• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.1
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• pp.1-11
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• 2020

Medium to large post structures installed along the roadside without proper protection can lead to serious vehicle damage and occupant injury at the impact. In North America and Europe, splitting systems such as slip base or breakaway device are used to reduce impacts. But the system has the risk of secondary accident when the splitted post falls down to the traffic or pedestrian. Sliding Post have been proposed as a way to solve this problem. By studying the crash test results of the 1.3ton and 0.9ton vehicle with 60 km/h and 80 km/h to a Rigidly Fixed Post (RFP) and Sliding Post (SP), danger of the conventional RFP and crashworthiness of the SP have been proven. While collision analysis only from the acceleration measured at the center of the vehicle assumes the motion of the post is the same as that of the vehicle, in this paper, by adding high speed film data to the analysis with vehicle acceleration could have separate the post motion from the vehicle motion. It gives better explanations on the movement of post and vehicle in each distinctive time step and provides basics to the crashworthy post design.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.214.1-214.1
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• 2015

Thin-film transistors (TFTs)의 채널층으로 널리 쓰이는 indium-gallium-zinc oxide (IGZO)는 높은 전자 이동도(약 10 cm2/Vs)를 나타내며 유기 발광 다이오드디스플레이(OLED)와 대면적 액정 디스플레이(LCD)에 필수적으로 사용되고 있다. 하지만, 이러한 재료는 우수한 TFT의 채널층의 특성을 가지는 반면, ZnO 기반 재료이기 때문에 소자 구동에서의 안정성은 가장 큰 문제로 남아있다. 따라서 최근, IGZO layer의 특성을 향상시키기 위한 연구가 다양한 방법으로 시도되고 있다. IGZO의 조성비를 조절하여 전기적 특성을 최적화거나 IGZO layer의 조성 중 Ga을 다른 금속 메탈로 대체하는 연구도 이루어지고 있다. 그러나 IGZO에 미량의 도펀트를 첨가하여 박막 특성 변화를 관찰한 연구는 거의 진행되지 않고 있다. 산화물 TFTs의 전기적 특성과 안정성은 산소 함량에 영향을 많이 받는 것으로 알려져 있으며, 더욱이 TFT 채널층으로 쓰이는 IGZO 박막의 고유한 산소 공공은 디바이스 작동 중 열적으로 활성화 되어 이온화 상태가 될 때 소자의 안정성을 저하시키는 것이 문제점으로 지적되고 있다. 그러므로 본 연구에서는 낮은 전기 음성도(1.22)와 표준전극전위(-2.372 V)를 가지며 산소와의 높은 본드 엔탈피 값(719.6 kJ/mol)을 가짐으로써 산소 공공생성을 억제할 것으로 기대되는 yttrium을 IGZO의 도펀트로 도입하였다. 따라서 본 연구에서는 Y-IGZO의 박막 특성 변화를 관찰하고자 한다. 본 연구에서는 magnetron co-sputtering법으로 IGZO 타깃(DC)과 Y2O3 타깃(RF)를 이용하여 기판 가열 없이 동시 방전을 이용해 non-alkali glass 기판 위에 증착 하였다. IGZO 타깃은 DC power 110 W으로 고정하였으며 Y2O3 타깃에는 RF Power를 50 W에서 110 W까지 증가시키면서 Y 도핑량을 조절하였다. Working pressure는 고 순도 Ar을 20 sccm 주입하여 0.7 Pa로 고정하였다. 모든 실험은 $50{\times}50mm$ 기판 위에 총 두께 $50nm{\pm}2$ 박막을 증착 하였으며, 그 함량에 따른 전기적 특성 및 광학적 특성을 살펴보았다. 또한, IGZO 박막 제조 시 박막의 안정화를 위해 열처리과정은 필수적이다. 하지만 본 연구에서는 열처리를 진행하지 않고 Y-IGZO의 안정성 개선 여부를 보기 위하여 20일 동안 상온에서 방치하여 그 전기적 특성변화를 관찰하였다. 나아가 Y-IGZO 채널 층을 갖는 TFT 소자를 제조하여 소자 구동 특성을 관찰 하였다. Y2O3 타깃에 가해지는 RF Power가 70 W 일 때 Y-IGZO박막은 IGZO박막과 비교하여 상대적으로 캐리어 밀도는 낮은 반면 이동도는 높은 최적 특성을 얻을 수 있었다. 상온방치 결과 Y-IGZO박막은 IGZO박막에 비해 전기적 특성 변화 폭이 적었으며 이것은 Y 도펀트에 의한 안정성 개선의 결과로 예상된다. 투과도는 Y 도핑에 의하여 약 1.6 % 정도 상승하였으며 밴드 갭 내에서 결함 준위로 작용하는 산소공공의 억제로 인한 결과로 판단된다.

