We present and discuss the results of calculations of the CaF2 bulk and surface electronic structure. These are based on the ab initio Hartree–Fock (HF) method with electron correlation corrections and on Density Functional Theory (DFT) calculations with different exchange-correlation functionals, including hybrid exchange techniques. Both approaches use the localised Gaussian-type basis set. A...

The aims of this study were (1) to assess the amount of fluoride (F) released from varnishes containing calcium glycerophosphate (CaGP) and (2) to assess the effect of the experimental varnishes on in vitro demineralization. Six test groups using 5 varnishes: base varnish (no active ingredients); Duraphat® (2.26% NaF); Duofluorid® (5.63% NaF/CaF2); experimental varnish 1 (1% CaGP/5.63% NaF/CaF2...

Nickel is an important strategic metal in the world. As sulfide ore containing high-grade nickel increasingly depleted, laterite ore, which rich resources, has attracted people’s attention. In this paper, reduction roasting-magnetic separation process used to study method of preparing ferronickel concentrates from low-grade under action composite additives (Na2CO3 and CaF2). The research result...

Light-emitting diodes based on quantum dots as an active emission can be considered a promising next generation for application in displays and lighting. We report theoretical investigation of green at 550 nm microcavity inorganic–organic light-emitting devices Zn (Te, Se) alloy layer. Distributed Bragg Reflector (DBR) has been applied bottom mirror. The realization high-quality DBR consisting ...

mold powders used in the continuous casting of steel contain the harmful caf2 as a main substance developing toxic gases such as sif4 and hf at elevated temperatures. in this study, three samples of i1, i2 and i3, which contained gypsum free portland cement clinker with different percentages of fe2o3 (5.68, 6.83, 8.02 ) and f- (2.09, 1.06, 0), were prepared and their main characteristics were c...

An all-transparent symmetric trilayer structure, which consists of a high-index center layer coated on both sides by a low-index film and embedded in a high-index prism, can function as an efficient polarizer or polarizing beam splitter under conditions of frustrated total internal reflection over a wide range of incidence angles. For a given set of refractive indices, all possible solutions fo...

Calcium fluoride is a slightly soluble compound commonly extracted from ores via flotation at elevated pH, where surfactant molecules bind with hydroxylated surface sites. The addition of F-(aq) suppresses surfactant adsorption by replacing these sites. In this paper, we look at the effects of aqueous Cl-, Br-, F-, and SO4(2-) on the water structure at the CaF2/H2O interface at a pH where surfa...