• Journal of the Semiconductor & Display Technology
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• v.18 no.1
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• pp.105-111
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• 2019

The TADF (Thermally Activated Delayed Fluorescence)-based OLED patents were analyzed and 4410 of patents were selected at the first step. And 975 patents were screened at second step. Finally, 39 key patents were selected. Patent qualitative analysis was performed in these patents to find which of the four property (lifetime, efficiency, color purity, driving voltage) of TADF was improved. Also, the variation of the hosts and dopants in patented TADF material were surveyed and their combination was analyzed. According to the analysis of the variation and the combination, some of TADF compounds were used as an assistant dopant to transfer energy. In addition, it tended to transfer energy by forming exciplex that shows TADF characteristics. These were similar to the mechanism of the introduced hyper fluorescence and could solve the inherent TADF problems. Finally, patent citation network was illustrated to visualize the patent citations and citations relationship of the major applicants in the current TADF-based OLED technology. The leading patent applicant organization was revealed as Idemitsu Kosan, Semiconductor Energy Laboratory, UDC, Princeton University, Merck and Nippon Steel & Sumikin Chemical, which had lots of reference patents 559, 524, 477, 310, 258, and 167, respectively.

• Textile Coloration and Finishing
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• v.33 no.3
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• pp.131-140
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• 2021

Collagen and chitosan are used in medical and cosmetic materials as natural polymers. In order to utilize the advantages of the materials, collagen/chitosan conjugated wet-spun fibers were prepared. The analysis of surface, optical, thermal and mechanical properties was carried out on the various composition of collagen and chitosan. As a result of images analysis, it was verified that the collagen/chitosan conjugated fibers were stably spun. In addition, the optical and thermal properties of fibers were observed to be changed by hydrogen bond. As a result, an optimized composition could be found at an appropriate content. Moreover, the optimized fibers have mechanical properties similar to chitosan fibers, while improving the structural and thermal stability by its hydrogen bond. In addition, the wet-spun collagen/chitosan conjugated fibers can be applied to medical and various fields through mechanical properties according to content control.

• International journal of advanced smart convergence
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• v.10 no.3
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• pp.225-231
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• 2021

In the search for another appealing source of future food to cover the increasing need for nutrients of a growing global population, this study reviewed the potential of insects as human food. This study assessed some common edible insects, but concentrated on mealworms. Insects, especially mealworms, have a similar or higher nutritional value than many conventional food sources. The present study aimed to promote health through the development of blueberry cake by Mealworm Powder (Tenebrio molitor Lavare). The results of Sensory evaluation comparison of Blueberry cake to different levels of mealworm powder. The sensory evaluation showed that sample 3 had the highest color, taste, texture, and overall texture except flavour. Therefore, mealworm blueberry cake made with 60g of mealworm powder showed the best results. The results of analyzing the general components of the Mealworm blueberry cake showed more than two times higher Crude protein and less than half Crude fat compared to control blueberry cake. It is believed that the addition of mealworm powder means that the protein in the cake, a high carbohydrate food, has been strengthened. This is the development of bakery products with both nutritional excellence and symbolism, and it is believed that wheat worm powder is a good food material as a favorite food, not a hateful food, which will improve consumer awareness of edible insects.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.12
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• pp.49-55
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• 2020

In order to improve the electromagnetic shielding rate of Carbon Fiber (CF), it was produced using the nickel nano-powder impregnating method. Using two types of nickel powder having thicknesses of 50 ㎛ and 100 ㎛, and a thermoplastic elastomer resin, a compound containing 10-20% nickel content was mixed and then manufactured through an extruder. The CF coated with the compound was woven and manufactured using a 1-ply specimen. The final nickel content of the specimen was verified using TGA and the distribution of nickel powder on the CF surface was verified using SEM. The metal shows a high shielding rate in the low-frequency band, but the shielding rate decreases at higher-frequency bands. The CF improves at the higher frequency band, and metals reflect electromagnetic waves while carbon absorbs electromagnetic waves. The study of shielding materials, which are stronger and lighter than metal, by using CF lighter than metal and enabling the shielding rate from low-frequency band to high-frequency band, confirmed that the larger the area coated with nickel nano-powder, the better the electromagnetic shielding performance. In particular, CF coated with a thickness of 100 ㎛ has a shielding rate similar to that of copper and can also be used for EV/HEV automotive cables and other applications in the future.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.8
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• pp.59-67
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• 2018

In a state where ancient buildings was left a lot in the case of Korea, many parts do not remain the documentation, and there is a Kiwarisho lot in Japan, however, the present methods and tree split does not exist in the Korea. However, it is impossible to make a perfect building without splitting exact member when making a building. Thus will not be revealed simply by presumption that there is a similar way to wood comparatively far in Korea. Without a comparison of building dimensions and Korea calculation dimensions Kiwarisho In the first study about the proportionality of Korea, I do not know until now, other studies of the following documents which house a high approximation ratio and member size of Korea consider reason to have is impossible. View compared with respect to the axis of the building in the early stages of research first. In the case of Japan and Korea to form a tree frames in basic form that form the building, the shaft portion is easy to understand and easy compared in common is at most the shaft portion.

