• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.214-216
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• 2006

In this study, in order to develop the composition ceramics for low loss and low temperature sintering multilayer piezoelectric actuator, PMN-PZN-PZT ceramics were fabricated using two stage calcination method and $Li_2CO_3$, $Bi_2O_3$ and CuO as sintering aids and their piezoelectric characteristics were investigated according to the 2nd calcination and sintering temperature. At the calcination temperature of $750^{\circ}C$ and sintering temperature of $930^{\circ}C$, density, electromechanical coupling factor ($k_p$), mechanical quality factor ($Q_m$), Dielectric constant (${\varepsilon}_r$) and piezoelectric constant ($d_{33}$) of specimen showed the optimum value of $7.94g/cm^2$ 0.581, 1554, 1555 and 356pC/N, respectively for multilayer piezoelectric actuator application.

• 한국전기전자재료학회논문지
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• 제21권3호
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• pp.217-221
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• 2008

In this study, We have been investigated the effect of calcination temperature and high-energy ball-milling of powder influences the $BaTiO_3$-based PTCR(Positive Temperature coefficient Resistance) characteristics and microstructure. The mixed powder was obtained from $BaCO_3$, $TiO_2$, $CeO_2$ ball-milled in attrition mill. The mixed powder was calcine from 1000 $^{\circ}C$ to 1200 $^{\circ}C$ in air and then it was sintered in reduction- re-oxidation atmosphere. As a result, The room-temperature electrical resistivity decreased and increased with increasing calcination temperature. specially, Attrition milled powder could have low room-temperature resistivity and high PTC jump order at 1100 $^{\circ}C$. attrition milling had lower room-temperature resistivity than ball milling. Particle size decreased by Attrition milling of powder influences in calcination temperature and room-temperature resistivity.

• 공업화학
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• 제33권1호
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• pp.64-70
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• 2022

본 연구에서는 NH₃-SCR에서 VWTi촉매의 저온 탈질효율 증진을 위해 Sb을 첨가하여 실험을 수행하였으며 Sb 첨가에 있어 다양한 소성온도(400~700 ℃)에서 제조하였다. NH₃-SCR 실험 결과 Sb 소성온도 500~600 ℃에 해당하는 VWSbTi(500)와 VWSbTi(600) 촉매가 300 ℃ 이하의 저온에서 가장 우수한 탈질성능을 나타냈으며, 소성온도에 따른 물리화학적 특성을 확인하고자 BET, XRD, Raman, XPS, H₂-TPR, NH₃-TPD 분석을 수행하였다. VWSbTi(500)와 VWSbTi(600)의 경우 W=O종의 생성에 따라 암모니아 산점이 증가하였으며 텅스텐의 전자밀도 증가에 따른 우수한 redox 특성으로 저온에서 우수한 활성을 나타내었다. 또한 VWSbTi(700)의 경우 V₂O₅ 결정구조가 형성되어 활성이 저하됨에 따라 Sb 첨가과정에 있어 최적의 소성온도를 확인하였다.

• 한국전기전자재료학회논문지
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• 제29권3호
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• pp.159-163
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• 2016

In this paper, in order to develop optimum composition ceramics with excellent piezoelectric properties, $(Na_{0.525}K_{0.443}Li_{0.037})(Nb_{0.823}Sb_{0.08}Ta_{0.037})O_3+0.3wt%Bi_2O_3+0.4wt%Fe_2O_3$ lead-free piezoelectric ceramics were synthesized by conventional soild-state method. The calcination temperature of columbite precursors were fabricated at temperature range from $950^{\circ}C$ to $1,150^{\circ}C$ and sintering aids with low melting point were added to densify these ceramics. Effect of calcination temperature on dielectric and piezoelectric properties of ceramics were investigated. the ceramics with B-site columbite precursors at temperature of $1,100^{\circ}C$ obtained the optimal values of $d_{33}=272$ [pC/N], $k_p=0.51$, $Q_m=102$, ${\varepsilon}_r=978$.

• 한국산학기술학회논문지
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• 제16권1호
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• pp.900-905
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• 2015

본 Mn-Cu-$TiO_2$ Civil 촉매를 이용하여 질소산화물을 제거하는 $NH_3$-SCR 공정에서 소성조건 및 산소농도에 대한 영향을 연구하였다. 소성된 촉매시료를 사용하여 $H_2$-TPR 시스템에서 반응온도에 따른 수소전환특성을 조사하였으며, 소성조건에 대한 비표면적변화도 측정하였다. 실험결과 적합한 소성온도는 약 $300^{\circ}C$이며, 소성온도가 $500^{\circ}C$이상일 경우 Mn, Cu 성분의 저온활성이 크게 감소함을 알 수 있었다. SCR반응에서 기상산소는 중요한 반응변수이며 반응에 적합한 농도는 약 8vol%이었다.

