• Title/Summary/Keyword: $PbO_2$

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Piezoelectric and Dielectric Properties of Low Temperature Sintered Pb(Mn1/3Nb2/3)0.02(Ni1/3Nb2/30.12(ZrxTi1-x)0.86O3 System Ceramics

  • Yoo, Ju-Hyun;Lee, Sang-Ho
    • Transactions on Electrical and Electronic Materials
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    • v.10 no.4
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    • pp.121-124
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    • 2009
  • In this study, in order to develop compositions of ceramics suitable for piezoelectric actuator and ultrasonic vibrator applications using low temperature sintering, multilayer, PMN-PNN-PZT ceramics were fabricated using $Li_2CO_3$ and $Na_2CO_3$ as sintering aids. Their structural, piezoelectric and dielectric characteristics were investigated according to the Zr/Ti ratio. As the Zr/Ti ratio increased, the electromechanical coupling factor $k_p$, and piezoelectric constant $d_{33}$ and the mechanical quality factor $Q_m$ all increased with Zr/Ti ratio and then decreased after the ratio exceeded 50/50. At the ratio of Zr/Ti =49/51 and sintering temperature of $900^{\circ}C$; the density, electromechanical coupling factor $k_p$, dielectric constant ${\varepsilon}_r$ piezoelectric $d_{33}$ constant and mechanical quality factor $Q_m$ all showed the optimum values of 7.900 $g/cm^3$, 0.576, 856, 312 pC/N, 1,326, respectively. These property values are very suitable for multilayer ceramics actuator applications.

Piezoelectric and Dielectric Properties of PMN-PNN-PZT Ceramics for Ultrasonic Generator with Calcination Temperature (하소온도변화에 따른 초음파절삭기용 PMN-PNN-PZT 세라믹스의 압전 및 유전 특성)

  • Yoo, Ju-Hyun;Kim, Seung-Won;Seo, Dong-Hi;Lee, Eun-Sup;Choi, Nak-Gu;Jeong, Hoy-Seung
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.30 no.3
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    • pp.152-156
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    • 2017
  • In this paper, $Pb(Mn_{1/3}Nb_{2/3})_{0.07}(Ni_{1/3}Nb_{2/3})_{0.10}(Zr_{0.5}Ti_{0.5})_{0.83}O_3$ ceramics were fabricated by the conventional solid state method to obtain excellent dielectric properties for ultrasonic generators. The effects of 2nd calcination temperature on their microstructure and piezoelectric properties were systematically investigated. The tetragonality increased in the ceramics when 2nd calcination temperature increased to the optimized temperature at $750^{\circ}C$. At that temperature, excellent physical properties ($d_{33}=352\;pC/N$, ${\varepsilon}_r=1,687$, $k_p=0.570$, $Q_m=1,640$) were obtained for ultrasonic generator application.

Piezoelectric and Electric Field Induced Strain Properties of PMW-PNN-PZT Ceramics with the Substitution of Ba (Ba 치환에 따른 PMW-PNN-PZT 세라믹스의 압전 및 전계유기왜형 특성)

  • 윤광희;김규수;최병수
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.14 no.1
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    • pp.20-25
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    • 2001
  • To develop the piezoelectric actuator, the structural, dielectric and piezoelectric properties and electric fieldinduced strain of the ceramics(Pb$\_$1-2/Ba$\_$x/)[Mg$\_$1/2/W$\_$1/2/)$\_$0.03/-Ni$\_$1/3/Nb$\_$2/3/)$\_$0.12/-(Zr$\_$0.5/Ti$\_$0.5/)$\_$0.85/]O$_3$(x=0, 0.01, 0.03, 0.05, 0.07, 0.1) were investigated with the substitution of Ba. The tetragonality of crystal structure and grain size decreased by the substitution of Ba. Curie temperature decreased due to the decrease of the tetragonality, and dielectric constants increased with the substitution of Ba. The coercive field, remnant polarization and electromechanical coupling factor also decreased, whereas the piezoelectric constatns d$\_$33/ and d$\_$31/ were showed the highest value of 430 and 209(x10$\^$-12/C/N), respectively, because of the increase of dielectric constant. The strain induced by 60Hz AC electric field had the maximum value of 204x10$\^$-6/Δℓ/ℓ at the substitution of Ba 3mol%. As the applied electric field approaches to the coercive field, the piezoelectric element is depolarized and the electric field induced strain revealed non-linearity.

