• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2498-2504
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• 2009

This paper compared the output limit value of the Korean weak electric field strength wireless device in the 8.2MHz band with the standard values of foreign countries. Through this, the study confirmed that the Korean regulation was lower by about 10-20dB than those of the USA or Europe. In order to prove this, the study measured outputs by entrusting the 8.2MHz EAS system to two measuring companies. As a result of these measurements, electric field strengths were shown to be $70.6dB{\mu}V/m$ and $68.3dB{\mu}V/m$ respectively, and these values were confirmed to exceed the current Korean standard of $59.8dB{\mu}V/m$. Accordingly, it is deemed necessary to review the specifications of the Korean standard in the 8.2MHz band.

• Korean Journal of Materials Research
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• v.19 no.7
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• pp.349-355
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• 2009

Metal thin film patterns on a LTCC substrate, which was connected through inner via and metal paste for electrical signals, were formed by a screen printing process that used electric paste, such as silver and copper, in a conventional method. This method brought about many problems, such as non uniform thickness in printing, large line spaces, and non-clearance. As a result of these problems, it was very difficult to perform fine and high resolution for high frequency signals. In this study, the electric signal patterns were formed with the sputtered metal thin films (Ti, Cu) on an LTCC substrate that was coated with protective oxide layers, such as $TiO_2$ and $SiO_2$. These electric signal patterns' morphology, surface bonding strength, and effect on electro plating were also investigated. After putting a sold ball on the sputtered metal thin films, their adhesion strength on the LTCC substrate was also evaluated. The protective oxide layers were found to play important roles in creating a strong design for electric components and integrating circuit modules in high frequency ranges.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2319-2325
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• 2009

This paper compared the output limits value of the Korean weak electric field strength wireless device in the 58kHz band with the standard values of foreign countries. Through this, the study confirmed that the Korean regulation was lower by about 50dB than those of the USA or Europe. In order to prove this, the study measured outputs by entrusting the 58kHz EAS system to two measuring companies. As a result of these measurements, electric field strengths were shown to be $112dB{\mu}V/m$ and $08dB{\mu}V/m$ respectively, and these values were confirmed to exceed the current Korean standard of $102.7dB{\mu}V/m$. Accordingly, it is deemed necessary to review the specifications of the Korean standard in the 58kHz band.

• New Physics: Sae Mulli
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• v.68 no.11
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• pp.1183-1191
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• 2018

The plasmon behaviors in a superlattice of $GaAs/Al_xGa_{1-x}As$ multiple quantum wells with a half-parabolic confining potential due to different dielectric interfaces are studied under magnetic and electric fields perpendicular and parallel to the superlattice axis by using a previously published theoretical framework. From the density-density correlation functions by considering the intrasubband and the inter-subband transitions under the random phase approximation, we calculate the dispersion energies of the surface and the bulk states as functions of the composition of the multiple quantum well structure and of the magnetic field strength and the average electric field strength over the quantum well. The Raman intensities for various magnetic field strengths and average electric field strengths over the quantum well are also obtained as a function of the energy of the incoming light for these states.

• Journal of the Korean Geotechnical Society
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• v.25 no.4
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• pp.39-54
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• 2009

Large scale direct shear tests were carried out to analyze the shear behavior of crushed rocks at local representative quarries. Shear strength for each specimen was derived and the effects on shear behavior induced by the variation of factors such as particle size, water immersion, density, uniformity coefficient, and particle breakage were evaluated and quantitatively compared with previous studies. The opportunity was also taken to identify stress-dilatancy relation of crushed rocks following the energy-based theory and friction coefficients at critical state as well as peak friction angles and dilation angles were estimated. As a result of tests it was found that uniaxial compressive strength and particle breakage of the parent rocks have crucial effect on internal friction angles; in addition, dilatancy at the failure showed strong relationship as well.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.450-451
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• 2006

