrical characteristics of Au/n-CdTe Schottky barrier have been investigated using the Schottky diode prepared with he surface roughness in the range of 0.1∼0.5㎛. Measured for the diode are the electrical resistance characteristics, the potential barrier height and the electrical noise. The dynamic resistance is observed to decrease exponentially as R_d=370exp(-9.94ㆍRa)with the surface roughness(Ra) of the CdTe wafers. The potential barrier hight shows an exponential decay like ∮_B=0.88exp(-0.75ㆍRa) with the increase in roughness while the electrical noise shows a linear growth.
여재 특성에 따른 강우 유출수 내 오염물질 제거특성 평가
김태균(Tae Gyun Kim),조강우(Kang Woo Cho),송경근(Kyung Guen Song),윤민혁(Min Hyuk Yoon),안규홍(Kyu Hong Ahn),홍승관(Sung Kwan Hong) 大韓環境工學會 2009 대한환경공학회지 Vol.31 No.7
본 연구의 목적은 도시지역 강우유출수 내에 존재하는 다양한 오염물질에 대한 여과장치의 제거 효율을 평가하고 여재의 특성에 따른 설계인자를 도출하는데 있다. 비점오염물질 제어기술로서 여과 장치 내에 충전될 여재의 선정은 여과장치의 수명과 크기를 결정하는 중요한 요소이다. 본 연구에서는 컬럼운전을 수행함으로써 펄라이트와 합성여재의 강우유출수 내에 존재하는 오염물질에 대한 제거능을 조사하였다. 각 여재의 양이온교환능력 (CEC) 및 제타전위 등 여재의 표면특성을 분석한 결과 펄라이트가 양이온계 오염물질의 흡착에 있어서는 더 우수한 것으로 나타났다. 또한 컬럼 운전 수행 결과 입자성 오염물질인 TCOD(Cr)와 탁도는 초기 2.5분의 접촉시간만 가지고도 대부분의 제거가 가능한 것을 확인할 수 있었다. 한편 수리학적 특성에 있어 EBCT (empty bed contact time) 2.5분의 시점에서 살펴보았을 때 폐색이 발생한 시점은 펄라이트는 630분, 합성여재에서는 810분으로 동일 조건에서 합성여재의 운전 수명이 더 긴 것으로 나타났다. 용존성 오염물질인 SCOD(Cr)에 대하여서는 두 여재 모두 뚜렷한 제거 특성이 보이지 않았으며 이 결과는 흡착에 필요한 접촉시간이 확보되지 못한 것으로 판단된다. 마지막으로 여재의 표면 특성인 양이온 교환능력과 중금속 제거효율 사이의 상관관계는 찾아볼 수 없어 대부분 입자에 포획된 상태로 제거됨을 알 수 있었다. 본 연구의 결과는 향후 도시지역 강우유출 수 처리를 위한 여과장치 설계 및 적정 여재 선정에 있어 중요한 자료로 활용될 수 있을 것이다. The aims of this study were to evaluate the removal efficiency for various pollutants in urban storm runoff by a filtration device, and to determine design parameters depending on filter media properties. Appropriate selection of filter media will affect the size and life time of the filtration device. Sets of column tests were performed in order to evaluate the removal efficiency by perlite and a synthetic resin. An investigation of surface properties including CEC (cation exchange capacity) and zeta-potential suggested that the perlite had a superior adsorption capability for cationic pollutants. TCODcr and turbidity were analyzed to investigate the removal characteristic of particulate pollutant. In both columns, the particles in the collected storm runoff was almost completely capture with a small EBCT (empty bed contact time) of 2.5 minutes. Complete clogging at the EBCT of 2.5 minutes occurred after 630 minutes in the perlite column and 810 minutes in the resin column. The removal efficiency of TCODcr and turbidity at the EBCT of 2.5 minutes decreased to below 70% due to an wall effect. The removal efficiency for dissolved pollutant (SCODcr) was negligible due to the insufficient contact time for adsorption. The removal of heavy metals (Cu, Zn, Pb) was mostly ascribed to the filtration of particles containing metals, since the relationship between CEC and the removal efficiency was not apparent. The result of this study would be valuable for the application of filtration device to control of urban storm runoff.
김태오,강대환,양웅석,조몽,송철수,송근암,김형욱,류수형 대한소화기학회 1999 대한소화기학회지 Vol.34 No.4
Background/Aims: In viral hepatitis, it is unclear whether iron and copper play a role in the pathogenesis of hepatic injury. The purpose of this study was to investigate the presence of correlation between the hepatic concentrations of these metals and the grades of inflammation or stages of fibrosis in patients with chronic viral hepatitis. Methods: This study included 53 patients consisting of 44 patients with chronic hepatitis B, 6 patients with chronic hepatitis C, and 3 patients with cirrhosis. Hepatic iron and copper concentrations were determined by Inductively Coupled Plasma- Atomic Emission Spectrometry. Results: Average hepatic iron concentration was 583.2±606.5 ㎍/g dry weight. In one patient (1.9%), hepatic iron concentration was unusually high (4573.0 ㎍/g dry weight). Hepatic iron concentrations were not different according to the grade of portal/periportal and lobular inflammation, or the stage of fibrosis. Average hepatic copper concentration was 65.3±35.3 ㎍/g dry weight and hepatic coponcentrations were increased in 25 patients (47.2%). Hepatic copper concentrations were significantly related with the grade of portal/periportal inflammation (rs=0.475, p$lt;0.001), lobular inflammation (rs=0.362, p=0.008), and the stage of fibrosis (rs=0.410, p=0.002). Conclusions: These results suggest that copper may have an important role as a cofactor in the pathogenesis of hepatic injury in chronic viral hepatitis.