• 센서학회지
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• 제6권3호
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• pp.200-206
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• 1997

열산화시킨 실리콘 웨이퍼 위에 저압화학기상성장법으로 $SiCl_{2}H_{2}$, $NH_{3}$ 및 $N_{2}O$ 기체를 사용하여 실리콘 옥시나이트라이드($Si_{x}O_{y}N_{z}$) 층을 제작하였다. 세 가지의 다른 조성이 기체 유속비($NH_{3}/N_{2}O$)를 각기 0.2, 0.5 및 2로 변화시키고 $SiCl_{2}H_{2}$의 기체 유속은 고정시킴으로써 얻어졌다. 엘립소메트리와 HFCV(High Frequency Capacitance-Voltage) 측정법을 채택하여 굴절율, 유전율 및 조성의 차이를 각각 조사했다. 실리콘 옥시나이트라이드는 내부에 포함된 실리콘 나이트라이드 성분량에 관계없이 용액 중에서 순수한 실리콘 나이트라이드와 유사한 안정성을 보유했다. 실리콘 옥시나이트라이드 층 알칼리이온 감지성의 크기 순서는 실리콘 나이트라이드 성분량에 영향을 받았다. 보다 나은 알칼리이온 감지성이 실리콘 옥시나이트라이드의 벌크 내에 있는 실리콘 디옥시드의 성분량을 증가시킴으로써 얻어졌다.

• Transactions on Electrical and Electronic Materials
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• 제9권6호
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• pp.231-236
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• 2008

B, P, and Cs ions were implanted with various parameters into silicon nitride layers prepared by LPCVD. In order to get the maximum impurity concentration at the silicon nitride surface, a high temperature oxide (HTO) buffer layers was deposited prior to the implantation. Alkali ion and pH sensing properties of the layers were investigated with an electrolyte-insulator-silicon (EIS) structure using high frequency capacitance-voltage (HF-CV) measurements. The ion sensing properties of implanted silicon nitrides were compared to those of as-deposited silicon nitride. Band Cs co-implanted silicon nitrides showed a pronounced difference in pH and alkali ion sensing properties compared to those of as-deposited silicon nitride. B or P implanted silicon nitrides in contrast showed similar ion sensitivities like those of as-deposited silicon nitride.

• 한국식품과학회지
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• 제53권2호
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• pp.121-125
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• 2021

Very low methoxyl pectin (VLMP) has different physical and rheological properties compared to high and low methoxyl pectins (HMP and LMP). In this study, we produced LMP and VLMP by alkaline de-esterification, and investigated the structural and textural properties. Apple peel pectin was kept at pH 12 using 5.0 M NaOH solution for 3 and 24 h to produce LMP and VLMP, respectively. The molecular weight was decreased due to the removal of an esterified group in the pectin backbones by the alkali treatment, and the VLMP showed a higher calcium ion sensitivity which leads to the production of the gel with increased hardness. The result clearly showed that VLMP has the potential to improve the texture and stability in food products depending on their degree of esterification, and this result can be applied as a functional ingredient in food industrial area application to enhance the current commercial pectins.

• 한국토양환경학회지
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• 제1권2호
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• pp.43-50
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• 1996

The adsorption charateristics of lead(II) ions on Aspergillus niger and Rhizopus arrhizus were investigated. Adsorption amount of A. niger and R. arrhizus was about 95 mg/g and 25 mg/g, respectively. These biomass was approached to adsorption equilibrium within reaction time of 1hr because of their high reactivity. The uptake of lead ion by A. niger was less sensitivity than it by R. arrhizus on the inhibition effect of alkali metals and the decreasing ratio of uptake of lead ion of A. niger and R. arrhizus by inhibition effect of alkali metals was 37% and 50%, respectively. In pre-treatment on these biomass, NaOH treatment was contributed high adsorption capacity to these biomass. Then, adsorption amount of A. niger and R. allhizus was increased about 25 mg/g and 10 mg/g, respectively. In isotherm for the adsorption of lead ion based on Freundlich equation, 1/n value of A. niger and R. ar고izus was calculated the range of 0.28-0.56 and 0.44-0.67, respectively.

• 분석과학
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• 제6권3호
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• pp.247-254
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• 1993

스트론튬을 비롯한 알칼리 토금속의 전기화학적 분석의 적용은 수용액상에서 DME(Drop Mercury Electrod)에 대한 환원이 어렵기 때문에 그 연구가 많지 않다. 본 연구에서는 지금까지 UV-VIS 흡광광도법에서 스트론튬의 분석에 이용되어 온 o-Cresolphthaleoxon을 가지고 이들 사이의 착물형성에 따른 전자이동을 이용하여 전기화학적 분석에 적용시켰다. 이 때 지지전해질의 선택, Accumulation Potential 등 전기화학적 분석에 영향을 미치는 실험조건 등을 조사하여 정량범위를 결정짓고, 분석시 공존 이온의 영향을 조사하였다. UV-VIS 흡광광도법의 경우 $100{\mu}g/L$로 검출감도가 좋지 못하였으나, 전기화학적 방법을 이용할 경우 $5{\sim}30{\mu}g/L$ 범위까지의 정량이 가능하였다.

• 대한수의학회지
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• 제32권4호
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• pp.543-553
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• 1992

Properties of unitary ATP-sensitive $K^+$ channels were studied using planar lipid bilayer technique. Vesicles were prepared from bullfrog (Rana catesbeiana) skeletal muscle. ATP-sensitive $K^+$ (K (ATP)) channels were identified by their unitary conductance and sensitivity to ATP. In the symmetrical solution containing 200mM KCI, 10mM Hepes, 1mM EGTA and pH 7.2, single K (ATP) channels showed a linear current-voltage relations with slight inward rectification. Slope conductance at reversal potential was $60.1{\pm}0.43$ pS(n=3)). Micromolar ATP reversibly inhibited the channel activity when applied to the cytoplasmic side. In the range of -50~＋50 mV, the channel activity was not voltage-dependent, but the channel gating within a burst was more frequent at negative voltage range. Varying the concentrations of external/internal KCl(mM) to 40/200, 200/200, 200/100 and 200/40 shifted reversal potentials to $-30.8{\pm}2.9$(n=3), $-1.1{\pm}2.7$(n=3), 10.5 and 30.6(mV), respecrivety. These reversal potentials were close to the expected values by the Nernst equation, indicating nearly ideal selectivity for $K^+$ over $Cl^-$. Under bi-ionic conditions of 200mM external test ions and 200mM internal $K^+$, the reversal potentials for each test ion/K pair were measured. The measured reversal potentials were used for the calculation of the releative permeability of alkali cations to $K^+$ ions using the Goldman-Hodgkin-Katz equation. The permeability sequence of 5 cations relative to $K^+$ was $K^+$(1), $Rb^+$(0.49), $Cs^+$(0.27), $Na^+$(0.027) and $Li^+$(0.021). This sequence was recognized as Eisenman's selectivity sequence IV. In addition, modelling the permeation of $K^+$ ion through ATP-sensitive $K^+$ channel revealed that a 3-barrier 2-site multiple occupancy model can reasonably predict the observed current-voltage relations.