• Membrane Journal
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• v.9 no.2
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• pp.89-96
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• 1999

국내 K-그룹 연구소에서 제조한 폴리설폰 중공사막의 산소/질소 혼합물에 대한 압력, stage , cut , 공급기체 혼합물의 조성에 따른 분리성능을 조사하였다. 본 실험의 압력범위와 온도 3$0^{\circ}C$에서의 이상분리인자 (O2/N2)는 5.7이었으며, 유입기체 혼합물의 21mole % 산소농도가 약 50 mole%로 농축되었다. 저압측과 고압측의 압력비는 산소농축에 미치는 영향이 적었으며 이상분리인자의 영향은 매우 컸다. 그러나, 이상분리인자가 증가함에 따라 이상분리인자의 영향은 둔화되었다. 따라서, 이상분리인자가 큰 신소재 개발과 더불어 공정변수의 최적화가 필요하다. 수학적 모델링에 의한 예측치와 실험치가 잘 맞았다.

• Membrane Journal
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• v.8 no.2
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• pp.59-68
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• 1998

고정발생원으로 부터 배출되고 있는 이산화탄소를 분리하여 회수 및 재이용하는 기술개발이 에너지 보전 측면에서 뿐만 아니라 환경오염 문제 등을 해결할 수 있는 중요한 과제이다. 특히 내열성, 내식성 및 기계적 강도가 뛰어난 세라믹의 특성을 이용한 기체분리막을 응용한다면 고온으로부터 저온까지의 폭넓은 온도, 압력, 가스조성의 배기가스로부터 이산화탄소를 분리하는 것이 가능해 진다. 따라서 본 총설에서는 현재 일본에서 국책과제로 진행되고 있는 이산화탄소의 고온분리에 대한 연구개발(이하, '$CO_2$ 프로젝트'로 약칭) 현황을 소개하고자 한다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1993.10a
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• pp.191-196
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• 1993

본 연구에서는 이러한 방진궤도의 성능을 파악하고 또 적절한 방진궤도의 설계를 위하여 먼저 모형화하는 방법을 제시하였다. 이를 위해서는 궤도를 구성하는 방진요소의 특성을 결정하는 것이 필수적이므로 현재 사용되고 있 는 점탄성 방진재에 대하여 주파수, 온도, 초기 변형률, 동적변형률등 여러가 지 인자에 대한 물성치를 구하였으며, 이를 이용하여 궤도계의 진동전달 특 성을 파악하고 고찰하였다.

• Membrane Journal
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• v.6 no.4
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• pp.236-241
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• 1996

We prepared temperature-sensitive polyurethane and its water permeation characteristics for possible uses as drug delivery systems. Mechanical properties and Tg of polyurethane depend on the molecular weight of polyol and the amount of hard segment. We confirmed the increase of permeability with temperature. This fact indicates the future use of the present material in drug delivery systems.

• Journal of the Korea Society of Computer and Information
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• v.16 no.6
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• pp.1-10
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• 2011

In designing multi-core processors, interconnection delay is one of the major constraints in performance improvement. To solve this problem, the 3-dimensional integration technology has been adopted in designing multi-core processors. The 3D multi-core architecture can reduce the physical wire length by stacking cores vertically, leading to reduced interconnection delay and reduced power consumption. However, the power density of 3D multi-core architecture is increased significantly compared to the traditional 2D multi-core architecture, resulting in the increased temperature of the processor. In this paper, the floorplan methods which change the forms of vertical placement of the core and the level-2 cache are analyzed to solve the thermal problems in 3D multi-core processors. According to the experimental results, it is an effective way to reduce the temperature in the processor that the core and the level-2 cache are stacked adjacently. Compared to the floorplan where cores are stacked adjacently to each other, the floorplan where the core is stacked adjacently to the level-2 cache can reduce the temperature by 22% in the case of 4-layers, and by 13% in the case of 2-layers.