• Journal of Surface Science and Engineering
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• v.55 no.6
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• pp.376-382
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• 2022

Yb₂Si₂O₇ has a coefficient of thermal expansion similar to that of the base material of SiC and has excellent corrosion resistance in a high-temperature oxidizing atmosphere including water vapor, so it is being studied as one of the materials for environmental barrier coatings (EBCs). In this study, Yb₂Si₂O₇ powder granule is deposited using atmospheric plasma spraying (APS) with different Ar/He ratios. Phase formation and microstructural characteristics are investigated with the coated specimens. In the coating layer, the crystallinity decreased, and the amorphous content increased from an increase in the ratio of Ar. In addition, the various types of particles involved by local volatilization of Si according to the Ar/He ratios were identified.

• Advances in concrete construction
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• v.10 no.6
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• pp.515-526
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• 2020

Cold-mixed asphalt mixture is a widely recommended asphalt pavement materials with potentially economic and environmental benefits. Due to the reduction of natural non-renewable mineral resources, powder minerals with similar properties are considered as new mineral fillers in asphalt mixtures. This study explored the feasibility of using cement to replace natural limestone powder (LP) in emulsified asphalt concrete modified by styrene-butadiene styrene copolymer. The experimental tests, including compressive strength, Marshall stability as well as moisture susceptibility test, were used to investigate the mechanical properties, the Marshall stability, flow value, as well as the moisture damage. In addition, the influence of material composition on the performance of asphalt concrete is explained by the microstructure evolution of the pore structure, the interface transition zone (ITZ), and the micromorphology. Due to mineralogical reactivity of cement, its replacement part of LP improved the mechanical properties, Marshall stability, but it will reduce the moisture susceptibility and flow value. This is because with the increase of the cement substitution rate, the pore structure of the asphalt concrete is refined, the width of ITZ becomes smaller, and the microstructure is more compact. In addition, asphalt concrete with a larger nominal particle size (AC-16) has relatively better performance.

• Advances in concrete construction
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• v.11 no.5
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• pp.409-417
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• 2021

The incorporation of non-biodegradable tyre waste in cement-based material has gained more interest towards sustainable construction these days. Crumb rubber (CR) from waste tyre is an alternative for sand replacement in low strength applications. Many researchers have studied CR cement-based materials produced by normal mixing (NM) method and reported a significant decrease in compressive strength due to CR. To compensate this strength loss, this research aims to study the innovative incorporation of CR in cement composite via the preplaced mixing (PM) method. In this investigation, cement composite was produced with NM and PM methods by replacing sand with 0%, 50%, and 100% CR by volume. The test results showed no significant difference in terms of densities of cement composite prepared with both mixing methods. However, cement composite prepared with PM method had lower strength reduction (about 10%) and lowered drying shrinkage (about 20%). In addition, the sound absorption coefficient and noise reduction coefficient of CR cement composite prepared by PM method were in similar range as those prepared with NM method. Overall, the results demonstrate that the PM method is promising, and the maximum replacement level of 50% is recommended for CR in the cement composite.

• Journal of the Korean Physical Society
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• v.73 no.11
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• pp.1716-1724
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• 2018

Single crystal of organic lead halide ($CH_3NH_3PbX_3$; $CH_3NH^+_3$ = methylammonium (MA), $X=Cl^-$, $Br^-$, $I^-$) is the best candidate for material intrinsic property studies due to no grain boundary and high crystal quality than the film having a lot of grain boundary and surface defects. The representative crystallization methods are inverse temperature crystallization (ITC) and anti-solvent vapor assisted crystallization (AVC). Herein, we report bandgap modulated organic lead halide single crystals having a bandgap ranging from ~ 2.1 eV to ~ 3 eV with ITC and AVC methods. The bandgap modulation was achieved by controlling the solvents and chloride-to-bromide ratio. Structural, optical and compositional properties of prepared crystals were characterized. The results show that the crystals synthesized by the two crystallization methods have similar properties, but the halide ratios in the crystals synthesized by the AVC method are controlled more quantitatively than the crystals synthesized by ITC.

• Korean Journal of Metals and Materials
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• v.48 no.5
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• pp.410-416
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• 2010

Studies were carried out to establish the technology for sodium-clad compatibility and to analyze the compatibility behavior of the Sodium-cooled Fast Reactor (SFR) cladding material under a flowing sodium environment. The natural circulation facility caused by the thermal convection of the liquid sodium was constructed and the 316-series stainless steels were exposed at $650{^{\circ}C}$ liquid sodium for 1458 hours. The weight change and related microstructural change were analyzed. The results showed that the quasi-dynamic facility represented by the natural convection exhibited similar results compared to the conventional dynamic facility. Selective leaching and local depletion of the chromium, re-distribution of the carbide, and the decarburization process took place in the 316-series stainless steel under a flowing sodium environment. This process decreased as the sodium flowed along the channel, which was caused by the change in the dissolved oxygen and carbon activity in the liquid sodium.