• 펄프종이기술
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• 제45권6호
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• pp.17-23
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• 2013

The reduction of metal ion from the cotton linter for the preparation of NMMO (N-methylmorpholine N-oxide)-based dissolving pulp was investigated. The NMMO-based dissolving pulp was usually used for the manufacture of high quality fabrics, and need to have high alpha cellulose content and high brightness. NMMO, which is environmentally friendly, and reusable after recovering process, is very sensitive to the metal ions such as Cu, Fe, Mg, and Cr. Electron beam, sulfuric acid, acetic acid, and ozone treatment before bleaching were used and the concentration changes of the metal ions were compared to that of EDTA, a chelating agent. It was found that both acid treatments (sulfuric and acetic acid) were very effective and comparable to EDTA treatment at the same dosage in metal ion reduction, but electron beam and ozone treatment were not. The sulfuric acid treatment turned out to be effective in metal ion reduction, and most inexpensive.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.334-334
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• 2011

We applied N-ion bombardment and heat treatment to the Cu thin films deposited on aluminum oxide layer for the enhancement of adhesion. With e-beam evaporation method. $1,000{\AA}$ thick Cu pre-bombardment layer was deposited on the aluminum oxide surface and then N-ion beam was bombared in order to mix the atoms at the film/substrate interface. Additional $4,000{\AA}$-thick Cu film was the coated. Subsequently, the ion mixide Cu on aluminum oxide was annealed at $200^{\circ}C$ and $300^{\circ}C$ in vacuum.

• 열처리공학회지
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• 제25권6호
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• pp.279-282
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• 2012

$SnO_2$ thin films were prepared on the Si substrate by radio frequency (RF) magnetron sputtering and then surface of the films were irradiated with intense Ar ion beam to investigate the effect of Ar ion irradiation on the properties and hydrogen gas sensitivity of the films. From atomic force microscope observation, it is supposed that intense Ar bombardments promote rough surface and increase gas sensitivity of $SnO_2$ films for hydrogen gas. The films that Ar ion beam irradiated at 6 keV show the higher sensitivity than the films were irradiated at 3 keV and 9 keV. These results suggest that the $SnO_2$ thin films irradiated with optimized Ar ion beam are promising for practical high-performance hydrogen gas sensors.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.138.1-138.1
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• 2013

We present the low temperature (${\leq}1,000^{\circ}C$) vacuum sublimation behavior of an e-beam evaporative deposited on a SiC film and a method to reduce the vacuum sublimation through an ion beam process. The density of the SiC film deposited using the e-beam evaporation method was ~60% of the density of the bulk source material. We found that the sublimation became appreciable above ${\sim}750^{\circ}C$ under $1.5{\times}10^{-5}$ torr pressure and the sublimation rate increased with an increase in temperature, reaching ~70 nm/h at $950^{\circ}C$ when the coated sample was heated for 5 h. When the film was irradiated with 70 keV N+ ions prior to heating, the sublimation rate decreased to ~23 nm/h at a fluence of $1{\times}10^{17}\;ions/cm^2$. However, a further increase in fluence beyond this value or an extended heating period did not change (decrease or increase) the sublimation rate any further.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.782-785
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• 1997

In this study, the spectra was surface-treated using $Ar^+$ ion beam to improve the tensile property of spectra/vinylester composites. The effect of surface treatment on the tensile property of spectra/vinylester composites was investigated comparing tensile strength and stiffness of surface-treated spectra/vinylester composites with those of untreated spectra/vinylester composites. The results showed that the tensile strength and stiffness of surface-treated s spectra/vinylester composites were 12% and 22% higher than those of untreated spectra/vinylester composites.

• 한국표면공학회지
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• 제35권4호
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• pp.206-210
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• 2002

The use of Spectra fibers as fiber cloth is increasing because of their excellent impact resistance. However, a major limitation on the use of Spectra fibers is a chemical inertness. In this Study, Spectra fibers were surface-treated using Ar$^{+}$ ion beam under oxygen environment to improve the tensile property of Spectra/vinylester composites. The effect of surface treatment of Spectra fibers on the tensile property of Spectra/vinylester composites was determined from tensile tests using Spectra/vinylester composite specimens with and without a hole. It was found that the tensile stiffness and strength of surface-treated case were 22% and 17% higher than those of untreated case for specimens with no hole. The maximum load of surface-treated case was about 15% higher than that of untreated case for specimens with a hole.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.361-364
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• 2000

