• Bulletin of the Korean Chemical Society
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• 제23권2호
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• pp.225-228
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• 2002

Amorphous $Ga_2O_3$ films have been grown on Si(100) substrates by metal organic chemical vapor deposition (MOCVD) using gallium isopropoxide, $Ga(O^iPr)_3$, as single precursor. Deposition was carried out in the substrate temperature range 400-800 $^{\circ}C$. X-ray photoelectron spectroscopy (XPS) analysis revealed deposition of stoichiometric $Ga_2O_3$ thin films at 500-600 $^{\circ}C$. XPS depth profiling by $Ar^+$ ion sputtering indicated that carbon contamination exists mostly in the surface region with less than 3.5% content in the film. Microscopic images of the films by scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed formation of grains of approximately 20-40 nm in size on the film surfaces. The root-mean-square surface roughness from an AFM image was ${\sim}10{\AA}$. The interfacial layer of the $Ga_2O_3$/Si was measured to be ${\sim}35{\AA}$ thick by cross-sectional transmission electron microscopy (TEM). From the analysis of gaseous products of the CVD reaction by gas chromatography-mass spectrometry (GC-MS), an effort was made to explain the CVD mechanism.

• Journal of Chest Surgery
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• 제31권11호
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• pp.1023-1030
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• 1998

연구배경 : 인체내 이식된 생체조직들은 석회화 변성으로 인해 그 내구성이 단축된다. 이러한 조직들을 이식하기전에 글루타르알데하이드(GA)로 고정후 sulphonated polyethyleneoxide(PEO-SO3)를 결합시키고 또한 조직내 의 잔유 알데히드기를 제거함으로써 석회화에 대한 내구성을 향상시킬 수 있다 재료 및 방법 : PEO-SO3 처리법과 잔유 알데히드기 제거의 석회화 방지 효과를 알아보기 위하여 GA 고정 후 PEO-SO3로 처리한 소 심낭 첨포를 잔유 알데히드기 제거를 위해 무균 생리식염수에 보존한 saline 군과 0.65% GA 용액 에 보존한 GA군, 그리고 이미 상품화되어 임상에서 사용되고 있는 product군을 8마리 개의 경동맥과 대퇴동 맥 및 복막에 이식하여 6주 후 적출하여 칼슘량 및 병리조직 소견에 대해 알아보았다. 결과 : 경동맥에서 채취한 조직첨포의 칼슘량은 saline군에서 GA군과 product군에 비해 유의하게 적었다 (saline; 2.89$\pm$0.31 vs. GA; 6.14$\pm$1.08 vs. product; 22.82$\pm$5.00 mg/g; p< .05). 대퇴동맥과 복막 이식 첨포에서의 칼슘량 또한 saline군에서 다른 두 군에 비해 가장 적었으나 통계적인 유의성은 없었다. 한편 병리조직 검사에서는 GA군에서 다른 두 군에 비해 조직의 석회화로 인한 변성 파괴가 심하였다. 결론 : 본 연구에서 소 심낭 조직 첨포와 결합한 PEO-SO3는 석회화를 감소시키고 또한 조직내 잔유 알데히드기 를 생리식염수로 세척하여 제거함으로써 항석회화 효과를 증가시킬 수 있었다. 결론적으로 PEO-SO3로 처리한 소 심낭 조직은 석회화 변성에 대한 강한 저항성을 보임으로써 심혈관 첨포나 인공 조직 판막 개발 에 도움를 줄 수 있을 것이다.

