• Journal of Applied Biological Chemistry
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• 제64권1호
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• pp.1-4
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• 2021

Ambient air pollution, in particular, particulate matter (PM) pollution imposes serious health concerns such as hospitalization and premature deaths, worldwide. While commercial breathing masks are in use for protection against this hazardous issue, yet their efficiency in filtering PM was not up to the par, besides several other discomforts such as poor breathability due to reduced air flow, sweat production etc. In this study, commercial face mask coated with β-glucan, a high molecular weight polymer is tested for its efficacy in filtering PM. Quantification of PM before and after filtration and microscopic observation (using scanning electron microscopy (SEM)) of the fabric used in filtering the dust pollutants (generated from wood chips and cigarette) showed that β-glucan coated fabric were significantly efficient in capturing PM (size of 10 and 2.5 ㎛ in diameter) than that of the untreated control fabric, wherein the former had filtration efficacy with fold increase of 11.6 and 2.6 towards capturing PM2.5 and PM10 respectively than the latter. Thus, β-glucan coated fabric was found to be effective in filtering PM.

• The Bulletin of The Korean Astronomical Society
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• 제44권2호
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• pp.52.2-52.2
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• 2019

In the last decades, the use of type Ia supernovae (SN) as standard candles has allowed us to understand the geometry of the Universe as they help to measure the expansion rate of the Universe, especially in combination with other cosmological probes such as the study of cosmic microwave background radiation anisotropies or the study of the imprint of baryonic acoustic oscillations on the galaxy clustering. Cosmological parameter constraints obtained with type Ia SN are mainly affected by intrinsic systematic errors. But there are other systematic effects related with the correlation of the observed brightness of Supernova and the large-scale structure of the Universe such as the effect of peculiar velocities and gravitational lensing. The former is relevant for SN at low redshifts while the latter starts being relevant for SN at higher redshifts. Gravitational lensing depends on how much matter is along the trajectory of each SN light beam. In order to account for this effect, we consider a statistical approach by defining the probability distribution (PDF) that a given supernova brightness is magnified by a given amount, for a particular redshift. We will show that different theoretical approaches to define the matter density along the light trajectory hugely affect the shape and width of the PDF. This may have catastrophic effects on cosmology fits using Supernova lensing as planned for surveys such as the Dark Energy Survey or future surveys such the Large Synoptic Survey Telescope.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국정보통신학회 2021년도 추계학술대회
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• pp.348-350
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• 2021

When predicting the concentration of fine dust using deep learning, there is a problem that the characteristics of a high concentration of 81㎍/m³ or more are not well reflected in the prediction model. In this paper, a comparison through predictive performance was conducted to confirm the results of reflecting the characteristics of fine dust in the high concentration area according to the deep learning algorithm. As a result of performance evaluation, overall, similar levels of results were shown, but the RNN model showed higher accuracy than other models at concentrations of "very bad" based on AQI. This confirmed that the RNN algorithm reflected the characteristics of the high concentration better than the DNN and LSTM algorithms.

• Applied Microscopy
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• 제26권2호
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• pp.243-252
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• 1996

The somata and boutons of the zinc-containing neurons in the spinal cord of the rats were labeled by intraperitoneal injection of sodium selenite and silver amplification. The labeled somata of the neurons were located in laminae V, VI, VII and X of the gray matter. The zinc selenium reaction products were retrogradely transported and precipitated into somata of the neuron with survival 8 hours. This observation suggest that all or part of the spinal cord zinc-containing neurons are interneurons. At survival 1 hour, the loaded axonal boutons with zinc precipitates of zinc-containing neurons were distributed in the gray matter and in the processes of lateral and ventral funiculi of the white matter. In particular, AMG stained boutons with huge form were appeared in the lamina IX. Ultrastructurally, the zinc precipitates were located in the cytoplasmic lysosomes or the vesicle within boutons of the zinc-containing neuron in accordance with survival times.

• Journal of Environmental Science International
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• 제22권12호
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• pp.1643-1650
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• 2013

This study investigated water quality of effluents and stream from the sewage treatment plants located at Gumi Complex 4, Gumi, and Wonpyeong in Gumi. Downstream region was found to increase the concentration of nutrients for sewage treatment plant effluent. Both phosphorus and nitrogen were accounted most as soluble form. In particular, the high ratio of dissolved effluent of sewage treatment plants were investigated. In the streams, Phosphorus concentration was high during rainy season and nitrogen concentration was high in the dry season. Sewage treatment plant effluent was relatively less microbial activity and nutrient concentrations were higher in the winter. TN/TP ratio was the highest in the upstream region and the lowest in the sewage treatment plant effluent. The effect of the nutrient matter from a discharge of a sewage treatment plant on rivers varied depending on the size of the river and the treatment plant. However, the influence of the concentration was greater than that of flowrate. Sewage treatment plant effluent loads phosphorus, nitrogen accounted for 8% and 6% respectively at the point N3 of the Nakdong river.

