All-dielectric nanoantenna for efficient reflectors irradiation

In this paper, we propose a new kind of nanoantenna for effective illumination of parabolic surfaces, constituting of a silicon cylinder acting as a reflector and dipole source as an emitter. Tailored parameters of the nanoantenna ensure specific radiation pattern with broad main lobe and strongly suppressed side lobes that in the E-plane of the dipole is quite similar to the ideal “П” configuration, necessary for an as uniform as possible illumination of parabolic surfaces. This above radiation pattern is mostly due to the properly designed dielectric inclusion in the reflector that, therefore, is free of any losses. Consequently, we study how varying the antenna parameters affects the radiation pattern.Results of our numerical simulations are compared with already existing ones and highlight the principal features that provide the desired effect. Furthermore, due to the simple geometry of the inclusions, the considered nanoantenna, required in application such as nanoreflector antennas and/or nanophotonic devices, exhibits advantages in manufacturing processes with respect to already proposed solutions

Usage of Layer-by-Layer Method for Obtaining Polyelectrolyte Multilayer Films Containing Transition Metal Cations

The alternating layer-by-layer deposition of oppositely charged polyelectrolytes at solid substrates is an attractive technique for preparation of nanostructured surface coatings of controlled thickness. This paper reports the results of covalently binding of cobalt (II) and copper (II) ions within polyelectrolyte multilayers (PEMs). We have used polycation as polyethyleneimine (BPEI) and polyanion as poly(acrylic acid) (PAA) and the electrostatic layer-by-layer assembly technique to make uniform thin film coating on solid template with controllable thickness. Thermodynamic characteristics as stability constant, free Gibbs energy, enthalpy and entropy of complex forming processes of these polyelectrolytes with Co(II) and Cu(II) cations in solution were calculated by modified method of Bjerrum. The correlation between log ОІ values and some of the fundamental properties of the metal ions are discussed. It was found that the ratio of Me:L in water solvent is 1:4 in the investigating systems Cu2+:BPEI and Co2+:BPEI and in the systems CРѕ2+:PAA and CРѕ2+:PAA - 1:2. PEMs were deposited onto silicon wafers, glass slides, or coated on silica oxide particles. Dipping solutions of different pH were used in order to find the optimum conditions for absorbing maximum amount of metal cations. These PEMs films are found to offer high capacity and selectivity for copper over cobalt in both acidic and alkaline media. Preliminary investigation have shown that metal containing PEMs has catalytic activity for oxidation of toluene with molecular in mild condition. The alternating layer-by-layer deposition of oppositely charged polyelectrolytes at solid substrates is an attractive technique for preparation of nanostructured surface coatings of controlled thickness. This paper reports the results of covalently binding of cobalt (II) and copper (II) ions within polyelectrolyte multilayers (PEMs). We have used polycation as polyethyleneimine (BPEI) and polyanion as poly(acrylic acid) (PAA) and the electrostatic layer-by-layer assembly technique to make uniform thin film coating on solid template with controllable thickness. Thermodynamic characteristics as stability constant, free Gibbs energy, enthalpy and entropy of complex forming processes of these polyelectrolytes with Co(II) and Cu(II) cations in solution were calculated by modified method of Bjerrum. The correlation between log ОІ values and some of the fundamental properties of the metal ions are discussed. It was found that the ratio of Me:L in water solvent is 1:4 in the investigating systems Cu2+:BPEI and Co2+:BPEI and in the systems CРѕ2+:PAA and CРѕ2+ :PAA - 1:2. PEMs were deposited onto silicon wafers, glass slides, or coated on silica oxide particles. Dipping solutions of different pH were used in order to find the optimum conditions for absorbing maximum amount of metal cations. These PEMs films are found to offer high capacity and selectivity for copper over cobalt in both acidic and alkaline media. Preliminary investigation have shown that metal containing PEMs has catalytic activity for oxidation of toluene with molecular in mild condition

Ideal Magnetic Dipole: Scattering and Mantle Cloaking Effects

Artificial magnetic response is one of the recent research topics that is receiving significant attention. Nevertheless, because of the difficulties in exciting not only the magnetic moment but also multipoles of different order, and the presence of losses, the efficiency of its generation is strongly compromised. On the other hand, the presence of a cloaking phenomena can be described in terms of anapole mode, which consists in the compensation of the scattering due to the moment of the electric dipole with the toroidal one. Because of this effect, the remaining part of the field will exhibit a strong(er) magnetic dipole moment response. In the present study, the response of a cloaking device based on a real-life geometry is therefore analysed with particular focus the anapole mode excitation and ideal magnetic dipole behaviour

Investigation of behaviour of sand-fines mixtures using direct shear (DS) testing and dem simulations

The Critical State Framework describes a relationship between the shear strength and the void ratio of a soil and it is mostly applicable to describe the behavior of pure clay and pure sand samples of relatively uniform particle sizes. However, mixtures of different particle size materials do not always follow this theory; the presence of some small particles can destabilize and affect the behavior of those mixtures under the applied shear stress. This Project's main objective is to investigate the effect of the fines content in mixtures of sand and fine particles using Discrete Element Method (DEM) computer simulations and Direct Shear (DS) laboratory testing. Investigation of the effect of the fines content on the force distribution between particles and hence on the shear strength of the materials can be helpful in the prediction of the shear strength and deformation characteristics of granular mixtures in civil engineering and powder industries

The Peculiarities of Interactions in the System Containing Polyethyleneimine and Unithiol

Interaction processes of polyethyleneimine (PEI) with unithiol were investigated by potentiometric, conductometric and viscosimetric methods. It was stated that in the PEI-unithiol system a complex acidbasic interaction resulted in the formation of salt complex of 2:1 composition. On the basis of experimental data it was stated that complex PEI-unithiol is perspective as a polyadsorbent for many metal ions

State of preparation of a teacher-psychologist for professional adaptation to an inclusive educational environment: Eurasian aspects

The article considers the conditions for preparing a teacher-psychologist for professional adaptation in the environment of inclusive education in the post-Soviet space. The authors consider the work on inclusive education and psychological and pedagogical support for problem categories of the population based on concepts in the field of education. The article is an analytical review. We analyse scientific and pedagogical research on the problems of domestic and foreign inclusive education, the process of personal development and career guidance in the countries of Eurasia, primarily Russia and Kazakhstan. Professional training of future specialists consists in the formation at a high level of professionally important qualities of their morality, communication skills, will, intelligence, etc. We consider the state of inclusive education in higher educational institutions of Russia and Kazakhstan, we focus on the issue of preparing a teacher-psychologist for professional adaptation in an inclusive education environment. The authors present in the article the results of research conducted by students on the issues of professional adaptation at the University