• Journal of KSNVE
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• v.7 no.6
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• pp.909-918
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• 1997

Combustion oriented noise is a part of engine noise, which is mainly determined by the in-cylinder pressure profile and the structure attenuation of an engine. A numerical model for predicting the in-cylinder pressure profile and the resultant combustion noise developed by the use of a commercial code. The model is experimentally validated and updated based on the performance as well as the noise by considering the fuel injection timing, the fuel injection rate, Cetane number, intake temperature, and compression ratio. For providing a design guide of a fuel injector for a low combustion noise engine model, the optimal parameters of injection pressure profile, injection rate profile, and injection timing are determined, which gives the 5 dBA noise reduction.

• Journal of the Korean Ceramic Society
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• v.40 no.12
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• pp.1202-1207
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• 2003

Using a recently developed Hybric Plasma-Particle Accelerating Impact Deposition (HP-PAID) process, synthesis of nanostructured silicon coatings has been investigated by injecting vapor-phase TEOS (tetraethosysilane, (C$_2$H$\_$5/O)$_4$Si) into an Ar hybrid plasma. The plasma jet with reactants was expanded through nozzle into a deposition chamber, with the pressure dropping from 700 to 10 torr. Ultrafine particles accelerated in the free jet downstream of the nozzle, deposited by an inertial impaction onto a temperature controlled substrate. By using this process, nanostructured amorphous silicon coatings with grain size smaller than 10 nm could be synthesized. These samples were annealed in an Ar and crystallized at 900$^{\circ}C$ for 30 min. TEM analysis showed that the annealed coatings were also composed of nanoparticles smaller than 10 nm, which showed a good consistency that the average grain size of 7 nm was also estimated from a peak shift of 2.39 cm$\^$-1/ and Full Width at Half Maximum (FWHM) 5.92 cm$\^$-1/ of Raman analysis. The noteworthy is that a strong PL peak at 398 nm was also obtained for this sample, which indicates that the deposited coatings also contained 3∼4 nm nanostructured grains.