Ge-Se-Te계 칼코지나이드 유리의 결정 생성 현상 및 특성

이용우,허종,Lee, Yong-Woo,Heo, Jong 한국세라믹학회 1995 한국세라믹학회지 Vol.32 No.2

Chalcogenide glasses with compositions of Ge10Se90-xTex(X=0~50 at.%) were prepared in order to investigate the effects of Te substitution on the transmission characteristics of Ge-Se glasses in the 8~12 ${\mu}{\textrm}{m}$ wavelength region. Absorption coefficients were observed to decrease with Te addition, indicating the improved transmission capabilities of Ge-Se-Te glasses as compared to binary Ge-Se glasses. XRD analysis of crystallized glasses suggested the formation of weaker Se-Te and/or Te-Te bonds with addition of Te substituting for Se in stronger Se-Se bonds. Incorporation of Te in excess of 20at% resulted in the formation of hexagonal Te phases when crystallized. It is speculated that the presence of Te-Te bonds with highly metallic bond character resulted in the enhanced crystallization tendencies of glasses. Fromation of Te-rich chains through gradual replacement of Se-Se with Se-Te and/or Te-Te bonds was further supported by decreases in glass transition and crystallization temperatures.

회원작품-포도원교회

이용우,Lee, Yong-Woo 대한건축사협회 2007 建築士 Vol.2007 No.2

회원작품-학동주택

이용우,Lee, Yong-Woo 대한건축사협회 2007 建築士 Vol.2007 No.8

Alcaligenes eutrophus 균주의 성장과 Ploy-${\beta}$-hydroxybutyrate 생합성에 대한 속도론

이용우,유영제,Lee, Yong-Woo,Yoo, Young-Je 한국미생물 · 생명공학회 1991 한국미생물·생명공학회지 Vol.19 No.2

It is very important to have a good kinetic model which considers the effects of both ammonium and glucose for the control and optimization of the poly-${\beta}$-hydroxybutyrate (PHB) fermentation. A kinetic model for the growth of Alcaligenes eutrophus and the biosynthesis of PHB under both ammonium and glucose limitation was proposed. Growth rate of residual biomass was expressed as a function of concentrations of residual biomass, glucose and ammonium having glucose inhibition. PHB production rate was expressed as a function of concentrations of residual biomass, glucose, ammonium and PHB content having ammonium and product inhibitions. Novel approaches were made to estimate the parameters in the model equations which considered two limiting substrates. Model parameters were evaluated by graphical and simplex methods. The proposed kinetic model fitted the data very well.

광합성색소 분석을 통한 광양만 갯벌 퇴적물 중 저서미세조류의 계절변화

이용우,최은정,김영상,강창근,Lee, Yong-Woo,Choi, Eun-Jung,Kim, Young-Sang,Kang, Chang-Keun 한국해양학회 2009 바다 Vol.14 No.1

