Effects of hydrogen plasma treatment on SnO2:F substrates for amorphous Si thin film solar cells

Min-Seung Choi,Young-Ju Lee,Jung-Dae Kwon,Yongsoo Jeong,Ju-Yun Park,강용철,Pung Keun Song,Dong-Ho Kim 한국물리학회 2013 Current Applied Physics Vol.13 No.8

We investigated the effects of hydrogen plasma treatment on the physical and electrical properties of fluorine-doped tin oxide (FTO) films used for amorphous silicon (a-Si) thin film solar cells. A slight increase in carrier concentration by the hydrogen doping effect was observed for the FTO film exposed to the hydrogen plasma for 5 min. For further exposure to the plasma, the chemical reduction became prominent and resulted in deterioration of the electrical and optical properties of the film. XPS analysis revealed that the chemical reduction of SnO2 to Sn metallic state occurs on the surface region. It was found that the defects formed by hydrogen plasma act as recombination centers at the interface between FTO electrode and p-layer of a-Si solar cells. This phenomenon resulted in the deterioration of the cell performance. The averaged conversion efficiency (6.82%) of the cells on pristine FTO hydrogen substrate was decreased to 5.81% for the cells on FTO treated for 5 min, which is mainly attributed to the decrease in short-circuit current density.

치면열구전색제의 조건에 따른 법랑질 결합강도에 관한 연구

이용근,이흥수,이성재,방기숙,최정민,류승호,강민석 대한치과기재학회 1997 대한치과재료학회지 Vol.24 No.1

In this study, the shear bond strengths and accompanying elastic modulus ratio, displacement at bond failure and work up to fracture of pit and fissure sealants to toothe enamel were analyzed by the following variables, those were acid etching, moisture content of the surface of enamel, dentin bonding agent(species and method), thermocycling, saliva contamination. One kind of chemically cured resin based pit and fissure sealant, two kinds of light cured resin based pit and fissure sealants and one kind of glass ionomer based pit and fissure sealant, and two kinds of dentin bonding agents were studied. The buccal surface of extracted premolars were ground flat with # 600 silicone carbide papers, and the ground surface was treated depending on the experimental conditions. After each treatment, each pit and fissure sealant was filled into plastic tube of 3mm diameter, which were laid on the surface of ground enamel surface, and were cured. Sealant bonded teeth specimens were immersed in 37℃ distilled water form 24 hours. The shear bond strength of sealant to enamel surface was measured with Universal testing machine with the cross head speed of 1mm/min. From the obtained load-deflection curves, modulus ratio, bond strength, displacement at bond failure and work up to fracture were analyzed. From this experiment, the following results were obtained : 1. Comparing the results of standard condition(i. e. acid etching, dry surface, no dentin bonding agent and 300 thermocyling), the elastic modulus ratio of chemically cured resinbased pit and fissure sealant was significantly higher than those of other materials(P<0.05), and the bond strength, displacement at bond failure and work up to fracture of glass ionomer based pit and fissure sealant were significantly lower than those of other materials(P<0.05). 2. The results of ANOVA with the variables of type of material, acid etching, moisture condition of the enamel surface, dentin bonding agents were as follows ; 1) variables showed significant main effect on the shear bond strength of pit and fissure sealant to enamel(P<0.01), 2) type of material, acid etching and moisture condition of enamel influenced the bond strength significantly(P<0.01), 3) type and application methods of dentin bonding agents influenced on the bond strength significantly(P<0.05). 3. There were statistically significant correlation between the work up to fracture and the bond strength, and between the work up to fracture and the displacement at bond failure(P<0.01), and in these cases the correlation coefficient was 0.87.

