Interaction between catalysts for ammonia synthesis and oxygen

Reversible poisoning of the catalysts for ammonia synthesis by oxygen has been used to eliminate the pyrophoric nature of the reduced catalysts via their treatment by the mixtures of nitrogen, hydrogen or helium with oxygen at catalysis temperatures. Kinetic studies of oxygen sorption, catalyst structure, activity and stability to the secondary oxidation of the samples partially oxidized at various temperatures have revealed that the optimum temperatures to eliminate the pyrophoric effect are 673–773 K.

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, . , , , 673–773 K.

     

Electrocatalytic properties of the Ti(OH)3?Mo(III) system in the reduction of molecular nitrogen

Electrochemical reduction studies of dinitrogen catalyzed by Ti(OH)₃–Mo(III) in an alkaline methanol solution on a mercury cathode show that the maximum yield of hydrazine (4%) and ammonia (43%) is observed at 0.5 mA/cm² current density. In experimental conditions it corresponds to the zero-charge potential of sodium amalgam (–1.86 V).

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, T (OH)₃–Mo(III), , (43%) (4%) 0.5 mA/cm², .

     

Technique for determining the charge of cosmic ray nuclei by tracks in olivine crystals from meteorites

A technique for identifying the charge of cosmic ray nuclei, based on measurements of the length and average etch rate of tracks chemically etched in olivine crystals from the Marjalahti pallasite is described.     

Long-wavelength coherent radio radiation of cascades. I. Calculation within the cascade theory

The long-wavelength limit for radio radiation from high-energy particle cascades was calculated within the cascade theory taking into account the processes resulting in an negative excess. The results obtained were compared to the results of Monte Carlo numerical calculations.     

Experimental study of the radiation mechanism of the chiral action

The first results of the RAMBAS (Radiation Mechanism of Biomolecular Asymmetry) experiment on the study of the radiation mechanism of the effect on chiral molecules as a factor leading to chiral asymmetry formation are presented. It was found that irradiation with an electron flux from a radioactive source of a mixture of simple achiral materials initiates synthesis of the simplest amino acids; in a racemic mixture of complexes of amino acids and metals irradiation leads to asymmetric decomposition and chrial asymmetry formation. The results obtained can be essential for solving the problem of the origin of life and the formation of chiral asymmetry of the biosphere.     

Hybrid method for detecting cascades produced by ultrahigh-energy cosmic particles using a circumlunar satellite

A hybrid method for detecting cosmic rays and neutrino cascades using the radio method and the conventional method for detecting cascade particles was proposed. Cascades produced in the lunar soil near the surface by ultrahigh-energy cosmic rays and neutrinos in the energy range of 1 GeV–100 TeV, coming from above at different angles, were calculated. The calculated energy and angular distributions were extrapolated to the energy region of 10²⁰ eV. Using these results, the detection threshold was estimated as 10²⁰ eV which is approximately identical to the threshold for the radio detector previously considered by the authors.     

Synthesis of Bis(η5-cyclopentadienyldicarbonyliron)stannane Dichloride by Direct Oxidation of Tin and Reaction of This Compound and Its Analogs with Magnesium

A procedure was developed for preparing [Cp(CO)₂Fe]₂SnCl₂ by direct oxidation of tin with ⁵-cyclopentadienyldicarbonyliron chloride in polar solvents. The reaction kinetics was studied, and its scheme was suggested. Products of the reaction of magnesium with compounds R₂SnCl₂ [R = Cp(CO)₃Mo, Cp(CO)₃W, Cp(CO)₂Fe] were identified. The reaction mechanism was discussed.     

Ultrafast photodetectors based on the interaction of microwave radiation and a photoexcited plasma in semiconductors

The interaction of microwave radiation with the plasma in photoionized semiconductor photocells (CdS, CdSe) placed in waveguide measurement systems is investigated theoretically and experimentally. The interaction of the characteristic waveguide modes with a photoexcited semiconductor plasma is investigated. The dependence of the reflection coefficient and phase of the microwave radiation on the intensity of the optical radiation to be measured is obtained, and the influence of the surface of the semiconductor photocells on these parameters is investigated. A microwave photodetector design based on a millimeter-wave interferometer is developed. Zh. Tekh. Fiz. 68, 94–98 (November 1998)