• Journal of Korean Society for Quality Management
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• v.49 no.3
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• pp.233-243
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• 2021

Purpose: The study focused on localization of the enhanced applique armor kit (EAAK), which are applied to Korea Assault Amphibious Vehicle (KAAV). Methods: For this propose, we developed the manufacturing technology by analyzing the original products. Considering the conditions used in the military, we made the test evaluation criteria. Results: In results, The EAAK developed through this research performs equivalent performance compared to Rafael, Co. Thus, It is possible not only stably supply a parts of EAAK for maintenance, but also to reduce costs due to import substitution effect. Conclusion: It is expected that the manufacturing technology and test evaluation criteria accumulated through this study can be used in the localization of similar parts.

• Journal of Fashion Business
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• v.26 no.3
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• pp.98-115
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• 2022

The purpose of study was to analyze the process of accepting by BTS fans. The methodology used in this study was qualitative research using grounded theory and the results of the study follow. As a result of open coding, 47 concepts, 23 subcategories, and 14 categories were derived. In the axis coding stage, the casual conditions were "Recognition of BTS image," "Fascinated by BTS image," "Simple consumption of BTS image," and "Arising and expansion of curiosity about BTS image." The contextual conditions were "Accessibility of BTS image" and "Abundance of BTS image searching paths." The central phenomenon appeared to be "Immersing and studying BTS image." The arbitration conditions were "Capabilities required to reproduce BTS image" and "Motivation for contributing BTS image." The actions/interactions were "Presenting BTS image," "Contribution to the spread of BTS image," and "Involved in forming new BTS image." The result was "Emergence and expansion of new BTS image meaning" and "Strengthening attachment to BTS." Through process analysis, it was found that acceptance of BTS images consisted of five stages: "Recognition of BTS image," "Becoming curious about BTS image," "Searching BTS image," "Intervention of BTS image." and "Reproduction of BTS image." As a result of deriving the core categories through selective coding, the core category was "Forming a bond while participating in the BTS image."

• Composites Research
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• v.22 no.6
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• pp.52-62
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• 2009

This paper is for the state of the art of the lightweight protective clothing against the mine, and it covers the preliminary work focused on the appropriate protection, ballistics, convenience, and wearability. It is suggested that the lightweight protective clothing should be fabricated with the laminated materials of high strength woven and non-woven fabrics to reduce the weight and thickness, thus improving the wearability. And partial reinforcement of the protective clothing is necessary to prevent the mortal wound near the important parts of the body without disturbing the arbitrary activity. The composition of the protective clothing should be designed in consideration of easy putting-on and taking-off in addition to easy divesture, which require little motion of the body is in case of serious injury. Additionally, status of the practical technique for high performance and ultra-light hybrid armor material were also described.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.3
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• pp.576-585
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• 2002

A three-dimensional Lagrangian explicit time-integration finite element code for analyzing the dynamic impact phenomena was developed. It uses four node tetrahedral elements. In order to consider the effects of strain rate hardening, strain hardening and thermal softening, which are frequently observed in high-velocity deformation phenomena, Johnson-Cook model is used as constitutive model. For more accurate and robust contact force computation, the defense node contact algorithm was adopted and implemented. In order to evaluate the performance of the newly developed three-dimensional hydrocode NET3D, numerical simulations of the oblique impact of mild steel plate by mild steel sphere were carried out. Ballistic limit about various oblique angle between 0 degree and 80 degree was estimated through a series of simulations with different initial velocities of sphere. Element eroding by equivalent plastic strain was applied to mild steel spheres and targets. Ballistic limits and fracture characteristics obtained from simulation were compared with experimental results conducted by Finnegan et al. From numerical studies, the following conclusions were reached. (1) Simulations could successfully reproduce the key features observed in experiment such as tensile failure termed "disking"at normal impacts and outwards bending of partially formed plus segments termed "hinge-mode"at oblique impacts. (2) Simulation results fur 60 degrees oblique impact at 0.70 km/s and 0.91 km/s were compared with experimental results and Eulerian hydrocode CTH simulation results. The Lagrangian code NET3D is superior to Eulerian code CTH in the computational accuracy. Agreement with the experimentally obtained final deformed cross-sections of the projectile is excellent. (3) Agreement with the experimental ballistic limit data, particularly at the high-obliquity impacts, is reasonably good. (4) The simulation result is not very sensitive to eroding condition but slightly influenced by friction coefficient.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.74-74
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• 2012

섬유 프리프레그(Prepreg)는 강화섬유를 수지에 함침하여 B-stage로 만든 복합재료의 중간성형재료이다. 최종적으로 프리프레그를 금형에 적층하여 가열 가압하여 수지를 경화함으로써 최종제품이 완성된다. 본 연구에서는 직물형 프리프레그를 사용하였는데, 사용되는 직물형태로는 복합재료 성형공정에서 형태안정성이 우수한 평직물과 능직물이 주로 사용된다. 직물형 프리프레그를 사용한 복합재료는 작업성과 형태안정성이 우수하면서 내충격특성이 우수하여 오토바이용 헬멧, 방탄용 헬멧 등에 주로 사용된다. 프리프레그에 요구되는 주요 특성중 하나는 Tack성으로서, 성형 과정에서 프리프레그를 여러 장 적층할 때 적층된 층 간에 미끄러지지 않으면서 잘 고정되어 적층 작업을 원활하게 하는 역할을 한다. Tack성은 수지의 B-stage 경화 후의 점성 거동에 따라 변화될 수 있는 것으로 표면의 끈끈함의 정도로서 알 수 있다. Tack성은 온도에 민감하여 측정 시에 일정한 온도의 유지가 중요하다. 이러한 온도에 대한 민감성 때문에 프리프레그의 저장시 저온에서 저장하는 것이 원칙인데, 상온에 있을 경우 시간경과에 따른 Tack성 변화가 크게 나타나게 된다. 따라서 본 연구에서는 아라미드 섬유와 열경화성수지를 이용하여 프리프레그를 제조하고 이를 상온상태에서 보관 시 일정시간 경과에 따른 Tack성 변화를 알아보고자 하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.597-602
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• 2017

