279 research outputs found
Melting temperature of graphene
We present an approach to the melting of graphene based on nucleation theory
for a first order phase transition from the 2D solid to the 3D liquid via an
intermediate quasi-2D liquid.
The applicability of nucleation theory, supported by the results of
systematic atomistic Monte Carlo simulations, provides an intrinsic definition
of the melting temperature of graphene, , and allows us to determine it.
We find K, about 250 K higher than that of graphite using the
same interatomic interaction model. The found melting temperature is shown to
be in good agreement with the asymptotic results of melting simulations for
finite disks and ribbons of graphene. Our results strongly suggest that
graphene is the most refractory of all known materials
Problems of theory of translation in the light of intercultural cooperation
Nowadays there are a lot of theoretical and aesthetic problems of theory of translation in the light of contemporary processes of globalization of social and communicative links. The problems of Ukrainian cultural space, narrowing of lexical layers and the interrelation of theory and practice of literary translation are of considerable importance
Self-Consistent Screening Approximation for Flexible Membranes: Application to Graphene
Crystalline membranes at finite temperatures have an anomalous behavior of
the bending rigidity that makes them more rigid in the long wavelength limit.
This issue is particularly relevant for applications of graphene in nano- and
micro-electromechanical systems. We calculate numerically the height-height
correlation function of crystalline two-dimensional membranes,
determining the renormalized bending rigidity, in the range of wavevectors
from \AA till 10 \AA in the self-consistent screening
approximation (SCSA). For parameters appropriate to graphene, the calculated
correlation function agrees reasonably with the results of atomistic Monte
Carlo simulations for this material within the range of from
\AA till 1 \AA. In the limit our data for the
exponent of the renormalized bending rigidity is compatible with the previously known analytical results for the
SCSA . However, this limit appears to be reached only for
\AA whereas at intermediate the behavior of
cannot be described by a single exponent.Comment: 5 pages, 4 figure
Atomistic simulations of structural and thermodynamic properties of bilayer graphene
We study the structural and thermodynamic properties of bilayer graphene, a
prototype two-layer membrane, by means of Monte Carlo simulations based on the
empirical bond order potential LCBOPII. We present the temperature dependence
of lattice parameter, bending rigidity and high temperature heat capacity as
well as the correlation function of out-of-plane atomic displacements. The
thermal expansion coefficient changes sign from negative to positive above
K, which is lower than previously found for single layer graphene
and close to the experimental value of bulk graphite. The bending rigidity is
twice as large than for single layer graphene, making the out-of-plane
fluctuations smaller. The crossover from correlated to uncorrelated
out-of-plane fluctuations of the two carbon planes occurs for wavevectors
shorter than nmComment: 6 pages, 7 figures
Thermomechanical properties of graphene: valence force field model approach
Using the valence force field model of Perebeinos and Tersoff [Phys. Rev. B
{\bf79}, 241409(R) (2009)], different energy modes of suspended graphene
subjected to tensile or compressive strain are studied. By carrying out Monte
Carlo simulations it is found that: i) only for small strains () the total energy is symmetrical in the strain, while it
behaves completely different beyond this threshold; ii) the important energy
contributions in stretching experiments are stretching, angle bending,
out-of-plane term and a term that provides repulsion against
misalignment; iii) in compressing experiments the two latter terms increase
rapidly and beyond the buckling transition stretching and bending energies are
found to be constant; iv) from stretching-compressing simulations we calculated
the Young modulus at room temperature 350\,N/m, which is in good
agreement with experimental results (340\,N/m) and with ab-initio
results [322-353]\,N/m; v) molar heat capacity is estimated to be
24.64\,J/molK which is comparable with the Dulong-Petit value,
i.e. 24.94\,J/molK and is almost independent of the strain; vi)
non-linear scaling properties are obtained from height-height correlations at
finite temperature; vii) the used valence force field model results in a
temperature independent bending modulus for graphene, and viii) the Gruneisen
parameter is estimated to be 0.64.Comment: 8 pages, 5 figures. To appear in J. Phys.: Condens. Matte
Digestion and metability in the human body
Today, the process of digestion is well known. This was made possible thanks to the efforts of scientists who have tried for many years to figure out what happens in the body when we swallow food. This involuntary process has been a mystery for a very long tim
Systemic citrate load during continuous renal replacement therapy is not negligible and can be predicted using indirect methods
Analysis of the Northern (Arctic) federal university’s language learning model
В статье авторами приводится метод моделирования для построения языкового образования в современном университете, подчёркивается роль языковой политики университета в определении пути развития языкового образования. Рассматривается модель языкового образования, представленная в программе развития САФУ, и анализируются в соответствие с принципами непрерывности образовательного процесса. На основе этого анализа предлагается собственная модель языкового образования, и обосновываются её преимущества.The authors of this article give method of modeling to scheme language learning at modern university; emphasize the role of language policy at university to determine ways of language learning development. The model of language learning given in the program of development of NArFU is examined and analyzed in compliance with principles of the life-long education. On basis of this analysis the authors’ model of language learning is given and its advantages are proved
Problems of theory of translation in the light of intercultural cooperation
Nowadays there are a lot of theoretical and aesthetic problems of theory of translation in the light of contemporary processes of globalization of social and communicative links. The problems of Ukrainian cultural space, narrowing of lexical layers and the interrelation of theory and practice of literary translation are of considerable importance
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