• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1996.10a
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• pp.64-66
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• 1996

수경재배에서 요구되는 최적의 배양액 pH는 5.5-6.5 이고, pH를 최적의 상태로 조절해 주는 방법으로 비료의 흡수생리를 이용하는 방법과 화학적인 산알칼리 용액을 이용하여 조절해 주는 방법이 있다. 이러한 pH 조절은 자동적으로 행해야 효과가 크며 본 실험은 흡수생리적인 면에서 산 혹은 알칼리 비료를 화학적인 산 알칼리와 비교하여 pH 조절효과의 차이를 보고자 하며 생육제어시스템 중 pH의 자동계측 및 제어를 통해서 계속적인 pH의 안정적인 수준을 유지하면서 상품성과 품질이 우수한 작물을 생산하고자 이 실험을 수행하였다. (중략)

• Journal of Bio-Environment Control
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• v.5 no.2
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• pp.145-151
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• 1996

The effectiveness of physiological or chemical acid - alkali solution was investigated as the method to control pH value of nutrient solution in hydroponics dynamically. Lettuces were cultivated using NH$_4$H$_2$PO$_4$ as physiological acid and NaNO$_3$ as physiological alkali or H$_2$SO$_4$ as chemical acid in dynamic control system. The pH of nutrient solution was controlled satisfactorily in the range of pH 5.5-6.5, regardless of treatments. Chemical acid changed pH of solution faster than chemical acid when supplied to the nutrient solution. Any of them did not show any harmful symptom. It is recommended that chemical acid is preferred during the growing stage and physiological acid like as NH$_4$H$_2$PO$_4$ is preferred from several days before harvest stage.

• Korean Journal of Microbiology
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• v.38 no.3
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• pp.168-172
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• 2002

Budding yeasts maintain an effective system to regulate intracellular pH in response to environmental pH fluctuation. In a previous study we reported that SHC1 plays a role in cell growth at alkaline condition, not at acid pH. We constructed a null mutant deleted an entire open reading frame for SHC1. To test whether the retardation in cell growth was caused by the absence of intracellular pH buffering capacity, we measured intracellular pH with a pH-sensitive fluorescent dye, C.SNARE. The intracellular pH of the mutant cell was much higher than that of wild-type cells, indicating that the mutant cells lack some types of buffering capacity. We also investigated the level of $Na^＋ and K^＋$ content with atomic mass spectroscopy after alkali shock. Wild-type cell showed a higher level of intracellular K^＋$ content, whereas there was no difference in $Na^＋$ level. The result suggested that K^＋$ is more important in the regulation of intracellular pH in yeasts.

• Journal of Adhesion and Interface
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• v.4 no.3
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• pp.9-13
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• 2003

In this paper, the effects of crosslinking agent and pH controlling agent on adhesive properties and water solubility of water soluble acrylic pressure sensitive adhesives were studied by adding the crosslinking agents or pH controlling agents after the polymerization. the tack, cohesive strength, and peel strength were measured to evaluate adhesive properties. the turbidity was also measured to evaluate water solubility of pressure sensitive adhesives. When crosslinking agent was added less than 0.2 wt%, tack increased and cohesive strength and peel strength decreased with increasing concentration. When crossinking agent was added more than 0.2 wt%, the results were opposited. When pH controlling agent was added, tack and water solubility decreased and peel strength and cohesive strength increased with increasing concentration. the influence of pH controlling agents on adhesive properties and water solubility of pressure sensitive adhesive increased in the order of lithium hydroxide, potassium hydroxide and sodium hydroxide.

• Journal of Bio-Environment Control
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• v.10 no.1
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• pp.50-54
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• 2001

Effect of NO$_3$:NH$_4$ratio and pH of nutrient solution on nitrate content of leaves was investigated for leaf lettuce(Lactuca sativa L.) grown by a deep flow technique. Ratios(in me.L$^{-1}$ ) of NO$_3$:NH$_4$tested were 12:1, 10:3 and 8:5. The treatment of 8:5 NO$_3$:NH$_4$ratio had two solutions, one with uncontrolled pH and the other with automatically controlled pH. Solution pH continuously increased in 12:1 NO$_3$:NH$_4$treatment. Solution pH decreased gradually more as NH$_4$ratio increased. Treatment of 8:5 NO$_3$:NH$_4$with automatic pH control satisfactorily maintained the solution pH in the range of pH 5.5-6.0. Nitrate content in leaves was the greatest in treatment of 12:1 NO$_3$:NH$_4$ and the least in treatment of 8:5 NO$_3$:NH$_4$with automatic pH control. Fresh weight decreased in treatments of 10:3 and 8:5 NO$_3$:NH$_4$, whereas it increased in treatments of 12:1 and 8:5 NO$_3$:NH$_4$with pH control. It was concluded that the growth and leaf nitrate content were the greatest in high NH$_4$treatment with automatic pH control.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.26 no.1
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• pp.59-80
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• 2000

