Alpha decay chains study for the recently observed superheavy element Z=117 within the Isospin Cluster Model

The recently observed $\alpha$-decay chains $^{293-294}117$ were produced by the fusion reactions with target $^{249}Bk$ and projectile $^{48}Ca$ at Dubna in Russia. The reported cross-sections for the mentioned reaction are $\sigma=0.5(+1.1,-0.4)$pb and $\sigma$=1.3(+1.5,-0.6)$pb$ at $E^{*}=35MeV$ and $E^{*}=39MeV$, respectively. The Q-values of $\alpha$-decay and the half-lives $Log_{10}T^{\alpha}_{1/2}$(s) are calculated for the $\alpha$-decay chains of $^{293-294}117$ nuclei, within the framework of Isospin Cluster Model (ICM). In the ICM model the proximity energy is improved by using the isospin dependent radius of parent, daughter and alpha particle. The binding energy $B(A_{i}, Z_{i})$ (i=1,2) of any nucleus of mass number A and atomic number Z was obtained from a phenomenological and more genaralized BW formula given by \cite{samanta02}. The calculated results in ICM are compared with the experimental results and other theoretical Macro-Microscopic(M-M), RMF(with NL3 and SFU Gold forces parameter) model calculations. The estimated values of $\alpha$-decay half-lives are in good agreement with the recent data. The ICM calculation is in favor of the persence of magic number at N=172

Thermal expansion and polarization of (1-x)PNNxPT solid solutions

The paper presents the results of detailed studies of the thermal expansion of (1-x)PbNi1/3Nb2/3O3-xPbTiO3 solid solutions with x¼0- 0.8. The anomalous and lattice contributions to deformation and the thermal expansion coefficient are analyzed and the mean square polarization Pd is determined. The results obtained are discussed within the framework of the thermodynamic theory and the Landau 2-4-6 coefficients for solid solutions are estimate

Investigation of the thermal expansion and heat capacity of the CaCu3Ti4O12 ceramics

The thermal expansion of the CaCu3Ti4O12 ceramics has been measured over a wide temperature range 120–1200 K. The high quality of the samples under study has been confirmed by good agreement of the results of measurements of the heat capacity in the range 2–300 K and in the vicinity of the phase transition of magnetic nature at 25 K with the data for the single crystal. No anomalies in the thermal expansion that can be associated with the phase transition at 726–732 K assumed by other investigators have been found. The influence exerted on the thermal expansion by the heat treatment of the sample in a helium atmosphere and in air has been investigated

Thermal expansion and polarization of (1-x)PNN-xPT solid solutions

The paper presents the results of detailed studies of the thermal expansion of (1-x)PbNi1/3Nb2/3O3-xPbTiO3 solid solutions with x = 0-0.8. The anomalous and lattice contributions to deformation and the thermal expansion coefficient are analyzed and the mean square polarization Pd is determined. The results obtained are discussed within the framework of the thermodynamic theory and the Landau 2-4-6 coefficients for solid solutions are estimated

Perovskite-like fluorides and oxyfluorides : phase transitions and caloric effects

An analysis of the effect that chemical and hydrostatic pressures have on the thermodynamic properties of perovskite like fluorine–oxygen compounds A2A'MeOxF6–x has revealed that materials under going order–disorder transitions and having significant external pressure compliance have the highest caloric efficiency. Some of the fluorides and oxyfluorides under study can be considered promising solid coolants

Structural, thermal and optical properties of elpasolite-like (NH4)2KZrF7

New fluoride compound (NH4)2KZrF7 with the elpasolite structure (sp. gr. Fm-3m) was synthesized by partial cationic substitution in (NH4)3ZrF7 cryolite. Due to small difference in ionic radii of K+ and NH+ , non-equivalent crystallographic positions 8c and 4b are occupied by both cations. Investigations of thermal, optical and structural properties in a wide range of temperature revealed two phase transitions Fm-3m ↔ P42/ncm ↔ P42/nmc of the first order. The results obtained are discussed in comparison with the data for the previously studied related cryolite (NH4)3ZrF

Heat capacity, thermal expansion and barocaloric effect in fluoride K2TaF7

The heat capacity and thermal expansion of potassium heptafluorotantalate were studied. The room temperature phase P21=c is stable at least to 4 K. The strong first-order phase transition P21=c Pnma at T0 ¼ 486:2K is accompanied by giant changes in the entropy, DS0 ¼ 22:3 J ðmolKÞ 1; and volume strain, dV0=V ¼ 3:6%. A rather high sensitivity of K2TaF7 to pressure was found, dT0=dp ¼ 220KGPa 1. Significant extensive and intensive barocaloric effects are found at low pressure. The possibility of improving the barocaloric properties is discussed