Clostridium속 세균포자의 안정성과 Plasmids 탐색

윤기홍,이정기,김병홍,소선주,전영숙,권기석,Z.G.Zeikus 한국산업미생물학회 1990 한국미생물·생명공학회지 Vol.18 No.2

제1, 2차세계대전 동안 분리되어 soil culture로 보존되어 온 131주의 Clostridium속 세균 중에서 100주가 재생되어 76%의 높은 재생력을 보여주었다. 이들 재생균주들의 발효산물을 분석한 결과, 주요산물이 acetone, ethanol 및 butanol인 solvent 생산균들은 63주이고 acetic acid와 butyric acid를 생성하는 산 생성균은 37주였다. 재생된 100주 중 plasmid를 갖는 strain은 50주로 plasmid 함유율은 50%였다. 균주에 따라서 하나에서 여러 개의 plasmids를 가지고 있었으며 그 크기는 1.0kb에서 50kb에 달하였다. Stock cultures of Clostridium, which had been maintained as spores with soil as carrier for 50-70 years, were used to determine their revival ratio, and plasmids were screened among the revived strains. From 131 soil cultures, 100 strains grew in the liguid medium giving the revival ratio of 76%. Analyses of the fermentation products divided the revived strains into 63 solventogenic strains and 37 acidogenic strains. Agarose gel electrophoresis showed one or more plasmid bands in the cleared lysates of 50 revived cultures. The sizes of the plasmids range in size from 1 to more than 50 kilobase pairs.

A Study on the Better Operation of Occupational Safety and Health Management Systems

Choi, Jae-Wook,Yoon, Seok-J.,Lee, Gwan-Hyung,Yang, H.S. The Korean Society of Safety 2005 International Journal of Safety Vol.4 No.1

This study was conducted to identity the characteristics of occupational health and safety management systems around the world, to survey the implementation of OHSMS in Korean companies, to find problems and corrective measures, and to understand the opinions of top management about OHSMS. Questionnaires on the operation of occupational health and safety management systems in Korean manufacturing companies were carried out. Occupational health and safety management systems around the world, including OHSAS 18001, BS8800, KOSHA 18001, VPP, J-OHSMS, were reviewed. In order to implement an occupational health and safety management system successfully, it was found that the management should consider occupational health and safety as important, provide employees with necessary training, and have a strong commitment to occupational health and safety.

표면탄성파를 이용한 마모 표면부의 평가

권성덕,윤석수,송성진,이영제 한국비파괴검사학회 2002 한국비파괴검사학회지 Vol.22 No.2

레일리(Rayleigh) 표면탄성파의 속도와 산란의 주파수 의존성을 이용하여 마모로 인해 열화된 AISI 1045강 시편의 깊이방향 잔류응력 분포(열화 기울기)의 비파괴적인 평가가 시도되었다. 액체/고체 경계면에 초음파가 특정각도로 입사할 때 발생한 표면탄성파의 산란과 복사로 인해 나타나는 후방복사 프로파일의 오른쪽 반치폭과 크기 그리고 발생각으로 잔류응력 분포의 해석도 가능하였으며 평균법에 의한 복사파의 세기 및 스펙트럼의 변화는 잔류응력 분포의 열화로 인해 발생한 미세 결함 밀도와의 연관성을 보여주었다. The frequency dependency of the Rayleigh surface wave was investgated indirectly by measuring the angular dependency of the backward radistion of the incident ultrasonic wave in the abrasion specimens, which was explained in view of the residual stress distribution. The peak intensity of the backward radiation profile decreased and the right halt width of the profile increased with an increase of the variational rate of residual stress for the scuffing specimen. The peak intency was also affected by the surface wave scattering during the propagation around the micro damages. The peak angle might depend on not only the amount of residual stress but also the micro-structure. The result observed in this study demonstrates the high potential od the backwatd radiated ultrasound as a tool for the nondestructive evaluation of the subsurface gradients of materials.

