• Journal of Convergence for Information Technology
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• v.11 no.7
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• pp.111-117
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• 2021

This research work is to suggest the experimental results capable of solving an initial unsuitability of combustion and environment in a constant volume combustion chamber by using LFG(Land Fill Gas) which consists of 40% CO₂ and 60% CH₄. The experimental condition is set as 0.9~1.6 of air-fuel ratio, 3bar of combustion pressure, 25℃ of room temperature, methane for using gas, and 2.5~4.5 of Pre-chamber hole sizes. As a result, it can be seen that diffusion of initial flame is significantly increased by M3.0 model comparing with other one. The reason for the characteristics is that orifice effect is extremely improved by 0.9, 1.0, and 1.2 of air-fuel ratio comparing with other one. Consequently, this experiment is shown that M3.0 model is partially capable of improving combustion performance than a conventional ignition plug in case of applying to LFG with Pre-chamber design.

• Journal of Animal Environmental Science
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• v.10 no.3
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• pp.141-154
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• 2004

The solar powered water pump is very ideal equipment because solar power is more intensive when the water is more needed in summer and it is very helpful in the rural area, in which the electrical power is not available. The average so]ar radiation energy is 3.488 kWh/($m^2{\cdot}day$) in Korea. In this study, the automatic control logic and system of the water pump driven by the radiation energy were studied, designed, assembled, tested and analyzed for realizing the solar powered water pump. The experimental system was operated automatically and the cycle was continued. The average quantity of the water pumped per cycle was about 5,320 cc. The cycle time was about 4.9 minutes. The thermal efficiency of the system was about $0.030\%$. The pressure level of the n-pentane vapour in flash tank was 150$\%$450 hPa(gauge) which was set by the computer program for the control of the vapour supply. The pressure in the condenser and air tank during cycles was maintained as about 600 hPa and 1,200 hPa respectively. The water could be pumped by the amount of 128kg/($m^2{\cdot}day$) with the efficiency of $0.1\%$ and the pumping head of 10 m for the average solar energy in Korea.

• Korean Journal of Food Science and Technology
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• v.50 no.4
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• pp.407-413
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• 2018

The current study reviews the manufacturing characteristics, upon aging, using different distillation methods with Saccharomyces cerevisiae 88-4 isolated from traditional Nuruk. The alcohol content slightly decreased at 180 days of aging period, under the conditions: -60 cmHg, distilling temperature $50^{\circ}C$, head cut 7%, and body cut 30%. The alcohol content decreased by 2.2% at: -50 cmHg, distilling temperature $60^{\circ}C$, head cut 7%, and body cut 30%. From 2-thiobarbituric acid (TBA) analysis, the TBA values were not found to change significantly in most of the alcohols, but increased at conditions of: -60 cmHg, distilling temperature $60^{\circ}C$, head cut 7%, and body cut 50% and -50 cmHg, distilling temperature $50^{\circ}C$, head cut 7%, and body cut 50%, when initial alcohol levels were low. According to n-propanol, iso-butanol, and isoamyl alcohol analysis, with increasing aging period, the n-propanol and isoamyl alcohol content did not change, although that of iso-butanol decreased. The flavor components showed different results based on the aging period. Results of sensory evaluation showed no significant difference based on aging. The sensory evaluation test was continued for 180 days at a condition of: -60 cmHg, distilling temperature $60^{\circ}C$, and body cut 50%, which had the best overall evaluation ($5.8{\pm}0.9$).

• The Journal of the Petrological Society of Korea
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• v.21 no.2
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• pp.151-171
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• 2012

