• Composites Research
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• v.34 no.2
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• pp.108-114
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• 2021

Graphene flakes are generally mass-produced by converting graphene oxide into reduced graphene oxide using chemical or thermal reduction. These graphene flakes can be stacked to form a free-standing graphene paper, which can be used for various applications. However, a graphene paper lacks stretchability, which hinders its application in stretchable devices. In this work, we introduced wrinkles in a graphene paper to make it stretchable. A graphene paper fabricated by vacuum-filtering a graphene dispersion was placed on a pre-stretched adhesive film. When the pre-stretched adhesive film returned to the original state, the graphene paper was wrinkled. The effect of the pre-stretching and wet condition of the graphene papers was experimentally investigated by using scanning electron microscopy. In addition, we observed the change of the period of the wrinkles in the graphene paper depending on the pre-stretching.

• Fashion & Textile Research Journal
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• v.23 no.6
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• pp.826-835
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• 2021

The purpose of this study was to compare the similarity between actual and virtual pants using a virtual 3D CLO program. A subject corresponding to the average size of a women in her twenties was selected and an avatar with the same specifications was produced. Silhouettes of the pants were classified into trousers, slacks, and wide pants and images of actual and virtual pants were evaluated from the front, side, and back. The results were as follows: Overall, the resemblance of the trousers was evaluated higher than that of other pants. The average similarity of trousers was 4.20 at the front, 3.98 at the side, and 4.17 at the back, which was much like the actual clothing. In contrast, that of the slacks was 3.62, 3.73, and 3.79 and of the wide pants was 3.81, 3.53, and 3.97. The similarity between the actual and virtual clothing was relatively well reproduced when the shape of the pants was like the silhouette of the human body. However, if the pants were tight or loose, virtual fits failed to display the wrinkles caused by the tightness or the excessive slack. The virtual fit showed fewer wrinkles and did not depict the location and the shape of hemlines as accurately as the actual fit, although virtual fits adequately displayed the baseline and dart on the pants.

• 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.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.36 no.4
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• pp.113-121
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• 2023

Objectives : The purpose of this study is to analyze the treatment mechanism of Thread-embedding acupuncture, which is used in Korean medicine beauty treatment. Methods : After searching papers published up to January 1, 2023 using the keyword "Thread-embedding" through the OASIS site, we selected beauty papers that mentioned the treatment mechanism of Thread-embedding acupuncture. Results : A total of 60 papers were retrieved: 19 papers on the topic of cosmetic diseases, 35 papers on the theme of other diseases, and 6 papers written unrelated to diseases. Among the 19 papers on the topic of cosmetic diseases, one unreadable paper was excluded. Among the 18 papers, we finally selected 6 papers that mentioned treatment mechanisms: 2 on facial wrinkles, 2 on obesity, 1 on breast enlargement, and 1 on transdermal hydration. The treatment mechanism of Thread-embedding acupuncture is that in the case of facial wrinkles, polydioxanone(PDO) is embedded to fill the volume, and as it decomposes, it causes a tissue reaction around the area. In obesity, it promotes fat decomposition by improving circulation, and promotes breast enlargement and elasticity through collagen formation. In transdermal hydration, it induces the production of surrounding fibers to increase skin elasticity and moisture. Conclusions : Thread-embedding acupuncture appears to have a cosmetic effect through a mechanism that promotes the production of collagen and elastic fibers in the subepidermal dermal layer and increases the activity of skin moisturizing factors during the absorption process after the PDO suture is embedded.

• Biomolecules & Therapeutics
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• v.31 no.6
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• pp.640-647
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• 2023

The skin, the largest organ in the body, undergoes age-related changes influenced by both intrinsic and extrinsic factors. The primary external factor is photoaging which causes hyperpigmentation, uneven skin surface, deep wrinkles, and markedly enlarged capillaries. In the human dermis, it decreases fibroblast function, resulting in a lack of collagen structure and also decreases keratinocyte function, which compromises the strength of the protective barrier. In this study, we found that treatment with γ-aminobutyric acid (GABA) had no toxicity to skin fibroblasts and GABA enhanced their migration ability, which can accelerate skin wound healing. UVB radiation was found to significantly induce the production of matrix metalloproteinase 1 (MMP-1), but treatment with GABA resulted in the inhibition of MMP-1 production. We also investigated the enhancement of filaggrin and aquaporin 3 in keratinocytes after treatment with GABA, showing that GABA can effectively improve skin moisturization. In vivo experiments showed that oral administration of GABA significantly improved skin wrinkles and epidermal thickness. After the intake of GABA, there was a significant decrease observed in the increase of skin thickness measured by calipers and erythema. Additionally, the decrease in skin moisture and elasticity in hairless mice exposed to UVB radiation was also significantly restored. Overall, this study demonstrates the potential of GABA as functional food material for improving skin aging and moisturizing.

