• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.4
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• pp.383-387
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• 2013

This study was carried out to examine whether the leaf size is likely to be used as a selection criterion for large seed genotype in soybean (Glycine. max (L.) Merr.) breeding program. Two hundred twenty nine soybean germplasms which had collected in Korea, United States, China and Japan were used in this experiment. The area of unifoliate leaf, middle leaflet of first trifoliate and third trifoliate leaf ranged from $3.2cm^2$ to $33.8cm^2$, 9.2 to $29.5cm^2$, and 7.2 to $58.9cm^2$, respectively. One hundred seed weight also showed great variation from 2.7 to 39.0 gram. The average leaf area of unifoliate, middle leaflet of first trifoliate and third trifoliate leaf were $15.7cm^2$, $18.1cm^2$ and $32.7cm^2$, respectively, and that of seed average weight was 17.2 gram per one hundred seed. Significantly positive correlations were observed between seed weight and leaf area of unifoliate (r=$0.80^{**}$), first trifoliate (r=$0.75^{**}$) and third trifoliate (r=$0.67^{**}$), respectively. Both the leaf length and leaf width of unifoliate, middle leaflet of first trifoliate and third trifoliate leaf were significantly positively correlated with seed weight and both the correlations of unifoliate were higher than the other leaves. The correlations of leaf width in soybean leaflet were higher than those of leaf length. Leaf length/width (L/W) ratio of upper leaf was higher than that of lower leaf in the leaf size. Both the leaf area and leaf width of unifoliate leaf are the most suitable predictive characteristics of early selection in related to seed weight for soybean breeding program.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.1
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• pp.1-7
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• 2011

Purpose: The purpose of this study was to investigate the cutting efficiency of coarse grit diamond burs with air-turbine handpiece on natural tooth. Materials and methods: Four groups of coarse grit diamond bur were selected: Komet (A), Shofu (B), Premier (C), and Mani (D). The extracted maxillary central incisors were used, and ten cuts were made on each specimen, using the rotary diamond burs. The surface of each bur was measured at the upper, middle, and bottom of the bur with confocal laser scanning microscope and imaged with SEM. The data were analyzed with one-way ANOVA and t-test at the significance level of 0.05. Results: The surface roughness was measured. At the A diamond bur, the Sa values were $52.93\;{\mu}m$, $48.32\;{\mu}m$, $46.79\;{\mu}m$, $45.06\;{\mu}m$, and $43.43\;{\mu}m$ for control, test 1, 2, 3, and 4 respectively. The Sa values were $50.68\;{\mu}m$, $45.62\;{\mu}m$, $44.41\;{\mu}m$, $44.10\;{\mu}m$, and $42.46\;{\mu}m$ for B diamond bur, $58.02\;{\mu}m$, $55.53\;{\mu}m$, $52.22\;{\mu}m$, $48.26\;{\mu}m$, and $45.36\;{\mu}m$ for C diamond bur, and $50.11\;{\mu}m$, $46.73\;{\mu}m$, $45.46\;{\mu}m$, $42.58\;{\mu}m$, and $41.80\;{\mu}m$ for D diamond bur. Surface roughness after each bur use showed significant changes, but no significant difference was found in surface roughness change between bur systems. Conclusions: Surface roughness in the same bur system showed significant differences after each tooth preparation. However no statistically significant differences were found in surface roughness between bur systems. The SEM images between control and test 4 showed the abraded particles.

• The Journal of Engineering Geology
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• v.21 no.2
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• pp.163-178
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• 2011

A test borehole was drilled in the Cheongwon area to investigate the relationship between geochemical environment and the natural occurrence of radioactive materials (uranium and Rn-222) in borehole groundwater. The borehole encountered mainly biotite schist and biotite granite, with minor porphyritic granite and basic dykes. Six groundwater samples were collected at different depths in the borehole using the double-packed system. The groundwater pH ranges from 5.66 to 8.34, and the chemical type of the groundwater is Ca-$HCO_3$. The contents of uranium and Rn-222 in the groundwater are 0.03-683 ppb and 1,290-7,600 pCi/L, respectively. The contents of uranium and thorium in the rocks within the borehole are 0.51-23.4 ppm and 0.89-62.6 ppm, respectively. Microscope observations of the rock core and analyses by electron probe microanalyzer (EPMA) show that most of the radioactive elements occur in the biotite schist, within accessory minerals such as monazite and limenite in biotite, and in feldspar and quartz. The high uranium content of groundwater at depths of -50 to -70 m is due to groundwater chemistry (weakly alkaline pH, an oxidizing environment, and high concentrations of bicarbonate). The origin of Rn-222 could be determined by analyzing noble gas isotopes (e.g., $^3He/^4He$ and $^4He/^{20}Ne$).

