양극산화와 열수처리한 니오비움 금속의 표면특성

원대희,김영순,윤동주,이민호,배태성,Won Dae-Hee,Kim Young-Soon,Yoon Dong-Joo,Lee Min-Ho,Bae Tae-Sung 한국재료학회 2005 한국재료학회지 Vol.15 No.2

This study was performed to investigate the surface properties of electrochemically oxidized pure niobium by anodic oxide and hydrothermal treatment technique. Niobium specimens of $10mm\times10mm\times1.0mm$ in dimension were polished sequentially from $\#600,\;\#800,\;\#1000$ emery paper. The surface of pure niobium sperimens was anodized in an electrolytic solution that was dissolved calcium and phosphate in water. The electrolytic voltage was set in the range of 250 V and the current density was $10mA/cm^2$. The specimen was hydrothermal treated in high-pressure steam at $300^{\circ}C$ for 2 hours using an autoclave. And all specimens were immersed in the in the Hanks' solution nth pH 7.4 at $37^{\circ}C$ for 30 days. The surface of specimen was characterized by surface roughness, scanning electron microscope(SEM), energy dispersion X-ray analysis(EDX), X-ray photoemission spectroscopy(XPS) test. The value of surface roughness was the highest in the anodized sample and $0.41{\pm}0.04\;{\mu}m$. The results of the SEM observation show that oxide layers of the multi porosity in the anodized sample were piled up on another, and hydroxyapatite crystal was precipitate from the surface of the hydrothermal treated sample. In the XPS analysis, O, Nb, C peak and small amounts of N peak were found in the polished specimens while Ca and P peak in addition to O, Nb, C and peak were observed in the hydrothermal treated sample.

Zr 함량 변화에 따른 Zr-xZr계 타이타늄 합금의 특성 평가

원대희,윤동주,박영준,김양수,김병일 대한치과재료학회 2011 대한치과재료학회지 Vol.38 No.2

This study was purposed to develop a titanium alloy with low elastic modulus to be used as dental implant. The new titanium alloy was prepared as a binary alloy system by adding varying content of zirconium (Zr) into the Ti-XZr system alloy. For designing the new titanium alloy, two physical variables of bond order (Bo) and d-electron orbit energy level (Md) were varied. The mean bond order (B_o) was around 2.7931~2.8098, and the mean d-electron orbit energy level (M_d ) was 2.4522~2.4795. The elastic modulus of the developed titanium alloy was 106.02~115.71 GPa. In the results of X-ray diffraction analysis, α-phase was observed in all the specimens. In TEM analysis, additional feature was identified for Ti-12Zr alloy in addition to the α-phase. The deformation twinning was observed in Ti-12Zr alloy.

마그네슘 판재 연마장치 개발

원대희,이문수,손수지 한국기계기술학회 2018 한국기계기술학회지 Vol.20 No.5

In this study, attention has been focused on magnesium materials, which are widely used for lightening of electronic products and mobile phones. Therefore, a polishing apparatus was fabricated by replacing the SiC abrasive used for polished surface of magnesium plate with a ceramic abrasive. The following conclusions were obtained. It is believed that the increase in productivity of 50% compared to the conventional cross-sectional polishing due to the double-side polishing of magnesium sheet can contribute to increase the company's sales. The surface roughness was measured by polishing the plate using a magnesium plate mirror polisher. The Ra, Rmax and Rz values were 0.43, 0.54 and 0.54, respectively. In this study, the optimum polishing speed was 800 m/s when the surface was polished with a magnesium surface polishing device designed and manufactured as a prototype.

열가압 성혈 글라스 세라믹의 파괴인성에 미치는 반복 열가압 성형의 영향

원대희 大韓齒科器材學會 2002 대한치과재료학회지 Vol.29 No.4

This study was performed to evaluate the effects of repeating the heat pressing procedure on the fracture toughness of heat-pressable glass-ceramics. Three commercially available ingots of Authentic(Ceramay GmbH), Empress and Empress 2(deutsche Ivoclar Dental GmbH) were used. Crystal phases of these glass-ceramics were investigated by means of X-ray diffraction analysis (XRD) and morphology and microstructure were studied using scanning electron microscopy (SEM). Fracture toughness was calculated using the length of radial crack formed on the Vickers-produced indentation crack by means of the indentation fracture method. According to the result of X-ray diffraction analysis, the test groups of Authentic and Empress did not show the change in crystal peak intensity, but the test group of Empress 2 showed increase in crystal peak intensity after repeating the heat pressing procedure. Fracture toughness values of the test groups of Authentic and Empress showed the aspect of increase after repeating the heat processing procedure but that of Empress 2 group showed decrease.

