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Nanosystems: Physics, Chemistry, Mathematics

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Our journal "Nanosystems: Physics, Chemistry, Mathematics" is devoted to fundamental problems of physics, chemistry and mathematics concerning all aspects of nanosystems science. It considers both theoretical and experimental problems of physics and chemistry of nanosystems, including methods of their design and creation, studies of their structure and properties, behavior under external influences, and the possibility of use. We accept papers directly or conceptually related to the key properties of nanosystems. Nanotechnology has required the creation of new methods of mathematical modeling and mathematical physics, as well as the development of existing methods for their extension to the study of new objects, many of which were previously simply absent. The corresponding mathematical problems will be covered in our journal. The scope of the journal includes all areas of nano-sciences. Papers devoted to basic problems of physics, chemistry and mathematics inspired by nanosystems investigations are welcomed. Both theoretical and experimental works concerning the properties and behavior of nanosystems, problems of their creation and application, mathematical methods of nanosystem studies are considered. The journal publishes scientific reviews (up to 30 journal pages), research papers (up to 15 pages) and letters (up to 5 pages). All manuscripts are peer-reviewed. Authors are informed about the referee opinions and the Editorial decisions.

Current issue

Vol 7, No 1 (2016): Special Issue: Proceedings of the 12th Biennial International Conference “Advanced Carbon Nanostructures” (ACNS’2015)
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PAPERS, PRESENTED AT THE CONFERENCE

22-29 2
Abstract

The self-organization of water-soluble endometallofullerenes (fullerenols) in solutions has been studied by neutron scattering in connection with their applications (Magneto-Resonance Imaging, X-Ray Tomography). Their functional characteristics depend strongly on molecular self-assembly which may be altered by chemical additives, concentration increase or the magnetic field applied. Polarized neutrons have been used to search paramagnetic fullerenols’ organization into supramolecular structures influenced by the fullerenol concentration and their intensified interactions in a magnetic field.

30-36 5
Abstract

It is well known that graphene, which brought the 2010 Noble Prize in physics to Russian scientists Andre Geim and Konstantin Novoselov, exists as two-dimensional carbon layers. The possible range of graphene applications includes development of field-effect transistors for digital and analog electronics, nanoelectromechanical systems, quantum dots, cold cathodes, supersapacitor, gas sensors, and nearly transparent electrodes and coatings. The possibility of using graphene for hydrogen storage and the manufacture of composite materials is also being studied. Being a two-dimensional material, graphene provides ultimate one-dimensional miniaturization and is a convenient basis for manufacture of different nanoelectronic, nanomechanical and nanochemical devices by lithographic methods. The graphene-based device which is closest to being successfully realized for practical application is the gas sensor. The use of graphene makes it possible to achieve a sensitivity exceeding that of all other materials, less than 1ppb. This device combines the comparative simplicity of manufacture with a wide spectrum of possible applications. It should also be mentioned that the structure of the gas sensor actually reproduces the structure of the field-effect transistor. Thus, the gas sensor can be considered the first stage in the development of intricate transistor electronics based on graphene. The paper briefly reviews growth experiments and studies of graphene films on silicon carbide (SiC) and the development of prototype gas sensors based on this material.

37-43 3
Abstract

DC and AC electrical properties of hybrid films, consisting of carbon nanotubes and tungsten disulfide nanotubes (and fullerene like nanoparticles) were studied within the 2 – 300 K temperature range and over the 20 Hz – 1 MHz frequency range. The temperature dependences of the resistance R(T) exhibit behavior typical for the fluctuation-induced tunneling model in the intermediate temperature range. Analysis of the dependences of real and imaginary components of the impedance on the frequency (Z’(f) and Z”(f)) demonstrates the rising role of the contact barriers between carbon nanotubes inside hybrid films, consisting of the carbon nanotubes and inorganic tungsten disulfide nanotubes as the temperature was decreased. The active component of the impedance was found to prevail in the AC electrical properties of the hybrid films, consisting of multi-wall carbon nanotubes and WS2 nanoparticles over the entire available temperature range.

