• 열처리공학회지
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• 제30권4호
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• pp.164-168
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• 2017

Intense electron beam was irradiated on the CrAlN thin films deposited in SKD61 under different incident energies and then the effect of electron beam irradiation on the enhancement of surface hardness and wear resistance was investigated. Surface hardness and wear resistance of the CrAlN films is increased proportionally with the electron beam energy. While the surface hardness of as deposited CrAlN film is Hv ($0.1g{\cdot}f$) 450, the hardness oflectron irradiated (600 eV) film is Hv ($0.1g{\cdot}f$) 2050. The width of wear track of the untreated SKD61 is $X\_{\mu}m$, while the track-width of the electron irradiated CrAlN (600 eV) film is $787{\mu}m$, respectively. From the observed results, it is supposed that the optimal electron beam irradiation can be one of the useful surface treatment technologies for the enhancement of surface hardness and wear resistance of CrAlN/SKD61, simultaneously.

• 한국식품과학회지
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• 제47권1호
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• pp.13-19
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• 2015

원산지별 건고추(중국산, 베트남, 국산)의 전자빔 조사처리에 따른 품질변화를 알아보고자 미생물학적 및 이화학적 품질 특성을 확인하였다. 비조사처리 건고추의 미생물 오염농도는 총 세균, 효모 및 곰팡이가 $10^6-10^7CFU/g$이 확인되었고, 대장균군은 베트남산에서만 $10^3CFU/g$이 확인되었다. 그러나 전자빔 조사처리에 의해 총 세균, 효모 및 곰팡이는 약 2-4 log cycle 정도 감소되었으며, 대장균군은 1 kGy 이상에서 검출되지 않았다. 또한 원산지에 따른 전자빔 조사처리 된 건고추의 수분, pH는 조사선량에 따른 유의적인 차이가 나타나지 않았으며, 환원당 함량은 1 kGy에서 다소 증가하는 경향이 있으나 유의적인 차이는 미미한 것으로 나타났다. 고추의 주요 매운맛 성분인 capsaicinoid함량은 중 국산(19.21 mg%), 베트남산(214.36 mg%), 국내산(7.28 mg%)으로 베트남산이 가장 높게 나타났으며, 조사선량이 증가할수록 그 함량은 감소하였다. 그러나 전자빔 조사처리 고추의 L 값 및 a 값은 유의적인 차이가 나타나지 않았으나, b 값은 조사선량이 증가할수록 증가하였으며, capsanthin 함량 및 ASTA values는 선량에 의한 영향보다 원산지에 의해 더 큰 영향을 받는 것으로 나타났다. 따라서 본 연구에서는 미생물을 효과적으로 살균하고 품질변화를 최소화하는 고추의 위생적 살균방법으로 전자빔 살균기술의 타당성을 확인하였다.

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.70-77
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• 2024

A low energy ion irradiation system based on the deuterium arc ion source with a high perveance of 1 µP for a single extraction aperture has been successfully developed for the investigation of ion irradiation on plasma-facing components including the first mirror of plasma optical diagnostics system. Under the optimum operating condition for mirror testing, the ion source has a beam energy of 200 eV and a current density of 3.7 mA/cm². The ion source comprises a magnetic cusp-type plasma source, an extraction system, a target system with a Faraday cup, and a power supply control system to ensure stable long time operation. Operation parameters of plasma source such as pressure, filament current, and arc power with D₂ discharge gas were optimized for beam extraction by measuring plasma parameters with a Langmuir probe. The diode electrode extraction system was designed by IGUN simulation to optimize for 1 µP perveance. It was successfully demonstrated that the ion beam current of ~4 mA can be extracted through the 10 mm aperture from the developed ion source. The target system with the Faraday cup is also developed to measure the beam current. With the assistance of the power control system, ion beams are extracted while maintaining a consistent arc power for more than 10 min of continuous operation.

