• Journal of Nutrition and Health
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• 제39권7호
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• pp.599-609
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• 2006

In this study, we investigated the in vivo effect by intake of the irradiated foods such as mackerel and sesame seed which are high in unsaturated fatty acid through TBARS (thiobarbituric acid reactive subtance) and the tissue pathological and genotoxicological test. Thirty two ICR mice are divided into four groups, one non-irradiated (control) group and three irradiated (5, 10, 20 kGy, respectively) groups. Sesame seed and pulverized mackerel in modified AIN93M diet were mixed together then divided into four identical parts. Three parts of them were irradiated by doses of 5, 10, and 20 kGy. These experimental diet were fed to each group for 4, 8 and] 6 weeks. The results of the study were as follows: No significant differences in weight gain were found in each group. Peroxide value of the irradiated diet was higher than that of the non-radiated one and also increased according to the storage period. TBA values in plasma, liver, kidney and Peyer's patch were not significantly different among 4 groups. DNA% in tail, tail length (TL) and tail moment (TM) values of the blood lymphocyte in 4, 8 and 16 week groups and the liver in 16 week group were much measured over the control DNA % in tail of kidney of 8 week group was significantly than the control and TL and TM of 8 week and TM of 16 week groups showed a tendency of higher values. By Peyer's DNA % in tail of 8 week group, DNA % in tail and TM of 16 week groups increased significantly over the control, Ultrastructural examination shows myeline figures and swollen mitochondria in parietal cells and intestinal epithelial cells of 8 and 16 weeks groups. After this study, we need further investigations on the safety of highly consumed foods which contain high contents of unsaturated fatty acid, largely imported and which are possible to be irradiated.

• 환경생물
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• 제24권1호
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• pp.46-52
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• 2006

세포에 미치는 염화수은(II)과 이온화 방사선의 영향과 수은 처리 전 후 방사선 조사 시 그 상호 작용에 관해 알아보고자 본 연구를 수행하였다. 염화수은(II)의 독성정도를 알아보기 위하여 사람의 자궁암 세포에 농도별로 염화수은(II)을 처리하였다. 세포의 생존율은 3가지 농도(1,0. 1,0. $0.01\;{\mu}M$)모두에서 유의하게 감소하였으며 이미 $0.1\;{\mu}M$에서 약 73%의 생존율이 감소하는 것으로 나타났다. 염화수은(II)과 방사선의 단독처리 시 DNA의 손상 정도에 비해 복합처리 시의 DNA손상 정도가 $2\sim4$배 정도 확연히 높아짐을 볼 수 있었다. 특히 방사선 후 수은 처리군은 DNA손상의 정도가 다른 처리군에 비하여 높게 나타났는데 이는 이미 기존의 보문에서 밝혀진 바와 같이 수은의 DNA수복에 관련되어 있는 Fpg protein에 미치는 영향 때문으로 사료된다. 이미 방사선에 의해 산화적 손상을 입은 DNA의 수복 기작을 수은이 방해하여 좀 더 높은 손상을 가져오는 것을 확인할 수 있었다.

• Wind and Structures
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• 제29권6호
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• pp.457-469
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• 2019

In this paper, a numerical solution is presented for supersonic flutter analysis of cantilever non-symmetric functionally graded (FG) sandwich plates. The plate is considered to be composed of two different functionally graded face sheets and an isotropic homogeneous core made of ceramic. Based on the first order shear deformation theory (FSDT) and linear piston theory, the set of governing equations and boundary conditions are derived. Dimensionless form of the governing equations and boundary conditions are derived and solved numerically using generalized differential quadrature method (GDQM) and critical velocity and flutter frequencies are calculated. For various values of the yaw angle, effect of different parameters like aspect ratio, thickness of the plate, power law indices and thickness of the core on the flutter boundaries are investigated. Numerical examples show that wings and tail fins with larger length and shorter width are more stable in supersonic flights. It is concluded for FG sandwich plates made of Al-Al₂O₃ that increase in volume fraction of ceramic (Al₂O₃) increases aeroelastic stability of the plate. Presented study confirms that improvement of aeroelastic behavior and weight of wings and tail fins of aircrafts are not consistent items. It is shown that value of the critical yaw angle depends on aspect ratio of the plate and other parameters including thickness and variation of properties have no considerable effect on it. Results of this paper can be used in design and analysis of wing and tail fin of supersonic airplanes.

