• Journal of the Korean Chemical Society
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• v.29 no.6
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• pp.575-581
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• 1985

Ultraviolet spectrophotometric investigations have been carried out on the systems of benzene, naphthalene and phenanthrene with iodine in carbon tetrachloride. The results reveal the formation of the one to one molecular complexes. The equilibrium constants were obtained in consideration of that absorption maxima due to the formation of the charge transfer complexes shift to blue with increasing temperature. Thermodynamic parameters for the formation of the charge transfer complexes were calculated from these values. These results indicate that the stabilities of the complexes formed between polynuclear aromatics and iodine increase with the number of aromatic rings. This may be a measure of the relative basicities of polynuclear aromatics toward iodine, which is explained in terms of the resonance of the interaction between aromatics and iodine. The results in this study were, additionally, compared with those of the polymethylbenzene series to be discussed the reason for them.

• Korean Journal of Materials Research
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• v.20 no.1
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• pp.31-36
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• 2010

Methylene blue (MB) was degraded by $TiO_2$ and ZnO deposited on an activated carbon fiber (ACF) surface under UV light. The ACF/$TiO_2$ and ACF/ZnO composites were characterized by BET, SEM, XRD, and EDX. The BET surface area was related to the adsorption capacity for composites. The SEM results showed that titanium dioxide and zinc oxide are distributed on the ACF surface. The XRD results showed that the ACF/$TiO_2$ and ACF/ZnO composites contained a unique anatase structure for $TiO_2$ and a typical hexagonal phase for ZnO respectively. These EDX spectra showed the presence of peaks of Ti element on ACF/$TiO_2$ composite and peaks of Zn element on the ACF/ZnO composite. The blank experiments for either illuminating the MB solution or the suspension containing ACF/$TiO_2$ or ACF/ZnO in the dark showed that both illumination and the catalyst were necessary for the mineralization of organic dye. Additionally, the ACF/$TiO_2$ composites proved to be efficient photocatalysts due to degradation of MB at higher reaction rates. The addition of an oxidant $([NH_4]_2S_2O_8)$ led to an increase of the degradation rate of MB for ACF/$TiO_2$ and ACF/ZnO composites.

• Advances in nano research
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• v.15 no.4
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• pp.295-304
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• 2023

In this paper, a powerful photocatalyst based on carbon nanocomposite is developed in order to obtain a new material applicable in water treatment and especially for the discoloration of effluents used in the textile industry. For that, TiO₂-graphene nanocomposites have been successfully synthesized by a mixture of Functionalized Graphene Sheet (FGS) and tetrachlorotitanium complexes to form FGS-TiO₂ nanocomposite. In the presence of an anionic surfactant, we used a new chemical process to functionalize graphene sheets in order to make them an excellent medium for blocking and preventing the aggregation of TiO₂ nanoparticles. The components of these nanocomposites are characterized by means of X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), which confirms the successful formation of the FGS-TiO₂ nanocomposite. It was found that the TiO₂ nanoparticles were dispersed uniformly on the graphene plane which possesses better charge separation capability than pure TiO₂. The FGS-TiO₂ nanocomposites exhibited higher photocatalytic activity compared to pure TiO₂ for the removal of three dyes: such as Methylene Blue (MB), Bromophenol Blue (BB) and Alizarin Red-S (AR) in water. The removal process was fast and more efficient with FGS-TiO₂ nanocomposite in daylight (in the absence of UV irradiation) compared to pure TiO₂ nanoparticles without and under UV in all pH range.

