• Journal of the Korean Geotechnical Society
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• v.16 no.6
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• pp.51-58
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• 2000

울산지역에 널리 분포하고 있는 해성 퇴적토에 대하여 깊이별로 물리, 화학 그리고 광물학적 특성을 파악하였으며, 이 지역에서 채취된 시료에 대하여 깊이별로 퓨준압말시험을 실시하였다. 본 논문을 위하여 울산 해성 퇴적토의 생성과정을 추정하고, X-선 회절 분석, X-선 형광분석 및 에너지분산분광분석을 실시하여 깊이에 따른 변화를 비교하였다. 울산 해성 퇴적토의 점토광물에 대한 정량분석결과, 일라이트, 카올리나이트, 녹니석, 스멕타이트 순으로 많게 나타났음, 화학성분 분석결과, SiO$_2$, $Al_2$O$_3$그리고 Fe$_2$O$_3$가 대부분을 차지하는 것으로 나타났다. 주사전자현미경 관찰결과, 유공충과 규조류가 관찰되었다. 표준압밀시험 결과, 울산지역의 해성 퇴적 점토는 깊이에 따른 변형거동이 화학적, 광물학적 분석결과와 마찬가지로 깊이에 따른 변화를 보이지 않아 같은 시디에 퇴적인 것으로 판단된다.

• Journal of the Korean Ceramic Society
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• v.51 no.4
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• pp.312-316
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• 2014

The joining behavior of forsterite ceramics to SUS304 alloy using $8PbO-78Bi_2O_3-8B_2O_3-4ZnO-2SiO_2$ (wt%) system glass frit was investigated. The contact angle was smaller than $90^{\circ}$ at a temperature of $460^{\circ}C$. Redox reaction at the interface between forsterite and SUS304 was found to appear when the electrons in the metal part moved toward the glass part and the oxygen ions in glass moved to the metal side. The decrease of the surface tension due to the PbO solubility on the forsterite side contributed to the better wetting behavior at low temperature.

• Transactions on Electrical and Electronic Materials
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• v.16 no.4
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• pp.187-189
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• 2015

A charge-trap flash (CTF) thin film transistor (TFT) memory is proposed at a low-temperature process (≤ 450℃). The memory cell consists of a sputtered oxide-nitride-oxide (ONO) gate dielectric and Schottky barrier (SB) source/drain (S/D) junctions using nickel silicide. These components enable the ultra-low-temperature process to be successfully achieved with the ONO gate stacks that have a substrate temperature of room temperature and S/D junctions that have an annealing temperature of 200℃. The silicidation process was optimized by measuring the electrical characteristics of the Ni-silicided Schottky diodes. As a result, the Ion/Ioff current ratio is about 1.4×10⁵ and the subthreshold swing and field effect mobility are 0.42 V/dec and 14 cm²/V·s at a drain voltage of −1 V, respectively.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1065-1066
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• 2006

The aging behavior of sintered Al composites with various ceramic contents was investigated. 2xxx series blended powder was used as the starting powder. Ceramic contents were 0wt.% and 5wt.%. The blended powders were compacted at 250MPa. The sintering process was performed at $620^{\circ}C$ for 60min in a $N_2$ atmosphere. Each part was solution-treated at $518^{\circ}C$ for 60min and aged at $180^{\circ}C$. The Rockwell hardness at the peak aging time increased with ceramic contents. However, the peak aging time at maximum hardness was reduced with increased ceramic contents.

• Korean Journal of Plant Resources
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• v.21 no.6
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• pp.427-430
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• 2008

Here we reported two unrecorded naturalized species from Korean flora. Andropogon virginicus L. of Graminaeae and Euphorbia postrata Aiton of Euphorbiaceae are collected from Dong-gu, Ulsan-si and Sinjindo-ri, Taean-gun, Chungcheongnam-do respectively. A. virginicus L. was easily distinguishable from Themeda triandras var. japonica Makino by keel on glume, 2-4 racemes and long hairy rachis. Thus, the new Korean name, 'Na-do-sol-sae', was given. E. postrata Aiton was cleary distinguished from related taxa by hairs on only edges of fruits. The new Korean name, 'Nu-un-ttang-bin-dae' was given considering the species epithet. Descriptions, illustrations and photographs showing habitat were given.

