• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.531-532
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• 2007

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1734-1739
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• 2007

The materials characteristics and lifetime evaluation are very important in design procedure to assure the safety and reliability of rubber components. This paper discusses the failure mechanism and material test were carried out to predict the useful life of NBR and EPDM rubber mount for compression motor which is used in refrigerator. In order to investigate the heat-aging effects on the materials properties, stress-strain curve were obtained from the results of material tests. Compression set results changes as the threshold are used for assessment of useful life and the time were plotted against reciprocal of absolute temperature to give the Arrhenius plot.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.923-931
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• 2008

Coupling rubber pad are important components in railway vehicles. It can be used for reduce shock, vibration and noise. Simple tension, equi-biaxial tension and pure shear test were performed to acquire the coefficient of rubber material which were Mooney-Rivlin and Ogden model. The finite element analysis was executed to evaluate the behavior of deformation and stress distribution by using the commercial finite element analysis code. Useful life evaluation are very important in design procedure to assure the safety and reliability of the rubber components. In this paper, useful life prediction of rubber pad for railway vehicle were experimentally investigated. Accelerated heat-aging test for rubber material were carried. Compression set results changes as the threshold are used for assessment of the useful life and time to threshold value were plotted against reciprocal of absolute temperature to give the Arrhenius plot.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.104-111
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• 2006

The non-linear properties of rubber material which are described as strain energy function are important parameter to design and evaluate of rubber spring. These are determined by material tests which are uni-axial tension and bi-axial tension. The computer simulation using the nonlinear element analysis program executed to predict and evaluate the load capacity and stiffness for chevron spring. In order to investigate the heat-aging effects on the rubber material properties, the acceleration test were carried out. Compression set results changes as the threshold are used for assessment of the useful life and time to threshold value were plotted against reciprocal of absolute temperature to give the Arrhenius plot. By using the compression set test, several useful life prediction for rubber material were proposed.

• Journal of the Korean Solar Energy Society
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• v.35 no.3
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• pp.81-91
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• 2015

LED has received intensive research attention due to its long life, high efficacy, fast response and wide colour availability, and has secured extensive application areas. However, LED chips within the modules convert only fraction of electric energy into light, and majority of supplied energy needs to be dissipated as heat, which challenges in the performance and life of the LED modules. IEC 62717 specifies the performance requirements for LED modules together with the test methods and conditions. The present study examined the influence of different design parameters on performance temperature through series of experiments and numerical simulations. The economic means to change the module performance temperature during the measurement of mandatory markings were suggested based on predicted cooling performances.

• Korean Journal of Occupational Health Nursing
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• v.12 no.2
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• pp.110-122
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• 2003

Purpose: The purpose of this study is to make a systemic assessment on the level of self-efficacy, social support, and accessibility to medical services, health status, health promoting behaviors, and the quality of life of workers in small scale enterprises. RECEDE model developed by Green and Kreuter for the purpose of a comprehensive assessment research was used. Method: The number of subjects was 199 workers in small scale enterprises at Youngdeungpo-gu and Sungdonggu, Seoul. Data were collected between October and December, 200 through a self-reported questionnaire. And data were analyzed by descriptive statistics, t-test, and F-test. Result: 1. The level of quality of life was 3.08, and general health status was 2.75. There was no significant difference by sex, age, marital status, job, and perceived health status. 2. The level of health promotion life style was 2.09. There was no significant difference by sex, age, marital status, and job. But there was significant difference by perceived health status. 3. The level of self-efficacy, social support and accessibility to medical services were 3.04, 2.85, and 1.45. Conclusion: The results of this study suggest that it is necessary to develop the systematic health promotion programs that can strengthen self-efficacy and health status, and supplement social support and accessibility to medical services, and to encourage health promoting behavior in order to improve quality of life for workers in small scale enterprise.

• Proceedings of the Korean Society of Life Science Conference
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• 2007.10a
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• pp.46.2-46.2
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• 2007

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• The Journal of the Korea Contents Association
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• v.11 no.12
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• pp.347-356
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• 2011

The aim of this study was to determine the prevalence of self-assessment halitosis and to offer the basic information that establishes a strategy of effective health promotion and to enhance the quality of life. This study performed a questionnaire survey. The questionnaire was filled out by the 362 adults, who lived in Incheon Metropolitan City from May to July, 2010. The data were analyzed using a Chi-square test in the SPSS version 12.0 program. The prevalence rate of self-assessment halitosis was 24.3%. Hypertension, diabetes, medication and inadequate oral hygiene practice were significantly associated with self-assessment halitosis. Other factors of self-assessment halitosis were older age and occupation. As a result, dental professionals have to investigate a systemic disease history thoroughly. And they have to educate regular checkup of oral health and to perform a continuous feedback. The self-assessment halitosis has a negative influence on mental health and social life, so dental professionals must take into consideration about the halitosis.

• Journal of Applied Reliability
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• v.9 no.2
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• pp.131-148
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• 2009

An organic light emitting diode (OLED), also light emitting polymer (LEP) and organic electro luminescence (OEL), is any light emitting diode (LED) whose emissive electroluminescent layer is composed of a film of organic compounds. The layer usually contains a polymer substance that allows suitable organic compounds to be deposited. They are deposited in rows and columns onto a flat carrier by a simple "printing" process. The resulting matrix of pixels can emit light of different colors. Such systems can be used in television screens, computer displays, small, portable system screens such as cell phones and PDAs, advertising, information and indication. OLEDs can also be used in light sources for general space illumination, and large-area light-emitting elements. In this paper, we develop the general guide line of the accelerated life test for assuring B10 life of AMOLED(Active Matrix Organic Light Emitting Diode) and PMOLED(Passive Matrix Organic Light Emitting Diode) which are widely used for display monitor less than 115 mm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.2117-2125
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• 2009

This paper describes an information system of operation adequacy in environmental facilities such as environmental contamination prevention and processing equipments, which is namely, an integrated management system for environmental facilities. By developing this system, we can improve environmental characteristics and maximize the efficiency throughout the life cycle from generation of contaminant source to contamination prevention processing, and to contaminant disappearance. In order to meet these objects, we have developed ubiquitous life cycle assessment(u-LCA) for environmental facilities, which is an ISO14001-based incineration facility information system. The developed system is currently operating for test at an incinerator in Koyang city. Due to this system, the managers can confirm the operation condition of the incinerator with real-time and they will be able to improve the problems immediately.