• Korean Journal of Veterinary Service
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• v.35 no.3
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• pp.197-205
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• 2012

Despite of a long history of the sulfur on the disease healing effect, there were limited ways of applying sulfur to animal and human. We have developed the detoxified sulfur (non toxic sulfur) method to make it practical and mass production possible through laboring for many years. This study practiced scanning electron microscope (SEM), Energy dispersive X-ray spectrometer (EDS) and secondary ion mass spectrometry (SIMS) analysis to investigate the physicochemical aspect of detoxified sulfur. We also performed the oral toxicity experiment to mice, and anti-bacterial test of the detoxified sulfur. Based on the SEM, EDS and SIMS results, the united particles in the mass form with the similar component intensity with the raw sulfur were observed, and hydrogen sulfide ion (HS-) component which is regarded as a toxic matter, was decreased after detoxification. Indeed, toxicity test on the mice (10 males, 10 females) showed no clinical, histopathological changes with the 5 times amount (2,500 mg/kg) of the actual doses. However, the male-mice showed decreased in body weight by 23.6%, 24.3% in the 7th, 14th day, respectively, after detoxified sulfur. Moreover, the female-mice administered the detoxified sulfur showed decreased in body weight by 28.7% (P<0.05) than that in the control group on the 14th day. The result of antibacterial test on the detoxified sulfur showed antibacterial effect (27%) to inhibit the growth of Staphylococcus aureus. It is shown that detoxified sulfur can be used as feed additive and has an affect on the farm perfomance.

• Journal of the Korean Ceramic Society
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• v.54 no.5
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• pp.429-437
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• 2017

Micro hollow plate type silica with low refraction properties was synthesized and its hollow structure was applied as an optical structure to develop a light diffusion material that simultaneously satisfies the requirements of good light diffusibility, high transmissibility, and high luminance. The developed light diffusion material was applied to a light diffusion film and the film's optical properties were assessed. Hollow silica was synthesized by precipitation method using $Mg(OH)_2$ core particles, sodium silicate, and ammonium sulfate as the silica precursors. The concentration of the silica precursor was adjusted to control hollow silica shell thickness. The total light transmittance of the light diffusion film composed of the hollow silica was 94.55%, which was 4.57% higher than that of the PC film; new film's haze was 71.20%, which was 70.9% higher. Furthermore, the luminance increased by 5.34% compared to that of the light source. The reason for the results is not only that the micro plate type hollow silica, which has a low refractive property, played a role in reducing the difference in refractive index between the medium boundaries, but also that there was a light-concentrating effect due to the changing of light paths to the front direction inside the hollow structure. Optical simulation verified the enhanced optical properties when hollow silica was applied to the light diffusion film.

• Archives of Pharmacal Research
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• v.29 no.8
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• pp.707-711
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• 2006

Bifidobacteria-loaded alginate poly-l-lysine microparticles (bap microparticles) were prepared using an air atomization method and then freeze-dried. The viability of the bap microparticles was investigated as a function of the amount of the bifidobacteria cultures, and the addition of a yeast extract, cryoprotectants, antioxidants and neutralizer. The size of the bap microparticles with and without the bifidobacteria was $84.8{\pm}28.5\;{\mu}m$ ($mean{\pm}standard$ deviation) and $113.1{\pm}38.5\;{\mu}m$, respectively. The surface morphology was slightly ellipsoid and wrinkled regardless of the incorporating bifidobacteria. The viability gradually decreased with increasing freeze-drying time. Free-flowing powdered bap microparticles were obtained at least 12 h after freeze-drying the wetted slurry of bap microparticles. However, the particles tended to aggregate when either lactose or ascorbic acid was added. The addition of a yeast extract, cryoprotectants (glycerol and lactose), antioxidants ($NaHSO_3$ and ascorbic acid) and neutralizer $(Mg_3(PO_4)_2)$ resulted in a significantly higher viability of the bifidobacteria in the bap microparticles after freeze-drying (0.34-1.84 log) compared with the culture alone.

• Journal of the Korean Vacuum Society
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• v.17 no.6
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• pp.576-581
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• 2008

High-quality double-walled carbon nanotubes (DWNTs) were synthesized without defects and amorphous carbonaceous particles by catalytic decomposition method at $800^{\circ}C$ in high yield. As-synthesized carbon materials almost consist of DWNT bundles with a diameter 12 - 20 nm.. The DWNTs rope have uniform diameter about 2 - 5 um and length up to several tens micrometer. DWNTs is inner tube diameter 0.9 - 1.5 nm and outer tube 1.6 - 2.2 nm. We investigate the crystallinity of DWNTs by TEM and Raman spectroscopy. We also found that the Fe-Mo bimetallic catalyst was active as a very efficient catalyst for the synthesis of DWNTs with the catalyst decomposition method. Our results also indicate that Tetra Hydro Furan (THF) is a very ideal carbon source for the synthesis of DWNTs.

