• 한국전기전자재료학회논문지
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• 제21권6호
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• pp.499-502
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• 2008

In this work, Ga-doped ZnO (GZO) thin films for gas sensor application were deposited on low temperature co-fired ceramics (LTCC) substrates, by RF magnetron sputtering method. The LTCC substrate is one of promising materials for this application since it has many advantages (e.g., low cost production, high manufacturing yields and easy realizing 3D structure etc.). The LTCC substrates with thickness of $400\;{\mu}m$ were fabricated by laminating 12 green tapes which consist of alumina and glass particle in an organic binder. The structural properties of the fabricated GZO thin film with thickness of 50 nm is analyzed by X-ray diffraction method (XRD) and field emission scanning electron microscope (FESEM). The film shows good adhesion to the substrate. The GZO gas sensors are tested by gas measurement system and show fast response and recovery characteristics to $NO_x$ gas that is 27.2 and 27.9 sec, recpectively.

• Journal of Mechanical Science and Technology
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• 제15권6호
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• pp.804-812
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• 2001

A triboelectrostatic separation system for removing unburned carbon from coal fly ash is designed and evaluated. Fly ash from a coal-fired power plant is used as an accepted additive in concrete where it adds strength, sulfate resistance and reduced cost, provided acceptable levels of unburned carbon are maintained. Unfortunately, unburned carbon in coal fly ash absorbs some of other additives and reduces the concrete strength. This paper describes to investigate dry triboelectrostatic process to separate unburned carbon from coal fly ash and utilize it into economically valuable products. The laboratory-scale triboelectrostatic separation system consists of a particle feeding system, a tribocharger, a separation chamber, and collection systems. Particles of unburned carbon and fly ash can be imparted positive and negative surface charges, respectively, with a copper tribocharger due to differences in the work function values of the particles and the tribocharger, and can be separated by passing them through an external electric field. Results showed that fly ash recovery was strongly dependent on the electric field strength and the particle size. 70wt% of fly ash containing 6.5wt% of carbon contents could be recovered at carbon contents below 3%. The triboelectrostatic separation system showed a potential to be an effective method for removing unburned carbon from coal fly ash.

• 한국의류학회지
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• 제26권1호
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• pp.160-167
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• 2002

Stretch fabrics are wide-spread for high performance clothing use with requirements of fitness and adaptability to human's movement. A newly developed 100% PET high stretch fabric has excellent properties with respect to stretch, softness, bulkiness, and apparent volume compared to PET filament fabrics. The 100% PET high stretch fabric shows advantages of a dimensional stability, dye and agent adaptability in dying and finishing process, a property of stretch recovery after washing and lower production cost than that of spandex fabric. KES-FB was used to measure mechanical properties to various directions of the fabric. This study centered on whether the 100% PET high stretch fabric is suitable to quality and shape retention of fabric by testing several properties including tensile, compression, shear, bending and surface characteristic to various measuring directions. Tensile linearity showed maximum value at $0^{\circ}$ in plain and $90^{\circ}$ in twill. Shear Stiffness of plain and twill showed maximum value equally at $45^{\circ}\;and\;135^{\circ}$. Bending rigidity showed maximum value at $0^{\circ}$ in plain and $45^{\circ}$ twill. Mean deviation of MIU showed maximum value at $0^{\circ}\;and\;90^{\circ}$ in plain and $135^{\circ}$ in twill.

• 한국항공운항학회지
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• 제26권3호
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• pp.9-22
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• 2018

Korea meteorological administration(KMA) has started to levy air meteorological service charge on both national and foreign carriers since 2005. The charge has grown on 2010 and 2014 twice. However, KMA has still kept asking airlines to agree with another increase in the charge due to the low cost of goods recovery ratio of 7%. The air meteorological charge has changed from 2,210 KRW at the beginning to 11,400 KRW as of June 2018. According to ARIMA intervention time series analysis, it was proven national carriers would make a payment of 831 million KRW 2018 and 1,024 million KRW 2019, showing 186.2% and 123.2% increase compared to last year respectively. The total amount of charge for both national LCC and foreign airlines was aggregated up to 1,952 million KRW 2019, 227% bigger than the charge paid at 2017. Considering the 50% increase of consumer price index last decade, the increased charge would impair the global competitiveness of national carriers. It could be suggested that current air meteorological charge scheme be improved to apply overseas trend and for national carriers to have a competitive advantage in global aviation market.

• 한국항행학회논문지
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• 제13권5호
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• pp.699-704
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• 2009

지구 온난화 및 환경 파괴 등으로 인해 재난 발생 빈도가 높아지고, 피해 또한 가속화됨에 따라 실시간 환경 변화의 인식을 통한 재난 안전에 대한 요구가 증가하고 있다. 특히 국지적 기후 변화로 인한 피해가 높게 발생하고 있는 실정이다. 이에 지역적 재난 안전에 대한 대처 방안이 요구된다. 본 논문에서는 동해안의 해상 기상 악화로 사고발생 우려가 높아지고 있는 해안 방파제를 대상으로 무선 센서 기술을 통합하는 재해 안전 모니터링 시스템을 제시하고자 한다. 제시된 재난 안전 시스템은 실시간 원격지 상황 정보와 예측시스템을 통해 발생 가능한 위기상황을 파악하고 재해예방 및 피해를 감소시키는데 많은 도움을 제공할 수 있을 것이다.

