• Title/Summary/Keyword: ThO_{2}$

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Influences of Doping Methods on Microstructure and Fracture Toughness of Mo-La Alloys

  • Wang, Lin;Sun, Yuanjun;Luo, Jianhai;Zhu, Yongan;Niu, Pingwen
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.1327-1328
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    • 2006
  • Lanthanum oxide was introduced to molybdenum powder by liquid-liquid doping and liquid-solid doping respectively. Mo alloys were prepared by powder metallurgy technology. The size distribution and feature of dopant particles and the fractographs of Mo alloys were investigated by TEM and SEM respectively. The results indicated that liquid-liquid doping method is favorable for refining and dispersing $La_2O_3$ particles uniformly in matrix. Fracture toughness of Mo alloys prepared by liquid-liquid doping showed better results than that of liquid-solid doping. Furthermore, the influences of the size distribution of $La_2O_3$ on properties of Mo alloys was discussed by dislocation pile-up theory.

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Threshold Voltage control of Pentacene Thin-Film Transistor with Dual-Gate Structure

  • Koo, Jae-Bon;Ku, Chan-Hoe;Lim, Sang-Chul;Lee, Jung-Hun;Kim, Seong-Hyun;Lim, Jung-Wook;Yun, Sun-Jin;Yang, Yong-Suk;Suh, Kyung-Soo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.1103-1106
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    • 2006
  • We have presented a comprehensive study on threshold voltage $(V_{th})$ control of organic thin-film transistors (OTFTs) with dual-gate structure. The fabrication of dual-gate pentacene OTFTs using plasma-enhanced atomic layer deposited (PEALD) 150 nm thick $Al_2O_3$ as a bottom gate dielectric and 300 nm thick parylene or PEALD 200 nm thick $Al_2O_3$ as both a top gate dielectric and a passivation layer is reported. The $V_{th}$ of OTFT with 300 nm thick parylene as a top gate dielectric is changed from 4.7 V to 1.3 V and that with PEALD 200 nm thick $Al_2O_3$ as a top gate dielectric is changed from 1.95 V to -9.8 V when the voltage bias of top gate electrode is changed from -10 V to 10 V. The change of $V_{th}$ of OTFT with dual-gate structure has been successfully understood by an analysis of electrostatic potential.

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Threshold Voltage Control of Pentacene Thin-Film Transistor with Dual-Gate Structure

  • Koo, Jae-Bon;Ku, Chan-Hoe;Lim, Sang-Chul;Lee, Jung-Hun;Kim, Seong-Hyun;Lim, Jung-Wook;Yun, Sun-Jin;Yang, Yong-Suk;Suh, Kyung-Soo
    • Journal of Information Display
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    • v.7 no.3
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    • pp.27-30
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    • 2006
  • This paper presents a comprehensive study on threshold voltage $(V_{th})$ control of organic thin-film transistors (OTFTs) with dual-gate structure. The fabrication of dual-gate pentacene OTFTs using plasma-enhanced atomic layer deposited (PEALD) 150 nm thick $Al_{2}O_{3}$ as a bottom gate dielectric and 300 nm thick parylene or PEALD 200 nm thick $Al_{2}O_{3}$ as both a top gate dielectric and a passivation layer was investigated. The $V_{th}$ of OTFT with 300 nm thick parylene as a top gate dielectric was changed from 4.7 V to 1.3 V and that with PEALD 200 nm thick $Al_{2}O_{3}$ as a top gate dielectric was changed from 1.95 V to -9.8 V when the voltage bias of top gate electrode was changed from -10 V to 10 V. The change of $V_{th}$ of OTFT with dual-gate structure was successfully investigated by an analysis of electrostatic potential.

A Study on Properties of PVA/$SiO_2$ Organic-inorganic Hybrid Materials Barrier Layer Coated on Flexible Substrate (PEN)

  • Koo, Tae-Wook;Farva, Umme;Yu, Eric S.H.;Kim, Yun-Su;Park, Chin-Ho
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.657-659
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    • 2008
  • Barrier coating properties of PVA/$SiO_2$ on the flexible substrates (PEN) have been investigated. Thin layer of PVA/$SiO_2$ organic-inorganic hybrid materials were deposited on PEN substrate by the spin-coating. The optical properties and surface roughness of barrier layer on flexible substrate were characterized by AFM, UV-Vis and WVTR/ OTR.

