• Applied Chemistry for Engineering
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• v.9 no.1
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• pp.129-134
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• 1998

Conversion of propane to acrylonitrile via ammoxidation was studied using physically mixed catalysts composed of $Nb_2O_5(10{\sim}30wt%)$ and $V_{0.4}Mo_1Te_{0.1}$. Catalytic activities of ammoxidation were improved by adding strong acidic niobium oxide to $V_{0.4}Mo_1Te_{0.1}$, the selectivities to acrylonitrile+propylene being remained constant. The maximum activity was obtained at the mixing ratio 25wt% niobium oxide in $Nb_2O_5-V_{0.4}Mo_1Te_{0.1}$. Niobium oxide was found to be a selective catalyst for the oxidative dehydrogenation of propane.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.247-250
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• 2008

Biomass gasification is a promising technology for producing a fuel gas which is useful for power generation systems. In biomass gasification processes, tar formation often causes some problems such as pipeline plugging. Thus, proper tar treatment is necessary. So far, nickel (Ni)-based catalysts have been intensively studied for the catalytic tar removal. However, the deactivation of Ni-based catalysts takes place because of coke deposition and sintering of Ni metal particles. To overcome these problems, we have been using ruthenium (Ru)-based catalyst for tar removal. It is reported by Okada et al., that a Ru/$Al_2O_3$ catalyst is very effective for preventing the carbon deposition during the steam reforming of hydrocarbons. Also, this catalyst is more active than the Ni-based catalyst at a low steam to carbon ratio (S/C). Benzene was used for the tar model compound because it is the main constituent of biomass tar and also because it represents a stable aromatic structure apparent in tar formed in biomass gasification processes. The steam reforming process transforms hydrocarbons into gaseous mixtures constituted of carbon dioxide ($CO_2$), carbon monoxide (CO), methane ($CH_4$) and hydrogen ($H_2$).

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1341-1345
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• 2011

A novel ruthenium(II) complex, [$RuCl_2(DMSO)_2$(PhenTPy)] has been synthesized by the condensation of $RuCl_2(DMSO)_4$ with (1-(1,10-phenanthrolinyl)-2,5-di(2-thienyl)-1H-pyrrole)[PhenTPy] in $CHCl_3$ solution. The [$RuCl_2(DMSO)_2$(PhenTPy)] complex modified electrode was fabricated through the electropolymerization of the monomer in a 0.1 M tetrabutylammonium perchlorate (TBAP)/$CH_2Cl_2$ solution, to take advantage of the electronic communication between metal ion center by the conjugated backbone. The UV-visible spectroscopy (UV), mass spectrometry (MS), and cyclic voltammetry (CV) were employed to characterize the [$RuCl_2(DMSO)_2$(PhenTPy)] complex and its polymer (poly-Ru(II)Phen complex). The poly-Ru(II)Phen complex modified electrode exhibited an electrocatalytic activity to the oxidation of acetaminophen and the catalytic property was used for the analysis of acetaminophen at the concentration range between 0.09 and 0.01 mM in a phosphate buffer solution (pH 7.0).

• Journal of Korean Society for Atmospheric Environment
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• v.9 no.4
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• pp.288-294
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• 1993

Flue gas control systems for small-scale combustors must be designed to provide highly effective removal of three criteria pollutants (S $O_{2}$, N $O_{x}$ and particulate matter), and must be safe, reliable and small. These requirements make dry, regenerative clean-up process particularly attractive and this paper describes a new concept for integrated pollutant control : a filter comprised of layered, gas permeable membranes that act as an S $O_{2}$ sorbant, a N $O_{x}$ reduction catalyst and a particulate filter. A mixed metal oxide sorbent, Cu-Ce was used as a sorbent/catalyst and the activity was compared with Cu-7Al. The S $O_{2}$ removal eficiency of Cu-Ce was increased with temperature increase up to 500$^{\circ}$C and the catalytic activity for NO was higher than that of Cu-7Al. By the sulfation of Cu-Ce, the reduction activity was increased at the temperature higher than 350$^{\circ}$C. The regeneration of Cu-Ce was very fast and some amount of elemental sulfar was found.

• Microbiology and Biotechnology Letters
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• v.23 no.1
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• pp.60-67
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• 1995

Methanol assimilating yeast, Hansenula sp. MS-364 that has high productivity with methanol as carbon and energy source has been preserved at dept. of Microbiological engineering. Purification and properties of alcohol oxidase (E.C.1.1.3.13: oxygen oxidoreductase) were investigated in the methanol assimilating yeast, Hansenula sp. MS-364. Alcohol oxidase is related to the catalytic reaction that degrades alcohol to aldehyde and peroxide. The methanol oxidizing enzyme was purified by ammonium sulfate precipitation, DEAE-Sephadex A-50 chromatography and gel filtration on Sepharose 6B from cell-free extract. The purified enzyme preparation gave a single band in the sodium dodesyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The molecular weight of the enzyme was calculated to be about 576,000 and molecular weight of subunit was also calculated to be 72,000. The optimal pH and temperature of the enzyme reaction were pH 7.5 and 37$\circ$C, respectively. The enzyme was unstable in acidic pH and higher temperature. The enzyme was not specific for methanol and also oxidized lower primary alcohols. The Km value for methanol was 2.5 mM and that for ethanol was 1.66 mM. The enzyme was heavily inhibited by metal ions such as Hg$^{2+}$, Ag$^{2+}$, Cu$^{2+}$. The high concentration of EDTA and sulfhydryl reagents strongly inhibited the enzyme activity. The component of coenzyme was determined to flavin adenine dinucleotide.

