Changes In Electrical Parameters Research Articles

Pressure-directed enhanced ionic conductivity in MgMoO4 mixed-phases

The mixed conductors have attracted much attention for potential applications in fuel cells, sensors, supercapacitors. Here, the electrical transport behavior of MgMoO4 were systematically investigated at pressures up to 30.0 GPa using impedance spectroscopy measurements and theoretical calculations. The discontinuous changes in electrical parameters reflect the pressure-induced phase transition from β-MgMoO4 to γ-MgMoO4. The transport mechanism was determined to be mixed ionic-electronic conduction, and the contributions of carriers were distinguished. In the pressure range where the low- and high- pressure phase coexist, ionic transport plays a dominant role. The optimal solution for ionic conductivity of MgMoO4 occurs in the mixed phases, and the ionic conductivity has been increased by two orders of magnitude in comparison to that observed at ambient conditions. The resistances were analyzed with band gap, transference number and the relative ionic diffusion coefficient. The pressure constrains the atomic amplitude and limits ion-phonon scattering, resulting in a significant enhancement of the ionic diffusion coefficient and facilitates the ionic conduction of γ-MgMoO4. Meanwhile, it is found that the grain boundary response was weakened under compression, and the static dielectric constant was improved by pressure. These results offer valuable insights for optimizing and applying ABO4-based mixed conductors.

Hierarchical aggregation structure regulation and electromagnetic loss mechanism of cross-linked polyaniline in polymer wave absorbers

Frequency-specific electromagnetic wave absorbent materials are a key solution to the problem of multi-band electromagnetic pollution. Traditional absorbent materials often exhibit abrupt changes in electrical parameters due to factors such as threshold over-permeation. Few studies have established a strong correlation between the microscopic structure of these materials and their effective absorption frequency (EAF) ranges, making precise linear control difficult. Therefore, it is essential to explore new absorbent materials with adjustable structures closely linked to their electrical parameters. In this work, we focused on easily modifiable conductive polymer composites, producing a series of polymer-magnetic oxide absorbing materials with crosslinking degrees and magnetic properties that can be linearly adjusted. By optimizing their microstructure, we enhanced their impedance matching capabilities. Ultimately, we developed an efficient absorbent material with tunable absorption effects, specifically, the P-1.0Co3O4 sample achieved an effective absorption bandwidth of 6.64 GHz at a thickness of only 1.3 mm, with tunable EAF ranging from 10.9 GHz to 18.0 GHz. While full-band adjustability was not realized, this work provides significant theoretical guidance and engineering application value for developing band-specific absorbent materials.

Evaluation of Electrical Model Parameter Changes in SiC Power MOSFETs During Power Cycling Test

Evaluation of Electrical Model Parameter Changes in SiC Power MOSFETs During Power Cycling Test

Changes in electrical parameters of the heart in an experimental model of malignant tumor growth during of hyperthyroidism

Experimental and clinical studies demonstrate the possibility of modulating the development of malignant tumors in thyroid imbalance, in particular hyperthyroidism, which negatively affects the electrophysiology of the heart. In an experimental model of tumor growth during of hyperthyroidism, activation of the tumor was shown.Aim: To study electrophysiological parameters of the mouse heart at the initial stages of transplantable tumor growth during of hyperthyroidism.Material and Methods. In female mice of the C57BL/6 line (n = 20) was created a model of melanoma B16/F10 growth during of hyperthyroidism, which was induced by daily intraperitoneal administration of liothyronine sodium (T3) for a long time and confirmed by determining the content of thyroid-stimulating hormone and triiodothyronine in the blood using the radioimmune method. On the 5th day of T3 administration, the melanoma was transplanted. ECG was recorded non-invasively (ecgTUN- NEL, ecgAVG software, emka TECHNOLOGIES, France) on the 1st and 3rd days of T3 administration, in groups with a tumor – on the 6th day after its transplantation.Results. Pathological changes were revealed: in the group with hyperthyroidism – rhythm irregularity, decrease the amplitude of P and T below the isoline, widening of the QRS, on the 3rd day – the death of 1 mouse was noted due to large-focal myocardial infarction; in the group with melanoma – only sinus arrhythmia and decreased heart rate; in the group with a combination of pathologies – an almost normal ECG, with the exception of an increase in P amplitude and a slight increase in QRS.Conclusion. Already in the early stages of hyperthyroidism or tumor growth, there was a violation of myocardial depolarization/ repolarization processes, capable of causing even death of the animal. In case of comorbidity, the majority of ECG parameters normalized, indicating the inclusion of compensatory mechanisms in the interaction of pathologies. The results demonstrate the need for a deeper study of the mechanisms of interaction of several simultaneously existing pathologies in the body.

