• Journal of Bio-Environment Control
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• v.21 no.3
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• pp.207-212
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• 2012

The objective of the present study is to identify the physico-chemical characteristics of used plug media (UPM) and its effect on growth response of tomato and cucumber seedlings. The UPM from commercial media Mix#5 (Sungro co., Ltd.) was used in this study. This media was sterilized by sterilizer at $120^{\circ}C$ in 30 minutes at 1.5 atm. Physicochemical properties of UPM was compared with new plug media (NPM). Physical properties such as air volume, particle density, solid volume, bulk density were investigated by three phase device (DIK-1130, Japan). And chemical characteristics such as $NO_3$-N, $P_2O_5$, K, Mg, Ca, $SiO_2$, CEC, OM were investigated by soil spectrophotometer (PTIZEN 1412SA, Mecasys Co., Ltd). The result indicates that air volume and water holding capacity of UPM are lower than NPM (25%, 15%, respectively). Bulk density and soil weight are more than two times higher than NPM per unit volume. Compared to NPM, there were no significant different for pH and EC. But CEC of UPM is lower than NPM 40%. In order to compare growth response and ability absorption of inorganic elements by plants, cucumber and tomato seedlings were used and chemical characteristics after growing of mediums were determined. The result indicated that seeding quality of tomato and cucumber in UPM is less than in NPM and almost inorganic ions of UPM are lower than NPM. So it is necessary to improve physicochemical properties of UPM.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.3
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• pp.231-241
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• 1992

To study the relationships between major micrometeorological elements and their influences on evapotranspiration(ET) in the canopy of two rice cultivars, Daecheongbyo and Samgangbyo, synoptic meteorological factors, micrometeorological elements and ET from the canopy and biomass production were observed at various growth stages in the paddy field of Suwon Weather Forcast Office in 1989. ET from the rice community was highly correlated with the following factors in order of pan evaporation>air temperature>leaf temperature>solar radiation>sunshine duration>difference in vapor pressure depicit(VPD)>water temperature. ET observed showed higher correlation with the evaporation from small pan than that from Class A pan. Varietal difference would be noted in the relationships between ET in Samgangbyo canopy and the evaporations observed from the pans, with which closer a correlation was found in Samgangbyo than in Daecheongbyo. The ratio of canopy ET to the evaporation from Class A pan was maintained over 1.0 through the growth stages with the maximum of 1.9 at the late August. The evaporation observed from Class A pan was amounted to 71.9% of that from small pan. ET was better correlated with solar radiation than with net radiation which reached about 66% of solar radiation. Maximum temperature showed higher correlation with ET than mean air temperature, and also wind speed of 1m above ground revealed positive correlation. The relative humidity, however, had no correlation with the exception of ET in rainy days. A regression model developed to estimate ET as a function of meteorological elements being described with $R^2$ of 0.607 as : $ET=-5.3594+0.7005Pan\;A+0.1926T_{mean}+0.0878_{sol}+0.025RH$.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.3
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• pp.46-53
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• 2009

Urbanization brings several changes to the natural environment. Its consequences can have a direct effect on climatic features, as in the Urban Heat Island Effect. One factor that directly affects the urban climate is the green area. In urban areas, vegetation is suppressed in order to accommodate manmade buildings and streets. In this paper we analyze the effect of green areas on the urban temperature in Seoul. The period selected for analysis was July 30th, 2007. The ground temperature was measured using Landsat TM satellite imagery. Land cover was calculated in terms of city area, water, bare soil, wet lands, grass lands, forest, and farmland. We extracted the surface temperature using the Linear Regression Model. Then, we did a regression analysis between air temperature at the Automatic Weather Station and surface temperature. Finally, we calculated the temperature decrease area and the population benefits from the green areas. Consequently, we determined that a green area with a radius of 500m will have a temperature reduction area of $67.33km^2$, in terms of urban area. This is 11.12% of Seoul's metropolitan area and 18.09% of the Seoul urban area. We can assume that about 1,892,000 people would be affected by this green area's temperature reduction. Also, we randomly chose 50 places to analysis a cross section of temperature reduction area. Temperature differences between the boundaries of green and urban areas are an average of $0.78^{\circ}C$. The highest temperature difference is $1.7^{\circ}C$, and the lowest temperature difference is $0.3^{\circ}C$. This study has demonstrated that we can understand how green areas truly affect air temperature.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.235-240
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• 1979

