• Electrical & Electronic Materials
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• v.3 no.2
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• pp.115-122
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• 1990

플라즈마중합 에틸메타아크릴레이트(PPMMA) 박막의 유전특성인 유전정접(tan .delta.)과 정전용량(C)을 관측하고 산화와 열처리 및 플라즈마처리로 인한 PPMMA의 tan .delta.와 C의 변화에 대하여 연구하였다. 측정온도 25.deg.C, 측정주파수 1KHz에서 1MHz의 범위에서 PPMMA 박막은 CO와 -OH같은 산화물의 생성으로 인하여 tan .delta. 와 C는 증가하고 tan .delta.는 측정주파수 내에서 피이크를 형성한다. 이는 PPMMA내에 잔류하는 저분자량 성분과 자유라디칼의 존재와 공기중에서의 산화가 그 원인이라 할 수 있다. 본연구에서는 PPMMA박마그이 열처리 및 플라즈마처리를 하여 저분자량 성분과 라디칼을 제거하고 산화를 방지하여 박막의 유전특성을 개선하였다.

• Journal of the Korean Applied Science and Technology
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• v.33 no.2
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• pp.264-270
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• 2016

This Study is to into fuel using a torrefation reaction to food waste. When the fuel of only food waste alone, fuel value is was performed at a ratio of sewage sludge constant attempts to prevent low. Mixing ratios of food waste and sewage sludge, 10:0, 8:2, 6:4, 5:5. Regardless mixing ratio, it was possible to confirm that decreases the moisture content of 10% or less at a reaction temperature of $240^{\circ}C$ or higher. As the ratio of the reaction temperature and the sewage sludge is high, the fixed carbon content is increased. It was measured at up to 36%(mixing ratios6:4, reaction temperature $270^{\circ}C$) from the initial 1.1%. From the reaction temperature $240^{\circ}C$ satisfied with 3000Kcal/Kg or more is a SRF criteria shows the calorific value. It was possible to obtain a heating value that is increased from the raw sample approximately sextuple. As reaction temperature is heightened, Van krevelen Diagram moved to the range of Lignite range. It was possible to obtain high fuel ratio and 5,500Kcal/kg or less of a combustility index as the sewage sludge mixing ratio becomes high. Increase the fixed carbon content, than those food waste alone solid fuel into and improved fuel costs, it is necessary to ensure that the quality of the fuel is improved.

• Journal of the Korean Magnetics Society
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• v.17 no.2
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• pp.65-70
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• 2007

In this paper, we composed the $LiFePO_4$ for the reversible use as the replacement material of the Li ion batteries and confirmed the good quality of the structure of the samples with the sintering temperature $675^{\circ}C,\;750^{\circ}C,\;and\;800^{\circ}C$ for 30 hours at nitrogen atmosphere. We also investigated the size of the particles through SEM picture and the change of the sintering temperature and the $Fe^{+3}$ content after charging the materials with 1 V, 160 mA and 3 V, 40 mA for 3 hours by Mossbauer spectroscopy. Also we can observe the increase on the $Fe^{+3}$ content at the charge condition and the increase of the amount ratio of the $Fe^{+3}$ ion only in sintering temperature $675^{\circ}C$ according to the increase of the electric charge. We cannot observe the change of the $Fe^{+3}$ ion in sintering temperature $800^{\circ}C$ after charging.

• Korean Journal of Organic Agriculture
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• v.15 no.4
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• pp.413-424
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• 2007

This trial was carried out to determine effects of TMR(Total Mixed Ration) in comparison to conventional diet on feed intake, digestibility, and nitrogen retention in Korean black goats. Twelve Korean black goats were allotted to treatments in four groups of three goats and the they were housed in separate metabolism cages for 21 days. Treatments included conventional diet(A: rice straw and commercial concentrates) as a control group and three TMR groups(B: rice straw and commercial TMR; C: 30% organic whole barley silage and rice straw with organic grain; D: 60% organic whole barley silage with organic grain). The results obtained are summarized as follows. Dry matter intake, fecal excreta, digestible dry matter, metabolic intake and feed intake of BW were significantly higher(p<0.05) compared with A, B, C treatment. The digestibility for most of nutrients except NFC was significantly higher(p<0.05) for D treatment than the others. On the other hand, the digestibility of NFC was higher for B treatment than for the others, even if it was not significantly different across treatments. Nitrogen intake was lower for D treatment, but the significant differences were not found across treatments. N retention rate was higher for B treatment with significant difference. For the blood composition, HDL cholesterol and Immunoglobulin G were significantly higher(p<0.05) for C, D treatment than the others. The results showed that, in comparison with A treatment(conventional diet) and B treatment(commercial TMR), dry matter intake, nutrient digestibility and N retention rate were not lower in C treatment(30% organic whole barley silage) and HDL cholesterol was increased after experiment. Therefore, it could be concluded that TMR with organic whole barley silage might contribute to the production of a high quality and safer meat in goat production.

