• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.117-124
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• 2018

This paper describes the localization development of an axial fan for KM-SAM multi-function radar. The multi-function radar, which is constantly affected by the external environment, is a key instrument for detecting and tracking low and medium altitude threat targets. Operating this equipment smoothly requires a fan for controlling the internal temperature and humidity. Presently, all such fans are imported. To solve these problems, localization development research was proposed. The development of localization includes analysis of requirements through review of related technical reports such as original equipment and system equipment specification, prototype design, and verification of design requirement through performance test and environmental test. The study results are described. The blower consisted of an axial fan with guide vanes and the motor was designed to generate a maximum airflow of 970 CFM and a wind pressure of 4.8 IWG. Six prototypes were manufactured for performance evaluation. In addition, for reliable data acquisition, AC power supply, fan performance tester and data acquisition equipment were designed and tested. All prototypes were verified as having design requirements equal to or better than those of imports.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1444-1452
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• 2011

At present, Kyungbu high-speed railway is operated with 300km/h, Honam high-speed railway is being constructed with 350km/h, and the development for the overhead contact line system is to be conducted for the next-generation high-speed railway with the speed of 400km/h. It is necessary to set up the specification and criteria for the key parts such as dropper, termination clamp and tension insulator for the 400km/h railway line. In this paper, the specification and the criteria for dropper, termination clamp and tension insulator has been reviewed and proposed in order to secure long-term reliability and stability under the maximum speed of 400km/h. Also, the specification, criteria and international standards for 300km/h class and 350km/h class railway line system and the international standards related with the insulators have been reviewed, compared and analysed.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.428-432
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• 2008

The next Korean high speed train development project is started. In testing stage of this project, the 400km/h maximum speed test will be conducted. In Korean railway infrastructure conditions the 400km/h seems to be a critical speed especially in the aspect of the overhead contact lines. The current collection performance of the 400km/h which is predicted by dynamic interaction simulation are described in this paper. To discuss the permissible criteria of contact forces, displacements and percentage contact loss, the French 575km/h current collection conditions are simulated. Furthermore, review of the simulation results of the Korean 400km/h current collection conditions is conducted through comparison with that of the French 575km/h.

• Progress in Superconductivity and Cryogenics
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• v.22 no.2
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• pp.32-37
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• 2020

Sam Dong Co., Ltd. has been succeeded in producing a 1 km multi-filament conductor in 2018. So far, we become more widespread to fabricate a variety of customized multi-filament wires such as 6 + '1' Cu, 18 + '1' Cu, and 36 + '1' Cu. In this work, we discuss the research progress on various MgB₂ wires over the past three years. We also provide a brief review for applications with our wires.

• Electrical & Electronic Materials
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• v.26 no.7
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• pp.28-34
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• 2013

• The Journal of Korean Medicine
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• v.16 no.1 s.29
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• pp.281-294
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• 1995

The effect of Sam Hwa San on the Na-K-ATPase activity was evaluated in microsomal fraction prepared from rabbit cerebral cortex to determine whether Sam Hwa San affects Na-K-ATPase activity of nervous system. Sam Hwa San markedly inhibited the Na-K-ATPase activity in a dose-dependent manner with an estimated $I_{50}$ of 0.12%. Optimal pH for the Na-K-ATPase activity was at 7.5 in the presence or absence of Sam Hwa San. The degree of inhibition by the drug more increased at acidic and alkalic pHs than neutral pH. Kinetic studies of substrate and cationic activation of the enzyme indicate classic noncompetitive inhibition fashion for ATP, Na and K, showing significant reduction in Vmax without a change in Km. Dithiothreitol, a sulfhydryl reducing reagent, partially protects the inhibition of Na-K-ATPase activity by Sam Hwa San. Combination of Sam Hwa San and ouabain showed higher inhibition than cumulative inhibition. These results suggest that Sam Hwa San inhibits Na-K-ATPase activity in central nervous system by reacting with, at least a part, sulfhydryl group and ouabain binding site of the enzyme protein, but with different binding site from those of ATP, Na and K.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.201-206
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• 2009

In the testing stage of HEMU-400X(next Korean high speed train) developing project, maximum speed(400km/h) tests will be conducted. On present and near future conditions of the overhead contact lines, 400km/h is over the design speed criteria. The predictions of current collection performance including the percentage loss of contact(arcs level) parameter through dynamic interaction simulation of HEMU-400X maximum speed test run are described in this paper. Various simulations are conducted at the condition of two different contact wire tensions to draw the proper contact wire increasing values in the 400km/h test line under the available contact wire tension supporting condition of that line.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.12
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• pp.1742-1746
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• 2014

In order to develop a overhead catenary system for the maximum speed of 400 km/h on Honam high-speed line, increasing tension of contact wire, changing dropper distributions, reducing a hard point and etc. should be considered. And it is also essential to develop core components taking account of the increased tension. Therefore we developed a new steady arm for the max. speed of 400 km/h in this study. FEM (Finite Elements Method) analysis was performed to ensure the strength of the arm. An oval shape was applied to the arm, so that 25 % of strength was increased and 9 % of weight was decreased. And a type test according to the code KRSA-3012 was performed to ensure the performance. Fatigue test in KRRI (Korea Railroad Research Institute)'s test-bed was also performed to evaluate its performance. Some section of the Honam High-speed line was constructed with the developed steady arm.

• Journal of the Korean Society for Railway
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• v.19 no.3
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• pp.288-296
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• 2016

A 400km/h simple catenary system was constructed as a test line in Korea. In the design stage of this system, the pre-sag was one of the engineering issues most focused on. It is known that the pre-sag improves the current collection performance in a certain band of high speed. However, the effect of pre-sag at 400km/h has not yet been established. To grasp a better pre-sag in the 400km/h catenary, we transacted the dynamic performance prediction simulation between catenary and pantograph under conditions of 0 and 1/3000 pre-sag. The level of 0 pre-sag was adapted for the 400km/h catenary design after reviewing predictions. We constituted the 1/3000 pre-sag sample section (about 1km) while constructing the 400km/h catenary test-bed (28km) of 0 pre-sag. With a HEMU-430X train, the contact forces were measured in the test-bed including the pre-sag sample section. In this paper, the predicted and measured dynamic performance values (contact forces) for 0 and 1/3000 pre-sag are described and compared. It is conclusively confirmed by analytical and experimental examination that the non pre-sag showed better dynamic (current collection) performance than that of the 1/3000 pre-sag for the 400km/h catenary system.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.932-939
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• 2011

This paper deal with technique of tension length calculation for 350km/h high speed catenary system. Tension length affects in facility investment. Possibility of overlap increasing a tension length and the equipment investor decreases in order to decrease. Considers the parameter which specifies and the grudge which is possible long the fact that decides a tension length is the aim which is important plans overhead contact line. The element which decides a tension length with next following; (i) Operating range of tension device, (ii) Change of the horizontal tension which affects possibility of the effect which operates to the line and span, (iii) Tension of wire material the tensile force which is relation, (iv) Wire thermal expantion which relates with a standard temperature, (v) Curve radius, (vi) Wind velocity, (vii) Thermal range of overhead contact wire and mechanical design of tension mechanism etc.