• Journal of Bio-Environment Control
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• v.30 no.1
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• pp.27-36
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• 2021

A capacitive water sensor was developed to measure the capacitance over a wide part of a substrate using an insulated electrode plate (30 cm × 10 cm) with copper and Teflon attached on either side of the substrate. This study aimed to convert the capacitance output obtained from the condenser-type capacitance sensor into the substrate water content. The quantification experiment was performed by measuring the changes in substrate water weight and capacitance while providing a nutrient solution and by subsequently comparing these values. The substrate water weight and capacitance were measured every 20 to 30 seconds using the sensor and load cell with a software developed specifically for this study. Using a curve-fitting program, the substrate water content was estimated from the output of the capacitance using the water weight and capacitance of the substrate as variables. When the amount of water supplied was increased, the capacitance tended to increase. Coefficient of variation (CV) in capacitance according to the water weight in substrate was greater with the 1.0 kg of water weight, compared with other weights. Thus, the fitting was performed with higher than 1.0 kg, from 1.7 to 6.0 kg of water weight. The correlation coefficient between the capacitance and water weight in substrate was 0.9696. The calibration equation estimated water content from the capacitance, and it was compared with the substrate water weight measured by the load cell.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.6
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• pp.1292-1297
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• 2009

This study was performed to investigate solubility, dissolution rate and ash content of solid type fuel additive in gasoline and diesel in order to set up manufacturing standards. From the results, the unfiltered impurities were increased when the fuel additive was added on gasoline and diesel. Also, the unfiltered fuel additive was decreased with respect to increasing the pore size of the filter paper. When one gram of the fuel additive was dissolved in one liter of gasoline at room temperature, the best dissolution rate was about 2 hours. But, almost nothing was dissolved in diesel during 72 hours at $20^{\circ}C$ below zero. At the experiment of ash content, the gasoline which the fuel additive was melted in was showing 28 times more ash content than that was not including the fuel additive. Therefore, it seemed that almost all of ash content was caused by the fuel additive.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.697-702
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• 2001

This study was done to investigate effects of Korean mistletoe extract and lectin on serum GOT, GPT and $\alpha$-L-fucosidase activities and the preneoplastic lesion in chemically induced rat hepatocarcinogenesis. To attain the above objectives weanling Sprangue-Dawley male rats were fed modified AIN-76 diets containing 10% corn oil for 9 weeks. One week after feeding rats were intraperitonealy injected twice with a dose of diethylnitrosamine (DEN, 50 mg/kg body weight(BW)) and were provided 0.05% phenobarbita (PB) with drinking water from one week after DEN treatment until the end of experiment. For the same period as PB treatment, rats were injected mistletoe extract (10 $\mu\textrm{g}$/kg BW European mistletoe, 10 $\mu\textrm{g}$/kg BW and 100 $\mu\textrm{g}$/kg BW Korean mistletoe) and lectin(1 ng/kg BW, 10 ng/kg BW) twice a week. At the end of 9th week rats were sacrificed and the formation of hepatic glutthione S-transferase placental form positive (GST-P+) foci serum GOT, GPT and $\alpha$-L-fucosidase activities were determined. By treatment of mistletoe extract or lectin there were no significant effects on serum GOP, GPT and $\alpha$-L-fucosidase activities whereas those activities showed a tendency to increase by DEN treatment. The formation of GST-P+ foci was significantly decreased by mistletoe extract or lectin treatment especially in group of 100$\mu\textrm{g}$/kg BW Korean mistletoe. These results suggest that Korean mistletoe extract and lectin have a possibility to inhibit hepatocarcinogenesis of animals.

