Effect of amorphization on the electronic and lattice specific heat of an Ni2B alloy

The specific heats of the Ni₂B amorphous system and of its crystal analog were studied in the temperature range 3–270 K. The data obtained permitted us to isolate the contribution due to atomic vibrations from the experimentally measured specific heat, determine the electronic density of states at the Fermi level and the temperature dependence of the characteristic Debye parameter Θ, and to calculate some average frequencies (moments) of the vibrational spectrum. The electronic density of states at the Fermi level increases under amorphization. An analysis of the temperature dependence of the lattice specific heat showed that amorphization brings about a substantial growth in the density of vibrational states at low frequencies, whereas the spectrum-averaged and rms frequencies change very little, which is in good agreement with neutron diffraction measurements.     

Thermostimulated luminescence and extended afterglow of NaI-Tl crystals

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 56, No. 2, pp. 259–263, February, 1992.     

Adsorption of Fire Retardant from Dilute Aqueous Solutions onto Viscose Fiber

The adsorption isotherms of the product of transesterification of dimethyl methylphosphonate (ZG-2), used as fire retardant, from dilute solutions on viscose fiber were determined experimentally at various temperatures. The parameters of pore structure of the fibrous sorbent were estimated using the general equation of the theory of volume filling of micropores.     

Non-covalent columnar cyclodextrin-based structures

Examples of the formation of ordered ensembles of α-, β-, and γ-cyclodextrins (CDs) molecules with a columnar packing of macrocycles are reported. These ensembles are formed by (1) the supramolecular dissociation of polymer inclusion complexes under the action of organic solvents that are selective with respect to a polymer guest and (2) the fixation of columnar CD aggregates self-organized in aqueous solutions at high temperatures upon the precipitation from water into organic solvents. Specific features of the organization of cyclodextrins in the thus-synthesized structures are studied by X-ray diffraction. Preliminarily oriented polymer inclusion complexes based on corresponding CDs are used as a model with the columnar arrangement of macrocycles.     

Synthesis and Structure of Tri-p-tolylantimony Ditosylate

Tri-p-tolylantimony reacts with p-toluenesulfonic acid in the presence of benzoyl peroxide (1 : 2 : 1 molar ratio) in ether to give tri-p-tolylantimony ditosylate in 91% yield. According to X-ray diffraction data, the central antimony atom has the trigonal bipyramidal coordination with the axial location of the tosyl groups. The Sb-O bond lengths are 2.07(2) and 2.17(2) Å; Sb-C bond lengths, 2.08(3), 2.13(3), and 2.13(3) Å; and OSbO bond angle, 175.6(7)°.     

Synthesis and Structure of Tetraphenylantimony Nitrate

The reaction of pentaphenylantimony with triphenylantimony dinitrate in toluene gives tetraphenylantimony nitrate in 99% yield. The X-ray diffraction data show that the antimony atom in the molecule of tetraphenylantimony nitrate has a distorted trigonal-bipyramidal coordination with axial location of the oxygen atom of the nitrate group. The Sb-O, Sb_{a x}, and Sb-C_{e q} bond lengths in two independent molecules of tetraphenylantimony nitrate are 2.498(3), 2.548(2); 2.134(3), 2.138(3); and 2.101(3)-2.112 Å.     

Periodical structure formation on a magnesium and aluminum surface under high power ion beam irradiation of nanosecond duration

The formation of periodical structures, and also, micro- and nanoparticles on a polycrystalline magnesium and aluminum surface under high power proton-carbon beam irradiation has been investigated. The spatial parameters of these structures and particle sizes have been determined. The possible mechanisms for periodical structure formation have been considered.     

Features of the surface morphology of brass and bronze upon irradiation with a high power ion beam

The change in the morphology and surface composition of copper alloys (brass LS 59-1, bronzes BrOS 10-10 and BrAJ 9-4) upon irradiation with a high power ion beam of nanosecond duration is studied. It is shown that craters are mainly formed at the location of lead or sulfur inclusions. The reverse deposition of zinc onto the surface of brass is found. Possible mechanisms of these phenomena are considered.     

Analysis of arsenic and mercury content in human remains of the 16th and 17th centuries from Moscow Kremlin necropolises by neutron activation analysis at the IREN facility and the IBR-2 reactor FLNP JINR

A neutron activation analysis (NAA) of three samples of human remains of the 16th and 17th centuries from the necropolises of the Moscow Kremlin has been carried out at FLNP JINR. The samples were irradiated at two facilities: the IREN source of resonance neutrons and the IBR-2 reactor. Spectra of the induced activity of the irradiated samples were measured by using the automatic measurement system developed at the Frank Laboratory of Neutron Physics (FLNP) of the Joint Institute for Nuclear Research (JINR). This system consists of a high-purity germanium detector with spectrometric electronics, a sample changer, and control software. Mass fraction of arsenic, mercury, and some other elements were calculated using two NAA methods—relative and absolute. The obtained values confirm the fact of acute mercury poisoning of Anastasia Romanovna, the first wife of Tsar Ivan Vasil’evich the Terrible, the first Russian Tsarina (died in 1560). High levels of mercury were detected in the bone remains of Tsarevich Ivan Ivanovich (died in 1581), the son of Tsar Ivan the Terrible, and Prince Mikhail Vasil’evich Skopin-Shuiskii (died in 1610). The results provide an opportunity to introduce into scientific circulation the exact values of mass fraction of mercury, arsenic, and other elements in the samples taken from the burials of the Russian historical figures of the second half of 16th–early 17th century.     

Metal phosphinohydrazone complexes

Russian Chemical Bulletin - The reaction of benzophenone hydrazone with chlorodiphenylphosphine in the presence of triethylamine affords the monophosphino derivative Ph2C=N-N(H)PPh2(1). The...