광양만 조간대 갯벌에 서식하는 저서미세조류와 해수 중 식물플랑크톤의 생체량과 군집조성의 계절변동 양상을 밝히기 위하여, 2002년 1월부터 11월까지 매월 high-performance liquid chromatograph(HPLC)를 이용한 광합성색소(photosynthetic pigments) 분석을 실시하였다. 광합성색소 분석결과 규조류(diatoms)의 주요 지표색소인 fucoxanthin, diadinoxanthin 그리고 diatoxanthin이 퇴적물과 상부 해수에서 연중 우점하여 나타났다. 이들을 제외한 다른 색소들은 상대적으로 낮은 농도를 보였다. 깊이 0.5 cm까지의 표층퇴적물에서 측정한 chlorophyll ${\alpha}$ 농도는 3.44${\sim}$169 mg $m^{-2}$의 범위로 연평균 농도는 상부, 중부 그리고 하부 갯벌 퇴적물에서 각각 $68.4{\pm}45.5,\;21.3{\pm}14.3,\;22.9{\pm}15.6mg\;m^{-2}$로 나타났다. 반면 퇴적물 상부 수주 전체 수심(2.6 m)에 대해 적산한 chlorophyll ${\alpha}$ 농도는 1.66(11월)${\sim}$11.7(7월) mg $m^{-2}$의 농도 범위로 평균 $6.96{\pm}3.04mg\;m^{-2}$를 나타내었다. 이로부터 갯벌 퇴적물 내에 존재하는 저서미세조류의 농도는 해수 중 존재하는 식물플랑크톤의 농도보다 3${\sim}$10배 정도 높은 것으로 추산되었다. 퇴적물과 상부 해수 중 미세조류의 농도에서 유사한 월별변화와 군집조성은 재부유된 저서미세조류가 광양만 해수 중 식물플랑크톤 생체량의 상당부분을 설명할 수 있음을 시사하였다. 따라서 이들 저서미세조류는 갯벌 생물뿐만 아니라 재부유에 의한 수송을 통하여 인근 연안 생태계의 생물군에 대한 중요한 영양원 역할을 할 수 있다는 점에서 이들의 거동에 대한 지속적인 관찰이 요구된다. Seasonal variations of microalgal biomass and community composition in both the sediment and the seawater were investigated by HPLC pigment analysis in an estuarine muddy sandflat of Gwangyang Bay from January to November 2002. Based on the photosynthetic pigments, fucoxanthin, diadinoxanthin, and diatoxanthin were the most dominant pigments all the year round, indicating that diatoms were the predominant algal groups of both the sediment and the seawater in Gwangyang Bay. The other algal pigments except the diatom-marker pigments showed relatively low concentrations. Microphytobenthic chlorophyll ${\alpha}$ concentrations in the upper layer (0.5 cm) of sediments ranged from 3.44 (March at the middle site of the tidal flat) to 169 (July at the upper site) mg $m^{-2}$, with the annual mean concentrations of $68.4{\pm}45.5,\;21.3{\pm}14.3,\;22.9{\pm}15.6mg\;m^{-2}$ at the upper, middle, and lower tidal sites, respectively. Depth-integrated chlorophyll ${\alpha}$ concentrations in the overlying water column ranged from 1.66 (November) to 11.7 (July) mg $m^{-2}$, with an annual mean of $6.96{\pm}3.04mg\;m^{-2}$. Microphytobenthic biomasses were about 3${\sim}$10 times higher than depth-integrated phytoplankton biomass in the overlying water column. The physical characteristics of this shallow estuarine tidal flat, similarity in taxonomic composition of the phytoplankton and microphytobenthos, and similar seasonal patterns in their biomasses suggest that resuspended microphytobenthos are an important component of phytoplankton biomass in Gwangyang Bay. Therefore, considering the importance of microphytobenthos as possible food source for the estuarine benthic and pelagic consumers, a consistent monitoring work on the behavior of microphytobenthos is needed in the tidal flat ecosystems.

HPLC를 이용한 광합성색소 분석과 CHEMTAX 프로그램을 이용한 식물플랑크톤 군집조성 연구

이용우,박미옥,김윤숙,김성수,강창근,Lee, Yong-Woo,Park, Mi-Ok,Kim, Yoon-Suk,Kim, Seong-Su,Kang, Chang-Keun 한국해양학회 2011 바다 Vol.16 No.3

