We report a general approach to fabricate elastomeric composites possessing high electrical conductivity for applications ranging from wireless charging interfaces to stretchable electronics. By using arbitrary nine kinds of rubbers as matrices, we experimentally demonstrate that the matching the solubility parameter of CNTs and the rubber matrix is important to achieve higher electrical conductivity in CNT/rubber composite, resulting in continuous conductive pathways leading to electrical conductivities as high as 15 S/cm with 10 vol% CNT in fluorinated rubber. Further, using thermodynamic considerations, we demonstrate an approach to mix CNTs to arbitrary rubber matrices regardless of solubility parameter of matrices by adding small amounts of fluorinated rubber as a polymeric-compatibilizer of CNTs. We thereby achieved electrical conductivities ranging from 1.2 to 13.8 S/cm (10 vol% CNTs) using nine varieties of rubber matrices differing in chemical structures and physical properties. Finally, we investigated the components of solubility parameter of CNT by using Hansen solubility parameters, these findings may useful for controlling solubility parameter of CNTs.

Wurtzite gallium nitride (GaN) has a polarity along the c-axis and piezoelectric properties the same as aluminum nitride. Since it has a high mechanical quality factor and high output sensitivity, it is expected to perform well in piezo micro-electro-mechanical system devices. This paper demonstrates that Hf and Mo interlayers enable the preparation of highly (001)-oriented GaN films via conventional sputtering at a low temperature (400 °C). The piezoelectric coefficient d33 of the prepared undoped GaN films is equivalent to that of a single-crystal GaN. Furthermore, the results demonstrate that the piezoelectric response of GaN films increases significantly when they are doped with scandium (Sc). Although this enhancement was predicted theoretically, the piezoelectric response of Sc-doped GaN films prepared on Hf and Mo interlayers has shown great improvement. Moreover, bulk acoustic wave resonators constructed using Sc-doped GaN films show a piezoelectric coupling factor that is three times larger than that of a single-crystal GaN.

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Recently, high strength artificial lightweight aggregates are being used for lightweight concrete as structural material in this country.Lightweight concrete seems to have different property from that of normal concrete, and requires specific treatment in the design and execution of structures.In order to study the fundamental properties of the lightweight concrete with artificial lightweight aggregates, measurement and observation were made of the consistency of fresh lightweight concrete and of the compressive strength and static modulus of elasticity of hardened lightweight concrete. The results obtained from these experiments were discussed in comparison with those of normal concrete.The diagonal tension test and the fatigue test were conducted on the beams of lightweight concrete and those of normal concrete.The investigation was made of their properties of the diagonal tensile strength, the fatigue properties, the behavior of the bond stress distribution, the behavior of the crack, and so on.