• Journal of Environmental Science International
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• 제31권12호
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• pp.999-1012
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• 2022

To investigate the reason for the spatial difference in PM_2.5 (Particulate Matter, < 2.5 ㎛) concentration despite a similar synoptic pattern, a synoptic analysis was performed. The data used for this study were the daily average PM_2.5 concentration and meteorological data observed from 2016 to 2020 in Busan and Seoul metropolitan areas. Synoptic pressure patterns associated with high PM_2.5 concentration episodes (greater than 35 ㎍/m³) were analyzed using K-means cluster analysis, based on the 900 hPa geopotential height of NCEP (National Centers for Environmental Prediction) FNL (Final analysis) data. The analysis identified three sub-groups related to high concentrations occurring only in Busan and Seoul metropolitan areas. Although the synoptic patterns of high PM_2.5 concentration episodes that occur independently in Busan and Seoul metropolitan areas were similar, there was a difference in the intensity of pressure gradient and its direction, which tends to be an important factor determining the movement time of pollutants. The spatial difference in PM_2.5 concentration in the Korean Peninsula is due to the difference and direction of the atmospheric pressure gradient that develops from southwest to northeast direction.

• Journal of Environmental Science International
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• 제21권9호
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• pp.1097-1113
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• 2012

Ozone is the secondary photochemical pollutant formed from ozone precursor such as nitrogen dioxide and non-methane volatile organic compounds(VOCs). The ambient concentration of ozone depends on several factors: sunshine intensity, atmospheric convection, the height of the thermal inversion layer, concentrations of nitrogen oxides and VOCs. Busan is located in the southeast coastal area of Korea so the ozone concentration of Busan is mainly affected from the meteorological variables related to the sea such as sea breeze. In this study the ozone concentrations of Busan in 2008~2010 were used to analyse the cause of the regional ozone difference in eastern area of Busan. The average ozone concentration of Youngsuri was highest in Busan however the average ozone concentration of Gijang was equal to the average ozone concentration of Busan in 2008~2010. The two sites are located in eastern area of Busan but the distance of two sites is only 9km. To find the reason for the difference of ozone concentration between Youngsuri and Gijang, the meteorological variables in two sites were analyzed. For the analysis of meteorological variables the atmospheric numerical model WRF(Weather Research and Forecasting) was used at the day of the maximum and minimum difference in the ozone concentration at the two sites. As a result of analysis, when the boundary layer height was lower and the sea breeze was weaker in Youngsuri, the ozone concentration of Youngsuri was high. Furthermore when the sea breeze blew from the south in the eastern area of Busan, the sea breeze at Youngsuri turned into the southeast and the intensity of sea breeze was weaker because of the mountain in the southern region of Youngsuri. In that case, the difference of ozone concentration between Youngsuri and Gijang was considerable.

• Journal of Electrochemical Science and Technology
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• 제9권2호
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• pp.99-108
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• 2018

Proton exchange membrane (PEM) water electrolysis systems offer several advantages over traditional technologies including higher energy efficiency, higher production rates, and more compact design. In this study, all the experiments were performed with a self-designed PEM electrolyser operated at 1 atm and $25^{\circ}C$. Two types of electrolyte were used: (i) potassium hydroxide (KOH), and (ii) sulfuric acid ($H_2SO_4$). In the experiments, the voltage, current, and time were measured. The concentration of the electrolyte significantly affected the electrolyser performance. Overall the best case was with 15 wt% $H_2SO_4$ at the anode channel and 20 wt% at the cathode channel with. In addition, increasing the difference in concentration of the sulfuric acid had an effect on the diffusion. The diffusion flux became larger when the difference in concentration became larger, increasing electrolyser efficiency without the addition of extra energy.

