• Journal of the Korea institute for structural maintenance and inspection
• /
• v.16 no.4
• /
• pp.122-129
• /
• 2012

In this study, environmental problems(i.e., pH elevation and $Cr^{6+}$ detection) occurred by using the cement grout made from CA(calcium aluminate) were evaluated using viscosity agents(MC, chelate polymer). Ordinary portland cement and blaste-furnace slag cement were used by main materials and ACC(blended mixture of calcium aluminate) were used by accelerator for hardening of grout. In addition, viscosity agents were used for preventing pH elevation and heavy metal detection from grouting materials. From the results, it was noted that when chelate polymer was used, pH elevation and $Cr^{6+}$ detection were minimized. However, other cases showed higher pH elevation and $Cr^{6+}$ detection. At test 1 day, $Cr^{6+}$ detection with age presented over 97% of total value and, after that, additional increase was not distinct. As a result of this study, it was acknowledged that, to control pH elevation and heavy-metal (like $Cr^{6+}$) detection, the usage of BSC and chelate polymer is a very useful fact.

• Journal of Korean Ophthalmic Optics Society
• /
• v.9 no.2
• /
• pp.381-389
• /
• 2004

To investigate changes of multi-purpose solutions for soft contact lens(MPS) depending on using period or keeping temperature, we evaluate four brands of MPS. No significant difference was seen in protein deposit removing efficacy after samples had used for 24 weeks and kept at $4^{\circ}C$, $20^{\circ}C$ or $30^{\circ}C$. The pH values of the samples of 4 brands measured weekly over the 24 week testing period. The initial average pH value of samples were 7.0, 7.5, 7.6 or 8.2. One brand of MPS was in the range of the threshold for ocular awareness, which is outside the zone of 6.6 ~ 7.8. During the testing period, the pH value were decreased in using period-dependent manner. At the 24th week, the average pH values of samples turned to 6.6, 7.2, 7.2 or 7.7. However, the difference of keeping temperature was not associated with decreased levels of pH values. After 24 weeks, one of total 36 samples was contaminated by bacteria. Furthermore, the change of components was shown after 24 weeks in the analysis using thin layer chromatography and the analysis of UV absorption pattern. The results of our study provides that the keeping temperature of MPS is not the important factor of changes of MPS, but the using period of MPS can cause contact lens wearers discomfort.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.28 no.4
• /
• pp.443-450
• /
• 1995

Listeria monocrogenes has been increasingly recognized as an important food poisoning and pathogenic bacterium which is Gram positive, non spore forming and facultative anaerobic rod shape. Bacteriological and physiological characterization of L. monocytogenes YM-7 isolated from a patient was performed. Optimum growth condition of 1. monocytogenes YM-7 was at $37^{\circ}$, pH 8.0 and $0\%$ sodium chloride in tryptic soy broth, and then it grew pretty well in the range of $8-40^{\circ}C,\;pH 5.0-10.0\;and\;up\;to\;7\%$ of sodium chloride in the medium. The highest hemolysin activity of hemolysin produced by L. monocytogenes YM-7 was shown in the stationary phase of its growth. Hemolysin produced by the isolated strain was stable at $4^{\circ}C\;and\;pH\;6.0-8.0, while it was gradually unstable by increasing the storage temperature.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2008.05a
• /
• pp.1848-1852
• /
• 2008

본 연구에서는 판교신도시 개발에 따른 도시화에 의한 수문 수질 영향을 평가하기 위한 목적으로 2004년 8월부터 운중천과 금토천 유역에 대해 수문관측망을 구성하여 시험유역으로 운영하고 있다. 판교시험유역은 매송2교를 최종 출구점으로 하는 운중천 유역으로서 도시화 진행이 예상되는 운중천 본류 구간과 달리 비슷한 유역면적의 지류인 금토천 구간은 비교적 자연상태로 유지될 예정이기 때문에 향후 두 하천구간에서의 수문현상을 비교 분석하기에 적합한 장점을 가지고 있다. 현재 운중천 상류의 운중저수지 지점과 하류의 판교교 지점, 금토천 상류의 내동교 지점과 하류의 삼평교 지점, 그리고 두 하천이 합류되어 탄천과 합류하기전의 매송2교 지점에 4개의 하천수위관측소(판교교, 삼평교, 매송2교, 내동교), 3개의 우량관측소(매송, 내동, 운중), 그리고 운중지 저수위 및 용수로 수위관측소 등 총 8개 지점에 대하여 초음파 수위계 5개, 압력식 수위계 5개, 전도형 강우계 3개가 설치되어 운영중이다. 2005년도부터는 유량 측정과 동시에 유사량 및 수온, pH 등의 수질 항목들에 대해서도 정기적인 측정을 하고 있으며, 2007년 갈수시와 홍수시에 총 62회에 걸친 유량 측정을 통해 지점별 수위-유량 관계를 도출하고, $7{\sim}8$월 홍수시에는 시간별 시료도 수집하여 강우시의 실시간 유사량 및 수질 변화도 함께 검토하였다.

