• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1078-1086
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• 1996

The peroxo-polytungstic acid was formed by the direct reaction of tungsten powder with the hydrogen peroxide solution. Peroxo-polytungstic powder were prepared by rotary evaporator using the fabricated on to ITO coated glass as substrate by dip-coating method using $2g/10mL(W-IPA/H_2O)$ sol solution. A substrate was dipped into the sol solution and after a meniscus had settled, the substrate was withdrawn at a constant rate of the 3mm/sec. Thicker layer could be built up by repeated dipping/post-treatment 15 times cycles. The layers dried at the temperature of $65{\sim}70^{\circ}C$ during the withdrawn process, and then tungsten oxides thin film was formed by final heating treatment at the temperature of $230{\sim}240^{\circ}C$ for 30min. A linear rotation between the thickness of thin film and the number of dipping/post-treatment cycles for tungsten oxides thin films made by dip-coating was found. The thickness of thin film had $60{\AA}$ after one dipping. From the patterns of XRD, the structure of tungsten oxides thin film identified as amorphous one and from the photographs of SEM, the defects and the moderate cracks were observed on the tungsten oxides thin film, but the homogeneous surface of thin films were mostly appeared. The electrochemical characteristic of the $ITO/WO_3$ thin film electrode were confirmed by the cyclic voltammetry and the cathodic Tafel polaization method. The coloring bleaching processes were clearly repeated up to several hundreds cycles by multiple cyclic voltammetry, but the dissolved phenomenon of thin film revealed in $H_2SO_4$ solution was observed due to the decrease of the current densities. The diffusion coefficient was calculated from irreversible Randles-Sevick equation from the data obtained by the cyclic voltammetry with various scan rates.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.3
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• pp.55-61
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• 2018

This study evaluated if the selected samples meets the Solid Refuse Fuel quality criteria in Korea. Biomass and plastic wastes generated in D City were mixed in diverse ratio. When the biomass content was about 40%, the moisture content was close to the SRF criteria and was measured to be 9.8%. The ash contents were analyzed up to 4.19%, and the lower calorific values based on Steuer, Dulong Equation and Bomb Calorimeter were at least 4,851, 4,181 and 3,847 kcal/kg, respectively. As a result of the elemental analysis, sulfur and chloride content were measured up to 0.05%. Those values satisfied the SRF criteria. Also, heavy metals(Hg, Cd, Pb, As) were analyzed to be below the SRF criteria. This makes it possible to use efficiently the wood byproducts abandoned in the woods, and the physical properties of wood being weak to moisture can be supplemented with plastics. Consequently, if plastic and biomass were well mixed and made into SRF, it would overcome the problem of shortening the life span of incineration facilities due to the high temperature of plastic wastes in the incinerator.

• Journal of the Korea Convergence Society
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• v.8 no.9
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• pp.127-133
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• 2017

The purpose of this study is to confirm the effect of natural tooth whitening using fruits that can be easily accessed in real life by increasing interest in tooth whitening in modern society. Twenty premolar teeth were divided into five groups (n=4). Strawberry (A), lemon (B), banana skin (C), baking soda (D) and whitening toothpaste (E) were treated with a toothbrush on the enamel surface. The tooth surface was treated with a toothbrush at the same time for 3 minutes for breakfast, lunch, and dinner, then washed with sterile distilled water, and stored in saline solution. This procedure was repeated for 4 weeks, and the color change of teeth was observed at intervals of one week. After 4 weeks, there was a significant difference in tooth color change after 3 weeks(p<0.05). Among them, strawberry and lemon showed higer effects to whitening toothpaste. It is believed that strawberries and lemons have a higher whitening effect than whitening toothpaste. Whitening toothpaste may be replaced with a safe natural whitening effect using strawberries and lemons instead of chemical ingredients that may be harmful to human body.

