Conductive Research Articles

Direct Electromagnetic Wave Scattering Calculation Using Methods of Moments through Layered Rough Surface

This thesis focuses on the direct calculation of electromagnetic wave scattering through layered rough surfaces using the Method of Moments. The study aims to contribute to existing knowledge by addressing the problems associated with accurately predicting scattered electromagnetic fields from rough surfaces with layered structures. By using the Method of Moments, this research seeks to provide insights into the behavior of electromagnetic waves when interacting with multi-layered rough surfaces, offering valuable implications for practical engineering applications and the development of advanced computational tools for electromagnetic wave analysis. In practical terms, the surface is typically divided into small patches, and the electromagnetic field at each patch is determined using MoM. This involves solving integral equations describing the interaction between the induced currents on the surface and the incident field. The layered structure may require additional equations to model the reflection of waves and the transmission at the boundaries between the layers. The direct problem is also examined in a two-dimensional picture, where the rough surface profile and the medium are known parameters, and the electromagnetic waves scattered from the surface to the entire space are the unknowns. The rough surface is considered to have a finite length and can be deterministic or arise from a stationary stochastic random process, with a focus on Gaussian-type rough surfaces. The roughness is considered as two basic types: as a perfect electric conductor (PEC) in free space and as a boundary between two dielectric media. The equations of integration obtained are based on the scalar solution of Green's theory, Helmholtz equations, and using Hankel type green functions as kernels due to the one-dimensional nature. The MoM is extensively used to solve these integral equations and is compared to asymptotic approaches and analytical. Various simulations are conducted to test the feasibility of the algorithms, and the results are thoroughly discussed. The study of electromagnetic wave scattering in one-dimensional rough surfaces involves the direct problem, where the field distribution in the whole space is determined using the equation of integration. These equations take into account the surface roughness and medium parameters they are solved using the Method of Moments (MoM) by expressing the field distribution on the surface using basis functions. The direct calculation of electromagnetic wave scattering through a layered rough surface using the Method of Moments (MoM) is a computationally intensive process and complex and. It contains simulating the interaction of EM waves with a complex surface, which presents challenges due to the multiple layers with different properties, and a roughly surface causing and diffraction of incident waves and scattering. When working with a layered rough surface increases the electromagnetic wave interaction complexity. Additional multiple layers introduce considerations, such as layer interfaces and accounting for different material abilities. This requires careful modeling and analysis to exactly capture the behavior of electromagnetic waves as they traverse through and interact with layers. MoM, a commonly used numerical method for solving electromagnetic scattering problems, discreteness the surface into small segments and solves integral equations to determine the fields that is scattered. This approach allows for a maximum analysis of electromagnetic interactions at a grained level.

A simple yet efficient solution for TE scattering from a right trapezoidal groove

AbstractA simple yet efficient solution to the problem of transverse electric (TE) scattering by a two‐dimensional right trapezoidal groove placed in a perfect electric conductor (PEC) surface is presented. Using superposition of plane waves and applying the Neumann boundary condition at the groove walls, the transverse magnetic field is expressed as the sums of infinite series of waveguide modes. Considering the equivalent magnetic current on the aperture, a Fredlholm's integral equation with logarithmic singular kernel is extracted and then discretised by a collocation method based on a piecewise constant approximant. The extracted linear system of equations can be easily solved by the matrix methods for the unknown coefficients. Numerous examples are presented to verify the results and show the ability of the proposed method. Finally, this method is employed to examine the effect of the groove parameters and incidence angle on the scattering signatures.

