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PTFE/copper composites were prepared by compression molding at room temperature and subsequent heat treatment in the atmosphere. Transfer films were prepared on a GCr15 disc using different loads, speeds and morphologies of the counterface. The tribological behavior, thickness and morphology of these transfer films were studied. A scanning electron microscope, a laser microscopic 3D and profile measurement apparatus and an energy-dispersive X-ray spectrometer were used for analysis of the morphology, thickness and elemental content of the transfer film, respectively. The results showed that sliding speed, contact pressure and morphology of the counterface have significant effects on the thickness and tribological behavior of the transfer film. Low speed, light load and isotropic surface morphology are highly conducive to the formation of a transfer film with excellent tribological properties.

Ornithopods were the most important group of Cretaceous ornithischians and achieved high levels of abundance and taxonomic diversity. An understanding of the phylogeny, early evolution and diagnosis of the clade is hampered by a shortage of detailed anatomical descriptions of basal taxa. One of the most important basal ornithopod taxa discovered in recent years is Changchunsaurus parvus, from the Quantou Formation (‘middle’ Cretaceous) of Jilin Province, China, represented by excellent cranial and postcranial material. Here, we present the first description of the postcranial anatomy of the holotype specimen of Changchunsaurus and provide comparisons to other basal cerapodans and basal ornithopods. A phylogenetic analysis finds relationships amongst basal ornithopods to be extremely poorly resolved, but supports a sister-group relationship between Changchunsaurus and Jeholosaurus shangyuanensis from the Yixian Formation (late Barremian–early Aptian) of Liaoning Province, China. Numerous characters distinguish the two taxa, supporting their generic distinction. The proposed sister-group relationship suggests that an endemic clade of small-bodied bipedal ornithopods existed in north-east China during the Early to ‘middle’ Cretaceous.

The Quantou Formation of Jilin Province, People's Republic of China, has recently yielded an important new fauna of ‘middle’ Cretaceous vertebrates. This fauna includes the small-bodied cerapodan ornithischian dinosaur Changchunsaurus parvus, represented by excellent cranial and postcranial material. When initially described, Changchunsaurus was hypothesed to represent one of the most basal known ornithopods; however, similarities to ceratopsians were also noted, suggesting that Changchunsaurus may be crucial to elucidating the interrelationships of basal cerapodans, one of most problematic areas of ornithischian phylogeny. Here we present a detailed description of the craniodental anatomy of Changchunsaurus, rediagnose the taxon based upon three autapomorphies, and provide comparisons to other basal cerapodans, as a foundation for future studies of basal cerapodan relationships. Changchunsaurus shows strong similarities to the Chinese Early Cretaceous cerapodan Jeholosaurus, and it is likely tha...