• 한국광학회지
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• 제18권4호
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• pp.264-269
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• 2007

기존 필라멘트 방식의 루미나리에용 조명의 단점을 극복하기 위해 필라멘트를 LED로 바꾸기 위한 연구가 활발하게 진행 중이다. 본 연구는 루미나리에용에 적합한 LED패키지 구조를 만들기 위해 ray tracing simulator를 이용해 다양한 구조를 모델링하고 시뮬레이션을 통해 각 구조에서의 배광분포를 측정하였다. 시뮬레이션 결과, LED 패키지의 내부 반사경의 각을 증가시킬수록 배광분포가 두 개의 피크로 갈라지면서 피크간의 각이 점점 커졌다. 또한 외부 반사경 각이 증가함에 따라 양쪽 피크간의 각이 점점 줄어들다가 $50^{\circ}$를 기준으로 다시 증가하였다. 이러한 결과는 LED에서 발생한 빛이 두 개의 반사경에 의하여 반사되는 각도가 달라짐에 의하여 발생함을 알 수 있었다. Ray tracing simulator를 이용하여 구한 LED 패키지 구조의 조건을 적용하여 루미나리에용 LED패키지를 제작하였고 배광분포 측정기를 이용해 광 특성을 측정하였으며 시뮬레이션의 결과와 유사한 특성을 얻었다.

• International Journal of Industrial Entomology and Biomaterials
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• 제20권2호
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• pp.61-67
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• 2010

The bivoltine tropical tasar ecoraces of Antheraea mylitta Drury produces cocoons for seed production under seed crop rearing (July-August with $22{\sim}30^{\circ}C$ temperature and 50~70% relative humidity) and for silk production under commercial crop rearing (September-December with $17{\sim}27^{\circ}C$ temperature and 60~80% relative humidity). To consider the impact of hybrid vigour on egg, larva, cocoon and silk related commercial traits, the $F_1$ hybrids made among Daba, Jata and Raily ecoraces were assessed successively for three years. The hybrid vigour in the $F_1$ hybrid of Daba$\times$Jata ($T_7$) was positive for egg fertility (+23.1%), shell weight (+25.6%), silk yield (+79.0%) and filament length (+68.1%), with filament of high denier (11.98d) and reduced larval span (-7.1%). The Jata$\times$Daba ($T_8$) hybrid has shown negative heterosis in egg fertility (-8.0%) compared to the other F1 hybrids, Daba$\times$Raily ($T_9$) and Raily$\times$Daba ($T_{10}$), when they rise simultaneously during the commercial crop season. The better performance of parental ecoraces ($T_4$ to $T_6$) in their commercial traits during commercial crop over parents of seed crop ($T_1$ to $T_3$) and the superior performance of $F_1$ hybrids ($T_7$ to $T_{10}$) over parents of commercial crop ($T_4$ to $T_6$) during commercial crop season indicates the apparent hybrid vigour in tasar $F_1$ hybrids. As the Daba$\times$Jata ($T_7$) and Jata$\times$Daba ($T_8$) $F_1$ hybrids have shown highest hybrid vigour, their rearing during commercial crop can optimize the silk productivity and commercial sustenance of the tasar silk industry.

• 한국의류산업학회지
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• 제14권4호
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• pp.641-647
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• 2012

This study investigates the sound properties of fabric frictional sound (SPL, ${\Delta}L$, ${\Delta}f$) according to the film type of PTFE laminated vapor-permeable water-repellent fabrics in order to understand the relationship between SPL and the basic properties of fabrics such as layer, yarn type, and thickness of fiber. This study accesses their mechanical properties and determines how to control them to minimize SPL. Eight PTFE laminated water-repellent fabrics, composed of four different film types (A, B, C, D) and with two different fabrics, were used as test specimens. Frictional sounds generated at 1.21m/s were recorded by using a fabric sound generator and SPLs were analyzed through Fast Fourier Transformation (FFT). The mechanical properties of fabrics were measured by KES-FB. The SPL value was lowest at 74.4dB in film type A and highest as 85.5dB in type D. Based on ANOVA and post-hoc test, specimens were classified into less Loud Group (A, B) and Loud Group (C, D). It was shown that SPL was lower when 2 layer (instead of 3 layer), filament yarn than staple, and thin fiber than thick were used. In Group I, shearing properties (G, 2HG5), geometrical roughness (SMD), compressional properties (LC, RC) and weight (W) showed high correlation with SPL however, elongation (EM) and shear stiffness (G) did with SPL in Group II.