Переменный электрический ток в угольных шахтах: электромагнитная энергия и превращение её в электрический ток

The article addresses the challenge of improving the competence and basic knowledge of specialists working with alternating electric current. The purpose of this work is to explain the magnetic properties of substance, generation of magnetic field and electric current with due account for the known laws of physics and the Quantum theory. We believe that addressing these tasks needs to begin with the energy produced by the magnet. The method of inducing electric energy using magnetic field of a permanent magnet is chosen as the research subject. The historical mythological bases of interpreting the induction of electric energy are shown. Modern instruments prove that the magnetic field is the electromagnetic emissions of magnets. A hypothesis regarding the origin of magnetic properties of substance is developed based on analysis of the known magnetic properties of alpha-iron. Two features of the magnetic properties of substance have been revealed, which differ from Ampere's ideas. The first is the local volume of atoms combined by short-acting covalent bonds, forming a natural crystalline or artificially elongated structure. The second is that the frequency of electromagnetic emissions by the valence electrons of all the atoms in Hertz is approximately the same. The total radiation of energy by all the atoms in local formations generates a magnetic field. The hypothesis is confirmed by circuits and information on instruments that measure the emission of magnets in Hertz. When the energy absorbed by electrons increases, the bond between atoms is broken and magnetic emissions cease. All substances in liquid and solid aggregate state begin to radiate electromagnetic emissions to other substances under the impact of external electromagnetic emissions. This is confirmed by photographic evidence of the performed experiments. A hypothesis is proposed, which differs from the ideas about the movement of free electrons by the fact that the formation of electric current is the result of absorbing electromagnetic emissions of the magnet by valence electrons of the electrical conductor and their transfer into the electric network. The physical phenomena of energy transfer between the transformer windings in an electric circuit prove that electric current is a concentrated flow of electromagnetic emissions, which are a wave form of energy.

Electrodeposited Nanowires for High Density Interconnects of GaN-Based MicroLEDs

For next-generation applications, fully controllable gallium nitride (GaN)-based micro light emitting diode (microLED) arrays will play a crucial role. These feature high pixel densities, high intensities, and high efficiencies. Well-established top-down etching processing schemes of pristine LED wafers allow for an easily accessible and scalable fabrication approach for microLED arrays down to the single digit µm dimensions with dies featuring several 100,000 on a square centimeter. At this scale, classical bonding approaches like wire bonding fail to harvest the true potential of such an array due to inherit technological restrictions. To allow for the individual controllability of every pixel a highly scalable integration approach to a CMOS backplane is necessary. Established processes for the realization of such an integration often feature major drawbacks. Indium bumps deposited via thermal evaporation generally fulfill the scale requirements but fail to adapt to the unique challenges of such hybrid integration. High non-planarity of the substrate, high wafer bow, and mismatching thermal expansion coefficients can lead to diminishing bonding yields and hence functioning microLEDs during the high-temperature bonding step necessary for indium bumps. Additionally, Indium is an inferior electrical and thermal conductor to other metals and limits the active performance of the device while also restricting its usage area due to its low melting point. In the currently ongoing EU Project SMILE, we are developing GaN-based microLED arrays up to 512 x 512 pixels and thoroughly examine established bonding technologies as well as an in-house developed metal nanowire approach. The necessary perquisites for electrochemical deposition, namely the conductive seed and the removal thereof can easily be integrated into the device’s processing scheme. Nanowires are electrochemically deposited out of a liquid solution at room temperature onto the microLED array and the CMOS backplane. The direction, length, and diameter of the nanowires can easily be controlled to accustom different proportions and bonding geometries. Inline monitoring via the recorded amperogram allows for the differentiation of the individual stages of nanowire growth during the electrochemical deposition. Mechanically stable and electrically sufficient interconnects can then be realized by pressing the nanowires of both substrates into each other. The high aspect ratio of the wires results in a high surface area and allows for nanowires of both substrates to intertwine forming stable connections with large contact surfaces at low pressures without any additional heating steps necessary. Due to the variability of the wire length and ongoing intertwining during the bonding, non-planarities and wafer bow can be accommodated. This flexible bonding behavior is a unique advantage of bonds based on metal nanowires. The junctions approach the conductivity of bulk material and are crucial for the thermal management of the microLED array. The final LED device generates a substantial amount of heat, which cannot be cooled meaningfully via convection to the surrounding air or by its radiation. Consequently, a capable thermal conduction towards the silicon chip is necessary for heat management. Here the metal nanowires play a crucial role in providing this thermal connection via the bonding interface, which potentially allows for improved device performance over other bonding technologies.

