Microwave Absorbing by Conducting Hybrid Nanocomposites Based on Magnetite Nanoparticles

Microwave absorbing properties of hybrid nanocomposites of Fe3O4 nanoparticles with carbon nanotubes and polyaniline (PANI) doped with dodecylbenzenesulfonic acid have been studied. It has been found that the the addition of nanostructured components increases the absorbtion of the nanocomposites. Moreover, CNTs affect the absorbtion in high frequency range, and Fe3O4 nanoparticles – in low frequency range. Introduction of conductive PANI into the matrix enhances the influence of nanomaterials on the absorbance of the films. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3491

Liquid and back gate coupling effect: towards biosensing with lowest detection limit

We employ noise spectroscopy and transconductance measurements to establish the optimal regimes of operation for our fabricated silicon nanowire field-effect transistors (Si NW FETs) sensors. A strong coupling between the liquid gate and back gate (the substrate) has been revealed and used for optimisation of signal-to-noise ratio in sub-threshold as well as above-threshold regimes. Increasing the sensitivity of Si NW FET sensors above the detection limit has been predicted and proven by direct experimental measurements.Comment: 18 pages, 6 figure

Modelling of servo-controlled pneumatic drives: a generalised approach to pneumatic modelling and applications in servo-drive design

The primary objective of this research is to develop a general modelling facility for modular pneumatic servo-drives. The component-oriented approach has been adopted as the modelling technique to provide the flexibility of modelling a wide variety of components and the segmentation of the non-linear system to less complex uncoupled component modules. A significant part of the research work has been devoted to identify a series of component modules of the single axis linear pneumatic servomechanism with standardised linking variables. The mathematical models have been implemented in a simulation software which produces time domain responses for design evaluation purposes. Alternative components for different servomechanism design were modelled as mutually exclusive modules which could be selected for assembly as if they were real physical entities. The philosophy of the approach was validated by tests on prototype servo-drives with matching components. Design analysis could be performed by simulating and comparing the performance of alternative system structures. [Continues.

Mechanical properties of biomorphous ceramics

Mechanical properties: The Vickers hardness and bending strength of porous biomorphic SiC (bioSiC) ceramics fabricated from different natural hardwoods were investigated. It has been found that these parameters are highly dependent on the geometrical densities of ceramics, and Vickers hardness values can be well described using the Ryskevitch-type equation. It has been shown that the data of geometrical density bio-SiC ceramics can be used to estimate mechanical parameters such as bending strength. Materials with advanced properties appropriate for surgical applications are being designed. Further ways to improve the mechanical properties of ceramics and ceramic products have been discusse

Ultrasensitive and highly specific detection of iodine ions using zirconium (IV)-enhanced oxidation

Nuclear energy has significantly promoted the development of human society. However, nuclear pollution caused by nuclear accidents can lead to significant hazards to the environment and human health. As a major radioactive product, radioactive iodine (mainly existing as I−) detection has attracted significant attentions. In this study, zirconium(IV) is used to enhance the oxidation of environmental I− to form I2. Subsequently, the generated I2 oxidizes the chemical chromogenic substrate 3,3′,5,5′-tetramethylbenzidine, which is used for I− detection and realizes an ultralow limit of detection (LoD) of 0.176 nM. The LoD of our method, to the best of our knowledge, is the lowest among those of the available chemical methods for I− detection. Furthermore, our detection method also shows high specificity and reliability, making it a promising technique for detecting I− in practical environments

Photothermal circular dichroism of single nanoparticles rejecting linear dichroism by dual modulation

Circular dichroism (CD) is the property of chiral nanoobjects to absorb circularly polarized light of either handedness to different extents. Photothermal microscopy enables the detection of CD signals with high sensitivity and provides a direct absorptive response of the samples under study. To achieve CD measurements at the single-particle level, one must reduce such artifacts as leakage of linear dichroism (LD) and residual intensity modulation. We have simulated our setup with a simple model, which allows us to tune modulation parameters to obtain a CD signal virtually free from artifacts. We demonstrate the sensitivity of our setup by measuring the very weak inherent CD signals of single gold nanospheres. We furthermore demonstrate that our method can be extended to obtain spectra of the full absorptive properties of single nanoparticles, including isotropic absorption, linear dichroism, and circular dichroism. We then investigate nominally achiral gold nanoparticles immersed in a chiral liquid. Carefully taking into account the intrinsic chirality of the particles and its change due to heat-induced reshaping, we find that the chiral liquid carvone surrounding the particle has no measurable effect on the particles' chirality, down to g-factors of 3 x 10(-4).Biological and Soft Matter Physic

Injection Spectroscopy of Deep Traps in Nanostructured Films of Cadmium Sulfide

Nanocrystallin CdS films with controlled stoichiometry deposited by CSVS were investigated by meth-od of the current-voltage characteristics in ITO/CdS /In structures. It was shown that in the case of cadmi-um excess (S Cd) charge flow mechanism is deter-mined by monomolecular recombination. In the band gap of CdS with excess of cadmium there was detect-ed localized states with energy Et = 0.514 ± 0.026 eV, while in the material with Excess sulfur there are two localized states with energy Et1 = 0.514 ± 0.026 eV and Et2 = 0.700 ± 0.026 eV. Full concentration of lo-calized states is more than 2·1021 m-3 – 5·1022 m-3. Dependence of injection in parameters and nature of in-jection in the structures based on nanostructured CdS films on their stoichiometry was determined When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3524