Conductive Plate Research Articles

Analysis of electromagnetic scattering from typical targets for orbital‐angular‐momentum waves: Theoretical model

The target scattering characteristics in microwave band are necessary to be researched for Orbital-Angular-Momentum (OAM) wave-based radar applications. A theoretical description of electromagnetic (EM) scattering from a typical target by OAM waves is proposed in this paper. First, OAM waves are decomposed into plane waves in the spectral domain with different elevation and azimuth angles. Then, the scattering form of each decomposed plane wave is determined through coordinate system transformation and physical optics approximation. Formulas and numerical results are presented for OAM-based radar scattering cross section of a perfect electric conductor and dielectric plate and a cylinder. Unlike the conventional results of EM plane wave scattering, the scattering properties of OAM waves from plate and cylinder are analysed with particular emphasis on OAM mode influence. The results provide insights into OAM wave-matter interactions and may find important applications in wave propagation and OAM wave-based radar detection and imaging.

Fabrication of "electroactive cells" using bio-inspired polydopamine-derived carbon nanoparticles for manipulation of cells with electrical stimulation.

In this study, we report some bio-inspired carbon nanoparticles (CNPs) that exhibit high fluorescence quantum yields, good conductivity, excellent dispersion in aqueous solution, high cell-uptake efficiency, and no cytotoxicity as well. We were inspired by mussels’ adhesive components to synthesize polydopamine nanoparticles and then use a carbonization process to prepare fluorescent CNPs. Using some surfactants, we could control the sizes of CNPs and increase their dispersion in water. Fluorescence spectroscopy confirmed the excitation of CNPs at 360 nm and emission of blue light with a 400–450 nm wavelength. High quantum yields of greater than 20% were also measured. Transmission electron microscopy proved that the addition of surfactants could shrink particles to several nanometers in size. The fluorescent and conductive CNPs were applied to stain L929 fibroblast cells in vitro, finding no harmful effects on cells. Due to the polydopamine-derived CNPs’ good electrical, fluorescent, and biocompatible response, we designed a platform to manipulate the cells after endocytosis of conductive CNPs to observe the effects of electrical stimulation on cell attachment, cell growth, and cell death. The nanoparticles endocytosed by cells seemed more easily attracted to the electric field, leading to enhanced cell attachment and growth. Therefore, CNP uptake can increase the attachment of cells onto a conductive plate electrode in a short time (within 10 min at 4°C). When the source of the electric field was changed to rod electrodes in the medium, cells that had been pre-adsorbed onto a non-conductive plate were desorbed from the plate and destroyed. Therefore, addition of CNPs during cell incubation can allow control of cell growth and death via manipulation of electric fields.

Determination and Analysis of Joule’s Heat and Temperature in an Electrically Conductive Plate Element Subject to Short-Term Induction Heating by a Non-Stationary Electromagnetic Field

We propose a mathematical model that allows us to determine the temperature field of a parallel-sided electrically conductive plate element subject to uniform non-stationary electromagnetic action. We formulate initial-boundary value problems to determine the parameters of the non-stationary electromagnetic field (NEMF) and the temperature. We develop a methodology to solve these initial-boundary value problems using the approximation of determining functions by cubic polynomials over thickness of the plate element. General solutions for the related Cauchy problems at uniform non-stationary electromagnetic action are obtained. Based on these solutions, the temporal variation of Joule’s heat and temperature in the plate element, subject to short-term induction heating by an NEMF in the mode of impulse modulating signal (MIMS), is analyzed. Temperature dependencies on the different values of electromagnetic field stress and on the different time duration were obtained. The choice of the carrier frequency of electromagnetic field oscillations is explained for the frequencies mostly used in industrial devices for inductive heating.

Judgment of mode crossing avoidance in characteristic mode analysis

The consistent interpretation of modes is crucial in characteristic mode analysis, which can usually be achieved by mode tracking algorithms. However, the problem of the eigenvalue crossing avoidance is still challenging to solve completely. In this paper, the possible causes of the eigenvalue crossing avoidance are discussed, and divided into two types. According to the characteristics of the modes with the cross avoidance, a comprehensive method for locating the frequency of crossing avoidance is first proposed. Since the crossing avoidance occurs in the case of degenerate mode coupling, the decoupling method is applied to eliminate the mode cross avoidance. Finally, the method’s effectiveness is verified by dealing with crossing avoidance problems of a rectangular conductor, dipole, and skewed plate structure. The proposed method is only related to the mode number to be discussed, and its calculation is time-saving.