Ni-P Electroless Plating of Polyethylene Terephthalate Fibers with Various Twist Number Utilizing Supercritical CO2-Assisted Catalyzation

Weavable devices are multifunctional fabric-based devices prepared by weaving various functional fibers into a single piece of fabric. Metalized polymer fibers are promising electrical conductors for such weavable devices because of the decnet electrical conductivity derived from the metal coating and flexibility arising from the polymer fiber. However, ensuring both sufficient electrical conductivity and stability in these metalized polymer fibers for practical device application remains challenging because of the insufficent adhesion between the metal coating and polymer fiber. An electroless plating with the catalyzation step performed in supercritical carbon dioxide (sc-CO2)1 is developed to produce metallized polymers possessing high electrical conductivity and good adhesive properties between the metal coating and polymer fiber. In application, fibers are often twisted to enhance a specific property, such as the mechanical property, and the twist number (twist per meter, T/m) is expected to affect the electroless plating performance.In this presentation, Ni-P electroless plating of polyethylene terephthalate (PET) fibers with a different twist number (twist per meter, T/m) is reported. The sc-CO2-assisted catalyzation was utilized to achieve electroless plating of Ni-P coatings on the PET fibers. The electrical resistance of the Ni-P/PET fibers was decreased following an increase in the twist number as listed in Table 1. Elemental analyses revealed that the Ni content in the Ni-P coating was higher for the PET fibers with a larger twist number. This tendency corresponded well the the electrical resistance results since Ni-P with a higher Ni content is expected to have a lower electrical resistance. Results obtained in this study indicate that PET fibers with a larger twist number is beneficial for the electroless Ni-P plating by decreasing of the electrical resistance in the fabricated Ni-P/PET fibers. Reference T.-F.M. Chang et al., Microelectron. Eng. 2020, 223, 111233. Figure 1

Two-Phase Flow Through the PTL of PEM Water Electrolyzer: MRI Experiments and Numerical Modeling Using Phase-Field Theory

