• Journal of Powder Materials
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• v.15 no.1
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• pp.23-30
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• 2008

Ni-20Cr-20Fe-5Nb alloy with or without $Y_2O_3$ was manufactured by mechanical alloying process and consolidated by spark plasma sintering (SPS). The grain size of the alloy with $Y_2O_3$ was smaller than that of alloy without $Y_2O_3$ which results from the effect of $Y_2O_3$ suppressing grain growth. The tensile strength at room temperature was increased by the addition of $Y_2O_3$ but decreased abruptly at temperature above $600^{\circ}C$. It seems to result from the change of deformation mechanism due to fine grain size, that is, grain boundary sliding is predominant at above $600^{\circ}C$ while internal dislocation movement is predominant at below $600^{\circ}C$. After conventional heat treatment process of solution treatment and aging, a small amount of ${\delta}(Ni_3Nb)$ phase was formed in Ni-20Cr-20Fe-5Nb alloy while a large amount of ${\gamma}"(Ni_3Nb)$ was formed in Inconel 718 in the previous report. This is due to exhaustion of Nb content by the formation of NbC during consolidation.

• Applied Biological Chemistry
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• v.36 no.2
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• pp.99-104
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• 1993

In order to explore the brassinosteroid-active component in Cassia tora, methanol extract of immature seeds was purified by sequences of solvent fractionation, silica gel adsorption chromatography, Sephadex LH-20 chromatography, charcoal adsorption chromatography and Bondesil chromatography. The activity of brassinosteroid was monitored by the rice inclination test and its presence could be confirmed in each purification step. The purified active components were separated by silica gel adsorption chromatography. Brassinosteroid substances in separated active fractions were identified as teasterone, castasterone, brassinolide by TLC and HPLC. Our work is probably the first report of endogenous brassinosteroid in Cassia tora. The content of brassinosteroid in Cassia tora as converted into brassinolide was $3.5{\sim}5.5\;ng/g$ fresh weight. The order of brassinosteroid contents was toward to be teasterone, castasterone, brassinolide.

• Applied Biological Chemistry
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• v.48 no.3
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• pp.263-266
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• 2005

Cymbidium goeringii REICHB. fil was extracted with 80% MeOH and solvent-fractionated with EtOAc, n-BuOH and $H_2O$, successively. From EtOAc fraction, three sterols were isolated on repeated silica gel and ODS column chromatographies. The chemical structures were determined as ${\beta}-sitosterol$ (1), daucosterol (2) and ergosterol peroxide (3) by NMR, MS and IR, which is the first to be isolated from Cymbidium goeringii REICHB. fil.

• Journal of Applied Biological Chemistry
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• v.61 no.2
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• pp.131-134
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• 2018

The stem of Chrysanthemum morifolium, 'Baekma', were repeatedly extracted with 80% aqueous MeOH and the concentrates was partitioned into ethyl acetate (EtOAc), n-butyl alcohol and $H_2O$ fraction. The repeated silica gel and octadecyl silica gel column chromatographies for the EtOAc fractions led to isolation of two glycosyl glycerides. The chemical structures of the compounds were determined as (2S)-1-O-${\beta}-{\text\tiny{D}}$-galactopyranosyl-2,3-dilinoleoylglycerol (1) and (2S)-1-O-${\beta}-{\text\tiny{D}}$-galactopyranosyl-2,3-dipalmitoylglycerol (2) based on spectroscopic data anlyses including nuclear magnetic resonance, mass sperctrometry, and infrared spectrometry and gas chromatography mass spectrometry.

• Korean Journal of Environmental Agriculture
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• v.25 no.4
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• pp.359-364
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• 2006

Reversed-phase high-performance liquid chromatography (HPLC) techniques were developed to quantify abamectin (ABM) in paprika (Capsicum annum). Separation was achieved on a $C_{18}$ ODS column with a mobile phase of acetonitrile/water (96/4, v/v) mixture in an isocratic elution at the flow tate of 1.2 mL/min for avermectins (AVMs). The retention times were 8.0 and 9.7mins for AVM $B_{lb}$ and AVM $B_{1a}$, respectively. Residual AVMs (sum of AVM $B_{1a}$, AVM $B_{1b}$ and 8,9-Z-AVM $B_{1a}$) in the vegetable were extracted with acetonitrile, and the silica solid-phase extraction cartridges were used to purify the extract. AVMs were derivatized using trifluoroacetic acid and 1-methylimidazole, and the derivatives were determined with a fluorescence detector (excitation at 365 nm and emission at 470 nm). High and consistent recoveries, ranging from 93% to 115%, were obtained for AVM $B_{1a}$ and 8, 9-Z-AVM $B_{1a}$ at fortified levels of $20{\mu}g/kg\;and\;200{\mu}g/kg$ for paprika. The limit of quantitation (LOQ) was $2{\mu}g/kg$. The residual levels of AVMs in paprika in a field experiment from one day to seven days after the last application decreased from 18.40 to $7.59{\mu}g/kg$. The half-life $(T_{1/2})$ of AVMs in paprika was 1.47 days.

