Abstract: Nano-scale ordering may be revealed in transmission electron microscopy (TEM) by at least three techniques that will be presented in this work: selected area electron diffraction, conventional TEM and high-resolution TEM. Digital image processing is used to extract additional information from the high-resolution micrographs. The described methods are illustrated in a microstructural and compositional study of a 90%Pb(Mg1/3Nb2/3)O-3-10%PbTiO2 ceramic sample. High-resolution images reveal the presence of ordered compositional nano-domains, observable in two specific crystallographic orientations. Antiphase boundaries lying in the (111) planes separate them, while (100) and (111) facets separate the ordered domains from the disordered matrix.

Abstract: We have studied granular films consisting of nanoscale Ga droplets formed on GaAs films via a method of vacuum annealing to promote As evaporation. For temperatures and magnetic fields below the bulk Ga critical parameters, the samples are very sensitive towards external microwave radiation when two point voltage measurements are performed. Together with the observation of an oscillating magnetic field dependence of the voltage, a scenario in which the samples consist of Josephson-coupled loops seems to be the most likely one for explaining the obtained results.

Abstract: Titanate nanotubes were prepared via a hydrothermal treatment of TiO2 powders (Riedel De Haen) in a basic solution. Morphology and structure of the prepared samples were characterized by high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), XRD, FT-Raman spectroscopy, nitrogen sorption and DSC. The photocatalytic activity was evaluated by photocatalytic oxidation of rhodamine 6G. Trititanate nanotubes (TTNT) with inner pore diameters between 4 and 4.2 nm and surface areas up till 360 m(2)/g could be synthesized. The synthesis route was modified by introduction of a calcination step, by applying a lower hydrothermal temperature and microwave irradiation in order to increase the photocatalytic activity of the porous photoactive nanotubular materials. Calcination and a softer hydrothermal treatment led to the formation of anatase without affecting the surface area and nanotubular shape of the samples. In this way, the photocatalytic activity of the original trititanate nanotubes could be significantly increased. By making use of microwave assisted synthesis, the photocatalytic activity call also be increased due to the presence of anatase. However, by applying microwave synthesis, a different structure was obtained, nanoribbons (NR) instead of nanotubcs, resulting in a decrease in surface area and porosity.

Abstract: Nanoparticle charging in a capacitively coupled radio frequency discharge in argon is studied using a particle in cell Monte Carlo collisions method. The plasma parameters and dust potential were calculated self-consistently for different unmovable dust profiles. A new method for definition of the dust floating potential is proposed, based on the information about electron and ion energy distribution functions, obtained during the kinetic simulations. This approach provides an accurate balance of the electron and ion currents on the dust particle surface and allows us to precisely calculate the dust floating potential. A comparison of the obtained floating potentials with the results of the traditional orbital motion limit (OML) theory shows that in the presence of the ion resonant charge exchange collisions, even when the OML approximation is valid, its results are correct only in the region of a weak electric field, where the ion drift velocity is much smaller than the thermal one. With increasing ion drift velocity, the absolute value of the calculated dust potential becomes significantly smaller than the theory predicts. This is explained by a non-Maxwellian shape of the ion energy distribution function for the case of fast ion drift.

Abstract: The microstructure of a Co38Ni33Al29 ferromagnetic shape memory alloy was determined by conventional transmission electron microscopy (TEM), electron diffraction studies together with advanced microscopy techniques and in situ Lorentz microscopy. Rod-like precipitates, 1060 nm long, of hexagonal close-packed -Co were confirmed to be present by high-resolution TEM. The orientation relationship between the precipitates and B2 matrix is described by the Burgers orientation relationship. The crystal structure of the martensite obtained after cooling is tetragonal L10 with a (111) twinning plane. The magnetic domain structure was determined during an in situ cooling experiment using the Fresnel mode of Lorentz microscopy. While transformation proceeds from B2 austenite to L10 martensite, new domains are nucleated, leading to a decrease in domain width, with the magnetization lying predominantly along a single direction. It was possible to completely describe the relationship between magnetic domains and crystallographic directions in the austenite phase though complications existed for the martensite phase.

Abstract: Air pollution caused by the lime production industry has become a serious problem with potential effects to human health, especially in developing countries. Colombo is a city included in the Metropolitan Region of Curitiba (capital of Parana State) in South Brazil. In Colombo city, a correlation has been shown between the lime production and the number of persons who need respiratory treatment in a local hospital, indicating that the lime industry can cause deleterious health effects in the exposed workers and population. This research was conducted to deal firstly with the characterization of the size distribution and chemical compositions of particles emitted from lime manufacturing and subsequently to assess the deposition rate of inhaled dolomitic lime aerosol particles in the human respiratory tract. The elemental chemical composition and particle size of individual atmospheric particles was quantitatively elucidated, including low-Z components like C, N and 0, as well as higher-Z elements, using automated electron probe microanalysis. Information concerning the bulk composition is provided by energy-dispersive X-ray detection. The majority of the respirable particulate matter identified was composed of aluminosilicates, Ca-Mg oxides, carbon-rich particles, mixtures of organic particles and Ca-Mg carbonates, soot and biogenic particles. In view of the chemical composition and size distribution of the aerosol particles, local deposition efficiencies in the human respiratory system were calculated, revealing the deposition of CaO center dot MgO at extrathoracic, tracheobronchial and pulmonary levels. The results of this study offer evidence to the threat of the fine and coarse particles emitted from dolomite lime manufacturing, allowing policy-makers to better focus their mitigation strategies in an effective way, as well as to the dolomite producers for the purpose of designing and/or implementing improved emission controls.

Abstract: Motivated by the recent realization of graphene sensors to detect individual gas molecules, we investigate the adsorption of H2O, NH3, CO, NO2, and NO on a graphene substrate using first-principles calculations. The optimal adsorption position and orientation of these molecules on the graphene surface is determined and the adsorption energies are calculated. Molecular doping, i.e., charge transfer between the molecules and the graphene surface, is discussed in light of the density of states and the molecular orbitals of the adsorbates. The efficiency of doping of the different molecules is determined and the influence of their magnetic moment is discussed.

Abstract: The persistent current in two vertically coupled quantum rings containing few electrons is studied. We find that the Coulomb interaction between the rings in the absence of tunneling affects the persistent current in each ring and the ground-state configurations. Quantum tunneling between the rings alters significantly the ground state and the persistent current in the system.