• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.276-276
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• 2013

Time-Of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) and Atomic Force Microscopy (AFM) are the useful instruments to measure nanostructures of material surfaces. Surface pattern formation in blending homopolymer and diblock copolymer films was investigated as a function of film thickness and annealing conditions. In this study, surface structures of blending homopolymer [deuterated polystyrene (Mn 20,000), poly (methyl methacrylate) (Mn 18,000)] and diblock copolymer [Poly (deuteratedstyrene(d8)-b-methyl methacrylate) (Mn 19,500-18,100)] films were observed. The AFM result indicated that the nanostructures and film thickness depended on temperature, concentration and solvent. TOF-SIMS depth profiling was obtained for the lamellar morphology of symmetric dPS-b-PMMA which is found to orient parallel to the surface of the substrate. Elemental and molecular depth profiles measured in the negative ion mode by a Cs+ primary ion beam demonstrate variations in hydrogen, deuterium, carbon, oxygen, hydrocarbons and deuterated hydrocarbons within the diblock copolymer according to the depth.

• Fire Science and Engineering
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• v.22 no.5
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• pp.43-47
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• 2008

Recently SIMS has attracted interest as new technique to distinguish the primary and the secondary arc beads. A Cs+ primary ion beam was used to detect the $^{12}C^-$, $^{63}Cu^-$, $^{18}O^-$, $^{35}Cl^-$ secondary ions which are formed during depth profiles in the copper wires. In this work, we studied thermal diffusion in the copper wire which are occurred with supplying over-current. The results demonstrated that Carbon and Chloride are diffused in PVC-coated copper wire deeper than none PVC-coated. However Oxygen showed the reverse diffusion property.

• Journal of Periodontal and Implant Science
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• v.43 no.1
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• pp.18-23
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• 2013

Purpose: The purpose of this study was to evaluate the osseointegration of calcium phosphate (CaP)-coated implants by ion beam assisted deposition with a lack of primary stability. Methods: A total of 20 CaP-coated implants were bilaterally placed in the mandible of five dogs. In the rotational implant group, the implants were inserted in oversized drilled sockets without mechanical engagement, while the conventional surgical protocol was followed in the control group. Each group was allowed to heal for 4 and 8 weeks. The bone-to-implant contact (BIC, %) was measured by a histometric analysis. Results: All of the implants were well-maintained and healing was uneventful. In the histologic observation, all of the implants tested were successfully osseointegrated with a high level of BIC at both observation intervals. There was no significant difference in BIC among any of the groups. Conclusions: Within the limitation of this study, successful osseointegration of CaP-coated implants could be achieved in unfavorable conditions without primary stability.

• Analytical Science and Technology
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• v.19 no.5
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• pp.400-406
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• 2006

Hydrogen analysis by elastic recoil detection has been performed utilizing polyimide film as a reference sample of known hydrogen content assuming the soundness of ion beam current integration. However beam current integration at higher incidence angle is not reliable. Scattering yield per unit fluence by current integration which is normalized per unit path length decreases as the sample tilt angle is getting higher. Moreover because beam current integration at high tilt angle is incomplete, hydrogen evaluation is very risky by direct comparison of sequentially collected recoil spectra between reference and target sample. In this study, primary ion beam dose is determined by backscattering spectrum that is collected simultaneously with recoil spectrum instead of ion beam current integration in order to reduce uncertainty arising in the process of current integration and to enhance the reliability of quantitative analysis. Three test samples are selected $-7.6{\mu}m$ polyimide film, hydrogen implanted silicondioxide and Au deposited carbon wafer- and analyzed by two methods and compared.

• Nuclear Engineering and Technology
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• v.52 no.10
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• pp.2410-2414
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• 2020

Heavy ions have a high potential for destroying deep tumors that carry the highest dose at the peak of Bragg. The peak caused by a single-energy carbon beam is too narrow, which requires special measures for improvement. Here, carbon-12 (¹²C) ion with different energies has been used as a source for calculating the dose distribution in the water phantom, soft tissue and bone by the code of Monte Carlobased FLUKA code. By increasing the energy of the initial beam, the amount of absorbed dose at Bragg peak in all three targets decreased, but the trend for this reduction was less severe in bone. While the maximum absorbed dose per bone-mass unit in energy of 200 MeV/u was about 30% less than the maximum absorbed dose per unit mass of water or soft tissue, it was merely 2.4% less than soft tissue in 400 MeV/u. The simulation result showed a good agreement with experimental data at GSI Darmstadt facility of biophysics group by 0.15 cm average accuracy in Bragg peak positioning. From 200 to 400 MeV/u incident energy, the Bragg peak location increased about 18 cm in soft tissue. Correspondingly, the bone and soft tissue revealed a reduction dose ratio by 2.9 and 1.9. Induced neutrons did not contribute more than 1.8% to the total energy deposited in the water phantom. Also during ¹²C ion bombardment, secondary fragments showed 76% and 24% of primary 200 and 400 MeV/u, respectively, were present at the Bragg-peak position. The combined treatment of carbon ions with neutron or electron beams may be more effective in local dose delivery and also treating malignant tumors.

