Jianhua Liang

Effects of carbon nanotubes on the dehydrogenation behavior of magnesium hydride at relatively low temperatures

Dehydrogenation in MgH2 was found to lead to a transition from an incubation stage controlled by nucleation to an accelerated stage controlled by the movement of the interface. Addition of carbon nanotubes destabilized Mg–H bonding and reduced the energy barrier for nucleation, which is mainly related to the electron affinity of their curved surface.

First-Principles Study of the Structural Stability and Electronic and Elastic Properties of Helium in α-Zirconium

First-principles calculations within density functional theory have been performed to investigate the behaviors of helium in α-zirconium. The most favorable interstitial site for He in -Zr is not an ordinary tetrahedral or octahedral site, but a basal octahedral site with a formation energy as low as 2.40 eV. The formation energy reduces to 1.25 eV in the presence of preexisting vacancies. The analysis on the density of states and the charge density has been carried out. In addition, the influences of He and small He-V complexes on the elastic properties have been studied. The He-V complexes have been found to greatly affect the elastic properties compared with He alone.

Hydrogen Isotope Effects of Ti, Zr Metals

Abstract The p-c-T curves of D2 and T2 absorption by Ti and Zr were measured. there are one plateau at temperature below 300 °C and two plateaus at temperature range of 500∼600 °C for Ti but one plateau below 525°C and two plateaus above 525°C for Zr. The thermodynamic parameters on different phases were determined and there are obvious thermodynamic isotope effects. The lag effect was not observed for Ti but its existent for Zr. The kinetic p-t curves of absorption were investigated at different temperature ranges and then the rate constants are calculated. The results show that the rate constants increase with raising temperature for Ti but decrease for Zr. The activation energy values are (110.2±3.0), (155.7±3.2) kJ.mol-1 respectively for Ti and (-25.9±0.7), (-6.8±0.8) kJ.mol-1 for Zr. The kinetic p-t curves of desorption were investigated too and the activation energy of desorption are (42.3±1.9), (62.1±1.6) kJ.mol-1 respectively for Ti and (40.1±0.8), (57.7±1.6) kJ.mol-1 for Zr. So there are remarkable kinetic isotope effects for Ti, Zr.