• Tribology and Lubricants
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• 제2권1호
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• pp.61-68
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• 1986

Effects of the ram-pressure on the THD-performance of pivoted pad thrust bearings are investigated experimentally. A sector-shaped tilting pad thrust bearing and a rotating disk are used. Temperature distribution on the disk surface as well as on the pad surface, distribution of the pressure generated within the fluid film, and the film thickness are measured continuously in the circumferential direction after thermal equilibrium is established. The ram-pressure is proportional to the mean pressure of oil film and to the rotational speed of the disk and affects the maximum pressure and the pressure distribution. The temperature rise on the mating surface of the disc and the pad, contacting with the oil film, is proportional to to the bearing load and the disk speed. The ram-pressure and the temperature rise on the disk surface are dominant factors that affect the THD-performance of pivoted pad thrust bearings.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1995년도 춘계공동학술대회논문집; 전남대학교; 28-29 Apr. 1995
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• pp.111-120
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• 1995

통합생산시스템에서의 고장, 정비 및 가용 도는 매우 중요한 역할을 한다. 시스템 설계시의 RAM 파라메터의 결정은 시스템의 성능과 소요비용 및 구성(System Configuration)등에 크게 영향을 미친다. 이러한 시스템관련 요소의 숫자가 많거나 불확실할 경우는 시스템의 성능예측이 매우 복잡하게 된다. 이러한 시스템의 성능(performance) 평가를 위하여 발견적 방법인 GMDH(Group Method Data Handlinng) Type Modeling 방법을 이용하여 FMS의 성능 평가를 시도하였다. RAM 및 기계작업시간의 Data로부터 시스템성능의 척도로서 단위 사이클 기간동안의 생산률, 시스템내의 총 흐름시간, 각 작업장이 기계의 RAM 및 LCC등을 고려하였다. GMDH 알고리즘의 계산을 위한 프로그램을 개발하고, 이를 L형 Bracket제조시스템의 성능 예측에 시험 적용하였다. 본 Modeling에 의한 시스템의 성능예측 방법은 입출력 자료의 처리과정을 개선할 경우 FMS계획및 운영 단계에서 성능평가에 매우 유용하게 활용될수 있을 것으로 본다.

• E2M - 전기 전자와 첨단 소재
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• 제6권6호
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• pp.554-563
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• 1993

본 연구는 복소유전률 측정장치의 실현을 목표로 한 것이다. 본 장치는 인터페이스 유니트, 외부 RAM, 프로그래머블 카운터, D/A 콘버터, 측정회로, S&H 회로, A/D콘버터 및 기타 제어회로로 구성하였다. 컴퓨터에 의해 여러 종류의 파형이 디지털화하여 생성되며 4096워드의 외부 스태틱 RAM에 전송된다. 이와같이 RAM에 저장된 데이타는 D/A콘버터에 의하여 아날로그 전압파형으로 변환된다. 이 전압파형의 주파수는 클럭펄스에 의한 RAM의 읽기 속도에 좌우된다. 이와같이 생성된 전압파형이 유전체에 인가되며 이 인가전압과 함께 유전체의 응답전압이 샘플링되어 A/D콘버터에 의해 디지털 데이터로 변환된다. 컴퓨터는 응답전압 및 인가전압을 취하게 되며 마지막으로 복소유전률을 계산한다. 본 측정장치의 측정주파수 범위는 0.04Hz-10kHz이다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 The 8th Asian Symposium on Precision Forging ASPF
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• pp.158-161
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• 2003

Extrusion of forward-gear and backward-rod by combined extrusion with controlling the extrusion velocity using a counter tool is studied. In the combined forward-backward extrusion with controlling extrusion velocity, only parts with short gear can be formed. To obtain longer gear parts, extrusion with reverse ram motion is carried out after the combined forward-backward extrusion process. In this method, combined forward-backward extrusion is carried out until excessive extrusion length is attained and then, the motion of the punch is stopped and the counter tool is moved in the inverse direction and returned to the position for obtaining the desired extrusion length. The experiment is carried out by using lead for billets as a model material. With reverse ram motion, longer gear teeth without under-filling defect can be formed than that by only combined extrusion with controlling extrusion velocity.

