Frequency Range Research Articles

Pseudo-Core-Shell Permalloy (Supermalloy)@ZnFe2O4 Powders and Spark Plasma Sintered Compacts Based on Mechanically Alloyed Powders.

Soft magnetic composite cores were produced by spark plasma sintering (SPS) from Ni3Fe@ZnFe2O4 and NiFeMo@ZnFe2O4 pseudo-core-shell powders. In the Fe-Ni alloys@ZnFe2O4 pseudo-core-shell composite powders, the core is a large nanocrystalline Permalloy or Supermalloy particle obtained by mechanical alloying, and the shell is a pseudo continuous layer of Zn ferrite particles. The pseudo-core-shell powders have been compacted by SPS at temperatures between 500-700 °C, with a holding time of 0 min. Several techniques were used for the characterisation of the powders and sintered compacts: X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, magnetic hysteresis measurements (DC and AC), and electrical resistivity. The electrical resistivity is stabilised at values of about 7 × 10-3 Ω·m for sintering temperatures between 600-700 °C and this value is three orders of magnitude higher than the electrical resistivity of sintered Fe compacts. The best relative initial permeability was obtained for the Supermalloy/ZnFe2O4 composite compacts sintered at 600 °C, which decreases linearly for the entire frequency range studied, from around 95 to 50. At a frequency of 2000 Hz, the power losses are smaller than 1.5 W/kg. At a frequency of 10 kHz, the power losses are larger, but they remain at a reduced level. In the case of Supermalloy/ZnFe2O4 composite compact SPS-ed at 700 °C, the specific power losses are even lower than 5 W/kg. The power losses' decomposition proved that intra-particle losses are the main type of losses.

A four-element metasurface loaded high gain MIMO antenna for X-band applications

This research presents a novel four-port metamaterial-backed Multiple Input Multiple Output (MIMO) antenna system designed for X-band applications. Each modified circular-shaped antenna element is meticulously printed on a 1.6 mm thick FR4 substrate, resonating within the 9.2 to 9.9 GHz frequency range, encompassing a significant portion of the X-band spectrum. To enhance overall gain, a tilted square-shaped 4 × 4-unit cell is strategically printed on the ground plane of the substrate. The proposed MIMO antenna achieves a maximum gain of up to 8 dBi across the operating spectrum, coupled with an impressive radiation efficiency of up to 80%. Fabrication of the designed antenna is performed, and comprehensive parameter measurements validate its performance, exhibiting a close correlation with simulated results. Essential MIMO parameters such as ECC (<0.01), TARC (>10 dB), CCL (<0.3), and diversity gain are calculated to affirm the antenna’s proficiency further. The results show that the proposed antenna could be a suitable contender for X-band applications.

Time Profile Study of Type III Solar Radio Bursts Using Parker Solar Probe

Solar type III radio bursts are crucial indicators of energetic electron activity in the solar corona and interplanetary space. Our assessment of 43 interplanetary type III bursts, recorded by the FIELDS instrument on board the Parker Solar Probe during Encounters 05 to 11, has led to significant and complex findings. We have analyzed time profile features across a frequency range of 19–0.5 MHz, revealing dependencies on frequency and providing insights into duration, burst speeds, bandwidths, and drift rates. This novel analysis has unveiled a spectral index of −0.63 ± 0.04 for rise, −0.69 ± 0.03 for decay time, and −0.68 ± 0.03 for the total duration. We have determined the average electron beam velocities for front, middle, and back as 0.15c, 0.13c, and 0.08c, respectively. Our findings show that faster electron beams generate emissions with shorter duration. The average ratio of the front-to-back velocity is 1.87, and the ratio of front-to-middle velocity is 1.23. We have also discovered a strong relationship between burst duration with rise, peak, and decay times, particularly pronounced with decay time (correlation coefficient = 0.95). This indicates that the entire temporal profile, including rise, peak, and decay phases, collectively contributes to event duration and is not solely influenced by external factors like plasma conditions or electron beam dynamics but also by internal burst processes. These complex findings shed light on the physical mechanisms governing burst dynamics, revealing intricate interactions between electron beam characteristics and observed temporal and spectral traits of type III solar radio bursts.

