• Journal of Hydrogen and New Energy
• /
• v.13 no.3
• /
• pp.224-232
• /
• 2002

CdS-$TiO_2$ nano-composite sol was prepared by the sol-gel method in organic solvents at room temperature and further hydrothermal treatment at various temperatures to control the physical properties of the primary particles. Again, CdS-$TiO_2$ composite particulate films were made by casting CdS-$TiO_2$ sols onto $F:SnO_2$ conducting glass and then heat-treatment at $400^{\circ}C$. Physical properties of these 61ms were further controlled by the surface treatment with $TiCl_4$, aqueous solution. The photo currents and hydrogen production rates measured under the experimental conditions varied according to the $CdS/[CdS+TiO_2]$ mole ratio and the mixed-sol preparation method. For $CdS-TiO_2$ composite sols prepared in IPA, CdS particles were homogeneously surrounded by $TiO_2$ particles. Also, the surface treatment with $TiCl_4$ aqueous solution caused a considerable improvement in the photocatalytic activity, probably as a result of close contacts between the primary particles by the etching effect of $TiCl_4$. It was found that the photoelectrochemical performance of these particulate films could be effectively enhanced by this approach.

• International Journal of Advanced Culture Technology
• /
• v.7 no.4
• /
• pp.125-136
• /
• 2019

The radish skin and radish greens are an edible part of the radish. But they are removed before eating the radish and used as a byproduct or an animal feed material because of their tough and rough texture. Melanin is a pigment that gives colour to our skin. But increased production of melanin can turn into benign or malignant tumours. These days due to global warming, the amount of Ultra violet (UVB) rays has been extensively increased with sunlight. Due to this, a phenomenon called exogenous photo aging is widely observed for all skin colour and types. As a result of this phenomenon, a set of enzymes called matrix metalloproteinases (MMP's) that serves as degradation enzymes for extracellular matrix proteins mainly collagen is increased, causing depletion in collagen and resulting in early wrinkles formation. Therefore in our study we used the murine melanoma cell line B16/F10 to study the melanogenesis inhibition by Heated radish extract (HRE) in vitro and we used HRM-2 hair less mice exposed to artificial UVB for checking the efficacy of Heated radish extract in vivo. Furthermore, we prepared a 3% Heated radish extract (HRE) cream and checked its effects on human skin. Our results have clearly demonstrated that Heated radish extract (HRE) have potently suppressed the tyrosinase activity and melanin production in B16/F10 cells. It had also reduced the expression of components involved in melanin production pathway both transcriptionally and transitionally. In in vivo studies, HRE had potently suppressed the expression of MMP's and reduced the wrinkle formation and inhibited collagen degradation. Moreover, on human skin, ginseng cream increased the resilience, skin moisture and enhanced the skin tone. Therefore in light of these findings, we conclude that HRE is an excellent skin whitening and antiaging product.

• Clean Technology
• /
• v.18 no.4
• /
• pp.355-359
• /
• 2012

For effectively photochemical hydrogen production, Ti ions (0.01, 0.10, 0.50 mol%) impregnated $WO_3$ ($Ti/WO_3$) nanometer sized particles were prepared using a impregnation method as a photocatalyst. The characteristics of the synthesized $Ti/WO_3$ photocatalysts were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence spectra (PL), atomic force microscope (AFM), and electrostatic force microscope (EFM). The evolution of $H_2$ from methanol/water (1/1) photo-splitting over $Ti/WO_3$ photocatalysts was enhanced compared to those over pure $TiO_2$ and $WO_3$ photocatalysts; 3.02 mL of $H_2$ gas was evolved after 8 h when 0.5 g of a 0.10 mol% $Ti/WO_3$ catalyst was used.

• Journal of Korean Society of Water and Wastewater
• /
• v.24 no.6
• /
• pp.775-788
• /
• 2010

The decomposition of 2,4,6-trinitrotoluene (TNT) and the mass balance of nitrogen (N) species as products were investigated in a UV/H2O2system by varying pH, concentrations of $H_2O_2$, and $O_2$. All experiments were conducted in a semi-batch system employing a 50 mL reaction vessel and a coil-type quartz-tube reactor. In contrast with previous studies employing batch mode, TNT decomposition in the semi-batch mode was proportionally enhanced by increasing $H_2O_2$ concentration to 10 mM (0.034%), indicatingthat an inhibitory effect of excess $H_2O_2$on hydroxyl radical (${\cdot}OH$) can be negligible. N compounds are released as $NO_2^-$ in the early stages of the reaction, but $NO_2^-$ is rapidly oxidized to $NO_3^-$ by means of ${\cdot}OH$. $NH_4^+$ was also detected in this study and showed gradually the increase with increasing reaction time. In this study, $NH_4^+$ production can involve the reduction of nitro group of TNT concurrent with the production of $NO_3^-$. Of the N species originating from TNT decomposition, 12 ~ 72% were inorganic forms (i.e. [$NO_3^-$] + [$NO_2^-$] + [$NH_4^+$]). This result suggests that the large remaining N portions indicate that unidentified N compounds can exist.

