• Bulletin of the Korean Chemical Society
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• 제35권12호
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• pp.3595-3600
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• 2014

Monitoring of pH, especially under highly alkaline conditions, is necessary in various processes in the industrial, biotechnological, agricultural, and environmental fields. However, few pH indicators that can function at highly alkaline levels are available, and most of which are organic-based pH indicators. Several years ago, it was reported that gold nanoparticles prepared using trisodium citrate dihydrate were rapidly aggregated at pH values higher than ~12.7. A shift of surface plasmon resonance for such aggregated gold nanoparticles can be applied to pH indicators, allowing for the substitution of traditional organic-based pH indicators. The most important characteristic of pH indicators is the transition pH range. Herein, gold and silver nanoparticles are prepared using different reducing agents, and their transition pH ranges are examined. The results showed that all nanoparticles prepared in this study exhibit similar transition pH ranges spanning 11.9-13.0, regardless of the nanoparticle material, reducing agents, and concentration.

• 한국식품과학회지
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• 제30권3호
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• pp.557-561
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• 1998

본 연구에서는 산성(pH 2.0, 3.0), 중성(pH 7.0) 및 알칼리성(pH 10.0, 12.0)영역에서 각각 추출된 SPI들의 기능성을 상호비교하였다. pH 3.0에서 추출된 SPI의 단백질함량은 93.31%로 최고값을, pH 7.0에서 추출된 SPI의 단백질함량은 73.93%로 최소값을 나타내었다. pH 3.0에서 추출된 SPI의 추출수율은 0.36%로 최소값을, pH 12.0에서 추출된 SPI의 추출수율은 47.54%로 최고값을 나타내었다. SPI의 기능성(용해도, 수분흡수력, 유지흡수력, 기포형성력, 기포안정성, 유화형성력 및 겔형성력)은 대두단백질 추출시 추출용액의 pH에 의해 크게 좌우되었다. pH 2.0과 3.0에서 추출된 SPI의 용해도는 산성영역에서 크게 나타났고 pH 3.0과 7.0에서 추출된 SPI는 중성 영역에서 높은 용해도를 보였으나 pH 2.0, 3.0, 7.0, 10.0 및 12.0에서 추출된 SPI는 모두 알칼리성 영역(pH 9.0-10.0)에서 높은 용해도를 나타내었다. pH 2.0과 pH 12.0에서 추출된 SPI의 수분흡수력, 유지흡수력, 기포형성력 및 기포안정성은 다른 pH에서 추출된 SPI보다 크게 나타났으나 유화력의 경우 추출용액의 pH가 증가할수록 유화력이 증가하였다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2018년도 춘계학술대회 논문집
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• pp.33.1-33.1
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• 2018

pH is expressed mathematically as $pH=-{\log}[H^+]$, is a measure of the hydrogen ion concentration, [$H^+$] to specify the acidity or basicity of an aqueous solution. The pH scale usually ranges from 0 to 14. Every aqueous solution can be measured to determine its pH value. The pH values below 7.0 express the acidity, above 7.0 are alkalinity and pH 7.0 is a neutral solution. The solution pH can be determined by indicator or by measurement using pH sensor, which measuring the voltage generated between a glass electrode and a reference electrode according to the Nernst Equation. The pH value of solutions depends on the temperature and the activity of contained ions. In nickel electroless plating process, the controlled pH value in some limited ranges are extremely important to achieve optimal deposition rate, phosphorus content as well as solution stability. Basically, nickel electroless plating solution contains of $Ni^{2+}ions$, reducing agent, buffer and complexing agents. The plating processes are normally carried out at $82-92^{\circ}C$. However, the change of its pH values with temperatures does not follow any rule. Thus, the purpose of study is to understand the relationship between pH and temperature of some based solutions and electroless nickel plating solutions. The change of pH with changing temperatures is explained by view of the thermal dynamic and the practical measurements.

• Asian-Australasian Journal of Animal Sciences
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• 제14권6호
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• pp.858-861
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• 2001

Near Infrared spectroscopy was applied to the samples of processed pork to see the effect of grinding on chemical components analyses. Data from conventional chemical analyses of moisture, fat, protein, NaCl were put into calibration model by NIR of reflectance mode. The other properties observed were pH and color parameters ($L^*,\;a^*,\;b^*$). Spectral ranges of 400~2500 nm and 400~1100 nm were compared for color parameters. Spectral ranges of 400~2500 nm and 1100~2500 nm were compared for chemical components and pH. Different spectral ranges caused little changes in the coefficients of determination or standard errors. $R^{2,}s$ of calibration models for color parameters were in the range of 0.97 to 1.00. $R^{2,}s$ of calibration models of intact sausages for moisture, protein, fat, NaCl and pH were 0.98, 0.89, 0.95, 0.73 and 0.77, respectively using spectra at 1100~2500 nm. $R^{2,}s$ of calibration models of ground sausages for moisture, protein, fat, NaCl and pH were 0.97, 0.91, 0.97, 0.42 and 0.56, respectively using spectra at 1100~2500 nm.