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The Geochemistry of Yuksipryeong Two-Mica Leucogranite, Yeongnam Massif, Korea (영남육괴내 육십령 복운모화강암에 대한 지화학적 연구)

  • Koh, Jeong-Seon;Yun, Sung-Hyo
    • The Journal of the Petrological Society of Korea
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    • v.12 no.3
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    • pp.119-134
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    • 2003
  • Yuksipryeong two-mica granite presents strongly peraluminous characteristics in both mineralogy and geochemistry. It has high aluminum saturation index with 1.15∼l.20 and high corundum with 2.20∼2.98 wt% CIPW norm. As the color index is <16% and FeO$\^$T/+ MgO + TiO$_2$is average 1.9 wt%, it corresponds to leucogranite. Yuksipryeong two-mica leucogranite shows negative linear trend for TiO$_2$, Al$_2$O$_3$, FeO, Fe$_2$O$_3$, MgO, CaO, K$_2$O, P$_2$O$\_$5/, Rb, Ba, and Sr as SiO$_2$increases, and the positive relation of Zr and Th, which result from feldspar, biotite, apatite and zircon fractionation. Pegmatitic dike has higher SiO$_2$and P$_2$O$\_$5/, but lower another major elements. Yuksipryeong two-mica leucogranite has lower Rb, but higher Ba and Sr than Manaslu, Hercynian two-mica leucogranites, and S-type granites in Lachlan Fold Belt. Pegmatitic dike has higher Rb and Nb but lower Ba, Sr, Zr, Th, and Pb contents than Yuksipryeong two-mica leucogranite, resulting in removing or mobilizing for some trace elements from the granitic melt. Yuksipryeong two-mica leucogranite has total REEs with 95.7∼l23.3 ppm, and chondrite-normalized REE pattern is very steep ((La/Yb)$\_$N/ = 6.9∼24.8), light REEs (LREEs)-enriched End heavy REEs (HREEs)- depleted pattern with low to moderate Eu anomalies (Eu/Eu*= 0.7∼0.9). While pegmatitic dike has low total REEs with 7.0 ppm, and chondrite-normalized REE pattern is flat-pattern ((La/Yb)$\_$N/ = 2.1) with strong negative Eu anomalies (Eu/Eu*= 0.2). The melt compositions having formed two-mica leucogranites depend on not only the source rock but also the amounts of the residual remaining after melting of source rocks. The CaO/Na$_2$O and Rb/Sr-Rb/Ba ratios depend mainly on the composition of source rocks in the strongly peraluminous granite, that is, plagioclase/clay ratio of the source rocks. Yuksipryeong two-mica leucogranite has higher CaO/Na$_2$O and lower Rb/Sr-Rb/Ba ratios than Manaslu and Hercynian two-mica leucogranites (Millevaches and Gueret) derived from clay-rich, plagioclase-poor (polite), which suggest that the probable source rocks for Yuksipryeong two-mica leucogranite is clay-poor, plagioclase-rich quartzofeldspathic rocks. As the concentrations of Al$_2$O$_3$remain nearly constant but those of TiO$_2$increases as increasing temperature in the strong peraluminous melt, the Al$_2$O$_3$/TiO$_2$ratio may reflect relative temperature at which the melts have formed. Comparing the polite-derived Manaslu and Hercynian two- mica leucogranites, Manaslu two-mica leucogranite has higher Al$_2$O$_3$/TiO$_2$ratio than latter, and its melt have formed at relatively lower temperature ($\leq$ 875$^{\circ}C$) than Hercynian two-mica leucogranites. Likewise, comparing the quartzofeldspathic rock-derived granites, Yuksipryeong two-mica granite has higher Al$_2$O$_3$/TiO$_2$, ratio than S-type granites in Lachlan Fold Belt (>875$^{\circ}C$). The melt formed Yuksipryeong two-mica leucogranite are considered to have been formed at temperature at below the maximum 875$^{\circ}C$C$.