High-Performance Liquid Chromatograph(HPLC)를 이용하여 식물플랑크톤의 광합성색소를 분석한 결과를 토대로 CHEMTAX 프로그램을 이용하여 식물플랑크톤 군집조성을 추정하는 방법이 많이 이용되고 있다. CHEMTAX 프로그램은 식물플랑크톤 군집별(class level)로 체내에 존재하는 주요색소의 chlorophyll a에 대한 상대적인 비 값을 기초로 분석을 한다 본 연구는 국내 해역에서 분리한 식물플랑크톤 군집별 주요 종들이 가지는 광합성색소의 상대적인 비 값을 파악하고 이 자료를 기초로 남해안에 위치한 여자만과 가막만에서 측정한 광합성색소 분석결과에 대해서 CHEMTAX 프로그램을 이용하여 식물플랑크톤의 군집조성을 파악하였다. 국내해역에 존재하는 같은 군집종들 사이에서도 주요색소의 상대적인 비 값은 차이를 보였으며, 국외의 다른 해역에서 제시된 상대적인 비 값과도 상당한 차이를 보였다. 본 연구에서 얻은 비 값을 기초로 식물플랑크톤 군집조성을 분석한 결과, 다른 해역에서 제시된 비 값을 이용하여 분석한 결과와 유의한 차이를 보였다. 우점하는 군집(bacillariophyceae와 dinophytes)에 대해서는 5% 이내에서 차이를 보였으며, 비록 chlorophyll a에 대해서 낮은 기여도를 보이지만 pico와 nano 크기의 군집들(cyanophytes와 prasinophytes)에서는 상당한 차이(2배 이상)를 보였다. 비록 HPLC-CHEMTAX 분석방법은 식물플랑크톤 군집조성 연구에 유용하게 이용되고 있지만, 보다 정확한 결과와 식물플랑크톤의 생리, 생태를 이해하기 위해서는 연구해역에 존재하는 식물플랑크톤 종들에 대한 주요색소의 상대적인 비 값에 대한 연구가 계속적으로 진행되어야 할 것으로 판단된다. Many studies of the phytoplankton community structure have been conducted using the CHEMTAX program on the basis of the photosynthetic pigment concentrations measured by a HPLC (High-Performance Liquid Chromatography) technique. The CHEMTAX program determines the contribution of each phytoplankton class to total phytoplankton biomass (chlorophyll a) based on the ratios of marker pigment to chlorophyll a of phytoplankton group. In this study, the marker pigment/chlorophyll a ratios were investigated in phytoplankton species isolated from marine waters around the Korean peninsula. These results were used as the input pigment ratios of the CHEMTAX program to investigate phytoplankton community structure in Korean coastal waters (Yeoja and Gamak Bay). There were significant differences in the ratios of marker pigment to chlorophyll a among the different species within the same algal class. There was a significant difference between the values of our ratios and the previously used ratios in other regions of the world. When phytoplankton community composition was calculated using our initial ratios in Yeoja and Gamak Bay, our results were significantly different from the results calculated on the basis of initial ratios of marker pigment in phytoplankton suggested in other marine waters. The estimates of the contributions of the major algal groups (bacillariophyceae and dinophytes) to total chlorophyll a varied within 5% depending on the initial ratios chosen. The variations of estimates for the pico- and nanoplankton (cyanophytes and prasinophytes), which have relatively low contributions to total chlorophyll a, were higher than those for major algal group. Although the HPLC-pigment measurements combined with CHEMTAX analysis are useful for identifying and qualifying phytoplankton community structure, further researches for the pigment ratios of the dominant phytoplankton species presenting in a given area are also needed.

무릎 연골 두께 아틀라스를 통한 손상 평가 기법

이용우,안천수,신지태,Lee, Yong-Woo,Bui, Toan Duc,Ahn, Chunsoo,Shin, Jitae 대한의용생체공학회 2015 의공학회지 Vol.36 No.2

Osteoarthritis is the most common chronic joint disease in the world. With its progression, cartilage thickness tends to diminish, which causes severe pain to human being. One way to examine the stage of osteoarthritis is to measure the cartilage thickness. When it comes to inter-subject study, however, it is not easy task to compare cartilage thickness since every human being has different cartilage structure. In this paper, we propose a method to assess cartilage defect using MRI inter-subject thickness comparison. First, we used manual segmentation method to build accurate atlas images and each segmented image was labeled as articular surface and bone-cartilage interface in order to measure the thickness. Secondly, each point in the bone-cartilage interface was assigned the measured thickness so that the thickness does not change after registration. We used affine transformation and SyGN to get deformation fields which were then applied to thickness images to have cartilage thickness atlas. In this way, it is possible to investigate pixel-by-pixel thickness comparison. Lastly, the atlas images were made according to their osteoarthritis grade which indicates the degree of its progression. The result atlas images were compared using the analysis of variance in order to verify the validity of our method. The result shows that a significant difference is existed among them with p < 0.001.

색소분석을 통한 곰소만 내 해수와 퇴적물 중 미세조류 생체량과 군집구조의 시공간적 변화

이용우,박미옥,윤지현,허성범,Lee, Yong-Woo,Park, Mi-Ok,Yoon, Ji-Hyun,Hur, Sung-Bum 한국해양학회 2012 바다 Vol.17 No.2

