• Journal of the Microelectronics and Packaging Society
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• v.25 no.4
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• pp.119-122
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• 2018

Various ZnO/Ag/ZnO multilayers were fabricated and their optical properties were investigated. Top and bottom ZnO layers were formed by sol-gel method and mid-metal layers were deposited by spin coating. To find suitable deposition condition of Ag, we measure thickness and sheet resistance of Ag monolayer. After the optimization of Ag monolayer, we fabricate ZnO/Ag/ZnO multilayers. Transmittance of ZnO/Ag/ZnO multilayers increased to 63%. In near IR region, transmittance of ZnO/Ag/ZnO multilayers decreased to 35% when the concentration of Ag solution was 2.5wt%.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.57 no.3
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• pp.256-263
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• 2021

In this study, blending oils of diesel oil and butanol were used as fuel oil for diesel engine to measure combustion pressure, fuel consumption, air ratio and exhaust gas emission due to various operating conditions such as engine revolution and torque. Using these data, the results of analyzing the engine performance, combustion characteristics and exhaust emission characteristics such as NOx (nitrogen oxides), CO₂ (carbon dioxide), CO (carbon monoxide) and soot were as follows. The fuel conversion efficiency at each load was highest when driven in the engine revolution determined by a fixed pitch propeller law. Except 30% butanol blending oil, fuel conversion efficiency of the other fuel oils increased as the load increased. Compared to diesel oil, using 10% and 20% butanol blending oil as fuel oil was advantageous in terms of thermal efficiency, but it did not have a significant impact on the reduction of exhaust gas emissions. On the other hand, future research is needed on the results of the 20% butanol blending oil showing lower or similar levels of smoke concentration and carbon monoxide emission rate other than those types of diesel oil.

• Journal of Environmental Science International
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• v.29 no.12
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• pp.1153-1170
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• 2020

With global warming and the rapid increase in urbanization accompanied by a concentration of population, the urban heat island effects (UHI) have become an important environmental issue. In this study, rooftop greening and permeable asphalt pavement were selected as measures to reduce urban heat island and applied to a simple virtual urban environment to simulate temperature change using ENVI-met. A total of five measures were tested by dividing the partial and whole area application of each measure. The results showed that the temperature range of the base experiment is 33.11-37.11 ℃, with the UTCI comfort level described as strong heat and very strong heat stress. A case applied permeable asphalt has a greater temperature difference than a rooftop greening case, the larger the area where each condition was applied, the greater the temperature change was.

• Journal of Ceramic Processing Research
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• v.19 no.5
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• pp.439-443
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• 2018

The outstanding characteristics of high quality GaN single crystal substrates make it possible to apply the manufacture of high brightness light emitting diodes and power devices. However, it is very difficult to obtain high quality GaN substrate because the process conditions are hard to control. In order to effectively control the formation of GaN polycrystals during the bulk GaN single crystal growth by the HVPE (hydride vapor phase epitaxy) method, a quartz ring was introduced in the edge of substrate. A variety of evaluating method such as high resolution X-ray diffraction, Raman spectroscopy and photoluminescence was used in order to measure the effectiveness of the quartz ring. A secondary ion mass spectroscopy was also used for evaluating the variations of impurity concentration in the resulting GaN single crystal. Through the detailed investigations, we could confirm that the introduction of a quartz ring during the GaN single crystal growth process using HVPE is a very effective strategy to obtain a high quality GaN single crystal.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.8
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• pp.421-431
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• 2021

This study investigates the empirical linkages between ASEAN countries' institutional quality and financial inclusion using country data from 2008-2019. In this paper, six governance indicators from the World Governance index are used to measure the impact of institutions on financial inclusion. The PCA method's financial inclusion index is constructed from 3 indicators: penetration, access, and usage: penetration, access, and usage with six indices respectively as the number of ATMs per 1000 km², the number of bank branches per 1000 km², the number of ATMs per 100,000 people and the number of bank branches for 100,000 adults, the ratio of credit to private to GDP, and the ratio of deposit to private to GDP. Regression analysis with the Generalized Moments method shows the positive impact of institutions and other control variables like GDP per capita, inflation, bank concentration, and human development index on financial inclusion. Therefore, this study recommends that the government and policymakers in countries pursue the financial inclusion agenda to pay attention to the financial and economic indicators and institutional factors. This is because many savers, borrowers, and investors may not be protected when financial contracts are enforced or breaches occur in an environment where economic, legal, judicial, and political institutions are weak, such as in ASEAN countries.

