• Proceedings of the KSR Conference
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• 2009.05b
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• pp.183-188
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• 2009

The High speed electrical multiple train having a distributed electrical motor system has just been developing to aim the experimental maximum speed at 400km/h since August, 2007. This project comes in stage of basic design and so, it needs to take some review and analysis the characteristics of suspensions on the view of basic design. The vehicle model for dynamic analysis is made from the concept design model that used for the preliminary design review with Vampire program and it is modeled with three linear secondary dampers and two shear springs separated from the bush elements in previous model. The optimization technique is applied to search the proper range of linear characteristics for the suspension elements to satisfy the stability performance at speed 130m/s (about 460km/h). The results shows there are some optimum points according to the variation of primary and secondary suspension characteristics and it would be useful to make a decision to select the proper suspension elements in the precision design that will be done by the manufacturing company.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.421-428
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• 1998

Sensitivity analysis of suspension elements of an articulated bogie for light railway vehicles is presented. The ride, stability and safety are used as dynamic performance index. Suspension elements of 10 and a conicity of wheel are used as design variables, To analyze sensitivity of design variables, the railway vehicle dynamics analysis program AGEM is used. The results shows that the secondary suspension elements have a strong effect on ride and the primary suspension elements have a moderate effect on ride. Conicity of wheel has a strong effect on the stability, The safety is not effected by all the design variables.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.248-253
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• 2013

The maximum speed is one of the most important performance in high speed railway vehicle. The higher the train speed is, the worse the ride comfort is, In order to solve this problem, a semi-active or active suspension can be applied to high speed railway vehicle. The variable damper with hydraulic solenoid valve is used in the semi-active suspension. But the variable damper with hydraulic solenoid valve requires tank for supplying fluid. The MR(Magneto Rheological) damper can be considered instead of hydraulic variable damper which needs additional device, i.e. reserver tank for fluid. In the case of active suspension, hydraulic actuator or electro-mechanical one is used to suppress the carbody vibration in railway vehicle. In this study the MR damper and electro-mechanical actuator was considered in secondary suspension system of high speed railway vehicle. The dynamic analysis was performed by using 10-DOF dynamic equations of railway vehicle. The performance of the semi-active suspension and active suspension system were reviewed by using MATLAB/Simulink S/W. The vibration suppression effect of semi-active and active suspension system were investigated experimentally by using 1/5-scaled railway vehicle model.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1575-1580
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• 2009

Maglev vehicle has two kinds of suspension system such as a secondary suspension with air-spring and a primary suspension as electromagnetic suspension which composed of electromagnet, magnet driver, controller and sensors. The interaction between each dynamic component of vehicle and track effects the stability and running performance. To achieve the specified performance of vehicle, many various approaches of research were tried, then as the result of these efforts, the first commercial operating with Maglev will start soon. The bogie for revenue service from 2012 has some significant modifications compared to the previous one, and to verify the changes the half prototype vehicle was manufactured and took the running performance test. In this report, we will introduce the stage of manufacturing and report results of dynamic performance tests to verify new concept of bogie mechanism.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.216-221
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• 2004

The performance of secondary suspension is one of the most important characteristics of railway vehicles in the regard of vibration and riding comfort. For this reason, the suspension shall be designed to absorb vibration energy effectively and to avoid the resonance which would be occurred by the vibration of the bogies in driving. The main factor of characteristics of suspension is spring coefficient of air spring, and this paper shows how to achieve the desired coefficient and the results of the tests of new air springs.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.34-36
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• 2005

In this paper, dynamic simulation results for magnetically-levitated vehicles are presented. The dynamic equations and models for a half-bogie system are derived. They include primary suspension system, module, secondary suspension and cabin. Also, the dynamic characteristics for the derived models are analysed.

• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.909-914
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• 2009

A suspension is the most prior apparatus to decide vehicle's running safety and ride comfort, also the suspension stiffness is the most important parameter for the designing of the vehicle. Providing the strong stiffness with the primary suspension in order to improve the running safety with high speed, but it causes a problem with a curve running performance of a railway vehicle. Therefore, many studies deal with the optimal value of suspension stiffness. In this paper, we aim to optimize the suspension system to improve running safety by varying stiffness values of railway vehicle suspension. We have proceeded an analysis by design variables which are position, length, width, stiffness and damping coefficients of primary and secondary suspension to optimize the suspension characteristics. As a result of the optimization, we verified that the derailment coefficients of inside and outside of wheel are decreased in comparison with initial model.

• Journal of Korean Society of Forest Science
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• v.78 no.2
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• pp.198-208
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• 1989

Cell suspension cultures for Salix koreensis was well established at the supplements of 2, 4-D with cytokinin particulary the combination of 1.0 mg/l 2, 4-D with 0.1 mg/l of zeatin. These combined rates of phytohormones are also effective to callus induction from S, koreensis leaf and its multiplication. Cultured media exhibited the great inhibitory effect on the germination of rice, barnyard grass and lettuce seeds, indicating the presence of biologically active substances in media. Several phenolic compounds such as pyrogallol, sinapic acid, cinnamic acid, tannic + gallic and p-chlorobenzoic acid were detected in the cell suspension culture. The inhibitory effect exhibited by cultured media may be partly attributed to these phenalic compounds.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2003.04a
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• pp.189-189
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• 2003

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.547-557
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• 2020

In this study, damping control devices were applied to the suspension system of a capsule train, and the effects were investigated to improve the ride comfort. The superconductor electrodynamic suspension (SC-EDS) method is used for the capsule train levitation. This method has advantages such as no gap control and a large gap. However, the SC-EDS method has disadvantages such as large gap variation and small damping characteristics against outer vibration, which causes degradation of the ride comfort. In this study, the damping control devices in the primary and secondary suspension were considered to improve the ride comfort in the capsule train. Damping control devices in the primary and secondary suspension can reduce the vibration transmission from outer disturbances to the bogie and from the bogie to the car body, respectively. Simulations for dynamic characteristics analyses were conducted based on the capsule train dynamic model to investigate the effects of the damping control devices on the ride comfort. As a result, it was confirmed that the ride comfort requirements according to the ISO standard can be satisfied by applying the damping control in the capsule train suspension.