• Journal of the Korea Concrete Institute
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• v.18 no.4 s.94
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• pp.517-526
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• 2006

In this study, in order to utilize waste concrete powder(WCP) which is occurred in manufacturing high quality recycled aggregate as an admixture for self-compacting concrete(SCC), the properties of cement paste, mortar, and concrete that were mixed two types of WCP, 928 and 1,360 $cm^2/g$ of surface area, were analyzed. As a result of experiment, we have found that WCP was a porous material with angle. When WCP was utilized as an admixture for SCC, its flowability and viscosity increased in proportion to the increase of a replacement ratio, and that a replacement ratio of WCP was proper within 15%. The compressive strength at 28 days mixed respectively with WCP2, 15 and 30%, showed about 36 and 28 MPa, and it showed a similar trend with a function suggested in CEB-FIP for the relationship of compressive strength and elastic modulus. According to the results, it is judged that WCP2 can be utilized as an mineral admixture of normal strength SCC.

• Ecology and Resilient Infrastructure
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• v.3 no.4
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• pp.302-306
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• 2016

There are various methods to evaluate tree vigor. Cambial electrical resistance represents tree vigor using the method of electrophysiological diagnosis. This study investigated the vigor of several tree species using Shigometer, and compared the differences among the species. The factors, such as foliation, trunk orientation and bark temperature, which affect electrical resistance were also investigated. The needle penetration into cambium was controlled to keep the depth consistent in order to minimize measurement error. Each of three trees were selected from Zelkova serrata, Ginkgo biloba, Metasequoia glyptostroboides, Pinus koraiensis, and Liriodendron tulipifera. The electrical resistances were measured at 60 and 120 cm height of the stem in 4 directions from March until May 2011. The soil conditions in surrounding areas and tree stress responses were also measured. The results were analyzed for the relationship between electrical resistance and the affecting factors. The electrical resistance showed a relatively higher level before foliation until mid-March. The values started to decline from April and recorded a minimal level on May 11. The changes of soil moisture, soil electric conductivity, and tree stress responses during the measurement period showed a similar trend to that of electrical resistance. The Pinus koraiensis, an evergreen conifer, showed few changes on the electrical resistance values during the measurement period. Zelkova serrata, Ginkgo biloba, and Metasequoia glyptostroboides showed the highest bark temperatures and lowest electrical resistances at their south-facing stem. Shigometer can provide measures simple to assess tree vigor in the fields, and to the management of trees.

• Journal of Korea Soil Environment Society
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• v.3 no.2
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• pp.61-70
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• 1998

This research has been made for influence of forest environmental changes, such as tree-clearcutting affecting to soil chemical and physical properties, on water storage capacity at forest fire land in Keumsan, Chungnam. The analyzed factors were bulk density, porosity, field moisture saturated hydraulic conductivity air permeability and organic matter content, Field moisture saturated hydraulic conductivity and air permeability at uncutting sites were higher than those at clearcutting sites, especially the most differences were appeared at lower slope. After 2 years passed since forest fire, the most changeable parts of soil characteristics were 5-l5cm depth below soil surface. Total Porosity, coarse pore and fine pore at uncutting sites were higher than those at clearcutting sites. Also, as soil depth increased, total porosity and coarse pore were decreased. Bulk density at uncutting sites was lower than that at clearcutting sites, and was decreased as soil depth increased. The order of the change trend in field moisture saturated hydraulic conductivity, air permeability and porosity was slope lower>middle>upper. Organic matter content at uncutting sites were higher than those at clearcutting sites, and decreased as soil depth increased. As soil depth increased, bulk density had the positive correlation, in other hand, porosity, coarse pore, field moisture saturated hydraulic conductivity, air permeability and organic matter content had the negative correlation. It was concluded that forest environmental changes by forest fire degrade soil physical and chemical properties.

