• 제목/요약/키워드: $Nb_2_O3$

검색결과 1,400건 처리시간 0.029초

Screen Printing법을 이용한 PMN-PZT 후막의 제조 및 특성 연구 (Fabrication and Characterization of PMN-PZT Thick Films Prepared by Screen Printing Method)

  • 김상종;최형욱;백동수;최지원;김태송;윤석진;김현재
    • 한국전기전자재료학회논문지
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    • 제13권11호
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    • pp.921-925
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    • 2000
  • Characteristics of Pb(Mg, Nb)O$_3$-Pb(Zr, Ti)O$_3$system thick films fabricated by a screen printing method were investigated. The buffer layer were coated with various thickness of Ag-Pd by screen printing to investigate the effect as a diffusion barrier and deposited Pt as a electrode by sputtering on Ag-Pb layer. The printed thick films were burned out at 650$\^{C}$ and sintered at 950$\^{C}$ in O$_2$condition for each 20, 60min after printing with 350mesh screen. The thickness of piezoelectric thick film was 15∼20㎛ and Ag-Pb layer acted as a diffusion barrier above 3㎛ thickness. The PMN-PZT thick films were screen printed on Pt/Ag-Pb(6m) and sintered by 2nd step (650$\^{C}$/20min and 950$\^{C}$/1h) using paste mixed PMN-PZT and binder in the ratio of 70:30, and the remnant polarization of thick film was 9.1$\mu$C/㎠ in this conditions.

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탄성파지연선에 관한 연구(II) (A Study on the Elastic Wave Delay Line (II))

  • 김종상
    • 대한전자공학회논문지
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    • 제13권2호
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    • pp.1-4
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    • 1976
  • LiN103의 X캇트판의 공진주파수의 온도특성을 구하는 이론적 방법을 제안하고 계산결과 공진주파수의 온도계수가 -78.43x10-0/℃임을 알았다. In this paper, temperature dependence of the resonant frequency of thickness shear mode in X cut plate of Li.NbO3 is theoretically analyzed. An a result of this analysis, theoretical value -78.43×10-6/℃ of the temperature coefficient of resonant frequency is obtained.

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PNST세라믹스의 유전 및 변형특성에 관한 연구 (A Study on the Dielectric and Strain Properties of PNST Ceramics)

  • 김진수;이덕출
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1998년도 춘계학술대회 논문집
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    • pp.331-334
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    • 1998
  • The solid solutions of the Pb(Sc$\_$0.5/Nb$\_$0.5/)$\_$0.57/Ti$\_$0.43/O$_3$ system were prepared. In the PSNT system, it had been known that two-phase region between the rhombohedral and tetragonal phases was observed between 0.425 of PT at room temperature. In this paper, Fe$_2$O$_3$-doped 0.57PSN-0.43PT composition was prepared by conventional method. The dielectric and strain properties were examined using an computerized measuring apparatus, and the resonance characteristics were measured using an impedance gain phase analyzer. We got the data of dielectric constant, dielectric loss, piezoelectric coefficient, piezoelectric voltage coefficient, frequency constant strain constant mechanical quality factor and electromechanical coupling factor.

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Cr+Fe 첨가시 PAN-PZT계 세라믹의 전기적 특성에 미치는 영향 (The effect on the electric characteristics of PAN-PZT ceramics dopped with Cr+Fe)

  • 신혜경;김현철;허석현;김진섭;배선기
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2000년도 추계학술대회 논문집
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    • pp.251-254
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    • 2000
  • This paper was to measure the structure, electric characteristics of 0.05Pb($(Al_{0.5}Nb_{0.5})$) - 0.95Pb$(Zr_{0.52}Ti_{0.48})O_3$ ceramics dopped with Cr+Fe. The results of this paper were gotten such as follows; The dielectric constants were decreased with Cr+Fe. The dielectric loss was minimum value of 1.008[%], dopped with Cr+Fe O.9[wt%] at 1200[$^{\circ}C$], In case of sintering at 1150[$^{\circ}C$], electromechanical factodkp) was maximum value of kp 42.73[%], at Cr+Fe 0.9[wt%]. The mechanical quality factor(Qm) was maximum value at Cr+Fe 1.2 [wt%], Also, in case of dopped with Cr+Fe, it make a improvement in temperature coefficient of resonant frequency at 0.3[wt%], 1150[$^{\circ}C$].

