Carbon Friction Pair in Total Hip Replacement

The article examines the advantages of a new pair of friction of the hip joint endoprosthesis made of pyrolytic carbon. The physico-mechanical and tribological characteristics of the material and their comparison with other materials used in the friction pair of hip joint endoprostheses are presented. Information is presented about the making of a material and its strength characteristics and the results of mathematical modeling of a friction pair. The results of a comparative research of the durability between a carbon pair of friction and a ceramic pair of friction

Extreme Sensitivity of Superconductivity to Stoichiometry in FeSe (Fe1+dSe)

The recently discovered iron arsenide superconductors, which display superconducting transition temperatures as high as 55 K, appear to share a number of general features with high-Tc cuprates, including proximity to a magnetically ordered state and robustness of the superconductivity in the presence of disorder. Here we show that superconductivity in Fe1+dSe, the parent compound of the superconducting arsenide family, is destroyed by very small changes in stoichiometry. Further, we show that non-superconducting Fe1+dSe is not magnetically ordered down to low temperatures. These results suggest that robust superconductivity and immediate instability against an ordered magnetic state should not be considered as intrinsic characteristics of iron-based superconducting systems, and that Fe1+dSe may present a unique opportunity for determining which materials characteristics are critical to the existence of superconductivity in high Tc iron arsenide superconductors and which are not.Comment: Updated to reflect final version and include journal referenc

Novel non-covalent supramolecular systems based on zinc(II) bis(dipyrromethenate)s with fullerenes

© 2018 Elsevier B.V. This paper presents the results of UV/vis, fluorescence, FT-IR, DOSY, and DFT study of a novel non-covalent supramolecular systems based on zinc(II) bis(dipyrromethenate)s ([Zn2L2]) with C60. It was found that zinc(II) bis(dipyrromethenate) forms stable supramolecular π-π-complexes ([Zn2L2(C60)4]) with C60. DFT calculations revealed stable complexation between [Zn2L2] and C60. The [Zn2L2(C60)4] LUMO energy levels are predominantly spread on the C60 unit and the HOMO energy levels are mainly spread on the [Zn2L2]. The photoinduced electron transfer testing by the substantial fluorescence quenching of the [Zn2L2] by non-covalent bonded C60 gives the positive result that shows prospects of the studying [Zn2L2(C60)4] as the active layers in solar energy conversion devices

Enzymatic properties of thiol-dependent serine proteinase of Bacillus intermedius 3-19

Effects of a thiol-dependent serine proteinase of Bacillus intermedius on peptide substrates and insulin B-chain were studied. The enzyme preferably splits peptide bonds formed by carboxyl groups of hydrophobic amino acids. Ca2+ increases the thermal stability of the proteinase significantly. The kinetic characteristics of hydrolysis of Z-Ala-Ala-Leu-pNA by this enzyme was determined as Km = 1.25 mM and kcat = 0.15 sec-1. The enzyme has high stability to DMFA and isopropanol, and is able to catalyze peptide bond synthesis

IMPLEMENTATION OF DIGITAL METHODS TO ANALYSE EDDY-CURRENT SIGNALS BASED ON THE E14-440 MODULE

Using digital methods to analyze eddy-current signals was proposed. Quadrature ampli-tude demodulation and fast Fourier transformation was used. Both methods can be used in-stead of analog demodulator. Such approach increases the range of signal forms and unifies hardware.Работа выполнена в рамках государственного задания МИНОБРНАУКИ России (тема «Диагностика», № АААА-А18-118020690196-3)

Detection of Gamma-rays around 1TeV from RX J0852.0-4622 by CANGAROO-II

We have detected gamma-ray emission at the 6sigma level at energies greater than 500GeV from the supernova remnant RX J0852.0-4622 (G266.2-1.2) using the CANGAROO-II Imaging Atmospheric Cherenkov Telescope (IACT). The flux was 0.12 times of that of Crab at 1TeV. The signal centroid is consistent with the peak of the X-ray emission in the north-west rim of the remnant.Comment: 12pages, 4figures, to be published in ApJ

Search for VHE gamma rays from SS433/W50 with the CANGAROO-II telescope

SS433, located at the center of the supernova remnant W50, is a close proximity binary system consisting of a compact star and a normal star. Jets of material are directed outwards from the vicinity of the compact star symmetrically to the east and west. Non-thermal hard X-ray emission is detected from lobes lying on both sides. Shock accelerated electrons are expected to generate sub-TeV gamma rays through the inverse-Compton process in the lobes. Observations of the western X-ray lobe region of SS433/W50 system have been performed to detect sub-TeV gamma-rays using the 10m CANGAROO-II telescope in August and September, 2001, and July and September, 2002. The total observation times are 85.2 hours for ON source, and 80.8 hours for OFF source data. No significant excess of sub-TeV gamma rays has been found at 3 regions of the western X-ray lobe of SS433/W50 system. We have derived 99% confidence level upper limits to the fluxes of gamma rays and have set constraints on the strengths of the magnetic fields assuming the synchrotron/inverse-Compton model for the wide energy range of photon spectrum from radio to TeV. The derived lower limits are 4.3 microgauss for the center of the brightest X-ray emission region and 6.3 microgauss for the far end from SS433 in the western X-ray lobe. In addition, we suggest that the spot-like X-ray emission may provide a major contribution to the hardest X-ray spectrum in the lobe.Comment: 7 pages, 8 figures, to be published in Astroparticle Physic

Application of 57Fe Mössbauer spectroscopy as a tool for mining exploration of bornite (Cu5FeS4) copper ore

Nuclear resonance methods, including Mössbauer spectroscopy, are considered as unique techniques suitable for remote on-line mineralogical analysis. The employment of these methods provides potentially significant commercial benefits for mining industry. As applied to copper sulfide ores, Mössbauer spectroscopy method is suitable for the analysis noted. Bornite (formally Cu5FeS4) is a significant part of copper ore and identification of its properties is important for economic exploitation of commercial copper ore deposits. A series of natural bornite samples was studied by 57Fe Mössbauer spectroscopy. Two aspects were considered: reexamination of 57Fe Mössbauer properties of natural bornite samples and their stability irrespective of origin and potential use of miniaturized Mössbauer spectrometers MIMOS II for in-situ bornite identification. The results obtained show a number of potential benefits of introducing the available portative Mössbauer equipment into the mining industry for express mineralogical analysis. In addition, results of some preliminary 63,65Cu nuclear quadrupole resonance (NQR) studies of bornite are reported and their merits with Mössbauer techniques for bornite detection discussed

Detection of Sub-TeV Gamma-Rays from the Galactic Center Direction by CANGAROO-II

We have detected sub-TeV gamma-ray emission from the direction of the Galactic Center (GC) using the CANGAROO-II Imaging Atmospheric Cherenkov Telescope (IACT). We detected a statistically signicant excess at energies greater than 250GeV. The flux was one order of magnitude lower than that of Crab at 1 TeV with a soft spectrum E^{-4.6+-0.5}. The signal centroid is consistent with the GC direction and the observed prole is consistent with a point-like source. Our data suggests that the GeV source 3EG J1746-2851 is identical with this TeV source and we study the combined spectra to determine the possible origin of the gamma-ray emission. We also obtain an upper limit on the cold dark-matter density in the Galactic halo.Comment: 13 pages, 3 figures, aastex.cls, accepted by ApJ Letter