• 한국결정성장학회지
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• 제15권6호
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• pp.234-238
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• 2005

[ $Cl_2/Ar$ ] 유도결합 플라즈마(ICP)내의 플라즈마 조성, 이온 flux 및 이온 에너지가 $La_3Ga_5SiO_{14}$ 단결정 wafer의 식각속도, 표면 양상 및 화학량론적 조성에 미치는 영향을 조사하였다. 비교적 높은 ICP source power$({\sim}1000W)$ 또는 높은 $Cl_2$ gas 유량 비율 조건으로부터 최고 약 $1600{\AA}/min$의 실용적이고 조절이 용이한 식각속도를 확보하였다. 식각된 $La_3Ga_5SiO_{14}$ 표면은 식각 이전과 비슷하거나 더 낮은 표면 조도 특성을 나타내었으며 식각 공정 전, 후 표면의 화학량론적 조성에 있어서의 변화는 없는 것으로 조사되었다.

• 한국식품위생안전성학회지
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• 제13권4호
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• pp.377-382
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• 1998

항산화효과, 항돌연변이효과, 콜레스테롤농도 상승억제작용이 우수한 것으로 알려진 차추출물의 주요성분을 분리 정량하기 위하여 각 발효정도에 따른 분류 및 녹차의 채엽시기별에 따라 녹차 1번차 녹차2번차 녹차 3번차, 우롱차 및 홍차 등에 대한 일반성분, 아미노산, Vit.C, Vit. E, ${\beta}-carotene$, 카테킨류, 카페인, 데오브로마인 및 데오필린 등을 분석하고 특히 항산화성분인 카테킨류의 항산화효과 및 항돌연변이 효과의 연구에 기초자료로 이용하고자 하였다. 녹차 I, II, III, 우롱차 및 홍차의 일반 성분중 조지방함량은 각각 1.1, 2.5, 4.9, 0.8 및 1.2% 이었으며, 총 아미노산함량은 녹차I>녹차II>녹차III의 순이었고 대부분의 아미노산은 차 성분의 유일한 아미노산인 theanine이 차지하였다. 녹차 I, II, III, 우롱차 및 홍차에 함유된 Vit. C함량은 각각 101.6, 87.5, 95.9, 99.1 및 108.0 mg%이었으며, ${\beta}-carotene$ 함량은 각각 270, 268, 481, 80 및 181 ppm이었고, Vit. E 함량은 ${\alpha}-tocopherol$이 대부분을 차지하였으며 ${\beta}-$ 및 ${\delta}-tocopherol$은 모두 검출되지 않았다. 한편, 총카테킨류의 함량은 각각 10.5, 10.4, 7.2, 8.4 및 1.8%로 총카테킨류중 EGCG의 함량이 가장 높았다. 카테킨류 중 EGC의 함량은 녹차I>녹차III>녹차II>우롱차>홍차의 순으로 녹차I이 가장 높았으며, EGCG와 ECG의 함량은 우롱차>녹차I>녹차II>녹차III>홍차의 순으로 우롱차가 가장 높았다. 또한 GA함량은 0.01, 0.02, 0.05, 0.13 및 0.31%로 홍차에 가장 많은 것으로 나타났으며, 카페인 및 데오브로마인 함량도 홍차의 경우가 가장 높았으나 데오필린 함량은 녹차I이 가장 높게 나타났다.

• Journal of Chest Surgery
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• 제46권1호
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• pp.1-13
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• 2013

Background: Glutaraldehyde (GA) is a widely used cross-linking agent for improving mechanical properties and resistance to enzymatic degradation of collagenous tissue, but it has several drawbacks such as calcification and cytotoxicity. The aim of this study was to find the alternative effective cross-linking methods to GA. Materials and Methods: Bovine pericardium was processed with GA with ethanol+octanol and glycine detoxification, and polyethylene glycol (PG) space filler, dimethyl 3,3'-dithiobispropionimidate (DTBP), 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) treatment, and the physical fixation of ultraviolet irradiation were done. The biologic material properties of variously treated pericardial tissues were assessed by biochemical, mechanical and histological tests. Treated pericardial tissues were also implanted subcutaneously or intramuscularly into the rabbit for 10 weeks to assess the xenoreactive antibody response of immunoglobulin G and M, their anti-calcification effect. Results: The biochemical and mechanical properties of EDC fixed pericardial tissues were comparable to the GA fixed tissue. The cytotoxicity was lowest in space filler treated GA fixed group. In rabbit subcutaneous or intramuscular implantation models, decellularization, space filler, EDC treatment group showed significantly lower calcium content than GA only and DTBP treatment group (p<0.05, analysis of variance). The titer of anti $Gal{\alpha}1-3Gal{\beta}1$-4GlcNAc-R antibodies did not change in the postimplantation serial enzyme-linked immunosorbent assay. Hematoxylin and eosin and von Kossa staining showed that decellularization, space filler, EDC, and ultraviolet treatment had less inflammatory cell infiltration and calcium deposits. Conclusion: The decellularization process, PG filler, and EDC treatments are good alternative cross-linking methods compared to GA only fixation and primary amine of DTBP treatment for cardiovascular xenograft preservation in terms of the collagen cross-linking stability and in vivo anti-calcification effects.

