액상소결한 탄화규소의 집합조직 발달에 관한 연구

성한규,조경식,박노진,최헌진,이준근 한국세라믹학회 2000 한국세라믹학회지 Vol.37 No.4

Development of texture in SiC materials by hot-pressing and subsequent annealing was studied. Crystallographic texture type was characterized by measuring X-ray pole figures on the perpendicular plane to the hot-pressing direction. Observed all pole figures were nearly axially symmetric (fiber texture). In case of ${\beta}$-SiC materials, the pole density of basal plane (0004) increased as annealing time increased, in contrast, other planes (hkil) of ${\beta}$-SiC materials and all planes of ${\alpha}$-SiC materials nearly remained unchanged. In the case of ${\beta}$-SiC materials, therefore, a weak texture of (0001) plane at the normal direction took place in the 8h annealed samples, resulting from grian growth. The fracture toughness values of ${\alpha}$-SiC materials measured in both planes parallel and perpendicular to the hot-pressing direction were very similar. However, the fracture toughness of ${\beta}$-SiC materials measured parallel to the hot-pressing direction were higher than that measured perpendicular to the hot-pressing derection, relatively, because of the texture and the microstructure anisotropy.

역산법에 의한 핀 접촉 문제의 유한 요소 해석 ( Finite Element Analysis of Pin Contact Problems Using An Inverse Method )

성한규,임장근 대한기계학회 1996 대한기계학회 춘추학술대회 Vol.- No.-

Magnetic Properties of Vanadium-Doped Silicon Carbide Nanowires

성한규,박태언,이광렬,박재관,이승철,최헌진 대한금속·재료학회 2009 METALS AND MATERIALS International Vol.15 No.1

This study reports the magnetic properties of vanadium (V) doped single crystalline silicon carbide nanowires. The first principle calculation indicated that the V-doped cubic SiC phase can exhibit half-metallic ferromagnetic properties that are essential for the realization of spintronic devices. Based on this calculation, V-doped SiC nanowires were fabricated in a chemical vapor deposition process. The single crystalline β-SiC nanowires, which are doped with ca. 4 at.% of V, had diameters of < 100 nm and a length of several μm. High-resolution transmission electron microscopy observations revealed vanadium carbide (VC) phases in the nanowires, even at this low concentration of dopants. Magnetic characterization implies that the nanowires are a mixture of the diamagnetic phase of VC and ferro- or paramagnetic phases of V-doped SiC. These results suggest that the doping of transition metal having high solubility to the SiC phase can lead to the realization of dilute magnetic semiconductor behavior at very low temperature. This study reports the magnetic properties of vanadium (V) doped single crystalline silicon carbide nanowires. The first principle calculation indicated that the V-doped cubic SiC phase can exhibit half-metallic ferromagnetic properties that are essential for the realization of spintronic devices. Based on this calculation, V-doped SiC nanowires were fabricated in a chemical vapor deposition process. The single crystalline β-SiC nanowires, which are doped with ca. 4 at.% of V, had diameters of < 100 nm and a length of several μm. High-resolution transmission electron microscopy observations revealed vanadium carbide (VC) phases in the nanowires, even at this low concentration of dopants. Magnetic characterization implies that the nanowires are a mixture of the diamagnetic phase of VC and ferro- or paramagnetic phases of V-doped SiC. These results suggest that the doping of transition metal having high solubility to the SiC phase can lead to the realization of dilute magnetic semiconductor behavior at very low temperature.

Electrochemical Characteristics of Single Crystalline Nanowires and Their Driven Mechanism

성한규,김명하,최용진,박재관,최헌진 대한금속·재료학회 2008 METALS AND MATERIALS International Vol.14 No.4

The electrochemical characteristics of single crystalline SnO₂, ZnO and Si nanowires and their driven mechanism are reported as nanostructural anode materials. As intercalation and deintercalation of Li, Si nanowires are converted to amorphous phases of shorter wire shapes caused by the lattice expansion of the single crystalline Si, resulting in the fading of discharge capacity, although the reversible capacity (2500 mAh/g) in the first cycle is very high. However, oxide nanowires (SnO₂ and ZnO) are transformed from a single crystalline structure into a polycrystalline form consisting of nano-sized metallic particles and Li₂O crystals within the wires, which maintain their discharge capacity. The results of this study imply that the large surface area and high electrochemical activity of nanowires and nano-sized polycrystalline particles can provide a method to develop a new class of one-dimensional anode nanostructures in lithium-ion rechargeable batteries.

Self Growth of Silica Nanowires on a Si/SiO2 Substrate

정한나,성한규,최헌진 한국세라믹학회 2008 한국세라믹학회지 Vol.45 No.3

The growth of amorphous silica nanowires by on-site feeding of silicon and oxygen is reported. The nanowires were grown on anickel-coated oxidized silicon substrate without external silicon or oxygen sources. Transmision electron microscopy observati onrevealed that the nanowires, which have diameters of less than 50 nm and a length of several micrometers, were grown using atraditional vapor-liquid-solid mechanism. Blue photoluminescence was observed from these nanowires at room temperature. Anapproach to grow nanowires without external precursors may be useful when integrating nanowires into devices structures. Thiscan benefit the fabrication of nanowire-based nanodevices.

