• 산업식품공학
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• 제15권1호
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• pp.28-33
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• 2011

UV-C와 -B type의 lamp를 이용한 혼합 자외선(UV)조사의 조사시간, 조사온도 및 광 촉매제인 $H_2O_2$의 분사농도변화를 이용하여 감귤껍질에 부착되어있는 농약을 제거하기 위한 공정의 최적화를 이루고자 하였다. Chloropyrifos에 대한 독립변수들의 영향력은 조사온도가 가장 컸으며 그 다음 조사시간, $H_2O_2$ 분사농도 순 이었다. Methidathion은 조사시간이 가장 컸으며 조사온도, $H_2O_2$ 분사농도 순으로 나타났다. EPN은 조사온도와 조사시간이 비슷하게 나타났고 $H_2O_2$ 분사농도가 가장 작았다. UV감귤껍질의 농약 잔존량이 가장 작게 나타난 처리조건으로 chloropyrifos와 EPN에 대한 최적조건으로는 조사시간 60분, 조사온도 $45^{\circ}C$, $H_2O_2$ 분사농도 1000 ppm으로 나타났다. 반면에 methidathion의 경우에는 최적조건으로는 조사시간 60분, 조사온도 $40^{\circ}C$, $H_2O_2$ 분사농도 1000 ppm으로 나타났다. 최적공정조건에서 chloropyrifos, methidathion 및 EPN의 잔존 량은 조사 전의 각각 46, 49 및 28% 수준이었다.

• Transactions on Electrical and Electronic Materials
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• 제9권5호
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• pp.198-201
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• 2008

The electro-optical (EO) characteristics of the one-side rubbing twisted nematic (TN) - liquid crystal display (LCD) on the polyimide (PI) surface with one-side ion beam (IB) irradiation were successfully studied. The good LC alignment for the one-side rubbing TN-LCD on the PI surface with one-side IB irradiation was observed. The suitable transmittance-voltage curves for the one-side rubbing TN-LCD on the PI surface with one-side IB irradiation were measured. Also, the good response time characteristics of the one-side rubbing TN-LCD on the PI surface with one-side IB irradiation were measured. The fast response time can be achieved for the one-side rubbing TN-LCD on the PI surface with one-side IB irradiation.

• 한국초전도ㆍ저온공학회논문지
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• 제24권1호
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• pp.18-22
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• 2022

The effect of electron beam (EB) irradiation on superconducting properties and microstructures of MgB₂ bulk superconductors were investigated. At E-beam doses of 1×10¹⁶ e/cm² and 1×10¹⁷ e/cm², the effect of irradiation on a superconducting transition temperature (T_c) of MgB₂ was weak. As a dose increases to 5×10¹⁷ e/cm², T_c decreases by 0.5 K. The critical current density (J_c) measured at 4.2 K and 20 K, and 0 T - 5 T increases slightly as exposure time increases. X-ray diffraction for the irradiation surface of MgB₂ shows that the diffraction intensity of (hkl) peaks decreases proportionally as the exposure time increases. This indicates that the crystallinity of MgB₂ was degraded by irradiation. TEM investigation for the irradiated sample showed distorted lattice structure, which is consistent with the XRD results. The J_c increase and T_c reduction of MgB₂ by irradiation are believed to be caused by the lattice distortion.

• Nuclear Engineering and Technology
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• 제54권8호
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• pp.3176-3180
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• 2022

A gamma irradiator is a well-developed installation for gamma radiation sterilization. A "shuffle-dwell" mode is preferable for high dose applications. A novel configuration of a shuffle-dwell gamma irradiator is proposed to increase energy utilization and throughput, which would result in higher profitability. While the minimum distance between any irradiation position and each source pencil, the minimum distance between the neighboring irradiation positions and the size of source pencils are kept the same as the current configuration, the irradiation positions and source pencils are rearranged based on the fact that radiation is emitted in an isotropic fashion. The computational results suggest that the proposed configuration requires an 8.7% smaller area and exposes the product to 11.8% more gamma radiation in a 10.7% shorter irradiation time. In other words, the proposed configuration needs a smaller area and shorter irradiation time to have a better performance compared to the current shuffle-dwell gamma irradiator. Note that the claim is based primarily on an analytical calculation. Experimental and manufacturing among other practical considerations will be taken into account in the future work to exhaustively evaluate the performance of the proposed configuration and to compare it with that of the traditional configuration.