A High Conductive Composite Bipolar Plate with Conductive Network Constructed by Chemical Vapor Deposition

In this study, a highly conductive composite bipolar plate with an embedded conductive carbon nanofiber network was prepared by chemical vapor deposition, and a conductive network was constructed inside the composite bipolar plate. The latter network was then compared with a conductive network formed by directly adding carbon nanotubes more evenly distributed. The optimum preparation methods of vapor-grown carbon fibers and the fiber content were analyzed, and the specific surface area and porosity of the bipolar plates were measured and analyzed using a BET test. The results show that the carbon nanofibers prepared under the conditions of 700 °C and a content of 2% exhibited the best effect on improving the performance of the bipolar plates. The conductivity of the prepared bipolar plates could reach 255.2 S/cm, which is 22.1% higher than treatment with multi-walled carbon nanotubes. The bending strength of the prepared bipolar plates was 47.92 MPa, and the interface contact resistance was 6.24 mΩ·cm2. In conclusion, the bipolar plates modified with vapor-grown carbon fibers were a promising kind of material for proton exchange membrane fuel cells.

Topology optimization of DC-biased pot-type reactor using design sensitivity in steady state of electromagnetic field with magnetic nonlinearity

Because reactors applied to electric vehicles are typically driven under a DC-biased current, a constant inductance property is required. When a high-performance DC-biased reactor is designed, the topology optimization (TO) is an effective design method owing to the high degree of structural change in the magnetic circuit. However, there exists no report regarding the TO method in the steady-state time domain with magnetic nonlinearity. In this paper, based on the time-domain adjoint variable method, a novel sensitivity analysis approach for the steady-state time domain with thorough consideration of the magnetic saturation is proposed. Through the proposed method, the TO of the iron core and winding structures in a pot-type reactor was carried out to enhance the DC-biased characteristics. Furthermore, the eddy current loss occurring on the aluminum plate installed outside the reactor was suppressed by the multi-objective TO. The interesting structure of a pot-type reactor that enhanced the DC-biased characteristics and reduced the eddy current loss on the outer conductor plate was also illustrated.

On Wire-Grid Representation for Modeling Symmetrical Antenna Elements

This paper focuses on the combination of the method of moments and the wire-grid approximation as an effective computational technique for modeling symmetrical antennas with low computational cost and accurate results. The criteria and conditions for the use of wire-grid surface approximation from various sources are presented together with new recommendations for modeling symmetrical antenna structures using the wire-grid approximation. These recommendations are used to calculate the characteristics of biconical and horn antennas at different frequencies. The results obtained using different grid and mesh settings are compared to those obtained analytically. Moreover, the results are compared to those obtained using the finite difference time domain numerical method, as well as the measured ones. All results are shown to be in a good agreement. The recommendations used for building a symmetrical wire-grid of those symmetrical antenna elements provided the most advantageous parameters of the grid and mesh settings and the wire radius, which are able to give quite accurate results with low computational cost. Additionally, the known equal area rule was modified for a rectangular grid form. The obtained radiation patterns of a conductive plate using both the original rule and the modified one are compared with the electrodynamic analysis results. It is shown that the use of the modified rule is more accurate when using a rectangle grid form.

Komparasi Output Termoelektrik Generator ( Kuat Arus Dan Tegangan ) Pada Jalas Aspal Dan Beton Dengan 3 Variasi Bentuk Plat Tembaga

Solar radiation heat energy is energy that propagates throughout the earth's surface and is absorbed stored in various objects on the earth's surface. A thermoelectric generator is an electrical generator device that converts heat (temperature difference) directly into electrical energy, using a phenomenon called the Seebeck effect. In this research, this research was carried out by utilizing the absorption of solar radiation heat on a concrete road with a type of cast concrete class III with K 250 and asphalt type AC-WC as a thermoelectric generator. This research uses 3 thermoelectric generator modules type 1848 which will be arranged in series, the cooling system is filled with water using 2 asphalt and concrete variables, each of which has three variations of L, I and Z-shaped heat conductor plates. The test results show that asphalt has energy larger than concrete. L plate is the best plate on both asphalt and concrete roads. This research allows it to be developed to become a reference source of the latest alternative energy.
 Keywords: Heat Energy, Thermoelectric generator, Plate variation

Joint Inversion with Borehole and Semi-Airborne TEM Data Based on Equivalent Filament Approximation