Machine learning model to predict rate constants for sonochemical degradation of organic pollutants

In this study, machine learning (ML) algorithms were employed to predict the pseudo-1st-order reaction rate constants for the sonochemical degradation of aqueous organic pollutants under various conditions. A total of 618 sets of data, including ultrasonic, solution, and pollutant characteristics, were collected from 89 previous studies. Considering the difference between the electrical power (Pele) and calorimetric power (Pcal), the collected data were divided into two groups: data with Pele and data with Pcal. Eight input variables, including frequency, power density, pH, temperature, initial concentration, solubility, vapor pressure, and octanol–water partition coefficient (Kow), and one target variable of the degradation rate constant, were selected for ML. Statistical analysis was conducted, and outliers were determined separately for the two groups. ML models, including random forest (RF), extreme gradient boosting (XGB), and light gradient boosting machine (LGB), were used to predict the pseudo-1st-order reaction rate constants for the removal of aqueous pollutants. The prediction performance of the ML models was evaluated using different metrics, including the root mean squared error (RMSE), mean absolute error (MAE), and R squared (R2). A significantly higher prediction performance was obtained using data without outliers and augmented data. Consequently, all the applied ML models could be used to predict the sonochemical degradation of aqueous pollutants, and the XGB model showed the highest accuracy in predicting the rate constants. In addition, the power density and frequency were the most influential factors among the eight input variables in prediction with the Shapley additive explanation (SHAP) values method. The degradation rate constants of the two pollutants over a wide frequency range (20–1,000 kHz) were predicted using the trained ML model (XGB) and the prediction results were analyzed.

Novel metamaterial array-based dual port MIMO antenna using low profile substrate with feature multiband, and high isolation for sub-6G, IoT, and WiMAX applications

This article represents a single-layered two-port MIMO antenna loaded into a compact plane-patterned metamaterial (MTM) structure for a 5G communication system. The antenna operates at three bands to investigate metamaterial properties in addition to diversity parameters, an arrangement of a series of arrays suggested a 2-port design antenna and a circular-shaped split ring resonator unit cell was developed. The design of a single port antenna utilizes 1 × 3 MTM unit cells for each component. This antenna operates within a frequency range ranging from 1 GHz to 15 GHz. Additionally, the suggested MIMO antenna offers a dominant isolation of –55dB. The measurement’s results show that, with an entire antenna size of 112 mm × 26.5 mm and a 3.33 GHz bandwidth, the MIMO antenna is achieved with good efficiency and CCL < 0.35, considerable DG > 9.97dB, ECC < 0.18, and TARC <–9.97. The presented design is suitable for medical imaging, RFID, Bluetooth, Wi-Fi, WiMAX, IOT, satellite communication systems, and the 5G and sub-6 GHz spectrum.

Exploration of room temperature magnetodielectric behavior in Nd0.5Dy0.5FeO3 thin films and transmission line resonators in GHz frequency range

This study explores the room-temperature magnetodielectric (MD) and magnetoresistance (MR) properties of Nd0.5Dy0.5FeO3 thin films on n-type silicon substrates from 4 Hz to 2 MHz. The observed MD effect registers a change of ∼23 %, and the MR effect manifests a change of ∼11 % when subjected to an applied magnetic field of 2.5 T at a frequency of 177 Hz. Interestingly, the MD effect was absent at 1 T across all frequencies. However, we observed an MR of 6 % at 1 T, implying the possibility of an intrinsic MD effect or the co-existence of both intrinsic and extrinsic contributions to the MD effect. To comprehensively gauge the dielectric properties of the thin film at higher frequencies, a 5-GHz microstripline resonator was fabricated. Coupled with experimental data and simulations, this study reveals a dielectric constant of ∼56 for the Nd0.5Dy0.5FeO3 thin film at 5 GHz and 300 K.

Slot-Loaded Vivaldi Antenna for Biomedical Microwave Imaging Applications: Influence of Design Parameters on Antenna's Dimensions and Performances.

This paper demonstrates the design steps of a slot-loaded Vivaldi antenna for biomedical microwave imaging applications, showing the influence of the design parameters on the antenna's dimensions and performances. Several antenna miniaturization techniques were taken into consideration during the design: reduction in the electromagnetic wavelength by using a high-permittivity substrate material (relative permittivity ϵr=10.2), the placement of the antenna inside a coupling medium (ϵr=23), and the elongation of the current path by etching slots on each side of the radiator to reduce the antenna's lowest resonant frequency without increasing its physical dimensions. Moreover, an analysis of different antenna slot design scenarios was performed considering different slot lengths, inclination angles, positions, and numbers. Considering the frequency range of microwave imaging (i.e., about 500 MHz-5 GHz) and the array arrangement typical of microwave imaging, the best design was chosen. Finally, the antenna was fabricated and its performances in the coupling medium were characterized. The simulation and measurement results showed good agreement between each other. In comparison with literature antennas, the one developed in this work shows wide bandwidth and compact dimensions.

