• The Korean Journal of Ceramics
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• 제3권4호
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• pp.257-262
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• 1997

Aluminum nitride(AIN) thin films were deposited on SiO$_2$/Si substrates by reactive sputtering for the application of SAW devices. The major deposition parameters such as pressure, nitrogen fraction, rf power, substrate distance were changed to find out the optimal condition for c-axis oriented thin films on an amorphous substrate. The effects of deposition parameters on the crystal structure, residual stress, and growth morphology of thin films were characterized by XRD, SEM, and TEM. The FWHM of (002) rocking curve of the films deposited at the proper condition was lower than 2.2$^{\circ}$(C=0.93$^{\circ}$). Cross-sectional TEM showed that self-aligned structure was developed just after slightly random growth at the initial stage. The frequency characteristics of test device fabricated from AIN thin films confirmed their piezoelectric property and applicability for SAW devices.

• 대한기계학회논문집A
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• 제38권12호
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• pp.1317-1323
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• 2014

본 연구의 목적은 마찰교반용접된 Al7075-T651의 피로균열전파 거동에 미치는 시험편의 채취방향의 영향을 고찰하기 위한 것이다. 피로균열전파 실험은 마찰교반용접된 공시재로부터 모재와 용접재에 대하여 CT 시험편을 채취하여 일정응력확대계수범위 제어하에서 수행되었다. 균열이 용접선에 수직하여 전파하는 것(TL 시험편으로 명명)과 균열이 용접선과 나란히 전파하는 시험편(LT 시험편으로 명명)에 대하여 3가지 다른 응력확대계수범위에서 실험이 수행되었다. 시험편의 채취 방향에 따라 피로균열전파거동에 주요한 영향을 미침을 알 수 있었다. Paris 법칙에 적합시킨 결과 지수 m값은 WM-LT 시험편이 3.56으로 가장 높게 나타났다.

• 한국표면공학회지
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• 제35권1호
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• pp.33-38
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• 2002

CrN 박막이 펄스마그네트론증착법에 의하여 glass, Si(110), AISI 1040 steel 위에 증착되어졌다. 각 기판 위에 증착된 CrN 박막의 구조는 표면의 접촉특성 보다는 표면의 구조에 영향을 받는 것으로 판단되어 진다. 또한 grain의 크기는 기판에 관계없이 증착 시간이 증가함에 따라 증가한다. AISI 1040 steel 위에 증착된 CrN 박막의 grain 성장과 구조는 glass와 Si에 비하여 바이어스에 강하게 영향을 받는다. 이러한 결과는 glass 와 Si 보다도 금속이 높은 전기전도성을 가지고 있기 때문인 것으로 생각되어 진다.

• 실천공학교육논문지
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• 제11권2호
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• pp.291-303
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• 2019

본 연구의 목적은 대학생의 성취지향성목표가 대학생활만족도와 대학 소속감에 미치는 영향에 대해 분석하는 것이다. 3년에 걸친 종단 자료를 바탕으로 시간의 흐름에 따른 변화를 분석하기 위해 본 연구는 잠재성장 모형을 활용하였다. 그 결과는 성취목표지향성 개념 중 숙달접근과 숙달회피는 대학생활만족도 초기값에는 영향을 주고 있으나 시간의 흐름에 따른 변화는 없었다. 반면, 수행접근은 대학생활만족도의 초기값에 영향을 주지 못하였지만 시간이 흐름에 따른 변화율에는 긍정적인 영향을 주었다. 그리고 수행회피는 초기값과 변화율 모두 영향을 주지 못하였다. 성취목표지향성 요인들이 소속감에 미치는 영향도 조사한 결과 숙달접근과 숙달회피는 대학생활만족도에 미치는 형태와 비슷하게 소속감 초기값에도 영향을 주었다. 다만 수행접근은 대학생활만족도의 변화율에는 영향을 주었지만 소속감 초기값에는 영향을 주지 않는 것으로 나타났다.

• 한국표면공학회지
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• 제29권6호
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• pp.862-868
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• 1996

Cadmium sulfide is commonly used as the window material for thin film solar cells, and can be prepared by several techniques such as sputtering, spray pyrolysis, close spaced sublimation (CSS), thermal evaporation, solution growth methods, etc. In this study, CdS films were deposited by thermal evaporation, close spaced sublimation, and solution growth methods, respectively, and the effects of the methods on physical properties of polycrystalline CdS deposited on ITO/glass were investigated. Also, the effects of variously prepared CdS thin films on the physical properties of CdTe deposited on the CdS were investigated. The thickness of polycrystalline CdS films was maintained at $0.3\mu\textrm{m}$ except for the solution grown CdS when $0.2\mu\textrm{m}$ thick CdS was deposited. After the deposition, all the samples were annealed at $400^{\circ}C$ or $500^{\circ}C$ in H2 atmosphere. To investigate physical properties of the deposited and annealed CdS thin films, UV-VIS spectro-photometry, X-ray diffractometry (XRD), and Auger electron spectroscopy (AES), and cross sectional transmission electron microscopy(XTEM) were used to analyze grain size, crystal structure, preferred orientation, optical properties, etc. The annealed CdS showed the bandedge transition at 510nm and the optical transmittance high than 80% for all of the variously deposited films. XRD results showed that CdS thin films variously deposited and annealed had the same hexagonal structures, however, showed different preferred orientations. CSS grown CdS had [103] preferred orientation, thermally evaporated CdS had [002], and CdS grown by the solution growth had no preferred orientation. The largest grain size was obtained for the CSS grown CdS while the least grain size was obtained for the solution grown CdS. Some of the physical properties of CdTe deposited on the CdS thin film such as grain size at the junction and grain orientation were affected by the physical properties of CdS thin films.

