373 research outputs found
Supplementary material for the article: Milenković, M.; Shcherbakov, I. N.; Popov, L. D.; Levchenkov, S. I.; Borodkin, S. A.; Alexandrov, G. G. Synthesis, Characterization and Crystal Structures of Ni(II) and Cu(I) Complexes with the Condensation Product of 2-(Diphenylphosphino)Benzaldehyde and 1-Hydrazinophthalazine. Polyhedron 2017, 121, 278–284. https://doi.org/10.1016/j.poly.2016.10.020
Supplementary material for: [https://doi.org/10.1016/j.poly.2016.10.020]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2368]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3256
Scientific justification of the perforation methods for Famennian deposits in the southeast of the Perm Region based on geomechanical modelling
The article presents the results of analysing geological structure of the Famennian deposits (Devonian) in the Perm Region. Numerical modelling of the distribution of inhomogeneous stress field near the well was performed for the two considered types of perforation. With regard for the geometry of the forming perforation channels, numerical finite element models of near-wellbore zones were created considering slotted and cumulative perforation. It is ascertained that in the course of slotted perforation, conditions are created for a significant restoration of effective stresses and, as a result, restoration of reservoir rock permeability. Stress recovery area lies near the well within a radius equal to the length of the slots, and depends on the drawdown, with its increase, the area decreases. From the assessment of failure areas, it was found that in case of slotted perforation, the reservoir in near-wellbore zone remains stable, and failure zones can appear only at drawdowns of 10 MPa and more. The opposite situation was recorded for cumulative perforation; failure zones near the holes appear even at a drawdown of 2 MPa. In general, the analysis of results of numerical simulation of the stress state for two simulated types of perforation suggests that slotted perforation is more efficient than cumulative perforation. At the same time, the final conclusion could be drawn after determining the patterns of changes in permeability of the considered rocks under the influence of changing effective stresses and performing calculations of well flow rates after making the considered types of perforation channels
Supplementary material for the article: Milenković, M.; Shcherbakov, I. N.; Popov, L. D.; Levchenkov, S. I.; Borodkin, S. A.; Alexandrov, G. G. Synthesis, Characterization and Crystal Structures of Ni(II) and Cu(I) Complexes with the Condensation Product of 2-(Diphenylphosphino)Benzaldehyde and 1-Hydrazinophthalazine. Polyhedron 2017, 121, 278–284. https://doi.org/10.1016/j.poly.2016.10.020
Supplementary material for: [https://doi.org/10.1016/j.poly.2016.10.020]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2368]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3256
Potassium Ions are More Effective than Sodium Ions in Salt Induced Peptide Formation
Prebiotic peptide formation under aqueous conditions in the presence of metal ions is one of the plausible triggers of the emergence of life. The salt-induced peptide formation reaction has been suggested as being prebiotically relevant and was examined for the formation of peptides in NaCl solutions. In previous work we have argued that the first protocell could have emerged in KCl solution. Using HPLC-MS/MS analysis, we found that K(+) is more than an order of magnitude more effective in the L-glutamic acid oligomerization with 1,1'-carbonyldiimidazole in aqueous solutions than the same concentration of Na(+), which is consistent with the diffusion theory calculations. We anticipate that prebiotic peptides could have formed with K(+) as the driving force, not Na(+), as commonly believed
Unrepeatered 64QAM over SMF-28 using Raman amplification and digital backpropagation
Unrepeatered transmission over SMF-28 fibre is investigated using Raman based amplification. Experiments and simulations demonstrate a transmission up to 200 km (41 dB) span length using 28Gbaud 64 QAM modulation employing digital back propagation in DSP
Simulating Supersonic Turbulence in Magnetized Molecular Clouds
We present results of large-scale three-dimensional simulations of weakly
magnetized supersonic turbulence at grid resolutions up to 1024^3 cells. Our
numerical experiments are carried out with the Piecewise Parabolic Method on a
Local Stencil and assume an isothermal equation of state. The turbulence is
driven by a large-scale isotropic solenoidal force in a periodic computational
domain and fully develops in a few flow crossing times. We then evolve the flow
for a number of flow crossing times and analyze various statistical properties
of the saturated turbulent state. We show that the energy transfer rate in the
