• Tribology and Lubricants
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• v.32 no.3
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• pp.75-81
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• 2016

Future electronics such as electronic paper and foldable cellphone are required to be flexible and transparent and should have a high performance. In order to fabricate the flexible electronics using flexibility transfer process, techniques for transferring various devices from rigid substrate onto flexible substrate by elastomeric stamp, have been developed. Adhesion between the elastomeric stamp and various devices is crucial for successful transfer process. The adhesion can be controlled by the thickness of the stamp, separation velocity, contact load, and stamp surface treatment. In this study, we fabricated the bump shape stamp consisting of a UV-curable polymer and investigated the effects of curing condition, separation velocity, and contact load on the adhesion characteristics of bumps. The bumps with hemispherical shape were fabricated using a dispensing process, which is one of the ink-jet printing techniques. Curing conditions of the bumps were controlled by the amount of UV irradiation energy. The adhesion characteristics of bumps are evaluated by adhesion test. The results show that the pull-off forces of bumps were increased and decreased as UV irradiation energy increased. For UV irradiation energies of 300 and 500 mJ/cm², the pull-off forces were increased as the separation velocity increased. The pull-off forces also increased with the increase of contact load. In the case of UV irradiation energy above 600 mJ/cm², however, the pull-off forces were not changed. Therefore, we believe that the bump shape stamp can be applied to roll-based transfer process and selective transfer process as an elastomeric stamp.

• Science of Emotion and Sensibility
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• v.25 no.4
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• pp.3-20
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• 2022

The origins of the world-recognized Korean gat can be traced back to Gojoseon, and the jades for the sangtu and gwanja come from Hongshan culture. This study examines the etymology of the hat, the symbolism of the gat and the jade comb, and the history of the development of the accessories for the hat. The research methods of literature review, investigation of relics and murals, and analysis of cases of pronunciation changes were used. Most of the relics excavated from the Hongshan are identical to those excavated from Korea. The Byun-Khan people wore a triangle-shaped conical hat (the byun), which was shaped to fit the protruding sangtu hairstyle, with a foldable brim that, if pulled downward, changed the hat to a gat. The Chu sangtu, a pointed top-knot hairstyle, is uniquely found among Northeast Asian peoples, and it is an ethnic symbol for Koreans. Until the modern period, many Koreans wore their hair in the sangtu style, indicating their descent from the sky. Jade combs shaped like birds and clouds from the Hongshan period emphasized the religious nature and ceremony of hair styling at that period. The word hat is widely used to refer to gat all over the world. The pronunciation of ㄱg, ㅎh. and ㅋq/kh are closely related to each other, and the ancient pronunciation ㄱg gradually evolved to ㅎh or ㅋq/kh. The English 'Hat' and Korean 'Gat' were transformed from the middle-ancient sound 'gasa > gosa > got' of the crown 'gwan, gokkal'. This creative hair style culture that started from the Hongshan culture continued to be fashionable during the Gojoseon Dangun period, and the decoration techniques for hats and accessories were inherited over time and continuously developed. Along with the method of making gat, creative hair-related parts, such as manggeons, donggot pins, gwanja buttons, and fine combs were developed over the course of a thousand years.

• Korea Science and Art Forum
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• v.37 no.2
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• pp.219-230
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• 2019

According to the National Statistical Office, the number of senior citizens aged 65 or over has exceeded 7 million as of 2017, and the number of senior citizens who live alone among them exceeded 1.3 million. Most of the senior citizens who live alone suffer from absolute poverty (68.5% of them has monthly income less than 500,000 won) and they have difficulties for basic living in the blind spot of our society. In particular, the heating is quite a serious issue for the senior citizens who live alone and belong to vulnerable social group in the winter, and to make it worse, they are exposed to frequent fire accidents due to the negligence in handling electric appliances such as electric heaters and electric pads. The main reason the indoor tent products are being used by senior citizens who live alone is that it saves energy, ensures warm sleep, and improves fire safety. Following the expansion of the indoor tent market, this study focused on the idea that there is a need for an in door tent suitable for senior citizens who live alone and belong to low income bracket and intended to improve its efficiency in relation to use, resting, and storage. For this, a basic survey was conducted on the products of existing brands to analyze advantages and disadvantages and it was possible to understand the demands that consumers have for existing products. Accordingly, a survey on consumer preference was conducted using a designed model and the Zabara typp, which demonstrated the best efficiency in terms of installation convenience, space usability, and appearance design was selected. Based on the results of selection, the product design and final prototype were completed. The results and details of the study are as follows; First, factors that were not recognized in product development phase could be identified through usability survey and interview with actual users. Second, for the effective aspect of the prototype, senior citizens could install and fold the tend more easily and quickly than expected. Based on these results of this study, it is expected that not only senior citizens who live alone but also various other users can use the tent to create another comfortable private space indoors.