The borehole transient electromagnetic (TEM) method can be useful in deep mineral exploration to detect blind ore bodies beside or below the borehole, and is especially adapted to finding small-scale, deep, rich ore bodies. In this method a transmitting loop is deployed on the top surface of the Earth, while a receiving coil is moved down the borehole. As the borehole TEM method is limited by the borehole’s location and depth, so its exploration scope is limited. The surface to airborne TEM method is a semi-airborne TEM configuration that transmits on the surface and receives TEM response in air. The two systems are combined into one system in this study, sharing the transmission loop deployed on the surface. With this combined system, the TEM response in the borehole and in the air can be observed at the same time. This paper employs a joint interpretation method based on the equivalent filament, which is introduced to obtain more reliable geometric information for the target with both borehole and aerial TEM data. The eddy currents induced in a thin confined conductor can be represented by equivalent current filaments, and the distribution of filaments can reflect the position and geometry of the conductor. Therefore, geometric parameters of targets can be obtained by filament inversion, and the joint inversion can be more accurate with both borehole and aerial response. Numerical modeling results show that the joint inversion based on the equivalent filament results can reliably obtain the geometric parameters of the thin conductive plate embedded in half space.

Mutual inductance model of double printed circuit board‐based coplanar rectangular spiral coils for eddy‐current testing

AbstractIn the field of eddy‐current testing (ECT), most studies on detection probes are primarily based on circular solenoid coils; related research on rectangular spiral coils is rare. In this study, an analytical model of the mutual inductance (MI) between two coplanar rectangular spiral coils was developed in which the two coplanar rectangular spiral coils were placed above a conductive plate. The MI calculation does not need to consider the thickness of the coils, which is consistent with the actual situation of the printed circuit boards (PCB)‐based spiral coils, and simplifies the multi‐turn rectangular spiral coil into a set of concentric single‐turn coils. Two experimental setups were constructed to verify the analytical model and they were used to detect defects in the aluminium plate. The experimental results indicate that the analytical model can be used to evaluate the performance of ECT probes using PCB‐based spiral coils, through the geometrical dimensions of the coils, centre distance and lift‐off, and so forth. Compared with traditional methods, this method can still obtain satisfactory calculation accuracy after ignoring thickness parameters. The analytical model is also an effective tool to aid in the design of detection probes and optimisation of related parameters.

Experimental investigation of high velocity neutral flow interaction with a magnetized plasma

Plasma aerocapture is an orbit insertion method that leverages a magnetic dipole plasma to generate drag by ionizing, capturing, and deflecting atmospheric flow. Key physical assumptions about energy and momentum exchange during aerocapture are tested here by a novel experiment that characterizes the interaction between a high velocity free molecular flow and a magnetized plasma. A neutral beam source accelerates ions from a helicon plasma to a conductive plate, neutralizes them, and reflects them as a collimated flow. A hollow cathode plasma with an applied axial magnetic field of 1 kg acts as the target for the flow. It is found that interaction with the flow causes an increase in both density and temperature of the target plasma by up to a factor of two. The voltage required to operate the hollow cathode at a fixed current is reduced by up to 5% while the neutral beam is operating, suggesting power deposition by the flow. A 0D power balance model is invoked to show that flow kinetic energy is absorbed by the plasma at a rate of up to 50% of the hollow cathode power. The absorbed power correlates linearly with an electron temperature increase of up to 100%, indicative of electron heating by flow kinetic energy transfer. Deflection of the flow by the plasma is not resolved due to extraneous forces on the measurement device and uncertainties in plasma properties. Using the results found here, it is shown that the experiment can feasibly scale to demonstrate significantly higher energy and momentum transfer as required for a plasma aerocapture proof-of-concept.

An analytical model of an eddy‐current coil near the edge of a conductive plate

Truncated region eigenfunction expansion (TREE) method is applied to the analysis of impedance change of a coil in the vicinity of the edge of a metal plate. The analysis is carried out with the second order vector potentials (SOVPs) and provided for both cylindrical and rectangular coils. By full discretisation of the eigenvalues, double series solutions are obtained for the field and coil impedance variations. To simplify the solving procedure further, a novel approach for the determination of eigenvalues is proposed by means of the 1D finite element method (FEM), which is easy to implement and works well for the plate of non-magnetic material. Numerical results for the impedance variations of cylindrical and rectangular coils are compared with those of 3D FEM simulation, by which the efficiency and accuracy of the authors’ method are confirmed, and the former is much faster and more memory efficient.

