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101.
V. Aviyente M. Iraqi T. Peres C. Lifshitz 《Journal of the American Society for Mass Spectrometry》1991,2(2):113-119
Ion clusters were formed in a temperature-variable high-pressure ion source from neat acetone and acetone/water mixtures and subjected to tandem mass spectrometry studies-unimolecular and collisionally activated mass-analyzed ion kinetic energy spectroscopy. The predominance of water loss from H+(H20)(A) l=3, where A = acetone, suggests that the solvation sphere around H3O+ does not close at l = 3, contrary to the case of acetonitrile or dimethyl ether. The results may be interpreted in terms of suggested ion structures which involve isomerization enroute to dissociation. The virtual absence of H/D scrambling in the collisionally activated dissociation of H3O+(DA)3, DA =acetone-d 6, and of D3O+(A)3 means that if enolization takes place, it is a rate-determining step in an irreversible isomerization. The stability of H+(H2O)(A)3 is a dominant factor in the observation of acetone loss from H+(H20)(A)4. 相似文献
102.
Yuval Peres Serguei Popov Perla Sousi 《Bulletin of the Brazilian Mathematical Society》2013,44(4):841-867
Let µ1,...,µ k be d-dimensional probabilitymeasures in ? d with mean 0. At each time we choose one of the measures based on the history of the process and take a step according to that measure. We give conditions for transience of such processes and also construct examples of recurrent processes of this type. In particular, in dimension 3 we give the complete picture: every walk generated by two measures is transient and there exists a recurrent walk generated by three measures. 相似文献
103.
M. Peres A. Cruz M.J. Soares A.J. Neves T. Monteiro K. Lorenz E. Alves 《Superlattices and Microstructures》2006,40(4-6):537
Eu ions were incorporated into AlN thin films using ion implantation, and the influence of the post-implant annealing ambient on structural and optical properties was investigated. Eu is incorporated into lattice sites which are slightly displaced from the substitutional Al sites. When compared with the as-implanted sample the near-substitutional ion fraction is reduced due to the thermal annealing in different atmospheres. The AlN crystal quality does not change with different annealing conditions, but sensitive defect-related emission bands are developed under different annealing temperatures. Eu3+ optical activation is detected for all the annealed samples. No spectral changes are observed for the shape of the intra- transition, suggesting that a similar site symmetry is preserved even when a slight displacement from the substitutitional site of the Eu3+ ions occurs. The role of the annealing conditions on the spectral position and thermal quenching of the transition is discussed. 相似文献
104.
105.
Rafael Silveira Peres Eduardo Cassel Carlos Arthur Ferreira Denise Schermann Azambuja 《Surface and interface analysis : SIA》2014,46(1):1-6
This paper reports an investigation into the use of condensed black wattle tannin as an environmental friendly sealer after zinc phosphating of carbon steel. In order to verify the sealer efficiency against corrosion, electrochemical impedance spectroscopy, potentiodynamic polarisation and salt spray tests were performed. To verify the pore modifications and phase compositions, SEM, electron dispersive spectroscopy and X‐ray diffraction analysis were carried out. The influence of the sealer on the adherence of finishing coatings was analysed. The results show that the tannin/sealer did not affect the final coating adhesion and improved the corrosion resistance of sealed samples. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
106.
Asher Peres 《Foundations of Physics》2006,36(1):1-18
The city of lions. Beaulieu-sur-Dordogne. The war starts. Drôle de guerre. Going to work. Going to school. Fleeing from village to village. Playing cat and mouse. The second landing. Return to Beaulieu. Return to Paris. Joining the boyscouts. Learning languages. Israel becomes independent. Arrival in Haifa. Kalay high school. Military training. The Hebrew Technion in Haifa. Relativity. Asher Peres. Metallurgy. Return to France. Escape from jail. Aviva.I am the cat who walks by himself, and all places are alike to me.Rudyard KiplingI am grateful to all those who contributed to this Festschrift which celebrates my 70th birthday and therefore the beginning of my eighth decade. In the Jewish religion, there is a prayer, “she-hehhyanu” to thank the Lord for having kept us alive and let us reach this day. I am an atheist and I have no Lord to thank, but I wish to thank many other people who are no longer alive and who helped me reach this point. 相似文献
107.
Yuval Peres 《Communications in Mathematical Physics》1996,177(2):417-434
We show that sample paths of Brownian motion (and other stable processes) intersect the same sets as certain random Cantor sets constructed by a branching process. With this approach, the classical result that two independent Brownian paths in four dimensions do not intersect reduces to the dying out of a critical branching process, and estimates due to Lawler (1982) for the long-range intersection probability of several random walk paths, reduce to Kolmogrov's 1938 law for the lifetime of a critical branching process. Extensions to random walks with long jumps and applications to Hausdorff dimension are also derived. 相似文献
108.
For integers d > 1 and arbitrary 1 ? α ? d, α-products in d-fold Cartesian products are produced by probabilistic methods. Some explicit constructions are given by solutions of instances of the Turán problem for graphs. 相似文献
109.
Fernanda Peres FerreiraEduardo Henck Marturano Carlos Alexandre CarolloDionéia Camilo Rodrigues de Oliveira 《Tetrahedron letters》2011,52(2):297-299
A novel labdane diterpene was isolated from the plant Acritopappus longifolius. The structure of this compound was established by 1D- and 2D-nuclear magnetic resonance spectroscopic techniques and mass spectrometry data. N-Methyl-4-hydroxy-trans-proline, stigmasterol-3-O-β-d-glycoside, and the flavonoids quercetin, luteolin, kaempferol, and rutin were also isolated. 相似文献
110.
An all-solid-state potentiometric electronic tongue with 36 polymeric membranes has been used for the first time to detect gliadins, which are primarily responsible for gluten intolerance in people suffering from celiac disease. A linear discriminant model, based on the signals of 11 polymeric membranes, selected from the 36 above using a stepwise procedure, was used to semi-quantitatively classify samples of a “Gluten-free” foodstuff (baby milked flour), previously contaminated with known amounts of gliadins (<10, 20-50 or >50 mg/kg), as “Gluten-free”, “Low-Gluten content” or “Gluten-containing”. For this food matrix, the device had sensitivity towards gliadins of 1-2 mg/kg and overall sensitivity and specificity of 77% and 78%, respectively. Moreover, the device never identified an ethanolic extract containing gliadins as “Gluten-free”. Finally, the system also allowed distinguishing “Gluten-free” and “Gluten-containing” foodstuffs (15 foods, including breads, flours, baby milked flours, cookies and breakfast cereals) with an overall sensitivity and specificity greater than 83%, using the signals of only 4 selected polymeric membranes (selected using a stepwise procedure). Since only one “Gluten-containing” foodstuff was misclassified as “Gluten-free”, the device could be used as a preliminary tool for quality control of foods for celiac patients. 相似文献