scholarly journals Investigation of electrical conductivity of graphene-contained shungite using the high-resolution scanning electron microscopy.

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
I.V. Antonets ◽  
◽  
E.A. Golubev ◽  
V.G. Shavrov ◽  
V.I. Shcheglov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Specific Resistance ◽  
Specific Conductivity ◽  
Relative Concentration ◽  
Carbon Distribution ◽  
Black And White ◽  
Current Flows ◽  
Carbon Component ◽  
Scanning Electron

The electrical conductivity of carbon component of graphene-contained shungite is investigated. The basis of this investigation is the statistic processing of carbon distribution cards which are obtained by high-resolution scanning electron microscopy. For the original card of carbon distribution it is proposed the method of building of contour card with following conversion its into binary card which consist of net from cells having black and white colours. The statistic analysis of repeating of binary card structure in the frame of selected region having square form. It is shown that the relative concentration of cells both colour in selected region by the increasing of its dimensions undertakes the scattering which increases when dimension of region is decreased. It is found the minimal dimension of region in which the deflection of relative concentration of cells of unit colour from the constant value of this concentration is not more then 20%. This dimension is received as flat-characteristic of middle-statistic block which relative properties repeats the relative properties of structure as a whole. From the conditions of isotropy of carbon component of shungite the space model of symmetrical along three axis cubic middle-statistic block which consist of cubic cells both colours. It is established that black cells correspond to large conductivity and white cells correspond to small conductivity. In connection with the direction of electric current which flows along the flat of card it is proposed two kinds of graphene packets orientation. In this case the black cells having large conductivity are identified with graphene packets where the current flows along the graphene slides and the white cells having small conductivity are identified with graphene packets where the current flows across the graphene slides. For the analysis of conductivity of middle-statistic block the model of current tubes is proposed. From the whole structure of block the two kinds of tubes are selected. This kinds of tubes correspond to different cases of alternate with each other black and white cells. The structure of these tubes is identified with the set of favourable and non-favourable oriented graphene packets. On the basis of known resistances of graphene slide it is calculated the resistances of packets having favourable and non-favourable orientations. Using this resistances of packets the resistances of tubes are calculated. It is shown that the main role in resistance of tubes formation plays the resistance of intervals between graphene slides and graphene packets. Using obtained resistances of tubes it is found the resistance of middle-statistic block which has the parallel connections of tubes. On the basis of middle-statistic block resistance it is found the specific resistance and the back proportional to this resistance the specific conductivity of carbon component of shungite. It is shown that the main parameter which determines the resistance and conductivity is the specific resistance of interval between graphene slides and graphene packets. It is execute the comparison of determined specific conductivity with the observed in experiments specific conductivities of shungite received from different natural deposits. The some practical remarks and some little defects are proposed. The possibilities of improvement of proposed model are discussed.

scholarly journals Application of decomposition method for calculation of electrical conductivity of shungite based on the electron-microscopic cards of carbon distribution.

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
I.V. Antonets ◽  
◽  
E.A. Golubev ◽  
V.G. Shavrov ◽  
V.I. Shcheglov ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Specific Resistance ◽  
Specific Conductivity ◽  
Specific Electrical Conductivity ◽  
Contact Method ◽  
Carbon Distribution ◽  
Conducting Phase ◽  
Flat Area ◽  
Black And White ◽  
Shungite Carbon

The outlook of using the shungite for covering large area which can protect something from electromagnetic radiation is described. As a main parameter which determines the efficiency of created screens is determined the specific electrical conductivity of shungite carbon. For the measuring of conductivity it is proposed to use the high-resolution raster electron microscopy which make be possible to obtain the card of carbon distribution in the scale of some nanometers. The method of binarization of this card is proposed. This binare card describes the spatial distribution of two phases – large-conducting and small-conducting. The large-conducting phase consist of graphene slides. The small-conducting phase consist of chaotic distributed atoms of carbon. On the basis of binare card it is constructed the flat-area block which is looked as net from square cells having two colours – black and white which correspond one by one to large and small-conducting phases. On the area of block it is selected tubes of current which consist of straight chains of black and white cells connected in succession. The whole resistance of block is determined by parallel connection of these tubes. It is proposed the procedure of constructing this symmetrical block along two coordinates. The scheme of this construction is proposed. The calculation of block resistivity along two coordinates is executed. On the basis of flat-area block it is constructed the space elementary block which has equal to each other resistance along three coordinates. For the determination of specific resistance of material as a whole it is carried out the procedure of decomposition which consist of presentation the unit volume of specimen as a set of elementary blocks. For the real specimens of shungite from two natural deposits it is made the calculation of specific resistance and specific conductivity of shungite carbon. It is established that the calculated data are coincide with data received by contact method in the accuracy of 30%. As a most advantage of proposed method it is established the possibility of conductivity measuring of carbon part of shungite in the scale of some units of nanometers.

scholarly journals Application of independent-channel method for investigation of electrical conductivity of graphene-containing shungite.

