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61.
Rubber covered cylinders in rolling contact are studied in two cases; rolling over a flat surface and rolling over a groove. In the first case, two different finite element procedures are compared for the purpose of investigating if computational savings can be made when taking amplitude dependent effects into account by using a modified viscoelastic steady state rolling procedure. This procedure is compared with using a more expensive overlay method with an elastoplastic-viscoelastic material model. The two procedures and material models are shown two give equal results in the flat surface case. For the case of rolling over a groove, it is shown how the non-linear dynamic material characteristics of the rubber layer influence the rolling contact. The groove filling capacity of the rubber is shown to be strongly dependent on the material model. It is shown that amplitude dependent rubber materials have better ability to fill out contact surface irregularities such as a groove. 相似文献
62.
Modification of σ‐Donor Properties of Terminal Carbide Ligands Investigated Through Carbide–Iodine Adduct Formation
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Anders Reinholdt Prof. Dr. Tom Vosch Prof. Dr. Jesper Bendix 《Angewandte Chemie (International ed. in English)》2016,55(40):12484-12487
The terminal carbide ligands in [(Cy3P)2X2Ru≡C] complexes (X=halide or pseudohalide) coordinate molecular iodine, affording charge‐transfer complexes rather than oxidation products. Crystallographic and vibrational spectroscopic data show the perturbations of iodine to vary with the auxiliary ligand sphere on ruthenium, demonstrating the σ‐donor properties of carbide complexes to be tunable. 相似文献
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This paper presents a 3D topology optimization approach for designing shell structures with a porous or void interior. It is shown that the resulting structures are significantly more robust towards load perturbations than completely solid structures optimized under the same condi-tions. The study indicates that the potential benefit of using porous structures is higher for lower total volume fractions. Compared to earlier work dealing with 2D topology opti-mization, we found several new effects in 3D problems. Most notably, the opportunity for designing closed shells signifi-cantly improves the performance of porous structures due to the sandwich effect. Furthermore, the paper introduces improved filter boundary conditions to ensure a completely uniform coating thickness at the design domain boundary. 相似文献
68.
Ahmad Arouri Anders Højgaard Hansen Thomas Elmelund Rasmussen Ole G. Mouritsen 《Current Opinion in Colloid & Interface Science》2013,18(5):419-431
Colloidal and interfacial phenomena lie at the core of drug formulation, drug delivery, as well as drug binding and action at diseased sites, e.g., in cancer therapy. We review a class of liposome-based drug-delivery systems whose design and functional properties are intimately controlled by the stability of sub-micron structures, lipid-bilayer interfaces, and interfacially activated enzymes that can be exploited to target and deliver drugs. Moreover these drugs can themselves be special lipid molecules in the form of lipid prodrugs that both form the liposomal carrier as well as the substrate for endogenously upregulated lipases that turn the prodrugs into potent drugs precisely at the diseased site. 相似文献
69.
A one-step synthesis of the stable [4]helicenium dye, 1,13-dimethoxy-chromeno[2,3,4-kl]xanthenium hexafluorophosphate (DMCX+) from the readily available tris(2,6-dimethoxyphenyl)carbenium ion is reported. The crystal structure, the chemical stability, and dye properties of the DMCX+ helicenium system are described. 相似文献
70.
Jonas Örtegren Philippe Busson Ulf W. Gedde Anders Hult Anders Eriksson Mikael Lindgren 《Liquid crystals》2013,40(6):861-868
We report second harmonic generation in a ferroelectric liquid crystalline trimer and ferroelectric liquid crystalline dendrimers of first, second and third generation. Thin cells were filled with the compounds by capillary forces at elevated temperature, and cooled from the surface stabilized ferroelectric state to below the glass transition temperature, while kept in an electric field. The cone motion viscosity and the threshold electric field for unwinding of the helix axis of the chiral tilted smectic mesophases were studied separately at elevated temperature, and these data were used to optimize the preparation of the films. The measured response time was between 0.3 and 3ms, which corresponds to a cone motion viscosity between 0.5 and 50 Pa s. Second harmonic generation was studied both at elevated temperature with an electric field and at room temperature with and without electric field. The first generation dendrimer exhibited a strong increase in the second order non-linear optical response with time at room temperature. The d 23-coefficient of this dendrimer was approximately four times larger than for the other macromolecules and was 0.045 pm V-1. The relatively large d-coefficient of the first generation dendrimer is ascribed to crystallization, which improved the orientation of the molecular dipoles. 相似文献