Cellulose-reinforced foam-based phase change composites for multi-source driven energy storage and EMI shielding

To address the increasingly serious environmental pollution and energy crisis, there is an urgent need to develop multi-source-driven energy storage materials, the field of new energy sources, such as solar thermal power generation, but electromagnetic pollution has become a primary problem that needs urgent resolution. Therefore, the development of multifunctional phase change composites (CPCMs) with multi-source drive capabilities and excellent electromagnetic shielding integration is crucial. In this study, polypyrrole (PPy)-coated conductive fibers were crosslinked with polyvinyl alcohol (PVA) to form a three-dimensional network, which was then combined with metal foam to prepare Ni–F/PPy@CNF-PVA (PCN) dual-network carriers with high electrical conductivity by vacuum-assisted adsorption and freeze-drying methods. Polyethylene glycol (PEG) was subsequently encapsulated via vacuum impregnation to get the shape-stable PEG/Ni–F/PPy@CNF-PVA (PPCN) phase change composites. The PPCN exhibited good stability and high energy storage density (melt enthalpy up to 126.18 J/g, relative enthalpy efficiency over 99 %). Benefiting from its outstanding electrical conductivity (186680 S/m for PPCN-3), light-absorbing properties, and magnetism, the PPCN also exhibits highly efficient photothermal, electrothermal, and magnetothermal conversion capabilities. The electromagnetic interference shielding efficiency reaches up to 110.37 dB within the X-band frequency range (8.2–12.4 GHz). In conclusion, PPCNs are significant for multi-source-driven energy storage and electromagnetic shielding.

Screw transmission structure based triboelectric–electromagnetic hybridized generator for efficiently harvesting energy from a single mechanical stimulation

Among various electromechanical conversion technologies, the triboelectric-electromagnetic hybrid generator (TEHG) stands out with its capacity to operate across a wider frequency range. Nevertheless, extracting more electricity from a single mechanical stimulation remains a significant challenge. In this work, we propose a screw transmission structure based TEHG (ST-TEHG) that converts the contact-separation motion into continuous rotation. This transformation enables the device to produce multiple pulse outputs in both compression and rebound processes. Specifically, the threaded barrel is designed to rotate continuously under the action of the pressing lever. Excess energy is stored as elastic potential energy in the tower spring, which then initiates the threaded barrel’s reverse rotation upon the release of external force. Through systematical optimization of the screw transmission structure and device’s performances, ST-TEHG achieves an energy utilization efficiency that is 70.86 times than the device with conventional contact-separation mode in an operating cycle. The developed ST-TEHG demonstrates promising applications in smart factories for indoor conditions monitoring, such as temperature and humidity, assembly line monitoring, and hazardous zones warning. This screw transmission structure sets a precedent for highly efficient mechanical energy harvesting, propelling the practical advancement of hybrid generators.

Synthesis of polymeric carbon-based nanocomposites for electromagnetic shielding

In artificial intelligent retrieval, the evolution of smart electronic devices and wireless communication is a source of electromagnetic pollution (EMP), which is a severe global concern. Nowadays, conductive polymeric nanocomposites are exceptionally desirable for electromagnetic interference shielding (EMI) applications due to their good conductive and unique shielding properties. The aim of the present work is to study the EMI shielding effectiveness of thin films. For this purpose, we have synthesized PVA-based nanocomposite films. Reduced graphene oxide (rGO), and iron oxide nanoparticles were used as nanofillers. Nanoparticles of iron oxide were synthesized by the co-precipitation method, whereas rGO was synthesized by modified Hummer’s method. XRD (X-ray diffraction), FTIR (Fourier transform infrared) spectroscopy, (RBS), Rutherford backscattering spectroscopy, Current–Voltage (IV) measurements and Impedance spectroscopy were used for the characterization of nanocomposites, 3.5 dB, for iron oxide/PVA thin films at 12 GHz frequency range. rGO/PVA thin films with 0.125, 0.25 and 0.5 wt% were 4.2, 8.2 and 12.3 dB, respectively, at 12 GHz range. Such shielding materials have useful applications in military field and radar systems. These shielding films can be used to protect the electronic instruments from the light waves striking them. Its use also limits health hazards to the people living in extremely radiative environments.

