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Papers by Nurlan Almassov

Journal of Non-Crystalline Solids

Chemical Journal of Kazakhstan

Among alternative sources of energy, such as solar, wind, and hydrogen energy, biofuel occupies a... more Among alternative sources of energy, such as solar, wind, and hydrogen energy, biofuel occupies a special place because it has a few useful properties. Compared to the current price of gasoline,the price of biofuel is very low. During its use, biofuel releases less greenhouse gases into the environment and is less flammable. However, in order to support biofuel, it is necessary to purify its composition from unnecessary glycerol, methanol, and free fatty acids. Free fatty acids in biofuel are flammable and pollute car engines. Various ionic liquids have been developed for the purification of biofuel. One of them is 1-butyl-3-methylimidazolium dicyanamide. The purpose of this work is to study the state of purification of free fatty acids in biofuel by 1-butyl-3-methylimidazolium dicyanamide at the molecular level using chemical quantum calculations. Methodology. HyperChem PM3 method was used for quantum chemical calculations of chemical structures, molecular electrostatic potentials,...

Polymers

In this study, the mechano-chemical properties of aromatic polymer polyetheretherketone (PEEK) sa... more In this study, the mechano-chemical properties of aromatic polymer polyetheretherketone (PEEK) samples, irradiated by high energy electrons at 200 and 400 kGy doses, were investigated by Nanoindentation, Brillouin light scattering spectroscopy and Fourier-transform infrared spectroscopy (FTIR). Irradiating electrons penetrated down to a 5 mm depth inside the polymer, as shown numerically by the monte CArlo SImulation of electroN trajectory in sOlids (CASINO) method. The irradiation of PEEK samples at 200 kGy caused the enhancement of surface roughness by almost threefold. However, an increase in the irradiation dose to 400 kGy led to a decrease in the surface roughness of the sample. Most likely, this was due to the processes of erosion and melting of the sample surface induced by high dosage irradiation. It was found that electron irradiation led to a decrease of the elastic constant C11, as well as a slight decrease in the sample’s hardness, while the Young’s elastic modulus decre...

In our work, we have studied the formation of choline chloride based NADESs using DFT calculation... more In our work, we have studied the formation of choline chloride based NADESs using DFT calculations, and all-atom classical Molecular Dynamics (MD) simulations. In our DFT calculations, the ground state geometry optimizations were performed in the gas phase using DFT B3LYP 6-31+G(d) level of theory. Moreover, all-atom classical Molecular Dynamics simulations were implemented using Gromos force eld. The DFT calculation results revealed the formation of NADESs via formation (creation) of binding between chlorine and choline, and chlorine and glucose. Next, the results of all-atom classical Molecular Dynamics simulations, based on the time average of the equilibrated production run of MD simulations, stated that the nitrogen atom of choline ion, and chloride ion have greater interactions, while chloride ion have also greater interaction with glucose during formation of NADES. Highlights Intermolecular interactions of NADES were studied by DFT calculations and all-atom classical Molecular Dynamics simulations.

Effects of electron-beam processing on the structure and mechanical properties of poly-ether-ethe... more Effects of electron-beam processing on the structure and mechanical properties of poly-ether-ether ketone (PEEK) were studied by XRD and tribological tests. An ambiguous change in the mechanical properties of the irradiated samples was found. In particular, the wear rate of sample 1 is higher than that of the unirradiated original sample, while it is lower for samples 2-7. Sample 4 had the lowest wear rate, and most likely the changes in the mechanical properties of the samples were due to the transformation of their amorphous component. Comparison of the X-ray spectra of the irradiated and unirradiated samples did not reveal any differences in their crystal structure.

Membranes

In this paper, we demonstrate a new, highly efficient method of crosslinking multilayer graphene,... more In this paper, we demonstrate a new, highly efficient method of crosslinking multilayer graphene, and create nanopores in it by its irradiation with low-energy argon cluster ions. Irradiation was performed by argon cluster ions with an acceleration energy E ≈ 30 keV, and total fluence of argon cluster ions ranging from 1 × 109 to 1 × 1014 ions/cm2. The results of the bombardment were observed by the direct examination of traces of argon-cluster penetration in multilayer graphene, using high-resolution transmission electron microscopy. Further image processing revealed an average pore diameter of approximately 3 nm, with the predominant size corresponding to 2 nm. We anticipate that a controlled cross-linking process in multilayer graphene can be achieved by appropriately varying irradiation energy, dose, and type of clusters. We believe that this method is very promising for modulating the properties of multilayer graphene, and opens new possibilities for creating three-dimensional ...

