Thermal behavior of ammonium-containing titanium and germanium fluoride complexes (NH4)4Li2(AF6)3 and NH4NaAF6 (A = Ge or Ti)

The compounds (NH₄)₄Li₂A₃F₁₈ and NH₄NaAF₆ (A = Ge or Ti) were studied thermogravimetrically. These fluoro complexes are thermolyzed in the range 230–450°C. Measurements on a differential scanning microcalorimeter revealed reversible phase transitions in NH₄NaAF₆ at T ₁ = 126°C and T ₂ = 111°C. Original Russian Text ? T.F. Antokhina, I.N. Flerov, N.N. Savchenko, T.A. Kaidalova, E.B. Merkulov, L.N. Ignat’eva, V.D. Fokina, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 4, pp. 639–643.     

Investigation into the significant effect of CuO additive on the synthesis of ZrSiO4: phase formation and crystallization at low temperature

Journal of Thermal Analysis and Calorimetry - The ZrSiO4 has been synthesized with CuO as mineralizer by sol–gel route at low temperature. The mineralization effect of the CuO on mechanism of...     

Initial stages of soot formation in thermal pyrolysis of acetylene. I. Mechanism for homogeneous pyrolysis of acetylene

A probable mechanism for the homogeneous pyrolysis of acetylene, using carbene reactions, is considered. Analysis of the energetics for the probable mechanism of the initiation reactions shows the rearrangement C₂H₂CCH₂ to be the most probable. Using the energetic barriers for simple carbene reactions and formation enthalpies for more complicated carbenes, we evaluated the activation energies for the reactions mechanism. The vibrational excitation of the products of carbene reactions is taken into account. Calculations of the acetylene conversion kinetics and yields of the main gas-phase pyrolysis products, based on the carbene molecular mechanism, show significantly better agreement with available experimental data as compared to those based on traditional radical mechanisms. The calculated time for the appearance of aromatic products is close to the measured induction times for the appearance of soot particles.     

Probability distribution of the breakdown electric fields of polymer dielectrics

The probability distribution is derived for the breakdown electric field of polymers, treated as inhomogeneous dielectrics. The extremal distribution and the Weibull distribution are shown to be particular cases of the result found. The experimental results found with low-pressure polyethylene and polyethylene, Styroflex, and polyethylene terephthalate films are consistent with the theoretical probability distribution found for the breakdown electric field.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 49–55, January, 1971.     

The use of small computers in large-scale activation analysis

This paper describes simple algorithms for evaluating gamma-ray spectra, readily applicable to small computers. A comparative assessment of the accuracy of the existing programs for experimental data analysis is presented. The use of “Nairi-K” computers suitable for “on-line” operation with multichannel analyzers enables as many as 300 element determinations to be carried out in a 7-hour working day.