Injectable Carrageenan/Green Graphene Oxide Hydrogel: A Comprehensive Analysis of Mechanical, Rheological, and Biocompatibility Properties.

In this work, physically crosslinked injectable hydrogels based on carrageenan, locust bean gum, and gelatin, and mechanically nano-reinforced with green graphene oxide (GO), were developed to address the challenge of finding materials with a good balance between injectability and mechanical properties. The effect of GO content on the rheological and mechanical properties, injectability, swelling behavior, and biocompatibility of the nanocomposite hydrogels was studied. The hydrogels' morphology, assessed by FE-SEM, showed a homogeneous porous architecture separated by thin walls for all the GO loadings investigated. The rheology measurements evidence that G' > G″ over the whole frequency range, indicating the dominant elastic nature of the hydrogels and the difference between G' over G″ depends on the GO content. The GO incorporation into the biopolymer network enhanced the mechanical properties (ca. 20%) without appreciable change in the injectability of the nanocomposite hydrogels, demonstrating the success of the approach described in this work. In addition, the injectable hydrogels with GO loadings ≤0.05% w/v exhibit negligible toxicity for 3T3-L1 fibroblasts. However, it is noted that loadings over 0.25% w/v may affect the cell proliferation rate. Therefore, the nano-reinforced injectable hybrid hydrogels reported here, developed with a fully sustainable approach, have a promising future as potential materials for use in tissue repair.

Dispersion of thermoelastic guided waves in multi-layered porous media

The mechanical properties of the graphite electrode will dynamically change during the charge-discharge cycle, which will affect the propagation characteristics of guided waves in lithium-ion batteries. Meanwhile, lithium-ion batteries experience fluctuations in operating temperature during cycling, which will also influence the propagation of guided waves. This research aims to investigate the guided wave propagation problem of porous electrode material with electrolyte versus temperature. The problem is under the framework of Green-Naghdi theory and Biot theory, and a numerical approach is presented to solve the thermoelastic wave propagation characteristics in such a multi-layered porous electrode. A frequency domain simulation for a multi-layered porous anode will be established. The simulation results confirm the feasibility and accuracy of the proposed approach. The porosity of the anode material shows obvious dynamic variation during cycling, which illustrates a strong correlation with the elastic modulus of the solid skeleton. Then, the effects of porosity and temperature variations on the propagation characteristics of thermoelastic guided waves in multi-layered porous graphite electrodes will be analyzed in detail. The phase velocity of fundamental modes appears regularly shift in the low frequency range. This may provide theoretical support for the acoustic nondestructive characterization of the operating states of the lithium-ion batteries.

Low-Cost and Paper-Based Micro-Electromechanical Systems Sensor for the Vibration Monitoring of Shield Cutters.

Vibration sensors are widely used in many fields like industry, agriculture, military, medicine, environment, etc. However, due to the speedy upgrading, most sensors composed of rigid or even toxic materials cause pollution to the environment and give rise to an increased amount of electronic waste. To meet the requirement of green electronics, biodegradable materials are advocated to be used to develop vibration sensors. Herein, a vibration sensor is reported based on a strategy of pencil-drawing graphite on paper. Specifically, a repeated pencil-drawing process is carried out on paper with a zigzag-shaped framework and parallel microgrooves, to form a graphite coating, thus serving as a functional conductive layer for electromechanical signal conversion. To enhance the sensor's sensitivity to vibration, a mass is loaded in the center of the paper, so that higher oscillation amplitude could happen under vibrational excitation. In so doing, the paper-based sensor can respond to vibrations with a wide frequency range from 5 Hz to 1 kHz, and vibrations with a maximum acceleration of 10 g. The results demonstrate that the sensor can not only be utilized for monitoring vibrations generated by the knuckle-knocking of plastic plates or objects falling down but also can be used to detect vibration in areas such as the shield cut head to assess the working conditions of machinery. The paper-based MEMS vibration sensor exhibits merits like easy fabrication, low cost, and being environmentally friendly, which indicates its great application potential in vibration monitoring fields.

Reconstruction of the Permittivity of Ex Vivo Animal Tissues in the Frequency Range 1-20 GHz Using a Water-Based Dielectric Model.