혈액투석 중인 만성 신부전 환자에서 TT Virus의 감염률과 임상적 의의

이용욱,허우성,도재혁,백승운,최문석,김소정,이준행,고광철,이풍렬,이종철,최규완,박상종,이준혁,김재준,오하영,임윤정 대한소화기학회 2001 대한소화기학회지 Vol.37 No.1

Background/Aims: TT virus (TTV) is a unenveloped, single-stranded and circular DNA virus isolated from the serum of a patient with posttransfusion hepatitis of unknown etiology. We evaluated the prevalence, risk factors, and clinical significance of TTV in patients with chronic renal failure(CCRF) undergoing maintenance hemodialysis (HD). Methods: We examined TTV DNA in serum of HD-undergoing patients and healthy controls using the nested polymerase chain reaction. Results: TTV DNA was detected in 15 (20.0%) of 75 HD-undergoing patients and 10 (13.2%) of 76 healthy controls (p$gt;0.05). The prevalence of TTV did not differ according to the duration of HD or transfusion history of the patients. The prevalence of TTV was higher in IgG anti-HBc positive patients than IgG anti-HBc negative patients (27.5% vs. 4.2%, p=0.03). There was no relationship between TTV infection and liver diseases. Conclusions: The prevalence of TTV infection in CRF patients undergoing HD was similar with that of healthy controls. These results suggest that TTV infection may share the route of transmission with HBV infection in adults.

라미부딘과 HBIg 1주일 단기 병합요법은 간이식 후 B형 간염 재발 방지에 HBIg 장기 고용량 투여요법만큼 효과적인가?

김성주,장재권,이석구,도재혁,백승운,최문석,조재원,고광철,이풍렬,이종철,최규완,박상종,이준혁,김재준,임윤정,안병훈 대한소화기학회 2001 대한소화기학회지 Vol.37 No.1

Background/Aims : The aim of this study was to evaluate whether the regimen consisted of lamivudine and one-week HBIg for HBV prophylaxis after liver transplantation is as effective as long-term therapy of high dose HBIg. Methods: Sixty-one patients with HBV infection were randomly divided into two groups: HBIg group of 31 patients and combination group of 30 patients. In the HBIg group, HBIg was given according to the standard dosing schedule. In the combination group, lamivudine was given indefinitely from at least 4 weeks before transplantation, and 10,000 IU of HBIg was given during anhepatic phase and 6 consecutive days. Results: The two groups were not different in HBeAg and HBV DNA positivity. In the HBIg group, the median follow-up of 20 long-term survivors was 12.7 months (range: 4.0 - 48.2) and that of 23 survivors in the combination group was 22.3 months (4.2 - 42.2). Hepatitis B recurred in a patient of the HBIg group and 2 of the combination group. The recurrence-free survival rate of long-term survivors was 66.7% (95% C.I., 39.5% - 93.9%) in the HBIg group and 76.0% (58.6% - 93.4%) in the combination group after 40 months. Conclusions: The combined therapy of lamivudine and one-week HBIg has an effect equivalent to long-term therapy of high dose HBIg in HBV prophylaxis after liver transplantation at a much lower cost.

열선 화학 기상 증착법에 의한 실리콘 박막 및 태양전지 특성

김상균(Kim, Sang-Kyun),이정철(Lee, Jeong Chul),전상원(Jeon, Sang Won),임충현(Lim, Chung Hyun),안세진(Ahn, Sae Jin),윤재호(Yun, Jae Ho),김석기(Kim, Seok Ki),송진수(Song, Jinsoo),박성주(Park, S-J),윤경훈(Yoon, Kyung Hoon) 한국신재생에너지학회 2005 한국신재생에너지학회 학술대회논문집 Vol.2005 No.06

