264 research outputs found
Technological Schemes for Preparation and Deep Beneficiation of Technogenic Waste Containing Fine Slimes Environmental Component
This article evaluates a new procedure for choosing special methods of disintegration for technogenic rock materials with fines and slimes. The article describe different examples of beneficiation technology for chromium-containing slime tails of the Donskoy beneficiation plant (Republic of Kazakhstan), hematite tails of Magnitogorskiy Metallurgical Plant, and tin waste with fines particles.
Keywords: fine slimes, environmental component, technological schemes, Preparation technogenic wast
Homogeneous nucleation of dislocations as bifurcations in a periodized discrete elasticity model
A novel analysis of homogeneous nucleation of dislocations in sheared
two-dimensional crystals described by periodized discrete elasticity models is
presented. When the crystal is sheared beyond a critical strain , the
strained dislocation-free state becomes unstable via a subcritical pitchfork
bifurcation. Selecting a fixed final applied strain , different
simultaneously stable stationary configurations containing two or four edge
dislocations may be reached by setting during different time
intervals . At a characteristic time after , one or two dipoles
are nucleated, split, and the resulting two edge dislocations move in opposite
directions to the sample boundary. Numerical continuation shows how
configurations with different numbers of edge dislocation pairs emerge as
bifurcations from the dislocation-free state.Comment: 6 pages, 4 figures, to appear in Europhys. Let
VALSARTAN IN EVERYDAY CLINICAL PRACTICE IN RUSSIA: ANTIHYPERTENSIVE EFFICACY AND INFLUENCE ON SEXUAL FUNCTION IN PATIENTS WITH ARTERIAL HYPERTENSION
Aim. To study antihypertensive efficacy and safety of valsartan-based therapy (Diovan, Novartis Pharma) as well as patient’s compliance and influence of treatment on several aspects of sexual function.Material and methods. 114 doctors from 81 medical institutions of Russia participated in this prospective multicenter observation study. 650 hypertensive patients (average age 53,9±0,4 y.o.) were enrolled. The evaluation of therapy efficacy was based on analysis of systolic (SBP) and diastolic (DBP) blood pressure (BP) changes. Safety and compliance of treatment was also analyzed. The evaluation of sexual function was performed with 5 universal questions selected form the International Index of Erectile Function. These questions could be asked in both men and women. The valsartan dose was 80-320 mg OD. A combination of the valsartan with hydrochlorothiazide (12,5-25 mg/d), amlodipine (5-10 mg/d) or any other antihypertensive was allowed.Results. Significant similar decrease of SBP and DBP was observed in smoking and non-smoking patients (37,5/18,5 and 37,6/15,9 mm Hg respectively, р<0,01 vs baseline). 312 patients (56,9% men, 43,1% women) completed sexual function survey. After 12 weeks of treatment the number of patients without sexual activity and with 1-2 successful sexual attempts in the last 4 weeks significantly decreased from 22 to 16% and from 44 to 30% respectively (р<0,05). Significant increase in the number of patients with 5-6 and 7-10 successful sexual attempts was observed (from 7 to 20% and from 0 to 7% respectively, р<0,05). The treatment resulted in significant increase in the number of patients, who characterized their sexual life satisfaction as “very satisfied” (from 11 to 25%, р<0,01).Conclusion. During the course of effective antihypertensive treatment there was a significant increase in sexual function and general satisfaction with sexual life in patients with arterial hypertension, which could have favorable long-term consequences in increased compliance to the antihypertensive therapy
Spectroscopic investigations of dispersion-shifted fiber with thin active Bi-doped ring and high nonlinear refractive index
