Vacuum effects in an asymptotically uniformly accelerated frame with a constant magnetic field

In the present article we solve the Dirac-Pauli and Klein Gordon equations in an asymptotically uniformly accelerated frame when a constant magnetic field is present. We compute, via the Bogoliubov coefficients, the density of scalar and spin 1/2 particles created. We discuss the role played by the magnetic field and the thermal character of the spectrum.Comment: 17 pages. RevTe

Experimental Method of Temperature and Strain Discrimination in Polymer Composite Material by Embedded Fiber-Optic Sensors Based on Femtosecond-Inscribed FBGs

Experimental method of temperature and strain discrimination with fiber Bragg gratings (FBGs) sensors embedded in carbon fiber-reinforced plastic is proposed. The method is based on two-fiber technique, when two FBGs inscribed in different fibers with different sensitivities to strain and/or temperature are placed close to each other and act as a single sensing element. The nonlinear polynomial approximation of Bragg wavelength shift as a function of temperature and strain is presented for this method. The FBGs were inscribed with femtosecond laser by point-by-point inscription technique through polymer cladding of the fiber. The comparison of linear and nonlinear approximation accuracies for array of embedded sensors is performed. It is shown that the use of nonlinear approximation gives 1.5–2 times better accuracy. The obtained accuracies of temperature and strain measurements are 2.6–3.8°C and 50–83 με in temperature and strain range of 30–120°C and 0–400 με, respectively

Tetra­methyl­ammonium dimethyl (phenyl­sulfonyl­amido)phosphate(1−)

The title compound, C4H12N+·C8H11NO5PS−, was obtained from tetra­methyl­ammonium hydroxide and dimeth­yl(phenyl­sulfon­yl)amido­phosphate. The tetra­methyl­ammonium cation has a slightly distorted tetra­hedral configuration and the N—C bond lengths lie in the range 1.457 (3)–1.492 (3) Å. In the crystal, no classical hydrogen bonds are observed between the cation and the anion

Reactivity of <i>C</i>‑Amino-1,2,4-triazoles toward Electrophiles: A Combined Computational and Experimental Study of Alkylation by Halogen Alkanes

A combination of computational and experimental methods was used to examine the structure–reactivity relationships in the reactions of <i>C</i>-amino-1<i>H</i>-1,2,4-triazoles with electrophiles. The global nucleophilicity of 3-amino- and 3,5-diamino-1<i>H</i>-1,2,4-triazoles was predicted to be higher than that of 5-amino-1<i>H</i>-1,2,4-triazoles. Fukui functions and molecular electrostatic potential indicate that reactions involving an amino group should occur more easily for the 3-amino- than for the 5-amino-1<i>H</i>-1,2,4-triazoles. Increasing electrophile hardness should increase the probability of attack at the N-4 atom of the triazole ring, whereas increasing softness should enhance the probability of attack at the N-2 atom and 3-NH₂ group. Calculated transition state energies of model S_N2 reactions and experimental studies showed that quaternization of 1-substituted 3-amino- and 3,5-diamino-1<i>H</i>-1,2,4-triazoles by many alkyl halides proceeds with low selectivity and can involve the N-2 and N-4 atoms as well as the 3-NH₂ group as reaction centers. A new method for the selective synthesis of 1,4-disubstituted 3-amino- and 3,5-diamino-1,2,4-triazoles based on quaternization of readily available 1-substituted 3-acetylamino-1,2,4-triazoles with subsequent removal of the acetyl protecting group by acid hydrolysis was developed