• Korean Journal of Materials Research
• /
• v.9 no.12
• /
• pp.1211-1215
• /
• 1999

Fluorinated amorphous carbon (a-C:F) films were prepared by an electron cyclotron resonance chemical vapor deposition (ECRCVD) system using a gas mixture of $C_2F_6$ and $CH_4$ over a range of deposition temperature (room temperature ~ 300$^{\circ}C$). 500$^{\AA}C$ thick DLC films were pre-deposited on Si substrate to improve the strength between substrate and a-C:F film. The chemical bonding structure, chemical composition, surface roughness and dielectric constant of a-C:F films deposited by varying the deposition temperature were studied with a variety of techniques, such as Fourier transform infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy(XPS), atomic force microscopy (AFM) and capacitance-voltage(C-V) measurement. Both deposition rate and fluorine content decreased linearly with increasing deposition temperature. As the deposition temperature increased from room temperature to 300$^{\circ}C$, the fluorine concentration decreased from 53.9at.% down to 41.0at.%. The dielectric constant increased from 2.45 to 2.71 with increasing the deposition temperature from room temperature to 300$^{\circ}C$. The film shrinkage was reduced with increasing deposition temperature. This results ascribed by the increased crosslinking in the films at the higher deposition temperature.

• Applied Chemistry for Engineering
• /
• v.16 no.6
• /
• pp.737-741
• /
• 2005

In this study, the effect of copper content on the NO removal efficiency by Cu/MCM-41 has been investigated. MCM-41 was prepared by hydrothermal synthesis using a gel mixture of colloidal silica solution and cetyltrimethylammonium. Cu/MCM-41 was manufactured with copper content (5, 10, 20, and 40%) in Cu(II) acetylacetonate. The surface properties of MCM-41 were investigated by using pH, XRD, and FT-IR analyses. $N_2/77K$ adsorption isotherm characteristics, including the specific surface area and micropore volume were studied by BET's equation and Boer's t-plot methods. NO removal efficiency was confirmed by gas chromatography technique. From the experimental results, the MCM-41 was analyzed to have the surface functional groups of Si-OH and Si-O-Si and the characteristic diffraction lines (100), (110), (200), and (210) corresponding to a hexagonal arrangement structure. The copper content supported on MCM-41 appeared to increase the NO removal efficiency in spite of decreasing the specific surface areas or micropore volumes. Consequently, it was found that the copper content in Cu/MCM-41 played an important role in improving the NO removal efficiency, which was mainly attributed to the catalytic reactions.

• Journal of Animal Environmental Science
• /
• v.16 no.1
• /
• pp.51-60
• /
• 2010

This experiment was conducted to investigate the effects of concentrated pig slurry separated from membrane filter and by environment-friendly agro-materials mixtures on growth of lettuce in hydroponics. The swine waste treatment system having a ultra filtration and a reverse osmosis process was designed in this study. Filtration of pig slurry was necessary to prevent the hose clogging in hydroponics. Primary separation using ultra filter was followed by concentration by RO (Reverse Osmosis). The concentrated pig slurry (CS) was mixed by five different environment-friendly agro-materials mixtures. The chemical nutrient solution was the solution of National Horticulture Research Station for the growth of lettuce. The concentration of nutrient solution in hydroponics was adjusted a range of 1.5 mS/cm in EC. The concentrated pig slurry was low in phosphorus(P), suspended solid and heavy matal, but rich in potassium (K). The concentrated slurry was lowest in the growth characteristics of leaf lettuce. And also SPAD value in leaf was reduced in plot treated with concentrated slurry. But the growth of lettuce in the mixtures plot (CS+BM+AA, CS+BM+AA+SW) in hydroponics was significantly high compared to concentrated slurry. The fresh yield of lettuce was 78, 84% that of nutrient solution as 131.9, 142.2g in plot of CS+BM+AA and CS+BM+AA+SW, respectively. Our studies have shown that it is possible to produce organic culture using concentrated slurry and environment-friendly agro-materials mixture, although growth is slower than when using a conventional inorganic hydroponic solution.