The method of conductor wiring is that a messenger wire is installed, the end of the wire is connected to the conductor and a engine puller pulls the conductor. The length of one section of wiring is $3{\sim}5km$ and one group messenger wire pulls simultaneously $2{\sim}4$ group conductor, while a tensioner maintains wiring tension to prevent the deflection of the conductor. However, there are many obstacles such as roads, power lines, communication lines, buildings, farms and crops. Therefore to prevent damage from conductor deflection a staging is used. The currently used staging is scaffolding lumber which is difficult to secure and it's construction efficiency is very low because it requires a lot of time and manpower. So this study developed a insulating defense tube and pipe connecting device, and a truss structure fabrication module using steel pipe which reduces construction time and cost through a compressive and dielectric strength test.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.260-260
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• 2010

In recent years, polymer/clay nanocomposites have generated a great interest, both in industry and in academia, because they often exhibit remarkable improvement in material properties when compared with the virgin polymer or conventional micro and macro-composites. Among these properties are stiffness, strength, dimensional stability and permeability. [1-3] The dispersion of hydrophilic silicates in a hydrophobic matrix like Polyethylene (PE) is difficult because of the difference in character between PE and Montmorillonite (MMT). Therefore, it is necessary to modify PE with polar groups, which can increase the hydrophilicity of PE. In this study, High density polyethylene (HDPE)/$Mg(OH)_2$/Montmorillonite (MMT) nanocomposites having a various compositions were prepared by a melt blending technique with an internal mixer and properties namely mechanical, morpology, rheological and thermal properties were investigated

• International Commerce and Information Review
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• v.10 no.4
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• pp.277-298
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• 2008

This study develops the market attractiveness assessment model and draws the strategic target markets and their corresponding exporting strategies through identifying the market positions in the dimensions of market attractiveness scores and market positional strength to achieve the innovative export promotion of Korean heavy electric industry and the resulting improvement and reversal of comparative-disadvantage position. In chapter 2, we analyze the stages of selecting target markets, the constructs and their measure variables of market attractiveness models, and the components and strategic policy implications of directional policy matrix. And in chapter 3, we identify the comparative advantage positions of Korean heavy electric industry in the global market through analyzing its trade structure, trends, balance, ratio-balance, and specialization index by the item and the region respectively. We find that the Asia/Pacific region is the most attractive export market of the Korean heavy electric equipment industry, the following important strategic target markets are the America, MENA, CIS/East Europe Regions in the order of their attractiveness and competitive position dimensions. In the mean time, the sub-Sahara Africa and West Europe region is shown to be the long-run-viewpoint target market requiring the innovation or divest strategies owing to their low attractiveness and the low market share of Korean exports.

• Journal of the Korean Ceramic Society
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• v.43 no.12 s.295
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• pp.775-780
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• 2006

Mechanical and electrical performance of anode-supported SOFC single cells were analyzed after thermal cyclic operation. The experiments of thermal cyclic cell-operation were carried out four times and performance of each cell was measured at different temperatures of 650, 700, and $750^{\circ}C$, respectively. As increasing the number of thermal cycle test, single cells showed poor I-V characteristics and lower 4-point bending strength. The anode polarization was also measured by AC-impedance analysis. The observation of the microstructure of the anodes in single cells proved that the average particle size of Ni decreased and the porosity of anode increased. It is thought that the thermal cycle caused the degradation of performance of single cells by reducing the density of three-phase boundary region.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.2
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• pp.130-136
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• 2018

This study develops a seat with electric motor technology for a one-ton grade commercial vehicle. While applying electric motor technology, the FMVSS 210 seat frame strength test is also conducted to examine the product's weak parts. The seat frame strength test used the FMVSS 210 test standard and the ANSYS program was used to simulate the test and identify weak parts in the deformation and strain values. The test results showed that the cushion frame and slide rail connection bracket were fractured at loads of about 10,000 N. Similarly, the maximum stress and strain values in the bracket were obtained in the simulation results. On this basis, it was evaluated that the connection part bracket was a considerably weak part in the case of the first model, and changing the shape of the bracket and reinforcing the strength were required. In addition, the seat belt anchorage test results and simulation results were compared to assure their validity. In the comparison results, the error for each is about 5-10%. Therefore, the simulation performed in this study is considered to have produced reasonably accurate results.