Journal of information and communication convergence engineering, 2011

The absence of deep traps for electrons in the spectrum of As 40 Se 30 S 30 localized states film... more The absence of deep traps for electrons in the spectrum of As 40 Se 30 S 30 localized states films obtained by ion sputtering was determined. Bipolar drift of charge carriers was found in amorphous As 40 Se 30 S 30 films of chalcogenide glassy semiconductors, obtained by ion-plasma sputtering of high-frequency, unlike the films of these materials obtained by thermal evaporation.

Journal of Non-Crystalline Solids, 2012

Switching and memory effects in as-deposited amorphous Ge 2 Sb 2 Te 5 films with a considerable c... more Switching and memory effects in as-deposited amorphous Ge 2 Sb 2 Te 5 films with a considerable concentration of crystalline nuclei have been investigated. Variation of the phase composition of the sample has been confirmed by Raman spectroscopy data. The influence of nuclei on parameters of the current voltage characteristic has been studied. Significant variation of initial resistance and threshold voltage due to a different nuclei configuration has been observed. In some cases the current voltage characteristic was monotonous i.e. the intrinsic S-shape of the current-voltage characteristic disappeared and memory recording occurred without prior switching. The measurements were made in a current controlled mode which allowed conducting a thorough investigation of switching and current filament formation.

Semiconductors

It is demonstrated that As2Se3:Bix films deposited by thermal evaporation have p-type impurity co... more It is demonstrated that As2Se3:Bix films deposited by thermal evaporation have p-type impurity conductivity, whereas films of the same composition, produced by ion-plasma cosputtering in vacuum exhibit n-type impurity conductivity. On the basis of these results, a new method is suggested for the fabrication of p-n homojunctions in film structures made of chalcogenide glassy semiconductors doped with bismuth in various ways.

Journal of Non-Crystalline Solids

Chemical Journal of Kazakhstan

Among alternative sources of energy, such as solar, wind, and hydrogen energy, biofuel occupies a... more Among alternative sources of energy, such as solar, wind, and hydrogen energy, biofuel occupies a special place because it has a few useful properties. Compared to the current price of gasoline,the price of biofuel is very low. During its use, biofuel releases less greenhouse gases into the environment and is less flammable. However, in order to support biofuel, it is necessary to purify its composition from unnecessary glycerol, methanol, and free fatty acids. Free fatty acids in biofuel are flammable and pollute car engines. Various ionic liquids have been developed for the purification of biofuel. One of them is 1-butyl-3-methylimidazolium dicyanamide. The purpose of this work is to study the state of purification of free fatty acids in biofuel by 1-butyl-3-methylimidazolium dicyanamide at the molecular level using chemical quantum calculations. Methodology. HyperChem PM3 method was used for quantum chemical calculations of chemical structures, molecular electrostatic potentials,...

Polymers

In this study, the mechano-chemical properties of aromatic polymer polyetheretherketone (PEEK) sa... more In this study, the mechano-chemical properties of aromatic polymer polyetheretherketone (PEEK) samples, irradiated by high energy electrons at 200 and 400 kGy doses, were investigated by Nanoindentation, Brillouin light scattering spectroscopy and Fourier-transform infrared spectroscopy (FTIR). Irradiating electrons penetrated down to a 5 mm depth inside the polymer, as shown numerically by the monte CArlo SImulation of electroN trajectory in sOlids (CASINO) method. The irradiation of PEEK samples at 200 kGy caused the enhancement of surface roughness by almost threefold. However, an increase in the irradiation dose to 400 kGy led to a decrease in the surface roughness of the sample. Most likely, this was due to the processes of erosion and melting of the sample surface induced by high dosage irradiation. It was found that electron irradiation led to a decrease of the elastic constant C11, as well as a slight decrease in the sample’s hardness, while the Young’s elastic modulus decre...

