• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1614-1616
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• 2011

지중송전라인에서 전압등급의 상승은 선로손실을 줄이면서 밀집된 전력수요에 대응하거나 특별히 고전압 수요를 맞추기 위한 것으로 이것은 XLPE Cable의 제조기술이 향상되면서 지속적으로 진행되어온 초고압송전계통의 일반적 추세이다. 이러한 경향으로 해외에서는 케이블 도체의 송전용량을 증대시킬 수 있는 방법으로 케이블 도체에 에나멜 코팅을 하여 집합을 한다. 그러므로써 기존 케이블에서 발생되는 표피현상 및 근접효과에 의한 AC 저항 요소를 줄여 요구하는 전류용량을 기존 비소선절연 케이블에 비해 더 많이 송전할 수 있다. 하지만, 소선절연 케이블이 전류 용량을 증대 시킬 수 있는 장점은 있으나 접속재의 경우 도체의 에나멜 코팅을 제거해야 하는 문제점이 있다. 당사는 에나멜 코팅을 제거하는 방법을 개발 완료함으로써 본 접속재의 개발을 앞당길 수 있었다. 당사는 쿠웨이트 400kV MEW/C/3931 Project에 400kV XLPE 1C${\times}$2500SQ 소선절연 초고압송전라인을 적용하였는데 본고에서는 여기에 적용된 400kV XLPE 1C${\times}$25000SQ 소전절연 케이블 부속재의 신뢰성을 높이기 위한 설계방법, 시험 및 시공에 대하여 요약하였다.

• Journal of the Korean Wood Science and Technology
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• v.46 no.3
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• pp.231-240
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• 2018

Bamboo is one of the major biomass resources that have many advantages such as fast growing, easy cultivation, short rotation, and a relatively lower price. In this study, the anatomical characteristics of Moso bamboo (Phyllostachys pubescens) by age from one-year-old to five-year-old were examined by optical and scanning electron microscopy. Also, the crystalline properties such as relative crystallinity and crystallite width were investigated by an X-ray diffraction method. In one-year-old bamboo xylem, a few vascular bundles showed missing bundle sheath in near the intercellular space. Moreover, one-year-old bamboo had the shortest fiber length and the smallest values in vessel diameter, width of vascular bundle, and thickness of inner layer. One-year-old bamboo also showed the smallest values in the crystallinity and crystallite width. Near epidermis samples had longer fiber length and greater vascular bundle spacing than near pith samples. Relative crystallinity and crystallite width near the epidermis were also higher than near the pith. This study revealed significant differences in qualitative and quantitative anatomical characteristics between one-year-old and two-year- or more old Moso bamboos. It is concluded that the structural differences by bamboo age can be used to differentiate the characteristics of juvenile and mature bamboo.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2000.04a
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• pp.12-13
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• 2000

