Stankiewicz J.,University of Zaragoza |
Karpenkov D.,Tver State University |
Skokov K.P.,Tver State University
Physical Review B - Condensed Matter and Materials Physics | Year: 2011
We have measured the resistivity and Hall effect of R 2Fe 17 (R=Y, Tb, and Gd) single crystals in the temperature T range 4
Sharov G.S.,Tver State University |
Vorontsova E.G.,Tver State University
Journal of Cosmology and Astroparticle Physics | Year: 2014
For different gravitational models we consider limitations on their parameters coming from recent observational data for type Ia supernovae, baryon acoustic oscillations, and from 34 data points for the Hubble parameter H(z) depending on redshift. We calculate parameters of 3 models describing accelerated expansion of the universe: the ΛCDM model, the model with generalized Chaplygin gas (GCG) and the multidimensional model of I. Pahwa, D. Choudhury and T.R. Seshadri. In particular, for the ΛCDM model 1σ estimates of parameters are: H0=70.262±0.319 km -1Mp -1, Ωm=0.276-0.008+0.009, ΩΛ=0.769±0.029, Ωk=-0.045±0.032. The GCG model under restriction 0α≥ is reduced to the ΛCDM model. Predictions of the multidimensional model essentially depend on 3 data points for H(z) with z≥2.3. © 2014 IOP Publishing Ltd and Sissa Medialab srl .
Sharov G.S.,Tver State University
Journal of Cosmology and Astroparticle Physics | Year: 2016
Observational manifestations of accelerated expansion of the universe, in particular, recent data for Type Ia supernovae, baryon acoustic oscillations, for the Hubble parameter H(z) and cosmic microwave background constraints are described with different cosmological models. We compare the ΛCDM, the models with generalized and modified Chaplygin gas and the model with quadratic equation of state. For these models we estimate optimal model parameters and their permissible errors with different approaches to calculation of sound horizon scale rs(zd). Among the considered models the best value of χ2 is achieved for the model with quadratic equation of state, but it has 2 additional parameters in comparison with the ΛCDM and therefore is not favored by the Akaike information criterion. © 2016 IOP Publishing Ltd and Sissa Medialab srl .
Zinoviev A.V.,Tver State University
Environmental Archaeology | Year: 2016
The paper examines leather straps associated with avian bones from archaeological excavations in Medieval Russia. These leather straps, found attached to the tarsometatarsi of hunting birds, such as gyrfalcon, peregrine falcon, goshawk and sparrowhawk, constitute components of falconry equipment. A leather strap, secured on the tarsometatarsus of a buzzard, indicates the use of this bird as a decoy during the training of hunting birds. The same is true for the crane and little owl. The loss of other bones of the avian skeletons during the excavation process often leads to the erroneous interpretation of the leather straps with avian tarsometatarsi as amulets. © Association for Environmental Archaeology 2016
Shavrin V.N.,Tver State University
Regional Research of Russia | Year: 2015
The paper discusses subcenters - special places in the settlement systems of municipal districts. In some ways they can be compared with "key settlements" of Great Britain. Subcenters are considered an alternative to municipal district centers. Formal criteria are offered for determining subcenters for NonChernozem Zone. Seventy-seven subcenters are determined in Tver oblast. All municipal districts of the oblast are analyzed for the presence of the mentioned class of settlements. The differences in the network density of centers (municipal and subcenters) in the districts of the oblast are shown. The dependence of the network density of centers (municipal and subcenters) in municipal districts on their economical and geographical position is demonstrated. The genetic types of subcenters in Tver oblast are examined. Among them there are former centers of municipal districts, old trade centers, settlements with favorable transport and geographical location, and rural settlements that have transitioned into small towns or urban-type settlements. Possible decisions to strengthen the role of subcenters in municipal districts are suggested. © 2015 Pleiades Publishing, Ltd.
Nikitin S.A.,Moscow State University |
Skokov K.P.,Leibniz Institute for Solid State and Materials Research |
Koshkid'Ko Yu.S.,Tver State University |
Pastushenkov Yu.G.,Tver State University |
Ivanova T.I.,Moscow State University
Physical Review Letters | Year: 2010
We have investigated the anisotropy of the magnetocaloric effect in a NdCo5 single crystal in a wide range of temperatures, including the spin-reorientation temperature region. In the field μ0H=1.3T in the spin-reorientation region 250-310A K, we discovered a giant rotating magnetocaloric effect of ∼1.6K, caused by rotation of the magnetization vector. The calculations of the anisotropy magnetocaloric effect for the field μ0H=1.3T have been carried out. © 2010 The American Physical Society.