• 통상정보연구
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• 제12권3호
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• pp.79-98
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• 2010

The National Conference of Commissioners on Uniform State Laws promulgated the Uniform Computer Information Transactions Act (UCITA) in 1999. In 2000 and 2002, this Act was also Amended. UCITA provides a comprehensive set of rules for licensing computer information, whether computer software or other clearly identified forms of computer information. Computerized databases and computerized music are other examples of computer information that would be subject to UCITA. It would also govern access contracts to sites containing computer information, whether on or off the Internet. UCITA would not govern contracts, even though they may be licensing contracts, for the traditional distribution of movies, books, periodicals, newspapers, or the like. Part 8 of UCITA provides a remedy structure somewhat modeled on that of Article 2 but adapted in significant respects to the different context of a computer information transaction. For example, 808 of UCITA recognizes the focus in a license context for a licensor's remedy should properly be on recovery for benefit conferred or for lost profit, rather than on damage measurement by a substitute transaction, where the license is non-exclusive so additional transactions are permitted and there is very little cost in reproduction of the information and its redistribution. Section 816 of UCITA also contains very important limitations on the generally recognized common law right of self-help as applicable in the electronic context.

• International Journal of Fluid Machinery and Systems
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• 제9권3호
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• pp.256-264
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• 2016

To meet the demand of higher handling capacity, a mixed-flow submersible deep well pump was designed and tested. The main hydraulic components are made of plastics, which is free of erosion, light-weight, and environment-friendly. To simplify plastic molding process, and to improve productivity, an axial-radial guide vane was proposed. To clarify its effect on the performance, a radial guide vane and a space guide vane are developed as well. By comparison, the efficiency of the pump equipped with the axial-radial guide vane is higher than the radial guide vane and is lower than the space guide vane, and its high efficiency range is wide. The static pressure recovery of the axial guide vane is a bit lower than the space guide vane, but it is much larger than the radial guide vane. Taking the cost and molding complexity into consideration, the axial-radial guide vane is much economic, promoting its popularity for the moderate and high specific speed submersible deep well pumps.

• 한국수소및신에너지학회논문집
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• 제26권1호
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• pp.45-53
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• 2015

The objective of this study is to develop a gas pro-treatment system for DME synthesis, wherein this system separates $CO_2$ from Flaring gas as Membrane, in order to save raw material ($CH_4$) cost of DME. In this study, hollow fiber membrane is developed, which is able to separate high-pressure gas, supported by polysulfone and coated with amorphous fluorinated polymer. Throughout the evaluation of the membrane's separation characteristics, the membrane is applied to this system. The membrane is designed by 2 stages for over 90% removal rate of $CO_2$ and over 90% recovery rate of $CH_4$. The bench scale of pro-treatment system is developed as $25Nm^3/hr$.

• 항공우주산업기술동향
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• 제8권1호
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• pp.12-22
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• 2010

금융위기로 불거진 불경기와 불확실성에서 기인한 국제 유가의 변동은 세계 항공기 시장에도 심각한 영향을 끼쳤다. 항공 수요의 급감과 운영비용의 증가를 가져왔으며, 이에 따라 항공기 수요의 특성과 양에 있어서도 변화가 발생하였다. 2000년대 중반의 경기 회복기조 속에서 항공기 주문과 인도가 급증하였으나, 2009년에는 주문량이 급감하였으며, 신형 항공기의 인도와 항공수요 급감에 따라 중고항공기 및 임대 시장 그리고 MRO 시장도 축소되었다. 이렇게 위축된 항공기 수요는 2009년 하반기 세계 항공물류 및 승객 수송의 회복으로 다시 반등을 보이고 있으며, 향후 수요는 단일 통로기가 광동체기의 수요를 인도할 것으로 보인다. 현재, 시장의 반등이 단기적으로 끝날지 지속적으로 이어질 지에 대해서 확답을 내릴 수는 없으나, 장기적으로는 지속적인 항공기 수요의 증가가 이어질 것으로 예상되며, 이러한 수요는 아시아, 아프리카 등의 신흥시장의 성장에 힘입을 것으로 기대된다.

• 대한전자공학회논문지TC
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• 제40권8호
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• pp.318-330
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• 2003

The advantages of "VPN over Internet" are cost-effectiveness and flexibility However, the disadvantages are the lack of sufficient QoS mechanism and transmission capacity for high bandwidth service. Given this increasing demand for high bandwidth Internet and QoS assurances in "PN over Internet", IP/GMPLS based control plane combined with a high bandwidth capacity of DWDM optical network is seen as a very favorable approach for the realization of future "OVPN over IP/GMPLS over DWDM" Within OVPN for providing QoS guaranteed multimedia service over the NGOI(Next Generation Optical Internet) based on the "IP/GMPLS over DWDM" concept, differentiated QoS framework is one of the key issues to implement OVPN over DWDM-based NGOI. Keeping in mind that IETF(Internet Engineering Task Force) and ITU-T(International Telecommunication Union) are standardizing IP/GMPLS over DWDM protocol framework as a solution for the NGOI, in this paper, we suggest Optical-LSP establishment and QoS maintenance scheme based on DOQS(Differentiated Optical QoS Service) classes, which are the key issue of DOQS protocol framework for assuring end-to-end QoS in "OVPN over IP/GMPLS over DWDM".