• 제목/요약/키워드: O-D analysis

검색결과 1,898건 처리시간 0.03초

A New Flavonol Glycoside from Tristemma hirtum (Melastomataceae)

  • Kenfack, Joseph Nandjou;Ponou, Beaudelaire Kemvoufo;Kuhlborn, Jonas;Teponno, Remy Bertrand;Nono, Raymond Ngansop;Fouedjou, Romuald Tematio;Opatz, Till;Park, Hee Juhn;Tapondjou, Leon Azefack
    • Natural Product Sciences
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    • 제24권3호
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    • pp.213-218
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    • 2018
  • Chemical investigation of the plant Tristemma hirtum P. Beauv (Melastomataceae) resulted to the isolation of a new flavonol glycoside named quercetin-7-O-${\alpha}$-D-arabinofuranoside (1), together with nine known compounds including 3'-hexadecanoyl-2'-(9aZ)-tetradecanoyl-glycerol 1'-O-[${\beta}$-D-galactopyranosyl-(1'' ${\rightarrow}$ 6'')-${\alpha}$-D-galactopyranoside] (2), arjunolic acid (3), ${\beta}$-sitosterol-3-O-${\beta}$-D-glucopyranoside (4), terminolic acid (5), quercetin (6), asiatic acid (7), maslinic acid (8), $1{\beta}$-O-galloylpedunculagin (9) and 6-hydroxyapigenin 7-O-${\beta}$-D-glucopyranoside (10) from the methanol extract using normal and reversed phase column chromatography. The structures of these compounds were determined by comprehensive interpretation of their spectral data mainly including 1D- 2D-NMR ($^1H-^1H$ COSY, HSQC, and HMBC) spectroscopic and ESI-TOF-MS mass spectrometric analysis.

디젤기관에서 경유/부탄올 혼합연료의 기관성능 및 연소특성 해석 (Analysis of performance and combustion characteristics of D.O./butanol blended fuels in a diesel engine)

  • 김상암;왕우경
    • 수산해양기술연구
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    • 제55권4호
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    • pp.411-418
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    • 2019
  • In this study, to investigate the effect of physical and chemical properties of butanol on the engine performance and combustion characteristics, the coefficient of variations of IMEP (indicated mean effective pressure) and fuel conversion efficiency were obtained by measuring the combustion pressure and the fuel consumption quantity according to the engine load and the mixing ratio of diesel oil and butanol. In addition, the combustion pressure was analyzed to obtain the pressure increasing rate and heat release rate, and then the combustion temperature was calculated using a single zone combustion model. The experimental and analysis results of butanol blending oil were compared with the those of diesel oil under the similar operation conditions to determine the performance of the engine and combustion characteristics. As a result, the combustion stabilities of D.O. and butanol blending oil were good in this experimental range, and the indicated fuel conversion efficiency of butanol blending oil was slightly higher at low load but that of D.O. was higher above medium load. The premixed combustion period of D.O. was almost constant regardless of the load. As the load was lower and the butanol blending ratio was higher, the premixed combustion period of butanol blending oil was longer and the premixed combustion period was almost constant at high load regardless of butanol blending ratio. The average heat release rate was higher with increasing loads; especially as butanol blending ratio was increased at high load, the average heat release rate of butanol blending oil was higher than that of D.O. In addition, the calculated maximum. combustion temperature of butanol blending oil was higher than that of D.O. at all loads.

3D NAND Flash Memory에서 Tapering된 O/N/O 및 O/N/F 구조의 Threshold Voltage 변화 분석 (The Analysis of Threshold Voltage Shift for Tapered O/N/O and O/N/F Structures in 3D NAND Flash Memory)

  • 이지환;이재우;강명곤
    • 전기전자학회논문지
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    • 제28권1호
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    • pp.110-115
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    • 2024
  • 본 논문은 3D NAND Flash memory에서 tapering된 O/N/O(Oxide/Nitride/Oxide) 구조와 blocking oxide를 ferroelectric material로 대체한 O/N/F(Oxide/Nitride/Ferroelectric) 구조의 Vth(Threshold Voltage) 변화량을 분석했다. Tapering 각도가 0°일 때 O/N/F 구조는 O/N/O 구조보다 저항이 작고 WL(Word-Line) 상부와 WL 하부의 Vth 변화량이 감소한다. Tapering된 3D NAND Flash memory는 WL 상부에서 WL 하부로 내려갈수록 channel 면적이 감소하며 channel 저항이 증가한다. 따라서 tapering 각도가 증가할수록 WL 상부의 Vth가 감소하고 WL 하부의 Vth는 증가한다. Tapering된 O/N/F 구조는 channel 반지름 길이와 비례하는 Vfe로 인해 WL 상부의 Vth는 O/N/O 구조보다 더 감소한다. 또한 O/N/F 구조의 WL 하부는 O/N/O 구조보다 Vth가 증가하기 때문에 tapering 각도에 따른 Vth 변화량이 O/N/O 구조보다 더 증가한다.

