Search results for " Alloys"
showing 10 items of 1469 documents
Self-assembled dimers with supramolecular chirality
2003
The possibilities to form dimeric capsules with supramolecular chirality from tetraurea calix[4]arenes composed of two different phenolic urea units are discussed in general and demonstrated experimentally for various selected examples.
Atomistic simulation of SrTiO3 and BaTiO3 (110) surface relaxations
2000
Abstract The (110) surface relaxations were calculated for SrTiO 3 and BaTiO 3 perovskites in a cubic phase. Using a shell model, the positions of atoms in 16 near- surface layers placed atop a slab of rigid ions are calculated. The strong surface rumpling and induced surface dipole moments perpendicular to the surface are predicted for both the O-terminated and TiO-terminated surfaces.
Hybrid approach to surface roughness evaluation in multistage machining processes
2003
Abstract An assessment of surface quality in turned, ground and honed specimens is made by means of a computer-based processing of digitised surface profiles. Three different methods of surface finish characterisation, i.e. statistical, fractal and neural network-based approaches are examined and compared. Correlations between some representative roughness parameters and the fractal dimension (D) values estimated were found. Consequently, they can be converted to their corresponding roughness parameters, i.e. Ra, Rz and RΔa. Finally, a set of parameters including the minimum surface finish data for machining of external cylindrical surfaces when using complex technological process, is propo…
Surface properties of valine-gramicidin A at the air-water interface
1996
Abstract Fluorescence microscopy, X-ray reflectivity and ellipsometry have been applied to the study of a monolayer of valine-gramicidin A (VGA) at the air-water interface to obtain insight into the conformation and orientation of VGA, and to clarify the shoulder observed in its π - A curve (12.5–16 mN m −1 , 240 – 175 A 2 molecule −1 ). At low molecular areas, the X-ray reflectivities are consistent with formation of a single layer of tubular-shaped dimers. Fluorescence microscopy yielded homogeneous pictures suggesting that on the macroscopic scale the shoulder cannot be attributed to domain formation. Thicknesses calculated from the ellipsometric isotherm are consistent with the X-ray da…
Theory of positronium momentum spectra at metallic surfaces
1986
Theoretical calculations of momentum distributions of positronium (Ps) atoms ejected from clean metal surfaces are presented and compared with recent experimental results. The authors find that the momentum dependence of the Ps-forming interaction significantly affects the shape of the spectra. They also show that, within the model, the energy distribution of Ps atoms does not vary directly with the density of electronic states just outside the surface.
Superparamagnetic γ-Fe2O3 nanoparticles with tailored functionality for protein separation
2007
Polymer coated superparamagnetic gamma-Fe(2)O(3) nanoparticles were derivatized with a synthetic double-stranded RNA [poly(IC)], a known allosteric activator of the latent (2-5)A synthetase, to separate a single 35 kDa protein from a crude extract which cross reacted with antibodies raised against the sponge enzyme.
High Temperature Corrosion Behaviour of Coated F17Ti Stainless Steel
1997
Nous avons etudie l'effet de revetements de chromine et d'alumine sur le comportement de l'acier inoxydable F17Ti. Les films ont ete formes a la surface de l'alliage par pyrolyse de la vapeur d'un precurseur organometallique (MOCVD). Cette technique permet egalement de preparer des oxydes d'elements de terres rares. Ceci nous a conduit a envisager la formation de couches barrieres dopees par un element actif, soit par depots successifs, soit par codeposition de chromine ou d'alumine et d'un oxyde de terre rare, suivi d'un traitement de recuit d'homogeneisation. Les revetements ainsi obtenus ont ete caracterises par microscopie electronique a balayage, microanalyse X, diffraction des rayons …
The mechanism of aquaporin inhibition by gold compounds elucidated by biophysical and computational methods
2017
The inhibition of water and glycerol permeation via human aquaglyceroporin-3 (AQP3) by gold(iii) complexes has been studied by stopped-flow spectroscopy and, for the first time, its mechanism has been described using molecular dynamics (MD), combined with density functional theory (DFT) and electrochemical studies. The obtained MD results showed that the most effective gold-based inhibitor, anchored to Cys40 in AQP3, is able to induce shrinkage of pores preventing glycerol and water permeation. Moreover, the good correlation between the affinity of the Au(iii) complex to Cys binding and AQP3 inhibition effects was highlighted, while no influence of the different oxidative character of the c…
Reshaping End-of-Life components by sheet hydroforming: An experimental and numerical analysis
2022
In this study, a numerical/experimental analysis is proposed to investigate the possibility of reshaping sheet metal-based End-of-Life (EoL) components using sheet Hydroforming (SHF). Returned EoL components are challenging to be reformed, they are usually characterised by high heterogeneity as there are localised thinning areas (caused by the original forming processes), and the overall formability is reduced with respect to the original flat sheet material. The reshaping route was replicated: a deep drawing process was adopted to impart a square feature; subsequently, SHF was performed. The capability of remove the deep drawn feature was analysed with varying Blank-holder force, oil press…
Solubilized liver extracellular matrix maintains primary rat hepatocyte phenotype in-vitro.
2015
Whole organ engineering and cell-based regenerative medicine approaches are being investigated as potential therapeutic options for end-stage liver failure. However, a major challenge of these strategies is the loss of hepatic specific function after hepatocytes are removed from their native microenvironment. The objective of the present study was to determine if solubilized liver extracellular matrix (ECM), when used as a media supplement, can better maintain hepatocyte phenotype compared to type I collagen alone or solubilized ECM harvested from a non-liver tissue source. Liver extracellular matrix (LECM) from four different species was isolated via liver tissue decellularization, solubil…