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분말 스퍼터링과 후열처리 복합 공정으로 제조한 주석 함유 갈륨 산화물 다공성 나노와이어
이하람,강현철,Lee, Haram,Kang, Hyon Chol 한국결정성장학회 2019 韓國結晶成長學會誌 Vol.29 No.6
라디오주파수 분말 스퍼터링 방법으로 sapphire (0001) 기판 위에 Sn을 함유한 β-Ga<sub>2</sub>O<sub>3</sub>(β-Ga<sub>2</sub>O<sub>3</sub> : Sn) 나노와이어를 증착하였다. 후열처리 공정의 가스 분위기가 나노와이어 형상의 변화에 미치는 영향을 연구하였다. 800℃에서 진공 중 열처리 과정에서, as-grown 나노와이어는 다공성 구조로 전이하였다. 비화학양론 Ga<sub>2</sub>O<sub>3-x</sub>는 화학양론 Ga<sub>2</sub>O<sub>3</sub>로 바뀌고, Sn원자는 응집하여 나노클러스터를 형성한다. Sn 나노클러스터는 증발하여 Sn 원자의 함량은 1.31에서 0.27 at%로 감소하였다. Sn원자의 증발로 인하여 나노와이어 표면에 다수의 기공이 형성되고, 이는 β-Ga<sub>2</sub>O<sub>3</sub> : Sn 나노와이어의 체적대비 표면적 비율을 증가시킨다. We investigated the post-annealing effect of Sn-incorporated β-Ga<sub>2</sub>O<sub>3</sub> (β-Ga<sub>2</sub>O<sub>3</sub> : Sn) nanowires (NWs) grown on sapphire (0001) substrates using radio-frequency powder sputtering. The β-Ga<sub>2</sub>O<sub>3</sub> : Sn NWs were converted to a porous structure during the vacuum annealing process at 800℃. Host non-stoichiometric Ga<sub>2</sub>O<sub>3-x</sub>, is transformed into stoichiometric Ga<sub>2</sub>O<sub>3</sub>, where Sn atoms separate and form Sn nano-clusters that gradually evaporate in a vacuum atmosphere. As a result, the amount of Sn atoms was reduced from 1.31 to 0.27 at%. Pores formed on the sides of β-Ga<sub>2</sub>O<sub>3</sub> : Sn NWs were observed. This increases the ratio of the surface to the volume of β-Ga<sub>2</sub>O<sub>3</sub> : Sn NWs.
서진(Jin Seo),강현철(Hyon Chul Kang),김규형(Kyu Hyung Kim),강한철(Han Chol Kang) 대한소화기학회 1988 대한소화기학회지 Vol.20 No.1
Duodenal cancer is a kind of rare disease and it's incidence is about 0.035% out of 500,000 autopsies (Kleinerman). Malignant lymphoma primarily originated in duodenum is reported more rarely and Allen Good reported only one case of 341 cases of small bowel rnalignancies. Recently, the authors diagnosed one case of primary duodenal lymphoma confirmed by gastrofi- broscopic biopsy, performed pancreaticoduodenectomy radically and postoperative course is relative- ly good. Chemotherapy (C.H.O.P) is given to him. So, we reported here with review of literatures.
