• Analytical Science and Technology
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• v.14 no.3
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• pp.230-237
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• 2001

In general, the pH measurement follows calibration of glass electrode system using pH standard solution. When pH is measured at constant temperature, uncertainty factors are mainly related to the accuracy of pH standard solution and the accuracy and precision of glass electrode. Participants in this proficiency test were the volunteers trying to know the distribution of the measured pH values for the same sample and the sources of error through 1998 and 1999. The samples for proficiency test are phosphate salt standard solutions specially prepared in KRISS, of which pH values were 6.860, 7.415(at $25^{\circ}C$), and the stability test was performed for the same periods of proficiency test. The results of the proficiency test were plotted according to Youden plot, which shows whether the error is random or systematic. The results of Youden plot showed that the source of error was from the systematic effect of laboratories in each year. This shows that the source of error is the standard solutions used in laboratories.

• Journal of the Korea Concrete Institute
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• v.29 no.1
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• pp.85-92
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• 2017

This study examines the characteristics of mortar mixed with various boron compounds. The adapted boron compounds, classified into acid, slightly alkaline and strongly alkaline with respect to the value of the pH are acid-based boron (AA), low-alkaline-based boron (AB), and high-alkaline-based boron (HB). The pH test, setting test and compressive strength test are performed to evaluate the physical and chemical properties of mortar, and SEM imaging is conducted to analyze the microstructure of mortar. The measured pH shows that the specimens mixed with boron compounds have lower pH than the basic mortar without boron and that loss of pH occurs according to time. The setting test reveals that the initial and final setting times of the specimens mixed with boron compounds occur later than the basic mortar, which disagrees slightly with the previous literature stating that the setting time can be shortened according to the alkalinity. From the compressive strength test and SEM imaging results, it is recommended to determine the optimal content of boron considering type and composition of the boron compounds.

• Food Science of Animal Resources
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• v.20 no.2
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• pp.152-158
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• 2000

This study was conducted to investigate the influence of feeding illite(yellow soil component) on meat quality of pork. 40 pigs were fed with commercial formulated feed (control group) and 1% illite added feed(treatment group). Pigs grown up to 100~110kg of weight were slaughtered in commercial abattoir. After chilling for 24hours, samples were collected from M. longissimus dorsi muscle, and stored at $4\pm$$1^{\circ}C$ for analyses. The physico-chemical properties was determined during storage days as follows. Ultimate pH was not significantly different between control and treatment(pH 5.58 and 5.60, respectively). Water-holding capacity measured using filter paper press method of the treatment group was slightly higher than that of the control group. Cooking loss of treatment group were significantly lower than that of the control group at 1 and 7 days(p〈0.05). Shear force between control and treatment group was not different. L*- and a*-value were not significantly different between the two groups(p〉0.05), but b*-value of treatment group was lower than that of the control group(p〈0.05). The drip loss of all samples was increased with storage days, and that of the treatment group was significantly lower than that of the control at 1 and 3 day storage. Meat color measured using NPPC pork quality standards was not significantly different between the two groups(p〉0.05), but marbling content of the treatment group was significantly higher than that of the control group(p〈0.05). Sensory characteristics of, flavor taste and tenderness did not show significant differences(p〉0.05), but juiciness of the treatment group showed higher value than that of the control group(p〈0.05)

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1626-1630
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• 2006

