Polymer nanocomposites based on Cu(Cu
2
O)-LDPE with a volume fraction of 0.1–0.4 copper filler in the form of spherical nanoparticles with sizes from 10 to 25 nm were synthesized. The electrical ...conductivity of such composite nanomaterials was measured, which is 4.5–5 times higher than the electrical conductivity of a polyethylene matrix. To predict the electrical conductivity of such materials, an analysis of well-known mathematical models is carried out and models for predicting the electrical conductivity of such materials are selected that are adequate to the experimental data.
—Layered antireflection nanostructures based on SiO
2
/TiO
2
/SiO
2
have been developed for protective glasses of various optoelectronic devices. Optical transmission and reflection characteristics ...of metamaterials based on synthesized matrix nanocomposites Ag@PMMA are investigated. A new type of optically transparent electrically conductive nanomesh electrode (electrode based on porous anodic aluminum oxide) with a thin gold film has been developed.
CdS nanoparticles (NPs) as quantum dots (QDs) added into low density polyethylene (LDPE) can significantly change the MW dielectric properties of the composites. Introducing into the matrix of low ...density polyethylene CdS QDs increase the dielectric constant of more than twice. CdS QDs with concentration of 5 wt % to 20 wt % were prepared by the method of high-speed thermal decomposition. The size of CdS nanoparticles ranged from 2 nm to 7 nm. Experimental samples based on polymer-based nanocomposite in the form of thick films with a thickness of 80 to 100 microns were prepared by thermocompression. Complex dielectric permittivity of thick film samples was measured by T/R method from 2 to 8 GHz at room temperature (25°C). For samples with 20 wt % CdS NPs size effect was found. The change of dielectric properties of polymer composite materials is associated with the size of QDs. The dielectric constant and dielectric loss increases with decreasing size of the quantum dots. It is shown that the highest mean value of the dielectric constant and dielectric loss at a frequency range of 5 GHz to 8 GHz for cadmium sulfide nanoparticles with size of 4 nm were 12 and 189 dB/m, respectively. For QDs with ones of 6 nm average dielectric constant and dielectric loss were 5.8 and 134 dB/m, respectively. The effective dielectric constant and dielectric losses in the microwave range can be changed by CdS QDs of different sizes what consequently increases the possibility of using polymer nanocomposites as core elements of the microwave band-pass filters for various purposes.
The article presents the results of an experimental study of the thermo-optical properties of a polymer composite nanomaterial based on 10 wt % CdS-LDPE. It is shown that the temperature dependences ...of the refractive index have a hysteresis in the heating-cooling cycle. The thermo-optical coefficients of the material during its heating and cooling, which had a negative value from –0.00026 to –0.0076 1/K were estimated. In the temperature range of 55–75°C, a strong nonlinearity of the temperature dependences of the refractive index of the width and energy gap of the material was observed. With increasing temperature up to 65°C, a decrease in the width of the forbidden zone was observed, and at temperatures above 65°C an increase in the width of the energy gap was observed. The maximum change in the band gap was about 0.2 eV. A strong change in the band gap in the temperature range 55–75°C is associated with a phase transition in the material. The detected thermo-optical properties of the polymer composite nanomaterial can be useful in the development of nanophotonic information-processing devices.
The influence of the of the pore structure on the electron barrier height of Au–Al
2
O
3
structures is experimentally studied. The porous structures of anodic aluminum oxide of two types with through ...pores and pores in the form of a well are investigated. It is shown that, depending on the shape of the pore profile, the deposited thin gold film creates a different height of the electron barrier at the metal-insulator interface. The method of linear optical spectroscopy showed that the height of the barrier for structures with through pores is higher by 2.0 eV.
Spectral optical properties of synthesized ceramic nanoporous membranes based on anodic aluminum oxide coated silver in saturated ammonia gas flow have been experimentally investigated. Based on the ...measured transmission spectra and detected interference part of the spectra in wavelength range from 550 to 900 nm, temporal and spectral dependencies of the effective optical thickness and its changes in non-equilibrium conditions were obtained due to adsorption of ammonia molecules on silver film surface. According to detected and measured interference maximum shifts up to 14 nm in transmission spectra of Al
2
O
3
+ Ag membranes in ammonia gas flow, the possibility of constructing a selective interferometric optical sensors with 10–15 min response time is shown.
The influence of the soft electron flow and irradiating pulsed UV laser on dielectric states of polymer composite nanomaterial based on LDPE matrix is experimentally studied. It was shown that ...irradiation of the samples LDPE–ZnO by electron beam (10 keV) for 10–15 minutes gives rise the appearance of the horizontal portion of the temperature dependence of capacitance (permittivity) and to memory effect (slow relaxation of dielectric situation within a few days). Irradiation with pulsed UV laser of the LDPE–CdS sample allows you to switch into a conducting state and return it to their original state upon application of a weak electric field. The observed phenomena may find practical applications for the polymer electronic memories and switching devices.
In this work, results of modeling the intra-annual variability of water and ice circulation in the Arctic Ocean by means of the INMIO4.1 three-dimensional model of ocean dynamics and the CICE5.1 ...sea-ice model are considered. The coupled ocean–ice model is implemented on massively parallel computers under the control of the CMF2.0 cosimulation software package. Results of a numerical experiment carried out according to the CORE-I protocol are presented. Geographical distributions, mean values, and intra-annual variability of the model solution characteristics describing the flow of water through key straits at the boundaries of the Arctic Ocean, propagation paths and vertical structure of the warm Atlantic water layer, and the area and volume of sea ice are analyzed. Qualitative agreement with observational and other high-resolution modeling data is obtained.
We present the status of research and development of a new highly efficient liquid scintillator based on linear alkylbenzene and organosilicon scintillation fluor, so called NOL (Nanostructured ...Organosilicon Luminophore). The measurements of the emission kinetics under irradiation by gamma-quanta and alpha-particles were performed. The results of long term stability measurements are decribed.
The method of masking of a large-radius sphere made of an arbitrary material by a masking coating with a random quasi-zero refractive index is substantiated theoretically and experimentally. In this ...method of masking, the sphere is first coated with a mirror layer (e.g., high-reflectivity silver) and then with a masking layer with a thickness much smaller than the radius of the sphere. The fraction of the external radiation intensity bending around the sphere at the points of observation near the surface of the sphere and the extinction cross section of the sphere with the masking coating for points of observation far away from the sphere are calculated. It is shown that extinction cross section
Q
of the sphere with a masking coating is much smaller than 2
D
, where
D
is the geometrical cross section of the sphere; this corresponds to the masking effect for the sphere in the wavelength range of at least 450–1200 nm in the transparency region of the masking coating.
