• Journal of the Korean Chemical Society
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• v.30 no.6
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• pp.495-499
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• 1986

Structures of 4H-pyran-4-one(I), 4H-pyran-4-thione(II), 4H-thiapyran-4-one (III), 4H-thiapyran-4-thione(IV) have been determined by MNDO and MINDO/3 methods. Geometries and physicochemical properties, especially the aromaticity, were found to agree well with the results of microwave experiments. The order of aromaticity was found to be (IV) > (III) > (II) > (I), which demonstrated inhibitory effect of strongly electronegative oxygen atom on the electron delocaligation, and the order of dipole moment, (II) > (IV) > (I) > (III), indicated the dominant contribution of the bond length of carbonyl group (C=O or C=S)

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.387-390
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• 2006

We report here that under strong attacksof external $CH_4$ guest molecules the sII and sH methane hydrates are structurally transformed to the crystalline me framework of sI, leading to favorable change of the lattice dimension of the host-guest networks. The High Power Decoupling $^{13}C$ NMR and Raman spectroscopies were used to identify structure transitions of the mixed $CH_4+C_2H_6$ hydrates (sIIl) and hydrocarbons (methylcyclohexane, isopentane) + $CH_4$ hydrates (sH). The resulting spectra indicate that most of the synthesized sII and sH hydrates were transformed to methane hydrate of sl under 110 bar and particularly the coexistence of sl with sII or sH appear according to the surrounding methane-rich gas conditions. The present findings might be expected to Provide rational evidences regarding the preponderant occurrence of naturally-occurring sI methane hydrates in marine sediments.

• Honam Mathematical Journal
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• v.38 no.3
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• pp.593-611
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• 2016

This paper is concerned with the classifications of quadric surfaces of first and second kinds in Euclidean 3-space satisfying the Jacobi condition with respect to their curvatures, the Gaussian curvature K, the mean curvature H, second mean curvature $H_{II}$ and second Gaussian curvature $K_{II}$. Also, we study the zero and non-zero constant curvatures of these surfaces. Furthermore, we investigated the (A, B)-Weingarten, (A, B)-linear Weingarten as well as some special ($C^2$, K) and $(C^2,\;K{\sqrt{K}})$-nonlinear Weingarten quadric surfaces in $E^3$, where $A{\neq}B$, A, $B{\in}{K,H,H_{II},K_{II}}$ and $C{\in}{H,H_{II},K_{II}}$. Finally, some important new lemmas are presented.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.154-165
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• 1996

As II-anhydrite reacts with C3A(aluminate), C4AF(ferrite) at initial hydration of cement and assists the hydrolysis of C3S(calcium silicate), the production rate of ettringite(3C3A.3CaSO4.32H2O) and C-S-H gel was acclerated. It was known that compressive strength of cement concrete improved due to the effect of II-anhydrite. For the checking these effects of II-anhydrite, the fluidity and compressive strength of cementmortar admixed with II-anhydrite and pozollanic fine powders were investigated. By means of SEM analysis, the surface structure of mortar with the condition of steam curing at curing days=28 was investigated. As a result of this experiment, it was examined that II-anhydrite had an increase on the fluidity of cementpaste and compressive strength of mortar.

• Korean Journal of Materials Research
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• v.5 no.6
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• pp.657-666
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• 1995

Chemical vapor deposition of copper from the Cu(hfac)$_2$, Cu(II) hexafluoroacetylacetonate precursor, has been thermodynamically investigated by the minimization of Gibbs free energy of the system. For the Cu(hfac)$_2$-Ar system, carbon incorporation into the deposited films was observed in all the process conditions, which is presumably inherent from the thermal decomposition of the Cu(hfac)$_2$, precursor. For the Cu(hfac)$_2$-H$_2$system, lower temperatures were required than those of the Cu(hfac)$_2$-Ar system for the depositon of the copper films. Furthermore, we identified that the appearances of the condensed phases were sequentially changed from the codeposits of C(s)+CuF(s) to C(s)+CuF(s)+Cu(s), C(s)+Cu(s), Cu(s), and C(s), when the H$_2$input ratio and th reaction temperature were increased.

• Korean Journal of Microbiology
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• v.30 no.4
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• pp.239-245
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• 1992

Buci1llr.s 11c~h~n~1rnSiSi.As 3-2MI which is responsible for the special taste of traditionalKorean soy sause produced two kinds of proteinase. The activity of the proteinasc I washigher about two fold than that of proteinase 11. The optimai, reaction pH of proteinaseI and I1 wcre found to be 7-1 1.5 and 7-9. respectively. Proteinase I1 was more stable andactive than proteinase I at pH ranges around 3 to 5. The optimal te~tlperature of proteinaseI and I1 were 502. The temperature stabilitl of proteinase I1 was Inore stable thanproteinase 1 at temperature range around 30-quot;~A. ctivities of proteinase I and I1 graduallydeclined above $30^{\circ}$C and 45C. respectively. Proteinasc 1 was more active than proteinaseI1 at salt concentration range around 25-3500. The K,,, values of casein and soy proteinfor proteinase I were 6.89 mglml and 3.98 mglml. In case of proteinase 11. they were 9.00mgiml anti 11.44 111g/ml. respectively. The activity of the crudc enzyme was increased by1 rnM Pb(CH3COO). but was decreased by 5 n1M and 10 rnM of HgS04 and ZnS04. Thetwo proteinases produced amino acids and peptides from the soybean protein. The peptideswere digested into amino acids. Both protcinases were found to be the main enzymes thatproduced amino acids which make the main taste of traditional Korean soy sauce.al Korean soy sauce.