In 2021, estimation shows that the worldwide annual hydrogen production is around 94 Mt. Exploitation of native hydrogen being not mature, it is obtained by its separation from other elements by different methods such as steam methane reforming, and electrolysis of water. The latter supplied by a renewable power source will take part in the development of a green hydrogen economy [1]. In this context, Proton Exchange Membrane (PEM) Electrolyzer is a promising technology due to its flexibility and very quick adaptation to load variations. However, its current development still confronts some limitations at a large industrial scale. For instance, efficiency and durability are directly impacted by the mass transport and electrical transfer within the porous materials at the anode side. Limitation of the water supply to the catalyst layer happens once there is a poor oxygen evacuation which decreases the performance of the device by inducing high overpotential. Furthermore, the PTL has an important role as an electrical conductor for charge transfer from the catalyst layer [1]. The efficiency of all the transport phenomena through the PTL and porous electrode assembly depends on their transport properties which are related to their microstructure and operating conditions. For instance, PTL with a large pore size allows good water and gas transport, while produced electrons choose a long-distance path generating an electrical resistance higher than that in the case of PTL with a small pore size [1]. So, controlled and optimum porosity and pore size could contribute to efficient water, gas, and electron transport. To define the best porous layers morphologies, a deep and accurate understanding of the phenomena is developed in this work by combining modeling and experiments.The magnetic resonance imaging (MRI) technique was used to quantify the water content within the porous layer during the two-phase flow. Instead of the real PTL made of titanium which is paramagnetic and cannot be used in the MRI, borosilicate filters with thickness, porosity, and pore size similar to the PTL were used. After positioning the sample in the 600 MHz vertical imager (Figure 1-A), a constant water flow rate is introduced while the gas flow rate is varied. The saturation profiles measured through the porous material depend on the gas flow rate and a semi-dryness of the sample occurs (Figure 1-B) with a residual quantity trapped between pores (minimum stable water content). The water flow rate variation in the channel does not affect saturation, but a higher gas flow rate is needed to reach a minimum stable water content for higher water flow rate.The gas pressure drop through the porous medium was measured and bubble formation in the channel was also analyzed. The results show that the pressure drops and types of flow (slug, annular, and bubble flow) depend on orientation of the water channel (horizontally and vertically) and flow direction (up or downward), and on the water and gas flow rates.To reach a better understanding of the dynamic characteristics of water and oxygen transport over the PTL, the phase-field model based on the Cahn-Hilliard theory was used to simulate the two-phase flow through a porous medium [2]. In this model, the modified Navier-Stokes equations for two phases are coupled with a phase-field equation for describing the diffuse interface. Numerical simulations performed in the COMSOL® multiphysics software were carried on 2D geometries composed of spherical solid grains of different sizes, having properties similar to the PTL used in the MRI experiments. Gas is injected on one side of the sample and flows through the porous medium initially saturated and evacuated on another side in contact with the water channel (Figure 1-C). Gas flow in the porous medium and bubble formation in the water channel are studied while varying the gas and water flow rates. The simulation results give information about the gas pathways within the porous medium and the saturation profiles over time, depending on the gas/water flow rates, which will be compared with experimental results.[1] J. Parra-Restrepo, “Caractérisation des hétérogénéités de fonctionnement et de dégradation au sein d’un électrolyseur à membrane échangeuse de protons (PEM),” Université de Lorraine, 2020.[2] J. W. Cahn and J. E. Hilliard, “Free Energy of a Nonuniform System. I. Interfacial Free Energy,” The Journal of Chemical Physics, vol. 28, no. 2, pp. 258–267, Feb. 1958. Figure 1

(Invited) Confined Electrodeposition Enables Additive Manufacturing of Metals at Micro- and Nanoscale

Additive manufacturing, also commonly known as 3D printing, is rapidly becoming a part of our everyday life: from DIY use by hobbyists to industrial manufacturing, 3D printing is experiencing a booming success. The technologies advance quickly with faster print rates, broader choice of materials and a constantly increasing accuracy and printing resolution. Impressively, state-of-the-art techniques take the printed feature sizes to the extreme: multiphoton optical stereolithography and focused electron or ion beams are now capable to produce objects with nanoscale resolution. Although at the cutting edge to printing finest details, these advanced manufacturing methods lack the capacity to process dense and pure electrical conductors – materials very much needed to push the limits of the technologies of the future – sensors, energy storage devices, logical gates and memory interfaces.Electrochemical methods, which have an advantage to process a wider range of materials – conductors and semiconductors, bulk materials and colloids, at a first glance, have little to do with additive manufacturing. Electrodeposition, a well-established approach traditionally used to produce metallic coatings or thin films, is often integrated in microfabrication process but is limited to planar two-dimensional designs. However, when combined with state-of-the-art nanoelectrochemical approaches, electrodeposition can be taken into a three-dimensional realm, where it can be used to produce complex structures with micro- and nanoscale dimensions [1]. The key to achieve this is nanoscale confinement of precursor delivery that is combined with layer-by-layer additive processing. Liquid manipulation by pressure driven flow through nanoscale cantilevers [2] or intermittent meniscus formation using droplet cells [3] – a variety of nanoelectrochemical techniques can be used to fabricate metallic structures with various morphologies. The recent advances in these technologies including instrumental aspects, performance metrics such as resolution and print rates, as well as some materials characteristics are highlighted in this talk.

