• 방사선산업학회지
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• 제7권2_3호
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• pp.167-170
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• 2013

Lignin can be a valuable natural chemical resource. Structurally, lignin is a three-dimensional polymer made up of condensed C-C bonds and some ether linkages, most of which are not readily degraded. In this study, lignin carbonization under various electron beam pretreatment conditions was characterized through a thermogravimetric analysis (TGA), X-ray diffraction (XRD) and Raman spectroscopy. Lignin stabilization was controlled by various doses of electron beam irradiation corresponding to 50, 100, 200, 500 and 1,000 kGy; the carbonization process was performed under a nitrogen gas atmosphere at $1000^{\circ}C$ for 1 h. The TGA results showed that a 1,000 kGy lignin dose increased the residue weight from 39.96% to 45.23%, compared to non-irradiated lignin. This observation is in agreement with the XRD and Raman spectroscopy results, in which the two theta degrees and the degree of crystallization were improved by increasing the electron beam irradiation.

• Journal of Radiation Protection and Research
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• 제40권2호
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• pp.87-91
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• 2015

We have employed X-ray photoelectron spectroscopy (XPS) technique to examine the combined effects of low-energy electron (LEE) irradiation and $Fe^{3+}$ ion on DNA damage. pBR322 plasmid DNA extracted from E. coli ER2420 was used for preparing DNA-$Fe^{3+}$ sample. The C1s XPS spectra were scanned for LEE-irradiated and LEE-unirradiated samples and then curve-fitted. For the samples with LEE irradiation only or with Fe ion only, no significant changes from pure DNA samples were observed - a single effect of either $Fe^{3+}$ ion or LEE irradiation did not cause a significant damage. However, when these two components were combined, the DNA damage was increased quite significantly, compared to the sum of DNA damages caused by $Fe^{3+}$ ion and by LEE irradiation independently. This observation is consistent with our previous results [Radiat. Res. 177, 775 (2012)] which was done using gel-electrophoresis technique. Partial interpretation of the observed spectrum peaks was also attempted.

• Journal of Applied Biological Chemistry
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• 제57권2호
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• pp.141-144
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• 2014

국가간 농산물의 수출입 검역시 새로운 기술로 인정받고 있는 전자빔 조사시 귤가루깍지벌레와 복숭아혹진딧물의 방제효과를 조사한 결과, 저선량의 전자선 조사(30, 60, 90 및 120 Gy)는 복숭아혹진딧물과 귤가루깍지벌레의 직접적인 방제효과는 나타나지 않았으나, 발육 및 생식 억제에 크게 영향을 끼쳐 해충에 대한 불활성화 효과를 나타내었다. 이 같은 결과는 국가간 농산물 수출입 검역현장에서 전자선 조사기술이 메틸브로마이드와 같은 화학적 병해충 방제를 대체할 새로운 가능성을 확인해 주는 결과이다.

• 분석과학
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• 제19권4호
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• pp.333-341
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• 2006

PVP-protected Ag, Pd and $Pt_{50}-Ru_{50}$ colloids were prepared independently by using ${\gamma}$-irradiation and electron beam (EB) at ambient temperature. UV-visible spectra of these colloids show the characteristic bands of surface resonance and give evidence for the formation of nanoparticles. Transmission electron microscopy (TEM) experiments were used to know the morphology of nanoparticles prepared by ${\gamma}$-irradiation and EB. The size of Ag, Pd, and $Pt_{50}-Ru_{50}$ nanoparticles prepared by ${\gamma}$-irradiation was ca. 13, 2-3, 15 nm, respectively. While, the size of Ag, Pd, and $Pt_{50}-Ru_{50}$ nanoparticles prepared by EB was ca. 10, 6, and 1-3 nm, respectively. Cyclic voltamograms (CV) were recorded for the Au electrodes immobilized with these nanoparticles. CVs indicated the modifications in the surface as a result of immobilization.

• 접착 및 계면
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• 제11권4호
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• pp.162-167
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• 2010

본 연구에서는 셀룰로스계 섬유인 황마(jute)의 화학적 특성 및 열적 특성에 미치는 전자빔조사의 영향을 원소분석, ESR분석, ATR-FTIR 분광분석, 열중량분석 그리고 열기계분석을 통하여 탐구하였다. 전자빔 조사는 전자빔터널 내에서 콘베이어 카트를 이용한 연속식 방법에 의해 2~100 kGy까지 다양한 세기의 전자빔이 황마섬유다발에 일정하게 행하였다. 전자빔 처리는 황마섬유의 화학조성을 다소 변화시켰으며, 전자빔세기가 커질수록 황마섬유에 형성된 라디칼이 증가하는 것으로 확인되었다. 그러나 전자빔 조사는 황마섬유표면의 화학관능기를 크게 변화시키지 않는 것으로 판단되었다. 또한 전자빔 조사는 황마섬유의 열안정성과 열수축/팽창 거동에 영향을 주었으며, 그 거동은 전자빔세기에 의존하였다.

