Growth and structure of ZnSnAs2 crystals

High-quality ZnSnAs₂ (I) single crystals have been grown. The unit cell parameters of compound I have been refined (a = b = 5.8360(1), c = 11.686(2) Å), and its crystal structure has been determined.     

Reactions of Aliphatic Diazo Compounds: IV. Reaction of Diphenyldiazomethane with Substituted Imides of Maleic and Itaconic Acids

Diphenyldiazomethane regioselectively adds to 2-R-substituted maleimides to yield 1-pyrazoline derivatives, 1-R-7-aryl-6,8-dioxo-4,4-diphenyl-2,3,7-triazabicyclo[3.3.0]oct-2-enes that on heating liberate nitrogen to afford substituted 3-azabicyclo[3.1.0]hexanes. To the N-arylsubstituted imides of itaconic acid the diphenyldiazomethane adds to furnish 5-aryl-4,6-dioxo-1,1-diphenyl-5-azaspiro[2.4]heptanes.     

Creatinine and creatininium cation in DMSO-d6 solution. Structure and restricted internal rotation of NH2 group

Investigation of 15N NMR spectra of isotopically enriched creatinine has unequivocally shown that in DMSO-d6 solution it exists as amino tautomer (2-amino-1-methylimidazoline-4-one), which in the presence of acid is protonated at N-3. Free energies of activation of the amino group rotation in creatinine and its cation have been determined to be 56 kJ/mol and 60 kJ/mol, respectively, at 298 K, by performing the simultaneous analysis of the lineshapes of -NH2 proton signals in the whole set of 1H NMR spectra recorded at various temperatures and magnetic fields. These results have been theoretically reproduced by the calculations of molecular structures and energies of creatinine and creatininium cation in their ground states and transition states of the amino group rotation, using DFT (B3LYP) method, involving the influence of the solvent.     

Thermal effects in a glass laminate in tension

The results of a calorimetric investigation of a glass-reinforced textolite in uniaxial tension are presented. The specimens were deformed on the interval of strain rates from 0.3 to 10.5 mm/min at test temperatures from –30 to 80°C. The thermal effects are shown to depend on strain rate and test temperature.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 4, pp. 599–604, July–August, 1971.     

Dependence of the structure of ring-shaped deposits resulting from evaporation of dispersion droplets on initial contact angle

Experiments have been performed on the formation of ding-shaped deposits upon the evaporation of dispersion droplets on different substrates accompanied by the coffee ring effect. The main attention has been focused on studying the structure of a formed deposit as depending on the initial contact angle of a droplet. It has been established that the deposit structure may vary from ring-shaped to disc-shaped with a decrease in the contact angle. For certain systems, as the initial contact angle is varied, the scenario of droplet evaporation may change and, in some cases, acquire a combined character. Before the onset of pinning, menisci of droplets that are evaporated on modified polymer substrates may initially move not only toward the droplet center, but also in the opposite direction.     

Uniform Strong Law of Large Numbers

Methodology and Computing in Applied Probability - We prove the strong law of large numbers for random signed measures. The result is uniform over a family of subsets under mild assumptions.     

Gas dynamics of a rocket plume in the upper atmosphere

We study the expansion of a rocket exhaust plume in the direction perpendicular to the rocket motion. We compare numerical calculations with a self-similar approximation for a strong cylindrically symmetric explosion and show that, if the rocket velocity V _∞ is high enough and exceeds the sum of the exhaust gas velocity V _e and the sound velocity V _s (V _∞ > V _e + V _s ), a gasdynamic hole may be formed for a short time around the rocket flight trajectory in the upper atmosphere, where the plume-gas concentration is less than the ambient-gas concentration at a given altitude. We calculate the density and temperature profiles of the transversal plume expansion.     

Thermodynamic study of characteristics of the converter with separated supply of hydrocarbon fuel for thermo-oxidative and steam reforming

Thermodynamic studies of the converter characteristics were performed to produce hydrogen-containing syngas from hydrocarbon fuel (kerosene) with its separated supply for thermo-oxidative and steam reforming. It is demonstrated that the optimal conditions of the converter performance correlate with the oxidant ratio of α > 0.5 at the heattransfer wall temperature of 1200 K. Hydrogen content in the final syngas reaches 60 % by volume, free carbon (soot) deposition in reforming products is excluded, and there is no need to apply walls water cooling in the converter.