아마추어 마라톤 러너의 호흡순환기능에 관한 연구

이근일,신민철 한국스포츠리서치 2003 한국 스포츠 리서치 Vol.14 No.4

The effects of prolonged endurance training on maximal O₂ uptake in the older people and its determinants were studied, by comparing 1) 7 older endurance athletes(62.5±2.6yrs), 2) 7 middle-aged long distance runners(34.7±3.1yrs), 3) 7 older(61.3±3.8yrs) and 4) 7 middle-aged(33.7±3.1yrs) untrained counterparts, maximal O₂ uptake of the older athletes(50.4±4.1ml/㎏/min) was 67% higher than that of the older untrained men, 28% lower than that of the middle-aged runners, and identical to that of the middle-aged untrained men. The maximal heart rate was 9% lower in the older athletes than in the middle-aged runners(170 vs. 186beats/min). No significant difference in maximal heart rate was observed between the athletes and the nonathletes of the respective age-group. On the other hand, the O₂ pulse at maximal O₂ uptake of the older athletes(0.30±0.03ml/㎏/beats) was 14% lower than that of the middle-aged athletes, but 67 and 15% higher than that of the older and middle-aged untrained men, respectively untrained men, respectively. These results suggest that the lower maximal O₂ uptake of the older endurance athletes is derived from both the lower maximal heart rate and the lower O₂ pulse at maximal O₂ uptake in comparison with the middle-aged athletes.

간경변 환자에서 Oro-cecal Transit Time의 측정

원경준,이준,변유미,조민근,조주연,서정균,김영대,박찬국,김만우 朝鮮大學校 附設 醫學硏究所 2008 The Medical Journal of Chosun University Vol.33 No.2

Background: Neurotransmitter like substances in the gut have been proposed to contribute to the overall portal systemic encephalopathy (PSE). The source of the ammonia in patients with PSE is mainly the small bowel, as a result of the conversion of glutamine in the diet to glutamate and ammonia. PSE is highly responsive to changes in diet, to antibiotic therapy and to ingestion of nondigestible disaccharides such as lactulose. This study was performed to evaluate the relationship between PSE and oro-cecal transit time. In addition, performed to evaluate the effect of severity, cause, complications of liver cirrhosis on oro-cecal transit time. Methods: Between August 2006 and February 2007, 48 cirrhotic patients consecutively was enrolled in study their oro-cecal transit time after informed consent was obtained. A non-invasive hydrogen breath test was used to study oro-cecal transit time (OCTT). Result: The OCTT were delayed in cirrhotic patients with PSE compared without PSE (123.3 ± 42.7 min vs 170.0 ± 58.3 min, p<0.05). OCTT tended to prolongate further as the damage in the liver got worse, nevertheless the result was statistically meaningless (p<0.111). Neither presence of ascites or cause of PSE had any influence on gastrointestinal transit. Conclusions: Cirrhotic patients with PSE have more delayed OCTT than without PSE. Further research is needed to find out the relationship between OCTT and severity of liver cirrhosis.

Structural and biochemical basis for the inhibition of cell death by APIP, a methionine salvage enzyme

Kang, Wonchull,Hong, Se Hoon,Lee, Hye Min,Kim, Na Yeon,Lim, Yun Chan,Le, Le Thi My,Lim, Bitna,Kim, Hyun Chul,Kim, Tae Yeon,Ashida, Hiroki,Yokota, Akiho,Hah, Sang Soo,Chun, Keun Ho,Jung, Yong-Keun,Yang National Academy of Sciences 2014 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.111 No.1

<P>APIP, Apaf-1 interacting protein, has been known to inhibit two main types of programmed cell death, apoptosis and pyroptosis, and was recently found to be associated with cancers and inflammatory diseases. Distinct from its inhibitory role in cell death, APIP was also shown to act as a 5-methylthioribulose-1-phosphate dehydratase, or MtnB, in the methionine salvage pathway. Here we report the structural and enzymatic characterization of human APIP as an MtnB enzyme with a <I>K</I><SUB><I>m</I></SUB> of 9.32 μM and a <I>V</I><SUB><I>max</I></SUB> of 1.39 μmol min<SUP>−1</SUP> mg<SUP>−1</SUP>. The crystal structure was determined at 2.0-Å resolution, revealing an overall fold similar to members of the zinc-dependent class II aldolase family. APIP/MtnB exists as a tetramer in solution and exhibits an assembly with <I>C4</I> symmetry in the crystal lattice. The pocket-shaped active site is located at the end of a long cleft between two adjacent subunits. We propose an enzymatic reaction mechanism involving Glu139* as a catalytic acid/base, as supported by enzymatic assay, substrate-docking study, and sequence conservation analysis. We explored the relationship between two distinct functions of APIP/MtnB, cell death inhibition, and methionine salvage, by measuring the ability of enzymatic mutants to inhibit cell death, and determined that APIP/MtnB functions as a cell death inhibitor independently of its MtnB enzyme activity for apoptosis induced by either hypoxia or etoposide, but dependently for caspase-1-induced pyroptosis. Our results establish the structural and biochemical groundwork for future mechanistic studies of the role of APIP/MtnB in modulating cell death and inflammation and in the development of related diseases.</P>

