• Korean Journal of Microbiology
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• v.50 no.4
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• pp.327-333
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• 2014

Two genes encoding the mannanase of Bacillus sp. YB-1401 and B. amyloliquefaciens YB-1402, which had been isolated at acidic pH as mannanase producers, were each cloned into Escherichia coli, and sequenced. Both mannanase genes consisted of 1,080 nucleotides, encoding polypeptides of 360 amino acid residues. The deduced amino acid sequences of the two mannanase genes differed by four amino acid residues different, and were highly homologous to those of mannanases belonging to the glycosyl hydrolase family 26. Comparison of two mannanases produced from recombinant E. coli indicated that His-tagged mannanase of YB-1402 (HtMAN1402) was more stable than that of YB-1401 at acidic pH and high temperature. In particular, HtMAN1402 retained more than 50% of its activity at pH 3.0 after 4 h of pre-incubation, suggesting the enzyme is a valuable candidate for use as a feed additive. In addition, thermostability of the two mannanases was found to be enhanced by $Ca^{2+}$ ions.

• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.818-823
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• 1992

2-Ethylhexanoate compounds which contained Y, Er, Yb, Ba, and Cu were prepared separately. These metallo-organic compounds were dissolved together in the common solvent and the solution was homogeneous. From these solution, high $T_c$ superconductors $YBa_2Cu_3O_{7-\delta}(Y_{123})$, $ErBa_2Cu_3O_{7-\delta}(Er_{123})$, and $YbBa_2Cu_3O_{7-\delta}(Yb_{123})$ were prepared. XRD analysis showed that these superconductors were not single phase and contained some impurity phases including $YBa_2Cu_4O_8(Y_{124})$. This was also confirmed from the magnetic susceptibility measurement. Generally, critical temperatures were higher than that of the superconductors prepared by ceramic method. Volume diamagnetic susceptibility showed little variation compared to the specimen made by ceramic method.

• Korean Architects
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• s.618
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• pp.52-57
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• 2020

• Journal of the Korean Ceramic Society
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• v.41 no.2
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• pp.170-175
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• 2004

The ferroelectric (Y $b_{x}$ $Y_{1-x}$)Mn $O_3$ thin films were fabricated by sol-gel method using Y-acetate, Yb-acetate, and Mn-acetate as raw materials. The stable (Y $b_{x}$ $Y_{1-x}$)Mn $O_3$ precursor solution (sol) was prepared through the reflux process with acetylaceton as a catalyst and coated on Si(100) substrate by spin coating. The heat treatment temperature and, Rw ($H_2O$/alkoxide moi ratio) dependence on crystallinity of thin films were studied. The lowest temperature for obtaining YbMn $O_3$phase and the optimum heat-treatment conditions were proved as at 7$50^{\circ}C$ and 80$0^{\circ}C$, respectively. The hexagonal YbMn $O_3$with c-axis preferred orientation could be obtained at Rw=1 condition. The remanent polarization for the thin films of x=0 or 1 was about 200 nC/㎤ while, for the specimens ot 0< x< 1, were 50∼100 nC/$\textrm{cm}^2$.

• Journal of the Korean Chemical Society
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• v.34 no.3
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• pp.280-287
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• 1990

The electrochemical behavir of trivalent lanthanides [Sm(Ⅲ), Tb(Ⅲ), and Yb(Ⅲ)) complexes were investigated by the use of direct current, differential pulse polarography and cyclic voltammetry in aprotic media. These reduction peak were irreversible one-electron processes at $E_{pc}$ = -0.16 V, -0.35 V, -0.14 V, and -0.03 V of trivalent lanthanide complexes vs. Ag/AgCl electrode and the behavior of heavier lanthanides were decreased Sm > Tb > Ho > Yb order of the stability constant with decreasing atomic number.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.189-189
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• 2009

다양한 증착 조건에서 마그네트론 2원 동시 방전법을 이용하여 유리기판위에 ITO (10wt% $SnO_2$ 타겟과 $Yb_{2}O_{3}$ 타겟을 사용하여 증착한 ITO:Yb 박막의 구조적, 전기적 특성을 연구하였다. 스퍼터 가스로서는 Ar 가스를 사용하였고, RF power가 0W이고 어닐링온도가 $200^{\circ}C$일 때, 가장 낮은 비저항 $2.442{\times}10^{-4}{\Omega}cm$을 나타내었다. ITO:Yb 박막의 전기적 특성은 Hall 효과 측정장비, 박막의 결정구조는 X-선 회절(XRD), 광학적 특성은 UV 측정장비를 사용하여 측정하였다.

• Proceedings of the Materials Research Society of Korea Conference
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• 1997.10a
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• pp.140-140
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• 1997

• Proceedings of the Materials Research Society of Korea Conference
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• 2001.11a
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• pp.137-137
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• 2001

• Proceedings of the Materials Research Society of Korea Conference
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• 1996.11a
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• pp.67-67
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• 1996

• Microbiology and Biotechnology Letters
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• v.43 no.3
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• pp.195-203
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• 2015

Two bacterial strains, Bacillus licheniformis YB-1413 and YB-1414, producing extracellular α-galactosidase, were obtained from homemade Doenjang. On the basis of their biochemical properties, 16S rRNA sequences and random amplified polymorphic DNA patterns by polymerase chain reaction, they were found to be somewhat different from one another. α-Galactosidase productivities of the two isolates were increased by wheat bran, but drastically decreased by melibiose, raffinose and sucrose which were used as carbon sources. The enzyme productivities were increased by yeast extract as a nitrogen source with maximum levels of 1.87 U/ml for YB-1413 and 1.69 U/ml for YB-1414, respectively. The enzymes of both isolates exhibited maximum activity for hydrolysis of para-nitrophenyl-α-D-galactopyranoside (pNP-αGal) under reaction conditions of pH 6.0 and 45℃. Their hydrolyzing activities for pNP-αGal were drastically decreased by the addition of low concentrations of ribose and galactose. They were capable of hydrolyzing completely α-1,6 linked galactosyl residue in melibiose, raffinose and stachyose, which are known to be anti-nutritional factors in products of soybean and legume. In relation to the latter, the isolates YB-1413 and YB-1414 have potential applicability in improving soybean-fermented foods and the nutritional value of soybean feed.