본 논문의 목적은 설마천 시험유역을 대상으로 2005년의 신뢰성 있는 수문 수질자료를 바탕으로 유역의 유출거동에 따른 수질인자와의 상관관계를 분석하는데 있다. 시험유역에서는 10분 단위의 연속적인 우량 및 수위관측과 연간 30회 이상의 유량측정성과를 통하여 수위-유량관계곡선식을 개발하여 유량을 산정하고 있으며, 수질분석을 위한 시료채취는 유량측정시 현장에서 채취하여 실험실에서 분석하였다. 실험실에서 분석한 항목은 DO, BOD, COD, T-N, T-P, F, Cl, $NO_3-N,\;SO_4$, pH, 전기전도도로 총 11개 항목으로 수질측정은 우기가 시작되는 시기인 $6{\sim}9$월에 집중적으로 측정 분석하였으며, 강우가 시작되기 직전과 강우가 시작되어 유량이 증가되는 시기를 선정하여 각각 20회의 시료를 채취하여 분석하였다. 측정된 수질자료를 이용하여 2개 측정지점에 대한 각 항목간의 상관관계를 분석하였으며, 강우가 시작되기 직전과 강우기에 대하여 각 항목간의 상관분석을 수행하였다. 그리고, 선행강우의 일수에 따라 유출의 거동에 따른 BOD, COD, DO, T-N, pH의 농도변화를 비교 검토하였다. 2개 지점의 상관분석 결과는 오염물질간 상관성이 유사한 경향을 나타내었으며, 강우가 시작되기 직전과 강우기에 대한 각 항목간의 상관분석 결과는 유량은 전기전도도 항목과 상관도가 높게 나타났을 뿐 다른 항목은 없었으며, 수질항목간 상관도도 유기물질들 사이에서만 상관성을 나타내었다. 비강우기에는 질소성분의 항목과 전기전도도가 높은 상관도를 나타내었지만 강우기에는 유기물질과 질소성분의 항목간에 상관성이 있는 것으로 나타났다. 그리고, 선행강우의 일수에 따라 유출의 거동에 따른 BOD, COD, DO, T-N, pH의 농도변화를 비교 검토한 결과 선행강우일수가 클수록 전반적으로 DO, COD, BOD의 농도는 수문곡선의 형상과 비슷하게 증가 하였다가 감소하는 결과를 보이고 있으며, T-N은 선행강우일수가 큰 상태에서는 농도가 증가하였으나 선행강우가 작을수록 일정한 경향을 보이고 있다. 그리고, pH는 홍수기의 유량의 변화에 관계없이 일정한 값을 유지를 하고 있는 것으로 나타났다.

• Journal of Animal Science and Technology
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• v.52 no.2
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• pp.111-116
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• 2010

This study was conducted to determine the effects of different feeding levels on the number of fecal lactic acid-producing bacteria and fecal pH in horses. In Exp. 1, 6 female cross-bred horses ($332.4{\pm}50.4\;kg$, 5 year old) were fed 2% hay or 2% concentrates of BW for 30 d, and the number of fecal Lactobacilli and Streptococci was measured. For Exp. 2, 5 castrated Thoroughbred ($474.5{\pm}64.6kg$, 4 year old) and 5 female cross-bred horses ($343.6{\pm}56.3\;kg$, 5 year old) were allotted to high- or low-concentrates diets (5 levels) for 30 d in a $5{\times}5$ Latin square design, and the fecal pH was assessed. In Exp. 3, 3 castrated Thoroughbred ($482.6{\pm}53.3\;kg$, 4 year old) were fed high- or low-alfalfa hay diets (3 levels) for 30 d in a $3{\times}3$ Latin square design, and the fecal pH was measured. Feeding high-concentrates diets increased (P<0.05) the number of fecal lactic acid-producing bacteria (Lactobacilli and Streptococci) and decreased (P<0.01) the fecal pH. Feeding alfalfa hay with high-concentrates diet (2% alfalfa hay + 1% concentrates of BW) decreased (P<0.01) the fecal pH. These results showed that feeding high-concentrates diets increased lactic acid-producing bacteria in the large intestine and decreased the intestinal or fecal pH causing colic or laminitis, indicating that the proper fiber/concentrates (1:1) should be maintained in horses.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.3
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• pp.61-68
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• 2011

The pH of recycled aggregate is over 12 because of high alkalinity of cement. This high alkalinity give circumstance harmful effect. The high alkalinity of recycled aggregate can appear variously according to aggregate properties, elution time of alkalinity, aggregate size, and so on. This study analyzed recycled aggregate properties according to wet and dry type manufacture process; different test methods: waste official test, soil contamination official test, BS EN 1744-3 standard; elution time and different size to test effects of various condition. These test results can contribute to solving environmental problems by recycled aggregate. In the test results, pH of recycled aggregate was as higher as smaller particle size and as time elapsed. There was no difference between dry and wet type recycled aggregate except for difference according to elapsed time. Waste official test method got the highest pH value between pH test methods. So unified pH test method need to test recycled aggregate pH.

