Development of ultra micro-displacement using micro-coiled carbon fiber

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In the tensile sxperiments using an optical microscope, load was applied by a weight, which was a piece of cover glass in our experiments. The weight was connected to one end of a coiled carbon, of which the other end was fixed. BY inclining the optical microscope gradually together with the microscope stage, we observed that the weight slid on the specimen. We took accurate measurements of the coiled carbon elongations from optical micrographs at inclination angles of 40ﾟ and 50ﾟ.The shear modulus G of the material is given by 64nr^4w/d^4delta where, d is the fiber diameter, r the coil radius, delta the amount of elongation and n the number of turns. The calculated shear modulus of the coiled carbon fiber is G=85 GPa.The bulk electrical resistivity of the carbon coils was 1.0-0.2OMEGAcm depending on the bulk density. On the oter hand, the electrical resistivity on one carbon coil which is about 1mm in length, 8mum in coil diameter and 2mum in fiber diameter. The calculated electrical resistivity of the fiber was 1.09*10^<-2>OMEGAcm.