Materials Literature
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We study the effect of physical aging on the mechanical properties of a model polymer glass using molecular dynamics simulations. The creep compliance is determined simultaneously with the structural relaxation under a constant uniaxial load below yield at constant temperature. The model successfully captures universa…
Worth their weight in gold: Au/CeO2 nanoparticles are a highly active catalyst for the hydrosilylation of a large variety of unsaturated compounds with high chemo- and regioselectivity. To understand the nature of the catalytic active sites, AuI and AuIII phosphine-free stable organogold complexes and their supported…
Single-crystalline arrays of PbS, PbSe, and PbTe nanowires (Figure: PbS) with diameters ranging from 40-200 nm and lengths up to 100 μm have been synthesized by a chemical vapor transport approach. Electrical and thermal characterization was performed to investigate their potential as thermoelectric materials. Compare…
Abstract BACKGROUND: Vegetable oil‐based polyols are a new class of renewable materials. The structure of oil‐based polyols is very different from that of petrochemical polyols, and it is closely related to the structure of oils. The objective of this work was to analyze the structural heterogeneity of soy‐based polyo…
Carbon dioxide reforming of methane (CDRM) was studied over a variety of ZrO 2 -, ceria-doped ZrO 2 -, and CeO 2 –ZrO 2 -supported Ni catalysts. Different techniques were used to prepare supports material having different physicochemical properties, and a correlation was established to show the importance of a robust…
We report theoretical results predicting the atomic manipulation of a silver atom on a Si(001) surface by a scanning probe tip, and providing insight into the manipulation phenomena. A molecular mechanics technique has been used, the system being described by a quantum chemistry method for the short-range interactions…
This paper reports a study of the influence of the step at a silicon surface under an uniaxial tensile stress, using an empirical potential. Our aim was to find conditions leading to nucleation of dislocations from the step. We obtained that no dislocations could be generated with such conditions. This behaviour, diff…
The stability of the perfect screw dislocation in silicon has been investigated using both classical potentials and first-principles calculations. Although a recent study by Koizumi et al . stated that the stable screw dislocation was located in both the 'shuffle' and the 'glide' sets of {111} planes, it is shown that…
The role of a simple surface defect, such as a step, for relaxing the stress applied to a semiconductor, has been investigated by means of large scale first principles calculations. Our results indicate that the step is the privileged site for initiating plasticity, with the formation and glide of 60$^\circ$ dislocati…
The properties of perfect screw dislocations have been investigated for several zinc-blende materials such as diamond, Si, $β$-SiC, Ge and GaAs, by performing first principles calculations. For almost all elements, a core configuration belonging to shuffle set planes is favored, in agreement with low temperature exper…
The high lattice mismatched SiC/Si(001) interface was investigated by means of combined classical and ab initio molecular dynamics. Among the several configurations analyzed, a dislocation network pinned at the interface was found to be the most efficient mechanism for strain relief. A detailed description of the disl…
The homogeneous shear of the {111} planes along the <110> direction of bulk silicon has been investigated using ab initio techniques, to better understand the strain properties of both shuffle and glide set planes. Similar calculations have been done with three empirical potentials, Stillinger-Weber, Tersoff and EDIP,…
Using first principles, classical potentials, and elasticity theory, we investigated the structure of a semiconductor/semiconductor interface with a high lattice mismatch, SiC/Si(001). Among several tested possible configurations, a heterostructure with (i) a misfit dislocation network pinned at the interface and (ii)…
Abstract The crystalline structure of poly( L ‐lactide) (PLLA) have been found to quite depend on the crystallization temperatures ( T c s), especially in the range of 100−120°C, which is usually used as the crystallization temperature for the industrial process of PLLA. The analysis of wide‐angle X‐ray diffraction an…
We describe the process of F\"orster transfer between semiconductor nanoparticles in the presence of a metal subsystem (metal nanocrystals). In the presence of metal nanocrystals, the F\"orster process can become faster. The enhancement of F\"orster transfer occurs due to the effect of plasmon-assisted amplification o…
Abstract Transparent samples of cubic (8 mol % yttria) and tetragonal (3 mol % yttria) zirconia were prepared from nanometric powders by the pulsed electric current sintering process. The crystallite size of the resulting dense samples was about 50 nm in both cases. The consolidation pressure had a positive effect on…
A new type of lightly crosslinked shape-memory polymer that contains reversibly associating side-groups is reported. H-bonding interactions stabilize mechanically strained states at low temperatures. The materials' shape recovery rate exhibits Arrhenius-like temperature dependence due to the dynamics of H-bond dissoci…
A highly efficient approach for metal filling of TiO2 nanotube layers is demonstrated. Electrochemical self-doping is used to switch selectively the bottom of TiO2 nanotubes into a conductive state. Subsequent metal electrodeposition therefore starts at the tube bottom and continues in a homogenous and controllable ma…
Array of light: Nanostructured arrays of NaMF4 (M=rare earth metal) can be prepared by a hydrothermal method. The arrays consist of nanoparticles with well-controlled morphologies (tubes, disks, or rods), phases (cubic or hexagonal), and sizes (80–900 nm). Multicolor upconversion fluorescence is realized in arrays of…
Polycarbonate is one of the most widely used engineering plastics because of its superior physical, chemical, and mechanical properties. Understanding the biodegradation of this polymer is of great importance to answer the increasing problems in waste management of this polymer. Aliphatic polycarbonates are known to b…