• 대한화학회지
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• 제23권1호
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• pp.46-51
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• 1979

Silver triflate와 syn-collidine 존재하에서 3,4,6-tri-O-acetyl-2-phthalimido-${\beta}$-D-glucopyranosyl bromide (2)와 1,2;3,4-di-O-isopropylidene-${\alpha}$-D-galactopyranose (3)를 반응시켜 1,2;3,4-di-O-isopropylidene-6-O-(3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-${\beta}$-D-glucopyranosyl)-${\alpha}$-D-galactopyranose (4)를 $86{\%}$의 수득률로 얻었다. 화합물 4를 hydrazine과 작용시켜 phthalimido기와 acetyl기를 동시에 제거한후, 다시 acetyl화하고 isopropylidene기와 O-acetyl기를 가수분해하면 6-O-(2-acetamido-2-deoxy-${\beta}$-D-glucopyranosyl)-D-galactopyranose (1)가 총수득율 $65.8{\%}$로 얻어졌다. 또한 화합물 4를 변형시켜 특정위치에 hydroxyl기를 가진 몇 가지 유도체도 합성하였다.

• Archives of Pharmacal Research
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• 제22권4호
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• pp.423-427
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• 1999

A study was carried out to evaluate flavonol glycosides in leaves of Symplocarpus renifolius (Araceae). From the water fraction of the MeOH extract, three new flavonol glycosides were isolated along with three known compounds, Kaempferol-3-O-$\beta$-glucopyranosyl-($1{\rightarrow}2$)-$\beta$-D-glucopyranosyl-7-O-$\beta$-D-glucopyranoside, quercetin-3-O-$\beta$-D-glucopyranosy-1-($1{\rightarrow}2$)-$\beta$-D-glucopyranoside, and caffeic acid. The structures of the new flavonol glycosides were elucidated by chemical and spectral analyses a quercetin-3-O-$\beta$-D-glucopyranosyl-($1{\rightarrow}2$)-$\beta$-D-glucopyranosyl-7-O-$\beta$-D-glucopyranoside, isorhamnetin-3-O-$\beta$-D-glucopyranosyl-(1 2)-$\beta$-D-glucopyranosyl-7-O-$\beta$-D-glucopyranosdie, and quercetin-3-O$\beta$-D-glucopyranosyl-($1{\rightarrow}2$)-$\beta$-D-glycopyranosyl-7-O-($6^{IIII}$-trans-caffeoyl)-$\beta$-D-glucopyranoside.

• Natural Product Sciences
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• 제4권4호
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• pp.268-273
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• 1998

Two new triterpenoid saponins, named segetoside D and E, have been isolated from the seeds of Vaccaria segetalis. On the basis of chemical reactions and spectral data, structures of segetoside D and E have been established as: $28-O-[{\beta}-D-xylopyranosyl-(1{\rightarrow}4)-{\alpha}-L-rhamnopyranosyl-(1{\rightarrow}2)]-[5-O-acetyl-{\alpha}-arabinofuranosyl(1{\rightarrow}3)]-[4-O-acetyl-{\beta}-D-fucopyranosyl]-quillaic\;acid-3-O-[{\beta}-D-galactopyranosyl(1{\rightarrow}2)]6-O-methyl\;ester-{\beta}-D-glucuronopyranoside$ and $28-O-[{\beta}-D-xylopyranosyl-(1{\rightarrow}4)-{\alpha}-L-rhamnopyranosyl-(1{\rightarrow}2)]-[5-O-acetyl-{\alpha}-arabinofuranosyl(1{\rightarrow}3)]-[4-O-acetyl-{\beta}-D-fucopyranosyl]-quillaic\;acid\;-3-O-[{\beta}-D-galactopyranosyl(1{\rightarrow}2)]-6-O-n-butyl\;ester-{\beta}-D-glucuronopyranoside$, respectively.