• 농업과학연구
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• 제19권1호
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• pp.9-15
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• 1992

성숙기(成熟期)의 기온저하(氣溫低下)로 품질저하(品質低下)를 초래 하는 중부지방(中部地方)의 '풍수(豊水)' 재배(栽培)에 있어서 gibberellin paste의 처리효과(處理效果)가 과실(果實)의 비대생장(肥大生長)과 숙기(熟期) 및 품질(品秩)에 미치는 영향(影響)을 조사(調査)한 결과(結果) 다음과 같은 결과(結果)를 얻었다. 유과기(幼果期)의 $GA_{3+4+7}$ paste 처리(處理)는 GA의 지속적(持續的)인 공급(供給)으로 과실(果實)의 비대(肥大)를 촉진(促進)시킬 뿐 아니라 절대적 생장량(生長量)을 증가(增加)시킬 수 있는 것으로 밝혀졌다. 성숙기(成熟期)에 과육(果肉)의 경도(硬度)가 다소 감소(減少)되었지만 기타의 품질(品秩)에 미치는 영향(影響)은 인정(認定)되지 않았다. 하지만 $GA_3$의 효과(效果)는 인정(認定)되지 않았다. $GA_{3+4+7}$의 처리(處理)는 과실(果實)의 ethylehe 발생(發生)에는 큰 영향(影響)을 미치지 않았지만 지색(地色)의 변화(變化)를 촉진(促進)시켜 성숙기(成熟期)를 3~5일 정도(程道) 앞당길 수 있었다. 따라서 본 연구(硏究)의 결과(結果)는 중부지방(中部地方)의 '풍수(豊水)' 재배(栽培)에 있어 상품성(商品性)이 높은 과실(果實)의 생산기술(生産技術)로 활용(活用)할 수 있을 것으로 기대된다.

• 한국작물학회지
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• 제56권1호
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• pp.94-98
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• 2011

Proximate chemical components (protein, oil, carbohydrate, ash, fiber, and starch) were determined from tubers grown in upland and wetland conditions. The contents of crude protein, oil, carbohydrate, and starch were higher in upland condition than in wetland condition. Eight gibberellins were commonly identified and quantified in leaves and tuber of chufa grown in wetland and upland field during growing season. Gibberellin content was always higher specifically in the leaves and tubers grown in wetland condition than in those grown in upland condition. The current knowledge of gibberellin biosynthesis suggests that the two endogenous bio-active gibberellins both $GA_1$ and $GA_4$ are differently metabolized according to cultural conditions. Major gibberellin biosynthesis route is ascertained dominantly the non C-13 hydroxylation pathway leading $GA_4$ in chufa plants.

