• 한국안전학회지
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• 제5권2호
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• pp.32-39
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• 1990

The ${\gamma}$-Fe$_2$O$_3$ compounds were oxidized in the furance after gas detecting sensor made molding as the Fe$_3$O$_4$ the synthesized Fe$_3$O$_4$, by ferrous sulfate and sodium hydroxide. Their sensities on carbon monoxide, ethyl alcohol and L. P. G. were measured at various temperatures, respectively. And then their electrical resistivities, thermal properties (D.T.A. ＆ T.G.A.), were examined about their having an effet on the gas-sensing in company with the effect of pure ${\gamma}$-Fe$_2$O$_3$ and the detecting sensor ${\gamma}$-Fe$_2$O$_3$, which reacts with $K_2$CO$_3$ in the hydrothermal coundition, and the electrical conductive mechanism was reflected simultaneously. It was observed that the electrical conductivities and response ratios showed highest value at the endothermic temperature part, 300~35$0^{\circ}C$ of D.T.A.―curve. Consequently, the response ratios and response times of the hydrothermal detecting sensor were higher than that of pure detecting sensor, the specific surface areas were the highest at the endothermic range of D.T.A.-curve. These response ratios of detecting sensor for $K_2$CO$_3$, process at hydrothermal condition on carbon monoxide appeared higher than that on ethyl alcohol and in case of L.P.G. last.

• 한국분말재료학회지
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• 제18권1호
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• pp.29-34
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• 2011

In order to increase the coercivity of (Nd, Dy)-Fe-B sintered magnets without much reduction of remanence, small amount of Dy compounds such as $Dy_2O_3$ and $DyF_3$ was mixed with (Nd, Dy)-Fe-B powder. After mixing, the coercivity of (Nd, Dy)-Fe-B sintered magnets apparently increased with the increase of Dy compound in the mixture. Addition of $DyF_3$ was more effective than $Dy_2O_3$ for the improvement of coercivity. Reduction of the remanence by the addition of Dy compound, however, was larger than expected mostly due to unresolved coarse Dy compound in the magnet. EPMA analysis revealed that Dy was diffused throughout the grains in the magnet mixed with $DyF_3$ whereas Dy was rather concentrated around grain boundaries in the magnet mixed with $Dy_2O_3$.

• Advances in materials Research
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• 제2권3호
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• pp.173-180
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• 2013

Lead-free complex perovskite ceramics $NaMeO_3$ ($Me{\equiv}Nb$, Ta) were synthesized using conventional solid state reaction technique and characterized by structural, FTIR and electrical (dielectric and ac conductivity) studies. The crystal symmetry, space group and unit cell dimensions were determined from the experimental results using FullProf software. XRD analysis of the compound indicated the formation of single-phase orthorhombic structure with the space group Pmmm (47). Dielectric studies showed the diffuse phase transition at $394^{\circ}C$ for $NaNbO_3$ and $430^{\circ}C$ for $NaTaO_3$. Ac conductivity in both the compounds follows Jonscher's power law.

• Investigative Magnetic Resonance Imaging
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• 제10권1호
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• pp.20-25
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• 2006

목적 : 새로 개발한 상자성 복합체의 자기이완 특성을 조사해 보고자 하였다. 대상 및 방법 : DMF(15 mL)와 DTPA-bis-anhydride(0.71g, 2 mmol)의 서스펜션 용액에 4-aminomethylcyclohexane carboxylic acid(0.63g, 4 mmol)를 넣어 리간드를 합성한 후 Gd2O3(0.18g, 0.5 mmol)을 넣어 최종적인 Gd 착화물을 합성하였다. 상자성 복합체의 자기이완율을 측정하기 위해 상자성 복합체를 3차 증류수를 사용하여 1 mM로 희석시켰으며 1.5T(64 MHz)에서 자기이완 시간을 측정하였다. T1 자기이완시간을 측정하기 위하여 반전 회복(inversion-recovery) 펄스열을 사용하였으며 T2 자기이완시간은 CPMG(Carr-Purcell-Meiboon-Gill) 펄스열을 사용하였다. 자기이완 시간 및 자기이완율을 영상으로 표현한 T1 자기이완 지도, R1 지도, T2 자기이완 지도 및 R2 지도를 구현 하였다. 결과 : 현재 시판중인 상자성 조영제인 Omniscan(Gadodiamide)의 $R1=4.9mM^{-1}sec^{-1},\;R2=4.8mM^{-1}sec^{-1}$에 비해 R1의 경우 SUK090(Gd-C32H74N5O24)는 $12.46mM^{-1}sec^{-1}$, SUK091(Gd-C34H78N5O24)는 $12.77mM^{-1}sec^{-1}$의 값을 나타낸 반면 SUK092(Gd-C30H56N5O17)는 $2.09mM^{-1}sec^{-1}$로 자기이완율이 감소하였다. R2의 경우 SUK090(Gd-C32H74N5O24)는 $8.76mM^{-1}sec^{-1}$, SUK091(Gd-C34H78N5O24)는 $7.60mM^{-1}sec^{-1}$의 값을 나타낸 반면 SUK092(Gd-C30H56N5O17)는 $1.82mM^{-1}sec^{-1}$로 감소 하였다. 결론 : 본 연구에서 합성한 상자성 복합체중 SUK090(Gd-C32H74N5O24)와 SUK091(Gd-C34H78N5O24)는 기존의 상자성 조영제에 비해 T1, T2 자기이완율이 크고 결과적으로 T1/T2 조영증강 효과가 클 것으로 예상된다.

