• Title/Summary/Keyword: Phase screen

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국가연구개발사업 중간평가방법 연구-선도기술개발사업에의 적용사례-

  • 임윤철;이철원
    • Journal of Technology Innovation
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    • v.5 no.2
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    • pp.126-154
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    • 1997
  • This paper addresses a methodology for monitoring the first phase('92-94') progress and its implication fo Highly Advanced National R&D Projects (HAN or G7 project) in Korea. The authors suggest a three-stage life cycle model for the management of national R&D program; planning stage, implementing & monitoring stage, and evaluating & harvesting stage. The interim evaluation, the main focuses of this paper, is one of the key issues for the effective management of national R&D program at the implementing & monitoring stage. The conceptual framework of the interim evaluation was developed both through reviewing related literature and considering the characteristics of the HAN program. A stepwise procedure of interim evaluation was introduced: 'initial screen' and 'detailed examination'. At initial screen all 11 projects were reviewed in terms of both their relevance and performance in order to decide whether further detailed scrutiny is needed or not. If there exist critical problems on the relevance or on the intermediate progress of each project, it is to be under further detailed examination. Evaluation was initiated by the G7 Planning and Evaluation Committee, which was established for advising, directing, and monitoring the HAN Projects, with the help of large number of experts from industries, universities, and research institutes. The monitoring results were reported to the related ministries and project coordinating agencies, and reflected in the second phase.

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Fabrication of $Bi_{2}Sr_{2}CaCu_{2}O_{8}$ Superconducting Films by the LiReac-PreCu Method (급속반응공정에 의한 동 테이프 $Bi_{2}Sr_{2}CaCu_{2}O_{8}$)

  • 성현태;한상철;한영희;이준성;최희락
    • Progress in Superconductivity and Cryogenics
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    • v.1 no.1
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    • pp.7-14
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    • 1999
  • Wekk oriented $Bi_{2} Sr_{2} CaCu_{2} O_{8}$ suppercondcting thick films were fabricared on copper tape by LiReac-PreCu (liquid reaction between a Cu-free precousor and Cu tape) method. Cu-free precursor power which is composed of $Bi_{2}Sr_{2}Ca_{5}$ was printed on a copper tape by screen printing and was heat-treated. The speciment were partially in a molten state at the heat treatment temperature (85$0^{\circ}C$~87$0^{\circ}C$). The heat heat treatments for the reaction were performed in air or low oxygen pressure in several stages. XRD analyses of the resulting Bi2Sr2CaCu2O8 superconducting tapes show that the $Bi_{2} Sr_{2} CaCu_{2} O_{8}$ phase is dominant and a small amount of $Bi_{2} Sr_{2} Cu_{2} O_{6}$ phase is detected. Both phases are aligned in the c-axis direction.

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Fabrication and Sensing Properties of NASICON Thick Film SO2 Gas Sensor Using Screen-print Method (스크린 인쇄법을 이용한 NASICON 후막 SO2가스 센서의 제조 및 특성)

  • Bae, J.C.;Lee, S.T.;Jun, H.K.;Bang, Y.I.;Lee, D.D.;Huh, J.S.
    • Korean Journal of Materials Research
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    • v.13 no.2
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    • pp.115-119
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    • 2003
  • The thick film type sensor having Pt/Na Super Ionic Conductor(NASICON) solid electrolyte/Pt/$Na_2$$SO_4$/Pt catalyst system for $SO_2$gas was fabricated by screen-print method. The phase of Na Super Ionic Conductor solid electrolyte sintered at different temperature of 1050, 1150,$ 1250^{\circ}C$ and for different time of 1.5, 2.5, 3.5 hr were investigated by XRD. The Electromotive Force variation of the sensor with $SO_2$concentrations and operating temperatures were investigated. The major phase of Na Super Ionic Conductor film sintered at 115$0^{\circ}C$ for 3.5 hr was sodium zirconium silicon phosphate($Na_3$Zr$_2$$Si_2$PO$_{12}$). The Nernst's slope of Na Super Ionic Conductor sensor for $SO_2$gas with the variation of concentration from 10 to 100 ppm was 167.14 ㎷/decade at the operating temperature of $500 ^{\circ}C$. The increase of oxygen partial pressure was not affected to the variation of Nernst's slope.e.

