• 한국통신학회논문지
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• 제30권3B호
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• pp.53-64
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• 2005

Rapid growth of digitalization in telecommunication and broadcasting and remarkable enhancement in broadband and high speed transmission capability of media raised a problem of integrating communication and broadcasting. In order to implement this, the government has selected construction of Broadband Convergence Network (BcN) as a main new growth engine of the country. The BcN will be realized based on FTTH and Broadband Home Network (BHN) will be implemented through this solution. Transfer rate and bandwidth required for the BcN to be constructed aiming at integration of communication and broadcasting will be specified and the performance of basic transmission media, the plastic optical fiber, will be discussed in order to present its appropriateness.

• ETRI Journal
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• 제28권4호
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• pp.533-536
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• 2006

A distributed Bragg reflector (DBR) laser and a high speed electroabsorption modulator (EAM) are integrated on the basis of the selective area growth technique. The typical threshold current is 4 to 6 mA, and the side mode suppression ratio is over 40 dB with single mode operation at 1550 nm. The DBR laser exhibits 2.5 to 3.3 mW fiber output power at a laser gain current of 100 mA, and a modulator bias voltage of 0 V. The 3 dB bandwidth is 13 GHz. A 10 Gbps non-return to zero operation with 12 dB extinction ratio is obtained. A four-channel laser array with 100 GHz wavelength spacing was fabricated and its operation at the designed wavelength was confirmed.

• 한국군사과학기술학회지
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• 제11권5호
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• pp.107-115
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• 2008

In this paper, we have proposed a wear growth prediction method on the surface of rubber pad of track assembly installed in high-speed battle tank i.e. the automatic model updating code interfacing with commercial finite element simulation software. Also, simple and resonable geometrical, material finite element model was established to be easily updated based on the empirical threshold value of contact pressure on the contact surface. From the iterative model update and analysis results, we discovered a weak point on rubber pad surface and suggested a new design concept for improving the wear performance of track assembly.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.2270-2277
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• 2010

Recently the role of a railroad is emphasized as the imprortant part for growth for the low carbon green growth and the social consensus about the railroad investment is actively progressed. The various social economic value in which the travel demand change over of the environment-friendly railroad system can bring becomes with public debate as much as a discussion is not any more necessary. In this research, the influence that it recognized that the travel time improvement by the high speed rail was the most important element among many method that it can increase the railroad use efficiency in which it connects the interregional major cities and the railway travel time improvement reaches to the rate of railway and road travel time, and the environment like the carbon emission quantity was comprehensively inquired.

• Corrosion Science and Technology
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• 제10권4호
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• pp.151-155
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• 2011

The iron oxide particles could be resulted from the corrosion of the circulating water system of a power plant. Because it may be one of the trouble materials which affect the power generation efficiency due to the deposition on steam generator tube and turbine blade, the continuous observation of its concentration is very important. The laser induced break-down detection (LIBD) technology was applied to monitor continuously the concentration of corrosion products with the detection limit of ppb level. The measurement system consists of a Nd:YAG pulsed laser, a polarizing beam splitter, a flow-type sample cell, an acoustic emission sensor, a high speed data acquisition board, a personal computer, etc.. The performance test results confirmed that this technology can be effective to monitor the corrosion product concentration of the circulating water system of a power plant.

• International Journal of Automotive Technology
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• 제6권3호
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• pp.229-234
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• 2005

The dynamic crack growth in ductile steel is investigated by means of the impact loaded 3 point bending (3PB) specimens. Results from experiments and numerical simulations are compared to each other. A modified 3PB specimen designed with the reduced width at its ends has been developed in order to avoid the initial compressive loading of the crack tip and also to avoid the uncertain boundary conditions at the impact heads. Numerical simulations of the experiments are made by using a finite element method (FEM) code, ABAQUS. The high speed photography is used to obtain the crack growth and the data of the crack tip opening displacement (CTOD). The direct measurements of the relative rotations of two specimen halves are made by using the Moire interference pattern.

• 한국IT서비스학회지
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• 제7권1호
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• pp.45-62
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• 2008

This review examines the rapid growth of qualitative and quantitative of telecommunication industry for past couple of years from customer's viewpoint. Most of the telecommunication products were positioned in the market by the businesses and government's support, but the entity of telecommunication products were never interpreted from the user's viewpoint. Even though, various kinds of telecommunication services have been actively discussed by businesses, government, and IT professionals, it has not been sufficiently discussed by the marketing academia where they need to focus a lot on customer's utility. For the purpose of providing an insight of the telecommunication service marketing strategy, this study looked over old and new directions of growth, failure and evolution of services by focusing on two main pillar of communication business, which is high-speed internet and mobile phone service. Additionally, the research explains and mentions the limit and trend of the telecommunication service marketing, and the future research task that needs to be solved.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.230.3-231
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• 2003