• 대한환경공학회지
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• 제34권2호
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• pp.73-78
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• 2012

낙동강 원수와 급속 사여과 처리수중에 함유된 인공 사향물질(Synthetic Musk Compounds, SMCs) 3종에 대해 오존처리 공정에서의 제거특성을 살펴본 결과, Musk Ketone (MK)이 AHTN (7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene)과 HHCB (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[c]-2-benzopyran)에 비해 오존처리에 의한 제거율이 낮게 나타났다. 그리고 동일한 운전조건에서 원수에 함유된 SMCs의 제거율은 원수 중에 함유된 오존 소모물질들에 의한 영향으로 급속 사여과처리수에 함유된 경우보다 제거율이 훨씬 낮았다. 오존 투입농도 0.5~10.0 mg/L에서 낙동강 원수와 급속 사여과 처리수 중에 함유된 3종의 SMCs에 대한 제거 속도상수(k)는 오존 투입농도가 증가할수록 급격히 증가하는 경향을 나타내었고, 반감기 역시 오존 투입농도 증가에 비례하여 급격히 감소하였다. 전/후오존 공정이 갖추어진 낙동강 하류에 위치한 정수장들의 경우, 전오존 공정은 최대 1.5~2.0 mg/L의 오존 투입농도로 2~4분 및 후오존 공정은 최대 2.0~2.5 mg/L의 오존 투입농도로 6~8분 정도의 체류시간을 가지도록 설계되어져 있어 비교적 고농도의 SMCs가 유입될 경우에는 오존처리만으로는 이들 물질들에 대한 제어가 어려운 것으로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제30권11호
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• pp.1769-1776
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• 2020

As part of our current work to discover structurally and/or biologically novel compounds from Korean wild mushrooms, we isolated five ergostane-type steroids (1-5) from the fruiting bodies of Xerula furfuracea via repeated column chromatographic separations and HPLC purification. The chemical structures of the isolated steroids were shown to be (22E,24R)-24-methylcholesta-4,22-diene-3,6-dione (1), ergosta-7,22-diene-3β,5α,6β-triol (2), ergosta-7,22-diene-3β,5α,6β,9α-tetraol (3), (22E,24R)-5α,8α-epidioxyergosta-6,22-diene-3β-ol-3-O-β-D-glucopyranoside (4), and (22E,24R)-5α,8α-epidioxyergosta-6,9,22-triene-3β-ol-3-O-β-D-glucopyranoside (5)based on comparison of the data regarding their spectroscopic and physical properties with those of previous studies. Notably, this is the first report on the presence of the identified steroids (1-5) in this mushroom. We tested compounds 1-5 to determine their effects on adipogenesis and osteogenesis in the mouse mesenchymal stem cell line C3H10T1/2 and found that compounds 4 and 5 suppressed the differentiation of stem cells into adipocytes. Notably, in addition to its suppressive effect on adipogenesis, compound 5 was also shown to promote the osteogenic differentiation of stem cells. These findings demonstrate that the bioactive compounds isolated might be effective for the treatment of menopause-associated syndromes, such as osteoporosis and obesity, as the isolated compounds were shown to suppress adipogenesis and/or promote osteogenesis of stem cells.