• Korean Journal of Food Science and Technology
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• v.42 no.3
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• pp.304-309
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• 2010

Instant Baekseolgi containing 0, 1, 2, and 3% trehalose prepared using a microwave oven, after which quality characteristics were investigated over 24 hr. The sample was prepared to internal and external parts. The moisture content of Baekseolgi without trehalose (control) was not reduced. However, the presence of trehalose reduced moisture content of two different groups (p<0.05). Weight reduction of Baekseolgi was decreased with increased threhalose content (p<0.05). The hardness, and chewiness of Baekseolgi with trehalose was decreased with increased trehalose (p<0.05). However adhesiveness, springiness, and cohesiveness were not significantly changed. The results of sensory evaluation showed that moisture and hardness were reduced between the internal and external parts of the Baekseolgi with increased trehalose (p<0.05). This study shows that the addition of trehalose to Baekseolgi had a positive impact on quality characteristics, including moisture content, weight reduction, texture, and sensory properites.

• Journal of the Society of Disaster Information
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• v.10 no.1
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• pp.71-83
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• 2014

This study carried out an experiment in order to compare thermal characteristics after collecting dust generated in the process of disposing of waste tire, plywood flour in the process of manufacturing plywood, salicylic acid dust in the process of manufacturing functional soap, and dust in the process of manufacturing wheat powder, which has potential fire and explosion hazard. According to the results of experiment, the analysis showed that all samples subject to the experiment were in the condition where heat flux decreased and temperature decreased as the quantity of added talc was increased. This shows that decomposition rate decreased, and hazard decreased. However, in all of samples subject to the experiment, as heating rate increased, endothermic onset temperature moved to the low-temperature part, and the amount of absorbed heat was largely increased. This showed that the decomposition hazard of sample increased as heating rate increased, according to the analysis. Besides, TGA experiment results showed that thermal stability was secured because total weight loss decreased as the amount of talc was increased for all samples subject to the experiment regarding the ratio of weight loss. It is expected that the continuous research and supplementation of dust explosion mechanism in the future will contribute to the establishment of measures for the effective dust explosion prevention.

• Korean Journal of Food Science and Technology
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• v.29 no.6
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• pp.1196-1201
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• 1997

As a basic study to develop low-salted fermented anchovy, rates of salt penetration into anchovy muscle, patterns of protein degradation and changes in water activity and transfer was analyzed after brining at various salt (NaCl) concentration. The salt penetration curves followed first order. kinetics. The rate constant (k) increased from 0.018 (10% NaCl solution) to 0.051 (saturated). Water activity was reduced from 0.93 (10% NaCl solution) to 0.77 (saturated). Protein degradation during brining was Somewhat occurred in 10% NaCl solution but not in satutrated solution. Water content of anchovy muscle were 74% (w/w), 65% and 58% when 10%, 20% and saturated NaCl solution were used, respectively. This result indicated that as NaCl content of brining solution was increased, the amount of water transfer also occurred. Weight of anchovy increased at 10% NaCl solution and decreased at 20% and saturated NaCl solution. The loss of anchovy solid mash during brining was calculated as 30% after 36 hr brining.

• Korean Journal of Ecology and Environment
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• v.53 no.1
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• pp.102-108
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• 2020

This study is to analyze the growth response of the Quercus dentata seedlings to four environmental factors and measure the ecological niche breadth. Environmental factors were light, moisture content, soil texture, and organic matter, treated with four gradients. The more quantity light increased, the heavier the leaves biomass, aboveground biomass, belowground biomass and plant biomass was. In treatment of water content and soil texture, growth response was no difference. The more organic matter increased, the heavier aboveground biomass was, but the remaining trait of plant was no difference. The ecological niche breadth was 0.865 in light, 0.995 in moisture content, 0.994 in soil texture and 0.988 in nutrient. Ecological niche breadth was the widest in the moisture content treatment and the narrowest in the light treatment. This means that the growth of Q. dentata seedlings grows well as the amount of light increases, and is sensitive to light, Thus, it is determined a growth and ecological niche breadth by light factors.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.1
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• pp.77-87
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• 1999