Eddy Current Microsensor Dedicated to the Nondestructive Testing of Conductive Plates

To ensure the safety of transportation and prevent accidents, nondestructive testing by Eddy current (EC) is proposed to check the conditions of industrial parts. EC sensors are used for the inspection of defects in conductive parts using coil fed by alternative current. These sensors are sensitive to defects, easy to implement, and robust for industrial applications. In order to satisfy the requirement for both reliability and speed during inspection operations, innovative EC sensors that can provide higher sensitivity, better spatial resolution, and more information about the defect characteristics, such as microsensors, are developed. The miniaturization of these sensors’ coils conforms the sensor for micro-defects in critical parts and in complex materials. In this paper, a microsensor dedicated to EC application is studied and characterized to identify the coil parameters and to optimize the geometry of the probe. An approach for the modeling of microsensor dedicated to EC nondestructive applications is proposed. The moving band finite element method is implemented for this purpose to take into account the movement of the sensor and to simplify the modeling of EC testing configurations that use this kind ofsensor. Experimental validations were conducted on a nickel-based alloy specimen. The real and imaginary parts of the impedance at every position of the sensor computed by experiments and simulations were consistent with each other. Simulation results proved that the sensor was capable of detecting micro-defects with a size starting from 0.1 mm under the optimal excitation frequency of 0.8 MHz. It is not only sensitive to micro-cracks, but also it distinguishes the different crack sizes (length, width, anddepth).

자기차륜을 활용한 이송 장치의 공간 안정성과 제어

When the magnetic wheel facing a conductive plate is rotated at high speed, three-axis magnetic forces are generated. Among them, the levitation and lateral forces have self-stability and do not require a separate controller to be stable. In this study, we introduce a device that moves in space by controlling only the transfer position in a transport device comprising four magnetic wheels. The relationship between the design value of individual magnetic wheels and the range of spatial stability is explained using finite element analysis. In particular, the change in the levitation force according to the overlapping distance from the edge of the conductive plate to the center of the magnetic wheel is described using the induced current density. Because the only control variable in the developed system is the wheel speed, we present a simple logic and test results to transfer the system only by controlling the speed.

Low filler and highly conductive composite bipolar plates with synergistic segregated structure for enhanced proton exchange membrane fuel cell performance

The high conductivity of bipolar plate (BP) is crucial to the performance improvement of proton exchange membrane fuel cell (PEMFC). However, the traditional composite BP usually contain about 60–80 wt% conductive fillers, which will lead to poor mechanical strength and inferior processing performance. In this work, we manufactured a low filler and highly conductive PVDF-graphite-carbon black composite bipolar plates with synergistic segregated structure by structural design strategy, which can significantly improve the performance of PEMFC. The segregated PVDF-graphite-carbon black composite BP containing only 6 wt% carbon black and 34 wt% graphite exhibits an in-plane conductivity of 177.87 S/cm and area specific resistance of 9.30 mΩ∙cm2. The conductivity of the in-plane and through-plane is 256.78 and 9704.50 times higher than that of the composite BP with random dispersion of graphite and CB, respectively. The PEMFC single cell with the composite BP exhibits a maximum power density of 646.08 mW/cm2, which is much higher than that of conventional composite BP. Besides, the composite BP exhibit excellent flexural performance, hydrophobicity and satisfactory corrosion resistance. Therefore, the composite BP with segregated conductive network is a promising candidate for PEMFC.

A Further Theoretical Study of Capacitive Pressure Sensors Based on Thin Film Elastic Deflection and Parallel Plate Capacitor: Refined Closed-Form Solution and Numerical Calibration.

The capacitive pressure sensor based on thin film elastic deflection and a parallel plate capacitor uses a non-conductive elastic annular thin film centrally connected to a conductive, rigid, flat, concentric-circular thin plate as a pressure sensing unit. On application of pressure, the non-conductive thin film deflects elastically, which in turn moves the conductive thin plate (as a movable upper electrode plate of the parallel plate capacitor) towards the lower electrode plate, resulting in a change in the capacitance of the capacitor. Therefore, the applied pressure can be determined by measuring the capacitance change, based on the closed-form solution for the elastic behavior of the annular thin film under pressure. Such capacitive pressure sensors are more suitable for large-sized sensors such as those used for building-facade wind pressure measurements, etc. In this paper, a further theoretical study of such capacitive pressure sensors is presented. The newly presented, more refined closed-form solution can greatly reduce the output pressure error under the same input capacitance, in comparison with the previously presented closed-form solution. A numerical example of how to use the resulting closed-form solution to numerically calibrate input–output characteristics is given for the first time. The variation trend of pressure operation ranges and input–output characteristics with important parametric variations, which can be used for guiding the design of such capacitive pressure sensors, is investigated.

