Showing papers by "University of Mons published in 1980"
TL;DR: In this article, solid state reactions between ZrO2· SiO2 and αAl2O3 in mixed powders were studied by quantitative X-ray diffraction, density measurements and qualitative EDAX.
Abstract: Solid state reactions between ZrO2· SiO2 and αAl2O3 in mixed powders were studied by quantitative X-ray diffraction, density measurements and qualitative EDAX. Data were obtained at temperatures ranging from 1400 to 1600° C for 5 h; the initial molar ratios of the reactants (Al2O3/ZrO2 · SiO2) varying from 0 to 5. The results indicate that: (1) ZrO2· SiO2 and αAl2O3 react and form ZrO2, crystalline 3Al2O3 · 2SiO2 and a noncrystalline mullite phase; (2) the non-crystalline mullite phase is an important transitional phase towards equilibrium under subsolidus conditions. In the experimental conditions used the amount of the non-crystalline phase varies by as much as about 15%. This phase is of great importance in the mechanisms of reaction sintering between ZrO2 · SiO2 and αAl2O3.
47 citations
TL;DR: Aromatic and aliphatic oximes are protonated under methane or isobutane chemical ionization conditions in this paper, and the structural identity of the [MHH2O]-˙ ions with nitrilium cations is established by the mass analysed ion kinetic energy method after collisional activation.
Abstract: Aromatic and aliphatic oximes are protonated under methane or isobutane chemical ionization conditions. The structural identity of the [MHH2O]+˙ ions with nitrilium cations is established by the mass analysed ion kinetic energy method after collisional activation. The results also show the stereospecific nature of the transposition in the gas phase.
36 citations
TL;DR: The structure of the major adduct ions formed in ammonia chemical ionization of thirteen aliphatic and aromatic ketones have been studied by mass analysed ion kinetic energy spectrometry as discussed by the authors.
Abstract: The structures of the major adduct ions formed in ammonia chemical ionization of thirteen aliphatic and aromatic ketones have been studied by mass analysed ion kinetic energy spectrometry. The [M+NH3+H]+ ion is shown to have a protonated carbinolamine structure, [M+2NH3+H]+ to be a protonated carbinolamine with hydrogen-bonded ammonia and [2M+NH3+H]+ to be, at least in part, a protonated carbinolamine with hydrogen-bonded ketone. These structures may imply a nucleophilic addition of ammonia at the carbonyl of the ketone-ammonium ion complex. An unusual hydroxy migration is seen in the internal rearrangement of the [2M+NH3+H]+ ion leading to the formation of a protonated imine.
31 citations
TL;DR: In this paper, it was shown that the kinetic energy release for CO loss from phenol does not decrease as the ion accelerating voltage is decreased, in fact, an increase is observed which is attributed, at least in part, to greater discrimination against off-axis ions at low voltage.
Abstract: It is shown that, contrary to a recent report, the kinetic energy release for CO loss from phenol does not decrease as the ion accelerating voltage is decreased. In fact, an increase is observed which is attributed, at least in part, to greater discrimination against off-axis ions at low voltage. The kinetic energy release data do not demand the tautomerization of ionized phenol before decarbonylation.
19 citations
TL;DR: In this paper, it was shown experimentally that persistent photoconductivity occurs in an amorphous germanium film, submitted to laser irradiation, and a strong electron-lattice coupling around the dangling bonds present in the material may explain this phenomenom qualitatively.
9 citations
TL;DR: In this article, the electronic structure of sputtered-deposited PtO 2 films was probed using double-beam photoemission, optical absorption and electrical resistivity measurements.
6 citations
01 Jan 1980
5 citations
TL;DR: In this article, a critical slowing down is shown of the Soret-driven instability after a perturbation, described by ''ensuremath{\tau}={\ensureMath{\tAU}}_{0}{\ensure-math{\epsilon}}^{\ENSuremath{-}1},'' and the time relaxation is correlated to all the parameters of this problem such as the Prandtl number, the Schmidt number, and Soret coefficient.
Abstract: A critical slowing down is shown of the time relaxation in the Soret-driven instability after a perturbation, described by $\ensuremath{\tau}={\ensuremath{\tau}}_{0}{\ensuremath{\epsilon}}^{\ensuremath{-}1}$, $\ensuremath{\epsilon}=\frac{({N}_{\mathrm{Ra}}\ensuremath{-}{{N}_{\mathrm{Ra}}}^{\mathrm{crit}})}{{{N}_{\mathrm{Ra}}}^{\mathrm{crit}}}$, and ${\ensuremath{\tau}}_{0}$ is calculated exactly, i.e., with no extra assumptions other than a Boussinesquian and Newtonian fluid; ${\ensuremath{\tau}}_{0}$ is correlated to all the parameters of this problem such as the Prandtl number, the Schmidt number, the Soret coefficient, and the solute Rayleigh number.
3 citations
TL;DR: In this paper, a pre-reaction of triphenylsilane with the residual water in the solvent has been performed in an anhydrous medium and the activation parameters have been measured.
Abstract: Condensation of triphenylsilane with isopropanol in presence of isopropoxide has been studied in anhydrous medium and the activation parameters have been measured Dehydration of the medium has been obtained by means of a pre-reaction of triphenylsilane with the residual water in the solvent In this medium the reaction is extremely slow, moreover, it is inhibited by silanol whose effect would lower the actual catalyst concentration