• Journal of Animal Reproduction and Biotechnology
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• 제38권3호
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• pp.121-130
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• 2023

Background: Coating a culture plate with molecules that aid in cell adhesion is a technique widely used to produce animal cell cultures. Extracellular matrix (ECM) is known for its efficiency in promoting adhesion, survival, and proliferation of adherent cells. Gelatin, a cost-effective type of ECM, is widely used in animal cell cultures including feeder-free embryonic stem (ES) cells. However, the optimal concentration of gelatin is a point of debate among researchers, with no studies having established the optimal gelatin concentration. Methods: In this study, we coated plastic plates with gelatin in a concentration-dependent manner and assessed Young's modulus using atomic force microscopy (AFM) to investigate the microstructure of the surface of each plastic plate. The adhesion, proliferation, and differentiation of the ESCs were compared and analyzed revealing differences in surface microstructure dependent on coating concentration. Results: According to AFM analysis, there was a clear difference in the microstructure of the surface according to the presence or absence of the gelatin coating, and it was confirmed that there was no difference at a concentration of 0.5% or more. ES cell also confirmed the difference in cell adhesion, proliferation, and differentiation according to the presence or absence of gelatin coating, and also it showed no difference over the concentration of 0.5%. Conclusions: The optimum gelatin-coating for the maintenance and differentiation of ES cells is 0.5%, and the gelatin concentration-mediated microenvironment and ES cell signaling are closely correlated.

• The Research Journal of the Costume Culture
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• 제10권4호
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• pp.433-440
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• 2002

Natural gardenia and Japanese pagoda tree have been known as them of the most widely used yellow vegetable dyes. Cotton and silk fabrics(KS K 0905) were chosen as specimens. Those were dyed with natural gardenia and Japanese pagoda tree. The conditions of dyeing were varied according to the kinds of mordants, using mordants or not and the concentrations of the natural dyes. Sn, Al, Fe and Cu were chosen for the mordants. 5%(owf), 10%(owf), 15%(owf) and 20%(owf) were used as for the concentration of the natural dyes. The color differences were measured by the Spectrometer(UV-VIS-NIR) before and after dyeing. The results are as follows: 1. Deeper colors were proportionately shown up to the concentration of the natural dye. 2. Silk was shown the higher dye affinity than the cotton at the same concentration of the dye. 3. The color difference between the Sn-mordanted specimens and the Al-mordanted specimens were significant. When the concentration of the dye increased, the colors got darker, specially in b* value. 4. The color difference between the Fe-mordanted specimens and the Cu-mordanted specimens were significant in L* value and b* value. 5. The deeper or lighter yellow were controllable under the concentration of the natural dye and the mordants. 6. The most effective and the economic concentration of the natural dye was 10% owf through the experiments.

• Journal of Advanced Marine Engineering and Technology
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• 제24권1호
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• pp.88-93
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• 2000

In this study, the mixing process of two-phase flow generated by two jets with height difference is analyzed. The primary jet is jetted on the condition of the state mixed pulverized solid particles with air. The height difference between the main jet and the secondary jet is changed into three kinds(0, 32.5, 47.5mm). The velocity vector field, concentration field and turbulent properties of solid particles are measured by using 3-Dimensional Particles Dynamics Analyzer. As the height difference of two jets through the two nozzles increases, the solid particle recirculation zone and the dense zone in the combustion chamber become large. The solid particle concentration at the center of the combustion chamber gets dense because the particle velocity remains slow due to the existence of the solid particle recirculation zone. The particle concentration in the combustion chamber can also be influenced by the hight difference of two jets.