A Novel 3D Polypseudo-rotaxane Metal-organic Framework Based on a Flexible Bis-pyridyl-bis-amide Ligand

  • Wang, Xiu-Li;Han, Na;Lin, Hong-Yan;Xu, Chuang;Luan, Jian;Liu, Guo-Cheng
    • Bulletin of the Korean Chemical Society
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    • 제33권11호
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    • pp.3793-3796
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    • 2012
  • A novel 3D compound $\{[Cu(L)(H_2O)_4][Cu_2(SIP)_2(L)_2]\}{\cdot}2H_2O$ (1) (L = N,N-bis(4-pyridinecarboxamide)-1,4-butane, SIP = 5-sulfoisophthalate) is hydrothermally synthesized. X-ray diffraction analysis reveals that compound 1 is composed of 2D anionic $[Cu_2(SIP)_2(L)_2]_n{^{2n-}}$ double-layers and discrete 1D cationic $[CuL(H_2O)_4]_n{^{2n+}}$ polymeric chains, which represents a rare 3D polypseudo-rotaxane MOF from intercalation of 1D and 2D framework. In addition, the luminescent property and electrochemical behavior of compound 1 have been investigated.

Construction of a 2D Co(II) Coordination Polymer with (4,4)-Connected Topology: Synthesis, Crystal Structure, and Surface Photo-electric Property

  • Li, Jia-Ming
    • Bulletin of the Korean Chemical Society
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    • 제35권4호
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    • pp.1177-1181
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    • 2014
  • A 2D grid-like (4, 4)-connected topology coordination polymer, $[Co(BTA)_2(H_2O)_2]_n$ (1), where HBTA = 2-(1H-benzotriazol-1-yl)acetic acid, has been synthesized by hydrothermal method and characterized by single crystal X-ray diffraction, IR spectroscopy, elemental analysis and surface photovoltage spectroscopy (SPS). X-ray diffraction analyses indicated that 1 displays octahedral metal centers with secondary building units (SBUs) [$Co(BTA)_2(H_2O)_2$] bridged by the $BTA^-$ ligands. In the crystal, the 2D supramolecular architecture is further supported by $O-H{\cdots}O$, $O-H{\cdots}N$, $C-H{\cdots}O$ hydrogen bonds and ${\pi}{\cdots}{\pi}$ stacking interactions. The SPS of polymer 1 indicates that there are positive response bands in the range of 300-600 nm showing photo-electric conversion properties. There are good relationships between SPS and UV-Vis spectra.

천연복합소재 LS-RUG-com의 기능성원료 표준화를 위한 산딸기 미숙과, 치자 및 유백피 지표성분의 분석법 검증 (Validation of Analytical Methods for Unriped Rubus crataegifolius, Gardenia jasminoides and Ulmus macrocarpa Marker Compounds for Standardization of Natural Complex LS-RUG-com Preparation as Functional Ingredient)

  • 이영익;표수진;이희진;윤혜정;손호용;조진숙
    • 생명과학회지
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    • 제34권1호
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    • pp.59-67
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    • 2024
  • 산딸기, 치자, 유백피의 혼합물인 복합 천연물 LS-RUG-com이 위염, 위궤양, 식도성 역류염 및 Helicobacter를 억제함을 확인한 바, LS-RUG-com을 건강기능식품 개별인정형 소재로 개발하고자 하였다. 본 연구에서는 소재 개발을 위한 LS-RUG-com 분석방법을 확립하고자 하였으며, 산딸기, 치자 및 유백피의 지표물질을 HPLC/UV system을 이용하여 분석방법을 최적화하였다. 본 연구에서는 분석법 validation을 입증하기 위하여 특이성(specificity), 정확성(accuracy), 정밀성(precision), 검출한계 및 정량한계(detection & quantitation limit) 및 직선성(linearity)을 평가하였으며, 그 결과 본 연구의 HPLC/UV 동시 분석법이 산딸기, 치자 분석에 적합하며, 신뢰성이 있음을 증명하였다. 또한 유백피의 HPLC/UV 단독 분석법이 적합하며 신뢰성이 있음을 증명하였다.

