• Journal of Applied Biological Chemistry
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• v.54 no.1
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• pp.67-70
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• 2011

The roots of Glycyrrhiza uralensis Fisch. were extracted with 30% aqueous ethanol (EtOH), and the concentrated extract was partitioned with n-hexane, chloroform ($CHCl_3$), ethyl acetate (EtOAc), n-butanol (n-BuOH), and $H_2O$, successively. From the $CHCl_3$ fraction, four flavonoids were isolated through the repeated silica gel ($SiO_2$), octadecyl silica gel (ODS), and Sephadex LH-20 column chromatographies (c.c.). According to the results of spectroscopic data including nuclear magnetic resonance spectrometry (NMR), electron ionization mass spectrometry (EI/MS), and infrared spectroscopy (IR), the chemical structures of the compounds were determined as glabrol (1), abyssinone II (2), glabridin (3), and isoliquiritigenin (4). The flavonoids were evaluated for cytotoxic effect against human cancer cell lines, HCT-116, HepG2, HeLa, SK-OV-3, SK-BR-3, MCF-7, and SK-MEL-5. Especially, glabrol (1) and glabridin (2) showed $IC_{50}$ values of lower than $25{\mu}M$.

• Food Science and Biotechnology
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• v.18 no.1
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• pp.223-227
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• 2009

The fruits of Cornus kousa Burg. were extracted with 80% aqueous methanol (MeOH) and the concentrated extract was partitioned with ethyl acetate (EtOAc), n-butanol (n-BuOH), and $H_2O$. From the EtOAc traction, 5 triterpenoids were isolated through repeated silica gel ($SiO_2$), octadecyl silica gel (ODS), and Sephadex LH-20 column chromatography (c.c.). These compounds were determined to be ursolic acid (1), corosolic acid (2), taraxasterol (3), betulinic acid (4), and betulinic aldehyde (5) on the basis of their spectroscopic data including electronic ionization mass spectrometry, ultraviolet spectroscopy, infrared spectroscopy, and nuclear magnetic resonance. This is the first reported isolation of these compounds from this plant. Also, compounds 1, 3, 4, and 5 show a relatively high inhibitory activity against human acyl-CoA: cholesterol acyltransferase-1 (hACAT-1) with inhibition values of $52.8{\pm}0.7$, $91.1{\pm}0.4$, $93.0{\pm}0.7$, and $96.2{\pm}0.2%$ at a concentration of $100{\mu}M$, respectively.

• Journal of the Mineralogical Society of Korea
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• v.9 no.1
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• pp.7-16
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• 1996

Partially sericitized tourmaline from a pegmatite, Black Hills, South Dakota, U.S.A., was investigated using high-resolution transmission electron microscopy (HRTEM). Muscovite occurs as the only alteration product of tourmaline, and it is developed extensively as narrow veinlets along the {110} and {100} cleavage directions of tourmaline, indicating that a cleavage-controlled alteration mechanism was dominant. Muscovite was characterized mainly as two-layer polytypes with minor stacking disorder, but tourmaline is almost free of structural defects. HRTEM images of tourmaline-muscovite interfaces revealed that the interfaces between two minerals are composed of well-defined {110} and {100} boundaries of tourmaline. The (001) of muscovite is in general parallel to the c-axis of tourmaline, but tourmaline and replacing muscovite do not show specific crystallographic orientation relationship; muscovite consists of numerous 100-1000$\AA$ thick subparallel packets, and the angles between the (001) of muscovite and (110) of tourmaline is highly variable. Al/Si ratios of both minerals suggest that tourmaline to muscovite alteration by late magnetic fluids has been facilitated by their similar Al/Si ratio in the incipient alteration stage, in that the hydration reaction with preservation of Al and Si would require only addition of K+ and H2O. Aluminous minerals other than muscovite were not characterized as the alteration products of tourmaline, indicating that tourmaline reacted directly to muscovite; the tourmaline alteration apparently occurred by the presence of residual fluids in which K+ is available and silica was not undersaturated.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.5
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• pp.127-132
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• 2018

