• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 추계학술대회 논문집
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• pp.358-369
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• 2001

KTX will be operated on Kyun-Pu High Speed Railroad Line around end of 2,003 and KHST(G7 Korea High Speed Train) will be carried out the development running test at Kyun-Pu High Speed Railroad Line from middle of 2002. By the way, the conventional Ho-Nam railroad line was passed the limit capacity of transportation at some area from 1997. For solving of this matter, Ho-Nam railroad line need new high speed railroad line for high transportation capacity of passengers now. This report was studied about the rolling stock system design used new technology of KHST and KTX for Ho-Nam High Speed Railroad.

• 오토저널
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• 제10권1호
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• pp.33-41
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• 1988

A turning (facing) test on Glass Fiber Reinforced Plastics was performed with several tool materials, e.g., cemented carbides, cermet and ceramic, and the wear patterns and wear rate were analyzed to clarify the relation between physical(mechanical) properties and flank wear of cutting tool. The main results are obtained as follows: (1) When cutting speed is increased, the flank wear in every tool material grows the abnormal wear in the shape of triangle at a certain speed, i.e., a critical speed. (2) When cutting speed is increased, the wear rate in experimental tool material starts to increase remarkably at a critical speed. (3) The thermal conductivity among the properties of the tool material and the thermal crack coefficient of it are almost in proportion to the critical speed. (4) The order of performance in tool materials for cutting GFRP is K 10, M10, P20, TiC, CB.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1154-1159
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• 2008

Type of the high-speed train under development has been decided to be EMU(electric multiple Units) following the trend of the times, which is weak for vibration and noise due to the distributed traction unit of motors and gears than that of the articulated high-speed train. Also, passengers may feel uncomfortable at high-speed running due to the various vibration of vehicle itself and bogie, especially due to hunting, snake motion of the high-speed train. In this paper, explained was the program to develop the high-speed EMU at every step of basic and detail design and running test, predict and try to reduce the vibration.

• International Journal of Fluid Machinery and Systems
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• 제8권3호
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• pp.155-168
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• 2015

No-load speed is an important performance factor for the safe operation of hydropower systems. In turbine design, the manufacturers must conduct several model tests to calculate the accurate value of no-load speed for the complete range of operating conditions, which are expensive and time-consuming. The present study presents steady and unsteady methods for calculating no-load speed of a Francis turbine. The steady simulations are implemented using a commercial flow solver and an iterative algorithm that relies on a smooth relation between turbine torque and speed factor. The unsteady method uses unsteady RANS simulations that have been integrated with a user subroutine to compute and return the value of runner speed, time step and friction torque. The main goal of this research is to evaluate and compare the two methods by calculating turbine dynamic parameters for three test cases consisting of high and medium head Francis turbines. Overall, the numerical results agreed well with experimental data. The unsteady method provided more accurate results in the opening angle range from 20 to 26 degrees. Nevertheless, the steady results showed more consistency than unsteady results for the three different test cases at different operating conditions.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.700-705
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• 2003

The object of this study is to ensure the stability of flat freight cars using vibration performance test and static load test of body structures. We examined the flat car though static load test and dynamic characteristics analysis related traveling stability and vibration performance. In the results of static load test of body structures for flat car, all structures satisfied allowable stress of materials. The vibration performance test was satisfied with allowable standards. Although flat car exceed speed a little at some speed interval, it was estimated that the cause was not cars but rail.

• 항공우주시스템공학회지
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• 제7권4호
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• pp.49-54
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• 2013

A turbopump for a 75 ton class liquid rocket engine was tested at full speed for 20 seconds using model fluid. Liquid nitrogen is used for the oxidizer pump, water for the fuel pump, and hot gas for the turbine. The non-cavitating head of pump from the turbopump assembly test showed a good agreement with that from the pump component test. The relative difference of turbine efficiency between the turbopump assembly test and the turbine component test was 0.3% only. Suction performance from the turbopump assembly test was higher than that of pump component test, which resulted from the thermodynamic effect of cavitation.

• 한국자동차공학회논문집
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• 제11권6호
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• pp.14-20
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• 2003

The minimization of valve and seat insert wear is a critical factor in the pursuit of engine performance improvement. In order to achieve this goal, we have developed a new simulator, which can generate and control high temperatures up to $900^{\circ}C$ and various speeds up to 80Hz during motion, just like an actual engine. The wear simulator is considered to be a valid simulation of the engine valve and seat insert wear process with various speeds during engine activity. The objective of this work focuses on the different degrees of wear from two different test speeds (10Hz & 25Hz). For this study, the temperature of the outer surface of the seat insert was controlled at $350^{\circ}C$, the cycle number was 2.1$\times$106, and the test load was 1960N. The wear depth and surface roughness were measured before and after the testing using a confocal laser scanner. It was found that a higher speed (25Hz) causes more wear than a lower speed (10Hz) under identical test conditions (temperature, cycle number and test load). In the wear mechanism adhesive wear, shear strain and abrasive wear could be observed.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.33.2-33.2
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• 2011

The 'NREL Phase VI' model with a 10.06m diameter was tested in the NASA Ames tunnel to make a reference data of the computational models. The test was conducted at the one rotational speed, blade tip speed 38m/s and the Reynolds number of the sectional airfoils in that test was around 1E6. The 1/5 scale down model of the 'NREL Phase VI' model was used in this paper to study the power characteristics in low Reynolds number region, 0.1E6 ~ 0.4E6 which is achievable range for the conventional wind tunnel facilities. The torque generated by the blade was directly measured by using the torque sensor installed in the rotating axis for a given wind speed and rotational speed. The power characteristics below the stall condition, lambda > 4, was presented in this paper. The power coefficient is very low in the condition below the Re. 0.2E6 and rapidly increases as the Re. increases. And it still increases but the variation is not so big in the condition above the Re. 0.3E6. This results shows that to study the performance of the wind turbine blade by using the scaled down model, the Re. should be larger than the 0.3E6.

• 대한전자공학회논문지SD
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• 제45권9호
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• pp.33-40
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• 2008

메모리의 속도가 빠르게 향상됨에 따라, 고속 메모리를 테스트하기 위한 테스트 장비가 요구되고 있다. 특히 고속 메모리를 사용자가 원하는 명령어를 그대로 사용하여 효율적으로 테스트할 수 있도록 패턴을 만들어 내는 알고리즘 패턴 생성기(ALPG)가 필요하다. 본 논문에서는 고속 메모리 테스트를 위한 새로운 병렬 ALPG를 제안한다. 제안하는 ALPG는 명령어 분석기를 통해 사용자가 실행하고자 하는 명령어를 그대로 사용하여 고속 메모리 테스트를 위한 패턴을 생성할 수 있다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.652-657
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• 2004

Korean High Speed Train (KHST) designed to operate at 350km/h has been tested on KyungBu high speed line since it was developed in 2002. The specification of the interior noise level for high speed train in Korea has been adopted through the contract between KHRC and Korea TGV consortium, not a national specification. But it can not be adopted to KHST designed at 350km/h because this has involved up to 300Km/h. Therefor, in this paper, the interior noise level at 350km/h are predicted in passenger car using the results at 300Km/h and these results show that the KHST's interior noise levels are good up to 300Km/h but need to be reduced at 350Km/h in the view point of limit value at 300Km/h of the contract between KHRC and Korea TGV consortium. Also it proposed to make a national specification for the interior noise level to evaluate it in detail at 350Km/h.