A study on the amino acid composition of raw frozen krill, and krill solubles manufactured in forms of paste and powder has been carried out. The raw frozen krill was thawed, chopped, mixed and homogenized with same amount of water. The mixture was autolyzed or hydrolyzed by tile addition of $0.2\%$ pronase-p, a commercial proteolytic enzyme, to the weight of the raw frozen krill at $45^{\circ}C$ for 4 hours. After a thermal inactivation of enzymes at $95^{\circ}C$ for 15 minutes, the autolysate and the hydrolysate were centrifuged and filtered through gauzes, respectively, and then tile lipid layer in the supernatant was removed, The autolysate and the hydrolysate were finally concentrated under reduced atmospheric pressure in a rotary vacuum evaporator at $45^{\circ}C$ for 1 hour to produce the krill solubles in form of paste. The powdered krill solubles were prepared by the addition of $5\%$ starch to the autolysate and hydrolysate and by means of concentration in the rotary vacuum evaporator at $45^{\circ}C$ for 30 minutes and a forced air drying at $58^{\circ}C$ for 3 hours with a air velocity of 3m/sec. Among the amino acids in raw frozen krill, glutamic acid, lysine, and aspartic acid showed high values in quantity and then followed leucine, alanine, arginine, glycine and proline. The qnantity of histidine was very small and that of cystine was only in trace. The krill solubles in forms of paste and powder prepared by autolysis and hydrolysis with pronase-p revealed almost the same patterns in amino acid composition as in raw frozen krill. In case of free amino acids, a large quantity of it in raw frozen krill consisted of lysine, arginine, proline, alanine and leucine. The quantities of cystine, histidine and glutamic acid were, in contrast, very small. In the soluble krill paste prepared by autolysis, lysine, leucine, threonine and alanine existed in large quantities among the free amino acids and cystine, aspartic acid and histidine existed in small quantities. The contents of almost all of the free amino acids ill soluble krill paste perpared by hydrolysis with pronase-p were increased slightly as compared with those in soluble krill paste prepared by autolysis. In this product, the contents of cystine, histidine and serine were very low and lysine, leucine, arginine and proline were the dominant group in quantities among the free amino acids. The krill solubles in forms of paste and powder were not inferior to whole egg in the view point of its essential amino acid composition.

• Korean Journal of Environmental Agriculture
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• v.36 no.2
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• pp.113-118
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• 2017

BACKGROUND: The carbon (C) isotope ratio (${\delta}^{13}C$) of dissolved organic C (DOC) is an indicator of water pollution source. In this study, the potential use of two pre-treatments for the ${\delta}^{13}C$ analysis, alkaline persulfate oxidation coupled with carbonate precipitation (precipitation) and freeze drying (drying), were compared to suggest a more feasible pre-treatment method. METHODS AND RESULTS: Two reference materials with different ${\delta}^{13}C$ values were used for the experiments; chemical grade glucose ($-12.0{\pm}0.02$‰) and pig manure compost extract ($-23.3{\pm}0.04$‰). In the precipitation method, the measured ${\delta}^{13}C$ values were consistently lower than the theoretically calculated values as dissolved $CO_2$ could not be removed due to the alkaline property of the reagents and the dissolution of air $CO_2$ into the alkaline solution. The drying method also resulted in more negative ${\delta}^{13}C$ than the calculated ${\delta}^{13}C$; however, the difference was systematic ($3.9{\pm}0.3$‰) and there was a strong correlation (${\delta}^{13}C_{calculated}=0.87{\times}{\delta}^{13}C_{measured}-0.624$, $r^2=0.98$) between the calculated and measured ${\delta}^{13}C$. Calibration of ${\delta}^{13}C$ using the relationship between the calculated and the measured ${\delta}^{13}C$ values produced reliable and accurate ${\delta}^{13}C$ values. CONCLUSION: Our results suggest that the drying method is more accurate pre-treatment method to minimize the influence of air $CO_2$ compared to the precipitation method for the determination of ${\delta}^{13}C$ of DOC.

• Progress in Medical Physics
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• v.15 no.4
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• pp.202-209
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• 2004

Flat panel based digital radiography (DR) systems have recently become useful and important in the field of diagnostic radiology. For DRs with amorphous silicon photosensors, CsI(TI) is normally used as the scintillator, which produces visible light corresponding to the absorbed radiation energy. The visible light photons are converted into electric signal in the amorphous silicon photodiodes which constitute a two dimensional array. In order to produce good quality images, detailed behaviors of DR detectors to radiation must be studied. The relationship between air exposure and the DR outputs has been investigated in many studies. But this relationship was investigated under the condition of the fixed tube voltage. In this study, we investigated the relationship between the DR outputs and X-ray in terms of the absorbed energy in the detector rather than the air exposure using SPEC-l8, an X-ray energy spectrum model. Measured exposure was compared with calculated exposure for obtaining the inherent filtration that is a important input variable of SPEC-l8. The absorbed energy in the detector was calculated using algorithm of calculating the absorbed energy in the material and pixel values of real images under various conditions was obtained. The characteristic curve was obtained using the relationship of two parameter and the results were verified using phantoms made of water and aluminum. The pixel values of the phantom image were estimated and compared with the characteristic curve under various conditions. It was found that the relationship between the DR outputs and the absorbed energy in the detector was almost linear. In a experiment using the phantoms, the estimated pixel values agreed with the characteristic curve, although the effect of scattered photons introduced some errors. However, effect of a scattered X-ray must be studied because it was not included in the calculation algorithm. The result of this study can provide useful information about a pre-processing of digital radiography.

