• Journal of Space Technology and Applications
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• v.1 no.3
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• pp.356-363
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• 2021

It was common knowledge in textbooks that images acquired using mid-infrared ray were not suitable for measuring temperature near room temperature. But a recent satellite image using a mid-infrared sensor show the possibility that the result measured using the mid-infrared sensor can also measure the temperature near room temperature. In this paper, the possibility and accuracy of extraction room temperature information from satellite images with mid-infrared sensors are reviewed. The mid-infrared satellite image reviewed in this paper showed the temperature of room temperature well, and regarding the reliability as an absolute value of the measured temperature, the effect of the heat transfer amount due to the direct reflection of sunlight on the surface and the effect of the infrared absorption amount absorbed in the atmosphere can be seen as a relatively small or constant value. However, the problem of uncertainty in the radiation coefficient due to physical properties, which is the limit of the non-contact thermometer, remained a problem to be solved.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.3
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• pp.285-292
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• 2022

The objective of this study is to investigate whether CGS generated in IGCC satisfies the fine aggregate quality items specified in KS F 2527(Concrete Aggregate) through the pretreatment process system and the quality improvement the system. The statistical significance of the pretreatment process was analyzed through Repeated Measurements ANOVA as measured values according to individually pretreatment process system. As a result of the analysis, In the case of CGS fine aggregate quality before and after the pretreatment process system, the density increased 5.2 %, the absorption rate decreased by 1.86 %, the 0.08 mm passing ratio decreased by 2.25 %, and Fineness Modulus and Particle-size Distribution were also found to be adjustable. It was found that the pretreatment process system was significant in improving the quality of CGS.

• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3841-3848
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• 2022

The effect of modifiers on the optical features and radiation defying ability of the Eu³⁺ ions doped multi constituent glasses was examined. XRD has established the amorphous nature of the specimen. The presence of various functional/fundamental groups in the present glasses was analyzed through FTIR spectra. The physical, structural and elastic traits of the glasses were explored. The variation in the structural compactness of the glass structure according to the incorporated modifier was enlightened to describe their suitability for a better shielding media. For the examined glasses, the metallization criterion value varied in the range 0.613-0.692, indicating the non-metallic character of the glasses with possible nonlinear optical applications. The computed elastic moduli expose the Li-containing glass (BTLi:Eu) to be tightly packed and rigid, which is a requirement for a better shielding channel. Furthermore, the optical bandgap and the Urbach energy values are calculated based on the optical absorption spectra. The evaluated bonding parameters revealed the nature of the fabricated glasses covalent. In addition, we investigated the radiation attenuation attributes of the prepared Eu³⁺ ions doped multi constituent glasses using Phy-X software. We determined the linear attenuation coefficient (LAC) and reported the influence of the five oxides Li₂O₃, CaO, BaO, SrO, and ZnO on the LAC values. The LAC varied between 0.433 and 0.549 cm^-1 at 0.284 MeV. The 39B₂O₃-25TeO₂-15Li₂O₃-10Na₂O-10K₂O-1Eu₂O₃ glass has a much smaller LAC than the other glasses.

• Journal of the Korean Wood Science and Technology
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• v.31 no.5
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• pp.80-87
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• 2003

This research was carried out to examine physical and mechanical properties of clay-woodceramics which were carbonized for 3 hours in a special furnace from 3 layers-clay-woodparticleboard made from pallet waste wood, phenol formaldehyde resin(hereafter PF, Non volatile content 52%, resin content 30%) and clay(10%, 20% and 30%). Carbonization temperature was 400℃, 600℃ and 800℃. The results are summarized as follows: 1. The higher the carbonization temperature, the higher the dimensional shrinkage and the lower the carbonization yield ratio. But the higher the clay addition, the lower the dimensional shrinkage and the higher carbonization yield ratio. 2. The higher the carbonization temperature, the higher the water absorption and the density. The higher the clay content, the higher the density. 3. The higher the carbonization temperature, the higher the bending Modulus of Rupture and bending Modulus of Elasticity.

