• Title/Summary/Keyword: Electron beam treatment

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Fabrication of carbon nanostructures using electron beam lithography and pyrolysis for biosensing applications (전자빔 리소그래피와 열처리를 이용한 탄소 나노구조물의 제작 및 바이오센싱 응용연구)

  • Lee, Jung-A;Lee, Kwang-Cheol;Park, Se-Il;Lee, Seung-S.
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.1727-1732
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    • 2008
  • We present a facile, yet versatile carbon nanofabrication method using electron beam lithography and resist pyrolysis. Various resist nanopatterns were fabricated using a negative electron beam resist, SAL-601, and were then subjected to heat treatment in an inert atmosphere to obtain carbon nanopatterns. Suspended carbon nanostructures were fabricated by wet-etching of an underlying sacrificial oxide layer. Free-standing carbon nanostructures, which contain 122 nm-wide, 15 nm-thick, and 2 ${\mu}m$-long nanobridges, were fabricated by resist pyrolysis and nanomachining processes. Electron beam exposure dose effects on resist thickness and pattern widening were studied. The thickness of the carbon nanostructures was thinned down by etching with oxygen plasma. An electrical biosensor utilizing carbon nanostructures as a conducting channel was studied. Conductance modulations of the carbon device due to streptavidin-biotin binding and pH variations were observed.

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Molecular Weight Control of Chitosan Using Gamma Ray and Electron Beam Irradiation

  • Kim, Hyun Bin;Lee, Young Joo;Oh, Seung Hwan;Kang, Phil Hyun;Jeun, Joon Pyo
    • Journal of Radiation Industry
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    • v.7 no.1
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    • pp.51-54
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    • 2013
  • Chitosan is a useful natural polymer material in many application fields such as biomaterials, water-treatment, agriculture, medication, and food science. However, the poor solubility limits its application. In this study, the effects of radiation on chitosan were investigated using gamma ray and electron beam irradiation. The chemical structure and molecular weight analysis show similar degradation effects of chitosan powder in both gamma ray and electron beam irradiation. However, the radiation irradiated chitosan in $H_2O$ has a lower molecular weight, since the hydroxyl radicals attack the glycosidic bonds. This effect is more clearly shown in the electron beam irradiation results.

Comparison of Irradiation Effect of Different Radiation Types on Decontamination of Microorganisms in Red Pepper Powder (고춧가루 오염 미생물의 제어에서 방사선종별 조사 효과)

  • Park, Kyung-Sook
    • 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.

Development of Auto-hydrolysis Method for Preparing Cotton Linter Regenerated Fibers of Textile Fabrics (방직용 재생펄프 제조를 위한 면 린터의 자기가수분해 공정 개발)

  • Sohn, Ha Neul;Park, Hee Jung;Seo, Yung Bum
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.47 no.6
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    • pp.81-88
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    • 2015
  • The molecular weight (MW) and crystallinity of cotton linter need to be controlled to be dissolved well in N-methylmorpholine N-oxide (NMMO) solvent for manufacturing regenerated fibers of clothing fabrics. Electron beam irradiation or sulfuric acid pre-treatment followed by alkaline peroxide bleaching has been used to control MW effectively and to improve brightness of cotton linter. Auto-hydrolysis of cotton linter without electron beam irradiation or chemical pre-treatment was found to be effective as an alternative pre-treatment method. Removal of metal ions, that hampered dissolution of cotton linter by NMMO, was also investigated when the auto-hydrolysis was accompanied with ionic polymers and chelating agent.

Novel reforming of pyrolized fuel oil by electron beam radiation for pitch production

  • Jung, Jin-Young;Park, Mi-Seon;Kim, Min Il;Lee, Young-Seak
    • Carbon letters
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    • v.15 no.4
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    • pp.262-267
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    • 2014
  • Pyrolized fuel oil (PFO) was reformed by novel electron beam (E-beam) radiation, and the elemental composition, chemical bonds, average molecular weight, solubility, softening point, yields, and density of the modified patches were characterized. These properties of modified pitch were dependent on the reforming method (heat or E-beam radiation treatment) and absorbed dose. Aromaticity ($F_a$), average molecular weight, solubility, softening point, and density increased in proportion to the absorbed dose of E-beam radiation, with the exception of the highest absorbed dose, due to modification by free radical polymerization and the powerful energy intensity of E-beam treatment. The H/C ratio and yield exhibited the opposite trend for the same reason. These results indicate that novel E-beam radiation reforming is suitable for the preparation of aromatic pitch with a high ${\beta}$-resin content.

Dosimetry for Total Skin Electron Beam Therapy in Skin Cancer (피부암치료를 위한 전자선 전신피부 치료방법과 선량분포 측정)

  • Chu, Sung-Sil;Loh, John-Jk;Kim, Gwi-Eon
    • Radiation Oncology Journal
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    • v.10 no.1
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    • pp.107-113
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    • 1992
  • Increasing frequency of skin cancer, mycosis fungoides, Kaposi's sarcoma etc, it need to treatment dose planning for total skin electron beam (TSEB) therapy. Appropriate treatment planning for TSEB therapy is needed to give homogeneous dose distribution throughout the entire skin surface. The energy of 6 MeV electron from the 18 MeV medical linear accelerator was adapted for superficial total skin electron beam therapy. The energy of the electron beam was reduced to 4.2 MeV by a $0.5\;cm\times90\;cm{\times}180\;cm$ acryl screen placed in a feet front of the patient. Six dual field beam was adapted for total skin irradiation to encompass the entire body surface from head to toe simultaneously. The patients were treated behind the acryl screen plate acted as a beam scatterer and contained a parallel-plate shallow ion chamber for dosimetry and beam monitoring. During treatment, the patient was placed in six different positions due to be homogeneous dose distribution for whole skin around the body. One treatment session delivered 400 cGy to the entire skin surface and patients were treated twice a week for eight consecutive weeks, which is equivalent to TDF value 57. instrumentation and techniques developed in determining the depth dose, dose distribution and bremsstrahlung dose are discussed.