• 한국신뢰성학회지:신뢰성응용연구
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• 제7권2호
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• pp.73-87
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• 2007

In this paper, based on the American weapon acquisition management framework in DoD Instruction 5000.2 "Operation of the Defence Acquisition System" and the contents of "DoD Guide for Achieving Reliability, Availability, and Maintainability" published by Defense Acquisition University, the kinds and roles of technical reviews are introduced and the identification of RAM related tasks which are performed at levels of technical reviews during acquisition process are considered. And the task allocations for developers, development managers, and users are proposed. Finally the relationships of acquisition management framework, technical reviews and RAM tasks are tabulated.

• 한국수소및신에너지학회논문집
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• 제31권5호
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• pp.459-466
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• 2020

As the hydrogen industry grows, expansion of infrastructure for hydrogen supply is required, but the safety of hydrogen facilities is concerned due to the recent accidents at the Gangneung hydrogen tank and the Norwegian hydrogen fueling station. In this study, the damage range and impact analysis on the on-site hydrogen fueling station was conducted using Hy-KoRAM. This is a domestically developed program that adds functions based on HyRAM. Through this risk assessment, it was evaluated whether the on-site hydrogen fueling station meets international standards and suggested ways to improve safety.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.255-255
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• 2010

Metal-Insulator-Metal 구조의 $Al_2O_3$ ReRAM 소자를 플라스틱 기판 위에 제작하였다. $Al_2O_3$ 박막은 원자층 증착 방법으로 $150^{\circ}C$의 저온 공정에서 15nm 두께로 증착하였으며, 하부와 상부의 전극으로는 DC 스퍼터링 방법으로 증착된 백금전극을 이용하였다. 플라스틱 기판위에 제작된 $Al_2O_3$ ReRAM 소자는 unipolar 메모리 특성을 보였다.

• 대한조선학회 특별논문집
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• 대한조선학회 2013년도 특별논문집
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• pp.90-93
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• 2013

RAM study has been used for various range of industry such as chemical, electronics, defense industry. Recently, in the offshore & shipbuilding industry, demand of owners to analysis risk has been increased. RAM study is a quantitative pointer to risk based design and provides effective method for improvements. This article shows the result of RAM study for LNG fuel supply system. The result provides information to improve design. This study shows how result of risk assessment affects the design of LNG fuel supply system.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2000년도 춘계학술대회논문집
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• pp.167-170
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• 2000

Recently the sub-micron structured substrates of 0.74 ${mu}ell$ track pitch and 800 $\AA$groove depth are required for DVD-RAM and the track pitch is expected to be narrower as the need for the information storage density is getting higher. For the accurate replication of the land-groove structure in the stamper to the plastic substrates it is important to control the injection -compression molding process such that the integrity of the replication for the land-groove structure is maximized. in the present study polycarbonate substrates were fabricated by injection comression molding and the land-groove structure regarded as one of mold temperature and the compression pressure on the integrity of the replication were examined experimentally. An efficient design methodology using the response surface method (RSM) the central composite design(CCD) technique and the analysis-of-variance (ANOVA) was developed to obtain the optimum processing conditions which maximize the integrity of the replication with a limited number of experiments.

• 한국해양공학회지
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• 제11권1호
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• pp.55-64
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• 1997

A wing operating in close proximity to the ground exhibits a reduction in induced drag, which increase the lift/drag ratio. The poert-augmented ram (RAR) phenomenon involves directiing the efflux from forward mounted propulsion ststem under the wings, with the efflux nearly stagnated under the wings. In the present paper, 3 dimentional PAR was numerically studied by solving the Navier-Stokes equations. Pressure distribution and velocity vectors are calculated around the wing surface and the ground. Through the numerical simulation, Cp values and lift/drag ratio are carefully reviewed by changing the height/chord; 0.05, 0.1, 0.3 and 0.8. The shape of model is NACA 0012 with a span/chord ratio of 3.0. According to the numerical results, the relationship between lift/drag and height/chord is fairly reasonable.