• Title/Summary/Keyword: 결정방향

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생산전략 연구의 새로운 방향

  • 김연민;이진주
    • Korean Management Science Review
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    • v.6 no.2
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    • pp.3-26
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    • 1989
  • 본 연구는 생산전략 가운데 제조전략을 중심으로, 주로 전략의 내용연구 문헌을 고찰하고, 생산전략 연구의 새로운 방향을 제시하였다. 생산전략 연구를 재검토 하기에 앞서, 먼저 경쟁전략을 개관하여 전략연구에서 생산전략이 가지는 의미와, 전략연구의 축적된 내용이 어떻게 생산전략에 활용될 수 있는가를 살펴보았다. 생산전략에 대해서는 그 정의, 경쟁차원, 전략적 의사결정 영역, "본원적 생산전략" 및 성과변수에 대한 그간의 연구를 정리, 재검토하였다. 그리고 이러한 문헌의 고찰을 통해 생산 전략 연구의 문제점과 향후 방향을 제시하였다.방향을 제시하였다.

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Effects of Pressurereduction Rate in a Sublimation Crystal Growth Furnace on the Growth of SiC Single Crystals (승화결정성장로의 감압속도가 탄화규소 단결정 성장에 미치는 영향)

  • Kim, Jong-Pyo;Kim, Yeong-Jin;Kim, Hyeong-Jun
    • Korean Journal of Crystallography
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    • v.3 no.1
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    • pp.23-30
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    • 1992
  • a-SiC crystals were grown on the (001) plane of a-SiC seed crystals by sublimation method to find effects of pressure-reduction rate of the crystal growth furnace own the growth rate and orientstion of grown SiC crystals. Pressure-reduction rate at the initial growth stage affected the crystallinity of grown SiC crystals. In case of high pressure-reduction rate, growth rate was high and 3csic polycrystalline was grown on the seed. On the other hand, low pressure-reduction rate caused the growth rate to be slow and 6H-SiC single crystal was grown on the seed. However, even after growing SiC for 2 hours under the condition in which.

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원자로 압력용기 원주방향 용접부의 가압열충격 심사기준온도의 적정성 평가

  • 장창희;정일성
    • Proceedings of the Korean Nuclear Society Conference
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    • 1998.05b
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    • pp.369-376
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    • 1998
  • 원자로 압력용기는 원자력발전소의 일차 압력경계를 구성하는 핵심 부품으로 이의 건전성은 원전의 안전성과 수명관리에 결정적인 영향을 미친다. 탄소강으로 구성된 압력용기는 노심에 근접하게 위치하여 운전중 계속되는 고속중성자 조사로 인하여 인성이 감소한다. 운전중 비상노심 냉각수가 주입되어 압력용기가 급격하게 냉각되면서 압력이 높게 유지되거나 재가압이 되는 가압열충격 현상이 발생하는 경우 조사취화된 압력용기가 적절한 안전여유를 가지지 못할 수도 있다. USNRC에서는 이에 대한 종합적인 연구결과를 바탕으로 가압열충격 규정을 제정하여 가압열충격 기준온도(RT$_{PTS}$)의 계산 방법과 심사기준온도를 제시하였다. 가압열충격 심사기준온도의 결정근거가 기술되어 있는 SECY 82-465에 의하면 축방향 용접부에 대한 위험도를 평가하여 270℉를 심사기준온도로 정하고 원주방향 용접부에 대해서는 30℉를 더하여 300℉를 심사기준온도로 제시하였다. 이 연구에서는 이렇게 제정된 원주방향 용접부에 대한 심사기준온도의 적정성을 평가하기 위하여 균열방향에 따른 가압열충격 위험도를 VISA-II 코드로 평가하였다. 우선 가압열충격 기준온도 제정 시 사용된 방법과 결과들을 검토하고 NRC의 계산결과를 재현하였다. 이를 바탕으로 원주방향 용접부에 대한 위험도를 평가한 결과 균열방향의 차이를 고려하기 위해 적용된 기술적 여유도인 30℉는 과도한 보수성을 내포하고 있음을 알 수 있었다. 원주방향 용접부가 축방향 용접부와 동일한 수준의 가압열충격 위험도를 가지기 위한 심사기준온도 차이는 50℉ 이상인 것으로 평가되었다.을 수 있었다.ngineering because this field has large uncertainties on predicting the effect of earthquake on structures. This paper is based on the presented paper at the Bertero Symposium held in January 31an4 February 1 at Berkeley, California, USA which was entitled "Needs to Evaluate Real Seismic Performance of Buildings-Lessons from 1995 Hyogoken-Nambu Earthquake-". The lessons for buildings from the damage due to the Hyogoken-Nambu Earthquake are necessity to develop more rational seismic design codes based upon a performance-based design concept, and to evaluate seismic performance of existing buildings. In my keynote lecture at the Korean Association for Computational Structural Engineering, the history of seismic design and use of structural analysis in Japan, the lessons for buildings from

