• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.906-909
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• 2004

Status of high intensity LED, one of the recent issue in industry is reviewed. In a system view, various power supply methods for multiple array construction are introduced rather than one for single LED. Custom IC for driving LED and different circuit for applications are also considered.

• Journal of the Korean Society of Safety
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• v.33 no.5
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• pp.1-8
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• 2018

A fuel cell is an energy conversion device that converts a chemical energy directly into an electrical energy and has higher energy efficiency than an internal combustion engine, but solid oxide fuel cell (SOFC) consisting of brittle ceramic material remains as a major issue regarding the mechanical properties as the crack formation and propagation. In this study, the stress distribution and crack behavior around the crack tip were evaluated, due to investigated the effects of the surface crack at the operating condition of high temperature. As a result, the difference of the generated stress was insignificant at operating conditions of high temperature according to the surface crack length changes. This is because, the high stiffness interconnect has a closed structure to suppress cell deformation about thermal expansion. The stress intensity factor ratio $K_{II}/K_I$ increased as the crack depth increased, at that time the effect of $K_{II}$ is larger than that of $K_I$. Also the maximum stress intensity factor increased as the crack depth increased, but the location of crack was generated at the electrolyte/anode interface, not at the crack tip.

• Journal of the Optical Society of Korea
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• v.4 no.2
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• pp.75-78
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• 2000

We design a high temperature oven for measuring the saturation intensity of the transition line $4f^ 6/6s^{2 7}7F_0 ↔ 4f^6/6s6p $^1$P(J = 1)$ of the samarium atom. We first constructed a high temperature oven to generate the samarium vapor column and study the thermal characteristics of the oven. The oven is able to operate at a temperature up to about 1400 $^{\circ}C$ and the operation is tested by using several metals with high melting points. We describe two wave mixing experiment with the samarium vapor generated in the high temperature oven and obtain the saturation intensity by analyzing the first diffraction signal.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.151-151
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• 2022

The impact of raindrops on the soil surface causes soil detachment, which may be estimated by measuring the kinetic energy (KE) of the raindrops. Since direct measurements of rainfall force on ground surfaces are not generally available, empirical equations are an alternative option to estimate KE from rainfall intensity (I), which has the greatest influence over soil erosion and is easily accessible. Establishing the optimal formulation for the relationship between kinetic energy and rainfall intensity has proven to be difficult. Thus, this research considered thirty-seven rainfall events observed from June 2020 to December 2021 using a laster optical disdrometer erected in Kyungpook National University to examine the characteristics of KE-I relationships. We concentrated our discussion on the formation of two different expressions of the KE, including KE expenditure (KE_exp) and KE content (KE_con). The following conclusions were drawn: (1) We employed statistical analysis to demonstrate that the KE_exp is more suitable expression for establishing an empirical rule between KE and I than the KE_con. (2) A power-law model was used to find the best correlation between KE_exp-I relationship, whereas the best match between KE_con and I were found using an exponential equation.

• Journal of The Geomorphological Association of Korea
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• v.19 no.2
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• pp.133-143
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• 2012

To evaluate the kinetic energy of the raindrops, the drop size distribution and the terminal velocity of the raindrops had been measured from January to September 2010 using the laser-optical disdrometer in KIGAM, Daejeon, Korea. The relationship between kinetic energy (KE) and rainfall intensity (I) was computed as logarithmic and exponential model, respectively, under the rainfall intensity of about 142mm/h. The exponential model is more suitable for the relationship of KE-I than the logarithmic model, because the exponential model presented better fit for KE over 50mm/h of rainfall intensity. Meanwhile, the differences of the total kinetic energy existed in rainfall events with almost same total rainfall depth, and KE values of Daejeon at high rainfall intensity underestimated rather than the others under temperate climate. Therefore, these differences of KE in rainfall events and geographical regions imply the result from the variations of rainfall intensity within a rainfall event.