• 치과방사선
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• 제18권1호
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• pp.31-45
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• 1988

The author studied the histopathologic changes according to a single or a split dose and the time after irradiation on the acinar cells of rat parotid gland. 99 Sprague Dawley rats, weighing about l20gm, were divided into control and 3 experimental groups. In experimental groups, GroupⅠ and Ⅱ were delivered a single dose of l5Gy, 18Gy and Group Ⅲ and Ⅳ were delivered two equal split doses of 9Gy, 10.5Gy for a 4 hours interval, respectively. The experimental groups were delivered by a cobalt-60 teletherapy unit with a dose rate of 222cGy/min, source-skin distance of 50㎝, depth of l㎝ and a field size of l2×5㎝. The animals were sacrificed at 1, 2, 3, 6, 12 hours, 1, 3, 7 days after irradiation and examined by light and electron microscopy. The results were as follows: 1. As the radiation dose increased and the acinar cells delivered a single dose exposure were more damaged, and the change of acinar cells appeared faster than those of a split dose exposure. 2. The histopathologic change of acinar cells appeared at 1 hour after irradiation. The recovery from damaged acinar cells appeared at 1 day after irradiation and there was a tendency that the recovery from damage of a split dose exposure was somewhat later than that of a single dose exposure. 3. Light microscope showed atrophic change of acinar cells and nucleus, degeneration and vesicle formation of cytoplasm, widening of intercellular space and interlobular space. 4. Electron microscope showed loss of nuclear membrane, degeneration of nucleus and nucleoli, clumping of cytoplasm, widening and degeneration of rough endoplasmic reticulum, loss of cristae of mitochondria, lysosome, autophagosome and lipid droplet. 5. Electron microscopically, the change of rough endoplasmic reticulum was the most prominent and this appeared at 1 hour after irradiation as early changes of acinar cells. The nuclear change appeared at 2 hours after irradiation and the loss of cristae of mitochondria was observed at 2 hours after irradiation in all experimental groups.

• 한국식품영양과학회지
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• 제28권2호
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• pp.378-382
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• 1999

The sanitizing effect of irradiation on the fresh vegetable extract juices was investigated. Total bacteria, coliform bacteria and total ascorbic acid were determined during the storage periods at 4oC. Chlorophyll, carotenoid, tannin, electron donating ability and peroxidase activity were determined immediately after irradiation. Results showed that the viable cells were detected below the level of 105 CFU/ml during 12 days with doses of 3 and 5 kGy. Total ascorbic acid and tannin contents increased immediately after irradiation. However, irradiation didn't affect chlorophyll and car otenoid contents, electron donating ability, and peroxidase activity. It was considered that irradiation was effective in sanitizing fresh vegetable extract juices.

• 펄프종이기술
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• 제46권4호
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• pp.37-43
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• 2014

The crystallinity and molecular weight of cotton linter need to be controlled to be more easily dissolved in NMMO during manufacture of clothing fabrics. Electron beam irradiation and sulfuric acid treatment were used as pre-treatment to reduce molecular weight of cotton linter more efficiently, and after the pre-treatment, peroxide bleaching was followed in alkaline condition. After those processes, the crystalline indices of the cotton linters were measured by XRD method, and other properties such as their alpha cellulose contents and degree of polymerization were measured. It was found that the crystallinity index of cotton linter was decreased as the irradiation of electron beam increased while increased as the dose of sulfuric acid increased. These results strongly suggested that electron beam damaged the crystalline structure of the cellulose directly while sulfuric acid dissolved mostly non-crystalline area of the cellulose structure.

• Mass Spectrometry Letters
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• 제5권3호
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• pp.89-93
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• 2014

Lincomycin is one of the major species among the Pharmaceuticals and Personal Care Products (PPCPs) detected from the four major rivers in Korea. The structure characterization was performed of six degradation products of lincomycin formed under the irradiation of electron beam, and the degradation efficiency as a function of the various irradiation dose and sample concentration was investigated. Electron beam (10 MeV, 0.5 mA and 5 kW) experiments for the structural characterization of degradation products that are fortified with lincomycin, were performed at the dose of 10 kGy. The separation of degradation products and lincomycin was carried out using a C18 column ($2.1{\times}100$ mm, $3.5{\mu}m$), using gradient elution with 20 mM ammonium acetate and acetonitrile. The structures of six degradation products of lincomycin were proposed by interpretation of mass spectra and chromatograms by LC-MS/MS. The mass fragmentation pathways of mass spectra in tandem mass spectrometry were also proposed. Experiments were performed of the degradation efficiency as a function of the irradiation dose intensity and the initial concentration of lincomycin in an aqueous environment. In addition, increased degradation efficiency was observed with a higher dose of electron beam and lower concentration.

• 방사선산업학회지
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• 제4권3호
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• pp.259-263
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• 2010

Carbon fibers are used as a reinforcement material in an epoxy matrix in advanced composites due to their high mechanical strength, rigidity and low specific density. An important aspect of the mechanical properties of composites is associated to the adhesion between the surface of the carbon fiber and the epoxy matrix. This paper aimed to evaluate the effects of electron beam irradiation on the physicochemical properties of carbon fibers to obtain better adhesion properties in resultant composite. Chemical structure and surface elements of carbon fiber were determined by FT-IR, elemental analysis and X-ray photoelectron spectroscopy, which indicated that the oxygen content increased significantly with increasing the radiation dose. Thermal stability of the carbon fibers was studied via the thermalgravimetric analysis. Surface morphology of carbon fiber was analyzed by scanning electron microscope. It was found that the degree of surface roughness was increased by electron beam irradiation.