• Journal of the Korean Institute of Gas
• /
• v.25 no.5
• /
• pp.37-51
• /
• 2021

The pressure drop phenomenon that occurs when the same flow rate is supplied to the gas regulator was analyzed. The regulator moves the position of the piston through the interaction of the force acting on the upper and lower parts of the piston and the spring tension to release the pressure of a specific range in a specific environment as constant pressure, thereby maintaining the pressure. The flow characteristics and pressure control process of the regulator were investigated through a numerical analysis technique as the volume of the fluid inside the regulator changed. As the gap between the piston and the piston seat decreased, the pressure drop increased and the flow velocity increased. It was verified through numerical analysis that the piston was positioned at 0.12mm under the same conditions as the pressure-flow test (inlet pressure 3MPa, outlet pressure 0.8MPa, flow rate 70kg/h).

• Journal of Forest and Environmental Science
• /
• v.38 no.2
• /
• pp.102-109
• /
• 2022

This study was conducted to test the significant difference of fertility variation among families and to select superior families for acorn production in the breeding seedling seed orchards (BSSOs) of Quercus acuta and Quercus glauca. The seed orchards were located in Jeju island and established by seedlings raised from selected parents for genetic testing in 2006. In the spring of 2021, the numbers of female and male flower were counted from 5 to 10 individuals per family in the BSSOs. To test statistical significance of which parameter is not satisfied through the normality test, we used a nonparametric analysis. Correlation analysis was performed to quantify the association between female and male flower production. As the results, the significant difference of flower production among families was found in both seed orchards. The averages of female flower production were 65.3 and 181.9 in Q. acuta and Q. glauca. The positive Spearman's rank correlation was existed between male and female flower production. Broad-sense heritability on female and male flower production were 0.191 and 0.147 in Q. acuta, and 0.285 and 0.068 in Q. glauca, respectively. Sexual asymmetry (e.g., maleness index) between female and male, and contribution variation among families (e.g., parental balance) were analyzed to find reasonable alternatives in the management of seed orchards. Effective population size of seed crops was predicted as a concept of status number. Loss of gene diversity (accumulation of group coancestry) would not be alarming in the BSSOs. Our results would be helpful to select breeding materials for establishing new seed orchards and to supply genetically improved seeds of evergreen oaks, which is one of the backbones of the strategy of carbon sink in the 2050 Carbon Neutrality of Korea Forest Service.

• The Research Journal of the Costume Culture
• /
• v.31 no.4
• /
• pp.504-518
• /
• 2023

The objective of this study was to explore the symbolism associated with phoenix patterns in China and the temporal aesthetic characteristics of these patterns found in Dunhuang Mogao Grottoes. The study involved collecting examples of clothing designs featuring phoenix patterns from China Fashion Week and the Vogue website, spanning from spring and summer of 2016 to fall and winter of 2022. After collecting and organizing these examples, representative cases were selected for analysis. The objective was to identify effective techniques for incorporating phoenix patterns within the context of Dunhuang Mogao Grottoes and provided insights for future clothing design and textile pattern design research. Phoenix patterns boasted a lengthy history and were laden with symbolic meaning. Early renditions of phoenix patterns found at Mogao Grottoes in Dunhuang were relatively simplistic in design, mainly employing elements like rhythm, coordination, balance and symmetry to convey a sense of nature and gravity. Over time, these patterns evolved under the influence of the prevailing cultural backdrop, employing repeated emphasis to portray notions of abundance and tenacity. Furthermore, regarding the use of phoenix patterns in clothing, there were four prevalent expression techniques: embroidery, beading, printing, and knitting. Traditional techniques like embroidery and beadwork often prioritized aesthetic features like coordination, emphasis, and symmetry, thereby showcasing the opulent characteristics of phoenix patterns. On the other hand, printing and knitting techniques used a single phoenix pattern or a modified version to simplify designs by emphasizing or repeating aesthetic characteristics while adhering to a modern artistic approach.

