• 한국광학회:학술대회논문집
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• 한국광학회 1989년도 제4회 파동 및 레이저 학술발표회 4th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.222-224
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• 1989

A new fabrication method of proton-diffused LiNbO3 channel waveguides with self-aligned SiO2-Cladding structures are reported, which provides easy control of mode pattern shapes and sizes.

• 한국재료학회지
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• 제11권6호
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• pp.498-501
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• 2001

0.9Pb($Mg_{1/3}Nb_{2/3}$)$O_3$-0.1Pb$TiO_3$계 완화형 강유전체에서 MnO$_2$ 첨가가 압전물성에 미치는 영향을 강유전성이 우세한 온도영역인 -40~3$0^{\circ}C$의 온도범위에 걸쳐 조사하였다. MnO$_2$ 첨가에 의한 효과를 유전특성, 압전특성, 전계유기 변형특성 등의 영역에서 고찰하였다 MnO$_2$ 첨가량이 증가할수록 유전성 및 압전성은 hard piezoelectric의 경향을 나타내었다. 이러한 실험적 고찰로부터 첨가된 Mn은 강유전 도메인 분역을 고정하는 역할을 하는 것으로 제안되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.439-442
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• 2004

The effects of sintering additives on the low-temperature sintering and microwave dielectric properties of $Mg_4Nb_2O_9$ dielectric ceramics were studied. When $3{\sim}20wt%$ of $0.242Bi_2O_3-0.758V_2O_5$ was added, the sintering temperature decreased from $1100{\sim}1300^{\circ}C$ to $950^{\circ}C$ and high density was obtained. When $Mg_4Nb_2O_9$ was sintered at $950^{\circ}C$ with 10wt% of sintering additive, the microwave dielectric properties of $Q{\times}f_0\;=\;80.035GHz,\;\epsilon_r\;=\;13.3\;and\;\tau_f\;=\;-12.9\;ppm/^{\circ}C$ were obtained.

• 한국세라믹학회지
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• 제26권2호
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• pp.249-257
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• 1989

Dielectric properties and the stability of the perovskite phase in the Pb(Mg1/3Nb2/3)O3 system have been investigated as a function of amount of BaTiO3 and firing temperature. In the specimens fired at 120$0^{\circ}C$, the pyrochlore phase was eliminated by the addition of 10-15m/o BaTiO3 and also the dielectric constant increased. However, the dielectric constant decreased with further addition of BaTiO3 even though no pyrochlore phase was found to be present. The reducing tendency of the pyrochlore phase decreased with lowering the firing temperature in the system of Pb(Mg1/3Nb2/3)O3 with BaTiO3. Dielectric properties in PMN ceramics were affected by the character of the BaTiO3 rather than the pyrochlore phase.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.172-173
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• 2008

In this study, $0.95(K_{0.5}Na_{0.5})NbO_3$-0.05Li$(Sb_{0.8}Nb_{0.2})O_3$ + $Ag_2O$ + x wt% $MnO_2$ were investigated as a function of the amount of $MnO_2$ addition in order to improve dielectric and piezoelectric properties of Lead-free piezoelectric ceramics. With increasing the amount of $MnO_2$ addition, density and electromechanical coupling factor $(k_p)$ increased up to 0.3wt.% $MnO_2$ and decreased above 0.3wt.% $MnO_2$. At the sintering temperature of 1020 $^{\circ}C$, Electromechanical coupling factor $(k_p)$, density, dielectric constant $({\varepsilon}r)$ and mechanical quality factor $(Q_m)$ of composition ceramics with 0.4wt% $Ag_2O$ addition showed the optimal value of 0.431, 4.33 g/$cm^3$, 820 and 119, respectively.