A Survey on Health Service Activities of Public Health Nurses in Inchon & Kyung Gi Area (인천.경기지역 보건소 간호사의 보건사업 수행에 관한 조사 연구)

  • Kim, Myeong-Sun
    • Research in Community and Public Health Nursing
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    • v.1 no.1
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    • pp.88-102
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    • 1989
  • This survey was conducted in order to find out the degree of health service activities of Public Health Nurses & variables relevant to their activities. The subjects of this survey were 232 PHN in Health Centers, Inchon & Kyung Gi area. Data were collected by mean of questionairs from 30th, September to 30th, October, 1986. For the analysis, ANOVA was used. The results were as follows; 1. General characteristics of PHN: o An approximately four fifth of the subjects (82.3%) was between 20-39 years. o The average career length of the subjects as PHN was 4 years. o Their educational level was almost Nursing School (22.4%) Junior College of Nursing (53.4%). o The marital status of the subjects was already married (75.4%). 3. The degree of health service activities of PHN; o The total mean of health service activities was 2.147 (S.D: 1.477, range 11-5). o Among the 11 Health Service Categories; Health service planning (2.828) is the highest mean scored category. The lowest mean scored category was the other health services. o Among the specific activity items about the 11 health service categories, the highest scored activities were 'personal counselling & education' in well-baby care (2.504), family planning (2.530), Tb control (2.134), disease control (2.371), 'health history taking & health examination', in prenatal care, 'clinic care', in administrative service, 'record & report', in the other categories. o Almost categories (10), 'Home visiting' was the lowest scored activity. 3. The relevance for the health service activities by several variables were as follows; o The relevance for the health service activities by general characteristics of PHN was not shown significance at age, educational level, marital status, relegion status. o And at work place, & work department was shown high significance.

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Effects of MgO content of Spinel on the Reaction of Spinel with CaO-Al$_2$O$_3$-SiO$_2$ Slag (CaO-Al$_2$O$_3$-SiO$_2$계 슬래그와 스피넬의 반응에 미치는 스피넬중의 MgO함유량의 영향)

  • 조문규;홍기곤
    • Journal of the Korean Ceramic Society
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    • v.36 no.4
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    • pp.410-416
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    • 1999
  • The reactivity of three kinds of spinels which CaO-Al2O3-SiO2 slag was investigated in terms of mineral phases and microstructures. New crystal products were not formed by reaction of 12CaO.7Al2O3 in the slag with spinels and free MgO components was preferenctially dissolved into slag for MgO-rich spinel and stoichiometric spinel. Meanwhile mineral phase was changed from 12CaO.7Al2O3 to CaO.Al2O3 to CaO.2Al2O3 finally to CaO.6Al2O3 having high melting point for Al2O3 -rich spinel. The Fe-oxide component of the slag was taken up by only stoichiometric spinel grains within the spinel clinker and the trapped amount of Fe-oxide was independent of MgO content of MgO in spinel clinker the more th resistance to slag corrosion but the less resistance to slag penetration.

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Decolorization of a Rhodamine B Using Photoelectrocatalytic and Electrolytic/UV Process (광전기촉매 공정과 전기/UV 공정을 이용한 Rhodamine B의 색 제거)

  • Kim, Dong-Seog;Park, Young-Seek
    • Journal of Environmental Science International
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    • v.17 no.9
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    • pp.1023-1032
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    • 2008
  • The feasibility study of the application of the photoelectrocatalytic and electrolytic/UV decolorization of Rhodamine B (RhB) was investigated in the photoelectrocatalytic and electrolytic/UV process with $TiO_2$ photoelectrode and DSA (dimensionally stable anode) electrode. Three types of $TiO_2$ photoelectrode were used. Thermal oxidation electrode (Th-$TiO_2$) was made by oxidation of titanium metal sheet; sol-gel electrode (5G-$TiO_2$) and powder electrode (P-$TiO_2$) were made by coating and then heating a layer of titania sol-gel and slurry $TiO_2$ on titanium sheet. DSA electrodes were Ti and Ru/Ti electrode. The relative performance for RhB decolorization of each of the photoelecoodes and DSA electrodes is: Ru/Ti > Ti > SG-$TiO_2$ > Th-$TiO_2$. It was observed that photoelectrocatalytic decolorization of RhB is similar to the sum of the photocatalytic and electrolytic decolorization. Therefore the synergetic effect was not showed in pthotoelectrocatalytic reaction. $Na_{2}SO_{4}$ and NaCl showed different decolorization effect between pthotoelectrocatalytic and electrolytic/UV reaction. In the presence of the NaCl, RhB decolorization of Ru/Ti DSA electrode was higher than that of the other photoelectrode and Ti electrode. Optimum current, NaCl dosage and UV lamp power of the electrolytic/UV process (using Ru/Ti electrode) were 0.75 A, 0.5 g/L and 16 W, respectively.

