• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.498-501
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• 2012

The Model Rocket Engine Test Facility has been improved to develop the Korea Space Launch Vehicle II(KSLV-II). The modified Model Rocket Engine Test Facility will be used to develop 7-tonf class liquid rocket engine combustor. The test result and test technique acquired from this facility will be used to develop the high performance liquid rocket engine combustor. This paper describes the modified Model Rocket Engine Test Facility for a Sub-scale model test of the 7-tonf class combustor.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.166-169
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• 2004

This paper describes the design, installation and certification activity of a combustion test facility of subscale thrust chambers propelled by pressure-fed liquid oxygen and kerosene, and suggests major key issues considered at each development stage of the facility

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.55.1-55.1
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• 2011

풍력터빈에 적용되는 제어로직에 대한 검증을 실험실 기반에서 검증하기 위해서는 바람 및 터빈에 대한 적절한 모델링이 선행되어야 한다. 특히 피치 및 토크제어에 대한 특성을 검증하기 위해서는 블레이드 공력특성 및 터빈의 동특성에 대한 반영이 필연적이다. 본 논문에서는 풍력터빈 적용 제어로직 검증을 위하여 대상터빈에 대한 스케일링 결과, 바람을 모사하기 위한 구동장치 동작 및 터빈 모사장치에 대한 설계 결과에 대하여 소개하도록 한다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1011-1015
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• 2017

In this study, numerical and experimental studies on the nozzle flow in a sub-scale cold flow test were conducted to simulate high altitude condition. In the theoretical calculation, the temperature of the nozzle outlet is calculated to be lower than the liquefaction point, and the fluid exists at the phase change point. Also, numerical analysis result is higher than theory calculation but lower than liquefaction temperature. As a result of cold flow test, it was confirmed that the temperature was much higher than theory and analysis. This is because it assumed that it is adiabatic in the theoretical calculation, but the experiment in the actual environment is not the adiabatic but the heat exchange with the outside exists.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.4
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• pp.56-61
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• 2009

This paper presents the ground surface potential profiles and hazard voltages around the metallic structure connected to a small-sized model ground electrode. Because it is very difficult to draw valid conclusions concerning a general grounding problem from actual field data, scale model tests can be used to determine the touch and stop voltages and surface potential profiles around ground electrode. In this work, a hemispherical vessel with a diameter of 1,100[mm] was employed to simulate uniform soil. As a result, the ground surface potential around the ground electrode was significantly raised In particular the ground surface potential at the just upper point of ground rod was higher than other points. When the buried depth of ground rod is increased, the ground surface potential and step voltage were lowered but the touch voltage was elevated.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.1
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• pp.74-80
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• 2002

A propulsion system apparatus for railroad vehicle is estimated it's performance because of safety and confidence. In general, flywheel type testing method is widely used in the equipment. However, mechanical inertia generated by the flywheel can not be varied (or controlled) and can not be represent actual running resistance. In this study, we have focused on the development of variable vehicle load generation. Therefore, we have proposed the method which uses variable vehicle load controlled by vector motor to get the characteristics of the real vehicle load and confirmed the results with those of computer simulations.

• Journal of the Korean Society for Railway
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• v.15 no.1
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• pp.9-16
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• 2012

The dynamic stability of railway vehicle has been one of the important issues in railway safety. The dynamic simulator has been used in the study about the dynamic stability of railway vehicle and wheel/rail interface optimization. Especially, a small scale simulator has been widely used in the fundamental study in the laboratory instead of full scale roller rig which is not cost effective and inconvenient to achieve diverse design parameters. But the technique for the design of the small scale simulator about the dynamic characteristics of the wheel-rail system and the bogie system has not been well developed in Korea. Therefore, the research using the small-scaled derailment simulator and the 1/5 scaled bogie has been conducted. In this paper, we did running stability test of 1/5 scaled bogie using small-scaled derailment simulator. Also, for the operation of the small scaled simulator, it is required to investigate the performance and characteristics of the simulator system. This could be achieved by a comparative study between an analysis and an experiment. This paper presented the analytical model which could be used for verifying the test results and understanding of the physical behavior of the dynamic system comprising the small- scaled derailment simulator and the 1/5 scaled bogie.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.166-172
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• 2016

This paper deals with the seismic qualification of the reflective metal insulation for thermal shielding that is installed on the outer surfaces of the main equipment of the primary coolant system of a nuclear power plant. A small-scale model of the reactor pressure vessel, which has equivalent dynamic characteristics, was designed to be tested in domestic seismic testing facilities in the future. In this study, seismic analysis of the small-scale model installed with metal insulation was performed using equivalent static analysis and response spectrum analysis. The required Response Spectrum for main equipment of the primary coolant system of APR-1400 plant were considered to establish the enveloping response spectrum, which was applied to the seismic analysis model. The results from two seismic analysis methods were compared to show the structural adequacy of the metal insulator design against a safe shutdown earthquake. This study will form the basis for the seismic testing to support the seismic qualification of the reflective metal insulator.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.12
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• pp.1195-1201
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• 2010

Performance tests of a supersonic exhaust diffuser were conducted by using a liquid rocket engine for simulating high-altitude environment. The experimental setup consisted of a combustion chamber, a vacuum chamber and a diffuser. The combustion tests for simulating high-altitude environment were carried out at three cases by chamber pressure variation(26, 29, 32barg). The test results showed that the diffuser was started at all case and vacuum chamber pressures were approximately 140torr. The starting pressure using combustion gas was similar with that of cold gas, but the vacuum chamber pressure was relatively high because of high temperature in the vacuum chamber. The results of this test can be used as an essential database for the design of real-scale high-altitude simulation test facility in the future.

• Smart Media Journal
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• v.12 no.5
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• pp.36-45
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• 2023

Recently, in digital agriculture, the types and utilization of greenhouses based on IoT are spreading, and greenhouses are being modernized, enlarged, and even factoryized using smart technology. However, a specific standardization plan has not been proposed according to the equipment for data collection in the smart greenhouse and the size or shape of the greenhouse. In other words, there is a lack of standard data for facility equipment, such as the type and number of sensors and equipment according to the size of the greenhouse, the type of greenhouse construction film and materials suitable for crops and carbon neutrality. Therefore, in this study, the suitability of the implementation, installation and quantity of IoT equipment for data collection was tested, and some standard technologies were presented through the implementation of data collection and communication methods. In addition, impact strength, tensile, tear, elongation, light transmittance, and lifespan issues for PE, PVC, and EVA, which account for about 90% of existing greenhouses, were presented, and the shape, size, and environmental problems of greenhouses made of films were presented. presented in the text. In this research paper, a standardized carbon-neutral modular smart greenhouse using nano-material film was implemented as a solution to environmental problems such as greenhouse size, farm crop type, greenhouse lifespan, and film, and its performance with existing greenhouses was analyzed and presented. Through this, we propose a modularized greenhouse that can be expanded or reduced freely without distinction in the size of the greenhouse or the shape of farmhouse crops, and the lifespan is extended and standardized. Finally, the average characteristics of greenhouses using existing PE, PVC, and EVA films and the characteristics of greenhouses using new carbon-neutral nanomaterials are compared and reviewed, and a plan to implement an expandable IoT greenhouse that supports carbon neutrality is proposed.