• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.683-684
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• 2012

• Aerospace Engineering and Technology
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• v.3 no.2
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• pp.124-132
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• 2004

This paper deals with the static and dynamic analysis of the housing and PCB of TCU(Thruster Control Unit) for KSLV-I(Korea Space Launch Vehicle-I). TCU should pass the environment test simulating the flight environment of KSLV-I. The most important tests are the vibration and the shock tests. In this research, we proposed a design standard about the vibration and the shock environment and then verified TCU housing and PCB design met the standard. Based on the analytical results, the TCU housing was redesigned to meet the design standard. The new design is supposed to pass the environment test.

• Aerospace Engineering and Technology
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• v.4 no.2
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• pp.203-208
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• 2005

Electronic components for space launch vehicles are exposed to a severe vibrational environment at launch and flight. The structural reliability of each component can be verified using mathematical approaches. In order to verify the structural reliability, an important parameter is the natural frequency of PCB(Printed Circuit Board) assembly mounted electronic components on and housing mounted PCB assembly in. In this paper, in order to find natural frequencies of PCB assemblies and the housing of hydrazine TCU(Thruster Control Unit), FEM(Finite Element Method) is adapted. The analytical result of FEM is verified by experimental method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2015-2022
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• 2012

This paper is about the analysis and design of avionics equipment's housing and PCB(Printed Circuit Board) such as air data computer. Avionics equipment's structural design as well as electrical properties is very critical and should be proved from design phase by analysis method. First, analyze the static load and vibration requirement for the installed equipment, and then proved it satisfy with its requirement using the computational structural analysis. Commercial tools were used for computation and the rib design of housing was verified and the placement of electrical component was proposed using the PCB's local displacement information.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.7
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• pp.636-645
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• 2015

In this paper, unusual harmonics noise problem of digital electronic products in mass production was introduced and a practical solution was proposed. Generally, 5th or higher harmonics noise level has been ignored in circuit designs because over 5th harmonics noise decreases by 40 (dB/decade). Through some measurements, it is confirmed that over 10th harmonics noise can propagate and radiate in case of a certain PCB or housing conditions. We propose a capacitively loaded micro-strip low pass filter for commercial products having spatial design constraints and measured the effectiveness. The proposed structure can solve both of the continual increment of harmonics noise level and the spatial design constraint of commercial products. We expect the proposed method be effectively used for various digital electronic products.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.201.2-201.2
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• 2012

위성용 초고주파신호분배기(이하, RFDU)는 위성에 장착된 두 개의 안테나와 두 개의 송수신기 사이에 위치하게 되며, 지상으로부터 송신된 제어신호와 위성의 상태 정보 신호를 전달/분배하는 RF 신호 경로를 제공하게 된다. 기존의 위성용 RFDU의 구조는 cavity 형태의 필터로 구성된 diplexer와 hybrid RF coupler 및 저역통과필터 들이 서로 SMA 케이블로 연결되어 있는 부피가 큰 구조이다. 또한 차세대 위용용 부품들은 위성을 경제성 등을 고려하여 소형/경량화 개발이 요구되고 있으며, 특히 위성용 S 대역 TC/TM 통신링크에서 RFDU와 트랜스폰더는 소형 경량화를 위해 단일 unit으로 개발되고 있다. 이에 따라 기존의 RFDU 또한 전기적 성능을 유지하면서 소형/경량화 개량 개발이 필요하다. 본 연구에서는 기존 RFDU의 소형 경량화를 위해 PCB와 housing을 이용하여 cavity 필터특성을 갖는 diplxer를 개발/구현 하였으며, PCB 페턴을 통한 내부 인터페이스용 SMA 케이블 제거 등을 적용하였다. 또한 microstrip 타입의 저역통과필터을 적용하여 소형 경량화를 이루었으며, 새로이 개발된 소형/경량의 RFDU는 전기적으로 기존의 그것과 유사하거나 동등한 특성을 갖는 것을 확인하였으며, 기존 RFDU 대비 무게 및 부피는 60 % 이상 감소하여 소형/경량화 개발을 성공하였다. 본 개발 결과물은 향후 차세대 위성용 RFDU 개발을 위한 기초 자료로 활용할 것이다.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.7
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• pp.377-386
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• 2016

