Encontrados 30 documentos, a visualizar página 1 de 3
Experimental and theoretical studies of the second- and third-order NLO propert...
Silva, Pedro S. Pereira; Ouazzani, Hasnaa El; Pranaitis, Mindaugas; Silva, Manuela Ramos; Arranja, Cláudia T.; Sobral, Abilio J. F. N.A new semi-organic compound, 6-aminoquinolinium iodide monohydrate (I), has been synthesized and characterized by single crystal X-ray diffraction, UV–vis absorption and fluorescence spectroscopy and nonlinear optical (NLO) measurements. The second- and third-order NLO responses were investigated with the second- and third-harmonic Maker fringes techniques, carried out on thin films at a fundamental wavelength ...
Audit Trail CChit : specification and implementation
Paixão, José Miguel RibeiroEstágio realizado na ALERT Life Sciences Computing, S. A. e orientado pelo Eng.º Rui Moreira Spratley Pinto da Silva ; Tese de mestrado integrado. Engenharia Informática e Computação. Faculdade de Engenharia. Universidade do Porto. 2008
Automatic collection of biographical data on the web for public personalities
Paixão, José Pedro Azeredo Lopes de MouraTese de mestrado integrado. Engenharia Informática e Computação. Faculdade de Engenharia. Universidade do Porto. 2010
5β,6β-Epoxy-17-oxoandrostan-3β-yl acetate and 5β,6β-epoxy-20-oxopregnan-3β-yl a...
Pinto, Rui M. A.; Salvador, Jorge A. R.; Paixão, José A.In the title compounds, C21H30O4, (I), and C23H34O4, (II), respectively, which are valuable intermediates in the synthesis of important steroid derivatives, rings A and B are cis-(5β,10β)-fused. The two molecules have similar conformations of rings A, B and C. The presence of the 5β,6β-epoxide group induces a significant twist of the steroid nucleus and a strong flattening of the B ring. The different C17 subst...
A new ranking path algorithm for the multi-objective shortest path problem
Paixão, José Manuel; Santos, José LuisIn this paper, we present a new algorithm for solving the multi-objective shortest path problem (MSPP) which consists of finding all the non-dominated paths between two nodes s and t (ND s-t paths), on a network where a multiple criteria function is defined over the set of arcs. The main feature of the algorithm is that, contrarily to the previous most efficient approaches for the MSPP, not all of the ND sub-pa...
Propeller-like Conformation of Diphenylacetic Acid
Silva, Manuela; Cardoso, Cláudia; Beja, Ana; Paixão, José; Domingos, SérgioAbstract Crystal structure of diphenylacetic acid has been solved by X-ray diffraction. The crystals are monoclinic, space group P21/c, with a = 12.254(4) Å, b = 7.2260(8) Å, c = 17.521(4) Å, ß = 133.38(1)°, Mr = 212.24, V = 1127.6(5) Å3, Z = 4 and R = 0.045. A strong hydrogen bond links the molecules in dimers. The dimers are connected by weaker C–H···p and p···p interactions. A calculation was performed for ...
Solving Public Transit Scheduling Problems
Mesquita, Marta; Moz, Margarida; Paias, Ana; Paixão, José; Pato, Margarida Vaz; Respício, AnaOperational planning within public transit companies has been extensively tackled but still remains a challenging area for operations research models and techniques. This phase of the planning process comprises vehicle scheduling, crew scheduling and rostering problems. In this paper, a new integer mathematical formulation to describe the integrated vehicle-crew-rostering problem is presented. The method propos...
Chemistry of Diazafulvenium Methides in the Synthesis of Functionalized Pyrazoles
Melo, Teresa M. V. D. Pinho e; Nunes, Cláudio M.; Soares, Maria I. L.; Paixão, José A.; Beja, Ana Matos; Silva, Manuela RamosThe chemistry of diazafulvenium methides generated by the thermal extrusion of sulfur dioxide from 2,2-dioxo-1H,3H-pyrazolo[1,5-c] [1,3]thiazoles is described. The diazafulvenium methides unsubstituted at C-7 participate in [8π + 2π] cycloadditions giving pyrazolo-annulated heterocycles resulting from the addition across the 1,7-position. 1-Methyl-diazafulvenium methides and 7,7-dimethyl-diazafulvenium methides...
Labelling methods for the general case of the multi-objective shortest path pro...
Paixão, José Manuel; Santos, José LuisThis paper is devoted to the study of labelling techniques for solving the multi-objective shortest path problem (MSPP) which is an extension of the shortest path problem (SPP) resulting from considering simultaneously more than one cost function (criteria) for the arcs. The generalization of the well known SPP labelling algorithm for the multiobjective situation is studied in detail and several different versi...
Ranking multiobjective shortest paths
Martins, Ernesto Queirós; Paixão, José Manuel; Rosa, Mário Silva; Santos, José LuisThis paper is concerned with the ranking of multi-objective shortest paths accordingly to an order relation verifying certain conditions such is the case, for instance, of the lexicographic order. We present a new labelling algorithm that makes use of shortest deviation paths for obtaining the set of Pareto solutions for the multi-objective shortest path problem. The computational experience reported at the end...
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