• International Journal of Aeronautical and Space Sciences
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• v.11 no.1
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• pp.26-30
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• 2010

The present paper studies the thermally-induced vibration phenomenon of the flexible space boom structure. In order to simulate the thermally-induced vibration phenomenon of the flexible thin boom structure of the spacecraft with the attached tip mass in space, the thermally-induced vibration including thermal flutter is experimentally investigated at various thermal environments using a heating lamp in vacuum chamber. In this experimental study, fluctuating characteristics, natural frequency and thermal strains of the thermally-induced vibration are parametrically investigated at various thermal environment conditions. Finally the thermally-induced vibration of the flexible boom structure of the orbiting earth satellite in solar radiation environment from the earth eclipse region including umbra and penumbra is simulated using the power control of the heating lamp in the vacuum chamber.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2002.11a
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• pp.130-136
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• 2002

Device makers want to make higher density chips as devices shrink, especially WSix poly stack down is one of the key issues. However, EPD (End Point Detection) time delay was happened in DPS+ poly chamber which is a barrier to achieve device shrink because EPD time delay killed test pattern and next generation device. To investigate the EPD time delay, a test was done with patterned wafers. This experimental was carried out combined with OES(Optical Emission Spectroscopy) and SEM (Scanning Electron Microscopy). OES was used to find corrected wavelength in WSix stack down gate etching. SEM was used to confirm WSix gate profile and gate oxide damage. Through the experiment, a new wavelength (252nm) line of plasma is selected for DPS+ chamber to call correct EPD in WSix stack down gate etching for current device and next generation device.

• Journal of Ocean Engineering and Technology
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• v.22 no.2
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• pp.1-6
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• 2008

Recently Oscillating Water Column (OWC) plants have been widely employed in wave energy conversion applications. It is necessary to investigate the chamber and optimize its shape parameters for maximizing air flow and energy conversion due to wave conditions. A 2D numerical wave tank based on a Fluent and VOF model is developed to generate the incident waves and is validated by theoretical solutions. The oscillating water column motion in the chamber predicted by the numerical method is compared with the available experimental data. Several geometric scales of the chamber are calculated to investigate the effect of the shape parameters on the oscillating water column motion and wave energy conversion.

• Journal of Ocean Engineering and Technology
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• v.26 no.3
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• pp.13-19
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• 2012

Recently, as the importance of the interior noise in a ship cabin has risen, ship builders have becomeconcerned about the use of noise reduction panels to reduce cabin noise. The results of previous researches have been based on analytical and experimental methods using simple sandwich panels. However, panel structures are becoming more complex to improve the transmission loss. Thus, researches that analyze the transmission loss of a panel are reaching the limit of study. This paper reports on research that was performed to determine the sound transmission characteristics of multi-complex panels applicable to high value-added vessels. It presents comparisons between analytical methods and experimental results by using a mini-reverberant chamber with components of sound attenuation panels, including the core and surface materials. The sound transmission loss of multi-complex panels are also analyzed in terms of the influences of the inside perforate plates and air gap thickness on the attenuation. Finally, the multi-complex panel with the highest noise attenuation is proposed based on the analysis results and experimental results in mini-reverberant chamber, which wereverified using a real-size reverberant chamber.

• Korean Journal of Environmental Agriculture
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• v.2 no.2
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• pp.103-107
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• 1983

The effect of photochemical oxidants on rice plants was measured by growing the rice plants Nihonbare in pot in charcoal-manganese oxide filtered atmosphere and non-filtered air. Visible injury on the leaf blades of rice plants were observed in plants grown under the unfiltered air chamber, but plants under filtered air chamber were free from any injury. Fresh weight of stem and root at maximum tillering stage in unfiltered chamber were 16.8 and 46.4% less than filtered air chamber, respectively. Grain yield in unfiltered air chamber was also reduced by 14.7% compared to that of filtered air chamber. And the reduced yield paralleled increase in concentration of oxidants in the atmosphere at the experimental site. ABA content in rice plants cultivated in unfiltered air chamber was higher than in filtered air chamber, but the root activity of rice plants in unfiltered air chamber was remarkably decreased.

• International Journal of Air-Conditioning and Refrigeration
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• v.16 no.3
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• pp.89-99
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• 2008

Indoor ozone has received attention because of its well-documented adverse effects on health. In addition to the inherently harmful effects of ozone, it can also initiate a series of reactions that generate potentially irritating oxidation products, including free radicals, aldehydes, organic acids and secondary organic aerosols (SOA). Especially, ozone reacts actively with terpene. The overarching goal of this work was to better understand ozone and terpene distributions within rooms. Towards this end, the paper has two parts. The first describes the development of a cylindrical test chamber that can be used to obtain the second order rate constant $(k_b)$ for the bi-molecular chemical reaction of ozone and terpene in the air phase. The second consists of model room experiments coupled with Computational Fluid Dynamics (CFD) analysis of the experimental scenarios to obtain ozone and terpene distributions in various turbulent flow fields. The results of CFD predictions were in reasonable agreement with the experimental measurements.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.138-144
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• 2004

Pneumatic damping through a orifice type duct for OWC type wave energy device is studied experimentally. Forced oscillation tests are made to measure chamber pressure and velocity of air flaw through orifice. Pneumatic damping coefficient are deducted from the experimental research, and discussion are made far the influence of frequency, heave amplitude, and orifice size. Finally two formula are proposed for the estimation of non-dimensional pneumatic damping coefficient by regression analysis. The proposed formula proves to be a reliable method far practical application.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.5
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• pp.640-647
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• 2002

An experimental investigation or the sonic and supersonic air ejector systems has beer conducted to develop design and prediction programs for practical ejector system. Five different primary nozzles have been employed to operate the ejector systems in the ranges of low and moderate operating pressure ratios. The ejector operating pressure ratio for the secondary chamber pressure to be minimized has a strong influence of the ejector throat ratio. The pressure inside the ejector diffuser is not dependent on the primary nozzle configurations employed but only a function of the ejector operating pressure ratio. Experimental results show that a supersonic ejector system is more desirable for obtaining high vacuum pressure of the secondary chamber than a sonic ejector system.

• Journal of Ocean Engineering and Technology
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• v.18 no.4 s.59
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• pp.8-14
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• 2004

Pneumatic damping through an orifice-type duct for an OWC-type wave energy device is studied experimentally. Forced oscillation tests are used to measure chamber pressure and velocity of air-flow through an orifice. Pneumatic damping coefficients are deducted from the experimental research, and the influence of frequency, heave amplitude, and orifice size are discussed. Finally, two formulas are proposed for the estimation of non-dimensional pneumatic damping coefficient by regression analysis. The proposed formula proves to be a reliable method for practical application.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.3
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• pp.250-257
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• 2004

Recently, the use of UVC lamps inside building air-conditioning system has been increasing in both medical and nonmedical buildings for the control of environmental microorganisms. In the present study, irradiance performance test of UVC lamp was carried out and surface sterilization effect of UV ray was investigated by using UV ray irradiation experimental chamber and pilot system. Experimental results show that the effective irradiance of UVC lamp is strongly dependent on air velocity and temperature with exception of relative huminity in air-conditioning system. An individual microbiological kill effectiveness experiment also shows that the fractional kill of two microbiological samples such as E. Coli and Legionella is roughly the same as the estimated fractional kill in the case of chamber test and pilot system test.