• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.3
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• pp.212-217
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• 2005

Desorption/ionization on silicon mass spectrometry (DIOS-MS) is a relatively new laser desorption/ionization technique for mass spectrometry without employing an organic matrix. This present study was carried to survey the experimental factors to improve the efficiency of DIOS-MS through electrochemical etching condition in structure and morphological properties of the porous silicon. The porous structure of silicon structure and its properties are crucial for the better performance of DIOS-MS and they can be controlled by the suitable selection of electrochemical conditions. The fabrication of porous silicon and ion signals on DIOS-MS were examined as a function of silicon orientation, etching time, etchant, current flux, irradiation, pore size, and pore depth. We have also examined the effect of pre- and post-etching conditions for their effect on DIOS-MS. Finally, we could optimize the electrochemical conditions for the efficient performance of DIOS-MS in the analysis of small molecule such as amino acid, drug and peptides without any unknown noise or fragmentation.

• Journal of Marine Bioscience and Biotechnology
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• v.11 no.2
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• pp.89-93
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• 2019

In this study, the stability of the extracted natural pigments against light, temperature, pH, metal ions, and antimicrobial activity were evaluated in marine bacteria Zooshikella sp. 17TA. The pigment of the strain used in the study was red with maximum absorption at a wavelength of 541 nm. The stability of the pigment was evaluated by measuring the absorbance while preserving for 15 days and examining the retention rate. After 15 days of irradiation, the pigment of this bacterium showed 98% retention in the dark and 91% retention in the temperature range of -20℃ ~ 30℃. When the pH was in the range 4-7, the retention was about 80%, and the retention rate was higher than 85% for all kinds of metal ions except for CuCl₂, ZnCl₂, and KCl. The bacterial pigments showed high stability under the given irradiated pH, temperature, and metal ion conditions and had shown activity against gram-positive strains. These results suggest that this highly conserved microbial pigment can be applied to the food industry.

• The Korean Journal of Zoology
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• v.7 no.1
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• pp.1-5
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• 1964

GamnH-irradiated aqueous solutions of triglycine were studied using low voltage electrophoresis, paper chromatography, and determination of carbonyl compound. Four generalizations can be made as follows: 1. One component from irradiated triglycine formed a complex with copper ions and had higher electronegativity than did triglycine. 2. Five components from irradiated triglycine were separated by paper chromatography; of these, two were identified. 3. Carbonyl compound formation in irradiated triglycine increased up to $5{\times}10^{20}\;ev/ml$ and decreased at higher doses up to $1.9{\times}10^{21}\;ev/ml$ indicating its participation in secondary reaction in the complex system. 4. The possibility of hydrolytic brcabtgc of peptide bond was indicated by the separation of glycine from irradiated triglycine.lycine.

• Proceedings of the Korean Vacuum Society Conference
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• 2001.02a
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• pp.214-214
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• 2001

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.226-227
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• 2008

Pentacene based TFT showed a degraded mobility and saturation current (Ion) after exposure to the high energy ultraviolet (UV). In this article, we optimize the thickness of UV resisted layer on OTFT to restrain the degradation from protect layer deposition and study the UV aging effect of pentacene based TFT. The OTFT deivce with UV resisted layer could keep over 50% mobility after suffered UV $10^3J$.

• KSBB Journal
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• v.27 no.3
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• pp.145-150
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• 2012

This study was accomplished using packed bed column reactors that contain nonsurface-modified polypropylene media and surface-modified media from hydrophobic surface property into hydrophilic property by ion beam irradiation. The objectives of this research was investigated the characteristics of organic compounds removal and microbe attachment from sewage of school cafeteria in these reactors. In 736.8 mg/L of the average inflow $COD_{Cr}$ concentration the reactors with and without surface modification showed 81.8% and 70.3% of average $COD_{Cr}$ removal efficiencies, respectively, which proves the $COD_{Cr}$ removal efficiency of surface-modified media reactor is higher than that of nonsurface-modified media reactor. After 90 days, there were maximum differences between modified system and non-modified system. In that time the maximum removal efficiency of $COD_{Cr}$ was 96.5% in modified system and was 85.2% in non-modified system that showed removal efficiency of surface-modified media system is 11.3% higher than that of nonsurface-modified media system. The average removal efficiency of SS was 80.4% for the surface modified system and 61.6% for the non-modified system under same condition. Also, the reactor of surface-modified media has advantage on microbe attachment and biofilm formation.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.195-198
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• 2002

