Investigation of some new results of entropy for titanium difluoride

High Entropy Oxides: Structure and Properties

MnCo1.5Fe0.5O4 spinel oxide was synthesized using the sol-gel technique, followed by heat treatment at various temperatures (400, 600, 800, and 1000 °C). The prepared materials were examined as anode electrocatalysts for water-splitting systems in alkaline environments. Solid-state characterization methods, such as powder X-ray diffraction and X-ray absorption spectroscopy (XAS), were used to analyze the materials' crystallographic structure and surface characteristics. The intrinsic activity of the MnCo1.5Fe0.5O4 was fine-tuned by altering the electronic structure by controlling the calcination temperature, and the highest activity was observed for the sample treated at 800 °C. A shift in the valence state of surface cations under oxidative conditions in an alkaline solution during the oxygen evolution reaction was detected through ex situ XAS measurements. Moreover, the influence of the experimental conditions on the electrocatalytic performance of the material, including the pH of the electrolyte and the temperature, was demonstrated.

This paper develops a sputtering-induced surface roughness model. The model is necessary to control surface roughness of a replicating tool that is machined by focused ion beam (FIB). The significant Gaussian intensity level of FIB profile is determined first, the mathematical model of surface roughness is then developed. The surface roughness function is the combination of the beam function and the material function. The beam function includes ion type, acceleration energy, ion flux, ion beam intensity distribution, tailing and neighboring of the successive beams, and dwell time. The cumulative intensity at a location is calculated by the algebraic summation of individual beam intensity delivered to every pixel successively. The material function includes the inherent material properties related to the ion beam micromachining, such as crystallographic structure and orientation, atomic density, binding energy. Experimental data for silicon verifies the validity of this model.

Impact of the vulcanization process on the structural characteristics and IgE recognition of two allergens, Hev b 2 and Hev b 6.02, extracted from latex surgical gloves

Lithium titanates are used in various applications, such as anode materials for lithium intercalation (Li4Ti5O12) or breeding materials in fusion reactors (Li2TiO3). Here, we report the formation of nano-crystalline lithium titanates by a mechanochemical approach and present a deeper insight into their structural characteristics by X-ray diffraction (XRD) and solid-state NMR spectroscopy. The compounds were synthesized in a high-energy planetary ball mill with varying milling parameters and different grinding tools. NaCl type Li2TiO3 (α-Li2TiO3) was formed by dry milling of lithium hydroxide with titania (rutile or anatase) and by a milling induced structure transformation of monoclinic β-Li2TiO3 or spinel type Li4Ti5O12. Heating of mechanochemical prepared α-Li2TiO3 induces a phase transformation to the monoclinic phase similar to hydrothermal reaction products, but a higher thermal stability was observed for the mechanochemical formed product. Microstructure and crystallographic structure were characterized by XRD via Rietveld analysis. Detailed phase analysis shows the formation of the cubic phase from the various educts. A set of two lattice parameters for α-Li2TiO3 was refined, depending on the presence of OH− during the milling process. An average crystallite size of less than 15 nm was observed for the mechanochemical generated products. The local Li environment detected by 6Li NMR revealed Li defects in the form of tetrahedral instead of octahedral site occupation. Subsequent adjustment of the structural model for Rietveld refinement leads to better fits, supporting this interpretation.

Ni-Mn-based Heusler alloys are known to demonstrate magnetic shape memory and giant magnetocaloric effect (MCE). These effects depend on the phases, crystallographic and magnetic phase transitions, and the crystallographic texture characteristics. These structural characteristics, in turn, are a function of the processing parameters. In the current work, Ni55.5Mn18.8Ga24Si1.7 Heusler alloy was processed by melt-spinning under a helium atmosphere. This process results in a fine microstructure. The ribbon that was produced with a narrower nozzle width, faster wheel speed, and higher cast temperature, indicating a faster cooling rate, had double the magnetic entropy change close to room temperature. However, the other ribbon demonstrated a large entropy change over a broader temperature range, extending its usability. The effect of the melt-spinning process parameters on the developing microstructure, crystallographic structure and texture, transformation temperatures, and the magnetic entropy change were studied to explain the difference in magnetocaloric behavior.

