Investigation into the physical characteristics of the compounds XBiSe2 (X = Li, Na or K)

CONTEXT

As new materials, the ternary chalcogenides have recently brought scientists' attention. These materials are a novel class of semiconducting chemical compounds. They allow the increase of the photo-conversion efficiency, the performance, and the cheap energy cost. Such materials also provide a wide range of physical and chemical applications.

METHODS

The used investigation employs Density Functional Theory (DFT) implemented in the Wien2k package to systematically characterize the physical properties of ternary chalcogenide compounds XBiSe2 (X = Li, Na and K). Such method emphasizes their applicability to energy conversion technologies. Scrutinizing their electronic, optical, and thermoelectric properties elucidates the effect of alkali metal substitution on performance metrics. The results not only advance knowledge of these materials' physicochemical behaviors but also reveal their potential for tailored functionalization in next-generation energy and optoelectronic systems, marking a significant stride in material science and application-oriented research.

Electronic, magnetic, elastic, thermal and thermoelectric proprieties of Co2MnZ (Z=Al, Ge, Sn)

The full-potential linearized augmented plane-wave (FLAPW) method, which is based on density functional theory using the "WIEN2k" code. The exchange-correlation functional was taken within the generalized gradient approximation (GGA), has been used to study the structural, electronic, mechanical, magnetic, and thermal properties of Co₂MnZ (Z = Al, Ge, Sn) (CMZ) alloy. When using the GGA + U approximation, all compounds depict half-metallic behavior due to spin polarization at the Fermi level. Get the Curie temperature value and the magnetic moment. We find that the ferromagnetic state is more stable than the antiferromagnetic and nonmagnetic states. The effects of heat on lattice parameters, compressive modulus, volume, heat capacity and thermal expansion coefficient at several pressures were investigated. The thermoelectric performance of these systems was examined. Calculations are performed using the BoltzTrap code, that relies on the semiclassical Boltzmann transport equation. The Seebeck coefficient, electrical conductivity, thermal conductivity, and figure of merit are calculated taking into account the upper and lower spins.

The effect of dornase alfa on ventilation inhomogeneity in patients with cystic fibrosis

Outcome measures to assess therapeutic interventions in cystic fibrosis (CF) patients with mild lung disease are lacking. Our aim was to determine if the lung clearance index (LCI) can detect a treatment response to dornase alfa in paediatric CF patients with normal spirometry. CF patients between 6-18 yrs of age with FEV(1 )≥ 80% pred were eligible. In a crossover design, 17 patients received 4 weeks of dornase alfa and placebo in a randomised sequence separated by a 4-week washout period. The primary end-point was the change in LCI from dornase alfa versus placebo. A mixed model approach incorporating period-dependent baselines was used. The mean ± sd age was 10.32 ± 3.35 yrs. Dornase alfa improved LCI versus placebo (0.90 ± 1.44; p = 0.022). Forced expiratory flow at 25-75% expired volume measured by % pred and z-scores also improved in subjects on dornase alfa (6.1% ± 10.34%; p = 0.03 and 0.28 ± 0.46 z-score; p = 0.03). Dornase alfa significantly improved LCI. Therefore the LCI may be a suitable tool to assess early intervention strategies in this patient population.