• Journal of Adhesion and Interface
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• v.20 no.1
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• pp.1-8
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• 2019

Fabrication of monolayer is important method for enhancing physical and chemical characteristics such as light shielding and antireflection while maintaining thin film properties. In previous studies, monolayers were fabricated by various methods on small substrates, but processes were complicated and difficult to form monolayers with large area. We used rod coating equipment with a small amount of coating liquid to form a HCP (hexagonal closed packing) coating of PMMA beads on PET(poly(ethylene terephthalate)) substrate with $20cm{\times}20cm$ size. We observed that changes in morphologies of monolayers by using the solvents with different boiling points and vapor pressures, by adapting surfactants on particles and by applying plasma treatment on substrates. The coverage was increased by 20% by optimizing the coating conditions including meniscus of beads, control of the attraction - repulsion forces and surface energy. This result can potentially be applied to optical films and sensors because it is possible to make a uniform and large-scale monolayer in a simple and rapid manner when it is compared to the methods in previous studies.

• The Korean Journal of Archival Studies
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• no.49
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• pp.213-246
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• 2016

On Kawara's works are not only artworks but are also his personal daily records. He produced many artworks whose theme centered on his everyday life, a plan that he had precisely made. He selected several specific themes from his daily life: when and where he met someone, what he read, and where he traveled. Kawara constantly recorded his daily life using various types of unconventional medium: maps, postcards, and telegrams. Although he was occupied with recording his everyday life, he was also active in forming public opinions on various issues through social media. Kawara's works, which exhibit a distinctive characteristic of himself, could be classified as individual records because it includes an individual's daily life and selected issues. His artworks express concern for or expose the irrationality of his society, which encourages ordinary people to let their voices be heard and take part in public affairs. Thus, his works function not just as art but also as precious historical records.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.2
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• pp.145-151
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• 2021

When manufacturing Alaska pollack Gadus chalcogrammus surimi for 3D printing, it examined the characteristics of physical properties and sensuality by adding polysaccharides alginic acid [0, 1, 2, 3% (w/w)]. As a result of the color value of surimi by adding alginic acid, it showed that the lightness of heated surimi containing 2% (w/w) alginic acid was the highest and ∆E value was the lowest. In the changes in physical properties, the heated surimi of 3% (w/w) alginic acid content showed the lowest values of hardness, springiness, cohesiveness, gumminess, chewiness and resilience, but the highest adhesiveness. In the case of fried surimi, its hardness, cohesiveness, gumminess, chewiness and resilience were the lowest at the content of 3% (w/w) alginic acid. After 7 days of cold storage, the hardness, gumminess, and chewiness of heated surimi with an alginic acid content of 2% (w/w) were significantly higher, and fried surimi was also the same. In the results of the sensory evaluation, there were significant differences according to the alginic acid content in hardness and fishy smell, and as the alginic acid content increased, it felt more fishy smell, resulting in poor preference.

• Korean Journal of Optics and Photonics
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• v.32 no.5
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• pp.209-214
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• 2021

High-power continuous-wave operation of a Yb-doped double-clad fiber laser at 1018 nm, pumped by high-power diode lasers at 976 nm, is reported. Based on numerical calculation of the gain and laser signal power along the length of the Yb fiber, it is found that robust operation at 1018 nm can be achieved for a high Yb³⁺-ion excitation density greater than 11.5%, accompanied by high suppression of the feedback from the fiber's end facet. The Yb fiber laser constructed in house yields 626 W of continuous-wave output at 1018 nm for 729 W of incident pump power, corresponding to a slope efficiency of 86.6%. The prospect for power scaling is considered.

• Resources Recycling
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• v.29 no.6
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• pp.15-26
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• 2020

In recent years, there is an increasing interest in environmental friendly treatment of waste-plastics in terms of the generation of microplastics. Accordingly, the recycling of waste-plastics is very important because it provides advantages of volume reduction, mitigation of carbon dioxide emission, and reproduction of value-added products. In particular, in order to recycle the eco-friendly waste-plastics, it is necessary to use a physical separation methods, and among them, flotation separation, which can separate material (i.e., polymer component) in waste-plastics is well known as a very effective separation method in terms of material recycle. Therefore, in this review, the research trend of flotation separation for effective separation of mixture waste-plastics was investigated. In addition, through the reported research results, approaches to use as new functional materials from polymers, which are raw materials for waste-plastics, are summarized.

• Journal of Korea Foundry Society
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• v.41 no.3
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• pp.235-240
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• 2021

We present the effect of the critical cooling rate during rapid solidification on the nucleation of precipitates in an Fe₇₅B₁₃P₅Nb₂Hf₁C₄ (at.%) alloy. The thermophysical properties of the rapidly solidified Fe₇₅B₁₃P₅Nb₂Hf₁C₄ liquids, which were obtained at various cooling rates with various sizes of gas-atomized powder during a high-pressure inert gas-atomization process, were evaluated. The cooling rate of the small-particle powder (≤20 ㎛) was 8.4×10⁵ K/s, which was 13.5 times faster than that of the large-particle powder (20 to 45 mm; 6.2×10⁴ K/s) under an atomized temperature. A thermodynamic calculation model used to predict the nucleation of the precipitates was confirmed by the microstructural observation of MC-type carbide in the Fe₇₅B₁₃P₅Nb₂Hf₁C₄ alloy. The primary carbide phase was only formed in the large-particle gas-atomized powder obtained during solidification at a slow cooling rate compared to that of the small-particle powder.

