Self-irradiation effects in plutonium/IV/ hydroxo phenyl acetate Pu/OH/3/C6H5CH2COO/ and plutonium/IV/ hydroxo α-naphthyl acetate Pu/OH/3/C10H7CH2COO/: EPR investigations

Self-irradiation effects due to -radiation in plutonium/IV/ hydroxo phenyl acetate, Pu/OH/₃/C₆H₅CH₂COO/ and hydroxo -naphthyl acetate, Pu/OH/₃/C₁₀H₇CH₂COO/ have been studied by EPR technique. OH and C₆H₅CH₂COO^. species are identified in the phenyl acetate while the C₁₀H₇CH₂COO^. species is detected in -naphthyl acetate. The values of the efficiency parameter, , determined for OH, C₆H₅CH₂COO^. and C₁₀H₇CH₂COO^. species are 0.8, 1.31 and 2.18, respectively. The results are interpreted on the basis of the thermal spikes associated with the alpha particle interaction with the lattice.     

Role of hydrogen in catalytic dehydrogenation: Film diffusion controlled deactivation

The function of hydrogen used as carrier gas in catalytic dehydrogenation is to increase the selectivity and stability of catalysts. It slows down catalyst deactivation by either inhibiting deposition of potential coke precursors or facilitating their desorption by rehydrogenation. This function, in gas-solid catalytic dehydrogenation appears to be interphase mass transfer controlled by increased hydrogen linear flow velocities decreasing the extent of deactivation. Besides, deactivation appears to progress through two regimes, an initial short term followed by a long term deactivation.     

STUDIES OF PHOSPHAZENES. PART VI.1 THE PREPARATION OF THE ISOMERIC TETRACHLOROBIS-ISOPROPYLAMINOCYCLOTRIPHOSPHAZATRIENES

Abstract

The three isomers of N₃P₃Cl₄(NHPr¹)₂ have been prepared and separated by gas-liquid chromatography. Their structures have been assigned on the basis of ¹H and ³¹P nmr data.     

Phase transitions in the SrHfO3 perovskite measured with 111In/111Cd PAC

The temperature dependence of the hyperfine parameters in SrHfO₃ powder samples has been investigated by means of Perturbed Angular Correlation spectroscopy using implanted ¹¹¹In probes. Three quadrupole interactions have been established, with the largest fraction showing a pronounced dynamic interaction. We assign this fraction to ¹¹¹In / ¹¹¹Cd probe atoms on substitutional Hf sites. The temperature dependence of the dynamic interaction has been associated to the Pnma↔Imma phase transition at ∼700 K. We discuss the results in relation to those obtained for ¹⁸¹Hf / ¹¹¹Ta-probes in AHfO₃ (A=Ba, Sr, Ca) and for ¹¹¹In / ¹¹¹Cd-probes in PbZrO₃ and BaTiO₃. This revised version was published online in August 2006 with corrections to the Cover Date.