Effect of spark plasma sintering conditions on the thermoelectric properties of (Bi_0.25Sb_0.75)₂Te₃ alloys

Lim, Sang-Soon,Kim, Ju-Heon,Kwon, Beomjin,Kim, Seong Keun,Park, Hyung-Ho,Lee, Ki-Suk,Baik, Jeong Min,Choi, Won Jun,Kim, Dong-Ik,Hyun, Dow-Bin,Kim, Jin-Sang,Baek, Seung-Hyub Elsevier 2016 JOURNAL OF ALLOYS AND COMPOUNDS Vol.678 No.-

<P><B>Abstract</B></P> <P>As a field-assisted technique, spark plasma sintering (SPS) enables densification of specimens in a very short period of time compared to other sintering techniques. For high performance thermoelectric material synthesis, SPS is widely used to fabricate nanograin-structured thermoelectric materials by rapidly densifying the nanopowders suppressing grain growth. However, the microstructural evolution behavior of thermoelectric materials by SPS, another important process during sintering, has been rarely studied. Here, we explore SPS as a tool to control the microstructure by long-time SPS. Using p-type (Bi<SUB>0.25</SUB>Sb<SUB>0.75</SUB>)<SUB>2</SUB>Te<SUB>3</SUB> thermoelectric materials as a model system, we systematically vary SPS temperature and time to understand the correlations between SPS conditions, microstructural evolution, and the thermoelectric properties. Our results show that the relatively low eutectic temperature (∼420 °C) and the existence of volatile tellurium (Te) are critical factors to determine both microstructure and thermoelectric property. In the liquid-phase sintering regime, rapid evaporation of Te leads to a strong dependence of thermoelectric property on SPS time. On the other hand, in the solid-phase sintering regime, there is a weak dependence on SPS time. The optimum thermoelectric figure-of-merit (Z) of 2.93 × 10<SUP>−3</SUP>/K is achieved by SPS at 500 °C for 30 min. Our results will provide an insight on the optimization of SPS conditions for materials containing volatile elements with low eutectic temperature.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Spark plasma sintering (SPS) is used to synthesize the thermoelectric (Bi<SUB>0.25</SUB>Sb<SUB>0.75</SUB>)<SUB>2</SUB>Te<SUB>3</SUB>. </LI> <LI> Liquid phase and volatile element are a key for the microstructure and thermoelectric property. </LI> <LI> Thermoelectric figure-of-merit of 2.9 × 10<SUP>−3</SUP>/K is achieved at 500 °C for 30 min. </LI> </UL> </P>

소동물 폐종양의 정량적 개선을 위한 내부 움직임 평가

유정우,우상근,이용진,김경민,김진수,이교철,박상준,유란지,강주현,지영훈,정용현,김병일,임상무,Yu, Jung-Woo,Woo, Sang-Keun,Lee, Yong-Jin,Kim, Kyeong-Min,Kim, Jin-Su,Lee, Kyo-Chul,Park, Sang-Jun,Yu, Ran-Ji,Kang, Joo-Hyun,Ji, Young-Hoon,Chung, Y 한국의학물리학회 2011 의학물리 Vol.22 No.3