• 한국콘텐츠학회논문지
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• 제21권8호
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• pp.69-78
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• 2021

디지털 기술발전과 더불어 극장이 아닌 디지털 온라인 매체에서의 영화 수요와 공급이 지속적으로 증가하고 있다. 본 연구는 극장에 비해 다양한 영화가 상영되는 디지털 온라인 영화시장의 수요 집중화 경향을 분석하고자 한다. 2013년 1월부터 2019년 12월까지 TV VOD 자료에 대한 실증분석을 통해 다음의 결과를 확인하였다. 첫째, 극장개봉작 1,137편의 영화에 대한 분석을 통해 디지털 온라인 매체인 TV VOD 관람 수요에 비해 극장 관람 수요의 집중도가 상대적으로 더 높음을 확인하였고 이러한 차이가 통계적으로도 유의하게 나타났다. 둘째, TV VOD 수요 집중도 추이를 살펴보면, 시장에 공급되는 작품편수가 증가함에 따라 절대적 롱테일 지수에 해당하는 독립·예술영화(틈새 상품) 수요도 증가하는 추이를 보이지만 상대적 롱테일 지수인 독립·예술영화 수요 비중과 상위 1% 영화의 수요 비중의 경우 증가 또는 감소 추이가 뚜렷하게 나타나지 않았다. 셋째, TV VOD 수요 집중도와 TV VOD 시장규모 간에 통계적으로 유의한 관계가 있다고 보기 어려웠다. 본 연구는 우리나라의 디지털 온라인 영화시장의 특징을 파악할 수 있는 실증적 결과들을 제시하였다는 점에서 유용성을 가질 것이다.

• 동의신경정신과학회지
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• 제15권1호
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• pp.101-119
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• 2004

Ginseng Radix Alba and Cyperi Rhizoma were investigated for their anti-depressant effects. For this purpose, forced-swimming test, tail suspension test, hot plate test, reserpine-induced hypothermia, aggressive behavior test were performed. In addition, the brain content of 5-hydroxyindoleacetic acid(a metabolite of serotonin), the monoamine oxidase activity, anticonvulsant effect, sleep enhancement effect were determined. The results are as follows: In the forced swimming test, Ginseng Radix diminished the duration of immobility by 45.5% compared to the control group, while Cyperi Rhizoma showed weaker effect (12.4% reduction) at 2g/kg. In the tail suspension test, the effect of Ginseng Radix(43.7% reduction) are also better than that of Cyperi Rhizoma(15.6% reduction) at 2g/kg. In the hot plate test, Ginseng Radix showed no difference as compared to control, while Cyperi Rhizoma increased the jump latency time by about 25% after administration for 10 days. In the reserpine-induced hypothermia test, both drugs slowly dropped the body temperature compared to the control group, especially the rate of hypothermia of Ginseng Radix was 24.0% at 1g/kg. In the aggressive behavior test, both drugs delayed the onset time, decreased the duration and frequency, of which effects were better in Cyperi Rhizoma. The content of 5-hydroxyindoleacetic acid in mice brain was slightly increased in Ginseng Radix, while Cyperi Rhizoma increased its level almost to the control group. Both drugs inhibited the monoamine oxidase activity in a dose-dependent manner, but the effect(51.2%) of Cyperi Rhizoma was more potent than the effect(11.8%) of Ginseng Radix. In the pentobarbital-induced sleep test, Cyperi Rhizoma exhibited no significant difference against the control group, while Ginseng Radix showed about two-fold enhancement at 2g/kg. The anticonvulsant effect of both drugs delayed the onset time, shortened the duration of convulsion and diminished the lethality, but Ginseng Radix were better than Cyperi Rhizoma.

• Journal of Nutrition and Health
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• 제50권1호
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• pp.10-24
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• 2017