• 한국미생물·생명공학회지
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• 제26권6호
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• pp.529-536
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• 1998

용존산소(D.O.) level은 유기산 및 포도당을 혼합한 배지에서 Azotobacter vinelandii UWD의 생장 및 생분해성 고분자(PHBV) 생성에 큰 영향을 주었다. 용존산소 level이 높은 경우(5% D.O.)는 낮은 경우(1% D.O.)에 비해 세포의 생장속도가 약 2배 증가하였으나 PHBV 생성은 D.O.가 낮은 경우 62.3 wt%로 D.O.가 높은 경우에 비해 약 17배 증가하였다. 그러나 B.O. level은 통기(aeration)에 의한 A. vinefandii UWD의 발효특성 연구에 적합한 기준이 아니었다. 공기공급속도를 고정하고 교반속도만을 변화시키는 통기법으로 산소전달속도를 감소시켰을 때 이 균주는 산소소모속도를 그에 따라 대응 감소시킴으써 겉보기 D.O.를 높게(5%) 유지할 수 있었고 이 때 생장이 느려지고 PHBV 양은 57.3 wt%로 증가하였다. 통기가 세포생장 및 PHBV 생성에 미치는 영향을 일관성 있게 설명할 수 있는 기준은 D.O. level이 아니라 산소전달속도였으며 비생장속도는 산소전달속도에 비례하여 증가하였고 PHBV 생산량은 산소전달속도에 반비례하였다.

• Bulletin of the Korean Chemical Society
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• 제16권7호
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• pp.625-630
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• 1995

α-Linked D-altropyranosidic derivatives were obtained by configurational change at C-3 of α-D-mannopyranosides as the key step in preparation of allyl and methyl α-D-glycopyranosides of 6-deoxy-D-altro-heptose. The manno-altro conversion was effected by sequential reactions of Swern oxidation and stereoselective borohydride reduction. Allyl 4,6-O-benzylidene-2-O-p-methoxybenzyl-α-D-mannopyranoside was transformed to the corresponding altropyranoside via 3-oxo-arabino-hexopyranoside. Allyl 7-O-benzyl-6-deoxy-3,4-O-isopropylidene-α-D-altro-heptopyranoside has been prepared as a glycosyl acceptor to be coupled with β-D-GlcpNAc-(1→3)-α-D-Galp glycosyl donor for the synthesis of an O-antigen repeating unit of Campylobacter jejuni serotypes O:23 and O:36. Stereoselective borohydride reduction also succeeded in yielding methyl 2,4,7-tri-O-benzyl-6-deoxy-α-D-altro-heptopyranoside from the corresponding 3-oxo-α-D-arabino-heptopyranoside. C-6 Homologation was achieved by sequential reactions of cyanide displacement of 6-sulphonates, reduction of the resulting heptopyranosidurononitrile with diisobutylaluminum hydride, hydrolysis of the imine, and further reduction with sodium borohydride.

• 한국광학회지
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• 제19권6호
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• pp.435-438
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• 2008

중수($D_2O$, 산화중수소)는 수소원자(H)보다 중성자 한 개가 더 많은 수소원자 동위원소(D)로 이루어진 물이다. 중수는 자연 상태의 물 가운데 5만분의 1정도 존재하며 경수($H_2O$)와 매우 비슷한 성질을 가지고 있으나 경수보다 11%정도 무겁고, 특이점은 235 K로 228 K인 경수와 약간의 차이를 가진다. 중수는 중성자를 흡수하여 원자로의 중성자 감속재로 쓰이고 최근 중수 농도에 따라 세포에 미치는 독성효과가 다르게 나타나는 현상이 발견 되어 암 치료에 사용하려는 연구가 진행되고 있다. 우리는 테라헤르츠 시간축 분광학을 이용하여 경수와 중수 혼합물의 농도별 굴절률과 흡수율 변화를 거대 분자간 결합에너지 영역을 포함하는 테라헤르츠 영역 ($0{\sim}2.5\;THz$)에서 측정하여 중수의 비율이 높을수록 굴절률은 감소하고 흡수율 또한 감소하는 결과를 얻었다.

• Bulletin of the Korean Chemical Society
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• 제14권2호
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• pp.188-191
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• 1993

