• Korean Journal of Ecology and Environment
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• v.51 no.4
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• pp.253-258
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• 2018

Phytoplankton community was studied in relation to a typhoon at Bok-gyo Bridge area in Juam Lake, Korea. In August 31, 2000, a typhoon (Prapiroon) was passed by Juam Lake with great power enough to destroy summer stratification of Juam Lake. Destratification resulted in temporal mixing of the whole water column and changed the physical and chemical properties of water bodies, and caused the changes of the biological properties. The transparency decreased from 195 cm before the typhoon to 84 cm after the typhoon with the resuspension of the bottom sediment. In the vertical distribution of the phytoplankton population, the maximum population was measured at depth of 2 m before the typhoon. However, immediately after the typhoon, the population distributed evenly throughout the entire water layers. The carbon biomass of the phytoplankton was also highest at the depth of 2 m before the typhoon, but immediately after the typhoon, it was uniformly distributed throughout the whole water layers. The vertical profiles of the concentrations of chlorophyll a, however, did not show a significant difference before and after the typhoon. The typhoon induced destratification and restratification altered the taxa of the phytoplankton. The major dominant phytoplankton taxa before the typhoon was diatoms including Aulacoseira granulata, but the green algae overwhelmed the diatoms in cell number and biomass after the typhoon. The chlorophycean dominance was replaced by cyanophycean dominance with the heavy rain and descent of water temperture at the end of September.

• Journal of Convergence for Information Technology
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• v.9 no.6
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• pp.218-226
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• 2019

In this study, we investigated the possibility of Kaempferia Galanga(KG) hot water extract on the antioxidant, cytotoxic and anti-inflammatory efficacy as a cosmetic ingredient. Antioxidant effects were evaluated based on DPPH and ABTS radical scavenging activity, FRAP assay, and total polyphenol contents. The MTT assay was used to confirm the cell toxicity in mouse macrophage RAW264.7 cells. Anti-inflammatory effects were also investigated in LPS-induced RAW264.7 cells by measuring secretion of NO, $TNF-{\alpha}$ and iNOS, $TNF-{\alpha}$ mRNA expression level. As a result, DPPH and ABTS radical scavenging activities were increased in a concentration-dependent manner. The ferric reducing antioxidant power(FRAP) was the highest at 5 mg/mL as 24.5 uM. The measurements of total polyphenol content was $1.28{\pm}0.064mg\;GAE/g$. The cytotoxicity of the KG extract results showed no cytotoxicity at concentration of 0.625 to 2.5 mg/mL. In addition, the extract of KG significantly suppressed the LPS-induced nitrite, $TNF-{\alpha}$ secretion and the mRNA expression of iNOS, $TNF-{\alpha}$ in RAW264.7 cells. Taken together, these data suggest that the KG hot water extracts can be used as a safe and functional cosmetic raw material.

• Journal of Drive and Control
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• v.17 no.4
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• pp.133-140
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• 2020

Traction performance of a tractor varies depending on soil conditions. Sinkage and slip of the driving wheel for tractor frequently occur in a reclaimed land. The objective of this study was to develop a tractor suitable for a reclaimed land. Traction performance was evaluated according to soil conditions of reclaimed land and paddy field. Field experiments were conducted at two test sites (Fields A: paddy field; and Field B: reclaimed land). The tractor load measurement system was composed of an axle rotation speed sensor, a torque meter, a six-component load cell, GPS, and a DAQ (Data Acquisition System). Soil properties including soil texture, water content, cone index, and electrical conductivity (EC) were measured. Referring to previous researches, the tractor traveling speed was set to B3 (7.05 km/h), which was frequently used in ridge plow tillage. Soil moisture contents were 33.2% and 48.6% in fields A and B, respectively. Cone index was 2.1 times higher in field A than in field B. When working in the reclaimed land, slip ratios were about 10.5% and 33.1% for fields A and B, respectively. The engine load was used almost 100% of all tractors under the two field conditions. Traction powers were 31.9 kW and 24.2 kW for fields A and B, respectively. Tractive efficiencies were 83.3% and 54.4% for fields A and B, respectively. As soil moisture increased by 16.4%, the tractive efficiency was lowered by about 28.9%. Traction performance of tractor was significantly different according to soil conditions of fields A and B. Therefore, it is necessary to improve the traction performance of tractor for smooth operations in all soil conditions including a reclaimed land by reflecting data of this study.