• The Korean Journal of Food And Nutrition
• /
• v.17 no.4
• /
• pp.374-381
• /
• 2004

This study was performed to characterize the mechanism of the acceleration of lactic acid fermentation in milk incubated with potato flour irradiated by ${\gamma}$-ray and two types of lactobacillus, Lactobacillus bulgaricus and Streptococcus thermophillus, and to examine its effect on the quality of yogurt by assessing the acidity of lactic acid, viscosity, free amino acid, and sensory. In lactic acid fermented in the presence of 0.5% (w/w) potato flour, its acidity was higher, its pH was lower, and its viscosity was increased than lactic acid fermented in the absence of potato flour. In the sample fermented with the mixture of S. thermophillus and L. bulgaricus, the acid production rate was highest. In the samples fermented with a single type of bacteria, the acid production rate of S. thermophillus was higher than that the L. bulgaricus. Fermented a single type of bacteria with potato flour, the lysine utilization rate of L. bulgaricus and S. thermophillus was high. L. bulgaricus produced a large quantity of glutamic acid whereas S. thermophillus consumed glutamic acid. In sensory evaluation of yogurt fermented with potato flour, the preference of texture was improved while its color, taste, flavor, and overall preference were decreased. The data suggest that L. bulgaricus stimulates the growth of S. thermophillus by providing free glutamic acid that is required by S. thermophillus and thus the addition of potato flour shortens the fermentation period of yogurt.

• Fire Science and Engineering
• /
• v.32 no.3
• /
• pp.42-50
• /
• 2018

The effect of sub-grid turbulence and combustion models on the mean flame height in a heptane pool fire according to the Fire Dynamics Simulator (FDS) version (5 and 6) based on Large Eddy Simulation (LES) was examined. The heat release rate for the fire simulation was provided through experiments performed under identical conditions and the predictive performance of the mean flame height according to FDS version was evaluated by a comparison with the existing correlation. As a result, the Smagorinsky and Deardorff turbulence models applied to FDS 5 and 6, respectively, had no significant effects on the mean flow field, flame shape and flame height. On the other hand, the difference in pool fire characteristics including the mean flame height was due mainly to the difference in the mixture fraction and Eddy Dissipation Concept (EDC) combustion models applied to FDS 5 and 6, respectively. Finally, compared to FDS 6, FDS 5 provided the predictive result of a significantly longer flame height and more consistent mean flame height than the existing correlation.

• Korean Journal of Food Science and Technology
• /
• v.32 no.6
• /
• pp.1358-1364
• /
• 2000

A mixed culture of bacteriocin-producing lactic acid bacteria and yeast was used to prepare unique fermented fruit and vegetable beverage which contains bacteriocin. Fruit and vegetable broth fermented by Lactococcus lactis 11454 showed inhibitory activity against foodborne pathogens such as Listeria monocytogens and Staphylococcus aureus, and Streptococcus mutans which is a major causative agent for dental caries. Bacteriocin was detected at the end of fermentation of fruit and vegetables and its antimicrobial activity was stable for 5 weeks during storage at $4^{\circ}C$. These results suggest that the presence of bacteriocin in beverages during fermentation and storage will provide a safeguard against foodborne pathogens and spoilage bacteria. To improve flavor of the fermented broth, post-fermentation of the fermented broth was carried out at $4^{\circ}C$ by using yeast isolated from raw material mixture. Total acidity of the post-fermented broth was slightly decreased, but significant increase in the concentration of succinic acid was observed in the post-fermented broth. It was also observed that bitter and disagreeable taste compounds such as phthalates were decreased, and mild acidic and fruity flavor esters and alcohols were increased by the post-fermentation of the fermented broth with yeast.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.33 no.5
• /
• pp.899-904
• /
• 2004

