• Journal of Korean Society on Water Environment
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• v.32 no.1
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• pp.46-51
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• 2016

In this study, we synthesized a combination of graphene oxide (GO) and titanium dioxide (TiO₂) and confirm that GO can be used for CO₂ photoreduction. TiO₂ exhibited highly efficient combination with other conventional electric charges generated by these paration phenomenon for suppression of hole-electron recombination. This improved the efficiency of CO₂ photoreduction. The synthetic form of GO-TiO₂ used in this study was agraphene sheet surrounded by TiO₂ powder. Efficiency and stability were enhanced by combination of GO and TiO₂. In a CO₂ photoreduction experiment, the highest CO conversion rate was 0.652 μmol/g·h in GO10-TiO₂ (2.3-fold that of pure TiO₂) and the highest CH₄ production rate was 0.037 μmol/g·h in GO0.1-TiO₂ (2.4-fold that of pure TiO₂). GO enhances photocatalytic efficiency by functioning as a support and absorbent, and enabling charge separation. With increasing GO concentration, the CH₄ level decreases to~45% due to decreased transfer of electrons. In this study, TiO₂ together with GO yielded a different result than the normal doping effect and selective CO₂ photoreduction.

• Journal of Korean Society on Water Environment
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• v.36 no.2
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• pp.116-124
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• 2020

This study aims to identify the characteristics of organic matter and pollutant sources using water quality and stable isotope ratios (δ¹⁵N, δ¹³C) of the two inflow tributaries (Gulpo (GP) and Anyang (AY) streams). Water samples were analyzed in June and September 2018, and the results showed that the concentrations of nutrients, such as TN and NO₃-N, were increased at GP4, which is located at the downstream of sewage treatment facilities(STFs). TOC and TN ratios showed a strong positive correlation (R² = 0.77, p<0.01) at all points except for GP4. The results of GP's stable isotope ratio analysis do not appear to be a constant cluster compared to AY because GPs with large amounts of pollutants from the industry (metal processing companies, etc.) have less tributary, shorter waterway and significantly different external sources. This could be attributed to different sources of external inflow despite its smaller number of tributaries and shorter waterways than AY. In the first half of the year, the δ¹⁵5N of GP4 was affected by discharge of STFs, while AY3 seemed to have an influence of tributary than the discharge of STFs. Consequently, using water quality, stable isotope ratio and C/N, the sources of contamination in two streams with different contaminants were identified and origin was estimated.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.114-114
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• 2018

Among the various volatile organic compounds (VOCs) emitted by the plant, floral scent plays a key role in attracting pollinators for reproduction and mediates ecological interactions. Floral scent is an important trait and industry drives the competition for flowers with novel scents. Chrysanthemum is one of the well-known ornamental plants and is a popular cut flower across the world. Floral scent and the genes responsible for the floral scent emission are poorly studied in chrysanthemum. In the present study, floral scent and the expression pattern of floral scent genes were analyzed in two chrysanthemum cultivars 'Golden Egg' and 'Gaya Glory'. Initially, intensity of the floral scent in five developing stages of flower including 'budding (B), bud developing (BD), initial blooming (IB), almost open (AO) and open flower (OF)' was analyzed using electronic nose (E-nose) with six metal oxide sensors. Based on the distance analysis, different stages of flower showed different relative intensity of scent according to the sensory evaluation. Although the scent pattern differed by stage, scent intensity was strongest in the OF stage in the completely opened flower in both the cultivars. Further, expression pattern of six genes in the floral scent pathway including FDS, IDI, ISPH, TPS2, TPS5 and TPS6 was observed in all the five stages of the flower in both the cultivars. The expression pattern of all the six genes differed by stage and the terpene synthase genes TPS2, TPS5 and TPS6 showed good expression levels in the $5^{th}$ flower stage compared to other stages. This study provides a preliminary data for understanding the regulation of floral scent in chrysanthemum.