• 방사선산업학회지
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• 제6권3호
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• pp.267-272
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• 2012

This study evaluated the change in anti-allergy activity of ${\beta}-glucan$ by electron beam irradiation. ${\beta}-Glucan$ was irradiated at dose of 50 kGy and then orally pre-treated with electron beam irradiated and non irradiated ${\beta}-Glucan$ for 7 days. After pre-treatment, allergy was induced by injection of ovalbumin (OVA). Serum total immunoglobulin E (IgE) and OVA-specific IgE levels in the allergic mice was significantly increased but the mice pre-treated 50 kGy electron beam irradiated ${\beta}-glucan$ was significantly decreased the levels of total IgE and OVA-specific IgE, respectively. Moreover, cytokine production (interleukin-4) was also decreased in the 50 kGy electron beam irradiated ${\beta}-Glucan$ pre-treated mice. These results indicate that pre-treatment of 50 kGy electron beam irradiated ${\beta}-glucan$ may elevate the anti-allergy activity. Therefore, electron beam-irradiated ${\beta}-glucan$ could be used for nutraceutical foods in food industry.

• E2M - 전기 전자와 첨단 소재
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• 제7권2호
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• pp.100-106
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• 1994

A bilayer film consisting of a layer of a-Se$_{75}$ Ge$_{25}$ with a surface layer of silver -100[.angs.] thick and a monolayer film of a-Se$_{75}$ Ge$_{25}$ are irradiated with 9[keV] Ga$^{+}$ ion beam. The Ga$^{+}$ ion (10$^{16}$ [ions/cm$^{2}$] exposed a-Se$_{75}$ Ge$_{25}$ and Ag/a-Se$_{75}$ Ge$_{25}$ thin films show an increase in optical absorption, and the absorption edge on irradiation with shifts toward longer wavelength. The shift toward longer wavelength called a "darkening effect" is observed also in film exposure to optical radiation(4.5*10$^{20}$ [photons/cm$^{2}$]). The 0.3[eV] edge shift for ion irradiation films is about twice to that obtained on irradiation with photons. These large changes are primarily due to structural changes, which lead to high etch selectivity and high sensitivity.

• 식품과학과 산업
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• 제53권3호
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• pp.264-276
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• 2020

Ionizing radiation is one of the efficient non-thermal pasteurization methods. The US Food and Drug Administration (FDA) allows the use of ionizing radiation to a dose up to 10 kGy for controlling foodborne pathogens and extending the self-life of foods. Recently X-rays, generated on absorption of high energy electrons in an appropriate metal target, have been used commercially for sterilization purposes. X-rays have the advantages of higher penetration power than E-beams and absence of harmful radioactive sources, such as Cobalt-60 or Cesium-137 associated with gamma-rays. That is why it has continued to receive attention as an attractive alternative to gamma-ray or E-beam irradiation. In this article, the potential of X-ray irradiation for controlling foodborne pathogens in various food products and necessary pre-requisite knowledge for the introduction of X-ray irradiation to the Korean food industry will be provided.

• 한국식품영양과학회지
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• 제37권2호
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• pp.195-202
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• 2008

신고배(Pyrus pyrifolia cv. Niitaka)의 휘발성 향기성분에 전자선 조사의 영향과 전자선 조사 후 저장기간에 따른 휘발성 향기성분의 변화를 확인하기 위하여 본 연구를 수행하였다. SDE 추출방법과 GC/MS 분석에 의하여 선량에 따른 신고배의 휘발성 향기성분을 분석하였다. 비조사 신고배와 전자선 0.25, 0.5, 1 그리고 3 kGy로 조사된 신고배에서 각각 46, 45, 44, 48 그리고 51종의 화합물을 동정하였다. 신고배의 주요 휘발성 향기성분으로는 $C_6$ 화합물인 hexanal, n-hexanol, (E)-2-hexenal이 분리 동정되었다. $4^{\circ}C$에서 30일 저장 후 신고배의 휘발성 향기성분의 조성은 유사하였으며, 저장기간 동안 크게 변화가 없었다. 소비자 수용성에 기여하는 휘발성 향기성분에 대하여 전자선 조사는 휘발성 향기성분의 변화에 크게 영향을 미치지 않는 것으로 판단되었다. 관능평가 실시 결과, 1 kGy 이하의 저선량으로 전자선 조사된 배의 기호도가 대조군보다 오히려 약간 높은 것으로 나타났으며 유의적인 차이는 없었다. 위의 결과를 토대로 신고배의 전자선 조사기술을 적용하기 위해서는 다양한 실험방법을 통한 지속적인 연구가 필요할 것으로 사료된다.