최근 열선 화학 기상 증착법(HWCVD)은 낮은 온도에서 TFT용 Poly Si 중착을 할 수 있다는 점과 실리콘 박막을 빠른 속도로 증착할 수 있다는 점에서 각광을 받고 있다. 본 연구에서는 HWCVD를 이용하여 태양전지를 제조하고 그 특성을 평가하였다. 조건에 따른 실리콘 박막의 특성 변화를 알기 위해 corning glass 및 실리콘 wafer에 다양한 조건에서 단위 박막(intrinsic layer)을 증착하였고 이 결과를 바탕으로 p/i/n 구조의 태양전지를 제조하였다. Ta 열선 온도는 1700-2000도였고 가스 원료인 SiH₄와 수소의 비율을 조절하면서 그 영향을 관찰하였다. 태양전지의 경우 p충과 n충은 PECVD로 증착하였으며 단위박막 및 태양전지 i충 증착시 기판과 열선간의 거리는 7cm, 기판 온도는 200?C와 250?C로 고정하였고 작업압력은 30mTorr였다. 단위 박막 특성 평가를 위해 암/광 전도도, SEM, Raman Scattering, FT-IR등을 사용하였으며 태양전지 특성 평가를 위해 I-V 및 Spectral response를 측정하였다. 열선 온도가 증가함에 따라 증착속도 및 결정화 분율은 증가하였다. 특히 비정질에서 결정질로 전이되는 구간은 매우 좁았으며 여러 분석 방법에서 일치되는 결과를 보였다. SiH₄ 유량이 늘어날수록 비정질이 결정질로 바뀌는 열선 온도가 증가하였으며 기판 온도가 낮을 경우 또한 결정으로 바뀌는 열선 온도가 증가하였다. 태양전지의 경우 열선 온도가 증가함에 따라 V_{oc} 및 W가 낮아졌으며 J_{sc}, 는 증가하는 경향을 보였으며 결정질 비율이 증가하는 것을 관찰할 수 있었다. 이러한 경향은 quantum efficiency 결과에서도 확인할 수 있었다.

Low-temperature co-sintering technique for the fabrication of multi-layer functional ceramics for solid oxide fuel cells

Seok, C.,Moon, J.,Park, M.,Hong, J.,Kim, H.,Son, J.W.,Lee, J.H.,Kim, B.K.,Lee, H.W.,Yoon, K.J. Elsevier Science Publishers 2016 Journal of the European Ceramic Society Vol.36 No.6

The low-temperature co-sintering technique for the fabrication of the multi-layered electrolyte supported on a planar anode substrate is demonstrated for solid oxide fuel cells (SOFCs). A NiO/gadolinia-doped ceria (GDC) anode substrate is fabricated using tape casting and lamination processes, and yttria-stabilized zirconia (YSZ) bottom electrolyte and GDC top electrolyte layers are sequentially screen-printed, followed by co-sintering at 1230<SUP>o</SUP>C. The electrolyte layers are successfully densified at an extremely low processing temperature by promoting the sinterability of the individual components, and a continuously graded electrolyte structure is constructed to suppress the delamination of the electrolyte films. Based on the camber analysis, the cell structure is optimized to minimize the structural distortion and eliminate the processing defects. The low-temperature co-sintering technique presented in this study is expected to widen the material selection and resolve the compatibility issues associated with high-temperature processing for the fabrication of SOFCs.

Effect of Occupational Health and Safety Management System on Work-Related Accident Rate and Differences of Occupational Health and Safety Management System Awareness between Managers in South Korea's Construction Industry

Yoon, Seok J.,Lin, Hsing K.,Chen, Gang,Yi, Shinjea,Choi, Jeawook,Rui, Zhenhua Occupational Safety and Health Research Institute 2013 Safety and health at work Vol.4 No.4