The Permo-Triassic Songrim orogeny in the Korean peninsula was a major tectonic event involving complicated continental collisions at the eastern margin of Eurasia. Based on the previous studies on the metamorphic and deformations features of the Songrim orogeny, this paper presents metamorphic and structural characteristics and timing of the Songrim orogeny in the Taebaeksan basin, and discuss about correlation of the tectono-metamorphic evolution of the Taebaeksan basin with the Okcheon basin and the Imjingang belt with a combined analysis of bulk crustal shortening direction, metamorphic P-T and T-t (time) paths. The metapelites in the Pyeongan Supergroup in the northeastern margin of the Taebaeksan basin have experienced lower-temperature/medium-pressure (LT/MP) regional metamorphism followed by high-temperature contact metamorphism due to the Jurassic granite intrusion. The earlier LT/MP regional metamorphism produced two loops of clockwise P-T-d (deformation) paths combined with four deformation events ($D_1-D_4$). The first loop concomitant with $D_1$ and $D_2$ occurred at $400-500^{\circ}C$, 1.5-3.0 kbar, and related with growth of syn-$D_1$ chloritoid and andalusite, post-$D_1$ margarite, Ca-rich syn-$D_2$ or post-$D_2$ plagioclase. The second loop accompanying $D_3$ and $D_4$ occurred at $520-580^{\circ}C$, 2.0-6.0 kbar, and associated with the growth of syn-$D_3$ garnet and staurolite, and syn-$D_4$ and/or post-$D_4$ andalusite porphyroblasts. Furthermore the syn-$D_1$ chloritoid and andalusite porphyroblasts grew during E-W bulk crustal shortening, whereas the syn-$D_3$ garnet and staurolite, and the syn-$D_4$ and/or post-$D_4$ andalusite porphyroblasts have grown under N-S bulk crustal shortening. The similarity in the characteristics and timing of the metamorphism and bulk crustal shortening directions between the Okcheon and Imjingang belts suggest that the peak metamorphic conditions tend to increase toward the western part (Imjingang belt and southwestern part of the Gyeonggi Massif) from the eastern part (Taebaeksan basin). The E-W bulk crustal shortening influenced the eastern part of the Okcheon belt, whereas the N-S bulk crustal shortening resulted in strong deformation in the Imjingang and Okcheon belts. Consequently, the Permo-Triassic Songrim orogeny in the Korean peninsula is probably not only related to collision of the North and South China blocks, but also to the amalgamation of terrane fragments at the eastern Eurasia margin (e.g., collision of the Sino-Korean continent and the Hida-Oki terrane).

• Sleep Medicine and Psychophysiology
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• v.13 no.1
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• pp.27-32
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• 2006

Objectives: Nasal continuous positive airway pressure (nCPAP) is the treatment of choice and has been shown to reduce the frequency of nocturnal respiratory events, improve sleep architecture, and decrease daytime sleepiness in patients with obstructive sleep apnea syndrome (OSAS). However, little is known about the compliance of nCPAP treatment in Korea. Our objective was to look into the nCPAP compliance and examine the factors influencing it. Methods: We reviewed the records of one hundred and twenty consecutive patients with OSAS referred for nocturnal polysomnography with nCPAP pressure titration during the period of January 1995 through April 1999 to the Seoul National University Hospital. We performed a telephone interview and obtained data from eighty-three patients. Results: In sixty patients who had accepted nCPAP treatment, twenty-six patients (43.3%) were still using nCPAP device, while thirty-four patients (56.7%) stopped using it. Fifteen patients (25%) were using nCPAP device everyday. In thirty-four patients who discontinued nCPAP use, twenty-five patients (73.5%) did within the first three months, and thirty-one (91.2%) within the first year. Significant predictor of long-term nCPAP use was the presence of subjective daytime sleepiness before nCPAP application. Conclusions: Long-term compliance with nCPAP treatment appears to be associated with the presence of subjective daytime sleepiness before nCPAP application. Long-term compliance with nCPAP may be mostly predicted from the usage pattern within the first three months of use.

• Journal of the Korean earth science society
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• v.22 no.4
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• pp.278-291
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• 2001

