• 대한화학회지
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• 제37권12호
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• pp.987-994
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• 1993

유발효과와 공명효과는 케톤의 카르보닐기의 신축진동수를 결정하는데 중요한 역할을 하며 용액에서 수소결합, 유전효과 그리고 입체효과는 모두 케톤의 카르보닐 신축진동수, $ν_{C=O}$를 결정하는 인자이다. νC=O는 아세톤의 메틸기가 페닐기로 하나씩 치환될 때마다 약 27 $cm^{-1}$ 장파장 이동하였다. 케톤의$ν_{C=O}$진동수는 용매에 따라 다른 변화를 보이며 수용액에서 케톤의 부피비가 증가함에 따라 $ν_{C=O}$도 증가하였다. 케톤의 일정농도에서 $ν_{C=O}$ 진동수는 $(CH_3)_2SO/CCl_4$ 과 $CHCl_3/CCl_4$ 혼합 용매의 몰 비율 변화에 따라 연속적으로 이동하며 이로써 $ν_{C=O}$가 $(CH_3)_2SO$ 또는 $CCl_4$, $CHCl_3$ 또는 $CCl_4$의 농도 변화에 모두 영향을 받는다는 것을 알 수 있었다.

• 마이크로전자및패키징학회지
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• 제7권2호
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• pp.29-36
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• 2000

후막 페이스트용 glass frit의 내산성에 영향을 미치는 프릿트 제조방법 및 첨가제의 영향을 연구하였다. 프릿트 제조 방법에 따른 내산성을 관찰하기 위하여 $PbO-SiO_2-B_2O_3$기본 조성을 습식 및 건식 등의 흔합 방법 및 용융 횟수를 변수로 연구하였고, 첨가제에 의한 내산성 연구를 위하여 첨가제로 $ZrO_2$, $Al_2O_3$, $TiO_2$등을 0-l0wt% 첨가하여 첨가제에 따른 내산성 변화를 관찰하였다.

• 한국세라믹학회지
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• 제35권3호
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• pp.287-293
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• 1998

The effects of B2O3 addition on the sintering behavior and th microwave dielectric properties of $(Mg_{0.93}Ca_{0.07})TiO_3$ ceramics were investigated. By addition of $B_2O_3$, increases the density of the ceramics increases and grain growth enhances, It was densified to over 94% of $(Mg_{0.93}Ca_{0.07})TiO_3$ theoretical density by the addition of 0.15-1.0wt% B2O3 and stable microwave dielectric properties observed by the addition of 0.2-0.4wt% $B_2O_3.\;(Mg_{0.93}Ca_{0.07})TiO_3$ ceramics sintered at $1200^{\circ}C$ exhibits maximum dielectric constants of 24-25 quality factor($Q{\times}f$) of more than 70000 and temperature coefficient of resonant frequency of $0\;ppm/^{\circ}C$ by adding of 0.15-0.4wt% $B_2O_3$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1989년도 춘계학술대회 논문집
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• pp.93-96
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• 1989

NTC thermistor was prepared by adding TiO$_2$and MnO$_2$on Fe$_2$O$_3$and the effects of additions were investigated. And the effects of compating pressure, sintering temperature, and sintering time were also experimented. Fe$_2$O$_3$is insulator in stoichiometric state and will be semiconductor by introducing Ti$^{+4}$, Sn$^{+4}$. These semiconducting material will show large negative temperature coeffecients and can be used as NTC thermistor.tor.

• 대한전기학회논문지
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• 제34권5호
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• pp.186-192
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• 1985

Co2O3 additive effects on the electrical properties in ZnO varistor are investigated. As the Co Cations being substituted and ionized normally to a divalent state for Zn in the lattice site increase, the leakage current in the prebreakdown region decreases and the so-called

• 한국결정학회지
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• 제11권3호
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• pp.167-172
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• 2000

CaTiO₃:Pr phosphor thin films were prepared on Si(100), ZnO/glass, Corning glass and ITO/glass by rf magnetron reactive sputtering. The effects of deposition parameters such as oxygen partial pressure, substrate temperature, and annealing conditions on crystallinity and compositional variation of the films were investigated. PL spectra of CaTiO₃:Pr phosphor thin films exhibited red regime peaking at 613 nm and enhanced PL intensity was observed for the film annealed in vacuum atmosphere as compared to the deposit annealed in N₂ environment.