• Clean Technology
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• v.27 no.1
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• pp.85-92
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• 2021

A solar water battery is a system that generates power using solar energy. It is a combination of photoelectrochemical cells and an energy storage system. It can simultaneously convert and store solar energy without additional external voltage. Solar water batteries consist of photoelectrodes, storage electrodes and counter electrodes, and their properties and combination are important for the performance and the efficiency of the system. In this study, we tried to find the effect that changing the components of solar water batteries has on its system. The effects of the counter electrode during discharge, the kinds of photoelectrode and storage electrode materials, and electrolytes on the solar energy conversion and storage capacitance were studied. The optimized composition (TiO2 : NaFe-PB : Pt foil) exhibited 72.393 mAh g-1 of discharge capacity after 15 h of photocharging. It indicates that the efficiency of solar energy conversion and storage is largely affected by the configuration of the system. Also, the addition of organic pollutants to the chamber of the photoelectrode improved the battery's photo-current and discharge capacity by efficient photoelectron-hole pair separation with simultaneous degradation of organic pollutants. Solar water batteries are a new eco-friendly solar energy conversion and storage system that does not require additional external voltages. It is also expected to be used for water treatment that utilizes solar energy.

• Journal of the Korean Society of Radiology
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• v.15 no.4
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• pp.429-435
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• 2021

In intracavitary radiotherapy, incorrect location of the source can cause excessive dose to normal tissue, so it is essential to evaluate the location accuracy of the source. In this study, basic research was performed on digital line dosimeter based on lead (II) oxide (PbO) to improve analog verification method. Therefore, a polycrystalline PbO unit cell dosimeter was manufactured and the measurement performance for Ir-192 sources was evaluated. As a result, the reproducibility satisfies the evaluation criteria of 1.5% with a relative standard deviation of 0.85%. Linearity showed excellent results with a linear coefficient of R² of 0.9998. In the case of distance dependence evaluation, the power function R² showed 0.9855 for PbO and 0.9974 for diode, and the overall average difference was 1.66% for PbO and 2.18% for diode. This study presents the basic detection performance of the polycrystalline PbO dosimeter for the Ir-192 source and can provide basic data in the field of radiation measurement.

• Journal of Mushroom
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• v.19 no.4
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• pp.322-328
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• 2021

This study was carried out to evaluate potential of Hypsizygus marmoreus (brown cultivar) as a functional food and drug materials. H. marmoreus were divided into pileus and stipe and extracted in hot water and 80% ethanol. The total polyphenol content was highest in the hot water extracts (pileus 17.15±0.19 mg of GAE g, stipe 7.37±0.16 mg of GAE/g) and pileus compared to the ethanol extracts (pileus 10.23±0.14 mg of GAE/g, stipe 3.76.±0.19 mg of GAE/g) and stipe. Also, hot water extracts of pileus from H. marmoreus (brown cultivar) was more effective DPPH, ABTS, ORAC value, reducing power than ethanol extracts and stipe extracts. The pileus and stipe extracts were confirmed to be non-cytotoxic in the mouse macrophage cell line RAW 264.7 determined by WST-1 (4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulphonate) assay. Overall, extracts of H. marmoreus (brown cultivar) was higher antioxidant activity than other mushrooms, and no cytotoxicity. Therefore, H. marmoreus (brown cultivar) showed potential as a functional food and drug materials. The brown cultivar of H. marmoreus have higher antioxidant activity than white cultivar, H. marmoreus seem to have different antioxidant activity depending on the cultivar.

• Korean Journal of Clinical Laboratory Science
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• v.55 no.2
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• pp.82-92
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• 2023

Urine sediments are performed by a microscopic examination of centrifuged urine by medical technologists. This study examined different urine sediment preparation procedures. The 107 fresh urine specimens that tested positive from white blood cells (WBCs) and red blood cells (RBCs) in the urine dipstick test and the cobas u 701 analyzer, respectively, were selected for manual microscopy. This study evaluated an automated urine sediment analyzer and three manual microscopy methods for WBCs and RBCs. The methods were performed according to the test guidelines. The coefficients of determination between the cobas u 701 analyzer and the Korean Association of Quality Assurance for Clinical Laboratory (KAQACL) for WBCs and RBCs were r2=0.977 and r2=0.970, respectively. The concordance rates between the cobas u 701 analyzer and KAQACL for WBCs and RBCs were 74.8% and 77.6%, respectively. A good correlation and concordance with the automatic analyzer were shown when the specimens were prepared and examined using the KAQACL method. Consequently, the differences in the urine sediment preparation procedures affected the sediment concentrations, influencing the cell number per high power field (HPF).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.1
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• pp.63-69
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• 2023

