• Fibers and Polymers
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• 제5권4호
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• pp.303-308
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• 2004

A natural colorant was extracted from Cassia tara L. using buffer solutions (pH: 2-11) as extractants. The dyeing solution (Cassia tara L. extract) extracted using pH 9 buffer solution was found to give the highest K/S values of dyed fabrics. Cotton and silk fabrics were dyed with Cassia tara L. extract at $60^{\circ}C$ for 60 min with pre-treatment of various metal salts as mordants. It was found that Cassia tara L. extract was polygenetic dyestuffs and its major components were anthraquinones. Studies have been made on the effects of the kind of mordant on dyeing properties and colour fastnesses of cotton and silk fabrics. The K/S of cotton fabrics increased in the order of the dyeing using $FeSO_4 >CuSO_4> ZnSO_4> MnSO_4\cong Al_2(SO_4)_3 > NiSo_4 > none$, however, the K/S of silk fabrics increased in the order of the dyeing using $FeSO_4 > CuSO_4 > ZnSO_4\cong Al_2(SO_4)_3 > MnSO_4\cong NiSO_4 > none$. It was found that the K/S values of dyed fabrics were largely affected by the colour difference $(\DeltaE)$ between mordanted fabric and control fabric. However, they were not depended on the content of mordanted metal ion of the fabrics. Mordants $FeSO_4$ and CuSO_4$ for cotton fabric, $FeSO_4,\; CuSO_4,\; and\; Al_2(S0_4)_3$ for silk fabric were found to give good light fastness (rating 4).

• Elastomers and Composites
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• 제44권3호
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• pp.329-335
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• 2009

4종류의 새로운 형태의 열방성 액정폴리우레탄을 4,4'-Bis(5-hydroxypentoxy)biphenyl (BP5)와 2,6-tolylene diisocyanate (2,6-TDI), 2,5-tolylene diisocyanate (2,5-TDI), 및 2,4-tolylene diisocyanate (2,4-TDI), 1,4-phenylene diisocyanate (1,4-PDI) 의 중부가 반응에 의해 합성하였다. 단량체 BP5은 스멕틱상을 형성하였으며 1,4-PDI/BP5을 제외한 나머지 폴리우레탄에서는 모두 액정성을 나타내었다. 생성된 폴리우레탄의 구조는 FT-IR과 ^1H$ NMR 스펙트럼으로 확인하였고 열적 성질은 DSC와 편광현미경으로 관찰하였다.

• 약학회지
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• 제41권6호
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• pp.692-697
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• 1997

Creatine and 3,4-Dimethylhippuric acid (3,4-DMHA), a glycine conjugate of 1,2,4-trimethyl-benzene (1,2,4-TMB) were determined in the urine of workers exposed to 1,2,4-TMB vapor. The best condition for the simultaneous determination of 3,4-DMHA and creatine by high performance liquid chromatography was obtained by reverse phase $C_{18}$ column (4.6${\times}$150mm, 5${\mu}m$) as stationary phase and 20% acetonitrile in 20mM phosphate buffer (pH 3.0) containing 4mM sodium octylsulfate(SOS)as mobile phase. The recovery of 3,4-DMHA spiked to blank urine in the range of 1~5${\mu}g$/ml was about 96%. The concentration of urinary 3,4-DMHA of workers had a positive correlation with the environmental level of 1,2,4-TMB (r=0.866). The data suggest that urinary 3,4-DMHA concentration is a useful biological index for 1,2,4-TMB exposure.

• 대한화학회지
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• 제55권4호
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• pp.656-661
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• 2011

5-(3,4,5-Triethoxyphenyl)-1,3,4-oxadiazole-2-thiol 6을 3-(bromomethyl)-2-chloroquinoline or 2-(p-tolyloxy)-3-(bromomethyl) quinoline 4a-j 화합물과 반응시켜서 3-((5-(3,4,5-triethoxyphenyl)-1,3,4-oxadiazol-2-ylthio)methyl)-2-chloroquinoline 또는 3-((5-(3,4,5-triethoxyphenyl)-1,3,4-oxadiazol-2-ylthio)methyl)-2-(p-tolyloxy)quinoline 7a-j를 합성하였다. 합성한 화합물들에 대한 항균활성을 측정하였으며, 화합물 7d, 7i 및 7j 은 우수한 활성을 나타내었다.

• 한국자기학회지
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• 제18권2호
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• pp.75-78
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• 2008

$AB_2X_4$((A, B)=Transition Metal, X=O, S, Se) 물질에서의 8면체 자리의 이온 거동과 4면체 자리 이온과의 상호작용에 대하여 많은 연구가 이루어지고 있다. 본 연구에서는 4면체 자리에 비자성 이온인 Zn 이온을 치환함에 따른 자기구조의 변화를 관측하여 8면체 자리의 자기구조를 분석하고자 하였다. Cr이온의 일부를 Fe로 치환한 $[Co_{0.9}Zn_{0.1}]_A[Cr_{1.98}{^{57}Fe_{0.02}}]_BO_4$의 닐온도($T_N$는 90K로 $CoCr_{1.98}{^{57}Fe_{0.02}}O_4$ 비하여 감소하였다. 4.2 K에서의 초미세자기장값의 분석결과, 초미세자기장값의 작은 차이를 보이는 잘 분리된 2-set 형태로 나타났으며, $CoCr_{1.98}{^{57}Fe_{0.02}}O_4$의 초미세자기장값은 488, 478 kOe 인데 반하여, $Co_{0.9}Zn_{0.1}Cr_{1.98}{^{57}Fe_{0.02}}O_4$의 초미세자기장값은 $B_1=486$, $B_2=468$ kOe으로 나타났다. Zn 이온의 치환에 따라서 초미세자기장값의 변화를 알 수 있었다. 이러한 결과로 인하여, Zn 이온이 x=0.1 치환된 물질의 경우, 스핀재정렬온도($T_S$)가 18K으로 감소함을 알 수 있다.