• Korean Journal of Environment and Ecology
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• v.32 no.4
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• pp.413-424
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• 2018

The study analyzed the effects of topographic structures and altitude in mountainous parks in Mt. Namsan in Gyeongju on the generation of anions. The temperature was at ridge ($9.82^{\circ}C$) > valley ($8.44^{\circ}C$), the relative humidity valley (59.01 %) > ridge (58.64 %), the solar radiation ridge ($34.40W/m^2$) > valley($14.69W/m^2$), the wind speed ridge (0.63m/s) > valley(0.37m/s), and the negative ion valley($636.81ea/cm^3$) > ridge($580.04ea/cm^3$). In the valley, the correlation with altitude was verified for the temperature, relative humidity, solar radiation, and negative ion generation in the valley. The relative humidity, solar radiation, and negative ion indicated a positive correlation while the temperature had a negative correlation. In the ridge, the correlation with altitude was verified for the temperature, relative humidity, wind speed, solar radiation, and negative ion generation. The relative humidity, solar radiation, and negative ion generation indicated a positive correlation while the temperature and wind speed had a negative correlation. The regression analysis showed the prediction equation of y=-0.006x+9.663 (x=altitude, y=temperature) in the valley and y=-0.009x+11.595 (x=altitude, y=temperature) in the ridge for the temperature, y=0.027x+53.561 (x=altitude, y=relative humidity) in the valley and y=0.008x+56.646 (x=altitude, y=relative humidity) in the ridges for the relative humidity, and y=0.027x+53.561 (x=altitude, y=negative Ion generation) in the valley and y= 0.008x+56.646 (x=altitude, y=negative Ion generation) in the ridge for the negative ion generation.

• Microbiology and Biotechnology Letters
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• v.35 no.3
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• pp.203-209
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• 2007

Soybean milk cake (SMC) was used for the solid-state fermentation by Bacillus subtilis PUL-A isolated from soybean milk cake. In the presence of 5% glutamate the maximum production of biopolymer (59.9 g/kg) was performed by fermentation at $42^{\circ}C$ for 24 hr. The recovered biopolymer was consisted of 87% $\gamma$-polyglutamic acid with molecular weight of $1.3{\times}10^6$ dalton and other biopolymer. The biopolymer solution showed the great decrease in consistency below pH 6.0, regardless of the molecular weight of PGA. Biopolymer solution has a typical pseudoplastic flow behavior and yield stress. The consistency of biopolymer solution was greatly decreased by increasing heating time and temperature in acidic condition compared to the alkaline condition. In kaolin clay suspension, the flocculating activity of biopolymer was the highest value with 15 mg/L biopolymer and 4.5 mM $CaCl_2$, but decreased greatly with $FeCl_3$. The flocculating activity of biopolymer was maximum at pH5, but decreased drastically by heating at $60{\sim}100^{\circ}C$. In particular, biopolymer with native PGA showed the efficient flocculating activity compared to that of modified biopolymer containing low molecular weight of PGA.

• Journal of the Korean Magnetics Society
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• v.11 no.3
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• pp.114-121
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• 2001

Effect of sintering temperature and dusts content on sintered density ($\rho$) and magnetic properties were evaluated. Cores sintered at 1350 $^{\circ}C$ for 1 hour with the Fe powders containing up to 10 wt.% dusts showed a good AC/DC properties. For example, the DC magnetic properties of magnetic induction (B$_{15}$), coercive force (H$_{c}$) and permeability ($\mu$$_{max}$) of cores containing 10 wt.% dusts were ranging over 9.8~ 10.9 kG, 2.2-2.3 Oe and 1950~2050, respectively. These magnetic properties are equivalent to those of competitor's (i.e, Ancorsteel produced by Hoganas). The cores obtained from the present work are expected to apply for high-performance soft magnetic components such as automotive and DC motor.

