• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.9
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• pp.834-840
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• 2010

The Sound reduction indices(SRIs) of interior door with 13 different size apertures are measured in acoustic chamber. Also, as a theoretical approach, the SRIs are estimated using Gomperts' theory. In this study, the aperture of interior door is focused on the lower part of door leaf which is well known as a main cause to deteriorate the sound insulation performance of door. The results show that the SRI of door strongly depends on the aperture width and the dip in the measured sound reduction index curve by the resonance effect within aperture is observed at high-frequency. On the whole, the values calculated by theory are in good agreement with the measured values including the position of resonance dip. The average difference between the measured and the calculated values is 0.9 dB for 13 doors with different size aperture in terms of the weighted SRI.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.2
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• pp.17-23
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• 2004

The effects of refining consistency and plate gap on the specific energy consumption and physical properties of liner were investigated. Higher refining consistency and narrower plate gap brought about the reduction of specific energy consumption to decrease the freeness. Refining consistency and plate gap did not affect the bulk, Taber stiffness and compression index. The reduction of freeness and/or the increase of specific energy consumption caused the decrease of bulk and Taber stiffness, but increased the compression index. The effect of grammage on bulk was not observed, but Taber stiffness and compression index were increased with grammage. The bulk was decreased with the reduction of freeness rapidly at the above 400 mL CSF, and then levelled off. It is expected that the reduction of energy consumption could be obtained from the application of higher refining consistency and narrower plate gap during refining.

• Journal of the Korean institute of surface engineering
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• v.51 no.3
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• pp.179-184
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• 2018

In this study, Ni and tungsten carbide (WC) nanoparticles are simultaneously synthesized with the mesoporous carbon nanoparticles (CNP) using a solution plasma processing (SPP) in the benzene. The Ni and WC nanoparticles were formed through the sputtering effect of electrodes during discharge, and mean time CNP were formed through reduction reaction. TEM observation showed that loaded Ni and WC nanoparticles were evenly dispersed on the CNP. The results of electrochemical analysis demonstrated that an introduction of Ni nanoparticles promoted to improve catalytic activity for oxygen reduction reaction (ORR). Moreover, Ni-WC/CNP lead to fast electron transfer process compared to that of WC/CNP. Therefore, the inexpensive Ni-WC/CNP might be a promising as catalytic material for cathodes in fuel cell applications.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.12
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• pp.940-949
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• 2013

In this paper, wrinkle reduction design was studied for triangular sail. Wrinkles in the solar sail membrane can change the load path and surface topology which may have an adverse effect on propulsion performance and controllability. In this study, wrinkle reduction strategies of adjusting cable angle, catenary and catenary-wire schemes were considered and the design parameters for wrinkle reduction were systematically investigated.

• The Korean Journal of Ceramics
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• v.4 no.4
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• pp.387-393
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• 1998

The formation of titanium diboride ($TiB_2$ ) via the reduction of $TiO_2$ with boric oxide and carbon was studied in a partially reducing atmosphere of argon mixed with 4 vol.%H2. The effect of reaction time, temperature, partial pressure of nitrogen and $TiO_2/B_2_O3$ stoichiometric ratio on the reducibility of oxides has been studied. The phases formed were analysed by using X-ray rowder diffraction and scanning sosctron microscopic techniques. In this paper, we also investigated the presence of $CaC_2$ as a reducing agent on the reducibility of oxide mixtures and on the Ti-B-C-Ca-O phase equilibria. The morphology of $TiB_2$ formed in the presence of $CaC_2$ is compared with the microstructure of $TiB_2$ formed as a consequence of carbothermic reduction. The observed variation in $TiB_2$ crystals formed is also explained.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1484-1488
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• 2009

This paper analyzes the noise reduction of traction motor for rolling stock. Nowadays, rolling stock becomes a attractive transportation as a friendly environment transportation. And this paper showed that vibration noise of motor coil by inverter switching frequency. That noise has influence on passenger. It is important that noise reduction for passenger in the rolling stock. In this paper, it shows that effect of variable switching frequency of propulsion inverter for noise reduction.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.5
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• pp.679-686
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• 1999

This study is to investigate the effect of a substantial drag reduction caused by the polymer(A611P) when the working fluids flow to the vertical direction in the vertical cylindrical equipment of closed flow system. The drag reduction is associated with the mechanical degrada-tion thermal degradation and heat transfer. By ignore the heat fluxs within the closed system the pressure drop due to the polymer concentration the flow velocity and flow time have been mea-sured. By taking into account the mechanical and thermal degradation in the closed system an experiment has been focused on the determination of the condition which could improve the pump capacity in the heat union electric power plant. Under the condition of non-boiling it has been found out that the change of heat flux has little influence on the drag reduction.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.10 no.1
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• pp.7-11
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• 2010

In this paper, we propose an improved speech/music discrimination method based on a feature combination and dimensionality reduction approach. To improve discrimination ability, we use a feature based on spectral duration analysis and employ the hierarchical dimensionality reduction (HDR) method to reduce the effect of correlated features. Through various kinds of experiments on speech and music, it is shown that the proposed method showed high discrimination results when compared with conventional methods.

• Journal of the Korean Society for Railway
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• v.4 no.1
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• pp.31-37
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• 2001

There are three examples of noise reduction test by joint improvement. One of them is tested for electric car at joint rail and another is tested at expansion joint and long welded rail and the third is tested at open deck bridge. We can know from the result that the noise reduction effect of rail welding is very different to the type of track and the car. The condition of the test has some differences, but it may be useful reference of noise reduction

• Journal of Oral Medicine and Pain
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• v.23 no.3
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• pp.277-280
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• 1998

The treatment of anterior disc displacement without reduction patients needs speicific treatment methods different from other Craniomandibular Disorders. Those are manual manipulation, anterior repositioning splint; ARS and step-back. It is well known that the use of Anterior Repositioning Splint is effective on relief of TMJ symptom. But the side effect of long- term ARS wearing, which is irreversible posterior open bite induction, has made many clinicians avoid ARS treatment. This report introduces a clinical case recently proven part- time wearing ARS method for treatment of Disc Displacement without reduction patient' that can reduce side effects with good efficacy. But now clinical statistical studies and basical histophysiological studies are more needed.