The relationship between tooth form and dietary preference is a crucial issue in vertebrate evolution. However, the mechanical properties of a tooth are influenced not only by its shape but also by its internal structure. Here, we use synchrotron transmission X-ray microscopy to examine the internal microstructures of multiple dinosaur teeth within a phylogenetic framework. We found that the internal microstructures of saurischian teeth are very different from advanced ornithischian teeth, reflecting differences in dental developmental strategies. The three-tissue composition (enamel–mantle dentin–bulk dentin) near the dentinoenamel junction (DEJ) in saurischian teeth represents the primitive condition of dinosaur teeth. Mantle dentin, greatly reduced or absent from DEJ in derived ornithischian teeth, is a key difference between Saurischia and Ornithischia. This may be related to the derived herbivorous feeding behavior of ornithischians, but interestingly, it is still retained in the herbivorous saurischian sauropods. The protective functions of mantle dentin with porous microstructures between enamel and bulk dentin inside typical saurischian teeth are also discussed using finite-element analysis method. Evolution of the dental modifications in ornithischian dinosaurs, with the absence of mantle dentin, may be related to changes in enamel characteristics with enamel spindles extending through the DEJ.

In this paper, we present an analysis of the performance of micronozzle/diffusers and we report on the fabrication and testing of a micronozzle/diffuser. We have found that the pressure loss coefficient for the nozzle/diffuser decreases with the Reynolds number. At a given Reynolds number, the pressure loss coefficient for the nozzle is higher than that of the diffuser due to a considerable difference in the momentum change. We find that the nozzle/diffuser length has little influence on the pressure loss coefficient. At a fixed volumetric flow rate, we encounter a ‘minimum’ phenomenon of the pressure loss coefficient versus nozzle/diffuser depth. This is related to the interactions of velocity change and friction factor. In this work, we find good agreement between the measured data and the predicted results, except for a diffuser having an opening angle of 20°. This is because of the presence of flow separation. The departure of this case from the prediction is due to the separation phenomenon in a diffuser with a larger angle.

The mechanism of enhancing the capacity of the LiFePO 4 cathodes in lithium ion batteries by the addition of a small amount of vanadium, which locate on the lithium site and induce lithium vacancies in the crystal structure, is reported in this article. As a result, the capacity increases from 138 mAh/g found for pristine LiFePO 4 to 155 mAh/g for the V-added compound, and the conductivity increases from 4.75 × 10 −4 S/cm for the LiFePO 4 without V addition to 1.9 × 10 −2 S/cm for the V-added compound. A possible model to facilitate the enhancement of conductivity and capacity is described with evidence supported by X-ray powder diffraction, X-ray absorption spectroscopy, and neutron powder diffraction data.

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