A method is proposed to secure the reliability of the antibacterial test method for textile materials used in the military. Antibacterial activity refers to the inhibition of bacterial growth and removal of harmful bacteria. Through KS K 0693 'Antibacterial Test Method for Textile Material', it is considered that there is a high possibility of error due to the human eye measurement. Therefore, the measurement reliability is improved by applying the image processing. As a result of the measurement, the proposed method showed a difference of about 0.9% compared with the results by conventional test method. The proposed method has the merits that the reliability can be secured by eliminating the error of the measurer, and the measurement time can be reduced.

• The Korea Journal of Herbology
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• v.26 no.1
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• pp.75-80
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• 2011

Objectives : The aim of the present study is to investigate the hypotensive effect of Samhwangsasim-tang (SHSST), Samigangap-tang (SMGAT) and Bangtan-tang (BTT) in stroke-prone spontaneously hypertensive rats (SHR-SP). Methods : SHR-SP rats were treated with SHSST, SMGAT and BTT at dose of 200 mg/kg/day orally for 5 weeks, respectively. Results : Treatment SHR-SP rats with SMGAT significantly lowered blood pressure but not in the SHSST or BTT treat groups. On the other hand, SHSST, SMGAT and BTT ameliorated endothelium-dependent and independent vascular relaxation in the phenylephrine-precontracted aorta and carotid artery, respectively. Conclusions : These results indicated that SMGAT has an antihypertensive effect and SHSST, SMGAT and BTT improve vascular function in stroke-prone hypertensive rat model, respectively.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.6
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• pp.1121-1126
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• 2010

Borosilicate glass (81% $SiO_2$-2% $Al_2O_3$-13% $B_2O_3$-4% $Na_2O_3$) was prepared, and the glass was ion exchanged in $KNO_3$ powder containing different temperature and time. The $K^+-Na^+$ ion exchange takes place at the glass surface and creates compressed stress, which raise the mechanical strength of the glass. The depth profile of $Na^+$ and $K^+$ was observed by electron probe micro analyzer. With the increasing heat-treatment time from 0min to 20min, the depth profile was increased from 17.1um to 29.4um, but mechanical properties were decreased. It was also found out that excessive heat treatment brings stress relaxation. The Vickers hardness, Fracture Toughness and bending strength of ion exchanged samples at $570^{\circ}C$ for 10min were $821.8H_v$, $1.3404MPa{\cdot}m^{1/2}$, and 953MPa, which is about 120%, 180%, and 450% higher than parent borosilicate glass, respectively. Transmittance was analyzed by UV-VIS-NIR spectrophotometer. Transmittance of ion exchanged borosilicate glass was decreased slightly at visible-range. It can be expected that transparent bulletproof materials in more light-weight and thinner by ion exchanged borosilicate glass.

• Composites Research
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• v.23 no.6
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• pp.14-18
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• 2010

Among the factors that threaten spacecraft, Micrometeoroid and Orbital Space Debris(MMOD) cause damage to spacecraft and impact velocity is about 8~70km/s. Nowadays, various Whipple Shield are studied and applied to protect spacecraft. As the materials used to Shielding System, aluminum is usually used but composite is also used increasingly. So this study compared characteristics of hypervelocity impact of Aluminum and composites through finite element analysis. The Projectile was a spherical shape using Aluminum 2017-T4, and aluminum plate was using Aluminum 6061-T6, CFRP plate was using T300/5208. Initial impact velocity of projectile was 1km/s. As a result, kinematic energy of projectile decreased to about 64J and about 63J for aluminum plate and CFRP plate, respectively after impact. Although both results is almost same about the absorption of impact energy, you can think the CFRP has good ballistic characteristic, because CFRP is lighter about 1.7 times compared with density of aluminum.

• Journal of Fashion Business
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• v.24 no.1
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• pp.88-101
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• 2020

The music videos of BTS go beyond the limit of media promoting music and shows their meaning in various ways and complete the visual message of music through fashion style. BTS' fashion style in the music videos shows a change in symbolic representation of the genre of each album and song, of which gender images are changing aligned with the music messages of BTS. The purpose of this study was to derive gender images of fashion style in BTS music videos and to interpret their meaning based on Judith Butler's theory that performativity creates discourse through iterative process. It is conducted as a research method, an analytical study was conducted in parallel with literature studies and empirical case analysis. The scope of the study was limited to 301 costumes that appeared in 21 official music videos from debut single album '2Cool 4 Skool' released in 2013 to the mini album 'Map of the Soul: Persona' released in 2019. As a result of the analysis, the controversial fashion style, challenging fashion style, boyish fashion style, hybrid fashion style, the playful fashion style were revealed. The conclusion of studying the gender image of BTS, interpreted by this analysis using Judith Butler's theory, is as follows. The gender image of BTS is the traditional image that identifies with the dominant gender discourse, the resistive gender image that intentionally distances mainstream culture, the eclectic image parodying the gender of the opposing term, and the deconstructive image that transcends the dominant gender discourse.