The reaction between methyl 2,3-di-O-benzyl-4,6-di-O-mesyl-${\alpha}$-D-glucopyranoside (1b) and potassium superoxide resulted in hydrolysis, and gave methyl 2,3-di-O-benzyl-${\alpha}$-D-glucopyranoside (1) as a sole product. When the reaction was performed with a vicinal dimesylate, methyl 4,6-O-benzylidene-2,3-di-O-mesyl-${\alpha}$-D-altropyranoside (4b), again the hydrolysis product, methyl 4,6-O-benzylidene-${\alpha}$-D-altropyranoside (4) was obtained. However, the reaction of potassium superoxide with another vicinal dimesylate, methyl 4,6-O-benzylidene-2,3-di-O-mesyl-${\alpha}$-D-glucopyranoside (3b), nucleophilic displacement took place to afford methyl 4,6-O-benzylidene-${\alpha}$-D-altropyranoside (4). Apparently different results from two trans vicinal dimesylates, 3b and 4b are explained by the transient formation of epoxides, methyl 2,3-anhydro-4,6-O-benzylidene-${\alpha}$-D-allopyranoside (8) and methyl 2,3-anhydro-4,6-O-benzylidene-${\alpha}$-D-mannopyranoside (9) by $KO_2$. The reaction between the allo epoxide 8 and $KO_2$ gave altro 4. The manno epoxide 9 also afforded altro 4 as the major product. Facile epoxide formation by the reaction of a vicinal dimesylate and superoxide was also observed with 3-O-benzyl-1,2-O-isopropylidene-5,6-di-O-mesyl-${\alpha}$-D-glucofuranose: 5,6-anhydro-3-O-benzyl-1,2-O-isopropylidene-${\beta}$-L-idofuranose was obtained.

• 한국농촌건축학회논문집
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• 제3권2호
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• pp.13-24
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• 2001

Some companies of domestic construction indicate recently that modern life for the aged prefer an advanced technical alliance between O.D.L and I.D.L systems. It means the quality of housing life of the aged has been raised and changed quickly as well as the O.D.L and I.D.L systems since the last year. These preliminary studies suggest that the aged people in the country suffer from insufficient O.D.L and I.D.L systems caused by nation-wide economic poverty compared with the aged people in Seoul. The information from the country has been restricted for several decades therefore some details of the results of the studies are at times difficult to believe and differ depending on the research methods. The purpose of this study is to clarify the quality housing life of the aged, based on the comparative analysis between the O.D.L and I.D.L systems. The quality of housing life of the aged in countryside has been revealed by the clarification of the conditions housing supply, facilities, and therefore housing the cost amount. The conclusions are as follows ; The quickly changing architectural O.D.L elements are presented below in 17 items, while the I.D.L elements are presented in 18 items.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.2089-2094
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• 2003

The flow around a circular cylinder was controlled by attaching O-rings to reduce drag force acting on the cylinder. Four experimental models were tested in this study; one smooth cylinder of diameter D (D=60mm) and three cylinders fitted with O-rings of diameters d=0.0167D, 0.05D and 0.067D with pitches of PPD=1D, 0.5D and 0.25D. The drag force, mean velocity and turbulent intensity profiles in the near wake behind the cylinders were measured for Reynolds numbers based on the cylinder diameter in the range of $Re_D=7.8{\times}10^3{\sim}1.2{\times}10^5$. At $Re_D=1.2{\times}10^5$, the cylinder fitted with O-rings of d=0.0167D in a pitch interval of 0.25D shows the maximum drag reduction of about 5.4%, compared with the smooth cylinder. The drag reduction effect of O-rings of d=0.067D is not so high. For O-ring circulars, as the Reynolds number increases, the peak location of turbulence intensity shifts downstream and the peak magnitude is decreased. Flow field around the cylinders was visualized using a smoke-wire technique to see the flow structure qualitatively. The size of vortices and vortex formation region formed behind the O-ring cylinders are smaller, compared with the smooth cylinder.

• 대한교통학회지
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• 제19권1호
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• pp.77-88
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• 2001

현재까지의 관측교통량기반 수요추정법은 단일차종(singleclass)기반 연구가 대부분을 차지하고 있다. 그러나 현실 교통망에서는 여러 차종이 혼재되어 교통수요나 흐름을 만든다. 즉, 기존의 관측교통량기반 수요추정법은 PCE(Passenger Car Equivalent) 환산을 통한 여러 개의 차종O/D 및 관측교통량을 승용차 단위로 전환하여 하나의 O/D 및 관측교통량으로 만들어 O/D를 추정하고, 최초의 PCE환산이전 차종별 O/D의 고정비율과 관측교통량 고정비율로 곱해 차종별 O/D 및 관측교통량으로 나누어 분석하는 것이 일반적인 방법이었다. 즉, 다차종기반분석법은 각각의 차종별 O/D에 대한 노선선택비율을 각각 계산하고, 그에 따른 목적함수 감소방향인 gradient를 또한 각각 계산하여 차종별 추정력을 극대화하는 것이 그 장점이라고 할 수 있다. 따라서, 본 연구에서는 단일차종기반추정법을 다차종기반추정법으로 확장하여 차종간 혼잡을 고려한 보다 현실적인 수요추정기법을 마련하는 것이 본 연구의 목적이라고 하겠다.