• Title/Summary/Keyword: Grain-oriented

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Characteristics of Grain Orientation and Grain Boundaries of the $ZrB_2$-ZrC Composites Densified by Spark Plasma Sintering (방전플라즈마소결법으로 제조된 $ZrB_2$-ZrC 복합체의 결정립 방위분포 및 결정입계의 특성)

  • Shim, Seung-Hwan;Kim, Kyoung-Hun;Shim, Kwang-Bo
    • Journal of the Korean Ceramic Society
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    • v.38 no.10
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    • pp.914-920
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    • 2001
  • The grain orientation distribution and grain boundary characterization of $ZrB_2$-ZrC composites sintered by a SPS(Spark Plasma Sintering) method, a new sintering technique were analyzed by the EBSP technique and then their crystallographic results have been compared with those of a sintered specimen using a PLS(Pressureless Sintering) method. In the $ZrB_2$-ZrC composite manufactured by SPS, (0001) planes of $ZrB_2$ were oriented in the direction normal to the specimen surface. In the case of PLS, those of $ZrB_2$ were oriented normal to the electron beam. In both cases of PLS and SPS, ZrC grains had the randomly oriented grain structure. The grain boundary characterization showed that low angle grain boundaries in the PLS and SPS processed materials constituted about 10% and 8% of the total number of boundaries, respectively, represented the only slight difference between the proportion of low angle grain boundary. However, in the distribution of CSL(Coincident Site Lattice) boundaries, it was shown the higher proportion of CSL boundaries with $\Sigma$ 3,5,7,9, 11 in the SPS processed material.

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Low Temperature Processing of $SrBi_2Ta_2O_9$ Thin Films

  • Choelhwyi Bae;Lee, Jeon-Kook;Park, Dongkyun;Jung, Hyung-Jin
    • The Korean Journal of Ceramics
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    • v.6 no.2
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    • pp.110-115
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    • 2000
  • $SrBi_2Ta_2O_9$ thin films were deposited at room temperature on the usual (111) oriented Pt bottom electrodes using r.f. magnetron sputtering, and then post-annealed at 650-$800^{\circ}C$ for 30min in oxygen flow. Low temperature processing which shows the preferred oriented SBT thin films was obtained by controlling the sputtering pressure and/or Sr content in target. The orientation and grain growth behavior of SBT thin films were dependent on Sr contents in films. With increasing the excess Bi content up to 50% in SBT thin films, it was possible to lower the onset temperature of grain growth. The c-axis preferred oriented SBT thin films were well-grown under the condition of low post-annealing($650^{\circ}C$) by lowering post-annealing pressure. After $10^{11}$ switching cycles, no polarization degradation was observed in both preferred oriented SBT capacitors.

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Growth of super-grain pentacene by OVPD for AMLCD

  • Jung, Ji-Sim;Cho, Kyu-Sik;Jang, Jin
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.163-166
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    • 2002
  • We studied the growth of large-grain pentacene film by organic vapour phase deposition. The optimizations of the growth of pentacene are carried out by varying the gas pressure in the reactor and substrate temperature. We found that the grain size depends strongly on the gas pressure in the reactor. The grain size of $20{\mu}m$ has been obtained at the gas pressure of 200 Torr. The film was found to be strongly (001) oriented and its grain size decreases with decreasing the gas pressure.

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Effect of Primary Recrystallization Texture on the Formation of Grain Growth Texture in Aluminum 1050 Sheet (알루미늄 1050계 판재에서 결정립 성장 집합조직에 미치는 재결정 집합조직의 영향)

  • Kim, Hyun-Chul;Kang, Hyung-Gu;Huh, Moo-Young
    • Korean Journal of Metals and Materials
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    • v.47 no.6
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    • pp.356-362
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    • 2009
  • In order to vary the primary recrystallization textures, AA 1050 sheets were cold rolled in two different manners. Differences in cold rolling schedule gave rise to the formation of different cold rolling textures also leading to the formation of different primary recrystallization textures. Upon annealing for grain growth, changes in microstructure and texture hardly occurred in the sample depicting Cube recrystallization texture, while grain growth was accompanied with the development {001}<100> Cube texture in the sample displaying a recrystallization texture comprising of weak rolling texture components. The selective growth of Cube oriented grains is attributed to the high mobility of their grain boundaries.

A Computationally Efficient Finite Element Analysis Algorithm Considering 2-D Magnetic Properties of Electrical Steel Sheet

  • Yao, Yingying;Li, Wei;Yoon, Hee-Sung;Fujiwara, Koji;Koh, Chang-Seop
    • Journal of Electrical Engineering and Technology
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    • v.3 no.3
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    • pp.385-390
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    • 2008
  • For taking account of the two-dimensional magnetic properties of a grain-oriented electrical steel sheet, the effective anisotropic tensor reluctivity is examined, and a computationally efficient algorithm is suggested by using the response surface method to model the two-dimensional magnetic properties. It is shown that the reconstructed two-dimensional magnetic properties are fairly effective to stabilize the convergence characteristics of the Newton-Raphson iteration in the nonlinear magnetic field analysis.

Comparison of iron loss characteristics between thin-gauged grain-oriented 3% Si-Fe sheets and commercial 0.3 mm-thick grain-oriented electrical sheets (극박 방향성 규소강판과 상용 방향성 규소강판의 철손특성 비교)

  • Cho, Seong-Soo;Kim, Sang-Beom;Soh, Joon-Young;Chae, U-Gyu;Han, Sang-Ok
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.2009_2010
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    • 2009
  • Thin-gauged 3% Si-Fe sheets having a high magnetic induction of over 1.9 T have been developed for the purpose of applications where operation frequency is higher than power frequency. In order to clarify requirements of iron loss characteristics for the applications, iron loss characteristics of the newly developed strip were investigated by iron loss separation method and were compared with those of commercially produced 0.3 mm-thick electrical sheets. In case of relatively high excitation induction(1.7 T) and low frequency(60 Hz), reducing hysteresis loss is effective to decrease total iron loss. In case of relatively low excitation induction(1.0 T) and high frequency(1 kHz), reducing eddy-current loss is effective by decreasing thickness and grain size to improve total iron loss.

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Relations of Whole Grain Consumption with Predisposing, Reinforcing, and Enabling Factors among Korean Adults (일부 한국 성인의 전곡류 섭취빈도와 동기부여, 행동강화, 행동가능 요인간의 연관성)

  • Chae, Da-Hae;Yum, Jin-Hee;Lee, Seung Min
    • Journal of the Korean Dietetic Association
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    • v.20 no.2
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    • pp.133-148
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    • 2014
  • This study compared levels of whole grain consumption-related predisposing, reinforcing, and enabling factors according to socio-demographic variables, and examined how these factors are associated with whole grain consumption frequency among Korean adults. A survey questionnaire was administered to a convenience sample of adult males and females aged 20~59 years (n=300). The questionnaire included questions on predisposing, reinforcing, and enabling factors in relation to whole grain consumption as well as a brief whole grain food frequency questionnaire. Female subjects showed a significantly higher level of negative beliefs on health nutrition taste texture while showing a significantly lower level of social support compared to that of males. The age group of 40~59 years showed a significantly higher social support level than the age group of 20~39 years. Results from multivariate regression analyses showed that different combinations of predisposing, reinforcing, and enabling variables were significant in predicting whole grain consumption frequency according to sex and age. The study findings can be used for developing specific target-oriented nutrition intervention programs for promotion of whole grain intake among Korean adults.