다이캐스팅 공정으로 제조한 ADC12 알루미늄 합금의 물성 향상 및 진공 열처리 효과
조지훈,함다슬,오성찬,차수연,강현철,Jo, Jihoon,Ham, Daseul,Oh, Seongchan,Cha, Su Yeon,Kang, Hyon Chol 한국결정성장학회 2021 한국결정성장학회지 Vol.31 No.1
We report structural, mechanical, and thermal properties of diecast ADC12 aluminum alloys characterized using synchrotron X-ray diffraction (XRD), scanning electron microscopy, energy dispersive X-ray (EDX) analysis, thermal conductivity (λ), Vickers hardness (Hv), and stress-strain measurements. We also studied the effect of post-annealing performed in a vacuum atmosphere on the mechanical properties of diecast ADC12 alloys. EDX and XRD results revealed that Al2Cu and AlCu3 grains are formed, well dispersed in Al base and highly crystalline. Ultimate tensile strength (UTS) of 307.9 ± 9.1 MPa and elongation of 2.98 ± 0.62 % were estimated. λ was 129.3 ± 0.27 W/m·K and Hv was approximately 130. Both values were significantly higher than the reported values. At annealing temperatures ranging from 25 to 200℃, UTS and Hv values remained constant, while as the annealing temperature increased to 500℃, these values gradually decreased. This is because stabilization of the microstructure improves toughness and ductility. 최적의 조건에서ADC12 알루미늄 합금을 다이캐스팅 기법으로 제조하여 구조적, 기계적, 열적 성질을 연구하였다. 또한 진공에서 후속 열처리한 ADC12 알루미늄 합금의 기계적 물성 변화를 규명하였다. 방사광 X-선 회절 및 energy dispersive X-선 화학조성 분석법을 통하여 ADC12 합금은 알루미늄 기저에 알루미늄과 구리의 화합물인 Al2Cu 및 AlCu3 상이 결정질 형태로 분포하고 있음을 규명하였다. 대표적인 기계적 물성값인 인장강도와 연신율은 각각 307.9 ± 9.1 MPa와 2.98 ± 0.62 %이다. 기존 보고보다 우수한 열전도도(129.3 ± 0.27 W/m·K)와 비이커스 경도값(Hv = 130)을 나타낸다. 후속 열처리 결과, 200℃까지는 기계적 물성치가 일정하게 유지되었으나, 이후 500℃까지 열처리 온도를 증가시킬 경우에는 인장강도와 비이커스 경도가 점진적으로 감소하였다. 이는 열처리 도중 미세조직이 안정화되면서 인성과 연성이 향상되었기 때문이다.
수열합성법을 이용한 산화아연 나노와이어의 에피택시 성장
함다슬,정병언,양명훈,이종관,최영빈,강현철,Ham, Daseul,Jeong, Byeong Eon,Yang, Myeong Hun,Lee, Jong Kwan,Choi, Young Bin,Kang, Hyon Chol 한국전기전자재료학회 2018 전기전자재료학회논문지 Vol.31 No.7
Epitaxial ZnO nanowires (NWs) were synthesized on sapphire (001) substrates using a hydrothermal process. The effects of the pH value of the precursor solution on the structural and optical properties of the resulting NWs was studied. The epitaxial relationship and the domain matching configuration between the sapphire (001) substrate and the as-grown ZnO NWs were determined using synchrotron X-ray diffraction measurements. The (002) plane of $w{\ddot{u}}rtzite$ ZnO NW grows in the surface normal direction parallel to the sapphire (001) direction. However, three types of in-plane domain matching configurations were observed, such as the on-position, $30^{\circ}$-rotated position, and ${\pm}8.5^{\circ}$-rotated position relative to the on-position, which might be attributed to inheriting the in-plane domain configuration of the ZnO seed layer.
라디오주파수 분말 스퍼터링 방법으로 성장시킨 주석을 도핑한 산화아연 박막의 열처리
이하람 ( Haram Lee ),정병언 ( Byeong Eon Jeong ),양명훈 ( Myeong Hun Yang ),이종관 ( Jong Kwan Lee ),최영빈 ( Young Bin Choi ),강현철 ( Hyon Chol Kang ) 한국열처리공학회 2018 熱處理工學會誌 Vol.31 No.3
We report the post-annealing effect of Sn doped ZnO (ZnO:Sn) thin film grown on sapphire (001) sub-strate using radio-frequency powder sputtering method. During thermal annealing in a vacuum atmosphere, the ZnO:Sn thin film is transformed into a porous thin film. Based on X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray analyses, a possible mechanism for the production of pores is presented. Sn atoms segregate to form clusters that act as catalysts to dissociate Zn-O bonds. The Zn and O atoms subsequently vaporize, leading to the formation of pores in the ZnO:Sn thin film. We also found that Sn clusters were oxidized to form SnO or SnO<sub>2</sub> phases. (Received April 20, 2018; Revised April 27, 2018; Accepted May 4, 2018)