• 제목/요약/키워드: Ni content

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Electrochemical Charge and Discharge Characteristics of Zr-Based Laves Phase Hydrogen Storage Alloys (Zr계 라-베상 수소저장합금의 전기화학적 충·방전특성)

  • Lee, Jae-Myoung;Kim, Chan-Jung;Kim, Dai-Ryong
    • Journal of Hydrogen and New Energy
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    • v.5 no.2
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    • pp.99-109
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    • 1994
  • To develop high capacity hydrogen storage alloys for secondary Ni/MH batteries, electrochemical charge/discharge characteristics of $Zr_{1-x}Ti_xMn_{1-y}V_yNi_{1-z}M_z$ (M=Al,Co,Fe) alloys were investigated, in which $0.2{\leq}x{\leq}0.6$, $0.2{\leq}y{\leq}0.8$, $0.2{\leq}z{\leq}0.4$. With increasing Ti content(x) and/or decreasing V content(y), lattice constants and maximum theoretical capacities of the alloys were decreased and equilibrium pressure of hydrogen absorption were increased. Electrochemical discharge capacities were increased with increasing Ti content(x). Especially, the alloys of x= 0.4~0.6 showed better charge/discharge efficiencies than those of x<0.4. Discharge capacities of $Zr_{0.4}Ti_{0.6}Mn_{0.4}V_{0.6}Ni_{0.8}Fe_{0.2}$, $Zr_{0.4}Ti_{0.6}Mn_{0.4}V_{0.6}Ni_{0.8}Al_{0.2}$ and $Zr_{0.5}Ti_{0.5}Mn_{0.4}V_{0.6}Ni_{0.6}Co_{0.4}$ were 385, 328 and 333mAh/g, respectively. These alloys were fully activated within five charge/discharge cycles and had a good charge and discharge rate capabilities and temperature characteristics.

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Synthesis of Ni-YSZ cermets for SOFC by glycine nitrate process (Glycine nitrate process에 의한 SOFC용 Ni-YSZ cermets 제조)

  • Lee, Tae-Suk;Ko, Jung-Hoon;Kim, Bok-Hee
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.20 no.6
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    • pp.289-294
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    • 2010
  • Ni-YSZ (Yttria Stabilized Zirconia) composite powders for SOFC were fabricated by glycine nitrate process. $ZrO(NO_3)_2{\cdot}2H_2O$, $Y(NO_3)_3{\cdot}6H_2O$, $Ni(NO_3)_2{\cdot}6H_2O$ and glycine were chosen as the starting materials. The structural properties of the sintered Ni-YSZ cermets have been investigated with respect to the volume contents of Ni. A porous microstructure consisting of homogeneously distributed Ni and YSZ phases together with well-connected grains was observed. The sintered Ni-YSZ cermets showed a porous microstructure consists of homogeneously distributed Ni and YSZ phases and the grains were well-connected. It was found that the open porosity is sensitive to the volume content of Ni. The Ni-YSZ cermet containing 35 vol% Ni seems to be suitable for the electrode material of SOFC since it provides sufficient open porosity higher than 30%.

Effect of Thermomechanical Treatment on the Phase Transformation and Superelasticity in Ti-Ni-Cu Shape Memory Alloy (Ti-Ni-Cu 형상기억합금의 상변태 및 초탄성에 미치는 가공열처리의 영향)

  • Lee, O.Y.;Park, Y.K.;Chun, B.S.
    • Journal of the Korean Society for Heat Treatment
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    • v.7 no.4
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    • pp.253-261
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    • 1994
  • Transformation behavior and superelastic behavior of Ti-Ni-Cu alloys with various Cu content has been investigated by means of electrical resistivity measurement, X-ray diffraction, tensile test and transmission electron microscopy. Two types of heat treatment are given to the specimens: i) Solutions treatment. ii) thermo-mechanical treatment. The transformation sequence in solution treated Ti-Ni-Cu Alloys substituted by Cu for Ni up to 5at.% occurs to $B2{\rightleftarrows}B19^{\prime}$ and it proceeds in two stages by addition of 10at.%Cu, i. e, $B2{\rightleftarrows}B19{\rightleftarrows}B19^{\prime}$. Also, it has been found that Ti-30Ni-20Cu alloy transformed in one stage : $B2{\rightleftarrows}B19$. The thermo-mechanically treated Ti-47Ni-3Cu alloy transformed in two stages: B2${\rightleftarrows}$rhomboheral phase${\rightleftarrows}B19^{\prime}$, while transformation sequence in Ti-45Ni-5Cu and Ti-40Ni-10Cu alloy transformed as same as solution treated specimens. The critical stress for inducing slip deformation in solution treated and thermo-mechanically treated Ti-40Ni-10Cu alloy is about 90MPa and 320Mpa respectively.