• Geotechnical Engineering
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• v.13 no.6
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• pp.123-138
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• 1997

Electroosmotic tests were performed on saturated marine clay specimens contaminated with lead to investigate the efficiency of the electrokinetic technique for removal of heavy metals from the cohesive soils. For this purpose, testing program included variable conditions such as the concentration of lead (500, 5, 000, 50, 000mg/kg), the level of electrical current (10, 50, 100 mA), operating duration (5, 15, 30days), and the application of three dirtferent chemicals for enhancement in efficiency. The pH of inflow and outflow, electroosmotic flow and electrical conductivity during the test, and the pH and the concentration of lead across the specimen after the test are presented. Test results came to the conclusion that the electrokinetic technique was very effective to remove heavy metals such as lead from the contaminated cohesive soil. Adding ecetic acid at the cathod to dissolve the procipitates of lead hydroxide as found to be effective for the enhancement of the efficiency in remediation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.1
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• pp.111-118
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• 2014

The present study concerns the leachability of alkali ions from hardened cement paste in terms of an increase in the pH together with the rate of alkali leaching. To evaluate the influence of mix design on the leaching capacity and rate of alkali, different water-cement ratios (W/C) and binders were used to manufacture paste specimens. The cement paste was made in the form of rectangular bucket where deionised water was subsequently supplied as solvent media. Then the specimen was wrapped in polythene film to avoid contact to atmospheric conditions, which may affect the water chemistry in the bucket. The pH of media was monitored until no further change in the pH value was observed, of which value then used to calculate the leaching capacity and rate. The influence of binder on the pH of solvent is more dominant than that of water to cement ratio: OPC paste produced the highest level of alkali leaching, whilst 30% PFA and 60% GGBS pastes imposed lower level of alkali leaching. After the monitoring of the pH, the inner bucket was ground with an increment of 1.0 mm to measure the leaching influence using the suspension consisting of paste powder and deionised water. It was found that the impact zone for OPC was about 7-8 mm, whilst 30% PFA and 60% GGBS had deeper impact depth of the alkali leaching.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.5
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• pp.750-760
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• 2009

In this study, the various effects of Salicornia herbacea, including antioxidative function, antibiotic, and anti-inflammatory effect, and the effect of sebiparous reduction due to intervention of the DHT hormone were investigated using. The result of this study Based on this analysis, the serum total cholesterol, triglyceride, and WBC were found to be significantly decreased and SOD, Ca, K, and Zn were shown to be significantly increased significantly in the group that received the SH pill group after trial fora 12 week trials. Testosterone and DHT were increased in the SH pill group, but it was not statistically significant. In the case of the skin condition measurements, the number of blackhead pores, skin oiliness, keratin and, MIC were significantly decreased, and the pH was decreased to normal pH in the SH pill group. Therefore, it was confirmed that overall skin condition was improved due to Salicornia herbacea diet. The results of this research result can contribute so demonstrate the potential of actively using that the Salicornia herbacea can be actively developed as a health supplement, and a medication.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.3
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• pp.43-49
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• 2016

Reliability characteristics of thin package-on-packages were evaluated using T/H (temperature/humidity) test at $85^{\circ}C/85%$ for 500 hours, TC (temperature cycling) test at $-40{\sim}100^{\circ}C$ for 1,000 cycles, and HTS (high temperature storage) test at $155^{\circ}C$ for 1,000 hours. The average resistance of the solder-bump circuitry between the top and bottom packages of 24 package-on-package (PoP) samples, which were processed using polyimide thermal tape, was $0.56{\pm}0.05{\Omega}$ and quite similar for all 24 samples. Open failure of solder joints did not occur after T/H test for 500 hours, TC test for 1,000 cycles, and HTS test for 1,000 hours, respectively.