• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.518-521
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• 2004

The degradation characteristics of MgO protective layer and phosphors have been investigated in terms of the ion-induced secondary electron emission coefficient ${\gamma}$ and static margin of discharge voltages, respectively, in this experiment. The ion-induced secondary electron emission coefficients ${\gamma}$ for the degraded MgO protective layer and phosphors have been studied by ${\gamma}$ -focused ion beam system. The energy of Ne+ ions used is from 80 eV to 200 eV in this experiment. The degraded MgO and phosphor layers are found to have higher ${\gamma}$ than that of normal ones without degradations or aged one. Also, the static margin of discharge voltages for test panels with degraded MgO protective layer and phosphors been found to be seriously decreased in comparison with those of normal ones without degradations.

• Journal of Radiation Protection and Research
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• v.36 no.3
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• pp.168-173
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• 2011

This study investigated characteristics of dose distribution at junction field of X-ray and electron beams according to the method for fabricating the insert block on the electron cone. Insert block were fabricated to the divergency cutout block and the straight cutout block. For the 6 MV X-ray and 10 MeV nominal energy of electron beam, we was adjacent to the light field of X-ray and electron beam at a surface of matrix chamber and measured to beam profile of abutted field in the 0, 1, 2, 3 cm measurement depth. As a result, characteristics of dose distribution at junction field, straight block was existent that over dose area exceed the give dose more than 5% and under dose area with a rapid change in dose distribution. However, divergency block had remarkably decreased the over dose area caused by the lateral scattering effects of decrease, and being existed uniformity dose distribution in the junction field. Therefore, divergency block were the benefits of radiation dose delivery, in order to applied the clinical, measurement of electron beams according to the fabrication method of the block should be considered carefully.

• Radiation Oncology Journal
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• v.7 no.2
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• pp.293-297
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• 1989

Electron contamination due to the interaction between radiation beam and material was analyzed for the factors such as source-skin distance (SSD), field size, tray characteristics and position of filter, which can affect the surface dose in Cobalt teletherapy. Surface dose in open beam was more influenced by SSD with increasing field size. Relative surface charge (RSC) increased with the use of tray (solid, circular hole, slotted), compared with open beam, which is thought to be due to increased electron contamination of the tray. To reduce the surface dose, 0.4mm thick Lipowitz metal filter was used. Compared with open beam, RSC decreased by 8.8%, 11.3%, 13.3%, 16.6%, 19.3% and 21.7% for the field size of $5{\times}5$, $10{\times}10$, $15{\times}15$, $20{\times}20$, $25{\times}25$ and $30{\times}30cm^2$, respectively. On the contrary, use of Lipowitz metal filter increased RSC at 60cm or less SSD. Surface dose was effectively reduced with Lpowitz metal filter placed right below solid tray in Cobalt teletherapy.

• Proceedings of the IEEK Conference
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• 2004.06b
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• pp.359-362
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• 2004

Electron beam on high energy acceleration, which travels deeply and sharply through photoresist, became to be used in e-beam lithography apparatus for nano-patterning in due to its high resolution. An advanced electron beam lithography simulation tool is currently undergoing development for nano-patterning. This paper will demonstrate such simulation efforts with experiments at 200 keV e-beam lithography processes on PMMA, ZEP520 of which photoresist parameters and characteristics will be explained with simulation results. Neureuther parameters was extracted from the contrast curve of the resist

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.541-542
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• 2006

In this paper, I propose the field emission tip for the E-beam array system that is made by carbon nanotubes(CNT). CNT is one of the most expected future materials, because of its great mechanical, chemical and electrical characteristics. So CNT can be used for many applications such as electron emitter, sensor, single electron transistor and AFM tip. And CNT will be applied to our E-beam array system as field emission tip so we will improve the system's electrical characteristics.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.890-893
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• 2004

The ultra precision machining in industrial field are increased day by day. The diamond turning has been used generally, but now is faced with limitation of use, because of higher requirement of production field. The electron beam lithography is alternative in machining area as semiconductor production. For EB lithography, 5 axis vacuum stage is required to duplicate small and large patterns on wafer. The stage is composed of 2 rotational axis and 3 translational axis with 5 DC servo motors. The positioning repeatability and resolution of Z axis feed unit are 3.21$\mu$m and 0.5 $\mu$m/step enough to apply to lithography.

• Proceedings of the KIEE Conference
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• 2008.09a
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• pp.235-236
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• 2008

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.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2305-2306
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• 2008

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.

• Proceedings of the KWS Conference
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• 2003.05a
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• pp.87-89
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• 2003

The yield strengths of austenitic stainless steel have been approximately doubled by increasing the nitrogen content. But, the increasing the nitrogen cause of increase the pressure of metal vapor inside the keyhole in electron beam welding. During welding, eruptions of keyhole often occur that cause excessive spatter, concavity, and porocity in the weld zone. Additionally the fast evaporation of nitrogen content cause of decrease the strength of weld zone. Therefore in this paper, we investigated of the weldability of electron beam welding and the change of chemical content after welding for strengthened austenitic stainless steel, measured the deformation scale of both of electron beam and narrow gap TIG and the spike fluctuation in the root.

• Rubber Technology
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• v.5 no.2
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• pp.94-103
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• 2004

The present work describes modification of dual phase filler by electron beam irradiation in presence of multifunctional acrylates like trimethylol propane triacrylate (TMPTA) or silane coupling agent like bis (3-triethoxysilylpropyltetrasulphide) and in-fluence of the modified fillers on the physical properties of styrene-butadiene rubber (SBR) vulcanizates. Modulus at 300 % elongation increases whereas the tensile strength decreases with increase in radiation dose for the dual phase filler loaded styrene-butadiene rubber vulcanizates (SBR). However, modulus and tensile strength significantly increase, which is more, pronounced at higher filler loadings for TMPTA modified dual phase filler loaded SBR. These changes in properties are explained by the equilibrium swelling data and Kraus plot interpreting the polymer-filler interaction. Electron beam modification of the filler results in a reduction of tan ${\delta}$ at $70^{\circ}C$, a parameter for rolling resistance and increase in tan ${\delta}$ at $0^{\circ}C$, a parameter for wet skid resistance of the SBR vulcanizates. Finally, the influence of modified fillers on the properties like abrasion resistance, tear strength and fatigue failure and the improvement in the properties have been explained in terms of polymer-filler interaction.