• Journal of the Microelectronics and Packaging Society
• /
• v.27 no.2
• /
• pp.45-51
• /
• 2020

As flexible electronics will be used under high temperature and high humidity with repeated bending deformations, the effects of environmental condition and repeated mechanical deformations are considered simultaneously to achieve long-term reliability. In this study, the mechanical reliability of metal electrodes (Al, Ag, Cu) deposited on flexible polymer substrate is investigated under 4 different conditions: with and without repeated mechanical deformations and normal environmental or high temperature and high humidity conditions (85℃/85%). The mechanical failure does not occur in all the metal electrodes without mechanical deformation even under high temperature and high humidity conditions. The electrical resistance of metal electrode increased about 400% to 600% after 100,000 bending cycles under normal condition. For high temperature and high humidity condition, the electrical resistance of Al and Ag increased similarly. However, the resistance of Cu during bending fatigue test under high temperature and high humidity condition increased over 90000% because of the combined effect of corrosion and mechanical fatigue. This study can give a helpful information for designing electrode materials with high mechanical reliability under high temperature and high humidity.

• 월간 기계설비
• /
• s.48
• /
• pp.33-43
• /
• 1994

지난해 우리 협회와 부산시가 행정쇄신 과제중의 하나로 제안한 기계설비공사 분리발주가 행정 쇄신위원회에서 결정$\cdot$통과돼 6월30일 재무부가 예산회계법시행령을 개정, 발주기관이 기계설비공종을 건축에서 별도로 분리 발주할 수 있도록 함에 따라 일반건설업체로부터 저가에 하도급을 받아 공사를 하던 설비전문업체들은 관련공사를 원도급에 의한 적정 가격에 수주받을 수 있어 각종 기계설비 공종에 대한 품질향상이 기대된다.

• Korean Journal of Construction Engineering and Management
• /
• v.9 no.1
• /
• pp.155-166
• /
• 2008

The Equipment Expenses section of the Poom-Saem that is used for Construction Cost Estimation of public sectors in Korea has been rarely revised, and so does not reflect changes of Construction Equipment technology and construction methods, since it was established based on data from Japan and the U.S in the early 1960s. In order to make reasonable estimation of equipment expenses for a bulldozer and a loader, the domestic and overseas documentary records were investigated. Further, 16 construction sites were visited, and 20 Construction Equipment leasing services were surveyed. The optimum level of each item which consists of equipment costs was revealed based on the result of the analysis on the figures of equipment costs calculation from the Poom-Saem and the collected data. The research will be the foundation for applying the rapid development of Construction Equipment and technology to the appropriate cost estimations and the ground work of related studies.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.16 no.6
• /
• pp.1216-1220
• /
• 1992

In case that a general cusp-crack shaped inclusion expressed in a polynominal form of conformal mapping function exists in a two dimensional elastic body under uniform heat flow, the complex potential and thermal stress intensity factors are derived. Two thermal boundary conditions are considered, one an insulated rigid inclusion and the other a rigid inclusion with fixed boundary temperature. The previous solutions of the thermal stress intensity factors for symmetrical airfoil and lip type rigid inclusions are obtained from the general solution of the thermal stress intensity factors.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.17 no.2
• /
• pp.248-256
• /
• 1993

This paper deriver the generalized mass to find dynamic characteristics and its derivatives of a continous system. And a new sensitivity analysis method is presented by using the amount of change of generalized mass and vibrational mode caused by the variation of lumped and distributed mass. In this paper, to get or detect appropriate results, cantilever beam and stepped beam are used. Deviations of sensitivity coefficient, natual frequency, vibrational mode and transfer function are calculated as result, and compared with the theoretical exact values.

• Journal of the KSME
• /
• v.26 no.3
• /
• pp.214-218
• /
• 1986

제 4절에서 얻은 연속체 일반의 장방정식들을 제 5절에서와 같이 각종 물질의 구성방정식으로 보충하므로써, 탄성이론, Newton 유체역학, 비 Newton 유체역학, 소성이론, 점탄성이론, 비균질 체역학, 연속체 일반의 열역학 ...등의 기본적 이론체계를 구성할 수 있다. 또 합당한 경계조건과 함께 구체적 해를 얻는 다양한 연구로 이어진다. 이에 대한 독자의 편의를 위하여 몇 개의 문 헌을 뒤에 나열한다. (8,15,16,17,18,19) 공학의 한 분야에 전문적인 지식을 얻기 위해서는 공학 일반(engineering science)에 대한 선명한 이해가 필수적이며 이를 위해 연속체이론이 꾸준히 연구되고 있다. 그러나 이와 같은 방대한 체계를 $E_{3}$ 해석학의 틀 속에서 선명하게 파악 하려하는 것은 어려운 일이다. 결국 대역적해석학(global analysis)의 응용(3,5,20,21,22)이 불가 피하지 않나 생각된다. 이 방향의 연구가 선진국에서도 아직 소수의 학자들에 국한된 실정이나, 우리 공학의 획기적 발전을 위하여 독자들의 노력이 계속되었으면 한다.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2002.02a
• /
• pp.204-209
• /
• 2002