• Tuberculosis and Respiratory Diseases
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• v.43 no.4
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• pp.637-644
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• 1996

Interstitial pneumonitis associated with interferon alpha therapy for chronic hepatitis C was first describe6 in 1994 by Kazoo et al In Japan. The mechanism of interstitial pneumonitis developed by interferon alpha was still unknown but immunologic, allergic of direct lung toxicity were suggested. We experienced a case of interstitial pneumonitis developed during interferon alpha therapy for chronic hepatitis C in a 52-year-old male patient. He was treated with 6 million units of interferon alpha intramuscularly 3 times per week for 4 weeks and noted progressive dyspnea and cough. These symptoms were subsided after 6 weeks' discontinuation of interferon alpha therapy. And so, he was retreated with 3 million units of interferon alpha 3 times per week for 8 weeks and felt dyspnea again. He was admitted to our hospital for further evaluation of progressive dyspnea. Arterial blood gas(ABG) values were $PaO_2$ 90.7 mmHg and $PaCO_2$ 31.9 mmHg, and antinuclear antibody(ANA) was negative. A chest X-ray film revealed diffuse reticulo-nodular shadows in bilateral lung fields, suggesting a diagnosis of interstitial pneumonitis. A marked increase in lymphocyte count and suppressor T cell were observed in bronchoalveolar lavage(BAL) fluid. Lymphocyte stimulation test with interferon alpha was positive. Interstitial pneumonitis was confirmed by transbronchial lung biopsy. After discontinuation of interferon alpha, we gave oral steroid in the condition that clinical symptoms were being improved gradually.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.6
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• pp.621-629
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• 2008

This paper presents a low temperature co-fire ceramics(LTCC) Upconverter for a Ka-band OBS satellite transponder in order for size reduction which is one of the most important requirement for satellite components. A S-band low-pass filter(LPF), a K-band band-pass filter(BPF), and an upconverting MMIC mixer are embedded in the multi-layer structure of the upconverter. All spurious can be selectively rejected by employing a modified Elliptic low pass filter with a multi-pole structure for the S-band LPF. Also an improved performance of out-of-band rejection can be obtained. At the K-band BPF design a layer coupled configuration is employed. The upconverting mixer is an MMIC diode mixer with a double-balanced configuration. Conversion loss and isolation of the upconverter are 9 dB and 51 dBc, respectively. The size of the LTCC upconverter is only $8{\times}7{\times}0.6mm^3$ which is one-third for the thin-film based upconverter.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.1
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• pp.92-97
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• 2005

Inhibition of inflammatory response, acceleration of basal cell growth, and balanced synthesis of extracellular matrix (ECM) are important in healing of cutaneous open wounds. In order to evaluate the healing effects of water extracts of Radix Astragali (the root of Astragalus membranaceus (Fisch.)) on open wound at early stage, the experimental open wounds were generated on the dorsal sides of SD rats under anesthesia. The boiled-water extracts of Radix Astragali $(100{\mu}l)$, soaked into an occlusive film dressing were applied once a day for eleven consecutive days. The healing process was assessed by measuring macroscopic appearance and wound areas of the open wounds. The molecular aspects of healing process by Radix Astragali extracts were also investigated by Hematoxylin-Eosin (H-E) double staining and immunohistological staining of collagen type I in the healed skin area, implying cell density and linear alignment of the granulation tissue, and ECM synthesis and its remodeling, respectively. The Astragali radix extracts were found to significantly accelerate the cutaneous wound healing by suppressing the inflammation and stimulating the basal cell growth in wounded area, as compared to epidermal growth factor (EGF).