• Journal of the Korean earth science society
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• v.24 no.4
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• pp.290-302
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• 2003

This study was carried out to evaluate geochemical properties for stream sediments, surrounding soils, sludge collected in the drainage pipe of leachate and waters (stream water, groundwater, leachate) around the Pungam Landfill in Gwangju city. The stream sediments don't show any systematic trend of contents from upstream to downstream. The most enriched major element in the stream sediments is Fe (up to 7.08wt.% in GJ-23). Though stream sediment GJ-23 and GJ-34 were enriched by some heavy metals (eg. As, Cu, Zn), they do not constitute serious problems for environment consideration. The concentration of Fe (35.lwt.%) and As (38ppm) are significantly high in the GJ-8, which is soil specimen adjacent to leachate reservoir. The sludge (GJ-7) shows very high concentrations of As, Mn, Cr, Pb. In particular, the Cr content is 45.6 ppm, which exceeds the permitted level. The leachate is characterized by high TDS (2210-2470mg/L) and high electric conductivity (468, 530ms/cm), and enriched in both cation (Na, K) and anion (HCO$_3$). The leachate(PK-3) had a relatively high concentration of Cl, and is plotted in Na-Cl type on the Piper's diagram. The NO$_3$-N of the groundwater and stream water exceeded the permitted levels for drinking water.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.2
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• pp.219-224
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• 1994

The purpose of this study was to investigate the percentage of body fat by measurement of skin-fold thickness and to figure out the relationship between the daily energy intake and expenditure among male and female college students. Measurements of height, weight , skinfold thickness, percent body fat, lean body mass were made, 새심 daily energy expenditure and dietary intake survey were performed on 164 (male 86, female 78) college students. The survey was conducted between October 10, 1993-November 20, 1993. The results are as follows : 1) The average height and wegiht of the surveyed men and women were respectively 172.$\pm$0.6cm, 62.2$\pm$0.8kg and 160.8$\pm$ 0.5cm, 51.5$\pm$0.6kg, BMI of those surveyed were 20.9$\pm$0.2 and 19.9$\pm$0.2 and body density of those surveyed were 1.06$\pm$0.0 and 1.05$\pm$0.0 , and the percentage of body fat of those surveyed were 17.3$\pm$0.5% and 23.2$\pm$0.4% , and IBM of those surveyed were 51.2$\pm$0.6kg and 39.5$\pm$0.4kg. 2) Mean skin-fold thickness at 4 sites of the surveyed men and women were respectively 11.6$\pm$0.5mm and 18.3$\pm$0.6mm. 3) Average calorie intake of male and female were 2121$\pm$54kcal , 1906$\pm$28kcal respectively 70.5:14.2:15.3 and 68.0:14.0:18.0. 5) Activity time record of subjects reveal that there was a trend for males to spend more time in moderate and high activity and less time in light activity compared to females. Total daily energy expenditure of male and female group were respectively 2784$\pm$51kcal and 2073$\pm$32kcal. 6) The skinfold thickness showed negative correlation with body density but it showed positive correlation with the percentage of body fat. The lean body mass showed positive correlation with physical activity and energy intake showed positive correlation with physical activity also.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.8
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• pp.1184-1188
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• 2011

This study analyzed changes in the texture and salt content of Chinese cabbage after salting using different methods to determine the effects of low salt brining. To verify the possibility of brining under low salt concentration, Chinese cabbage was salted with 1%, 2%, 6%, and 10% salt solutions by pressing, pressure reduction, or steaming. After salting, the firmness (g, determined using the puncture test) of the Chinese cabbage changed according to the brining methods used, however, an increasing trend in rigidity was observed as the salinity increased. Because the power applied during pressing or pressure reduction treatments is higher, the firmness of and penetration time on the surface of the brined Chinese cabbages after these treatments increased more in the 6% salt solution cabbage. Additionally, the Chinese cabbages treated with steam showed significantly higher firmness and penetration time than those treated by pressing and pressure reduction. As a result of pressing the 6% salt concentrated cabbage with 1.35 $kg{\cdot}f/cm^2$, a pressure reduction from 250 mmHg, and steaming at 100$^{\circ}C$ for 1 min, the cabbage had roughly 2% of the salt concentration, ultimately. These physical treatments of pressing, pressure reduction, and steaming could be used as new methods for preparing salted Chinese cabbage with low salt concentrations for general use.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.12
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• pp.781-785
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• 2016

