• 제목/요약/키워드: BeO

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THE ANALOGUE OF WIENER SPACE WITH VALUES IN ORLICZ SPACE

  • Ryu, Kun Sik
    • 충청수학회지
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    • 제27권4호
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    • pp.689-695
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    • 2014
  • Let M be an N-function satisfies the ${\Delta}_2$-condition and let $O_M$ be the Orlicz space associated with M. Let $C(O_M)$ be the space of all continuous functions defined on the interval [0, T] with values in $O_M$. In this note, we define the analogue of Wiener measure $m^M_{\phi}$ on $C(O_M)$, establish the Wiener integration formulae for the cylinder functions on $C(O_M)$ and give some examples related to our formulae.

Effect of the supporting substrate on the production yield for geometrically controlled carbon coils

  • Park, Se-Mi;Kim, Sung-Hoon;Jeon, Young-Chul;Kim, DongUk
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2012년도 춘계학술발표회 논문집
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    • pp.218-219
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    • 2012
  • Carbon coils could be synthesized using $C_2H_2/H_2$ as source gases and $SF_6$ as an incorporated additive gas under thermal chemical vapor deposition system. Prior to the carbon coils deposition reaction, two kinds of samples having different combination of Ni catalyst and substrate were employed, namely a commercially-made $Al_2O_3$ ceramic boat with Ni powders and a commercially-made $Al_2O_3$ substrate with Ni layer. By using a commercially-made $Al_2O_3$ ceramic boat, the production yield of carbon coils could be enhanced as much as 10 times higher than that of $Al_2O_3$ substrate. Furthermore, the dominant formation of the microsized carbon coils could be obtained by using $Al_2O_3$ ceramic boat.

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비선형성 ZnO 바리스터의 Prebreakdown 영역에서의 전도 현상 (Conduction Mechanism of Non-linearity ZnO Varistor in the Prebreakdown region)

  • 한세원;강형부
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1995년도 추계학술대회 논문집
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    • pp.74-76
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    • 1995
  • ZnO varistor with composition of ZnO(90wt%)-Bi$_2$O$_3$(3wt%)-Sb$_2$O$_3$(3.6wt%)-CO$_2$O$_3$(1.16wt%)-NiO(0.88wt%)-MnO$_2$(0.71wt%)-Cr$_2$O$_3$(0.93wt%) according to Al$_2$O$_3$addtive was fabricated by sintering methods. The effects of Al$_2$O$_3$dopant on the I-V characteristics of ZnO varistors were investigated. These changes of electric properties were found to be caused by the variation of grains and grain boundary related to Al$_2$O$_3$dopting. And the conductive mechanism of ZnO varistor in prebreakdown region were investigated with defect model.

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Combinatorial Synthesis and Screening of the Tb-activated Phosphors in the System $CaO-Y_{2}O_3-Al_{2}O_{3}$

  • Yoon, Ho-Shin;Kim, Chang-Hae;Park, Hee-Dong;Ryu, Seung-Kon
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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    • pp.836-839
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    • 2003
  • We have synthesized some phosphors in the system $CaO-Y_{2}O_3-Al_{2}O_{3}$ by combinatorial polymerized-complex method. Composition and synthetic temperature of phosphors in the liblary was screened from the emission intensities of individual samples under VUV excitation. In $Tb^{3+}$-activated $CaO-Y_{2}O_3-Al_{2}O_{3}$, green phosphors showing good intensity were found to be $CaYAl_{3}O_{7}$, $CaYalO_{4}$, $YAlO_{3}$, $Y_{3}Al_{5}O_{12}$, $Y_{4}Al_{2}O_{9}$, $Ca_{3}Al_{2}O6$.

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공침법으로 제조한 $Al_2O_3-ZrO_2$ 계의 세라믹스의 기계적 성질 (Mechanical Properties of $Al_2O_3-ZrO_2$ Ceramics Prepared by Co-precipitation Method)

  • 이홍림;홍기곤;정형진
    • 한국세라믹학회지
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    • 제23권3호
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    • pp.44-52
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    • 1986
  • $Al_2O_3-ZrO_2$ ceramics was obtained by the co-precipitation method using $Al_2(SO_4)_2$.$18H_2O$ and $ZrOCl_2$.$8H_2O$ as starting materials $MgCl_2$.$6H_2O$ as a sintering aid and NH4OH as a hydrolyzing agent. The coprecipitate from the above raw materials was calcined at 125$0^{\circ}C$ for 1h and again sintered at 1$650^{\circ}C$ for 2h before measurements of strength hardness and fracture toughness. MgO addition was found to increase mechanical properties of the $Al_2O_3-ZrO_2$ system. The strength and frac-ture toughness of $Al_2O_3-ZrO_2$ ceramics were considered to be increased by stress-induced phase tranforma-tion of $ZrO_2$.

