• 한국통신학회논문지
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• 제17권1호
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• pp.68-79
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• 1992

고속 아날로그 시스템,위성통신시스템, video signal processing 및 processing 및 optical fiber interface 회로등에서 높은 전자이동도로 인하여 고주파 툭성이 우수한 GaAs 연산 증폭기는 필수적인 구성 요소이다. 하지만, 낮은 전달컨덕턱스 및 low frequency dispersion등의 현상 때문에 높은 전압이득을 얻을 수 없다는 단점을 가지고 있다. 따라서 본 논문에서는 GaAs MESFETfmf 이용한 증폭기의 이득을 증가시키기 위한 기법을 비교분석하고 기존의 전류미러와 새로운 구성의 전류 미러를 설계하여 회로의 안정화를 꾀하였다. 높은 차동전압이득을 얻기 위하여 단일 증폭기의 bootstrap 이득증가기법을 이용하여 차종입력 회로를 구성하였으며, 회로의 안정도 및 우수한 주파수 특성을 얻기 위하여 common mode feedback을 사용하였다. Pspice를 통한 시뮬레이션 결과 설계된 회로의 이득이 18.6dB 향상되었고 안정도 및 주파수 특성면에서 우수함을 확인할 수 있었다.

• The Journal of Korean Physical Therapy
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• 제14권3호
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• pp.373-406
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• 2002

This study was peformed to investigate the effects on skeletal muscle recovery with aqua-exercise; swimming to take the muscle endurance for 20 days on two group of white rats which were the low extremity atrophy group(control groups) by fixed for two weeks and aqua-exercise group(experimental groups) after it. The effects was observed with light and electron microcope to measure the morphological changes of muscle fibers. The results obtained were as follow. 1. Light microscope: In the case of control groups, quadriceps fibers had been irregular alignment, decreased muscle width and the irregular alignment nuclear appeared, as it is degenerative muscle fibers. In the case of experimental groups, the fibers had been regular alignment cells and fibers. The nucleus of muscle had been normal characterized by oval shape and fiber sarcomere clearly classified. 2. Electron microscope: In the case of control groups, there were the quadriceps which was Z-line streaming phenomenon induced at the sarcomere and cells nuclear separated from basal membrane. It was not only observed the sarcomere alignment irregularly and mitochondria damaged, but also vacuoles found. In the case of experimental groups, A band, I band, H band had been clearly appeared, classified at the myofibrils of quadriceps, and electronic dense M-line found in sarcomere. There were observed satellite cells and basal laminas that usually to be appeared at the time of mitochondrial development, skeletal muscle fiber regeneration or development. This results suggest that the aqua-exercise assisted to inhibit the degenerative morphological changes of skeletal muscle cells and help to recover from abnormal states. Especially, it is considered to effect on a normal structural formation.

• 한국생산제조학회지
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• 제26권2호
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• pp.185-192
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• 2017

In this paper, we reviewed major design parameters for a solid type of deployable antenna and its structural design. We performed modal analysis for a single reflector panel made of aluminum and CFRP (carbon fiber reinforced plastic) to confirm the appropriateness of selected materials. We then predicted the elastic modulus of CFRP using the principles of unidirectional composite elasticity stiffness predictions such as the ROM (Rule of Mixture) and HSR (Hart Smith 10% Rule). To optimize the shape of the antenna reflector, a structural stiffness analysis was performed using derived numerical optimization factors. Six structural stiffness analyses were performed using the constructed experimental design method. The resulting optimal shape conditions are proposed to meet the structural stiffness requirements while minimizing weight.

• 한국전산구조공학회논문집
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• 제27권5호
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• pp.393-401
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• 2014

복합재료 구성성분은 수 마이크로미터 수준의 크기를 가지고 있으므로 시험을 통한 정확한 물성 측정이 매우 어렵다. 그러므로 본 논문에서는 역해석을 이용하여 복합재료 구성성분의 열팽창계수를 예측할 수 있는 기법을 제안한다. 복합재료에 대한 등가 열팽창계수를 예측할 수 있는 Mori-Tanaka 기법과 결합된 역해석기법을 이용하면, 라미나 수준의 목적함수를 최소화함으로써 구성성분의 열팽창계수를 효율적으로 구할 수 있다. 본 연구에서 제안한 기법을 검증하기 위하여 다양한 섬유(glass fiber, P75, P100, M55J)에 대한 열팽창계수를 예측하고 이를 시험결과와 비교하였다. 또한 라미나와 기지 물성치에 대한 불확실성이 섬유 물성치 예측에 미치는 영향을 분석하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제30권11호
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• pp.1620-1632
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• 2017

