Abstract: A double-layer rack includes a PCIe card frame, a network card frame, a PCIe riser card and a network card connector assembly. The PCIe card frame is stacked on the network card frame. The network card frame has a network card accommodation space for selectively receiving one OCP network card, two OCP network cards or one data processing unit. The PCIe riser card is disposed in the PCIe accommodation space. The network card connector assembly is disposed in the network card accommodation space. The double-layer rack further includes a blocker component and a divider plate selectively and removably disposed on the network card frame, so that the network card accommodation space forms various accommodation space configurations for selectively receiving the one OCP network card, the two OCP network cards or the one data processing unit.

Abstract: A shape-memory polymer foam is disclosed, which is formed by kneading a shape-memory copolyester with a polymeric material having a relatively lower crystallinity in a weight ratio of 15:85 to 85:15 and then conducting a foaming process. The shape-memory copolyester is a random copolymer formed from a dicarboxylic acid mixture and a diol in excess through esterfication and polycondensation. The dicarboxylic acid mixture includes 30-99 mol % of an aromatic dicarboxylic acid and 70-1 mol % of a straight aliphatic dicarboxylic acid of C4-C10. The diol includes a straight aliphatic diol of C2-C10.