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High electrical and thermal conductivity are beneficial to the shape recovery performance of electroactive shape memory polymer composites. In this work, the chopped carbon fiber (CCF) was processed into silver plated chopped carbon fiber (Ag/CCF), and the Ag/CCF was filled into hydrogenated bisphenol A epoxy (H-EP) resin to fabricate the electro-induced shape memory polymer composites. The Ag/CCF/H-EP composites show good electrical and thermal conductivity compared to the CCF/H-EP composites. When the content of Ag/CCF reaches 1.8 wt%, the e Ag/CCF/H-EP composites reach the threshold of thermal conductivity, electrical conductivity and percolation. The thermal conductivity of H-EP composite with 5.4 wt% Ag/CCF is 2.33 W/(m•K), which is 2.6 times and 12 times of that of CCF/H-EP composite and H-EP matrix, respectively. When the content of Ag/CCF reaches 7.2 wt%, the volume resistivity of Ag/CCF/H-EP composites decrease from 1.69 × 10 16 •to 9.51 × 10 3 cm, and surface resistivity from 6.91 × 10 15 to 6.19 × 10 2 , respectively. And the Ag/CCF/H-EP composites show good mechanical properties and dynamic thermomechanical properties. When the content of Ag/CCF is more than 1.8 wt%, the Ag/CCF/H-EP composites exhibit excellent electroactive shape memory performance, and the shape recovery rate of the composites is more than 92%.

Mud cooling is a key technology in gas hydrate drilling operation. GHMCS (Gas Hydrate Mud Cooling System) proposed in this paper is a set of special equipment used to cool mud. The working principle, design calculations, and basic composition of the system are introduced in this paper. Laboratory experiments were carried out on the system to test its mud cooling effects. Field experiments were also carried out on the system in three gas hydrate drilling wells located in the Muli basin of Qinghai province, China. The experiments proved that the system not only achieved the goal of the design completely, but also met the mud temperature requirement of gas hydrate drilling.

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