본 연구는 건강한 성인 남녀를 대상으로 glutathione S-transferase (GST)M1 및 T1 유전자 다형성에 따라 한식에서 주로 섭취하는 식물성 식품군과 한식 식단의 DNA 손상 감소효과를 측정하여 유전적 민감도가 어떻게 나타나는지를 알아보기 위해 수행되었다. 이를 위하여 건강한 성인 남녀 59명을 대상으로 혈액을 채취하여 GST genotype을 분류하였으며 그 중 17명을 선발하여 DNA 손상 감소효과를 Comet assay를 이용하여 측정하였고 DNA damage relative score로 나타냈다. 제 5기 2차년도 국민건강영양조사를 활용하여 한국인이 많이 섭취하는 식물성 식품을 10가지 식품군 (감자류, 견과류, 곡류, 과일류, 김치류, 두류, 버섯류, 오일류 채소류 해조류)으로 분류 후, 각 식품군별 총 섭취량의 1% 이상을 섭취한 84종의 식품을 한식 식물성 식품으로 최종 선정하였으며 한식 식단 (Korean diet)은 한국영양학회에서 발행한 [2010 한국인 영양섭취 기준]에 제시되어 있는 1주일 표준식단 (2,000 kcal/day)을 사용하였다. GSTM1 유전자 다형성에 따른 한식 식물성 식품군의 Tail moment로 본 DNA 손상 감소효과는 곡류와 오일류에서만 GSTM1 wild type보다 mutant type에서 유의하게 높았다. 이에 비해 DNA 손상 감소 효과를 % DNA in tail과 Tail moment로 본 결과, 견과류 과일류 채소류 버섯류 김치류 해조류에서 GSTT1 mutant type에 비해 wild type에서 유의하게 더 높게 나타났다. GSTM1과 GSTT1의 combined genotype에 따라 한식 식물성 식품의 DNA 손상 감소효과를 본 결과, 과일류, 김치류, 버섯류, 채소류, 해조류는 1군 (GSTM1+/GSTT1+) 및 3군 (GSTM1-/GSTT1+)에서, 오일류는 3군 (GSTM1-/GSTT1+)에서 DNA 손상 감소 효과가 유의하게 높았으며. 감자류, 견과류, 곡류, 두류, Total은 DNA 손상 감소 효과가 2군 (GSTM1+/GSTT1-) 및 3군 (GSTM1-/GSTT1+)에서 유의하게 높아 식품군에 따라 GST 유전자 다형성에 따른 DNA 손상 감소효과가 다르게 나타나는 것을 확인할 수 있었다. 한식 식단은 DNA 손상의 세 가지 지표인 % DNA in tail, Tail moment, Tail length로 측정해본 결과 GSTM1의 경우 wild type에서 mutant type보다 더 크게 나타났으며, GSTT1의 경우는 genotype에 따라 DNA 손상이 달라지는 경향은 있었지만 유의한 차이를 나타내지 않았다. 결론적으로 한식에서 주로 섭취하는 식물성 식품군에서는 식품에 따라 부분적으로 GSTM1은 mutant type에서, GSTT1은 wild type에서 DNA 손상 보호효과가 더 크게 나타났으며, GSTM1과 GSTT1의 combined genotype에 따른 DNA 손상 보호효과는 식품군에 따라 다르게 나타났다. 반면, 한식 식단에서는 DNA 손상 보호효과가 GSTM1 wild type에서 mutant type보다 더 크게 나타났으며, GSTT1 genotype에는 영향을 받지 않는 것으로 나타났다. 이와 같은 결과는 한식 식물성 식품군 및 식사패턴의 항산화 기능 우수성을 증명하는 기초자료가 될 것이며, 나아가 개인별 유전자에 따른 항산화 맞춤영양연구를 시작하는 시발점이 될 수 있을 것이다. 앞으로 GST 유전자 다형성에 따른 한식과 한식 식물성 식품군의 유전적 민감도를 더 명확하게 규명하기 위해서는 대상 인원을 늘려 수행하는 광범위한 연구가 필요할 것으로 보인다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.477-478
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• 2016

This paper introduces a repetitive controller in low switching frequency applications. Generally, A high power UPS system has a high rated current. And the system usually consist of high power IGBT has a tail current. So the high power UPS system operates in low switching frequency because of this tail current. The repetitive controller improve THD of output voltage or current by reducing the steady state error. The effect of the repetitive controller is proved by simulations.

• JSTS:Journal of Semiconductor Technology and Science
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• 제7권2호
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• pp.82-87
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• 2007

The electrical properties of metallic junction diodes and metallic source/drain (S/D) Schottky barrier metal-oxide-semiconductor field-effect transistor (SB-MOSFET) were simulated. By using the abrupt metallic junction at the S/D region, the short-channel effects in nano-scaled MOSFET devices can be effectively suppressed. Particularly, the effects of trap states at the metal-silicide/silicon interface of S/D junction were simulated by taking into account the tail distributions and the Gaussian distributions at the silicon band edge and at the silicon midgap, respectively. As a result of device simulation, the reduction of interfacial trap states with Gaussian distribution is more important than that of interfacial trap states with tail distribution for improving the metallic junction diodes and SB-MOSFET. It is that a forming gas annealing after silicide formation significantly improved the electrical properties of metallic junction devices.

• 대한기계학회논문집B
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• 제29권3호
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• pp.295-305
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• 2005

To improve the aerodynamic effciency of TR-E2, a new configuration so called TR-E2Sl was introduced. TR-2251 is composed of different wing airfoil section and T-tail shape compared with TR-E2. Wind tunnel test for TR-EBS1 had been performed by changing the incidence angles of wing and deflection angles of control surfaces such as elevator and rudder. Also the on/off effect of ventral fin attached underneath of AFT fuselage was tested. Test result showed that variations of wing incidence angle did not cause any severe differences in aerodynamic characteristics. Longitudinal and directional characteristics of TR-E2S1 show stable for the pitch and yaw motions. However, the lateral stability of TR-E2S1 is not stable for a certain control surface deflection.

• International Journal of Aerospace System Engineering
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• 제6권1호
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• pp.1-7
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• 2019

In the present study, structural safety and stability on the main wing and tail planes of the 1.2 ton WIG(Wing in Ground Effect) flight vehicle, which will be a high speed maritime transportation system for the next generation, was performed. The carbon-epoxy composite material was used in design of wing structure. The skin-spar with skin-stressed structural type was adopted for improvement of lightness and structural stability. As a design procedure for this study, the design load was estimated with maximum flight load. From static strength analysis results using finite element method of the commercial codes. From the stress analysis results of the main wing, it was confirmed that the upper skin structure between the second rib and the third rib was unstable for the buckling load. Therefore in order to solve this problem, three stiffeners at the buckled region were added. After design modification, even though the weight of the wing was a little bit heavier than the target weight, the structural safety and stability was satisfied for design requirements.