Effect of Borophene on the Electrochemical Performances of Li7P3S11 based AllSolid-State Lithium Sulfur Batteries

This study has investigated the effect of 2-dimensional (2D) beta borophene as a cathode additive for all-solid-state lithium-sulfur batteries. The comparisons have been carried out regarding the impact on ionic conductivity based on borophene content. Although the studies of borophene's contributions in the literature on the anode component, this study focuses on the cathode contribution for the first time. While MoS2 has been selected as the cathode active material, carbon black has been selected as the electrical conductor, and Li7P3S11 solid electrolyte has been synthesized as an ionic conductor in all-solid-state lithium-sulfur cells. Borophene has been synthesized from boron powder by the exfoliation method. As a cathodeactive material, MoS2, containing sulfur, and its 2D material nature, eliminates many of the disadvantages that sulfur exhibits when used alone. To investigate the effect of borophene on ionic conductivity in all-solid-state lithium-sulfur cells, multicomponent composite cathodes were prepared in (MoS2 / Conductive Carbon / Li7P3S11 + Borophene) overall compositions. According to the results, the specific capacity of the cells is affected negatively, while the stability of the cell is affected positively when increased the borophene amount.

Review of: "Graphene in nMOS field-effect transistors is an excellent electrical conductor, and also has outstanding spintronic properties."

Review of: "Graphene in nMOS field-effect transistors is an excellent electrical conductor, and also has outstanding spintronic properties."

Strength-conductivity synergy via lean alloy design: A study on novel solid stir extrusion of an Al-2Cu-0.1 Nb-0.15Zr (∼wt.%) alloy

Aluminum alloys find wide applications in power and transmission cables, and electrical conductors due to their advantageous properties of high electrical conductivity, and lower cost per unit. However, the lower tensile strength compared to copper poses a challenge for the mechanical stability of aluminum-based cables. In this study, we addressed this issue by adopting a process-based alloy design approach, creating a lean alloy with a dilute composition of Al-2Cu-0.1 Nb-0.15Zr (∼wt.%). The alloy was processed using a friction stir based novel SolidStir® (SSE) technique, followed by low-temperature aging. The resulting aluminum wire exhibited improved strength (240 MPa) while simultaneously enhancing electrical conductivity (64%IACS). The study employed computational simulations (Thermocalc) and experimental techniques (differential scanning calorimetry and transmission electron microscopy) to thoroughly investigate the microstructure. Microstructural examinations revealed that the precipitation kinetics in SSE and SSE+aged conditions played a significant role in enhancing strength and electrical conductivity. These findings demonstrate the successful achievement of high strength and high electrical conductivity in aluminum wire through a lean alloy design approach.

Alkali Metal Cation-Sulfate Anion Ion Pairs Promoted the Cleavage of C-C Bond During Ethanol Electrooxidation.

Direct ethanol fuel cells show great promise as a means of converting biomass ethanol derived from biomass into electricity. However, the efficiency of complete conversion is hindered by the low selectivity in breaking the C-C bond. This selectivity is determined by factors such as the material structure and reaction conditions, including the nature of the supporting electrolyte. Cations serve not only as facilitators of electricity conduction through ion migration but also as influencers of the reaction pathways. In this study, we utilized differential electrochemical mass spectrometry to track the in situ generation of CO2 during potential scanning. The presence of alkali cations led to an enhancement in the CO2 selectivity. In addition, in situ Raman spectroscopy provided evidence of the formation of alkali metal cation-sulfate anion ion pairs. The catalytic activity and CO2 selectivity were found to be directly correlated to the ionic strength of these ion pairs.

A Symmetric FDTD Subgridding Method With Guaranteed Stability and Arbitrary Grid Ratio

A finite-difference time-domain (FDTD) subgridding method is proposed to efficiently and accurately solve three-dimensional electromagnetic problems. Based on the reciprocal and symmetric interpolation operators between coarse and subgridding meshes, spatial coupling matrices are carefully designed to guarantee long-time stability. To further enhance its capability of handling multiscale structures, arbitrary grid ratios and nested subgridding meshes are extended to be supported in the proposed method. In addition, the rigorous analysis shows that the proposed FDTD subgridding method is theoretically stable. Five numerical examples including a simple cavity with perfect electric conductors, a rectangular TEM waveguide, a dielectric resonator, a single-layer substrate integrated waveguide, and a large airplane platform with a dipole are carried out to validate its effectiveness. Results show that it is stable, accurate, efficient, and easy to model complex structures.