• Clinics in Shoulder and Elbow
• /
• v.25 no.4
• /
• pp.274-281
• /
• 2022

Background: In the present study, the age- and sex-adjusted Constant score (CS) in a normal Indian population was calculated and any differences with other population cohorts assessed. Methods: The study participants were patients who visited the outpatient department for problems other than shoulder and healthy volunteers from the local population. Patients without shoulder pain/discomfort during activity were included in the study. Subjects with any problem that might affect shoulder function (e.g., cervical, thoracic spine, rib cage deformity, inflammatory arthritis) were excluded. Constant scoring of all participants was performed by trained senior residents under the supervision of the senior faculty. Shoulder range of movement and strength were measured following recommendations given by the research and Development Committee of the European Society for Shoulder and Elbow Surgery (2008). A fixed spring balance was used for strength measurement; one end was fixed on the floor and the other end tied with a strap to the wrist of the participant, arm in 90° abduction in scapular plane with palm facing down. Results: Among the 248 subjects (496 shoulders), the average age was 37 years (range, 18-78 years), 65.7% were males (326 shoulders) and 34.3% females (170 shoulders). The mean CS was 84.6±2.9 (males, 86.1±3.0; females, 81.8±2.9). CS decreased significantly after 50 years of age in males and 40 years of age in females (p<0.05). The mean CS was lower than in previous studies for both males and females. Heavy occupation workers had higher mean CS (p<0.05). A linear standardized equation was estimated for calculating the adjusted CS for any age. Conclusions: Mean CS and its change with age differed from previous studies among various population cohorts.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.44 no.4
• /
• pp.483-493
• /
• 2024

This study analyzed changes in groundwater recharge due to urbanization and future climate change using the SWAT hydrological model in the Anseong river basin (1,647 km²) adjacent to the west sea of Korea. The urbanization scenario was constructed based on increasing urban density and expansion, resulting in a decrease in groundwater recharge and recharge rate by 19.9 mm and 1.77 %, respectively. Future climate change scenarios were simulated using two models representing extreme rainfall and drought, with the drought model indicating that maintaining an average recharge rate of 21.6 % would be challenging. Results from the combined scenario of urbanization and extreme drought suggest that groundwater recharge during the spring season in urban areas would be most significantly affected.

• Journal of Environmental Impact Assessment
• /
• v.26 no.2
• /
• pp.127-139
• /
• 2017

Measurements of net ecosystem exchange (NEE) of $CO_2$ based on the eddy covariance technique provide reasonable carbon balance estimates in response to local environmental conditions. In South Korea, the forest ecosystems cover approximately 64% of the total area, thereby strongly affecting regional carbon balances. Cultivated croplands that cover about 17% of the total area should also be considered when calculating the carbon balance of the country. In this study, our objectives were (a) to quantify the range and seasonal variation of NEE at forest ecosystems, including deciduous, coniferous, and mixed forests, and agricultural ecosystems, including rice paddies and a potato field, in South Korea and (b) to compare NEE at ten Fluxnet sites that have the same or similar ecosystems as found in South Korea. The results showed that the forest and agricultural ecosystems were carbon sinks. In Korea, NEE at the forest ecosystems varied between -31 and $-362gC/m^2/yr$, and NEE at the croplands ranged from -210 to $-248gC/m^2/growing$ season. At the deciduous forest, NEE reached low values in late spring, early summer, and early autumn, while at the coniferous forest, it reached low values in spring, early summer, and mid autumn. The young mixed forest was a much stronger carbon sink than the old-growth deciduous and coniferous forests. During each crop growing season, beet had the lowest NEE value within six crops, followed by wither wheat, maize, rice, potato, and soybean. These results will be useful for designing and applying management strategies for the reduction of $CO_2$ emissions.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.10 no.1
• /
• pp.27-35
• /
• 1990