• 대한가정학회지
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• 제30권4호
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• pp.77-88
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• 1992

To investigate the oxidative stabilities of the ${\gamma}$-ray irradiated soybean during storage and heating and some physico-chemical characteristics of soybean and the extracted soybean oil (SBO) with/without the ${\gamma}$-ray irradiation were determined. The ${\gamma}$-ray level use in irradiation for soybean were 2.5, 5.0 and 10.0 KGY respectively and Acid Value, Peroxide Value, Conjugated Diene Value, Composed Fatty Acids amounts, and Trans Fatty Acid occurrence were determined for all samples, which were incubated at 45$\pm$1$^{\circ}C$ for 25 days heated at 180$\pm$1$^{\circ}C$ for 30 hours. And these values of the ${\gamma}$-ray treated samples were compared to those of nontreated samples. The results were obtained as follows : 1. According to the increased level of the ${\gamma}$-ray irradiation, there was little difference in Dielectric Constant, Viscosity, and the Induction Period by Rancimat. But, in case of 5.0 KGY, oxidative stability was increased more twice than that of non-irradiation. In the quantity of fatty Acids composition of the extracted soybean oil irradiated with 10.0 KGY, palmitic, oleic and linoleic acids were less increased thanb those of non-irradiation, while stearic, linolenic acids were decreased. In the case of 2.5 KGY irradiation, stearic and oleic acids were increased. 2. The Acid Value of SBO according to the ${\gamma}$-ray irradiation level was almost not change, but was 0.1 lower than that of non-irradiation during incubation (45$\pm$1$^{\circ}C$). The Peroxide Value of SBO with the ${\gamma}$-ray irradiation, was very lower than that of non-irradiation, but its effect on oxidative stability was better of SBO treated with 5.0 KGY and 10.0 KGY. In the Fatty Acids composition of SBO, palmitic, stearic, oleic acids were increased, while linoleic, linolenic acids were decreased during incubation(45$\pm$1$^{\circ}C$). This tendency was more obvious due to the ${\gamma}$-ray level. While heating(180$\pm$1$^{\circ}C$), the Acid Value of SBO treated with the ${\gamma}$-ray irradiation was decreased, the Acid Value of SBO irradiated with 2.5 KGY was the lowest. Also the peroxide Values of SBO treated with 5.0 KGY, 10.0 KGY were very lower than that of non-irradiation. Conjugated Diene Value of SBO was almost unchanged according to the ${\gamma}$-level and heating time. 3. When the methyl linoleate was irradiated with the ${\gamma}$-ray, the Trans Fatty Acid was little produced. In case of SBO with non-irradiation, the trans C18:1 was occured about 6.5~7.9%, but trans C18:2 and C18:3 were not shown, while SBO irradiated with the ${\gamma}$-ray 2.5, 5.0, 10.0 KGY, trans C18:3 and C18:2 amount in SBO were increased according to heating time, but trans C18:3 was little occured. As these results, the effects of the ${\gamma}$-ray irradiation to oil containing food were to cut down the energy for food storage and to increase oxdative stability during storge. And also it was shown to be the best that 10.0 KGY of the ${\gamma}$-ray irradiation would be applied to soybean.