This study was performed to evaluate the effect of Streptococcus oralis on the formation of artificial plaque and the replication of Streptococcus mutans. S. mutans was incubated alone and in the combination with S. oralis in the beaker with wires. The produced plaque weight and the viable cells of S. mutans were compared between those cultures. Various factors were studied about the effect on the formation of plaque and the replication of S. mutans. Followings are the results. 1. Lower amount of plaque was produced and fewer cells of S. mutans were replicated at the mixed culture of S. mmutans and S. oralis than S. mutans alone. 2. When 10 mM glucose was added, the plaque weight was increased in the culture of S. mutans alone. But in the mixed culture of S. mutans and S. oralis, the plaque weight was not increased when 10 mM of glucose was added. 3. When 10 mM fructose was added, the plaque weight was increased in the culture of S. mutans alone or combined S. mutans and S. oralis. 4. In the mixed culture of S. mutans and S. oralis with different concentration, the more S. oralis exist, the less plaque and the fewer viable cells of S. mutans were observed. 5. The plaque weight and the viable cells of S. mutans were more decreased in the mixed culture of S. mutans and S. oralis than S. mutans alone after 12 hours. 6. When Staphylococcus epidermidis consuming hydrogen peroxide was added to the mixed culture of S. mutans and S. oralis, the plaque weight and the viable cells of S. mutans were increased. These results indicate that S. oralis inhibited the formation of plaque and the replication of S. mutans, and this may result from the formation of hydrogen peroxide S. oralis.

• Journal of the Mineralogical Society of Korea
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• v.28 no.2
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• pp.135-145
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• 2015

In order to predict the deterioration of stone monument due to acid fog, an artificial fog test using pH4.0 and pH5.6 was applied to the Gyeongju Namsan granite, decite and marble. After the test had weathered Gyeongju Namsan granite a larger weight reduction due to acid fog than fresh one. Decite has shown the most significant changes among the tested rocks with about 0.005 % of weight reduction. Decite and weathered granite will have considerable weight reduction due to acid rain than the acid fog, whereas the marble was expected to show a weight reduction regardless of the phase of water. The porosity and water absorption rate of weathered granite had significantly increased. This result means that the weathered rock is predicted to be more susceptible to acid fog than the fresh rock. The absorption rate of the marble after the test had shown approximately 50 % increase. The color of the samples had slightly changed towards yellow, such tendency was greater shown in weathered rocks. The marble reacted with acid fog had an increased whiteness. A large amount of cation in the samples is caused mainly by the dissociation of minerals through the reaction with acid fog.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.04a
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• pp.5-5
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• 1998

가스터빈 엔진은 민간 항공분야와 방위 무기의 발달과 더불어 성능이 향상되어 왔고, 그 역할도 증대하였다. 성능 향상과 역할 증대에 따라 처리하여야 할 일의 양과 그 속도가 증가하게 되면서 엔진 제어 난이도도 증가하고 제어기법도 향상되고 있다. 이에, 전자공학의 발달에 힘입어 전자식 엔진 제어기가 엔진제어의 임무를 수행하게 되었고, 근래에는 기체의 무게감소와 신뢰성 향상이라는 이중 이익을 위해 FADEC(Full Authority Digital Engine Controller)엔진 제어기까지 등장, 사용되고 있다. 가스터빈 엔진의 제어는 일반적으로 비선형 시스템에 관한 모델링 단계와 성능 해석결과를 이용한 보상기 설계 및 제어 단계의 3부분으로 크게 분류된다. FADEC이란 개념이 정착되기 이전에는 통상적인 제어 법칙인 PID(Proportional Integral Derivative) 방법이 사용되었으나, 시스템의 복잡화와 다변화에 의하여 modern control 개념이 고려된 새로운 제어 방법이 사용되기 시작하였다. 본 논문에서는 엔진 제어에 실제적으로 이용할 수 있는 제안된 제어 법칙을 이용하여 실제 엔진 모델에 적용하여 시뮬레이션 함으로써 새로운 제어 법칙이 엔진 제어에 적용 가능함을 보이고자 한다.