이 연구에서는 폐종양의 정량적 개선을 위하여 분자체를 이용하여 내부 움직임을 측정하고 평가된 데이터를 기반으로 소동물 PET 영상내의 폐종양을 국소화하고자 하였다. 소동물 폐 영역의 내부 움직임은 방사성물질을 흡착한 분자체를 이용하여 소동물 폐 영역에 부착함으로써 구현하였다. 폐 영역의 내부 움직임 표적으로 사용된 분자체는 약 37 kBq의 Cu-64를 흡착시켜 폐종양을 모사하였다. 소동물 PET 영상은 Siemens Inveon 스캐너를 이용하여 획득하였으며 외부 움직임 데이터는 트리거 생성 장치인 BioVet을 이용하였다. SD-Rat PET 영상은 $^{18}F$-FDG 37 MBq/0.2 mL을 미정맥으로 주사하고 60분 후 20분간 데이터를 획득하였다. 리스트모드 데이터의 각 선응답은 외부 트리거 장치에 의해 획득된 트리거신호를 이용하여 2 bin에서 16 bin으로 사이노그램을 획득하였다. 획득된 사이노그램 데이터는 OSEM 2D 알고리즘을 이용하여 4회의 반복으로 재구성하였다. 종양의 정량적 분석을 위한 PET 영상은 종양을 묘사한 분자체 영역에 관심영역을 설정하고 계수와 SNR 그리고 FWHM을 이용하여 평가하였다. 움직임 표적으로 사용된 분자체의 크기는 $1.59{\times}2.50mm$이었으며, 기준 영상으로 획득한 체외 분자체 수직 및 수평 FWHM은 $2.91{\times}1.43mm$이었다. 정적영상과 4 bin 그리고 8 bin 영상에서의 수직 FWHM은 각각 3.90 mm, 3.74 mm, 3.16 mm이었으며 수평 FWHM은 각각 2.21 mm, 2.06 mm, 1.60 mm이었다. 정적영상, 4 bin, 8 bin, 12 bin 그리고 16 bin의 계수 값은 각각 4.10, 4.83, 5.59, 5.38, 5.31이었다. 정적영상, 4 bin, 8 bin, 12 bin 그리고 16 bin의 SNR은 4.18, 4.05, 4.22, 3.89, 3.58이었다. FWHM은 게이트 수의 증가에 따라 계속 향상됨을 확인하였다. 그러나 계수 값과 SNR은 게이트 수의 증가에 따라 계속 향상되지 않고 특정 bin 수에서 가장 높은 값을 보여 소동물 폐 영역에서의 종양 영상화시 SNR의 손실을 최소화하면서 향상된 계수 값을 얻을 수 있는 게이트 수를 획득하였다. 내부 움직임 측정은 최적화된 종양 국소화 영상을 획득할 수 있으며 외부 움직임 모니터링 시스템을 사용하지 않고 장기별 움직임 예측 모델링을 위한 유용한 방법이 될 것으로 기대된다. The purpose of this study was to estimate internal motion using molecular sieve for quantitative improvement of lung tumor and to localize lung tumor in the small animal PET image by evaluated data. Internal motion has been demonstrated in small animal lung region by molecular sieve contained radioactive substance. Molecular sieve for internal lung motion target was contained approximately 37 kBq Cu-64. The small animal PET images were obtained from Siemens Inveon scanner using external trigger system (BioVet). SD-Rat PET images were obtained at 60 min post injection of FDG 37 MBq/0.2 mL via tail vein for 20 min. Each line of response in the list-mode data was converted to sinogram gated frames (2~16 bin) by trigger signal obtained from BioVet. The sinogram data was reconstructed using OSEM 2D with 4 iterations. PET images were evaluated with count, SNR, FWHM from ROI drawn in the target region for quantitative tumor analysis. The size of molecular sieve motion target was $1.59{\times}2.50mm$. The reference motion target FWHM of vertical and horizontal was 2.91 mm and 1.43 mm, respectively. The vertical FWHM of static, 4 bin and 8 bin was 3.90 mm, 3.74 mm, and 3.16 mm, respectively. The horizontal FWHM of static, 4 bin and 8 bin was 2.21 mm, 2.06 mm, and 1.60 mm, respectively. Count of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.10, 4.83, 5.59, 5.38, and 5.31, respectively. The SNR of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.18, 4.05, 4.22, 3.89, and 3.58, respectively. The FWHM were improved in accordance with gate number increase. The count and SNR were not proportionately improve with gate number, but shown the highest value in specific bin number. We measured the optimal gate number what minimize the SNR loss and gain improved count when imaging lung tumor in small animal. The internal motion estimation provide localized tumor image and will be a useful method for organ motion prediction modeling without external motion monitoring system.

