• Electrical & Electronic Materials
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• v.17 no.5
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• pp.3-12
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• 2004

지난 십년동안 정보산업의 지속적인 고속성장과 맞물려 단파장 광소자와 고출력, 고주파 전자소자의 성능에 대한 사양이 날로 높아 감에 따라 그 어느 때보다 소자 제조 공정에서 고품위 박막 성장이 중요한 위치를 차지하게 되었다. 자연스럽게 연구자들은 이러한 소자에 대한 높은 요구를 충족시키기 위해 기존 발광소재(GaN, 6H-SiC)를 근간으로 소자의 성능을 개선하려는 노력 뿐 아니라 기존 물질의 한계를 극복할 수 있는 새로운 발광소재에 대해 관심을 갖게 되었다.(중략)

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.405-412
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• 1998

Recently“ride comfort”problem becomes increasingly important because of today's needs for train speedup The concept of term “riding comfort” is equivocal. Generally it is defined as the vehicle vibration. There are many studies on evaluation method of ride comfort for railway. But each of then recommends the different assessment method and the different guidance. So users must review whether they can apply it to their system or not. In this paper, we discuss the evaluation methods defined in the standards - ISO 2631, UIC 513 R, CEN DRAFT prENV 12299 and the ride index suggested by Sperling.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.583-588
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• 1998

Large extrusions of aluminium alloy can be more general and useful as structural material of rolling stocks to reduce weight and labor cost than mild steel and stainless steel. Our company is studying aluminium coach body will be made of 6005A and A5083 alloy. In this paper, at first detailed finite element analysis is carried out to calculate the orthotropic material properties of aluminium extrusions. And then global strength evaluation of coach body is carried out according to UIC 566 OR code.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.451-457
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• 2008

The aim of the sturdy is for the development of Bridge plate installing on floor for SETPA Sliver line V. SEPTA train have pocket sliding door which is similar with domestic trains. typically In the USA railway market, Portable type and standing type bridge plate used, easily hiding the bridge plate in stowed position and convenience operation, Bridge plate installed on floor is designed. relative regulation Like CFR APTA, and EN, UIC is reviewed and compared.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.3
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• pp.310-317
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• 2014

The Next-generation High-speed Rail Technology Development Project was started in 2007 by the Korean Government with the aim of developing the core technologies for a high-speed electric multiple unit (EMU) railway system. This is the first attempt to develop a high-speed EMU railway. High-speed EMU trains have superior acceleration and deceleration compared to push-pull high-speed railways such as KTX(Korean Train eXpress). A prototype train was developed and tested on a high-speed line starting in 2012. The new train must maintain running safety during the test. Generally, the international standard (UIC518) is adopted to evaluate the running safety of trains. This method suggests that the test zone must have over 25 sections, and the length of each section must be 500 m. However, it is difficult to implement these test conditions for a real high-speed line. In this study, we analyzed the running safety using several test section lengths (100 m to 500 m) and compared the results. The results of this study will be used to establish a running safety evaluation method for high-speed EMU railways.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.12
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• pp.5669-5675
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• 2012

To reduce the cost and the time of transport in Eurasian railroad networks such as TKR(Trans-Korea Railway), TCR(Trans-China Railway) and TSR(Trans-Siberia Railway) owing to the problem of different track gauges (narrow/standard/broad gauge), it is important to develop the gauge-adjustable wheelset(GAW) system to adapt easily to these gauges. The Korean GAW system is developing and will be adapting to the brand new freight trains' to improve the conventional overseas GAW system. In this study, structural and durability analyses are performed from the viewpoint of the safe-life design. The core parts of the system might be safe in range of $1{\times}10^7$ cycles from the result of durability analysis. Moreover, to examine the safety of the system while running on a track, rig fatigue test was performed according to UIC code. The safety of the Korean GAW system is demonstrated through testing that all safety-relevant conditions are satisfied.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.7
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• pp.827-833
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• 2011

In this study, a simulation model to estimate the current-collection performance of a high-speed train was developed by using a commercial finite element analysis software, SAMCEF. A three-dimensional springDdamperDmass model of a pantograph was created, and its reliability was validated by comparing the receptance of the model to that of the actual pantograph. The wave propagation speed of the catenary model was compared with the analytical wave propagation speed of the catenary system presented in the UIC 799 OR standard. The length of the droppers was controlled, and the pre-sag of the contact wire due to gravity was considered. The catenary and the pantograph were connected by using a contact element, and the contact force variation when the pantograph was moved at velocities of 300 km/h and 370 km/h was obtained. The average, standard deviation, maximum, and minimum values of the contact force were analyzed, and the effectiveness of the developed simulation model was examined.

• Journal of the Korean Society for Railway
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• v.15 no.2
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• pp.141-146
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• 2012

The rail surface defects which are generated on repeated rolling contact fatigue are getting increased according to high speed, high density, and minimum weight. In addition, Increasing noise and vibration are affected by these also impact load generated as well. Because of this phenomenon, more serious and critical damages were occurred. In fact, in order to control them, the rail grinding amount in Korea. This study evaluated how depth of hardening on rail surface is formed and suggested optimal rail grinding amount by RCF(rolling contact fatigue) test with generated contact pressure between KTX wheel and UIC60 rail by applying FEM analysis. Therefore, the amount was generated approximately 0.2mm/20MGT to maintain integrity of rail surface by getting rid of depth of hardening on rail according to rail accumulated passing tonnage.

• Journal of the Korean Society for Railway
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• v.20 no.5
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• pp.577-587
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• 2017

In the design process of dynamic characteristics of a railway vehicle, demand for analysis, testing and estimation methods of running stability are increasing as railway vehicle speed is increasing. Critical speed tests and estimation have been carried out using computer simulation or special test facilities, like roller rigs, because real track testing at critical speed is very dangerous. This paper introduces a test and assessment method for critical speed and estimates the validity using several roller rig tests. The test results show that it is difficult to estimate the critical speed using safety and instability assessment method in UIC 518, but that there is good agreement between the reduction of the equivalent damping ratio and the critical speed.

• Journal of the Korean Society for Railway
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• v.7 no.4
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• pp.332-338
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• 2004

The two projects about the high speed train have been performed in Korea, one project is the commercial run of high speed train(KTX) from Seoul to Busan and the other is the development of original high speed train(HSR 350x). As the successful results, the service run of KTX had been launched on the 1st of April, 2004 and HSR 350x had been fabricated in June, 2002 and has been tested in the Kyoungbu line and Honam line since then. The railway has the track irregularities which cause vibrations, such as rail joints, turnout, level crossing, transition curves and super-elevation ramps, and variations in the track level(z-axis) and the gauge(y-axis). Generally, the ride comfort for railway is evaluated by using the vibrations. In this paper, the ride comfort indices according to mc 513R and ISO 10056 have been reviewed when the high-speed trains are operated on both Kyoungbu line and Honam line. Also, the ride characteristics for KTX and HSR 350x on the high speed line and the conventional line have been analyzed and evaluated. The results show that the high-speed train has no problem from the viewpoint of the comfort ride on the high speed line and the conventional line and the ride index for HSR 350x is same as that for KTX in the high speed(300 km/h).