A procedure for the controlled barrier layer removal is suggested in this work which provides the preparation of anodic alumina membrane with specified pore diameter and permeance. Optimal conditions ...for barrier layer removal which give membranes with high gas permeance of 400 m
3
/(m
2
atm h) by nitrogen and breaking strength of up to 440 ± 40 MPa, which is allowable for their operation in baromembrane processes, are developed.
A straightforward and facile procedure for the fabrication of superhydrophobic luminescent 3D nanomaterials was developed. Chemical modification of ultra-lightweight highly porous nanostructured ...aluminum oxyhydroxide (NOA) monoliths in 8-hydroxyquinoline vapors resulted in the formation of tris(8–hydroxyquinoline)aluminum on the surface of NOA nanofibrils. The original shape and size of the initial NOA monolith and its internal 3D nanostructure were completely preserved during the modification. Surface modified NOA samples demonstrated intense green luminescence as well as superhydrophobicity, the water contact angle being ~153°, the sliding angle ~6° and contact angle hysteresis ~8°. We believe that an unusual combination of properties inherent in the synthesized material will be advantageous for the design of water-proof self-cleaning photonic devices.
Display omitted
•Highly porous luminescent alumina-based monolithic material was prepared.•Gaseous 8-oxyquinoline reacts with fibrous alumina, forming complexes on its surface.•Fibrous alumina modified with 8-oxyquinoline acquires superhydrophobic property.
Samples of the Chelyabinsk meteorite fallen in February 15, 2013, near Chelyabinsk, Russia, are analyzed by Raman spectroscopy. Olivines (forsterite), orthopyoxenes (enstatite), plagioclases ...(albite), iron oxides and sulfides, as well as calcite and, possibly, parisite were identified among mineral phases. Results were verified using scanning electron microscope with an energy-dispersive system (SEM-EDX). Data were compared with available materials on calcites from ordinary meteorites.
Effects caused by the type of solvent used for supercritical drying on the properties of methyltrimethoxysilane-based aerogels were studied. All of the aerogel samples studied were found to be ...hydrophobic and to efficiently adsorb nonpolar organic compounds.
The influence of controllable amount of water admixture (up to 0.5 w.%) in benzoic acid on the proton exchange process of X-cut congruent lithium niobate was studied in this paper by means of mode ...spectroscopy, optical microscopy, optical profilometry, atomic force microscopy, XRD, and chemical etching. It has been determined that addition of 0.5 w.% Н
2
О to benzoic acid increases proton exchange rate and changes phase composition and number of defects of proton exchanged layer in lithium niobate.
The phase structure of planar and channel, un-annealed and annealed proton exchanged waveguides made in benzoic acid and benzoic acid + lithium benzoate melts on Z cut of congruent lithium niobate ...crystal was investigated using mode spectroscopy, IR spectroscopy, XRD, SEM, AFM, microindentation, and wet etching techniques. In un-annealed waveguides, three layers (probably β
2
, β
1
, and κ
2
phases) can be distinguished. At least two different structural layers are present in annealed channel waveguides. Proton exchange (225
o
C, 28 h) in benzoic acid + 3 mol.% of lithium benzoate leads to formation of κ
2
phase and a thin layer of α phase.
In the present paper we report utilization of porous and barrier type of titania films formed by anodic oxidation as an active layer of the memristive element in the Au-TiO2-Ti structure. The ...comparison of semiconductor properties of porous and barrier type of anodic titania was performed via the Mott-Schottky technique. The obtained memristive elements show the bipolar type of switching governed by Schottky barrier screening. For barrier type film the switching potential is equal to -1.5 V and the ratio of resistance in OFF and ON stage (Roff/Ron) is equal to 34. For porous type films, the switching potential is equal to -0.6 V and Roff/Ron = 131. Moreover, we observed the dependence of Roff/Ron on the voltage sweeping rate, which can be explained by the limitation in diffusion of oxygen vacancies through the oxide layer.
Pr sub(2)CuO sub(4)-Ce sub(0.9 )Gd sub(0.1)O sub(1.95) (PCO-GDC) composites screen printed on Ce sub(0.9)Gd sub(0.1)O sub(1.95) (GDC) electrolyte were considered as a cathode material for ...intermediate temperature solid oxide fuel cells (IT-SOFCs). Phase composition, microstructure and electrochemical properties were investigated by X-ray powder diffraction (XRD), scanning electron microscopy and AC impedance spectroscopy, respectively. The oxygen reduction on porous PCO-GDC electrode applied on CGO electrolyte was studied in a symmetrical cell configuration by AC impedance spectroscopy at OCV conditions at 670-730 degreesC and Po sub(2) = 10 super(-2) - 0.21 atm. The charge transfer process and the dissociation of adsorbed molecular oxygen were found to be rate-determining steps of the oxygen reduction reaction. Results reveal that both GDC addition and electrode morphology have strong influence on area specific resistance (ASR) of the electrode/electrolyte interface. The lowest ASR value of 0.41 Omega cm super(2) was achieved for the composition containing 33 wt.% GDC at 700 degreesC in air. The data obtained allow to consider the PCO-GDC33 composite as a promising cathode material for IT-SOFCs.
PDF