Anti-oxidative and Antibacterial Constituents from Sedum hybridum

  • Gendaram, Odontuya;Choi, Yoen-Hee;Kim, Young-Sup;Ryu, Shi-Yong
    • Natural Product Sciences
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    • 제17권4호
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    • pp.279-284
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    • 2011
  • Phytochemical studies on the whole extract of Sedum hybridum L., a Mongolian medicinal plant, has been undertaken to isolate active principles responsible for its anti-oxidative and antibacterial activities. Eighteen known compounds, i.e. (1) quercetin, (2) kaempferol, (3) herbacetin-8-O-${\beta}$-D-xylopyranoside, (4) myricetin, (5) gossypetin-8-O-${\beta}$-D-xylopyranoside, (6) gallic acid, (7) 2,4,6-tri-O-galloyl-D-glucopyranose, (8) 6-O-galloylarbutin, (9) myricetin-3-O-${\alpha}$-L-arabinofuranoside, (10) quercetin-3-O-${\alpha}$-L-arabinofuranoside, (11) caffeic acid, (12) ethylgallate, (13) (-) epigallocatechin-3-O-gallate, (14) palmitic acid, (15) stearic acid, (16) stearic acid ethyl ether, (17) ${\beta}$-sitosterol and (18) ${\beta}$-sitosteryl-O-${\beta}$-D-glucopyranose have been isolated and their molecular structures identified by spectroscopic analysis. Thirteen substances including seven flavonol components (1, 2, 3, 4, 5, 9 and 10), five gallic acid derivatives (6, 7, 8, 12 and 13) and caffeic acid (11) exhibited significant, dose-dependent, DPPH radical scavenging activity. Galloyl esters 12 and 13 were revealed to be main active principles for the antibacterial property of the extract of Sedum hybridum L.

ICBD 법에 의한 $ Y_2O_3$박막특성에 관한 연구 (Properties of $ Y_2O_3$ Thin Films Prepared by ICBD Method)

  • 전정식;문종;이상인;심태언;황정남
    • 한국진공학회지
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    • 제5권3호
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    • pp.245-250
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    • 1996
  • $Y_2O_3$ thin film on si(100) was successfully grown by ionized cluster beam(ICBD) technique at substrate temperature of around $500^{\circ}C$ and pressure of ~$10^{-5}$Torr.To prevent the oxidation of Si substrae, a very thin yttrium layer was deposited on Si before reactive depositing of oxygen and yttrium source. In asdeposited stage, b.c.c and h.c.p strucutres of $Y_2O_3$ were observed from S-ary analysis. From the observation of spots and ring patterns in selected area diffractin(SAD) patterns. crystallane formation and growth could be proceeded during the deposition. $Y_2O_3$/mixed layer/$SiO_2=170\AA/50\AA/10\AA$ structure were verified by high resolution transmition electron imcroscopy(HRTEM) image, and the formation of amorphous layer of SiO2 was discussed . Electricla charateristics of the film were also investigated . In as-deposited Pt/$Y_2O_3$/Si sturcuture, leakage current was less than $10^{-6}$A/$\textrm{cm}^2$ at 7MV/cm strength.

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Photocatalytic Hydrogen Production in Water-Methanol Mixture over Iron-doped CaTiO3

  • Jang, J. S.;Borse, P. H.;Lee, J. S.;Lim, K. T.;Jung, O. S.;Jeong, E. D.;Bae, J. S.;Kim, H. G.
    • Bulletin of the Korean Chemical Society
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    • 제32권1호
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    • pp.95-99
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    • 2011
  • $CaTi_{1-x}Fe_xO_3(0{\leq}x{\leq}0.4)$ solid solution photocatalysts were synthesized by iron doping during the conventional solid state reaction at $1100^{\circ}C$ for 5 h and characterized by ultraviolet-visible (UV-vis) absorption spectroscopy, X-ray diffraction, morphological analysis. We found that $CaTi_{1-x}Fe_xO_3$ samples not only absorb UV but also the visible light photons. This is because the Fe substitution at Ti-site in $CaTi_{1-x}Fe_xO_3$ lattice induces the band transition from Fe3d to the Fe3d + Ti3d hybrid orbital. The photocatalytic activity of Fe doped $CaTiO_3$ samples for hydrogen production under UV light irradiation decreased with the increase in the Fe concentration. There exists an optimized concentration of iron in $CaTiO_3$, which yields a maximum photocatalytic activity under visible light ($\lambda\geq420nm$) photons.