• Journal of Life Science
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• v.17 no.12
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• pp.1689-1694
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• 2007

This study was conducted to investigate both fat-soluble and water-soluble vitamin contents of commercial powdered infant formula for obtaining basic data on infant nutrition. Ten commercial infant formula based on cow's milk were collected and the contents of fat-soluble vitamins (vitamin A, D, E, K) and water-soluble vitamins (vitamin C, thiamin, riboflavin, niacin, $B_6$, folate, $B_{12}$, pantothenic acid, biotin) were compared with Dietary Reference Intakes for Koreans (KDRIs). The overall vitamin contents in 100 g and in 100 kcal of infant formula satisfied the recommended formula regulation (KDRIs) and Codex. In infant formula during 0-5 monthly age, fat-soluble vitamin A, D, E, K could supply 178.6%, 205.3%, 208.4%, 976.3% of adequate daily vitamin intakes, respectively. Water soluble vitamins, vitamin C, thiamin, riboflavin, niacin, $B_6$, folate, $B_{12}$, pantothenic acid, biotin could supply 173.2%, 237.2%, 269.8%, 295.9%, 431.6%, 165.8%, 1186.3%, 203.8%, 408.3% of adequate daily vitamin intakes, respectively. In infant formula during 6-11 monthly age, all vitamins satisfied their adequate daily intakes as well. Vitamin A, D, E, K supplied 199.2%, 262.3%, 220.5%, 626.46% of adequate daily vitamin intakes. Vitamin C, thiamin, riboflavin, niacin, $B_6$, folate, $B_{12}$, pantothenic acid, biotin could supply 179.5%, 210.2%, 264.7%, 241.5%, 206.0%, 166.9%, 699.5%, 247.0%, 475.0% of adequate intake of KDRIs. From this study, evaluation of vitamin contents of commercial infant formula was established, which could strengthen the basic information on infant nutrition.

• Journal of Bio-Environment Control
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• v.28 no.3
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• pp.204-211
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• 2019

The purpose of this study is to provide basic data for setting environmental design standards for domestic greenhouses. We conducted experiments on thermal environment measurement at two commercial greenhouses where hot water heating system is adopted. We analyzed heat transfer characteristics of hot water heating pipes and heat emission per unit length of heating pipes was presented. The average air temperature in two greenhouses was controlled to $16.3^{\circ}C$ and $14.6^{\circ}C$ during the experiment, respectively. The average water temperature in heating pipes was $52.3^{\circ}C$ and $45.0^{\circ}C$, respectively. Experimental results showed that natural convection heat transfer coefficient of heating pipe surface was in the range of $5.71{\sim}7.49W/m^2^{\circ}C$. When the flow rate in heating pipe was 0.5m/s or more, temperature difference between hot water and pipe surface was not large. Based on this, overall heat transfer coefficient of heating pipe was derived as form of laminar natural convection heat transfer coefficient in the horizontal cylinder. By modifying the equation of overall heat transfer coefficient, a formula for calculating the heat emission per unit length of hot water heating pipe was developed, which uses pipe size and temperature difference between hot water and indoor air as input variables. The results of this study were compared with domestic and foreign data, and it was found to be closest to JGHA data. The data of NAAS, BALLS and ASHRAE were judged to be too large. Therefore, in order to set up environmental design standards for domestic greenhouses, it is necessary to fully examine those data through further experiments.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.2
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• pp.203-210
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• 2010

The signification of calorie/water (C/W) ratio was investigated in the treatment of highly concentrated organic wastes by thermophilic oxic process (TOP). Swine waste was used in this study. When C/W ratio was 1.6, most of swine waste was decomposed and all water was evaporated in the 24-h injection cycle. To improve treatment efficiency of TOP treating swine waste, the effect of shortening the swine waste injection cycle was examined. The shortening of injection cycle was conducted to stimulate the activity of thermophilic bacteria. A high temperature in the reactor was maintained by shortening of the injection cycle. When the swine waste injection cycle was shortened, the C/W ratio was fixed at 1.6. As a result, by shortening the swine waste injection cycle from 24-h to 12 and 6-h, the maximum loading rate of swine waste per day could be improved 1.9 and 3.5 times, respectively.