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강신민,김석룡 慶尙大學校 1990 論文集 Vol.29 No.1
In classical constuctions the exercise uses a straight edge and a pair of compasses. As in Paper-foldings are not used them, it is impossible to describe a circle or other curves. However, we can receive easily several important geometic processes, to divide straight lines and angles into two or more equal parts to draw perpendiculars and parallels to straight lines. In this paper, I'll make again how to make regular polygons(regular 3-gon, 4-gon, 5-gon, 6-gon, 8-gon, 10-gon, 12-gon) while are confined in some degree by Paper-foldings and make regular 8-gon, 12-gon among them with other method. Finally, I will put the point in making a regular 9-gon which is impossible with a straight edge and a pair of compasses by using any angle into three sections in Paper-foldings and I will explain the course that Paper-foldings maks any angle into three sections which is impossible with only a straight edge and a pair of compasses possible.
PZT 파우더 첨가에 따른 티타늄 파우더/폴리머 콘크리트 복합재료의 진동 특성 및 압축 물성 분석
박재현,김석룡,김경수,김건,김석호,이범주,정안목,안종욱,김선주,이시맥,유형민,Park, Jaehyun,Kim, Seok-Ryong,Kim, Kyoung-Soo,Kim, Geon,Kim, Seok-Ho,Lee, Beom-Joo,Jeong, Anmok,An, Jonguk,Kim, Seon Ju,Lee, Si-Maek,Yoo, Hyeong-Min 한국복합재료학회 2022 Composites research Vol.35 No.3
In this study, Ti powder/Polymer concrete composites were processed by adding the PZT powder, one of the piezoelectric materials, to improve the vibration damping effect of Polymer concrete. Ti powder was added at a constant ratio in order to maximize the vibration damping effect using the piezoelectric effect. Three types of composite material specimens were prepared: a specimen without PZT powder, specimens with 2.5 wt% and 5 wt% of PZT powder. The vibration characteristics and compression properties were analyzed for all specimens. As a result, it was confirmed that as the addition ratio of PZT powder increased, the Inertance value at the resonant frequency decreased due to the piezoelectric effect when the vibration generated from Ti powder/polymer concrete was transmitted. Especially, the Inertance value was decreased by about 19.3% compared to the specimen without PZT at the resonant frequency. The change in acceleration with time also significantly decreased as PZT powder was added, confirming the effect of PZT addition. In addition, through the compression strength test, it was found that the degree of deterioration in compression properties due to the addition of PZT up to 5 wt% was insignificant, and it was confirmed that the powder was evenly dispersed in the composites through the cross-sectional analysis of the specimen.