• Natural Product Sciences
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• 제12권3호
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• pp.122-124
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• 2006

Three flavonoid glycosides, $kaempferol-3-O-{\alpha}-L-rhamnopyranosyl-(1\;{\rightarrow}\;6)-{\beta}$-D-glucopyranoside$ or kaempferol-3-O-rutinoside (1), $isorhamnetic-3-O-{\alpha}-L-rhamnopyranosyl-(16)-{\beta}-D-glucopyranoside$ or isorhamnetin-3-O-rutinoside (2), and $quercetin-3-O-{\beta}-D-glucopyranosyl-(1 ${\rightarrow}\;2)-{\beta}-L-arabinopyranoside$ 3, the latter one being a new compound, were isolated from the methanolic extract of the aerial parts of Carrichtera annua. Mass spectrometry and 1D and 2D NMR spectroscopy allowed establishing the structure of these compounds.

• 대한화학회지
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• 제35권4호
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• pp.316-323
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• 1991

초전도체 이트륨계 계열 중 임계온도 95 K인 YBa$_2Cu_3O_{7-x}$ 초전도계(123 system)와 80 K 인 YBa$_2Cu_4O_8$ 초전도계(124 system)의 차이점을 확장 Huckel 분자궤도론(EHT)으로 계산하였다. 123계와 124계의 layer와 chain에 대한 하전 Cu-O cluster 모델을 각각 계산한 다음 원자가 전자분포(Valence Electron Population, VEP), 환산 겹침분포(Reduced Overlap Population, ROP) 그리고 알짜 전하(net charge)를 비교하였다. 그 결과 123 및 124계의 layer에 있어서 구리원자의 원자가 전자는 d$_{x^2-y^2}$ 오비탈 보다는 d$_{z^2}$ 오비탈에 더 많이 분포되어 있음을 알 수 있었고, chain에 있어서 구리원자의 원자가 전자는 d$_{z^2}$ 오비탈보다는 d$_{y^2-z^2}$ 오비탈에서 더 많이 분포되어 있음을 알 수 있었다. 123계에 있어서 ROP는 Y 방향의 Cu(1)-O(2)보다 X 방향의 Cu(1)-O(1)가 더 크다는 것을 알 수 있었고, 124계에 있어서 layer의 ROP는 X 방향의 Cu(1)-O(1)보다 Y 방향의 Cu(1)-O(2)가 더 크다는 것을 알 수 있었다. 그러나 123 및 124 계에 있어서 chain의 ROP는 Y 방향의 Cu(2)-O(3)보다 Z 방향의 Cu(2)-O(4)가 더 크다는 것을 알 수 있었다. 123계의 layer에 존재하는 구리의 알짜 전하는 chain에 존재하는 구리의 알짜 전하보다 더 큰 반면 124계의 chain에 존재하는 구리의 알짜 전하는 layer에 존재하는 구리의 알짜 전하보다 더 크다는 것을 알 수 있었다.)-O(2)가 더 크다는 것을 알 수 있었다. 그러나 123 및 124 계에 있어서 chain의 ROP는 Y 방향의 Cu(2)-O(3)보다 Z 방향의 Cu(2)-O(4)가 더 크다는 것을 알 수 있었다. 123계의 layer에 존재하는 구리의 알짜 전하는 chain에 존재하는 구리의 알짜 전하보다 더 큰 반면 124계의 chain에 존재하는 구리의 알짜 전하는 layer에 존재하는 구리의 알짜 전하보다 더 크다는 것을 알 수 있었다.

• Natural Product Sciences
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• 제18권4호
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• pp.273-278
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• 2012

Further phytochemical investigation on the whole plant of Thyrsanthera suborbicularis, collected in Cambodia, led to kaempferol (1), vitexin (2), apigenin-7-O-neohesperidoside (3), chrysoeriol-7-O-${\beta}$-D-glucopyranoside (4), isorhamnetin 3-O-rutinoside (5), kaempferol-3-O-[${\alpha}$-L-rhamnopyranosyl-(13)-${\alpha}$-L-rhamnopyranosyl-(16)-${\beta}$-D-galactopyranoside (6), kaempferol-3-O-${\alpha}$-L-rhamnopyranosyl(12)-O-[${\alpha}$-L-rhamnopyranosyl (16)]-${\beta}$-D-glucopyranoside (7), kaempferol-3-O-[6"-O-(E)-p-coumaroyl]-${\beta}$-D-glucopyranoside (8), kaempferol-3-O-[6"-O-(E)-p-coumaroyl]-${\beta}$-D-galactopyranoside (9), and amentoflavone (10). All the structures were confirmed by the interpretation of NMR (1D and 2D) and MS data, and comparison with the published values. Of the isolated compounds 1 - 10, compounds 8 and 10 displayed the inhibitory activity against NO production in LPS-induced Raw 264.7 cells with $IC_{50}$ values, 3.56 and $15.73{\mu}M$, respectively.

• Bulletin of the Korean Chemical Society
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• 제28권2호
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• pp.257-262
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• 2007

The efficient synthesis of a tetrasaccharide, the suitably protected form of the repeat unit, →2)-α-D-Manp-(1→2)-β-D-Manp-(1→3)-α-D-GlcpNAc-(1→6)-α-D-Manp-(1→, of the O-antigen polysaccharide of the lipopolysaccharide from E. coli O77 has been accomplished. Glycosylation reactions for the coupling of four monosaccharide building blocks of the tetrasaccharide were carried out employing the CB glycoside method, the mannosyl 4-pentenoate/PhSeOTf method, and the glycosyl trichloroacetimidate method with complete stereoselectivities in excellent yields.

