Specific Features of Crystal Structure and Surface Topography of Copper Electrolytic Foils for Printed-Circuit Boards

Specific features of formation of a pyramidal surface relief and [110] texture in raw electrolytic copper foil obtained in industrial electrolyzers with rotating titanium drum cathode at varied current density and electrolyte composition and temperature were studied. The effect of how the drum cathode is treated prior to deposition on the crystal structure and surface topography of the raw foil was analyzed.     

Extension of congruences on semirings of continuous functions

The lattices of congruences of semirings and semifields of continuous nonnegative functions over an arbitrary topological space are studied. It is proved that congruences of the semifield of continuous positive functions can be extended to congruences of the semiring of continuous nonnegative functions.     

Catalytic asymmetric C-H insertions of rhodium(II) azavinyl carbenes

A highly efficient enantioselective C-H insertion of azavinyl carbenes into unactivated alkanes has been developed. These transition metal carbenes are directly generated from readily available and stable 1-sulfonyl-1,2,3-triazoles in the presence of chiral Rh(II) carboxylates and are used for C-H functionalization of alkanes to access a variety of β-chiral sulfonamides.     

Regiodivergent metal-catalyzed rearrangement of 3-iminocyclopropenes into N-fused heterocycles

A highly efficient regiodivergent method for the synthesis of N-fused heterocycles via transition-metal-catalyzed rearrangement of 3-iminocyclopropenes has been developed.     

The principal kernels of semifields of continuous positive functions

This work is devoted to the study of kernel lattices of semifields of continuous positive functions defined on some topological space. It is established that they are lattices with a pseudo-complement. New characterizations of the following properties of topological spaces are obtained in terms of kernels, predominantly principal kernels, and semifields of continuous functions: to be an F-space, to be a P-space, basic and extremal disconnectedness, pseudo-compactness, and finiteness.     

Effect of a Travelling Magnetic Field on the Parameters of Tellurium-Doped Gallium Arsenide Single Crystals Grown by the Czochralski Method

Crystallography Reports - The effect of a traveling magnetic field on the parameters of Te-doped GaAs single crystals in the carrier density range of 5 × 1017–2 ×...     

Cross-section measurements for the 58,60,61Ni(n, α)55,57,58Fe reactions at 8.50, 9.50 and 10.50 MeV neutron energies

Cross sections of the ^58,60,61Ni(n, α)^55,57,58Fe reactions were measured at 8.50, 9.50 and 10.50 MeV neutron energies based on the HI-13 tandem accelerator of China Institute of Atomic Energy (CIAE) with enriched ⁵⁸Ni, ⁶⁰Ni, and ⁶¹Ni foil samples with backings. A twin gridded ionization chamber (GIC) was used as the charged particle detector, and an EJ-309 liquid scintillator was used to obtain the neutron energy spectra. The relative and absolute neutron fluxes were determined via three highly enriched ²³⁸U₃O₈ samples inside the GIC. The uncertainty of the present data of the ⁵⁸Ni(n, α)⁵⁵Fe reaction is smaller than most existing measurements. The present data of ⁶⁰Ni(n, α)⁵⁷Fe and ⁶¹Ni(n, α)⁵⁸Fe reactions are the first measurement results above 8 MeV. The present experimental data could be reasonably reproduced by calculations with TALYS-1.9 by adjusting several default values of theoretical model parameters.     

Synthesis of 2-(3,3-Dicyano-2-propenylidene)-4,4,5,5-tetramethyldioxolane and Its Reactions with Hydrazine and Primary Amines

Reactions of 2-(-ethoxyvinyl)-4,4,5,5-tetramethyl-4,5-dihydro-1,3-dioxol-1-ium salts with cyanomethylene compounds gave the corresponding 2-(2-propenylidene)-1,3-dioxolane derivatives which reacted with hydrazine and primary amines to afford, respectively, 3-(2-hydroxy-1,1,2-trimethylpropoxy)pyrazole and 1-substituted 6-amino-5-cyanopyridin-2(1H)-ones.     

Direct palladium-catalyzed arylation of cyclopropenes

The first examples of direct palladium-catalyzed arylation and heteroarylation of cyclopropenes have been demonstrated. This method allows for efficient synthesis of various tetrasubstituted cyclopropenes, incuding nonracemic cyclopropenes, which are not available via known asymmetric cyclopropenation methods. Mechanistic studies strongly suggest an electrophilic path for this Heck-type transformation.