• 한국세라믹학회지
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• 제30권2호
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• pp.101-106
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• 1993

Effects of CaO on microwave dielectric properties of (Ba, Pb)O-Nd2O3-TiO2 ceramic ystem were investigated. As the content of CaO increases, the sintered bulk density decreases due to the decrease of sinterability. However, with increasing the sintering tmperature, the relative dielectric constants increases. This has been attributed on the formation of the 2nd phase inclusion, TiO2(rutile). The Q values increase due to the compensation effect of Ca ions up to 1 wt%, and then decrease due to the interfacial relaxation effects. The temperature coefficient of resonance frequency increases to a positive direction with increasing the amounts of CaO.

• 공업화학
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• 제22권1호
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• pp.26-30
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• 2011

염료 감응형 태양전지의 에너지 전환 효율을 향상시키고자 $TiO_2$에 $WO_3$을 첨가하여 광전극을 제조하고 그 전기화학적 특성 평가를 하였다. 또한 $WO_3$가 첨가된 $TiO_2$를 회쇄함으로써 회쇄 효과가 전지효율에 미치는 영향을 고찰하였다. I-V 곡선을 통하여 측정된 염료 감응형 태양전지의 효율은 $WO_3$ 첨가 및 회쇄 효과에 의하여 2.8에서 6.0%로 크게 증가하였다. 이와 같은 결과는 $TiO_2$의 전도대에서 전달되는 전자가 염료 및 전해질과 재결합되기 전에 $TiO_2$의 전도대보다 낮은 $WO_3$의 전도대를 통해 전달되기 때문에 전체 전류의 양이 증가되어 효율이 증가한 것으로 여겨진다. 또한, 임피던스 결과로부터 $TiO_2$/염료/전해질 계면의 저항 값이 감소하는 것을 확인하였다.

• 한국세라믹학회지
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• 제27권6호
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• pp.799-807
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• 1990

In this study, effects of oxide additives on mechanical properties and microstructure of A1N and A1N polytype ceramics were investigated. Fine A1N powder was synthesized by nitriding alumiuim hydroxide prepared from Al-isopropoxide, at 1350$^{\circ}C$ for 10h in N2 atmosphere. By adding 3w/o Y2O3, 0.56w/o CaO, and 10w/o SiO2 to AlN powder, AlN and AlN polytype ceramics were prepared by hot-pressing under the pressure of 30 MPa at 1800$^{\circ}C$ for 1h. AlN ceramics with no additives formed considerable amount of AlON phase, while AlN ceramics doped with Y2O3 or CaO decreased AlON phase and formed Y-Al or Ca-Al oxide compound. AlN＋10w/o SiO2(＋3w/o Y2O3) composition produced AlON and AlN polytype compound having 21R as a major phase. Room temperature flexural strength of AlN ceramics with no additive was 246MPa, and room temperature flexural strength and critical temperature difference by thermal shock(ΔTc) of AlN ceramics dooped with Y2O3 or CaO were 532MPa/340$^{\circ}C$ and 423MPa/300$^{\circ}C$, respectively. Y2O3 and CaO used as sintering agent played roles of densification and oxygen removal of AlN ceramics, and affected grain growth/grain morphologies of AlN ceramics.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1997년도 Proceedings of the 12th KACG Technical Meeting and the 4th Korea-Japan EMGS (Electronic Materials Growth Symposium)
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• pp.139-143
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• 1997

The doping effects of Mg and/or Fe ions on congruent LiNbO$_3$ single crystal growth were studied in order to clarify the roles of MgO in Fe doped LiNbO$_3$ single crystals. The effective distribution coefficienct of Fe was found decreased drastically from 0.85 to 0.5 by the addition of MgO into the LiNbO$_3$ melt. M ssbauer spectra revealed that the addition of MgO reduces the occurrence of Fe2+ ions during growth in air. Therefore, it is likely that there would be two important roles of MgO in Fe doped LiNbO$_3$. One is to suppress the incorporation of all Fe ions, and the other is to reduce the concentration of Fe2+ ions among the total Fe ions.