• Journal of Microbiology and Biotechnology
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• 제14권2호
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• pp.415-416
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• 2004

Crystals of six new Bacillus thuringiensis serovarieties [coreanensis (H25), konkukian (H34), leesis (H33), seoulensis (H35), sooncheon (H41), and yosoo (HI8a18c)] with different H-antigens, which are toxic to Bombyx mori and/or mosquito larvae, were serologically quite distinct from each other.

• Bulletin of the Korean Chemical Society
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• 제19권6호
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• pp.676-680
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• 1998

The relaxation process of photogenerated carriers was investigated using conductivity measurement on ZnO under He, $H_2,\; CO_2\; and\; O_2$. The process was well explained with the rate constant of reaction or recombination of hole and electron, $k_h \;and\; k_e ( k_h > k_e)$, respectively. Generally, $k_h$ increased with the pressure of the gases. The slope of $k_h$ with respect to the pressure increased in the order of $H_2{\le}He, while $k_h$ of $O_2$ was sensitive to the history of the sample. The relaxation process on ZnO which was exposed to oxygen at 298 K and 573 K was observed during the illumination at 298 K and it was found that the rate constant of hole decreased with illumination time. From the result, it was suggested that the rate constant of photogenerated excess carriers was affected by the surface barrier of the semiconductor.

• ALGAE
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• 제17권1호
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• pp.21-31
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• 2002

Five species of Hypoglossum from the coasts of Korea were described. They were distinguished each other by vegetative morphology as well as reproductive structures. H. barbatum Okamura and H. simulans Wynne, Price et Ballantine were similar in their subalternate branchings but they were clearly different by developmental mode of 3rd-order cell rows. H. simulans is distinguished from H. barbatum as well as from the other three species in that only innermost cells of 2nd-order rows cut off 3rd-order cell rows. H. geminatum Okamura and H. caloglossoides Wynne et Kraft are oppositely branched but the latter is characterized by regular constrictions at branching points. H. minimum Yamada developed simple blades. Among them, H. simulans, H. caloglossoides, and H. minimum are newly recorded from Korean waters.

• Bulletin of the Korean Chemical Society
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• 제34권10호
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• pp.3065-3072
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• 2013

Direct synthesis of $H_2O_2$ and in situ oxidative desulfurization of model fuel over Au/Ti-HMS and Au/TS-1 catalysts has been comparatively investigated in water or methanol. Maximum amount (82%) of active $Au^0$ species for $H_2O_2$ synthesis was obtained. Au/Ti-HMS and Au/TS-1 exhibited the contrary performances in $H_2O_2$ synthesis as $CH_3OH/H_2O$ ratio of solvent changed. $H_2O_2$ decomposition and hydrogenation in water was inhibited by the introduction of methanol. Effect of $O_2/H_2$ ratio on $H_2O_2$ concentration, $H_2$ conversion and $H_2O_2$ selectivity revealed a relationship between $H_2O_2$ generation and $H_2$ consumption. The highest dibenzothiophene removal rate (83.2%) was obtained over Au/Ti-HMS in methanol at 1.5 of $O_2/H_2$ ratio and $60^{\circ}C$. But removal of thiophene over Au/TS-1 should be performed in water without heating to obtain a high removal rate (61.3%). Meanwhile, $H_2$ conversion and oxidative desulfurization selectivity of $H_2$ were presented.

• Animal cells and systems
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• 제3권3호
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• pp.295-301
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• 1999