44-50 2
Abstract

We discuss a number of hydrocarbon structures whose cohesive energy is not worse than that of benzene and graphanes. These structures can be regarded as sublattices of known carbon structures so the strain exerted on the crystal lattice is minimal and caused mostly by the steric interactions of hydrogen atoms. Possible synthetic routes are proposed. Due to their exceptional mechanical, structural and electrical properties, these crystal structures may have utility as mechanical, optoelectronic or biological materials.

51-57 3
Abstract

The electromagnetic radiation of electrons in the corrugated graphene has been studied in the presence of a transport electric current in the ballistic regime. We considered here the impact of ripples in monolayer graphene on its electromagnetic properties. Electromagnetic radiation was actually calculated with a use of the standard electromagnetic theory. Two cases: those of regular and random structures were analyzed. The nonlinear relationship between the random height function h(x, y) and the gauge field is shown to create a central radiation frequency distribution peak.

58-59 3
Abstract

The ripples are considered an incommensurate superstructure in a two-dimensional crystal, appearing as a result of the formation of periodic solutions in an in-plane optical phonon subsystem. The possible instability of the flexural subsystem is also discussed.

60-64 3
Abstract

A method to synthesize graphene materials using a DC high current divergent plasma torch has been developed. Carbon atoms were generated by the decomposition of propane-butane, methane and acetylene in a thermal plasma jet. The graphene materials were characterized by electron microscopy, thermogravimetry, Raman spectroscopy. The influence of the experimental conditions on the morphology and phase composition of the synthesis products was investigated. The optimal conditions for the synthesis of high-purity graphene flakes have been found.

65-70 3
Abstract

The preparation of Langmuir – Blodgett (LB) films based on graphene oxide and the study of their structure and optical properties are presented. Graphene oxide dispersions were prepared in different solvents and the stability of each solution was studied. The measurements have shown that most stable dispersions were prepared in tetrahydrofuran, but in acetone, the concentration of graphene oxide is higher. Therefore, graphene oxide monolayers were formed from acetone dispersions. The physicochemical properties of graphene oxide monolayers at the water-air interface were studied. The LB films were deposited onto solid substrates according to Y-type (transfer during downward and upward stroke of substrate) and Z-type transfer (deposition during the upward stroke only). The absorption spectra of graphene oxide LB films exhibit a broad band in the ultraviolet and visible region of the spectrum. The optical density of the film obtained according to the Y-type transfer is greater than the optical density of the film prepared according to the Z-type transfer. The transparency of the films in the visible region of the spectrum is greater than 90 %. As it was shown by SEM images, the films obtained according to the Y-type transfer are more uniform in structure.

71-80 3
Abstract

The current paper presents results from an extended neutron scattering study of a three-part set of parent and reduced graphene oxides (GO and rGO, respectively) of different origins. The first part concerns the rGO of natural origin represented by shungite carbon, the second and third parts are related to synthetic GO/rGO pairs with the latter produced during either chemical treatment or via thermal exfoliation of the parent GO, respectively. The study involved both the neutron diffraction and inelastic neutron scattering. The one-phonon amplitude-weighted density of vibrational states G(ω) represents the inelastic incoherent neutron scattering spectra of the products. Common characteristics and individual distinctions of the studied species are discussed.

81-86 3
Abstract

We have studied the process of UV reduction of wrinkled grahpene oxide films, deposited on silicon substrate from ethanol suspension. In order to avoid destruction of graphene oxide via ozone formation from ambient air, samples were protected by argon atmosphere during UV irradiation. Using the analysis of back scattering spectra for medium energy ions, we have found that the UV irradiation mediated reduction process produced significantly decreased carbon content on the substrate surface. The decrease in the carbon content was accompanied by a smoothing of the films during reduction to graphene. We suppose that the observed effect is related to the oxidation of carbon atoms in the graphene scaffold of graphene oxide to carbon monoxide or dioxide by the oxygen from the graphene oxide (GO) itself. One has to consider this when developing a process for the preparation of graphene films using the UV-mediated reduction of graphene oxide.

