• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.141-141
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• 2009

흑색 3가크롬용액을 최적의 전착조건을 찾기 위해서 pH와 온도의 변화에 따란 Hull-cell test, 두께측정, 분극실험을 실시하였다. 온도가 올라갈수록, pH가 낮을수록 도금층의 두께가 두꺼워졌으나, 온도 $40^{\circ}C$, pH 3.4-3.8일때 균일한 도금층을 얻을 수 있었다.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.10a
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• pp.271-275
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• 2005

Pine bark, chinese cabbage, crap shell which are used for removing metal ions from aqueous solutions. The removal of metal ions from aqueous solution by adsorption and ion exchange on bio residues was studied. Biosorption of $Cu^{2+},\;Ni^{2+},\;Pb^{2+}$ were compared. Adsorption ability different for the factors [adsorption time, adsorbent weight, initial concentration] and all experiments pH variation were investigated. It was shown that chinese cabbage has higher metal removal ability than other materials The pH variation of metal solution were investigated according to the influences of the initial concentration and weight adsorbents.

• Korean journal of food and cookery science
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• v.8 no.1
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• pp.27-30
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• 1992

The changes on the pH and acidity of kimchi with the addition of different amounts of onion were inverstigated during fermentation at $14^{\circ}C$ and $21^{\circ}C$ for 20 days. As the fermentation period increases, the pH of kimchi contained onion was higher than that of control kimchi, and tokal, volatile and non-volatile acidity of kimchi contatined onion were lower than those of control kimchi, at $14^{\circ}C$ and $21^{\circ}C$.

• Korean journal of food and cookery science
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• v.18 no.6
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• pp.698-703
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• 2002

The objective of this study was to determine the effects of wine and different meat bones added in brown sauce. Four kinds of brown sauce were prepared to find the changes of physiochemical characteristics, such as pH, $\alpha$-amylase activity, color, viscosity and microorganisms in brown sauce during storage at 4$\^{C}$. The pH of 4 kinds of brown sauce ranged from 5.0 to 5.6, and these pH ranges were stable during storage period. The activity of $\alpha$-amylase was the highest in the brown sauce made with wine and some of chicken bones and the sauces stored for 2 ∼ 6 days. The brown sauce made with wine and some of chicken bones had 35.5% of reducing sugar, which was the highest among 4 kinds of brown sauce, and had the darkest color. Also the brown sauce with wine and some of chicken bones shooed low values of L, a, b after storage and the lowest viscosity among 4 kinds of brown sauce. But they all tended to have higher viscosity during storage, especially two days after. The sauce made with wine and some of chicken bones showed the least change of viscosity and the addition of wine in the sauce appeared to inhibit the microbial growth.

• Restorative Dentistry and Endodontics
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• v.35 no.2
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• pp.96-105
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• 2010

The purpose of this study is to observe and compare the remineralization tendencies of artificial enamel caries lesion by remineralization solutions of different degree of saturations at pH 5.5, using a polarizing microscope and computer programs (Photoshop, Image pro plus, Scion Image, Excel). For this study, 48 sound permanent teeth with no signs of demineralization, cracks, or dental restorations were used. The specimens were immersed in lactic acid demineralization solution for 2 days in order to produce artificial dental caries that consist of surface and subsurface lesions. Each of 9 or 10 specimens was immersed in pH 5.5 lactic acid buffering remineralization solution of four different degrees of saturation (0.507, 0.394, 0.301, and 0.251) for 12 days. After the demineralization and remineralization, images were taken by a polarizing microscope (${\times}100$). The results were obtained by observing images of the specimens, and using computer programs, the density of caries lesions were est mated. While the group with the lowest degree of saturation (0.251) showed total remineralization feature from the surface to the subsurface of the lesion, the group with the highest degree of saturation (0.507) showed demineralization mainly on the surface of the lesion at the constant organic acid concentration 0.01 M and pH 5.5.

• Proceedings of the Membrane Society of Korea Conference
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• 2001.11a
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• pp.42-45
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• 2001

• The Korean Journal of Food And Nutrition
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• v.30 no.2
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• pp.388-394
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• 2017

This study investigated the stability of ethanolic extract from fermented Cirsium setidens Nakai (FCSN) in order to develop functional materials during different storage conditions. We evaluated pectolinarin and pectolinarigenin contents, total phenol content and antioxidant activity (DPPH radical scavenging activity and FRAP assay) of ethanolic extract from FCSN obtained by bioconverison at various temperatures (4, 25 and $50^{\circ}C$) and pHs (4.0, 7.0 and 10.0). Our results show that the pectolinarin, pectolinarigenin, and total phenol contents in ethanolic extract from FCSN were decreased during the storage periods. Moreover, the DPPH radical scavenging activity did not significantly change at $4^{\circ}C$ and $25^{\circ}C$. Pectolinarin and pectolinarigenin contents, total phenol content and DPPH radical scavenging activity of ethanolic extract from FCSN at acidic pH (pH 4.0) and neutral pH (pH 7.0) were higher than those at the alkaline pH range. These results indicate that the optimum storage condition of the ethanolic extract from FCSN was $4^{\circ}C$ and pH 4.0~7.0 range.

