• Journal of the Korea Fashion and Costume Design Association
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• v.23 no.4
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• pp.133-148
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• 2021

Due to the COVID-19 pandemic, many people started working from home while avoiding unnecessary going-outs. As the 'stay-at-home life' becomes standard daily life, the pajamas market is absorbing young consumers, especially targeting Generation MZ, by using one-mile fashion that breaks down the boundary with everyday clothes. Also, owing to the demand for environmentally-friendly textiles, based on the strengthened environmental regulations, the development of textiles considering the environment is expanding. Thus, the purpose of this study is to develop fashion pajamas using environmentally-friendly textiles targeting Generation MZ. After theoretically considering the current status of recycled PETs and the pajama market by referring to preceding research, relevant books, and Internet data, this study performed the process setting up the design concepts, developing textiles, developing textile designs, and developing pajamas designs. As a result, this study wove two kinds of mixed textiles using recycled PETs and silk with the concept of 'Going out pajamas', and designed a total four patterns to be applied to those textiles, then digitally printed them. Using the developed textiles, this study produced a total four kinds of pajamas that were practical, trendy, and also good to be used as clothes for going-out. The consumers who are exhausted from the limited environment of the COVID-19 pandemic, are requesting comfortable and trendy in & out door fashion. For this reason, the results of this study are significant in the aspect of suggesting the new-normal fashion trend for pajamas designs.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.4
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• pp.85-94
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• 2004

Waste wood-plastic composite panels are made on different hot press molding conditions, and tested for apparent density, water absorption, expansion in thickness and flexural strength. From the test results, regardless of molding temperature and molding time, the apparent density of the composite panels is increased with an increase in the molding pressure, while their water absorption is decreased with an increase in the molding pressure. The flexural strength of the composite panels is markedly increased with increasing molding pressure, molding temperature and molding time, and tends to become nearly constant at a molding temperature of $120^{\circ}C$ and a molding time of 15min.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.9
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• pp.25-32
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• 2006

In this study, the characteristics of filament wound composite/aluminum ring specimens were investigated at cryogenic temperature. The ring specimens were manufactured using carbon fibre and Type B epoxy resin which had been developed for cryogenic use. As a result of measuring thermal strains at -150℃, it was found that compressive thermal stress was induced in composite part on the contrary, tensile thermal stress in aluminum part which was about 32% of yield stress and in turn, caused aluminum to be yielded at lower load level. In addition, Thermal strains which resulted from finite element analysis showed good agreement with those of the experiment. After 6 mechanical loading cycles had been applied to the ring specimen at -150℃, tensile tests were performed at -150℃ using a split disk fixture. As a result, it was shown that composite strength in a liner-composite tank structure which is for the use of cryogenic propellant tank would be decreased by auto-frettage pressure which is applied to it.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.491-498
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• 2013

The purpose of this study was to evaluate the economy and efficiency of two trained athlete groups of different training status. The subjects were 20 elite athletes composed of the cyclists group (n=10) and triathlon group (n=10). All subjects performed steady state testing at 50, 100, and 150 watts, with ample time to reach resting $VO_2$ and ventilation values between stages. The efficiency of two groups appears to be quite different, with triathlon competitors displaying superior efficiency values for the transitions from 0 to 50 and 100 watts. This same principle likely explains the economy of the groups, as triathlon competitor was again more economic at 50 and 100 watts. As though this matching of oxygen consumption and workload they can reduce the amount of oxygen deficit that must be repaid post exercise.

• Journal of the Korean Electrochemical Society
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• v.20 no.1
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• pp.13-17
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• 2017

In this study, we studied the organic electrolyte application to electrochemical capacitor for high operation voltage. For high operating voltage, 5 wt % of gamma butyroloctone (GBL) was added in the bare electrolyte. During the cycle performance, stable SEI layers were formed by reductive decomposition of additive GBL. As a result, columbic efficient of 1M $SBPBF_4$ in EC:DMC(1:1) with GBL composite was enhanced to 70% after the 2000th cycle at voltage range 0-3.5 V. Additionally, SEI layer protected the surface of electrode and prevent the side-reaction between electrolyte to electrode.

• Transactions of the Korean hydrogen and new energy society
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• v.24 no.6
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• pp.510-517
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• 2013

The ammonia-water based power generation cycle utilizing liquefied natural gas (LNG) as its heat sink has attracted much attention, since the ammonia-water cycle has many thermodynamic advantages in conversion of low-grade heat source in the form of sensible energy and LNG has a great cold energy. In this paper, we carry out thermodynamic performance analysis of a combined power generation cycle which is consisted of an ammonia-water regenerative Rankine cycle and LNG power generation cycle. LNG is able to condense the ammonia-water mixture at a very low condensing temperature in a heat exchanger, which leads to an increased power output. Based on the thermodynamic models, the effects of the key parameters such as source temperature, ammonia concentration and turbine inlet pressure on the characteristics of system are throughly investigated. The results show that the thermodynamic performance of the ammonia-water power generation cycle can be improved by the LNG cold energy and there exist an optimum ammonia concentration to reach the maximum system net work production.