87-92 3
Abstract

This paper presents the results for the quantum-chemical modeling of V2 and V – C = C – V divacancy defects configurations on the C(111) – 2×1 diamond surface. We provide calculations for the geometric, electronic, and energy characteristics for these configurations. Energy characteristics of water and hydrogen molecule adsorption on the surface with divacancy defects are estimated. The presence of V2 and V – C = C – V divacancy defects are shown to change the mechanism and energy characteristics of molecular adsorption.

93-98 3
Abstract

Since their discovery in the early 1990’s, carbon nanotubes (CNTs) have become the subject of numerous investigations into their electronic structure and energy spectrum parameters as well as their physico-chemical properties. Due to their high surface activity, nanotubes can be used as base components for the fabrication of various types of composites. However, along with carbon nanotubes, current research also focuses on theoretical and experimental investigation of non-carbon nanotubes, namely recently discovered boron-carbon nanotubes with different concentrations of boron in them (25 % or 50 %). This article presents the results of theoretical research into the properties of boron-carbon nanotubes (BCNTs) within the framework of an ionic-built covalent-cyclic cluster model and an appropriately modified MNDO quantum chemical scheme, as well as DFT method. The authors studied mechanism of Cl and O atoms sorption onto the external surface of single-walled armchair nanotubes. As result of the study, geometrical optimization of the sorption complexes was defined, and sorption energy values were obtained.

99-103 3
Abstract

The kinetics for the dissolution of fullerene C60 in N-methyl-2-pyrrolidone (NMP) solvent are investigated through measurements of the stirring speed and temperature dependence of the UV-Vis absorption spectra. We develop a model for the kinetics of simultaneously occurring processes in the solution, employing a system of simple kinetic equations and obtain the corresponding parameters dependence on preparation conditions. The obtained results will allow one in the future to consider these effects when modeling the slow growth kinetics of large clusters in C60/NMP solutions.

104-110 3
Abstract

The solvent-exchange process from toluene was used for preparing aqueous dispersions of C60 and C70 without preconcentration with final concentrations of 180 ± 2 and 62 ± 1 µM, respectively, which exceeds the previously reported maximum concentrations for C60 more than 6-fold; for C70 such an aqueous dispersion is prepared for the first time. The residual quantity of the organic solvent and low-molecular compounds determined by headspace GC-MS was not more than 1 ppb. The procedure for the determination of fullerenes in aqueous dispersions is developed using a total organic carbon analyzer and absorption spectra; LOD, 50 nM, LOQ, 200 nM by TOC. Spectrophotometric determination of fullerenes in their aqueous dispersions was optimized: for C60 at 268 nm: LOD, 0.1 µM, LOQ, 0.3 µM, for C70 at 218 nm: LOD, 0.1 µM, LOQ, 0.3 µM. RSD mixture quantification by Vierordt’s method in the range of 2 – 20 µM does not exceed 0.14 for C60 and 0.09 C70. RSD for toluene fullerene mixtures by Vierordt’s method in the range of 2 – 20 µM does not exceed 0.10 for C60 and 0.06 for C70.

111-117 3
Abstract

Four CF3 derivatives of C78, C78(2)(CF3)10/12 and C78(3)(CF3)12/14, have been isolated via HPLC from the products of high-temperature trifluoromethylation of a C76–C96 fullerene mixture or a C78 fraction. Their molecular structures were determined by single crystal X-ray crystallography using synchrotron radiation. The addition patterns of the new compounds are compared with each other and with the previously known C78(2)(CF3)10 and C78(3)(CF3)12.