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Evaluation of Axial Buckling Effect in On-Line Axial Power Shape Synthesis (실시간 노심출력분포 합성에서의 축방향 경계조건 영향평가)

  • In, Wang-Kee;Kim, Joon-Sung;Yoon, Tae-Young;Auh, Geun-Sun;Kim, Hee-Cheol
    • Nuclear Engineering and Technology
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    • v.25 no.1
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    • pp.148-153
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    • 1993
  • A fifth-order Fourier series technique is applied in Core Operating Limit Supervisory System (COLSS) to construct the on-line core average axial power shape from in-core detector signals because of its simplicity and fast computation. Such a synthesizing accuracy depends on number of Fourier series modes and axial boundary conditions. COLSS currently uses the five-mode Fourier series technique which utilizes the five axially located fixed in-core detector signals and a constant axial boundary condition. Therefore, the constant axial boundary condition should be appropriately chosen based on the evaluation of its effect on the accuracy of the on-line calculations. The four cases of axial buckling (0.75, 0.8, 0.9 and 1.0) were examined for Yonggwang Nuclear Units 3&4 as the axial boundary conditions in this paper. The core average axial power shapes and the operating margins were compared for each case to determine the optimal constant axial buckling. The axial buckling of 0.9 was found to be the optimal value.

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그룹의사결정지원을 위한 인터넷 기능개선 방향

  • Heo, Yeong-Jong
    • Asia pacific journal of information systems
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    • v.6 no.2
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    • pp.107-124
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    • 1996
  • This research studied future directions of Internet technology toward supporting group decision making. From the previous research, this study classified requirements of group decision support systems into three categories which are information transfer, information provision, and communication control. For each of the category, this study analyzed the limits of current Internet functions. Next, this research discussed technological solutions, for each of the OSI 7 layers, toward supporting group decision making. Additional functions in Internet which are required for group supporting are tracing communications, application dependent coding, selection of communication modes, and security handling. For high speed data communication in Internet, this research discussed the potential of cell-switching technology for the lower level link in Internet. The conclusions of this research can be used for designing future group decision support systems and development of Internet.

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기체 속도 제어를 통한 MOCVD법을 이용한 $Bi_2Te_3$ 열전 필름 성장

  • Yu, Hyeon-U;Jeong, Gyu-Ho;Choe, Won-Cheol;Kim, Hyo-Jeong;Park, Chan;Kim, Jin-Sang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2010.06a
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    • pp.230-230
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    • 2010
  • 본 연구에서는 개조된 MOCVD법을 이용하여 (100) GaAs 기판 위에 나노 구조 $Bi_2Te_3$ 열전 필름을 성장시켰다. 기존의 MOCVD법과 달리 서셉터의 모양을 변화시켜 기체상태에서 $Bi_2Te_3$ 나노파티클의 형성과 기판위에서 성장을 유도 하였다. 또한 서셉터의 노즐의 면적을 변화시켜 기체의 속도를 제어함에 따라 $Bi_2Te_3$ 필름을 형성시켰다. 서셉터의 모양의 변화에 따라 기체 상태에서 $Bi_2Te_3$ 나노파티클을 형성하고 이를 기판위에서 성장시켜 $Bi_2Te_3$ 열전 필름의 결정립계를 조절할 수 있었고, 또한 노즐의 면적의 변화에 따른 기체의 속도를 제어하여 $Bi_2Te_3$ 결정립계 및 결정 배향 방향을 조절 하였다. 본 연구결과에서는 MOCVD 반응관의 서셉터의 모양 및 노즐의 면적의 변화에 따라 결정립계 및 결정 성장방향이 조절될 수 있음을 확인하였고 이러한 변화에 따라 열전도도를 제어하여 열전성능지수의 향상을 기대 할 수 있다.

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A numerical study on the effects of the asymmetric cusp magnetic field in 8 inch silicon single crystal growth by Czochralski method (초크랄스키법에 의한 8인치 실리콘 단결정 성장시 비대칭 커스프자장의 영향에 관한 연구)

  • 이승철;정형태;윤종규
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.6 no.1
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    • pp.1-10
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    • 1996
  • A numerical study was conducted on the effects of the cusp magnetic field in 8" silicon single crystal grwoth by Czochralski method. For a damping effects simulation by magnetic field, low reynolds number ${\kappa} - {\varepsilon}$ model was adopted. Symmetrci cusp magnetic field has a effect of damping streamline crystal, is lowerd with the increasing cusp magnetic field intensity. The uniformity of the oxygen concentration was improved. The asymmetirc cusp magnetic field increased the oxygen concentration however, oxygen concentration distribution in the radial direction was remained uniform. Suitable combination of symmetric and asymmetric cusp magnetic fields could give uniform and low oxygen concentration in the axial direction.tion.

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Growth of zincite(ZnO) single crystal by hydrothermal method (수열법에 의한 산화아연(ZnO) 단결정 성장)

  • 이영국;유영문
    • Korean Journal of Crystallography
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    • v.7 no.2
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    • pp.183-190
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    • 1996
  • Single crystals of ZnO were grown hydrothermally with KOH solution in silver lined autoclave. The effect of LiOH and NH4OH on the morphology of as-grown crystals was studied. As-grown crystals were pale green and the maximum size was 30×30×20mm3. Addition of LiOH reduced the density of flaws on the (0001) face of as-grown ZnO crystals. In highly concentrated KOH solution, ZnO had a strong tendency to grow along the c-axis. When 1.0-2.0 M of NH4OH was added into mineralizer, growth rate along the direction of a-axis increased. From this result, ZnO single crystals of equant-faced hexagonal prism could be grown with acicular seeds.

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Microstructure of GaN films on sapphire surfaces with various orientations (사파이어 기판 방향성에 따른 GaN 박막의 미세구조)

  • 김유택
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.9 no.2
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    • pp.162-167
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    • 1999
  • GaN epilayers deposited by the OMVPE method on sapphires with 3 different surface orientations were investigated by TEM and their difference in mucrostructure were compared with each other. GaN epilayers were grown on the all three kinds of sapphire substrates; however, the best interfacial state and crystallinity were observed in the specimen using a {0001} substrate The density of defects in GaN epilayers on {0001} substrates was also less than others. No buffer layer was found at the interfaces of all the specimens; however, it was observed that the region which shows lattice distortion at the interface was only a few nonameter wide. Accordingly, TEM investigation revealed that GaN epilayers having some internal defects could be grown on sapphire {1120} and {1102} planes without a buffer layer, and the hetero-epitaxial GaN films were obtained from the specimen using {0001} substrates with the microstructural point of view.

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Edge Based Dynamic Brush Stroke Generation for Painterly Rendering (회화적 렌더링을 위한 에지 기반 동적 브러시 스트로크 생성에 관한 연구)

  • Park Youngsup;Yoon Kyunghyun
    • Journal of Korea Multimedia Society
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    • v.8 no.2
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    • pp.164-173
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    • 2005
  • Painterly rendering may bring various results through the parameters that determine the characteristics of brush strokes such as, color, orientation, size, and shape. In this paper, we propose the most adaptive brush stroke generation for source images, using reference data. Our algorithm used Colors formed by actual palette colors from artists. To create the palette, we have referred mostly to colors used in Van Gogh's works and determined the color of brush strokes by transferring it to the most similar one, through comparing colors used in source images and the palette colors. Also, In order to emulate a brush stroke with dynamic properties like Van Gogh styles we have applied a brush stroke orientation that surrounds the edges by referring to the edge orientation of source images. The sizes were determined depending on the different sizes of the objects from wide to narrow brushes. Finally, we applied spline curve shapes to simulate curves and swirls like Van Gogh styles. The brush strokes created in such method, were applied separately according to its segmented images, and composed after rendering.

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