• Journal of Conservation Science
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• v.27 no.2
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• pp.223-229
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• 2011

Buddha painting cultural properties couldn't avoid the change of colors and the exfoliation phenomenon by the characteristic of material and environmental factors. Especially, because in the beginning of the fine crack and the decoloration phenomenon on the surface of pigment would be significantly decrease stability of the whole object, it is necessary to take particular measure. Therefore, this is a study on conservation of Avalokitesvara in Potalaka in Hyeondeungsa in Gapyeong. It treated damaged parts of the object, carried out backing papers and matching colors. And then, it examined scientific analysis of pigments. Also, it performed nondestructive testing like XRF, FT-IR, and image microscope to investigate the quality of the material of hanji using the object and the component and characteristic of pigments. As a result, FT-IR spectrum matching Korean traditional paper(hanji) was detected in hanji of Avalokitesvara in Potalaka in Hyeondeungsa. The black pigment making a thin layer over the white pigment would estimate carbon compounds of unconfirmed ink stick or soot as XRF and FT-IR. Also, the white pigment was lead white($PbCO_3{\cdot}Pb(OH)_2$) involving Pb(Lead) and a carbonate. It was observed that the crystal of blue pigment had the different sizes of the particles from the microscope. In the case of this blue pigment, it showed cobalt blue and lead white was mixed when it used because both Cu and Pb were highly detected in XRF data.

• The Korean Journal of Malacology
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• v.31 no.3
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• pp.203-212
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• 2015

This study was performed to describe the influence of temperature on the clearance rate and ingestion rate of the blue mussel, Mytilus galloprovincialis with three food organisms and habitat location (shell size) of mussel. Food organisms used in this experiments were Isochrysis galbana, Chaetoceros didymus and Prorocentrum dentatum. The size of mussels inhabiting higher midlittoral zone was smaller than those of lower midlittoral zone. Regardless of the kind of food organisms, filtration rates and ingestion rates of higher midlittoral mussels were higher than those of lower midlittoral mussels in experiment temperature conditions. The variation of filtration rate and ingestion rate showed same tendency with temperature. Filtration rates and ingestion rates increased with temperature, and recorded maximum values at $20-25^{\circ}C$ of temperature, and thereafter decreased gradually. Theoretical optimum temperatures showing maximum filtration rates and ingestion rates estimated from polynomial regression curves were also in the range of $20-25^{\circ}C$. Blue mussels showed different variation of filtration rate and ingestion rate with the kind of food organisms. Filtration rates and ingestion rate based on cell number were similar regardless of habitat location(tidal elevation) and food organisms. Ingestion rates based on carbon content showed very high values in case of P. dentatum beside I. galbana and C. didymus as food organism.

• Journal of the Korean Wood Science and Technology
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• v.38 no.1
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• pp.27-35
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• 2010

To evaluate the basic characteristics and adsorption properties of commercial wood charcoal, we investigated the proximate analysis, porosimetry analysis, methylene blue adsorption, removal ratios of formaldehyde, and removal ratio of ethylene gas. Fixed carbon contents of traditional black and white charcoal, and mechanical charcoal were 51.8~76.6%, 72.9~84.6%, and 48.5~80.3%, respectively. Refining degrees of the most traditional black charcoal were 9, and those of white charcoal and mechanical charcoals were zero. Specific surface area of traditional black charcoal was 0.1~13.7 $m^2/g$, which was quite lower than that of white charcoal (53.2~372.6 $m^2/g$) and mechanical charcoals (224.3~464.6 $m^2/g$). Also, amounts of methylene blue adsorption were quite lower in black charcoal (0.53~1.97 mg/g) compared with white charcoal (2.68~7.68 mg/g) and mechanical charcoal (11.63~26.10 mg/g). Removal ratios of formaldehyde of the black charcoal were 11.4~26.7%, which is quite similar to white charcoal (17.9~34.9%) and mechanical charcoal (5.5~25.8%). Removal ratios of ethylene gas for traditional black charcoal, traditional white charcoal, and mechanical charcoal were 2.2~43.5%, 21.7~39.1%, 21.7~39.1%, respectively. There was no significant difference in the removal ratios of formaldehyde and ethylene gas among traditional black charcoal, traditional white charcoal, and mechanical charcoal.