Tragacanth gum 의 신다당류(新多糖類) C 의 화학구조(化學構造) - Tragacanth gum의 신다당류(新多糖類)에 관(關)한 연구(硏究) 제2보(第二報) - (Studies on the Chemical Structure of the New Polysaccharide C - (The New Polysaccharides of Gum Tragacanth. II) -)

  • 이성환
    • Applied Biological Chemistry
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    • 제3권
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    • pp.25-48
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    • 1962
  • tragacanth gum의 화학구조(化學構造)를 구명(究明)하기 위(爲)하여 미국(美國) 약전(藥典)의 tragacanth gum 분말(粉末)을 가지고 다음의 실험(實驗)을 통(通)하여 이의 성분(成分)의 하나인 polysaccharide C를 분리(分離)하여 이의 화학구조(化學構造)를 밝혔다. (1) tragacanth gum을 85% 주정(酒精)으로 처리(處理)해서 중성다당류(中性多糖類)로 polysaccharide C를 분리(分離)하였으며 구성당(構成糖)으로 L-rhamnose, D-xylose, L-arabinose 및 D-galactose를 paper chromatography와 Cellulose column chromatography로 분리(分離), 동정(同定)하였다. 이의 molar ratio는 2:1:17:9이며 비선광도(比旋光度)는 $[{\alpha}]^{30}_D-72.2이다. (2) 구성당(構成糖)의 결합위치(結合位置)를 구명(究明)하기 위(爲)해 Hawarth 법(法)과 Purdietldir(試藥)을 가지고 methyl화(化)시켜 methyl화(化) polysaccharide C를 얻었으며 비선광도(比旋光度) $[{\alpha}]^{22}_D-102를 보였다. 이것을 가수분해(加水分解)시켜 paper chromatography와 column chromatography를 통(通)해 methyl화단당(化單糖)으로 1,3,5-tri-O-methyl-L-arabofuranose, 3,4-di-O-methyl-L-rhamnose, 2,3-di-O-methyl-D-xylose, 2,3,4-tri-O-methyl-D-galactopyranose, 2,4-di-O-methyl-L-arabopyronose, 2,4-di-O-methyl-D-galactose, 2-O-methyl-L-arabinose 및 L-arabinose를 분리(分離), 동정(同定)하였다. (3) 산(酸)의 각종농도(各種濃度)에 따른 부분적(部分的) 가수분해(加水分解)를 시켜 polysaccharide C의 end group, 측지(側枝) 또는 주쇄(主鎖)를 이루는 구성당(構成糖)을 밝히기 위(爲)하여 0.05 N-HCl로 제1차(第一次) 가수분해(加水分解). 0.1N-HCl로 제2차(第二次) 가수분해(加水分解), 0.3N-HCl로 제3차(第三次) 가수분해(加水分解)를 하여 가수분해물(加水分解物)과 비가수분해물(非加水分解物)에서 각각(各各) 다음과 같은 구성단당(構成單糖)을 검출(檢出)하고 이들의 molar ratio를 측정(測定)하였다. 제1차(第一次) 가수분해물(加水分解物)(A)에서 L-arbinose, 비가수분해물(非加水分解物)(A')에서 L-rhamnose, D-xylose, L-arabinose 및 D-galactose; 제2차(第二次) 가수분해물(加水分解物)(B)에서 L-arabinose와 D-galactose, 비가수분해물(非加水分解物)(B')에서 L-rhamnose, D-xylose, L-arabinose, 및 D-galactose; 제3차(第三次) 가수분해물(加水分解物)(C)에서 L-rhamnose, D-xylose, L-arabinose 및 D-galactose, 비가수분해물(非加水分解物)(C')에서 D-xylose와 D-galactose를 검출(檢出)하였다. (4) 구성당(構成糖)의 형태(形態)와 구조(構造)를 밝히기 위(爲)해 polysaccharide C에 대한 periodate산화(酸化) 실험(實驗)을 하여 $C_5H_8O_4$당(當) periodate의 소비(消費)와 formic acid의 생성량(生成量)을 측정(測定)하였는데 periodate의 소비량(消費量)은 1.23 mole, formic acid의 생성량(生成量)은 0.78 mole이다.

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