• Magazine of the Korean Society of Agricultural Engineers
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• v.15 no.1
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• pp.2853-2877
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• 1973

Models of cross-sections and channels were made in order to measure seepage losses. Cross-sections were made of sand, sandy clay loam and loam, their thicknesses being 30cm and 40cm, respectively. Flow depths kept in the cross-sections were 4cm, 6cm, 8cm and 10cm. Straight and curved channel models were provided so as to measure seepage losses, when constant water depths maintained at the heads of the channels were 7.3cm and 5.7cm, respectively. The results obtained in this experiment are presented as follows: 1) A cumulative seepage loss per unit length at a point in the channel varies in accordance with time and flow depth. The general equation of cumulative seepage loss may be as follows(Ref. to Table V.25): $$q_{cum}=\int_{o}^aq(a)dt+\int_a^bq(b)dt+\int_b^tq(c)dt$$ 2) In case that the variation of water depth through the channel is slight, the total seepage loss may be computed by applying the following general equation: $$\={q}_{cum}{\cdot}x=\int_o^tq_{cum}\frac{{\partial}x}{{\partial}t}dt$$ 3) Because seepage loss varies considerably according to water depth in case that the variation of flow depth through the channel is great, seepage loss should be computed by taking account of the change of flow depth. 4) The relation between time and traveling distance of water flow may be presented as the following general equation(Ref. to Table V.29): $$x=pt^r$$ 5) The ratios of the seepage losses of the straight channel to the curved channel are 1:1.03 for a flow depth of 7.3cm and 1:1.068 for that of 5.7cm. 6) The ratios of the seepage losses occurring through the bottom to those through the inclined plane in the channel cross-section are 1:2.24 for a water depth of 8cm and 1:2.47 for a depth of 10cm in case that soil-layer is 30cm in thickness. Similarly, those ratios are 1:2.62 and 1:2.93 in case of a soil-layer thickness of 40cm(Ref. to Table V.5).

• Journal of Korean Society of Water and Wastewater
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• v.35 no.6
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• pp.455-463
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• 2021

The adsorption process using GAC is one of the most secured methods to remove of phosphate from solution. This study was conducted by impregnating Cu(II) to GAC(GAC-Cu) to enhance phosphate adsorption for GAC. In the preparation of GAC-Cu, increasing the concentration of Cu(II) increased the phosphate uptake, confirming the effect of Cu(II) on phosphate uptake. A pH experiment was conducted at pH 4-8 to investigate the effect of the solution pH. Decrease of phosphate removal efficiency was found with increase of pH for both adsorbents, but the reduction rate of GAC-Cu slowed, indicating electrostatic interaction and coordinating bonding were simultaneously involved in phosphate removal. The adsorption was analyzed by Langmuir and Freundlich isotherm to determine the maximum phosphate uptake(q_m) and adsorption mechanism. According to correlation of determination(R²), Freundlich isotherm model showed a better fit than Langmuir isotherm model. Based on the negative values of q_m, Langmuir adsorption constant(b), and the value of 1/n, phosphate adsorption was shown to be unfavorable and favorable for GAC and GAC-Cu, respectively. The attempt of the linearization of each isotherm obtained very poor R². Batch kinetic tests verified that ~30% and ~90 phosphate adsorptions were completed within 1h and 24 h, respectively. Pseudo second order(PSO) model showed more suitable than pseudo first order(PFO) because of higher R². Regardless of type of kinetic model, GAC-Cu obtained higher constant of reaction(K) than GAC.

• The Korean Journal of Nuclear Medicine
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• v.13 no.1_2
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• pp.7-14
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• 1979

Radionuclide cardiac angiography has distinct advantages in safety, patient comfort, cost and ease of performance. This method offers diagnostic accuracy equivalent to that of cardiac catheterization. By this method the qualitative and quantitative diagnosis of the cardiac shunts are available. Also for it is repeatable with ease and more physiologic, it has application in following pre- and post-operative shunt patients. We performed the radionuclide cardiac angiographies in 147 cases of heart diseases and 26 cases of normal group. 1. The detection of left-to-right shunt was possible in 22 of 24 patients, and 2 patients were not diagnosed due to small shunt amount. (Qp/Qs<1.3) In 21 patients of right-to-left shunt, all were diagnosed by radionuclide cardiac angiography. 2. With the pulmonary time-activity curve, $C_2/C_1$ ratio was calculated. In normal control group, a range of $C_2/C_1$ ratios of $21{\sim}38%$ was established with a mean value of $28.6{\pm}4.6%$. In patients with left-to-right shunts determined by catheterization data, the range of $C_2/C_1$ ratio was $33{\sim}90%$, with a mean value of $67.8{\pm}12.2%$. 3. In 8 cases of left-to-right shunt, $Q_p/Q_s$ ratios determined by radionuclide cardiac angiography were compaired with those of cardiac catheterization. The correlation coefficient was 0.907. (P<0.001) 4. Postoperative radionuclide cardiac angiographies were done in 21 cases. 3 of 13 patients with left-to-right shunts were found to have residual shunts. 8 patients with right-to-left shunts were confirmed to have no residual shunt.