2021 ◽  
Author(s):  
I.V. Antonets ◽  
◽  
E.A. Golubev ◽  
V.G. Shavrob ◽  
V.I. Shcheglov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Spatial Distribution ◽  
Current Flow ◽  
Specific Conductivity ◽  
Specific Electrical Conductivity ◽  
Parallel Connection ◽  
Raster Electron Microscopy ◽  
Current Flows

The independent channel method which is intended for the calculation of specific electrical conductivity of graphene-contained shungite is proposed and realized on practice. It is noted that the most important of shungite application is the creation of screen hawing large area which are able to block electromagnetic radiation in wide frequency range. The most important factor which determines the blocking properties of shungite is the specific electrical conductivity of its carbon part which is determined by the spatial distribution of carbon atoms. As a main method of carbon structure investigation is mentioned the high-resolution raster electron microscopy which allows from the surface of specimen to receive the card of distribution of graphene slides and graphene packets. The spatial factor which determines the shungite conductivity is large anisotropy of single graphene slide which reaches three orders and more in the cases along and across the slide. The proposed method independent channels takes into consideration the arbitrary orientation of graphene packets relatively to direction of current flow. As a basis of method is employing the card of carbon spatial distribution which is received by raster electron microscopy method. The card is divided by parallel channels which transverse dimension is near or slightly exceeds the typical dimension of graphene packet. The channels are divided to square blocks which sides are equal to width of channel. The whole resistance of channel is formed by the successive connection of individual resistances of blocks. The resistance of whole card is determined by parallel connection of channels or averaging of resistance of all channels and following filling the whole area of card. The first step of analysis is the determination of advantage orientation of slides inside of every blocks. On the basis of determined orientation the block is filled by periodic structure which period is equal to the width of graphene slide and neighbouring interval. As a parameter which determines the orientation is used the angle between advantage orientation of graphene slides and axis of current flow between contacts. Owing to symmetry of task in comparison of current direction the limited meanings of corner is 0 and 90 degree. It is established two principal different cases of orientation: first – when determining angle is less than 45 degree and second when this angle is more than 45 degree. In the first case the current flows along the stripe with large conductivity. In the second case the current flows across these stripes so as through the stripes with low conductivity. It is found the smooth dependence of block resistivity from the angle of strip orientation. For the characteristic of area which is filled graphene slides it is proposed the coefficient of filling which is determined by binary discretization method. On the basis of analysis of slides orientation and filling coefficients are calculated the resistance of individual blocks. The resistances of all channels of investigated card are proposed. By using two methods – parallel connection and averaging over all channels it is calculated the specific electrical resistance and specific electrical conductivity of material as a whole. It is found that the received values of specific conductivity exceed the determined in experiment value in several (to 10) times. For the coordination of calculated value with experimental value it is made the variation of specific resistances of graphene slides and intervals between its. It id found that the calculation by method of parallel connection of channels ensures several better coordination than method of averaging. It is shown that the resistance is improved in the first turn by the increasing the resistance of interval between slides. In the quality of possible reason of decisive role of interval it is proposed the observed in experiment sharp non-homogeneity of relative arrangement of graphene slides. It is discussed the possible courses of further development of work. As a most important task it is proposed the more circumstantial determination of statistical character of received results.

USE OF NANOFLUIDS BASED ON CARBON NANOPARTICLES TO DISPLACE OIL FROM THE POROUS MEDIUM MODEL

2020 ◽  
Vol 6 (4) ◽  
pp. 141-157
Author(s):  
Yuri V. Pakharukov ◽  
Farid K. Shabiev ◽  
Ruslan F. Safargaliev ◽  
Boris S. Yezdin ◽  
Valery V. Kalyada
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Porous Medium ◽  
Synergistic Effect ◽  
Transition Region ◽  
Dimensional Structure ◽  
Hybrid Nanofluids ◽  
Scanning Electron

