Xinxin Chu

Preparation and thermal properties of epoxy composites filled with negative thermal expansion nanoparticles modified by a plasma treatment

Epoxy composites filled with negative thermal expansion nanoparticles, Mn3(Cu0.6Si 0.15Ge0.25)N, modified by a plasma treatment were prepared. Thermal expansion properties and thermal conductivities of the Mn3(Cu 0.6Si0.15Ge0.25)N/ epoxy composites were investigated within the temperature range of 77—300 K. Compared to neat epoxy resin, Mn3(Cu0.6Si0.15Ge0.25)N/epoxy composites show remarkably lower coefficient of thermal expansions (CTEs) and higher thermal conductivities. Especially for the composite with 32 vol.% of Mn3(Cu0.6Si0.15Ge0.25)N, the reduction of CTE value up to 42% in the temperature range of 77—195 K, and the thermal conductivities are 2.8 and 4 times as large as those of the neat epoxy resin at 298 and 77 K, respectively.Epoxy composites filled with negative thermal expansion nanoparticles, Mn3(Cu0.6Si 0.15Ge0.25)N, modified by a plasma treatment were prepared. Thermal expansion properties and thermal conductivities of the Mn3(Cu 0.6Si0.15Ge0.25)N/ epoxy composites were investigated within the temperature range of 77—300 K. Compared to neat epoxy resin, Mn3(Cu0.6Si0.15Ge0.25)N/epoxy composites show remarkably lower coefficient of thermal expansions (CTEs) and higher thermal conductivities. Especially for the composite with 32 vol.% of Mn3(Cu0.6Si0.15Ge0.25)N, the reduction of CTE value up to 42% in the temperature range of 77—195 K, and the thermal conductivities are 2.8 and 4 times as large as those of the neat epoxy resin at 298 and 77 K, respectively.

Cryogenic thermal expansion and electrical conductivities of Mn3CuN co-doped with Sb and Sn

A series of Sb and Sn co-doped anti-perovskite Mn3CuN materials were fabricated by mechanical ball milling followed by solid-state sintering. Their thermal expansion properties and electrical conductivities were investigated in the temperature range of 77-300 K. The results show that Mn3(CuxSb1-x)N (x=0.4, 0.5, 0.6, 0.7) exhibit negative thermal expansion (NTE) below 150 K, and the NTE temperature range shifts toward the lower temperature with the Sb increased. However, Sn doped in the Mn3(Cu0.5SbxSn1-x)N can lead the NTE behavior shifts to room temperature and the NTE operation-temperature window (ΔT) becomes broader. The electrical conductivities of Mn3(Cu0.5SbxSn1-x)N decrease with the temperature and Sb content increased.

A NEW CONFIGURATION OF MIXED STATE OBSERVED IN SUPERCONDUCTING SINGLE-CRYSTAL YBA2CU3O7-X

Abstract A kind of new cylindric configuration of mixed state was observed in YBa2Cu3O7−x single crystal superconductors at77K by Bitter decoration method.