• Korean Chemical Engineering Research
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• 제48권5호
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• pp.627-631
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• 2010

질산 알루미늄과 암모니아 용액을 출발물질로 하고 또한 금속 불화물을 첨가제로 사용하여 $\alpha$-알루미나 입자를 침전법으로 제조하였다. 이 때 제조과정에서 사용된 용매의 영향과 $AlF_3$, $CaF_2$, $MnF_2$ 등의 3 가지 금속 불화물 첨가제가 $\alpha$-알루미나로의 상전이 온도, 입자 크기 및 형태 등에 미치는 영향에 대해 조사하였다. $\alpha$-알루미나 제조시 사용된 용매는 상전이 온도에는 큰 영향을 미치지 않는 반면 입자 크기에 영향을 미쳤다. 첨가제 조성에 따라 $\alpha$-알루미나 상전이 온도가 차이가 났으나($AlF_3(800^{\circ}C)$ < $MnF_2(900^{\circ}C)$ < $CaF_2(950^{\circ}C)$), 첨가제를 사용하지 않은 경우($1,100^{\circ}C$)보다는 모두 상전이 온도가 낮음을 알 수 있었다. 3 가지 첨가제를 사용한 경우 모두 판상의 $\alpha$-알루미나 입자들이 얻어졌으나, 그 중 $MnF_2$를 첨가한 경우에 가장 작은 크기의 $\alpha$-알루미나 입자들이 생성되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.375-378
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• 2002

We investigated the reduction of etching damage by additive O$_2$ in etching gas and recovery of etching damage by O$_2$ annealing. The PZT thin films were etched using additive Ar or O$_2$ into Cl$_2$/CF$_4$ gas mixing ratio of 8/2. In order to recover ferroelectric properties of PZT thin films after etching, the etched PZT thin films were annealed at 600 C in O$_2$ atmosphere for 10 min. The remanent polarization is decreased seriously and fatigue is accelerated in the PZT sample etched in Ar/(C1$_2$+CF$_4$) plasma, whereas these characteristics are improved in O$_2$/(Cl$_2$/CF$_4$). From x-ray photoelectron spectroscopy (XPS) analysis, the intensities of Pb-O, Zr-O and Ti-O peaks are changed and the etch byproducts such as metal chloride and metal fluoride are reduced by O$_2$ annealing. From electron probe micro analyzer (EPMA) and auger electron spectroscopy(AES), O$_2$ vacancy is observed after etching. In x-ray diffraction (XRD), the structure damage in the additive O$_2$ into C1$_2$/CF$_4$ is reduced and the improvement of ferroelectric behavioral annealed sample is consistent with the increase of the (100) and (200) PZT peaks.

• Journal of Microbiology and Biotechnology
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• 제33권2호
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• pp.195-202
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• 2023

Protease is a widely used enzyme particularly in the detergent industry. In this research, we aimed to isolate alkaline protease-producing bacteria for characterization as a laundry detergent additive. The screening of alkaline protease production was investigated on basal medium agar plus 1% skim milk at pH 11, with incubation at 30℃. The highest alkaline protease-producing bacterium was 6BS15-4 strain, identified as Bacillus gibsonii by 16S rRNA gene sequencing. While the optimum pH was 12.0, the strain was stable at pH range 7.0-12.0 when incubated at 45℃ for 60 min. The alkaline protease produced by B. gibsonii 6BS15-4 using dairy effluent was characterized. The optimum temperature was 60℃ and the enzyme was stable at 55℃ when incubated at pH 11.0 for 60 min. Metal ions K⁺, Mg²⁺, Cu²⁺, Na⁺, and Zn²⁺ exhibited a slightly stimulatory effect on enzyme activity. The enzyme retained over 80% of its activity in the presence of Ca²⁺, Ba²⁺, and Mn²⁺. Thiol reagent and ethylenediaminetetraacetic acid did not inhibit the enzyme activity, whereas phenylmethylsulfonyl fluoride significantly inhibited the protease activity. The alkaline protease from B. gibsonii 6BS15-4 demonstrated efficiency in blood stain removal and could therefore be used as a detergent additive, with potential for various other industrial applications.

• 마이크로전자및패키징학회지
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• 제26권3호
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• pp.59-62
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• 2019

본 논문은 용액공정용 불소 도핑된 인듈 갈륨 징크 산화물 반도체를 연구하였으며, 박막 트랜지스터 적용 가능성을 확인하였다. 용액형 산화물 반도체를 형성하기 위해, 금속염 전구체 기반 용액을 제조하였으며, 추가적인 불소 도핑을 유도하기 위해 화학적 첨가제로서 암모늄 플로라이드를 이용하였다. 열처리 온도 및 불소 도핑양에 따른 전기적 물성을 고찰함으로서, 300도 저온 열처리를 통해 제조된 산화물 반도체층의 전기적 특성을 향상시켰다. 20 mol% 불소를 도핑하는 경우, $1.2cm^2/V{\cdot}sec$의 이동도 및 $7{\times}10^6$의 점멸비 특성이 발현 가능함을 확인하였다.