Graphene, due to its two-dimensional structure, has some unique properties. For example, the thermal conductivity and electrical conductivity of graphene are an order of magnitude higher than the thermal conductivity and electrical conductivity of copper. For this reason, graphene-based nanofluids are now used in many industries. Due to the effect of self-organization of graphene nanoparticles with hydrocarbon molecules, the use of graphene has become possible in the oil industry. Graphene-based nanofluids are used as a displacement fluid to increase the oil recovery coefficient. The displacing ability of graphene-based nanofluids is concentration dependent. An increase in the concentration of nanoparticles entails an increase in viscosity, which negatively affects the performance characteristics of the nanofluid. This problem is partially solved due to the synergistic effect, hybrid nanofluids consisting of nanoparticles of graphene and metals or carbides enhance the displacing ability. Using atomic force microscopy, scanning electron microscopy and molecular modelling methods, this work has studied the formation of supramolecular structures that form a transition region at the oil-nanofluid interface with low surface tension as a result of a synergistic effect in the interaction of graphene planar nanoparticles and silicon carbide nanoparticles covered with graphene layers (Core-shell). The model experiments on a Hele-Shaw cell have shown that in a porous medium, such hybrid nanofluids have a high displacement ability of residual oil. At the same time, the oil — nanofluid interface remains stable, without the formation of viscous fingers. During the study by scanning electron microscopy, a transition region was observed, in the structuring of which the nanoparticles were directly involved. The displacement efficiency of a hybrid nonofluid depends on the concentration of nanoparticles and their interaction.

Structural and electrical investigation of (Ag3AsS3)x(As2S3)1−x superionic glasses

Open Physics ◽  
2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Ihor Studenyak ◽  
Yuriy Neimet ◽  
Csaba Cserháti ◽  
Sándor Kökényesi ◽  
Edvardas Kazakevičius ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Activation Energy ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Transmission Coefficient ◽  
Structural Studies ◽  
Compositional Range ◽  
Electrical Investigation ◽  
Scanning Electron

AbstractStructural studies of (Ag3AsS3)x (As2S3)1−x chalcogenide superionic glasses in the compositional range x = 0.3–0.9 were performed by scanning electron microscopy. Temperature and compositional dependences of transmission coefficient, electrical conductivity, and activation energy were investigated

Effect of Al2O3 on the Electrical Conductivity and Structural Study in MgI2-Mg3(PO4)2 Based Solid Electrolyte

2013 ◽  
Vol 701 ◽  
pp. 150-153
Author(s):  
A. Aziz ◽  
M.M. Mahat ◽  
A.H. Ahmad
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Impedance Spectroscopy ◽  
Field Emission ◽  
Weight Percent ◽  
Binary Compound ◽  
Maximum Conductivity ◽  
Enhanced Conductivity ◽  
Scanning Electron

The effect of filler to the binary compound of Magnesium Iodide ( MgI2) and Magnesium Phosphate (Mg3(PO4)2is investigated. A small amount Alumina (Al2O3) filler in the range of 2-10 weight percent is added to the optimum composition with maximum conductivity of binary compound 0.7 Mg3(PO4)2and 0.3 MgI2.The electrical conductivity of theMgI2- Mg3(PO4)2- Al2O3measured using the impedance spectroscopy (IS) method and result shows that the electrical conductivity of the compound has improved up to 9.84x10-4Scm-1. Field Emission Scanning Electron Microscopy (FESEM) images show some changes in the morphology after introduce the filler. The samples with filler showsnano flakes like structure with some space createdallowing the Mg2+cations to migrate that lead to enhanced conductivity.

Preparation of Polyaniline @ Polypyrrole Conductive Composite via In Situ Polymerization

2013 ◽  
Vol 562-565 ◽  
pp. 1137-1142
Author(s):  
Hui Xia Feng ◽  
Bing Wang ◽  
Lin Tan ◽  
Na Li Chen
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
In Situ Polymerization ◽  
Conductive Composite ◽  
The Core ◽  
Novel Method ◽  
Scanning Electron

We prepared the polyaniline@polypyrrole (PAn@PPy) conductive composite by a novel method. The struction like Pre-prepared PAn as the core and PPy as the shell for the composite has been prepared by in-situ polymerization. The PAn@PPy conductive composite presents an electrical conductivity of 12.5 S/cm, which is much higher than pure PAn. The synthesized polymer composites are characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Thermogravimetric analysis (TG). The results indicated that PPy successfully grafted on PAn and the heat resistance of nanocomposite is remarkably increased.

