Electrical Transport Research Articles

Data-driven Simulation of Effects of a Solar Flare with Extreme-ultraviolet Late Phase on Ionospheric Electron Density

Effects of the extreme-ultraviolet (EUV) late phase of solar flares on the ionosphere were rarely studied. Here we simulated such effects on the ionospheric electron density using an ionosphere−thermosphere coupled model driven by the realistic solar spectrum observed during the X1.8 flare on 2012 October 23. Global total electron content (TEC) observations and simulations showed that the dayside ionospheric TEC during the EUV late phase increased more than that of the flare’s main phase. We examined the performance of the model for flares with EUV late phase. The results showed that the F-region electron density enhancement and recovery did not vary in the same pace as the temporal variations of the EUV late phase, and the presence of the EUV late phase prolonged the recovery of electron density by ∼9 hr. We also found that the enhancement in electron density was mainly determined by the chemical production, while the recovery of electron density was primarily controlled by the electric field transport effects. This study enhanced understanding of the intricate physical and photochemical processes governing Earth’s space environment and similar planetary systems during solar flare events with EUV late phase.

Synthesis of high-quality large Cr2TiC2T MXene monolayers, their mechanical properties, p-type electrical transport, and positive photoresponse

Synthesis of high-quality large Cr2TiC2T MXene monolayers, their mechanical properties, p-type electrical transport, and positive photoresponse

Optimization of carrier mobility in Pr-doped SrTiO3 thin films through controlled Sr-segregation for optoelectronic applications

Functional oxides employed in electronic components hold significant promise for future electronic devices. Strontium titanate based thin films have several emergent features due to unsaturated bonds, dimension restriction, production of oxygen vacancies and point defects that make them attractive for optoelectronic applications. Here we prepared Pr-doped strontium titanate thin films via RF magnetron sputtering in a pure Argon environment at various gas pressures followed by heat treatment. The structural parameters, analyzed via XRD and Raman spectroscopy, were correlated with the electrical transport properties. Intriguing morphological features such as Stranski–Krastanov (SK) growth and cation segregation observed by FESEM and AFM analysis were further examined to elucidate the conduction mechanism in the films. The optical studies unveiled significant transparency in the visible spectrum. Photoluminescence emission studies at specific wavelengths shed light on the involvement of oxygen vacancies. By carefully controlling annealing conditions and optimizing sputtering parameters, thin films devoid of Sr segregation with highest reported carrier mobility of 33.9 cm2/V s were prepared. The high mobility leading to enhanced conductivity render the films suitable for a wide range of optoelectronic applications.

Analysis of hub parameters in fuzzy hypergraphs extending to intuitionistic fuzzy threshold hypergraphs: Applications in designing transport networks in amusement parks using hub hyperpaths

A hypergraph is a generalization of a graph where an edge can connect any number of vertices. In this paper, many different aspects of fuzzy hypergraphs and their applications are examined. The concepts of the hub hyperpath, hub set, and hub number of fuzzy hypergraphs are defined and analyzed. Specifically, the hub number in complete fuzzy hypergraphs has been analyzed and provided an example as an application part in transportation systems. Furthermore, these concepts have been expanded to Intuitionistic Fuzzy Hypergraphs (IFHGs), defining the hub hyperpath, hub set, and hub number. Additionally, the problem of designing an efficient electric transport system for moving between game stations in a large amusement park has been investigated using hub analysis within the framework of an Intuitionistic Fuzzy Threshold Hypergraph (IFTHG) environment.

Optimizing Sustainable Urban Mobility: Integration Of Electric Vehicle Charging Infrastructure Into Smart Buildings