Objective: This study evaluated the effects of a traditional Chinese medicine formula (TCMF) on muscle fiber characteristics in finishing pigs and the effects of the formula's extract (distilled water, ethyl acetate and petroleum ether extraction) on porcine cell proliferation and isoforms of myosin heavy chain (MyHC) gene expression in myocytes. Methods: In a completely randomized design, ninety pigs were assigned to three diets with five replications per treatment and six pigs per pen. The diets included the basal diet (control group), TCMF1 (basal diet+2.5 g/kg TCMF) and TCMF2 (basal diet+5 g/kg TCMF). The psoas major muscle was obtained from pigs at the end of the experiment. Muscle fiber characteristics in the psoas major muscle were analyzed using myosin ATPase staining. Cell proliferation was measured using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) dye and cytometry. Isoforms of MyHC gene expression were detected by real-time quantitative polymerase chain reaction. Results: The final body weight and carcass weight of finishing pigs were increased by TCMF1 (p<0.05), while the psoas major muscle cross-sectional area was increased by TCMF (p<0.05). The cross-sectional area and diameter of psoas major muscle fiber Ι, IIA, and IIB were increased by TCMF2 (p<0.05). The cross-sectional area and fiber diameter of psoas major muscle fiber IIA and IIB were increased by diet supplementation with TCMF1 (p<0.05). Psoas major muscle fiber IIA and IIB fiber density from the pigs fed the TCMF1 diet and the type IIB fiber density from the pigs fed the TCMF2 diet were lower compared to pigs fed the control diet (p<0.05). Pigs fed TCMF2 had a higher composition of type Ι fiber and a lower percentage of type IIB fiber in the psoas major muscle (p<0.05). The expression levels of MyHC Ι, MyHC IIa, and MyHC IIx mRNA increased and the amount of MyHC IIb mRNA decreased in the psoas major muscle from TCMF2, whereas MyHC Ι and MyHC IIx mRNA increased in the psoas major muscle from TCMF1 (p<0.05). Peroxisome proliferator-activated receptor ${\gamma}$ $coactivator-1{\alpha}$ and CaN mRNA expression in the psoas major muscle were up-regulated by TCMF (p<0.05). Porcine skeletal muscle satellite cell proliferation was promoted by $4{\mu}g/mL$ and $20{\mu}g/mL$ TCMF water extraction (p<0.05). Both $1{\mu}g/mL$ and $5{\mu}g/mL$ of TCMF water extraction increased MyHC IIa, MyHC IIb, and MyHC IIx mRNA expression in porcine myocytes (p<0.05), while MyHC Ι mRNA expression in porcine myocytes was decreased by $5{\mu}g/mL$ TCMF water extraction (p<0.05). Porcine myocyte MyHC Ι and MyHC IIx mRNA expression were increased, and MyHC IIa and MyHC IIb mRNA expression were down-regulated by $5{\mu}g/mL$ TCMF ethyl acetate extraction (p<0.05). MyHC Ι and MyHC IIa mRNA expression in porcine myocytes were increased, and the MyHC IIb mRNA expression was decreased by $1{\mu}g/mL$ TCMF ethyl acetate extraction (p<0.05). Four isoforms of MyHC mRNA expression in porcine myocytes were reduced by $5{\mu}g/mL$ TCMF petroleum ether extraction (p<0.05). MyHC IIa mRNA expression in porcine myocytes increased and MyHC IIb mRNA expression decreased by $1{\mu}g/mL$ in a TCMF petroleum ether extraction (p<0.05). Conclusion: These results indicated that TCMF amplified the psoas major muscle cross-sectional area through changing muscle fiber characteristics in finishing pigs. This effect was confirmed as TCMF extraction promoted porcine cell proliferation and affected isoforms of MyHC gene expression in myocytes.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.649-654
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• 2005