Several medical techniques are based on the application of electromagnetic fields (EMFs) on the human body with therapeutic and/or diagnostic aims. The response of human tissues to the applied EMF is mediated by the tissues' dielectric properties, which must therefore be characterized at the frequencies of the considered technique. Due to the heterogeneity and complexity of biological tissues, it is necessary to know their properties in vivo for the specific condition of interest. Traditional techniques for the dielectric characterization of biological tissues are invasive and, as such, not adoptable for this aim. Accordingly, alternative sensors and/or sensing methods are needed. Recently, a new wideband spectroscopy technique was proposed, based on quantities derived from the Magnetic Resonance (MRI) signal. Among these quantities, the water content was proposed to evaluate the dielectric properties at frequencies around a few GHz. This work verifies the possibility of deriving tissues' dielectric properties in the frequency range of 1-20 GHz based on knowledge of the water content. The water content was retrieved through a dehydration procedure for five different ex vivo tissues. The achieved results were compared with references from the literature.

An ultra broadband metamaterial absorber based on metal-dielectric-metal technology for THz spectrum

This paper introduces a novel ultra-broadband Metamaterial Absorber (UBMA) demonstrating significant absorption capabilities across a wide terahertz frequency range from 2.42 THz to 6.11 THz. The 3.7 THz bandwidth represents 87% of the central frequency. The proposed UBMA comprises three layers: a star-shaped metal patch on top, a dielectric substrate in the middle, and a metallic ground plane below. Simulations using CST Microwave Studio software reveal that the design achieves high absorption at five distinct frequencies: 2.47, 3.45, 4.89, 6.01, and 6.87 THz, with absorption rates of 99% for the first four peaks and 90% for the fifth peak. The study of electric field and surface current distribution provides insights into the absorption mechanism. While the UBMA exhibits polarization-independent performance, its angular response shows some sensitivity to the incident angle, especially beyond 30° Despite this, the absorber maintains over 70% absorptivity up to a 45° incidence angle for both TE and TM polarizations within specific frequency ranges. The simple structure combined with high absorption efficiency makes the UBMA suitable for THz imaging, detection, and stealth applications, although its angular sensitivity must be considered for certain applications.

Investigation of the vibration isolation effect of composite vibration isolation walls on ground surface vibrations in deep tunnels of suburban railways

To investigate the vibration isolation effect of composite vibration isolation walls on surface vibrations in suburban railway deep tunnels under various influencing factors, an integrated numerical model of the train was initially developed. This model solved the wheel-rail interaction force and was applied to a three-dimensional volume coupling model of the track soil. Subsequently, the model's reliability was validated through comparison with measured data. Afterward, the vibration isolation effects of various types of EPS material vibration isolation walls were examined, with a focus on exploring the impact of thickness, material proportion, and relative positioning of the materials within the vibration isolation wall composed of EPS material and concrete. Research indicates that with an increase in the burial depth of a single material vibration isolation wall, its effective vibration isolation frequency range gradually widens. When the burial depth of the vibration isolation wall exceeds the tunnel burial depth, the vibration isolation effect is optimal. Composite vibration isolation walls, with thicknesses smaller than single-material vibration isolation walls, exhibit superior vibration isolation effects compared to their single-material counterparts. The effective vibration isolation frequency band of composite vibration isolation walls differs from that of single-material vibration isolation walls. Using the optimal-size vibration isolation wall of a single material as a composite vibration isolation wall enhances the vibration isolation effect of peak acceleration in the frequency domain by 16.58% and peak velocity by 16.95%. Moreover, frequency domain peak displacement experiences a 30.73% improvement in the vibration isolation effect.

Spectral and conductivity measurements insights on loading mechanisms of DMSO/water-kaolin complexes