• Journal of Korea Water Resources Association
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• v.53 no.9
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• pp.661-670
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• 2020

The water supply system has a wider installation range and various components of it than other infrastructure, making it difficult to secure stability against earthquakes. Therefore, it is necessary to develop methods for evaluating the seismic performance of water supply systems. Ground Motion Prediction Equation (GMPE) is used to evaluate the seismic performance (e.g, failure probability) for water supply facilities such as pump, water tank, and pipes. GMPE is calculated considering the independent variables such as the magnitude of the earthquake and the ground motion such as PGV (Peak Ground Velocity) and PGA (Peak Ground Acceleration). Since the large magnitude earthquake data has not accumulated much to date in Korea, this study tried to select a suitable GMPE for the domestic earthquake simulation by using the earthquake data measured in Korea. To this end, GMPE formula is calculated based on the existing domestic earthquake and presented the results. In the future, it is expected that the evaluation will be more appropriate if the determined GMPE is used when evaluating the seismic performance of domestic waterworks. Appropriate GMPE can be directly used to evaluate hydraulic seismic performance of water supply networks. In other words, it is possible to quantify the damage rate of a pipeline during an earthquake through linkage with the pipe failure probability model, and it is possible to derive more reasonable results when estimating the water outage or low-pressure area due to pipe damages. Finally, the quantifying result of the seismic performance can be used as a design criteria for preparing an optimal restoration plan and proactive seismic design of pipe networks to minimize the damage in the event of an earthquake.

• Journal of Practical Agriculture & Fisheries Research
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• v.4 no.1
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• pp.119-127
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• 2002

This study was conducted to develop the heat exchanger by utilizing the heat energy of underground water(15℃), which might be used for cooling and heating system of the agricultural facilities. We developed the heat exchanger, parallel type plat fin tube made of Aluminum(Al 6063), which was named Aloo-Heat(No. of The registration design : 0247164, by Korean Intellectual property Office). The fin of exchanger was design of the granulated surface for minimizing fouling factor and dew forms, and also placed parallel to the tube in order to minimized the resistance of flows. 1. Aloo-heat was designed to have 0.03m for inside diameter, 0.036m for outside diameter of tube, 0.0012m for thickness of fin and 0.032m for length of plat fin. 2. t was also designed to have 1.5248m²/m for outside area of heat transfer, 0.0942m²/m for inside area contacting hot liquid, and the ratio (Ra) was 16.1869. 3. Efficiency of the fin was 93 percentage when fin length was 0.032m, and the fin thickness satisfied equation $\frac{h{\rho}}{k}$< 0.2 when it was 0.0012m. 4. According to the performance test of Aloo-heat, as the temperature and rate increased, the heating value also increased, heating value was 504kJ/h·m and 6,048kJ/h·m when it was 60℃, 10 𝑙/min and 80℃, 40 𝑙/min respectively. 5. The test of heating value was confident, because correlation value(R²) was 0.9898 for the temperature and 0.9721 for flow rate of hot liquid, respectively.

• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.684-689
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• 2012

Poly(acrylic acid) (PAA) microspheres is one of the widely-used polymeric materials for the bio-field application and the electric materials. For the synthesis of PAA microspheres, the polymerization technique using surfactants is applied. After the synthesis, the purification and separation processes are required for the removal of surfactant. When general organic solvents were used, many problems, such as huge amount of waste solvent, additional separation processes, and the possibility of residual media, were occurred. Thus, High-pressure Soxhlet extraction using liquid $CO_2$ was developed to solve these problems. In this study, High-pressure Soxhlet extraction of the synthesized PAA microspheres using liquid $CO_2$ was conducted for the removal of Monasil PCA which is used for the dispersion polymerization of acrylic acid in compressed liquid Dimethyl ether (DME). The morphology of the extracted PAA particles was checked by field emission scanning electron microscopy (FE-SEM) and the residual concentration of Monasil PCA was analyzed by inductively coupled plasma - Optical Emission Spectrometer (ICP-OES). For studying the effect of the solvent effect, Soxhlet extraction was conducted using n-hexane, liquid DME, and liquid $CO_2$. In case of n-hexane, some extracted PAA microspheres were produced. However, deformation was also occurred due to the high thermal energy of n-hexane vapor. Liquid DME could not remove Monasil PCA. When using liquid $CO_2$, the extracted PAA microspheres which were free for the residual solvent were produced without deformation. For finding the optimum operating condition, high-pressure Soxhlet extraction was conducted for 8 hours with changing the temperature of reboiler and condenser. When the extractor temperature is $19.6{\pm}0.2^{\circ}C$ and the pressure is $51.5{\pm}0.5$ bar, the best removal efficiency was obtained.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.10
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• pp.1406-1413
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• 2016