• Environmental and Resource Economics Review
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• v.20 no.1
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• pp.1-31
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• 2011

By employing Environmental Input-Output Table 2005, which has 76 intermediate sector and 21 energy sources, this paper analyses the flow of energy demand and $CO_2$ after estimating an induced $CO_2$ emissions from 76 industrial sectors. Index of $CO_2$ intensity($CO_2/GDP$) and other index of $CO_2$ intensity($CO_2/calory$) showed that final demand sector uses more high calory energy source. Intermediate sector used less environmental friendly energy source and emit more $CO_2$ at same calory. Industries those has high induced $CO_2$ emissions are Thermal Power($32.587CO_2-g/Won$), Cement($10.370CO_2-g/Won$), Road Transportation($7.255CO_2-g/Won$), Cokes and Other Coal Products($5.791CO_2-g/Won$), Steam and Hot water supply, Sewage, Sanitary services($4.575CO_2-g/Won$). It is shown that industry such as Iron and Steel which has low $CO_2$ intensity, high backward linkage effect and high forward linkage effect makes high induced $CO_2$ emissions. Environmental load and $CO_2$ emissions in overall economy will decrease when not high $CO_2$ intensity industry but also low $CO_2$ intensity industry makes lower $CO_2$ intensity.

• Journal of Distribution Science
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• v.18 no.1
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• pp.71-83
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• 2020

Purpose: Because the energy consumption, economic growth and logistics development are still the heated topics which have attracted many scholars' interests. Therefore, this paper attempts to analyze the effect of logistics development on the economic growth, explore the effect of the economic growth on energy consumption and to discuss the effect of the logistics development on energy intensity. Research design, data and methodology: Using the panel data over the period 2000-2017 of 156 countries and employing the country & year fixed effect model, system generalized method moments and random effect model, the empirical analyses of this propositions are performed. Results: The empirical findings present that the logistics development is positively related to the economic growth. The energy consumption in the t-1 period and economic growth are positively related to the current energy consumption. The logistics development is negatively related to the energy intensity. Meanwhile, the empirical findings also indicate that there is a great difference about these effects among the four sub-samples (low income 18 countries, low middle income 49 countries, upper middle income 44 countries, high income 49 countries). Conclusions: Based on the evidences in this paper provided, we can find that these variables can affect each other.

• Progress in Superconductivity
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• v.10 no.2
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• pp.69-73
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• 2009

For extraction of the self-energy from the angle resolved photoemission spectroscopy(ARPES) experiments for the cuprate superconductors, the momentum distribution curve(MDC) analysis is commonly used. There are two requirements for this method to work: the self-energy is momentum independent and the bare electron dispersion is known. Assuming that the first condition is satisfied in the cuprates, we checked the effects of the bare dispersion on the extracted self-energy. For this, we first generated the ARPES intensity using the tight-binding band of the B2212 by solving the Eliashberg equation. We then extracted the self-energy from the theoretically generated ARPES intensity using the linear and quadratic dispersions. By choosing the bare dispersion such that the Kramer-Kronig relation is best satisfied between the real and imaginary parts of the extracted self-energy, we confirmed that the quadratic dispersion is better for the bare electron band for Bi2212. The self-energy can be reasonably extracted from the ARPES experiments using the MDC analysis.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.4
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• pp.26-31
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• 2010

Finding sufficient supplies of clean energy for future is one of the society's most important challenges according to technologies. Alternative renewable energy source such as solar energy can be substituted for exceeding human energy need. The main factor affect to solar performance is a collective intensity. To enhance intensity, suitable equipment is a solar tracker. The solar tracker consists of sun point detector module, mechanical mechanism module with actuator and control system module. This paper presents sun point detector for solar tracker of daylight system. To evaluate the detecting accuracy, an experimental device is implemented. In experimental results, the accuracy of development system has under 0.11%/0.5deg.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.752-754
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• 1997

The stress intensity factor for an interface crack in dissimilar materials has been obtained by many researchers. But research of the energy release rate for an interface crack in pseudo-isotropic dissimilar materials is insufficient yet. In this paper, the energy release rate for cracks in pseudo-isotropic dissimilar materials was obtained using eigenfunction expansion method and also analyzed numerically using the reciprocal work contour integral method. The results were verified by comparing with other worker's results.