• 한국물환경학회지
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• 제26권2호
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• pp.303-310
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• 2010

Recently distinguished AOP means technology resolving organic compounds in water to harmless compounds such as $CO_2$ and $H_2O$ by creating OH radical ($OH{\cdot}$) with more powerful oxidation than general oxidants. It has merits which the 2nd pollution is not caused since it uses solar energy, sludge doesn't take place, it can be applied to high-density waste water and it oxidizes non-biodegradable organic compounds more easily. The purpose of the study was to examine about removable characteristics of phenol which was a non-biodegradable organic matter with UV/$O_3$/Catalyst processes which is one out of AOP and to present applicability of photocatalyst and the optimum conditions of treatment. The study regarded initial phenol concentration, initial pH, photocatalyst amount and flow as its conditions. As the results, the test had the highest removable efficiency (92%) when initial phenol concentration was 100 mg/L, initial pH 7, photocatalyst amount 6L and flow 1.5 mg/min. The removable efficiency was increased as much as initial phenol concentration was increased, when initial pH was 7 (neutrality), photocatalyst amount was increased and flow was increased. It was checked that the optimum HRT was 12 hours. Therefore, phenol is enough removable with UV/$O_3$/Catalyst process and its prospect in the future is expected.

• Natural Product Sciences
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• 제21권1호
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• pp.42-48
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• 2015

Lactuca raddeana (Compositae) is used to treat obesity and complications due to diabetes. The five phenolic compounds including chlorogenic acid, chicoric acid, luteolin 7-O-glucoside, luteolin 7-O-glucuronide, luteolin were qualitatively identified by LC-ESI-MS analysis. The contents were quantitatively determined by HPLC, under the condition of a Capcell Pak C18 column ($5{\mu}m$, $250mm{\times}4.6mm\;i.d.$) and a gradient elution of 0.05% trifluoroacetic acid (TFA) and 0.05% TFA in $MeOH-H_2O$ (60 : 40). The contents of chicoric acid (100.99 mg/g extract) and luteolin 7-O-glucoside (101. 69 mg/g extract) were high, while those of other three phenolic substances were very low. The 3T3-L1 adipocyte cells treated with chicoric acid and luteolin 7-O-glucuronide significantly suppressed the accumulation of fat, suggesting they are effective against obesity. Since high level of peroxynitrite (ONOO) causes cardiovascular disease in obese patients, its scavenging activity was also studied.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1992년도 추계학술발표강연 및 논문개요집
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• pp.16-16
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• 1992

We have studied the effect of platinum addition on the supercon ducting properties of YB $a_2$C $u_3$$O_{7-x}$ (123) compound and elucidated the mechanism of fine dispersion of $Y_2$BaCu $O_{5}$(211) particles in YB $a_2$C $u_3$$O_{7-x}$ superconductor prepared by melting method from the metallurgical point of view. In this study, BaCu $O_2$ and CuO-rich phase unreacted during the peritecitc reaction markedly decreased by the 211 powder addition. The 211 particle of Pt-fee sintered samples exhibited 8~10$\mu$m in size, but in 1wt%Pt-added sample, 211 particles were finely dispersed in 123 matrix and the size of 211 particle was about 1~2$\mu$m. And, the critical temperature( $T_{c. zero}$) of Pt doped samples was 91.5K and the transport critical current density ( $J_{c}$) of Pt-doped samples was much more than 10$^4$A/$\textrm{cm}^2$. The high $J_{c}$ and fine dispersion of 211 particles of Pt doped YB $a_2$C $u_3$$O_{7-x}$ superconductor are attributed to $Ba_4$CuP $t_2$ $O_{8}$ compounds formed during the partial melting, which were considered als nucleation sites of 211 particles, rather than Pt inself.han Pt inself.

• Molecular & Cellular Toxicology
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• 제2권4호
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• pp.229-235
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• 2006

Volatile organic compounds (VOCs) are a major component of urban air pollution. It is documented that low exposure levels of VOCs induce alterations in immune reactivity resulting in a subsequent higher risk for the development of allergic reactivity and asthma. Despite these facts, there are few reports on the affected primary target and the underlying effective causal mechanisms. So in this study, to better understand the risk of BTX (benzene, toluene and o-xylene) which are the major VOCs and to identify novel biomarkers on immune response to these VOCs exposure in human T lymphocytes, we performed the toxicogenomic study by analyzing of gene expression profiles using 35 k human oligo-microarray. BTX generated specific gene expression patterns in Jurkat cell line. By clustering analysis, we identified some genes as potential markers on immuno-modulating effects of BTX. Four genes of these, HLA-DOA, ITGB2, HMGA2 and 5TAT4 were the most significantly affected by BTX exposure. Thus, this study suggests that these differentially expressed immune genes may play an important role in the pathogenesis on BTX exposure and have significant potential as novel biomarkers of exposure, susceptibility and response to BTC.