• Journal of the Korean Vacuum Society
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• v.4 no.S1
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• pp.13-20
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• 1995

As으로 in-situ 도핑된 폴리실리콘 막을 원하는 부위에만 선택적으로 증착시킬 수 있는 RTP-CVD 증착기술이 성공적으로 수행되었다. 막의 증착속도는 도핑량이 증차함에 따라 점차 감소하였으나 As의 양이 5ppm보다 커지자 급격히 감소하였다. 또한 증착속도는 As의 유량이 일정할 때, SiH2CI2 유량에 따라 직선적으로 변화하였다. As 도펀트의 농도는 막내부에 비해 폴리실리콘/실리콘기판의 계면과 표면에서 상대적으로 높게 나타났으며, 특히 증착온도가 낮을 때 As 도펀트의 농도는 더 높아짐을 알 수 있었다. 실리콘 표면에서 약 40-50nm 위치에서 도펀트의 농도천이가 급격히 일어났으며, 그 결과 RTP-CVD공정을 이용할 때 극히 얕고 일정한 깊이분포를 갖는 n+-p junctions were achieved and laterally uniform delineated junctions were also observed using RTP-CVD.

• International Journal of Korean Welding Society
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• v.2 no.1
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• pp.62-66
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• 2002

The Friction Stir Welding (FSW) is a new joining method that was developed at The Welding Institute (TWI) in England in 1991. It applied heating by the rotational friction and material plastic flow. It was developed as a new joining method to solve the problems of epochally in the welding of Al alloys. In the study, 6000series of Alloy composed of Al-Mg-Si, one of the Al alloys that are utilized for shipbuilding and construction, is selected as a specimen and the numerical is executed against the welded zone of FSW. The material used in this study had the unique properties of strength and anti-corrosion, but since the welded joint of this material is easily softened by the welding heat, FSW is executed and the numerical analysis is carried out around the joint. To examine the mechanical behaviors and properties, F.E.M analysis is executed and the developed thermal-elastic-plastic finite analysis are used.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.2
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• pp.133-140
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• 2024

This study offers a comprehensive evaluation of the role and impact of advanced power semiconductors in solar module systems. Focusing on silicon carbide (SiC) and gallium nitride (GaN) materials, it highlights their superiority over traditional silicon in enhancing system efficiency and reliability. The research underscores the growing industry demand for high-performance semiconductors, driven by global sustainable energy goals. This shift is crucial for overcoming the limitations of conventional solar technology, paving the way for more efficient, economically viable, and environmentally sustainable solar energy solutions. The findings suggest significant potential for these advanced materials in shaping the future of solar power technology.

• Progress in Medical Physics
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• v.26 no.4
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• pp.286-293
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• 2015

