• Microbiology and Biotechnology Letters
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• v.16 no.3
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• pp.193-198
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• 1988

Catalase from Aspergillus niger KUF-04 was purified by five steps including gel filtration. The overall purification gave 64-fold purified preparation, a yield of about nine percent. The enzyme showed its maximum absorption at 406 nm. The optimum pH and temperature for the enzyme activity were around pH 7.0 and 6$0^{\circ}C$, respectively. The catalase was found to be stable in the range of pH 4.0 to pH 8.3 and temperature 2$0^{\circ}C$ to 6$0^{\circ}C$. However, it lost nearly all of the activity by heating at 8$0^{\circ}C$ for 20 min. The activity was markedly inhibited by hydroxylamine, potassium cyanide and sodium azide.

• Applied Biological Chemistry
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• v.13 no.3
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• pp.223-229
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• 1970

1. The preparation and some enzymatic properties of crude alkaline protease from a thermophilic mold, Myriococcum sp. was investigated. 2. Optimum pH for the hydrolysis of casein was 9.0 at $50^{\circ}C$ for 10 minutes. Optimum temperature was $55^{\circ}C$ at pH 9.0 for 10 minutes. The enzyme was highly stable at the range of pH 6.0 to 11.0 at $30^{\circ}C$ 3. The alkaline protease in the culture filterate was isolated two fractions by elution column chromatography on DEAE-Cellulose.

• Journal of the Korean Ceramic Society
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• v.28 no.1
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• pp.67-73
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• 1991

Monodispersed PZT fine particles were obtained from the condition which 0.2Pb (OC3H7)2/EtOH, 0.108Zr(OC4H9)4/EtOH and 0.092 Ti (OC2H5)4/EtOH were refluxed for 5 hrs at 76$^{\circ}C$ and hydrolyzed with 0.1-0.4 H2O/EtOH. The monodispersed particle was amorphous and crystallized to the tetragonal PZT phase when heated at $600^{\circ}C$. Particle size was about 0.55${\mu}{\textrm}{m}$ in 0.3 H2O/EtOH and 0.3${\mu}{\textrm}{m}$ in other cases. Relative density of sintered body at 90$0^{\circ}C$ and 100$0^{\circ}C$ was 93.5% and 98%, respectively.

• Journal of Environmental Science International
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• v.11 no.10
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• pp.1103-1108
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• 2002

In order to evaluate the degradation organophosphorus pesticide, EPN, in water environment, the effects of water temp.(10$^{circ}C,\;30^{\circ}C$), pH(3-11) and sunlight on its degradation were investigated during 10 days. The degradation rate of EPN(200 rpm) was faster at higher water temp. and higher pH, i.e., its degradation rate at pH 3, 5, 7, 9, 11 was 57, 63, 66, 69, 75%(1$0^{\circ}C$), and 70, 74, 79, 91, 97%(3$0^{\circ}C$) after 10 days, respectively. The effect of water temp. on its degradation was little in acidic condition, but was rather great in alkaline condition, with time. EPN was degraded fast at the alkaline condition by photolysis. At the condition of pH 11, EPN was degraded fast at the early stage in the first 2 days, but after that the degradation rate was weakened.

• Journal of Magnetics
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• v.2 no.4
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• pp.126-129
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• 1997

We have studied magnetostructural phase transitions in the perovskite-type layered structure compound (C18H37NH3)2 MnCl4 by means of electron paramagnetic resonance (EPR) and superconducting quantum interference device (SQUID) measurements. Distinct slopes were observed in the linear temperature dependences of the Mn++ EPR linewidth in the low and high temperature phases. Besides, linewidth anomalies at the transition temperatures sensitively reflect the magnetic changes arising from the MnCl6 octahedra.