• Journal of Environmental Science International
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• v.11 no.7
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• pp.651-662
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• 2002

Weather elements were observed by the AWS (Automatic Weather System) and dustfall particles were collected by the modified American dust jar (wide inlet bottle type) at 4 sampling sites in Busan area from March. 1999 to February, 2000. Thirteen chemical species (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Ni, Pb, Si, and Zn) were analyzed by AAS and ICP. The purposes of this study were to estimate qualitatively various bulk deposition flux of dustfall and insoluble components by applying regional and seasonal wind intensity. Frequency of wind speed were found in order of low(1-3m/s), very low(<1m/s), medium(3-8m/s) and high(>8m/s), and annual mean had higher range at low(1-3m/s) for 56.3%. Strong negative linear correlation were observed between dustfall and wind direction (northeastern and eastern), but strong positive linear correlation were observed between dustfall and wind direction (western and northwestern) at industrial, commercial and coastal zone(p<0.05). While a negative correlation were observed between wind speed frequency of very low(<1 m/s) and dustfall, and positive correlation were observed between wind speed frequency of low(1-3m/s) and dustfall in coastal zone(p<0.05). The correlation coefficient was observed 0.556 between wind speed frequency of low(1-3m/s) and Ni by commercial zone(p<0.05). The correlation coeffcient show well-defined insoluble trace metals (Al, Ca, Cr, Cu, Fe, Pb, and Zn) and wind speed frequency of low(1-3m/s) at coastal zone, which was found significant difference(p<0.01).

• Journal of Environmental Health Sciences
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• v.19 no.3
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• pp.52-57
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• 1993

This study was carried out to investigate the air pollution in Hwasoon Nulitjae tunnel for two months, from August 1992 to September 1992. The total suspended particles were collected by high volume air sampler at inside and outside of Hwasoon Nulitjae tunnel, of which major water soluble component and heavy metalic element were analyzed. Size distribution and respirable mass fraction of aerosol at inside were measured by filters on nine stages Andersen air sampler. The average concentration of TSP at inside was 657.57 $\mu$g/m$^3$, which appeared about 9.2 times as high as that of 71.47 $\mu$g/m$^3$ at outside. The decrease effect caused by using new tunnel was 31.2%. As a result of correlation analysis between concentration of TSP at inside of Hwasoon Nulitjae tunnel and that at outside, correlation coefficient was 0.713. The average concentrations of SO$_4^{2-}$ , NO$_3^-$, CI$^-$ were 43.02 $\mu$g/m$^3$, 19.86 $\mu$g/m$^3$, 4.96 $\mu$g/m$^3$, those of NH$_4^+$, Na$^+$, K$^+$ 1.42 $\mu$g/m$^3$, 4.45 $\mu$g/m$^3$, 2.89 $\mu$g/m$^3$ and those of Ca$^{2+}$, Mg$^{2+}$, Pb$^{2+}$ 3.92 $\mu$g/m$^3$, 2.27 $\mu$g/m$^3$. 1.52 $\mu$g/m$^3$, respectively. It was estimated that mass fraction rate of respirable particle at inside was about 84.54% of aerosol. The average concentration of suspended particle to be collected by Andersen sampler was 478.90 $\mu$g/m$^3$, this was about 72.8% of that by high volume air sampler.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.4
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• pp.242-248
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• 2014

We have five soil series of pan soils in South Korea out of 391 series: Gangreung, Bugog, Yeongog, Jangweon, and Pogog. Productivity decreases in pan soils as pan horizons impede percolation and capillary rise of water and interrupt root extension. This study was performed to investigate pedogenic processes of pan soils mainly located in footslope and river terrace by analyzing physicochemical properties and soil micro-morphology. Korean pan soils belong to Alfisols, Ultisols, or Inceptisols and have udic or aquic soil moisture regime, mesic temperature regime, and mixed mineral substances. Texture of pan horizons selected for the present study was mainly silty clay loam with clay contents ranging from 26.3 to 45.3%. Bulk density of the pan horizons ranged from 1.4 to $2.1Mg\;m^{-3}$ and their soil structure were subangular or angular structure. In terms of micro-morphological structure, Bt horizon of Gangreung series was formed as platy and striated b-fabric structure possibly affected by uplift of coastal terrace following clay sedimentation by flood. Jangweon series showed micro-morphology of massive structure and crystallic b-fabric as macropores between coarse debris established by debris fall in slope were filled with silt-sized particles. The Bt horizons having massive structure and striated b-fabric in Yeongog, Pogog, and Bugog series implies that those horizons experienced horizontal mass flow after clay accumulation.