Influence of Yb2O3 Doping Amount on Screen-printed Barium Strontium Calcium Titanate Thick Films

  • Noh, Hyun-Ji;Lee, Sung-Gap;Ahn, Byeong-Lib;Lee, Ju
    • Transactions on Electrical and Electronic Materials
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    • v.8 no.6
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    • pp.241-245
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    • 2007
  • [ $(Ba_{0.9-x}Sr_xCa_{0.10})TiO_3$ ] (x=0.33, 0.36) powders were prepared by sol-gel method. $(Ba,Sr,Ca)TiO_3$(BSCT) thick films, undoped and doped with $MnCO_3$ and $Yb_2O_3(0.1{\sim}0.7mol%)$, were fabricated by the screen printing method on the alumina substrate. The coating and drying procedure was repeated 6-times. The Pt bottom electrode was screen printing method on the alumina substrate. These BSCT thick films were annealed at $1420^{\circ}C$ for 2 hr in atmosphere. The upper electrodes were fabricated by screen printing the Ag paste and then firing at $590^{\circ}C$ for 10 min. And then the structured and dielectric properties as a function of the doping amount of $Yb_2O_3$ were studied. As a result of the TG-DTA, exothermic peak was observed at around $670^{\circ}C$ due to the formation of the polycrystalline perovskite phase. All BSCT thick films showed XRD patterns of typical cubic peroveskite structure. The average thickness of BSCT thick films was about $70^{\mu}m$. The curie temperature and the dielectric constant decreased with increasing $Yb_2O_3$ doped content and the relative dielectric constant of the specimen, doped with 0.5 mol% $Yb_2O_3$ at BSCT(54/36/10), showed a best value of 5018 at curie temperature.

Fabrication of Cu-Sheathed Bi-Sr-Cu-O High Temperature Superconductor Thick Films (동피복재법을 이용한 Bi-Sr-Ca-Cu-O 고온초전도 후막 제조)

  • 한상철;성태현;한영희;이준성;정상진
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 1999.02a
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    • pp.22-25
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    • 1999
  • A well oriented Bi-2212 superconductor thick films were fabricated by screen printing with a Cu-free Bi-Sr-Ca-Cu-O powder on a copper plate and heat-treating at 820- $880^{\circ}C$for several minute in low oxygen pressure or are. At minute in low oxygen pressure of air. At , the printing layer partially melted by reaction between the Cu-free precursor by reaction between the Cu-free$870^{\circ}C$ precursor and CuO of the oxidizing copper plate. It is believed that the solid phase is Bi : Sr : Ca : Cu = 2 : 2 : 0 : 1. It is likely that the Bi-2212 superconducting phase is formed at Bi-2212 superconducting phase is formed at Bi-free phase/liquid interface by nucleation and grows.

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Phase Identification of Al-Ti Alloys Using Convergent Beam Electron Diffraction Pattern (수렴성 빔 전자회절 도형을 이용한 Al-Ti 합금의 상 분석)

  • Kim, Hye-Sung
    • Journal of the Korean Society of Industry Convergence
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    • v.4 no.2
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    • pp.149-155
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    • 2001
  • The use of primitive cell volume and zero order Laue (ZOLZ) pattern is proposed to identify phase in a complex microstructure. Single convergent beam electron pattern containing higher order Laue zone ring from a nanosized region is sufficient to calculate the primitive cell volume of the phase, while ZOLZ pattern is used to determine the zone axis of the crystal. A computer program is used to screen out possible phases from the value of measured cell volume from convergent beam electron diffraction (CBED) pattern. Indexing of ZOLZ pattern follows in the program to find the zone axis of the identification from a single CBED pattern. An example of the analysis is given from the rapidly solidified $Al-Al_3Ti$ system.