• Journal of Adhesion and Interface
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• v.23 no.2
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• pp.39-43
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• 2022

In optoelectronic devices including displays and solar cells that convert electricity into light or light into electricity, it is important to control optical behavior of light to improve device efficiency. Specifically, the control of internal emitting light in the OLEDs can induce more light to go out, improving luminous efficiency. In addition, the control of optical behavior of incident light in solar cells can increase optical path in the light absorption layer, increasing power-conversion efficiency. In this study, we generated wrinkles as a physical structure to control optical behavior of light and independently controlled their wavelength and height by changing stress relaxation time. To explore the effect of wavelength and height on optical behavior, we conducted UV/Vis spectroscopy analysis of wrinkles with various heights at a constant wavelength or various wavelengths at a comparable height, figuring out a wrinkle with high aspect ratio has more dispersive light and less straight light. It indicates that high aspect ratio is required to change the optical behavior and increase the optical path.

• Journal of Conservation Science
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• v.38 no.4
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• pp.301-313
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• 2022

We made a Korean white porcelain or Joseon Baekja jar and based on the raw materials used and reproductions of each stage, we aimed to compare and analyze the physicochemical changes of the raw materials such as clay at each manufacturing stage, as well as identify the characteristics and correlations. Although the basic main components of clay and glaze material are similar, their texture becomes denser in the process of bisque firing pottery (Chobeol-pyeon) and glaze firing pottery (Jaebeol-pyeon), and we confirmed that in addition to the tendency of increasing vitrification, low-temperature minerals such as mica and illite gradually disappeared, while high-temperature minerals such as cristobalite were newly created. This phenomenon has also been verified by the rapid decrease in absorption rate while the change in specific gravity was small. In addition, the color was greatly affected by the firing atmosphere, and the yellow-red chromaticity of the raw materials was higher during bisque firing but showed a rapidly decreasing characteristic during glaze firing. The value of magnetic susceptibility, which is related to iron (Fe) component, showed a tendency to decrease in glaze firing pottery. CT images were confirmed as a method that can indirectly estimate the change in the material properties of the object step-by-step for the entire object. In conclusion, the study of manufacturing stages of reproduction can provide basic data for scientific research on the estimation of porcelain and pottery making technology and changes in raw materials.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.s01
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• pp.1-17
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• 1988

Rice Quality is considered to the five catagories ; the nutritional value: the characteristics of cooking. eating and processing: grain size, shape and appearance : milling yields: and storage characteristics. Because most rice is processed and consumed in whole-kernel form. the cooking and eating quality is of important and the physical properties of the intact kernel such as size, shape and general appearance are of particular significance in determining marketing quality. Eating Quality which can be directly evaluated by consumer's panel test is so complicate and variable, and thus the objective and simplified method of evaluation is required of using appropriate instruments. Even though many researches have been done to evaluate the eating quality in various aspects such as the texture of cooked rice kernels, amylogram analysis of rice powder, amylose content. gelatinization temperature. moisture absorption of rice kernel, and cooking characteristics, none of them is satisfied for the evaluation of eating quality. The improving eating quality should be also considered to many cultural factors. such as varieties, climatic and soil conditions, cultural method, handling after harvest. milling and storage conditions. In Korea, many researches in grain size. shape and appearance, and eating quality have been done with the varietal improvement mainly by rice breeders, but no effective method of evaluation was established. A few research have been done in the relationship between rice quality and cultural factors. In the future, research in rice quality should emphasize to establish the standard evaluation method in the physicochemical properties of rice kernels for application of varietal selection. and to develop cultural practices for the preserving quality characteristics of the varieties.

