• Title/Summary/Keyword: transition-edge

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Optical properties of InxGa1-xN/GaN epilayers (InxGa1-xN/GaN 박막의 광학적 특성)

  • Jun, Yong-Ki;Chung, Sang-Jo
    • Korean Journal of Materials Research
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    • v.12 no.1
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    • pp.54-57
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    • 2002
  • We have grown undoped $In_ xGa_{1-x}N,\; In_xGa_{1-x}N:Si\;and\;In_{0.1}Ga_{0.9}N:Zn$ thin films by MOCVD at temperature between 880 and $710^{\circ}C which endows various In composition in the epilayer from 0.07 to 0.22 as examined using X-ray diffraction, optical absorption(OA), photocurrent (PC) and photoluminescence (PL). The In molar fraction estimated from PL results is higher than that from the OA, PC, and X-ray data for $X{\le}0.22$, which may be caused by phase separation. However, the In molar fraction estimated by X-ray diffraction, OA, PC and PL for $In_xGa_{1-x}N:Si$ does not show discrepancy. With the appropriate Zn doping in undoped $In_{0.1}Ga_{0.9}N$, the emission peak is shifted from 3.15 eV which originates from the band edge emission peak to 2.65 eV which resulted from the conduction band to acceptor transition due to a deep acceptor level.

An study on the Space Composition of the Theme Park-style Shopping Center - Focused on Designed Projects by Jerde Partnership - (테마파크 형 쇼핑센터의 공간구성에 관한 연구 - 저드파트너쉽의 설계 작품을 중심으로 -)

  • Ha, Sung-Joo
    • Korean Institute of Interior Design Journal
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    • v.16 no.6
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    • pp.144-151
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    • 2007
  • The idea of shopping is changed from a purchase of merchandise to an experience of pleasure. This study is a space composition analysis for the introduction of theme in multi-plex shopping center design to reflect variable consumer trend and company marketing strategy, The study progressed through theoretical consideration and substance analysis about the shopping centers which had been designed by Jerd Partnership In Japan since 2000. The following is result. The path is a sole main street that is made of curve form, parallel and vertical circulating rout and movement of human being. It leads continuity. The node and landmarks have a circular court with typifier as powerful center, character of transition space and event for experience. It makes locational quality. The districts are composed of retail shops, restaurants and culture facilities and the edge is represented by closed vertical wall and parapet. It induces a domain. The characteristic of Jerde shopping center is an experience of theme environment through the path as betweenness with a story based on a main theme. It is mostly related nature or exotic element and is obviously represented at path and node. The node takes a round shape and bring about event as a court. The application of theme to the shopping center by Jerde has a significant meaning for place marketing.

An study on the Expressive Characteristics of Jerde Partnership's shopping center - Focused on Space Composition of Theme Park-style - (저드파트너쉽 쇼핑센터의 표현 특성에 관한 연구 - 테마파크형 공간구성을 중심으로 -)

  • Ha, Sung-Joo;Ha, Mi-Kyoung
    • Proceedings of the Korean Institute of Interior Design Conference
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    • 2007.11a
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    • pp.103-106
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    • 2007
  • The idea of shopping is changed from a purchase of merchandise to an experience of pleasure. This study is a space composition analysis for the introduction of theme in multi-plex shopping center design to reflect variable consumer trend and company marketing strategy. The study progressed through theoretical consideration and substance analysis about the shopping centers which had been designed by Jerd Partnership from 2000 in Japan. The following is result. The path is a sole main street that is made of curve form, parallel and vertical circulating rout and movement of human being. It leads continuity. The node and landmarks have a circular court with typifier as powerful center, character of transition space and event for experience. It makes locational quality. The districts are composed of retail shops, restaurants and culture facilities and the edge is represented by closed vertical wall and parapet. It induces a domain. The characteristic of Jerde shopping center is an experience of theme environment through the path as betweenness space with a story based on a main theme.

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Photoluminescence study in GaAs/AlGaAs multi-quantum well structure by hydrogen passivation (수소화 처리에 의한 GaAs/AIGaAs 다중양자우물의 PL 연구)

  • Park, Se-Ki;Lee, Cheon;Jung, Min
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1997.11a
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    • pp.468-472
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    • 1997
  • The effect of the surface state on the quantum efficiency of underlying GaAs/AlGaAs multi-quantum well(MQW) structures consisting of three GaAs quantum wells with different thickness, is studied by low temperature photoluminescence(PL). The structure was grown by molecular beam epitaxy(MBE) on (100) GaAs substrate. The thickness of three GaAs quantum wells was 3, 6 and 9 nm, respectively. The MQWs were placed apart from 50 nm AlGaAs edge-barriers including two inner-barriers with 15 nm in thickness. The samples used in this study were prepared with different growth temperatures. Particularly, the hydrogen passivation effect to the 9 nm quantum well located at near surface appeared much stronger than any others. Transition energy and optical gain related to the hydrogen passivation effects on the multi-quantum well structure was calculated by transfer matrix method.

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Intake Flow Characteristics of HyShot Scramjet Engine (HyShot 스크램제트 엔진의 흡입구 유동특성 연구)

  • Won Su-Hee;Choi Jeong-Yeol;Jeung In-Seuck
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2004.10a
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    • pp.47-52
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    • 2004
  • In the design of scramjet intake for hypersonic flight, a variety of aerothermodynamics phenomena are encountered. These phenomena include blunt leading - edge effects, boundary layer development issues, transition, inviscid / viscous coupling, shock - shock interactions, shock / boundary - layer interactions, and flow profile effects. For intakes that are designed to operate within a narrow Mach number / altitude envelope, an understanding of a few of these phenomena might be required. In this work several predominant flowfield phenomena (viscous phenomena, boundary - layer separation, and combustor entrance profile) are discussed to investigate the performance of the intake at the altitude and angle of attack extremes of the HyShot flight experiment.

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Pneumatics (Air powered) Training as an Exercise Paradigm Shift (운동패러다임 변화로서의 공압 트레이닝)

  • Lee, Woon-Yong;Hong, Sang-Min
    • Journal of Wellness
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    • v.7 no.4
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    • pp.187-199
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    • 2012
  • The purpose of this review was to introduce a new training concept as pneumatic training method and how to apply the principles. Uses the new resistance, especially air powered that invisible, intangible, along with training on how to contribute to broadening their horizons, while attempts have been passed. Provide transition training methods in accordance with the trend of the times, and why these changes may be in the form of outside-free for theoretical consideration. From weight resistance, hydraulic, isokinetic exercise, and to pneumatic training why justification should apply for these training methods are presented also suggested the superiority of pneumatic training. In the near future, newly developed training method will be appear. In conclusion, it will be contribute to sports by concerning and applications to cutting edge training

Mn K-Edge XAS Analyses of $Zn_{2-x}Mn_xSiO_4$ Phosphors ($Zn_{2-x}Mn_xSiO_4$ 형광체의 망간 K 흡수단 엑스선 흡수 분광 분석)

  • Choi, Yong Gyu;Lim, Dong Sung;Kim, Kyong Hon;Sohn, Kee Sun;Park, Hee Dong
    • Journal of the Korean Chemical Society
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    • v.43 no.6
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    • pp.636-643
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    • 1999
  • Green-emission intensity of a $Zn_{2-x}Mn_xSiO_4$ phosphor, which is a potential candidate as a green component in PDP device, significantly increases provided that the compound is additionally heat treated at 900$^{\circ}C$ after solid state reaction at 1300$^{\circ}C$. In order to verify origin of such an intensity enhancement after the additional heat treatment in association with the electronic and local structural change at around Mn ions, the Mn K-edge X-ray absorption spectra were recorded. From the analyses of the preedge peak corresponding to $1s{\rightarrow}3d$ bound state transition and XANES spectrum, it is known that most Mn ions are in +2 oxidation state and substitute Zn ion site regardless of the thermal treatment. In addition, EXAFS analyses revealed that Mn ions formed $MnO_4$ tetrahedra with the Mn-O bond length shortened by 0.01${\AA}$ and with reduced Debye-Waller factor in the thermally treated sample.

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Ecological Characteristics Analysis and Management Plan of Freshwater Lake Basin - A Case Study on Duryang Reservoir at Sacheon - (담수호소 유역 수변의 생태적 특성과 관리방안 연구 - 사천시 두량저수지를 사례로 -)

  • Lee, Soo-Dong;Kim, Sang-Bum
    • Journal of the Korean Institute of Landscape Architecture
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    • v.37 no.1
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    • pp.50-64
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    • 2009
  • The freshwater lakes located at the fringe of urban cities are a habitat for diverse organisms. However, they are facing severe danger of environment deterioration and water pollution caused by reckless development of the area. In this study, an ecological management plan was suggested to promote the biodiversity through appointing management area based on the research and analysis data of flora and fauna as well as maintain biodiversity and harmonize utilization of freshwater lakes such as Duryang Reservoir at Sacheon, Gyeongsangnam-do. Base on the data of ecological research and analysis, this study conducted research on biotope assessment, wild life habitat assessment and presence of protected species. As a result, the ecosystem conservation area including multi-layer structured natural forests, waterside and wetland that are home to various species and the edge area with high habitat diversity were recognized as highly preservable regions. Management areas were ecologically disturbed region, highly polluted commercial district and damaged waterside caused by fishing. Proactive management must be implemented through vegetation management such as vegetation transition and shrub planting as well as establishing pollutant management system. The deterioration of waterside and forest vegetation of freshwater lake has a direct influence on biodiversity and water quality. Therefore, the conservation area and development area should be totally separated from each other, and the development area must be restored and managed strictly.

A High Performance License Plate Recognition System (고속처리 자동차 번호판 인식시스템)

  • 남기환;배철수
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.6 no.8
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    • pp.1352-1357
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    • 2002
  • This Paper describes algorithm to extract license plates in vehicle images. Conventional methods perform preprocessing on the entire vehicle image to produce the edge image and binarize it. Hough transform is applied to the binary image to find horizontal and vertical lines, and the license plate area is extracted using the characteristics of license plates. Problems with this approach are that real-time processing is not feasible due to long processing time and that the license plate area is not extracted when lighting is irregular such as at night or when the plate boundary does not show up in the image. This research uses the gray level transition characteristics of license plates to verify the digit area by examining the digit width and the level difference between the background area the digit area, and then extracts the plate area by testing the distance between the verified digits. This research solves the problem of failure in extracting the license plates due to degraded plate boundary as in the conventional methods and resolves the problem of the time requirement by processing the real time such that practical application is possible. This paper Presents a power automated license plate recognition system, which is able to read license numbers of cars, even under circumstances, which are far from ideal. In a real-life test, the percentage of rejected plates wan 13%, whereas 0.4% of the plates were misclassified. Suggestions for further improvements are given.

Study on th growth of nonlinear optical crystal $CsLiB_{6}O_{10}$ (비선형 광학 결정 $CsLiB_{6}O_{10}$ 육성에 관한 기초 연구)

  • 김호건;김명섭
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.6 no.2
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    • pp.166-176
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    • 1996
  • The fundamental conditions for growing $CsLiB_{6}O_{10}$ crystal, new nonlinear optical material, were investigated. Stoichiometirc mixture of $CsLiB_{6}O_{10}$ composition resulted in the crystal of the same composition in the process of heating at the temperature above $600^{\circ}C$. No phase transition was observed in the $CsLiB_{6}O_{10}$ crystal in the temperature range of $600^{\circ}C~800^{\circ}C$, and $CsLiB_{6}O_{10}$ crystal melted congruently at $850^{\circ}C$. When the melt of this composition was cooled at rates of $1~150^{\circ}C/hr$, glass state ingot was formed regardless of cooling rates. However, $CsLiB_{6}O_{10}$ crystals were formed directly from the melt at any cooling rate in the presence of $CsLiB_{6}O_{10}$ seed crystal in the melt. Transparent $CsLiB_{6}O_{10}$ single crystal was grown from the melt using the seed crystal at the growing rate of 0.06 mm/hr in the furnace having the temperature gradient of $100^{\circ}C/cm$. Analysis of the single crystal showed that the crystal belonged to the noncentrosymmetric tetragonal space group 142d and unit cell dimensions were $a=10.467(1)\;{\AA},\;c=8.972(1)\;{\AA}\;and\;V=983.0(2)\;{\AA}^3$. Optical absorption edge of the crystal was observed at 180mm and the crystal showed a good optical transparency (70% transmittance, sample thickness 0.5 mm) in the wide wavelength range above 300 nm.

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