Evaluation of the effectiveness of an electromagnetic shielding enclosure at low frequencies

We construct an electromagnetic shielding enclosure with dimensions of 95 cm × 95 cm × 95 cm. It is made from aluminum and copper which are high electrical conductors and nonmagnetic materials, so the enclosure does not produce additional static magnetic field. The enclosure is composed of a cubic frame (25-mm aluminium rails) and 6 removable panels. Each panel consists of a copper mesh (wire diameter of 0.25 mm and 0.58 mm spacing) sandwiched in a double layered aluminium frame, two aluminium handles, and 4 aluminium hooks. The electromagnetic shielding effectiveness of the enclosure is evaluated using the standard method at low frequencies, 0.4–25 MHz. A function generator and a circular flat coil with a diameter of 5 cm are used to transmit sinusoidal electromagnetic waves directed to the enclosure. The electromagnetic waves transmitted into the enclosure are measured by a spectrum analyser and another similar circular flat coil. The measurements show that when the frequency is increased from 0.4–2.5 MHz, the shielding effectiveness slightly increases from 42.2–48.6 dB. For the frequency between 3–25 MHz, the shielding effectiveness remains at around 49.6 dB with a standard deviation of 0.6 dB. Such shielding enclosure is potentially improving the accuracy of many investigating techniques which use electromagnetic waves with low frequencies including nuclear quadrupole resonance and magnetic induction tomography.

Interplay between chiral media and perfect electromagnetic conductor plates: Repulsive vs. attractive Casimir force transitions

We determine the Casimir energies and forces in a variety of potentially experimentally viable setups, consisting of parallel plates made of perfect electromagnetic conductors (PEMCs), which generalize perfect electric conductors (PECs) and perfect magnetic conductors (PMCs), and Weyl semimetals (WSMs). Where comparison is possible, our results agree with the Casimir forces calculated elsewhere in the literature, albeit with different methods. We find a multitude of known but also new cases where repulsive Casimir forces are in principle possible, but restricting the setup to PECs combined with the aforementioned WSM geometry, results in purely attractive Casimir forces.

Review of: "Graphene in nMOS field-effect transistors is an excellent electrical conductor, and also has outstanding spintronic properties"

Review of: "Graphene in nMOS field-effect transistors is an excellent electrical conductor, and also has outstanding spintronic properties"

Enhancing electromagnetic properties through carbon Nanotube-Based polymer composites

In this study, electromagnetic [EM] wave-absorbing property material was fabricated from a polymer composite material with [0°/90°]s fiber orientation and Multiwall Carbon Nanotubes (MWCNTs) as filler materials, and with a Perfect Electric Conducting (PEC) material. The experiments are conducted for the composites with PEC-coated and non-PEC-coated materials, using a Vector Network Analyzer by X-band in the frequency range of 8.2 to 12.4 GHz. The characteristics like EM properties and microwave (MW) absorbing properties were calculated in terms of permeability, permittivity, and reflection losses. In addition, mechanical, thermal, and morphological analysis was also performed. The EM absorbing properties were found to be strong for the composites at 5 % reinforcement and for PEC-coated specimens, i.e., −38.69 dB at 10.5 GHz. A similar trend was followed for both mechanical and thermal properties. The CRITIC analysis was performed for these experimental data of EM, mechanical, and thermal properties. By this analysis, the weight percentages were calculated, which defines the sequence order in which the fabricated composites are capable of sustaining all properties. The highest weight percentage obtained for the weight loss parameter (thermal property) was 16.3 %, and the lowest percentage obtained for thermal degradation was 9.7 %.

