Tuning the electronic properties of C12A7 via Sn doping and encapsulation

Cation doping in electride materials has been recently considered as a viable engineering strategy to enhance the electron concentration. Here we apply density functional theory-based energy minimisation techniques to investigate the thermodynamical stability and the electronic structures of Sn-doped and Sn-encapsulated in stoichiometric and electride forms of C12A7. The present calculations reveal that encapsulation is exoergic and doping is endoergic. The electride form is more energetically favourable than the stoichiometric form for both encapsulation and doping. Encapsulation in the electride results a significant electron transfer (1.52 |e|) from the cages consisting of extra-framework electrons to the Sn atom. The Sn forms almost + 4 state in the doped configuration in the stoichiometric form as reported for the electride form in the experiment. Similar charge state for the Sn is expected for the electride form though the extra-framework electrons localised on the Sn. Resultant complexes of both forms are magnetic. Whilst significant Fermi energy shift is noted for the doping in C12A7:O2− (by 1.60 eV) towards the conduction band, there is a very small shift (0.04 eV) is observed in C12A7:e−. Future experimental study on the encapsulation of Sn in both forms of C12A7 and doping of Sn in the stoichiometric form can use this information to interpret their experimental data.

Presence of phytochemicals in fruits and leaves of guava (Psidium guajava Linn.) for cancer prevention: A mini review

The present review deals with the bioactive compounds (phytochemicals) in the fruits and leaves of guava (Psidium guajava Linn.). In the present study, an attempt was done to survey of literatures for exact solvent extraction to know exact phytocompound and characterization by using instruments along with anticancer properties of these phytochemicals present in fruits and leaves of guava. The compilation of available literatures of last 10 years can be suitable ready references for future experimental study as in vitro and in vivo as well as new drug design as phytomedicines for cancer therapy. Keywords: Bioactive compounds, Psidium guajava, Guava fruits and leaves, Cancer therapy, Phytomedicines

General rogue wave solutions of the coupled Fokas–Lenells equations and non-recursive Darboux transformation

We formulate a non-recursive Darboux transformation technique to obtain the general n th-order rational rogue wave solutions to the coupled Fokas–Lenells system, which is an integrable extension of the noted Manakov system, by considering both the double-root and triple-root situations of the spectral characteristic equation. Based on the explicit fundamental and second-order rogue wave solutions, we demonstrate several interesting rogue wave dynamics, among which are coexisting rogue waves and anomalous Peregrine solitons. Our solutions are generalized to include the complete background-field parameters and therefore helpful for future experimental study.

SOME ISSUES OF EXPERIMENTAL STUDY OF CLAY VESSELS' FIRING PROCESS

This paper is dedicated to the study of clay vessels' firing treatment. It is one of the most important scientific tasks in the field of ancient ceramic investigations which is low provided by the reliable methods till now. The next questions are described here: first - the history of study of firing process under historical-and-cultural approach to the ancient pottery production; second - the organization and results of field experimental study of clay vessels' firing in fireplace and in oven made by the authors on the basis of Samara pottery experimental expedition (N.P. Salugina is a head of the expedition), third - the results of the laboratory research of firing temperature on experimental vessels by Bobrinsky's color method. We concentrate our attention on the study of firing vessels in oxidizing and reducing conditions, on analysis of oxidizing firing at the first step and special chemical-and-thermal treatment of vessels in reducing conditions by blacking at the second step. In the results of laboratory tests of vessels sherds' firing temperature we came to the conclusion that the method is need to improve. At the end of paper the authors put forward some kind of ways to decide the problem and a plan of future experimental study of pottery firing process.

Far-Infrared Radiation Modulators Using High-Tc Superconductors

The potential of using high-Tc superconductors as intensity modulators for far-infrared radiation is investigated in this work. Reflectance and transmittance for several design structures are computed using the published optical constants of the superconductor YBa2Cu3O7 and substrate materials. Notable differences in the reflectance and transmittance between the superconducting state and the normal state are illustrated. The best results are obtained based on the reflectance of thin films (10 nm–50 nm thick) on thin substrates (less than 100 μm thick) and for radiation incident on the substrate. This study demonstrates that high-Tc superconductive thin films can be used to build far-infrared radiation modulators. Future experimental study is recommended in order to materialize this promising thermo-optical device.

Theory of phase transitions in solid methanes. XIV. The total neutron scattering cross section in phase II of solid CH4

The total neutron cross section in phase II of solid CH4 is calculated as a function of the incident energy E0 and the temperature in the ranges [Formula: see text] and [Formula: see text]. The sample is assumed to be a polycrystal and the neutron beam to be unpolarized. The total cross section consists of two parts: proton spin-independent and dependent parts. The latter is given by a sum of σ0 and σ′. Both the spin-independent part and σ0 come from the elastic scattering and can together be cast in the form [Formula: see text] for both Oh andD2d molecules, where [Formula: see text] is the mean squared proton spin angular momentum within a single molecule. The quantity σ′ depends on the details of the spin–rotational states. The calculated total cross section can again be expressed approximately as a linear function of [Formula: see text] as was empirically found by Lushington and Morrison (Can. J. Phys. 55, 1580 (1977)). A prediction is offered for a possible future experimental study.