Antimony doped tin oxide (ATO) thin films were deposited at room temperature by reactive ion-beam sputter deposition (IBSD) technique in oxidizing atmosphere utilizing Sb and Sn metal targets. Effect of Sb doping concentration, film thickness and heat treatment on electrical and optical properties was investigated. The thickness of as-deposited films was controlled approximately to 1500 $\AA$ or 2000$\AA$, and Sb concentration to 10.8 and 14.9 wt%, as determined by SEM and XPS analyses. Heat treatment was performed at the temperature from 40$0^{\circ}C$ to 80$0^{\circ}C$ in flowing $O_2$or forming gas. The resulting ATO films showed widely changing electrical resistivity and optical transmittance values in the visible spectrum depending on the composition, thickness and firing condition.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.188.1-188.1
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• 2014

Aluminum is widely used as a material for electrode on silicon based devices. Especially, aluminum films are used as backside and front-side electrodes in silicon quantum dot (QD) solar cells. In this point, the diffusion of aluminum is very important for the enhancement of power conversion efficiency by improvement of contact property. Aluminum was deposited on a Si (100) wafer and a Si QD layer by ion beam sputter system with a DC ion gun. The Si QD layer was fabricated by $1100^{\circ}C$ annealing of the $SiO_2/SiO_1$ multilayer film grown by ion beam sputtering deposition. Cs ion beam with a low energy and a grazing incidence angle was used in SIMS depth profiling analysis to obtain high depth resolution. Diffusion behavior of aluminum in the Al/Si and Al/Si QD interfaces was investigated by secondary ion mass spectrometry (SIMS) as a function of heat treatment temperature. It was found that aluminum is diffused into Si substrate at $450^{\circ}C$. In this presentation, the effect of heat treatment temperature and Si nitride diffusion barrier on the diffusion of Al will be discussed.

• Journal of Radiation Protection and Research
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• 제46권2호
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• pp.39-47
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• 2021

Background: The National Institutes for Quantum and Radiological Science and Technology-National Institute of Radiological Sciences (QST-NIRS) has continuously investigated the undesired radiation exposure in ion beam radiotherapy mainly in carbon-ion radiotherapy (CIRT). This review introduces our investigations on the secondary neutron dose in CIRT with the broad and scanning beam methods. Materials and Methods: The neutron ambient dose equivalents in CIRT are evaluated based on rem meter (WENDI-II) measurements. The out-of-field organ doses assuming prostate cancer and pediatric brain tumor treatments are also evaluated through the Monte Carlo simulation. This evaluation of the out-of-field dose includes contributions from secondary neutrons and secondary charged particles. Results and Discussion: The measurements of the neutron ambient dose equivalents at a 90#x00B0; angle to the beam axis in CIRT with the broad beam method show that the neutron dose per treatment dose in CIRT is lower than that in proton radiotherapy (PRT). For the scanning beam with the energy scanning technique, the neutron dose per treatment dose in CIRT is lower than that in PRT. Moreover, the out-of-field organ doses in CIRT decreased with distance to the target and are less than the lower bound in intensity-modulated radiotherapy (IMRT) shown in AAPM TG-158 (American Association of Physicists in Medicine Task Group). Conclusion: The evaluation of the out-of-field doses is important from the viewpoint of secondary cancer risk after radiotherapy. Secondary neutrons are the major source in CIRT, especially in the distant area from the target volume. However, the dose level in CIRT is similar or lower than that in PRT and IMRT, even if the contributions from all radiation species are included in the evaluation.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.193-193
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• 2011

Strong adhesion of a silicon carbide (SiC) coating to a WC-Co substrate was achieved through an ion beam mixing technique and the corrosion resistance of the SiC coated WC-Co was investigated by means of a potentiodynamic electrochemical test. In a 1 M NaOH solution, the corrosion current density of SiC-coated WC-Co after heat treatment at 500$^{\circ}C$ was about 50 times lower than that for the as-received WC-Co. In addition, the corrosion resistance systematically increases with increasing the SiC coating thickness. On the other hand, for a 0.5 M H2SO4 solution, the corrosion current density for SiC-coated WC-Co was about 3 times lower than that for the as-received WC-Co. We discuss the physical reasons for the changes in the corrosion current density with the different electrolytes.