• 제목/요약/키워드: $V_{2}O_{5}$ addition

검색결과 390건 처리시간 0.033초

사과가공부산물 첨가배지가 팽이버섯(Flammulina velutipes)의 균사생장과 자실체에 미치는 영향 (Effects of Addition of Apple pomace to sawdust substrate on the Growth and Development of Flammulina velutipes)

  • 조우식;윤영석;유영현;박선도;최부술
    • 한국균학회지
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    • 제24권3호통권78호
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    • pp.223-227
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    • 1996
  • 팽이버섯 병 재배에 있어서 사과가공부산물의 첨가효과를 시험한 결과 배지재료별 화학적 특성은 사과가공부산물이 톱밥보다 산도(pH)가 낮았으며 T-N, $P_2O_5$, CaO, MgO는 비슷하였으나 T-C는 사과가중부산물이 다소 높았다 톱밥+미강배지에 사과가공부산물을 첨가하여 균사생장정도를 조사한 결과, 사과가공부산물 $5{\sim}20%$ 처리구는 톱밥+미강 20% 배지와 비슷하였으나 사과가공부산물 50%, 80% 처리구에는 pH가 5.1, 4.7로 강산성을 나타내어 균사생장이 불량하였다. 초발이 소요일수는 톱밥+미강 20% 처리구는 사과가공부산물 $5{\sim}20%$ 처리구의 $10{\sim}20$일과 비슷한 경향을 나타내었다. 배지종류별 수량을 보면 팽이버섯 재배에서 톱밥 사용량의 15%를 사과가공부산물로 대체 사용시 9%정도 증수되었다. 경제성 분석결과 톱밥사용량의 15%를 사과기공부산물로 대체 사용 시 소득지수가 29% 높게 나타났다.

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$V_2O_5$ 도핑한 페라이트 페이스트 후막 특성 (Properties of Thick Films Prepared with $V_2O_5$-doped Ferrite Pastes)

  • 제해준;김병국;박재환;박재관
    • 한국결정학회지
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    • 제12권2호
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    • pp.70-75
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    • 2001
  • NiCuZn 페라이트에 V₂O/sub 5/가 0∼0.5 wt% 첨가된 페이스트를 사용하여 스크린 인쇄법으로 페라이트 후막을 제조한 후, 870∼900℃에서 소결하여 V₂O/sub 5/ 첨가량에 따른 소결밀도, 미세구조 등의 물리적 특성 및 자기적 특성 변화를 분석하였다. 소결온도 870℃의 경우 V₂O/sub 5/를 0.5 wt% 첨가한 시편의 소결밀도가 0.58 g/cm³로 가장 hsvrp 나타낫고, 소결온도가 올라갈수록 소결밀도 차이가 줄어들어 900℃의 경우 모든 시편이 5.15g/cm³이상으로 높은 밀도를 나타내었다. V₂O/sub 5/가 0.5 wt% 첨가된 경우에 액상소결이 발달하였으며, V₂O/sub 5/가 0.1, 0.3 wt% 첨가된 시편은 입자성장이 억제되어 입자크기가 V₂O/sub 5/를 첨가하지 않은 시편보다 작았다. 전체의 소결온도 범위에서 V₂O/sub 5/가 첨가되지 않은 시편의 입자크기가 크고 균일하기 때문에 투자율이 가장 높게 나타났으며, 소결온도 880℃ 이상에서 V₂O/sub 5/ 0.3 wt% 첨가 시편의 Q값이 가장 높은 것으로 나타났다. 결론적으로 칩 인덕터용 NiCuZn 페라이트 소재 제조 시, 투자율값을 중시할 경우에는 V₂O/sub 5/를 첨가하지 않아야 하며, 품질계수를 중시할 경우에는 V₂O/sub 5/의 첨가량이 0.3wt%를 넘지 않아야 함을 알 수 있었다.

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Catalytic Reactions of Ethanol over $TiO_2$-supported Vanadia Catalysts

  • Jeon, Byung-Wook;Kim, Yu-Kwon
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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    • pp.284-284
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    • 2012
  • In this study, $V_2O_5/TiO_2$ catalyst was measured reactivity of ethanol when vanadia ratio was increasing. First, $V_2O_5/TiO_2$ catalyst was prepared to the increasing vanadia ($VO_x$) ratio as 0.2, 1, 10 wt%. And we were used X-ray diffraction (XRD), then not appear markedly peak to pure vanadia about XRD analysis. So we were decided vanadia that was evenly dispersed on $TiO_2$. Result about temperature-programmed reduction (TPR) analysis was obtained 3 reactions that was dehydrogenationfrom obtained to acetaldehyde, dehydration from obtained to ethylene, condensation from obtained to diethyl ether. If vanadia ratio was increasing in $V_2O_5/TiO_2$, reactions temperature of ethanol was known lower. And condensation into diethyl ether is quenched away with increasing vanadia loading. In addition, competition between reductive dehydration and oxidative dehydrogenation occurs, while the selectivity toward dehydrogenation is favored with increasing vanadia loading.