With trend of the miniaturization and the high-functionalizing of mobile communication system, low-loss microwave dielectric materials are widely used for high frequency communication components. These dielectric materials should be co-sintered with highly electric-conducting metal such as silver or copper for high-frequency and thick film process application. Sintering temperature of $Ca(Li_{1/3}Nd_{2/3})_{0.2}Ti_{0.8}]O_{3-{\delta}}$, which has excellent dielectric properties such as ${\varepsilon}_r$ above 40, quality factor ($Q{\cdot}f_0$) above 16,000 GHz, and TCF (temperature coefficient of resonant frequency) of $-20{\sim}-10ppm/^{\circ}C$, is reported as high as $1,175^{\circ}C$, so it could not be co-sintered with silver or copper. Therefore in this study, low-temperature melting glasses of Zn-B-O and Zn-B-Si-O systems were added to $Ca[(Li_{1/3}Nb_{2/3})_{0.8}Ti_{0.2}]O_{3-{\delta}}$ to lower its sintering temperature under $900^{\circ}C$ without losing excellency of dielectric properties. With 15 weight % of Zn-B-Si-O glass and sintered at $875^{\circ}C$, specimen showed density of $4.11g/cm^3$, ${\varepsilon}_r$ of 40.1, $Q{\cdot}f_0$ of 4,869 GHz, and TCF of $-5.9ppm/^{\circ}C$. With 15 weight % of Zn-B-O glass and sintered at $875^{\circ}C$, specimen showed density of $4.14g/cm^3$, ${\varepsilon}_r$ of 40.4, $Q{\cdot}f_0$ of 7,059 GHz, and TCF of $-0.92ppm/^{\circ}C$.

• Korean Journal of Plant Resources
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• v.18 no.2
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• pp.337-342
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• 2005

This study was conducted to investigate the bark production from a top branch(Woojuk) of lacquer tree(Rhus verniciflua) that collected Rhus lacquer in summer, analyzing a relationship between several factors - diameter, tree weight, weight of Woojuk and bark. The weight of Woojuk averaged was made up $48\%$ of the tree on average. As the weight of the tree increased, however, the Woojuk showed the rising trend. It was turned out that the tree size for making 1kg of dry bark must be at least DBB 8cm. The result on Woojuk's bark was that $43.3\%$ of total trees produced a green bark of 1.1kg to 1.5kg, and most of them put out 1.5kg and less. Also the rate of trees to make 0.6kg to 1.0kg of dry bark was highest in $50.8\%$, but its production in most trees was 1.0kg and below. As the moisture content of a green bark averaged $39\%$, it is estimated that the production of 1kg in dry bark requires at least 6kg of top branch in lacquer tree.

• The Korean Journal of Physiology
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• v.2 no.2
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• pp.11-20
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• 1968

