• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.876-879
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• 1996

The vibration of an attractive magnetic levitation(Maglev) vehicle transportation system is caused by the irregularity of the guideway track and the performance of the suspensions of the Maglev system. It is essential for us to give attention to the secondary suspension of the vehicle system as it determines the ride quality. In order to improve the ride quality and running stability, active secondary suspensions have been developed and applied to the vibration problems. This paper analyzes the performance of the active secondary suspension which is applied to an attractive magnetic levitation vehicle system running on a rough track. The dynamics of the suspension system and the optimal control problems are studied. According to the transient and frequency response analyses to the track disturbance, the ride quality of an attractive Maglev vehicle has been improved by applying the designed LQR active controller, and it has been confirmed that this improvement was also influenced by the configuration of the system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.854-855
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• 2011

Active suspension technology of railway vehicles has received attention as the way to replace the current passive suspension. This paper deals with the dynamic performance of an active suspension system for a railway vehicle. To verify performance of an active suspension, the dynamic performance of the railway vehicle with active suspension system analyzed and compared with conventional suspension system by using the VI-rail program.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.10
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• pp.1051-1059
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• 2013

In general, lateral ride comfort of railway vehicle is mainly influenced by a secondary suspension placed between the bogie and carbody. Higher operating speeds of train results in increased vibration of carbody, which has a negative impact related to the ride comfort. To solve this problem, researches to replace the conventional passive suspension with (semi)active technology in the secondary suspension of a railway vehicle have been carried out. The semi-active suspension using the magneto-rheological damper is relatively simpler system and has advantage in maintenance compared to the hydraulic type semi-active damper. This study was performed to reduce lateral vibration acceleration of carbody related to ride comfort of railway vehicles with a semi-active suspension system. The numerical analysis was conducted by replacing passive lateral damper with semi-active MR damper, and robust control with the MR damper was applied to the 1/5 scaled railway vehicle model.

• 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 Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.71-76
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• 2010

This paper presents the feasibility for improving the ride quality of railway vehicle equipped with semi-active suspension system using magnetorheological(MR) fluid damper. In order to achieve this goal, a fifteen degree of freedom of railway vehicle model, which includes a car body, bogie frame and wheel-set is proposed to represent lateral, yaw and roll motions. The MR damper system is incorporated with the governing equation of motion of the railway vehicle which includes secondary suspension. To illustrate the effectiveness of the controlled MR dampers on railway vehicle secondary suspension system, the sky-hook control law using the velocity feedback is adopted. Computer simulation for performance evaluation is performed using Matlab. Various control performances are demonstrated under external excitation which is the creep force between wheel and rail.

• 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 KSR Conference
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• 2007.05a
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• pp.1631-1638
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• 2007

In this paper, a modeling for the dynamic behavior of a train vehicle is suggested for the prediction of the braking characteristics. In the dynamic modeling, effects of the primary and secondary suspension elements are considered and interactions between two vehicles are also estimated. This study can offer some fundamental results for a further research to enhance the braking performance using active braking control.

• KSBB Journal
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• v.13 no.3
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• pp.251-258
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• 1998

A structured kinetic model is proposed to describe cell growth and secondary metabolite, flavone glycosides, synthesis in batch suspension culture of Scutellaria baicalensis G. The model has been developed by representing the physiological state of cell described as the activity and viability which can be estimated based on the culture fluorescence. In the model, three type of cells are considered; active-viable, nonactive-viable and dead cells. Viable cell weight could be determined based on the relative fluorescence intensity. The flavone glycosides could be produced by both active-viable and non-active viable cells with a different production rate. And the model includes the cell expansion due to glucose concentration and death phase which accounts for the release of intracellular secondary metabolite into medium. Dependent variables include substrate concentration(glucose), cell mass(dry cell weight and fresh cell weight), product concentration(flavone glycosides), activity and viability. Satisfactory agreement between the model and experimental data is obtained from shake flask culture of Scutellaria baicalensis G. The proposed model can predict the cell growth and flavone glycosides synthesis as well as intermediate materials.

• Journal of the Korean Electrochemical Society
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• v.6 no.2
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• pp.103-112
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• 2003

Various kinds of metals were coated on synthetic graphite in order to investigate the relationship between film characteristics and their electrochemical performance. Gas suspension spray coating method was employed for the coating of synthetic graphite. In our experimental range, all of the metal coated synthetic graphite showed the higher capacity than that of raw material at high C-rate mainly due to decrease in impedance of passivation film. In cyclic voltammetry experiments, silver-coated and tin-coated graphite anodes found the lithium-alloy reaction. Considering smaller amount of metal coating, the most increase in discharge capacity was caused by improvement of conductivity of the electrode. When single-component metal was coated, silver-coated graphite anode exhibited the highest discharge capacity and better cycleability. Double components of silver-nickel coated active material showed the highest discharge capacity, rate capability and the best cycle performance in the range of our experiments.

• Journal of Plant Biotechnology
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• v.3 no.1
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• pp.1-5
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• 2001

Traditional culture technology of medicinal plants mainly depends on the field culture, which has many problems. With progress of modern culture technology, it has become possible to produce valuable secondary metabolites from medicinal plants. In this paper, we discuss about the pigment and saikosaponin production from too medicinal plants, Carthamus tinctorius and Bupleurum falcatum, through bioreactor culture system. A two-stage bioreactor culture system was established for the production of yellow and red pigments and saikosaponins by cell suspension cultures of Carthamus tinctorius and Bupleurum falcatum. In Carthamus tinctorius, balloon type airlift bioreactors and column type airlift bioreactors were employed for the tell culture and for the pigment production, respectively. The greatest pigment production was obtained on White medium supplemented with 4 mg/L kinetin, high levels of sucrose concentration and photosynthetic photon flux. In Bupleurum falcatum, adventitious roots were cultured in balloon type airlift bioreactors and the root growth was greatest on SH medium containing 5 mg/L IBA and 0.2 mg/L kinetin. HPLC analysis showed that the contents of main active saikosaponins a, c, and d in adventitious roots were almost the same as those in field cultured root.