Concentration inhomogeneity in iron-carbon alloys is analyzed and controlled. It is shown that application of secondary-ion mass spectrometers with about 200 resolution with respect to the mass ...numbers and a comparatively large diameter of the primary ion beam (1 – 2 mm) gives results required for development and control of processes of structure formation in modified alloys and of changes in their physical and mechanical properties.
This paper is devoted to study of the formation of Gibbs floating layers from aqueous solutions of copper nanoparticles (Cu NPs) stabilized by the sodium dodecyl sulfate surfactant. Langmuir floating ...layers of arachidic acid formed on the surface of a water subphase containing Cu NPs were also studied. Adsorption of copper nanoparticles on a monolayer of arachidic acid at different conditions has been investigated. In the experiments the amount of copper nanoparticles in the subphase and the temperature of the subphase were changed. The performed analysis showed that the increase of subphase temperature from 29 to 42 °C leads to the increase of the area occupied by Langmuir floating layers in a liquid-condensed state by 30 and 32 %, respectively. After a single transfer of the floating layer onto the highly oriented pyrolytic graphite substrates, their surface microrelief was investigated by atomic force microscopy (AFM). The AFM scans showed that the obtained copper nanoparticles films contained separate areas with copper particles and their aggregates. With an increase of surface pressure from 10 to 40 mN/m, an increase of the height difference of the surface microrelief from 4 to 7 nm and an increase of the large aggregates number with lateral dimensions about 100 nm were observed.
Background and Objectives: Nanomedicine and drug delivery systems are a relatively new but rapidly developing branch of science, which investigate materials in the nano- and microscale range as ...diagnostic tools or carrier for delivery of therapeutic agents to specific targets within the body in a controlled manner. As far as the systemic administration faces a range of problems that cannot be solved by traditional approaches, it becomes extremely relevant to develop novel therapeutic options. Results: In this paper we provided information about the most interesting and promising strategies from our point of view that optimize the drug delivery process using various compositions of nano- and microcarriers of different nature and design, special physicochemical amplifiers, various devices, and methods. The current review briefly presents the latest advances in the field of nanomedicine and drug delivery systems driven by impressive recent results in the field of nanomaterials, drug carriers of different compositions, specific physicochemical amplifiers, various devices and methods. Few basic routes for drug delivery in vivo including injections, implantation and transdermal delivery open up a new avenue for an improved topical medical treatment which is considered and compared to each other in the current review. All of these routes offer certain advantages of terms drug absorption, targeting, prolongation, spatiotemporal accuracy, reduction of dosage and many others that must be taken into account to provide a correct approach for the treatment of a specific disease. Conclusion: Invasive and non-invasive implantation of drug delivery carriers and devices are reviewed together with transdermal routes leading to effective absorption of drugs with minimal side effects. The innovative approaches to drug delivery discussed here open venue for effective treatment of a wide range of diseases, especially chronic ones, that cannot be defeated by traditional approaches. Although transdermal delivery offers a promising non-invasive way to treat a variety of diseases, chronic illnesses can be treated more effectively by implantation of drug delivery devices with a bidirectional connection that in the future can drastically improve the quality of life. Diversity of emerging technologies in microelectronics, sensors and biomaterials leads to dramatic changes in the medical industry and appearance of new systems providing medical treatment in theranostics fashion.
Liquid crystal (LC) ligands have the ability to control the dispersion and the homogeneity of quantum dots (QDs) in solution. LC phase transition can be used as a tool to control the assembly of ...dispersed QDs. Comparing the results before and after the ligands exchange (oleic acid to liquid crystal) highlights some important differences in optical and morphology properties of QDs. We have studied changes in optical properties and a shift in the spectral wavelength band of QDs with LC ligands. Application of LC ligands leads to quenching of the emission and excitation spectra intensity of CdSe/CdS/ZnS QDs. Such hybrid materials have interesting potential for usage in a variety of applications such as photonic materials or (bio) chemical sensors.
Thin tin oxide films were fabricated by reactive RF magnetron sputtering. It was shown that the films possess gas sensitivity to ethanol vapor at 38°C. Measurements of the morphology and cleavage ...inner structure of the samples by atomic-force and scanning electron microscopy demonstrate that the films are composed of nanodimensional rod-like grains oriented normally to the substrate. The grains are separated by pores piercing the whole film. It was found that the grain diameter distribution is normal logarithmic one with several centers related as small integers, which indicates that the grains coalesce. The minimum grain size of 6 nm might correspond to the critical nucleus size under the used conditions of film deposition.
Hybrid structures consisting of an n-Si substrate covered with a cationic polyethylenimine layer and an anionic dye layer were fabricated. Their electrical properties were characterized using tunnel ...current measurements by a tungsten probe. The obtained I-V curves were analyzed using a modified diode equation. We found out that adsorption of the cationic polyelectrolyte decreases the barrier height of n-Si organic monolayer W structure, while adsorption of the low molecular weight anionic dye increases it. The results demonstrate that along with thermionic mechanism other ones are present which prevail at low voltage. In particular, electron tunneling dominates for a single monolayer on the silicon substrate, while, apparently, the Pool-Frenkel mechanism is typical for two monolayers.
We have studied the phase composition of thin polycrystalline tin oxide films deposited on silicon substrates by reactive RF magnetron sputtering. The films are sensitive to ethanol vapors at 38°C. ...They consist of SnO
2
crystallites with the average grain size of about 7 nm, covered with a nanodimensional layer of amorphous SnO phase. It was found that the volume fraction of the former phase is about 95% and that of the latter phase is about 5%. Calculations of the film texture indicate the predominant growth of SnO
2
crystals along 〈110〉, 〈211〉, and 〈310〉 crystal directions perpendicular to the substrate.
The paper presents an investigation of the antibacterial activity of composites that are obtained based on a natural sorbent with immobilized antibiotics, tetracycline, and doxycycline. Both the ...investigated composites effectively inhibited
Staphylococcus aureus
, but were not effective against
Escherichia coli
. The paper also presents the results of an investigation of the elemental composition and some characteristics of the porous surface of the glauconite sorbent of the Beloozero field in Saratov oblast.
The formation of CdSe quantum dots (QDs) monolayers was studied by Langmuir Blodgett method. The fluorescence (PL) spectra of QD monolayers were investigated at different substrate type (glass, ...silicon and ITO glass) and the influence of graphene sheets layer (as a conductive surface) on the QDs properties has also been studied. The optoelectronic properties of QDs can be tuned by deposition of insulating nano-size layers of the liquid crystal between QDs and conductive substrate. The monolayer of QDs transferred on conductive surface (glass with ITO) has lowest intensity of PL spectra due to quenching effect. The PL intensity of QDs could be tuned by using various type of substrates or/and by transformed high conductive layer. Also the photooxidation processes of CdSe QDs monolayer on the solid surface can be controlled by selection of suitable substrate. The current-voltage (I-V) characteristics of QDs thin film on ITO surface was studied using scanning tunneling microscope (STM).
Globular Graphite: Structure, Composition Anikin, A. A.; Venig, S. B.; Bilenko, D. I. ...
Metal science and heat treatment,
07/2014, Letnik:
56, Številka:
3-4
Journal Article
Recenzirano
The structure and elemental composition of graphite inclusions uncovered on high-strength cast iron by etching are studied. The chemical composition at various points and regions of graphite ...inclusions is determined. It is shown that the globular graphite is a unique lamellar-spiral system of micro- and nanoformations.
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