Feasibility of a Cardiac Magnetic Resonance Protocol for "off-on" Cardiac Resynchronization Therapy Evaluation.

Cardiac resynchronization therapy (CRT) is a standard treatment for patients with heart failure and electrical dyssynchrony. Cardiac magnetic resonance (CMR) is the gold standard for assessing left ventricular (LV) function. However, the feasibility of using CMR with active CRT is still uncertain. To assess the feasibility of a CRT "off-on" protocol during CMR and measure the acute effects of CRT interruption on LV function. Patients underwent CMR before (pre-CRT) and 6 months after (post-CRT) an MR-conditional CRT defibrillator implantation. The post-CRT scan included two complete sets of cine images, one with inactive (post-CRTOFF) and one with active CRT (post-CRTON), maintaining a continuous connection between device and programmer. Out of 29 enrolled patients, 8 (28%) had complete and analyzable post-CRT data. Unsuccessful procedures were attributed to connection problems between the CRT device and the programmer (n = 10), poor image quality (n = 7), and lack of patient cooperation (n = 4). LV ejection fraction significantly increased between pre-CRT scan (28.1%) and both post-CRTOFF (37.9%; p = 0.046) and post-CRTON CMR (35.0%; p = 0.037), with a nonstatistically significant trend toward decreased LV volumes. No adverse events or significant changes in device electrical parameters (including battery level) were detected during the post-CMR scan period. A CRT "off-on" protocol during CMR studies can be safely executed in patients with an MR-conditional CRT defibrillator. However, technical improvements are needed to facilitate high-quality scans during active CRT. Favorable changes in LV function induced by CRT remodeling were not acutely reversed with the interruption of electrical therapy.

Long-distance transmission conductor condition sensing based on distributed fiber optic sensing technology

Abstract The existing long-distance transmission line perception mainly focuses on the measurement and analysis of electrical parameters. When the line is subject to wind vibration, icing or galloping, the changes of electrical parameters are not obvious and difficult to capture, resulting in poor performance of long-distance transmission line fault state perception. In this regard, the long-distance transmission line condition sensing based on distributed optical fiber sensing technology is studied. This method designs corresponding sensing methods for four working conditions: using the back Brillouin scattering sensor and phase sensitive Rayleigh scattering sensor in the optical fiber sensing technology to form a multi parameter distributed optical fiber sensing device, which is used to sense the surface temperature, vibration, strain and other data of the long-distance transmission line; By analyzing the linear relationship between fiber Brillouin frequency shift and Brillouin power and fiber strain and temperature, the sensing results of icing thickness of long-distance transmission lines are obtained; By calculating the amplitude and phase information of the detection signal, the sensing results of long-distance transmission line vibration are obtained; By calculating the time difference of polarization mutation signal at both ends of long-distance transmission line, combined with the propagation speed of optical signal and the length of long-distance transmission line, the perception result of lightning fault location of long-distance transmission line can be obtained. The experimental results show that this method can more accurately collect the real-time operation data of long-distance transmission lines, and can effectively perceive the galloping, wind vibration and lightning fault location of long-distance transmission lines.