• Korean Journal of Materials Research
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• v.24 no.5
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• pp.236-242
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• 2014

Fabrication of reaction-bonded $Al_2O_3$ (RBAO) ceramics using Al-Zn-Mg alloy powder was studied in order to improve traditional RBAO ceramic processing using Al powder. The influence on reaction-bonding and microstructure, as well as on physical and mechanical properties, of the particulate characteristics of the $Al_2O_3$-Al alloy powder mixtures after milling, was revealed. Variation of the particulate characteristics of this $Al_2O_3$-Al alloy powder mixture with milling time was reported previously. To start, the $Al_2O_3$-Al alloy powder mixture was milled, reaction-bonded, post-sintered, and characterized. During reaction-bonding of the $Al_2O_3$-Al alloy powder mixture compacts, oxidation of the Al alloy took place in two stages, that is, there was solid- and liquid-state oxidation of the Al alloy. The solid-state oxidation exhibited strong dependence on the density of surface defects on the Al-alloy particles formed during milling. Higher milling efficiency resulted in less participation of the Al alloy in reaction-bonding. This was because of its consumption by chemical reactions during milling, and subsequent powder handling, and could be rather harmful in the case of over-milling. In contrast to very little dependence of oxidation of the Al alloy on its particle size after milling, the relative density, microstructure, and flexural strength were strongly dependent on particle size after milling (i.e., on milling efficiency). The relative density and 4-point flexural strength of the RBAO ceramics in this study were ~98% and ~365 MPa, respectively, after post-sintering at $1,600^{\circ}C$.

• Toxicological Research
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• v.28 no.4
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• pp.217-224
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• 2012

In recent decades, titanium dioxide ($TiO_2$) nanoparticles have been used in various applications, including paints, coatings, and food. However, data are lacking on the toxicological aspects associated with their use. The aim of this study was to assess the inhalation toxicity of $TiO_2$ nanoparticles in rats by using inhalation exposure. Male Wistar rats were exposed to $TiO_2$ nanoparticles for 2 weeks (6 hr/day, 5 days/week) at a mean mass concentration of $11.39{\pm}0.31mg/m^3$. We performed time-course necropsies at 1, 7, and 15 days after exposure. Lung inflammation and injury were assessed on the basis of the total and individual cell counts in bronchoalveolar lavage fluid (BALF), and by biochemical assays, including an assay for lactate dehydrogenase (LDH). Furthermore, histopathological examination was performed to investigate the lungs and nasal cavity of rats. There were no statistically significant changes in the number of BALF cells, results of biochemical assays of BALF and serum, and results of cytokine analysis. However, we did observe histopathological changes in the nasal cavity tissue. Lesions were observed at post-exposure days 1 and 7, which resolved at post-exposure day 15. We also calculated the actual amounts of $TiO_2$ nanoparticles inhaled by the rats. The results showed that the degree of toxicity induced by $TiO_2$ nanoparticles correlated with the delivered quantities. In particular, exposure to small particles with a size of approximately 20 nm resulted in toxicity, even if the total particle number was relatively low.

• Proceedings of the KAIS Fall Conference
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• 2011.12a
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• pp.196-199
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• 2011

In this study we synthesized mesoporous carbon supported CuO by using mesoporous silica i.e. SBA-15 as the template and cupric nitrate trihydrate ($Cu(NO_3)_23H_2O$)as copper source. The porous CuO was characterized with XRD, TGA, SEM and BET. The result reveals porous CuO has good crystal structure with uniform size of spherical crystal particles. The surface are a ($S_{BET}$) of porous CuO was found to be $153.46m^2g^{-1}$ with a total pore volume ($V_p$)of$0.1516cm^3g^{-1}$ and average pore size of 3.9 nm which was much higher than that of commercial CuO ($S_{BET}$, $7.6m^2g^{-1}$; $V_p$, $0.01cm^3g^{-1}$). The obtained porous CuO was studied for adsorption of $CO_2$and the maximum $CO_2$ adsorption capacity was found to be 67.5 mg/g of the sorbent at $25^{\circ}C$.