• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.8
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• pp.86-93
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• 1995

Linwidth enhancement factor .alpha., linwidth, chirping and differential gain characteristics were measured and compared for each DFB-LDs containing active layers composed of bulk, MQW, and S-MQW, respectively. .alpha. of 6, 4 and 3.2 and chirping measured under 2.5Gbps modulation of 1.29nm, 0.67nm and 0.48nm were given for DFB-LDs of bulk, MQW and S-MQW active layers, respectively. And S-MQW has the largest differential gin of 2.4*10$^{-15}$ cm$^{2}$ (S-MQW) compared to the of 5.4*10$^{-16}$ cm$^{2}$(bulk) and 8.6*10$^{-16}$ cm$^{2}$(MQW). Linewidth enhancement facter .alpha. of less than 2 is expected with p-type modulation doped S-MQW DFB-LD.

• Korean Journal of Health Education and Promotion
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• v.28 no.3
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• pp.17-29
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• 2011

Objectives: This study was to explore how elderly with chronic disease in a health management program managed their health and to describe their health management strategies. Methods: The data were collected through in-depth interviews, with a purposeful sample of twelve in an urban community. The collected information was analyzed through grounded theory approaches by Strauss and Corbin. Results: Though open coding process, 35 concepts, 17 subcategories, 8 categories were identified. As for the participation experience process, four stages had surfaced, namely, 'Perception of chronic disease', 'Concerned about health', 'Developing life pattern', 'Restoring health'. These processes were within 'Restoring Health Equilibrium', core category. Consequently, the participants revealed in restoring relationship-oriented life and settling in family-focused life. Conclusions: These findings have implications for the understanding of health promotion for the elderly with chronic diseases and contributing to make a basic data for developing elderly health management program.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.11a
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• pp.110-113
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• 1992

This paper presents the results on experiments of relative dielectric constant dielectric loss, conductivity change and breakdown voltage of the L.D.P.E. mixed with Dodecyl Alcohol. The frequency range is 0.1 - 20 MHz and temperature, 20 - 80 $^{\circ}C$. Dielectric properties were similar to those of nonpolar polymers. Until $60^{\circ}C$ the conductivity value of compound was decreased with temperature increasment. And, its breakdown voltage was measured higher, about 3-4KV, than that of the pure L.D.P.E.. Also the amount of remnants of DA in the compounds were considered.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1716-1718
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• 1996

It is well known that the metallophthalocyanine (MPcs) are sensitive to toxic gaseous molecules such as $NO_2$ and also chemically and thermally stable. Therefore, lots of MPcs are studied for the potential chemical sensor for $NO_2$ gas using quartz crystal microbalance(QCM) or electrical conductivity. In this study, thin films of octa(2-ethylhexyloxy) copper-phthalocyanine were prepared by Langmuir-Blodgett method and characterized by using UV-VIS spectrascopy and ellipsometry. Transfer condition, film characterization, and preliminary results of current-voltage(I-V) characteristics of these films exposed to $NO_2$ gas as a function of film thickness will be discussed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.10
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• pp.659-664
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• 2016

Thermal and electrical conductivities of the natural, artificial, and expandable graphites were analyzed after treatment in NaOH aqueous solution. In order to investigate the elimination of the oxidized groups and impurities on the graphite surfaces after NaOH treatment, the graphite samples were structurally characterized by using XRD, XPS, Raman, FE-SEM. The thermal and electrical conductivities of the graphite samples were significantly improved after NaOH treatment. These results were caused by the structural rehabiliation.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.216-219
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• 2008

The Power LED is more much than 1W and appliable to lights that is different from signal LED. In this paper we investigated types of tests in reliability assessment standards on Power LED. we make comparison of that military standards, JEITA(Japan Electronics and Information Technology Industries Association) and JEDEC(Joint Electron Device Engineering Council) with RS(reliability standard). Reliability tests should be considered that informations can be obtained from requirements of a real system Therefore, The paper aided companies to criteria for reliability tests by themselves.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.11a
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• pp.167-169
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• 2000

최근의 대기확산 모델링은 도시규모 뿐만 아니라 동북아지역의 대기오염물질 장거리이동 현상을 다루는 빈도가 매우 높아졌다. 모델링을 위해서는 기상자료와 배출량자료를 준비하는 것이 매우 중요한 과정이다. 본 연구에서는 우리나라 주도로 수행중인 '동북아 장거리이동 대기오염물질 공동 조사사업(LTP project)'과 관련하여 모델링분야의 공동 수행과제인 SO$_2$ 및 NOx 배출량 산정에 관한 것을 소개하였다. UNDP가 제안한 배출원 목록 수립방법을 이용하여 1998년에 대한 1$^{\circ}$$\times$ 1$^{\circ}$ 간격의 격자형 자료가 산정되었으며, 향후 LTP project의 모델링분야에서 활용될 예정이다. (중략)

• Journal of Korean Society for Atmospheric Environment
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• v.10 no.4
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• pp.217-223
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• 1994

Carbon dioxide emission has been increased by 7% in an annual average toward 212.5 million tons in 1990 from 108.7 million tons in 1980. Among emissions in 1990, industry, residential / commercial, transportation, other and non-energy have occupied 91.12, 68.04, 42.13, 7.13 and 4.09 million tons respectively. The Korea-scenarios corresponding to those of IPCC that is Intergovernmental Panel on Climate Change (A : modest control of $CO_2$; B : stringent control of $CO_2$, C: shifting fuel to renewable and nuclear energy in the second half of the next century ; and D: shifting fuel to renewable and nuclear energy in the first half of the next century show that the global-scale contributions of atmospheric $CO_2$ concentration are 0.77, 0.64 and 0.78% in 2050 for cases A,B, and C respectively. In all cases, the contributions were smaller than 0.09 % in 1985.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.350-355
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• 2003

Flame onset and propagation within hydrogen premixed gas mixture are numerically investigated in an rectangular enclosure. A detailed chemistry for hydrogen reaction is applied to anticipate the thermochemical behavior of intermediate species appropriately. To facilitate computation, 10 species and 16 elementary reaction steps for hydrogen combustion are taken into account. On the basis of 30 % of hydrogen concentration in hydrogen-air mixture, the effects of position and quantity of ignition sources on the flame evolution are analyzed. From the simulation results, the means that can lessen the possible hazard caused by flame propagation are suggested.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.518-521
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• 2003

A new measurement system was developed by fault diagnosis system for traction motor using current signal analysis. The motor current signature analysis method is used for traction motor fault diagnosis. The diagnosis system program is constructed by artificial neural networks algorithm, those results from the program are used to train neural networks. The trained neural networks have the ability to compute adaptive results for non-trained inputs, and to calculate very fast due to original parallel structure of neural networks with high accuracy within destined tolerance. This system suggested that available test for checking, the probable extent of aging, and the rate of which aging is taking place.