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PbO-B$_2$O$_3$-TiO$_2$-BaO계의 유리화에 대한 전이온도 및 성분 원소비의 영향 (Effects of Transition Temperature and Atomic Ratio on Glass Formation Tendency in the PbO-B$_2$O$_3$-TiO$_2$-BaO System)

  • 이선우;심광보;오근호
    • 한국세라믹학회지
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    • 제35권12호
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    • pp.1274-1279
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    • 1998
  • The glass forming ability of the PbO-B2O3-TiO3-BaO system was investigated in relation to transitieon tem-peratures and the atomic ratio between constituents. Glass forming tendency was improved as the tem-peratures and the atomic ratio between constituents. Glass forming tendency was improved as the tem-perature differences between liquidus temperature and crystallization(or glass transition) temperature de-creased and the temperature difference between crystallization and glass transition temperature increases. The atomic ratio could be used as a criterion to deign glass systems. The interposition of B and Ba atoms between Pb and Ti atoms was one of important factors in glass formation.

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ZnO, SnO2, ZTO 산화물반도체의 전기적인 특성 분석 (Analysis of Electrical Characteristics of Oxide Semiconductor of ZnO, SnO2 and ZTO)

  • 오데레사
    • 한국재료학회지
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    • 제25권7호
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    • pp.347-351
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    • 2015
  • To study the characteristics of ZTO, which is made using a target mixed $ZnO:SnO_2=1:1$, the ZnO and $SnO_2$ were analyzed using PL, XRD patterns, and electrical properties. Resulting characteristics were compared with the electrical characteristics of ZnO, $SnO_2$, and ZTO. The electrical characteristics of ZTO were found to improve with increasing of the annealing temperature due to the high degree of crystal structures at high temperature. The crystal structure of $SnO_2$ was also found to increase with increasing temperatures. So, the structure of ZTO was found to be affected by the annealing temperature and the molecules of $SnO_2$; the optical property of ZTO was similar to that of ZnO. Among the ZTO films, ZTO annealed at the highest temperature showed the highest capacitance and Schottky contact.

Support Effects of Containing Catalysts on Methanol Dehydrogenation

  • Jung, Kwang-Deog;Joo, Oh-Shim
    • Bulletin of the Korean Chemical Society
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    • 제23권8호
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    • pp.1135-1138
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    • 2002
  • CuO/ZnO, CuO/SiO,sub>2, and CuO/ZrO2 catalysts were prepared for investigating the support effects on methanol dehydrogenation. It was found that the conversion of methanol was proportional to the copper surface area on Cu/ZnO cat alysts and was independent on that on Cu/ZrO2 and Cu/SiO2. The highest copper surface area was obtained with the Cu/ZrO2 (9/1). The unusual deactivation of the Cu/ZnO, which showed the highest selectivity among the catalysts tested, was observed. Pulse reaction with methanol indicated that the lattice oxygen in ZnO could be removed by forming CO2 in the catalytic reaction, supporting that the ZnO reduction was responsible for the severe deactivation of the Cu/ZnO.

Characterization of ZnO/TiO2 Nanocomposites Prepared via the Sol-Gel Method

  • Hellen, Nalumaga;Park, Hyun;Kim, Kyung-Nam
    • 한국세라믹학회지
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    • 제55권2호
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    • pp.140-144
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    • 2018
  • $ZnO/TiO_2$ nanocomposites were synthesized via a modified sol-gel technique by incorporating 30 and 70 wt% $TiO_2$ nanopowder into a ZnO sol-gel matrix. Zinc acetate dihydrate was used as the ZnO precursor and de-ionized water as the solvent, while titanium oxysulfate was employed for the synthesis of $TiO_2$ nanopowder. The synthesized $ZnO/TiO_2$ nanocomposites were characterized by x-ray diffraction, UV-vis spectroscopy, scanning electron microscopy, and transmission electron microscopy. The $ZnO/TiO_2$ nanocomposites showed both the ZnO (wurtzite) and $TiO_2$ (anatase) phases. The average ZnO crystallite size of the $ZnO/TiO_2$ nanocomposites was found to be about 26.3 nm. The TEM results confirmed that spherical $TiO_2$ particles were embedded in the ZnO matrix. $TiO_2$ particles attached onto the rod-like ZnO particles were also observed. The $ZnO/TiO_2$ nanocomposites exhibited optical absorption properties superior to those of pure ZnO and $TiO_2$.

Effect of SiO2/B2O3 ratio on Li ion conductivity of a Li2O-B2O3-SiO2 glass electrolyte

  • Kim, Young Han;Yoon, Mi Young;Lee, Eun Jung;Hwang, Hae Jin
    • Journal of Ceramic Processing Research
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    • 제13권spc1호
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    • pp.37-41
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    • 2012
  • A lithium ion conducting borosilicate glass was fabricated by a conventional melt quenching technique from a mixture of Li2CO3, B2O3 and SiO2 powders. The Li ion conductivity of the lithium borosilicate glasses was evaluated in terms of the SiO2/B2O3 ratio. In the Li2O-B2O3-SiO2 ternary glass, the glass forming region decreases with an increasing Li2O content. At the same Li2O, the crystallization tendency of the glass samples increases with the SiO2/B2O3 ratio, resulting in a reduced glass forming region in the Li2O-B2O3-SiO2 ternary glass. The electrical conductivity moderately depends on the SiO2/B2O3 ratio in the Li2O-B2O3-SiO2 ternary glass. The conductivity of the glasses slightly increases with the SiO2/B2O3 ratio. The observed phenomenon can be explained by the modification of the glass structure as a function of the SiO2 content.