• 한국의류산업학회지
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• 제15권6호
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• pp.985-992
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• 2013

Polytrimethylene terephthalate(PTT) offers several advantageous properties such as good tensile strength, uniformity, stiffness, toughness, UV stability, resilience, stain resistance, outstanding elastic recovery, and dyeability. The effects of annealing temperature on physical properties and the structure of PTT filaments and yarn were investigated by measuring wide-angle X-ray diffraction (WAXD), density, optical birefringence, dynamic visco elasticity, and tensile testing. The intensity of maximum tan ${\delta}$ decreased and the temperature of maximum tan ${\delta}$ shifted to a higher temperature as the annealing temperature of filaments increased; however, it shifted to a lower temperature when the annealing temperature exceeded $130^{\circ}C$. In addition, crystallinity, density and D-spacing of (010) crystal face increased as the annealing temperature increased. Optical birefringence and specific stress were almost constant up to $100^{\circ}C$ and then decreased above $130^{\circ}C$. The shrinkage of PTT filament is 0 in boiling water when annealed above $130^{\circ}C$; consequently, the use of annealed fiber above $130^{\circ}C$ can remove thermal instability when dyeing PTT fiber. In the case of yarns, the thermal stability and physical properties of yarns showed the best effect when the ply number is less than 5, twist number is less than 400tpm, and the annealing time is 20minutes.

• 한국염색가공학회지
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• 제26권1호
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• pp.22-31
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• 2014

This study investigated the physical properties of warm up yarns and their knitted fabrics including the dye affinity and color fastness to washing of these knitted fabrics according to the various dyeing times and temperatures on dyeing process. The results were summarized as follows. The tenacity of Nylon/PP warm-up yarn was 4g/d and breaking strain was 4.5%. The wet and dry thermal shrinkages were higher than those of PET warm-up yarn. The maximum heat flow rate(Qmax) of Nylon/PP warm-up knitted fabric was lower than that of PET warm-up knitted fabric and heat keeping rate(a) of Nylon/PP warm-up knitted fabric was higher as 47% than that of PET warm-up knitted fabric. It was shown that the shape retention and wearing comfort of Nylon/PP warm-up knitted fabric were better than those of PET warm-up knitted fabric. The dye-affinity(K/S) of Nylon/PP warm-up knitted fabric showed maximum value at the dyeing condition of 40minute or 50minute dyeing time with $80^{\circ}C$ dyeing temperature, but PET warm-up knitted fabric showed maximum value at the 30minute or 40minute with $110^{\circ}C$ dyeing temperature. Finally, the color fastness to washing of Nylon/PP warm-up knitted fabric showed good value as between 4 and 5 grade.

• 대한조선학회논문집
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• 제58권5호
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• pp.294-302
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• 2021

In this study, the 3D printing technique called design for additive manufacturing (DfAM) that is widely used in various industries was applied to marine leisure ships of equipment. The DfAM for the stanchion for crew safety was applied to the equipment used in an actual recreational craft. As design constraints, the design alternatives were not to exceed the safety and weight of the existing stainless steel material, which were reviewed, and the production of a low-cost FFF-type 3D printing method that can be used even in small shipyards was considered. Until now, additive manufacturing has been used for manufacturing only prototypes owing to its limitations of high manufacturing cost and low strength; however, in this study, it was applied to the mass production process to replace existing products. Thus, a design was developed with low manufacturing cost, adequate performance maintenance, and increased design freedom, and the optimal design was derived via structural analysis comparisons for each design alternative. In addition, a life-cycle assessment based on the ISO 1404X was conducted to develop sustainable products. Through this study, the effectiveness of additive manufacturing was examined for future applications in the shipbuilding industry.

• 한국융합학회논문지
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• 제12권3호
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• pp.141-149
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• 2021

20세기 후반에 등장한 3D 프린터는 21세기에 들어와 4차 산업혁명의 핵심 분야로 자리매김하고 있다. 메이커 운동의 핵심 장비이자 21세기 새로운 가내수공업의 시발점인 3D 프린터는 여전히 낮은 출력 속도와 한정된 필라멘트 재료로 대량생산의 한계를 드러내고 있지만, 최근 도자 공예가들의 3D 프린터 사용은 기하급수적으로 늘고 있다. 하지만 과거 공예사에서 지난하게 반복되어 온 공예의 경전과 새로운 기술과의 불협화음을 타계하는 방법의 일환으로 본 연구는 3D 프린터를 이용하는 '석고 캐스팅' 기법에 주목했다. 이에 세계 도자 공예분야에서 활발히 석고 기법을 개발해 작가만의 디자인에 적용하고 있는 도예가 토니 한센, 위베 반 간스베크, 제이드 크롬프톤, 류희도의 캐스팅 기법을 분석한 후 효과적인 3D 모델링 방법과 3D 프린터를 이용하는 최적의 슬립 캐스팅 방법의 사례를 제시함으로써 3D 프린터와 공예의 융합을 위한 접점을 찾고자 했다.