생체분해성 안과제형의 안구내흡수정도와 안독성

민병무,김용백,박근성,송규상,양준묵,이성복,조항진,길숙종,김승영,김학용 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.1

An improved retinal tack can be used to fix the retina in complicated retinal detachment and proliferative vitreoretinopathy. We used the retinal tack made by biodegradable polyglycolic acid, polylactic acid and copolymers. The tacks with polyglycolic acid were placed in the retina the right eyes of 10 rabbits as group 1, with polylactic-polyglycolic acid copolymers as group 2 in each left eyes. We examined the absorption rates and degree of intraocular inflammation at 1 day, 1, 2, 4, and 8 weeks and compared both eyes. The tacks were absorbed with time in both eyes, but more rapid in copolymers. And there was no inflammation in both eyes. Now, this study will be a base on the drug delivery system in intraocular pharmacological and surgical management.

큰느타리버섯 폐배지 이용 배지 제조 및 적정 첨가비율

김민근 외 한국버섯학회 2007 한국버섯학회지 Vol.5 No.2

큰느타리버섯의 재배면적 및 생산량 증가에 따라 많은 양의 폐배지가 발생되고 있다는 사실을 염두에 두고 그 활용도를 높이고자 농가로부터 수거된 폐배지에 대해 성분분석 및 버섯균사에 대한 생육저해 여부를 확인한 뒤 버섯재배에 있어 폐배지의 적정첨가 비율을 결정하고 그에 따른 버섯의 배양특성 및 생육특성을 관찰하였다. 폐배지 성분분석 결과 pH는 새배지에 비해 낮아지는 경향을 보였고 총 질소 함량은 폐배지 첨가비율 많아질수록 높아지는 경향을 나타내었다. 버섯의 배양 및 생육과정 중 배지로 분비된 대사산물에 의해서 일어 날수 있는 버섯 균사생육저해 현상을 조사하기 위해 폐배지 열수추출물을 이용하여 만들어진 고체배지에 버섯 균사를 접종한 결과 폐배지에 의한 버섯균사 저해현상은 확인되지 않았다. 폐배지 첨가에 따른 배양특성을 조사한 결과 첨가량이 증가할수록 균사 생장률은 약간씩 낮아지는 경향을 나타내었으나 50% 이내로 폐배지가 첨가된 조건에서는 일반적인 배양기간 (35일) 내에 배양이 완료된다는 사실을 확인 할 수 있었다. 버섯의 발이특성을 조사한 결과에 있어서도 50% 이내로 폐배지가 첨가된 경우 평균 10일 이내에 발이가 완료되었으나 폐배지 100%로 제조된 배지에서는 정상적으로 발이가 되지 못하였다. 생육특성의 경우 평균 18일 이내에 수확이 완료되었으나 폐배지 첨가량이 30% 이상 일 경우 자실체 수량이 감소하였다. 이상의 결과를 요약하면 큰느타리버섯 재배농가에서 정상적으로 재배되고 발생되는 폐배지의 경우 버섯 잔재물이나 배지 덩어리 및 오염배지와 같은 이물질을 제거한 뒤 10-30% 수준으로 새배지에 첨가하여 재활용 할 경우 정상적인 버섯의 배양 및 생육이 가능하였으며, 이러한 사실은 버섯 재배농가의 재료비 절감에 도움을 줄 수 있을 것을 기대된다. After bottle culture of Pleurotus eryngii, media were taken out the bottle and normally utilized compost. However, nutritional elements were remained in the waste media. This study was carried out to investigate the reusable possibility and the optimal additive rate of waste media in an artificial cultivation of Pleurotus eryngii. The pH had tendency to decrease as the waste media was added from 6.0 to 4.8. Based on the additive rate of 10, 20, 30, 40, and 50%, each treatment waste media was added to new media for culturing Pleurotus eryngii. Among various treatments, the mycelial growth and primordia formation of Pleurotus eryngii were more favorable in the addition of 10-30% waste median than in the addition of 40 and 50%. The yield of its fruiting body was increased slightly in the treatment of 10-30% waste media.

Tricyclic Isoxazole 유도체들의 para-Chloroamphetamine 및 Medetomidine 저해활성 차이에 대한 3D-QSARs 분석

최민성,명평근,성낙도 충남대학교 약학대학 의약품개발연구소 2011 藥學論文集 Vol.26 No.-