The role of Co substitution in the structural characteristics and magnetic properties of La2CoxNi1-xMnO6 epitaxial film

In terms of density functional theory in combination with a statistical thermodynamic method, we have investigated the Sc2C76 species including dimetallofullerenes Sc2@C76 and carbide clusterfullerenes Sc2C2@C74. Two dimetallofullerenes, Sc2@Cs(17490)-C76 and Sc2@Td(19151)-C76, possess the lowest relative energies but exhibit poor thermodynamic stability within the fullerene-formation region (500-3000 K). In contrast, four carbide clusterfullerene isomers, Sc2C2@D3h(14246)-C74, Sc2C2@C2v(14239)-C74, Sc2C2@C2(13333)-C74, and Sc2C2@C1(13334)-C74, have excellent thermodynamic stability when considering the temperature effect. The Sc2C2@D3h(14246)-C74 isomer, which satisfies the isolated-pentagon rule (IPR), was characterized by its crystallographic structure; however, the other three non-IPR structures with two pairs of pentagon adjacencies are predicted for the first time. In particular, Sc2C2@C2(13333)-C74 and Sc2C2@C1(13334)-C74 are linked by a single Stone-Wales transformation. Meanwhile, bonding critical points and Mayer bond orders in the four isomers were analyzed to disclose the unique interactions between the inner clusters and cages. Additionally, the structural characteristics, 13C and 45Sc NMR chemical shifts, and IR spectra of the four stable isomers are introduced to assist experimental identification and characterization in the future.

Structural features and dynamic investigations of the membrane-bound cytochrome P450 17A1

Several affordable and pollution-free technologies have drawn a lot of attention because of the pressure of our energy needs and environmental problems; among these, thermoelectric technology has made enormous advances. It has been known that thermoelectric materials are efficient in transforming waste heat energy into electricity. The efficiency of thermoelectric materials is typically assessed using the ZT value, ZT = S2T/ρκ. Several methods have been highlighted in the literature for improving thermoelectric figure of merit. This review stands out for its particular emphasis on cutting-edge techniques that are leading to a new era of thermoelectric innovation, including doping, co-doping, alloying, nanostructuring, and nanocompositing. Our focus is on mid-temperature range thermoelectric materials, which operate between 500 and 900 K and have enormous potential for high-efficiency thermoelectricity and waste heat recovery due to their inherent thermal and electrical properties. This review provides a foundational understanding of thermoelectric concepts as well as obstacles to improving the figure of merit and the various classes of mid-temperature range thermoelectric materials, including their structure and thermoelectric characteristics are discussed in brief. Additionally, it also discusses different methods described in the various literature regarding enhancing performance as well as recent advancements made in this area and this article emphasizes the relevance and importance of these developments in the context of urgent global energy challenges and highlights the crucial role that mid-temperature range thermoelectric materials will play in determining the future landscape of sustainable energy sources. To satisfy the practical demand, scientific research in the field of thermoelectricity still needs to be intensified, for this mid-temperature range, Chalcogenide-based thermoelectric materials play a very important role in the future.Graphical abstract

Perspectives on the production, structural characteristics and potential applications of bioplastics derived from polyhydroxyalkanoates

We identify a previously unresolved, unrecognized, and highly stable conformation of the protein kinase A (PKA) regulatory subunit RIα. This conformation, which we term the "Flipback" structure, bridges conflicting characteristics in crystallographic structures and solution experiments of the PKA RIα heterotetramer. Our simulations reveal a hinge residue, G235, in the B/C helix that is conserved through all isoforms of RI. Brownian dynamics simulations suggest that the Flipback conformation plays a role in cAMP association to the A domain of the R subunit.

Structural, capacitive and resistive characteristics of (Pb0.6Bi0.2Sm0.2)(Fe0.4Ti0.6)O3

Insights into the relation between crystal structure and deuterium desorption characteristics of Pd–Au–D alloys

Protein-protein interaction networks are very important for a wide range of biological processes. Crystallographic structures and mutational studies have generated a large number of information that allowed the discovery of energetically important determinants of specificity at intermolecular protein interfaces and the understanding of the structural and energetic characteristics of the binding hot spots. In this study we have used the improved MMPB/SA (molecular mechanics/Poisson-Boltzmann surface area) approach that combining molecular mechanics and continuum solvent permits to calculate the free energy differences upon alanine mutation. For a better understanding of the binding determinants of the complex formed between the FtsZ fragment and ZipA we extended the alanine scanning mutagenesis study to all interfacial residues of this complex. As a result, we present new mutations that allowed the discovery of residues for which the binding free energy differences upon alanine mutation are higher than 2.0 kcal/mol. We also observed the formation of a hydrophobic pocket with a high warm spot spatial complementarity between FtsZ and ZipA. Small molecules could be designed to bind to these amino acid residues hindering the binding of FtsZ to ZipA. Hence, these mutational data can be used to design new drugs to control more efficiently bacterial infections.