• Journal of the East Asian Society of Dietary Life
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• v.20 no.5
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• pp.735-742
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• 2010

Biogenic amines are synthesized by microbial decarboxylation for the putrefaction or fermentation of foods containing protein. Although biogenic amines such as histamine, tyramine, and putrescine are required for many physiological functions in humans and animals, consumption of high amounts of biogenic amines can cause toxicological effects, including serious gastrointestinal, cutaneous, hemodynamic, and neurological symptoms. In this study, a novel amperometric biosensor wasdeveloped to detect biogenic amines. The biosensor consisted of a working electrode, a reference electrode, a counter electrode, an enzyme reactor with immobilized diamine oxidase, an injector, a peristaltic pump and a potentiostat. A working electrode was fabricated with a glassy carbon electrode (GCE) by coating functionalized multi-walled carbon nanotubes (MWCNT-$NH_2$) and by electrodepositing Prussian blue (PB) to enhance electrical conductivity. A sensor system with PB/MWCNT-$NH_2$/GCE showed linearity in the range of $0.5 {\mu}M{\sim}100 {\mu}M$ hydrogen peroxide with a detection limit of $0.5 {\mu}M$. The responses for tyramine, 2-phenylethylamine, and tryptamine were 95%, 75%, and 70% compared to that of histamine, respectively. These results imply that the biosensor system can be applied to the quantitative measurement of biogenic amines.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.2
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• pp.239-251
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• 2024

In this study, a hydrogen fuel cell process based on methanol was developed to reduce greenhouse gas emissions. In Case1, the methanol fuel engine system was designed to investigate the emission of exhaust gas when methanol was supplied as fuel instead of gasoline to the engine. In Case2, a hydrogen fuel cell system was designed by adding a methanol reforming system to Case1. This hybrid system produced gray hydrogen and combined the output of the engine and fuel cell to drive the ship. However, gray hydrogen emits carbon in the process of producing hydrogen. To address this problem, a carbon capture and utilization (CCU) system was added to Case3. The CO2 of the flue gas discharged from Case2 was synthesized with gray hydrogen to produce blue methanol. The results of the case studies revealed that the optimal operating conditions were 220 ℃, 500 kPa, SCR = 1.0, and flow ratio = 0.7. The system of Case3 reduced carbon emissions by 42% compared with that Case1. Thus, the hybrid system of Case3 could considerably reduce the ship's CO2 emissions.

• Journal of the Korean Chemical Society
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• v.27 no.1
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• pp.38-45
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• 1983

Aziridine derivatives were utilized for the formation of aziridine N-oxides at low temperature, which were subject to easy decomposition and/or rearrangement like the protonated aziridines at room temperature. t-Butyl nitroso compound formed by the decomposition of N-oxide is easily characterized by its blue color and it is the major product in case that no branched alkyl groups are substituted on the carbon atoms of the aziridine ring and the stationary groups on the nitrogen are inert to rearrange the oxide such as the t-butyl group. The oxidative rearrangement products, however, are mainly formed when the substituents are methyl or ethyl group on the carbon atoms. It is interesting to see that the sigmatropic rearrangement of 2-ethyl aziridine gave only cis olefinic compound selectively in case that t-butyl group was substituted on the nitrogen, whereas N-hydroxy aziridine compounds were formed exclusively when t-butyl group was replaced with ethyl group.

• Journal of Microbiology and Biotechnology
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• v.16 no.2
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• pp.226-231
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• 2006

Several white-rot fungi are able to produce extracellular lignin-degrading enzymes such as manganese peroxidase (MnP), lignin peroxidase (LiP), and laccase. In order to enhance the production of laccase and MnP using Trametes versicolor KCTC 16781 in suspension culture, the effects of major medium ingredients, such as carbon and nitrogen sources, on the production of the enzymes were investigated. The decolorization mechanism in terms of biodegradation and biosorption was also investigated. Among the carbon sources used, glucose showed the highest potential for the production of laccase and MnP. Ammonium tartrate was a good nitrogen source for the enzyme production. No significant difference in the laccase production was observed, when glucose concentration was varied between 5 g/l and 30 g/l. As the concentration of nitrogen source increased, a lower MnP activity was observed. The optimal C/N ratio was 25 for the production of laccase and MnP. When the concentrations of glucose and ammonium tartrate were simultaneously increased, the laccase and MnP activities increased dramatically. The maximum laccase and MnP activities were 33.7 U/ml at 72 h and 475 U/ml at 96 h, respectively, in the optimal condition. In this condition, over 90% decolorization efficiency was observed.