As a part of studies on potassium(K) behavior in grassland with respect to magnesium(Mg) balance of ruminants, seasonal variation of K and Mg contents of forages including native gasses grown in grazing pasture and meadow were investigated. During an experimental period from April to October of 1984, two times of grazings were carried out in the orchardgrass (Dacfylis glomerata L.) and the tall fescue (Festuca arundinacea Schreb.)dominant grazing pastures, and forage plants (forages and native grasses) were sampled monthly and also K and Mg contents were determined without separating into individual plant species (Experiment 1). All the plant species grown in the two meadows which situated in the grazing pastures were harvested five times during the same period, separated into individual plant species, and botanical composition (SDR, ) and K and Mg contents of the plant species were determined (Experiment 2). The results obtained were as follows: 1. During the experimental period in the orchardgrass grazing pasture K contents of the forage plants were the highest in spring, and the seasonal variation of the contents in the orchardgrass pasture (1.5-5.8 % in a dry matter basis) was more significant than that of forage plants in the tall fescue grazing pasture (3.0- 3.8 %). 2. The Mg contents of forage plants in the orchardgrass grazing pasture ranged under 2.0 mg/g DW from Arpil until July, and the contents in the orchardgrass pasture (1.5-3.1 mg/g DW) was in the lower range than that of forage plants in the tall fescue pasture (2.0-3.8 mg/g DW). (Experiment I). 3. Orchardgrass was the dominant species in the orchardgrass meadow until July, but several species of native grasses were observed from summer (July) and native grasses such as Digitaria adscendens and Echinochlw crus-galli became dominant in autumn (October). 4. Seasonal variation of K contents of orchardgrass was in the range of 3.9-5.9 %, and the contents was higher in spring (May) and in autumn (October). The variation of white clover (Trifolium repens L.) was in the range of 3.6-5.0 %, that of tall fescue 3.8-4.8 %, and that of Italian ryegrass (Lolium multiflorum Lam.) 2.7-3.5 %, respectively. 5 . Seasonal variation of Mg content of white clover was in the range of 2.9-3.7 mg, that of tall fescue 2.0- 3.3 mg, and that of orchardgrass 1.6-2.8 mg/g DW, respectively. The variation of the contents of Italian ryegrass was in the range of 1.3-1.9 mg/g DW. And Mg contents of the forage plants were higher in summer(July) 6. In autumn (October and November ) native grasses such as D. adscendens and E. crus-galli contained lower K contents (1.7-3.9 %), but higher Mg contents (3.2-10.1 mg/g DW) than the forages contained. (Experiment 2) From the results above, it is known that K contents ranged higher in younger forages in viewpoint of growth stage and higher in spring and autumn, and that Mg contents ranged lower in spring. Therefore, the mineral imbalance or hypomagnesaemic (grass) tetany can be triggered in spring or autumn, and more frequently by such plant species as orchardgrass and Italian ryegrass with lower Mg and/or higher K contents than by tall fescue. And it is suggested that the dominant native grasses in autumn such as D. adscendens and E. emsgalli can contribute to the prevention of the tetany with higher Mg and lower K contents.

• Korean Journal of Soil Science and Fertilizer
• /
• v.31 no.2
• /
• pp.143-150
• /
• 1998

In order to evaluate the nitrogen (N) balance, from the different application methods and levels of $^{15}N$ applied to a satsuma mandarin orchard soils in spring, we surface-applied N as urea at the rates of 50 (water-dissolved), 100 (solid and water-dissolved) and 150% (solid) of the recommended rate ($180kg\;ha^{-1}$) in spring (lebeled N), summer (nonlebeled N) with application ratio of 5:2:3. Fruit yield and quality were not significantly affected by any treatment. Nitrogen contents of spring flush leaves in late August were 3.0% regardless of the treatments. The N recovery by parts of tree itself was in the order of leaves, fruits, roots, stems, and the highest recovery per tree was 22.3% in the 50% recommended water-dissolved surface broadcast while there were not much differences for N recovery (11.9 to 13.6%) among the other three treatments. Total N content in top 30cm of soils was 0.47% regardless of the treatments, but N proportion and total residual N from the fertilizer applied increased with increasing N rate while the N recovery in soils decreased. For the recommended N rate, N proportion and the residual N from the fertilizer applied were greater in the water-dissolved surface broadcast than those in soils surface broadcast. The highest total (tree + soils) N recovery was 70.9% in the 50% recommended water-dissolved surface broadcast, but tended to decrease to 52.2, 46.6, and 43.2% for the recommended water-dissolved surface broadcast, 100 and 150% of the recommended solid surface broadcast, respectively.

• Journal of the Korean Geographical Society
• /
• v.28 no.1
• /
• pp.1-15
• /
• 1993