The integration of electric vehicle (EV) charging infrastructure into smart buildings is a crucial step toward enhancing sustainable urban mobility. This paper explores the benefits, challenges, strategies, and best practices associated with this integration, with a focus on optimizing EV charging accessibility and promoting a cleaner transportation ecosystem. Traditional vehicles powered by fossil fuels contribute significantly to pollution and greenhouse gas emissions, highlighting the urgent need for sustainable alternatives. EVs offer reduced emissions, lower operating costs, and potential energy independence through renewable sources, making them a promising solution for urban mobility challenges. Despite these advantages, the widespread adoption of EVs faces hurdles, particularly regarding charging infrastructure availability and accessibility in urban areas. Range anxiety among EV users due to insufficient charging stations is a significant concern hindering the transition to electric transportation. The paper emphasizes strategic placement of charging stations, integration with renewable energy sources like solar panels, and utilization of smart grid technologies to optimize EV charging operations. Case studies such as Tesla Gigafactory Shanghai and Googleplex showcase successful implementations, demonstrating scalability, user-centric design, and seamless integration with building management systems. Key challenges such as funding constraints, technical interoperability, and grid integration are addressed, proposing solutions like innovative financing models, standardization efforts, and advanced grid management technologies. By addressing these challenges and implementing sustainable solutions, the integration of EV charging infrastructure into smart buildings can significantly contribute to reducing environmental impact, promoting cleaner transportation options, and fostering a more sustainable and resilient urban environment

Critical current density and AC magnetic susceptibility of high-quality FeTe0.5Se0.5 superconducting tapes

Iron telluride-selenium superconducting materials, known for their non-toxicity, ease of preparation, simple structure, and high upper critical fields, have attracted much research interest in practical application. In this work, we conducted electrical transport measurements, magneto-optical imaging, and AC magnetic susceptibility measurements on FeTe0.5Se0.5 superconducting long tapes fabricated via reel-to-reel pulsed laser deposition. Our transport measurements revealed a high critical current density that remains relatively stable even with increasing external magnetic fields, reaching over 1 × 105 A/cm2 at 8 K and 9 T. The calculated pinning force density indicates that normal point pinning is the primary mechanism in these tapes. The magneto-optical images demonstrated that the tapes show homogeneous superconductivity and uniform distribution of critical current density. The AC magnetic susceptibility measurements also confirmed their strong flux pinning nature of withstanding high magnetic field. Based on these characteristics, FeTe0.5Se0.5 superconducting tapes show promising prospects for applications under high magnetic field.

Development and Characterization of Ethylene‐Vinyl Acetate‐Graphene Nanocomposites

AbstractThe prospective applications of carbon graphene nanoplatelets (GNPs) reinforced ethylene vinyl acetate (EVA) nanocomposites in flexible electronics, energy storage devices, and thermal management systems have attracted a lot of attention. These nanocomposites offer an effective solution for enhancing the electrical conductivity of interfacing materials in electronic systems and addressing issues related to thermal management. GNPs that possess excellent thermal conductivity of 2000–4000 W m−1 K−1 and an electrical conductivity of 107 S m−1 are utilized in this investigation. The homogeneous dispersion of nanofiller and the effective load transfer between components through strong filler/polymer interfacial interactions are essential for the creation of multifunctional polymer nanocomposites. Particularly, their electrical conductivity and dielectric properties are highlighted in this study, with an emphasis on the synthesis and characterization of nanocomposite materials. This work investigates the utilization of graphene nanocomposites in EVA using a melt‐mixing technique assisted by sonication to fabricate multifunctional composites. Incorporating different weight percentages of GNPs (ranging from 0.1 to 0.4 wt.%) within the polymer matrix is carried out. In the present study, the nanocomposites are characterized by scanning electron microscopy investigation and impedance spectrum analysis. The distinctive characteristics of the AC electrical transport in nanocomposites are investigated between 10 Hz and 1 MHz. Excellent interfacial compatibility has been demonstrated by the homogenous distribution of GNPs within the matrix, confirmed by SEM examination. These EVA nanocomposites demonstrate improved electrical conductivity, thereby rendering them very useful for energy storage applications, such as electronic capacitors, wherein supports with a significant dielectric constant and minimal dielectric loss are required.