The objectives of the experiment were to examine the effects of extrusion process variables on the yield of extruded ginseng extract and to determine the effect of ratio of extruded ginseng extract and microcrystalline cellulose on characteristics of spheronized granules by cold extrusion-spheronization process. Extrusion process variables observed were feed moisture (15, 22, 29%), die temperature (90 110 13$0^{\circ}C$) and screw speed (150 200, 250 rpm). The results showed that moisture content of dried ginseng significantly affected extraction yield (P<0.05). The less moisture content of the feed resulted in the higher yield of the extract. Moisture content of 15%, screw speed of 250 rpm and die temperature of 13$0^{\circ}C$ gave the highest yield of ginseng extract. Mean extraction yield of extruded ginseng using hot water extraction was greatly improved by extrusion process The extract yield of extruded ginseng was 43.5% which was higher than that of red ginseng (38.3%) and white ginseng (29.0%) produced by traditional process. It was possible to make from the mixture of microcrystalline cellulose (200 g) mixed with different concentration of 200 mL solution (0, 5, 20, 30 40 50 60% of ginseng extract with 59.2% dry solid) by using cold extrusion spheronization. When the concentration of ginseng extract Increased, the granulation yield was improved but friability and compression index were reduced. Ginseng extract such as saponin was completely released from spheronized granules in distilled water within 10 min. It can be concluded that spheroniged granule with ginseng extract could be packed in gelatin capsule since granules Possessed proper physical properties and quick release of saponin.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.5
• /
• pp.853-859
• /
• 2007

This paper presents a microstrip patch array antenna having transmission feed and reception feed for satellite communication in the Ku band. In this paper, the element of the patch array antenna is a three-stacked structure consisting of one radiation patch and two parasitic patches for high gain and wide bandwidth characteristics. To obtain higher gain, the unit elements are expanded into a $1{\times}8$ may using a mixture of series and parallel feeds. The proposed antenna has horizontal polarization for the Rx band and vertical polarization for the Tx band. To verify the practicality of this antenna, we fabricated a three-stacked patch array antenna and measured its performance. The gain of the array antenna in the Rx and Tx bands exceeds 17 and 18 dBi, respectively. The impedance bandwidth is over 10 % in both bands. The cross-polarization level is below -25 dB, and the sidelobe level is below -9.4 dB.

• Asian Journal of Turfgrass Science
• /
• v.23 no.2
• /
• pp.287-294
• /
• 2009

This study conducted to evaluate the growth characteristics of creeping bentgrass in summer after application of the plant growth regulator, Trinecapac-ethyl, and these data may provide basic information to golf course turf maintenance. The results showed that the shoot density of creeping bentgrass was increased an average density of 1.7 $ea/cm^2$ with the trinexapac-ethyl application, especially about 2 $ea/cm^2$ during the growth retarded period of June and July. The root length increased also in June and August. The visual quality was improved significantly with trinexapac-ethyl treatment all the experimental periods, moreover, the effect was significant by reducing a summer decline stress of creeping bentgrass during the warm and humid period of summer. The green speed was significantly improved by this growth regulator treatment and those effect was prominent during stressed season of late June to mid July. Overall of the result, we found that shoot density, visual quality and green speed of bentgrass green were improved by trinexapac-ethyl treated from early growing season of spring and these effects were continued during summer. It should be very beneficial to manage the bentgrass green in stressed season. In future, the possibility and efficiency of mixture with fungicides and/or fertilizers might be needed. The spring green-up test with trinexapac-ethyl will be followed in next spring.

• Food Science and Preservation
• /
• v.18 no.6
• /
• pp.907-915
• /
• 2011

Moju is a low-alcoholic beverage made by filtering after boiling a mixture of makgeolli, ginseng, arrowroot, licorice root, cinnamon, jujube, ginger, and raw sugar. It is known to alleviate hangovers. To provide information for use in the development of palatable Moju, this study evaluated the physicochemical and sensory properties of 22 kinds of Moju being sold at different restaurants in Jeonju city. The mean values of obtained in the physicochemical analysis were as follows: water content, 91.28%; alcohol content, 1.09%; pH, 4.25; total acidity, 0.27%; reducing sugar content, 40.68 mg/mL; soluble solid content, 13.75 $^{\circ}Brix$; and viscosity 11.19 cP. The Lactic-, malic-, and citric- acid contents were higher than the contents of other organic acids. The sucrose content was higher than the contents of other free sugars. The mean value of the free amino acids was 175.3 mg%, lower than that of Takju, the main ingredient of Moju. It was considered that the free amino acids in Takju can be used as a substrate for the browning reaction in the process of Moju manufacture. In the sensory evaluation, the Moju with 0.15~0.25% total acidity, 10.6~13.4 $^{\circ}Brix$, and 5.73~9.57 cP was preferred.