• 한국초전도ㆍ저온공학회논문지
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• 제18권4호
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• pp.15-20
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• 2016

The effects of electron beam (EB) irradiation on the superconducting critical temperature ($T_c$) and critical current density ($J_c$) of YBCO films were studied. The YBCO thin films were irradiated using a KAERI EB accelerator with an energy of 0.2 MeV and a dose of $10^{15}-10^{16}e/cm^2$. A small $T_c$ decrease and a broad superconducting transition were observed as the EB dose increased. The value of $J_cs$ (at 20 K, 50 K and 70 K) increased at doses of $7.5{\times}10^{15}$ and $2.2{\times}10^{16}e/cm^2$. However, $J_cs$ decreased as the dose increased further. The X-ray diffraction (XRD) analysis showed that the c axis of YBCO was elongated and the full width at half maximum (FWHM) increased as the dose increased, which is strong evidence of the atomic displacement by EB irradiation. The transmission electron microscopy (TEM) showed that the amorphous layer formed in the vicinity of the surfaces of the irradiated films. The amorphous phase was often present as an isolated form in the interior of the films. In addition to the formation of the amorphous phase, many striations running along the a-b direction of YBCO were observed. The high magnification lattice image showed that the striations were stacking faults. The enhancement of $J_c$ by EB irradiation is likely to be due to the lattice distortion and the formation of defects such as vacancies and stacking faults. The decrease in $J_c$ at a high EB dose is attributed to the extension of the amorphous region of a non-superconducting phase.

• Transactions on Electrical and Electronic Materials
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• 제18권4호
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• pp.217-220
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• 2017

We deposited transparent conductive ZTO/Ag/ZTO trilayer thin films on glass substrates through magnetron sputtering, and then conducted intense electron beam irradiation on their surfaces to investigate the effects of electron irradiation on the structural, optical, and electrical properties of these films. After deposition, we electron irradiated the ZTO/Ag/ZTO films for 10 min at electron energies of 300, 500, and 700 eV. The films that were electron irradiated at 700 eV showed a higher optical transmittance (84.2%) in the visible wavelength region and a lower resistivity ($7.2{\times}10^{-5}{\Omega}cm$) compared with the other films. The figure of merit revealed that the ZTO/Ag/ZTO films that were electron irradiated at 700 eV had a higher optical and electrical performance than the other films prepared in this study.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.388-388
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• 2011

Graphene, with its unique physical and structural properties, has recently become a proving ground for various physical phenomena, and is a promising candidate for a variety of electronic device and flexible display applications. The physical properties of graphene depend directly on the thickness. These properties lead to the possibility of its application in high-performance transparent conducting films (TCFs). Compared to indium tin oxide (ITO) electrodes, which have a typical sheet resistance of ~60 ${\Omega}/sq$ and ~85% transmittance in the visible range, the chemical vapor deposition (CVD) synthesized graphene electrodes have a higher transmittance in the visible to IR region and are more robust under bending. Nevertheless, the lowest sheet resistance of the currently available CVD graphene electrodes is higher than that of ITO. Here, we report an ingenious strategy, irradiation of MeV electron beam (e-beam) at room temperature under ambient condition,for obtaining size-homogeneous gold nanoparticle decorated on graphene. The nano-particlization promoted by MeV e-beam irradiation was investigated by transmission electron microscopy, electron energy loss spectroscopy elemental mapping, and energy dispersive X-ray spectroscopy. These results clearly revealed that gold nanoparticle with 10~15 nm in mean size were decorated along the surface of the graphene after 1.0 MeV-e-beam irradiation. The fabrication high-performance TCF with optimized doping condition showed a sheet resistance of ~150 ${\Omega}/sq$ at 94% transmittance. A chemical transformation and charge transfer for the metal gold nanoparticle were systematically explored by X-ray photoelectron spectroscopy and Raman spectroscopy. This approach advances the numerous applications of graphene films as transparent conducting electrodes.