In our work, we have studied the formation of choline chloride based NADESs using DFT calculation... more In our work, we have studied the formation of choline chloride based NADESs using DFT calculations, and all-atom classical Molecular Dynamics (MD) simulations. In our DFT calculations, the ground state geometry optimizations were performed in the gas phase using DFT B3LYP 6-31+G(d) level of theory. Moreover, all-atom classical Molecular Dynamics simulations were implemented using Gromos force eld. The DFT calculation results revealed the formation of NADESs via formation (creation) of binding between chlorine and choline, and chlorine and glucose. Next, the results of all-atom classical Molecular Dynamics simulations, based on the time average of the equilibrated production run of MD simulations, stated that the nitrogen atom of choline ion, and chloride ion have greater interactions, while chloride ion have also greater interaction with glucose during formation of NADES. Highlights Intermolecular interactions of NADES were studied by DFT calculations and all-atom classical Molecular Dynamics simulations.

Effects of electron-beam processing on the structure and mechanical properties of poly-ether-ethe... more Effects of electron-beam processing on the structure and mechanical properties of poly-ether-ether ketone (PEEK) were studied by XRD and tribological tests. An ambiguous change in the mechanical properties of the irradiated samples was found. In particular, the wear rate of sample 1 is higher than that of the unirradiated original sample, while it is lower for samples 2-7. Sample 4 had the lowest wear rate, and most likely the changes in the mechanical properties of the samples were due to the transformation of their amorphous component. Comparison of the X-ray spectra of the irradiated and unirradiated samples did not reveal any differences in their crystal structure.

Membranes

In this paper, we demonstrate a new, highly efficient method of crosslinking multilayer graphene,... more In this paper, we demonstrate a new, highly efficient method of crosslinking multilayer graphene, and create nanopores in it by its irradiation with low-energy argon cluster ions. Irradiation was performed by argon cluster ions with an acceleration energy E ≈ 30 keV, and total fluence of argon cluster ions ranging from 1 × 109 to 1 × 1014 ions/cm2. The results of the bombardment were observed by the direct examination of traces of argon-cluster penetration in multilayer graphene, using high-resolution transmission electron microscopy. Further image processing revealed an average pore diameter of approximately 3 nm, with the predominant size corresponding to 2 nm. We anticipate that a controlled cross-linking process in multilayer graphene can be achieved by appropriately varying irradiation energy, dose, and type of clusters. We believe that this method is very promising for modulating the properties of multilayer graphene, and opens new possibilities for creating three-dimensional ...

Journal of information and communication convergence engineering, 2011

The absence of deep traps for electrons in the spectrum of As 40 Se 30 S 30 localized states film... more The absence of deep traps for electrons in the spectrum of As 40 Se 30 S 30 localized states films obtained by ion sputtering was determined. Bipolar drift of charge carriers was found in amorphous As 40 Se 30 S 30 films of chalcogenide glassy semiconductors, obtained by ion-plasma sputtering of high-frequency, unlike the films of these materials obtained by thermal evaporation.

Journal of Non-Crystalline Solids, 2012

Switching and memory effects in as-deposited amorphous Ge 2 Sb 2 Te 5 films with a considerable c... more Switching and memory effects in as-deposited amorphous Ge 2 Sb 2 Te 5 films with a considerable concentration of crystalline nuclei have been investigated. Variation of the phase composition of the sample has been confirmed by Raman spectroscopy data. The influence of nuclei on parameters of the current voltage characteristic has been studied. Significant variation of initial resistance and threshold voltage due to a different nuclei configuration has been observed. In some cases the current voltage characteristic was monotonous i.e. the intrinsic S-shape of the current-voltage characteristic disappeared and memory recording occurred without prior switching. The measurements were made in a current controlled mode which allowed conducting a thorough investigation of switching and current filament formation.

Semiconductors

It is demonstrated that As2Se3:Bix films deposited by thermal evaporation have p-type impurity co... more It is demonstrated that As2Se3:Bix films deposited by thermal evaporation have p-type impurity conductivity, whereas films of the same composition, produced by ion-plasma cosputtering in vacuum exhibit n-type impurity conductivity. On the basis of these results, a new method is suggested for the fabrication of p-n homojunctions in film structures made of chalcogenide glassy semiconductors doped with bismuth in various ways.