• Journal of the Korean Chemical Society
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• v.48 no.3
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• pp.327-330
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• 2004

• Journal of the Korean Wood Science and Technology
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• v.51 no.1
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• pp.38-48
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• 2023

Two important steps in utilizing technical kraft lignin (KL) from black liquor to synthesize lignin-phenol-formaldehyde (LPF) resin are its extraction via precipitation and fractionation. However, the effects of precipitation pH and acetone fractionation on the characteristics of hardwood KL have not been studied for LPF resins. Therefore, this paper reports the effects of the precipitation pH of black liquor and acetone fractionation on the characteristics of KL from mixed hardwood species for LPF resins. The precipitation was conducted at various pH levels from 3 to 9 of black liquor to obtain crude KL (C-KL), which was used in acetone fractionation to produce acetone-soluble KL (AS-KL) and acetone-insoluble KL (AI-KL). Precipitation at pH 3 and 9 produced the highest and lowest yields of C-KL, respectively. As expected, the C-KL infrared spectra were similar regardless of the precipitation pH levels. As the pH increased, the molecular weight of C-KL increased. However, the molecular weight of AS-KL and AI-KL after acetone fractionation increased to a maximum of 4,170 and 47,190 g/mol at pH 7, then decreased to 3,210 and 19,970 g/mol at pH 9, respectively. The smallest molecular weights of AS-KL and AI-KL were 3,210 and 15,480 g/mol and were found at pH 9 and 3, respectively. These results suggest that both AS-KL at pH 9 and AI-KL at pH 3 have good potential as starting lignins for synthesizing LPF resins that require cross-linking for polymerization.

• Journal of the Korean Ceramic Society
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• v.35 no.5
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• pp.479-485
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• 1998

Raw mateials such as limestone quartzite bauxite and anhydrite were used in the production of mod-ified beloite cement. Two kinds of clinker were synthesized with relatively higher content of $C_2S$ than that of $C_4A_3{\={S}}$ Concerning $C_2S$ the main mineral component borax ($Na_2O\;2B_2O_3\;10H_2O$) was added to stimu-late hydraulic reactivity and this would be possible by stabilizing ${\alpha}'-C_2S$ at room temperature. We had in-tended to compare burning and hydraulic characteristics of clinkers with one another by varying the amount of borax addition and to study the appropriate amount of anhydrite addition needed in the strengthening of cement during hydration. It was concluded that the effective amount of borax addition ne-eded for stabilization of ${\alpha}'-C_2S$ was 5 wt% in 60wt% $C_2S$ inclusive clinker and adding anhydrite in the ra-tio of 1.3 of $SO_3/Al_3O_3$ was appropriate in the production of cement by this clinker. Only ettringite was seen to contribute to the strength without additives but C-S-H was found to form along with ettringite with the addition of borax in the initial stage of hydration.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.2
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• pp.114-117
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• 2004

Rates of $H_2$ uptake into $Pt/MoO_3$ were measured for the noncalcined and $200^{\circ}C$ calcined $Pt/MoO_3$. Amount of $H_2$ uptake for $200^\circ{C}$calcined $Pt/MoO_3$ was greater than the amount of noncalcined $Pt/MoO_3$. From these two experiments, it was found that the rates of $H_2$ desorption were proportional to the increase of desorption temperature. XPS demonstrated that Cl reduced more faster in ITR after calcination at $200^{\circ}C$. This inducd smaller amount of residual chlorine at adlineation sites between Pt and $MoO_3$ substrates. This resulted in opening the more channel of hydrogen pathway into more $MoO_3$particles and controled the kinetics of hydrogen uptake.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.74.1-74.1
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• 2021

밀러-유리 실험으로 알려진 전기방전 실험은 지구초기대기를 모사하여 아미노산을 합성하여, 지구에서 생명의 기원을 연구하는 실험중의 하나이다. 메탄(CH₄), 암모니아(NH₃), 질소(N₂) 가스를 주입하고 전기방전으로 에너지를 가했다. 그 결과 용액에서는 아미노산인 글라이신(C₂H₅NO₂), 알라닌(C₃H₇NO₂), 히스티딘(C₆H₉N₃O₂), 프롤린(C₅H₉NO₂), 발린(C₅H₁₁NO₂)이 검출되었고, 기존 Miller 1953과 Parker et al. 2014의 결과와 비교하였다. 전기방전에서는 C₂ Swan Band 와 CN emission을 발견하였다. 이 두 방출선들은 혜성에서도 일반적으로 보여지는 방출선들이다.