양극산화와 열수처리한 순수 니오비움 금속의 생체활성 평가

원대희,최운재,이민호,배태성 대한치과기공학회 2005 대한치과기공학회지 Vol.27 No.1

This study was performed to investigate the surface properties of electrochemically oxidized pure niobium by anodic oxide and hydrothermal treatment technique. Niobium specimens of 10 10 in dimension were polished sequentially from #600, #800, #1000 emery paper. The surface pure niobium specimens were anodized in an electrolytic solution that was dissolved calcium and phosphate in water. The electrolytic voltage was set in the range of 250 V and the current density was 10 / . The specimen was hydrothermal treated in high-pressure steam at 300 for 2 hours using an autoclave. Then, specimens were immersed in the Hanks' solution with pH 7.4 at 37 for 30 days. The surface of specimen was characterized by scanning electron microscope(SEM), energy dispersive X-ray microanalysis(EDX), potentiostat/galvanostat test, and cytotoxicity test. The results obtained was summarized as follows; According to the result of measuring corrosion behavior at 0.9% NaCl, corrosion resistance was improved more specimens treated with anodic oxide than in hydrothermal treated ones. The multi-porous oxide layer on surface treated through anodic oxidation showed a structure that fine pores overlap one another, and the early precipitation of apatite was observed on the surface of hydrothermal treated samples. According to the result of EDX after 30 days deposition in Hanks solution, Ca/P was 1.69 in hydrothermal treated specimens. In MTT test, specimens treated through anodic oxidation and hydrothermal treated ones showed spectrophotometer similar to that of the control group. Thus no significant difference in cytotoxicity was observed (P>0.05).

클래드 재료에 대한 열전도도 측정

원대희,박영상 한국기계기술학회 2017 한국기계기술학회 학술대회논문집 Vol.2017 No.04

In this study, cladding materials were prepared by explosion pressure welding of materials with different thermal conductivity to fabricate heating block for 3D printing. The following conclusions were obtained as a result of measuring the thermal conductivity of the clad material. Experimental results show that the lowest thermal conductivity of aluminum and titanium is 116.3 ± 0.4 W / mK.

굴림석 제작을 위한 석재 컷팅기 개발

원대희 한국기계기술학회 2016 한국기계기술학회 학술대회논문집 Vol.2016 No.05

The purpose of this study was produced after the design of new equipment in order to cut the stone roll prototype. The newly designed equipment is designed and manufactured to be dressed in rolls automatically through the use of a conveyor belt. The introduction of new stone cutters were expected to be achieved productivity improvements of 15% compared to conventional production methods.