• Applied Biological Chemistry
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• v.24 no.4
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• pp.218-223
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• 1981

This study was conducted to investigate the effects of post-harvest drying method and subsquent storage condition on the quality of garlic bulbs for 10 months from July, 1980 to April, 1981. The 27% weight loss of garlic bulbs by HPHD (hot air post-harvest frying) for 12 days at $40^{\circ}C$ (8hrs/day) was equal to that by NPHD (conventional natural post-harvest drying) for 35 days. But the decay occured 5.5% only in NPHD. During the storage period of garlic bulbs by HPHD, their decay and weight ]oss were less 25.4% and 13.5% in ambient storage, and less 14.2% and 7.5% in low temperature storage than those of NPHD. When garlic bulbs were stored in low temperature, the weight loss and decay were less 20.0% and 22.4% in NPHD, and tess 14.0% and 9.9% in HPHD than those in ambient temperature storage. The Quality of garlic bulbs packed with 0.08mm polyethylene film stored at ambient temperature for 2 months was so poor as to be inedible because of the adverse effect of $CO_2$ and the growth of molds, but in low temperature storage for 10 months it was in good shape showing the weight loss, the decay and the sprouting 2.6%, 3.4% and 26.8%, respectively.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.58-58
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• 2011

CNT 나노기술을 응용한 IT산업용 적층간지용 ESD(정전방전, Electrostatic Dissipation)PU 발포필름의 제조 가공기술 및 상품화 개발은 전자제품 패키지에 요구되는 쿠션성과 정전방전 기능을 갖는 폴리우레탄 발포 필름의 제조기술을 확립함으로써 가능 할 수 있다. 특히 IT산업용 필름제품이 개발되면 ESD 성능을 발휘하게 됨으로서 정전기 쇼크에 의한 각종 전자제품의 오작동이나 파손 방지가 가능하게 되어 포장재, 자동차, 전자제품의 하우징 등으로 사용될 수 있게 된다. 현재까지 ESD 기능을 부여하기 위해서 사용되는 충전재로는 금속섬유, 금속플레이크, 탄소섬유, 카본블랙 등이 있으며, 최근 탄소나노튜브를 응용한 연구가 많이 진행되고 있는데 탄소나노튜브는 직경이 수십nm, 종횡비 1000이상의 나노섬유형태로 서 전기전도성이 구리수준으로 알려져 있고 소량을 충전할 시 기계적 특성도 오히려 증대하는 장점을 가지고 있으며 전기적 특성으로는 상대적으로 낮은 나노튜브 함량에서는 ESD를 들 수 있고 높은 함량에서는 전자파 차폐성까지 기대되고 있다. 본 연구에서는 우수한 인장강도, 기계적 강도, 열적 안정성, 내약품성을 가지면서 습식 또는 용융공정을 통해 용이하게 시트, 필름, 코팅제를 제조할 수 있는 방수, 투습방수성을 가지는 유연재료인 폴리우레탄(PU) 1액형 PU에 MWNT 함량이 3wt%인 IPA/MWNT 분산용액을 PU 함량 대비 20, 30, 40파트로 함유시켜 $120^{\circ}C$에서 2분 건조시켜 제조한 그라운드 필름에 2액형 PU와 IPA/MWNT 분산용액에 발포제를 첨가하여 발포온도 140, 150, $160^{\circ}C$에서 5분간 건조시켜 시료 필름을 제조하였다. 제조된 필름의 전기전도성 측정은 부피저항과, 표면저항을 각각 측정하여 확인하였으며, 필름의 마찰 대전압은 E.S.T-7 마찰 대전압 시험기를 이용하여 표면 마찰 대전압과 반감기를 측정하여 확인하고, 필름의 물리적 특성은 인장시험기를 이용하여 breaking stress, breaking strain을 구하였다. 필름의 표면 특성은 영상 현미경 시스템을 사용하여 ${\times}1000$ 배율로 측정하여 분산특성과의 연관성을 확인하였다.

