Výsledky vyhledávání - "A.P Esculcas"

Structural studies of dilute lacunar solid solutions of PO43− ions in β-barium orthotitanate, β-Ba2TiO4

Autor: Pierre Tarte, A.P. Esculcas, André Rulmont, F. Wijzen, B. Gilbert, João Rocha

Publikováno v: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 55:325-332

In the monoclinic Ba 2 TiO 4 structure, it is possible to substitute a small amount of TiO 4 tetrahedra by PO 4 3− ions either by keeping constant the number of cations or by forming lacunar phases. This paper deals with the particular case of the

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::bc0a5853aafd7959b83e3bf7e9277d5d
https://doi.org/10.1016/s1386-1425(98)00188-7

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Synthesis and characterization of catalyst supports with composition xSiO2–xAlPO4–(100–2x)TiO2

Autor: João Rocha, Benoit Koch, F. Wijzen, A. Rulmont, A.P. Esculcas

Publikováno v: Materials Research Bulletin. 33:1667-1680

Several xSiO 2 –xAlPO 4 –(100–2x)TiO 2 catalyst supports were investigated with regard to their structural and textural properties. Their textural properties were found to depend on their chemical composition. Low titania content (5 mol%) led t

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::9edb45ff0fc3ed35cab5612980b07e56
https://doi.org/10.1016/s0025-5408(98)00173-1

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Texture and Structure of Amorphous Co-Precipitated Silica-Aluminum Phosphate Catalyst Supports

Autor: João Rocha, M. Liégeois-Duyckaerts, A. Rulmont, Benoit Koch, A.P. Esculcas, F. Wijzen

Publikováno v: Journal of Catalysis. 177:96-104

A series of co-precipitated silica-aluminum phosphate containing between 0 and 100 mol% silica were synthesized by a coprecipitation technique and characterized by various methods. X-ray fluorescence analysis shows that the P/Al molar ratio in the so

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::e6d2a5896ead6937fc6d3d9bccc61ac8
https://doi.org/10.1006/jcat.1998.2093

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Effect of extra-lattice aluminium species on the activity, selectivity and stability of acid zeolites in the liquid phase isomerisation of α-pinene

Autor: Joaquim Vital, A.P. Esculcas, João Rocha, A. Severino, L.S. Lobo

Publikováno v: Applied Catalysis A: General. 142:255-278

The liquid phase isomerisation of α-pinene was studied on a number of zeolite catalysts at 150°C. The primary reaction products were camphene, tricyclene and p -menthadienes. Catalyst samples with lattice Si/Al ratios ranging from 1.46 to ca. 200 w

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::64f3d0a7cda38fd39111e38d66939bcf
https://doi.org/10.1016/0926-860x(96)00091-9

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Structural characterization of glassy phases in the system Na2O-Ga2O3-P2O5 by MAS and solution NMR and vibrational spectroscopy: II. Structure of the phosphate network

Autor: João Rocha, André Rulmont, F. Wijzen, Zelimir Gabelica, Gabriel Llabres, B. Gilbert, A. Belkebir, P Berthet, A.P. Esculcas

Publikováno v: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy. 56(3)

The structure of the phosphate network of glasses in the system Na2O–Ga2O3–P2O5 has been investigated as a function of the Na/Ga molar ratio and the phosphate composition corresponding to a mono, di, tri, tetra and meta phosphate stoichiometry. T

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::9f41e5c2cff6c83fc0980204a5278df5
https://pubmed.ncbi.nlm.nih.gov/10794458

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Structural characterization of glassy phases in the system Na2O-Ga2O3-P2O5 by MAS-NMR, EXAFS and vibrational spectroscopy. I. Cations coordination

Autor: Gabriel Llabres, B. Gilbert, A.P Esculcas, João Rocha, S. Poisson, P Berthet, Zelimir Gabelica, F. Wijzen, André Rulmont, A. Belkebir

Publikováno v: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy. 56(3)

The cationic coordinations of phosphate based gallium sodium glasses in the system Na2O-Ga2O3-P2O5 have been studied by several techniques (71Ga and 23Na MAS-NMR, EXAFS and vibrational spectroscopies) in order to study the relationship between the st

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::37cbeb5add8c7e498cc8ba6ff0925093
https://pubmed.ncbi.nlm.nih.gov/10794457

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The nature of the acid sites in mesoporous MCM-41 molecular sieves

Autor: Ralf Schmidt, A. Liepold, K. Roos, A.P. Esculcas, Andreas Philippou, Wladimir Reschetilowski, Michael W. Anderson, João Rocha, Michael Stöcker

The objective of this presentation is to give a characterization of aluminosilicate MCM-41, in particular with respect to acidity and the nature of the acid sites. 29 Si MAS NMR spectra of MCM-41 closely resemble those of amorphous silica, suggesting

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::8cf562c5b9e647648888706efcd38de3
https://doi.org/10.1016/s0167-2991(97)80584-8

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13C solid-state nuclear magnetic resonance and Fourier transform infrared studies of the thermal decomposition of cork

Autor: A. J. Ferrer Correia, C. Pascoal Neto, Ana M. Gil, João Rocha, A.P. Esculcas, Ivonne Delgadillo, J. D. Pedrosa De Jesus, Sílvia M. Rocha, Nereida Cordeiro

Publikováno v: Scopus-Elsevier
Repositório Científico de Acesso Aberto de Portugal
Repositório Científico de Acesso Aberto de Portugal (RCAAP)
instacron:RCAAP

The thermal decomposition of cork has been studied by Fourier transform infrared (FTIR) spectroscopy and 13C solid-state nuclear magnetic resonance (NMR) spectroscopy with cross-polarization and magic-angle spinning (CP-MAS), high-power 1H decoupling

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e2e268c516e8f73c76df8d7d2c0093ae
https://pubmed.ncbi.nlm.nih.gov/7773647

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