A positron camera, consisting of a pair of Anger-type scintillation detectors, has been developed for verifying the ranges of irradiation beams in heavy-ion radiotherapy. Images obtained by a centroid calculation of photomultiplier outputs exhibit a distortion near the edge of the crystal plane in an Anger-type scintillation detector. The images of a $\^$68/Ge line source were detected and look-up tables were prepared for the position correction parameters. Asymmetry of the position distribution detected by the positron camera was prevented with this correction. As a result, a linear position response and a position resolution of 8.6 mm were obtained over a wide measurement field.

• Laser Solutions
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• v.3 no.2
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• pp.35-43
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• 2000

Laser direct patterning of the coated photoresit (PMER-NSG31B) layer was studied to make halftone dots on gravure printing roll. The selective laser hardening of photoresist by Ar-ion laser(wavelength : 333.6nm∼363.8nm) was controlled by the A/O modulator. The coating thickness in the range of 5㎛∼11㎛ could be obtained by using the up-down directional moving device along the vertically located roll. The width, thickness and hardness of the hardened lines formed under laser power of 200∼260㎽ and irradiation time of 4.4∼6.6$\mu$ sec/point were investigated after developing. The hardened width increased according to the increase of coating thickness. Though the hardened thickness was changed due to the effect of the developing solution, the hardened layer showed good resistance to the scratching of 2H pencil. Also, the hardened minimum line widths of 10㎛ could be obtained. The change of line width was also found after etching, and the minimum line widths of 6㎛ could be obtained. The hardened lines showed the good resistance to the etching solution. Finally, the experimental data could be applied to make gravure halftone dots using the developed imaging process, successfully.

• International Journal of Precision Engineering and Manufacturing
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• v.3 no.1
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• pp.26-32
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• 2002

Laser direct patterning of the coated photoresist (PMER-NSG31B) layer was studied to make halftone dots on the gravure printing roll. The selective laser hardening of the photoresist by Ar-ion laser(wavelength: 333.6∼363.8 nm) was controlled by the A/O modulator. The coating thickness in the range of 5∼11㎛ could be obtained by using the up-down directional moving device along the vertically located roll. The width, thickness and hardness of the hardened lines farmed under the laser power of 200∼260mW and irradiation time of 4.4∼6.6 $\mu$ sec/point were investigated after developing. The hardened width increased as the coating thickness increased. Though the hardened thickness was changed due to the effect of the developing solution, the hardened layer showed good resistance to the scratching of 2H pencil. Also, the hardened minimum line width of 10㎛ could be obtained. The change of line width was also found after etching, and the minimum line widths of 6㎛ could be obtained. The hardened lines showed the good resistance to the etching solution. Finally, the experimental data could be applied to make gravure halftone dots using the developed imaging process, successfully.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.45-50
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• 2000

We have investigated the influence of columnar defects (CD) on the vortex dynamics in pristine and iodine-intercalated Bi$_2$Sr$_2$CaCu$_2$O$_{8+{\delta}} single crystals from do SQUID magnetization measurements. Especially, the temperature dependence of the irreversibility fields, H$_{irr}$(T), were studied. Anisotropy ratio ${\gamma}$, estimated from the fitting to the 2-dimensional melting model (A. Schilling et al., Phys. Rev. Lett. 71 1899 (1993)) in higher fields than the matching field B$_{\phi}$ at low temperature region, turns out to be decreased by the iodine-intercalation and additionally by the heavy-ion irradiation.