• 한국식품조리과학회지
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• 제9권1호
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• pp.43-51
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• 1993

Buckwheat protein isolate was tested for the effects of pH, addition of sodium chloride and heat treatment on solubility, emulsion capacities, emulsion stability, surface hydrophobicity, foam capacities and foam stability. The solubility of buckwheat protein isolate was affected by pH and showed the lowest value at pH 4.5, the isoelectric point of buckwheat protein isolate. The solubility significantly as the pH value reached closer to either ends of the pH, i.e., pH 1.0 and 11.0. The effects of NaCl concentration on solubility were as follows; at pH 2.0, the solubility significantly decreased when NaCl was added; at pH 4.5, it increased above 0.6 M; at pH 7.0 it increased; and at pH 9.0 it decreased. The solubility increased above $80^{\circ}C$, at all pH ranges. The emulsion capacity was the lowest at pH 4.5. It significantly increased as the pH approached higher acidic or alkalic regions. At pH 2.0, when NaCl was added, the emulsion capacity decreased, but it increased at pH 4.5 and showed the maximum value at pH 7.0 and 9.0 with 0.6 M and 0.8 M NaCl concentrations. Upon heating, the emulsion capacity decreased at acidic pH's but was maximised at pH 7.0 and 9.0 on $60^{\circ}C$ heat treatment. The emulsion stability was the lowest at pH 4.5 but increased with heat treatment. At acidic pH, the emulsion stability increased with the increase in NaCl concentration but decreased at pH 7.0 and 9.0. Generally, at other pH ranges, the emulsion stability was decreased with increased heating temperature. The surface hydrophobicity showed the highest value at pH 2.0 and the lowest value at pH 11.0. As NaCl concentrationed, the surface hydrophobicity decreased at acidic pH. The NaCl concentration had no significant effects on surface hydrophobicity at pH 7.0, 9.0 except for the highest value observed at 0.8 M and 0.4 M. At all pH ranges, the surface hydrophobicity was increased, when the temperature increased. The foam capacity decreased, with increased in pH value. At acidic pH, the foam capacity was decreased with the increased in NaCl concentration. The highest value was observed upon adding 0.2 M or 0.4 M NaCl at pH 7.0 and 9.0. Heat treatments of $60^{\circ}C$ and $40^{\circ}C$ showed the highest foam capacity values at pH 2.0 and 4.5, respectively. At pH 7.0 and 9.0, the foam capacity decreased with the increased in temperature. The foam stability was not significantly related to different pH values. The addition of 0.4 M NaCl at pH 2.0, 7.0 and 9.0 showed the highest stability and the addition of 1.0 M at pH 4.5 showed the lowest. The higher the heating temperature, the lower the foam stability at pH 2.0 and 9.0. However, the foam stability increased at pH 4.5 and 7.0 before reaching $80^{\circ}C$.

• Journal of Plant Biology
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• 제8권1_2호
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• pp.19-23
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• 1965

Interaction occuring among the different Ca concentrations, pH and temperatures in the promotive effect of Ca in pollen growth was studied by using pollen from Crinum asiaticum and Cryptostegia grandiflora. Data for pollen tube elongation were found to be more indicative of representing the promotive action of Ca ion in pollen growth than those for pollen germination, and were served to evaluate the experimental results. The pollen growth increased as the concentration of Ca increase. The optimal pH range for pollen growth shifted from the lower pH to the higher as the concentration of Ca increase. The characteristic Ca effect was disappeared, and no pH effect at various ranges was observed when pollen grains were grown at the low temperature(8$^{\circ}C$). The Ca effect became quite pronounced if temperature were raised. The Ca effect became even mroe striking if the condition was in higher pH ranges (weak alkaline). Higher pH ranges were found to be more favorable for the Ca action, whereas higher temperature was required to bring about more pronounced Ca effect. Thus, the longest pollen tube was obtained with the highest pH, temperature adopted for the medium supplemented with Ca in the present experiment, and the shortest tube with the lowest temperature applied at the highest pH. Pectin synthesis in pollen tube was considered as a metabolic process, whereas Ca binding in pectin of the pollen tube wall as non-metabolic in nature. Disappearance of Ca effect at the low temperature was probably brought about by blocking the metabolic synthesis of pectin, and nonmetabolic Ca binding seems to take place more extensively with higher concentrations of Ca and at higher pH levels than the lower.

