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Alternating Binaphthyl−Thiophene Copolymers: Synthesis, Spectroscopy, and Photo...
Pina, J.; Melo, J. Seixas de; Burrows, H. D.; Maçanita, A. L.; Galbrecht, F.; Bünnagel, T.; Scherf, U.The synthesis and a comprehensive spectroscopic and photophysical study are presented of four alternating binaphthyl−oligothiophene copolymers (DP: 10−15 repeat units) in solution at room and low temperature and in the solid state (thin films). Detailed results are presented on absorption, emission, and triplet−triplet absorption spectra together with all relevant quantum yields (fluorescence, intersystem cross...
A comprehensive study of the spectral and photophysical properties of arylthiop...
Melo, J. Seixas de; Pina, J.; Rodrigues, L. M.; Becker, R. S.A series of conjugated oligomers with rigid (fused-ring) structure, consisting in different polycyclic aromatic hydrocarbons (PAHs) possessing a single thiophene unit, here designated as arylthiophenes, were investigated in solution. For presentation clarity, the compounds were organized in two different groups. The first group includes the compounds where one, two, three and four benzene rings are added to a t...
Analysis of residual stresses induced by dry turning of difficult-to-machine ma...
Outeiro, J. C.; Pina, J. C.; Saoubi, R. M'; Pusavec, F.; Jawahir, I. S.Critical issues in machining of difficult-to-cut materials are often associated with short tool-life and poor surface integrity, where the resulting tensile residual stresses on the machined surface significantly affect the component's fatigue life. This study presents the influence of cutting process parameters on machining performance and surface integrity generated during dry turning of Inconel 718 and auste...
Excited State Properties of Oligophenyl and Oligothienyl Swivel Cruciforms
Pina, J.; Melo, J. Seixas de; Burrows, H. D.; Galbrecht, F.; Bilge, A.; Kudla, C. J.; Scherf, U.A comprehensive study has been undertaken of the electronic spectral and photophysical properties of two oligophenyl (BPH and BPHF) and one oligothienyl (BTF) swivel cruciforms involving measurements of absorption, fluorescence, and phosphorescence spectra, quantum yields of fluorescence (phiF), phosphorescence (phiPh) and triplet formation (phiT), lifetimes of fluorescence (τF) and of the triplet state (τT), a...
Spectral and Photophysical Studies of Poly[2,6-(1,5-dioctylnaphthalene)]thiophenes
Pina, J.; Melo, J. Seixas de; Burrows, H. D.; Galbrecht, F.; Nehls, B. S.; Farrell, T.; Scherf, U.A complete spectroscopic and photophysical study of three alternating naphthalene-α-thiophene copolymers was undertaken in solution (room and low temperature) and in the solid state (thin films in a Zeonex matrix). The study comprises absorption, emission, and triplet−triplet spectra together with quantitative measurements of quantum yield (fluorescence, intersystem-crossing, internal conversion, and singlet ox...
Electronic spectral and photophysical properties of some p-phenylenevinylene ol...
Melo, J. Seixas de; Pina, J.; Burrows, H. D.; Di Paolo, R. E.; Maçanita, A. L.A comprehensive photophysical and spectroscopic study of a new class of p-phenylenevinylene oligomers (PPV-trimers) possessing different alkyl and alkyloxy sidechain substituents and different end groups (aldehyde, CC, phenylene and anthracene units) was undertaken in solution at room temperature (293 K), low temperature (77 K) and in thin films. The study comprises absorption, emission and triplet-triplet abso...
Photophysical Studies of α,ω-Dicyano-oligothiophenes NC(C4H2S)nCN (n = 1−6)
Pina, J.; Burrows, H. D.; Becker, R. S.; Dias, F. B.; Maçanita, A. L.; Melo, J. Seixas deThe photophysics of six oligothiophenes end-capped with cyano groups (CNαn) was investigated in solution at room and low temperature. The study comprises singlet−singlet and triplet−triplet absorption and emission spectra together with lifetimes and quantum yields for all the radiative and nonradiative processes. From the lifetimes and quantum yields, it was possible to extract the rate constants for all the pr...
Triplet-State and Singlet Oxygen Formation in Fluorene-Based Alternating Copoly...
Fonseca, S. M.; Pina, J.; Arnaut, L. G.; Melo, J. Seixas de; Burrows, H. D.; Chattopadhyay, N.; Alcácer, L.; Charas, A.; Morgado, J.; Monkman, A. P.Data are reported on the triplet states of a series of fluorene-based A-alt-B type alternating copolymers based on pulse radiolysis-energy transfer and flash photolysis experiments. From the pulse radiolysis experiments, spectra are given for eight copolymers involving phenylene, thiophene, benzothiadiazole, and oligothienylenevinylene groups. Quantum yields for triplet-state formation (ΦT) have been obtained b...
Spectral and Photophysical Studies on Cruciform Oligothiophenes in Solution and...
Pina, J.; Melo, J. Seixas de; Burrows, H. D.; Bilge, A.; Farrell, T.; Forster, M.; Scherf, U.The photophysical and spectroscopic properties of a new class of oligothiophene derivatives, designated as cruciform oligomers, have been investigated in solution (room and low temperature) and in the solid state (as thin films in Zeonex matrixes). The study comprises absorption, emission, and triplet−triplet absorption spectra, together with quantitative measurements of quantum yields (fluorescence, intersyste...
Oestrogen receptors in a case of hydrometra in a bitch
Payan-Carreira, R.; Pina, J.; Costa, M.; Seixas, F.; Pires, M.A.Hydrometra in the bitch is a rare occurence, and the underlying cause is not usually identified. More frequently, hydrometra is associated with cystic endometrial hyperplasia. In this case, the aspect of the uterine endometrium is modified by the degree of the cystic disease. We present here a case of hydrometra, in a bitch brought for consultation with complaints of anorexia, weakness, vomit and distress. Gros...
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