• Journal of the Korean Ceramic Society
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• v.29 no.1
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• pp.48-52
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• 1992

Indium tin oxide (ITO) layers are of considerable interest on account of the combination of properties they provide high electrical conductivity, high infrared reflection with high solar energy transmission, high transmission in the visible range. We are concerned about the variation of the spectral transmittances and sheet resistances as the thickness of SiO2-ZrO2 barrier layer and ITO layers and heat treating conditions are changed. Transmittances and reflectivities were studied by measuring UV-VIS-NIR-, FT-IR spectroscopy. ITO films are crack free, homogeneous and of polycrystalline cubic structure. The microstructure of good ITO films shows a narrow grain size distribution and mean value of 100 nm. The selectivity of absorbing properties is improved by increasing the thickness of ITO films. The increase of sheet resistance of ITO films are due to the increase in the reaction between films and glass substrate.

• Journal of Hydrogen and New Energy
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• v.8 no.2
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• pp.51-56
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• 1997

The Zr-based Laves phase, $ZrV_2$ hydrogen storage alloy is not suited for the electrode of Ni-MH battery, because the binding strength of that with hydrogen is too strong although the storage capacity is high. For an application to electrode a part of V in alloys is substituted with Ni to make weaken the binding strength. The electrochemical and thermodynamic properties of Zr-V-Ni system alloys are investigated from the equilibrium potential and studied the possibility for the application to the rechargeable battery electrode.

• Journal of Mechanical Science and Technology
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• v.16 no.1
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• pp.32-38
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• 2002

The purpose of this study is to analyze the collapse characteristics of widely used spot welded section members (hat and double hat section, nembers of vehicles) which possess the greatest energy absorbing capacity In an axial impact collapse. This study also suggests how the collapse load and deformation mode are obtained under impact. In the program system presented in this study, an explicit finite element code, LS-DY7A3D, is adopted for simulating complicated collapse behavior of the hat and double hat shaped section members with respect to section dimensions and spot weld pitches. Comparing the results with experiments, the simulation has been verified under a velocity of 7.19 m/sec (impact energy of 1034J)

• Journal of Mechanical Science and Technology
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• v.15 no.2
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• pp.180-191
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• 2001

The widely used spot welded sections of automobiles(hat and double hat shaped section members) absorb most of the energy in a front-end collision. The sections were tested with respect to axial static(10mm/min) and quasi-static(1000mm/min) loads. Based on these test results, specimens with various thicknesses, width ratios and spot weld pitches on the flange were tested at high impact velocity(7.19m/sec and 7.94m/sec) which simulates an actual car crash. Characteristics of collapse have been reviewed and structures for optimal energy absorbing capacity is suggested.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.604-608
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• 2010

This paper proposed a new 2D multibody dynamic modeling technique to analyze overriding behavior taking place during train collision. This dynamic model is composed of nonlinear spring, damper and mass by considering the deformable characteristics of carbodies as well as energy absorbing structures and components. By solving this dynamic model of rollingstock, collision energy absorption capacity, acceleration of passenger sections, impact forces applied to interconnecting devices, and overriding displacements can be well estimated. For a case study, we choose KHST (Korean High Speed Train), obtained crush characteristic data of each carbody section from 3D finite element analysis, and established a 2D multibody dynamic model. This 2D dynamic model was suggested to describe the collision behavior of 3D Virtual Testing Model.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.270-282
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• 1996

The four subjects which we human beings are going to face and negotiate toward the 21 st century are (1) Population , (2) Food 93) Energy and (4) Environment . In this paper, rice is recommended and proposed as one of the most valuable key resources for the purpose of covering those four subjects with harmonic progress and promotion of the economic development and growth . The historical background and the current status force producting in world wide were reviewed. To meet those subjects, various methods of utilizing rice were introduced and proposed, how could be usefully utilized and processed as food, energy and the role played by rice plant in absorbing carbon dioxide produced.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1997.04a
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• pp.233-240
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• 1997

Seven kinds of hysteric model were used and classified three groups considering the absorbing capacities of strain energy for each model. Four kids of each model. Four kinds of strong motion earthquake record (two of them were recorded in Japan and the others in U.S.A) are used. The yield strength of building was set in the ratio to the maximum input acceleration (Yield Strength / Maximum Acceleration = 0.5~3.0). Natural periods of structures were varied 0.1~3.0 second with an interval of 0.1 second. First group : Elastic-Plastic model, Ramberg-Osgood model Second group : Degrading Tri-liner model, Takeda model Third group : Slip model, Origin model, Max-D model Elastic-plastic response spectra were calculated for response velocities, displacement, energy input, ductility factors, accumulated ductility factors. The equivalent response values of M.D.O.F systems against S.D.O.F system were calculated to compare the relationship of two systems.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1213-1220
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• 2008

In this study, the crashworthy design guidelines for the high speed EMU were derived and numerically evaluated. As for this high speed train, there are several different features from the KTX in that the conventional type bogies are adopted and the front end car (TC car) accommodates passengers. It is natural that the impact acceleration of the front end car should be controlled under the appropriate level stipulated at safety regulations for collision accidents. Also, car-to-car interfacing structures and devices should be deliberately designed to prevent overriding and telescoping mechanisms. As the first step for these design countermeasures, it was studied that how much impact energy should be absorbed at the energy absorbing zones and devices of each carbody to satisfy the impact acceleration regulations of the safety regulations. These results will be used as the crashworthy design guidelines for the high speed train in the next year research.

• Journal of the Optical Society of Korea
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• v.20 no.3
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• pp.396-400
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• 2016

Laser speckle patterns were used to monitor variations of thermal voltages of a cathode during a battery discharge. Discharge voltages measured with an oscilloscope were utilized as a figure of merit of thermal voltages in Zn metal. Using an optical imaging system, speckle patterns were taken for zinc metal surface over a time period of 3 minutes. Pixel sum distribution functions (PSDFs) were extracted from speckle patterns. Accumulated pixel sums quantified from PSDFs over an optimized grayscale range strongly correlated with discharge voltages. This suggested that dark matter or particles may have the capability of both absorbing and radiating thermal energies simultaneously. The black body-like properties were able to be validated by identifying coincidences with distinct features of a black body spectrum. The pixels belonging to the grayscale range were confirmed to represent dark matter of a speckle pattern. It was clear that dark matter was part of surface plasmon carriers. The proposed sensing system can be applied to monitor thermal energy variations in any material.

• Solar Energy
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• v.5 no.2
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• pp.60-69
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• 1985

A low cost batch type solar heaters (capacity 200 litres) comprising horizontal tanks, which performs the dual function of absorbing heat and storing the heated water, have been designed and fabricated for the purpose of side-by-side testing. Experimental results have indicated that the sufficient hot water can be obtained in the early morning if the glazing is aided by a reflector/insulation cover. The water heater with best thermal performance such as type B supplied water at a maximum mean temperature of $46-49^{\circ}C$ in the summer afternoon and the temperature of $36-39^{\circ}C$ can be obtained in the early morning if insulation cover is used during night time. The equation has been developed for the prediction of hourly variation of the water temperature in the tank.