• Korean Membrane Journal
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• v.3 no.1
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• pp.51-58
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• 2001

The surface of Poly(ether imide) (PEI) membranes has been sulfonated using CIS03H. The resulting membranes were characterized through the analysis of ESCA and contact angle measurements The sulfonated PEI membranes were exposed to gases of $O_2$, $N_2$, and $CO_2$ to measure the permeation rates and ideal separation factors. In addition, the diffusivities and solubilities of individual gases were measured. The diffusivity effect is more dominant than the solubility one on gas transports.

• Membrane Journal
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• v.13 no.3
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• pp.182-190
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• 2003

Carbon molecular sieve (CMS) membranes were prepared by the pyrolysis of polyvinylpyrrolidone containing polyimide precursors. We have prepared the polymer precursors, pyrolyzed polymer and investigated the effect of pyrolyzing polymer on the characteristics of carbon structures and gas separation properties of the CMS membranes. Thermogravimetric analysis (TGA) showed the two-step decomposition of polymer precursor. First decomposition of the pyrolyzing polymer began around $400^{\circ}C$ while carbonizing polymer showed the decomposition around $550^{\circ}C$. The gas permeabilities through the CMS membranes were enhanced by the introduction of the pyrolyzing polymer and decreased with increased final pyrolysis temperature. The CMS membrane pyrolyzed at $550^{\circ}C$. derived from precursor containing 5wt% PVP as a pyrolyzing polymer showed gas permeability for $O_2$ of 808 Barrers [$10^{-10}cm^3 (STP)cm/cm^2scmHg]$ and $O_2/N_2$ selectivity of 7.

• Archives of Pharmacal Research
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• v.21 no.2
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• pp.217-222
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• 1998

A stereospecific HPLC method has been developed for the resolution of the enantiomers of salbutamol in human urine. After solid-phase extraction and derivatization with 2,3,4,6-tetra-O-acetyl-$\beta$-D-glucopyranosyl isothiocyanate, the diastereomeric derivatives were resolved (Rs=1.83) on $5{\mu}m$ octadecylsilan column using 35% acetonitrile in 0.05M ammonium acetate buffer (pH=6) as a mobile phase with electrochemical detection. The diastereomeric derivatives were formed within 30 min. The detection limit of each enantiomer was 20 ng/ml (S/N=3).

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.4
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• pp.267-272
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• 2007

Various kinds of RI wastes are discharged from licensed organizations of radioisotopes les such as hospitals and clinic organizations, educational organizations, research institutions, and public organizations. Radioiodines such as $^{125}I\;and\;^{131}I$ are radioisotopes mainly used in nuclear medicine and industry. A method for the determination of radioiodines in RI wastes has been applied to measure low level activity using acid decomposition method and HPGe gamma ray spectrometer. Prior to analysis of real samples, $^{131}I$ reference solution and 10 g of yellow tissue paper was added to flask in mantle and was heated in 100 mL of 0.4 N $K_2Cr_2O_7$ and 100 mL of 9 M $H_2SO_4$, and then distilled after adding 10 mL of 30% $H_2PO_3$ and 1 mL of 30% $H_2O_2$. The condensed iodine by circulator was extracted into $CCl_4$, then back-extracted into the aqueous phase with 10 mL of 5% $K_2SO_2$ solution. Finally, $^{131}I$ was measured at 364.48 keV using HPGe gamma ray spectrometer after precipitation and filtration. Chemical yield of three steps such as acid decomposition process, chemical separation process, and precipitation and filtration process was more han 94% respectively, MDA(Minimum Detectable Activity) of $^{131}I$ at this analytical condition was 0.6 Bq/g.

• Archives of Pharmacal Research
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• v.28 no.8
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• pp.892-896
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• 2005

In order to isolate substances that inhibit the hemolytic activity of human serum against eryth-rocytes, we have evaluated whole plants of the Orostachys japonicus species with regard to its anti-complement activity, and have identified its active principles following activity-guided isolation. A methanol extract of the O. japonicus, as well as its n-hexane soluble fraction, exhibited significant anti-complement activity on the complement system, which was expressed as total hemolytic activity. A bioassay-guided chromatographic separation of the constituents resulted in the isolation of three known compounds 1-3 from the active n-hexane fraction. The structure of these compounds were analyzed, and they were identified as hydroxyhopanone (1), $\beta-sitosteryl-3-O-\beta-D-glucopyranosyl-6'-O-palmitate$ (2), and $\beta-sitosteryl-3-O-\beta-D-glucopyranoside$ (3), respectively. Of these compounds, compound 2 exhibited potent anti-complement activity $(IC_{50}=1.0\pm0.1{\mu}M)$ on the classical pathway of the complement, as compared to tiliroside $(IC_{50}=76.5\pm1.1{\mu}M)$, which was used as a positive control. However, compounds 1 and 3 exhibited no activity in this system.

• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1143-1148
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• 2010

We investigated the separation of nitrogen heterocyclic compound (NHC) contained in a model coal tar fraction comprising four kinds of NHC [indole (In), quinoline (Q), iso-quinoline (iQ), quinaldine (Qu)], three kinds of bicyclic aromatic compound (BAC) [1-methylnaphthalene (1MN), 2-methylnaphthalene (2MN), dimethylnaphthalene (DMN) mixture with ten structural isomers (DMNs; regarded as one component)], biphenyl (Bp) and phenyl ether (Pe) by liquid membrane permeation (LMP). A batch-stirred tank was used as the permeation unit. An aqueous solution of saponin and n-hexane were used as the liquid membrane and the outer oil phase, respectively. Yield and selectivity of individual NHC was much larger than that of BAC, Bp and Pe. Increasing the initial mass fraction of the saponin to the membrane solution ($C_{sap,0}$) and the initial volume fraction of O/W emulsion to total liquid in a stirred tank (${\phi}_{OW,0}$) resulted in deteriorating the yield of individual NHC, but increasing the stirring speed (N) resulted in improving the yield of each NHC. With increasing $C_{sap,0}$, the selectivity of each NHC based on DMNs increased. Increasing ${\phi}_{OW,0}$ and N resulted in decreasing the selectivity of individual NHC based on DMNs. At an experimental condition fixed, the sequence of the yield and selectivity in reference to DMNs for each NHC was Q > Qu = iQ > In. Furthermore, we compared LPM method with methanol extraction method in view of the separation efficiency (yield, selectivity) of NHC.

• Journal of environmental and Sanitary engineering
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• v.15 no.3
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• pp.70-74
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• 2000

The technology of malodorous substances treatment was classified physical separation and chemical destruction. This study was carried out to investigate the characteristics of malodorous substances treatment with the change of operating conditions from the ozone generator. The major results of this study were as follows : Removal efficiency by additive ozone rate was measured $NH_3$:95%(ozone additive rate : 2), $H_2S$ : 97%(ozone additive rate:4), $CH_3SH$ : 96%(ozone additive rate : 3), $(CH_3)_2S_2$ : 97%(ozone additive rate:5), $(CH_3)_3N$ : 95%(ozone additive rate : 1), $CH_3CHO$ : 95%(ozone additive rate : 2), $C_6H_5CHCH_2$ : 95%(ozone additive rate : 2).

• Bulletin of the Korean Chemical Society
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• v.33 no.8
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• pp.2546-2552
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• 2012

A novel biguanide-functionalized $Fe_3O_4/SiO_2$ magnetite nanoparticle with a core-shell structure was developed for utilization as a heterogeneous organosuperbase in chemical transformations. The structural, surface, and magnetic characteristics of the nanosized catalyst were investigated by various techniques such as transmission electron microscopy (TEM), powder X-ray diffraction (XRD), vibrating sample magnetometry (VSM), elemental analyzer (EA), thermogravimetric analysis (TGA), $N_2$ adsorption-desorption (BET and BJH) and FT-IR. The biguanide-functionalized $Fe_3O_4/SiO_2$ nanoparticles showed a superpara-magnetic property with a saturation magnetization value of 46.7 emu/g, indicating great potential for application in magnetically separation technologies. In application point of view, the prepared catalyst was found to act as an efficient recoverable nanocatalyst in nitroaldol and domino Knoevenagel condensation/Michael addition/cyclization reactions in aqueous media under mild condition. Additionally, the catalyst was reused six times without significant degradation in catalytic activity and performance.

• Proceedings of the Membrane Society of Korea Conference
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• 1995.09a
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• pp.21-22
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• 1995

Gas separation science and technology is among the most rapidly growing areas involving membrane-based processes. Nitrogen enrichment of air, hydrogen recovery from a broad array of stream types, and removal of acid gases from natural gases are typical of the applications in this field. Great progress has been made in the discovery of guidelines optimization of polymer structures with simultaneously high permeabilities and selectivities for these important gas pairs. The development of thin-skinned asymmetric hollow fibers have also provided structures with extremely high permeation fluxes. Especially in the case of O$_{2}$/N$_{2}$ separations, the rate of improvements in new polymeric materials for gas separations appears to be slowing to a halt. Evidence will be presented, however, that the practical tradeoff between membrane permeability and selectivity has not been reached.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1158-1164
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• 2011

5-Methoxy-N,N-diisopropyltryptamine (5-MeO-DIPT), a psychoactive tryptamine derivative, is a hallucinogenic drug of abuse. In this study, 5-OH-DIPT and its metabolites were identified and the quantitative method was developed and validated by using hydrophilic interaction chromatography-tandem mass spectrometry (HILICMS/MS). Chromatographic separation was achieved on an Atlantis HILIC silica column ($5{\mu}m$, $100{\times}2.1\;mm$). The metabolites of 5-MeO-DIPT in rat urine were characterized via Q1 scanning and product ion scanning. As a consequence, 5-MeO-IPT, 5-OH-DIPT, 6-OH-5-MeO-DIPT and their glucuronide conjugates were detected and identified as the metabolites of 5-MeO-DIPT. Subsequently, a quantitative method for 5-MeO-DIPT and its major metabolites, 5-MeO-IPT and 5-OH-DIPT, was developed in multiple reactions monitoring (MRM) mode. The calibration curves for all analytes evidenced good linearity over the concentration range of 1-1000 ng/mL with linear correlation co-efficients ($r^2$) in excess of 0.99. The intra- and inter-day accuracy and precision were 92.2-110.2% and 1.5-9.9%, respectively.