This research aims to investigate some respects of chemical weathering processes, espcially the amount of solute leaching, formation of clay minerals, and the chemical weathering rate of granite rocks under present climatic conditions. For this purpose, I investigated geochemical mass balance in a small catchment and the mineralogical composition of weathered bedrocks including clay mineral assemblages at four res-pective sites along one slope. The geochemical mass blance for major elements of rock forming minerals was calculated from precipitation and streamwater data which are measured every week for one year. The study area is a climatically and litholo-gically homogeneous small catchment($3.62Km^2$)in Anyang-shi, Kyounggi-do, Korea. The be-drock of this area id Anyang Granite which is composed of coarse-giained, pink-colored miner-als. Main rock forming minerals are quartz, K-Feldspar, albite, and muscovite. One of the chracteristics of this granite rock is that its amount of Ca and Mg is much lower than other granite rock. The leaching pattern in the weathering profiles is in close reltion to the geochemical mass balance. Therefore the removal or accumulation of dissolved materials shows weathering patterns of granite in the Korean peninsula. Oversupplied ions into the drainage basin were $H^+$, $K^+$, Fe, and Mn, whereas $Na^2+$, $Mg^2+$, $Ca^2+$, Si, Al and $HCO-3^{-}$ were removed from the basin by the stream. The consumption of hydrogen ion in the catchment implies the hydrolysis of minerals. The surplus of $K^+$ reflects that vegetation is in the aggravation stage, and the nutrient cycle of the forest in study area did not reach a stable state. And it can be also presumed that the accumulation of $K^+$ in the top soil is related to the surplus of $K^+$. Oversupplied Fe and Mn were presumed to accumulate in soil by forming metallic oxide and hydroxide. In the opposite, the removal of $Na^+$, Si, Al resulted from the chemical weathering of albite and biotite, and the amount of removal of $Na^+$, Si, Al reflected the weathering rate of the bedrock. But $Ca^2+$ and $Mg^2+$ in stream water were contaminated by the scattered calcareous structures over the surface. Kaolinite is a stable clay mineral under the present environment by the thermodynamical analysis of the hydrogeochemical data and Tardy's Re value. But this result was quite different from the real assemblage of clay miner-als in soil and weathered bedrock. This differ-ence can be explained by the microenvironment in the weathering profile and the seasonal variation of climatic factors. There are different clay forming environments in the stydy area and these differences originate from the seasonal variation of climate, especially the flushing rate in the weathering profile. As it can be known from the results of the analysis of thermodynamic stability and characteristics of geochemical mas balance, the climate during winter and fall, when it is characterized by the low flushing rate and high solute influx, shows the environmental characteristics to from 2:1 clay minerals, such as illite, smectite, vermiculite and mixed layer clay minerals which are formed by neoformation or transformation from the primary or secondary minerals. During the summer and spring periods, kaoli-nite is a stable forming mineral. However it should consider that the other clay minerals can transformed into kaolinite or other clay minerals, because these periods have a high flushing rte and temperature. Materials which are directly regulated by chemical weathering in the weathered bedrock are $Na^+$, Si, and Al. The leaching of Al is, however, highly restricted and used to form a clay mineral, and that of Si falls under the same category. $Na^+$ is not taked up by growing veget ation, and fixed in the weathering profile by forming secondary minerals. Therefore the budget of $Na^+$ is a good indicator for the chemical weathering rate in the study area. The amount of chemical weathering of granite rocks was about 31.31g/$m^2+$/year based on $Na^+$ estimation.

• Journal of Korean Society for Atmospheric Environment
• /
• v.29 no.6
• /
• pp.818-829
• /
• 2013

The collection of rainwater samples was made at Jeju area during 2009~2010, and the major ionic species were analyzed. In the comparison of ion balance, conductivity, and acid fraction for the validation of analytical data, the correlation coefficients showed a good linear relationship within the range of 0.966~0.990. The volume-weighted mean pH and electric conductivity were 4.9 and $17.8{\mu}S/cm$, respectively, at the Jeju area. The volume-weighted mean concentrations of ionic species in rainwater were in the order of $Cl^-$ > $Na^+$ > $nss-SO_4{^{2-}}$ > $NH_4{^+}$ > $NO_3{^-}$ > $Mg^{2+}$ > $H^+$ > $nss-Ca^{2+}$ > $HCOO^-$ > $K^+$ > $PO_4{^{3-}}$ > $CH_3COO^-$ > $NO_2{^-}$ > $F^-$ > $HCO_3{^-}$ > $CH_3SO_3{^-}$. The ionic strength of rainwater was $0.26{\pm}0.21$ mM during the study period. The composition ratios of ionic species were such as 50.1% for the marine sources ($Na^+$, $Mg^{2+}$, $Cl^-$), 30.9% for the anthropogenic sources ($NH_4{^+}$, $nss-SO_4{^{2-}}$, $NO_3{^-}$), and 4.7% for the soil source ($nss-Ca^{2+}$), and 3.1% for organic acids ($HCOO^-$, $CH_3COO^-$). From the seasonal comparison, the concentrations of $NO_3{^-}$, $nss-Ca^{2+}$, and $nss-SO_4{^{2-}}$ increased in winter and spring seasons, indicating a reasonable possibility of long range transport from Asia continent. Especially, the acidifying contributions by major inorganic acids ($nss-SO_4{^{2-}}$ and $NO_3{^-}$) and organic acids ($HCOO^-$ and $CH_3COO^-$) were 87.6% and 12.4%, respectively. In comparison by sectional inflow pathway of air mass during the rainy sampling days, the concentrations of $nss-SO_4{^{2-}}$ and $NO_3{^-}$ were relatively high when the air mass was moved from the China continent into Jeju area.