Sandwich-like composite on the base of graphene and Co3O4 nanocubes is a prospect material for electrodes of chemical sources of current. The total capacitance of this material is mainly contributed by quantum capacitance that depends on a change of Fermi level during charge/recharge cycles. The main goal of this paper is to calculate the dependence of Co3O4@graphene’s quantum capacitance on mass ratio of its components. The obtained results can be applied in the design of modern supercapacitors and lithium-ion batteries.
We have investigated the effect of doping a graphene matrix with silicon atoms on the structure, vibrational and electronic spectra. The impact of substitution on the shape and intensity of the D line in the RAMAN spectrum is shown. It is demonstrated that the shape of the doped sheet depends on the location of Si atoms, which can lead to a significant increase in its dipole moment.
In this paper we developed the model of GHz- and THz-waves detector on the base of single-walled carbon nanotube functionalized with trimer of fullerene C60 and free fullerenes C36 and C80. It was discovered the amplitude of internal fullerenes’ oscillation depends on temperature and strength of electromagnetic wave. It was found the parameters of incident wave when fullerene C36 and C80 reach wall of carbon nanotube at the distance of 1.7 Å that is not sufficient to form covalent bonds. At such regime fullerenes accept charge from carbon nanotube that leads to change of system’s IV-curve. Discovered phenomena can be the basis for design of nanodetector.
The paper performs multiscale modeling of interaction between hybrid patch and blood vessels as well as patch with heart tissue by finite element method. Patch represented 3-dimensional cellular engineering structure consisted of three layers: carbon nanotube carcass, lipids of albumin and collagen and the aminosugar of chitosan. It was found that maximum stresses were observed in the contact area between media and the advent layers. It was found that in diastole the maximal values of patch displacement as well as the greatest stresses were concentrated in the area of contact between heart and patch.
Quantitative theoretical studies of long-range electron transfer are still quite rare and require further development of computational methods for the analysis of such reactions. We considered the electron transfer reaction in rutenium-modified derivatives of cytochrome b562 with advanced modeling techniques. We conducted a series of ab initio calculations of the donor/acceptor interaction in protein fragments and compared the calculated electron velocity with available experimental data. Our approach takes into account the co-factor of the electronic structure and the impact of the solution on a donor-acceptor interaction. This allows us to predict the absolute values of the electron transfer rate unlike other computational methods which provide only qualitative results. Our estimates with good accuracy repeat the experimental values of electron transfer rate. It was found that the electron transfer in certain derivatives of cytochrome b562 is mainly caused by "shortcut" conformations in which the donor/acceptor interactions are mediated by the interaction of Ru-unbound ligands with groups of the protein surface. We argue that a quantitative theoretical analysis is essential for detailed understanding of electron transfer in proteins and mechanisms of biological redox reactions.
In this paper we study the behavior of [2.2.2] cryptand with various metal ions (Na, K, Eu, Fe) inside the armchair carbon nanotube. To identify regularities of behavior for cryptand inside a nanotube we carried out a series of numerical experiments in molecular dynamics using Amber force field at different temperatures and under influence of external electric field. We have established the dependence of the oscillation frequency of the cryptand inside a carbon nanotube. On the basis of the established effect of fluctuations for cryptand inside the nanotube is predicted that such complexes can be used as miniature radiating systems.
Due to the increasing demand for functionalization of graphene and its application as a functional element of real electronic and / or mechanical devices, as well as due to its unique adhesive and sensory abilities the actual problem is the use of graphene as a substrate on which the assembly of supramolecular structures. Elements of such structures can be different molecules driven by external factors, and can be easily transported on graphene. These molecules primarily include miniature spheroidal fullerenes easy to navigate on the surface of graphene, in particular icosahedral C60. The aim of this work was to find an effective method of manipulation of fullerene C60 on graphene. As such method we proposed to introduce in graphene sheet structural defect of the atomic framework namely defect Stone-Wales (pentagon-heptagon pairs). Another structural defect studied in this paper is adsorbed on the Stone-Wales defect hydrogen atom. Molecular dynamics and tight binding method were applied to calculate the location of the molecule C60 on graphene sheet and its movement. To identify the regulatities of behavior of fullerene on graphene sheet we carried out a series of numerical experiments at different temperatures. In this paper we calculated the energy profile of interaction between fullerene and graphene sheet. Obtained results showed that forming on the surface of the graphene sheet defects in a certain way, one can control the trajectory of molecules on graphene.
