The photoluminescence of the diverse nanostructures of nonstoichiometric ZnO grown via carbothermal reduction at 900°C was investigated. Various formations of different structures like wires, rods, tubes and tetr...
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ISBN:
(纸本)0878494715
The photoluminescence of the diverse nanostructures of nonstoichiometric ZnO grown via carbothermal reduction at 900°C was investigated. Various formations of different structures like wires, rods, tubes and tetrapods resulted from the inhomogeneity of the boundary diffusion layer associated with vapor current induced in the set-up. The band gap emission of these structures was observed at around 390 nm, which corresponds to energy of 3.20 eV. The study was extended to measure changes of crystal habit of ZnO nanostructures in terms of its fractal dimension.
First-principles calculations were employed to elucidate the origin of adsorption-induced surface stresses in alkanethiolate self-assembled monolayers on an Au(111) surface. Our results suggest a mechanism that accoun...
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First-principles calculations were employed to elucidate the origin of adsorption-induced surface stresses in alkanethiolate self-assembled monolayers on an Au(111) surface. Our results suggest a mechanism that accounts for the huge relief of the tensile stress compared to the bare surface in terms of a local rearrangement of surface Au atoms accompanying charge removal from the surface towards the Au-S bond. A purely interadsorbate interaction model is shown to be inconsistent with the anisotropy and the magnitude of the calculated stress.
This work describes a simple two-step method for grafting thermoresponsive amine-terminated poly(N-isopropylacrylamide) brushes to thin films of freshly-etched porous Si. Grafting is achieved by pre-hydrosilylation of...
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Amorphous sputter-deposited NiTi thin films were subjected to pulsed, melt-mediated laser crystallization techniques to engineer their microstructure. The effects of laser processing of pre-heated films are examined. ...
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Amorphous sputter-deposited NiTi thin films were subjected to pulsed, melt-mediated laser crystallization techniques to engineer their microstructure. The effects of laser processing of pre-heated films are examined. Laser processing of films at an elevated temperature has a significant effect on the rate with which solidification occurs and therefore may be used as an added parameter to control the resulting microstructure. It is seen that the temperature at which processing is carried out has significant implications for the resulting phase and microstructure, and therefore mechanical properties. Furthermore, the microstructural effects of varying incident laser energy density are examined via atomic force microscopy (AFM), scanning electron microscopy (SEM) and x-ray diffraction (XRD), and mechanical/shape memory properties are characterized via nanoindentation.
In cartilage tissue regeneration, it is important that an implant inserted into a defect site can maintain its mechanical integrity and endure stress loads from the body, in addition to being biocompatible and able to...
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Density functional theory can accurately predict chemical and mechanical properties of nanostructures, although at a high computational cost. A quasicontinuum-like framework is proposed to substantially increase the s...
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Ceramic porous structures are specially indicated for filters for molten metals, hot gases, thermal protection systems and heat exchangers, due their high permeability, good retention capacity, low density and high th...
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ISBN:
(纸本)9788880800842
Ceramic porous structures are specially indicated for filters for molten metals, hot gases, thermal protection systems and heat exchangers, due their high permeability, good retention capacity, low density and high thermal insulation. This work describes the research carried out on mechanical properties of two different types of a commercial porous ceramic material (10 and 40 ppi). The ceramic material was characterized in terms of microstructural aspects, crystalline phases, density, porosity, strength and thermal shock behaviour. The results have indicated that the strength of the material remain practically constant, regardless of the temperature. The fracture analyses indicated that the fracture is normally caused by the presence of microcracks and also by the presence of a large amount of pores in the ceramic filaments.
The reduction of Cu2O islands on Cu(100) surfaces under vacuum annealing leads to the formation of surface craters on the substrate surface surrounding the reducing oxide islands. These craters exhibit growth instabil...
The reduction of Cu2O islands on Cu(100) surfaces under vacuum annealing leads to the formation of surface craters on the substrate surface surrounding the reducing oxide islands. These craters exhibit growth instability characterized by increased slope of both the inner and outer facets of the crater rims. We suggest that the crater formation and the growth instability are related to the homoepitaxial growth of Cu adatoms dislodged from the reducing Cu2O islands. Incorporation of such atomic processes in kinetic Monte Carlo simulations reproduces the morphological features of the experimentally observed craters.
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