• 한국재료학회지
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• 제22권9호
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• pp.489-493
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• 2012

Green phosphors $K_2BaW_2O_8:Tb^{3+}$(1.0 mol%) were synthesized by solid state reaction method. Differential thermal analysis was applied to trace the reaction processes. Three endothermic values of 95, 706, and $1055^{\circ}C$ correspond to the loss of absorbed water, the release of carbon dioxide, and the beginning of the melting point, respectively. The phase purity of the powders was examined using powder X-ray diffraction(XRD). Two strong excitation bands in the wavelength region of 200-310 nm were found to be due to the ${WO_4}^{2-}$ exciton transition and the 4f-5d transition of $Tb^{3+}$ in $K_2BaW_2O_8$. The excitation spectrum presents several lines in the range of 310-380 nm; these are assigned to the 4f-4f transitions of the $Tb^{3+}$ ion. The strong emission line at around 550 nm, due to the $^5D_4{\rightarrow}^7F_5$ transition, is observed together with weak lines of the $^5D_4{\rightarrow}^7F_J$(J = 3, 4, and 6) transitions. A broad emission band peaking at 530 nm is observed at 10 K, while it disappears at room temperature. The decay times of $Tb^{3+}$ $^5D_4{\rightarrow}^7F_5$ emission are estimated to be 4.8 and 1.4 ms, respectively, at 10 and 295 K; those of the ${WO_4}^{2-}$ exciton emissions are 22 and 0.92 ${\mu}s$ at 10 and 200 K, respectively.

• Bulletin of the Korean Chemical Society
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• 제31권1호
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• pp.31-34
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• 2010

Noble N-substituted-3-fluoropyrroles derivatives were prepared from new precursor via ring formation. The addition reaction of ethyl iododifluoroacetate to vinyl trimethylsilane under the Cu(0) catalyst resulted in the formation of ethyl-2,2-difluoro-4-iodo-4-(trimethylsilyl)butanolate, which reacted with diisobutylaluminium hydride at $-30^{\circ}C$ to yield 2,2-diflouro-4-iodo-4-(trimethylsilyl)butanal. Finally, a series of N-substituted-3-fluoropyrrole derivatives were synthesized by the reaction of 2,2-diflouro-4-iodo-4-(trimethylsilyl)butanal with $NH_4OH$ or primary amines followed by reaction with KF solution.

• 약학회지
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• 제35권6호
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• pp.515-521
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• 1991

A number of 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(4-substitutedcarbamyl-1-piperazinyl) quinoline [or 1,8-naphthyridine]-3-carboxylic acid and their pivaloyloxymethyl esters were prepared. The compounds synthesized were evaluated for antibacterial activity in vitro against Escherichia coli, Bacillus subtilis, Proteus vulgaris, Klebsiella pneumoniae, Staphylococcus aureus and Pseudomonas aeruginosa. Among those 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(4-methylcarbamyl-1-piperazinyl) quinoline-3-carboxylic acid [1] and 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(4-methylcarbamyl-1-piperazinyl)1,8-naphthyridine-3-carboxylic acid [6] showed the most potent in vitro antibacterial activity.

• Archives of Pharmacal Research
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• 제17권6호
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• pp.420-423
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• 1994

Various N'-substituted anilino-N-methyl-N'-nitrosoureas(2a-n) were easily prepared from the reaction of substituted phenylhydraines $(3, 4-CH_3, {\;} 3-, {\;} 4-OCH_3, {\;} 3-, {\;} 4-F, {\;} 3, {\;} 4-Cl, {\;} 4-Br, {\;} 2-, {\;} 3-, {\;} 4-NO_2, 4-(NO_2)_2)$ with methyl isocyanate, followed by the nitrosation with 99% HCOOH and dry sodium lnitrite powder. Surprisingly, of these series of analogus, the anilino-nitrocosureas substituted with eletron-withdrawing nitro groups (2k-a) showed significantly low $ED_{30}$ values of $1.4-3.4 {\mu}g/ml.$ In addition, none of these copounds subtituted with electron-donating groups exhibited cytotoxicities.

• Bulletin of the Korean Chemical Society
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• 제35권4호
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• pp.1182-1190
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• 2014

$Cd_{1-x}Zn_xS$-sensitized $K_4Nb_6O_{17}$ composite photocatalysts (designated $Cd_{1-x}Zn_xS/K_4Nb_6O_{17}$) were prepared via a simple deposition-precipitation method. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDS), $N_2$ sorption, ultraviolet-visible light diffuse reflectance spectroscopy (UV-Vis DRS), photoluminescence measurements (PL), and X-ray photoelectron spectroscopy (XPS). The $Cd_{0.8}Zn_{0.2}S$ particles were scattered on the surface of $K_4Nb_6O_{17}$, and had a relatively uniform size distribution around 50 nm. The absorption edge of $K_4Nb_6O_{17}$ was shifted to the visible light region and the recombination of photo-generated electrons and holes suppressed after $Cd_{0.8}Zn_{0.2}S$ loading. The $Cd_{0.8}Zn_{0.2}S$(25 wt %)/$K_4Nb_6O_{17}$ composite possessed the highest photocatalytic activity for hydrogen production under visible light irradiation, evolving 8.278 mmol/g in 3 h. Recyclability tests were performed, and the composite photocatalysts were found to be fairly stable. The mechanism of charge separation between the photogenerated electrons and holes at the $Cd_{0.8}Zn_{0.2}S/K_4Nb_6O_{17}$ composite was discussed.