• Korean Journal of Veterinary Service
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• v.44 no.2
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• pp.93-102
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• 2021

In this study, a total of 9,449 hard ticks were collected once a month from April to October 2020 from a neighborhood park in Daejeon by flagging & dragging method and CO₂ manned trap method. The collected ticks were classified according to the Yamagutsi search table using a stereoscopic microscope and molecular biological analysis of four pathogens (SFTSV, Anaplasma spp., Ehrlichia spp., Borrellia spp.). As a result of the study, Haemaphysalis longicornis were collected the most in all areas of the five boroughs at a rate of 82 to 96 percent, while adults were collected the most in May to July, nymphs were collected the most in April to June, and larvae from August to October at a rate of 78 percent to 98 percent. In pathogens, three cases of SFTSV were detected, showing a minimum infection rate (MIR) of 0.46%, while Anaplasma spp. and Ehrlichia spp. were detected one each, with 0.15% and Borrelia spp. with a minimum infection rate of 0.46%. The detected SFTSV showed 99.9% homogeneity with the KF781490 detected in Cheongwon-gun, Chungbuk Province, Anaplasma spp. showed 99.0% homogeneity with JN990105 detected in China, and Erhlichia spp. showed 98.9% genetic similarity with U96436 separated from the U.S. In this study, the distribution status and pathogen infection rate of the hard ticks in the Daejeon area are analyzed and provided as basic data for the prevention of the hard tick-borne infectious disease.

• Korean Journal of Otorhinolaryngology-Head and Neck Surgery
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• v.60 no.10
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• pp.504-511
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• 2017

Background and Objectives In this study, we evaluated differences in the prevalence of allergic rhinitis, asthma, atopic dermatitis and specific immunoglobuline E (IgE) value for some respiratory antigens in Korean adults. Subjects and Method The study was conducted using data from the 5th National Health and Nutrition Survey (2010-2012). All subjects who were aged 19 years or older completed questionnaires on asthma, atopic dermatitis and allergic rhinitis. The subjects were first divided into male and female, and then into age groups of 19-29, 30-39, 40-49, 50-59, 60-69, ${\geq}70$ each. The lifetime and current prevalence rates for allergic rhinitis, asthma, and atopic dermatitis were calculated for each age group. The total and specific IgE level for Dermatophagoides farinae (DF), cockroach, and dog dander were also calculated. Results Final participants of 17542 were analyzed for the prevalence rate among the total of 25534 participants. The mean IgE level was calculated from 2028 subjects from the final participants. In asthma, the lifetime prevalence and current prevalence increased with age, but decreased with atopic dermatitis and allergic rhinitis. Total IgE level increased with age, but IgE level of DF reached its peak at 20-29 years, and then decreased rapidly thereafter. There was no clear trend for cockroach and dog dander. Conclusion The prevalence of allergic diseases in adults varies widely by age group. Asthma has a low prevalence after age 20 and gradually increases after age 50. Atopic dermatitis and allergic rhinitis are the most prevalent in their 20s and gradually decrease thereafter.

• Korean Journal of Ecology and Environment
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• v.53 no.4
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• pp.355-364
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• 2020

This study was carried out to investigated changes in sediments in the eight weir sections of Nakdong River. Sediments were collected and analyzed for Grain Size, Ignition loss, Total Organic Carbon, Total Nitrogen, Total Phosphorus, and Meta. The upstream of the weir was found that fine-grained sediments have repeated increases and decreases. It was found that coarse-grained sediments were being maintained in the downstream part of the weir. The sediments Ignition Loss, Total Organic Carbon, Total Nitrogen, Total Phosphorus are strongly correlated with Grain Size, and these increased at the point where sediments are fine. In the case of metal, the concentration increased across the board, and the correlation with Grain Size, Ignition loss, Total Organic Carbon, Total Nitrogen, and Total Phosphorus was weak. Although there were some sections where fine-grained sediments, organic materials, nutrients, metals increased in the Nakdong River, the overall pollution level is considered weak.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.2
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• pp.218-223
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• 2021

In this study, the possibility of use as a cartridge for 3D printing was confirmed by adding calcium to the alginic acid-added surimi mixture. The Alaska pollack Gadus chalcogrammus surimi added with alginic acid was immersed in a calcium solution (1 M calcium carbonate, 1 M calcium chloride, 1 M calcium sulfate, and 0.1 M calcium lactate) to evaluate the physical properties, color differences, and sensory properties of Alaska pollack surimi according to calcium types. As the results, in the case of surimi paste to which 1 M calcium carbonate was added, physical properties were weaker than that of 1 M calcium chloride, but gelation was appropriate and sensory properties was excellent. Addition of 1 M calcium chloride has the best physical properties, but it has a problem of bitter taste. With the addition of 1 M calcium sulfate, it has low solubility and poor physical properties as well as poor elasticity and bad taste. Addition of 0.1 M calcium lactate has weak physical properties but good sensory properties. From these results, 1 M calcium chloride has the best physical properties, but there is a decisive problem in sensory properties, so 1 M calcium carbonate is most suitable for commercial use.