• Journal of Environmental Science International
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• v.16 no.12
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• pp.1337-1343
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• 2007

The aim of this study was to isolate chicken feather-degrading bacteria with high keratinolytic activity and to investigate cultural conditions affecting keratinolytic enzyme production by a selected isolate. A chicken feather-degrading bacterial strain CH3 was isolated from poultry wastes. Isolate CH3 degraded whole chicken feather completely within 3 days. On the basis of phenotypical and 16S rDNA studies, isolate CH3 was identified as Bacillus thuringiensis CH3. This strain is the first B. thuringiensis described as a feather degrader. The bacterium grew with an optimum at pH 8.0 and $37^{\circ}C$, where maximum keratinolytic activity was also observed. The composition of optimal medium for keratinolytic enzyme production was feather 0.1%, sucrose 0.7%, casein 0.3%, $K_2HPO_4$ 0.03%, $KH_2PO_4$ 0.04%, $MgCl_2$ 0.01% and NaCl 0.05%, respectively. The keratinolytic enzyme had a pH and temperature optima 9.0 and $45^{\circ}C$, respectively. The keratinolytic activity was inhibited ethylenediaminetetraacetic acid, phenylmethylsulfonyl fluoride, and metal ions like $Hg^{2+},\;Cu^{2+}\;and\;Zn^{2+}$. The enzyme activated by $Fe^{2+}$, dithiothreitol and 2-mercaptoethanol.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.4
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• pp.149-153
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• 2017

Recently, significant amounts of gem-quality colorless HPHT synthetic melee diamond have produced for the jewelry industry. Consequently, there have been reports of cases of fraud in the world diamond business. For example, intentionally selling synthetic diamond as natural diamond or intentionally mixing a natural diamond parcel with a synthetic. As a result, the separation of natural from synthetic melee diamonds has become increasingly critical. At present, 10,000 cubic hinge presses are used for the production of synthetic diamond in China. From among these, reportedly 1,000 presses are used for gem-quality diamond production. One press can produce up to 10ct melee-size diamonds in 24 hours. Randomly occurring pinpoint or flux-metal inclusions are diagnostic identification clues. However, some synthetic diamonds require advanced laboratory method for identification. In order to ensure consumer confidence, it is essential to screen melees so as to distinguish all synthetic goods.

• Journal of the Korean Ceramic Society
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• v.47 no.6
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• pp.598-602
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• 2010

When metal oxides are added into crystalline glaze, colors of glaze and crystals are similar as colorants generally. But the case of NiO in zinc crystalline glaze is different from general color development. When NiO is added to zinc crystalline glaze it can develop two or three colors. The active use of color development mechanism by adding NiO to the zinc crystalline glaze to control color of the base glaze and crystal with stability is investigated. This report is expected to contribute to the ceramic industry in improving application of zinc crystalline glaze. For the experiment of NiO, the quantity of NiO additives is changed to the base glaze for the most adequate formation of willemite crystal from previous research and firing condition: temperature increasing speed $5^{\circ}C/min$, holding 1 h at $1270^{\circ}C$, annealing speed $3^{\circ}C/min$ till $1170^{\circ}C$, holding 2 h at $1170^{\circ}C$ then naturally annealed. The samples are characterized by X-ray diffraction (XRD), UV-vis, and Micro-Raman. The result of the procedure as follows; Ni substitutes for Zn ion then glaze develops blue willemite crystals, as if cobalt is used, on brown glaze base. When NiO quantity is increased to over 5 wt%, willemite size is decreased, and the density of the crystal is increased, at the same time $Ni_2SiO_4$ (olivine) phase, the second phase, has been developed. The excessive NiO is reacted with silicate in the glass then developed green $Ni_2SiO_4$ (olivine), and quantity of $Ni_2SiO_4$ (olivine) is increased as quantity of willemite is decreased. It is proved to create three colors, blue, brown and green by controlling the quantity of NiO to the zinc crystalline glaze and it will improve the multiple use of colors to the ceramic design.