본 연구는 dermal equivalent를 이용하여 AHA류(lactic acid, glycolic acid, citric acid 및 malic acid) 및 보습 원료(sodium hyaluronate, glycerine, natural carbohydrate complex)에 대한 wound healing 효과 및 그 기작을 알아보기 위한 것이다. AHA류 및 보습 원료의 독성은 dermal equivalent를 이용하여 m assay를 실시한 후 적정 농도를 petri dish위에 조성한 dermal equivalent에 처리하였다. 그리고 wound healing 효과를 알아보기 위하여 collagen 수축률을 측정하였다. 또한 collagen 합성을 촉진하는 것으로 잘알려진 vitamin C도 함께 처리하였다. AHA류의 경우 평균 pH 2-3으로 매우 낮기 때문에 4N NaOH를 이용하여 pH를 6-7사이로 조절한 sample를 함께 실험하였다. 보습 원료의 경우 전반적으로 10% 이상의 높은 NR$_{50}$보여 주었다. 특히 sodium hyaluronate(1% stock solution)의 경우에는 16% NR$_{50}$를 보여 주었다. pH를 6-7로 조절한 AHA류의 경우에는 전반적으로 0.6% 내외의 NR$_{50}$를 보이는 가운데 lactic acid는 상대적으로 높은2% NR$_{50}$를 보여 주었다. Collagen 수축률 측정 실험 결과에서는 2% sodium hyaluronate(1% stock solution)가 대조군에 비하여 처리 후 2일째 25%내외의 향상된 수축률을 보여 주었다. pH를6-7로 조절한 AHA류 중 0.1%의 malic acid의 경우에서는 대조군에 비하여 처리 후 1일째 및 2일째 각각 28% 및 35%의 수축률을 보여 주었으며 pH를 6-7로 조절한 0.1% vitamin C에서도 유사한 결과를 보여 주었다. 반면에 pH를 6-7로 조절한 0.1% citric acid의 경우에는 10-20%의 낮은 수축률을 보여 주었다. MTT assay를 이용한 UV 조사 후 pH를 6-7로 조절한 AHA류의 repairing UV damage 효과에 대한 실험에서 0.1% 및 0.01%의 malic acid와 0.01% citric acid은 irradiation control에 비하여 약 10% 이상 세포수를 증가시켰다. 그러나 예외적으로 citric acid의 경우 0.1% 농도에서 오히려 20%내외로 세포수가 감소되는 경향을 보여주었다. 그리고 lactic acid 및 glycolic acid는 두드러지는 효과를 나타내지 않았다. Collagen 합성을 측정 실험에서는 pH를 6-7로 조절한 AHA류에서는 대조군에 비하여 상대적으로 12-19% 더 합성을 촉진하였다. 반면에 pH가 2-3인 AHA류의 경우에는 대조 군과 유사하거나 조금 낮은 합성율을 보여 주었다.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.3
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• pp.5-14
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• 2020

This study aims to survey the effect of sulphuric acid (H₂SO₄) treatment for pH adjustment with 6.5 and 7.0 regarding ammonia volatilization on chemical content change in the aerobic liquefying process of co-digesate swine manure and apple pomace. The digestates of swine manure was aerated with 0.3 ㎥ air/㎥·min for 60 days. The untreated digestate showed the increased pH and decreased contents of electrical conductivity (EC) and total nitrogen (T-N). The untreated digestate had a high concentration of NH₃ with 172.6 mg/L, but, ammonia (NH₃) concentration of H₂SO₄-treated digestate was significantly lower than that of untreated digestate. The H₂SO₄-untreated digestate for retaining aeration showed a decreased concentration of 47.2% of ammonium nitrogen. While, the H₂SO₄-treated digestate had a high concentration of ammonium nitrogen compared to the untreated digestate. Also, the H₂SO₄ treatment affected to increase the contents of nitrogen and phosphoric acid content. Therefore, the pH adjustment with H₂SO₄ might be a useful method for the decreased ammonia concentration and nitrogen maintenance in the aerobic liquefying process of swine manure digesate.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.116-119
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• 2001

마이크로 크기 상업용 칠 분말의 반응성 향상을 위한 변수로 포기 반응 조건인 pH 조절과 산 세척을 통한 철 분말의 표면처리를 선정하고 질산성 질소를 처리대상오염 물질로 선택하여 철 분말에 의한 질산성 질소 처리 실험을 수행하였다. 산을 이용한 초기 pH조절에 의한 반응성 향상 실험에서 가장 좋은 pH 조절제는 염산이었으며 critical pH는 2 였고 산 세척에 의한 반응성 향상 실험에서는 산 세척한 철 분말의 반응성이 그렇지 않은 철 분말보다 현저하게 좋았으며 황산의 세척능이 염산보다 더 뛰어남을 알 수 있었다. 본 연구를 통하여 초기 반응조건의 조절과 철 분말의 산 세 척을 통한 전처리로 기존의 마이크로 크기 상업용 철 분말이 지닌 반응성의 향상을 꾀하였으며 수중의 질산성 질소 처리실험을 통하여 최적의 반응조건을 확립하였다.

• Journal of Bio-Environment Control
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• v.4 no.2
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• pp.203-210
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• 1995

Using the programmable logic controller (PLC), a kind of microcomputer, a facility to control EC and pH automatically in nutriculture of tomato was developed. A program for the automatic control of nutriculture was written in ladder diagram language. EC and pH levels of nutrition solution could be maintained at 1.70-1.72 and 6.1-6.5, respectively, during the entire growing period. Better fruits and higher yield were obtained in automatic control plot than in the control plot. Inorganic elements in plant were higher in the former than in the latter.

• Korean Journal of Food Science and Technology
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• v.21 no.2
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• pp.180-184
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• 1989

Clarification of the juice extracted from stored Fuji apples was studied with pectolytic enzyme and pH control, separately and in combinations. In the separated treatment, the clarity of the juice was increased with the treated enzyme amount. The juice adjusted pH to 3.5 with malic acid had the highest clarity in pH range from 3.5 to 5.0, but this juice was not acceptable because of high acidity. In combination of the two treatment, the clarity of the juice treated with the enzyme at pH 4.0 was higher than that of the juice without the enzyme, and the juice with ligh trasmittance of about 92% could be obtained at the pH by addition with one-third amount of enzyme which was used for clarification of the juice extracted from the fresh apples at harvesting season.