• Tribology and Lubricants
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• 제40권1호
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• pp.24-27
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• 2024

A monotype valve body for a dual clutch transmission has the potential to reduce costs, weight, and manufacturing time by modularizing various parts, including those of existing solenoid packs and valve bodies, into one through the application of super-precision die casting technology. However, this approach may lead to challenges such as reduced rigidity and increased interference due to modularization and compactness, impacting both product performance due to the reduced weight as well as durability and reliability. Unlike existing products, this approach requires a high-precision thin-wall block to avoid more complicated flow line formation, interference between flow lines, and leaks, as well as a strict quality requirement standard and precise inspections including detection of internal defects. To conduct precise inspections, we built an equivalent model corresponding to a driving distance of 300,000 km. Testing involved simulating actual road loads using a real vehicle and a chassis dynamometer in the FTP-75 mode (EPA Federal Test Procedure). The aim of the study was to establish a vehicle load-based part durability model for manufacturing a mono-type valve body and to develop fundamental technology for part weight reduction through preliminary design by introducing analytical weight reduction technology based on the derived results.

• 조명전기설비학회논문지
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• 제28권1호
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• pp.16-28
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• 2014

This paper presents a novel high-power-factor circuit topology of AC to AC current-fed type high frequency resonant inverter which includes the function of power factor correction(PFC) in the proposed inverter to operate the AC input block with high power factor. The proposed circuit topology of AC to AC current fed type high resonant inverter removes DC link electrolytic capacitor and has also the one of power factor correction(PFC) in the inverter circuit without an additional PFC circuit since the input current by constituting it in parallel as an unit inverter, which assumes the class-E high frequency resonant inverter of conventional current-fed type, flows in the form of the resultant current flowing through each constant current reactor($L_{d1}$, $L_{d2}$). The circuit analysis of proposed inverter is generally described by adopting the normalized parameters and the evaluation of its operating characteristics are conducted by using the parameters such as the ratio of switching and resonant frequency(${\mu}$), coupling coefficient(k) and so on. An example of procedure for circuit design based on the characteristic values obtained from the theoretical analysis is presented. To confirm the validity of the theoretical analysis, the experimental results are also presented. In the future, the proposed inverter shows it can be practically used as power supply system for induction heating application, DC-DC converter etc.

• 대한치과보철학회지
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• 제46권3호
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• pp.261-268
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• 2008

STATEMENT OF PROBLEM: Detachment of the magnetic assembly from the denture base has been a problem in magnetic overdenture patients. PURPOSE: The objectives of this study were to compare the dislodging force by the fixing materials and the designs of the magnetic assembly, and to compare the effect between the fixing materials and the designs of the magnetic assembly. MATERIAL AND METHODS: Two fixing materials, Jet denture repair $acrylic^{(R)}$ and Super-$Bond^{(R)}$ C&$B^{(R)}$ and two types of magnetic assembly designed with or without wing were used. Each magnetic assembly was fixed in the chamber of the denture base resin block ($Lucitone^{(R)}$199) with each fixing material respectively. These specimens were thermocycled 2,000 cycles in the water held at $4^{\circ}C$ and $60^{\circ}C$ with a dwell time of 1 min each time. Each specimen was seated in a testing jig and then a push-out test was performed with a universal testing machine at a cross head speed of 0.5 mm/min to measure the maximum dislodging forces. RESULTS: Comparing the fixing materials, Super-Bond C&$B^{(R)}$ showed superior dislodging force than Jet denture repair $acrylic^{(R)}$. Comparing the design of the magnetic assemblies, the wing design magnetic assembly showed better dislodging force. Combination of the Super-Bond C&$B^{(R)}$ as a fixing material and wing design magnetic assembly revealed a greatest dislodging force. The kind of fixing material was more influential than the type of magnetic assembly. CONCLUSION: The dislodging force of Super-Bond C&$B^{(R)}$ was significantly higher than Jet denture repair $acrylic^{(R)}$. And the dislodging force of magnetic assembly which have wing design was significantly higher than magnetic assembly which have no wing design.

