Synthesis and luminescent properties of functionalized polynorbornenes with boron-containing fragments in side chains

Russian Chemical Bulletin - New norbornene monomer, viz., 5-[(bicyclo[2.2.1]hept-5-en-2-ylmethoxy)methyl]-8-[(dimesitylboryl)oxy]quinoline (1), was synthesized. The copolymers based on monomer 1...     

Probe Raman spectroscopy of sodium uranyl-acetate microcrystals

The technique for recording Raman spectra in uranium compounds using a probe minispectrometer with a multielement radiation detector has been developed. A selective filter, which reflects exciting laser radiation and transmits Raman signals, has been used to suppress the exciting radiation. It is shown that the technique developed makes it possible to record Raman spectra from a small amount (~10^–5 g) of sodium uranyl-acetate polycrystals in a wide spectral range for several seconds.     

How to measure the accuracy of the subexponential approximation for the stationary single server queue

We discuss the problem of establishing an upper bound for the distribution tail of the stationary waiting time D in the GI/GI/1 FCFS queue.     

Surface characteristics of V-Ga alloys after irradiation by Ar<Superscript>+</Superscript> and N<Superscript>+</Superscript> ions

V-5Ga-6Cr and V-5Ga-0.05Ce vanadium alloys irradiated by Ar⁺ and N⁺ ions with energies of 20 keV have been investigated. Irradiation by Ar⁺ and N⁺ ions leads to strengthening of the surface layers of samples. Their thicknesses exceed the projectile ranges of these ions (16.4 and 32.8 nm, respectively) in vanadium by more than two orders of magnitude. The experimentally determined penetration depth of argon ions is less that 70 nm. The sample side irradiated by Ar⁺ ions has a predominant orientation of crystallites in the (100) and (211) planes, while the unirradiated sample has a (110) surface. The lattice parameter of the irradiated sample does not differ from that of the initial sample. Possible mechanisms by which modified deep layers are formed during ion bombardment are discussed.     

Ion implantation into metals simultaneously irradiated by electrons

It has been revealed that concomitant irradiation by 1-keV electrons changes the depth distributions of the N and C atoms implanted with the energies of 10 and 30 keV in nickel and stainless steel samples. Instead of a single peak, the distribution has two peaks; one peak is closer to the surface and the other is located deeper than that in the absence of electron irradiation. The electron radiation effect is attributed to the formation of a band above the Fermi level in the atomic system whereto the metal electrons are transferred due to the electron bombardment excitation. The electrons in this band have a quite long lifetime and increase the mobility of impurity atoms.     

Multielectron approach to the electronic structure and mechanisms of superconductivity in high-Tc cuprates

A review of recent results for the doping dependence of the Fermi surface and mechanism of pairing in LaSrCuO obtained within the LDA+GTB multielectron approach is given. Both magnetic and phonon contributions to the d_x²-y²-gap are considered.     

Study of low-frequency polarized spectra of a mixed para-dibromobenzene-para-bromochlorobenzene crystal

Polarization studies of low-frequency Raman spectra of a mixed (1: 1) para-dibromobenzene-para-bromochlorobenzene crystal are performed. The spectrum of the mixed crystal is similar to the spectra of its components and also exhibits a number of additional low-intensity lines. The experimental results are interpreted using calculations of mixed crystals by the methods of atom-atom potentials and of Dean. It is found that the experimental results better agree with calculations when the disordered distribution of para-bromochlorobenzene molecules over para-positions is taken into account     

Oxidation of copper nanopowders on heating in air

The morphology and structure of copper nanopowders produced by electrical explosion of conductors are considered. The regularities of nanopowder oxidation in air were studied during linear and isothermal heating. The characteristics of initial powders in relation to the kinetic oxidation parameters were determined and the dependence of phase composition of the products of nanopowder oxidation on the heating conditions and dispersity of initial powders was found.     

Metal complexes of 2-hetarylindandiones-1,3

The chelate and molecular complexes of 2-(2-benzazolyl, perimidyl)-indandiones-1,3 were synthesized for the first time. The structures of the ligands (tautomeric forms) and complex compounds were determined from the X-ray diffraction, ¹H, ¹³C NMR, and IR data and the quantum-chemical calculations (RHF SCF in 6-31 G** basis).