• 한국자기학회:학술대회 개요집
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• 한국자기학회 2007년도 The 1st International Symposium on Advanced Magnetic Materials
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• pp.297.1-297.1
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• 2007

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.300-300
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• 2008

In this study, the advanced DuoPIGatron-type ion beam (IB) system was applied to inorganic thin film for aligning liquid crystal (LC). LC alignment on $Ta_2O_5$ via IB irradiation was embodied. As a result of IB irradiation, the homogeneously aligned liquid crystal display (LCD) on $Ta_2O_5$ was observed with low pretilt angles. The $Ta_2O_5$ were deposited on indium-tin-oxide coated Coming 1737 glass substrates by rf magnetron sputtering at $200^{\circ}C$. The deposition process resulted in forming very uniform thin film on glass substrates without any defects. To confirm the application of the inorganic alignment on modem display optical devices, we fabricated twisted nematic LCD and measured optical property and response time. As a result of the experiment, the electro optical characteristics of the LCD fabricated by using IB irradiation on $Ta_2O_5$ alignment layer were similar with the other LCD fabricated by using rubbing process.

• 공업화학
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• 제9권1호
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• pp.28-32
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• 1998

두 종류의 유기인계 살충제인 디클로로보스와 클로로피리포스를 UV조사, UV 조사와 $TiO_2$분말 그리고 UV조사와 sea sand를 저압수은 램프를 이용하여 분해실험을 하였다. 이 화합물의 확인은 가스크로마토그래프, 총유기탄소 그리고 이온크로마토그래프를 사용하였다. 두 물질 모두, UV조사와 sea sand가 UV 조사와 UV조사와 $TiO_2$분말보다 분해가 더 잘 되었다. 반응 최종생성물은 디클로르보스에서는 $Cl^-$, 클로로피리포스에서는 $Cl^-$ $SO_4{^{2-}}$등이 생성되었다.

• 한국진공학회지
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• 제10권1호
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• pp.37-43
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• 2001

반응성 산소 분위기에서 불소계 고분자에 1 keV 아르곤 이온을 조사하였다. 이온 조사에 의하여 발생한 free radical과 산소 기체와의 화학 반응에 의하여 표면에 -(C-O)-,-(C=O)-,-(C=O)-O-등의 친수성 작용기가 생성되었으며 PVDF에 대한 물의 접촉각은 $75^{\circ}$에서 $31^{\circ}$로 감소하였다. 그러나 이온조사량이 큰 경우 고분자 표면에 탄화 상이 형성됨으로써 접촉각은 다시 $65^{\circ}$로 증가하였다. PTFE에 대한 접촉각은 초기에 감소하였다가 표면 거칠기가 급격히 증가함에 따라 접촉각은 더욱 크게 나타났다. 이온 조사에 의하여 표면에 형성된 극성 작용기에 의해 PVDF와 Pt의 접착력은 급격히 증가하였으며 이는 산-염기 상호작용 때문이다. PTFE와 Cu의 경우, 극성 작용기와 금속간의 화학적 결합에 의하여 접착력이 크게 증가하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.202-202
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• 1999

The Polyethylene (PE), Polystyrene (PS) and Polytetrafluoroethylene (PTFE) surface modification was investigated by hydrogen io assisted reaction (H-IAR) in oxygen environment. The IAR is a kind of surface modification techniques using ion beam irradiation in reactive gas environment. The energy of hydrogen ion beam was fixed at 1keV, io dose was varied from 5$\times$1014 to 1$\times$1017 ions/$\textrm{cm}^2$, and amount of oxygen blowing gas was fixed 4ml/min. Wettability was measured by water contact angles measurement, and the surface functionality was analyzed by x-ray photoelectron spectroscopy. The contact angle of water on PE modified by argon ion beam only decrease from 95$^{\circ}$ to 52$^{\circ}$, and surface energy was not changed significantly. But, the contact angle using hydrogen ion beam with flowing 4ml/min oxygen stiffly decreased to 8$^{\circ}$ and surface energy to 65 ergs/cm. In case of PS, the contact angle and surface energy changes were similar results of PE, but the contact angle of PTEE samples decreased with ion dose up to 1$\times$1015 ions/$\textrm{cm}^2$, increased at higher dose, and finally increased to the extent that no wetting was appeared at 1$\times$1017 ions/$\textrm{cm}^2$. These results must be due to the hydrogen ion beam that cleans the surface removing the impurities on polymer surfaces, then hydrogen ion beam was activated with C-H bonding to make some functional groups in order to react with the oxygen gases. Finally, unstable polymer surface can be changed from hydrophobic to hydrophilic formation such as C-O and C=O that were confirmed by the XPS analysis, conclusionally, the ion assisted reaction is very effective tools to attach reactive ion species to form functional groups on C-C bond chains of PE, PS and PTFE.

• Bulletin of the Korean Chemical Society
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• 제23권2호
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• pp.309-314
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• 2002

The ablation dynamics and cluster formation of $C_n^+$ ions ejected from 355 nm laser ablation of a graphite target in vacuum are investigated using a reflectron time-of-flight (RTOF) mass spectrometer. At low laser fluence, odd-numbered cluster ions with $3{\leq}n{\leq}15$ are predominantly produced. Increasing the laser fluence shifts the maximum size distribution towards small cluster ions, implying the fragmentation of larger clusters within the hot plume. The temporal evolution of $C_n^+$ ions was measured by varying the delay time of the ion extraction pulse with respect to the laser irradiation, providing significant information on the characteristics of the ablated plume. Above a laser fluence of $0.2J/cm^2$ , large cluster ions ($n{\geq}30$) are produced at relatively long delay times, indicating that atoms or small carbon clusters aggregate during plume propagation. The dependence of the intensity of ablated $C_n^+$ ions on delay time after laser irradiation shows that the most probable velocity of each cluster ion decreases with cluster size.