• Nuclear Engineering and Technology
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• 제39권1호
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• pp.9-20
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• 2007

Design study on the Gas Turbine High Temperature Reactor 300-Cogeneration (GTHTR300C) aiming at producing both electricity by a gas turbine and hydrogen by a thermochemical water splitting method (IS process method) has been conducted. It is expected to be one of the most attractive systems to provide hydrogen for fuel cell vehicles after 2030. The GTHTR300C employs a block type Very High Temperature Reactor (VHTR) with thermal power of 600MW and outlet coolant temperature of $950^{\circ}C$. The intermediate heat exchanger (IHX) and the gas turbine are arranged in series in the primary circuit. The IHX transfers the heat of 170MW to the secondary system used for hydrogen production. The balance of the reactor thermal power is used for electricity generation. The GTHTR300C is designed based on the existing technologies of the High Temperature Engineering Test Reactor (HTTR) and helium turbine power conversion and on the technologies whose development have been well under way for IS hydrogen production process so as to minimize cost and risk of deployment. This paper describes the original design features focusing on the plant layout and plant cycle of the GTHTR300C together with present development status of the GTHTR300, IHX, etc. Also, the advantage of the GTHTR300C is presented.

• 한국철도학회논문집
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• 제19권6호
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• pp.826-832
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• 2016

트램 건설시 LID 기법 적용에 따른 환경편익 증대 방안으로 경제성 평가에서 온실가스 저감에 따른 환경편익을 계량화하였다. 또한 LID 기법 중 침투형 투수블록 적용에 따른 도시물순환 효과를 정책성 분석시 사업특수 평가항목으로 선택할 수 있는지 여부에 대한 가능성에 대해서도 검토하였다. 투수잔디블록의 사용에 따른 콘크리트 궤도 대비 탄소배출 비율은 잔디 피복율(100%, 50% 화강석, 50% HDPE)에 따라 각각 -184.7%, -127.3%, -116.3%로 산출되었으며, 투수블록의 경우에는 화강석 및 HDPE 각각 30.1%, 52.5%로 산출되었다. 침투형 투수블록을 적용할 경우 강우강도 90mm/hr까지 저수가 가능한 것으로 나타났으며(저수율 94.3%), 도시물순환 시스템으로써 효과가 있을 것으로 판단된다. 결과적으로 트램건설시 LID 기법 적용으로 환경편익의 증대가 기대되며 추후 AHP 분석에서 정책적 요소로도 다루어질 필요가 있다.

• 한국정보과학회논문지:시스템및이론
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• 제32권2호
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• pp.75-84
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• 2005

이 연구는 공간적/시간적 지역성의 효과론 이용하기 위하여 SRAM 버퍼를 사용하는 고성능 NAND-Type 플래쉬 메모리 패키지의 설계에 관한 것이다. 제안된 SRAM 버퍼를 내장한 새로운 NAND형 플래쉬 메모리 패키지 구조는 크게 세 부분으로 구성되어 있다. 즉, 작은 블록 크기의 완전 연관 희생 버퍼(victim buffer)와 큰 블록 크기를 지원하는 완전 연관 공간 버퍼(spatial buffer), 그리고 동적 페칭 유닛(dynamic fetching unit)으로 구성되어 있다. 제안하는 새로운 NAND 형 플래쉬 메모리 패키지는 기존의 NAND형 플래쉬 메모리 구조와 비교할 때 매우 뛰어난 성능 향상 및 저 전력 소비를 이끌어낼 수 있다. 시뮬레이션 결과에 따르면 제안된 NAND 플래쉬 메모리 패키지는 기존의 NAND 플래쉬 메모리와 비교하여 접근 실패율에서는 70%, 평균 메모리 접근 시간에서는 67%의 감소 효과를 보여준다. 더욱이 주어진 크기(e.g., 3KB)의 SRAM 버퍼를 이용한 제안된 패키지는 여덟 배 크기의 직접 사상 버퍼(e.g., 32KB)를 이용한 패키지 및 두 배 크기의 완전 연관 버퍼(e.g., 8KB)를 이용한 패키지보다도 평균 접근 실패율 및 평균 메모리 접근 시간에서 더욱 우수한 성능 향상을 이끌어낼 수 있다.

