Experimental and field applications of nanotechnology for enhanced oil recovery purposes: A review

Pyrochlores belong to a numerous family of crystalline materials with a rich variety of technologically important functional properties and developed structural diversity of possible transformation...

Structural Diversity of Ordered Pyrochlores

A new member of fluorooxoborates, Li2Na0.9K0.1B5O8F2, was obtained in the sealed system, and single-crystal X-ray diffraction was used to determine its structure. It contains a three-dimensional framework stacking of [B5O8F2]3– layers extending into the ac plane. Detailed structural comparisons among all of the fluorine-containing alkali-metal borates suggest that the [B5O8F2]3– layer composed of the new fundamental building blocks B5O10F2 represents a new structure type of fluorooxoborate. The IR spectrum verifies its structural validity. The deep-ultraviolet spectral measurement shows that it has no obvious absorption in the range of 180–300 nm, and its cutoff edge is under 180 nm. In addition, theoretical calculations were done to help us understand its electronic structure and optical properties.

A Member of Fluorooxoborates: Li2Na0.9K0.1B5O8F2 with the Fundamental Building Block B5O10F2 and a Short Cutoff Edge.

Structure analysis and electronic properties of ATe4+0.5Te6+1.5-xM6+xO6 (A=Rb, Cs, M6+=Mo, W) solid solutions with β-pyrochlore structure

Membranes are a promising technology for bulk CO2 separation from natural gas mixtures due to their numerous advantages. Despite the numerous fundamental studies on creating better quality membrane efficiency, scaling up the research work for field testing requires huge efforts. The challenge is to ensure the stability of the membrane throughout the operation while maintaining its high performance. This review addresses the key challenges in the application of polymeric technology for CO2 separation, focusing on plasticization and aging. A brief introduction to the properties and limitations of the current commercial polymeric membrane is first deliberated. The effect of each plasticizer component in natural gas towards membrane performance and the relationship between operating conditions and the membrane efficiency are discussed in this review. The recent technological advancements and techniques to overcome the plasticization and aging issues covering polymer modification, high free-volume polymers, polymer blending and facilitated transport membranes (FTMs) have been highlighted. We also give our perspectives on a few main features of research related to polymeric membranes and the way forwards. Upcoming research must emphasize mixed gas with CO2 including minor condensable contaminants as per real natural gas, to determine the competitive sorption effect on CO2 permeability and membrane selectivity. The effects of pore blocking, plasticization and aging should be given particular attention to cater for large-scale applications.

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Recent Advances of Polymeric Membranes in Tackling Plasticization and Aging for Practical Industrial CO2/CH4 Applications—A Review

Features of the electronic structure and photocatalytic properties under visible light irradiation for RbTe1.5W0.5O6 with β-pyrochlore structure

Single crystals of CsNbMoO6 were grown from solution in melt, and their crystal structure was solved by X-ray diffraction (R[I > 2σ(I)]1 = 0.0386). Crystals were cubic, а = 10.41039(8) A, Z = 8, space group \(F\bar 43m\). The synthesized crystals were shown to exhibit the second harmonic generation effect, which confirmed the absence of an inversion center in the structure. The structure was built of MO6 (M = Nb, Mo) octahedra, which share all vertices to form a three-dimensional framework where niobium and molybdenum atoms are randomly distributed. Framework interstices accommodate cesium ions. Crystals of CsNbMoO6 can be considered as pseudo-symmetric with respect to space group \(Fd\bar 3m\) due to a small shift of some oxygen atoms relative to the regular system of points in this group.

Crystal structure of CsNbMoO6

Zinc oxide nanoparticles were obtained by plasma-enhanced chemical vapor deposition (PECVD) under optical emission spectrometry control from elemental high-purity zinc in a zinc–oxygen–hydrogen plasma-forming gas mixture with varying deposition parameters: a zinc source temperature, and a reactor temperature in a deposition zone. The size and morphological parameters of the zinc oxide nanopowders, structural properties, and homogeneity were studied. The study was carried out with use of methods such as scanning electron microscopy, X-ray structural analysis, and Raman spectroscopy, as well as statistical methods for processing and analyzing experimental data. It was established that to obtain zinc oxide nanoparticles with a given size and morphological characteristics using PECVD, it is necessary (1) to increase the zinc source temperature to synthesize more elongated structures in one direction (and vice versa), and (2) to decrease the reactor temperature in the deposition zone to reduce the transverse size of the deposited structures (and vice versa), taking into account that at relatively low temperatures instead of powder structures, films can form.

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Influence of Temperature Parameters on Morphological Characteristics of Plasma Deposited Zinc Oxide Nanoparticles

Impurity defect absorption and photochromic effect in KNbWO6

Complexes of 1-(2-R(F, CH3, Cl)-phenyl)-1,4-dihydro-5H-tetrazole-5-thiones with cadmium chloride: Synthesis, molecular, crystal structures and computational investigation approach.

D.G. Fukina

Papers

Features of the electronic structure and photocatalytic properties under visible light irradiation for RbTe1.5W0.5O6 with β-pyrochlore structure

Crystal structure of CsNbMoO6

Influence of Temperature Parameters on Morphological Characteristics of Plasma Deposited Zinc Oxide Nanoparticles

Impurity defect absorption and photochromic effect in KNbWO6

Complexes of 1-(2-R(F, CH3, Cl)-phenyl)-1,4-dihydro-5H-tetrazole-5-thiones with cadmium chloride: Synthesis, molecular, crystal structures and computational investigation approach.