• Mycobiology
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• v.35 no.3
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• pp.135-144
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• 2007

The removal efficiency of the heavy metals Zn, Pb and Cd by the zoosporic fungal species Saprolegnia delica and the terrestrial fungus Trichoderma viride, isolated from polluted water drainages in the Delta of Nile in Egypt, as affected by various ranges of pH values and different temperature degrees, was extensively investigated. The maximum removal efficiency of S. delica for Zn(II) and Cd(II) was obtained at pH 8 and for Pb(II) was at pH 6 whilst the removal efficiency of T. viride was found to be optimum at pH 6 for the three applied heavy metals. Regardless the median lethal doses of the three heavy metals, Zn recorded the highest bioaccumulation potency by S. delica at all pH values except at pH 4, followed by Pb whereas Cd showed the lowest removal potency by the fungal species and vice versa in case of T. viride. The optimum bio-mass dry weight production by S. delica was found when the fungus was grown in the medium treated with the heavy metal Pb at pH 6, followed by Zn at pH 8 and Cd at pH 8. The optimum biomass dry weight yield by T. viride amended with Zn, Pb and Cd was obtained at pH 6 for the three heavy metals with the maximum value at Zn. The highest yield of biomass dry weight was found when T. viride treated with Cd at all different pH values followed by Pb whilst Zn output was the lowest and this result was reversed in case of S. delica. The maximum removal efficiency and the biomass dry weight production for the three tested heavy metals was obtained at the incubation temperature $20^{\circ}C$ in case of S. delica while it was $25^{\circ}C$ for T. viride. Incubation of T. viride at higher temperatures ($30^{\circ}C\;and\;35^{\circ}C$) enhanced the removal efficiency of Pb and Cd than low temperatures ($15^{\circ}C\;and\;20^{\circ}C$) and vice versa in case of Zn removal. At all tested incubation temperatures, the maximum yield of biomass dry weight was attained at Zn treatment by the two tested fungal species. The bioaccumulation potency of S. delica for Zn was higher than that for Pb at all temperature degrees of incubation and Cd bioaccumulation was the lowest whereas T. viride showed the highest removal efficiency for Pb followed by Cd and Zn was the minor of the heavy metals.

• Proceedings of the PSK Conference
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• 2000.04a
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• pp.208.2-209
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• 2000

• Applied Biological Chemistry
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• v.40 no.1
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• pp.85-88
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• 1997

In orther to isolate antibacterial substances from the flower of Chrysanthemum zawadskii Herbich var. latilobum Kitam., the chloroform fraction was fractionated according to the activity against B. subtilis, S. aureus and V. parahaemolyticus. Two antibacterial substances were isolated and purified by preparative TLC and recrystallization. Compound I showed activity against all the tested bacteria and compound II exhibited the activity against B. subtilis and v. parahaemolyticus except S. aureus. Compared to benzoic acid and sorbic acid which are being used as food preservatives, compounds I and II showed about five-fold stronger antibacterial activity against B. subtilis and V. parahaemolyticus. On the basis of spectrometric studies including $^1H-NMR,\;^{13}C-NMR,\;DEPT,\;^1H-^1H\;COSY,\;^{13}C-^1H\;COSY$ and Mass, compounds I and II were identified as angeloylcumambrin B and cumambrin A, respectively. This is the first report of the isolation of angeloylcumambrin B and cumambrin A from this plant.

• Applied Biological Chemistry
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• v.46 no.3
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• pp.246-250
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• 2003

In order to isolate antibacterial substances from the rhizome of Zingiber mioga Roscoe, the ethanol extracts was fractionated according to the activity against Bacillus subtilis, B. cereus and Staphylococcus aureus. Three antibacterial substances were isolated and purified by column chromatography and recrystallization. Compounds I and III showed activity against all the tested bacterias and compound II exhibited the activity against B. subtilis and B. cereus S. aureus. Compound I was examined antimicrobial activity against B. subtilis, B. cereus and S. aureus by optical density using Bioscreen C. Compound I showed strong growth inhibition at 10 ppm on B. subtilis and B. cereus for 72 hrs, and at 25 ppm on S. aureus. On the basis of spectrometric studies including $1^H-NMR$, ${13}^C-NMR$, DEPT, IH-lH COSY, HMQC, HMBC and IR, compounds I, II and III were identified as $(E)-8{\beta}(17)-epoxylabd-12-ene-15,16-dial\;(C_{20}H_{30}O_3,\;MW=318)$, galanolactone $(C_{20}H_{30}O_3\;MW=318)$ and galanal A $(C_{20}H_{30}O_3,\;MW=318)$, respectively. These results are the first reports on the isolation of $(E)-8{\beta}(17)-epoxylabd-12-ene-15,16-dial, galanolactone and galanal A from the rhizome of Zingiber mioga.