• Food Science and Preservation
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• v.15 no.6
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• pp.804-809
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• 2008

Modified atmosphere packaging (MAP) was assessed in terms of extending the shelf life of Solidago virgaurea spp. gigantea. In June 2005 Solidago virgaurea spp. gigantea were harvested from Ulleung Island, packaged in $30\;{\mu}m$ PP, $30\;{\mu}m$ Antifogging-OPP, $30\;{\mu}m$ LDPE, $18\;{\mu}m$ Macroperforated-HDPE, $60\;{\mu}m$ nylon/PE, or $85\;{\mu}m$ PVC/PE film, then stored at 4, 10 or $20^{\circ}C$ for up to 14 days. The $O_2$ concentration decreased to $9{\sim}10%$ in the PP and A-OPP packaging, to $12{\sim}16%$ in LDPE packaging, and to 2% in nylon/PE and PVC/PE packaging at $10^{\circ}C$. The $CO_2$ concentration increased to 5% at $10^{\circ}C$ in PP, A-OPP and LDPE packaging, but increased consistently in the nylon/PE and PVC/PE packaging. Weight loss was markedly reduced by all MAP films except M-HDPE, and which was enhanced with decreasing storage temperature. The soluble solids and pH were not affected by the packaging material at $4^{\circ}C$ and $10^{\circ}C$, but were affected at $20^{\circ}C$. The highest score for sensory qualities (appearance, color and overall acceptability) was obtained for vegetables stored at $4^{\circ}C$ in PP films. Our results show that MAP using PP films and $4^{\circ}C$ storage can effectively maintain the quality of Solidago virgaurea spp. gigantea.

• Journal of Pharmaceutical Investigation
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• v.27 no.4
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• pp.287-293
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• 1997

To make a stable o/w emulsion, the effects of egg lecithin as an emulsifier and polyvinylpyrrolidone (PVP) as an auxiliary emulsifier on the physical stability of emulsion were investigated. The oil-in-water emulsion system was manufactured by microfluidizer and evaluated the physical stability. Average particle size and size distribution of emulsion was measured by dynamic light scattering analyzer and interfacial tension was measured. From the interfacial tension tested, critical micelle concentration of the egg lecithin was 0.1 %w/v and optimal concentration for the preparation of emulsion was 1.0 %w/v. The mean particle size was about $0.2\;{\mu}m$ which was suitable for injections. The short-term accelerated stability studies were conducted by centrifugation, freeze-thaw method and shaking of the emulsion samples. The addition of PVP was caused the reduction in the particle size and improved the physical stability of emulsion. These results suggested that a mixed interfacial film comprising the egg lecithin and PVP was formed at the o/w interface and it was effective in preventing phase separation under thermic or mechanical stress. We used antineoplaston A10 (A10) as a model drug which is peptide and amino acid derivative having a action to the living organism against the development of neoplastic growth by a nonimmunological progress. It has a poor solubility in water and there may be a difficulty in formulation of A10. Emulsion formulation study about A10 was performed. Solubility of A10 in emulsion was about five times as high as that in water. From the results of solubility and partition coefficient, almost A10 molecules in o/w emulsion exist in the interface between oil and water.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1996.05a
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• pp.91-115
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• 1996

In the recent years, protected horticultural facilities have been modernized and glasshouses are also propagating in Korea, even most vegetables production are conducted in the traditional plastic houses covered with, for example, PVC film for just temperature keeping. It would limit the productivity and competitivity of the vegetable production industry without automatization and high quality year round production. A plant factory, aimed to produce vegetables in the limited areas, was initiated in Christensen farm, Denmark in 1957, and widely propagated in some developed countries. As it has the automatized system which enables to keep optimized environment conditions, it will be the best facility for high quality products as well as year round planned production. However, we have not even started the plant factory production. Since the plant factory is requiring lots of resources, besides plant cultivation technologies, such as environment control, automatic engineering and robotics, our approach to the development of plant factories should be minded on Practical Plant Factories considering our current farming practices and least capital needs rather than blindly employing the advanced technologies from developed countries. Thus, Korean plant factory development can be initiated with year round leaf vegetables production in NFT or DFT cultivation system instead of the moval bed system, in which aerial environment factors such as light, temperature, humidity and CO$_2$ concentration and root environment ones such as solution concentration, temperature, pH and water soluble oxygen shall be automatically controlled. And the seeding, seedling and transplanting operations shall be accomplished in the house entrance, and the harvesting and grading opreations shall be conducted in the house exit. For practical plant factories, environment control technologies including artificial light source, illumination and air conditioning, automatic management for nutrient solution and automatic production line of moval bed system, transplanting and harvest should be developed along with researches on the cost reduction of factory building construction.