• Clean Technology
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• v.10 no.1
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• pp.47-51
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• 2004

현재 반도체 공정에서 사용되는 세정기술은 대부분이 1970년대 개발된 RCA 세정법인 과산화수소를 근간으로 하는 습식 세정으로, 표면의 입자를 제거하기 위한 SC-1 세정액은 강력한 산화제인 과산화수소에 의한 표면과 입자의 산화와 암모니아에 의한 표면의 에칭이 동시에 일어나 입자를 표면으로부터 분리시킨다. 금속 불순물을 제거하기 위한 SC-2 세정액은 염산과 과산화수소 혼합액을 사용하며 금속 불순물을 용해시켜 알칼리나 금속 이온을 형성하거나 용해 가능한 화합물을 형성시켜 제거한다. 또한 황산과 과산화수소를 혼합한 Piranha 세정액은 효과적인 유기물 제거제로서 웨이퍼에 오염된 유기물을 용해 가능한 화합물로 만들거나 과산화수소에 의해 형성되는 산화막내에 오염물을 포함시켜 불산 용액으로 산화막을 제거할 때 함께 제거된다. 최근 금속과 산화막을 동시에 제거하기 위해 희석시킨 불산에 과산화수소를 첨가한 세정공정이 사용되고 있으며 불산에 의해 표면의 산화막이 제거될 때 산화막내에 포함된 금속 불순물을 동시에 제거시킬 수 있다. 그러나 이와 같이 습식세정액 내에 공통적으로 포함되어 있는 과산화수소의 분해는 그만큼 가속화되어 사용되는 화학 약품의 양이 그만큼 증가하게 되고 조작하기 어려운 단점도 있다. 이를 해결하기 위해 환경친화적인 관점으로 화학약품의 사용을 최소화하는 등 RCA세정을 보완하는 연구가 계속 진행되고 있다. 본 연구에서는 RCA세정법을 환경적으로 대체할 수 있는 세정에 사용되는 전리수의 pH변화에 따른 전리수 분석을 하였다. 전리수의 제조를 위하여 전해질로는 NH4CI (HCI:H2O:NH4OH=1:1:1)를 사용하였다. pH 11 이상, ORP -700mV~-850mV인 환원수와 pH 3 이하, ORP 1000mV~1200mV인 산화수를 제조하였으며, 초순수를 첨가하여 pH 7.2와 ORP 351.1mV상태까지 조절하였다. 이렇게 만들어진 산화수와 환원수를 시간 변화와 pH 변화에 따라 Clean Room 안에서 FT-IR과 접촉각 측정기로 실험하였다. FT-IR분석에서 산화수는 pH가 높아질수록, 환원수는 낮아질수록 흡수율이 낮아졌다. 접촉각 실험에서는 산화수의 pH가 높아질수록 환원수의 pH가 낮아질수록 접촉각이 커짐을 확인하였다. 결론적으로 전리수를 이용하여 세정을 하면, 접촉성을 조절할 수 있어 반도체 세정을 가능하게 할 수 있으며, 환경친화적인 결과를 도출할 것으로 전망된다.

• Journal of Food Hygiene and Safety
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• v.9 no.4
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• pp.185-189
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• 1994

This study was to investigate time-dependent degradation process under various pH condition for organophosphorus(org-p) insecticides, namely Demeton-s-methyl, diazinon, Parathion, Phenthoate, and EPN in several waters. They were analysed by GC-FTD according to standard methods for the examination of water and wastewater. In pH=4, diazinon showed disappearance after 14 days in chromatogram. In pH=11, org-p insecticides were almost degradable after 7 days. In this condition, effect of pH on degradation process was greater than of light. In pH=7, org-p insecticides persisted residues after 112 days except Demeton-s-methyl. In BOD5 120, 250 ppm and domestic water, org-p insecticides showed also rapid degradation process.

• Applied Biological Chemistry
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• v.41 no.7
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• pp.545-549
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• 1998

This study was carried out to improve the storage stability of export peeled-chestnuts using electrolyzed acid-water, because ice-cold tap water generally used to store export peeled-chestnuts grew turbid during the cold chain, decreasing the quality. The changes of pH and turbidity in the electrolyzed water used for storing peeled-chestnuts were investigated. The pH value rapidly changed when stored at $30^{\circ}C$, whereas it very slowly changed at $4^{\circ}C$. This was especially evident by the change in pH from 2.5 to 3.4 of the electrolyzed acid-water after 8 days. In the case of turbidity, closely correlated with the pH change, the electrolyzed water used for storing peeled-chestnuts was very turbid when stored at $30^{\circ}C$, but it was not even until 14 days at $4^{\circ}C$, as evident by the absorbance $(OD_{660})$ of electrolyzed acid-water at pH 2.5 and $4^{\circ}C$ being only 0.01 after 14 days and 0.11 after 35 days. Sensory evaluation, tested by expert panel, of the chestnuts stored in electrolyzed water was not significantly different compared to the control.