• 열처리공학회지
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• 제10권3호
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• pp.198-208
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• 1997

The-steady-state creep mechanism and behavior of Zircaloy-4 used as cladding materials in PWR have been investigated in air environment over the temp, ranges from 600 to $645^{\circ}C$ and stress ranges from 4 to $7kg/mm^2$. The stress exponents for the creep deformation of this alloy, n were decreased 4.81, 4.71, 4.64, and 4.56 at 600, 615, 630 and $645^{\circ}C$, respectively; the stress exponents decreased with increasing the temperature and got closer to about 5. The apparent activation energies, Q, were 62.1, 60.0, 57.9 and 55.4 kcal/mole at stresses of 4, 5, 6, $7kg/mm^2$, respectively; the activation energies decreased with increasing the stress and were close to those of volume self diffusion of Zr in Zr-Sn-Fe-Cr system. In results, it can be considered that the creep deformation for Zircaloy-4 was controlled by the dislocation climb over the ranges of this experimental conditions. Larson-Miller parameter, P, for the crept specimens was obtained as P=(T+460)(logt,+23). The failure plane observed by SEM slightly showed up intergranular fracture at this experiment ranges. However, it was essentially dominated by the dimple phenomenon, which was a characteristics of the transgranular fracture.

• Fisheries and Aquatic Sciences
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• 제3권3_4호
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• pp.188-194
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• 2000

A protease purified from hepatopancreas of shrimp, Penaeus japonicus, had maximum activity at $70^{\circ}C$ and in neutral and alkaline pH ranges. Specific activity at optimum reaction condition of the protease was estimated to be approximately 12 U/mg/min. The protease was stable in neutral and alkaline pH ranges and activity was retained after heat treatment at $50^{\circ}C$ for 30 min. Apparent $K_m$ and $V_{max}$ value against casein substrate were estimated to be $0.29\%$ and $7.8see^{-1}$, respectively, and those against N-CBZ-L-tyrosine p-nitropheny1 ester (CBZ­Tyr-NE) were 0.38 mM and $2,400 see^{-1}$, respectively. The N-termina1 sequence of the protease showed high homology to the trypsin from same species and the proteases from shrimp. Myosin heavy chain (MHC) from shrimp tail meat was the most susceptible to the protease and actin/tropomyosin were degraded progressively during 4 hr incubation, but to a lesser degree than MHC.

• 한국식품위생안전성학회지
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• 제31권4호
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• pp.304-309
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• 2016

본 연구에서는 고려엉겅퀴 추출물에 대한 열안정성, pH 안정성을 조사하고자 고려엉겅퀴 주정추출물은 온도별(4, 25 및 $50^{\circ}C$), pH별(4.0, 7.0, 및 10.0)로 저장하면서 추출물의 pectolinarin 함량, 총 페놀 함량, 2,2-diphenyl-1-picrylhydrazyl (DPPH) 라디칼 소거능 및 FRAP assay를 분석하였다. 고려엉겅퀴 추출물의 pectolinarin 함량은 저장기간이 증가함에 따라 다소 감소하는 경향을 보였으며, 온도에 의한 영향보다 pH에 의한 영향이 큰 것으로 나타났다. 총 페놀 함량도 pectolinarin 함량과 저장기간이 증가함에 따라 같이 감소하는 경향을 보였으며 저온($4^{\circ}C$)에서 보다 높은 온도인 $25^{\circ}C$와 $50^{\circ}C$에서 큰 감소치를 보였고 산성(pH 4.0)과 중성(pH 7.0)에서는 비교적 변화가 적었다. 항산화 활성은 저장기간이 증가함에 따라 DPPH 라디칼 소거능은 감소하는 경향을 보였으나 FRAP은 온도별, pH별 저장조건에 따른 큰 변화를 보이지 않았다. 이상의 결과를 고려해 볼 때, 고려엉겅퀴 주정 추출물은 산성(pH 4.0)과 중성(pH 7.0)조건에서 저온($4^{\circ}C$) 저장 시 추출물의 안정성을 최적화 할 수 있을 것으로 판단되었다.

• 자원리싸이클링
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• 제2권2호
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• pp.1-8
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• 1993

부선법에 의하여 폐수속에 함유되어 있는 철이온을 제거하기 위한 몇가지 효과적인 포수제와 최적 조건들을 알아본 실험의 결과를 요약하면 다음과 같다. 음이온 포수제인 sodium lauryl sulfate에 의해서 2가와 3가 철은 각각 pH 7과 6에서 효과적으로 제거되었다. 음이온 호수제인 aeropromotor 845에 의해서 2가와 3가철은 모두 pH pH 10~11영역에서, 3가철은 pH4~10영역에서 효과적으로 제거되었따. 따라서, 2가와 3가철은 2가와 3가 철이온침전점 이상으로 단순히 용액의 pH값을 조절하여 수산화철 침전으로 만든 다음 부선법에 의하여 효과적으로 제거된다고 할 수 있다. 그때의 효과적은 pH 조절제는 NaOH와 $Na_2CO_3$였고, 효과적인 포수제는 aeropromotor 845와 trimetyl dodecyl ammomum chloride 이었다.