COMPARISON BETWEEN EXPERIMENTALLY MEASURED AND THERMODYNAMICALLY CALCULATED SOLUBILITIES OF UO2 AND THO2 IN KURT GROUND WATER

  • Kim, Seung-Soo;Baik, Min-Hoon;Kang, Kwang-Cheol;Choi, Jong-Won
    • Nuclear Engineering and Technology
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    • v.41 no.6
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    • pp.867-874
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    • 2009
  • Solubility of a radionuclide is important for defining the release source term of a radioactive waste in the safety and performance assessments of a radioactive waste repository. When the pH and redox potential of the KURT groundwater were changed by an electrical method, the concentrations of uranium and thorium released from $UO_2$(cr) and $ThO_2$(cr) at alkali pH(8.1 ${\sim}$ 11.4) and reducing potential (Eh < -0.2 V) conditions were less than $10^{-7}mole/L$. Unexpectedly, the concentration of tetravalent thorium is slightly higher than that of uranium at pH = 8.1 and Eh= -0.2 V conditions, and this difference may be due to the formation of hydroxide-carbonate complex ions. When $UO_2$(s) and $UO_2$(am, hyd.), and $ThO_2$(s) and $Th(OH)_4(am)$ were assumed as solubility limiting solid phases, the concentrations of uranium and thorium in the KURT groundwater calculated by the PHREEQC code were comparable to the experimental results. The dominating aqueous species of uranium and thorium were presumed as $UO_2(CO_3)_3^{4-}$ and $Th(OH)_3CO_3^-$ at pH = 8.1 ${\sim}$ 9.8, and $UO_2(OH)_3^-$ and $Th(OH)_4(aq)$ at pH = 11.4.

A Comparative Study of Douchi Hataedock versus Omega-3 on the Effect of Anti-inflammation in the Colonic Muscle through Th2 Skewed Condition Control (Th2 skewed condition 조절을 통한 대장점막 내 염증개선효과에 대한 두시 하태독법과 오메가3 비교 연구)

  • Ahn, Sang Hyun;Kim, Ki Bong
    • The Journal of Pediatrics of Korean Medicine
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    • v.31 no.3
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    • pp.37-45
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    • 2017
  • Objectives Hataedock is an orally-administered herbal extract that used to treat toxic heat and help excrete meconium accumulates in the fetus from pregnancy. This study compared the effects of Hataedock using the extract of Douchi and omega-3 to control inflammation in the colonic mucosa. Methods NC/Nga mice were divided into three groups; Control group (no treatment), FGT group (given the extract of Douchi), and O3T group (given omega-3). The 3-week-old mouse from each group were given the extract of Douchi and omega-3. After 2 weeks, the colonic mucosa tissues of the mice were observed via Immunohistochemical staining for IL-4, IL-13, CD40, $Fc{\varepsilon}RI$, $p-I{\kappa}B$, EGF in the intestinal mucosa. Results In both FGT and O3T group, IL-4, IL-13, STAT-6 levels and CD40-positive reactions were decreased. However, EGF-positive responses were increased. FGT group showed 35% decrease in IL-4, 45% decrease in IL-13, 48% decrease in CD40, 50% decrease in $Fc{\varepsilon}RI$, 54% decrease in $p-I{\kappa}B$, 52% increase in EGF compared to the control group. O3T group also showed 14% decrease in IL-4, 23% decrease in IL-13, 22% decrease in CD40, 29% decrease in $Fc{\varepsilon}RI$, 41% decrease in $p-I{\kappa}B$, 39% increase in EGF compared to the control group. Conclusions Both early administration of Douchi extract and omega-3 were effective in regulating Th2, relieving inflammation and developing colonic mucosal tissues. Hataedock with Douchi extract may be more effective in modulating immune system in colonic mucosa than omega-3.