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971.
Débora Lopes Jorge Sotomayor Ronaldo Garcia 《Bulletin of the Brazilian Mathematical Society》2014,45(3):453-483
The topological structure of the lines of principal curvature, the umbilic and partially umbilic singularities of all tridimensional ellipsoids of ?4 is described. 相似文献
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Effect of hexyl substituent groups on photophysical and electrochemical properties of the poly[(9,9‐Dioctyluorene)−2,7‐diyl‐alt‐(4,7‐bis (3‐Hexylthien‐5‐Yl)−2,1,3‐Benzothiadiazole)−2′,2″‐diyl] 下载免费PDF全文
Daniel J. da Silva Herick G. Takimoto Karine C. C. Weber dos Santos Jarem R. Garcia Debora T. Balogh Shu Hui Wang 《Journal of Polymer Science.Polymer Physics》2016,54(19):1975-1982
The effect of the presence of hexyl group in thiophene on the photophysical and electrochemical properties of poly[(9,9‐dioctyluorene)?2,7‐diyl‐alt‐(4,7‐bis(3‐hexylthien‐5‐yl)?2,1,3‐benzothiadiazole)?2′,2″‐diyl] (F8TBT) is investigated. The copolymers present electron donor–acceptor architecture and are synthesized by Suzuki coupling reaction. The UV/Vis spectra show absorption maximum in the wavelength range of blue and orange, which are associated with different segments of the polymer backbone. Addition of hexyl substituent groups has a positive effect on the molar absorptivity and increases the emission and absorption intensities due to fluorene and thiophene‐benzothiadiazole‐thiophene (TBT) units, although an increment in the bandgap is observed. Cyclic voltammetry study of the polymer films reveal irreversible reduction and oxidation processes of the TBT units in the polymer chain and the HOMO and LUMO energy levels suggest ambipolar character for the polymers, while the electrochemical bandgaps are consistent with the absorbance measurements. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1975–1982 相似文献
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We apply the Riccati–Padé method and the Rayleigh–Ritz method with complex rotation to the study of the resonances of a one-dimensional well with two barriers. The model exhibits two different kinds of resonances and we calculate them by means of both approaches. While the Rayleigh–Ritz method reveals each set at a particular interval of rotation angles the Riccati–Padé method yields both of them as roots of the same Hankel determinants. 相似文献
977.
Fabrication,chemical modification,and topographical patterning of reactive gels assembled from azlactone‐functionalized polymers and a diamine 下载免费PDF全文
Megan M. Wancura Quinn Anex‐Ries Anna L. Carroll Ana Paola Garcia Pooja Hindocha Maren E. Buck 《Journal of polymer science. Part A, Polymer chemistry》2017,55(19):3185-3194
The work reported here demonstrates an approach to the fabrication of chemically reactive and topographically patterned hydrogels using the azlactone‐functionalized polymer poly(2‐vinyl‐4,4'‐dimethylazlactone) (PVDMA) and the hydrophilic diamine Jeffamine®. Gels were initially assembled in DMSO but can be subsequently transferred into aqueous media to form hydrogels. Spectroscopic characterization of assembled gels demonstrated that variation in the stoichiometric ratio of azlactones to amines during gel synthesis permits control over the extent of crosslinking in the gels. Residual azlactones not consumed during crosslinking can be exploited to further functionalize these gels with hydrophobic, hydrophilic, and macromolecular amines that influence the physicochemical properties of these materials in aqueous solvents. The surface and bulk of these gels can be differentially functionalized (i.e., different functional groups on the gel surface relative to the bulk) by taking advantage of different rates of diffusion of macromolecular amines versus small molecule amines into assembled gels. Finally, these azlactone‐functionalized gels can be topographically patterned with microwell arrays using a replica molding technique and chemically modified postfabrication with amine nucleophiles. This reactive approach to the fabrication of topographically patterned and chemically functionalized hydrogels offers a straightforward method for the rapid synthesis of micropatterned scaffolds of interest in a broad range of applications. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3185–3194 相似文献
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Aurelian Rotaru Marinela M. Dîrtu Cristian Enachescu Radu Tanasa Jorge Linares Alexandru Stancu Yann Garcia 《Polyhedron》2009,28(13):2531-2536
Motivated by the application of the First Order Reversal Curve (FORC) technique to obtain a distribution of like spin domains in the spin crossover complexes [FexM1−x(btr)2(NCS)2]·H2O with MII = Zn and Ni, we have performed Differential Scanning Calorimetry (DSC) experiments. We have measured the heat capacity in the heating and cooling modes and then calculated the enthalpy and the entropy variations at the phase transition. In the framework of an Ising-like model, we have converted the experimental thermal hysteresis into terms of physical parameters related to these compounds. We have also performed a statistical analysis of these parameters and concluded that the correlation between them increases with the dilution degree of these spin crossover complexes. 相似文献
979.
Jose Luis Valin Rivera J.M. Monteiro H.M. Lopes M.A.P. Vaz Francisco Palacios Edison Gonalves Gilberto Garcia del Pino Jorge Ricardo Prez 《Optics and Lasers in Engineering》2009,47(11):1139-1144
The purpose of this article is to study the application of the holographic interferometry techniques in the structural analysis of submarine environment. These techniques are widely used today, with applications in many areas. Nevertheless, its application in submarine environments presents some challenges. The application of two techniques, electronic speckle pattern interferometry (ESPI) and digital holography, comparison of advantages and disadvantages of each of them is presented. A brief study is done on the influence of water properties and the optical effects due to suspended particles as well as possible solutions to minimize these problems. 相似文献
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