Qing-Qing Ni

DISTRIBUTION OF TRABECULAE AND ELYTRAL SURFACE STRUCTURES OF THE HORNED BEETLE, ALLOMYRINA DICHOTOMA (LINNÉ) (COLEOPTERA: SCARABAEIDAE)

Abstract To clarify the dynamic construction of Allomyrina dichotoma (Linné) elytra, the distribution of trabeculae and surface structures has been investigated using scanning electron microscopy and transmitted light. There are solid trabeculae in the elytron and under penetrating light these can be seen as black dots. It is clear that trabeculae arrangement is almost entirely irregular throughout the elytron, except for some approximately straight alignment near some trachea. This irregular arrangement is different from the longitudinal rows of striations that are well known in other species, and there are no hollowed striae (punctures) on the elytral surface of A. dichotoma. Throughout the internal architecture of the elytron, there are mesh‐like (honeycomb) structures. Each honeycomb usually has 1–2 trabeculae mainly distributed at the corners of the honeycomb. The number of trabeculae present on each honeycomb is dependent on the size of the honeycomb.

FINE STRUCTURE OF TRABECULA IN THE ELYTRA OF ALLOMYRINA DICHOTOMA (LINNE) AND PROSOPOCOILUS INCLINATUS (MOTSCHULSKY) (COLEOPTERA: SCARABAEEDAE)

Abstract To obtain new ideas on optimal composite material structure, the fine structures of the trabeculae of the elytra of Allomyrina dichotoma (Iinné) and Prosopocoilus inclinatus (Motschulsky) were investigated using scanning electron microscope. The shape and size of trabeculae, which form the internal bridges between the upper and lower surfaces of the elytra, depend on the species of beetles. Complex surface structures (stripes or bandings) were found in those of A. dichotoma, but less in P. inclinatus. The trabeculae consisted of three parts: the surface part, the cylindrical layer and the central part. The surface and the central part were mainly protein substances which could be dissolved by KOH. The cylindrical layer had many chitin fibers with different orientation, and they were embedded in a protein matrix, and were connected to endocuticle chitin fibers on the upper and lower parts of the lamination.

Interfacial Behavior of Fiber/Matrix Based on of Middle Layer of Organic-Inorganic Nano Hybrid

It was expected that the performance of a polymer based composite and its interfacial behavior of fiber/matrix could be improved by using organic substance and/or organic-inorganic hybrid. In this paper, the new approach of using organic-inorganic nano-hybrid as a middle layer to improve the interfacial performance of composites was proposed. Several typical reinforcements such as continuous glass fiber, chopped strand glass fiber and glass fabric were treated by epoxy/silica nano-hybrid and a middle layer between reinforcement of glass fibers and the matrix of epoxy resin was introduced. The composites with this nano-hybrid middle layer for reinforcements were fabricated. Then the interfacial behavior with and/or without the hybrid middle layer was investigated and compared by the fragmentation test with simultaneous AE measurements, peeling tests and SEM observation. It was found that the interfacial behavior between glass fiber and epoxy resin could be improved greatly by introducing the middle layer of epoxy/silica nano-hybrid. It was confident that the concept of using organic-inorganic hybrid as a middle layer between reinforcements and matrix would be one of effective approaches for improvement of the interfacial behavior in composites.