Properties of Al2O3: nc-Si nanostructures formed by implantation of silicon ions into sapphire and amorphous films of aluminum oxide

Physics of the Solid State - Photoluminescence, infrared Fourier spectroscopy, Raman scattering, transmission electron microscopy, and electron diffraction were used to study the luminescent,...     

Measurement of cumulative-photon spectra at high transverse momenta in 12C9Be interactions at an energy of 3.2 GeV per nucleon

For ¹²C⁹Be interactions at a kinetic beam energy of 3.2 GeV per nucleon, the spectra of photons at laboratory angles in the range 55°–73° were measured off the kinematical region available to the interaction of single nucleons within colliding nuclei. The use of a fast trigger for selecting events involving the production of high-transverse-momentum photons made it possible to measure spectra off the kinematical boundary of four-nucleon interaction. It is shown that the proposed procedure is adequate to the problem of searches for and investigation of flucton-flucton interaction. In the kinematical region where flucton-flucton interaction can manifest itself, the cross sections in question are on the same order of magnitude as respective model predictions. In order to draw definitive conclusions on the role of flucton-flucton interaction, it is highly desirable to extend the angular range of the measurements toward smaller angles.     

Capabilities to improve corrosion resistance of fuel claddings by using powerful laser and plasma sources

The treatment conditions of fuel claddings of the E110 alloy by using powerful UV or IR laser radiation, which lead to the increase in the corrosion resistance at the high-temperature (T = 1100°C) oxidation simulating a loss-of-coolant accident, are determined. The possibility of the complete suppression of corrosion under these conditions by using pulsed laser deposition of a Cr layer is demonstrated. The behavior of protective coatings of Al, Al₂O₃, and Cr planted on steel EP823 by pulsed laser deposition, which is planned to be used in the BREST-OD-300, is studied. The methods of the almost complete suppression of corrosion in liquid lead to the temperature of 720°C are shown.     

Effect of aluminum vacancies on the H2O2 or H2O interaction with a gamma-AlOOH surface. A solid-state DFT study

The adsorption of a single H₂O₂ or H₂O molecule on a family of periodic slab models of γ-AlOOH is studied by solid-state DFT. The single H₂O₂ or Н₂О molecule interacts with the perfect (010) slab by intermolecular hydrogen bonds (H-bonds). In the models of γ-AlOOH with oxygen and aluminum vacancies, H₂O₂ or Н₂О also forms covalent O∙∙∙Al bonds. The energies of covalent O∙∙∙Al and H-bonds are estimated by a combined approach based on simultaneous consideration of the total binding energies with BSSE correction and empirical schemes of the Н-bond energy evaluation. The O∙∙∙Al bond energy ranges from ~75 to ~156 kJ mol⁻¹. The total energy of H-bond interactions in the case of H₂O₂ exceeds that of Н₂О by ~30 kJ mol⁻¹ for all considered slab models. In contrast to Н₂О, a H₂O₂ molecule always forms two H-bonds as the proton donor. The energy of these bonds noticeably increase on defect γ-AlOOH surfaces in comparison with the perfect slab due to formation of short (strong) H-bonds by adsorbed H₂O₂.     

Reaction of acetylenedicarboxylic acids esters with 4,5-dihydro-1<Emphasis Type="Italic">H</Emphasis>-pyrazole-1-carbothioamides and 3,4,5,6-tetrahydro-2<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazepine-3-thiones

The reactions of dimethyl acetylenecarboxylate with 3,4,5,6-tetrahydro-2H-1,2,4-triazepine-3-thiones and 4,5-dihydro-1H-pyrazole-1-carbothioamides are convenient methods for the synthesis of 7,8-dihydrothiazolo[3,2-b][1,2,4]triazepin-3-ones derivatives and methyl esters of (2Z)-[2-(4,5-dihydro-1H-pyrazol-1-yl)-4-oxo-1,3-thiazol-5(4H)-ylidene]acetic acids, respectively. The reaction of methyl propynoates with 4,5-dihydro-1H-pyrazole-1-carbothioamides or with 5,5,7-trimethyl-2,4,5,6-tetrahydro-3H-1,2,4-triazepine-3-thione gives 2-(4,5-dihydro-1H-pyrazol-1-yl)-4H-1,3-thiazin-4-ones.     

Electrocatalytic fluoroalkylation of olefins

Under electrocatalysis conditions, the perfluoroalkylation of α-methylstyrene by the nickel complex NiBr₂bipy proceeds with the formation of dimeric products of addition of perfluoroalkyl radicals to the double bond.     

Enthalpies of elementary chain propagation steps in the oxidation of organic compounds

A calculation of the enthalpies of elementary steps of the intra- and intermolecular chain propagation for model oxidation reactions of ethers, esters, ketones and hydrocarbons has been carried out. The heats of the intermolecular and intramolecular transfer of free valence with participation of peroxy radicals and C−H bond of the oxygen-containing compounds are shown to be comparable.     

On the stability of Al<Subscript>13</Subscript> Keggin cation in aqueous hydrogen peroxide solutions

We report the first attempt to study the behavior of the [AlO₄Al1₂(OH)₂₅(H₂O)₁₁]⁶⁺ (Al₁₃) Keggin cation (KC) in water–peroxide solutions. Addition of hydrogen peroxide into an aqueous solution containing the Al₁₃ KC reduces pH due to the acidity of hydrogen peroxide. According to the ²⁷Al NMR studies of water–peroxide solutions prepared just before the NMR experiment, with their pH adjusted to the initial value of 5.5 with aqueous NaOH, the Al₁₃ KC concentration decreases immediately once hydrogen peroxide is added to the initial system. Addition of 18.2 wt % hydrogen peroxide to the initial 0.88 mM Al₁₃ solution gives rise to a fourfold decline in Al₁₃ polyoxo cation concentration to 0.22 mM. Then, the KC concentration in the test system remains unchanged for 1 week. Large hydrogen peroxide amounts (27.9 wt % or higher) added to the initial system almost completely degrade the KC. Sodium sulfate added to the initial water–peroxide solution of Al₁₃ chloride where the hydrogen peroxide concentration is 5.5 wt % precipitates the earlier described Al₁₃ sulfate [AlO₄Al₁₂(OH)₂₅(H₂O)₁₁](SO₄)₃ · 16H₂O, where the aluminum polyoxo cation does not contain coordinated hydrogen peroxide molecules, peroxo or hydroperoxo groups as shown by X-ray diffraction.     

Selective Targeting of Tumor and Stromal Cells By a Nanocarrier System Displaying Lipidated Cathepsin B Inhibitor

Cathepsin B (CtsB) is a lysosomal cysteine proteinase that is specifically translocated to the extracellular milieu during cancer progression. The development of a lipidated CtsB inhibitor incorporated into the envelope of a liposomal nanocarrier (LNC‐NS‐629) is described. Ex vivo and in vivo studies confirmed selective targeting and internalization of LNC‐NS‐629 by tumor and stromal cells, thus validating CtsB targeting as a highly promising approach to cancer diagnosis and treatment.     

Synthesis and reactions of 3-halomethyl-substituted oxazine N-oxides

A series of 3-halomethyl-5,6-dihydro-1,2-oxazine N-oxides (halogen = Cl, Br, I) is prepared from 4-phenyl-3,6,6-trimethyl-5,6-dihydro-4H-oxazine N-oxide by means of a silylation/halogenation sequence. The obtained halogenated N-oxides undergo reactions typical of cyclic six-membered nitronates including 1,3-dipolar cycloaddition, addition of nucleophiles, and substitution of the halogen by C-, S-, and N-nucleophiles.