• The Korean Journal of Food And Nutrition
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• v.11 no.3
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• pp.347-353
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• 1998

An antibiotic for methicillin resistant Staphylococcus aureus(MRSA) produced by Streptomyces lydicus YSK-681 was extracted by chloroform, and then purified by the C18 reversed-phase HPLC and silica gel column HPLC. The molecular weight of the purified antibiotic was determined from the FAB analysis MS an m/z 1022.4 and 1036.4(M+H)+, indicating that the isolated antibiotic consisted of two similar compounds with the molecular weight difference of 14 m/z value. With the aid of the various nuclear magnetic resonance(NMR) spectroscopic techniques such as 1H NMR, 13C NMR, DEPT and HMQC spectroscopy, the characteristics of function al groups were deduced as the hydroxyl group and leucine. The MIC values of the purified antibiotic were observed at 1∼32 $\mu\textrm{g}$/$m\ell$ against Gram-positive bacteria compared to > 125 $\mu\textrm{g}$/$m\ell$ against Gram-negative bacteria or fungi. The antibiotic was active at 8 $\mu\textrm{g}$/$m\ell$ of MIC90 and S180 at the concentration of 500 $\mu\textrm{g}$/$m\ell$.

• Asian Journal of Atmospheric Environment
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• v.11 no.4
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• pp.283-299
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• 2017

An analytical method using high-performance liquid chromatography (HPLC) with fluorescence (FL) detection was developed for simultaneously analyzing 10 polycyclic aromatic hydrocarbons (PAHs) and 18 nitro-derivatives of PAHs (NPAHs). The two-dimensional HPLC system consists of an on-line clean-up and reduction for NPAHs in the 1st dimension, and separation of the PAHs and the reduced NPAHs and their FL detection in the 2nd dimension after column-switching. To identify an ideal clean-up column for removing sample matrix that may interfere with detection of the analytes, the characteristics of 8 reversed-phase columns were evaluated. The nitrophenylethyl (NPE)-bonded silica column was selected because of its shorter elution band and larger retention factors of the analytes due to strong dipole-dipole interactions. The amino-substituted PAHs (reduced NPAHs), PAHs and deuterated internal standards were separated on polymeric octadecyl-bonded silica (ODS) columns and by dual-channel detection within 120 min including clean-up and reduction steps. The limits of detection were 0.1-9.2 pg per injection for PAHs and 0.1-140 pg per injection for NPAHs. For validation, the method was applied to analyze crude extracts of fine particulate matter ($PM_{2.5}$) samples and achieved good analytical precision and accuracy. Moreover, the standard reference material (SRM1649b, urban dust) was analyzed by this method and the observed concentrations of PAHs and NPAHs were similar to those in previous reports. Thus, the method developed here-in has the potential to become a standard HPLC-based method, especially for NPAHs.

• Journal of Powder Materials
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• v.20 no.4
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• pp.269-274
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• 2013

The present work investigated the dispersion behavior of $Y_2O_3$ particles into AISI 316L SS manufactured using laser cladding technology. The starting particles were produced by high energy ball milling in 10 min for prealloying, which has a trapping effect and homogeneous dispersion of $Y_2O_3$ particles, followed by laser cladding using $CO_2$ laser source. The phase and crystal structures of the cladded alloys were examined by XRD, and the cross section was characterized using SEM. The detailed microstructure was also studied through FE-TEM. The results clearly indicated that as the amount of $Y_2O_3$ increased, micro-sized defects consisted of coarse $Y_2O_3$ were increased. It was also revealed that homogeneously distributed spherical precipitates were amorphous silicon oxides containing yttrium. This study represents much to a new technology for the manufacture and maintenance of ODS alloys.

• 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 $25{\mu}M$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.5A
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• pp.451-459
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• 2007

RFID it reads information which is it writes, the semiconductor chip for and the radio frequency system which uses the hazard antenna it has built-in transmission of information it talks. Formation which is transmitted like this collection and America which it filtrates wey the RFID search service back to inform the location of the server which has commodity information which relates with an object past record server. The hazard where measurement analysis result the leader for electronic interference does not occur consequently together from with verification test the power level which is received from the antenna grade where it stands must maintain minimum -55dBm and the electronic interference will not occur with the fact that, antenna and reel his recognition distance the maximum 7m until the recognition which is possible but smooth hazard it must stand and and with the fact that it will do from within and and and 3-4m it must be used Jig it is thought.