• The Journal of Engineering Geology
• /
• v.13 no.2
• /
• pp.257-266
• /
• 2003

Jurassic granites of three sites, Pocheon, Geochang and Habcheon, were tested to investigate the effect of microcracks on Physical and mechanical properties of the granites. Fifteen oriented core specimens were used for the physical property test. The test result shows that porosity is almost proportioned to water content. P-wave velocity is the highest in the direction of axis ‘H’, intersection of two major microcrack sets and the lowest in the axis ‘R’, normal to the rift plane. Compressional strength tests were carried out for each core specimen taken parallel with axes ‘R’, ‘G’ and ‘H’, measuring strains. The results revealed a strong correlation between microcrack orientation and other mechanical properties such as rock strength.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.9
• /
• pp.4197-4203
• /
• 2013

In order to investigate the heating performance of multi-heat pump applying an inverter compressor, the experiment on heat pump with 3 indoor units was performed under the heating standard and heating low-temperature conditions. The performance data of heat pump with 3 indoor units were measured by the multi-psychrometric calorimeter. The operation characteristics and the behavior of the refrigerant cycle of the heat pump with 3 indoor units were understood from the heating capacity, heating COP, and P-h diagram by indoor-unit combination. The present experimental results show that the operating load and performance of the multi-heat pump depends on the indoor-unit combination. The heating capacity and heating COP of the low temperature condition were smaller than those of the standard one. Also the refrigerant cycles on indoor-unit combination were analyzed by using P-h diagram.

• Korean Journal of Food Science and Technology
• /
• v.25 no.4
• /
• pp.404-406
• /
• 1993

In order to detect the gelation of ultrahigh temperature (UHT) treated market milks during storage at 20+1C, the free amino groups were quantified with 2,4,6-trinitrobenzene sulfonic acid, and the measurement of pH values and the alcohol test were monthly carried out. The average tree amino groups were $0.94{\sim}1.11{\mu}M$ at 1 month, $1.95{\sim}2.17{\mu}M\;at\;5{\sim}6$ month and $4.95{\sim}6.36{\mu}M$ at 12 month. The pH values at the same time as above were $6.72,\;6.49{\sim}6.55\;and\;6.14{\sim}6.16$, respectively. The alcohol test showed positive results at $5{\sim}6$ month, which could indicate the casein instability and beginning of gelation. These results suggest that the gelation of UHT market milks could he predicted through checking some chemical parameters weekly and be helpful for quality control.

• Korean Journal of Poultry Science
• /
• v.20 no.4
• /
• pp.189-196
• /
• 1993

True amino acid availability (TAAA) and true metabolizable energy(TME) values of 8 protein feedstuffs were determined by feeding three roosters exactly 30g of each protein feedstuff after 36h of fasting. From each rooster excreta were collected for 36 h. TAAA were significantly(P<0.01) different among protein feedstuffs. TAAA was highest in fish meal(96.1%), followed by corn gluten(91.2%), rapeseed meal(88.8%), soybean meal(88.7%), meat meal(87.2%), canola meal(86.1%), cottonseeed meal(82.6%) and feather meal(82.5%). Available Iysine values obtained by TAAA method were highly correlated(P<0.01) with those obtained by chick bioassay(CBA) and FDNB method. TME was highest in corn gluten(4,011kcal/kg, as fed basis), followed by fish meal(3,906), feather meal(3,098), soybean meal(3,007), meat and bone meal(2,631), canola meal(2,326), cottonseed meal(2,246) and rapeseed meal(2,120).

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.26 no.1
• /
• pp.92-97
• /
• 1997

Beverages using mountain edible herbs(MEH) were formulated by determining optimum ratio of juices of MEH to several other ingredients. Fermented beverages were made by mixing juices(1 volume) fermented with Lactobacillus helverticus with syrup(3 volumes), followed by homogenization and flavoring . The general analysis and quality change of the beverages during storage were Peformed. The analysis of the beverages showed that the pH of Synurus deltoides and Cirsium sctidens were 3.8 and 3.7, titratable acidities were 0.50 and 0.49, optical densities were 1.201 and 1.119, respectively, The pH and color were not significantly changed when Synurus deltoides and Cirsium sctidens were stored at room temperature and 37$^{\circ}C$ for 6 months. The pH of Synurs deltoides beverage ranged 3.95~3.96 and pH of Cirsium sctidens was 3.83~3.95 at room temperature and 3.87~3.98 at 37$^{\circ}C$, respectively. The analysis of fermented beverages showed that pHs of Synurus deltoides and Cirsium sctidens were 3.65 and 3.70, titratable acidities were 0.57 and 0.60. Solids-non-fat were 3.2 and 3.1, and total counts of lactic acid bacteria were 2.5$\times$10$^{8}$ and 4.0$\times$10$^{8}$ , respectively. The changes of pH and titratable acidities stored at 4$^{\circ}C$ for 15 days were 3.39~3.56 and 0.61~0.81 for Synurus deltoides and 3.48~3.67 and 0.60~0.78 for Cirsium sctidens, respectively.

• Plant Journal
• /
• v.17 no.4
• /
• pp.35-40
• /
• 2021

In this study, a technical characteristic test was conducted on the gas turbine generator system of Seoincheon Combined cycle no.6 to derive and verify the model constants. As a result of the generator maximum/minimum reactive power limit test, the maximum reactive power limit is 80 MVar and the minimum is -30 MVar. The generator uses the GENROU model, the field time constant (T'do) is 4.077 s, and the inertial constant (H) is 5.461 P.U. Excitation system used ESST4B model to derive and verify model constants by simulating no-load 2% AVR step test, PSS modeling derived from PSS2A model constants, and simulated and compared measurement data measured when PSS off/on Did. The GGOV1 model was used for the governor-turbine, and the numerical stability of the determined governor-turbine model constant was verified by simulating a 10% governor step test through the PSS/E simulation program