• Journal of the Korean Society of Combustion
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• v.21 no.3
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• pp.16-23
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• 2016

In this study, skeletal mechanisms are produced by directed relation graph with specified threshold value and sensitivity analysis based on species database from the directed relation graph. Skeletal mechanism is optimized through the elimination of unimportant reaction steps by computational singular perturbation importance index. Reduction is performed for the detailed mechanism of methyl butanoate consisting of 264 species and 1219 elementary reactions. Validation shows acceptable agreement for auto-ignition delays in wide parametric ranges of pressure, temperature and equivalence ratio. Methyl butanoate has been proposed as a simple biodiesel surrogate although the alkyl chain consists of four carbon atoms. The resulting surrogate mechanism for n-heptane and MB consists of 76 species and 226 reaction steps including those for NOx.

• Journal of Food Hygiene and Safety
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• v.12 no.3
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• pp.195-199
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• 1997

For the purpose of isolation and screening of tyrosinase inhibitory activity from edible mushrooms, Pleurotus ostreatus, Auricularia auricula-Judae, Umbilicaria esculenta, Agaricus bisporus, Flammuline velutipes, Lentinus edodes, Ganoderma lucidum, and Coriouls versicolor were examined by tracing inhibitory activities against tyrosinase, utilizing L-3,4-dihydroxyphenylalanine (L-DOPA) as a substrate. Among the eight edible mushrooms tested, Umbilicaria esculenta showed potent enzyme inhibitory activities above 7804% against tyrosinase in ethylacetate (EtOAc) extracts. Ganoderma lucidum and Agaricus bisporus showed inhibitory activities of 67.3% and 51.5% in water extracts. EtOAc extracts of Umbilicaria esculenta was fractionated from silicagel column chromatography and one fraction showed the most inhibitory activity of 60.9%. The three bands (Rf=0.38, 0.27, 0.19) were isolated from preparative TLC of the fraction for purification and identified as mixtures of orsellinate, methyl orsellinate, methyl lecanorate, and methyl gyrophorate by high pressure liquid chromatography (HPLC), ultravisible spectrophotometer (UV), mass spectrophotometer (Mass), nuclear magnetic resonance spectrometer (NMR).

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.863-866
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• 2009

Ethanol/3-methyl-1-butanol 계에 대하여 정온하 즉 50, 55, 60, 65, 70, 75 및 $80^{\circ}C$에서 2성분 기-액 평형측정치를 측정하였다. 측정된 기-액평형치의 액조성과 비휘발도의 대수치와의 관계를 직교좌표에 plot하면 직선이 이루어지고 온도변화에 대한 각각의 직선이 평형임을 확인하였다. Ethanol/3-methyl-1-butanol 계에 대한 추산식은 각각의 온도변화에 따라 나타내었고 이식들을 이용하여 추산식을 구하였다. 추산식으로부터 구한 추산치와 측정치를 비교 검토한 결과 Ethanol/3-methyl-1-butanol 계에서는 기상조성의 몰분율은 ${\pm}0.00051$[-]의 오차 범위에서 잘 일치하는 것으로 나타났고, modified UNIFAC방법은 실측치와 비교한 평균오차는 ${\pm}0.0022$[-]에서 추산하였다. 따라서 본 연구에서 제안한 추산법이 2성분계 기-액평형치를 추산하는 방법으로 타당함을 확인하였다.

• Korean Journal of Environmental Agriculture
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• v.16 no.3
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• pp.269-273
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• 1997

This research aims at developing a new plant growth inhibitors related to abscisic acid by means of esterification of (S)-(+)-ABA with p-hydroxy methyl cinnamate and umbelliferone, and testing its biological activity on growth of rice seedlings. The over-all yield of ABA-methyl cinnamate(AC) and ABA-umbelliferone(AC) ester compounds were 83% and 78%, respectively. The growth inhibition activity of these synthetic compounds were shown about 3 to 10 times(AC) and 10 to 30 times(AU) higher than (S)-(+)-ABA.

• Journal of the Korea Safety Management & Science
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• v.1 no.1
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• pp.259-272
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• 1999

In order to enhance the selectivity, productivity and yield of methyl fructoside, which was synthesized by enzymatic glycosylation of sucrose and methanol solution, controlling of surface property of solid support using different immobilization procedures optimized microenvironment of immobilized invertase. Silanization and polyethylene imine coating methods were adopted to give a hydrophobic and hydrophilic environment of immobilized invertase. As a result, polyethyleneimine coating method gave higher loading of enzyme, effective activity, and relative activity than silanization method, because it brought on increasing the functional density of amino group and enhancing the conservation of activity by regulating of hydrophilicity. And then, hydrophilic environment was possible to restraint the assessing of methyl fructoside molecule, which was more hydrophobic than sucrose, fructose, and glucose molecule in the reaction mixture, into .the active site of immobilizedinvertase. Consequently, hydrophilic microenvironment of immobilized invertase by polyethyleneimine coating obtained higher yield and productivity with increasing conversion than silanized and native invertase. Thus, this procedure optimized the microenvironment of immobilized invertase suitable for the enzymatic synthesis of methyl fructoside.