The purposes of this research are to examine soil pollution in the nation and to explore the contaminated soil management of the public housing agency in public land for residential development. In so doing, the primary and secondary data were utilized, the former made use of the public data annually released by the Korea Ministry of Environment, and the latter relied on a self-administerd questionnaire survey conducted in the staff of the public housing agency, particularly those in charge of soil contamination in large-scale land, housing and urban development projects. The findings reveal that the national concentrations of 21 inorganic and organic soil contaminants (e.g., Cd, Cu, As, Hg, Pb, Cr, Zn, Ni, F, P, PCB, CN, Phenol, BTEX, TPH, TCE, PCE, Benzo(a)pyrene, and pH) in the land were extracted to be well below the risk level designated by the statutory guidance while industrial areas had them at a relatively modest level. In addition, the survey results indicate that the public housing agency didn't establish specific and clear guidelines for soil pollution and its remediation in the residential land development, so that contaminated sites have been primarily remediated by outsourcing companies. As the unexpected occurrence of contaminated sites causes the incurring expenses added to total project budget, the provision of both professional training and on-site manuals with the sufficient information on techniques and methods of soil contamination is critical to promptly and systematically deal with soil pollution.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.10
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• pp.820-826
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• 2013

In this paper, a compact and wideband CLAS(Conformal Load bearing Antenna Structure) was studied using smart skin technique. In order to satisfy the electrical performance of the CLAS antenna, the proposed CLAS antenna is composed of conductive mesh, face-sheet, radiator, honeycomb, housing. Especially, radiator is composed of composite magneto-dielectric material and radiating element etched on the PCB (Printed Circuit Board). The radiating element is inserted into the composite magneto-dielectric material and has sloted Folded LP(Log Periodic) structure. By fabricated composite magneto-dielectric, the resonance frequency is decreased and the impedance matching characteristics is improved. We verified that the antenna has wideband characteristics and compact size using the antenna test results.

• Journal of the Korean Society of Safety
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• v.28 no.2
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• pp.21-25
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• 2013

The purpose of this study is to provide basic data for the safety assessment of a water purifier when water leaks due to inappropriate maintenance and the examination of the cause of accidents related to the leak. Due to its inspection and management by non-specialists, if a leak occurs in a water purifier with the water level controller being inclined, it may result in the failure of the compressor, power supply line, PCB, etc. The analysis of the thermal diffusion pattern of water purifier compressors using a thermal image camera shows that its maximum temperature was approximately $80^{\circ}C$. In addition, its operating current was a maximum of 13 A and the system's operating current was approximately 1.7 A after the compressor was charged. It was found that the housing type power cable cover of the compressor had the effect of preventing electric shock but has poor flame resistance. Furthermore, the performance of the overload protector, PTC relays, etc., was excellent but they have potential for problems as metallic terminals were exposed, resulting in the potential of a safety related accident. The terminals and their surface damaged by the tracking showed a trace of carbonization and the resistance between terminals was measured to be approximately $8{\Omega}$. In addition, while the tracking was proceeding, the fuse and circuit breaker installed for system protection did not operate.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.10
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• pp.1997-2007
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• 2002

Composite air spindles are appropriate for the high-speed and the high-precision machining as small hole drilling of printed circuit board (PCB) or wafer cutting for manufacturing semiconductors because of the low rotational inertia, the high damping ratio and the high fundamental natural frequency of composite shaft. The axial load and stiffness of composite air spindles fur drilling operation are determined by the thrust ben ring composed of the air supply part mounted on the housing and the rotating part mounted on the rotating shaft. At high-speed rotation, the rotating part of the thrust bearing should be designed considering the stresses induced by centrifugal force as well as the axial stiffness and the natural frequency of the rotating shaft to void the shaft from failure due to the centrifugal force and resonant vibration. In this work, the air supply part of the thrust bearing was designed considering the bending stiffness of the bearing and the applied load. The rotating part of the thrust bearing was designed through finite element analysis considering the cutting forces during manufacturing as well as the static and dynamic characteristics under both the axial and con trifugal forces during high-speed rotation.