The therapeutic use of protein pharmaceuticals produced by recombinant DNA technology is increasing in recent decades. In order to investigate the quality of recombinant proteins, it is important to identify and assign the impurities produced in the process of recombination or in storage conditions. Capillary Electrophoresis is emerging technology exhibiting high sensitivity, selectivity and speed and may be most powerful tools for this application. In this study, human growth hormone (hGH) has been analyzed by various mode of capillary electrophoresis such as capillary zone electrophoresis (CZE), capillary gel electrophoresis (CGE), and capillary isoelectric focusing (cIEF) to indicate the chemically or biologically oriented variants and the degraded fragments. (omitted)

• 한국자원식물학회지
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• 제27권5호
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• pp.546-555
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• 2014

연구의 최종 목표는 실내의 공간과 특성에 따라 효율적으로 실내공기질을 향상시킬 수 있는 식물 녹화와 바이오필터를 통합한 시스템의 개발이다. 그러나 이러한 목표를 달성하기 위해서는 바이오필터 시스템의 적절한 공기정화량에 대한 용량 설계에 중요한 영향을 주는 일정한 압력손실량과 토양수분 함량과 같은 여러 가지 요구사항들이 충족되어야 한다. 따라서 본 기초 연구는 바이오필터의 토양 내 균일한 분포를 갖는 토양수분 함량과 압력손실량을 유지하고 정상적인 식물 생장 특히 바람에 의한 근권부 스트레스를 받지 않도록 풍속을 적절히 조절하고, 바이오필터 내 초기 토양수분 함량이 일정하게 유지되어 안정성을 확보하기 위해 수행되었다. 본 실험에서는 평면형 바이오필터 모델을 설계하여 제작하고 세 가지 풍속(1, 2, $3cm{\cdot}sec^{-1}$)에 따른 바이오필터의 공기정화량, 공기체류시간, 기액비를 산출하였다. 또한 세가지 풍속에 따라 바이오필터 내 토양층을 통과하여 배출된 가습공기의 상대습도, 압력손실량, 토양수분 함량을 측정하고, 이 바이오필터 내에서 자란 상추와 더 피고사리의 생육을 평가하였다. 풍속 실험의 결과, 풍속 $3cm{\cdot}sec^{-1}$가 상대습도, 토양수분 함량, 식물생육을 유지하기에 가장 적절하였다. 따라서 다음 실험에서는 풍속을 $3cm{\cdot}sec^{-1}$로 고정하고 두 가지 수준의 초기 토양수분 함량(저수준 18.5%, 고수준 28.7%) 조건에서 바이오필터를 가동한 처리구와 바이오필터를 가동하지 않은 대조구(초기 토양수분 함량 29.7%)를 설정하고, 바이오필터 내 토양층을 통과하여 배출된 가습공기의 상대습도, 압력손실량, 토양수분 함량과 바이오필터 내에서 자란 상록넉줄고사리의 생육을 평가하였다. 이 실험 결과는 첫 번째 실험 결과와 유사하였으며 상대습도, 토양수분 함량, 압력손실량이 일정한 수준을 유지하였다. 또한 세 가지 초기 토양수분 함량에 따른 상록넉줄고사리의 생육도 유의성 있는 차이를 나타내지 않았다. 그러나 두 가지의 바이오필터 처리구는 대조구에 비해 건물중이 다소 증가된 것을 알 수 있었다. 따라서 주요 물리적 요소인 토양수분 함량과 압력손실량을 유지할 수 있는 본 바이오필터 시스템의 안정성은 가까운 미래에 보다 발전된 일체형 바이오필터 모델 설계에 적용될 수 있을 것으로 판단된다.

• 한국결정성장학회지
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• 제28권5호
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• pp.217-221
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• 2018

Selective laser melting(SLM)은 적층 제조 방법 중 하나로서, 분말을 선택적으로 용융하여 기능적이고, 복잡한 형상을 즉각적으로 제작 가능하다는 장점이 있다. Ti-6Al-4V 합금의 경우 높은 융점과 산화문제로 인하여 SLM 공정도입에 어려움을 겪고 있다. 본 연구에서는 SLM 장비를 사용하여 Ti-6Al-4V 파트를 성공적으로 적층하였으며 스캔속도, 레이저 파워의 변수를 조절하여 적층 가능 조건을 도출하였다. 또한 적층 된 Ti-6Al-4V 파트의 형상 정밀도, 면밀도 및 기계적특성 평가를 통하여 일반적으로 사용되는 공정조건(스캔 속도 200~700 mm/s)으로 제작된 제작품 물성치와 비교를 통해 Ti-6Al-4V 합금의 고속 적층 영역에서의 최적 공정을 확립하였다.