Crystal structures and Hirshfeld surface analyses of bis(4,5-dihydrofuran-2-yl)dimethylsilane and (4,5-dihydrofuran-2-yl)(methyl)diphenylsilane

The title compounds, C10H16O2Si (1) and C17H18OSi (2), are classified as dihydrofurylsilanes, which show great potential as building blocks for various functionalized silanes. They both crystallize in the space group P\overline{1} in the triclinic crystal system. Analyses of the Hirshfeld surfaces show packing-determining interactions for both compounds, resulting in a polymeric chain along the [011] for silane 1 and a layered-interconnected structure along the b-axis direction for silane 2.

Automated prediction of lattice parameters from X-ray powder diffraction patterns

A key step in the analysis of powder X-ray diffraction (PXRD) data is the accurate determination of unit-cell lattice parameters. This step often requires significant human intervention and is a bottleneck that hinders efforts towards automated analysis. This work develops a series of one-dimensional convolutional neural networks (1D-CNNs) trained to provide lattice parameter estimates for each crystal system. A mean absolute percentage error of approximately 10% is achieved for each crystal system, which corresponds to a 100- to 1000-fold reduction in lattice parameter search space volume. The models learn from nearly one million crystal structures contained within the Inorganic Crystal Structure Database and the Cambridge Structural Database and, due to the nature of these two complimentary databases, the models generalize well across chemistries. A key component of this work is a systematic analysis of the effect of different realistic experimental non-idealities on model performance. It is found that the addition of impurity phases, baseline noise and peak broadening present the greatest challenges to learning, while zero-offset error and random intensity modulations have little effect. However, appropriate data modification schemes can be used to bolster model performance and yield reasonable predictions, even for data which simulate realistic experimental non-idealities. In order to obtain accurate results, a new approach is introduced which uses the initial machine learning estimates with existing iterative whole-pattern refinement schemes to tackle automated unit-cell solution.

Phosphorus Substitution Preference in Ye’elimite: Experiments and Density Functional Theory Simulations

Density functional theory (DFT) simulation has been recently introduced to understand the doping behavior of impurities in clinker phases. P-doped ye’elimite, a typical doping clinker phase, tends to form when phosphogypsum is used to manufacture calcium sulfoaluminate cement (CSA) clinkers. However, the substitution mechanism of P has not been uncovered yet. In this study, the influence of different doping amounts of P on the crystalline and electronic structure of ye’elimite was investigated using backscattered scanning electron microscopy–energy X-ray dispersive spectroscopy, X-ray diffraction tests, Rietveld quantitative phase analysis, and DFT simulations. Furthermore, the substitution preference of P in ye’elimite was revealed. Our results showed that increasing the doping amount of P increased the impurity contents in CSA clinkers, transforming the ye’elimite crystal system from the orthorhombic to the cubic system and decreasing the interplanar spacing of ye’elimite. Based on the calculation results of the defect formation energies, additional energies were required for P atoms to substitute Ca/Al atoms compared with those required for P atoms to substitute S atoms in both orthorhombic and cubic systems of ye’elimite. Combined calculation results of the bond length–bond order and partial density of states showed that the doped P atoms preferably substituted S atoms; the second possible substituted atoms were Al atoms, while there was only a slight possibility for substitution of Ca atoms. The substitution of P atoms for S atoms can be verified based on the elemental distribution in P-doped ye’elimite and the increasing residual CaSO4 contents. The transition of the crystal system and a decrease in the interplanar spacing for ye’elimite can also prove that the substitution of P atoms for Al atoms occurred substantially.

Structural and Fluorescence Properties of TiO2/Ag Nanoparticles Bilayers

The optical properties of the TiO2 / Ag hybrid nanoparticles were improved as the particles were prepared with a pulsed liquid laser ablation (PLAL) technology. The effect of number of pulses (450) on the structural and optical properties of nanoparticles prepared in distilled water (DW) as growth media was examined using a Q-Switched Nd-YAG laser with wavelength (1064 nm), ablation energy (530 mJ) and repetition rate (1Hz). The distance between the target and the lens (10 cm). Several were used for the diagnosis such as X-ray diffraction analysis, fourier infrared transformations, TEM assays and fluorescence of the prepared samples. The results of X-ray diffraction analysis of the silver nanoparticles deposited on a glass slide showed that the crystal system is cubic and polycrystalline, with the direction being dominated by [111] at the level of the crystals. The results of X-ray diffraction analysis of a solution of titanium dioxide nanoparticles deposited on a glass slide revealed the presence of a quadrangular crystal system, indicating the presence of titanium dioxide particles in (rutile), and that the prevailing trend for crystalline levels is [110]. The functional groups of (TiO2 / Ag) were determined in the liquid medium by the (FTIR) technique. Also, TEM images showed the presence of nanoparticles and microparticles in an almost spherical shape. The fluorescence measurement of (TiO2 / Ag) hybrid particles showed that through the graph the peak values of (284.1) and (418.3) nm. This is roughly identical to the absorption spectrum results of a hybrid silver and titanium dioxide nanoparticle solution.

Effect of Sintering Temperature on the Physical Properties of Ba0.6Sr0.4TiO3 Prepared by Solid-State Reaction

Barium Strontium Titanate (BST) ceramic materials are widely used in electronic devices due to their stable operation at high temperatures, high tunability, low tangent loss, low DC leakage, and alterable curie temperatures. While pure BST materials are usually produced at high sintering temperatures (1250 °C), there are limited studies on the temperature and duration of the sintering process to produce pure BST, synthesised from micro or even nano-sized raw materials. This study aims to determine the effective sintering temperature for producing pure BST material using a mixture of raw materials with a mean particle size of 0.4 μm after milled for 58 hours. The BaCO3, SrCO3, and TiO2 materials as raw materials for Ba0.6Sr0.4TiO3 synthesis were milled for 58 hours to produce a homogeneous mixture with a mean particle size of 0.4 μm. Sintering was carried out in a temperature range of 500-1100 °C for 1 hour. This study investigates the impact of sintering temperature on the physical properties and the purity of Ba0.6Sr0.4TiO3 powder using the x-ray diffraction method. The results showed that the Ba0.6Sr0.4TiO3 phase was formed at a sintering temperature of 700 °C. Pure BST material was formed at the sintering temperature of 1000 °C with a crystallite size of 41 nm. Whereas at a higher sintering temperature (1100 °C), the pure BST material formed produced a larger crystallite, sized at 43 nm with cubic structure. The synthesis temperature and duration recorded in this research are lower than recorded in the BST material preparation using the solid-state method. The results of this study indicate that the sintering temperature greatly affects the purity, crystal system and crystallite size of the Ba0.6Sr0.4TiO3 material produced. The sintering temperature of 1100 °C produces Ba0.6Sr0.4TiO3 material with the best physical properties because it has a cubic-shaped crystal system and the largest crystal size.