The purpose of this study was to evaluate the set up accuracy using stereotactic body frame and frameless immobilizer for lung stereotactic body radiation therapy (SBRT). For total 40 lung cancer patients treated by SBRT, 20 patients using stereotactic body frame and other 20 patients using frameless immobilizer were separately enrolled in each group. The setup errors of each group depending on the immobilization methods were compared and analyzed. All patients received the dose of 48~60 Gy for 4 or 5 fractions. Before each treatment, a patient was first localized to the treatment isocenter using room lasers, and further aligned with a series of image guidance procedures; orthogonal kV radiographs, cone-beam CT, orthogonal fluoroscopy. The couch shifts during these procedures were recorded and analyzed for systematic and random errors of each group. Student t-test was performed to evaluate significant difference depending on the immobilization methods. The setup reproducibility was further analyzed using F-test with the random errors excluding the systematic setup errors. In addition, the ITV-PTV margin for each group was calculated. The setup errors for SBF were $0.05{\pm}0.25cm$ in vertical direction, $0.20{\pm}0.38cm$ in longitudinal direction, and $0.02{\pm}0.30cm$ in lateral direction, respectively. However the setup errors for frameless immobilizer showed a significant increase of $-0.24{\pm}0.25cm$ in vertical direction while similar results of $0.06{\pm}0.34cm$, $-0.02{\pm}0.25cm$ in longitudinal and lateral directions. ITV-PTV margins for SBF were 0.67 cm (vertical), 0.99 cm (longitudinal), and 0.83 cm (lateral), respectively. On the other hand, ITV-PTV margins for Frameless immobilizer were 0.75 cm (vertical), 0.96 cm (longitudinal), and 0.72 cm (lateral), indicating less than 1 mm difference for all directions. In conclusion, stereotactic body frame improves reproducibility of patient setup, resulted in 0.1~0.2 cm in both vertical and longitudinal directions. However the improvements are not substantial in clinic considering the effort and time consumption required for SBF setup.

• Radiation Oncology Journal
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• v.26 no.4
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• pp.195-203
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• 2008

Purpose: To investigate the treatment outcome and failure patterns after definitive chemoradiation therapy in locally advanced, unresectable esophageal cancer. Materials and Methods: From February 1994 to December 2002, 168 patients with locally advanced unresectable or medically inoperable esophageal cancer were treated by definitive chemoradiation therapy. External beam radiation therapy (EBRT) ($42{\sim}46\;Gy$) was delivered to the region encompassing the primary tumor and involved lymph nodes, while the supraclavicular fossa and celiac area were included in the treatment area as a function of disease location. The administered cone-down radiation dose to the gross tumor went up to $54{\sim}66\;Gy$, while the fraction size of the EBRT was 1.8-2.0 Gy/fraction qd or 1.2 Gy/fraction bid. An optional high dose rate (HDR) intraluminal brachytherapy (BT) boost was also administered (Ir-192, $9{\sim}12\;Gy/3{\sim}4\;fx$). Two cycles of concurrent FP chemotherapy (5-FU $1,000\;mg/m^2$/day, days $2{\sim}6$, $30{\sim}34$, cisplatin $60\;mg/m^2$/day, days 1, 29) were delivered during radiotherapy with the addition of two more cycles. Results: One hundred sixty patients were analyzable for this review [median follow-up time: 10 months (range $1{\sim}149$ months)). The number of patients within AJCC stages I, II, III, and IV was 5 (3.1%), 38 (23.8%), 68 (42.5%), and 49 (30.6%), respectively. A HDR intraluminal BT was performed in 26 patients. The 160 patients had a median EBRT radiation dose of 59.4 Gy (range $44.4{\sim}66$) and a total radiation dose, including BT, of 60 Gy (range $44.4{\sim}72$), while 144 patients received a dose higher than 40 Gy. Despite the treatment, the disease recurrence rate was 101/160 (63.1%). Of these, the patterns of recurrence were local in 20 patients (12.5%), persistent disease and local progression in 61 (38.1%), distant metastasis in 15 (9.4%), and concomitant local and distant failure in 5 (3.1%). The overall survival rate was 31.8% at 2 years and 14.2% at 5 years (median 11.1 months). Disease-free survival was 29.0% at 2 years and 22.7% at 5 years (median 10.4 months). The response to treatment and N-stage were significant factors affecting overall survival. In addition, total radiation dose (${\geq}50\;Gy$ vs. < 50 Gy), BT and fractionation scheme (qd. vs. bid.) were not significant factors for overall survival and disease-free survival. Conclusion: Survival outcome after definitive chemoradiation therapy in unresectable esophageal cancer was comparable to those of other series. The main failure pattern was local recurrence. Survival rate did not improve with increased radiation dose over 50 Gy or the use of brachytherapy or hyperfractionation.