최근 플라스틱제 식품 포장재에 대한 환경학적 문제가 제기됨으로 인하여 다양한 곡류 단백질의 필름 형성능력에 많은 관심이 모아지고 있다. 단백질 필름으로서 soy protein, wheat gluten, rice bran, corn zein, glatin 및 colloagen 등의 소재들이 많은 관심을 모으고 있으며, 비교적 필름 형성력이 뛰어나고, 저렴한 가격으로 구입할 수 있는 대두 단백질에 커다란 관심이 모아지고 있는 실정이다. 이들 물질로부터 제조된 가식성 필름 및 코팅제들은 식품의 보존기간을 연장시킬 뿐만 아니라 수분 및 용질의 이동을 방지하여 식품의 품질을 개선시킬 수 있다. 또한 이들 필름 및 코팅제들은 산소 및 이산화탄소의 이동, 이로 인한 지방 산화 그리고 휘발성 향기성분들의 감소 등을 조절할 수 있다. 대두 단백질 필름의 사과 코팅제로서의 이용은 개별적 포장이 용이하지 않는 제품들의 코팅제로서 활용하여 대두 단백질 필름 및 코팅제의 잠재적 시장성을 확인하는 하나의 응용분야이다. 본 실험의 목적은 대두 단백질 코팅제를 후지와 golden delicious 사과에 코팅하여 상온 (22$^{\circ}C$)과 냉장온도(2-4$^{\circ}C$)에서 60일동안 보관하여 색도, 경도 및 산도 변화 등을 측정하여 저장 중 사과의 품질에 미치는 영향을 조사하였다. 대두 단백질 코팅제는 대두 단백 용액들 (5g, 8g, 10g/100mL water)에 glycerin (50% w/w의 단백질)을 가소재로 첨가한 후 알칼리 용액으로 pH 9.0에 맞추었다. 그런후 85$^{\circ}C$에서 30분간 가열하여 코팅제를 준비하였다. 후지 사과(붉은색)와 golden delicious 사과 (초록색)를 dipping 방법으로 코팅하여 60일도안 실온과 냉장온도에 저자하여 보존기간의 연장을 확인하였다. 사과품질의 결정인자는 Hunter L, a, b 색도값과 사과의 조직의 강도 (외부 및 내부) 그리고 산도 등을 측정하였다. 코팅된 후지 및 golden delicious 사과의 표피 및 내부 경도는 control과 비교하여 높은 경도를 유지하였다. 또한 냉장온도에서 30일 동안 보관하였을 때, control 사과와 거의 비슷한 경도를 유지하였다. 식품의 색도를 소비자의 기호를 결정하는 중요한 인자이다. 대두 단백질로 코팅된 후지 사과는 상온에서 20일 동안은 control에 비하여 약간의 색도의 증가를 보였으나, 그 후 60일 동안은 색도의 증가를 보이지 않았다. 그러나 냉장 보관한 control 후지 사과에 비하여 색도의 증가가 관찰되었다. 대두 단백질 코팅제가 사과의 색도 변화를 방지하는 효과를 가졌으나, 저장 온도가 색도의 변화에 더욱 큰 영향을 미침을 알 수 있었다. 대두 단백질로 코팅된 golden delicious는 상온에서60일 동안 보관하였을 경우, 사과표피의 색도 변화를 현저히 지연시킴을 확인하였다. 또한 control과 비교하여 성공적으로 사과에 코팅하였으며, 상온에서 보관하여을 때 사과의 품질을 30일 이상 연장하는 효과를 관찰하였다. 이들 결과로부터 대두단백질 필름이 과일 등의 포장제로서 이용할 가능성을 확인하였다.

• Composites Research
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• v.15 no.1
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• pp.1-8
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• 2002

In this study, the flutter analysis for a rectangular box wing and an actual fighter wing with composite shin, aluminum spar and aluminum rib has been conducted. A conservative 3D wing-box model of an actual wing is modeled by MSC/PATRAN and the corresponding free vibration analysis has been performed by MSC/NASTRAN. The finite elements of membrane, rod and shear panel are used. Using the practical ply angles, various composite laminates are composed and analysed. The DLM code which is linear aerodynamic theory in frequency domain is applied to calculate unsteady aerodynamic pressure in subsonic flow region and the V-g and p-k methods are applied to obtain the solution of aeroelastic governing equation in frequency domain.

• Research in Plant Disease
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• v.13 no.1
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• pp.30-33
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• 2007

One hundred and eighty-six leaves of soybean cv. Seokryangputkong that showed mild mosaic symptoms were collected randomly and ELISA tests were conducted with those leaf samples to screen the presence of Cowpea mosaic virus (CPMV). Ninety-three out of 186 samples reacted positively to CPMV, but those samples did negatively to Soybean mosaic virus (SMV). At least, 55 leaf samples revealed higher values than that of positive control. The results strongly confirmed that CPMV occurred severely in soybean cv. Seokryangputkong. However, a question is raised on the primary reservoir and vector for transmission of this virus. Since the farmer changes seeds every year, seed transmission is excluded. The virus was also purified, the analysis of coat protein conformed the virus of cowpea mosaic virus and UV absorption pattern confirmed that the causal virus of mosaic disease in soybean putkong was cowpea mosaic virus.