• Journal of Environmental Science International
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• v.24 no.12
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• pp.1559-1567
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• 2015

This study investigated the association between $PM_{2.5}$ concentrations obtained with portable real-time monitors and those obtained with gravimetric methods in national urban air-quality monitoring sites in Seoul, South Korea. We used the SidePak AM510 Personal Aerosol Monitor (TSI Inc., 500 Cardigan Road Shoreview, MN) and DustTrak DRX 8533 (TSI Inc., 500 Cardigan Road Shoreview, MN) as portable real-time monitors for measuring $PM_{2.5}$ concentrations and compared these values with those measured with the PMS-103 or SEQ 47/50 models operated by Federal Reference Method (FRM) or the European Committee for Standardization(ECS), respectively, in national urban air-quality monitoring sites in Seoul. Measurements were conducted every other day in the winter and spring seasons of 2014. The estimated daily mean concentrations of $PM_{2.5}$ ranged between 13.4 and $161.9{\mu}g/m^3$ using AM 510 and between 22.0 and $156.0{\mu}g/m^3$ using DustTrak. The Spearman correlation coefficient for $PM_{2.5}$ concentrations between AM 510 and gravimetric results was 0.99, and the correlation between DustTrak and gravimetric results was 0.87. The correction factor suggested was 0.42 and 0.29 for AM 510 and DustTrak, respectively. We found that $PM_{2.5}$ concentrations measured with real-time monitors could overestimate true $PM_{2.5}$ concentrations and therefore the application of a correction factor (0.43) is strongly suggested for quantification when Real-time monitors were operated of $PM_{2.5}$ levels at urban atmospheric environment of South Korea.

• Journal of radiological science and technology
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• v.37 no.3
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• pp.233-238
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• 2014

The amount of environmental radiation was measured in the indoor(basement) and outdoor(rooftop) of the two buildings of the University (the old building and the new building) in Suwon City, Gyeonggi Province. Measuring the environmental radiation dose from the first week of April 2013 to last week of March 2014, Twice a week, one year. The measured results were as follows. 1. The average annual environmental radiation of the two buildings were $0.169727{\mu}Sv/hr$. The lowest value was $0.0760{\mu}Sv/hr$ whereas the highest value was $0.3000{\mu}Sv/hr$. 2. The amount of environmental radiation dose was $0.176373999{\mu}Sv/hr$ in the old building and the amount of environmental radiation dose was $0.163052885{\mu}Sv/hr$ in the new building. The old building environmental radiation dose was higher then the new building. 3. The month of the lowest amount of environmental radiation dose in a year was November resulting in $0.152844{\mu}Sv/hr$ whereas May was found the month of the highest amount of environmental radiation dose showing with $0.197222{\mu}Sv/hr$. 4. The amount of environmental radiation dose in the indoor(basement) was $0.164649{\mu}Sv/hr$ and the amount of environmental radiation dose of the outdoor(rooftop) was $0.174779{\mu}Sv/hr$. And the outdoor(rooftop) was higher than the indoor(basement). 5. Depending on seasonal, the lowest amount of environmental radiation dose was in winter with $0.1632{\mu}Sv/hr$ while spring was the season with the highest amount of environmental radiation dose with $0.183846{\mu}Sv/hr$. The measured amount was high in the order of spring, summer, autumn, and winter.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.9
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• pp.409-415
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• 2014

Ground-source heat pump (GSHP) systems have become an efficient alternative to conventional cooling and heating methods due to their higher energy efficiency. These systems use the ground as a heat source and the heat sink for cooling mode operation. The purpose of this simulation study is to evaluate the performance of a hypothetical GSHP system in an office building and to assess the energy saving effect against the existing HVAC systems (boiler and turbo chiller). We collected monthly energy consumption data from an actual office building ($32,488m^2$) in Seoul, and created a model to calculate the hourly building loads with EnergyPlus. In addition, we used GLD (Ground Loop Design) V8.0, a GSHP system design and simulation software tool, to evaluate hourly and monthly performance of the GSHP system. The energy consumption for the GSHP system based on the hourly simulation results were estimated to be 582.6 MWh/year for cooling and 593.2 MWh/year for heating, while those for the existing HVAC systems were found to be 674.5 MWh/year and 2,496.4 MWh/year, respectively. The seasonal performance factor (SPF) of the GSHP system was also calculated to be in the range of 3.37~4.28.

