• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.279-282
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• 2000

We have been designed and fabricated a bi-directional ultrasonic linear motor using piezoelectric ceramics. With the finite element method, we design and verify validity of the structure, and determine its optimal structure, size of design variables, material and boundary conditions for proper generation of the ultrasonic waves. Based on the design, a prototype of the ultrasonic linear motor has been fabricated and characterized, which thereby proves practical applicability of this new motor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.156-156
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• 2010

We have developed highly efficient blue phosphorescent organic light-emitting devices (OLED) with simplified architectures using blue phosphorescent material. The basis device structure of the blue PHOLED was anode / emitting layer (EML) / electron transport layer (ETL) / cathode. The dopant was partially doped into the host layer for investigating recombination zone, current efficiency, and emission characteristics of the blue PHOLEDs.

• Proceedings of the Optical Society of Korea Conference
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• 2004.07a
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• pp.172-173
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• 2004

Recently there has been many understood the basis device physics OLEDs and their basic operating principle. We demonstrate that there have many relation in order to improve luminescence efficiency both emitting light material physics characteristics and luminary. Efficient Electro Luminescence from organic materials was first reported in 1987 at Kodak. OLEDs emitting light material use tris-(8-hydroxyquinoline)(Alq3). Sudied maximum luminescence efficiency about structure of optimized emitting light layer of OLED which do observing change of luminescence efficiency by structure change of organic material in this paper.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.437-446
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• 1999

The structural behavior of the composite material light rail vehicle body are investigated. Composite material is very useful for light rail vehicle structure due to its high specific strength and lightweight characteristics. The main carbody is made of aluminum alloy. The side wall and roof with composite panels can reduce total vehicle weight about 2000kg. In addition, with the lower density of the foam, enhances lightness in the panel and to save the operation expenses. The finite element analysis code, ANSYS is used to evaluate the stability of the body structure under the various load conditions.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.11
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• pp.906-909
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• 2012

The address discharge characteristics of a open dielectric structure compared with the conventional panel structure are investigated by measuring the discharge firing voltage. The open dielectric structure could easily produce the discharge between the scan and the sustain electrodes by erasing the dielectric layer between two electrodes. Due to the changes in the discharge firing characteristics of the open dielectric structure between the two sustain electrodes, the conventional reset waveform including the address waveform needs to be modified. The modified driving waveform suitable for the open dielectric structure is proposed and examined in AC PDP.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.649-653
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• 2005

Recently, many membrane structure buildings are constructed with the trend of multi functional and high technological construction. The membrane structure has the characteristics such as distinguished architectural shape which can make variable space creation and can make economic use of material. Therefore, it is in the spotlight of sport complex, various concert hall, and public service buildings. However, the acoustic study of membrane structure has not been following up the increasing demand for the membrane structure. In this study, the acoustic characteristics of membrane structure will be studied and analyzed using architectural acoustic factors based on acoustic design theory And also, the differences between theoretical exhortation value and outcome of study will be studied with the basis of architectural acoustic material study.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.878-881
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• 2001

In this paper, we analyzed the characteristics of insulating material with ELB(earth leakage circuit breaker) through tracking experiment and the study was carried out three different types of samples. The tracking is breakdown phenomenon of material surface that is generated on the organic insulating material. The test method applied IEC publication 587. The result of the sample breakdown by tracking was carbonized and resistance of between the electrodes is approximately 300$\Omega$. In the result of DSC analysis, the caloric peak was detected before 100$^{\circ}C$ in product of tracking. It appeared weight loss of 10.87% at 537$^{\circ}C$ on TGA. IR spectrum analysis showed carbon-hydrogen(C-H)bond on molecular structure that is the sample of tracking.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.601-602
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• 2006

The primary role of MRP(Material Requirement Planning) is to make a production plan so that we have an exact quantity of right materials on needed time at right place. But the ignorance on capacity constraints makes some problems whenever production schedule is established. To increase the performance of MRP system, a novel approach which is based on new input data structure is suggested. The new input data structure includes all the information about Material BOM, Routing and resource data so that we can easily examine the usage of resources and generate higher performance production plans.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.994-998
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• 2004

Hybrid method is used to suppress vibration of an automotive roof surface. The hybrid method proposed in this paper is implemented experimentally using both viscoelastic and piezoelectric material. The piezoelectric material is used to control the vibration of automotive structure for lower range of frequencies and the experiment of vibration control using viscoelastic material has been carried out suppress vibrations of high frequency range mark. At first the plate controlled by using hybrid method has been .implemented to verify the performance for suppressing vibration. Then the experiment has been applied to the automotive roof structure.

• Journal of the Korean Geosynthetics Society
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• v.21 no.3
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• pp.1-10
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• 2022

In this paper, the spatial randomness and probability characteristics of material properties are inversely estimated by using a set of the stochastic fields for the material properties of geotechnical structures. By using the probability distribution and probability characteristics of these estimated material properties, topology optimization is performed on structure shape, and the results are compared with the existing deterministic topology optimization results. A set of stochastic fields for material properties is generated, and the spatial randomness of material properties in each field is simulated. The probability distribution and probability characteristics of actual material properties are estimated using the partial values of material properties in each stochastic field. The probability characteristics of the estimated actual material properties are compared with those of the stochastic field set. Also, response variability of the ground structure having a modulus of elasticity with randomness is compared with response variability of the ground structure having a modulus of elasticity without randomness. Therefore, the quantified stochastic topology optimization result can be obtained with considering the spatial randomness of actual material properties.