Maximal oxygen uptake was measured in thirty-three secondary school girls by means of the treadmill test. Eighteen middle school girls aged 14.0 (range: $13.0{\sim}15.9$) years and fifteen high school girls aged 16.9 (range: $16.0{\sim}18.0$) years served as subjects. Maximal treadmill run lasted for 2 minutes and 20 seconds and the expired air was collected in a Douglas bag through a J-valve during the last one minute period. In general, absolute values of various measurements in the high school girls were greater than those of the middle school girls. When values were expressed on the body weight or lean body weight basis, however, work capacity of middle school girls was superior to that of the high school girls. The detailed results are as follows: 1. In middle school girls maximal oxygen uptake was 1.78 l/min., 47.4 ml/kg body weight, 12.3 ml/cm body height, and 61.7ml/kg lean body mass. In high school girls maximal oxygen uptake was 1.93 l/min., 39.7ml/kg body weight, 12.3 ml/cm body height, and 51.2 ml/kg LBM. Although the absolute value of maximal oxygen uptake was greater in high school girls than in middle school girls, values expressed on the body weight basis showed the reverse trend, namely, values of the middle school girls was greater than those of the high school girls. 2. The ratio of maximal to resting oxygen uptake was 8.8 in the middle school girls and was 10.2 in the high school girls. 3. Maximal pulmonary ventilation in the middle school girls was 55.3 l/min. and 66.1 l/min. in the high school girls. The ratio of maximal to resting pulmonary ventilation was 10.2 in the middle school girls and 10.1 in the high school girls. 4. The correlation between body weight and maximal oxygen uptake was relatively high, namely, r=0.79 both in middle and high school girls. The correlation coefficient between body weight and maximal pulmonary ventilation was a little less that of between maximal oxygen uptake and showed a value of r=0.60 both in middle and high school girls. The lean body mass was a poor reference of maximal oxygen uptake or maximal pulmonary ventilation as compared to body weight. The correlation between maximal oxygen uptake and maximal pulmonary ventilation was high and the coefficient of correlation in middle school girls was 0.927 and in high school girls it was 0.856. 5. Maximal ventilation equivalent was 30.9 liters in middle school girls and 33.9 liters in high school girls. This indicated that no hyperventilation was induced during the maximal of oxygen uptake exercise period as related to the maximal oxygen uptake. 6. Heart rate reached to the peak value within 1.5 minutes after beginning of maximal oxygen uptake run and remained at the same peak plateau level throughout the entire running period. Heart rate decreased steeply on cessation of running and subsided slowly thereafter. The maximal heart rate was 184 beat/min. in middle school girls and 189 beat/min. in high school girls. 7. Maximal oxygen pulse was 9.4 in middle school girls and 9.9 ml/beat in high school girls.

• The Korean Journal of Physiology
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• v.2 no.2
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• pp.1-10
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• 1968

Maximal oxygen consumption measurements were performed on 15 middle school boys (age: mean 14.0, range: $13{\sim}16$ years) and 14 high school boys (age: mean 17.4, range: $16{\sim}19$ years). General body build was greater in the high school boys and absolute values of body height, body weight, skinfold thicknesses, maximal oxygen uptake, and maximal pulmonary ventilation followed the same trend. Considered on the basis of body build, however, the values of high school boys were not always greater than those of middle school boys. The following results were obtained. 1. Maximal oxygen consumption in middle school boys was 2.11 l/min., 53.7ml/kg b. weight, 13.9 ml/cm body height, and 63.7 ml/kg LBM. In high school boys the values were: 2.86 l/min., 52.7 ml/kg b.wt., 17.5 ml/cm b. height, and 57.9 ml/kg LBM. Thus, middle school boys were superior to high school boys on body weight and lean body mass basis. They were also superior to the European boys of the same age. 2. The ratio of maximal oxygen uptake to resting value was 9.7 in middle school boys, and 10.8 in high school boys. 3. Maximal pulmonary ventilation in middle school boys was 58.0 l/min., and 84.0 l/min. in high school boys. The ratio of maximal ventilation to resting value was the same as oxygen uptake, namely, 9.7 in middle school boys and 10.7 in high school boys. 4. Ventilation equivalent in middle school boys was 27.5 and 29.3 in high school boys. These values represent values of untrained male subjects. 5. Maximal heart rate in high school boys reached to 193 beat/min. and is 2.9 times that of resting heart rate. 6. Maximal oxygen pulse in high school boys was 16.6 ml/beat and was same as that of untrained subject. 7. Correlation between body weight and maximal oxygen consumption in middle school boys was r=0.570, and r=0.162 in high school boys. Correlation between lean body mass in middle school boys was r=0.499, and r=0.158 in high school boys. Interrelation between body weight and maximal pulmonary ventilation was poor. 8. The differences between trained and untrained subjects were discussed.