inertial range of scales is surprisingly close to a constant, indicating that
Kolmogorov's phenomenology for incompressible turbulence can be extended to
magnetized supersonic flows. We also discuss numerical dissipation effects and
convergence of different turbulence diagnostics as grid resolution refines from
256^3 to 1024^3 cells.Comment: 10 pages, 3 figures, to appear in the proceedings of the DOE/SciDAC
2009 conferenc
Catheter ablation or medical therapy to delay progression of atrial fibrillation : The randomized controlled atrial fibrillation progression trial (ATTEST)
Funding Information: This work was supported by Biosense Webster, Inc. Publisher Copyright: © 2020 The Author(s) 2020. Published by Oxford University Press on behalf of the European Society of Cardiology.Aims: Delay of progression from paroxysmal to persistent atrial fibrillation (AF) is an important measure of long-term success of AF treatment. However, published data on the impact of catheter ablation on AF progression are limited. This study evaluates whether radiofrequency (RF) catheter ablation delays the progression of AF compared with antiarrhythmic drug (AAD) treatment using current AF management guidelines. Methods: This prospective, randomized, controlled, two-arm, open-label trial was conducted at 29 hospitals and medical centres across 13 countries. Patients were randomized 1: 1 to RF ablation or AAD treatment. The primary endpoint was the rate of persistent AF/atrial tachycardia (AT) at 3 years. Results: After early study termination following slow enrolment, 255 (79%) of the planned 322 patients were enrolled (RF ablation, n = 128, AAD, n = 127); 36% of patients in the RF ablation group and 41% in the AAD group completed 3 years of follow-up. For the primary endpoint, the Kaplan-Meier estimate of the rate of persistent AF/AT at 3 years was significantly lower with RF ablation [2.4% (95% confidence interval (CI), 0.6-9.4%)] than with AAD therapy [17.5% (95% CI, 10.7-27.9%); one-sided P = 0.0009]. Patients ≥65 years were ∼4 times more likely to progress to persistent AF/AT than patients <65 years, suggesting RF ablation can delay disease progression [hazard ratio: 3.87 (95% CI, 0.88-17.00); P = 0.0727]. Primary adverse events were reported for eight patients in the RF ablation group. Conclusions: Radiofrequency ablation is superior to guideline-directed AAD therapy in delaying the progression from paroxysmal to persistent AF.publishersversionPeer reviewe
High-refractive index and mechanically cleavable non-van der Waals InGaS3
The growing families of two-dimensional crystals derived from naturally
occurring van der Waals materials offer an unprecedented platform to
investigate elusive physical phenomena and could be of use in a diverse range
of devices. Of particular interest are recently reported atomic sheets of
non-van der Waals materials, which could allow a better comprehension of the
nature of structural bonds and increase the functionality of prospective
heterostructures. Here, we study the optostructural properties of ultrathin
non-van der Waals InGaS3 sheets produced by standard mechanical cleavage. Our
ab initio calculation results suggest an emergence of authentically delicate
out-of-plane covalent bonds within its unit cell, and, as a consequence, an
artificial generation of layered structure within the material. Those yield to
singular layer isolation energies of around 50 meVA-2, which is comparable with
the conventional van der Waals material's monolayer isolation energies of 20 -
60 meVA-2. In addition, we provide a comprehensive analysis of the structural,
vibrational, and optical properties of the materials presenting that it is a
wide bandgap (2.73 eV) semiconductor with a high-refractive index (higher than
2.5) and negligible losses in the visible and infrared spectral ranges. It
makes it a perfect candidate for further establishment of visible-range
all-dielectric nanophotonics
Effect of Peierls transition in armchair carbon nanotube on dynamical behaviour of encapsulated fullerene
The changes of dynamical behaviour of a single fullerene molecule inside an
armchair carbon nanotube caused by the structural Peierls transition in the
nanotube are considered. The structures of the smallest C20 and Fe@C20
fullerenes are computed using the spin-polarized density functional theory.
Significant changes of the barriers for motion along the nanotube axis and
rotation of these fullerenes inside the (8,8) nanotube are found at the Peierls
transition. It is shown that the coefficients of translational and rotational
diffusions of these fullerenes inside the nanotube change by several orders of
magnitude. The possibility of inverse orientational melting, i.e. with a
decrease of temperature, for the systems under consideration is predicted.Comment: 9 pages, 6 figures, 1 tabl
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