• Journal of Forest and Environmental Science
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• 제32권2호
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• pp.205-211
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• 2016

Leaf chlorophyll content provides valuable information about physiological status of plants. However, fewer studies have investigated the difference in chlorophyll concentration in leaves of tropical afforestation tree species. Therefore, this study examines the difference in foliar chlorophyll contents of six tropical afforestation tree species namely: Tectona grandis, Pentaclethra macrophylla, Piptademiastrum africanum, Azadirachta indica, Brachystegia eurycoma and Gmelina arborea found in the relict forest in Umudike, South east, Nigeria. A single factor experiment in a completely randomised design in three replicates was employed to analyse the rate of leaf chlorophyll contents. Fisher's least significant different was used to test for significance in mean difference in foliar chlorophyll contents between tree species at 95% confidence interval using analysis of variance. The results of this study showed a significant difference in foliar chlorophyll concentration between the tree species with Tectona grandis having a higher chlorophyll concentration than other trees this could be as a result of its higher vegetative activity which increases its primary productivity followed by Pentaclethra macrophylla while Azadirachta indica having least the chlorophyll concentration. The study further revealed that other indigenous tree species like Piptademiastrum africanum and Brachystegia eurycoma have higher chlorophyll concentration. Further studies should be carry out to examine factors that have contributed informed the differences in the chlorophyll concentration of these trees species, thus this would broaden the understanding of their physiological status and equally encourage there conservation.

• Journal of environmental and Sanitary engineering
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• 제8권2호
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• pp.149-154
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• 1993

Authors investigated on the content of tin metals in 108 samples of tinplated canned fruit commercial. 1. The highest concentration of tin in 11 kinds of samples of canned fruit that is, apricot nectar was 114ppm and lowest of that 2.5∼3ppm. 2. There was 48.6ppm of tin content in orange nectar A that of pineapple nectar 56.6ppm in higher remarkably and that of the other samples was no appearance difference. 3. There was 114ppm(number 10), 5.3∼56.6ppm(number 8) and 8.7∼48.6ppm(number 3) of tin content in minimum between maximum concentration for difference remarkably and that of others there was no difference considerably, The highest concentration in detection frequency of content range was 8∼ 14ppm in 41. 7% and 2.5"6.6ppm in 36.1% and that of concentration was lower for comparison the others. 5. There was lower contration of tin in all samples for law of food hygiene in limitation 150ppm.

• Journal of Environmental Health Sciences
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• 제17권2호
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• pp.127-139
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• 1991

Four group(Control I II, Treatment I II ) of Rats, each consisting of 10 rats, were studied Methylmercury Chloride MMc was orally given to Sprague-Dawley male at does of 10mg/kg (5 mg/kg $\cdot$ day), 10mg/kg after two weeks. This study was designed to investigate the distribution, the difference and the ratio of organic mercury, total mercury, zinc and copper in tissue, in each others group. The result were as follows: 1. There was no significantly difference in the body weight between two groups( p > 0.05). 2. There was significantly difference in the distribution of zinc concentration in liver, kidndey, blood, spleen between control I and treatment I, and in blood, spleen between control II and treatment II (P < 0.05). 3. There was significantly difference in the distribution of copper concentration in kidney, blood between control I and treatment I, and in spleen brain between control II and treatment II. 4. The ratio of zinc concentration in treatment/control was high at spleen. 5. The ratio of methylmercury/totalmercury was high at spleen.

• Korean Journal of Food Science and Technology
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• 제33권3호
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• pp.294-300
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• 2001

Effect of bean water concentration and incubation time of Yukwa paste as well as packaging method on the quality of Yukwa was investigated. Quality loss in Yukwa during storage was dependent on the packaging method such as bamboo packaging at $30^{\circ}C$, nitrogen packaging at $30^{\circ}C$ and LDPE packaging at $-18^{\circ}C$. Peroxide value increased with bean water concentration, but showed no significant difference by incubation time. The hardness of Yukwa decreased with the increase of bean water concentration, incubation time, and storage time but showed no significant difference by packaging method. Sensory evaluation after storage for 3 months showed that Yukwa color was significantly influenced by packaging method and bean water concentration. The volume was also significantly influenced by bean water concentration and incubation time. Off-flavor showed significant difference by storage method. Tenderness, taste and overall desirability showed significant difference by bean water concentration. Crispness showed significant difference by storage method and bean water concentration.