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Magneetoelastic Resonators에 사용되는 새로운 비정질 함금 (Devised New Amorphous Alloys for Magneetoelastic Resonators)

  • 김창경;유충근; R.C. O'Handley
    • 한국표면공학회지
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    • 제31권5호
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    • pp.245-250
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    • 1998
  • There is clear pressing need to reduce bias field(Ha,) used on linear magenetomechanical resonator tag by at least a factor of two to allow low-bias operation near the frequency minimum since reducing Ha causes a dramatic increase in well depth, which implies increased stability. However, this makes it more difficult to maintain tight frequncy specs. It can be solved by a reduction of magnetomechanical coupling(k). We determined from an equivalent circuit model that optimal reduced, k, is near 0.3 Also, We determiend the material properties($lambda_s$, :saturated magenetostriction, $M_s$, and,$H_a$) that give k=0.3. From these evaluations, we suggested that on optimal comosition with adequate mathrial properties is $Fe_{55}Co_{15}Cr_6Nb_2B_{18}Si_4$.

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Influence of Deposition Method on Refractive Index of SiO2 and TiO2 Thin Films for Anti-reflective Multilayers

  • Song, Myung-Keun;Yang, Woo-Seok;Kwon, Soon-Woo;Song, Yo-Seung;Cho, Nam-Ihn;Lee, Deuk-Yong
    • 한국세라믹학회지
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    • 제45권9호
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    • pp.524-530
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    • 2008
  • Anti-Reflective (AR) thin film coatings of $SiO_2$ (n= 1.48) and $TiO_2$ (n=2.17) were deposited by ion-beam assisted deposition (IBAD) with End-Hall ion source and conventional electron beam (e-beam) evaporation to investigate the effect of deposition method on the refractive indicies (n) of the fIlms. Green-light generation using a GaAs laser diode was achieved via excitation of the second harmonic. The latter resulted from the transmission of the fundamental guided-mode wave of 1064 nm through periodically poled $LiNbO_3$. Large differences in the refractive indicies of each of the layers in the multilayer coating may improve AR performance. IBAD of $SiO_2$ reduced its refractive index from 1.45 to 1.34 at 1064 nm. Conversely, e-beam evaporation of $TiO_2$ increased its refractive index from 1.80 to 2.11. In addition, no fluctuations in absorption at the wavelength of 1064 nm were found. The results suggest that films prepared by different deposition methods can increase the effectiveness of multilayer AR coatings.

A Low-noise Double Relaxation Oscillation SQUID Magnetometer for Measuring Magnetoencephalogram

  • 강찬석;이용호;권혁찬;김진목;윤병운
    • Progress in Superconductivity
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    • 제3권2호
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    • pp.151-158
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    • 2002
  • We developed a useful SQUID magnetometer for biomagnetic applications, magnetoencepha-logram(MEG) and magnetocardiogram(MCG), etc. The SQUIDs are based on Double Relaxation Oscillation SQUID(DROS). DROS consists of two SQUIDs(signal SQUID and reference SQUID) in series, and a relaxation circuit of an inductor and a resistor. Specially we used single reference junction instead of the reference SQUID. The SQUIDs are based on hysteretic $Nb/AlO_{x}$Nb junctions, fabricated by using a simple four level process. Because DROS magnetometer has large flux-to-voltage transfer coefficient, we can use simple flux-locked loop electronics fur SQUID operation. When the DROS magnetometer was operated inside a magnetically shielded room, its average magnetic field noise was about 3 (equation omitted) at 100 Hz. This noise level is low enough to measure biomagnetic fields. In this paper, we describe noise characteristics of DROS magnetometer, depending on the operation condition . .