• YAKHAK HOEJI
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• v.40 no.1
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• pp.19-24
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• 1996

The 6,7-dichloroquinolone-5,8-dione(I) was reacted with ethyl acetoacetate in the presence of sodium ethoxide to yield 6-(${\alpha}$-acetyl-${\alpha$-ethoxycarbonyl-methyl)-7-chloro-quin oline-5,8-dione(II). When this compound II was reacted with some alkylamine (methylamine, ethylamine, propylamine, isopropylamine, cyclopropylamine, methoxyethylamine, ethanolamine, benzylamine, furfurylamine), 1N-alkyl-2-methyl-3-ethoxycarbonyl-pyridino(2,3f)-indole-4,9-dione(IIIa-i) were obtained via intramolecular cyclization.

• Elastomers and Composites
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• v.47 no.3
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• pp.223-230
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• 2012

The rheological parameters of poly(methyl acrylate)-poly(acrylonitrile) copolymers were obtained by applying the experimental stress relaxation curves to the theoretical equation of the Eyring-Halsey non-Newtonian model. The experimentals of stress relaxation were carried out using the tensile tester with the solvent chamber. The determination of rheological parameters was performed from computer calculation. It was observed that the rheological parameters of these copolymer samples are directly related to the self diffusions and viscosities and activation energies of flow segments.

• YAKHAK HOEJI
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• v.31 no.4
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• pp.219-223
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• 1987

2-Cyclohexylimino-3-cyclohexyl-5-methyl-4-oxo-2H, 5H-1, 3-oxazino [5,6-C]-1, 2-benzothiazine-6,6-dioxide 2 was hydrolized in d-HCl/$CH_3$CN to give 5-methyl-3-cyclohexyl-2H, 5H-1, 3-oxazino [5, 6-C]-1, 2-benzothiazine-2, 4(3H)-dione 6, 6-dioxide 3 in 82% yield. The alkaline hydrolysis of 3 afforded to 4-hydroxy-2-methyl-N-(cyclohexyl)-2H-1, 2-benzothiazine-3-carboxamide-1, 1-dioxide 4 in 88% yield. On the other hand 3 was synthesized from 4 and ethylchloroformate on the reversed procedure.

• Proceedings of the KAIS Fall Conference
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• 2004.11a
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• pp.265-268
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• 2004

Methyl methacrlate와 cyclopentadiene을 반응하여 Methyl 5-methylbicyclo(2.2.1)hept-2-ene-5-carboxylate(MMBHC)를 합성코자 하였다. 합성된 MMBHC의 온도, solvent 변화와 촉매($AlCl_3$)의 사용 유무에 따른 endo, exe의 비율을 관찰하였다. 온도가 낮은 경우 온도가 높은 쪽 보다 endo 비율이 높았고 촉매($AlCl_3$)를 사용하였을 때(약 endo : exo = 63 : 37) 촉매를 사용하지 않은 반응(endo : exe = 34 : 66)보다 endo의 비율이 높았다. methyl acrylate를 사용한 경우 같은 조건에서 endo : exe의 비율이 93.5 : 6.5로 MMA를 사용한 경우보다 endo의 비율은 좋았다. 온도가 높은 경우 수율은 좋았지만 exe의 비율이 높았고 solvent에 따라 endo, exe의 선택도는 큰 차이를 보이지 않음을 알 수 있었다.

• Bulletin of the Korean Chemical Society
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• v.8 no.2
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• pp.73-79
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• 1987

In this work we have investigated temperature dependence of spin-rotational relaxation rate, $(1/T_1)_{SR}$, of methyl carbon-13's in 2-bromo-p-xylene, 2,5-dimethylaniline, and 2,5-dimethylanisole and have found that temperature behaviors of two methyl carbon-13's in ortho- and meta-position, respectively, are substantially different. It has been confirmed that the modified Burke-Chan model proposed by Park et al. can nicely explain different temperature dependence of $(1/T_1)_{SR}$ for these two methyl carbon-13's while the original Burke-Chan model fails to do so.