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Color Characteristics of the Costumes of the Beijing Opera (중국 경극 의상의 색채특성)

  • Kim, Ji-Eon
    • Journal of the Korean Society of Costume
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    • v.59 no.2
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    • pp.143-153
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    • 2009
  • The purpose of this study is to provide color information in order to planning and merchandising in china fashion through the color of Beijing opera. In objective study, we collect total 302 Beijing opera images. The collecting method of source data is to extract digital color data by color picker. We transform RGB color data to H V/C, CIE L*a*b and analyze the attributes of color and tone, three-dimensional analysis. The results of this study are as follows : 1. The color distrbution of Beijing opera is R(26.9%)>YR(18.2%)>PB(11.6%)>Y(9.6%). Traditional preference color, red is most popular color as 26.7%:, the practice of vivid tone red is numerous. 2. The tone distribution of Beijing opera costume is P(16%)>It(13.9%)>d(11%)>5(9.6%)>4kg (8.2%)>b(7.1%:). The value o# Beijing opera costume distribute medium and medium-high and the chroma of those distributes low. 3. High chroma yellow is restrictive color as the symbol of emperor in china but medium-low chroma yellow is very frequently used. 4. Blue is often used in china costume. Especially in Beijing opera costume blue is symbol of bravery, dignity, cruel character 5. White in Beijing opera costume is much used for symbol of righteous loyalist. Black is less used than white in Beijing opera costume and black is authority color for symbol of the prime minister.

Preliminary Design for Preparing a Natural Learning and Experimental Area in Bukchun and Boundary(I) - Analysis of Riverbed, Atmospheric and Ecological Environment- (북천지역 자연학습 체험단지 초성을 위한 기본 계획(I) -하상분석, 대기질 및 생태분석-)

  • 정종현;최석규;조세환
    • Journal of Environmental Health Sciences
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    • v.28 no.2
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    • pp.23-39
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    • 2002
  • This study focuses on the structure of geographical conditions, the riverbed, the meterological and atmospheric examination, the ecological environment, the food chain and the ecosystem, in order to establish a basic plan for preparing a natural learning area of environmental ecosystem in Bukchun and its surroundings, Gyeongju. The results could be summarized as follows. Bukchun is a first grade which extends 6km along the road from Bomun bridge to the junction of Hyungsangang. The basin area is 7.10$\textrm{km}^2$ and the slope is 1/200~1/300. Gyeongju has good atmospheric conditions, i.e. SO$_2$0.011 ~0.017ppm, CO 0.8~ 1.5ppm, NO$_2$0.013~0.019ppm, $O_3$0.013~0.020ppm, TSP 85~142$\mu\textrm{g}$/㎥, PM-10 47~90$\mu\textrm{g}$/㎥ and Pb 0.057 ~0.129$\mu\textrm{g}$/㎥, which is below the annual and daily averages, and is little lower than those of Pohang and Ulsan. The ecosystem of Bukchun is based on the structure of the food chain, which includes birds such as the grey and white herons at the top of the food chain. This study also considers the development of the river's in terms of culture, environment and ecology concept.

Purification and Characterization of Hemagglutinating Protein from Rhizome of Alisma orientale (택사(Alismatis Rhizoma) Hemagglutinating Protein의 정제와 특성)

  • 박종옥;김경순;선우근옥
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.24 no.4
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    • pp.587-593
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    • 1995
  • Lectin was purified by using $(NH_4)_2SO_4$, DEAE-cellulose ion-exchange chromatography and Sephadex G-150 column chromatography from Alismatis Rhizoma(AR). The specific activity of AR lectin was 50, 441units/mg, and purification folds were 114. The AR lectin agglutinated human erythrocytes of all types(A, B, O, AB). The molecular weight of AR lectin was estimated about 90, 500 daltons by gel filtration and each subunits were 42,000, 27,000 and 22,500 daltons on SDS-PAGE respectively. The hemagglutinating activity of the lectin was inhibited by sialic acid, glucose, ribose, galactose, sucrose, and lactose. It was also inhibited by cations such as $Hg^{++},\;Fe^{++},\;Cu^{++}\;and\;Pb^{++}$.

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Highly Efficient Flexible Perovskite Solar Cells by Low-temperature ALD Method

  • Kim, Byeong Jo;Kwon, Seung Lee;Jung, Hyun Suk
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.469.2-469.2
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    • 2014
  • All-solid-state solar cell based on Chloride doped organometallic halide perovskite, (CH3NH3)PbIxCl3-x, has achieved a highly power conversion efficiency (PCE) to over 15% [1] and further improvements are expected up to 20% [2]. In this way, solar cells using novel light absorbing perovskite material are actively being studied as a next generation solar cells. However, making solution-process require high temperature up to $500^{\circ}C$ to form compact hole blocking layer and sinter the mesoporous oxide scaffold layer. Because of this high temperature process, fabrication of flexible solar cells on plastic substrate is still troubleshooting. In this study, we fabricated highly efficient flexible perovskite solar cells with PCE in excess of 11%. Atomic layer deposition (ALD) is used to deposit dense $TiO_2$ as hole blocking layer on ITO/PEN substrate. The all fabrication process is done at low temperature below $150^{\circ}C$. This work shows that one of the important blueprint for commercial use of perovskite solar cells.