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Manufacture Properties of the Ultrafine NiO/YSZ Solid Oxide Composite (초미분체 NiO/YSZ 고체산화물 복합재료의 제조특성)

  • 최창주;김창석;오무송;김태성
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.07a
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    • pp.1080-1083
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    • 2001
  • Ultrafine NiO/YSZ composite powders were prepared by using a glycine nitrate process for anode material of solid oxide fuel cells. The specific surface areas of synthesized NiO/YSZ composite powders were examined with controlling pH of a precursor solution and the content of glycine. The characteristics of synthesized composite powders were examined with X-ray diffractometer, a BET method with N$_2$absorption, scanning and transmission electron microscopy. The strongly acid precursor solution increased the specific surface area of the synthesized composite powders. This is suggested to be caused by the increased binding of metal ions and glycine under a strong acid solution of pH=0.5 that lets glycine consist of mainly the amine group of NH$_3$$\^$+/. After sintering and reducing treatment of NiO/YSZ composite powders synthesized by GNP, the Ni/YSZ pellet showed ideal micro-structure very fine Ni parties of 3-5${\mu}$m were distributed uniformly and fine pores around Ni metal particles were formed, thes, leading to an increase of the triple phase boundary among gas Ni and YSZ.

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Microstructure and Magnetic Property of Nanostructured NiZn Ferrite Powder

  • Nam, Joong-Hee
    • Journal of the Korean Ceramic Society
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    • v.39 no.12
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    • pp.1119-1123
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    • 2002
  • Nanostructured spinel NiZn ferrites were prepared by the sol-gel method from metal nitrate raw materials. Analyses by X-ray diffraction and scanning electron microscopy showed the average particle size of NiZn ferrite was under 50 nm. The single phase of NiZn ferrites was obtained by firing at 250${\circ}C$, resulting in nanoparticles exhibiting normal ferrimagnetic behavior. The nanostructured $Ni_{1-X}Zn_XFe_2O_4$ (x=0.0∼1.0) were found to have the cubic spinel structure of which the lattice constants ${\alpha}_2$ increases linearly from 8.339 to 8.427 ${\AA}$ with increasing Zn content x, following Vegard's law, approximately. The saturation magnetization $M_s$ was 48 emu/g for x=0.4 and decreased to 8.0 emu/g for higher Zn contents suggesting the typical ferrimagnetism in mixed spinel ferrites. Pure NiZn ferrite phase substituted by Cu was observed before using the additive but hematite phase was partially appeared at $Ni_{0.2}Zn_{0.2}Cu_{0.6}Fe_2O_4$. On the other hand, the hematite phase in this NiZn Cu ferrite was disappeared after using the additive of acethyl aceton with small amount. The saturation magnetization Ms of $Ni_{0.2}Zn_{0.8-y}Cu_yFe_2O_4$(y=0.2∼0.6) as measured was about 51 emu/g at 77K and 19 emu/g at room temperature, respectively.

The Study of an Extended Cultural Dimensions Index based on the Content (콘텐츠 중심의 확장형 문화 차원 지수 연구)

  • Oh, Jung-Min;Moon, Nammee
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.9
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    • pp.77-84
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    • 2013
  • There are lots of tries to make a combination between the technology development which is fast arisen and cultural phenomenon which imply in it. We called this research area as the cultural computing or cultural modeling. In this paper, we examine the cultural user interface design, especially cultural design structure based on the contents considering the research trend of the cultural modeling. To design of the contents based on the culture, there is a need to draw a structure of the cultural feature for the contents. To do this, we combine Hofstede's cultural dimensions model with the data of contents and then we suggest cultural index of content(CiCo). Furthermore, we draw national index of cultural content(NiCC), through conjoining CiCo with preference pattern of content consumption for the nations. Suggested CiCo and NiCC are based on Hofstede's model, however they are improved approximately 10% of the explanatory of model than the Hofstede's.