Environmental conical nozzle levitator equipped with dual wavelength lasers

AbstractThe environmental conical nozzle levitator (E‐CNL) with dual‐wavelength lasers is an extreme environment materials characterization system that was designed to investigate ultra‐high‐temperature materials: refractory metals, oxides, carbides, and borides above 3000 K in a controlled atmosphere. This article details the characterizations using this system to establish its high‐temperature capabilities and to outline ongoing work on materials under extreme conditions. The system has been used to measure the melting point of several oxide materials (TiO2, Tm = 2091 ± 3 K; Al2O3, Tm = 2310 3 K; ZrO2, Tm = 2984 31 K; and HfO2, Tm = 3199 ± 45 K) and several air‐sensitive refractory metals (Ni, Tm = 1740 K; Ti, Tm = 1983 K; Nb, Tm = 2701 K; and Ta, Tm = 3368 K—note: mean ± standard deviation) during levitation which matched literature values within 0.17–2.43 % demonstrating high accuracy and precision. This containerless measurement approach is critical for probing properties without container‐derived contamination, and dual‐wavelength laser heating is essential to heat both relatively poor electrical conductors (some refractory metals and carbides) and insulators (oxides). The highest temperature achieved utilizing both lasers in these experiments was ∼4250 ± 34 K on a 76.6 mg, molten HfO2 sample using a normal spectral emissivity of 0.91. Stable levitation was demonstrated on spherical samples (yttria‐stabilized zirconia) while adjusting levitation gas composition from pure oxygen to pure argon, verifying atmospheric control up to 3173 K on solid or molten samples. These successes demonstrate the viability of in situ high‐temperature environmentally controlled studies potentially up to 4000 K on all classes of ultra‐high‐temperature materials in one system. These measurements highlight the E‐CNL system will be essential for the development of next‐generation ultra‐high‐temperature materials for hypersonic platforms, nuclear fission and fusion, and space exploration.

On Entropy Measures of Some Titania and Carbon Nanotubes

A nanotube is a nanometer–scale tube-like structure, it is a kind of nanoparticle, and may be large enough to serve as a pipe through which other nanoparticles can be channeled, or, depending on the material, may be used as an electrical conductor or an electrical insulator. For computing the structural information of nanotubes, the graph entropies have become the information theoretic quantities. The graph entropy measure has attracted the research community due to its potential application in discrete mathematics, biology, and chemistry. In this paper, our contribution is to explore graph entropies for structures of some nanotubes based on novel information function, which is the number of different degree vertices along with the number of edges between various degree vertices. More precisely, we computed entropies of some classes of nanotubes such as titania nanotube TNT[Formula: see text], TNT[Formula: see text] and carbon nanotubes HAC[Formula: see text] by making a relation of degree-based topological indices with the help of information function.

Heterogeneous metallic glass composites with a unique combination of strength, plasticity and conductivity

Metallic glass-reinforced Cu-based composites offer a promising avenue for overcoming the trade-off between high strength and high electrical conductivity in materials. In this investigation, heterogeneous CuZrAl metallic glass-reinforced CuCrZr alloy composites are prepared through spark plasma sintering and a one-step hot pressing. The microstructural evolution of the composites during the preparation process and its correlation with mechanical and electrical properties are revealed. Grain refinement and dislocation accumulation in the CuCrZr alloy matrix resulted in strength gain and a trade-off in electrical conductivity. However, precipitation of the Cr-rich phase compensates for the loss of conductivity. Directional strengthening and toughening of the composites are achieved by inducing deformation of the CuZrAl metallic glass reinforcement in the undercooled liquid region to attain its ordered arrangement. Furthermore, the electrical and mechanical properties of the crystalline phase Cu10Zr7 at the edge of metallic glass are predicted and investigated using first-principles calculations, with a focus on its impact on the performance of composites. A novel Cu-based metallic glass composites fabricated using an efficient processing approach offers valuable insights into material selection for electrical conductor applications.

Review of: "Graphene in nMOS field-effect transistors is an excellent electrical conductor, and also has outstanding spintronic properties"

Review of: "Graphene in nMOS field-effect transistors is an excellent electrical conductor, and also has outstanding spintronic properties"