• 한국재료학회지
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• 제5권8호
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• pp.1026-1034
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• 1995

저손실 망간징크 페라이트에서 CaO-SiO$_2$첨가는 입계에 높은 전기저항층을 형성시켜 와류에 의한 손실을 감소시키는 것으로 알려져 있다. 본 실험에서는 Nb$_2$O$_{5}$ 를 제 3의 첨가제로 사용하여 저손실 망간징크 페라이트에서의 전자기적 물성변화를 관찰하였다. Nb$_2$O$_{5}$ 300ppm 이상 첨가시 부분적인 과대입자 성장이 관찰되었으며, 200ppm 첨가시 CaO-SiO$_2$만 첨가한 시편에 비하여 밀도가 증가하였다. Nb$_2$O$_{5}$ 첨가시에는 100ppm 이하의 SiO$_2$첨가에서 우수한 전력손실 특성이 나타났으며, 고온 소결시 Nb$_2$O$_{5}$-CaO를 첨가한 시편에서 낮은 전력손실을 나타내었다.

• 한국세라믹학회지
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• 제34권9호
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• pp.921-926
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• 1997

Two NbCx-C1-x/Y2O3/Ti sputter-coated Al2O3 substrates (L 5.5 cm$\times$W 0.5 cm) were diffusion bonded together using hot press method at 95$0^{\circ}C$ for 3 hours under 1 MPa of applied pressure. 4 points bending tests were used to evaluate the mechanical performance of these precracked laminate beams. Two types of mechanical responses were observed: crack penetration through the interface for x=0.75, 1 and crack deflection into an interface for x=0.25, 0.5. The Al2O3/NbCx-C1-x/Y2O3/Ti system suggested here has been proves to be effective for the thermokinetical stability and tailorability of the interfaces of Al2O3/Ti composites at 95$0^{\circ}C$.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.333-336
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• 2005

The reduction behavior of $Nb_2O_5$ in aluminum containing self-reducing briquettes(SRNB) was investigated. The time required for slag/metal equilibrium was estimated as about 20 minutes from the addition of SRNB on to the surface of molten steel. The maximum yield of Nb was expected with the slag composition of $60\%CaO-40\%Al_2O_3$. When $CaCO_3$ was used as a flux, the oxidation loss of Al by $CO_2$ should be compensated, and the chemical equivalent ratio of Al to $Nb_2O_5$ of about 1.43 was required to maximize the yield of Nb.

• 한국전기전자재료학회논문지
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• 제17권7호
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• pp.718-723
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• 2004

Crystal structure of $(Ba-{1-x}La_x)[Mg_\frac{1+x}{3}}Nb_\frac{{2-x}{3}}]O_3$ (BLMN) ceramics with 0\leq1x \geq was investigated using synchrotron X-ray powder diffraction (XRD) and high reso(B $a_{l-x}$L $a_{x}$)[M $g_{(1+x)}$3/N $b_{(2-x)/3}$］ $O_3$lution transmission electron microscopy (HRTEM). When the La content, x, is above 0.1, the 1:2 ordered hexagonal structure found in Ba($Mg_\frac{1}{3}Nb_\frac{2}{3}})O_3$(BMN) was transformed into 1:1 ordered cubic structure. The 1:1 ordered cubic structure was maintained up to x=0.7. When x exceeded 0.7, however, BLMN was transformed into 1:1 ordered structure which has cation displacement and in-phase and anti-phase tilt of octahedra.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1427-1429
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• 2003

The $ZnNb_2O_6$ ceramics with 3wt% CuO were prepared by the conventional mixed oxide method. The ceramics were sintered at the temperature of $1000^{\circ}C{\sim}1075^{\circ}C$ for 3hr. in air. The structural properties were investigated with sintering temperature by XRD and SEM. Also, the microwave dielectric properties were investigated with sintering temperature. Increasing the sintering temperature, the peak of second phase($Cu_3Nb_2O_8$) was increased. In the case of $ZnNb_2O_6$+CuO(3wt%) ceramics sintered at $1025^{\circ}C$ for 3hr, the dielectric constant, quality factor were 21.73, 19.276, respectively.