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$ZnWO_4$ 소결특성 및 고주파 유전특성 (Sintering and Microwave Dielectric Properties of $ZnWO_4$)

  • 이경호;김용철
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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    • pp.386-389
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    • 2001
  • In this study, development of a new LTCC material using non-glassy system was attempted with repsect to reducing the fabrication process steps and cost down. Lowering the sintering temperature can be achieved by liquid phase sintering. However, presence of liquid phases usually decrease dielectric properties, especially the quality factor. Therefore, the starting material must have quality factor as high as possible in microwave frequency range. And also, the material should have a low dielectric constant for enhancing the signal propagation speed. Regarding these factors, dielectric constants of various materials were estimated by the Clausius-Mosotti equation. Among them, $ZnWO_4$ was turned out the suitable LTCC material. $ZnWO_4$ can be sintered up to 98% of full density at $1050^{\circ}C$ for 3 hours. It's measured dielectric constant, quality factor, and temperature coefficient of resonant frequency were 15.5, 74380GHz, and $-70ppm/^{\circ}C$, respectively. In order to modify the dielectric properties and densification temperature, $B_{2}O_{3}$ and $V_{2}O_{5}$ were added to $ZnWO_4$. 40 mol% $B_{2}O_{3}$ addition reduced the dielectric constant from 15.5 to 12. And the temperature coefficient of resonant frequency was improved from -70 to $-7.6ppm/^{\circ}C$. However, sintering temperature did not change due to either lack of liquid phase or high viscosity of liquid phase. Incorporation of small amount of $V_{2}O_{5}$ in $ZnWO_{4}-B_{2}O_{3}$ system enhanced liquid phase sintering. 0.1 wt% $V_{2}O_{5}$ addition to the $0.6ZnWO_{4}-0.4B_{2}O_{3}$ system, reduced the sintering temperature down to $950^{\circ}C$. Dielectric constant, quality factor, and temperature coefficient of resonant frequency were 9.5, 16737GHz, and $-21.6ppm/^{\circ}C$, respectively.

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$ZnWO_4$ 소결특성 및 고주파 유전특성 (Sintering and Microwave Dielectric Properties of $ZnWO_4$)

  • 이경호;김용철
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 추계학술대회 논문집
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    • pp.386-389
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    • 2001
  • In this study, development of a new LTCC material using non-glassy system was attempted with respect to reducing the fabrication process steps and cost down. Lowering the sintering temperature can be achieved by liquid phase sintering. However, presence of liquid phases usually decrease dielectric properties, especially the quality factor. Therefore, the starting material must have quality factor as high as possible in microwave frequency range. And also, the material should have a low dielectric constant for enhancing the signal propagation speed. Regarding these factors, dielectric constants of various materials were estimated by the Clausius-Mosotti equation. Among them, ZnWO$_4$ was turned out the suitable LTCC material. ZnWO$_4$ can be sintered up to 98% of full density at 105$0^{\circ}C$ for 3 hours. It's measured dielectric constant, quality factor, and temperature coefficient of resonant frequency were 15.5, 74380GHz, and -70ppm/$^{\circ}C$, respectively In order to modify the dielectric properties and densification temperature, B$_2$O$_3$ and V$_2$O$_{5}$ were added to ZnWO$_4$. 40 mol% B$_2$O$_3$ addition reduced the dielectric constant from 15.5 to 12. And the temperature coefficient of resonant frequency was improved from -70 to -7.6ppm/$^{\circ}C$. However, sintering temperature did not change due to either lack of liquid phase or high viscosity of liquid phase. Incorporation of small amount of V$_2$O$_{5}$ in ZnWO$_4$-B$_2$O$_3$ system enhanced liquid phase sintering. 0.lwt% V$_2$O$_{5}$ addition to the 0.6ZnWO$_4$-0.4B$_2$O$_3$ system, reduced the sintering temperature down to 95$0^{\circ}C$ Dielectric constant, quality factor, and temperature coefficient of resonant frequency were 9.5, 16737GHz, and -21.6ppm/$^{\circ}C$ respectively.ively.

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Single Crystalline ${\beta}$-Na0.33V2O5 Nanowires Based Supercapacitor

  • Trang, Nguyen Thi Hong;Shakir, Imran;Kang, Dae-Joon
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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    • pp.587-587
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    • 2012
  • Supercapacitors, which can deliver significant energy with high power density, have attracted a lot of attention due to their potential application in energy storage. Among various oxide materials, sodium vanadate has been recognized as one of the most promising electrode materials because of high electrical conductivity. In addition, larger layer spacing of ${\beta}$-Na0.33V2O5 compared to V2O5 makes easier Li+ insertion. Moreover, ${\beta}$-Na0.33V2O5 has a tunnel like structure along b axis with 3 kinds of V site allowing it to enhance the ion intercalation by introducing three different intercalation sites along the tunnel. The tunnel can act as a fast diffusion path for ion diffusion, which can improve the overall charge storage kinetics. In this study, high quality single crystalline sodium vanadate (${\beta}$-Na0.33V2O5) nanowires were grown directly on Pt coated $SiO_2$ substrate by a facile chemical solution deposition method without employing catalyst, surfactant or carrier gas. The results show that great enhancement in capacitance was observed compared with previous reports.