굴림석 자동화 시스템 개발

원대희 한국기계기술학회 2016 한국기계기술학회지 Vol.18 No.6

이 글은 『신인철학』을 중심으로 이돈화의 우주관과 인간관의 중심 내용을 서술하면서 그것이 지닌 동서철학 융합적 특징을 규명하고 생명철학적 의의를 밝힘을 목적으로 한다. 우주에 관한 논의에서 이돈화는 한울이 내재적인 동시에 초월적이라는 동학의 사유 전통을 계승했다. 즉 그는 한울이 그 자체로는 시공간을 초월한 존재이지만, 시공간 안에서 역동적인 운동을 한다고 생각했다. 이런 관념은 가까이로는 19세기 동학에 뿌리를 둔 것이지만, 멀리로는 동양의 사유전통을 계승한 것이다. 이렇게 이돈화는 동양의 생명론을 기반으로 하지만, 동시에 베르그손의 생명철학을 비롯해 일본의 실재론, 스피노자의 능산적 자연 개념, 진화론 등을 선택적으로 수용해 그 내용을 풍부하게 만들었다. 한편 인간에 관한 논의에서 이돈화는 우주적 존재로서 인간이 갖는 의미를 부각시켜, 인간격(人間格)이라는 새로운 개념을 제시했다. 인간격이란 우주적 존재로서의 인간의 이상적 인격이라 정의되는데, 그는 이 개념을 통해 인간이 우주의 중추적 존재로서 무궁히 진화하면서도, 다른 자연존재들과 유기적으로 연계되어 있음을 강조했다. 이 인간격 개념 역시 기본적으로는 동학의 인내천(人乃天) 사상 및 유학의 인간관에 뿌리를 두고 있지만, 동시에 그것은 서구 근대의 진화론과 베르그손의 생명철학에서 몇 가지 중요한 사상을 흡수해 그 내용을 더욱 충실히 한 것이라 할 수 있다. 이돈화의 우주관과 인간관에 보이는 동서철학 융합적 경향은 동서철학에 대한 비판적 계승 혹은 수용이라는 균형감 있는 태도를 견지하고 있다는 점에서 의의를 지닌다. 또한 19세기 동학과는 달리, 그의 철학은 생명에 관한 서양학문의 성과를 적극 흡수해 인내천 사상을 더욱 풍부하게 했다는 데 의의가 있다. 다만 19세기 동학이 지녔던 생명의 자연 내재성에 대한 강조 및 자연 경외의 정신이 다소 약화된 점은 아쉽다. This study has as an objective to narrate the key contents of Lee Don-hwa’s (李敦化, 1884-unkown) views of the universe and human beings, to investigate the characteristics of integrated Eastern and Western philosophies, and to define their meanings in terms of philosophy of life, focusing on “New Human Philosophy (新人哲學).” In his discussion on the universe, Lee Don-hwa inherited the speculative tradition of Donghak (東學) in which “Hanul” was inherent and at the same time transcendental. Namely, he believed that Heaven itself was an existence surpassing time and space, but within that time and space, it moved dynamically. This view was based on the 19th-century Donghak at the nearest, but in a broader sense it inherited the speculative tradition of the Orient. Lee Don-hwa based his views on philosophy of life of the Orient, but at the same time selectively embraced Henri Bergson’s philosophy of life as well as Japans’ Realism, Spinoza’s concept of natura naturans, the evolution theory, etc. to make the content abundant. On the other hand, in his discussion on human beings, Lee Don-hwa proposed a new concept, “Ingangyeok (man's personality, 人間格)” by highlighting the meaning man can have as an universal existence. Ingangyeok is defined as an ideal personality of human beings as a universal existence, and through this concept, man evolves infinitely as the pivotal existence of the universe while stressing man is organically connected with other natural existences. The concept of Ingangyeok is basically based on Donghak’s doctrine of “Innaecheon (humans are Heaven, 人乃天)” and Confucian views on human beings, but Lee substantiated the content by absorbing several key ideologies from the evolution theory of the modern West and Bergson’s philosophy of life. The tendency of integrated Eastern and Western philosophies which Lee Don-hwa showed in his views on the universe and human beings is meaningful in that he adhered to balanced attitude in terms of critical inheritance or acceptance. Also, unlike the 19th-century Donghak, his philosophy actively absorbed achievements of Western learning on life and is significant in that he substantiated the ideology of Innaecheon. Only it is somewhat regrettable that it made an emphasis on the natural immanence of life and maintained weak respect for nature.

열교환법을 이용한 양자점 합성

원대희,황선태,이영기 한국기계기술학회 2018 한국기계기술학회 학술대회논문집 Vol.2018 No.05

실리콘 식각 공정시 발생하는 격자결함 관찰 및 제거동향 연구

원대희,이주훈,김지형,염근영,이주욱,이정용,Won, Dae-Hui,Lee, Ju-Hun,Kim, Ji-Hyeong,Yeom, Geun-Yeong,Lee, Ju-Uk,Lee, Jeong-Yong 한국재료학회 1996 한국재료학회지 Vol.6 No.5

차세대 소자고립구조로서 연구되고 있는 trench isolation 공정 등에는 실리콘 식각이 요구되며 실리콘 식각 공정중에는 반응성 이온에 의해 격자결함이 발생할 수 있다. 이와같이 생성된 결함은 소자의 전기적 성질을 열화시키므로 열처리를 통하여 제거하여야만 한다. 따라서 본 연구에서는 Ar,Ar/H2 플라즈마로 격자결함을 인위적으로 발생시켜 20$0^{\circ}C$-110$0^{\circ}C$ 질소분위기에서 30분간 열처리에 따른 생성된 격자결함의 소거거동을 관찰하였다. 실리콘 표면에 Schottky 다이오드를 제작하여 I-V, C-V 특성을 측정하므로써 잔류하는 전기적인 손상의 정도를 평가하였다. Ar으로 식각한 경우에는 110$0^{\circ}C$ 30분간 열처리한 결과 모든 격자결함이 제거되나 Ar/H2로 식각한 경우에는 격자결함이 완전히 제거되지 않고 (111)적층결함이 남아있었다.