Dynamics,Phase Constraints,and Linear Programming

Computational Mathematics and Mathematical Physics - A new approach to solving terminal control problems with phase constraints, using sufficient optimality conditions, is considered. The approach...     

Single-crystal structure of vanadium-doped La2Mo2O9

A high-precision X-ray diffraction study of single crystals of two compositions—La₂Mo_1.78V_0.22O_8.89 and La₂Mo_1.64V_0.36O_8.82—was performed. In the vanadium-doped compounds, as in the structure of the metastable β_ms phase of pure La₂Mo₂O₉, the La and Mo atoms and one of the three oxygen atoms are displaced from the threefold axis, on which they are located in the high-temperature β phase. The structure contains two partially occupied oxygen sites. It was shown that molybdenum atoms are partially replaced by vanadium atoms, which are not involved in the disordering, are located on the threefold axis, and are shifted toward one of the oxygen atoms. This is consistent with the temperature-induced changes in the structure of La₂Mo₂O₉ and the changes in the properties of these crystals caused by the introduction of vanadium atoms into the structure.     

Solvability of a boundary value problem for operator-differential equations of mixed type

We study boundary value problems for operator-differential equations of mixed type, prove existence of generalized solutions, and establish their smoothness in weighted Sobolev spaces. The results are applied to odd order forward-backward equations.     

Haag’s theorem in noncommutative quantum field theory

Haag’s theorem was extended to the general case of noncommutative quantum field theory when time does not commute with spatial variables. It was proven that if S matrix is equal to unity in one of two theories related by unitary transformation, then the corresponding one in the other theory is equal to unity as well. In fact, this result is valid in any SO(1, 1)-invariant quantum field theory, an important example of which is noncommutative quantum field theory.     

New DNA-sensor based on thiacalix[4]arene-modified polydiacetylene particles

Russian Chemical Bulletin - New p-tert-butyl thiacalix[4]arene derivative in the 1,3-alternate stereoisomeric form containing two diethylenetriamine groups and pentacosa-10,12-diynoic moieties on...     

Heat-Resistant Epoxy Polymers of Anhydride Curing

The interaction of UP-643 epoxy-novolac resin with isomethyltetrahydrophthalic anhydride in the presence of the catalysts (azo-compounds of different structure) is studied. Latency of the catalysts is found. The possibility is shown of creating epoxy binders with a long lifetime (10–40 days) at room temperatures, cured at increased temperature up to heat-resistant polymers.