• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.151-154
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• 2002

The durability of two kinds of CFRP plates, carbon/UP and carbon/V, was studied under severe environmental conditions. Immersion into the chemical solutions and accelerated weathering were executed on the CFRP plates and the weight change under each condition was measured. After those treatments, the plates were tested by tensile testing machine to measure the mechanical properties and observed by SEM to find the damage behaviour of the surface. Comparing the virgin plates and the chemically exposed plates, both plates show severe deterioration of the mechanical properties. But, the plates subjected to alkali solution show much larger reduction than those of acidic solution and carbon/V has better chemical resistance than carbon/UP. The material properties of CFRP plate exposed to the weathering were deteriorated linearly proportional to the exposure time.

• Korean Journal of Veterinary Research
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• v.48 no.4
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• pp.489-492
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• 2008

An 8-year-old male mynah (Gracula spp.) was presented for depression, anorexia, and respiratory distress. The patient's diet consisted of sponge cake and yogurt alone. Physical examination revealed high body condition score (4/5), abdominal distention, and severe orthopnea. Hepatomegaly was observed on abdominal radiographs. The patient died 4 h after presentation, and severe hepatomegaly was observed at necropsy. Based on histopathological findings, the bird was definitively diagnosed with iron storage disease with concurrent hepatic lipidosis.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.3
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• pp.37-43
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• 2004

Engine lubrication system is generally affected by vehicle driving conditions; acceleration, braking deceleration, and cornering. The oil supply system such as oil pan, baffle plate, and oil pick-up pipe should be optimized to cope with severe driving conditions. The main purpose of this paper is to understand the effect of the engine tilting angle on the oil supply system using engine tilting test rig. For the purpose, the oil pressure fluctuation and oil aeration in the main gallery are measured at various engine tilting angles. In addition, the oil flow is visualized by using transparent oil pan to investigate the cause of the formation of oil aeration. The test results show there is a strong correlation between the main gallery oil pressure fluctuation and oil aeration. It is also found that the visualization technique is helpful to stabilize the oil supply system at severe driving conditions.

• The Korean Journal of Pain
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• v.3 no.2
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• pp.160-164
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• 1990

Herpes Zoster Ophthalmicus comprises 7% of all herpes zoster infection, 50% of those involving eyeballs, and is one disease entitiy with a very grave prognosis. We have experienced a 68-year-old man who visited the emergency room complaining of severe pain in his eye and headache with loss of vision. He was seen by neurosurgeons, dermatologists and ophthalmologists, and finally sent to the pain clinic for control of pain under the diagnosis of herpes zoster ophthalmicus. In spite of zealous treatment efforts, loss of vision, pain and infectious condition did not recover; and furthermore, due to severe infection, he had his eyeball extracted 100 days after the onset of diseases. 140 days after onset, contralateral hemiplegia accompanied the disease process. We present an unusual case of herpes zoster ophthalmicus with no treatment effect.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.24 no.1
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• pp.189-193
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• 1994

Fibrous dysplasia is a benign fibro-osseous condition that is replacement of normal bone and marrow tissues by cellular fibrous tissue and immature bone, and it is divided into monostotic type and polyostotic type. Polyostotic fibrous dysplasia involves multiple bones, such as skull, jaw bones, femur and tibia. And it is also divided into two forms: the less severe Jaffe's type and the more severe Albright's syndrome. Clinically, it frequently occurs in the 2nd decade, and occurs more frequently in maxilla than in mandible. And the lesions of fibrous dysplasia tend to become static as skeletal maturity is reached. The authors experienced three cases of polyostosic fibrous dysplasia in the craniofacial area with the complaints of facial asymmetry due to painless swelling. And we discussed the clinical, radiological, and histopathological features of these cases with a brief review of the literatures.

• Journal of Industrial Technology
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• v.24 no.B
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• pp.83-87
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• 2004

A reduced structure model of a wind turbine generator is designed and manufactured. Mode data are obtained by modal testing and analytical method. Vibration response is measured and investigated under various speed condition by using a waterfall plot. Possibility of severe resonance is observed and the mechanism is explained by using the mode data. Simplified theoretical model gives the 1st resonance frequency of wind turbine structure model. The theoretical model can be applied in the design stage of the wind turbine structure to avoid the severe resonance problem.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.285-287
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• 2006

Ultra-fine grained and high hardened Al sheet was obtained by Equal channel angular pressing (ECAP). During this process the microstructure, the hardness and the texture of AA 1050 Al alloy sheet are changed by a severe shear deformation. The plastic strain ratio after the ECAP and subsequent heat-treatment condition has been investigated in this study. It was found that the average r-value of the ECAPed and subsequent heat-treated specimen was 1.7 times higher than those of the initial Al sheet. This could be attributed to the various texture formations through the ECAP and subsequent heat-treatment of AA 1050 Aluminum alloy sheet.

• Journal of the Korean Ceramic Society
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• v.33 no.3
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• pp.277-284
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• 1996

The water test results indicated that the impurities had detrimetal effect on the wear resistance of silicon nitride and the effects were getting severe as the temperature increased. Especially when Ca existed as an impurity the detrimental effects was the most severe. These results were resulted from the fact that impurities lowered the mechanical properties of the grain boundary phase of silicon nitride. The wear test results of glass/glass-ceramic specimens having a similar composition to the grain boundary phase of silicon nitride revea-led that the specimen containing CaO showed the lowest wear resistance. The existence of Fe and Ca at the grain boundary phase assisted forming a grain boundary phase with relatively low refractoriness. Therefore at a given wear condition the removal of deformed layer would be easier. The results showed that the glass phases could be modified by heat-treatment and this modification improved tribological characteristics of the silicon nitride.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.35-38
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• 2003

We propose a switched beamforming to improve the reception performance of VSB system in severe Rayleigh fading channel. The VSB system has only about 3% of known training signal for the receiver in a data field and the reception performance of VSB receiver is degraded significantly when there are near-0 dB ghosts in receiving signal. The switched beamforming forms several beams in different directions and selects only one beam among them. For the selection of a beam with best channel condition for VSB equalizer, we extracted the channel profiles in time domain for all the beams by correlating the PN511 sequence in VSB field sync and selected optimal beam by comparing the channel profiles. The simulation results show that the proposed method improves the reception performance of VSB system in severe Rayleigh channel.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.427-433
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• 2005

Railway wheelset is the most essential part which undergoes severe cyclic loadings. In recent years, there has been increasing need for insuring the safety of running as the speed of the railway vehicles is getting higher. So it is required on the assessment of fatigue characteristics of the wheelset to consider plastic deformation which might be probable in the severe loading condition. In this study, total-strain controlled low cycle fatigue(LCF) test were performed to observe the LCF behaviors of the railway wheels and axles using companion specimens method. From the experimental results, the cyclic mechanical properties have been evaluated and total strain amplitude versus life relationship have been derived using the empirical Coffin-Manson law.