• 대한수의학회지
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• 제34권4호
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• pp.665-678
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• 1994

This study was undertaken to investigate histological changes according to the radiosensitivity in the spermatogenic cells in Korean native pheasants. During spermatogenetic period, testes wete collected from male adult Korean native pheasant and they were used as experimental and control birds. The experimental group was divided into a single-dose whole body irradiation group(400, 600, 800 and 1000 rads) and a split-dose whole body irradiation groups(400/2, 600/2, 800/2 and 1000/2 rads). A Henseky's $^{60}Co$ ${\gamma}$-radiotherapy machine was used for this experiment and the dose rate of $^{60}Co$ ${\gamma}$-ray was 104 rads/min. The experimental birds were sacrificed at 24 and 72 hrs after irradiation and the control pheasants were sacrificed at the same time. General histological changes of seminiferous epithelial cells were observed by hematoxylin-eosin stain with light microscope. The results obtained are summarized as follows ; 1. In the single-dose and the split-dose irradiation groups, the average diameter of the seminiferous tubule was decreased compared with control group. 2. Seminiferous epithelial cells were more severely damaged after 72 hrs than after 24 hrs of single-dose irradiation of 400, 600 and 800 rads but the difference of cell injury was almost not observable with the elapsed time in the group of the single-dose irradiation of 1000 rads. 3. The damage of spermatogenic cells were more severe after 24 hrs than after 72 hrs of the split-dose irradiation of 400 rads but the split-dose irradiation of 600, 800 and 1000 rads were more severe after 72 hrs than after 24 hrs.

• 펄프종이기술
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• 제47권5호
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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.

• Imaging Science in Dentistry
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• 제38권4호
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• pp.195-202
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• 2008

Purpose : To characterize the effects of 2-deoxy-D-glucose (2-DG) and quercetin (QCT) on gene expression of osteonectin (ON) and osteopontin (OP) in irradiated MC3T3-El cells. Materials and Methods : When MC3T3-El osteoblastic cells had reached 70-80% confluence, cultures were transferred to a differentiating medium supplemented with 5 mM 2-DG or 10 ${\mu}M$ QCT and then irradiated with 2, 4, 6, and 8 Gy. At various times after irradiation, the cells were analyzed for the expression of bone mineralization genes such as ON and OP. Results : The mRNA expression of both ON and OP was increased according to the culture time in the differentiation medium, and the increase of the genes peaked at 14 days after the differentiation induction. In the case of OP, the increase of mRNA expression was maintained to 28 days after the differentiation, while the mRNA level of ON was reduced to the basal level at the same time. Irradiation adding 2-DG showed a significant peak value in the expression pattern of ON at 4 Gy 7 days after irradiation. Irradiation adding QCT increased the mRNA expression of ON and OP in a dose-dependant manner, but irradiation adding 2-DG did not show any differences between the control and experiments 14 days after irradiation. Irradiation adding QCT increased significantly the expression patterns of ON 21 days after irradiation. Conclusion : The results showed that QCT acted as a radiosensitizer in the gene expression of ON and OP during differentiation of the late stage of irradiated MC3T3-E1 osteoblastic cells in vitro. (Korean J Oral Maxillofac Radiol 2008; 38: 195-202)

• Toxicological Research
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• 제15권1호
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• pp.35-38
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• 1999

RNA synthesis rate was measured at different time points after UV irradiation in various xeroderma pigmentosum (XP) cells including complementation groups F and G. The RNA synthesis was assayed by measuring 3H-uridine incorporation. In normal cells, recovery of RNA synthesis was initiated at about 6 hr ager UV irradiation and reached to the same level as in unirradiated cells at 24hr after UV irradiation. By contrast, no such recovery was observed in group F,G XP cells.

• 한국전기전자재료학회논문지
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• 제19권3호
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• pp.216-221
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• 2006

Lifetime control technique by proton implantation has become an useful tool for production of modern power devices. In this work, punch-through type diodes were irradiated with protons for the high speed power diode fabrication. Proton irradiation which was capable of controlling carrier's lifetime locally was carried out at the various energy and dose conditions. Characterization of the device was performed by current-voltage, capacitance-voltage and reverse recovery time measurement. We obtained enhanced reverse recovery time characteristics which was about $45\;\%$ of original device reverse recovery time and about $73\;\%$ of electron irradiated device reverse recovery time. The measurement results showed that proton irradiation technique was able to effectively reduce minority carrier lifetime without degrading the other characteristics.