Mesothermal gold vein minerals of the Seolhwa mine were deposited in a single stage of massive quartz veins which filled the mainly NE-trending fault shear zones exclusively in the granitoid of the Gyeonggi Massif. The Seolhwa mesothermal gold mineralization is spatially associated with the Jurassic granitoid of 161 Ma. The vein quartz contains three main types of fluid inclusions at 25$^{\circ}$C: 1) low-salinity (< 5 wt.% NaCl), liquid CO$_{2}$-bearing, type IV inclusion; 2) gas-rich (> 70 vol.%), aqueous type II inclusions; 3) aqueous type I inclusions (0${\sim}$15 wt.% NaCl) containing small amounts of CO$_{2}$. The H$_{2}$O-CO$_{2}-CH$_{4}$-N$_{2}$-NaCl inclusions represent immiscible fluids trapped earlier along the solvurs curve at temperatures from 430$^{\circ}$ to 250$^{\circ}$C and pressures of 1 kbars. Detailed fluid inclusion chronologies may suggest a progressive decrease in pressure during the auriferous mineralization. The aqueous inclusion fluids represent either later fluids evelved through extensive fluid unmixing (CO$_{2}-CH$_{4}$ effervescence) from a homogeneous H$_{2}$O-CO$_{2}-CH$_{4}$-N$_{2}$-NaCl fluid due to decreases in temperature and pressure, or the influence of deep circulated meteoric waters possibly related to uplift and unloading of the mineralizing suites. The initial fluids were homogeneous containing H$_{2}$O-CO$_{2}-CH$_{4}$-N$_{2}$-NaCl components and the following properties: the initital temperature of >250$^{\circ}$ to 430$^{\circ}$C, X$_{CO}\;_{2}$ of 0.16 to 0.62, 5 to 14 mole% CH$_{4}$, 0.06 to 0.3 mole% N$_{2}$ and salinities of 0.4 to 4.9 wt.% NaCl. The T-X data for the Seolhwa gold mine may suggest that the Seolhwa auriferous hydrothermal system has been probably originated from adjacent granitic melt which facilitated the CH$_{4}$ formation and resulted in a reduced fluid state evidenced by the predominance of pyrrhotite. The dominance of negative ${\delta}\;^{34}$S values of sulfides (-0.6 to 1.4$%_o$o) are consistent with their deep igneous source.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.7
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• pp.935-939
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• 2006

Raw oyster (Crassostrea gigas) was inoculated with Vibrio parahaemolyticus and Escherichia coli, treated with high hydrostatic pressure and evaluated for microbial counts. Cell death of V. parahaemolyticus (Vp) increased with the increase of applied pressure. Vp starting inoculum of $3.8{\times}10^5\;CFU/mL$ was totally eliminated after exposure to 200 MPa for 10 min at $22^{\circ}C$ Viable cell of Vp decreased with the increase in treatment time and dropped below the detection limit with treament of 25 min at $22^{\circ}C/150\;MPa$. The number of Vp by treatment of $0^{\circ}C$ and $10^{\circ}C$ for 20 and 25 mon at 100 MPa, respectively. For E. coli, there was an initial lag up to 250 MPa gollowed by a rapid decline. Treatment at 325 MPa/$22^{\circ}C$ for 15 min caused 5-log reduction, while that at 375 MPa resulted in total reduction of starting inoculum of $4.0{\times}10^7\;CFU/mL$. Lower treatment temperature showed higher killing effect of E. coli at the same treatment pressure and time. Viable cell of E. coli decreased with the increase in treatment time, and 4-log reduction was achieved with treatment of 5 min at $10^{\circ}C$/350 MPa and then total reduction was achieved after treatment of 15 mon. Higher pressure, lower temperature and longer time were more effective in sterilizing V. parahaemolyticus and E. coli.

• Journal of Korean Society of Forest Science
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• v.37 no.1
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• pp.17-30
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• 1978

Press drying was used on italian poplar (Populus euamericana) to find the profitable means of drying. This study was designed to investigate the process of platen drying considering core temperature, drying time, current moisture content, drying rate, shrinkage and recovery, and green volume specific gravity, equilibrium moisture content and dimensional stability of press dried material and air dried material, The drying tests were conducted using 1.5 centimeter thick material at platen temperature of $175^{\circ}C$. The results were summarized as follows. 1. Core temperature was divided into three stages of drying characterized by period initial heating, plateau temperature and rising core temperature. Plateau temperature was 114 to $119^{\circ}C$. 2. The following predicting equations of drying time(y) in different core temperatures were developed for initial thickness($x_1$), initial moisture content ($x_2$) and final moisture content ($x_3$) 3. The predicting equaltion of current moisture content(u) was log u=4.658-0.060t as funtion of drying time(t) and that of drying rate(r) was log r=-2.797-0.049t. Current moisture content and drying rate of air drying were shown in figure 2. 4. The predicting equation of shrinkage in thickness direction(y) was log y=1.933+0.038t as function of drying time(t), and that of expansion in width direction was $y=-0.692+0.043t-0.001t^2$. 5. Thickness shrinkage was increased more than proportional at to pressure increase. Width shrinkage and thickness recovery was greatest at 35psi. 6. Green volume specific gravity of press dried material was 25% greater than that of air dried material. But equilibrium moisture content of press dried material was less 24% than that of air dried material. Antishrinkage efficiency of press dried material were obtained 27.7%.