The nucleotide sequence of a 447 base pair fragment in the mitochondrial cytochrome b gene and the complete sequence of the mitochondrial 12S ribosomal RNA gene, 938 bp, were analyzed to infer inter- and intraspecific genetic relationships of Hyla japonica and H. suweonensis from Korea and H, japonica from Japan. In the mitochondrial cytochrome b gene, genetic differentiation among H. japonica populations were 9.62% and 15.66% between H. japonica and H. suweonensis. Based on the Tamura-Nei distance, the level of sequence divergence ranged from 0.45% to 2.75% within Korean H. japonica, while 8.31%-8.87% between Korean and Japanese H. japonica and 11.51%-12.46% between H. japonica and H. suweonensis. In the neigh-bor-joining tree, Korean populations of H. japonica were clustered first at 2.22% and followed by Japanese H. japonica and H. suweonensis at 8.51% and 12.29%, respectively. In mitochondrial 12S rRNA gene, genetic differentiation between H. japonica and H. suweonensis nras 7.17% (68 bp) including 7 gaps. Based on Tamura-Nei distance, the level of sequence divergence ranged 3.53% between Korean and Japanese H. japonica and from 4.93% to 5.41% between H. japonica and H. suweonensis. Phenogram pattern of the 12S rRNA gene sequence corresponded with that of the mitochondrial cytochrome b gene.

• Journal of Microbiology and Biotechnology
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• 제23권2호
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• pp.149-155
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• 2013

Heterologous expression of a putative $K^+/H^+$ antiporter of Streptomyces coelicolor A3(2) (designated as sha4) in E. coli and Streptomyces hygroscopicus JCM4427 showed enhanced tolerance to $K^+$ stress, acidic-pH shock, and/or geldanamycin production under $K^+$ stress. In a series of $K^+$ extrusion experiments with sha4-carrying E. coli deficient in the $K^+/H^+$ antiporter, a restoration of impaired $K^+$ extrusion activity was observed. Based on this, it was concluded that sha4 was a true $K^+/H^+$ antiporter. In different sets of experiments, the sha4-carrying E. coli showed significantly improved tolerances to $K^+$ stresses and acidic-pH shock, whereas sha4-carrying S. hygroscopicus showed an improvement in $K^+$ stress tolerance only. The sha4-carrying S. hygroscopicus showed much higher geldanamycin productivity than the control under $K^+$ stress condition. In another set of experiments with a production medium, the secretion of geldanamycin was also significantly enhanced by the expression of sha4.

• 전기화학회지
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• 제9권2호
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• pp.77-83
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• 2006

Anodic overpotential has been investigated with gas composition changes in a $100cm^2$ class molten carbonate fuel cell. The overpotential was measured with steady state polarization, reactant gas addition (RA), inert gas step addition (ISA), and electrochemical impedance spectroscopy (EIS) methods at different anodic inlet gas compositions, i.e., $H_2:CO_2:H_2O=0.69:0.17:0.14\;atm\;and\;H_2:CO_2:H_2O=0.33:0.33:0.33\;atm$, at a fixed $H_2$ flow rate. The results demonstrate that the anodic overpotential decreases with increasing $CO_2\;and\;H_2O$ flow rates, indicating the anode reaction is a gas-phase mass-transfer control process of the reactant species, $H_2,\;CO_2,\;and\;H_2O$. It was also found that the mass-transfer resistance due to the $H_2$ species slightly increases at higher $CO_2\;and\;H_2O$ flow rates. EIS showed reduction of the lower frequency semi-circle with increasing $H_2O\;and\;CO_2$ flow rate without affecting the high frequency semi-circle.

• International Journal of Control, Automation, and Systems
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• 제1권2호
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• pp.206-209
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• 2003

An $H_2$/$H_{\infty}$ -controller realization is carried out by considering an entropy integral. Using J-spectral factorization, the parametrizations of all $H_{\infty}$ stabilizing controllers are derived. By the relation of a mixed $H_2$/$H_{\infty}$ control problem and a minimum entropy/$H_{\infty}$ control problem, the mixed $H_2$/$H_{\infty}$-controller state-space realization is presented.

• Korean Journal of Mathematics
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• 제10권2호
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• pp.141-148
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• 2002

We introduce the concept of gradation of supraopenness. With the concept of gradation of supraopenness, we invesigate the basic properties of H-fuzzy supratopological spaces, H-fuzzy suprainterior and H-fuzzy supraclosure.

• 호남수학학술지
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• 제38권3호
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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.