• Journal of the Korean Society of Visualization
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• v.20 no.2
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• pp.13-20
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• 2022

An effective capacitive deionization process termed membrane capacitive deionization (MCDI) is newly designed and experimentally tested for seawater desalination. By preventing co-ions to be expelled, MCDI can improve the ion removal performance, but there is a trade-off between blocking co-ion transfer and increasing contact resistance. The conventional MCDI uses 2D-shaped films which increase contact resistance and reduce desalination performance in the trade-off. In this paper, with the 3-D shape of Nafion coated activated carbon cloth, the mentioned problems are expected to be solved making the desalination performance better. We visualized ion concentration and fluid flows with half-MCDI cell that can measure only efficiency of cathode. We found the optimal number of coatings which have the better efficiency than CMX, commercial cation exchange membrane in fixed current conditions of 100uA.

• Membrane and Water Treatment
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• v.13 no.5
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• pp.219-225
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• 2022

5th Assessment Report of the Intergovernmental Panel on Climate Change Weather (AR5) predicts that recent severe hydrological events will affect the quality of water and increase water pollution. To analyze changes in water quality due to future climate change, input data (precipitation, average temperature, relative humidity, average wind speed, and solar radiation) were compiled into a representative concentration curve (RC), defined using 8.5. AR5 and future use are calculated based on land use. Semi-distributed emission model Calculate emissions for each target period. Meteorological factors affecting water quality (precipitation, temperature, and flow) were input into a multiple linear regression (MLR) model and an artificial neural network (ANN) to analyze the data. Extensive experimental studies of flow properties have been carried out. In addition, an Acoustic Doppler Velocity (ADV) device was used to monitor the flow of a large open channel connection in a wastewater treatment plant in Ho Chi Minh City. Observations were made along different streams at different locations and at different depths. Analysis of measurement data shows average speed profile, aspect ratio, vertical position Measure, and ratio the vertical to bottom distance for maximum speed and water depth. This result indicates that the transport effect of the compound was considered when preparing the hazard analysis.

• Journal of Sensor Science and Technology
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• v.30 no.6
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• pp.456-460
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• 2021

In this study, a Non-Dispersive Infrared (NDIR) Carbon Dioxide (CO₂) sensor with an externally exposed optical cavity is proposed for improving sensitivity. NDIR CO₂ sensors with high performance must use a lamp-type infrared (IR) source with a strong IR intensity. However, a lamp-type IR source generates high thermal energy that induces thermal noise, interfering with the accuracy of the CO₂ concentration measure. To solve this problem, the optical cavity of the NDIR CO₂ sensor is exposed to quickly dissipate heat. As a result, the proposed NDIR CO₂ sensor has a shorter warm-up time and a higher sensitivity compared to the conventional NDIR CO₂ sensor.

• Biomedical Science Letters
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• v.28 no.3
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• pp.206-210
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• 2022

Calystegia dahurica (Herb.) Choisy is a natural product that has not been studied for efficacy or active ingredients. The purpose of this study is to investigate the activation effect of natural killer cells using a natural extract composition based on Calystegia dahurica (Herb.) Choisy extract (CDCE). We evaluated the activity of natural killer cells in natural products using PBMCs from healthy participants. All natural products were extracted with 50% ethanol. Based on the results of the cell viability assay, PBMCs of healthy participants were treated with extracts at various concentrations. Then, analysis was performed using flow cytometry to measure the cd107a surface expression of natural killer cells. As a result, treatment with a single extract of PBMCs increased the expression of cd107a in a concentration-dependent. Furthermore, it was confirmed that the treatment of the extract composition showed the highest expression of cd107a. In conclusion, it is expected that the extract composition containing CDCE according to this study can be used for prevention or treatment of cancer cells, tumor cells, and immune diseases.

• Journal of the Korean Society of Visualization
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• v.21 no.1
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• pp.103-109
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• 2023

This research developed a measurement technique that can measure the oxygen temperature inside a high temperature furnace. Instead of measuring only changes in frequency components within a small range used in the existing variable laser absorption spectroscopy, laser spectroscopy technology was used to spread out wavelength of the light source passing through the gas Based on a total of 20,000 image data, research was conducted to predict the temperature of a high-temperature furnace using CNN with black and white images in the form of spectral bands by temperature of 25 to 800 degrees. The optimal model was found through Hyper parameter optimization, R2 score is 0.89, and the accuracy of the test data is 88.73%. Based on this research, it is expected that concentration measurement and air-fuel ratio control technology can be applied.