• Journal of Soil and Groundwater Environment
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• v.13 no.5
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• pp.81-87
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• 2008

In accompany with the transfer of US army bases, recent surveys reported serious contamination of soils by the release of petroleum from storage facilities and heavy metals accumulated in rifle-ranges. These problems have made an increased concerns of cleanup technology for contaminated soils. In this study, a full-scale soil washing process improved by multistage continuous desorption and agitational desorption techniques was examined for petroleum-contaminated soils obtained from three different remedial sites that contained 29.3, 16.6, and 7.8% of silt and clay, respectively. The initial concentrations of total petroleum hydrocarbon (TPH) were 5,183, 2,560, and 4,860 mg/kg for each soil. Pure water was applied to operate washing process, in which water used for washing process was recycled 100% for over 6 months. The results of full-scale washing tests showed that the TPH concentrations for soils (> 3.0 mm) were 50${\sim}$356 mg/kg (85.2${\sim}$98.2% removal rates), regardless of the contents of silt and clay from in A, B and C soil, when the soils were washed at 3.0 kg/$cm^2$ of injection pressure with the method of wet particle separation. Based on the initial TPH concentration, the TPH removal rates for each site were 85.2, 98.2 and 89.9%. For soils in the range of 3.0${\sim}$0.075 mm, the application of first-stage desorption technique as a physical method resulted 834, 1,110, and 1,460 mg/kg of TPH concentrations for each soil, also additional multi-stage continuous desorption reduced the TPH concentration to 330, 385, and 245 mg/kg that were equivalent to 92.4, 90.6, and 90.1% removal rates, respectively. The result of multi-stage continuous desorption for fine soil (0.075${\sim}$0.053 mm) were 791, 885, and 1,560 mg/kg, and additional agitation desorption showed 428, 440, and, 358 mg/kg of TPH concentrations. Compared with initial concentration, the removal rates were 92.0, 93.9 and 92.9%, respectively. These results implied we could apply strategic process of soil washing for varies types of contaminated soils to meet the regulatory limit of TPH.

• The Journal of the Petrological Society of Korea
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• v.10 no.2
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• pp.57-81
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• 2001

In the amphibolites of the Hwanggangri area, three metamorphic zones are established like hornblende-actinolite zone (H-AZ), hornblende zone (HZ) and diopside zone (DZ) by the main mineral assemblages. Hornblende zone and hornblende-actinolite zone develope away from the diopside zone that experienced the highest thermal effect. Thus, this pattern identifies the decreasing metamorphic grade of the contact metamorphism with increasing distance from the granitic pluton. The mineral assemblages of this rock are classified into six representative groups such as $\circled1$ actinolite+plagioclase+chlorite, $\circled2$ actinolite+hornblende+plagioclase+chlorite$\pm$epidote$\pm$biotite, $\circled3$ actinolite+hornblende+plagioclass$\pm$biotite$\pm$epidote, $\circled4$ hornblende+plagioclase$\pm$biotite$\pm$chlorite, $\circled5$ hornblende+plagioclase+diopside+actinolite$\pm$epidote$\pm$chlorite, $\circled6$hornblende+plagioclase+diopside$\pm$biotite$\pm$epidote. Two metamorphic events m recognized in the amphibolites of the study area that the first metamorphism is the regional metamorphism dominantly occurred in the whole Ogcheon metamorphic belt and it gave rise to the growth of actinolite at the core or center of the amphibole grains of coarse and medium size. Its metamorphic grade ranges from the greenschist facies to epidote-amphibolite facies. The second metamorphism overlapped is the contact metamorphism caused by the adjacent granitic pluton, and its metamorphic grade is thought to reach to the low pressure part of upper amphibolite facies. According to the calculation by TWEEQU thermobarometry and amphibole-plagioclase thermometry, the metamorphic temperature of initial regional metamorphism is $439-537^{\circ}C$ under pressure of 4.6-7.3 kb and its peak temperature and pressure are considered to reach to the range of 492-537 and 5.2-7.3 kb. And the temperature range of contact metamorphism occurred by intrusion of cretaceous granitic body, is $588-739^{\circ}C$ under pressure of 2.6-5.2 kb and its peak temperature and pressure are estimated as having the range of $697-739^{\circ}C$ and 3.8-5.2 kb that this amphibolites are estimated to pass through the metamorphic evolution of both the rise of temperature and the drop of pressure.