• Journal of Microbiology and Biotechnology
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• v.19 no.10
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• pp.1184-1190
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• 2009

A thermostable extracellular $\beta$-mannanase from the culture supernatant of a fungus Aspergillus niger gr was purified to homogeneity. SDS-PAGE of the purified enzyme showed a single protein band of molecular mass 66 kDa. The $\beta$-mannanase exhibited optimum catalytic activity at pH 5.5 and $55^{\circ}C$. It was thermostable at $55^{\circ}C$, and retained 50% activity after 6 h at $55^{\circ}C$. The enzyme was stable at a pH range of 3.0 to 7.0. The metal ions $Hg^{2+}$, $Cu^{2+}$, and $Ag^{2+}$ inhibited complete enzyme activity. The inhibitors tested, EDTA, PMSF, and 1,10-phenanthroline, did not inhibit the enzyme activity. N-Bromosuccinimide completely inhibited enzyme activity. The relative substrate specificity of enzyme towards the various mannans is in the order of locust bean gum>guar gum>copra mannan, with $K_m$ of 0.11, 0.28, and 0.33 mg/ml, respectively. Since the enzyme is active over a wide range of pH and temperature, it could find potential use in the food-processing industry.

• Journal of Microbiology and Biotechnology
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• v.28 no.4
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• pp.579-587
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• 2018

For biotechnological production of high-valued ${\beta}-{\text\tiny{D}}$-hexyl glucoside, the catalytic properties of Hanseniaspora thailandica BC9 ${\beta}$-glucosidase purified from the periplasmic fraction were studied, and the transglycosylation activity for the production of ${\beta}-{\text\tiny{D}}$-hexyl glucoside was optimized. The constitutive BC9 ${\beta}$-glucosidase exhibited maximum specific activity at pH 6.0 and $40^{\circ}C$, and the activity of BC9 ${\beta}$-glucosidase was not significantly inhibited by various metal ions. BC9 ${\beta}$-glucosidase did not show a significant activity of cellobiose hydrolysis, but the activity was rather enhanced in the presence of sucrose and medium-chain alcohols. BC9 ${\beta}$-glucosidase exhibited enhanced production of ${\beta}-{\text\tiny{D}}$-hexyl glucoside in the presence of DMSO, and 62% of ${\beta}-{\text\tiny{D}}$-hexyl glucoside conversion was recorded in 4 h in the presence of 5% 1-hexanol and 15% DMSO.

• Journal of Microbiology and Biotechnology
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• v.22 no.11
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• pp.1501-1509
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• 2012

A novel bacterial strain, MG7, with high cellulase activity was isolated and identified by morphological characteristics and molecular phylogeny analysis as Paenibacillus barcinonensis. Maximum production of cellulase by MG7 was observed at pH 7.0 and $35^{\circ}C$. The enzyme was purified with a specific activity of 16.88 U/mg, the cellulase activity was observed in a zymogram, and its molecular mass (58.6 kDa) was confirmed by SDS-PAGE. The purified enzyme showed maximum activity at pH 6.0 and $65^{\circ}C$ and degraded cellulosic substrates such as carboxy methyl cellulose (CMC), Avicel, filter paper, and ${\beta}$-glucan. The enzyme showed stability with 0.5% concentration of various surfactants. The $K_m$ and $V_{max}$ of cellulase for CMC and Avicel were found to be 0.459mg/ml and 10.46mg/ml/h, and 1.01 mg/ml and 10.0 mg/ml/h, respectively. The high catalytic activity and its stability to temperature, pH, surfactants, and metal ions indicated that the cellulase enzyme by MG7 is a good candidate for biotechnological applications.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.2
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• pp.69-75
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• 1999

The characteristics of $H_2$ gas detection have been investigated using the Pt-MIS capacitor composed of the LPCVD nitride on the oxide. The flat band voltage shift is measured as 0.1 V in 1,000 ppm $H_2$ gas ambient and to be independent of Pt catalyst thickness. It is found that the flatband voltage shift is proportional to the hydrogen concentrations. The response and recovery time of Pt-MIS capacitor are 5 mins and 25 mins respectively. The samples of 30nm thick Pt revealed much higher sensitivity than that of 150nm samples. The samples of 150nm Pt showed that the flatband voltage shift of the device is due to the formation of the dipole layer of the adsorbed hydrogen atoms at the Pt-insulator interface.

• Korean Journal of Materials Research
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• v.11 no.8
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• pp.697-702
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• 2001

Effects of ammonia treatment on the morphologies of the catalytic metal films and carbon nanotubes subsequently synthesized via a thermal chemical vapor deposition method were investigated. An optimally controlled thermo-chemical process of ammonia treatment gave rise to a morphology of a dense distribution of vertically aligned carbon nanotubes. $NH_3$ treatment is a crucial key process to obtain vertically aligned carbon nanotubes. However, it was realized by a simple $NH_3$ treatment during synthesis at temperatures of $800-900^{\circ}C$ without any extra process. The structure and morphology of carbon nanotubes were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy.