• 제목/요약/키워드: basic materials

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Development of Active Matrix Cathodes Composed of a-Si:H TFTs and Gated Molybdenum Field Emitter Arrays

  • Chung, Choong-Heui;Song, Yoon-Ho;Hwang, Chi-Sun;Ahn, Seong-Deok;Kim, Bong-Chul;Cho, Young-Rae;Lee, Jin-Ho;Cho, Kyoung-Ik
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.1020-1023
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    • 2002
  • We successfully developed a-Si TFT controlled active matrix cathode (AMC) with gated Mo emitters. Also, we could remove emitter failures of the AMC through a novel surface treatment of Mo-tips, which indicates reduction of $MoO_3$ or chemical wet etching of $MoO_3$ by surface treatment. Transient behaviors of the AMC are strongly dependent on not only DC characteristics of device but also the device structure. Brightness and gray scale were well realized by low-voltage scan and data signals addressed to a-Si TFTs.

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A Comparative Study of Contents of Korean Basic Sewing Textbook (국내 기초 봉제 교재의 콘텐츠에 관한 비교 연구)

  • Kim, Sun-Young
    • Journal of the Korean Society of Costume
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    • v.62 no.3
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    • pp.73-83
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    • 2012
  • The purpose of this study is to contribute in developing guidebooks that can be used in the courses of needlework study by comparing and analyzing the contents and organizations of needlework-related teaching resources available at the present university and fashion-related educational institutions. This research could help us train technical human resources to be highly adaptable in industrial settings. The results of this study showed that the overall organization of contents is mostly divided into such categories as needlework kits, basic hand sewing, seam finishing, partial needlework and decorative needlework. The study results also indicated that such content organization must be considered in basic needlework/sewing processes and that each content needs to provide more various and detailed information by reflecting recent trends in design. Partial needlework has different applications in terms of interlining attachment, subsidiary materials, or sewing techniques; therefore, consistent descriptions and standard guidelines should be given according to what material is used and which design is planned. This study found that most teaching resources covered only needlework or sewing techniques without giving specific descriptions of types of materials, lining and interlining that can have great influence on sewing methods and instructions on how to use the materials. These findings suggest that the teaching resources need to add further technical instructions for the proper use of materials especially in response to the recent release of brand-new materials and sewing machines in the market.

The Influences of Additives and Curing Temperature on the Expansion Pressure of Calcium Oxide Hydration (생석회의 팽창압 발현에 미치는 첨가제 및 양생온도의 영향)

  • Kim, Won-Ki;Soh, Jeong-Soeb;Kim, Hoon-Sang;Kim, Hong-Joo;Lee, Won-Jun;Shin, Jin-Ho
    • Journal of the Korean Ceramic Society
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    • v.44 no.9
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    • pp.529-535
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    • 2007
  • Calcium oxide has been used as a demolition agent in fracturing rocks and old concrete structures, etc. With the agent, demolition work can be done in safety without a noise, vibration and any other pollution, since high expansive pressure is obtained gradually by only mixing the agents with water and pouring the slurry into boreholes. But application of the non-explosive demolition agent is a time-consuming job, especially in winter. Essentially, this problem is related to the reaction rate of calcium oxide with water. This study examines the influence of additives such as cement and anhydrite on expansion pressure of calcium oxide at different curing temperatures. The expansion pressure of calcium oxide began to increase steadily with the rise of the curing temperature. When mixing calcium oxide alone with water, blown-out shot occurred. But as additives were added to calcium oxide, the reaction of calcium oxide delayed and the expansion pressure showed gradual increment. Especially, anhydrite showed a superior delaying effect than cement on the reaction of calcium oxide.

Cross-sectional TEM Specimen Preparation of GaN-based Thinfilm Materials Using Alumina Dummy Filler (Alumina dummy 충전재를 이용한 GaN 기반 박막재료의 단면 TEM 시편준비)

  • Oh, Sang-Ho;Choi, Joo-Hyoung;Song, Kyung;Jeung, Jong-Man;Kim, Jin-Gyu;Yu, In-Keun;Yoo, Suk-Jae;Kim, Young-Min
    • Applied Microscopy
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    • v.39 no.3
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    • pp.277-281
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    • 2009
  • Practical difficulties for preparing a good crosssectional specimen of GaN-based materials for transmission electron microscopy have arisen due to large difference of mechanical properties between hard ceramic substrate and soft GaN-layered materials. Uneven polishing, sudden cracking, delamination, and selective sputtering during the conventional wedge polishing technique are often encountered as experimental hindrances. The preparation technique based on Strecker's method can be applied to overcome these difficulties, which eventually leads to mechanically stable TEM samples independent of the mechanical properties of materials. The basic idea is to use hard ceramic dummy filler for embedding the sample of interest into the dummy frame. In this study, we applied this technique into preparing cross-sectional TEM specimen of the GaN-based materials with mechanical instability and demonstrated usefulness of this hard dummy filler method in which the possible modifications of the sample of interest during the preparation must be avoidable. In addition, practical precautions during the preparation were discussed.

Electroluminescent Properties of Spiro[fluorene-benzofluorene]-Containing Blue Light Emitting Materials

  • Jeon, Soon-Ok;Lee, Hyun-Seok;Jeon, Young-Min;Kim, Joon-Woo;Lee, Chil-Won;Gong, Myoung-Seon
    • Bulletin of the Korean Chemical Society
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    • v.30 no.4
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    • pp.863-868
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    • 2009
  • New spiro[fluorene-7,9′-benzofluorene]-based blue host material, 5-phenyl-spiro[fluorene-7,9′-benzofluorene] (BH-1P), was successfully prepared by reacting 5-bromo-spiro[fluorene-7,9′-benzofluorene] (1) with phenyl boronic acid through the Suzuki reaction. 5-(N,N-Diphenyl)amino-spiro[fluorene-7,9′-benzofluorene] (BH-1DPA) and diphenyl-[4-(2-[1,1;4,1]terphenyl-4-yl-vinyl)-phenyl]amine (BD-1) were used as dopant materials. 2,5-Bis-(2',2"- bipyridin-6-yl)-1,1-diphenyl-3,4-diphenylsilacyclopentadiene (ET4) and Alq3 were used as electron transfer materials. Their UV absorption, photoluminescence and thermal properties were examined. The blue OLEDs with the configuration of ITO/DNTPD/$\alpha$-NPD/BH-1P:5% dopant/$Alq_3$ or ET4/LiF-Al prepared from the BH-1P host and BH-1DPA and BD-1 dopants showed a blue EL spectrum at 452 nm at 10 V and a luminance of 923.9 cd/$m^2$ with an efficiency of 1.27 lm/W at a current density of 72.57 mA/$cm^2$.

Precision Molding of Polymeric Multi-Channel Optical Interconnection Devices Considering the Coefficient of Thermal Expansion of the Materials

  • Ahn, Seung-Ho;Han, Sang-Pil;Choi, Choon-Gi;Jeong, Myung-Yung
    • ETRI Journal
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    • v.25 no.4
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    • pp.266-269
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    • 2003
  • Polymeric multi-channel optical interconnection devices that are usually fabricated by transfer molding are indispensable for parallel interconnection in high speed, high capacity optical communication systems. This paper proposes a design technique considering the thermal behavior of materials, such as shrinkage and expansion during the molding process, to satisfy geometrical requirements that have less than 1 ${\mu}m$ tolerance. We also designed molds considering the thermal effects of the materials and fabricated multi-channel optical fiber connectors that have less than 1 ${\mu}m$ tolerance.

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