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Chemical and Thermal Characterizations of Electron Beam Irradiated Jute Fibers (전자빔 조사된 황마섬유의 화학적 및 열적 특성분석)

  • Ji, Sang Gyu;Cho, Donghwan;Lee, Byung Cheol
    • Journal of Adhesion and Interface
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    • v.11 no.4
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    • pp.162-167
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    • 2010
  • In the present work, the effect of electron beam irradiation on the chemical and thermal characteristics of cellulose-based jute fibers was explored by means of chemical analysis, electron spin resonance analysis, ATR-FTIR spectroscopy, thermogravimetric analysis and thermomechanical analysis. Jute fiber bundles were uniformly irradiated in the range of 2~100 kGy by a continuous method using a conveyor cartin an electron beam tunnel. Electron beam treatment, which is a physical approach to change the surfaces, more or less changed the chemical composition of jute fibers. It was also found that the radicals on the jute fibers can be increasingly formed with increasing electron beam intensity. However, the electron beam irradiation did not change significantly the chemical functional groups existing on the jute fiber surfaces. The electron beam irradiation influenced the thermal stability and thermal shrinkage/expansion behavior and the behavior depended on the electron beam intensity.

Effect of Electron Beam Irradiation on the Properties of Softwood Unbleached Kraft Pulp (전자선 전처리에 따른 침엽수 미표백 크라프트 펄프의 특성평가)

  • Kim, Eun Hea;Lee, Ji Young;Jeun, Joon Pyo;Kim, Sun Young;Kim, Chul Hwan;Park, Jong Hye
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.47 no.5
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    • pp.68-73
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    • 2015
  • Electron beam irradiation is also an eco-friendly treatment compared to other physical and chemical treatments. In this study, we attempted to evaluate the possibilities of energy savings by applying electron beam irradiation to the refining process. After softwood unbleached kraft pulp (UKP) was irradiated with electron beams at 50 and 100 kGy, it was beaten in a laboratory beater, and then its freeness and fiber properties were analyzed. The physical properties of their fiber handsheet were also and measured. As the irradiation dose of the electron beam and the beating time increased, lower freeness and fiber lengths of the UKP were observed. Handsheets made from UKP that was irradiated by electron beam and beaten showed a reciprocal relationship with the irradiation dose of the electron beam, in particular, the strength of the handsheets decreased dramatically at 100 kGy of irradiation. Therefore, it was confirmed that electron beam irradiation is effective in reducing the beating time or beating energy. But the irradiation dose must be controlled under 50 kGy to minimize the loss of paper strength.

Improvement of the Biodegradability of Polyvinyl Alcohol by Radiation Treatment (방사선 처리에 의한 폴리비닐 알콜의 생분해도 개선)

  • Jung, Jinho;Park, Nam-Young;Jo, Hun-Je;Lee, Sun-Mi;Kim, Jeong-Gyu
    • Journal of Korean Society on Water Environment
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    • v.20 no.3
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    • pp.241-244
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    • 2004
  • Radiation treatment with gamma-rays and electron-beams was used to remove polyvinyl alcohol(PVA), one of the main components of dyeing wastewater. PVA was effectively decomposed by radiation treatment, thus the removal was near 100 % at an initial PVA concentration of 44 mg/L. However, total organic carbon(TOC) removal was less than 5 % due to lower transformation of PVA to $CO_2$. This directly indicates the radiation treatment alone is not appropriate for the complete decomposition of PVA. In this sense, the improvement of biodegradability($BOD_5/COD$) of PVA by radiation treatment was studied. Both gamma-ray and electron-beam treatments significantly increased the biodegradability of PVA by transforming non-biodegradable PVA to biodegradable by-products. This suggests radiation treatment, especially electron-beam treatment that showed better improvement of biodegradability, can be used as a pre-treatment of biological degradation process of PVA.

A Study on the Dosimetry of the Total Skin Electron Beam Therapy in Cutaneous T-Cell Lymphoma (피부 T 세포림프종의 전 피부 전자선 치료를 위한 dosimetry 연구)

  • 신교철;윤형근
    • Progress in Medical Physics
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    • v.7 no.2
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    • pp.57-65
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    • 1996
  • Total Skin Electron Beam Therapy (TSEBT) is one of the most effective treatment methods for superficially disseminated skin cancer or cutaneous T-cell lymphoma. We have treated a patient with cutaneous T-cell lymphoma. We have used Stanford technique using six dual field. The nominal energy of electron beam was 4MeV. SSD was 390cm and the gantry angles of dual fields were 76$^{\circ}$ and 104$^{\circ}$. The dose profiles of single field and dual fields were measured with films and a Farmer type ion chamber. The field uniformity was 10% over the patient's surface. During treatment, the patient was placed in six different positions for homogenous dose distribution over the body surface. The areas not directly exposed to the path of the electron beam (soles of feet, perineum and vertex of scalp) were boosted with 7MeV electron beam. During the treatment, lens, fingernails and toenails were shielded.

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