• Fashion & Textile Research Journal
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• v.6 no.2
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• pp.221-228
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• 2004

The purpose of this study was to compare somatotypes from various classification methods, to analyze the interrelation among each somatotype or each high frequency type, and to suggest the basis to interpret body size and shape more accurately. As a sample, the subjects were 97 Korean females between 18 and 24 years old. They were measured both anthropometric and photographic measuring in November, 1999. Their somatotypes were classified by three kinds of classification methods. The first method was based on the lateral view of body, the second involved Factor and Cluster analysis with the photographic measurements of anterior and lateral body, and the third involved Factor and Cluster analysis with the anthropometric measurements of whole body. The upper body was classified into three types, and the lower body was classified into 6 types from the lateral view of body. The bend-forward/q-2 was found to be the 'High-frequency type from the lateral view of body', and the Straight/n-1 was found to be the 'Straight type from the lateral view of body'. From the classification by the analysis of photographic measurements, the anterior body was classified into three types, the lateral was classified into 4 types. The X/${\varepsilon}$ type was found to be the 'High-frequency type from the analysis of photographic measurements of anterior and lateral body'. From the classification by the analysis of anthropometric measurements, the whole body was classified into three types. The i type was found to be the 'High-frequency type from the analysis of anthropometric measurements of whole body'. The significant interrelation was certified among some somatotypes or some High-frequency types. We found that both the view of body and the statistical analysis would make the clear definition of each somatotype possible. In order to certify the representativeness of High-frequency type, further analysis would be required of subjects who were in the High-frequency type and their body parts were in the High-frequency range.

• Korean Journal of Environment and Ecology
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• v.24 no.6
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• pp.708-722
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• 2010

This study was carried out to classify vegetation structure of the Hyangjeokbong in the Deogyusan National Park using the gradient analysis and phytosociological method. The vegetation was classified into Quercus mongolica community(Rhododendron schlippenbachii subcommunity, typical subcommunity), Q. serrata community, Q. variabillis community, Pinus densiflora community, Cornus controversa community, Fraxinus mandshurica community and Taxus cuspidata community. Ecological characteristics such as species composition, layer structure, vegetation ratio, and the distribution of individual trees by DBH(diameter at breast height) were significantly different among communities. The order of important value of the forest community with DBH 2cm above plants was Q. mongolica(81.2), F. mandshurica, Q. serrata, P. densiflora, Acer pseudosieboldianum, Q. variabillis, Rhododendron schlippenbachii, C. controversa, T. cuspidata. Distribution of DBH of Q. mongolica and Q. serrata had suggesting a continuous domination of these species over the other species for the time being. In contrast, F. mandshurica appeared limited to the valley of the sheet and a higher frequency of young individuals, suggesting a continuous domination of these species the development of a climax forest terrain. P. densiflora and T. cuspidata had suggesting a continuous domination of these species over the other species for the time being in maintain. Q. variabilis and C. controversa had a formality distribution, suggesting a continuous domination of these species over the other species for the time being. This study examined the correlation between each community and the environment according to DCCA ordination. The Q. mongolica community and T. cuspidata community predominated in the highest elevation habitats which had few moisture, Ca and in the low pH. The Q. serrata community mainly occurred in the low elevation habitats which had many moisture. P. densiflora community predominated in the middle elevation and south-facing slope habitats which had few moisture, Ca and in the low pH. F. mandshurica community predominated in the low elevation habitats which had many moisture, Ca and pH.

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.6
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• pp.473-479
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• 2020

Endothelial cell injury is a major contributor to cardiovascular diseases. The 2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-Glucoside (TSG) contributes to alleviate human umbilical vein endothelial cells (HUVECs) injury through mechanisms still know a little. This study aims to clarify the TSG effects on gene expression (mRNA and microRNA) related to oxidative stress and endoplasmic reticulum stress induced by H₂O₂ in HUVECs. We found that TSG significantly reduced the death rate of cells and increased intracellular superoxide dismutase activity. At qRT-PCR, experimental data showed that TSG significantly counteracted the expressions of miR-9-5p, miR-16, miR-21, miR-29b, miR-145-5p, and miR-204-5p. Besides, TSG prevented the expression of ATF6 and CHOP increasing. In contrast, TSG promoted the expression of E2F1. In conclusion, our results point to the obvious protective effect of TSG on HUVECs injury induced by H₂O₂, and the mechanism may through miR16/ATF6/ E2F1 signaling pathway.

