• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2007.11a
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• pp.113-117
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• 2007

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2005.05a
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• pp.267-271
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• 2005

• Journal of the Korean Society of Combustion
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• v.15 no.1
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• pp.22-29
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• 2010

In this study, carbon conversion was measured using an electronic mass balance. In a lab scale furnace, each coal sample was pyrolyzed in a nitrogen environment and became coal char, which was then gasified with steam under isothermal conditions. The reactivity of coal char was investigated at various temperatures and steam concentrations. The VRM(volume reaction model), SCM(shrinking core model), and RPM(random pore model) were used to interpret experimental data. For each model the activation energy(Ea), pre-exponential factor (A), and reaction order(n) of the coal char-steam reaction were determined by applying the Arrhenius equation into the data obtained with thermo-gravimetric analysis(TGA). According to this study, it was found that experimental data agreed better with the VRM and SCM for 1,000 and $1,100^{\circ}C$, and the RPM for 1,200 and $1,300^{\circ}C$. The reactivity of chars increased with the increase of gasification temperature. The structure parameter(${\psi}$) of the surface area for the RPM was obtained.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2103-2105
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• 1998

Switched Reluctance Motor is simple structure which used Accel/Decel application field because of cheap cost and High efficiency. For driving this motor, it is essential to need position sensor and driving converter. so, many topology and sensor have been studied untill now. Asymmetric Bridge Converter which has been known for the best control and efficiency is used chopping to control current of motor coil according to changing of motor speed. But this is embossed as a fault because it come to bring switching loss due to rapid switching frequency. In this paper, I applied to Soft Switching Mode by Partial Resonant Method to compensate these fault and to show the usabilityness of low switching device.

• Macromolecular Research
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• v.12 no.1
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• pp.53-62
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• 2004

We have prepared polymer composites of low-density polyethylene (LDPE) and ionomers (Surlyn 8940) containing polar segments and metal ions by melt blending with carbon black (CB) as a conductive filler. The resistivity and positive temperature coefficient (PTC) of the ionomer/LDPE/CB composites were investigated with respect to the CB content. The ionomer content has an effect on the resistivity and percolation threshold of the polymer composites; the percolation curve exhibits a plateau at low CB content. The PTC intensity of the crosslinked ionomer/LDPE/CB composite decreased slightly at low ionomer content, and increased significantly above a critical concentration of the ionomer. Irradiation-induced crosslinking could increase the PTC intensity and decrease the NTC effect of the polymer composites. The minimum switching current (Ι$\sub$trip/) of the polymer composites decreased with temperature; the ratio of Ι$\sub$trip/ for the ionomer/LDPE/CB composite decreased to a greater extent than that of the LDPE/CB composite. The average temperature coefficient of resistance (${\alpha}$$\sub$T/) for the polymer composites increased in the low-temperature region.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.4
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• pp.1-12
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• 2020

In this study, the effect of the social distance maintenance and pedestrian route system was analyzed for Seoul Station, one of the multi use facilities according to the COVID-19 pandemic. For analysis, the Seoul Station pedestrian network was established through the survey of the number of passengers and CAD floor plan. A pedestrian that maintaining Social Distance was implemented using the Social Force Model. Based on this, scenario analysis was proceed. As a result, when the walking line system was installed the average walking speed decreased compared to the current situation. but the average density was analyzed that maintain the walking level of service (LOS)'C', this mean walking line system is effective, and the effect of the walking line system was proved. It can be used as a pedestrian simulation model.

• Applied Chemistry for Engineering
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• v.19 no.6
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• pp.661-667
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• 2008

In this study, cholesteric liquid crystal (CLC) was synthesized and applied as a polarizing component on the optical film of back light units (BLU) for LCDs. After mixing CLC with nematic liquid crystal, this mixture was fulfilled in the module consisting of two films and then its amplifying efficiency and polarizing ability for a planarly emitted light were examined to apply as a BLU polarizer film for increasing the brightness of light. The properties of CLC compound were tested by UV/Visible spectroscopy and polarizing optical microscopy (POM). Flexible spacer was made by linear carboxylic acid group of cholesteric derivatives between cholesterol mesogen units for one-axis orientation in each layer. The CLC containing film could be used as a module to increase the ability of polarization and to enhance brightness of BLU and to widen wavelength range by stacking the films.

• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.16-20
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• 2020

On May 27, 2019, a non-native turtle was discovered at Ilsan Lake Park, Janghang-dong, Ilsandong-gu, Goyang-si, Republic of Korea. The turtle was identified as a western painted turtle (Emydidae: Chrysemys picta bellii) based on the external morphology, plastron color, plastron pattern, stripes on the side of the head, and shape of the carapace. In the lake park, another non-native turtle was observed sunbathing on the same rock. In this paper, we firstly reported the confirmed presence of a western painted turtle in the wild of Korea. Unfortunately, various non-native turtles are continuously reported in Korean ecosystems. Therefore, we highlight that continuous surveying and reporting of the non-native species is important to their management.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.283-291
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• 2006

Recently, a logistics between south and north Korea is rising rapidly by increasing of economical exchange between two Korea and growth of Gaeseoung Industrial Complex. Considering this trend of economic cooperation between two Korea, in addition to a land transportation route it is necessary to secure various logistics and transportation route. A barge transport system which has merits such as a little initial investment and convenience of harbor loading/unloading has been also used to transport freight widely in the EU and USA. In this paper, firstly, a social and economical feasibility study is performed about a shipping route which is using barge transportation system between Incheon and Gaesung. And also we propose several candidate shipping route and investigate a technical feasibility on a realistic possibility of shipping service by some investigation activities. Finally, the optimized shipping route and barge transportation system are proposed in this paper.

• Journal of Navigation and Port Research
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• v.31 no.1 s.117
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• pp.7-14
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• 2007

Recently, freight floe between south and north Korea is rising rapidly by increasing cf economical exchange between two Korea and growth of Gaeseoung Industrial Complex. Considering this trend of economic cooperation between two Korea, in addition to a land transportation route it is necessary to secure various logistics and transportation route. A barge transport system which has many merits such as a little initial investment and convenience of harbor loading/unloading has been also used to transport freight widely in the EU and USA. In this paper, firstly, a Gaeseoung industrial complex and its cargo transport are investigated and several candidate shipping routes which are using barge transportation system are proposed. And also we investigate a technical feasibility on a realistic possibility of shipping routes by some investigation activities. Finally, a suitable barge system of candidate shipping route(1) and(2) is proposed in this paper.