본 실험은 주택용, 일반용, 교육용, 산업용, 농사용, 심야전력 등 국내의 종별요금체계에 따라 인공광을 이용한 접목묘 활착촉진장치에서 소비된 전기에너지와 전력요금을 비교하고자 수행되었다. 그 결과 전력요금은 일반용>교육용>산업용>심야전력>농사용의 순서로 나타났으며 접목묘 1주를 활착시키는 데 필요한 전기요금은 농사용의 경우 9.24원이었으며, 일반용 전력요금과 비교할 때 봄과 가을, 겨울, 여름철의 1주당 생산단가는 각각 2.3배, 2.4배, 3.4배로 나타났다. 또한 본 실험에서 소비된 전력은 컴프레서, 가열기, 조명, 가습기, 송풍기의 순서로 각각 28%, 57%, 11%, 3%, 1%로 나타났다. 활착촉진장치에서 소비된 전력 가운데 공조 시스템, 즉 냉·난방이 차지하는 비중이 전체의 85%로서 매우 높게 나타난 바, 공조 시스템에 대한 전력소모량의 절감 방안이 우선적으로 강구되어야 할 것으로 판단된다.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2007.11a
• /
• pp.503-508
• /
• 2007

The Equipment Expenses section of the Poom-Saem, that is used for Construction Cost Estimation on public sectors in Korea, has been rarely revised, and so does not reflect changes of construction equipment technology and construction methods, since it was established based on data from Japan and the U.S in the early 1960s. In order to make reasonable estimation of maintenance costs(Interest, Storage, Insurance, Tax), the equipment expenses section of the Poom-Saem and the domestic and overseas documentary records were investigated. Further, 16 construction sites were visited, and 20 Construction Equipment leasing services were surveyed. Based on results from analysing figures related with the estimation of maintenance costs, the maintenance cost is redefined. Then, construction equipment was classified into 6 exclusive construction equipment and general one, and realistic figures of the maintenance cost, which consists of interest, storage, insurance, tax, are suggested respectively. The optimum level of each item which consists of equipment costs was revealed based on the result of the analysis on the figures of equipment costs calculation from the Poom-Saem and the collected data. The research will be the foundation that helps to estimate appropriate construction costs and the ground work of related studies.

• Journal of the Society of Disaster Information
• /
• v.7 no.1
• /
• pp.32-42
• /
• 2011

Many researches have been conducted to evaluate the performance of modified asphalt concrete mixtures. The research was conducted to estimate the laboratory mechanical characteristics of Elvaloy-modified asphalt concrete mixture. To achieve its intended objective, indirect tensile test and resilient modulus test were performed. The rest results revealed that indirect tensile strengths and resilient moduli of the Elvaloy-modified asphalt concrete mixture were higher than those of the conventional dense-graded. As a result, within the limits of the tests conducted in this research, it is predicted that the performance and stability of the Elvaloy-modified asphalt concrete mixture are better than that of the conventional dense-graded one.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.9 no.5
• /
• pp.683-690
• /
• 1985

본 논문에는 Euler매개변수를 회전좌표계로 사용하여 구속된 3차원 기계시스템의 역동학력 해 을 수행한 연구결과가 수록되었다. 해석을 위해 문제에 등장하는 비선형 Holonomic구속조건식 들과 운동방정식들을 Cartesian일반좌표계을 사용하여 표시하였으며, 일반좌표계를 구성하는 각 강체의 좌표계로는 변위를 나타내기 위한 3개의 좌표와 회전을 나타내기 위한 4개의 Euler매 개변수가 사용되었다. 구속조건식들과 미분방정식 형태의 운동방정식들을 결합하여 시스템 전 체의 운동방정식을 유도하기 위해 Lagrange승수 기법을 사용하였다. 각 강체의 주어진 시간에 서의 위치, 속도, 가속도는 기구학적 해석(kinematic analysis)을 통해 얻어지고, 이 자료들을 전 체운동방정식에 대입하여 Lagrnage승수의 값을 계산하여 6개의 자유도를 가진 로봇 기구를 원 하는대로 운전하는에 필요한 각 관절의 토오크를 계산하였으며, 계산결과가 정확하다는 사실이 입증되었다. 연구결과 Euler매개변수를 회전좌표로 사용할 경우 특이 경우(singular case)가 발 생하지 않으며, 이 방법은 역동력학 해석용 다목적 전산프로그램 개발에 광범위하게 응용될 수 있음이 밝혀졌다.