• Advances in concrete construction
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• v.14 no.3
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• pp.205-214
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• 2022

Due to seawater's physical and chemical deterioration effects on concrete structures, it is crucial to investigate the durability of these structures in marine environments. In some conditions, concrete structures are exposed to seawater from the first days of construction or because of the lack of potable water, part of the concrete curing stage is done with seawater. In this research, the effects of exposure to seawater after 7 days of curing in standard conditions were evaluated. To improve the durability of concrete, fly ash has been used as a substitute for a part of the cement in the mixing design. For this purpose, 5, 15, and 30% of the mixing design cement were replaced with type F fly ash, and the samples were examined after curing in seawater. The resistance of concrete against chloride ion penetration based on the rapid chloride penetration test (RCPT), water permeability based on the depth of water penetration under pressure, and water absorption test was done. The changes in the compressive strength of concrete in different curing conditions were also investigated. The results show that the curing in seawater has slightly reduced concrete resistance to chloride ion permeation. In the long-term, samples containing FA cured in seawater had up to 10% less resistance to chloride ion penetration. The amount of reduction in chloride ion penetration resistance was more for samples without FA. Whiles, for both curing conditions in the long-term up to 15%, FA improved the chloride ion penetration resistance up to 40%. Curing in seawater slightly increased the penetration depth of water under pressure in samples containing FA, while this increase was up to 12% for samples without FA. In the long-term the compressive strength of samples cured in seawater is not much different from the compressive strength of samples cured in plain water, while at the age of 28 days, due to seawater salts' accelerating effects the difference is more noticeable.

• Journal of Forest and Environmental Science
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• v.39 no.1
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• pp.55-64
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• 2023

Properties of a lesser-used wood species were investigated to determine its potential for structural utilization. Trees of Delonix regia were felled and sampled at the base, middle and top and then sectioned to inner wood, middle wood, and outer wood for variation across the axial and radial directions. Hence, selected physical and mechanical properties as well as natural durability of D. regia along the radial and axial directions were examined. Obtained data were analyzed using analysis of variance (ANOVA) at α_0.05. There was no significant difference in the Moisture content (MC) of the wood but specific gravity (SG) decreased from base to top ranging from 0.35-0.44. Water absorption, volumetric swelling, and volumetric shrinkage range from 46.18-51.86%, 2.57-4.02%, and 2.26-3.96% respectively along the axial plane. The weight loss for graveyard exposure and accelerated laboratory decay test ranged from 25.14-48.00% and 32.02-44.45% respectively. Modulus of Rupture and Modulus of Elasticity values range from 29.42-72.68 Nmm² and 3,834.54-8,830.37 Nmm² respectively. The SG values has confirmed the species as a medium density wood and values of other properties tested showed that the wood is dimensional stable and moderately resistance to fungi and termite. Hence, it could be used for light construction purposes such as furniture and other interior woodwork.

• Journal of the Korean institute of surface engineering
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• v.56 no.3
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• pp.208-218
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• 2023

Photocatalysts are advanced materials which accelerate the photoreaction by providing ordinary reactions with other pathways. The catalysts have various advantages, such as low-cost, low operating temperature and pressure, and long-term use. They are applied to environmental and energy field, including the air and water purification, water splitting for hydrogen production, sterilization and self-cleaning surfaces. However, commercial photocatalysts only absorb ultraviolet light between 100 and 400 nm of wavelength which comprises only 5% in sunlight due to the wide band gap. In addition, rapid recombination of electron-hole pairs reduces the photocatalytic performance. Recently, studies on blackening photocatalysts by laser, thermal, and plasma treatments have been conducted to enhance the absorption of visible light and photocatalytic activity. The disordered structures could yield mid-gap states and vacancies could cause charge carrier trapping. Herein, liquid phase plasma (LPP) is adopted to synthesize Ag-doped black ZnO for the utilization of visible-light. The physical and chemical characteristics of the synthesized photocatalysts are analyzed by SEM/EDS, XRD, XPS and the optical properties of them are investigated using UV/Vis DRS and PL analyses. Lastly, the photocatalytic activity was evaluated using methylene blue as a pollutant.