Determination of Steel Losses and Optimization of the Thickness of the Transformer Magnetic Conductor Sheets

Currently, transformer manufacturers are tasked with creating energy-efficient devices with a reduction of steel losses of up to 44 %. Appropriate theoretical developments are needed for its implementation. With a reduction of eddy-current losses, caused, for example, by reduction of decrease in the thickness of the magnetic conductor sheets, hysteresis losses simultaneously increase. A similar effect is caused by changing the size of the crystal grain of steel, thermomagnetic treatment and other technological impacts. In this regard, the exact determination of the components of total losses in steel is an urgent problem, the solution of which would minimize total losses. The article analyzes the expressions that determine the specific losses for eddy currents and hysteresis through the parameters of the magnetic circuit, and states that this technique is too complicated for engineering calculations. Since eddy current losses are proportional to the square of the frequency, and hysteresis losses are proportional to the frequency in the first degree, simple calculated expressions of eddy current and hysteresis losses have been obtained using the wattmetric method. Based on the fact that the dependence of the magnetization loss on the thickness of the magnetic conductor plates is a decreasing linear function, and the eddy current loss is an ascending parabolic function, an expression of the optimal thickness of the plates has been found, the implementation of which makes the losses of steel minimal. This information will make it possible to minimize total steel losses more effectively by varying the design parameters and the material of the magnetic conductor. It is shown that the charted idling losses of transformers manufactured by different manufacturers differ by more than 30 % and can be rounded and underestimated; therefore it is advisable to obtain this parameter as a result of an experiment (idling experiment).

Magnetoelastic nonlinear free vibration of an annular plate under a nonuniform magnetic field of the long straight current‐carrying wire

AbstractIn this article, the magnetoelastic nonlinear free vibration of a thin conductive annular plate under the nonuniform toroidal magnetic field is investigated, where the magnetic field is generated by a long straight current‐carrying wire. Based on electromagnetic theory, expressions of the nonuniform magnetic field, electromagnetic forces are deduced. The nonlinear free vibration equation of plate is derived by using the Hamilton principle. Considering different boundary conditions, the axisymmetric vibration differential equation is achieved by the Galerkin method. The method of multiple scales is employed to obtain the second‐order approximate analytical solutions and natural frequency. In numerical calculation, the characteristics of nonlinear natural vibration and singular points varying with different parameters, for example, current intensity and plate size, are presented, respectively. The results indicate that, with the increase of current, natural frequency increases and then stabilizes in the inner‐clamped and out‐free (C‐F) boundary, but decreases and stabilizes in the cases of the inner‐clamped and out‐clamped (C‐C) boundary or inner‐simply and out‐simply (S‐S) boundary. Moreover, when wire current is off, natural frequency maintains a constant, where the equilibrium solution of the system is a center. In addition, for all boundary conditions, natural frequency increases significantly with increase of internal radius and thickness, but decreases with the increase of outer radius.

Analysis of the Influence of Electrostatic Probe on Surface Charge Measurements

The electrostatic probe is among the most popular methods to measure the surface charge. However, the probe influences the surface charge distribution on the sample, which increases measurement error. In this paper, the electrostatic probe system is modeled to study its effect on surface charges on a circular conductor plate using electrostatic field calculation. The influence of the probe on the sample surface charges is found to increase with a decrease in the measurement distance, whereas it has a similar effect on surface charge density at different radial positions. A calibration process is proposed to measure the potential from the induced potential of the probe head. Using the measured potential, we calculate the surface charge density via the method of moments. The measurement error is analyzed when the measurement distance and number of rings are changed. The authors find that the number of rings should be appropriately reduced when the measurement distance increases to ensure the accuracy of the calculations. This research provides theoretical guidance for using the electrostatic probe and establishing a surface charge measurements system. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Design and Integration of Millimeter-Wave 5G and WLAN Antennas in Perfect Full-Screen Display Smartphones

Smartphone industries are seeking to maximize screen size, but a perfect full-screen phone is not yet available due to the unoccupied area required for the mobile antennas. Since a touchscreen is coated with transparent conductive layers, antennas below the touchscreen cannot create outward radiation. Accordingly, a non-metallic area is left for the antennas, which reduces the screen size. In this paper, we propose a design and integration of antennas for future millimeter-wave 5G smartphones to suit a perfect full-screen display. The proposed design consists of three modules, including a 1 × 12 patch antenna array at 28 GHz, a 1 × 8 patch array at 38 GHz, and a loop antenna at 2.45 GHz. The design environment consists of fully metallic top and bottom enclosures, mimicking the touchscreen and the printed circuit board, respectively. The three antennas were implemented on the flanks. Although the design area was limited and contained in parallel conductive plates, the three antennas still provided broad impedance bandwidths (26.5–32.0 GHz, 35.2–42.0 GHz, and 2.41–2.48 GHz) and high gains (16.7 dBi, 16.4 dBi, and 4.3 dBi). The isolation was larger than 20 dB, and the scanning ranges were ±45°. The proposed scheme is the first antenna system designed for perfect full-screen display phones.