Background: The study was conducted to investigate the current status of the occupational health and safety management system (OHSMS) in the construction industry and the effect of OHSMS on accident rates. Differences of awareness levels on safety issues among site general managers and occupational health and safety (OHS) managers are identified through surveys. Methods: The accident rates for the OHSMS-certified construction companies from 2006 to 2011, when the construction OHSMS became widely available, were analyzed to understand the effect of OHSMS on the work-related injury rates in the construction industry. The Korea Occupational Safety and Health Agency 18001 is the certification to these companies performing OHSMS in South Korea. The questionnaire was created to analyze the differences of OHSMS awareness between site general managers and OHS managers of construction companies. Results: The implementation of OHSMS among the top 100 construction companies in South Korea shows that the accident rate decreased by 67% and the fatal accident rate decreased by 10.3% during the period from 2006 to 2011. The survey in this study shows different OHSMS awareness levels between site general managers and OHS managers. The differences were motivation for developing OHSMS, external support needed for implementing OHSMS, problems and effectiveness of implementing OHSMS. Conclusion: Both work-related accident and fatal accident rates were found to be significantly reduced by implementing OHSMS in this study. The differences of OHSMS awareness between site general managers and OHS managers were identified through a survey. The effect of these differences on safety and other benefits warrants further research with proper data collection.

Effect of Occupational Health and Safety Management System on Work-Related Accident Rate and Differences of Occupational Health and Safety Management System Awareness between Managers in South Korea's Construction Industry

Seok J. Yoon,Hsing K. Lin,Gang Chen,Shinjea Yi,최재욱,Zhenhua Rui 한국산업안전보건공단 산업안전보건연구원 2013 Safety and health at work Vol.4 No.4

BackgroundThe study was conducted to investigate the current status of the occupational health and safety management system (OHSMS) in the construction industry and the effect of OHSMS on accident rates. Differences of awareness levels on safety issues among site general managers and occupational health and safety (OHS) managers are identified through surveys. MethodsThe accident rates for the OHSMS-certified construction companies from 2006 to 2011, when the construction OHSMS became widely available, were analyzed to understand the effect of OHSMS on the work-related injury rates in the construction industry. The Korea Occupational Safety and Health Agency 18001 is the certification to these companies performing OHSMS in South Korea. The questionnaire was created to analyze the differences of OHSMS awareness between site general managers and OHS managers of construction companies. ResultsThe implementation of OHSMS among the top 100 construction companies in South Korea shows that the accident rate decreased by 67% and the fatal accident rate decreased by 10.3% during the period from 2006 to 2011. The survey in this study shows different OHSMS awareness levels between site general managers and OHS managers. The differences were motivation for developing OHSMS, external support needed for implementing OHSMS, problems and effectiveness of implementing OHSMS. ConclusionBoth work-related accident and fatal accident rates were found to be significantly reduced by implementing OHSMS in this study. The differences of OHSMS awareness between site general managers and OHS managers were identified through a survey. The effect of these differences on safety and other benefits warrants further research with proper data collection.

Evolution of the shape of the conducting channel in complementary resistive switching transition metal oxides

Yoon, K.,Song, S.,Seok, J.,Yoon, J.,Park, T.,Kwon, D.,Hwang, C. Royal Society of Chemistry 2014 Nanoscale Vol.6 No.4

Ultimate control of the defect distribution and local conduction path in a bipolar resistive switching (BRS) Pt/TiO2/Pt sample, which was in a unipolar reset state, is provided by means of voltage pulsing and the resulting time-transient current analysis. The limited amount of oxygen vacancies in this system allowed reversibly switching-diode-like current-voltage curves, which was also confirmed in another Magneli-phase-containing Pt/WO3/Pt sample. Such careful control of the defect distribution allowed the achievement of a complementary resistive switching (CRS) curve even from a single switching layer. The unlimited vacancy source in the Pt/TiO2/TiO2-x/Pt sample did not allow the switching-diode type and the CRS behavior. The data retention of the on-state in the BRS was critically dependent on the shape of the rejuvenated conduction channel. The required time to lead to the rejuvenation of the conducting channel was similar to 70-100 ns when the threshold voltage for the BRS set of similar to-1 V was applied.