This study proposes a particular approach to assess information about NDVI(Normalized Difference Vegetation Index) and LAI(Leaf Area Index) from the spectroradiometer and NOAA/AVHRR satellite data. AVHRR data were collected in twelves months over a one year period in 2004. We calculated 10-day composite NDVI using daily composite AVHRR surface reflectance products(1km spatial resolution). The 10-day composite NDVI have a great effect on the plant growth conditions. Considerably, NDVI was increased by developing muscle fiber tissue from April to May. Then the NDVI increased until the August and then decreased until February. The highest month was at August and the lower month was at December. The difference NDVI analysis using December and another months data was conducted, the results were provided information on the variation of vegetation coverage. The result suggest that a relationship established between the LAI and NDVI in 2004.

• 산업공학
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• 제16권spc호
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• pp.70-75
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• 2003

There have been dramatic technology changes in telecommunication sector during last two decades. New application services like the introduction of international mobile services, fiber optical home services and satellite personal services are expected to play a major role in the whole field of telecommunication services. In the users' viewpoint, the proper selection and the efficient application of the specific telecommunication service among the various alternatives at hand are recognized as principle means for ensuring the whole business competitiveness. Despite the definite need for the telecommunication service selection strategies, very few researches have been reported in this field. In this paper, attempts are made to identify the companies' decision factors considered in selecting the telecommunication services, to draw the strategic dimensions and categorize each company with respect to the identified dimensions, and to finally find the characteristics of each strategic group in selecting the telecommunication service.

• BMB Reports
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• 제52권1호
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• pp.64-69
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• 2019

The loss of skeletal muscle, called sarcopenia, is an inevitable event during the aging process, and significantly impacts quality of life. Autophagy is known to reduce muscle atrophy caused by dysfunctional organelles, even though the molecular mechanism remains unclear. Here, we have discuss the current understanding of exercise-induced autophagy activation in skeletal muscle regeneration and remodeling, leading to sarcopenia intervention. With aging, dysregulation of autophagy flux inhibits lysosomal storage processes involved in muscle biogenesis. AMPK-ULK1 and the $FoxO/PGC-1{\alpha}$ signaling pathways play a critical role in the induction of autophagy machinery in skeletal muscle, thus these pathways could be targets for therapeutics development. Autophagy has been also shown to be a critical regulator of stem cell fate, which determines satellite cell differentiation into muscle fiber, thereby increasing muscle mass. This review aims to provide a comprehensive understanding of the physiological role of autophagy in skeletal muscle aging and sarcopenia.

• 전자통신동향분석
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• 제33권6호
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• pp.94-106
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• 2018

A quantum key distribution (QKD) provides in principle an unconditional secure communication unlike the standard public key cryptography depending on the computational complexity. In particular, free-space QKD can give a secure solution even without a fiber-based infrastructure. In this paper, we investigate an overview of recent research trends in the free-space QKD system, including satellite and handheld moving platforms. In addition, we show the key components for a free-space QKD system such as the integrated components, single photon detectors, and quantum random number generator. We discuss the technical challenges and progress toward a future free- space QKD system and components.

• 한국어류학회지
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• 제26권3호
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• pp.171-178
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• 2014

로즈마리의 주요 성분인 carnosic acid는 carnosol, rosmarinic acid, ursolic acid 등과 같은 폴리페놀의 한 성분으로 다양한 생리활성 기능이 보고되어 있다. 본 연구에서는 로즈마리 유래 폴리페놀인 carnosic acid가 제브라피쉬 근육성장에 미치는 영향을 근육 내 주사와 사료를 통해서 확인해 보았다. 근육 내 주사 실험을 통해서 CA는 제브라 피쉬의 근육 내 단백질 함량을 증가시키고 중성지방의 함량을 감소시켰다. 또한 조직학적 분석 결과 근섬유의 평균 면적이 커지는 근섬유의 과비대 효과를 나타내었다. 사료 실험 결과 근육 내 단백질 및 중성지방의 함량에는 영향을 미치지 않았으며 조직학적 분석 결과 근육 내 주사 실험에서와 마찬가지로 근 섬유의 과비대를 유도하였다.