R&D 프로젝트 성과의 경제적 가치 측정 모델 연구

김영명 ( Young Myoung Kim ),성한규 ( Hank Yu Sung ) 기술경영경제학회 2013 Journal of Technology Innovation Vol.21 No.1

본 연구의 목적은 연구개발(R&D) 프로젝트의 성과를 재무적 가치로 측정하기 위한 모델을 제안하는 것이다. 이를 위해 선행 연구를 통해 연구개발 프로젝트 성과를 측정할 수 있는 지표를 추출하고, 그 측정 방법을 제시하였다. R&D 성과를 재무적 가치로 환산하려는 일부 시도가 있었으나 전문가 평가, 예상 매출액, 미래시장 점유율, 할인율, 순현재가치, 실물옵션 접근법 등 주관적 의견과 과도한 예측으로 측정결과에 대한 의문이 제기되었다. 이러한 문제점을 보완하고 다양한 각도에서 재무적 가치로 평가가 가능한 모델을 제안하고자 한다. 개발된 모델을 국내 IT 기업의 실제 사례를 통하여 검증을 실시하여 신뢰성을 높였기 때문에 추후 기업의 R&D 프로젝트에 대한 경제적 평가에 새로운 전기를 마련할 수 있을것으로 기대된다. The aim for this study is to suggest a practical model to measure the financial values of the achievements from corporate research and development(R&D) projects. Performance indicators for R&D projects were identified from the extensive literature reviews and the evaluation methods to convert them into financial values were proposed to overcome the problems of excessive predictions and subjective expert assessments in existing methods. The proposed model was applied to R&D projects of an IT company in Korea for its validity test. The model is expected to be a turning point in economic evaluation of corporate R&D projects in general due to its practical and reasonable scheme.

포토리소그래피 (Photo-lithography) 기술을 이용한 대면적 나노와이어 전극 제작 및 GaN 나노와이어의 전기적인 특성연구

이승용,이상권,김태홍,성한규,최헌진 한국물리학회 2006 새물리 Vol.52 No.5

We report simple techniques for extracting the electrical properties of 1-dimensional semiconductor nanowires using conventional standard photo-lithography instead of e-beam lithography (EBL), which is a commonly used technique for the fabrication of nanoscale electrical devices. For the electrical transport measurement, the gallium nitride nanowires (GaNNWs) were prepared by using a horizontal hot-wall chemical vapor deposition (CVD), and the GaN nanowire field-effect-transistor (FET) structures on SiO$_2$/Si wafers were fabricated by using ordinary 2-mask photolithography processes. The carrier mobility estimated from the gate-modulation characteristics iwas on the order of 60 $\sim$ 70 cm$^2$/Vs. We found that our approach was a powerful technique for extracting the electrical properties from many semiconductor nanowires The material characteristics of the GaN nanowires is also discussed. 본 논문에서는 포토리소그래피 공정기술을 이용하여 대면적으로 나노와이어를 제작하기위한 기술을 소개하였으며 이를 이용하여 일차원적인 gallium nitride (GaN) 나노와이어의 전기적인 특성을 쉽게 측정할 수 있는 방법을 연구하였다. 화학기상증착 (CVD) 방법으로 합성된 GaN 나노와이어는 2단계 포토리소그래피 공정으로 Back-gate 전계효과트랜지스터 (field-effect transistor) 구조의 형태로 제작되었으며 gate modulation 특성에 의해 도출해낸 GaN 나노와이어의 캐리어 이동도는 60 $\sim$ 70 cm$^2$/Vs 로 분포되었다. 본 실험을 통하여 쉽게 적은 비용으로 많은 양의 GaN 나노와이어의 전기적인 특성과 분포를 파악할 수 있음을 확인할 수 있었으며 추가로 성장된 GaN 나노와이어의 재료적인 특성에 대해서도 논의하였다.

[SESSION 2B 실태및 관리(Ⅱ)(배출계수와 오염도)]2B4) 한국에서 최근 9년간 PM10 농도 연 변화

이석조,박일수,김상균,이재범,이동원,유철,성한규,이정영 한국대기환경학회 2004 한국대기환경학회 학술대회논문집 Vol.- No.-

실감형 텔레프레즌스 및 원격협업 서비스를 위한 요구사항

허성필(Sung-Phil Heo),황인석(Insuk Hwang),성한규(Hankyu Sung),김영재(Young-Jae Kim),최은호(Eun-Ho Choi) 한국통신학회 2009 한국통신학회 학술대회논문집 Vol.2009 No.6

지역 대기질 측정망에 나타난 국내 대기오염도의 최근 동향 : 2002년 고농도 사례 및 그 기상 특징 High Air Pollution Concentration Episodes and Their Meteorological Characteristics in 2002

김철희,박일수,이석조,김정수,진형아,성한규 한국대기환경학회 2004 한국대기환경학회지 Vol.20 No.2

We report the high concentration episodes for PM_(10), SO₂ NO₂ and O₃ in many urban areas Korea during 2002. The high concentration episodes are identified based on the National Ambient Air Quality Standards and the observations obtained from the Regional Air Monitoring Network composed of approximately 160 air pollution monitoring stations located in a number of major or big cities in South Korea including Seoul, Pusan, Daegu, and Incheon cities. The results show that the twenty cases of high concentration episodes in 2002 consists of both ozone warning episodes (6 cases) and high PM_(10) concentration cases (14 cases), and one half of the latter are found to occur in association with the Yellow Sand (Asian Dust) phenomena. The most outstanding characteristics of the reported episodes are the excessively high levels of maximum PM_(10) concentrations during the Yellow Sand period (i.e.. exceeding 3.000㎍/㎥ in April, 2002) and their variable occurrence frequencies across seasons. The high ozone concentration episode days are mainly resulting from both the high photochemical reactions and poor ventilations. The high PM_(10) concentration days during non Yellow Sand periods, however, mostly occurred under the influence of synoptic meteorological conditions such as stagnant or slowly passing high pressure centers, and consequently prevailing weak wind speeds over the Korean peninsula. The overall results of our study thus suggest the importance of both synoptic and local meteorological factors for high concentration levels in the major and/or big cities in Korea.