Electrical transport properties of topographically demorphed films of La1-xBaxMnO3 grown on (00l)-oriented LaAlO3 substrate via spin-coating method

Herein, the crystal structure, valence, and electrical transport properties of La1-xBaxMnO3 films were examined by preparing La1-xBaxMnO3 films with varying Ba content (x = 0.22, 0.24, 0.26, 0.28) on LaAlO3 substrates using the sol-gel spin coating technique. The La1-xBaxMnO3 films prepared in the study exhibit topographically demorphed and non-dense characteristics in the microstructure, which is mainly caused by the Volmer-Weber growth mode of the films and the volatilization of organic matter during the sol-gel sintering process for films preparation. The increase of Ba doping leads to MnO6 deformation, decrease in grain boundary scattering, increase in Mn4+ ion content, and enhancement of both the double exchange mechanism and the Jahn-Teller effect. The four-probe results showed that the peak resistivity of the films decreased significantly with the increase in Ba2+ doping, and the metal-insulator transition temperature (Tp) shifted to higher temperatures. Peak temperature coefficient of resistivity (TCR) corresponding temperature (Tk) increased from 283.05 K (x = 0.22) to 309.31 K (x = 0.28), which was consistent with the trend of Tp; the peak value of TCR decreased with the increase of Ba doping. When x = 0.24, the Tk of the La1-xBaxMnO3 films reach room temperature (294.25 K) with TCR = 9.01 % K−1. In conclusion, the electrical properties of La1-xBaxMnO3 can be optimized by varying the amount of Ba doping to obtain La1-xBaxMnO3 films with room-temperature Tk and higher TCR values, providing reasonable data support and theoretical explanation for the Ba doping mechanism.

Theoretical design of molecular diode based on thiol- and amino- terminated molecules

Utilizing density functional theory (DFT) and non-equilibrium Green’s function, we systematically studied the electrical transport and rectification properties of thiol- and amino-terminated molecules embedded in graphene nanoribbons. We firstly found the thiol-terminated molecules show better electron transport properties compared to the amino-terminated, which can be attributed to the strong electronwithdrawing ability and favorable coupling effects. Secondly, the symmetrical molecules show almost symmetrical current-voltage (I-V) curves and exhibit negligible rectification effects. On the other hand, the asymmetrical molecules exhibit asymmetrical I-V curves and better rectification performance. The rectification effect is closely related to molecular asymmetry degrees. For example, the rectification ratio of asymmetric N6 ((E)-Nl-(3-aminopropyl)-but-2-ene-1,4-diamine) molecule is much smaller than the N4 (5-phenylthiazole-2,4-diamine) and N5 (2,6-diaminohexane-1,1,5-triol) molecules. Furthermore, we found the rectification ratio of the asymmetrical amino-terminated molecules can reach 400, while the biggest rectification ratio of the thiol-terminated molecule can only reach 45. These findings offer crucial insights for future graphene molecular electronic device design.

Разработка комплексного показателя оценки состояния городского электротранспорта для органов исполнительной власти Российской Федерации

This article analyzes 115 cities on the territory of the Russian Federation in which one or more urban electric transport systems operate. It is determined that in the modern industry there is no single comprehensive indicator of the state of urban electric transport, which would allow an assessment of the state of systems not only in relation to their own indicators of previous years, but also in relation to other, similar systems. A comprehensive indicator is proposed that will allow a comprehensive assessment of the state of urban electric transport and interpret it in numerical terms for its application by state and regional authorities, allowing to quickly draw conclusions and make a decision on further adjustment of the functioning of the electric transport system, characterized by a relatively simple formula for calculation and does not require specific competencies for those conducting the analysis. The key indicators of urban electric transport are systematized, including those related to the operated energy infrastructure, linear infrastructure, park facilities, including technical buildings and structures for system maintenance, indicators related to rolling stock and its key technical characteristics, as well as the availability of urban electric transport for residents of the considered locality and passenger flows within this framework systems. The boundaries of the values of the final indicator have been determined, within which the state of urban electric transport will be assessed by state and regional authorities as satisfactory or unsatisfactory and requiring decisions on revising approaches to the development of the system within the framework of strategic transport planning documents.