• The Journal of the Convergence on Culture Technology
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• v.4 no.3
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• pp.197-207
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• 2018

The radish skin and radish greens (mucheong) are an edible part of the radish. But they are removed before eating the radish and used as a byproduct or an animal feed material because of their tough and rough texture. This study was conducted to investigate the effect of supercritical heat-treated radish-extract on UV-induced Hos: HRM-2 wrinkled mouse animal model on anti-aging wrinkles. Supercritical heat-treated radish-extract was applied on the back of seven-weeks old HRM-2 mice. The effect of HRE on skin thickness, elasticity and wrinkle formation of the mice was observed by using UVB lamp to induce melanogenesis and wrinkle formation. As the result, increased depth of wrinkles was observed in the negative control group in comparison to the normal group. In contrast, decreased depth of wrinkles was observed in the radish-extract-free group compared to the negative control group. In the study of the effect of radish-extract on wrinkle-formation related gene expression and protein what protein expression, MMP-2 and MMP-2 gene expression significantly increased in the negative control group compared to the normal group. The gene expression reduced independence to the mass of radish-extract treated. Similar to quantitative results of mRNA expression, the expression of MMP-2 protein increased as a result of UVB-irradiation. The MMP-2 expression was inhibited in dependence to the mass of radish-extract treated. In conclusion, the supercritical heat-treated radish-extract has an effect on improving skin wrinkles not only when it is applied to the skin but also when orally ingested. Thus, it can be effectively used as a composition to health functional products. Thereafter, we can also conclude that radish, a food that does not show any side-effects even upon long-term intake, can reduce wrinkle formation as well as improve skin elasticity when taken regularly for a long period.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.174-177
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• 2008

This paper replaces an conventional 300-austenitic stainless steel sheet to a 400-ferritic stainless steel for the cost reduction of a pulsator cover of a washing machine. However, ferritic stainless steel has poor formability in comparison with austenitic one. The low formability of ferritic steel results in problems during stamping such as fracture, wrinkling, shape inaccuracy and so on. Design modification of the stamping tool is carried out with the aid of the finite element analysis for multi-stage stamping process. The simulation results show that fracture occurs on top of the product while wrinkles are generated by the excess metal near the wing part. Modification of the initial stamping die is performed to improve metal flow and to eliminate problems during the stamping process. Simulation with the modified design fully demonstrates that safe forming is possible without inferiorities.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.286-287
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• 2008

The determination of roll speeds in continuous rolling system is an important factor along with the design of roll profile and roll gap. The tensile force on the workpiece induces reduced cross section area and the compressive force induces wrinkles. To determine the optimal roll speeds of current rough rolling system for wire rod, FE analysis was performed. We could predict the workpiece shape and the stress level more precisely by considering the elasto-plastic behavior of workpiece. Also the efficient analysis methodology is presented to reduce the calculation time by combining the ALE and lagrangian method.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.118-121
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• 2008

Flexible die is more efficacious than fixed die which is generally used in stretch forming process in view of production cost. Accordingly, in order to verily the validity of the flexible forming process, curved thin skin structure forming analyses using the fixed and flexible die were performed. As results, merit and demerit with regard to the fixed and flexible die were confirmed. The result of the stretch forming process analysis using the flexible die was better than that using the fixed die in view of the elastic recovery. However wrinkles were occurred on the sheet material due to die cavities between the punches in the flexible forming process, thus the solutions against these problems were presented.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.230-233
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• 2008

Stainless steels are alloy steels with iron as the primary constituent and chromium, nickel, and manganese as principal alloying elements. In addition to automotive, construction, and transportation industries, stainless steels have a variety of applications in the food, chemical, and pharmaceutical industries. Some common products made from stainless steel are sinks, wash basins, kitchen vessels, and cutlery. Among ferritic stainless steels, type 409 can be cold-formed easily and are used for deep-drawn parts such as vessels for the chemical and food industries. In this study, forming analyses and experiments to prevent the occurrence of inferiority such as wrinkles, crack, and neck for automotive muffler part are carried out to save the optimal conditions during forming by modifying the blank size and shape, blank holding force etc.