The amount of generated Circulating Fluidized Bed Combustion ash (CFBC ash) is annually increasing, but most CFBC ash has been landfilled and discarded due to the limited utilization. The major chemical compositions of CFBC ash are $SiO_2$, CaO and $CaSO_4$, which could form hydration products by reacting with water as self-cementing property such as cement. The purpose of the this study is to derive the optimal mix proportions to improve polymer-modified mortar with the use of CFBC ash which has the self-cementing property. In order to develop polymer-modified mortar, three mix proportions were determined, and fundamental properties for the mixtures were obtained. As a result, the optimal mixture containing 10 percent of silica fume, 1.0 percent of polymer and 3.5 percent of expansive additives were proposed in this study.

• Journal of the Korean Ceramic Society
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• v.22 no.1
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• pp.35-39
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• 1985

Synthetic mica $NaMg_{2.5}(Si_4O_{10})F_2 (Na-TSM)$ was treated with HCl solution and H-type exchange resin to investigate the chemical stability and the ion exchange by measuring the dissolution of chemical components and the exchanged $H^+$ ion. The replacement of $Na^+$ ion occurred in contact with HCl solution and H-type ion exchange resin at the surface of Na-TSM particles reached $Na^+$ ions at maximum value of 70~80%. $Mg^{2+}$ ion of octahedral layer became to dissolve from the pH2 solution and th amount of it dissolved in-creased almost proportional to $H^+$ ion concentration from around 0.02N $H^+$ ion equilibrium concentration. The crystalline structure of Na-TSM was destructed by dissolution of Mg2+ ion in cncentrated hydrochloric acid solution and resulted silica gel precipitation.

• Transactions of the Korean hydrogen and new energy society
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• v.24 no.5
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• pp.359-366
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• 2013

This work is investigated for the catalytic decomposition of hydrogen iodide (HI). Platinum was used as active material by loading on $ZrO_2-SiO_2$ mixed oxide in HI decomposition reaction. To obtain high and stable conversion of hydrogen iodide in severe condition, it was required to improve catalytic activity. For this reason, a method increasing dispersion of platinum was proposed in this study. In order to get high dispersion of platinum, zirconia was incorporated in silica by sol-gel synthesis. Incorporating zirconia influence increasing platinum dispersion and BET surface area as well as decreasing deactivation of catalysts. It should be able to stably product hydrogen for a long time because of inhibitive deactivation. HI decomposition reaction was carried out under the condition of $450^{\circ}C$ and 1 atm in a fixed bed reactor. Catalysts analysis methods such as $N_2$ adsorption/desorption analysis, X-ray diffraction, X-ray fluorescence, ICP-AES and CO gas chemisorption were used to measurement of their physico-chemical properties.

• Journal of Korea Foresty Energy
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• v.20 no.2
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• pp.1-8
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• 2001

The 90% methanol extracts of eight magnoliaceae plants were collected and tested the cytotoxicity against SK-OV-3 and SiHa cells. Also six pure compounds such as magnonol, honokiol, dihydroxybiphenyl ether, linodenine, anonaine, asimilobine which were previously isolated from Magnolia obovata Thunb. were evaluated the cytotoxicities and their mechanism study using the Lactate dehydrogenase assay(LDH) and FACScan analysis system. Of the tested six compounds, magnonol, honokiol, dihydroxybiphenyl ether showed high cytotoxicities against human cancer cell lines, SK-OV-3 and SiHa cells. In addition, one of the plausible mechanisms of their antitumor activities suggested that they could induce the early stage of apoptosis. For the quantitative analysis, the methanol extractives were fractionated with chloroform, ethylacetate, $H_2O$ and then the ethylacetate fraction was chromatographed on silica gel using n-Hexane ; Acetone(4:1, v/v) as eluent. This fraction was subjected for the quantitative analysis in the HPLC system. The result suggested that the methanol extractives of Magnolia obovata Thunb. contained with magnonol, honokiol, dihydroxybiphenyl ether, 0.9%, 0.3% and 0.24%, respectively.