• 한국전기전자재료학회논문지
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• 제36권1호
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• pp.74-80
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• 2023

Gallium oxide (Ga₂O₃) thin films were grown on c-, a-, m-, r-plane sapphire substrates using a mist chemical vapor deposition system. Various growth temperature range of 400~600℃ was applied for Ga₂O₃ thin film deposition. Then, several structural properties were characterized such as film thickness, crystal phase, lattice orientation, surface roughness, and optical bandgap. Under the certain growth temperature of 500℃, all grown Ga₂O₃ featured rhombohedral crystal structures and well-aligned preferred orientation to sapphire substrate. The films grown on c-and r-plane sapphire substrates, showed low surface roughness and large optical bandgap compared to those on a-and m-plane substrates. Therefore, various sapphire orientation can be potentially applicable for future Ga₂O₃-based electronics applications.

• Journal of Magnetics
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• 제19권4호
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• pp.333-339
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• 2014

Single crystal growth of $BaFe_{12}O_{19}$ by the solid state crystal growth method was attempted. Seed crystals of ${\alpha}-Fe_2O_3$ were pressed into pellets of $BaFe_{12}O_{19}$ + 2 wt% $BaCO_3$ and heat-treated at temperatures between $1150^{\circ}C$ and $1250^{\circ}C$ for up to 100 hours. Instead of single crystal growth taking place on the seed crystal, BaO diffused into the seed crystal and reacted with it to form a polycrystalline reaction layer of $BaFe_{12}O_{19}$. The microstructure, chemical composition and structure of the reaction layer were studied using scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), x-ray Diffraction (XRD) and micro-Raman scattering and confirmed to be that of $BaFe_{12}O_{19}$. XRD showed that the reaction layer shows a strong degree of orientation in the (h00)/(hk0) planes in the sample sintered at $1200^{\circ}C$. $BaFe_{12}O_{19}$ layers with a degree of orientation in the (hk0) planes could also be grown by heat-treating an ${\alpha}-Fe_2O_3$ seed crystal buried in $BaCO_3$ powder.

• The Korean Journal of Ceramics
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• 제6권2호
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• pp.116-119
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• 2000

The a-axis and c-axis prefer oriented SBT thin films could be deposited on Pt(111)/Ti/$SiO_2$$650^{\circ}C$). The c-axis preferred orientation of SBT film can be obtained by Sr deficiency and high compressive stress. However, the a-axis-oriented grains can be formed under stoichiometric Sr content and nearly stress-free state.

• 한국IT서비스학회지
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• 제15권1호
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• pp.1-18
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• 2016

Recently, in the bio-field success stories of ventures through a biosimilar technology is being excavated. but the growth of ICT industry has been stagnant since reaching a boom in the dissemination of early high-speed internet in 2000s. The purpose of this study is to explore the factors of change of business model and business strategy of ICT ventures and SMEs with the evolution of the digital ecosystem, and to drive the factors to be competitive on the global value chain. The researcher selected an entreprenuership, market-innovation orientation, technology-innovation orientation, and Administration-innovation orientation as internal factors influencing the global competence and healthiness of the ecosystem as external factors. The researcher applied samples of 94 ICT Venture and SMEs to a research model, and adopted 5 hypotheses. The researcher believes that only a few hypotheses were adopted because it takes time for overall innovation orientation of ICT Venture and SMEs to result in the real global competence as the their innovation orientation is still on the level of domestic market. And the researcher also thinks that only healthiness of the ecosystem affected management performances because the companies' performances of the last 3 years were so weak that the correlation between innovation orientation of each company and the performances were not big enough.

• The Korean Journal of Ecology
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• 제8권2호
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• pp.99-107
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• 1985

Photosynthetically Active Radiation (PAR) affects the growth of plants as well as their photosynthetic rates. A mathematical model for intercepted solar radiation on the tilted leaf with any azimuth angle was established and the leaf orientation in which receives the maximum solar radiation was determined each month, during the growing season, and for an year. PAR was maximized at the leaf elevation of 50。~60。 in the winter, at that of 20。~40。. On the whole the leaves of tilt angle 0。~40。 received much radiation comparing with those of other tilt angles. The theoretical tendencies were compared with the distribution of leaf orientation measused practically. The average leaf elevation of maple tree was 17.0。$\pm$12.0。, and that of ginkgo was 29.8。$\pm$16.0。. Several results from other literatures support our suggestion that cumulative effevct of the relationships between surface normal vector and a vector pointing in the direction of the radiation determine the leaf orientation.