• Journal of the Korean Ceramic Society
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• v.35 no.12
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• pp.1316-1322
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• 1998

The amount of VC and C/N ratio in Ti(CN) was varied to investigate the effect of VC addition on the mi-crostructural change in Ti(CN)-Ni system. As the amount of VC addition increases in Ti(C0.7N0.3)-20Ni sys-tem a complete solid solution was observed in Ti(C0.7N0.3)-20Ni-25VC system. It implies that the ratio of the dissolution rates of Ti(C0.7N0.3)to that of VC is nearly 2:1 at the sintering conditions used in this study. It was found from the experiments that the system composed of the Ti(C0.7N0.3) phase exhibits a rimless structure and relatively small amount of solid solution. That is among Ti(C0.7N0.3) phase exhibits a rimless structure and relatively small amount of solid solution. This is among Ti(C1-xNx) phases the dissolution rate of Ti(C0.3N0.7) is the lowest. Also fracture toughness(KIC) of the cermet was measured by indentation method. Attentions were paid to crack propagation path to look for a dominant fracture mode and to cor-relate it with fracture toughness values. The fracture toughness was relatively high with the addition of VC content. But the addition of a large VC content reduced the overall toughness of the cermet. This result is explained with the difference in fracture mode.

• Journal of Broadcast Engineering
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• v.9 no.4 s.25
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• pp.424-433
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• 2004

Jing(gong) is one of the most well known Korean traditional Samulnori instruments to the general public. Samulnori is consisted of four instruments, them being : the jingo the janggu (hour-glass drum). the kkwaenggwari, and the buk(drum). Of the four instruments, the jing with its deep, and yet soft and beautiful long lingering sound embraces the sounds of the other three. The jing is a brassware instrument, a compound of $70{\%}\;copper\;and\;22{\%}\;tin.$\;A high quality brassware is used when the jing is made. The jing is shaped with a 39-40cm circular plate and a rim that gives 7.0-7.5cm of depth to the instrument. Even with its most simple structure, when the circular plate is hit during performance, the rim which supports the circular plate gives resonance to the sound making low-frequency sounds. Therefore the range of the representative frequency of the full rim jing is between $118.4{\~}366.0[Hz],$\;the lingering sound lasts for more than 20 seconds afterwards. When the jing with half of its rim cut off is hit the basic frequency is $139.9{\~}387.5[Hz].$\;And the sound lasted for ten more seconds. The jing of its rimless frequencies are distributed between $990.5{\~}1,372[Hz].$\;And the lingering sound lasts for 5seconds afterwards. Therefore, different thickness and depth of the rim may give new resonance frequencies and alter the longing time of the sound. This thesis paper will try to reveal the relationship between the thickness or depth of the rim (which holds the bending circular plate) and the frequency or the lasting time of the sound.