• Nuclear Engineering and Technology
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• 제50권1호
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• pp.132-139
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• 2018

Nanocrystalline reduced activation ferritic/martensitic (RAFM) steel samples were prepared using surface mechanical attrition treatment (SMAT). Un-SMATed and SMATed reduced activation ferritic/martensitic samples were irradiated by helium ions at $200^{\circ}C$ and $350^{\circ}C$ with 2 dpa and 8 dpa, respectively, to investigate the effects of grain boundaries (GBs) and temperature on the formation of He bubbles during irradiation. Experimental results show that He bubbles are preferentially trapped at GBs in all the irradiated samples. Bubble denuded zones are clearly observed near the GBs at $350^{\circ}C$, whereas the bubble denuded zones are not obvious in the samples irradiated at $200^{\circ}C$. The average bubble size increases and the bubble density decreases with an increasing irradiation temperature from $200^{\circ}C$ to $350^{\circ}C$. Both the average size and density of the bubbles increase with an increasing irradiation dose from 2 dpa to 8 dpa. Bubbles with smaller size and lower density were observed in the SMATed samples but not in the un-SMATed samples irradiated in the same conditions, which indicate that GBs play an important role during irradiation, and sink strength increases as grain size decreases.

• Transactions on Electrical and Electronic Materials
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• 제7권6호
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• pp.301-304
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• 2006

We studied the nematic liquid crystal (NLC) aligning capabilities using the new alignment material of the SiC (Silicon Carbide) thin film. The SiC thin film exhibits good chemical and thermal stability. The good thermal and chemical stability make SiC an attractive candidate for electronic applications. A vertical alignment of nematic liquid crystal by atomic beam exposure on the SiC thin film surface was achieved. The about $87^{\circ}$ of stable pretilt angle was achieved at the range from $30^{\circ}\;to\;45^{\circ}$ of incident angle. Consequently, the vertical alignment effect of liquid crystal electro-optical characteristic by the atomic beam alignment method on the SiC thin film layer can be achieved.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.627-636
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• 2022

In nuclear power plants and other nuclear facilities the removal of cobalt from radioactive liquid waste is needed to reduce the radioactivity concentration in effluents. In liquid wastes containing strong organic complexing agents such as EDTA cobalt removal can be problematic due to the high stability of the Co-EDTA complex. In this study, the removal of cobalt from NaNO₃ solutions using antimony oxide (Sb₂O₃) synthesized from potassium hexahydroxoantimonate was investigated in the absence and presence of EDTA. The uptake studies on the ion exchange material were conducted both in the dark (absence of UV-light) and under UV-C irradiation. Ca²⁺ or Ni²⁺ were included in the experiments as competing cations to test the selectivity of the ion exchanger. Results show that UV-C irradiation noticeably enhances the cobalt sorption efficiency on the antimony oxide. It was shown that nickel decreased the sorption of cobalt to a higher extent than calcium. Finally, the sorption data collected for Co²⁺ on antimony oxide was modeled using six different isotherm models. The Sips model was found to be the most suitable model to describe the sorption process. The Dubinin-Radushkevich model was further used to calculate the adsorption energy, which was found to be 6.2 kJ mol^-1.

• 한국재료학회지
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• 제10권1호
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• pp.77-82
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• 2000

1 keV $Ar^+$ 이온빔을 이용하여 polytetrafluoroethylene (PTFE)의 표면을 개질하고 그 위에 $5000\;{\AA}$의 구리 박막을 이온빔 스퍼터링법을 이용하여 증착하였다. 이온빔 조사에 의하여 PTFE의 표면에는 cone이 형성되며 cone의 높이는 이온 조사량이 증가함에 따라 점차로 증가함을 알 수 있었다. x-ray photoelectron spectroscopy (XPS) 분석을 통하여 조사된 PTFE의 표면에서는 이온 조사량이 증가함에 따라 Fls peak의 강도가 감소하며 이는 F 원자의 선택적인 스퍼터링에 기인한 것으로 생각된다. 또한 이온 조사에 의해 생성된 불안정한 사슬들은 crosslinking에 의하여 새로운 C-F 계열의 결합들을 생성하였다. 이온빔 스퍼터링법에 의하여 증착된 구리 박막은 PTFE 표면의 cone을 따라 균일하게 증착되며 PTFE의 표면 거칠기가 증가함에 따라 (111) 방향으로 우선 성장함을 알 수 있었다. 증착된 구리 박막의 비저항은 개질전 PTFE의 $2.7{\mu}{\Omega}cm$에서 $1{\tiems}10^{16}/\textrm{cm}^2$의 이온 조사량으로 개질된 PTFE의 $4.3{\mu}{\Omega}cm$까지 이온 조사량에 따라 점차로 증가하였다. $1{\tiems}10^{17}/\textrm{cm}^2$의 이온 조사량으로 개질된 PTFE 위에 증착된 구리 박막의 갑작스런 비저항 증가는 구리 박막의 단락에 의한 것으로 보인다.