118-124 3
Abstract

Star-shaped macromolecules with C60 fullerene branching centers were used as modifiers of poly(2.6-dimethyl-1.4-phenylene oxide) matrix to obtain mixed matrix membranes. Two types of star modifiers were synthesized i) six-arms star with six polystyrene arms grafted onto C60 center and ii) twelve-arms hybrid star with six polystyrene arms and six copolymer poly(2-vinylpyridine)-block-poly(tert-butylmethacrylate) arms grafted onto C60 center. The membrane structures were studied by scanning electron microscopy. The transport properties of the membranes were determined by using sorption and pervaporation tests toward methanol and ethylene glycol over a wide concentration range. All membranes showed high affinity for methanol. The separation factor reached its maximum level at 5 wt% modifier concentration in the membrane. Polar hybrid arms were shown to change the membranes’ morphologies and considerably improve their transport properties.

125-132 2
Abstract

The photopolymerization process and the stability of the C60 photo-oligomers at elevated temperature in the molecular donor-acceptor fullerene complex {Pt(dbdtc)2}·C60 (C60 complex with platinum dibenzyldithiocarbamate) and pristine fullerite C60 are studied by Raman spectroscopy. Fast polymerization, manifested by the appearance of additional peaks in the frequency region of the Ag(2) pentagon-pinch (PP) mode of the C60 molecule, was observed upon sample illumination at 514.5 and 532 nm, even at low laser power density as well as at 785 nm at higher power density. The frequencies of the new peaks are in accordance with the empirical dependence of the PP-mode frequency on the number of the sp3-like coordinated carbon atoms per molecular cage. The temperature dependence of the polymer content under constant laser power density reveals the decomposition of the photo-oligomers to monomers at ∼ 350 K in the fullerene complex {Pt(dbdtc)2}·C60 and at ∼ 410 K in the case of the pristine C60. These values are considerably smaller than the decomposition temperature of 525 – 565 K for the crystalline polymers of C60.

133-139 3
Abstract

The pressure-assisted photopolymerization in the fullerene complex {Cd(dedtc)2}2·C60 (fullerene complex with cadmium diethyldithiocarbamate) observed in the pressure region between 2.24 and 5.99 GPa was studied in detail. After a phase transition near ∼ 2 GPa, the Raman spectra exhibit time-dependent changes under prolonged laser illumination regarding the appearance of new peaks in the frequency region of the Ag(2) mode of the C60 monomer. These peaks are related to the fullerene oligomers with a different number of sp3-like coordinated carbon atoms per molecular cage. The polymer content increases with the laser power density and exposure time, while for a fixed laser power, its saturated value is independent of pressure. Outside the pressure range 2.24 – 5.99 GPa, photopolymerization is suppressed.

140-145 3
Abstract

This paper describes the technique for rapid determination of endohedral metallofullerene (EMF) content in a fullerene mixture (FM). The methods of mass spectroscopy and atom emission element analysis underlay at the technique. By the method of mass spectroscopy, the type of EMF with atom-guest is registered and by the method of emission spectroscopy, the quantity of that element which is contained in the FM is determined. The technique may be used for rapid determination of EMF weight percents in the FM in the specific case if only one type of EMF is present, and of EMF average content if there are different types of EMF are present. The technique is demonstrated through the example of analysis of FM with Y, which was extracted from the carbon condensate (CC) by different solvents (C5H5N and CS2).

146-152 3
Abstract

Fullerenes C2n, endometallofullerenes Gd@C2n, Gd@C82 and water-soluble Gd@C2n(OH)38−40 derivatives were synthesized. These substances’ survival dependences on the accumulated flux (1016 – 1019 neutron/cm2) of neutron irradiation over a wide spectrum of energies (from thermal to fast) in the WWR-M reactor zone (Petersburg Nuclear Physics Institute) have been examined.

153-157 3
Abstract

In this paper, we describe application of the adrenaline autoxidation reaction to determine the antioxidant activity of fullerenols C60, C70 their mixture with higher fullerenol and endohedral fullerenol Y@C82. It was shown that the adrenaline autoxidation reaction can be applied to determine the antioxidant activity of fullerenols. The antioxidant activity of C70 fullerenol was higher than that of C60 fullerenol Additionally, the antioxidant activity of Y@C82 fullerenol was higher than that of C70 fullerenol.