Kaolin, a naturally occurring clay mineral renowned for its distinctive properties, holds significant importance across various industries. The integration of dimethyl sulfoxide (DMSO) into kaolin matrices, both in the presence and absence of water, has been extensively explored for its potential to enhance material characteristics. Addressing debates surrounding the proposed adsorption mechanism for the type I structure of DMSO, this study undertook a comprehensive physicochemical characterization of DMSO-kaolin complexes (DMSO-KCs) derived from untreated (UnK) and HCl-treated (HK) Egyptian ore, with a focus on elucidating the loading mechanism facilitated by water.Key insights gleaned from electrical conductivity, dielectric constant, and Fine Testing Technology – Fourier-transform infrared (FTT-FTIR) measurements, shedding light on the bonding nature of DMSO-KCs. FTT-FTIR analysis revealed two stages of water departure at 180 °C, with the final stage coinciding with the release of pyrolysis gases, confirming the catalytic degradation of DMSO. Through X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA), two distinct bonding types of DMSO molecules with kaolinite were identified: amorphous adsorbed (type I) and lattice-oriented intercalated (type II).Electrical characteristic evaluations within the temperature range of room temperature (RT) to 260 °C and frequency range of 42 Hz–1 MHz revealed that DMSO intercalation enhances the electrical properties of kaolin. Hydrated DMSO-KCs exhibited higher values of σac and ɛʹ compared to non-hydrated samples. The activation energy (Ea) values for HCl-treated samples were smaller than those of untreated ones. Alternating current (AC) conductivity analysis indicated predominantly ionic behavior with frequency and temperature dependency in both HCl-treated and untreated kaolin. Our findings substantiate the adsorption mechanism of Type I DMSO, highlighting its amorphous nature, instability, and catalytic degradation over time, in contrast to the intercalated type II. This elucidation is pivotal for understanding the behavior of DMSO-KCs across diverse applications, including electronics, ceramics, and materialsscience.

Enhancement and modulation of near-field radiative heat transfer in Bi2Se3/graphene-based three-body configurations

The manipulation of near-field radiative heat transfer (NFRHT) through complex photon tunneling in many-body systems has garnered significant attention, particularly for advancing thermal management in micro- and nanodevices. In this work, we theoretically investigate the enhancement and modulation of NFRHT within a graphene/Bi2Se3-based three-body configuration. Compared to a two-body configuration, the three-body modulator enhances the near-field radiative heat flux (NFRHF) by 2.77, primarily due to the enhancement of surface plasmon polaritons facilitated by graphene. Moreover, we analyze how NFRHF is modulated by varying the vacuum gap between the emitter and the intermediate, adjusting the thickness of Bi2Se3 films in emitter and intermediate, as well as manipulating the chemical potentials of graphene. Results indicate that by tuning the chemical potentials of graphene, thermal regulation can be enhanced up to a ratio of 2.55. This enhancement is attributed to the excitation of SPPs, which are concentrated in a narrower wave vector space and higher angular frequency range as the chemical potential of graphene increases. These findings have implications for controlling thermal radiation applications utilizing graphene and Bi2Se3 heterostructures. This work demonstrates the superiority of the three-body system in enhancing NFRHT and contributes new insights into the potential applications of Bi2Se3 in NFRHT.

A nonlinear vibration isolator with an essentially nonlinear converter

This paper introduces nonlinearity into bilinear springs and proposes an efficient asymmetrical nonlinear frequency converter (NC) that has a non-reciprocal transmission, which cascades a nonlinear spring and a rope. To solve the vibration equations of both NC and the conventional NES, the Runge-Kutta method is utilized. A comparison is conducted between the amplitude attenuation rates of the NC and the conventional NES. The rate of energy dissipation is indicated by analyzing the remaining energy. According to numerical analysis results, NC has a better performance in suppressing vibration than the conventional NES within a certain range. The energy dissipation rate is higher under a wide initial condition. In addition, NC can cause energy to shift from low-frequency regions to high-frequency regions with wide frequency bands. NC has a broader frequency range and a wider range of applications. This research offers a new approach and strategy for exploring effective devices for damping vibrations.

Real-time monitoring the formation of polymer double network for gel polymer electrolyte by means of dielectric spectroscopy

A non-destructive method of detecting the internal information of the system is attempted in a polymer double network for gel polymer electrolyte in lithium-ion battery. The real-time monitoring for polymerization of 1,3-dioxolane (DOL) and cross-linking of cyanoethyl poly(vinyl alcohol) (PVA-CN) is carried out in a coin cell at 0–80 ℃ by means of dielectric spectrum. A widely distributed dielectric relaxation varying with monitoring time and temperature is observed in the frequency range of 3–103 kHz, and the relaxation parameters of the three sub-relaxations are obtained by fitting the dielectric spectrum with the HN equation. It is found that the relaxation intensity Δε and relaxation time τ are obviously dependent on the monitoring time and temperature: Δε and τ change obviously near the respective gel points of DOL and PVA-CN (DOL at 25 ℃, PVA-CN at 60 ℃), suggesting gelation at two gel points respectively. The different structural changes of the system before and after gelling temperature are speculated, and the possible microstructure of the system in each temperature range is proposed after analyzing the relaxation parameters. The applicability of the real-time dielectric monitoring in the study of the structure of gel polymer electrolytes is preliminarily concluded.