Komarov P.V.,Tver State University |
Khalatur P.G.,University of Ulm |
Khokhlov A.R.,University of Ulm |
Khokhlov A.R.,Moscow State University
Beilstein Journal of Nanotechnology | Year: 2013
Atomistic and first-principles molecular dynamics simulations are employed to investigate the structure formation in a hydrated Nafion membrane and the solvation and transport of protons in the water channel of the membrane. For the water/Nafion systems containing more than 4 million atoms, it is found that the observed microphase-segregated morphology can be classified as bicontinuous: both majority (hydrophobic) and minority (hydrophilic) subphases are 3D continuous and organized in an irregular ordered pattern, which is largely similar to that known for a bicontinuous double-diamond structure. The characteristic size of the connected hydrophilic channels is about 25-50 Å, depending on the water content. A thermodynamic decomposition of the potential of mean force and the calculated spectral densities of the hindered translational motions of cations reveal that ion association observed with decreasing temperature is largely an entropic effect related to the loss of low-frequency modes. Based on the results from the atomistic simulation of the morphology of Nafion, we developed a realistic model of ion-conducting hydrophilic channel within the Nafion membrane and studied it with quantum molecular dynamics. The extensive 120 ps-long density functional theory (DFT)- based simulations of charge migration in the 1200-atom model of the nanochannel consisting of Nafion chains and water molecules allowed us to observe the bimodality of the van Hove autocorrelation function, which provides the direct evidence of the Grotthuss bond-exchange (hopping) mechanism as a significant contributor to the proton conductivity. © 2013 Komarov et al; licensee Beilstein-Institut.
Zinoviev A.V.,Tver State University
Journal of Systematic Palaeontology | Year: 2011
Partial reconstruction of hindlimb myology and syndesmology of Hesperornis regalis, based on fossil and extant comparative anatomical material, is provided. Possessing a combination of morphological features characteristic of modern loons and grebes, H. regalis was somewhat closer to loons in overall hindlimb anatomy. The acetabular foramen indicates that the femoral head of Hesperornis had a more restricted excursion in the acetabulum comparedwith modernAves. The development of femoral retractors m. iliofemoralis and m. caudofemoralis exceeded that of modern foot-propelled diving birds, showing greater protractive forces applied to the femur during the propulsive stroke. The origin of intermediate and lateral portions of m. gastrocnemius reached its maximum in Hesperornis, extending proximally beyond the greater trochanter and migrating onto the cranial surface of the femur. Ligaments of the knee joint, which show typical avian morphology, allowed a high degree of inward-outward rotation of the tibiotarsus,whichwas held close to the body andwas probably enclosed in the thickly feathered skin of the body wall. Flexion-extension movements in the knee joint were highly reduced by the action of well-developed mm. flexores cruris, m. iliofibularis, the postacetabular portion of m. iliotibialis lateralis and m. femorotibialis medialis. The intertarsal joint of Hesperornis possessed a high degree of rotational freedom. In this way it resembled that of loons, showing a loon-like manner of tarsometatarsal movements. This was, however, combined with grebe-like movements of the toes, which undoubtedly had asymmetrical lobes. Hesperornis regalis shows its own independent way of mastering underwater locomotion, which led to the appearance of what became the most specialized avian foot-propelled diver ever known. © 2011 The Natural History Museum.
Samsonov V.M.,Tver State University
Current Opinion in Colloid and Interface Science | Year: 2011
After a short discussion of the main experimental results on the macroscopic and nanosized droplet spreading, a critical review is presented for the publications on the computer simulation of the droplet spreading. As follows from the review, history of investigations in this field of surface science began in 1990s. Special emphasis is placed on articles published during the last 5 years, particularly, in 2010.Some recent advances. It seems that there have seen no significant advances in the course of 2010 into computer simulation of the droplet spreading. At the same time, an attempt to compare computer simulation results with theoretical results for the macroscopic spreading is, no doubt, of interest. It is also of interest that in 2010 the droplet spreading in a liquid medium was simulated, and the wetted area followed the diffusive law. © 2011 Elsevier Ltd.
Zinoviev A.V.,Tver State University
International Journal of Osteoarchaeology | Year: 2012
The aim of this study was to investigate the diversity of dogs in medieval Novgorod. Based on the unique osteological collection of canine bones from layers of 10th to 14th centuries AD, research showed that the 'classical' medium-sized mesocephalic animals were the most widespread in the city in the discussed times. Well suitable for the alarm guarding, they were rarely used for food or skins. Smaller and larger specimens are rare and most likely represent the luxury breeds of upper classes or prosperous citizens. © 2010 John Wiley & Sons, Ltd.