• Food Science and Preservation
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• v.14 no.2
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• pp.148-153
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• 2007

The chemical components of flesh persimmon flowers (petal and calyx), and the qualify of hot-water extracts (teas) prepared from powders of these flower parts, were investigated In flesh petal and calyx, the contents of moisture, crude protein, crude lipid, and carbohydrate were 84.8% 0.4% 0.3% and 13.7% respectively. The values were not significantly different when the two tissues were compared. In petal and calyx respectively, the crude ash values were 0.5% and 1.1% of flesh weights, the vitamin C content were 192.3mg% and 392.7ng%, the flavonoid levels were 98.4 mg% and 355.2mg% and the carotenoid content were 0.8mg% and 3.8mg%. Hot air and freeze drying methods applied to petals, prior to powder preparation, did not affect the levels of soluble solids or soluble annins. Extract from calyx had higher L values, higher ${-\alpha}$ values, more soluble tannins, greater 1,1-diphenyl-2-picrylhy-drazylradical-scavenging activities, me lower pH values, than did exracts from petal. Fructose and glucose were higher in petal extract than in calyx extract, but sucrose was higher in calyx extracts. Extract of freeze-dried powdered petals had significantly higher free sugar levels than did exracts from petals dried with hot air. The major organic acids in extracts were citric acid, oxalic acid, and malic acid. The levels of organic acids were inversely related to free sugar levels in all flower parts and after all drying methods tested. Sensory tests of aroma, taste and overall acceptability yielded scores above medium for all teas, regardless of the flower part powdered, or the drying method used. The results show that the petal and calyx of persimmon may be used to make tea and perhaps other foods.

• The Korean Journal of Air & Space Law and Policy
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• v.34 no.1
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• pp.235-268
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• 2019

Under the Aviation Safety Act of Korea, any person who intends to operate a drone is required to follow the operational conditions listed below, unless approved by the Minister of Land, Infrastructure, Transport and Tourism; (i) Operation of drones in the daytime, (ii) Operation of drones within Visual Line of Sight, (iii) Maintenance of a certain operating distance between drones and persons or properties on the ground/ water surface, (iv) Do not operate drones over event sites where many people gather, (v) Do not transport hazardous materials such as explosives by drone, (vi) Do not drop any objects from drones. Requirements stated in "Airspace in which Flights are Prohibited" and "Operational Limitations" are not applied to flights for search and rescue operations by public organizations in case of accidents and disasters. This paper analyzes legal issues as to definition and regulations of drones in Korean Aviation Safety Act. This paper, also, offers some implications and suggestions for regulations of drones under Korean Aviation Safety Act by comparing the regulations of drones in Japanese Civil Aeronautics Act.

• Journal of the Korean Geotechnical Society
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• v.31 no.7
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• pp.5-12
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• 2015

In this study, the deposition of dredged soils from domestic rivers is simulated in the laboratory using a small soil box. In the tests, small sand with 0.002-0.85 mm, large sand with 0.85-2 mm, and gravel 4.75-5.6 mm are air or water-pluviated into the box. Such various deposition processes are simulated and their dry densities are measured. While dredging or piling such soils, their volume may change. The loss of such soils is calculated by a soil conversion factor C. The C value was determined as 0.91 for small sand, 0.96 for large sand, and 0.91 for gravel. The drainage through soil piles may occur and result in effective stress increase. This may cause the volume change of soils and in order to consider such effect it is necessary to recalculate C values. As a result, dry density increased by 5-12% when the drainage effect is considered. When the drainage effect is considered, the value of soil conversion factor C was 0.81 for small sand, 0.92 for large sand, and 0.82 for gravel. Eventually, the C value decreased up to 4-12%.

• Journal of the Korea Concrete Institute
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• v.16 no.5 s.83
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• pp.605-612
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• 2004

This study investigated the fundamental properties and shrinkage properties of high performance concrete with water/binder ratio of 0, 30 and with combination of expansive additive and shrinkage reducing agent. According to the results, the fluidity of high performance concrete showed lower the using method in combination with expansive additive and shrinkage reducing agent than the separately using method of that, so the amount of superplasticizer increased when the adding ratio of expansive additive and shrinkage reducing agent increased. However the air content of concrete increased when used in combination with expansive additive and shrinkage reducing agent, so the amount of AR agent decreased. The compressive strength showed the highest at $5\%$ of expansive additive, and decreased with an increase of the amount of shrinkage reducing agent. Furthermore, in order to reduce the shrinkage of high performance concrete, it was found that the using method in combination with expansive additive and shrinkage reducing agent was more effective than separately using method of that. Therefore, it analyzed that the combination of expansive additive of $5\%$ and shrinkage reduction agent of $1\%$ was the most suitable mixture, considering to the fluidity, strength and shrinkage under the condition of this experiment.