二维渗流相关长度ξ(p)的幂估计(英文)

相关长度ξ(p)是渗流理论中最重要的一个量。本文对它给出了一个幂估计     

STABILITY NUMBER IN SUBCLASSES OF P5-FREE GRAPHS

Two new hereditary classes of P5-free graphs where the stability number can be found in polynomial time are proposed. They generalize several known results.     

Spectral-kinetic evidence of interaction of photochromic diarylethenes with silver nanoparticles

Spectral-kinetic investigations of the photochromism of some diarylethenes with sulfur-containing substituents in dimethylsulfoxide solutions with and without silver nanoparticles are performed. It is shown that silver nanoparticles chemically interact with diarylethene molecules, which is manifested in a change in the spectral and kinetic characteristics and photodegradation efficiency.     

Photoactivation of fluorescence of rhodamine dyes in the presence of haloalkanes

Organic halogen derivatives, viz., hexachloroethane, 2,2,2-trichloroethanol, 2,2,2-tribromoethanol, butyl trichloroacetate, 2,2,2-trichloroethyl methacrylate, can efficiently activate fluorescence of lactone forms of rhodamine dyes by UV irradiation through the UFS-1 light filter in both solutions and polymer poly(methyl methacrylate) films. This ability is also typical of the copolymer of methyl methacrylate and 2,2,2-trichloroethyl methacrylate, which is promising for the development of detecting media for archive optical data storage with fluorescent readout.     

Synthesis of new spiropyranes and study of the effect of the nature of substituents on their photochromism and complexation

A series of new hydrazones based on 3,3-dimethyl-7-hydroxy-8-formyl-[2H]-1-benzopyran-2,1-[2]-oxaindane] with the substituents of different nature in the hydrazone moiety was synthesized. A comparative study of photochromism and complexation of the synthesized spiropyrans with a number of metal cations was carried out. Spectral and kinetic differences in photochromism and complexation of these compounds were revealed.     

Photochromic fulgimide-containing silicones immobilized on the surface of polyarylate

Photochromic coatings immobilized on the surface of polyarylate films are prepared on the basis of fulgimides, oligosiloxanes, and oligosilazanes. The irradiation of coatings with UV light at a wavelength of @380 nm and visible light at a wavelength above 500 nm results in photoinduced reversible transitions between open and colored cyclic forms. Photochromic polymer films with the most acceptable characteristics are obtained from fulgimide-containing oligoaminosiloxane and oligovinyldimethylsilazane. It is found that the photosensitivity of these films is higher than that of similar films based on 1,2-dihetarylethenes.     

XPS study of SnTe(1 0 0) oxidation by molecular oxygen

The interaction between the (1 0 0) surface of SnTe single crystal and molecular oxygen was studied by means of X-ray photoelectron spectroscopy (XPS). Analysis of the obtained spectra shows that the mechanism of surface oxidation does not change in the range of oxygen exposure 10⁸-10¹³ L. During the oxidation an additional component shifted 1.1 eV towards higher binding energies appears in the Sn 3d spectra. The Te 3d_5/2 spectra fitting reveals two additional components with binding energies close to Te⁰ and Te⁺⁴. The dependence of the additional components fraction in both Sn 3d and Te 3d_5/2 spectra on the oxygen exposure is semi-logarithmic. On the base of the experimental data two possible mechanisms are proposed.     

Synthesis and photochromic properties of thiosemicarbazide and thiocarbazate derivatives of dithienylperfluorocyclopentene

A number of new thiosemicarbazide and thiocarbazate derivatives of dithienylperfluorocyclopentene have been synthesized. Spectral-kinetic study of photochemical transformations of these compounds was performed. All the compounds obtained exhibit photochromic properties. Dependencies of spectral characteristics of two thermally stable forms and kinetic properties of photocoloration and photodegradation processes from the nature of substituents affecting the conjugated bonds length in the molecules were found.