158-160 3
Abstract

The uptake of superparamagnetic Fe7C3@C nanoparticles into living cells and their behavior once inside the cell was investigated. The cells used were shown to absorb the nanoparticle aggregates over the first 30 minutes. After absorption, these aggregates moved towards the center of the cell and accumulated near the cell nucleus. No toxic effects on cell physiology were observed. In a magnetic field, the particles aligned in the cells along magnetic lines and shifted to the magnet’s side. During long-term cultivation, Fe7C3@C nanoparticle aggregates were ultimately discarded via exocytosis.

161-168 3
Abstract

In this work, multiwall carbon nanotubes (MWCNT) were functionalized with silver nanoparticles using two different methods of incorporation. Characterization of these composites was done using Raman spectroscopy and Transmission Electron Microscopy (TEM) and the antibacterial properties were measured using method of dilution and plating. The four-point probe method was used to measure the resistivity of the nanocomposite thin films made via the spin coating method.

169-174 2
Abstract

The evolution of the electron transport character in thin films of Mo–C nanocomposites is studied over the metal concentration range 0.14 – 0.3 at temperatures from 4.2 to 400 K. It is shown that conductivity of the Mo–C nanocomposites demonstrates the distinct power-like behavior in the two temperature intervals separated at 20 – 25 K. The concentration dependences of the power exponent in both temperature intervals are characterized by the expressed minimum at Mo content close to 0.2 varying over the range 0.25 – 1.0. The experimental data are discussed and simulated in the model of inelastic tunneling of the electrons in amorphous dielectrics in the framework of the effective medium approximation.

175-179 3
Abstract

The specific surface area is a key characteristic of carbon materials used in supercapacitor electrodes. In this paper, the use of a methylene blue technique for specific surface area determination is presented. Values for the specific surface area, determined by a new method, provide better correlation with theoretical values for the specific electrical capacity of highly-porous carbon electrodes than the values measured by the common BET method. Additionally, the methylene blue adsorption method is thought to characterize carbon adsorption activity in relation to a supercapacitor electrolyte.

180-184 5
Abstract

This paper presents results of the experimental studies of the properties of silica-based nanocomposites with filler in the form of carbon nanotubes by dielectric relaxation and positron annihilation spectroscopy. Based on these results, techniques for diagnosis and control of the investigated materials were proposed.

185-189 3
Abstract

In our research, the method of manufacturing an Al-carbon nanotube (CNT) composite by hot pressing and cold rolling was attempted. The addition of one percent of multi-walled carbon nanotubes synthesized by OCSiAl provides a significant increase in the ultimate tensile strength of aluminum. The tensile strength of the obtained composite material is at the tensile strength level of medium-strength aluminum alloys.

190-197 3
Abstract

A comparative study of Cu-C60/70 and Cu-Cg composites obtained by mechanical alloying has been performed by means of scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. It has been demonstrated that high stress-related effects, which take place during the mechanochemical synthesis of Cu- C60/70 and Cu-Cg composites with a nanocrystalline structure, result in the formation of an oversaturated solid solution of carbon in copper, Cu(C). The morphology and the parameters of the crystal lattice aCu(tMA) and the sizes of the crystallites L(tMA) of the powders obtained depend on the deformational stability of fullerite and graphite and also on their reactivity to adsorbed oxygen.

198-203 3
Abstract

A ceramic matrix composite based on zirconium dioxide doped with carbon nanotubes (CNTs) and metallic silver as a plastic binder was produced by hydrothermal synthesis from ceramic precursor and a CNTs suspension followed by critical point drying of the synthesized hydrogel and metallic silver deposition on ceramic composite aerogel fragments from a AgNO3 solution. Multi-indentation loading of the composite has revealed two types of mechanical response: 1) hardness decreasing with an increasing of number of cycles and 2) significant increasing of hardness with an increasing number of indentations. Local chemical composition analysis has revealed correlations between the composite hardness and the presence oxygen atoms for first type and silver and yttrium atoms for second type of mechanical response respectively.