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Evaluation of Chest Density in Insight Film (Insight film을 이용한 농도측정 평가)

  • Kwon, Lee-Seon;Park, Jang-Hwan;Lim, Oh-Soo;Jung, Kyong-Mo;Cheung, Hwan
    • Journal of radiological science and technology
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    • v.15 no.2
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    • pp.17-23
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    • 1992
  • Simple chest radiography is the most frequently performed examination in radiologic practice. However, with transmitted dose through chest which has the problem of wide variations in absorption, conventional Film/Screen Combinations Method make it difficult to delineate lung field mediastinum & cardia portion and subdiaphragmatic structures. In order to overcome this problem, we have been tried several methods as follows. High Kilovoltage Technique, Rare Earth Screen/Wide Lattitude Film, Use of Compensating Filter and Digital Beam Attenuator and recently Insigh System has been developed. In this paper, we'd like to discuss Insight film through apperciation by measuring the difference of contrast. In order to evaluate insight film. We have done experiments using Insight System with Simple Phase, Picker 550. We could get an result which was able to overcome the limitted dynamic range of conventional Film/Screen System remarkably.

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Dielectric and Pyroelectric Properties of Dy-doped BSCT Thick Films by Screen-printing Method

  • Noh, Hyun-Ji;Lee, Sung-Gap;Nam, Sung-Pill
    • Journal of Electrical Engineering and Technology
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    • v.4 no.4
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    • pp.527-530
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    • 2009
  • $(Ba_{0.57}Sr_{0.33}Ca_{0.10})TiO_3$(=BSCT) powders, prepared by the sol-gel method, were doped using $MnCO_3$ as the acceptor and $Dy_2O_3$ as the donor. This powder was mixed with an organic vehicle. BSCT thick films were fabricated by the screen-printing techniques on the alumina substrate. The structural and dielectric properties of BSCT thick films were investigated with variation of the $Dy_2O_3$ amount. As a result of the differential thermal analysis (DTA), the exothermic peak was observed at around $670^{\circ}C$ due to the formation of the polycrystalline perovskite phase. All the BSCT thick films showed the XRD patterns of a typical polycrystalline perovskite structure. The average grain size of BSCT thick films decreased with an increasing amount of $Dy_2O_3$. The relative dielectric constant and dielectric loss of the BSCT thick film doped $Dy_2O_3$ 0.1mol% were 4637.4 and 1.6% at 1kHz, respectively.

Preparation of pyroelectric BSCT thick films by screen-printing (스크린 프린팅을 이용한 초전형 BSCT 후막의 제작)

  • Noh, Hyun-Ji;Lee, Sung-Gap;Nam, Sung-Pill;Lee, Young-Hie
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.165-166
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    • 2008
  • $(Ba_{0.6},Sr_{0.3},Ca_{0.1})TiO_3$ powders, which were prepared by sol-gel method using a solution of Ba-acetate, Sr-acetate and Ca-acetate and Ti iso-propoxide, were mixed with organic vehicle and the BSCT thick films were fabricated by the screen-printing techniques on high purity alumina substrates. The structural and dielectirc properties were investigated for various $Pr_2O_3$ and $Y_2O_3$doping contents. As a result of thermal analysis of $(Ba_{0.6},Sr_{0.3},Ca_{0.1})TiO_3$ powders, the exothermic peak was observed at around $670^{\circ}C$ due to the formation of the polycrystalline perovskite phase. All BSCT thick films, sintered at $1420^{\circ}C$ for 2h, showed the typical XRD patterns of perovskite polycrystalline structure. The average grain size of the specimens decreased with amount of $Pr_2O_3$ and $Y_2O_3$ contents.

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