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Development of joining process of the BSCCO(2223)/Ag multi-filament tapes (BSCCO(2223)/Ag 다심 초전도선재의 접합공정 개발)

  • Kim, Kyu-Tae;Kim, Jung-Ho;An, Hyuck;Jang, Seok-Hern;Joo, Jin-Ho
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2003.02a
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    • pp.120-122
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    • 2003
  • We jointed Bi(Pb)-Sr-Ca-Cu-O multifilament tapes and evaluated their electrical properties. In order to improve connectivity of multifilarnents, single-filament tape was inserted between two multifilament tapes or multifilament was stepped by mechanical remove. The critical current ratio (CCR) and n-value of the jointed tapes were evaluated as a function of uniaxial pressure. It was observed that CCR and n-value were 24.8-29.0% and 2.5-2.8 for lap-jointed tape. On the other hand, the corresponding values were improved to 51.8-61.9% and 2.9-5.1 for three stepped jointed tape, and 63.4-67.9% and 3.4-4.2 for double MSM lap-jointed tape, respectively. These improvements are to be due to better interconnection between filaments of two tapes.

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Piezoelectric and dielectric properties of PMN-PZN ceramics for multilayer piezoelectric transformer with PZN substitution (PZN 치환에 따른 적층 압전변압기용 PMN-PZT 세라믹의 압전 및 유전 특성)

  • Lee, Chang-Bae;Yoo, Ju-Hyun;Paik, Dong-Soo;Im, In-Ho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.59-61
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    • 2005
  • In this paper, in order to develop the low temperature sintering ceramics for multilayer piezoelectric transformer, $Pb[(Mn_{1/3},Nb_{2/3})_{0.07}(Zn_{1/3}Nb_{2/3})_a(Zr_{0.48}Ti_{0.52})_{1-0.07-a}O_3]$ ceramics were manufactured with the variations of PZN from 2 to 14mol% and their dielectric and piezoelectric properties were investigated. Sintering temperature was varied from 910 to $1000^{\circ}C$. At 8mol% PZN substituted specimen sintered at $970^{\circ}C$, electromechanical coupling factor(kp), mechanical quality factor(Qm), dielectric constant and peizoelectric constant($d_{33}$) showed the optimal values of 0.536, 1803, 1551 and 328[pC/N), respectively, for multilayer piezoelectric transformer application.

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Comparison of Abnormal Grain Growth Behavior of Lead-Free (Na,K)NbO3-M(Cu,Nb)O3, (M = Ca, Sr, Ba) Piezoelectric Ceramics (비납계 (Na,K)NbO3-M(Cu,Nb)O3, (M = Ca, Sr, Ba) 압전 세라믹의 비정상 결정 성장 거동 비교)

  • Jung, Seungwoon;Lim, Ji-Ho;Jung, Han-Bo;Ji, Sung-Yub;Choi, Seunggon;Jeong, Dae-Yong
    • Korean Journal of Materials Research
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    • v.30 no.7
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    • pp.343-349
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    • 2020
  • NKN [(Na,K)NbO3] is a candidate lead-free piezoelectric material to replace PZT [Pb(Zr,Ti)O3]. A single crystal has excellent piezoelectric-properties and its properties are dependent of the crystal orientation direction. However, it is hard to fabricate a single crystal with stoichiometrically stable composition due to volatilization of sodium during the growth process. To solve this problem, a solid solution composition is designed (Na,K)NbO3-Ba(Cu,Nb)O3 and solid state grain growth is studied for a sizable single crystal. Ceramic powders of (Na,K)NbO3-M(Cu,Nb)O3 (M = Ca, Sr, Ba) are synthesized and grain growth behavior is investigated for different temperatures and times. Average normal grain sizes of individual specimens, which are heat-treated at 1,125 ℃ for 10 h, are 6.9, 2.8, and 1.6 ㎛ for M = Ca, Sr, and Ba, respectively. Depending on M, the distortion of NKN structure can be altered. XRD results show that (NKN-CaCuN: shrunken orthorhombic; NKN-SrCuN: orthorhombic; NKN-BaCuN: cubic). For the sample heat-treated at 1,125 ℃ for 10 h, the maximum grain sizes of individual specimens are measured as 40, 5, and 4,000 ㎛ for M = Ca, Sr, and Ba, respectively. This abnormal grain size is related to the partial melting temperature (NKN-CaCuN: 960 ℃; NKN-SrCuN: 971 ℃; NKN-BaCuN: 945 ℃).