만의 대부분이 조간대(약 75%)인 전라북도 곰소만 내 해수와 퇴적물 중 미세조류의 생체량과 군집조성의 월 변화를 비교하기 위해서 1999년 2월부터 2000년 1월까지는 매월, 2000년 2월부터 12월까지는 격월로 high-performance liquid chromatograph(HPLC)를 이용하여 광합성색소 분석을 실시하였다. 또한 해수 중 미세조류의 군집구조를 조절하는 환경요인을 조사하기 위해서 수온, 염분, 영양염류, 용존산소, 화학적산소요구량을 분석하였다. 해수 중 미세조류의 월별 분포는 대체로 담수의 유입으로 인한 영양염류의 공급이 많은 시기에 높은 생체량(chlorophyll a)을 보였다. 퇴적물 중 저서미세조류의 생체량은 국내외 다른 갯벌지역에 비해서 상대적으로 낮았으며, 단위 면적당 적분한 해수 중 미세조류의 생체량에 비해서 2-3배 낮게 나타났다. 해수와 퇴적물 중 미세조류의 색소분석 결과, 규조류의 주요색소인 fucoxanthin 농도가 가장 높았으며, fucoxanthin과 chlorophyll a의 월 변화가 유사한 양상을 보여 곰소만 내 갯벌과 해수 중 미세조류는 규조류가 우점하는 것으로 판단된다. 그러나 조하대 표층 해수 중 미세조류 생체량(chlorophyll a)의 월 변화는 갯벌에 서식하는 저서미세조류 생체량의 월 변화와 다른 양상을 보였으며, 현미경 관찰을 통한 해수 중 미세조류의 종조성 분석 결과, 저서미세조류의 우점종인 저서성 규조류는 거의 관찰되지 않았다. 본 연구결과는 곰소만 갯벌에서 재부유되어 조하대로 공급되는 저서미세조류가 조하대 표층 생태계에 서식하는 생물에게 먹이원으로서의 기여도는 상대적으로 낮다는 것을 시사한다. 갯벌에서 재부유되어 조하대로 공급되는 미세조류의 정확한 평가와 함께 조하대에서 이들의 수직, 수평 거동과 관련된 심도 깊은 연구가 필요할 것으로 판단된다. To compare monthly variations of phytoplankton biomass and community composition between in seawater and sediment of the Gomso Bay (tidal flat: approximately 75%), the photosynthetic pigments were analyzed by HPLC every month in 1999 and every two months in 2000. Ambient physical and chemical parameters (temperature, salinity, nutrients, dissolved oxygen, and chemical oxygen demand) were also examined to find the environmental factors controlling structure of phytoplankton community. The temporal and spatial variations of chlorophyll a concentration in seawater were correlated well with the magnitude of freshwater discharge from land. The biomass of microphytobenthos at the surface sediments was lower than that in other regions of the world and 2-3 times lower than phytoplankton biomass integrated in the seawater column. Based on the results of HPLC pigment analysis, fucoxanthin, a marker pigment of diatoms, was the most prominent pigment and highly correlated with chlorophyll a in seawater and sediment of the Gomso Bay. These results suggest that diatoms are the predominant phytoplankton in seawater and sediment of the Gomso Bay. However, the monthly variation of chlorophyll a concentration in seawater at the subtidal zone was not a good correlation with that in sediment of the Gomso Bay. Although pelagic plankton was identified in seawater by microscopic examination, benthic algal species were not found in the seawater. These results suggest that contribution from the suspended microphytobenthos in the tidal flat to the subtidal zone of the Gomso Bay may be low as a food source to the primary consumer in the upper water column of the subtidal zone. Further study needs to elucidate the vertical and horizontal transport magnitude of the suspended microphytobenthos in the tidal flat to the subtidal zone.

( 1 ) 저밀도 지방단백질 수용체 생합성 억제완화에 미치는 Gisenoside 의 영향

이용우,구자현,주충노 ( Yong Woo Lee,Ja Hyun Koo,Chung No Joo ) 생화학분자생물학회 1987 BMB Reports Vol.20 No.4

The effect of saponin fraction from Panax ginseng C. A. Meyer and the purified ginsenosides-Rb₁, -Rb₂, -Re, -Rg₁ on LDL receptor biosynthesis in high cholesterol fed rat has been investigated. The cholesterol level of blood serum of high cholesterol diet-ginsenoside administered rat was greatly lower than that of high cholesterol diet administered rat (control) suggesting that the ginsenosides have hypocholesterolemic action. Analysis of LDL receptor from various organs such as liver, kidney, adrenal cortex and testis showed that the population of LDL receptors were significantly increased in the above organs suggesting that the hypocholesterolemic action might be brought about by the increase of LDL receptor.

회원작품 - 남서울교회

이용우,Lee, Yong-Woo 대한건축사협회 2010 建築士 Vol.2010 No.9