Search results for "Note"
showing 10 items of 10709 documents
Structure and dynamics of CaO films: A computational study of an effect of external static electric field
2017
Oxide films play a significant role in a wide range of industrial fields, mostly due to the thickness-dependent variation of their properties. Recently, it has been proposed based on the experimental study that carrier transport in CaO films proceeds via strong phonon excitations with a variable signal depending on the film thickness. In this paper, we report a detailed investigation in the frame of the density functional theory of structural and electronic properties of freestanding and Mo(100)-supported CaO films, as well as phonons therein, as functions of the film thickness and intensity of the external static electric field. Our calculations demonstrate that phonon frequencies negligib…
Influence of the filling factor on the spectral properties of plasmonic crystals
2006
Plasmonics crystals (PCs) comprised of finite-size triangular lattices of gold bumps deposited on a gold thin film are studied by means of a near-field optical microscope. The plasmonic crystals fabricated by electron-beam lithography are illuminated by an incident surface plasmon polariton excited in the Kretschmann-Raether configuration at the gold/air thin-film interface for incident free-space wavelengths in the range $740--820\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$. Based on the measurement of the surface plasmon polariton (SPP) damping distance in the crystals, the existence of a band gap for an incident SPP traveling along the two symmetry axes $\ensuremath{\Gamma}M$ and $\ensuremath…
A large-energy-gap oxide topological insulator based on the superconductor BaBiO3
2013
Mixed-valent perovskite oxides based on BaBiO3 (BBO) are, like cuperates, well-known high-Tc superconductors. Recent ab inito calculations have assigned the high-Tc superconductivity to a correlation-enhanced electron--phonon coupling mechanism, stimulating the prediction and synthesis of new superconductor candidates among mixed-valent thallium perovskites. Existing superconductivity has meant that research has mainly focused on hole-doped compounds, leaving electron-doped compounds relatively unexplored. Here we demonstrate through ab inito calculations that BBO emerges as a topological insulator (TI) in the electron-doped region, where the spin-orbit coupling (SOC) effect is significant.…
Analytical methods to determine cocaine contamination of banknotes from around the world
2008
Abstract The presence of cocaine in a significant number of UK pounds (Xxxx), Euros (€) and North American banknotes ($) in general circulation requires appropriate tools to do determinations. This article discusses the-state-of-the-art in the analysis of cocaine on banknotes. We summarize the usual extraction methods of currency samples and compare them, especially with respect to avoiding sample damage. We critically discuss analytical methods, namely gas chromatography (GC) and liquid chromatography (LC), capillary electrophoresis (CE), immunoassay, thermal desorption tandem mass spectrometry (TD-MS2) and ion-mobility spectrometry (IMS). We also review cocaine levels on banknotes around …
Fundamentals and applications of stir bar sorptive dispersive microextraction: A tutorial review
2021
Current trends in sample preparation focus on the miniaturization of the process resulting in what is known as microextraction techniques. Among them stir bar sorptive dispersive microextraction (SBSDME) is one of the most recent techniques. It was presented a few years ago as a hybrid microextraction technique that combines the principles of stir bar sorptive extraction (SBSE) and dispersive solid phase extraction (DSPE). This novel technique introduces, into the sample solution, a bar-shaped magnet coated with a magnetic (nano)material, which is maintained on the surface by magnetism. Once stirring starts, the competitive action between magnetism and rotational force is exploited. At low …
Mucoadhesive Polymeric Films to Enhance Barbaloin Penetration Into Buccal Mucosa: a Novel Approach to Chemoprevention.
2018
Nowadays, chemoprevention by administering natural supplements is considered an attractive strategy to reverse, suppress, or prevent the evolution of premalignant oral lesions. In particular, Barbaloin exhibits anti-proliferative, anti-inflammatory, and anti-cancer properties, and it results useful in multi-therapy with classic chemotherapeutics. Therefore, in this work, mucoadhesive buccal films, as locoregional drug delivery system able to provide a targeted and efficient therapeutic delivery of Barbaloin, are proposed. Thus, Aloin extract-loaded Eudragit (R) RL100 or Eudragit (R) RS100-based buccal films were designed in order to obtain an easily self-administrable formulation capable of…
Numerical modelling of the tensile behaviour of BFRCM strips
2019
This paper aims at investigating the tensile behaviour of basalt fibres on cementitious matrix for the strengthening of masonry structures. The use of Basalt Fibre Reinforced Cementitious Matrix (BFRCM) is favourably considered by the scientific community because it represents a natural composite material with high compatibility with stone and masonry substrate. The study is developed through the generation of Finite Element (FE) models capable of reproducing the tensile behaviour of BFRCM strips with different number of layers of grid. For the scope, the micro-modelling approach is adopted assuming different levels of detail for the simulation of the interface constitutive behaviour. Fibre…
Asphalt mixtures modified with basalt fibres for surface courses
2018
Abstract This paper shows the results of an experimental study concerning the effect of introduction of basalt fibres in asphalt mixtures for surface course, mainly with regard to those to be used in urban areas, for dedicated bus lanes. Surface layers, where tire-pavement interactions occur, have to provide different properties such as high friction (very important for users’ safety), stability, resistance to meteorological agents, and contribution to the overall pavement performances. Considering that basalt fibres provide considerable physical and mechanical properties and above all high abrasion resistance, scope of the study is to evaluate the effects of these fibres on mixtures proper…
On thermal behaviour of DMC catalysts for ring opening polymerization of epoxides
2016
Abstract The thermoanalytical studies of two types of the double metal cyanide catalysts were carried out. The identity of the catalysts was characterized by an elemental analysis and FTIR. The thermoanalytical examinations performed with the use of TG-DSC, EGA-FTIR, EGA-MS shed new light on views of the bonding of the ligands in the DMC. The chemical justification of the processes responsible for the TG/DSC steps was proposed. Several organic ligand complexing states were found in both types of catalysts. The ligand-DMC bondings were decomposing stepwise in relatively low temperature ranges, which could suggest their negligible role at catalytic reaction being performed usually at higher t…
Acid-Base Properties of 2:1 Clays. I. Modeling the Role of Electrostatics
2010
We present a theoretical investigation of the titratable charge of clays with various structural charge (sigma(b)): pyrophyllite (sigma(b) = 0 e x nm(-2)), montmorillonite (sigma(b) = -0.7 e x nm(-2)) and illite (sigma(b) = -1.2 e x nm(-2)). The calculations were carried out using a Monte Carlo method in the Grand Canonical ensemble and in the framework of the primitive model. The clay particle was modeled as a perfect hexagonal platelet, with an "ideal" crystal structure. The only fitting parameters used are the intrinsic equilibrium constants (pK(0)) for the protonation/deprotonation reactions of the broken-bond sites on the lateral faces of the clay particles, silanol, =SiO(-) + H(+) --=…