A germanium-doped silica-core fiber with an active region in the form of a thin ring of silica doped with bismuth ions was fabricated. Bismuth doping in the ring surrounding the core allows to stabilize bismuth in silica glass, and it does not impose any restrictions on the composition of the core. The bismuth concentration in the ring is less than 0.2 wt.%. The GeO2 concentration in the core is more than 15 mol.%. A high germanium concentration in the core allows to shift the zero dispersion wavelength to 1860 nm and to obtain a high nonlinear refractive index (n2 more than 3,2*10-20 m2/W). Spectroscopic investigations were carried out in the visible and near infrared (800-1700 nm) spectral range. Despite the small concentration of bismuth, we observed the absorption and luminescence characteristic bands, confirming the presence of bismuth active centers in silica glass. Upon pumping at 1350 nm the on/off gain spectrum was measured on a 20-m fiber. The gain was observed throughout investigated range of 1430-1530 nm. The maximal gain of ~9.5 dB was obtained near 1430 nm. The results of the spectroscopic investigations of the fiber with a thin active Bi-doped ring showed prospects of the creation and application of such fiber type for laser and nonlinear optics
AGE AND GEODYNAMIC SETTINGS OF MIASKITE-PEGMATITES, CARBONATITES, AND Nb-Zr MINERALIZATION OF THE ILMENO-VISHNEVOGORSKY ALKALINE COMPLEX, SOUTH URAL (U-Pb AND Rb-Sr ISOTOPE DATA)
The Ilmeno-Vishnevogorsky miaskite-phenite-carbonatite complex (IVС), located in the Urals folded region, is a representative of "linear type" carbonatite complexes, with which Nb-Zr deposits are associated. The ore potential of linear carbonatite complexes, the time and duration of ore-forming processes, and the geodynamic setting remain the subject of discussion. In order to estimate the age and duration of ore formation processes in the IVC, the U-Pb dating of zircon (LA-ICP-MS) from miaskite-pegmatites, as well as Rb-Sr dating of ore-bearing (pyrochlore-bearing) varieties of miaskite-pegmatites and carbonatites (ID-TIMS) were carried out. The U-Pb dating of zircon from the IVC miaskite-pegmatites showed the Permian age (280±8 Ma, P1 – age of the main zircon generation). The Rb-Sr-mineral isochron of miaskite-pegmatite showed a close age of 274±5 Ma (P1), confirming the results of U-Pb-dating of miaskite-pegmatites. The Rb-Sr dating of pyrochlore carbonatite varieties (sovites II) showed an age of 250±3 Ma (T1). The results of Rb-Sr- and U-Pb dating indicate that the processes of pegmatite- and carbonatite formation and the associated Zr-Nb ore formation in IVC occurred at the late collisional and postcollisional stage of development of the Ural folded region. Based on the data obtained, the geodynamic model for the IVC formation was proposed
Manifestation of exciton Bose condensation in induced two-phonon emission and Raman scattering
The unusual two-photon emission by Bose-condensed excitons caused by
simultaneous recombination of two excitons with opposite momenta leaving the
occupation numbers of excitonic states with momenta unchanged
(below coherent two-exciton recombination) is investigated. Raman scattering
accompanied by the analogous two-exciton recombination (or creation) is also
analyzed. The excess momentum equal to the change of the electromagnetic field
momentum in these processes can be transferred to phonons or impurities. The
processes under consideration take place if there is Bose condensation in the
interacting exciton system, and, therefore, can be used as a new method to
reveal exciton Bose condensation. If the frequency of the incident light
( is the frequency corresponding to the recombination
of an exciton with p=0), the coherent two-exciton recombination with the excess
momentum elastically transferred to impurities leads to the appearance of the
spectral line corresponding to the induced two-photon
emission. In this case the anti-Stokes line on frequency also
appears in the Raman spectrum. If , there are both Stokes and
anti-Stokes lines on frequencies in the Raman spectrum. The
induced two-photon emission is impossible in this case. The spectral lines
mentioned above have phonon replicas on frequencies corresponding to the transmission of the excess
momentum (partially or as a whole) to optical phonons of frequency
( is an integer number).Comment: 21 pages, 2 Postscript figures. Submitted to Phys. Rev. B (1998
Null Energy Condition Violation and Classical Stability in the Bianchi I Metric
The stability of isotropic cosmological solutions in the Bianchi I model is
considered. We prove that the stability of isotropic solutions in the Bianchi I
metric for a positive Hubble parameter follows from their stability in the
Friedmann-Robertson-Walker metric. This result is applied to models inspired by
string field theory, which violate the null energy condition. Examples of
stable isotropic solutions are presented. We also consider the k-essence model
and analyse the stability of solutions of the form .Comment: 27 pages, references added, accepted for publication in Phys. Rev.
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