Synthesis and acylation of O,O-Dihexyl(dioctyl)-[1-hydroxy-3-(ethyl, diethylamino)-2,2-dimethylpropyl]phosphonates

Reaction of dialkyl phosphites with 3-ethylamino- or 3-diethylamino-substituted aldehydes results in the corresponding 3-amino-1-hydroxyalkylphosphonates. The composition and structure of the obtained compounds were confirmed by elemental analysis, NMR spectroscopy and chemical transformations.     

Wavefront reconstruction of an optical vortex by a Hartmann-Shack sensor

Reconstruction the phase front of a vortex laser beam is conducted by use of a Hartmann-Shack wavefront sensor. The vortex beam in the form of the Laguerre-Gaussian LG(0)(1) mode is generated with the help of a spiral phase plate. The new reconstruction technique based on measured wavefront gradients allows one to restore the singular phase surface with good accuracy, whereas the conventional least-squares approach fails.     

New Data on the Isomorphism in Eudialyte-Group Minerals. V: Crystal Structure of an Intermediate Member of the Manganoeudialyte‒Ilyukhinite Isomorphous Series

Crystallography Reports - The crystal structure of a high-symmetry representative of the eudialyte group from the Norra Kärr massif (Sweden) has been investigated by X-ray diffraction analysis...     

Crystal Structure of Cl-Deficient Analogue of Taseqite from Odikhincha Massif

An eudialyte group mineral, found in pegmatites of the Odikhincha massif (the northern part of the Siberian platform), has been investigated using X-ray diffraction, IR spectroscopy, and Raman spectroscopy. The mineral is characterized by a high strontium content and a low chlorine content. It has a trigonal unit cell with the following parameters: a = 14.2700(6) Å and c = 30.057(1) Å; V = 5300.6(1) ų; sp. gr. R3m. The structure has been refined to R = 0.047 in the anisotropic approximation of atomic displacements using 1697F > 4σ(F). The idealized formula (Z = 3) was found to be Na₁₂Sr₂Ca₆Fe ₃ ²⁺ Zr₃NbSi₂₅O₇₂(OH,O)₄Cl(Н₂О)_0.2. The chemical composition and structure of this mineral are close to those of taseqite; however, it differs from the holotype sample by a low chlorine content and peculiarities of cation distribution over basic structure sites. A comparative analysis of strontium-rich eudialytes has revealed their important crystallochemical feature: selective concentration of strontium in the N4 site. Thus, taseqite, along with heterophyllosilicates, may play a role of strontium concentrator in agpaitic pegmatites.     

Effects of electron inelastic transport through the potential relief of a spin dimer in a magnetic field

The influence of inelastic effects on electron quantum transport through the potential relief of a dimer system was studied by exact solution of the Schrodinger equation. The nature of this problem is due to the coherent superposition of the different potential profiles through which the spin-polarized electron tunnels. It was found that the low magnetic field initiates new peaks of resonant tunneling. In high magnetic fields, the transport of electrons with opposite spin polarization is qualitatively different.     

Pulse-detonation burner unit operating on natural gas

The possibility of controlled cyclic deflagration-to-detonation transition within a length of 2.5–3.0 m in an open-end tube (94 mm in diameter) with separate continuous supply of natural gas and air was demonstrated for the first time. Based on experimental studies, a workable pulse detonation burner, a prototype of new generation of industrial burners, was developed. It can produce a combined effect on the objects blown on with combustion products—shock-wave (mechanical) and thermal.     

Formation of nitrogen oxides in detonation waves

Based on detailed kinetic calculations and experimental data, it is demonstrated that the emission of nitrogen oxides from detonation burner units (DBUs) is significantly lower than that from powerful conventional burners with similar characteristics. Under certain conditions, realized largely in DBUs with rotating detonation, the main component of the nitrogen oxides may turn out to be N₂O.