• Journal of the Korean Society of Safety
• /
• v.32 no.4
• /
• pp.100-106
• /
• 2017

Outline map is used for the description and reconstruction of the traffic accident. One way to produce the outline map is by adopting detailed measurements from the accident site such as final position of the vehicle and pedestrian, width of the road, and locations of the oil and tire marks. This method consumes large amount of time not to mention that of the production of detailed version as fine as the picture of the site. Aerial recording equipment so called HeliCam can produce an outline map that can substitute that of manual method with even faster production time and higher resolution. However, the produced picture have errors which are resulted by distortion due to the characteristics of camera and direction of the photographing. This paper provides correction of the distortion of oultline map produced by HeliCam using Adobe Photoshop and PC-Rect. The result showed resonable error range less than 6 cm(0.1%) for $60m{\times}30m$ area taken by HeliCam. The presented method develops outline map with small error, which is useful to traffic accident analysis, and traffic accident cases analyzed in this study were also.

• Molecules and Cells
• /
• v.37 no.2
• /
• pp.172-177
• /
• 2014

A glycosyltransferase, YjiC, from Bacillus licheniformis has been used for the modification of the commercially available isoflavonoids genistein, daidzein, biochanin A and formononetin. The in vitro glycosylation reaction, using UDP-${\alpha}$-D-glucose as a donor for the glucose moiety and aforementioned four acceptor molecules, showed the prominent glycosylation at 4' and 7 hydroxyl groups, but not at the $5^{th}$ hydroxyl group of the A-ring, resulting in the production of genistein 4'-O-${\beta}$-D-glucoside, genistein 7-O-${\beta}$-D-glucoside (genistin), genistein 4',7-O-${\beta}$-D-diglucoside, biochanin A-7-O-${\beta}$-D-glucoside (sissotrin), daidzein 4'-O-${\beta}$-D-glucoside, daidzein 7-O-${\beta}$-D-glucoside (daidzin), daidzein 4', 7-O-${\beta}$-D-diglucoside, and formononetin 7-O-${\beta}$-D-glucoside (ononin). The structures of all the products were elucidated using high performance liquid chromatography-photo diode array and high resolution quadrupole time-of-flight electrospray ionization mass spectrometry (HR QTOF-ESI/MS) analysis, and were compared with commercially available standard compounds. Significantly higher bioconversion rates of all four isoflavonoids was observed in both in vitro as well as in vivo bioconversion reactions. The in vivo fermentation of the isoflavonoids by applying engineered E. coli $BL21(DE3)/{\Delta}pgi{\Delta}zwf{\Delta}ushA$ overexpressing phosphoglucomutase (pgm) and glucose 1-phosphate uridyltransferase (galU), along with YjiC, found more than 60% average conversion of $200{\mu}M$ of supplemented isoflavonoids, without any additional UDP-${\alpha}$-D-glucose added in fermentation medium, which could be very beneficial to large scale industrial production of isoflavonoid glucosides.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.41 no.1
• /
• pp.7-12
• /
• 2008

To develop a whitening agent, cytotoxicity of the soluble collagen isolated from Todarodes pacificus (CIT) was evaluated. CIT tested for cytotoxicity on human dermal fibroblast (CCD-986sk) was exhibited very low cytotoxicity. Because tyrosinase is the key enzyme for melanin biosynthesis, the use of various tyrosinase inhibitors is a common practice for whitening purpose in cosmetics. Tyrosinase inhibitory activity and melanin production assay were measured to confirm the whitening effect. The inhibitory effect of MMP-1 in UV-irradiated human dermal fibroblast was also performed. CIT showed strong inhibition potency on tyrosinase by 51.5% at 0.2 mg/mL which increased the inhibition by increasing the concentration of CIT, and showed 69.1% inhibition at 1.0 mg/mL. CIT showed strong inhibition effect on melanin production with 82% at 1.0 mg/mL. The CIT also reduced about 76% expression of MMP-1 in UV-irradiated CCD-986sk cell at 1.0 mg/mL. From the preliminary observations, we suggest that the collagen isolated from CIT could be a potential source of natural skin-whitening and anti-aging agents for the photo-damaged skin.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.08a
• /
• pp.312-312
• /
• 2011

