Polystyrene-based nanocomposites with different fillers: fabrication and mechanical properties

The paper presents a comprehensive analysis of elastic properties of polystyrene-based nanocomposites filled with different types of inclusions: small spherical particles (SiO2 and Al2O3), alumosilicates (montmorillonite, halloysite natural tubules and Mica) and carbon nanofillers (carbon black and multi-walled carbon nanotubes). Composites were fabricated by melt technology. The analysis of composite melts showed that the introduction of Montmorillonite, Multi-walled carbon nanotubes, and Al2O3 particles provided an increase in melt viscosity by an average of 2 to 5 orders of magnitude over the pure polystyrene. Block samples of composites with different filler concentrations were prepared, and their linear and nonlinear elastic properties were studied. The introduction of more rigid particles led to a more profound increase in the elastic modulus of the composite, with the highest rise of about 80% obtained with carbon fillers. Carbon black particles provided also an enhanced strength at break of about 20% higher than that of pure polystyrene. The nonlinear elastic moduli of composites were shown to be more sensitive to addition of filler particles to the polymer matrix than the linear ones. The nonlinearity coefficient $\beta$ comprising the combination of linear and nonlinear elastic moduli of a material demonstrated considerable changes correlating with changes of the Young's modulus. The absolute value of $\beta$ showed rise in 1.5-1.6 times in the CB- and HNT-containing composites as compared to that of pure PS. The changes in nonlinear elasticity of fabricated composites were compared with measurements of the parameters of bulk nonlinear strain waves in them. Variations of wave velocity and decay decrement correlated with observed enhancement of materials nonlinearity

Controlled light-matter coupling for a single quantum dot embedded in a pillar microcavity using far-field optical lithography

Using far field optical lithography, a single quantum dot is positioned within a pillar microcavity with a 50 nm accuracy. The lithography is performed in-situ at 10 K while measuring the quantum dot emission. Deterministic spectral and spatial matching of the cavity-dot system is achieved in a single step process and evidenced by the observation of strong Purcell effect. Deterministic coupling of two quantum dots to the same optical mode is achieved, a milestone for quantum computing.Comment: Modified version: new title, additional experimental data in figure

An empirical approach to studying gender attitude to parenting

Background. The paper provides the results of studying gender views on parenthood. For efficient performance of the parent role the system of the subject’s ideas about the phenomenon of “parenthood” and its specific features, as well as personal features aimed at the effective performance of parental functions by both women (mothers) and men (fathers) are laid emphasis on. The Objective is to describe the pilot experimental research focused on males and females’ attitude to parenthood. The hypothesis of the study is an assumption about gender-specific attitude to parenthood in males and females in relation to the parental roles and functions that are eventually actualized in children. Females are focused on personal relationships with a child and emotionally coloured attitudes towards them, while for males mostly active forms of parenting are typical. Design. The first stage of theoretical understanding of the issue included the literature review of the foreign and Russian national psychologists focused on the psychology of parenthood (A. Adler, E. Badinter, D. Winnicott, M. Marcons, M. Mead, D. Peynes, S. Fanti, E. Erickson; T.V. Andreeva, K.N. Belogay, N.N. Vasyagina, A.I. Zakharova, O.A. Karabanova, S.Yu. Meshcheryakova, R.V. Ovcharova, V.A. Ramikh, Yu.A. Tokareva, G.G. Filippova, L.B. Schneider, etc.). The second stage of the research was focused on the study of gender-specific ideas about parenthood. Results. Based on the analysis of the existing approaches to understanding the phenomenon of “parenthood”, we defined it as a complex personal education including positive affective manifestations of the subject in relation to children shaped in the process of his interaction with the child and having a positive impact on the entire harmonious development and education of children. The survey data showed that the respondents expressed gender-specific attitudes to parenthood. In particular, the discrepancy lies in the perceptions of males and females of the “ideal parent” and their parental roles. Conclusion. The study proved the presence of gender features in the ideas of parenthood. To optimize the level and content of ideas about parenting will contribute to further rendering psychological support for the family

The influence of the microstructure morphology of two phase Ti-6Al-4V alloy on the mechanical properties of diffusion bonded joints

The influence of ultra fine grained (UFG) and coarse grained (CG) microstructure of the titanium alloy Ti-6Al-4V on the strength of a diffusion bonded (DB) joint was studied using a laboratory DB fixture and a new shear test rig. The DB process was carried out at 725°C and 825°C during 2 and 4 hours in a vacuum furnace. Coarsening of grain structure resulting from different DB cycles was quantified. The chain pores were observed at 725°C for both microstructure conditions bonded during 2 hours. The increase of bonding time up to 4 hours leads to subsequent elimination of the pores. The UFG samples bonded at 725°C showed a higher level of the shear strength than CG samples for both bonding times. The CG material demonstrated the highest shear strength after 4 hours of DB bonding at 825°C. The increase of the creep deformation of UFG samples when compared to the CG condition was observed as a result of DB at of 725° C during 4 hours