• 대한화학회지
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• 제39권10호
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• pp.799-805
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• 1995

96개의 allyl기를 가진 나무가지꼴 실란 거대분자를 alkenylation 과 hydrosilylation의 반복된 과정을 경유하여 매우 높은 수율로 합성하였다. 이 두 과정을 통해서 나무가지꼴 거대분자는 크로마토그래피법을 이용한 정제법(silica hel, chloroform)에서 순수한 물질을 얻어졌음이 $/_1/H,\;/_13/CNMR$과 원소분석 등에 의해 확인되었다.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1998년도 PROCEEDINGS OF THE 14TH KACG TECHNICAL MEETING AND THE 5TH KOREA-JAPAN EMGS (ELECTRONIC MATERIALS GROWTH SYMPOSIUM)
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• pp.161-164
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• 1998

Erbium doped garnet crystals were grown by Czochralski method. Relationshipes between crystal quality and crystal growth factors such as pulling rate, rotation rate and concentration of active ions and sensitizers were investigated. Optimum pulling and rotation rate for high quality Er:YAG crystal were 1 mm/hr and 20 rpm and for Er,Cr:YSGG crystal 2-4 mm/hr and 10 rpm respectively. The size of the crystals grown was up to 20-30 mm in diameters and 95-135 mm in length. Er:YAG crystal grown under the nitrogen atmosphere was pink and transparent and Er,Cr:YSGG under the 98% {{{{ { N}_{ 2} }}}} and 2% {{{{ { O}_{2 } }}}} was dark green and transparent. Under the polarizing microscopic observations with crossed polar, striations and {211} core facets were detected. Spectroscopic properties for Er,Cr:YSGG laser rods with <111> axis, 80 mm in length and 6.3 mm in diameter for medical laser applications of 2.79 ${\mu}$m wavelength were manufactured and then laser oscillation was achieved.

• 한국세라믹학회지
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• 제54권1호
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• pp.28-32
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• 2017

The degradation of methyl blue (MB) catalyzed by platinum (Pt)-graphene/$TiO_2$ in dark ambiance was studied. Pt-graphene/$TiO_2$ composites were prepared by simple hydrothermal method. Characterizations of composites were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), specific surface area (BET) analysis, and energy dispersive X-ray (EDX) analysis. UV-spectroscopic analysis of the dyes was performed by measuring the change in absorbance. The degradation of the organic dyes was calculated based on the decrease in concentration of the dyes with respect to regular time intervals. Rate coefficients for the catalytic process were successfully established and reusability tests were performed to test the stability of the used catalysts.

• Journal of Electrochemical Science and Technology
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• 제11권2호
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• pp.165-171
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• 2020

The electrochemical preparation and spectroscopic characterisation of iridium-antimony (Ir-Sb) species is important owing to their potential applications as nanostructure materials. Nanostructures, i.e. nanoflower and nanodisk, of Ir-Sb were electrodeposited on conductive substrates using a practical electrochemical method based on the simultaneous underpotential deposition (UPD) of Ir and Sb from the IrCl₃ and Sb₂O₃ at a constant potential. Electrochemical UPD mechanism of Ir-Sb was studied using cyclic voltammetry and potential-controlled electrochemical deposition techniques. Herein, X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron and Raman spectroscopy were used to determine the morphological and structural properties of the electrochemically-synthesised Ir-Sb nanostructures.

• 생약학회지
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• 제33권4호통권131호
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• pp.277-284
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• 2002

For the quality control of Kalopanacis Cortex, saponin compound, kalopanax-saponin B was isolated from the MeOH extract of Kalopanacis Cortex, and identified by the spectroscopic evidences. A quantitative analysis of kalopanaxsapo-nits B using HPLC method showed that the average contents was $1.010{\pm}0.212%$, respectively, in 22 samples collected through-out the regions of Korea.

• Bulletin of the Korean Chemical Society
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• 제26권3호
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• pp.447-450
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• 2005

The crude methanol extract of the fruits of Amomum tsao-ko (Zingiberaceae) showed cytotoxic activity. Bioactivity-guided separation led to the isolation of a diarylheptanoid, tsaokoarylone [7-(4-hydroxy-3-methoxyphenyl)-1-(4-hydroxyphenyl)-hepta-4E,6E-dien-3-one] (2). 2 showed cytotoxicity at 4.9 and 11.4 $\mu$g/mL ($IC_{50}$) against human nonsmall cell lung cancer A549 and human melanoma SK-Mel-2, respectively, determined by SRB colorimetric method. During purification-(4-hydroxyphenyl)-4-hydroxyhexan-2-one (4) together with three known diarylheptanoids was also isolated. Their structures were determined from interpretation of spectroscopic data (IR, UV, MS, and NMR) and synthesis confirmed the structure of 2.

• 한국자기학회지
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• 제3권2호
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• pp.125-129
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• 1993

강자성 공명 실험을 사용하여 고주파 마그네트론 스파터링 방법으로 제작된 $Co_{79}Cr_{21}(at.%)$ 박막의 자기적 특성을 조사하였다. $Co_{79}Cr_{21}$ 박막은 $K=2.91{\times}10^{5}\;erg/cm^{3},\;H_{k}'=2526\;Oe,\;g=2.17$인 특성을 보이며, Q-band 강자성 공명 실험 결과와 토오크 실험결과는 서로 잘 일치함을 볼 수 있었다.

• 약학회지
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• 제38권4호
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• pp.425-429
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• 1994

The genuine aglycone, 20(S)-protopanaxadiol, obtained from the leaves of Panax ginseng as a result of direct alkaline treatment was isolated and characterized by spectroscopic evidences. The study on the yield of genuine aglycone which is produced from the treatment of some kinds of alkali was carried out. $Ginsenoside-Rh_2$ was synthesized by conjugation of 2,3,4,6-tetra-O-acetyl-${\alpha}$-D-glucopyranosyl bromide to 20(S)-protopanaxadiol in the presence of silver carbonate and cadmium cabonate. The preparation of $ginsenoside-Rh_2$ by this method is a new one which the yield of this saponin can be improved in the mild condition.

• Natural Product Sciences
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• 제13권1호
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• pp.90-96
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• 2007

Bioactivity guided fractionation of the cultured filtrates of Aspergillus versicolor, which was derived from a marine sponge Petrosia sp., yielded three polyketides: decumbenones A (1),B (2), and versiol (3). These compounds were identified on the basis of 1D and 2D NMR spectroscopic and MS analysis. The absolute configuration was defined by the modified Mosher's method. The isolated compounds were tested for cytotoxicity against a panel of five human solid tumor cell lines and antibacterial activity against twenty clinically isolated methicillin-resistant strains. This is the first report on the isolation of these compounds from a marine source.

• 생약학회지
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• 제42권1호
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• pp.89-97
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• 2011

This study was conducted to investigate tyrosinase inhibitory effect, hyaluronidase inhibitory effect and antioxidant activity by DPPH radical scavenging method on the MeOH extract of 50 species medicinal plant for screening of functional properties. As a result, Chaenomeles sinensis Koehne extract among 50 species medicinal plant turned out to be having tyrosinase, hyaluronidase inhibitory effect and antioxidant activity. The major component of tyrosinase and hyaluronidase inhibitory effect was isolated from EtOAc extract of Chaenomeles sinensis Koehne. And the component of antioxidant activity was isolated from n-BuOH extract of Chaenomeles sinensis Koehne. Their structure of compounds were identified as oleanolic acid and (-)-epicatechin by spectroscopic evidence, respectively.