• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.16-17
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• 2005

Local lifetime control by ion implantation has become an useful tool for production of modern power devices. In this work, punch-through diodes were irradiated with protons for the high speed power diode fabrication. Proton irradiation was executed at the various energy and dose conditions. Characterization of the device was performed by I-V, C-V and Trr measurement. We obtained enhanced reverse recovery time characteristics which was about 45% of original device and about 73% of electron irradiated device. The measurement results showed that proton irradiation was able to effectively reduce minority carrier lifetime.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.3
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• pp.216-221
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• 2006

Lifetime control technique by proton implantation has become an useful tool for production of modern power devices. In this work, punch-through type diodes were irradiated with protons for the high speed power diode fabrication. Proton irradiation which was capable of controlling carrier's lifetime locally was carried out at the various energy and dose conditions. Characterization of the device was performed by current-voltage, capacitance-voltage and reverse recovery time measurement. We obtained enhanced reverse recovery time characteristics which was about $45\;\%$ of original device reverse recovery time and about $73\;\%$ of electron irradiated device reverse recovery time. The measurement results showed that proton irradiation technique was able to effectively reduce minority carrier lifetime without degrading the other characteristics.

• Biomolecules & Therapeutics
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• v.12 no.3
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• pp.145-150
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• 2004

Inflammation is a frequent radiation-induced reaction following therapeutic irradiation. Treatment of human umbilical endothelial cells (HUVEC) with ${\gamma}$-irradiation (${\gamma}$IR) induces the expression of adhesion proteins such as intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin. Since the upregulation of these proteins on endothelial cell Surface has been known to be associated with inflammation, interfering with the expression of adhesion molecules is an important therapeutic target. In the present study, we demonstrate that vitamin C inhibits ${\gamma}$IR induced expression of ICAM-1, VCAM-1, and E-selectin on HUVEC in a dose- and time dependent manner. Vitamin C a1so inhibited the production of Nitric oxide (NO) induced by ${\gamma}$IR. These data suggest that vitamin C has therapeutic potential for the treatment of various inflammatory disorder associated with an increase of endothelial leukocyte adhesion molecules.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.90-90
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• 2010

We investigated the modification of optical response properties of titanium dioxide (TiO2) coatings on the ceramic water-purification filters by using ultraviolet-visible absorption spectroscopy and X-ray diffraction. The TiO2 coatings were prepared on ceramic substrate by e-beam evaporation method. These amorphous TiO2 were turned into anatase phase by heat treatment at $700^{\circ}C$ for 2 hours. The doping of N atoms into the TiO2 coatings was done by using 70KeV of N＋ ion implantation with the dose of $1.0{\times}1017$ ions/cm2, followed by post-irradiation heat treatment at $550^{\circ}C$ for 2 hours. Methylene blue test of TiO2 coatings to solar irradiation showed that the post-evaporation heated TiO2 was photocatalytic and N-doped TiO2 reacted to the visible part of solar irradiation.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2000.09a
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• pp.21-21
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• 2000

We performed this study to determine the effect of Bu-Zhong-Yi-Qi-Tang, as a prescription of traditional Oriental medicine, and its major ingredients on jejunal crypt survival, endogenous spleen colony formation, and apoptosis in jejunal crypt cells of mice irradiated with high and low dose of r-radiation. Bu-Zhong-Yi-Qi-Tang administration before irradiation protected the jejunal crypts (p<0.0001), increased the formation of endogenous spleen colony (p<0.05) and reduced the frequency of radiation-induced apoptosis (p<0.05). (omitted)

• Journal of radiological science and technology
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• v.20 no.1
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• pp.91-96
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• 1997

Male rats of Albino strain were divided into four groups. The radioprotective effect of treatment with S-2(3-aminopropylamino)ethylphosphorothioic acid(WR-2721) using the dose of 200 mg/kg by intraperitonial injection on rats for 20 min prior to whole body x-ray irradiation (8 Gy) was studied. The harzardous effects of x-ray irradiation were greatly corrected In the treated group. The concentrations of total serum cholesterol, HDL-cholesterol, triglyceride, and phospholipid were greatly affected, showing insignificant changes in the treated group of animals. The drastic hyperglycemic effect of x-ray irradiation in the untreated group decreased to a normal level. These results show the potentiality of WR-2721 as a radioprotective agent.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2004.05a
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• pp.181-184
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• 2004

This study was conducted to investigate the adequate irradiation dose to eliminate harmful fungi inoculated if beef jerky with a 10% higher moisture content and improved textural property. Aspergillus flavus (approximately $10^6\;CFU/cm^2$) was tested in broth, spore suspension, and inoculated jerky. $D_{10}$ values of A. flavus were 0.36 kGy in the broth and suspension, and 0.47 kGy in the jerky. The results indicate that gamma irradiation can be effectively used to control the fungus growth in beef jerky with an improved quality and higher moisture content.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.2
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• pp.291-295
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• 1998

The ovalbumins obtained from hen's and duck's egg white were irradiated with up to 100 kGy at room temperature. The purified proteins were evaluated for their in vitro digestibility by incubating successively with pepsin and pancreatin conjugate. Amino acid compositions and SDS-PAGE pattern in these proteins were also analyzed. The obtained results indicated that gamma irradiation within the tested dose range(up to 100kGy) produced no statistically significant changes in the in vitro digestibility an amino acid compositions. Analysis of gamma-irradiated ovalbumins by SDS-PAGE revealed radiolysis of ovalbumin into proteins or peptides of low molecular weights.

• Journal of Radiation Industry
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• v.2 no.1
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• pp.15-19
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• 2008

In order to develop a water-solubility and biocompatibility, chemically modified chitosan, N,O-carboxymethylchitosan (NOCC), was synthesized and the NOCC hydrogels were prepared by using ${\gamma}-ray$ irradiation instead of chemical reagents. The FT-IR spectroscopy, swelling behavior, gel content and mechanical property such as gel strength of the hydrogel were measured. When the NOCC solution concentration was 15 wt% and the dose of irradiation was less than 50 kGy, the NOCC hydrogels had an excellent hydrophilicity and exhibited a good swelling behavior and mechanical properties.

• Journal of Radiation Industry
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• v.8 no.1
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• pp.1-5
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• 2014

This study investigated the reduction of microbial population and sensory properties in red pepper powders irradiated by gamma ray, electron beam, and X-ray. Populations of total aerobic bacteria and yeast & molds in red pepper powders were decreased by irradiation treatment in a dose-dependent manner. Gamma ray, electron beam, and X-ray at doses above 8 kGy caused 100% inhibition on growth of aerobic bacteria in red pepper powders. Inhibitory activity of X-ray on sterilization of red pepper powders was significantly equal to or higher compared to gamma ray and electron beam. Color and off flavor in red pepper powders were no significant difference among the control and samples irradiated with gamma ray, electron beam, and X-ray. As a result, the gamma ray, electron beam, and X-ray irradiation can be used to sterilize the microbial growth in red pepper powders without quality loss.