• 약학회지
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• 제40권3호
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• pp.262-272
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• 1996

The constituents of Sanguisorba hakusanensis leaves (Rosaceae), of which the roots have been used as an astringent, hemostatics and antiphlogistics, were studied phytoche mically. From water fraction of the MeOH extract, gallic acid 3-O-${\beta}$-D-(6'-O-galloyl)-glucopyranoside(I), quercetin-3-O-${\beta$-D-galactopyranoside(II), quercetin-3-O-${\alpha}$-L-arabinopyranoside(III) and $2{\alpha},\;3{\beta},\;19{\alpha}$, 23-tetrahydroxyurs-12-en-28-oic acid 28-O-${\beta}$-D-glucopyranoside(IV) were isolated by column chromatographic separation using Amberlite XAD-2, ODS-gel and Sephadex LH-20. The structure of these compounds were elucidated by spectroscopic parameters of $^1H$-NMR, $^{13}C$-NMR, $^1H-^1H$ COSY, $^{13}C-^1H$ COSY, EI-Mass, FAB-Mass, IR, UV and by comparison with authentic samples.

• 약학회지
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• 제40권2호
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• pp.170-176
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• 1996

A chemical examination of the aerial parts of Euphorbia pekinensis $R_{UPRECHT}$. (Euphorbiaceae) has led to the isolation of seven hydrolyzable tannins and ten fl avonoid glycosides. The former ones have been identified as gallic acid, methylgallate, 3-O-galloyl shikimic acid, 1,3,4,6-tetra-O-galloyl-${\beta}-_D$-glucose, 1,2,3,4,6-penta-O-galloyl-${\beta}-_D$-glucose, corilagin, geraniin and the latter ones as isoquercitrin, quercitrin, astragalin, afzelin, prunin, rutin, kaempferol-3-O-rutinoside, quercetin-3-O-(2"-O-galloyl)-${\beta}-_D$-glucoside and quercetin-3-O-(2"-O-galloyl)-${\alpha}-_L$-rhamnoside on the basis of chemical and spectroscopic evidence.

• 대한교통학회지
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• 제31권2호
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• pp.45-59
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• 2013

이 연구는 우리나라에서 현재까지 사용되어 온 (수단O/D기반)화물수요추정법의 문제점 인식을 바탕으로 P/C기반 화물수요추정법과 비교 분석을 수행하였다. 우리나라 화물수단O/D는 화물의 최초기점과 최종종점 간 운송을 수단별 통행으로 나누어 인식하면서 접근트럭통행(Access/Egress Truck Trip)에 대한 정보가 누락되어있다. 이러한 이유로 수단O/D기반 화물수요추정법은 화물의 복합수단운송을 반영하지 못하는 단점이 있다. 이에, 본 연구는 우리나라 컨테이너 화물을 중심으로 P/C표와 복합수단선택모형을 추정하여 P/C기반 화물수요추정법을 제시하고, 기존 사용되어 오던 수단O/D기반 화물수요추정법과 기종점쌍 간 전환량, 수단통행물동량, 링크물동량을 비교하였다. 비교 결과 P/C기반 화물수요추정법은 복합운송을 제대로 모사하지 못하는 기존 수단O/D기반 화물수요추정법의 문제점을 해결할 수 있는 것으로 평가되었다.

• Journal of applied mathematics & informatics
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• 제17권1_2_3호
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• pp.605-614
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• 2005

We show that an Artinian O-sequence $h_0,h_1,{\cdots},h_{d-1},h_d\;=\;h_{d-1},h_{d+l}\;>\;h_d$ of codimension 3 is not level when $h_{d-1}\;=\;h_d\;=\;d + i\;and\;h{d+1}\;=\;d+(i+1)\;for\;i\;=\;1,\;2,\;and\;3$, which is a partial answer to the question in [9]. We also introduce an algorithm for finding noncancelable Betti numbers of minimal free resolutions of all possible Artinian O-sequences based on the theorem of Froberg and Laksov in [2].

• Natural Product Sciences
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• 제20권3호
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• pp.211-215
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• 2014

Opuntia humifusa, also called as Cheonnyuncho, is a cactus widely cultivated in southern regions of Korea. It has been known to have diverse biological activities, but most of the studies were performed with the MeOH extracts or solvent-partitioned fractions. Furthermore, the efforts to identify the responsible compounds for the biological activities are very limited. In this study, we tested the inhibitory effect of extracts and solvent-partitioned fractions of O. humifusa against LPS-induced nitric oxide (NO) production in Raw264.7 cells. The butanol fractions of O. humifusa efficiently inhibited the production of NO in Raw264.7 cells, but it was not due to the reduction of cell viability. Bioassay-guided isolation of butanol fractions of O. humifusa allowed the isolation of three flavonoids isorhamnetin 3-O-${\beta}$-$\small{D}$-galactosyl-4'-O-${\beta}$-$\small{D}$-glucoside (1), isorhamnetin 3,4'-di-O-${\beta}$-$\small{D}$-glucoside (2) and isorhamnetin 3-O-${\beta}$-$\small{D}$-(6-O-${\alpha}$-$\small{L}$-rhamnosyl)glucoside (3), and one lignan syringaresinol O-${\beta}$-$\small{D}$-glucopyranoside (4). Among them, isorhamnetin 3-O-${\beta}$-$\small{D}$-galactosyl-4'-O-${\beta}$-$\small{D}$-glucoside (1) and isorhamnetin 3,4'-di-O-${\beta}$-$\small{D}$-glucoside (2) exhibited the moderate inhibitory effects against LPS-induced NO production. This is the first time to report anti-inflammatory effects of these compounds.