• Applied Biological Chemistry
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• 제43권2호
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• pp.136-140
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• 2000

방울비짜루의 MeOH 추출물 및 수포화 BuOH추출물로부터 항균활성을 확인하고 그 원인물질을 구명하던 중 두 종의 steroid saponin을 분리하였다. 이들의 구조확인을 위해 $^1H,\;^{13}C$ NMR 및 2D NMR 등 분광학적 방법을 사용하였으며 최종 이들의 구조가 25S-spirostane계의 steroid saponin인$3-O-[{\beta}-D-glucopyranosyl-(1{\rightarrow}2)-{\beta}-D-glucopyranosyl]-(25S)-spirostan-3{\beta}-ol$ 및 $3-O-{{\beta}-D-glucopyranosyl-(1{\rightarrow}2)-[{\beta}-D-xylopyranosyl-(1{\rightarrow}4)]-{\beta}-D-glucopyranosyl}-(25S)-spirostan-3{\beta}-ol$인 것으로 동정되었다. 이 두 화합물은 방울비짜루로부터는 처음으로 분리되었다. 이들 saponin의 항균활성 및 항균 스펙트럼을 검사하기 위하여 20개 균주에 대한 MIC를 실시하였다. 이들은 그중 10개 균주에 대해 $100\;{\mu}g/ml$의 농도에서 세균의 성장을 저지하는 항균력이 있었으며 광범위한 항균 스펙트럼을 나타내었다.

• 한국세라믹학회지
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• 제40권6호
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• pp.547-552
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• 2003

RF 마그네트론 스퍼터링법을 이용하여 유리기판위에 인가전력 100 W, 1.33Pa, Ar/O2=50 : 50, 20$0^{\circ}C$ 그리고 타겟과 기판사이의 거리 4 cm의 조건으로 ZnO 압전 박막을 성장시켰다. 증착된 박막의 결정성, 표면형상, 화학적 결합비와 전기적 특성을 XRD, SEM, AFM, RBS와 electrometer를 이용하여 측정 분석하였다 제조된 박막은 우수한 c축 우선 배향성을 보였고 또한 화학 양론적인 결합비를 나타내었다. 전극 구조가 single 및 double IDT를 갖는 ZnO/1DT/glass SAW 필터를 제작하여 특성을 분석한 결과, 전파속도는 각각 2,589 m/sec, 2,533 m/sec이었고, 삽입손실은 -11 dB과 -21 dB 값을 나타내어 박막형 SAW 필터로 응용이 기대된다.

• Bulletin of the Korean Chemical Society
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• 제18권9호
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• pp.961-965
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• 1997

1H NMR spectra of 3,3-dimethylpiperidine (1) at -70 to 30 ℃ exhibit gradual change from slow to rapid exchange between two alternate chair forms. The exchange rate constant was determined as a function of temperature by simulating the line shape of the signal from the two methyl groups using the modified Bloch equations. The resulting free energy of activation is ΔG* = 44.4±1.9 kJ mol-1 at 298 K. The 1H NMR spectrum of a D2O or dimethylsulfoxide-d6 (DMSO-d6) solution containing 1 and [SiW11CoⅡO39]6- exhibits separate signals for the free ligand and the complex, indicating that the ligand exchange is slow on the NMR time scale. In D2O the piperidine ring is frozen as a chair form even at room temperature with the cobalt ion bonded to the axial position of the nitrogen atom. When DMSO-d6 is added to the D2O solution, the NMR spectral change suggests that a rapid exchange occurs between the chair form and another conformer. It is proposed that the conformation of ^b1^b coordinated to [SiW11CoⅡO39]6- in DMSO-d6 is close to a twist form.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2004년도 SMICS 2004 International Symposium on Maritime and Communication Sciences
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• pp.6-8
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• 2004

The NdBaCuO superconductor samples were zone-melted in low oxygen partial pressure (1 % $O_2$＋99%Ar). The zone-melting temperature was decreased about 12$0^{\circ}C$ from 1, 06$0^{\circ}C$, the zone-melting temperature in air. Thus the loss of liquid phase (BaCu $O_2$and CuO) was reduced during the zone-melting process. The content of non-superconducting phase Nd422 in zone-melted NdBaCuO samples was clearly decreased and, therefore, the substitution of Nd for Ba was occurred. The superconductivity of zone-melted N $d_{1＋x}$B $a_{2－x}$C $u_3$ $O_{y}$prepared under low oxygen partial pressure was distinctively improved.d.d.d.

• Transactions on Electrical and Electronic Materials
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• 제3권2호
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• pp.24-27
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• 2002

The NdBaCuO superconductor samples were zone-melted in low oxygen partial pressure (1%O$_2$+99%Ar). The zone-melting temperature was decreased about 12$0^{\circ}C$ film 1,06$0^{\circ}C$, the zone-melting temperature in air. Thus the loss of liquid phase (BaCuO$_2$ and CuO) was reduced during: the zone-melting process. The content of non-superconducting phase Nd422 in zone-melted NdBaCuO samples was clearly decreased and, therefore, the substitution of Nd for Ba was occurred. The superconductivity of zone-melted Nd$_{1+x}$Ba$_{2-x}$Cu$_3$O$_{y}$ prepared under low oxygen partial pressure was distinctively improved.d.d.d.

• 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 $d_{Ga-O}=1.85\;{\AA}$, $d_{Zn-O}=1.98\;{\AA}$, $d_{Hf-O}=2.08\;{\AA}$, $d_{In-O}=2.13\;{\AA}$.