Effect of fruit ripeness on electrical impedance spectrum parameters

This study aimed to reveal the mechanisms underlying changes in the electrical parameters of fruit during ripening. Plums and blueberries were selected as research objects, and their electrical parameters, firmness, water state, and microstructure with different maturities were measured. The observed relationships between fruit ripeness and electrical parameters were as follows: as fruit ripeness increased, the cell structure loosened, the number of gaps increased, membrane permeability increased, the distribution of free water became more scattered, and firmness gradually decreased. These factors led to increased cell fluid fluidity, shorter current flow paths, and lower impedance values. This study reveals the changes in various physiological indicators and electrical parameters of fruits during ripening and provides theoretical support for detecting fruit maturity using electrical parameters. These results are significant for the detection and grading of fruit maturity, extending the fruit preservation period, and developing rational fruit storage strategies.

Suppression of irradiation effect on electrical properties of silicon diodes by iron in p-silicon

Radiation-hardness of silicon (Si) has been the subject of interest due to the damage of the material-based detectors during and after operation. In this work, the effects of 4 MeV proton-irradiation on the electrical properties of devices fabricated on undoped and Fe-doped p-Si were investigated using current-voltage (I-V) and capacitance-voltage (C-V) techniques. A decrease in current and capacitance is less pronounced and the conduction mechanism remains unchanged on Fe-doped p-Si diode after proton-irradiation. This insignificant change of electrical parameters of the Fe-doped diode after proton-irradiation indicates the suppression of the radiation effect by Fe in Si. The electrical properties of the diode are less dependent on incident radiation, because of the possible prevention of further dislodgement of atoms by incident radiation. As a result, the material becomes resistant to radiation damage, making the electrical properties of the diode independent of incident radiation due to Fe atoms in Si. As a result of the ohmic behaviour displayed by the Fe-doped Si diode, it is possible that in Si, Fe is responsible for generation-recombination (g-r) centres, which are defect levels positioned at the middle of the energy gap of Si. The possibility of these defects being responsible for the suppression of the radiation effect is explained in this work, making Fe a promising dopant to improve the radiation-hardness of Si.

Influence of 700 keV O3+ ion implantation on current transport properties of Cr/p-GaN SBD’s

In the present study we show a detailed investigation into the influence of 700 keV O3+ ion implantation in Cr/p-GaN SBDs on electrical characteristics / current transport properties. Also the damage events along the trajectory of the ion beam were quantitatively estimated through SRIM and TRIM simulations. The Current-voltage (I-V) characteristics were analyzed using different methods such as Cheung and Cheung's method and Norde’s method to obtain different electrical parameters. The values of n and ϕB decrease up to a fluence of 1 × 1014 ions cm−2, and show a fractional increase at a fluence of 1 × 1015 ions cm−2. Further, a drastic increase in values of series resistance (RS ) of SBDs with an increase in fluence was observed. In the forward-bias voltage regions, the Cr/p-GaN SBDs conduction mechanism shows an increasingly ohmic behavior with an increase in fluence, which may be attributed to thermally generated carriers. At low voltage, the reverse current conduction mechanism is due to Poole-Frenkel emission. For the high voltage region, Schottky emission mechanism becomes more prominent. The changes in electrical parameters are closely related to the defect and damage profiles estimated through SRIM/TRIM simulations, which are strongly dependent on the dose of the 700 keV O3+ ion implantation. Additionally, we found that at high doses, the charge transport mechanism changes, with additional defects affecting not only the thermionic emission mechanism but also various current transport mechanisms.

Effect of hydrogen treatment on 4H-SiC Schottky barrier diodes

In this letter, 4H-SiC Schottky barrier diodes (SBDs) with Ti Schottky metal have been subjected to hydrogen treatment in a confined environment of 4% H2 and 96% N2 at 150 °C. The effect of hydrogen treatment on the SBDs electrical characteristics has been investigated by technical computer-aided design simulation (TCAD) and power device analyzer curve tracer. The change of electrical parameters of SBDs measured after hydrogen treatment is studied in detail, and the related degradation mechanism is discussed. It was found that hydrogen treatment affected both the interface region and bulk region of SiC SBDs. After hydrogen treatment, the Schottky barrier increases slightly, the ideal factor (n) decreases slightly, and the interfacial state density (D it) decreases. Hydrogen treatment resulted in a slight reduction in specific on-resistance (R on-sp), which was attributed to the diffusion of H in SBDs. Through TCAD simulation, it is determined that the diffusion of H in the body diode of SBDs is the main reason for the degradation of high forward current and high reverse voltage characteristics.