• Journal of the Korean Chemical Society
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• 제47권3호
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• pp.265-272
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• 2003

This study investigated the types of analogies that 7th graders generated to explain three states of matter, the difference of analogies by achievement level, and the misconceptions that might be induced from the analogies. The results revealed that many students made the enriched and storytelling analogies with concrete materials or events from their everyday experiences. However, they made analogies without considering causal relationship such as the change of particular arrangement based on latent heat or molecular movement. The students of high achievement level considered the arrangement and the movement of molecules and made the enriched and storytelling analogies more than the students of low achievement level. The students made the analogies that might induce misconceptions such that the molecules don't move in solid state or the particles could be changed according to the states.

• Journal of the Korean School Mathematics Society
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• 제14권2호
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• pp.123-142
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• 2011

Recently, a number of researches acknowledge the importance of 'reflection' and 'reflective teacher education,' and they highlight the implication of 'reflection' on the teacher's profession or the teacher education. The reflective thought is interpreted as a subject that should be taught or a sort of strategy that a teacher should learn, while the aspect is excluded that reflection is the interaction between the innate knowledge and the practice. As a result, the reflective teacher education programs that increase the level of reflection are developed and practiced, and the reflection is accepted as a tool for increasing teacher professionalism. Reflective teaching is en essential and basic element for the development of teacher knowledge. In particular, such teacher knowledge might be being gradually expanded by a teacher's self-assessment on reflection on his own instruction. For this reason, this study develops an assessment framework on instruction which is comprized of teacher knowledge and instructional process. To accomplish this, in this study, teacher knowledge is considered as a whole practice knowledge combined by subject matter knowledge, understanding of learners, teaching and learning methods and assessment, and instructional environment. Also, success on instruction in mathematics class might depend on the acquisition of teacher knowledge, instructional planning, instructional execution, and furthermore reflection on instruction. Especially, this study emphasizes that 'reflection on instruction', the most important step of instruction be reflected and examined by the teacher himself.

• Horticultural Science & Technology
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• 제34권6호
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• pp.807-817
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• 2016

Many onion growers and researchers assert that differences in soil type, agricultural practices, weather, and duration of prolonged onion cultivation in a particular field could affect onion bulb quality. This study evaluates the bulb quality of onions grown in different regions and determines the correlations between bulb characteristics and postharvest loss during cold and ambient storage. Soil and onion bulbs were collected from fields in six onion growing regions in Korea, during the growing season of 2011-2012. The fresh weight, dry matter content, and carbon (C), sulfur and magnesium contents of the onion bulbs were significantly affected by the location in which they were grown. Bulbs grown in Muan had the greatest number of scales, thinnest scale thickness, and the highest total soluble solids (TSS) and total flavonoids (TF). Bulbs originating from Jecheon had the lowest pyruvic acid (PA), total phenolics and TF. Storage loss of bulbs from the different regions was similar in refrigerated storage, but differed in ambient temperature storage. Bulb fresh weight was positively correlated with scale thickness (r = 0.617) and cold storage loss (CSL; r = 0.398). Dry matter content was positively correlated with C (r = 0.958) and TF (r = 0.256) contents, while it was negatively correlated with CSL (r = -0.424). CSL was primarily affected by the fresh weight, as well as the dry matter, C, and PA contents of the bulbs, while ambient storage loss was primarily influenced by the amount of TSS.

• Elastomers and Composites
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• 제56권4호
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• pp.234-242
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• 2021

The demand for truck bus radial (TBR) tires with enhanced fuel efficiency and wear resistance have grown in recent years. In addition, as the issue of particulate matter and air pollution increases, efforts are being made to reduce the generation of particulate matter. In this study, the properties of epoxidized natural rubber (ENR) containing a silica-friendly functional group were evaluated by considering it as a base rubber and varying the silica ratio in this binary filler system. The results showed that the wear resistance of the NR/BR blend compound decreased as the silica ratio increased. In contrast, the ENR/BR blend compound exhibited an increase in wear resistance as the silica ratio was increased. In particular, the ENR-50/BR blend compound showed the best wear resistance due to the presence of several epoxide groups. Furthermore, we observed that for tan 𝛿 at 60℃, higher epoxide content resulted in the higher T_g of the rubber, indicating a higher tan 𝛿 at 60℃. On the other hand, it was confirmed that increasing the silica ratio decreased the value of tan 𝛿 at 60℃ in all compounds. In addition, we measured the amount of wear particulate matters generated from the compound wear. These measurements confirmed that in the binary filler system, regardless of the filler type, the quantity of the generated wear particulate matters as the filler-rubber interaction increased. In conclusion, the silica filled ENR/BR blend compound exhibited the lowest generation of wear particulate matters.

• The Journal of the Korea Contents Association
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• 제22권6호
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• pp.1-14
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• 2022

This study aims to identify topics in newspaper articles related to fine particle matter and to investigate the characteristics and time series trend of each topic. Related national newspaper articles during 1990 and 2021 were collected from Bigkinds. A total of 18 topics have been discovered using LDA, and 11 clusters deduced from clustering. Hot topics include related products/residence, overseas cause(China), power plant as a domestic cause, nationwide emergency reduction measures, international cooperation, political issues, current situation & countermeasure in other countries, and consumption patterns. Cold topics include the concentration standard and indoor air quality improvement. These findings would be useful in inferring the political direction and strategies. In particular, the consumer protection policy should be expanded as the related market is growing. It will also be necessary to pursue policies that will promote public safety and health, and that will enhance public consensus and international cooperation.