Solid-state Water-mediated Transport Reduction of Nanostructured Iron Oxides

The Fe²⁺/Fe³⁺ ratio in two-dimensional iron oxide nanosructures (nanolayers with a thickness of 0.3–1.5 nm on silica surface) may be precisely controlled using the transport reduction (TR) technique. The species –O–Fe(OH)₂ and (Si–O–)₂–FeOH forming the surface monolayer are not reduced at 400–600°C because of their covalent bonding to the silica surface, as demonstrated by Mössbauer spectroscopy. Iron oxide microparticles (microstructures) obtained by the impregnation technique, being chemically unbound to silica, are subjected to reduction at T 500°C with formation of metallic iron in the form of -Fe. Transport reduction of supported nanostructures (consisting of 1 or 4 monolayers) at T 600°C produces bulk iron(II) silicate and metallic iron phases. The structural-chemical transformations occurring in transport reduction of supported iron oxide nanolayers are proved to be governed by specific phase processes in the nanostructures themselves.     

Magnetic Dipole Moment from a One‐Kiloton Underground Nuclear Explosion in a Cavity

This paper reports the results of numerical modeling of the magnetic dipole moment produced by displacement of the Earth's magnetic field in a onekiloton underground nuclear explosion in a cavity. It is shown that with increase in cavity size, the magnetic dipole moment increases, reaching 10⁷ A · m², which is approximately 200 times the magnetic dipole moment from a camouflet explosion. A factor of 100 decrease in the initial air density in cavities with radii of 10 and 20 m results in a reversal of the direction of the magnetic dipole moment vector.     

Dental biothermophotonics: A quantitative photothermal analysis of early dental demineralization

Photothermal Radiometry (PTR) is applied as a safe, non-destructive, and highly sensitive tool for the detection of early enamel demineralization. Teeth were treated sequentially with artificial demineralization to simulate controlled mineral loss. PTR frequency scans were performed at the same surface spot before and after each treatment. After 4 days of demineralization, the signal changed significantly compared to sound enamel scans. A coupled diffuse-photon-density-wave and thermal-wave theoretical model was developed to describe the biothermophotonic phenomena in the turbid medium consisting of a demineralised layer, sound enamel, and dentin. As a result of the fittings, thermal and optical properties of the layers were obtained.     

New Functional Detergents Based on Imidazole Derivatives – Effective Reagents for Cleavage of the Esters of Organic Acids

A detailed kinetic and thermodynamic analysis showed that the new functional detergents in which the head part contains an imidazole ring with oximate, amidoximate, and hydroxamate -nucleophilic fragments linked to it are very powerful supernucleophilic systems in the cleavage of organophosphorus compounds.     

Approximate selection rule for orbital angular momentum in atomic radiative transitions

We demonstrate that radiative transitions with Δl=−1$\mathrm{\Delta }l=-1$ are strongly dominating for all values of n and l  , except small region where l?n$l?n$.     

Generation and registration of disturbances in a gas flow. 2. Experiments with arrays of tubular microheaters and microsensors

Aerodynamic experiments with arrays of conducting microtubes are performed, and their electric properties are determined. Sensitivity of microtubes located on the model surface to disturbances of the gas flow is revealed. It is demonstrated that such microtubes can be used both for registration of disturbances being introduced and as disturbance generators. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 50, No. 3, pp. 112–117, May–June, 2009.     

Mathematical Modeling of the Melting Process of Silicate Materials in a Plasma Reactor

Russian Physics Journal - Results of mathematical modeling of the melting process of silicate materials in a plasma reactor are presented. Quartz sand containing up to ~98 wt% SiO2 was used as a...     

Uncommon condensations of 1,2,3-triketone 2-oximes with o-phenylenediamine

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Oxidation of methyl phenyl sulfide by carbamide peroxide in the presence of activators

The oxidation of methyl phenyl sulfide by carbamide peroxide in water and water–ethanol mixtures proceeds at the same rates as oxidation by hydrogen peroxide. In the presence of ammonium bicarbonate, the reaction proceeds through a pathway including HCO₄^- as a more active oxidizing agent than H₂O₂.