• Transactions of the Korean Society of Machine Tool Engineers
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• v.18 no.2
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• pp.123-129
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• 2009

Magnetron is a compartment of microwave oven and it generates the microwave. In this paper, the program HUSAP is developed in order to perform the heat transfer, structure, and fatigue analysis of magnetron. By using it we can make the geometry of magnetron and can solve the governing equations which are formulated by finite element technique. In order to achieve the reliability of HUSAP, we compare it with experiment and commercial software ANSYS. And comparisons of observed results show that agreement is remarkably consistent.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.126-131
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• 2001

Materials property data are necessary to secure the reliability of failure prevention techniques such as inspection and remaining life assessment of civil infrastructure and industrial facilities. However, there is no properly collected data in Korea, and those foreign data are hard to use because of the scattering of the sources, the difference of standards, etc. In this paper, materials property database system which has been constructed at Korea Research Institute of Standards and Science is introduced. Constructed database contains 145,000 numeric data of materials property for 600 kinds of metals and can be retrieved on the internet. The database system provides graphical user interface-based information searching functions necessary for the life evaluation and safety analysis.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.2
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• pp.357-363
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• 2001

This study examined the experience of vitamin/mineral supplement among adults in Seoul. Using a self-completed questionnaire including demographic information and use of vitamin/mineral supplement, 618 participants completed the study. The majority of respondents were female (72.2%), 40~49 years old (42.2%), and over college graduates (53.4%). Among the 618 respondents surveyed, 56% had experience of supplement use. The reasons for vitamin/mineral supplement use were health maintenance (56%), fatigue recovery (18%), disease prevention (8%), disease treatment (8%), and nutrition (8%) in order. The main considering factors for selecting vitamin/mineral supplement were side effect, cleanliness and reliability of company. The information sources for vitamin/mineral supplement were physician/pharmacist (45%), TV & advertisement (29%), family and relatives (19%). The main purchasing place for their supplement reported by the most of the respondents (84%) was from pharmacy.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.104-104
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• 2000

Among durability tests, the accelerated durability test has been widely used to evaluate the durability of vehicle structure and chassis pans in a shon period of time on the designed road which has severe surface conditions. However it increases the drivers fatigue mainly caused by the severe driving conditions. The drivers difficulty of maintaining constant speed and controlling the steering wheel reduces the reliability of test results. The durability test includes the position and distance sensing system for the recognition of the absolute and relative driving position, the driving control system for the control of whole driving circumstance, the emergency system for responding to system errors. AGVDS (Autonomous Guided Vehicle Driving System) was Proved to facilitate the development of now car projects. Therefore the AGVDS we propose will help make the fundamentals for all future traffic systems.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.555-558
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• 2013

A type of electric propulsion employed by specialized purpose vessels or offshore is the azimuth thruster. Azimuth thruster application had been increasing recently and resulted to excellent vessel maneuverability. However, this system is very complex and some of its major component being exposed under the seawater level presents difficulty in sealing design. For Polar class icebreaker operating in extreme sea condition, this requires a high level of reliability and safety. In this study, the characteristics of lubricating orifice pipe structural vibration installed at the lower reduction gear were investigated and analyzed through beam analysis theory and comparison of experiments. Propeller excitation and the resonant modes of vibration causing excessive vibration and suitable countermeasures to prevent damage due to vibration fatigue on the pipe are presented.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.393-398
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• 2002

Rubber isolator has properties that can adjust easily stiffness and can be formed various shape. Also, it has high damping and is effective about structure-borne noise at high frequency range, So, rubber mount has widely used to isolate vibration at industrial equipment and construction field. However, rubber material is nonlinear and require enough consideration about shape factor whenever it is designed. The purpose of this paper is to develop conical rubber mount using compression and shear elasticity. The first, the dimension of mount is calculated by theoretical analysis considering design condition and static characteristics have been analyzed by FEM method. In addition, the fatigue test of rubber mount is performed to get reliability for product life and dynamic stiffness test is executed to get dynamic magnification factor. Finally, transmissibility test of vibration isolator has been carried out to suggest normal quantity data about vibration isolation.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.7 no.1
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• pp.41-47
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• 2011

Residual stress is the key parameter for reliability and lifetime assessment because it can reduce the fatigue strength and fracture properties of industrial structures. Recently, instrumented indentation testing (IIT) has been widely used for evaluating it, since it does not need specific specimen and time-consuming procedure. However, conventional Oliver-Pharr method, which is used for calibrating contact depth to analyze indentation load-depth curve, cannot estimate plastic pile-up between indenter and surface of specimen. Here, we introduce f parameter which is the ratio of contact depth and maximum depth, to consider pile-up height. And, its application for evaluating residual stress of weldment is introduced.

• Journal of the Korean institute of surface engineering
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• v.35 no.4
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• pp.218-231
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• 2002

As the environmental regulation worldwide emerges, most notably in Europe and Japan, the elimination of Pb usage in electronic assemblies has been an important issue for microelectronics assembly due to the inherent toxicity of Pb. This has provided an impetus towards the development of Pb-free solders. A major factor affecting alloy selection is the melting point, since this will have a major impact on the other polymeric materials used in microelectronic assembly and encapsulation. Other important manufacturing issues are cost, availability, and wetting characteristics. Reliability related properties include mechanical strength, fatigue resistance, coefficient of thermal expansion and reactivity with substrate. In this article, Pb-free solder alloys have been proposed so far have been reviewed and are summarized.

• Journal of Ocean Engineering and Technology
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• v.10 no.2
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• pp.69-76
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• 1996

In-process quality control and high reliability of the weld are the major concerns in applying friction welding to the economical and qualified mass-production. Experimental examinations and quantitative analysis were performed for the optimiaztion of similar friction welding of hydraulic valve spool steels(SNCM220, SCM435, SACM645, SCM415, ${\varphi}24). The quantitative correlations were found between the initial cumulative counts of acoustic emission(AE) occurring during plastic deformation periods of the welding and the fatigue life as well as weld strength and welding conditions. A real-time evaluation system was developed for the friction weld quality by AE.

• Journal of Aerospace System Engineering
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• v.8 no.4
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• pp.7-17
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• 2014

Objective of this paper is to introduce a new technology known as prognostics and health management (PHM) which enables a real-time life prediction for safety critical systems under extreme loading conditions. In the PHM, Bayesian framework is employed to account for uncertainties and probabilities arising in the overall process including condition monitoring, fault severity estimation and failure predictions. Three applications - aircraft fuselage crack, gearbox spall and battery capacity degradation are taken to illustrate the approach, in which the life is predicted and validated by end-of-life results. The PHM technology may allow new maintenance strategy that achieves higher degree of safety while reducing the cost in effective manner.