Search results for " engineering"
showing 10 items of 38291 documents
Computer Simulations of the Band Structure and Density of States of the Linear Chains of NaCl Ions
2019
The authors thank Eugene Kotomin and V. Kuzovkov for fruitful discussions and valuable suggestions. A.I.P thanks A.Moskina for the technical assistance in preparation of the manuscript. A.I.P also gratefully acknowledges a project LZP-2018/1-0214 from the Latvian Council of Science for partial support.
Review: Electrostatically actuated nanobeam-based nanoelectromechanical switches – materials solutions and operational conditions
2018
This review summarizes relevant research in the field of electrostatically actuated nanobeam-based nanoelectromechanical (NEM) switches. The main switch architectures and structural elements are briefly described and compared. Investigation methods that allow for exploring coupled electromechanical interactions as well as studies of mechanically or electrically induced effects are covered. An examination of the complex nanocontact behaviour during various stages of the switching cycle is provided. The choice of the switching element and the electrode is addressed from the materials perspective, detailing the benefits and drawbacks for each. An overview of experimentally demonstrated NEM swi…
Supramolecular Modification of ABC Triblock Terpolymers in Confinement Assembly
2018
The self-assembly of AB diblock copolymers in three-dimensional (3D) soft confinement of nanoemulsions has recently become an attractive bottom up route to prepare colloids with controlled inner morphologies. In that regard, ABC triblock terpolymers show a more complex morphological behavior and could thus give access to extensive libraries of multicompartment microparticles. However, knowledge about their self-assembly in confinement is very limited thus far. Here, we investigated the confinement assembly of polystyrene-block-poly(4-vinylpyridine)-block-poly(tert-butyl methacrylate) (PS-b-P4VP-b-PT or SVT) triblock terpolymers in nanoemulsion droplets. Depending on the block weight fractio…
Elongation and plasmonic activity of embedded metal nanoparticles following heavy ion irradiation
2023
Shape modification of embedded nanoparticles by swift heavy ion (SHI) irradiation is an effective way to produce nanostructures with controlled size, shape, and orientation. In this study, randomly oriented gold nanorods embedded in SiO2 are shown to re-orient along the ion beam direction. The degree of orientation depends on the irradiation conditions and the nanorod's initial size. SHI irradiation was also applied to modify spherical metallic nanoparticles embedded in Al2O3. The results showed that they elongate due to the irradiation comparably to those embedded in SiO2. Metallic nanostructures embedded in dielectric matrices can exhibit localized surface plasmon (LSP) modes. The elongat…
Second Harmonic Emission From Dielectric Nanoresonators in the Absorption Regime
2023
We study second harmonic generation in dielectric nanocylinders as a function of the wavelength of the incident field and geometrical dimensions. Uncommonly, we consider a spectral range in which the emitted nonlinear signal is partially absorbed by the dielectric. Surprisingly, we reveal that the second harmonic efficiency does not decrease as the imaginary part of the complex dielectric refractive index increases. Indeed, the presence of higher order multipoles supported by the resonators at the fundamental wavelength can significantly boost the generated second harmonic signal even in the dielectric absorption spectral region achieving nonlinear efficiency of the same order of magnitude …
Surface modification of poly(ethylene-co-acrylic acid) with amino-functionalized silica nanoparticles
2011
In this work we studied the possibility to achieve a hybrid-surface through the modification, via a facile wet chemical process, of the surface of films of poly(ethylene-co-acrylic acid) (EAA) with amino-modified silica nanoparticles. Films of EAA were preliminarily activated by the introduction of -COCl groups on their surface. Silica nanoparticles were thereafter covalently bound on the polymeric surface as confirmed by FTIR, ATR-FTIR, XPS, NMR and SEM determinations. The nanoparticles formed a multilayer on the film surface and covered almost uniformly the whole film surface. Direct measurements of superficial amino groups by titration allowed us to detect a concentration of about 18 nmo…
Biocompatible Lipid Nanoparticles as Carriers to Improve Curcumin Efficacy in Ovarian Cancer Treatment
2017
Curcumin is a natural molecule with proved anticancer efficacy on several human cancer cell lines. However, its clinical application has been limited due to its poor bioavailability. Nanocarrier-based drug delivery approaches could make curcumin dispersible in aqueous media, thus overtaking the limits of its low solubility. The aim of this study was to increase the bioavailability and the antitumoral activity of curcumin, by entrapping it into nanostructured lipid carriers (NLCs). For this purpose here we describe the preparation and characterization of three kinds of curcumin-loaded NLCs. The nanosystems allowed the achievement of a controlled release of curcumin, the amounts of curcumin r…
Experimental Procedures of Accelerated Aging and Evaluation of Effectiveness of Nanostructured Products for the Protection of Volterra (Italy) Panchi…
2022
The aims of the research were to evaluate the effectiveness of the application of nanostructured products on Volterra calcarenite stone and to define the experimental conditions and procedures of accelerated aging tests, able to simulate different degradation on the studied lithotype. The work focused on methods of performing accelerated aging tests in order to simulate different effects of environmental decay involving stone used on a historical site. The rock samples were examined before and after three treatment types: cyclic salt spray chamber, cycles of freezing–thawing and cycles of thermal shock. After each artificial aging cycle, changes in appearance were noted and chemical and phy…
A non-enzymatic electrochemical hydrogen peroxide sensor based on copper oxide nanostructures
2022
This work was supported by ERDF project No. 1.1.1.2/16/I/ 001, research application number 1.1.1.2/VIAA/4/20/743 "Development of nanomaterial-based electrochemical sensor for detection of hydrogen peroxide". Institute of Solid State Physics, University of Latvia as the Center of Excellence has received fund ing from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017 TeamingPhase2 under grant agree ment No. 739508, project CAMART2.
Progettare nel caleidoscopio del piccolo.La rivoluzione tecnica della multidisciplinare "nanoscala".
2018
Si può generalmente affermare che l’industria delle costruzioni costituisca un settore capace di attivare grandi attività economiche e di sperimentazione, anche se spesso esso utilizzi componenti e sistemi abbastanza obsoleti, se paragonati ad altri settori industriali quali, ad esempio, quello bellico o farmaceutico. La ricerca applicata e lo sviluppo di nuovi materiali innovativi, dalle prestazioni elevate, economicamente convenienti e sostenibili, appaiono una delle priorità delle agende scientifiche di parecchie Nazioni, con investimenti - sia nel pubblico che nel privato - di diversi milioni di dollari l’anno. La scelta di nuovi materiali dalle caratteristiche avanzate è, al giorno d’o…