• Journal of KSNVE
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• v.9 no.3
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• pp.493-501
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• 1999

The vibration modes of resilient mounting system and foundation structure which support diesel engine/generator set and acoustic enclosure walls play an important role in the vibration transmission process. So, it is necessary to perform vibration mode analysis of resilient mounting system and foundation structure. For some reasons, if the vibration modal analysis of resilient mounting system and foundation structure of acoustic enclosure could be simultaneously done by finite element method, it would be very efficient approach. In this paper, vibration modal analysis method using finite element method for multi stage mounting system having n d.o.f model was proposed. Vibration analysis of single and double stage resilient mounting system was performed to verify the validity of the proposed method. Also frequency response results were compared in case of rigid foundation model and finite element foundation model which was compared with experimental modal analysis results.

• Journal of computational fluids engineering
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• v.14 no.2
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• pp.39-45
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• 2009

In engine room, proper enclosure system is preferable for reducing noise level but the enclosure system in the engine room causes bad influence on cooling performance due to poor ventilation. Cooling efficiency of the enclosure system can be improved by varying fan speed and proper flow path for ventilation. In this study, numerical analysis is performed to assess cooling effect of the enclosure system using finite volume method. The RNG k-$\varepsilon$ model is adopted for turbulence model along with heat exchanger model and porous media model for heat exchanger analysis, and moving reference frame model for rotational fan. Verification result shows reasonable agreement with experimental data. Analysis results show direct effect of velocity and temperature distribution on cooling ability in the enclosure system. Enclosure system of case B shows high heat transfer coefficient and has the smallest area ratio of opened flow passages which is good for noise level reduction.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.170-176
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• 2008

The concept design of Flexible Seal for thrust vector control of solid motor was performed. Through the concept design, the optimum pivot point of flexible seal, cross-section configuration of flexible seal and thermal protection system from combustion gas was decided. The pivot point of flexible seal has aft pivot type and cross-section view is conical type. For satisfying a spring torque rate, the shear modulus of rubber has the value of under about 0.6MPa and failure shear stress has over about 2.5MPa.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.3
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• pp.36-42
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• 2017

• Proceedings of the Korean Nuclear Society Conference
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• 1998.10a
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• pp.318-318
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• 1998

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.350-351
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• 2005

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2010.10a
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• pp.295-296
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• 2010

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2011.10a
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• pp.501-502
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• 2011

• Journal of the Korean Society of Radiology
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• v.7 no.2
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• pp.113-120
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• 2013

Nowadays, the medical system towards patients changes into the medical services. As the human rights are improved and the capitalism is enlarged, the rights and needs of patients are gradually increasing. Also, based on this change, several systems in hospitals are revised according to the convenience and needs of patients. Thus, the cases of mobile portable among examinations are getting augmented. Because the number of mobile portable examinations in patient's room, intensive care unit, operating room and recovery room increases, neighboring patients are unnecessarily exposed to radiation so that the examination is legally regulated. Hospitals have to specify that "In case that the examination is taken out of the operating room, emergency room or intensive care units, the portable medical X-ray protective blocks should be set" in accordance with the standards of radiation protective facility in diagnostic radiological system. Some keep this regulation well, but mostly they do not keep. In this study, we shielded around the Collimator where the radiation is detected and then checked the change of dose regarding that of angles in portable tube and collimator before and after shielding. Moreover, we tried to figure out the effects of shielding on dose according to the distance change between patients' beds. As a result, the neighboring areas around the collimator are affected by the shielding. After shielding, the radiation is blocked 20% more than doing nothing. When doing the portable examination, the exposure doses are increased $0^{\circ}C$, $90^{\circ}C$ and $45^{\circ}C$ in order. At the time when the angle is set, the change of doses around the collimator decline after shielding. In addition, the exposure doses related to the distance of beds are less at 1m than 0.5m. In consideration of the shielding effects, putting the beds as far as possible is the best way to block the radiation, which is close to 100%. Next thing is shielding the collimator and its effect is about 20%, and it is more or less 10% by controlling the angles. When taking the portable examination, it is better to keep the patients and guardians far enough away to reduce the exposure doses. However, in case that the bed is fixed and the patient cannot move, it is suggested to shield around the collimator. Furthermore, $90^{\circ}C$ of collimator and tube is recommended. If it is not possible, the examination should be taken at $0^{\circ}C$ and $45^{\circ}C$ is better to be disallowed. The radiation-related workers should be aware of above results, and apply them to themselves in practice. Also, it is recommended to carry out researches and try hard to figure out the ways of reducing the exposure doses and shielding the radiation effectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5140-5147
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• 2012

It is difficult for systematic and flexible control reflecting regional characteristics with only public policies that control the landscape. Also, in the event that there is no preceding quantitative index calculation, it is impossible for the public society to come to an agreement. Therefore, the development of a shielding analysis simulation methodology that makes data processing modeling that can be interlinked with the urban information system is a very meaningful study. Thus, this study presents urban space shielding simulation technologies and quantitative analysis methodologies using 3D graphic engines and deduces the optimal design by integrating the data of the geographic information system (GIS) in order to suggest the potential as an analysis model that can be used in future urban information systems.