• Nuclear Engineering and Technology
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• v.53 no.8
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• pp.2767-2773
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• 2021

We used the GEANT4 Monte Carlo MC Toolkit to simulate carbon ion beams incident on water, tissue, and bone, taking into account nuclear fragmentation reactions. Upon increasing the energy of the primary beam, the position of the Bragg-Peak transfers to a location deeper inside the phantom. For different materials, the peak is located at a shallower depth along the beam direction and becomes sharper with increasing electron density NZ. Subsequently, the generated depth dose of the Bragg curve is then benchmarked with experimental data from GSI in Germany. The results exhibit a reasonable correlation with GSI experimental data with an accuracy of between 0.02 and 0.08 cm, thus establishing the basis to adopt MC in heavy-ion treatment planning. The Kolmogorov-Smirnov K-S test further ascertained from a statistical point of view that the simulation data matched the experimentally measured data very well. The two-dimensional isodose contours at the entrance were compared to those around the peak position and in the tail region beyond the peak, showing that bone produces more dose, in comparison to both water and tissue, due to secondary doses. In the water, the results show that the maximum energy deposited per fragment is mainly attributed to secondary carbon ions, followed by secondary boron and beryllium. Furthermore, the number of protons produced is the highest, thus making the maximum contribution to the total dose deposition in the tail region. Finally, the associated spectra of neutrons and photons were analyzed. The mean neutron energy value was found to be 16.29 MeV, and 1.03 MeV for the secondary gamma. However, the neutron dose was found to be negligible as compared to the total dose due to their longer range.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.1
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• pp.131-143
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• 2007

Statement of the problem: In case of poor bone quality or immediately loaded implant, various strategies have been developed focusing on the surface of materials to improve direct implant fixation to the bone. The microscopic properties of implant surfaces play a major role in the osseous healing of dental implant. Purpose of study: This study was undertaken to evaluate bone response of ion beam-assisted deposition(IBAD) of hydroxyapatite(HA) on the anodized surface of subperiosteal titanium implants. Material and methods: Two half doughnut shape subperiosteal titanium implants were made. The control group was treated with Anodized surface treatment and the test group was treated with IBAD of HA on control surface. Then two implants inserted together into the subperiosteum of the skull of 30 rats and histological response around implant was observed under LM(light microscope) and TEM(transmission electron microscope) on 4th, 6th and 8th week. Results: Many subperiosteal implants were fixed with fibrous connective tissue not with bony tissue because of weak primary stability. The control group observed poor bone response and there was no significant change at any observation time. However the test group showed advanced bone formation and showed direct bone to implant contact under LM on 8th week. The test group observed much rER in the cell of osteoblast but the control group showed little rER under TEM. Conclusions: The test group showed better bone formation than the control group at the condition of weak primary stability. With these results IBAD surface treatment method on Anodized surface, may be good effect at the condition of weak primary stability.

• Journal of the Korean Vacuum Society
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• v.14 no.2
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• pp.91-96
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• 2005

The silicon-on-insulator (SOI) wafer fabrication technique has been developed by using ion-cut process, based on proton implantation and wafer bonding techniques. It has been shown by SRIM simulation that 65keV proton implantation is required for a SOI wafer (200nm SOI, 400nm BOX) fabrication. In order to investigate the optimum proton dose and primary annealing condition for wafer splitting, the surface morphologic change has been observed such as blistering and flaking. As a result, effective dose is found to be in the $6\~9\times10^{16}\;H^+/cm^2$ range, and the annealing at $550^{\circ}C$ for 30 minutes is expected to be optimum for wafer splitting. Direct wafer bonding is performed by joining two wafers together after creating hydrophilic surfaces by a modified RCA cleaning, and IR inspection is followed to ensure a void free bonding. The wafer splitting was accomplished by annealing at the predetermined optimum condition, and high temperature annealing was then performed at $1,100^{\circ}C$ for 60 minutes to stabilize the bonding interface. TEM observation revealed no detectable defect at the SOI structure, and the interface trap charge density at the upper interface of the BOX was measured to be low enough to keep 'thermal' quality.

• Corrosion Science and Technology
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• v.14 no.6
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• pp.301-312
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• 2015

Corrosion of zirconium fuel cladding is known to limit the lifetime and reloading cycles of fuel in nuclear reactors. Oxide layers formed on ZIRLO4^{TM}$ cladding samples, after immersion for 300-hour and 50-day in a simulated primary water chemistry condition ($360^{\circ}C$ and 20 MPa), were analyzed by using the scanning transmission electron microscopy (STEM), in-situ transmission electron microscopy (in-situ TEM) with the focused ion beam (FIB) technique, and X-ray diffraction (XRD). Both samples (immersion for 300 hours and 50 days) revealed the presence of the ZrO sub-oxide phase at the metal/oxide interface and columnar grains developed perpendicularly to the metal/oxide interface. Voids and micro-cracks were also detected near the water/oxide interface, while relatively large lateral cracks were found just above the less advanced metal/oxide interface. Equiaxed grains were mainly observed near the water/oxide interface.

• Analytical Science and Technology
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• v.14 no.6
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• pp.486-493
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• 2001

The effect of SIMS analysis conditions such as mesh grid, offset voltage and ion species on the in-depth profile for bismuth titanate thin film was examined in terms of charging effect and detection limit. The results shows that the use of offset voltage -40 V reduces the charging effect and the detection limit. The employment of mesh grid in sample preparation leads to the reduction of the charging effect in small amount, but deteriorate the detection limit. Utilization of primary $O^-$ ion for SIMS analysis of bismuth titanate thin film showed almost the same effect as using offset voltage -40 V. However, it takes approximately triple acquisition time than using $O_2{^+}$ ion due to the poor beam current of the source in the experiment.