Scanning Electron Microscopy of soft-bodied tephritid larvae

1990 ◽  
Vol 48 (3) ◽  
pp. 490-490
Author(s):  
R. Paul ◽  
V. C. Kapoor
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Microscope ◽  
Deionized Water ◽  
Soft Body ◽  
Black And White ◽  
Critical Point Drying ◽  
White Film ◽  
Ethanol Series ◽  
Scanning Electron

The soft body of dipteran larva has been posing a difficulty for entomologist to go for scanning electron microscopy. Dehydration by the conventional methods results in crumpling of the larval integument thereby distorting the minute details. The cuticle is impermeable to various types of fixatives and its puncturing with needle causes severe distortion of structure due to haemoiymphloss. To avoid this a new method was developed to prepare specimen for scanning electron microscopy. The specimen was kept in doubled is tilled deionized water at 60°C for half an hour before further treatment. It was sonicated in mild detergent (Sodium bicarbonate) for 30 sec. It was again washed with deionized water and specimen was placed in modified super skiper's solution (Grodowitz et al., 1982) and then rinsed twice in Carl's solution, after dehydration through ethanol series, critical point drying was done. Specimen was coated with gold pulludium and photographed by using JEM - 1200 EX (Jeol) electron microscope and Indu Panchromatic 125 ASA black and white film.

Multiwall Carbon Nanotube / Polyvinyl Alcohol Nanofibers Film, Electrical Conductivity Improvement

2020 ◽  
Vol 38 (3A) ◽  
pp. 431-439
Author(s):  
Akram R. Jabur
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Polyvinyl Alcohol ◽  
Maximum Stress ◽  
Conductive Polymer ◽  
Multiwall Carbon Nanotube ◽  
Multiwalled Carbon ◽  
Electrospinning Technique ◽  
Multiwall Carbon ◽  
Scanning Electron

Conductive polymer films were prepared of polyvinyl alcohol (PVA) with (0, 2, 4, 6, 8, and 10) wt. % multiwalled carbon nanotubes (MWCNTs) by electrospinning technique. The morphologies of the synthesized films were tested by scanning electron microscopy (SEM). Average fiber diameters gauged statically was (115nm) for (PVA/10 wt. % MWCNT film) while (170nm) for pure PVA electro spun film. Electrical conductivity (EC) of Polymeric nanofiber films improve by increasing MWCNT addition concentration from (3.69 × 10-7 S/ cm) for the pure (PVA) film to (1.24 ×10-2 S/cm) for the film with 10 wt. % MWCNT. The maximum stress of PVA film were increased by adding MWCNTs concentration, the modulus of elasticity was enhanced from 12.87 MPa for pure PVA to 49.89 MPa for PVA/8wt% MWCNT.

scholarly journals Synthesis, Crystal Structure Refinement, and Electrical Conductivity of Pb(8−x)Na2Smx(VO4)6O(x/2)

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Tatiana M. Savankova ◽  
Lev G. Akselrud ◽  
Lyudmyla I. Ardanova ◽  
Alexey V. Ignatov ◽  
Eugeni I. Get’man ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Solid Solutions ◽  
Structure Refinement ◽  
Crystal Structure Refinement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Solid solutions of Pb(8−x)Na2Smx(VO4)6O(x/2)were studied using X-ray diffraction analysis including Rietveld refinement and scanning electron microscopy and by measuring their electrical conductivity. Crystal structure of the solid solutions was refined and the solubility region0≤x≤0.2was determined for samarium substitution for lead under the scheme2Pb2++□→2Sm3++O2-. The influence of degree of substitution on the electrical conductivity of solid solutions was established.

Optimization of Deposition Conditions for CNTs/Carbon Fiber Hybrid Multiscale Composites via Taguchi Method

2010 ◽  
Vol 123-125 ◽  
pp. 1179-1182 ◽  
Author(s):  
Yi Qi Wang ◽  
Hyoun Kon Ku ◽  
Joon Hyung Byun ◽  
Jung I. Song
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Carbon Fiber ◽  
Taguchi Method ◽  
Carbon Fabric ◽  
Signal To Noise ◽  
Statistical Software ◽  
Multiscale Composites ◽  
Scanning Electron ◽  
Deposition Conditions

Electrophoretic deposition (EPD) technique was applied to deposit carbon nanotubes on a carbon fabric. Optimization of EPD conditions was investigated to improve electrical conductivity for CNTs/carbon fiber hybrid multiscale composites by Taguchi method. Based on design of experiment, a L9(3)4 orthogonal array was chosen to conduct experiments. Due to the electrical conductivity of composites increased with the increasing content of CNTs in composites, it was selected as the response on the analysis of the means (ANOM) and the signal to noise (S/N) ratio. In addition, scanning electron microscopy (SEM) was utilized to examine the distribution of CNTs on the surface of a carbon fabric. The statistical software MINITAB 14 was utilized to determine the optimal deposition conditions.

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