Study of the process of PbS nanocrystal formation in lead stearate and behenate Langmuir-Blodgett films by electron diffraction and x-ray reflectometry

Special features of the formation of PbS nanocrystals in Langmuir-Blodgett (LB) films of lead stearate and behenate under the action of H₂S are studied. It is shown that structural transformations in a multilayered LB film can be controlled using electron diffraction patterns of the oblique-texture type and x-ray reflectometry data.     

Conducting polyaniline prepared by the laccase-catalyzed method in a water dispersion of sodium dodecylbenzenesulfonate micellar solution

In the present work, physico-chemical properties of conducting polyaniline (PANI) prepared by laccase-catalyzed oxidative polymerization in water dispersions of sodium dodecylbenzenesulfonate micellar solutions were studied. The polymer was characterized using FTIR spectroscopy, cyclic voltammetry, termogravimetry, transmission electron microscopy, and electron diffraction. The antistatic properties of the obtained polyaniline were also studied.     

Epitaxy of ZnO Films on the (0001) Surface of Crystalline Substrates of Lanthanum–Magnesium Hexaaluminate LaMgAl11O19

Crystallography Reports - The morphology and structure of heteroepitaxial ZnO films deposited on the (0001) surface of crystalline substrates of lanthanum–magnesium hexaaluminate LaMgAl11O19...     

Microstructural Features of Poly(N-Vinylpyrrolidone)−La(NO3)3 ⋅ 6H2O Hydrogel

Crystallography Reports - The structural features of the poly(N-vinylpyrrolidone)–La(NO3)3 ? 6H2O composite hydrogel were studied by scanning and transmission electron microscopy. The...     

Interaction between nanosized crystalline components of a composite based on <Emphasis Type="Italic">Acetobacter xylinum</Emphasis> cellulose and calcium phosphates

A composite consisting of two nanosized biocompatible components, Acetobacter xylinum cellulose and calcium phosphate, is prepared through aggregation in an aqueous suspension. The structures of initial components and composite are investigated by the methods of X-ray and electron diffraction and electron microscopy. The mineral component consists of two crystalline phases, hydroxyapatite and whitlockite (magnesium-containing tricalcium phosphate), which are nanosized platelike crystals. The composite preserves the crystalline structures of initial calcium phosphates and cellulose. In the course of composite formation, hydroxyapatite and whitlockite crystallites are adsorbed on the surfaces of nanofibrillar cellulose ribbons. Whitlockite nanocrystals are predominantly deposited on the surface of cellulose ribbons. The mutual orientation of the surfaces of crystalline structures of cellulose and two types of calcium phosphates, hydroxyapatite and whitlockite, is analyzed by means of computer simulation, and the variants of mutual arrangement of their surfaces during formation of the interfacial boundary are suggested.     

75LiF + 25SmF3 Eutectic Composite and Ionic Conductivity of SmF3 near the Polymorphic α–β Transition

Crystallography Reports - 75 mol % LiF + 25 mol % SmF3 eutectic composite is obtained by fusing components in a CF4 atmosphere. The composite is multiphase and consists of β-SmF3 (sp. gr....     

Transmission electron microscopy of Ca oxide nano- and microcrystals in α-tricalcium phosphate prepared by sintering of β-tricalcium phosphate

Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to study the porous and non-porous α-tricalcium phosphate (α-Ca₃(PO₄)₂, α-TCP) prepared through a sintering procedure at 1200–1400 °C of β-tricalcium phosphate (β-Ca₃(PO₄)₂, β-TCP). The interpretation of experimental and calculated X-ray and electron diffraction patterns showed that the final product at 1400 °C was primarily α-TCP but roughly 3.0–8.0 wt.% of the starting β-TCP phase and up to 8.0 wt.% of CaO were in the final product. TEM images and electron diffraction patterns showed that the CaO phase – formed by decomposition of TCP – exists as micron-sized areas of various oriented nanocrystals embedded into the bulk α-TCP material and also as self-standing spherulite particles of a few microns in size. Surprisingly, formation of CaO from TCP decomposition occurred at temperatures below those predicted from the phase diagram of the CaO–P₂O₅ system.     

Noise simulation of aircraft engine fans by the boundary element method

Numerical simulation results of the civil aircraft engine fan stage noise in the far field are presented. Non-steady-state rotor–stator interaction is calculated the commercial software that solves the Navier–Stokes equations using differentturbulence models. Noise propagation to the far acoustic field is calculated by the boundary element method using acoustic Lighthill analogies without taking into account the mean current in the air inlet duct. The calculated sound pressure levels at points 50 m from the engine are presented, and the directional patterns of the acoustic radiation are shown. The use of the eddy resolving turbulence model to calculate rotor–stator interaction increases the accuracy in predicting fan stage noise.     

Increase of polymeric chain conjugation length in UV irradiated monolayer of hydroxyalkadiynyl N-arylcarbamate derivative

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