• Journal of Korean Society of Forest Science
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• v.104 no.3
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• pp.512-518
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• 2015

Pine wilt disease (PWD) caused by pine wood nematode, Bursaphelenchus xylophilus, has become the most serious threat to pine trees in Korea. This study was subjected to investigate effective biological control agent against PWD. To select nematocidal bacteria against PWD, Bacillus licheniformis MH48 was selected among five bacteria due to its high nematocidal potential. B. licheniformis MH48 was tested for cell growth and protease activity to evaluate its nematicidal potential. In the B. licheniformis MH48, cell numbers were highest three days after incubation, while protease activity was highest after seven days. In the effect of different concentrations of B. licheniformis MH48 culture broth against B. xylophilus, 20% concentration of culture broth showed approximately 80% of pine wood nematode mortality compared to the control. Especially, pine wood nematode's cuticle layers were degraded two days after treatment of B. licheniformis MH48 culture broth. The present study suggests that B. licheniformis MH48 can be one of the potential biocontrol candidates against pine wood nematode due to its ability to produce protease.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.45 no.3
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• pp.225-235
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• 2019

Cymbopogon citratus (CC) and Perilla frutescens (PF) are known to exert various biological effects. However, their skin hydration and skin barrier effects remain unclear. This study investigated effects of their extracts on skin hydration and skin barrier and analysed the phenolic compounds. effects of these extracts on skin hydration in HaCaT cells showed that Hyaluronic acid production in cells treated with ethanol extracts was higher than that treated with water extracts for both CC and PF. HPLC was used to analyse 19 phenolic compounds in CC and PF ethanol extracts (CCE and PFE). Results revealed chlorogenic acid and p-coumaric acid in CCE and rosmarinic acid and caffeic acid in PFE. Expression levels of hyaluronan synthase 1 (HAS1), HAS2, HAS3, and aquaporin 3 (AQP3), which are related to skin moisturization, and filaggrin and loricrin, which are related to skin barrier were higher in cells treated with CCE than with PFE. CCE and PFE also increased expression of PPAR-a protein involved in skin moisturization and epidermal differentiation in a concentration-dependent manner. As major components of CCE, chlorogenic acid and p-coumaric acid increased PPAR-a protein expression. Thus, CCE and PFE could be used as functional cosmetic materials for skin hydration and skin barrier effects.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.5
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• pp.110-116
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• 2003

With the growth of aircraft performance and needs for light aircraft, the problems associated with hail impacts on aircraft during flights and grounding become and important issue. These hail encounters can cause severe damages to aircraft and result in major concerns in safety and cost. Since nearly all external components of the commercial and military aircraft-in particular, the nose section and the leading edge of the wing and tail-are subject to damages, much effort has been put into understanding of this problem. However, most of the previous studies have focused on the composite components and few results have been reported for the metallic components. In this paper, we study the ice impacts on the aluminum component with the finite element analysis method utilizing commercial non-linear dynamics solver LS-DYNA. The results are compared with the experimental data and a simple measure of the ice impact effects is proposed.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.3
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• pp.29-37
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• 2000

Because the previous design procedure for the composite wind turbine blade structure using trial and error method takes long time, a improved design procedure by using the program based on classical laminate theory was proposed to reduce the inefficient element. According to the improved design procedure, limitation of strains, stresses and displacements specified by international standard specification IEC1400-1 for the composite wind turbine blade were applied to sizing the structural configuration by using the rule of mixture and the principal stress design technique with a simplified turbine blade. Structural safety for strength and buckling stability was confirmed by the developed analysis program based on the laminate theory to minimize the design procedure. After modifying the preliminary design result with additional structural components such as skin, foam sandwich and mounting joints, stresses, strains, displacements, natural frequency, buckling load and fatigue life were analyzed by the finite element method. Finally these results were confirmed by comparing with IEC1400-1 specification.

• Science of Emotion and Sensibility
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• v.15 no.2
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• pp.177-182
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• 2012

Automotive sub-mat carpet for convenience and comfort of floor administration is additional supplemented floor mat. Sub Mat Backing of the current vehicle's materials reclaimed rubber, PVC, etc. are used, but secondary rubber and PVC Backing have bad sound absorption. Also rubber is heavy too. Contact surfaces between PET staple fiber, PET non-woven, PVC backing and car's floor carpet was measured the coefficient of friction for each sub-mat's non-slip evaluation. A surface of PET non-woven sub-mat has the highest coefficient of friction. Each of sample was observed by optical microscope the contact surfaces before and after. Contact surfaces of PET staple fiber sub-mat was changed increasingly to non-woven. This fact is shown that the sub-mat would be tangled between its contact surface and top of the floor carpet. It is expected to be highly non-slip. In case of PET non-woven sub-mat had not different for contact surfaces between before and after. And PVC backing was shown lower non-slip than other samples. The result of optical microscope and coefficient of friction is seems to be related.