• 한국의류산업학회지
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• 제22권6호
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• pp.834-843
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• 2020

This study develops 1/2 dress forms for draping. This study investigated the production status of domestic and foreign products in order to model their shape using CLO 3D. In addition, it developed torso-type and torso-crotch-type products that allowed for draping using a 3D printer. This study analyzed shape and size compared to developed ones after referring to the Size Korea 7th Survey data as well as seven domestic and foreign company websites. The results are follows. First, an investigation of the production status of the products for the size of most of the domestic ones (except K-4) indicated that the waist circumference was slimmer than Size Korea. Bust, waist, and hip circumferences ranged from 42.0 cm, 32.0 cm, and 45.0 cm - 49.0 cm, respectively, in Chinese products; 42.0 cm - 43.0 cm, 30.5 cm - 31.5 cm, and 46.0 cm - 46.5 cm in Japanese products; 43.0 cm, 35.0cm, and 46.5 cm in American products (Japanese body shape applied). Second, an avatar was produced on a 3D software with the average size of 20-24year-old women, and its file modified as a dress form for 3D printing with PLA filament to produce dress forms for draping, workable with pins, using quilting cotton and cotton cloth. Third, the comparisons of the form and flattening between the developed dress forms and the selling ones indicated that flattening was bigger in the waist part of the former than the latter. The waist is produced too slim in the existing dress forms; therefore, it is necessary to correct the waist circumference. Unlike existing dress forms, the developed ones were produced in proximity to the average size of 20-24 year-old women in the Size Korea 7th Survey.

• Advances in nano research
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• 제14권5호
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• pp.435-442
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• 2023

Sports activities, including playing tennis, are popular with many people. As this industry has become more professionalized, investors and those involved in sports are sure to pay attention to any tool that improves athletes' performance Tennis requires perfect coordination between hands, eyes, and the whole body. Consequently, to perform long-term sports, athletes must have enough muscle strength, flexibility, and endurance. Tennis rackets with new frames were manufactured because tennis players' performance depends on their rackets. These rackets are distinguished by their lighter weight. Composite rackets are available in many types, most of which are made from the latest composite materials. During physical exercise with a tennis racket, nanocomposite materials have a significant effect on reducing injuries. Materials as strong as graphite and thermoplastic can be used to produce these composites that include both fiber and filament. Polyamide is a thermoplastic typically used in composites as a matrix. In today's manufacturing process, materials are made more flexible, structurally more vital, and lighter. This paper discusses the production, testing, and structural analysis of a new polyamide/Multi-walled carbon nanotube nanocomposite. This polyamide can be a suitable substitute for other composite materials in the tennis racket frame. By compression polymerization, polyamide was synthesized. The functionalization of Multi-walled carbon nanotube (MWCNT) was achieved using sulfuric acid and nitric acid, followed by ultrasonic preparation of nanocomposite materials with weight percentages of 5, 10, and 15. Fourier transform infrared (FTIR) and Nuclear magnetic resonance (NMR) confirmed a synthesized nanocomposite structure. Nanocomposites were tested for thermal resistance using the simultaneous thermal analysis (DTA-TG) method. scanning electron microscopy (SEM) analysis was used to determine pores' size, structure, and surface area. An X-ray diffraction analysis (XRD) analysis was used to determine their amorphous nature.

• 감성과학
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• 제18권1호
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• pp.49-58
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• 2015

본 연구는 감성의류용 탄화지르코늄 함유 축열 니트의 원적외선 특성을 연구하였다. 탄화지르코늄 함유 축열 PET 원사가 이성분 방사법에 의해 방사되었다. 이 원사의 core부에는 고점도 PET와 탄화지르코늄을 혼합한 용액을, sheath부에는 저점도 PET 용액을 사용하여 콘쥬게이트 방사를 실시하였다. 이들 방사된 원사의 원소분석과 원적외선 특성 분석이 EDS와 FT-IR 계측기기에 의해 분석되었으며 두 가지 조직의 니트 소재를 편직하여 이들의 열적특성을 분석하였다. EDS 분석에서 Zr 피크를 확인하였으며 원사내에 Zr 원소가 19.29% 함유되어 있음을 확인하였다. 또한 원적외선 분석에서 $5{\sim}20{\mu}m$ 파장 영역에서 원적외선 방사에너지가 $3.65{\times}10^2W/m^2$, 방사율이 0.906 임을 확인하였다. KES-F7 측정기 분석에서 ZrC 함유 편성물의 Qmax 값이 일반 PET 편성물의 값보다 낮은 값을 보였고 보온율 값은 ZrC 함유 편성물이 일반 PET보다 더 높은 값을 보이므로서 ZrC의 축열성을 확인하였다. 열전도도는 Zr의 높은 열전도도 때문에 일반 PET 편물보다 더 높은 값을 보였다. ZrC의 함유가 편물의 촉감에 미치는 영향을 없었으며 편성 조직이 더 큰 영향을 주는 것을 확인하였다.