• Genomics & Informatics
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• v.7 no.4
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• pp.195-202
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• 2009

BIRC5 (Survivin) belongs to the inhibitor of apoptosis gene family. The BIRC5 protein inhibits caspases and consequently blocks apoptosis. Thus, BIRC5 contributes to the progression of cancer allowing for continued cell proliferation and survival. In this study, we identified eight sequence variants of BIRC5 through direct DNA sequencing. Among the eight single nucleotide polymorphisms (SNPs), six common variants with frequencies higher than 0.05 were selected for larger-scale genotyping (n=1,066). Results of the study did not show any association between the promoter region polymorphisms and the clearance of hepatitis B virus (HBV) infection and hepatocellular carcinoma (HCC) occurrence. This is in line with a previous study in which polymorphisms in the promoter region does not influence the function of BIRC5. Initially, we were able to detect a signal with the ＋9194A>G, which disappeared after multiple corrections but led to a change in amino acid. Similarly, we were also able to detect an association signal between two haplotypes (haplotype-2 and haplotype-5) on the onset age of HCC and/or HCC occurrence, but the signals also disappeared after multiple corrections. As a result, we concluded that there was no association between BIRC5 polymorphisms and the clearance HBV infection and/or HCC occurrence. However, our results might useful to future studies.

• Genomics & Informatics
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• v.7 no.4
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• pp.187-194
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• 2009

Cytochrome P450 2E1 (CYP2E1) is a member of the cytochrome P450 superfamily, and it is a key enzyme responsible for the metabolic activation of many smallmolecular-weight compounds such as alcohol, which is classified as a human carcinogen. In this study, we identified 19 single nucleotide polymorphisms (SNPs) in CYP2E1 in Korean population. In these SNPs, we examined possible genetic association of CYP2E1 polymorphisms with HBV clearance and the risk of hepatocellular carcinoma (HCC). Five common polymorphic sites were selected, CYP2E1 polymorphisms at rs381-3867, rs3813870, rs2070673, rs2515641 and rs2480257, considering their allele frequencies, haplotype-tagging status and LDs for genotyping in larger-scale subjects (n=1,092). Statistical analysis demonstrated that CYP2E1 polymorphisms and haplotypes show no significant association with HBV clearance, HCC occurrence and onset age of HCC (p>0.05). Previous studies, however, have shown contradictory findings on associations of CYP2E1 polymorphisms with CYP2E1 activities and HCC risk. Comparing the contrasting results of previous researches suggest that CYP2E1 polymorphism is associated with CYP2E1 activity induced by ethanol, but is not directly associated with HCC risk. CYP2E1 variation/haploype information identified in this study will provide valuable information for future studies on CYP2E1.

• Anatomy and Cell Biology
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• v.49 no.2
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• pp.143-150
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• 2016

Understanding of morphological structures such as the sphenoid spine and pterygoid processes is important during lateral transzygomatic infratemporal fossa approach. In addition, osseous variations such as pterygospinous and pterygoalar bridges are significant in clinical practice because they can produce various neurological disturbances or block the passage of a needle into the trigeminal ganglion through the foramen ovale. Two hundred and eighty-four sides of Korean adult dry skulls were observed to carry out morphometric analysis of the lateral plate of the pterygoid process, to investigate, for the first time among Koreans, the incidence of the pterygospinous and pterygoalar bony bridges, to compare the results with those available for other regional populations, and to discuss their clinical relevance as described on literatures. The mean of maximum widths of the left and right lateral plates of the pterygoid process were 15.99 mm and 16.27 mm, respectively. Also, the mean of maximum heights of the left and right lateral plates were 31.02 mm and 31.01 mm, respectively. The ossified pterygospinous ligament was observed in 51 sides of the skulls (28.0%). Ossification of the pterygospinous ligament was complete in four sides (1.4%). In 47 sides (16.6%), the pterygospinous bridge was incomplete. The ossified pterygoalar ligament was observed in 24 sides of the skulls (8.4%). Ossification was complete in eight sides (2.8%) and incomplete in 16 sides (5.6%). This detailed analysis of the lateral plate of the pterygoid process and related ossification of ligaments can improve the understanding of complex clinical neuralgias associated with this region.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.6
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• pp.63-69
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• 2018

The machine learning model can capture the dynamics of building systems with less inputs than the first principle based simulation model. The training data for developing a machine learning model are usually selected in a heuristic manner. In this study, the authors developed a machine learning model which can describe supply air temperature from an AHU in a real office building. For rational reduction of the training data, the progressive sampling method was used. It is found that even though the progressive sampling requires far less training data (n=60) than the offline regular sampling (n=1,799), the MBEs of both models are similar (2.6% vs. 5.4%). In addition, for the update of the machine learning model, the normalized mutual information (NMI) was applied. If the NMI between the simulation output and the measured data is less than 0.2, the model has to be updated. By the use of the NMI, the model can perform better prediction ($5.4%{\rightarrow}1.3%$).