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유기금속열분해 방법으로 제작된 NKN 박막의 강유전특성 (Ferroelectric properties of NKN Thin Films prepared by Metal Organic Decomposition method)

  • 김경태;김창일;이성갑
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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    • pp.1394-1395
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    • 2006
  • $(Na_{0.5}LaK_{0.5})NbO_3$ (NKN) thin films were fabricated by the alkoxide-based MOD method. NKN stock solutions were made spin-coated onto the Pt/Ti/$SiO_2$/Si substrate. The structural properties of the NKN thin films examined by x-ray diffraction. The perovskite phase was obtained as a function of the annealing temperature from $550^{\circ}C$ to $700^{\circ}C$ for 1h. The crystallinity and grain size of the NKN thin films increased with increasing annealing temperature. The dielectric constants and loss of the NKN thin films annealed at $650^{\circ}C$ ($t_{eq}$=2.35 nm) showed 323 and 0.025.

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Influence of Sintering Atmosphere on Abnormal Grain Growth Behaviour in Potassium Sodium Niobate Ceramics Sintered at Low Temperature

  • Fisher, John G.;Choi, Si-Young;Kang, Suk-Joong L.
    • 한국세라믹학회지
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    • 제48권6호
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    • pp.641-647
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    • 2011
  • The present study aims to identify the effect of sintering atmosphere [$O_2$, 75$N_2$-25 $H_2$ (mol%) and $H_2$] on microstructural evolution at the relatively low sintering temperature of 1040$^{\circ}C$. Samples sintered in $O_2$ showed a bimodal microstructure consisting of fine matrix grains and large abnormal grains. Sintering in 75 $N_2$ - 25 $H_2$ (mol %) and $H_2$ caused the extent of abnormal grain growth to increase. These changes in grain growth behaviour are explained by the effect of the change in step free energy with sintering atmosphere on the critical driving force necessary for rapid grain growth. The results show the possibility of fabricating $(K_{0.5}Na_{0.5})NbO_3$ at low temperature with various microstructures via proper control of sintering atmosphere.

태백산지역에 분포하는 화강암체 기원 견운모광상의 성인적 고찰 (Genetic Consideration of Sericite Deposits Derived from Granitic Rocks in the Taebaegsan Region)

  • 유장한;지세정
    • 한국광물학회지
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    • 제21권3호
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    • pp.239-246
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    • 2008
  • 강원도 영월 및 경북 봉화의 견운모광상은 화강암질 마그마의 알카리치환작용에 의한 광상으로 추정된다. 견운모광체는 캠브리아-트라이아기에 관입한 안주상의 우백질 화강암체 내에 배태되어 있으며, 이들 암주는 각기 시대미상의 페그마타이트질 미그마타이트와 선캠브리아기의 홍제사화강 암류를 관입하고 있다. 고생대 최하부층인 장산규암층은 열수작용 중에 그 방출을 막는 덮개역할을 하였으며, 견운모광상은 태백지향사 형성시에 생성된 함백향사의 남단 및 남동단에 각기 위치한다. 우백질 화강암류는 전기석을 가지는 페마타이트를 흔히 포함하며, 대체적으로 K 및 Na-장석류가 풍부하며, 광체는 암체의 상부 및 가장자리로 가면서 흔히 확인되며, 고품위광체는 거의 순수한 견운모 단일광물로 구성되는 초그라이젠화를 나타내기도 한다. 화학분석에 의하면, $Na_{2}O$$K_{2}O$함량이 $2.00\sim7.03wt%$로서 그라이젠화가 뚜렷하지만 CaO는 $0.05\sim4.51wt%$로서 알비타이트화는 미약하다. 영월 지역은 견운모와 함께 납석이 포함되므로 대현지역에 비하여 열수의 온도 등이 더 높았음을 암시한다. 태백산지역에는 그라이젠형광상으로 석석이 산출되었었고, 광상형성에 유리한 탄산염암의 분포가 넓으므로 중석, 휘수연 등의 감속원소와 함께 Be, Nb, Li 및 희토류원소류 등의 산출이 기대되며 이들에 대한 연구가 기대된다.