• 한국정보통신학회논문지
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• 제11권10호
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• pp.1916-1923
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• 2007

대역통과용 표면 탄성파 필터 제작하기 위하여 Langasite 기판위에 빗살무의 변환기를 형성 시켜 모의실험을 수행하였으며, 전극재료로는 Al-Cu를 사용하였다. 모의실험을 바탕으로 입력단에는 IDT를 직렬형태로 연결시킨 block 형태로 하중을 가하는 전극 방법을 쓰고 출력 단은 withdrawal 형태로 하중을 가하는 방법을 써서 제작하였다. 이를 바탕으로 광대역의 SAW 필터 전극 설계 방식에 대한 적절한 위상조건도 얻고자 시도하였다. Langasite 기판위에 형성시킨 입출력 빗살무의 변환기 전극 수는 50쌍, 두께는 $5000\;{\AA}$으로 하였으며, 반사기 폭은 $3.6{\mu}m$으로 하였다. 그리고 hot전극과 반사기사이의 거리는 각각 $2.0{\mu}m\;2.4{\mu}m$로 제작하였고, hot전극에서부터 접지전극까지 간격은 $1.5{\mu}m$로 하였으며 전극 모양은 좌우 동일한 형상을 채택하였다. 제작한 필터의 주파수 특성은 중심주파수가 대략 190MHz정도, 대역폭은 7.8MHz 이하로 측정되었으며, matching 후 return-loss는 -18dB 이하이고, 리플 특성은 3dB 이하이며, 반사에 의한 잔향은 -25dB 이하로 측정되었다.

• Human Ecology Research
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• 제54권1호
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• pp.13-26
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• 2016

The purpose of this paper is to investigate the rationale behind the transformation process of unique shophouse spatial organization in Phnom Penh. We selected 20 representative shophouses located in the Chinese district of Phnom Penh according to construction period. A qualitative study methodology was applied and field surveys were conducted that included interviews with residents, photographs, sketches, measurements, collecting historic photos, and cataloging maps. Selected cases were analyzed in terms of: basic house data, urban block analysis, and unit analysis. Cases were then classified into two types: private courtyard shophouse (PCS) and shared courtyard shophouse (SCS). PCS refers to shophouse typology that maintains most of the characteristics of early shophouses while being transformed into a modern multi-story apartment within a limited one bay plot. However, SCS refers to shophouses adapted from the indigenous forms of PCS that evolved into a multi-storey and multi-family housing typology that includes features that might have been adapted from Western apartment buildings such as sharing a big courtyard, staircase and corridors. We conclude that shophouses in Phnom Penh have positively adopted a Western building typology, adapted it to local traditions, and finally formulated a new building type that represent indicators of a modernization process gradually accepted by society.

• 한국자동차공학회논문집
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• 제9권1호
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• pp.181-188
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• 2001

The evaluation of the noise for the an existing engine was carried out to improve the current noise level. The applied techniques were 1m air-borne noise, combustion noise analysis, torsional analysis at the front pulley and sound pressure intensity. In addition, the evaluation of the possibility to the noise reduction by means of wrapping the parts was performed to propose the detailed information in engine design. In view of the obtained results, the following countermeasures were recommended to reduce the current noise level through the above methods. Furthermore, in order to assess the influence of combustion noise on the overall engine noise, the noise test was also performed by the change of intake air temperature up to 5$0^{\circ}C$ in steps of 1$0^{\circ}C$. Finally, the fixed design specifications to reduce the engine noise will be decided in consideration of the test data for proto type engine.

• 한국항공우주학회지
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• 제32권8호
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• pp.129-137
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• 2004

본 연구에서 시험부 크기 $30mm{\times}35.6mm$, Run Time 20초인 소형-저가의 초음속 풍동을 개발하였다. 개발원 교육용 초음속 풍동은 단속적 불어내기식형이며 , 노즐 블록 교체형으로 설계되었다. 본 연구를 통하여 초음속 풍동에 사용되는 대형-고가의 기계장비를 기존 소형의 상용 제품으로 대체하여 제작 단가를 낮추었다. 그리고 초음속 풍동의 핵심 기술인 노즐 설계를 비롯한 전체적인 초음속 풍동 설계 기술을 확보하였다. 풍동 시험부에서의 초음속 유동장 형성 및 유동 안정성에 대한 성능검증 실험을 수행하였다.