• Korean Journal of Chemical Engineering
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• 제35권11호
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• pp.2185-2190
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• 2018

Methane activation through oxychlorination is in the spotlight due to the relatively mild reaction conditions at atmospheric pressure and in the temperature range of $450-550^{\circ}C$. Although $CeO_2$ is known to exhibit good activity for methane oxychlorination, significant amounts of by-products such as $CO_2$, CO and carbon deposits are produced during the reaction over $CeO_2$. We investigated the effect of iron in $FeO_x/CeO_2$ catalysts on methane oxychlorination. $FeO_x/CeO_2$ with 3 wt% iron shows the maximum yield at $510^{\circ}C$ with 23% conversion of methane and 65% selectivity of chloromethane. XRD and $H_2$ TPR results indicate that iron-cerium solid solution was formed, resulting in the production of more easily reduced cerium oxide and the suppression of catalysts sintering during the reaction. Furthermore, the selectivity of by-products decreased more significantly over $FeO_x/CeO_2$ than cerium oxide, which can be attributed to the facilitation of HCl oxidation arising from the enhanced reducibility of the former sample.

• 전기전자학회논문지
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• 제27권4호
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• pp.399-404
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• 2023

본 논문에서는 3D NAND Flash memory의 O/N/O(Oxide/Nitride/Oxide) 구조와 blocking oxide를 ferroelectric material로 대체한 O/N/F(Oxide/Nitride/Ferroelectric) 구조의 current path를 분석했다. O/N/O 구조는 V_read가 인가되면 neighboring cell의 E-field로 인해 current path가 channel 후면에 형성된다. 반면 O/N/F 구조는 ferroelectric material의 polarization으로 인해 electron이 channel 전면으로 이동하여 current path가 전면에 형성된다. 또한 channel thickness와 channel length에 따른 소자 특성을 분석했다. 분석 결과 O/N/F 구조의 전면 electron current density 증가는 O/N/O 구조보다 2.8배 더 높았고 O/N/F 구조의 전면 electron current density 비율이 17.7% 높았다. 따라서 O/N/O 구조보다 O/N/F 구조에서 전면 current path가 더 효과적으로 형성된다.

• BMB Reports
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• 제35권4호
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• pp.403-408
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• 2002

A hypothetical 21.0 kDa protein (ORF O197) from Escherichia coli K-12 was cloned, purified, and characterized. The protein sequence of ORF O197(termed EcO197) shares a 33.5% identity with that of a novel NTPase from Methanococcus jannaschii. The EcO197 protein was purified using Ni-NTA affinity chromatography, protease digestion, and gel filtration column. It hydrolyzed nucleoside triphosphates with an O6 atom-containing purine base to nucleoside monophosphate and pyrophosphate. The EcO197 protein had a strong preference for deoxyinosine triphosphate (dITP) and xanthosine triphosphate (XTP), while it had little activity in the standard nucleoside triphosphates (dATP, dCTP, dGTP, and dTTP). These aberrant nucleotides can be produced by oxidative deamination from purine nucleotides in cells; they are potentially mutagenic. The mutation protection mechanisms are caused by the incorporation into DNA of unwelcome nucleotides that are formed spontaneously. The EcO197 protein may function to eliminate specifically damaged purine nucleotide that contains the 6-keto group. This protein appears to be the first eubacterial dITP-and XTP-hydrolyzing enzyme that has been identified.

• 한국ITS학회 논문지
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• 제7권5호
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• pp.180-183
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• 2008

본 논문은 교통망에서 관측 링크 교통량, 미관측 링크의 이용자평형 정보를 이용하여 O-D행렬을 수학적으로 생성하는 모형을 제시하고 있다. 교통량이 관측되지 않은 링크로부터 이용자 평형 상태에서 추출 가능한 정보를 바탕으로 일련의 논리적 연산을 거쳐 실제교통량에 근접하는 서브알고리듬을 유추하여 O-D행렬 추정의 정확도와 연산의 일관성을 제고하였다. 이를 위해 이용자평형상태에서 새로운 정리(Theorem)와 보조정리(Lemma)를 유도하여 적용하였다. 모형의 시험은 3개의 초기 O-D 행렬과 3개의 미관측 링크 교통량 시나리오를 각각의 모형에 적용하여 그 결과를 비교하였다. 적용 결과 본 논문에서 제시된 모형은 기존의 이용자균형 접근방식의 모형emf에 비해 추정된 O-D값의 실제 값과의 차이(O-D Trip RMSE)가 현저히 감소되는 것을 확인하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.164-164
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• 2010

The impurity doped ZnO has been extensively studied because of its optoelectric properties. GIZO (Ga-In-Zn-O) amorphous oxide semiconductors has been widely used as transparent flexible semiconductor material. Recently, various amorphous transparent semiconductors such as IZO (In-Zn-O), GIZO, and HIZO (Hf-In-Zn-O) were developed. In this work, we examined the local structures of IZO, GIZO, and HIZO. The local coordination structure was investigated by the extended X-ray absorption fine structure. The IZO, GIZO and HIZO thin films ware deposited on the glass substrate with thickness of 400nm by the radio frequency sputtering method. The targets were prepared by the mixture of $In_2O_3$, ZnO and $HfO_2$ powders. The percent ratio of In:Zn in IZO, Ga:In:Zn in GIZO and Hf:In:Zn in HIZO was 45:55, 33:33:33 and 10:35:55, respectively. In this work, we found that IZO, GIZO and HIZO are all amorphous and have a similar local structure. Also, we obtained the bond distances of $d_{Ga-O}=1.85\;{\AA}$, $d_{Zn-O}=1.98\;{\AA}$, $d_{Hf-O}=2.08\;{\AA}$, $d_{In-O}=2.13\;{\AA}$.