Nanoscale Electron Beam Patterning of PEDOT:PSS Free‐Standing Films for Enhanced Thermoelectric Performance

The growing demand for flexible, lightweight, and highly processable electronic devices makes high‐functionality conducting polymers such as poly (3,4‐ethylene dioxythiophene): polystyrene sulfonate (PEDOT:PSS) an attractive alternative to conventional inorganic materials for various applications including thermoelectrics. However, considerable improvements are necessary to make conducting polymers a commercially viable choice for thermoelectric applications. This study explores nanopatterning as an effective and unique strategy for enhancing polymer functionality to optimize thermoelectric parameters, such as electrical conductivity, Seebeck coefficient, and thermal conductivity. Introducing nanopatterning into thermoelectric polymers is challenging due to intricate technical hurdles and the necessity for individually manipulating the interdependent thermoelectric parameters. Here, array nanopatterns with different pattern spacings are imposed on free‐standing PEDOT:PSS films using direct electron beam irradiation, thereby achieving selective control of electrical and thermal transport in PEDOT:PSS. Electron beam irradiation transformed PEDOT:PSS from a highly ordered quinoid to an amorphous benzoid structure. Optimized pattern spacing resulted in a remarkable 70% reduction in thermal conductivity and a 60% increase in thermoelectric figure of merit compared to non‐patterned PEDOT:PSS. The proposed nanopatterning methodology demonstrates a skillful approach to precisely manipulate the thermoelectric parameters, thereby improving the thermoelectric performance of conducting polymers, and promising utilization in cutting‐edge electronic applications.

ANALYSIS AND ASSESSMENT OF AIR QUALITY IN ASTANA: COMPARISON OF POLLUTANT LEVELS AND THEIR IMPACT ON HEALTH

This study presents an in-depth analysis of air quality in Astana, Kazakhstan, utilizing both mobile and stationary air monitoring systems over a two-year period. The research focuses on tracking key air pollutants, namely carbon monoxide (CO), nitrogen dioxide (NO₂), particulate matter (PM2.5 and PM10), and sulfur dioxide (SO₂), providing a comparative assessment of seasonal trends and the sources of pollution, which include transportation, industrial emissions, and domestic heating during the cold season. The study emphasizes the significance of monitoring systems in urban environments to understand better the impact of air pollution on public health and the effectiveness of sustainable interventions. One of the major insights from this research is the comparison between seasonal variations in pollutant levels and the city's transition toward sustainable energy practices, such as increased gasification and the use of electric transportation, which has already demonstrated a positive impact on reducing emissions during peak heating periods. The results show that while Astana has improved air quality, air pollution remains a concern, especially in winter due to the increased use of solid fuel. This paper emphasizes the importance of real-time data from mobile sensors and suggests their wider use to complement stationary sensors for better monitoring. In addition to pollutant tracking, the study delves into the health implications of prolonged exposure to air pollutants, particularly in urban areas. The study concludes by advocating for expanded use of mobile monitoring systems and advanced data analytics to provide actionable insights for policymakers, urban planners, and public health officials.

Robustly Boosting Thermoelectric Performance of N-Type PbSe via Lattice Plainification and Dynamic Doping.

Ideal thermoelectrics shall possess a high average ZT, which relies on high carrier mobility and appropriate carrier density at operating temperature. However, conventional doping usually results in a temperature-independent carrier concentration, making performance optimization over a wide temperature range be challenging. This work demonstrates the combination of lattice plainification and dynamic doping strategies is an effective route to boost the average ZT of N-type PbSe. Because Sn and Pb have similar ionic radii and electronegativity, this allows Sn to fill the intrinsic Pb vacancies and effectively improves the carrier mobility of PbSe to 1300 cm2 V-1 s-1. Furthermore, a trace amount of Cu is introduced into the Sn-filled PbSe to optimize the carrier concentration. The extra Cu is situated in the interstitial sides of the lattice, which undergoes a dissolution-precipitation process with temperature, leading to a strongly temperature-dependent carrier density in the material. This dynamic doping effectively improves the electrical transport properties and is also valid to suppress the lattice thermal conductivity. Ultimately, the resulting PbSn0.004Se+3‰Cu obtains a maximum ZT of ≈1.7 at 800 K and an average ZT of ≈1.0, with a 7.7% power generation efficiency in a single-arm device, showing significant potential for commercial application.