• Korean Journal of Pharmacognosy
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• v.31 no.1
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• pp.95-100
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• 2000

In order to find out hypoglycemic constituents from natural resources, Korean medicinal plants being used for the treatments of diabetes mellitus were tested with streptozotocin-induced diabetic rats. From the above screening, the $CH_2Cl_2$ fraction of 80% methanol extracts of Morus alba leaves showed hypoglycemic activity. The $CH_2Cl_2$fraction was chromatographed on silica gel, resulting in 9 subfractions, and tested hypoglycemic activity. The subfraction which had a strong hypoglycemic activity was rechromatographed and two galactolipids (compounds 1 and 2) were isolated along with a triterpene (compound 3) from other fractions. On the basis of spectroscopic data, acid hydrolysis, alkaline hydrolysis and enzyme hydrolysis results, compounds 1, 2 and 3 were identified as $1-O-(9Z,12Z,15Z-octatrienoyl)-2-O-(9Z,12Z,15Z-octatrienoyl)-3-O-{\beta}-D-galactopyranosyl$ glycerol, $2(R)-1-O-octadecanoyl-2-O-(9Z,12Z,15Z-octatrienoyl)-3-O-{\beta}-D-galactopyranosyl$ glycerol, and $3{\beta}-hydroxylup-20(29)-ene$ acetate, respectively. Compound 2 (1mg/kg p.o.) has approximately 16% hypoglycemic activity in streptozotocin-induced diabetic rats.

• Journal of the Korean Ceramic Society
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• v.27 no.3
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• pp.394-400
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• 1990

Mullite and cordierite were prepared by the sol-gel route. Boehmite, fumed silica and Mg(NO3)2$.$6H2O were their starting materials. Mullite and cordierite powder were mixed by various weight percent. These mixed sols were ball-milled for 48hrs, dried at 100$^{\circ}C$, pressed, cold isostatic pressed and sintered at 1490$^{\circ}C$ for 2hrs. Mullite-cordierite composites sintered at 1490$^{\circ}C$ for 2hrs had>98% of theoretical density. Bending strength of the sintered bodies were 329-249MPa, dielectric constant 7.1-6.7 at 1MHz and thermal expansion coefficient at 800$^{\circ}C$ was matched with Si in the range of 30-35wt% cordierite.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.3
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• pp.171-177
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• 2007

This study suggested a new method to stabilize molten salt wastes generated from the pyre-process for the spent fuel treatment. Using conventional sol-gel process, $SiO_2-Al_2O_3-P_2O_5$ (SAP) inorganic material that is reactive to metal chlorides were prepared. In this paper, the reactivity of SAP with the metal chlorides at $650{\sim}850$, the thermal stability of reaction products and their leach-resistance under the PCT-A test method were investigated. Alkali metal chlorides were converted into metal aluminosilicate($LixAlxSi1-_xO_{2-x}$) and metal phosphate($Li_3PO_4\;and\;Cs_2AlP_3O_{10}$) While alkali earth and rare earth chlorides were changed into only metal phosphates ($Sr_5(PO_4)_3Cl\;and\;CePO_4$). The conversion rate was about $96{\sim}99%$ at a salt waste/SAP weight ratio of 0.5 and a weight loss up to $1100^{\circ}C$ measured by thermogravimetric analysis were below 1wt%. The leach rates of Cs and Sr under the PCT-A test condition were about $10^{-2}g/m^2\;day\;and\;10^{-4}g/m^2\;day$. From these results, it could be concluded that SAP can be considered as an effective stabilizer for metal chlorides and the method using SAP will give a chance to reduce the volume of salt wasteform for the final disposal through further researches.