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81.
Numerical integrations of a hypothetical radical chain reaction model have been performed for the pyrolysis of CH2ClCH3 which is known to be molecular. Analyses of the modelling results have led to a better understanding of the participation (or nonparticipation) of “dead” radicals in the self-inhibition of the radical chain reaction. Attention is focused on the fact that apparently slow elementary reactions still may have to be taken into account in a pyrolysis mechanism when they produce “dead” radicals which can accumulate. © John Wiley & Sons, Inc. 相似文献
82.
Selectivity–reactivity correlations are shown to support a biradical pathway for the gas phase thermal Diels–Alder reactions of cyclohexa-1,3-diene with substituted ethenes except for those involving a carbonyl group. 相似文献
83.
R. Teghil A. Santagata V. Marotta S. Orlando G. Pizzella A. Giardini-Guidoni A. Mele 《Applied Surface Science》1995,90(4):505-514
Laser-induced ablation was applied to thin film deposition from a tin selenide target. Diagnostic methods are applied to the characterization of the laser ablated plume. Emission from atomic and ionic excited states of tin and selenium dominates the total emission of the plasma plume with excitation temperatures up to 12 000 K. A high-speed ICCD camera has also been used to study three-dimensional plume propagation. Positive and negative cluster ions of bare tin, selenium and of the combined elements have been detected by laser mass-spectrometry of the plume. The growth of SnSe has been analysed by electrical and optical techniques. The effect of laser fluence on the plume and on the properties of the deposits has also been studied. The epitaxial growth of SnSe on several substrates is reported. 相似文献
84.
85.
D. Mele 《European Polymer Journal》1978,14(9):623-624
A rigid linear array of beads in a Newtonian fluid is used to model a rod-like macromolecule in a dilute solution. Following the work of Kotaka, an expression is obtained relating the intrinsic viscosity to the velocity gradient. Computed results are compared with the experimental results of Strömberg. 相似文献
86.
Favino TF Fronza G Fuganti C Fuganti D Grasselli P Mele A 《The Journal of organic chemistry》1996,61(25):8975-8979
The synthesis of the strong natural roast odorants 1 and 2 is achieved from the C-6 isomeric alcohols 16 and 21 via the acetylenic C-6 and C-7 amines 8 and 9. Key step in the process is the hydrolysis of the N-phenylacetamides 12 and 13 by means of immobilized penicillin acylase, which affords the 1-amino-4,5-diketones 14 and 15, spontaneously ring closing to 1 and 2. These latter compounds form inclusion complexes with beta-cyclodextrin, as demonstrated by NMR measurements in deuterated water and FAB-MS spectra. 相似文献
87.
Mele G Del Sole R Vasapollo G Marcì G Garcìa-Lopez E Palmisano L Coronado JM Hernández-Alonso MD Malitesta C Guascito MR 《The journal of physical chemistry. B》2005,109(25):12347-12352
Characterization of polycrystalline TiO(2) bare or porphyrin impregnated powders, used as photocatalysts for the degradation of 4-nitrophenol (4-NP) in aqueous suspension, was performed by time-resolved microwave conductivity (TRMC) measurements and electronic paramagnetic resonance (EPR) and X-ray photoelectron (XPS) spectroscopies. The presence of porphyrin sensitizers, as the metal-free or Cu [5,10,15,20-tetra (4-tert-butylphenyl)] porphyrin, impregnated onto the TiO(2) surface improved the photocatalytic activity of the bare TiO(2). TRMC measurements indicate that the number and lifetime of the photoinduced excess charge carriers increase in the presence of the macrocycles, and EPR and XPS spectroscopies support the mechanistic hypotheses based on the photoreactivity experiments. 相似文献
88.
89.
Andrea Mele Giuseppina Raffaini Fabio Ganazzoli Antonio Selva 《Journal of inclusion phenomena and macrocyclic chemistry》2002,44(1-4):219-223
The structure of gaseous charged host-guest adducts ofcyclodextrins (CDs) generated by mass spectrometry (MS) still requires to be addressed correctly,as these adducts could be true inclusion complexes or non-specific proton bound heterodimers(PBHs). The present theoretical study of inclusion complex vs. PBH of 5-methoxytryptammonium ion(5-MTA+) with -CD in vacuo by energy minimisation and moleculardynamics proved that the most stable forms of -CD/5-MTA+ non-covalent associationare inclusion complexes. PBHs evolved to genuine inclusion complexes with two differenthost-guest arrangements during MD runs. 相似文献
90.
Cristina Sottani Andrea Mele Donata Favretto Pietro Traldi 《Journal of mass spectrometry : JMS》1992,27(3):169-173
The structural characterization of the E and Z isomers of p-nitrophenyl-diazo tert-butyl sulphide has been achieved by means of different ionization methods (electron impact, fast atom bombardment, positive-ion chemical ionization) and collision experiments performed under different kinetic energy regimes (high- and low-energy collisions, angle-resolved mass spectrometry and energy-resolved mass spectrometry). The two compounds give rise to identical fragmentation patterns. Collision experiments, both at low energy and in the keV range at a scattering angle of 0°, in M+· species obtained by electron impact on the two isomers, do not show any significant differences; the same experiments performed with 8 keV ions at a scattering angle of 2° indicate a clear difference in the absolute abundances of the two main daughter ions. High-energy collisions of MH+ ions obtained by fast atom bombardment lead to different spectra at both 0° and 2° scattering angles, proving that the energy deposition in the preselected species is an important parameter. Low-energy collisions with argon of MH+ ions generated by positive-ion chemical ionization (NH4+) give rise to almost identical energy-resolved mass spectra, whereas the same experiments using helium as target gas lead to a clear distinction between the two isomers. 相似文献