Mongrel synthesis of tin (IV) based 3-aminopyridine with hydrogen halides: Structural, optical, thermal analysis, DFT, Hirshfeld surface analysis and antibacterial investigations

The novel organic-inorganic hybrid materials (C5H7N4)2 [SnCl6] 2- (1) and (C5H7N4)2 [SnBr6]2-(2) have been synthesized and characterized by single-crystal X-ray diffraction at room temperature. Both compounds demonstrate the crystal system was triclinic with Pī space group. Hirshfeld surface analysis investigate the intermolecular interactions and crystal packing derived by single-crystal XRD data reveals the closer contacts associated with strong interactions. Infrared spectrum of both compounds shows the NH stretching band at 3396 cm−1 which indicates a protonated amine group. The product crystals optical characteristics were inspected using UV–visible and photoluminescence spectroscopy. The thermal characteristics were evaluated simultaneously using thermogravimetric (TG) and differential thermal analysis. Tin formal oxidation state was determined as +4 through bond valence sum calculations and CSM shows the ideal octahedral geometry of the anions. DFT calculations utilizing the B3LYP method with the LanL2DZ basis set provide optimized geometries and molecular electrostatic potential maps. We explored the energy difference between (HOMO) and (LUMO) orbitals to understand molecular electrical transport capabilities. The biological activity of the investigated compounds are examined against pathogens which indicates efficacy against bacterial strains.

Application of artificial intelligence technologies at substantiation of effective control algorithms for the electrical engineering complex of urban electric transport traction electrical equipment

Background. Studies on the current state and development trends of urban ground public electric transportation in Russia highlight the urgent need for innovative technologies. These innovations should focus on designing and operating new types of rolling stock, traction electrical equipment, and promising types of electric traction. At the same time, special attention should be paid to building autonomous control systems for electric transportation using artificial intelligence technologies. Aim. This study aims to explore the application of neural networks to develop algorithms for effectively controlling the electrical engineering complex of traction electrical equipment in urban ground rail electric transport. Materials and Methods. The research utilized data from studies on the traction electrical equipment modes of rolling stock. These studies were conducted through both computer simulations and field experiments under real operating conditions of urban electric transport using different control algorithms. By applying probability theory and mathematical statistics, the analysis identified the correlations between operational and energy parameters of rolling stock movement and the operational mode of its traction electrical equipment. Results. The identified correlation dependencies informed the design of an effective network architecture, including its size and complexity, as well as the composition of their training samples. This led to the development of an original, simplified algorithm for determining effective control parameters for the electrical complex of traction electrical equipment during the movement of a vehicle on a given section of track. Conclusion. The research concluded that using “simple” neural networks for calculating the parameters of effective control of traction electrical equipment operation modes in urban electric transport provides higher speed and sufficient accuracy compared to complex neural network models. These results are valuable for developers of intelligent control systems for streetcar transportation.

Systems of autonomous running of urban electric transport

The autonomous running system (ARS) is crucial for urban electric transport, ensuring the movement of electric rolling stock even when access to the contact network is lost owing to emergencies or repair work. Thanks to the ARS, the vehicles can maintain their set speeds, providing passengers with comfortable and safe movements. The autonomous running allows vehicles to remain mobile and accessible to passengers, even without power supply from the contact network. ARS increases the reliability and efficiency of urban electric transport, ensuring a more stable operation of the transportation system in the city. This article aims to review the transport systems of urban electric transport and assess their development potential by integrating an ARS into the rolling stock.

MODELIZACIÓN COMPUTACIONAL DE REDES MEMRISTORES: INFLUENCIA DELA CONECTIVIDAD Y LAS CONDICIONES AMBIENTALES EN SU RESPUESTAELÉCTRICACO

With the perspective of implementing neuromorphic devices using memristor networks, we present a numerical-computational platform that allows studying their electrical transport properties. It consists of a function that describes the behavior of an individual memristor (which enables the consideration of an experimental case of interest) and a connection diagram between memristors. Using this platform, two-dimensional networks of various sizes are studied,also incorporating environmental effects (such as humidity and temperature). Furthermore, by selecting the electrically accessible ports, the impact of connectivity on the electrical properties of the network is evaluated. The results indicate that, beyond the individual characteristics of the memristors (determined by the particular selected model), the degree of connectivity, the topology of the connections, and the environmental conditions significantly influence the macroscopic electrical response of the networks.