'Carbon-neutrality Assessment based on Technology Application Scenario (CATAS)' provides an analysis of greenhouse gas (GHG) reduction effectiveness when applying carbon-neutrality technology to areas such as energy conversion, transportation, and buildings at certain spatial levels. As for the development scope of the model, GHG emission sources were analyzed for direct GHG emissions, and the boundary between direct and indirect emissions are set according to the spatial scope. The technical scope included nine technologies and forest sinks in the transition sector that occupies the largest portion of GHG emissions in the 2050 carbon neutral scenario. The carbon neutrality rate evaluation methodology consists of four steps: ① analysis of GHG emissions, ② prediction of energy production according to technology introduction, ③ calculation of GHG reduction, and ④ calculation of carbon neutrality rate. After the web-based CATAS-BASIC was developed, an analysis was conducted by applying the new and renewable energy distribution goals presented in the ｢2050 Greenhouse Gas Reduction Promotion Plan｣ of the Seoul Metropolitan Government. As a result of applying solar power, hydrogen fuel cell, and hydrothermal, the introduction of technology reduced 0.43 million tCO₂eq of 1.49 million tCO₂eq, which is the amount of emissions from the conversion sector in Seoul, and the carbon neutrality rate in the conversion sector was analyzed to be 28.94 %.

• Journal of IKEEE
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• v.27 no.4
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• pp.644-649
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• 2023

As the cell spacing decreases during the scaling process of DRAM(Dynamic Random Access Memory), the reduction in STI(Shallow Trench Isolation) thickness leads to an increase in sub-threshold leakage due to the passing word line effect. The increase in sub-threshold leakage current caused by the voltage applied to adjacent passing word lines affects the data retention time and increases the number of refresh operations, thereby contributing to higher power consumption in DRAM. In this paper, we identify the causes of the passing word line effect through TCAD Simulation. As a result, we confirm the DRAM operational conditions under which the passing word line effect occurs, and observe that this effect alters the proportion of the total leakage current attributable to different causes. Through this, we recognize the necessity to consider not only leakage currents due to GIDL(Gate Induced Drain Leakage) but also sub-threshold leakage currents, providing guidance for improving DRAM structure.

• Journal of Life Science
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• v.34 no.5
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• pp.296-303
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• 2024

Vinegar is a fermented food product created by fermenting various sugar- and starch-containing ingredients with microorganisms. It contains a variety of organic acids, sugars, amino acids, esters, and other compounds that contribute to its unique sensory properties. Vinegar is known for its potential benefits, including aiding digestion, lowering blood sugar levels, anti-obesity effects, and antioxidant properties. It is also believed to contribute to improving alkaline body conditions. This study was conducted to develop functional dried vinegar powder from naturally fermented vinegars. Unripe apple, brown rice, and black chokeberry (aronia) were fermented using Gluconacetobacter xylinus for 90-180 days. The filtrate vinegar was spray dried with 37.46% maltodextrin, 5% glucose, 1% citric acid, and 0.04% vitamin C. Analysis of the acidity, color difference, water and soluble solid content, and heat stability of dried vinegar (DV) confirmed that spray drying is a suitable method for powder production. Moreover, the DVs exhibited excellent sensory attributes and solubility. Among the DVs, aronia-DV showed the highest 1,1-diphenyl-2-picryl hydrazyl and 2,2-azobis (3- ethylbenzothiazoline-6-sulfonate) radical scavenging activity (36.7% and 75.3%) and reducing power (0.334) at 0.5 mg/ml concentration, respectively. The nitrite scavenging activity was highest in brown unripe apple-DV, followed by aronia-DV and brown rice-DV. In the anti-thrombosis activity assay, aronia-DV showed the highest prothrombin inhibition. The brown rice-DV exhibited lipid accumulation inhibitory activity in 3T3-L1 adipocytes without cell cytotoxicity. Our results suggest the potential for commercialization of dried vinegar, highlighting its diverse benefits and applications.