210-213 3
Abstract

Shungites have been studied by high-resolution transmission electron microscopy (HRTEM). Two types of carbon layers have been revealed in shungites by HRTEM. The first type, graphite-like carbon layers are characterized by strongly marked hexagonal symmetry. The second type are remarkable for imperfections connected with insignificant disorder in the direction of fringes and the distance between them, and can result from point defects or the pentagonal and heptagonal carbon rings that are signs of fullerene-like structures.

214-219 3
Abstract

The temperature dependence of electrical conductivity and the shielding effectiveness of shungites have been studied at temperatures ranging from 77 to 300 K. The idiosyncrasies of temperature dependences for measuring electrical parameters were determined. Correlations of the π + σ plasmon energies with changes in the frequency dependence of shielding effectiveness on temperature were determined.

220-225 3
Abstract

Carbon is represented in modern nanomaterials by a large variety of modifications. Various methods and technologies have been developed to create these various forms. Methods utilizing laser irradiation constitute a large portion of these techniques. The action of laser pulses upon graphite may result in the exfoliation of graphene layers. This paper presents the results of implementing method of laser-induced cleavage of graphite in liquid nitrogen using femtosecond laser radiation pulses. The process of obtaining graphene from the laser processing of graphite is accompanied by the formation of various types of low-dimensional carbon structures.

226-233 5
Abstract

We extend our method formerly suggested for structure refinement of the amorphous sp2 carbon, based on neutron or x-ray diffraction, and applied to amorphous fullerene and its derivatives produced by vacuum annealing. To diagnose heterogeneous media, the method uses the rigid body molecular dynamics simulations of the domain-like packing for a predefined set of structural blocks. Previously, the sensitivity of the results to the variability of mutual positions of these structural blocks was analyzed in two limiting cases: (A) any domain contains only identical structural blocks and (B) all domains are the identical mixtures of many different structural blocks with variable packing of the blocks. Here, we extend this analysis to intermediate cases which correspond to domains of the type “B” with the subdomains of the type “A”. Such a structuring corresponds to a partial destruction of the nanoscale structure of the sample (e.g. by low-temperature annealing).

234-243 7
Abstract

Thermal stability in combustion reaction for natural graphite, graphene and several expanded graphite phases were studied; the kinetic parameters of the oxidation reaction were calculated for two samples. Natural graphite (crystalline particles 200 – 300 µm) has the maximum stability (E1 = 201 ± 2 kJ/mol, lg A1 = 7.1 ± 0.1), while multilayer graphene is the most reactive (E2 = 120 ± 1 kJ mol−1, lg A2 = 4.3 ± 0.10). The different sample grain sizes and their different structures result in different thermal stabilities: both in the reaction zones location (i.e. in the topochemical equation forms), and in the kinetic parameters’ values.

244-252 3
Abstract

The evolution of paramagnetic centers (PMC) and conductivity of graphite oxide (GO) during its thermal reduction has been studied by electron paramagnetic resonance (EPR) at 150 and 165 ◦C. The GO samples for the study were prepared by systematically varying the KMnO4/Graphite weight ratios in the oxidation reaction. It has been shown that the PMC concentration increase in GO correlates with the intense evolution of gaseous products originating from the former oxygen-containing species of GO. The PMC concentration decrease has been described by the kinetic equation of the first order with an effective ke and an activation energy value of 33 kcal/mol. The values of ke decreased with increasing the quantities of KMnO4 used in graphite oxidation reaction. The changes in GO conductivity were followed by measuring the microwave power absorption in the EPR-spectrometer resonator. The conductivity changes correlated with the decay of the radicals and occurred after the decomposition of the oxygen-containing groups was complete.

253-259 3
Abstract

The article presents the results from the study of carbon nanotube (CNT) interaction with the main products generated in the process of oil “aging”, in particular with a molecule of sulfurous acid, hydroxyl group, ferrous and aluminium oxides. The purpose of the paper is to prove the possibility of oxygen atom adsorption on the outside face of CNT.



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