• Journal of the Korean Institute of Gas
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• v.10 no.1 s.30
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• pp.32-37
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• 2006

Major components of refinery plants are exposed to various damage mechanisms depending on the operation condition, material selection and kinds of internal fluid. Inspection techniques and damage monitoring methods should be selected considering the damage mechanisms of the components. Hence, it is quite necessary to have an information system with a standardized database on the various damage mechanisms. In this study a damage information system with contents on the damage mechanisms included in API 571 code was developed. Concept of the screening table employed in USA and Japan was also adopted to identify the probable damage mechanisms from the information on operating temperature, internal fluid, metal used for the component and stress condition. This system can be used before the risk based inspection planning to identify key damage mechanisms involved.

• Journal of the Korean Electrochemical Society
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• v.10 no.2
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• pp.150-154
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• 2007

Redox complexes to transport electrodes from biomaterial to electrodes are very important part in commercial biosensor industry. A novel osmium redox complex was synthesized by the coordinating pyridine group with osmium metal. A novel osmium complex is described as $[Os(dme-bpy)_2(ap-im)Cl]^{+/2+}$. We have been studied the electrochemical characteristics of this osmium complex with electrochemical techniques such as cyclic voltammetry and chronoamperommetry. In order to immobilize osmium redox complexes on the electrode, we deposited gold nano-particles on screen printed carbon electrode(SPE). The electrical signal converts the osmium redox films into an electrocatalyst for glucose oxidation. The catalytic currents were monitored that the catalytic currents were linearly increased from 1 mM to 5 mM concentrations of glucose.

• Fashion & Textile Research Journal
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• v.6 no.4
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• pp.503-510
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• 2004

The study is one of fundamental researches for the development of future smart clothing and textile products with blocking properties from electromagnetic waves by analyzing human physical symptoms in using electromagnetic products in such an environments. Among various textiles in the experiment, nano silver has shown the best blocking performance from electromagnetic waves, which decreases depending on the distance. The power spectrum distribution and the incidence of electroencephalogram between blocking materials and aural stimuli has shown that, ${\beta}$, wave appeared to be active in all channels except for $T_4$, whereas all waves appeared with processed materials and especially with nano silver silk(NSS), ${\alpha}$, ${\beta}$, ${\theta}$, ${\gamma}$ waves appeared active in all regions. As for the brain mapping of ${\alpha}$ wave according to time, there found a strong activity in $P_3$, $P_4$ of the parietal lobe, with all materials on all time regions. With silk nylon metal(SNM) and NSS, it appeared strong in $F_3$, $F_4$ as well. As for ${\beta}$, wave, the activity appeared strong in frontal lobe before 7min. 30sec, where it tends to diminish abruptly in 7min. 30sec. to 13min. 30sec. region. After 13min., it regained gradually. With NSS, it appeared strong in all areas except for the farthest $T_4$. The appearance of ${\nu}$ wave can be deduced as it can affect human body with its toxic property while the silver particles become nano-sized. Therefore, the study conducted with human participants requires a proper particle size of it which would not penetrate cellular tissues and a proper binder and binding treatment for it, to prevent the physical fatigues and the potential diseases. However, it is highly required for back-up researches to verify various aspects in applying nano silver to textile products.

• Fashion & Textile Research Journal
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• v.14 no.3
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• pp.492-500
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• 2012

Cocoa is a popular drink for children and contains healthy polyphenols however; a deep brown stain is left when cocoa is spilled over clothes. The main pigments in cocoa are anthocyanins that change in washing solutions with different alkalinity and metals. The removal and color changes in a cocoa stain after washing with various pH solutions and water hardness were studied. Alkalinity and the water hardness of washing solutions were important factors for the removal of cocoa stains. The removal of cocoa things in washing solutions without detergent was low (and even became negative after removal and darker) in solutions with a pH 9 and above. The cocoa stain was not removed and only the fabric color faded, although the cocoa stained cloth was washed with Korea tap water that has a pH of 7. The cocoa stain removal in detergent solutions was conspicuously higher than for only water. Even in detergent solutions, the cocoa stain removal decreased as water hardness increased. Cocoa stain removal was more effective and the color dimmest when the stained cloth was washed in a solution without the metal cations, and the bleach added with the detergent at a temperature of $40^{\circ}C$ and for longer than 20 minutes. Effective and economical equipment for tap water softening for a washing machine should be developed and used to improve cocoa stain removal.