• 한국안전학회지
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• 제19권4호
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• pp.74-79
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• 2004

[ $CO_3O_4/{\gamma}-Al_2O_3$ ] catalysts were reported high activity on the low temperature CO oxidation. The effects of the calcination temperature, the loaded amount of cobalt and the oxygen concentration on the characteristics of CO oxidation have been investigated for a emergency escape mask cartridge. $Co(NO_3)_2\cdot6H_2O$ was used as cobalt precursor and the catalysts were prepared by incipient wetness impregnation. TGA shows that enough calcination is accomplished at $450^{\circ}C$ and cobalt phase is $Co_3O_4$ after calcination in the temperature range of $300\ ~500^{\circ}C$. The specific surface area and pore volume of catalysts are decreased with increasing of loaded amount of cobalt. And with the increase of loaded amount of cobalt and the oxygen concentration, the catalytic activity is increased.

• 신재생에너지
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• 제20권2호
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• pp.71-81
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• 2024

In this study, the electrochemical properties of garnet-structured all-solid-state battery electrolytes (Li_6.4La₃Zr_1.4Ta_0.6O₁₂, hereafter LLZTO) were assessed by altering the calcination temperature, while maintaining a consistent sintering duration. Among the various heat treatment conditions employed for sample fabrication, the '700_1100' condition, denoting a calcination temperature of 700℃ and a sintering temperature of 1100℃, resulted in the most exceptional ionic conductivity of 4.89 × 10^-4 S/cm and a relative density of 88.72% for the LLZTO material. This is attributed to the low calcination temperature of 700℃, leading to reduced grain size and enhanced cohesiveness, thus resulting in a higher sintered density. In addition, a microstructure similar to the typical sintering characteristics observed in Spark Plasma Sintering (SPS) methods was identified in the SEM analysis results under the '700_1100' condition. Consequently, the '700_1100' heat treatment condition was deemed to optimal choice for enhancing ionic conductivity.

• 대한화학회지
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• 제56권5호
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• pp.609-616
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• 2012

Ba-ferrite ($BaFe_{12}O_{19}$) nanoparticles were synthesized by chemical coprecipitation method in an aqueous solution. The particle size and the crystallization temperature of the Ba-ferrite nanoparticles were controlled varying the precipitation temperature. The precipitate that was prepared at $0^{\circ}C$ showed the crystal structure of Ba-ferrite in X-ray diffraction when it was calcined at the temperature above $580^{\circ}C$, whereas what was prepared at $50^{\circ}C$ showed the crystallinity when it was calcined at the temperature higher than about $700^{\circ}C$. The particle sizes of the synthesized Ba-ferrite were in a range of about 20-30 nm when it was prepared by being precipitated at $0^{\circ}C$ and calcined at $650^{\circ}C$. When the precipitation temperature increased, the particle size also increased even at the same calcination temperature. The magnetic properties of the Ba-ferrite nanoparticles were also controlled by the synthetic condition of precipitation and calcination temperature. The coercive force could be appreciably lowered without a loss of saturation magnetization when the Ba-ferrite nanoparticles were prepared by precipitation and calcination both at low temperatures.

• 한국세라믹학회지
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• 제27권8호
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• pp.971-978
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• 1990

The ifluence of transformability and stabilized effects in tetragonal phase on the isothermal phase transformation of Y-TZP at low temperature were investigated. The transformability of Y-TZP powders were gradually increased with calcination temeprature and reached maximum at critical temperature, but when the Y-TZP powders were calcined above critical temperature, transformability of Y-TZP were gradually decreased with increasing calcination temperature. It was concluded that maximum transformability was appeared because particle size effects decreased and constrain effects increased with calcined temperature. The isothermal phase transformation during aging at 25$0^{\circ}C$ only observed in Y-TZP stabilized by constrain effects and the amounts of transformation during aging at 25$0^{\circ}C$ only observed in Y-TZP stabilized by constrain effects and the amount of transformed monoclinic phase during aging decreased with increasing constrain effects. From these results, the mechanism of isothermal phase transformation and degradation behaviors at low temperature in Y-TZP was concluded that occurred by decreasing of constrain effects due to stress relaxation at grian boundary.

• 한국토양비료학회지
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• 제27권1호
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• pp.10-14
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• 1994

지효성 K비료는 KOH, KCl 등 속효성 K원료와 Fly ash중 난용성 K를 이용하였고 소성시 보조제로서 부연탄가루, $Mg(OH)_2$, $K_2CO_3$와 Borax를 혼합하여 제조하였다. 목표 K함량에 맞게 원료와 보조제 혼합비율이 결정되었으며 무연탄가루와 $Mg(OH)_2$의 적정 배합비율은 각각 12%, 3%이었으며 소성온도는 $850^{\circ}C$, 소성시간은 30분이 적정선으로 판명되었다. 시제품은 소성온도가 낮고 소성시간이 짧은 경우 시제품의 특성에 부적합하였다. 제조된 시제품의 K성분은 지효화되어 목표치에 부합되었다.