• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.28-31
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• 2003

We have investigated the electrical characteristics of the organic light emitting diodes (OLEDs) using the numerical device simulation. The current-voltage characteristics, the charge carrier concentrations, and the recombination rate profiles are presented. The simulation results of the effects of the various device parameters on the device characteristics are discussed.

• Progress in Superconductivity and Cryogenics
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• v.17 no.1
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• pp.44-47
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• 2015

High voltage superconducting apparatuses have been developed presently around the world under AC and DC sources. In order to improve electrical reliability of superconducting apparatuses with AC and DC networks, a study on the DC as well as the AC electrical breakdown characteristics of cryogenic insulations should be conducted for developing a high voltage superconducting apparatus. Recently, a sub-cooled liquid nitrogen cooling system is known to be promising method for developing a high voltage superconducting apparatus. A sub-cooled liquid nitrogen cooling system uses gaseous nitrogen to control the pressure and enhance the dielectric characteristics. However, the dielectric characteristics of gaseous nitrogen are not enough to satisfy the grade of insulation for a high voltage superconducting apparatus. In this case, the application of solid insulating barriers is regarded as an effective method to reinforce the dielectric characteristics of a high voltage superconducting apparatus. In this paper, it is dealt with a barrier effect on the DC and AC dielectric characteristics of gaseous nitrogen with respect to the position and number of solid insulating barriers. As results, the DC and AC electrical breakdown characteristics by various barrier effects is verified.

• Journal of Ocean Engineering and Technology
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• v.23 no.6
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• pp.17-22
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• 2009

This study presents an investigation of the characteristics of piezoelectric sensors whose main utilization is to measure impact pressure. The piezoelectric sensors were tested from several points of view. Their characteristics were investigated for repeatability, the effect of the diameter, temperature effect, water purity, flush mounting, and AC and DC coupling. Out of these, it was revealed that the temperature effect is very significant. The characteristics of the AC and DC coupling are also very important in understanding the time history of the impact pressure.

• Wind and Structures
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• v.7 no.4
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• pp.281-291
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• 2004

The flutter characteristics of long span bridges are discussed from the point of the unsteady pressure distribution on bridge deck surface during heaving/torsional vibration related to the aerodynamic derivatives. In particular, it is explained that the coupling terms, which consist of $A_1^*$ and $H_3^*$, play a substantial role on the coupled flutter, in comparison with the flutter characteristics of various structural sections. Also the effect of the torsional/heaving frequency ratio of bridge structures on the flutter instability is discussed from the point of the coupling effect between heaving and torsional vibrations.

• International Journal of Fluid Machinery and Systems
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• v.10 no.3
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• pp.307-317
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• 2017

In liquid-propellant rockets, POGO instability can occur, in which a fluctuation of propellant supply to the engine, a thrust fluctuation, and a structural vibration are coupled. For the prediction of this instability, it is required to provide dynamic characteristics of the pump represented as the transfer matrix correlating the upstream and downstream pressure and flow rate fluctuations. In the present study, the flow rate fluctuation is evaluated from the fluctuation of pressure difference at the different locations assuming that the fluctuation is caused by the inertia of the flow rate fluctuation. The experiments were performed in some flow conditions, and it was shown that the tendencies of dynamic characteristics are related to excitation frequencies, cavitation numbers and flow rate coefficients.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1213-1215
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• 1997

In order to investigate the electrical characteristics due to the BTA(Benzotriazole) additive in the transformer, the electrical characteristics of the transformer oils contained benzotriazole as an anti-static agent for streaming electrification is studied by measuring the electric conduction. As a result of the electrical conduction characteristics, it is confirmed that the conduction current of virgin specimen is more higher than that of specimen contained the BT A 10[ppm] over 35[$^{\circ}C$], but that of specimen contained the BT A 10[ppm] over 50[$^{\circ}C$] is increased.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1683-1685
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• 2003

MgO is making an important role not only as a protective layer but also improves the discharge characteristics at AC PDP. Until now, the substitute of protective layer, MgO has been studied in many ways, but it's too difficult to get a new substitute as stable as MgO. But some problems has been advanced at the discharge characteristics of MgO on high temperature. So we studied the discharge characteristics of impure MgO with $SiO_2$ doped.

• Industrial Engineering and Management Systems
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• v.14 no.1
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• pp.88-93
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• 2015

In this paper, we identify the characteristics of modeling and simulation (M&S) for military and defense and propose the method of verification, validation, and accreditation (VV&A) using the identified characteristics. M&S has been widely used for many different applications in military and defense, including training, analysis, and acquisition. Various methods and processes of VV&A have been proposed by researchers and M&S practitioners to guarantee the correctness of M&S. The notion of applying formal credibility assessment in VV&A originated in software engineering reliability testing and the systems engineering development process. However, the VV&A techniques and processes proposed for M&S by the research community have not addressed the characteristics and issues specific to military and defense. We first identify the characteristics and issues of military/defense M&S and then propose techniques and methods for VV&A that are specific for military/defense M&S. Possible approaches for the development of VV&A are also proposed.

• Geomechanics and Engineering
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• v.16 no.3
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• pp.217-231
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• 2018

Clayey soils with swelling and shrinkage characteristics have been major causes for many problems in roads, buildings and other civil engineering infrastructure in various areas of Pakistan, particularly where there are several patches of such soils on either side of Indus River. As the consistency characteristics are directly related with the variation of moisture content; therefore, this study was explicitly focused to investigate the effect of lime and wheat straw on the consistency characteristics of clayey soils with relatively high swelling and shrinkage characteristics. The consistency test results indicate that by the increase in lime content there is a decrease in the plasticity index of soil; for instance, 10% lime content resulted to 59% decrease in the plasticity index value. On the other hand; the addition of wheat straw resulted in a significant increase in the plasticity index; for instance, 10% wheat straw content resulted to a 120% increase in the plasticity index. This study has further shown that the shrinkage and swelling of clayey soils which resulting to several problems in the civil engineering infrastructures may adequately be managed through mixing an appropriate amount of lime and wheat straw as soil stabilizing agent for both immediate and long-term effects.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.1
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• pp.16-22
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• 2018

Silicon carbide (SiC) is used in various semiconductor processes because it has superior thermal, mechanical, and electrical characteristics as well as higher chemical and corrosion resistance than existing materials. Due to these characteristics, various manufacturing technologies have been developed for SiC. A recent development among these technologies is Chemical Vapor Deposition SiC (CVD-SiC). Many studies have been carried out on the processing and manufacturing of CVD-SiC due to its different material characteristics compared to existing materials like RB-SiC or Sintered-SiC. CVD-SiC is physically stable and has excellent chemical and corrosion resistance. However, there is a problem with increasing the thickness, because it is manufactured through a deposition process. Additionally, due to its high strength and hardness, it is difficult to subject to machining.