The spaces of meromorphic Prym differentials on a finite Riemann surface

In the previous articles the second author started constructing a general theory of multiplicative functions and Prym differentials on a compact Riemann surface for arbitrary characters. Function theory on compact Riemann surfaces differs substantially from that on finite Riemann surfaces. In this article we start constructing a general function theory on variable finite Riemann surfaces for multiplicative meromorphic functions and differentials. We construct the forms of all elementary Prym differentials for arbitrary characters and find the dimensions of, and also construct explicit bases for, two important quotient spaces of Prym differentials. This yields the dimension of and a basis for the first holomorphic de Rham cohomology group of Prym differentials for arbitrary characters.     

Reactions of Elemental Phosphorus and Phosphines with Electrophiles in Superbasic Systems: XIII. Phosphorylation of Phenylacetylene with Active Modifications of Elemental Phosphorus

Phosphorylation of phenylacetylene with white or activated red phosphorus (prepared from white phosphorus under the action of ionizing radiation) occurs in KOH-DMSO or KOH-HMPA systems with heat evolution and stereoselective formation of Z isomers of tristyrylphosphine and -phosphine oxide in yields of 48-49% and 10-15%, respectively. Under the comparable conditions the commercial red phosphorus is considerably less reactive toward phenylacetylene: The total yield of the above-mentioned products is 5%.     

Synthesis of 4,<Emphasis Type="Italic">N</Emphasis>-diaryl-2-methyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxamides

Cyclohexane-1,3-dione reacted with substituted benzaldehydes and N-arylacetoacetamides in the presence of ammonium acetate under solvent-free conditions (150–160°C, 10–20 min) to give the corresponding 4,N-diaryl-2-methyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxamides. The product structure was determined by IR and ¹H NMR spectroscopy and mass spectrometry.     

Gap solitons in an extended anti-directional coupler

A nonlinear solitary wave in an inhomogeneous medium formed by two tunnel-coupled waveguides is considered. One of the waveguides is manufactured from an ordinary dielectric, while the second has negative refraction. The results from numerical simulations demonstrate the high stability of gap solitons with respect to collisions. It is discovered that for low relative velocities of two colliding solitons, a longlived coupled state of these solitons can be formed.     

Polyfluoroalkyl Phosphates Bearing Propargyl Substituents

Russian Journal of General Chemistry - Polyfluoroalkyl dichlorophosphates react easily with propargyl alcohol under mild conditions (22–62°С, 3 h, pyridine-toluene) to form...     

Thermogravimetry as a Method for Investigating the Thermal Stability of Polymer Composites

Thermogravimetry was used to investigate the effects of different inorganic functional fillers on the heat resistance of polymer matrices. The kinetic parameters of thermal oxidative degradation were shown to depend on the polymer, the chemical composition of the filler surface, the filler concentration, and the processing method, which determines the distribution of filler particles in the polymer matrix. Magnetic fillers (carbonyl iron, and hexaferrites of different structural types) were shown to be chemically active fillers, increasing the heat resistance of siliconorganic polymers. Their stabilizing effect is due to blocking of the end silanol groups and macroradicals by the surface of the filler and non-chain inhibition of thermal oxidative degradation. In the case of fiber-forming polymers (UHMWPE, PVOH and PAN), most magnetic fillers are chemically inert, but at concentrations of 30–50 vol% they increase the heat resistance of the composite. Addition of carbon black increased the heat resistance of the thermoplastic matrix. The dependence of the thermal degradation onset temperature on the kaolin concentration in the polyolefin matrix exhibited a maximum. Analysis of the experimental results demonstrated the operating temperature ranges for different composites, and their maximum operating temperature. This revised version was published online in July 2006 with corrections to the Cover Date.     

Atomic Force Microscopy Examination of Elementary Processes in Metalorganic Compound Hydride Epitaxy of GaAs-Based Nanoheterostructures

Technical Physics - Elementary processes involved in low-pressure metalorganic compound hydride epitaxial growth of (Al, Ga, In)As heterostructures on misoriented GaAs(001) substrates have been...