Fabrication and Electrical Properties of Ni-Mn-Co-Fe Oxide Thick Film NTC Thermistors (Ni-Mn-Co-Fe 산화물 후막 NTC 서미스터의 제조 및 전기적 특성)

  • Park, Kyeong-Soon;Bang, Dae-Young;Yun, Sung-Jin;Choi, Byung-Hyun
    • Journal of the Korean Ceramic Society
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    • v.39 no.10
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    • pp.912-918
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    • 2002
  • Ni-Mn-Co-Fe oxide thick films were coated on an alumina substrate by screening printing technique. The microstructure and electrical properties of the thick films, as a function of composition and sintering temperature, were investigated. The components of the NTC thick films sintered at 1150${\circ}C$ were distributed homogeneously. On the other hand, in the case of the NTC thick films sintered at 1200 and 1250${\circ}C$, Co element was distributed homogeneously, but Ni, Mn and Fe elements were distributed heterogeneously, resulting in the formation of Ni rich and Mn-Fe rich regions. All the thick film NTC thermistors prepared showed a linear relationship between log resistance (log R) and the reciprocal of absolute temperature (1/T), indicative of NTC characteristics. At a given NiO and $Mn_3O_4$ content, the resistance, B constant and activation energy of $(Ni_{1.0}Mn_{1.0}Co_{1-x}Fe_x)O_4$ (0.25${\le}$x${\le}$0.75) and $(Ni_{0.75}Mn_{1.25}Co_{1-x}Fe_x)O_4$ (0.25${\le}$x${\le}$0.75) thermistors increased with increasing $Fe_2O_3$ content.

Electrical properties of polyethylene composite films filled with nickel powder and short carbon fiber hybrid filler

  • Mironov, V.S.;Kim, Seong Yun;Park, Min
    • Carbon letters
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    • v.14 no.2
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    • pp.105-109
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    • 2013
  • Effects of the amount of nickel powder (Ni) in Ni-carbon fiber (CF) hybrid filler systems on the conductivity(or resistivity) and thermal coefficient of resistance (TCR) of filled high density polyethylene were studied. Increases of the resistivity and TCR with increasing Ni concentration at a given hybrid filler content were observed. Using the fiber contact model, we showed that the main role of Ni in the hybrid filler system is to decrease the interfiber contact resistance when Ni concentration is less than the threshold point. The formation of structural defects leading to reduced reinforcing effect resulted in both a reduction of strength and an increase of the coefficient of thermal expansion in the composite film; these changes are responsible for the increases of both resistivity and TCR with increasing Ni concentration in the hybrid filler system.

Microstructure and Properties of Nano-Sized Ni-Fe Alloy Dispersed Al2O3 Composites (Ni-Fe 합금입자 분산 Al2O3 나노복합재료의 미세조직 및 특성)

  • 남궁석;정재영;오승탁;이재성;이홍재;정영근
    • Journal of Powder Materials
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    • v.9 no.3
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    • pp.161-166
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    • 2002
  • Processing and properties of $Al_2O_3$ composites with Ni-Fe content of 10 and 15 wt% were investigated. Homogeneous powder mixtures of $Al_2O_3$/Ni-Fe alloy were prepared by the solution-chemistry route using $Al_2O_3$, $Ni(NO_3)_2{\cdot}6H_2O$ and $Fe(NO_3)_3{\cdot}9H_2O$ powders. Microstructural observation of composite powder revealed that Ni-Fe alloy particles with a size of 20nm were homogeneously dispersed on $Al_2O_3$ powder surfaces. Hot-pressed composites showed enhanced fracture toughness and magnetic response. The properties are discussed based on the observed microstructural characteristics.

Nanocomposite Ni-CGO Synthesized by the Citric Method as a Substrate for Thin-film IT-SOFC

  • Wang, Zhenwei;Liu, Yu;Hashimoto, Shin-ichi;Mori, Masashi
    • Journal of the Korean Ceramic Society
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    • v.45 no.12
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    • pp.782-787
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    • 2008
  • Ni-ceria cermets have been extensively investigated as candidates for the anode in intermediate-temperature solid oxide fuel cells. We have used the citric method to synthesize nanocomposite powders consisting of NiO (Ni metal content: $40{\sim}60%$ by volume) highly dispersed in $Ce_{0.9}Gd_{0.1}O_{1.95}$ (CGO). The microstructure characteristics and sintering behaviors of the nanocomposites were investigated. No impurity phases were observed and the shrinkage of these substrates matched well with that of a CGO electrolyte with a specific surface area of $11\;m^2/g$. Densification of the CGO electrolyte layer to $<5\;{\mu}m$ thickness was achieved by co-firing the laminated electrolyte with the porous NiO-CGO substrate at $1400^{\circ}C$ for 6 h.