Controlled Vapor-Liquid-Solid Growth of Long and Remarkably Thin Pb1-xSnxTe Nanowires with Strain-Tunable Ferroelectric Phase Transition.

The Pb1-xSnxTe family of compounds possess a wide range of intriguing and useful physical properties, including topologically protected surface states, robust ferroelectricity, remarkable thermoelectric properties, and potential topological superconductivity. Compared to bulk crystals, one-dimensional (1D) nanowires (NWs) offer a unique platform to enhance the functional properties and enable new capabilities, e.g., to realize 1D Majorana zero modes for quantum computations. However, it has been challenging to achieve controlled synthesis of ultrathin Pb1-xSnxTe (0 ≤ x ≤ 1) nanowires in the truly 1D region. In this work, we report on a Au-catalyzed vapor-liquid-solid (VLS) growth of remarkably thin (20-30 nm) and sufficiently long (several to tens of micrometers) Pb1-xSnxTe nanowires of high single-crystalline quality in a controlled fashion. This controlled growth was achieved by enhancing the incorporation of Te into the Au catalyst particle to facilitate the precipitation of the Sn/Pb species and suppress the enlargement of the particle, which we identified as a major challenge for the growth of ultrathin nanowires. Our growth strategy can be easily extended to other compound and alloy nanowires, where the constituent elements have different incorporation rates into the catalyst particle. Furthermore, the growth of thin Pb1-xSnxTe nanowires enabled strain-dependent electrical transport measurements, which shows an enhancement of electrical resistance and ferroelectric transition temperature induced by uniaxial tensile strain along the nanowire axial direction, consistent with density functional theory calculations of the structural phase stability.

Effect of thermal annealing on the average and local structure of superconducting polycrystalline NbRe films

Abstract NbxRe1−x is a non-centrosymmetric superconductor recently realized in thin film form. The access to the basic physics that governs this material is hindered by the polycrystalline structure of the films which consist of grains of small dimensions. In these conditions, films are not decisive in revealing the nature of the superconducting order parameter, and, in particular, the possible presence of a spin-triplet component. In this work, post-deposition annealing procedures were performed to improve the crystalline quality of the as-grown films. As determined by X-ray diffraction measurements, by tuning the annealing process, it was possible to increase the crystalline size from 1-2 nm up to several nanometers, beyond the values of the superconducting coherence length. Pair distribution function analyses revealed the non-centrosymmetric crystal structure of the treated NbRe films. Finally, electrical transport measurements, performed to study the relationship between structural and transport properties of the samples, showed an improved metallicity and a reduction of the superconducting critical temperature after the thermal treatment. This last result can be reasonably ascribed, for instance, to oxygen contamination, modification of the electronic density of states at the Fermi level, or change in the electron-phonon coupling. The results of this work are useful to realize films for future experiments meant to access nature of the superconducting order parameter.

Controlled single step synthesis, structural and electrode response of honeycomb layered Li3Co2SbO6

We report, for the first time, a single step synthesis process of Li3Co2SbO6 in air medium using the solid state reaction route. The structural analysis confirmed single phase layered crystal structure comprising 2D diffusion path along a-axis and b-axis. The Rietveld refinement of Li3Co2SbO6 yielded monoclinic crystal structure with C2/m space group having cell parameters, a = 5.216 A°, b = 8.989 A° and c = 5.171 A° with Li/Co mixed occupancy. The TEM analysis corroborated the layered structure which is consistent with x-ray analysis. Raman and FTIR analysis confirmed the presence of -CoO6 and -SbO6 octahedra in Li3Co2SbO6 with edge shared arrangement to form a layered stack comprising tunnel type pathway for Li+ ion transport. The estimated electrical conductivity of Li3Co2SbO6 is found to be ∼6.9 × 10−8 Scm−1 with a band gap ∼ 3.5 eV that suggests poor electronic transport for storage cells. This was observed in the electrochemical response of the Li || LiPF6(EC/EMC) || Li3Co2SbO6 cell. The 1st discharge capacity of Li3Co2SbO6 has been found to be a meagre 45 mAhg−1. Despite lower reversible capacity due to poor electrical transport, stable coulombic efficency observed up to 100 cycles suggest the feasibility of improvements in the electrical and charge transport properties.