Investigation of conversion of polyamido acid into polyimide by thermovolumetric analysis

Thermovolumetric analysis has shown that conversion of solution of polyamido acid into polyimide occurs in three stages: removal of solvent, dehydrocyclization and, in the case of DMFA as solvent, removal of products of its decomposition. When dimethyl-sulphoxide and methyl pyrrolidone were used as solvents, the third stage was absent.     

Evaluation of optical loss minima in thallium halide crystals

Fundamental optical losses in the highly transparent region for thallium halide KRS-6 and KRS-5 crystals were evaluated. The projected loss minima are 12 × 10^--⁴ dB/ km at 7.9 μm for KRS-6 and 7 × 10^--⁴ dB/km at 12.9 μm for KRS-5 crystals. The material dispersion becomes zero near 5.05 μm for KRS-6 and near 6.62 μm for KRS-5 crystals.     

Synthesis and Antibacterial Activity of New N9-Substituted Acridine-9-amines

Russian Journal of General Chemistry - A method for the synthesis of N9-substituted acridine-9-amines by reacting 9-chloroacridines with 2-(2-methyl-5- nitro-1H-imidazol-1-yl)ethanamine was...     

Results of Quantitative Analysis of High-Speed Shadowgraphy of Shock Tube Flows Using Machine Vision and Machine Learning

Doklady Physics - This paper presents the results of studies on unsteady gas-dynamic flows up to six milliseconds in duration in the shock tube channel. The results were acquired by continuous...     

Volatile Heteroligand Complexes of Copper(II): New Precursors for Chemical Vapor Deposition of Copper Films

Two heteroligand ketoiminate–diketonate complexes of copper(II), CuL(hfa) (1), L = pentane-2-imino-4-onato, CH₃COCHCNHCH ₃ ^– , and CuL′(hfa) (2), L′ = 2,2,6,6-tetramethyl-3-iminoheptane-5-onato, C(CH₃)₃COCHCNHC(CH)^–, were studied as precursors for chemical vapor deposition of copper films. The flow method was employed to measure the temperature dependences of a saturated vapor pressure of these compounds, the thermodynamic parameters of evaporation–sublimation were calculated, and the volatilities of these compounds and thermal behaviors in the condensed and gaseous phases were compared. The copper films were compared, and it was shown that comparatively high growth rates are reached when (2) is used to obtain copper films in hydrogen.     

Crystal structure and vapor pressure of a copper(II) complex with 2,2,6,6-tetramethyl-4-fluoroheptane-3,5-dione

Synthesis and single crystal X-ray diffraction study were carried out for copper(II) 2,2,6,6-tetramethyl-4-fluoroheptane-3,5-dionate (Bruker AXS P4 automated diffractometer, MoK _α radiation). Crystal data for C₂₂H₃₆CuF₂O₄: a = 5.9165(4) Å, b = 10.2787(7) Å, c = 10.5223(8) Å, α = 81.383(3)°, β = 76.106(3)°, γ = 83.778(3)°, space group P $\bar 1$ , V = 612.42(7) ų, Z = 1, d _x = 1.264 g/cm³. The structure is molecular; the copper atom has a square plane coordination formed by the oxygen atoms of two β-diketonate ligands; the average Cu-O distance is 1.895 Å, ∠O-Cu-O 92.5°. Only van der Waals interactions are realized between the molecules in the structure. The temperature dependences of the saturated vapor pressure were studied by the mass transfer technique, and the standard thermodynamic parameters of sublimation were derived for the complex, ΔH _subl ⁰ = 115.6 ± 1.1 kJ/mol, ΔS _subl ⁰ = 204.9 ± 2.5 J/mol·K.