• Journal of Chest Surgery
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• 제44권2호
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• pp.99-107
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• 2011

Background: Calcification is the most frequent cause of clinical failure of bioprosthetic tissues fabricated from GA-fixed porcine valves or bovine pericardium. A multi-factorial approach using different mechanisms was recently developed to reduce the calcification of bioprosthetic tissues. The purpose of the present study was to evaluate the synchronized synergism of using L-arginine and $NaBH_4$, compared with ethanol and L-lysine, in glutaraldehyde treated porcine pericardium from the standpoint of calcification and tissue elasticity. Materials and Methods: Porcine pericardium was fixed at 0.625% GA (7 days at room temperature after 2 days at $4^{\circ}C$). An interim step of ethanol (80%; 1 day at room temperature) or L-lysine (0.1 M; 2 days at $37^{\circ}C$) or L-arginine (0.1 M; 2 days at $37^{\circ}C$) was followed by completion of the GA fixation. A final step of NaBH4 (0.1 M; 2 days at room temperature) was followed. Their tensile strength, thickness, and thermal stability were measured. Treated pericardia were implanted subcutaneously into three-week-old Sprague-Dawley rats for 8 weeks. Calcium content was assessed by atomic absorption spectroscopy and histology. Results: L-arginine and $NaBH_4$ pretreatment ($1.81{\pm}0.39$ kgf/5 mm p=0.001, $0.30{\pm}0.08$ mm p<0.001) significantly increased tensile strength and thickness compared with the control ($0.53{\pm}0.34$ kgf/5 mm, $0.10{\pm}0.02$ mm). In a thermal stability test, L-arginine and $NaBH_4$ pretreatment ($84.25{\pm}1.12^{\circ}C$, p=0.023) caused a significant difference from the control ($86.25{\pm}0.00^{\circ}C$). L-lysine and $NaBH_4$ pretreatment ($183.8{\pm}42.6$ ug/mg, p=0.804), and L-arginine and $NaBH_4$ pretreatment ($163.3{\pm}27.5$ ug/mg, p=0.621) did not significantly inhibit calcification compared to the control ($175.5{\pm}45.3$ ug/mg), but ethanol and $NaBH_4$ pretreatment did ($38.5{\pm}37.3$ ug/mg, p=0.003). Conclusion: The combined pretreatment using L-arginine and $NaBH_4$ after GA fixation seemed to increase the tensile strength and thickness of porcine pericardium, fixed with GA. Additionally, it seemed to keep thermal stability. However it could not decrease the calcification of porcine pericardium fixed with GA. $NaBH_4$ pretreatment seemed to decrease the calcification of porcine pericardium fixed with GA, but only with ethanol.

• 환경위생공학
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• 제7권1호
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• pp.87-94
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• 1992

In order to investigate the content of heavy metals in soil according to vertical profiles, 72 soil samples were collected from 4 sampling sites : Ulchiro-2 ga, Dugdo, Sungnaedong, and Amsa- dong. The content of mercury was measured by a mercury analyzer and those of lead, copper and zinc were measured by an atomic absorption spectrophotometer. From the results of this study, it was shown that the content of heavy metals decreased gradually from the surface soil to the 2 m- depth soil. But, there was no difference in the contents of the heavy metals in the 3m, the 4m and the 5m-depth soil.

• 한국전기전자재료학회논문지
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• 제26권9호
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• pp.701-706
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• 2013

We have focused on the conversion efficiency of CIGS thin film solar cell prepared by co-evaporation method as well as the optimization of process condition. The total thickness of back electrode was fixed at 1 ${\mu}m$ and the structural, electric and optical properties of CIGS thin film were investigated by varying the thickness of Mo:Na bottom layer from 0 to 500 nm. From the experimental results, the content of Na was appeared as 0.28 atomic percent when the thickness of Mo:Na layer was 300 nm with compactly densified plate-shape surface morphology. From the XRD measurements, (112) plane was the strongest preferential orientation together with secondary (220) and (204) planes affecting to the crystallization. The lowest roughness and resistivity were 2.67 nm and 3.9 ${\Omega}{\cdot}cm$, respectively. In addition, very high carrier density and hole mobility were recorded. From the optimization of Mo:Na layer, we have achieved the conversion efficiency of 9.59 percent.