With first-principles virtual-crystal approximation calculations, we systematically investigate the geometric and elec- tronic structures as well as the phase transition of lead zirconate titanate （PbZr 1-xTixO3 or PZT） as a function of Ti content for the whole range of 0 〈 XTi 〈 1. It can be found that, with the increase of the Ti content, the PbZr1-xTixO3 solid solutions undergo a rhombohedral-to-tetragonal phase transition, which is consistent with the experimental results. In addition, we also show the evolution in geometric and electronic structures of rhombohedral and tetragonal PbZr1-xTixO3 with the increasing content of Ti.
Carbon nitride （CN,） and diamond-like carbon （DLC） coatings were prepared by dc magnetron sputtering at room temperature. Different partial pressures of N2 were used to synthesize CNx to evaluate the relationship between the atomic percentage of ni- trogen and hemocompatibility. Auger electron spectroscopy and atomic force microscopy indicated atomic percentages of N of 0.12 and 0.22 and that the CNx coatings were smooth. An in vitro study of the hemocompatibility of the coatings revealed that both CNx coatings had better anticoagulant properties and lower platelet adhesion than DLC. Compared with CN0.1〉 the CN0.22 coating showed longer dynamic clotting time （about 42 min）, static clotting time （23.6 min） and recalcification time （45.6 s）, as well as lower platelet adhesion （102 cells μm-2）, aggregation, and activation. The presence of nitrogen in the CNx coatings in- duced their enhanced hemocompatibility compared with DLC.
