• 한국재료학회지
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• 제33권11호
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• pp.497-501
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• 2023

ZnO/Cu/ZnO (ZCZ) thin films were deposited at room temperature on a glass substrate using direct current (DC) and radio frequency (RF, 13.56 MHz) magnetron sputtering and then the effect of post-deposition electron irradiation on the structural, optical, electrical and transparent heater properties of the films were considered. ZCZ films that were electron beam irradiated at 500 eV showed an increase in the grain sizes of their ZnO(102) and (201) planes to 15.17 nm and 11.51 nm, respectively, from grain sizes of 13.50 nm and 10.60 nm observed in the as deposited films. In addition, the film's optical and electrical properties also depended on the electron irradiation energies. The highest opto-electrical performance was observed in films electron irradiated at 500 eV. In a heat radiation test, when a bias voltage of 18 V was applied to the film that had been electron irradiated at 500 eV, its steady state temperature was about 90.5 ℃. In a repetition test, it reached the steady state temperature within 60 s at all bias voltages.

• Journal of Electrochemical Science and Technology
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• 제6권3호
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• pp.75-80
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• 2015

We introduce a new synthesis method to prepare small TiO₂ nanoparticles with a narrow particle size distribution, which is achieved by electron beam (E-beam) irradiation. The effects of E-beam irradiation on the synthesis of TiO₂ nanoparticles and the electrochemical performance of TiO₂ nanoparticles as alternative anode materials for Li-ion batteries are investigated. The TiO₂ nanoparticles induced by E-beam irradiation present better cycling performance and rate capability than the TiO₂ nanoparticles synthesized by normal hydrolysis reaction. The better electrochemical performance is attributed to small particle size and narrow particle size distribution, resulting in the large surface area that provides innumerable reaction sites and short diffusion length for Li⁺ through TiO₂ nanoparticles.

• Macromolecular Research
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• 제14권6호
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• pp.640-645
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• 2006

Polyethylene of bimodal molecular weight distribution was irradiated with an electron beam. The thermal and mechanical properties were examined by DSC, small and wide angle X-ray scattering and static tensile test according to the crystal morphology of the irradiated samples. The crystal morphology change upon irradiation, as revealed by wide angle X-ray scattering, correlated well with the changes in melting enthalpy, whereas the lamellar thickness and the amorphous gap thickness remained virtually unchanged at irradiation doses up to 500 kGy. Crosslinks in the crystal domains became evident at an energy level of 250 kGy, resulting in reduced crystallinity and crystal size of the (110) and (200) planes. The samples became stiff and brittle with increased irradiation dose, which seem to be more relevant to the amount of cross links than the crystal morphology changes.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.377-378
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• 2008

Space charge formation in various glass materials under electron beam irradiation was investigated. Charging of spacecraft occurs in plasma and radiation environment. Especially, we focused on an accident caused by internal charging in a glass material that was used as the cover plate of solar panel array, and tried to measure the charge distribution in glass materials under electron beam irradiation by using a PEA (Pulsed Electro-Acoustic method) system. In the case of a quartz glass (pure $SiO_2$), no charge accumulation was observed either during or after the electron beam irradiation. On the contrary, positive charge accumulation was observed in glass samples containing metal-oxide components. It is found that the polarity of the observed charges depends on the contents of the impurities. To identify which impurity dominates the polarity of the accumulated charge, we measured charge distributions in several glass materials containing various metal-oxide components and calculated the trap energy depths from the charge decay characteristics of all glass samples. Furthermore, the dependence of the polarity of accumulated charges on the component of glass materials is discussed by using the models of energy bands.

• Bulletin of the Korean Chemical Society
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• 제34권5호
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• pp.1397-1400
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• 2013

The influence of electron beam irradiation on photocatalytic activity of $TiO_2$ thin films was investigated. $TiO_2$ thin films were prepared by anodization of Ti foil, and they were then subjected to an 1 MeV electron beam. Changes in physical properties and photocatalytic activity of $TiO_2$ before and after e-beam irradiation were investigated. The crystallinity of the synthesized materials was investigated by X-ray diffraction, and the oxidation states of both titanium and oxygen were determined by X-ray photoelectron spectroscopy (XPS). The density of donor ($N_d$) and flat band potential ($E_{fb}$) were investigated by Mott-Schottky analysis, and photocurrent was measured under a 1kW Xenon lamp illumination. After e-beam irradiation, significant change of Ti oxidation state was observed. $Ti^{3+}/Ti^{4+}$ ratio increased mainly due to the surface reduction by electron, and photocurrent was observed to increase with e-beam irradiation.

• 공업화학
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• 제33권3호
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• pp.322-327
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• 2022

Fucoidans were degraded by hydrogen peroxide under the electron beam (2.5 MeV) with various radiation doses (5 kGy, 10 kGy, 15 kGy, and 20 kGy) at room temperature. The degradation property was analyzed with a gel permeation chromatography (GPC-MALLS) method. An average molecular weight of fucoidan decreased from 99,956 at the irradiation dose of 0 kGy to 6,725 at the irradiation dose of 20 kGy. The solution viscosity of fucoidans showed a similar pattern to the molecular weight change. The number of chain breaks per molecule (N) increased with increasing the irradiation dose and concentration of hydrogen peroxide. The radiation yield of scission value markedly increased with increasing the irradiation dose up to 15 kGy. Also a 10% hydrogen peroxide concentration was more efficient than that of 5%. The structures of degraded fucoidan samples were studied with Fourier transform infrared spectroscopy (FT-IR). The results showed that the degradation process did not significantly change the chemical structure or the content of sulfate group. The sulfur content of each sample was determined with an Elemental Analyzer. With increasing the concentration of hydrogen peroxide, the ratios of sulfur/carbon, hydrogen/carbon, and nitrogen/carbon slightly decreased. The antioxidant activities of fucoidans were investigated based on hydroxyl radical scavenging activities. The ability of fucoidan to inhibit the hydroxyl radical scavenging activity was depended on its molecular weight.