In this work, we study the behavioral regularity of fullerene C20 inside the icosahedral outer shell of fullerene C240. The feature of such two-shell fullerenes is that the internal fullerene will move at low temperatures in a certain way: between the potential wells. The aim of this work is to reveal the regularities for motion of small fullerenes in nanospace of large external icosahedral fullerene, including the identification of the spatial configuration for a multi-well potential of interaction between two objects and prediction of possible movement for the internal object between potential wells. For the fullerene C20 it was found twenty potential wells in the direction of the fifth order axes for icosahedron of fullerene C240 cage, thirty towards in the direction of the middle of the ribs and twenty potential wells towards centers of the faces of the icosahedron. The prediction of possible moving for the internal object between potential wells and the regularities of this movement were made based on the relief analysis of the interaction energy surface of fullerenes. The numerical simulation of C20 motion in the field of C240 was carried out to test the prediction of movement. As results of the experiment, it was found that the fullerene C20 is easy to jump between the potential wells even at low temperatures up to 300K. Molecular dynamics simulations confirmed our conclusions about regularities of C20 movement between potential wells. Thus, one can conclude that the analysis of the topology of the energy surface of van der Waals interaction between the components of nanoparticles gives a true predictive picture of the regularities of the internal molecule behavior. Probably, the phenomenon of fullerene C20 movement in a cell of another fullerene can be used in modern technologies, such as determining a local temperature by increase of jumping velocity.
The results of theoretical study of bilayer fullerene C60@C540 are presented in this paper. In order to identify regularities of internal fullerene movement in the field of the outer shell retaining potential multiwell potential of C60 and C540 fullerenes interaction was calculated. On the basis of the two-shell fullerene structure topology data and analysis of the fullerenes interaction energy surface relief possible options of C60 tunneling between potential wells are predicted. Compiled forecast is confirmed by the data of numerical experiment.
In the process of field emission surface of carbon nanotubes is heated, that may lead to the rapid destruction of the emitter based on them. Therefore, the problems of heat reducing and the destruction of carbon nanotubes prevention are important. Experimental study of the thermal conductivity of isolated CNT is time consuming and expensive process, so it is better to use the numerical models to understand the process of heat transfer in carbon nanotubes. In this work the change of the nanotubes thermal conductivity was investigated with increasing length and diameter of the nanotubes and the number of defects Stone-Wales.
The results of the theoretical and experimental investigations of the emission properties of the partitioned carbon nanotubes are presented in this paper. We have calculated ionization potential and energy gap of the energy spectrum for stable carbon partitioned carbon nanotube (15,15) of the smallest diameter by means of the tight-binding method. Also we have developed the original synthesis technique of the partitioned carbon nanostructures. This synthesis technology provides the high efficiency of the partitioned carbon nanotubes growth. As a result of calculations it was established that the emission properties of the infinite partitioned carbon nanotubes at the increasing of the distance between the bridges are better in comparison to the emission properties of the hollow nanotubes.
Model of terahertz radiation sources was developed in this work. This model based on the nanopeapod: carbon nanotube
(10, 10) with incapsulated chains of the fullerene C60. Simulation of the nanoemitter action was carried out by means of
the molecular-mechanical model. The length of the considered nanotube is equals to 10.3 nm, and radius of this tube is
equals to 1.35 nm. It was found that to generate the radiation in terahertz range it is necessary to apply the external field
with strength of 1⋅106 V / cm to our system. The moving fullerene C60 has a charge of +3е, and the nanotube has a charge
of -3е. It was established that the field emission process from the surface of the nanotube is not observed in this case.
The submitter model of nanoemitter works with a frequency 0.36 THz at a field strength of 1⋅106 V / cm.
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