• Journal of Korea Foresty Energy
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• v.7 no.1
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• pp.11-21
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• 1987

To estimate the biomass, net production and nutrient distribution of Pinus Koraiensis and Quercus mongolica stand, experimental plots located in Kwangju of Kyonggi-do were selected. Ten sample trees selected account of DBH distribution were felled and the diagram of oven-dry weight distrubution of leaves, branches and stems for each 1m segment was constructed. The logarithmic regression equations between dry weight of each component and the variable of $(DBH)^2$ H obtained. The standing crops were estimated to be as much as 152.07 and 156.02 tons of dry matter per hectare in P. koraiensis and Q. mongolica stand respectively. The net production was estimated as 24.66 and 20.35t/ha$\cdot$yr and the net assimilation rate was 1.90 and 3.42kg/kg$\cdot$yr in same order. Particulary large proportions of nitrogen. calcium and magnesium were found in soil of P. koraiensis stand, phosphours and potassium in overstory of it. At Q. mongolica stand, large proportions of nitrogen. phosphorus. potassium and magnesium were found in soil and calcium in overstory. The amounts of litter fall was 4.013t/ha$\cdot$8 months in P. koraiensis stand and 3.490t/ha$\cdot$8 months in Q. mongolica stand.

• Journal of Korea Water Resources Association
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• v.51 no.2
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• pp.141-150
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• 2018

The purpose of this study is to evaluate the future hydrologic behavior affected by the potential climate and land use changes in upstream of Anseong-cheon watershed ($366.5km^2$) using SWAT. The HadGEM3-RA RCP 4.5 and 8.5 scenarios were used for 2030s (2020-2039) and 2050s (2040-2059) periods as the future climate change scenario. It was shown that maximum changes of precipitation ranged from -5.7% in 2030s to +18.5% in 2050s for RCP 4.5 scenarios and the temperature increased up to $1.8^{\circ}C$ and $2.6^{\circ}C$ in 2030s RCP 4.5 and 2050s 8.5 scenarios respectively based on baseline (1976-2005) period. The future land uses were predicted using the CLUE-s model by establishing logistic regression equation. The 2050 urban area were predicted to increase of 58.6% (29.0 to $46.0km^2$). The SWAT was calibrated and verified using 14 years (2002-2015) of daily streamflow with 0.86 and 0.76 Nash-Sutcliffe model efficiency (NSE) for stream flow (Q) and low flow 1/Q respectively focusing on 2 drought years (2014-2015) calibration. For future climate change only, the stream discharge showed maximum decrease of 24.2% in 2030s RCP 4.5 and turned to maximum increase of 10.9% in 2050s RCP 4.5 scenario compared with the baseline period stream discharge of 601.0 mm by the precipitation variation and gradual temperature increase. While considering both future climate and land use change, the stream discharge showed maximum decrease of 14.9% in 2030s RCP 4.5 and maximum increase of 19.5% in 2050s RCP 4.5 scenario by the urban growth and the related land use changes. The results supported that the future land use factor might be considered especially for having high potential urban growth within a watershed in the future climate change assessment.

• Tribology and Lubricants
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• v.10 no.3
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• pp.18-28
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• 1994

Sliding friction between a spherical pin of 8mm in diameter and flat (disk) substrates coated with vacuum-deposited thin film was measured under ultra high vacuum pressure for various materials, various rates of film supply (8~210 nm/min), various sliding velocities (1.5~67.0 mm/s). It was found that the most effective lubrication was obtained when the adhesion between $Si_3N_4$ pin and SUS440C disk was high and that between $Si_3N_4$ pin and $Si_3N_4$ disk was low. When In film was used as a lubricant between $Si_3N_4$ pin and stainless steel disk, the friction coefficient had a value as low as 0.04. In this case, the normal load W and the sliding speed V were expressed as 10N and 24 mm/s for $10^{-6}Pa$. The dependence of $\mu$ on the thickness h of the Ag film, which was used as a lubricant between $Si_3N_4$ pin and SUS440C (Q) disk was expressed as $\mu$=0.12 for W=10N and V=24mm/s when the film was thicker than 100nm. A brief discussion on these relations is presented from the viewpoint of the real contact area.

• Journal of Korean Society of Forest Science
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• v.99 no.6
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• pp.878-884
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• 2010

Ozone sensitivity of physiological indicators and the difference of ozone tolerance on 4 families of Quercus aliena seedlings were investigated on the basis of the standardized physiological indicators. Photosynthetic parameters, photosynthetic pigment and malondialdehyde (MDA) content, and antioxidative enzyme activities were measured or analyzed from the leaves of Q. aliena seedlings at the end of ozone fumigation, and ozone tolerance indices among 4 families were calculated with the standardized physiological parameters. After ozone treatment, the reduction of carboxylation efficiency was observed in the leaves of four families, and their reduction were ranged from -24.1% to -56.9% of control seedlings. Photosynthetic pigment content differed significantly among 4 families and treatments. The reduction of total chlorophyll content showed the highest in family SU4 (-40.6%) and the lowest family US2 (-18.8%). Ascorbate-peroxidase (APX) activity showed significant difference among families and treatments, and increased as compared with control in three families, except for family US2. On the basis of the physiological indices, ozone tolerance of four families was ranked in the order of US1 > SU4 > US2 > SU1. In conclusion, photosynthetic parameters, pigment content and APX activity were recommended as appropriate indicators to assess the tolerance against ozone stress of Q. aliena.