• Composites Research
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• v.35 no.3
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• pp.201-215
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• 2022

This paper presents the development of thin and lightweight ultra-high temperature radar-absorbing ceramic composites composed of an aluminosilicate ceramic matrix-based geopolymer reinforced ceramic fiber and sendust magnetic nanoparticles in X-band frequency range (8.2~12.4 GHz). The dielectric properties with regard to complex permittivity of ceramic/sendust-aluminosilicate composites were proportional to the size of sendust magnetic nanoparticle with high magnetic characteristic properties as flake shape and its concentrations in the target frequency range. The characteristic microstructures, element composition, phase identification, and thermal stability were examined by SEM, EDS, VSM and TGA, respectively. The fabricated total thicknesses of the proposed single slab ultra-high temperature radar absorber correspond to 1.585 mm, respectively, exhibiting their excellent EM absorption performance. The behavior of ultra-high temperature EM wave absorption properties was verified to the developed free-space measurement system linked with high temperature furnace for X-band from 25℃ to 1,000℃.

• Journal of the Korean Institute of Gas
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• v.14 no.2
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• pp.40-46
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• 2010

In this study, the integrated control and safety management system for a super-large LNG membrane storage tank has been presented based on the investigation and analysis of measuring equipments and safety analysis system for a conventional LNG membrane storage tank. The integrated control and safety management system, which may increase a safety and efficiency of a super-large LNG membrane storage tank, added additional pressure gauges and new displacement/force sensors at the steel anchor between an inner tank and a prestressed concrete structure. The displacement and force sensors may provide clues of a membrane panel failure and a LNG leakage from the inner tank. The conventional leak sensor may not provide proper information on the membrane panel fracture even though LNG is leaked until the leak detector, which is placed at the insulation area behind an inner tank, send a warning signal. Thus, the new integrated control and safety management system is to collect and analyze the temperature, pressure, displacement, force and LNG density, which are related to the tank system safety and leakage control from the inner tank. The digital data are also measured from measurement systems such as displacement and force of a membrane panel safety, LNG level and density, cool-down process, leakage, and pressure controls.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.123-123
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• 2018

최근 웨어러블 디바이스에 연구가 집중되면서 투명하고 유연한 마이크로 히터의 필요성이 증가되고 있다. 그럼에도 불구하고, 기존의 사용되는 마이크로 히터들은 딱딱하고 불투명하다. 게다가, 기존의 금속성의 마이크로 히터들의 경우 저항이 너무 작아 웨어러블 디바이스에 사용되는 에너지 하베스터로 구동되기에 효율이 떨어지는 경향이 있다. 이 논문에서 우리는 CVD 방식으로 성장된 그래핀으로 열 발생 라인을 패시베이션 레이어로 h-BN을 이용하여 투명하고 유연한 마이크로 히터를 제작하였다. 제작한 마이크로 히터는 균일한 온도 분포와 200도까지의 온도 상승에 걸리는 시간이 4초 정도로 굉장히 좋은 성능을 보유하고 있다. 또한 소비 전력은 39mW 이하로 효율적이다. 또한 기존의 메탈릭 히터에 비해 저항이 굉장히 높기 때문에 웨어러블 에너지 하베스터로 작동하기 적합하다. 또한 미래의 휴대용/웨어러블 개인 전자기기와 무선 헬스케어 제품, 휴대용 환경 센서에도 적용될 것으로 기대한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.4
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• pp.35-41
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• 2020

The small tracking radar is a very important component of the wire harness design because the components are organically connected. In addition, the cable connected to the signal processing unit and the servo unit having a large number of digital signals should be prepared to prevent the CPU of the signal processing unit from malfunctioning due to electromagnetic noise. Cables for signal transmission in the ◯◯ GHz band must reflect the design of temperature, vibration, and shock. To design a wire harness in a small space, the size of the connector must be minimized. The issues to be considered are described and the design plan is presented.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.2
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• pp.169-177
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• 2016

Sliding slab track system, which consists of low friction sliding layer between track slab and bridge deck, is recently devised to reduce track-bridge interaction effect of continuously welded rail(CWR) without applying special devices such as rail expansion joint(REJ). In this study, a series of track-bridge interaction analyses of a long-span bridge with sliding slab track and REJ are performed respectively and the results are compared. The bridge model includes PSC box girder bridge with 9 continuous spans, and steel-concrete composite girder bridge with 2 continuous spans. The total length of the bridge model is 1,205m, and the maximum spacing between the two fixed supports is 825m. Analyses results showed that the sliding slab track system is highly effective on interaction reduction since lower rail additional axial stress is resulted than REJ application. Additionally, horizontal reaction forces in fixed supports were also reduced compared to the results of REJ application. However, higher slab axial forces were developed in the sliding slab track due to the temperature load. Therefore, track slab section of the sliding slab track system should be carefully designed against slab axial forces.