• Composites Research
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• v.16 no.1
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• pp.13-18
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• 2003

Prediction of composite fatigue life is not a straightforward matter, depending on various failure modes and their interactions. In this paper, a methodology is presented to predict fatigue life and residual strength of composite materials based on Phenomenological Model(non-linear fatigue damage model). It is assumed that the residual strength is a monotonically decreasing function of the number of loading cycles and applied fatigue stress ratio and the model parameters(strength degradation parameter and fatigue shape parameter) are assumed as function of fatigue life. Then S-N curve is used to extract model parameters that are required to characterize the stress levels comprising a randomly-ordered load spectrum. Different stress ratios (${\sigma}_{min}/{\;}{\sigma}_{max}$) are handled with Goodman correction approach(fatigue envelope) and the residual strength after an arbitrary load cycles is represented by two parameter weibull functions.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.11a
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• pp.21-21
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• 2011

개인적 삶의 질 향상과 함께 사회적인 삶의 가치를 추구하여 인체친화적이며 동시에 환경 친화적인 제품 소비에 가치를 두는 LOHAS 트렌드의 영향으로 의류 제품에서는 소비자의 요구 수준에 맞춘 고급화, 고기능화된 의류 상품 및 소재 중심의 소비와 함께 친환경 소재, 리사이클 소재 등에 대한 관심이 증가하고 있다. 최근 Ramie 복합 소재는 이러한 트렌드에 적합한 대표적인 소재로서 고감성/웰빙 신섬유 제품 개발을 통해 신시장 개척이 가능한 아이템으로 주목받고 있다. 한편, Ramie는 땀에 대한 흡습성과 속건성이 우수하고 청량감이 있어 주로 여름 소재로 활용되어 왔으나 촉감이 좋지 못하고 광택성이 떨어지는 단점이 있어 이를 보완하기 위해 촉감이 좋고 광택성이 뛰어난 레이온 계열의 소재와 혼방하여 고급스럽고 환경 친화적인 의류소재로써 개발이 진행되고 있다. 본 연구에서는 이러한 레이온계 섬유 중에서 상품성이 modal 섬유 Tencel 섬유를 각각 혼방한 Ramie/Modal(28's,30's), Ramie/Tencel(28's) 복합소재의 반응성 염료에 대한 염색특성을 비교 고찰해 보았다. 실험은 Heterobifunctional type 반응성 염료 3종(Red, Yellow, Blue)을 이용하여 흡진 거동, 빌드업 특성, 겉보기 색상농도 등을 비교하였으며 1/1 standard 농도에서의 제반 견뢰도를 비교 평가하였다.

• Resources Recycling
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• v.19 no.4
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• pp.51-57
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• 2010

As a recycling of Si sludge from Si wafer process, a Si-SiC-CuO-C composite material was synthesized and investigated as an anode material for lithium batteries. The Si sludge consisted of Si, SiC, machine oil, and metallic impurities. The oil and metal impurities was removed by organic washing, magnetic separation, and acid washing. The Si-SiC-CuO-C composite from the recovered Si-SiC mixture was prepared by high-energy mechanical milling. According to the electrochemical tests such as charge-discharge capacity and cycling behavior, it showed the improved cycle performance. The SiC and CuO-related phases were presumed to restrain the volume expansion of the anode and Fe, however, should be removed below 10 ppm prior to synthesis of the composite because it caused the capacity loss of the active material itself.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.77-77
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• 2009

ELV(; End of Life Vehicles)를 비롯한 최근 환경 동향은 자동차 전장 모듈에 대하여 다양한 무연 솔더 적용을 요구하고 있다. 특히 자동차 엔진룸과 트랜스미션은 가동 중 고온 및 진동의 지속적인 영향을 받기 때문에 이와 유사한 환경에서의 신뢰성 연구가 필요한 시점이다. 이에 본 연구에서는 Sn3.5Ag, Sn0.7Cu, Sn5.0Sb 솔더 조성에 대하여 복합환경 조건하에서 접합부 신뢰성을 평가하였다. 복합환경을 구현하기 위하여 $-40{\sim}150^{\circ}C$ 범위의 온도 사이클과 랜덤 진동을 동시에 인가하였으며, 진동 가속도 3G, 진동주파수는 10~1000Hz 로 설정하여 자동차 환경을 충족하였다. 복합시험의 1 cycle 은 20 시간이며, 총 120 시간의 시험 동안 진동의 영향 및 진동과 고온이 동시에 작용하였을 경우의 영향에 대해 비교하였다. 테스트 모듈 제작을 위해 450 um 의 솔더볼이 적용되었으며, 각 조성의 솔더볼을 이용하여 BGA test chip 제작하였고, 제작된 BGA test chip 은 다시 daisy chain PCB 위에 실장 및 리플로우 공정을 통해 접합되었다. 테스트 동안 In-situ 로 저항의 변화를 관찰하여 파단의 유무를 판단하였고 전자주사현미경을 통해 파괴 기전을 평가하였다. 복합시험 시간에 따른 전단강도를 측정하였으며, 각 조성에 대하여 상이한 전단강도 변화를 관찰하였다. 계면 IMC 형상은 전단강도 변화에 영향을 주었으며, 특히 높은 온도가 IMC 성장을 촉진시켜 전단강도 감소에 영향을 주었다. 본 복합환경 시험 조건에서는 Sn0.7Cu 가 가장 안정적이었으며, 파단면을 관찰한 결과 연성파괴 모드가 관찰되었다.