This study was carried out to evaluate the toxicity of ethanolic extracts of Morus alba L. branch (ME). In the reverse mutation test, Salmonella Typhimurium TA98, TA100, TA1535, TA1357, and Escherichia coli WP2uvrA were used to estimate the mutagenic potential of ME. Sprague-Dawley rats were orally administered ME at levels of 1,250, 2,500, and 5,000 mg/kg for the single-dose toxicity test and 500, 1,000, and 2,000 mg/kg/d for the repeated-dose toxicity test for 28 consecutive days. As expected, reverse mutation was not detected at any concentration of ME, regardless of application of the metabolic activation system with or without S9 mix. In the single-dose toxicity test, ME caused neither significant visible signs of toxicity nor mortality in rats, and $LD_{50}$ was estimated to be over 5,000 mg/kg. In the repeated-dose toxicity test, ME administration at 500, 1,000, and 2,000 mg/kg for 28 days to male or female rats did not result in mortality. Similarly, no toxicologically significant treatment-related changes in body weight, food intake, or organ weights were noted. Several hematological and biochemical parameters in both genders showed significant differences, but these were within normal ranges. These results support the safe use of ME.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.4
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• pp.267-275
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• 2000

In an effort to assess the reliability of satellite altimeter system, we conducted a comparative analysis of sea level data that were collected using the TOPEX/POSEIDON (T/P) altimeter and the 10 tide gauge (TG) stations in the satellite passing track. The analysis was made using data sets collected from marginal sea regions surrounding the Korean Peninsula at T/P cycles of 2 to 230, which correspond to October 1992 to December 1998. Because of strong tidal activity in the study area, treatment of tidal errors is a very critical step in data processing. Hence in the computation of dynamic heights from the Tn data, we adapted the procedures of Park and Gamberoni (1995) to reduce errors associated with it. When these T/P data were treated, the alias periods of M$_2$, S$_2$, and K$_1$ constitutions were found at 62.1, 58.7, and 173 days. The compatibility of the T/P and TG data sets were examined at various filtering periods. The results indicate that the low-frequency signal of Tn data can be interpreted more safely with longer filtering periods (such as up to the maximum selected values of 200 days). When RMS errors for 200-day low-pass filter period was compared among the whole 10 tidal stations, the values spanned in the range of 2.8 to 6.7 cm. The results of correlation analysis at this filtering period also showed a strong agreement between the Tn and TG data sets over the whole stations investigated (e.g., P values consistently less than 0.0001). According to our analysis, we conclude that the analysis of surface sea level using satellite altimeter data can be made safely and reasonably long filtering periods such as 200 days.

• Journal of Animal Science and Technology
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• v.49 no.1
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• pp.121-128
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• 2007

The objective of this study was to determine the efficacy of different water temperatures and time of spray-washing on the removal of bacteria contamination from surface of pork carcass and to obtain better meat quality with high temperature stream between 60 to 90℃ for the time ranged from 10 to 60 sec. Results showed that total plate counts were significantly decreased with increasing steam temperature(P<0.05). Similar results were found with the spray time(P<0.05). The lightness(CIE L*) value was significantly increased in both loin and ham cuts over 80℃(P<0.05). Ultimate pH of muscle and water-holding capacity were decreased with increasing steam temperature(P<0.05). There was a significant difference in solubility of sarcoplasmic protein between 70℃ and 80℃ of the steam treatments with higher value at 70℃(P<0.05). Again, longer than 30 sec spray at 70℃ steam, the lightness value of pork was significantly increased(P<0.05), while pH and water-holding capacity of muscle were significantly decreased(P<0.05). Therefore, a desirable pork quality would be achieved with spray-steam washing at 70℃ for 20 sec on pork carcass.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.4
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• pp.619-627
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• 2008

The objective of this study was to compare the microleakage of five adhesive systems in the enamel and dentin of permanent teeth. Class V cavity preparations with occlusal margins in enamel and gingival margins in dentin were prepared on both buccal and lingual surfaces of 25 extracted human molar teeth. The tested adhesives were: Adper Scotchbond Multi-purpose Plus Adhesive (SM), Adper Single bond 2 (SB), Clearfil SE Bond (SE), Adper Prompt L-Pop (PL) and G-Bond (GB). The results were as follows: 1. At the enamel margins, PL showed the highest leakage value(0.85), and others showed values of SB(0.55), GB(0.50), SM(0.35) and SE(0.25) in decreasing order. There were statistically significant differences in PL vs. SM and PL vs. SE(p<0.05). 2. At the dentin margins, GB showed the highest leakage value(2.10), and others showed values of SE(1.45), PL(1.40), SB(1.05), SM(0.70) in decreasing order. There were statistically significant differences in GB vs. SB and GB vs. SM(p<0.05). 3. Dentin margins showed high dye penetration rate than enamel margins in all material tested groups and there were statistically significant differences for SE, PL and GB.