Polygonization in high-purity rolled (001)[110] tungsten single crystals

Electron microscopy is used to study changes in the dislocation structure of high-purity rolled (001)[110] tungsten single crystals during short-term high-temperature annealings. The effects of the annealing temperature and time on the formation of low-angle boundaries are investigated. Local defects, which are similar to those detected earlier upon annealing in the structure of molybdenum single-crystal ribbons, are found to form and dissociate upon annealing. These defects are concluded to have a dislocation nature.     

Oxidation of Formic and Oxalic Acids in an Electrodeless Electrochemical Reaction

Decomposition of formic and oxalic acid and of sodium formate and sodium oxalate (0.1 M solutions) in an electrodeless electrochemical reaction was studied. The oxidation kinetics was analyzed in terms of the previously developed model. The decomposition yields of formic acid and sodium formate are 0.5 and 1 molecule/(100 eV), respectively, which is comparable with the radiation-chemical decomposition yield, taking into account the installation efficiency.     

Elementary stages and kinetics of phenoxide radicals reactions with cobalt and iron ions

Introduction of cobalt acetylacetonate to the solution containing phenoxide radicals has led todecelerating their termination. Cobalt acetylacetonate reactivity is dual, it has acted as an inhibitor when introduced in a certain concentration to the low-temperature oxidizing mixture.     

Mechanisms of Photoreactions of 2,6-Diphenyl-1,4-benzoquinone and Its Dimer in Different Solvents

Russian Journal of Physical Chemistry A - An investigation of 2,6-diphenyl-1,4-benzoquinone (a class of substituted benzoquinones) and its dimer is performed to study the effect the solvents have...     

Thermodynamic properties of cerium mononitride

Data on the thermodynamic properties of cerium mononitride CeN in the solid state are analyzed. Relations approximating the temperature dependence of the thermodynamic functions of CeN(cr.) in the temperature range of 298.15–2900 K are obtained. Using the relations of thermodynamics known for this temperature range, the thermodynamic functions of cerium mononitride (entropy, Gibbs energy, and enthalpy variation) are calculated. The resulting data is entered into the database of the IVTANTHERMO software package and is used to analyze the thermal stability of CeN(cr.), and to estimate its boiling point at atmospheric pressure.     

Interaction of laser radiation with a low-density structured absorber

A theoretical model is proposed for computing simulations of laser radiation interaction with inhomogeneous foam materials doped with heavy elements and undoped materials. The model satisfactorily describes many experiments on the interaction of the first and third harmonics of a 200 J pulsed PALS iodine laser with low-density porous cellulose triacetate targets. The model can be used to analyze experimental data and estimate the reality of experimental results.     

Refining the thermodynamic functions of scandium triflouride ScF<Subscript>3</Subscript> in the condensed state

Refined thermodynamic functions (entropy, enthalpy increments, and reduced Gibbs energy) of scandium trifluoride ScF₃ in the crystalline and liquid states in the temperature range 5–2500 K are presented.     

Formation of active species in spark discharge and their possible use

The chemical effects of self-sustained spark discharge with an energy per pulse of 5.9 × 10⁻² J, a pulse repetition frequency of 10 Hz, and a spark-gap breakdown voltage of 6 kV have been studied. The discharge generated a UV photon flux of (2.5 ± 0.3) × 10¹⁵ cm⁻² s⁻¹ with an energy density of (2 ± 0.3) × 10⁻³ J cm⁻¹ s⁻¹ and the emission spectrum maximum at 220 nm. The action of the discharge on water samples leads to a decrease in pH and to buildup of oxidizing and reducing species. The formation of HO₂^· radicals with an initial yield of (1.2 ± 0.3) × 10⁻⁶ mol L⁻¹ s⁻¹ has been detected in the liquid. The initial yields of acid residues (increment in [H⁺]), oxidants, and reducing agents are (5.8 ± 1.6) × 10⁻⁷, (3.3 ± 1) × 10⁻⁶, and (4.2 ± 1) × 10⁻⁷ mol equiv L⁻¹s⁻¹, respectively. The formation of NO₃⁻ and NO₄⁺ ions, nitrosamines, and organic compounds has been established.     

Softening processes in single-crystal tungsten ribbons

Recovery processes in rolling-deformed (001)[110] tungsten single crystals having various degrees of purity are investigated. It is shown that the dislocation structure formed in the plastic deformation of tungsten single crystals is transformed in subsequent high-temperature anneals to a system of dislocation subboundaries; only polygonization, which preserves the single-crystal structure, takes place in samples heated to a temperature close to the melting point. The formation of subboundaries proceeds in two stages with subsequent transformation of the unstable structure to a configuration having an energy minimum. The decisive factor affecting the polygonization rate is the stacking fault energy; the presence of impurities also has a significant influence. Fiz. Tverd. Tela (St. Petersburg) 40, 498–502 (March 1998)