• 치과방사선
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• 제22권1호
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• pp.43-53
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• 1992

The purpose of this study was to investigate the effects of irradiation on the microvascular structure of the submandibular gland in rats. For this study, 110 male rats were singly irradiated with the dose of 10Gy or 20Gy to their neck region by 6MV X-irradiation and sacrificed on the 1st, 3rd, 7th, 14th and 28th day after irradiation. The author observed distribution and structural changes of the microvasculature in rat submandibular glands using a scanning electron microscope by forming vascular resin casting. The author observed ultrastructural changes of the endothelial cells using a transmission electron microscope, and also histologic changes using a light microscope at Hematoxylin and Eosin staining and PAS staining process. The results of the irradiation effects on the microvasculature in rat submandibular gland were as follows: By light microscopic examination, the dilation of small vessels were observed until the 7th day after irradiation. After then, the vascular constriction and decrease in number of small vessels were noticed. Changes were greater on 20Gy irradiated group than on lOGy irradiated group. The reaction to PAS staining at acinar cells was decreased just after irradiation, but gradually recovered with days. There was no specific difference between two irradiated groups. By scanning electron microscopic examination, general findings on the two irradiated groups were similar. The dilation of conduits and meandering were observed on the 3rd day after irradiation. Decrease of capillary density and blunt ended small vessels were appeared on the 7th day after irradiation. After that, findings of the tortuous and twisted vascular running and coarseness of capillary lumen were increased. Changes were greater on 20Gy irradiated group than on l0Gy irradiated group. By transmission electron microscopic examination, increase of the formation of cytoplasmic process was observed on the 3rd day after irradiation. After that, swelling of endothelial cell and bridge formation of cytoplasmic processes were also observed, but destruction of endothelial cell and loss of basement membrane were observed only on 20Gy irradiated group on the 28th day after irradiation.

• 한국축산식품학회지
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• 제34권4호
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• pp.464-471
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• 2014

Ground lean pork was irradiated by an electron beam or X-rays to compare the effects of two types of radiation generated by a linear accelerator on the quality of Bologna sausage as a model meat product. Raw ground lean pork was vacuum packaged at a thickness of 1.5 cm and irradiated at doses of 2, 4, 6, 8, or 10 kGy by an electron beam (2.5 MeV) or X-rays (5 MeV). Solubility of myofibrillar proteins, bacterial counts, and thiobarbituric acid reactive substance (TBARS) values were determined for raw meat samples. Bologna sausage was manufactured using the irradiated lean pork, and total bacterial counts, TBARS values, and quality properties (color differences, cooking yield, texture, and palatability) were determined. Irradiation increased the solubility of myofibrillar proteins in a dose-dependent manner (p<0.05). Bacterial contamination of the raw meat was reduced as the absorbed dose increased, and the reduction was the same for both radiation types. Differences were observed only between irradiated and non-irradiated samples (p<0.05). X-ray irradiation may serve as an alternative to gamma irradiation and electron beam irradiation.

• 한국식품영양과학회지
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• 제34권3호
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• pp.433-437
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• 2005

전자선 조사가 건조된 오징어의 미생물학적 안전성과 품질에 미치는 영향을 확인하였다. 전자선은 2-16 kGy의 선량으로 각각 조사하여 대조구와 비교하였다. 실험 결과 전자선에 의해 건조된 오징어에 존재하는 미생물 수가 유의적으로 감소하는 것을 확인하였다 건조된 오징어에 존재하는 총 호기성 세균, 곰팡이와 효모, 대장균 군의 D/sub 10/ value는 각각 8.57, 4.60, 8.10 kGy로 나타났다. 전자선 조사된 시료 및 대조구에 대한 Hunter 색차계의 L, a, b 값을 측정 한 결과 유의적 차이가 없는 것으로 나타났고, 관능검사의 경우도 조사된 시료와 대조구와의 큰 변화는 나타나지 않았다. 따라서 전자선 조사로 인해 건조된 오징어의 미생물학적 안전성과 품질 개선의 가능성을 확인하였다.

• 한국식품과학회지
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• 제37권2호
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• pp.308-311
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• 2005

전자선 조사가 통후추 분말과 시판 선식의 미생물학적 안전성과 품질에 미치는 영향을 확인하였다. 전자선은 통후추 분말과 시판 선식에 2-16kGy의 선량으로 각각 조사하였다. 실험결과 전자선에 의해 통후추 분말과 시판 선식에 오염된 미생물 수가 유의적으로 감소하는 것을 확인하였다. 통후추 분말과 시판 선식에 존재하는 호기성 세균의 $D_{10}\;value$는 각각 5.32 kGy와 1.56 kGy로 나타났고, 곰팡이와 효모의 $D_{10}\;value$는 각각 2.54 kGy와 2.14 kGy로 나타났다. 전자선 조사된 시료 및 대조구에 대한 Hunter 색차계의 L, a b 값을 측정한 결과 큰 변화는 없는 것으로 나타났고, 관능 검사의 경우도 조사된 시료와 대조구와의 유의적 차이는 나타나지 않았다. 따라서 전자선 조사로 인해 통후추 분말과 시판 선식의 미생물학적 안전성과 품질 개선의 가능성을 확인하였다.