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$CuO-V_2O_5-TeO_2$계 결정화 유리의 전기적특성 (Electrical Properties of $CuO-V_2O_5-TeO_2$ Glass-Ceramics)

  • 이창희;손명모;이헌수;구할본;박희찬
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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    • pp.842-844
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    • 2004
  • Ternary tellurite glassy systems $(CuO-V_2O_5-TeO_2)$ have been synthesised using tellurium oxide as a network former and copper oxide as network modifier. The addition of a transition-matal oxide makes them electric or mixed electric-ionic conductors, which are of potential interest as cathode materials for solid-state batteries. This glass-ceramics crystallized from the $CuO-V_2O_5-TeO_2$ system are particularly interesting, because they exhibit high conductivity ( up to $6.03{\times}10^{-3}S/cm$) at room temperature. the glass samples were prepared by quenching the melt on the copper plate and the glass-ceramics were heat-treated at crystallizing temperature determined from differential thermal analysis (DTA). The electric D.C conductivity result have been analyzed in terms of a small polaron-hopping model.

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$V_2O_5$를 dopant로 한 $TiO_2$의 감습(感濕)에 미치는 $M_2CO_3$(M=Li, K)의 영향(影響) (Effect of $M_2CO_3$(M=Li, K) Addition on the Humidity Sensitivity of $V_2O_5$-doped $TiO_2$)

  • 강이국;송창열;신용덕
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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    • pp.427-429
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    • 1995
  • In this paper, the effect of alkaline oxides on the humidity sensitivity of $V_2O_5$(2mol%)-doped $TiO_2$(98mol%) was investigated as functions of $Li_2CO_3$, $K_2CO_3$, additives (x= 0.0 mol%, 1mol%, 2mol%, 5mol%, 10mol%). 1. The porosity and total intrusion volume of sample containing 1, 2, 5mol% $K_2O$ was increased, and then those of 10mol% $K_2O$ was reduced again. 2. The humidity sensitivity of samples containing 1, 2, 5, 10mol% $K_2O$ were good generally. Especially the sample containing 5mol% $K_2O$ were the better. 3. the stability of the humidity sensitivity of samples containing $K_2O$ at low and high temperatures is very good.

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Electrochemical Characteristics of Lithium Vanadium Oxide for Lithium Secondary Battery

  • Kim, Hyung-Sun;Cho, Byung-Won
    • Bulletin of the Korean Chemical Society
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    • 제31권5호
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    • pp.1267-1269
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    • 2010
  • The pure crystalline $Li_{1.1}V_{0.9}O_2$ powder has been prepared by a simple solid state reaction of $Li_2CO_3$ and $V_2O_3$ precursors under nitrogen gas containing 10 mol % hydrogen gas flow. The structure of $Li_{1.1}V_{0.9}O_2$ powder was analyzed using Xray diffraction (XRD) and scanning electron microscope (SEM). The stoichiometric $Li_{1.1}V_{0.9}O_2$ powder was used as anode active material for lithium secondary batteries. Its electrochemical properties were investigated by cyclic voltammetry and constant current methods using lithium foil electrode. The observed specific discharge capacity and charge capacity were 360 mAh/g and 260 mAh/g during the first cycle, respectively. In addition, the cyclic efficiency of this cell was 72.2% in the first cycle. The specific capacity of $Li_{1.1}V_{0.9}O_2$ anode rapidly declines as the current rate increases and retains only 30 % of the capacity of 0.1C rate at 1C rate. The crystallinity of the $Li_{1.1}V_{0.9}O_2$ anode decrease as discharge reaction proceeds. However, the relative intensity of main peaks was almost recovered when the cell was charged up to 1.5 V.

B2O3첨가에 따른 V2O5-P2O5-ZnO계 유리의 물성 및 구조와 봉착특성 (Effect of B2O3 Addition on Thermal, Structure, and Sealing Properties V2O5-P2O5-ZnO Glass)

  • 성아람;김유리안;김형순
    • 한국재료학회지
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    • 제26권10호
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    • pp.549-555
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    • 2016
  • We have investigated a glass-forming region of $V_2O_5-P_2O_5-ZnO$ glass and the effects of the addition of modifier oxides ($B_2O_3$) to the glass systems as a sealing material to improve the adhesion between the glass frits and a soda lime substrate. Thermal properties and coefficient of thermal expansion were measured using a differential scanning calorimetry, a dilatometer and a hot stage microscopy. Structural changes and interfacial reactions between the glass substrate and the glass frit after sintering (at $400^{\circ}C$ for 1 h) were measured by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscope. The results showed that the adhesion strength increases as the content of $B_2O_3$ at 5 mol% increases because of changes in the structural properties. It seems that the glass structures change with $B_2O_3$, and the $Si^{4+}$ ions from the substrate are diffused to the sealing glass. From these results, we could understand the mechanism of strengthening of the adhesion of soda lime silica substrate by ion-diffusion from the substrate to the glass.