In SiH4/H2 discharge for growth process of hydrogenated amorphous silicon (a-Si:H), silane polymers, produced by SiH2 + Sin-1H2n ${\rightarrow}$ SinH2n+2, have no reactivity on the film-growing surface. However, under the SiH2 rich condition, high silane reactive species (HSRS) can be produced by electron collision to silane polymers. HSRS, having relatively strong reactivity on the surface, can react with dangling bond and form Si-H2 networks which have a close correlation with photo-induced degradation of a-Si:H thin film solar cell [1]. To find contributions of suggested several external plasma conditions (pressure, frequency and ratio of mixture gas) [2,3] to suppressing productions of HSRS, some plasma characteristics are studied by numerical methods. For this study, a zero-dimensional global model for SiH4/H2 discharge and a one-dimensional particle-in-cell Monte-Carlo-collision model (PIC-MCC) for pure SiH4 discharge have been developed. Densities of important reactive species of SiH4/H2 discharge are observed by means of the global model, dealing 30 species and 136 reactions, and electron energy probability functions (EEPFs) of pure SiH4 discharge are obtained from the PIC-MCC model, containing 5 charged species and 15 reactions. Using global model, SiH2/SiH3 values were calculated when pressure and driving frequency vary from 0.1 Torr to 10 Torr, from 13.56 MHz to 60 MHz respectively and when the portion of hydrogen changes. Due to the limitation of global model, frequency effects can be explained by PIC-MCC model. Through PIC-MCC model for pure SiH4, EEPFs are obtained in the specific range responsible for forming SiH2 and SiH3: from 8.75 eV to 9.47 eV [4]. Through densities of reactive species and EEPFs, polymerization reactions and production of HSRS are discussed.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.4
• /
• pp.1137-1144
• /
• 2013

$TiO_2$ composites with seven different carbon materials (activated carbons, graphite, carbon fibers, single-walled carbon nanotubes, multi-walled carbon nanotubes, graphene oxides, and reduced graphene oxides) that are virgin or treated with nitric acid are prepared through an evaporation method. The photocatalytic activities of the as-prepared samples are evaluated in terms of $H_2$ production from aqueous methanol solution (photo-catalytic reduction: PCR) and degradation of aqueous pollutants (phenol, methylene blue, and rhodamine B) (photocatalytic oxidation: PCO) under AM 1.5-light irradiation. Despite varying effects depending on the kinds of carbon materials and their surface treatment, composites typically show enhanced PCR activity with maximum 50 times higher $H_2$ production as compared to bare $TiO_2$. Conversely, the carbon-induced synergy effects on PCO activities are insignificant for all three substrates. Colorimetric quantification of hydroxyl radicals supports the absence of carbon effects. However, platinum deposition on the binary composites displays the enhanced effect on both PCR and PCO reactions. These differing effects of carbon materials on PCR and PCO reactions of $TiO_2$ are discussed in terms of physicochemical properties of carbon materials, coupling states of $TiO_2$/carbon composites, interfacial charge transfers. Various surface characterizations of composites (UV-Vis diffuse reflectance, SEM, FTIR, surface area, electrical conductivity, and photoluminescence) are performed to gain insight on their photocatalytic redox behaviors.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.4
• /
• pp.1182-1190
• /
• 2014

$Cd_{1-x}Zn_xS$-sensitized $K_4Nb_6O_{17}$ composite photocatalysts (designated $Cd_{1-x}Zn_xS/K_4Nb_6O_{17}$) were prepared via a simple deposition-precipitation method. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDS), $N_2$ sorption, ultraviolet-visible light diffuse reflectance spectroscopy (UV-Vis DRS), photoluminescence measurements (PL), and X-ray photoelectron spectroscopy (XPS). The $Cd_{0.8}Zn_{0.2}S$ particles were scattered on the surface of $K_4Nb_6O_{17}$, and had a relatively uniform size distribution around 50 nm. The absorption edge of $K_4Nb_6O_{17}$ was shifted to the visible light region and the recombination of photo-generated electrons and holes suppressed after $Cd_{0.8}Zn_{0.2}S$ loading. The $Cd_{0.8}Zn_{0.2}S$(25 wt %)/$K_4Nb_6O_{17}$ composite possessed the highest photocatalytic activity for hydrogen production under visible light irradiation, evolving 8.278 mmol/g in 3 h. Recyclability tests were performed, and the composite photocatalysts were found to be fairly stable. The mechanism of charge separation between the photogenerated electrons and holes at the $Cd_{0.8}Zn_{0.2}S/K_4Nb_6O_{17}$ composite was discussed.