Control Strategy of Flywheel Energy Storage System for Improved Model Reference Adaptive System Based on Tent-Sparrow Search Algorithm

This study addresses speed sensor aging and electrical parameter variations caused by prolonged operation and environmental factors in flywheel energy storage systems (FESSs). A model reference adaptive system (MRAS) flywheel speed observer with parameter identification capabilities is proposed to replace traditional speed sensors. The proposed method uses reference and adjustable models to identify the stator resistance and permanent magnet flux (PM Flux) to mitigate the adverse effects of electrical parameter changes on control performance. The Tent chaotic mapping-improved Sparrow Search Algorithm (SSA) optimizes the Proportional-Integral (PI) controller parameters for the dual closed-loop and MRAS speed adaptation laws of the flywheel motor. Moreover, a self-switching parameter identification (SSPI) scheme, which constructs a cost function based on the current, parameter identification, and speed errors, is proposed to prevent inaccuracies in parameter identification. The MRAS observer selects the appropriate PI adaptive mechanism based on the error values, thereby enhancing identification accuracy. Simulink simulations show significant improvements in the rapidity and accuracy of the Tent-SSA optimized MRAS flywheel speed observer, enhancing the stability and robustness of the flywheel rotor. Experimental validation on a constructed FESS platform confirms the feasibility of this method.

Real-time monitoring method for power system voltage based on optical voltage sensors

Abstract A real-time monitoring method for power system voltage based on optical voltage sensors is proposed to obtain transient voltage signals and achieve real-time tracking of instantaneous changes in electrical parameters of the power system accurately and effectively. Analyzing the topology principle of power system transformers clarifies the installation location of optical voltage sensors. By combining the measurement principle of optical voltage sensors, the electrical, optical modulation, and optical-electrical conversion of voltage signals are achieved, and the voltage signal of the power system is output. Using the short-time Fourier transform method to perform temporal processing on the output signal and obtaining a voltage signal sliding window based on wavelet packet decomposition, we set the normal range threshold of the voltage signal in the sliding window, combined with information entropy theory to extract key features of the voltage signal and achieve real-time monitoring of the power system voltage. The experimental results show that the proposed method can effectively obtain transient voltage signals of the power system, with an average detection accuracy of 92.61%, and the output voltage can be adjusted promptly to reflect the instantaneous changes in the power system voltage.

Impact of an interrupted mechanical deformation on the electrical behavior of commercial lithium-ion pouch cells with varied aging histories for battery qualification

This study investigates the influence of non-critical mechanical deformations, i.e., without internal short circuit (ISC), on lithium-ion batteries and examines their correlation with changes in electrical parameters. Nine commercial 50 Ah NMC111/Graphite pouch cells with diverse aging histories were electrochemically cycled before and after a controlled mechanical deformation. The results revealed consistent alterations in electrical parameters after deformation, including state of health (SOH) upon discharging, Coulombic efficiency, constant current discharge time (CCDT), voltage relaxation profile (VRP) voltage, VRP slope, and Area VdQ. Morphological changes due to deformation affected the overall electrical cell behavior. The deformation-induced effects are attributed to electrolyte shifting and electrode cracking which leads to loss of active material (LAM), whereas the morphological changes directly contributed to increased internal resistance (IRI) and an increase in the heterogeneity of the current distribution over the electrode surface. Distinct effects were observed in different-aged cells, with non-electrically aged cells being more affected by the electrode cracking and the current imbalances increase. The study underscores the high importance of early detection of non-critical mechanical deformations for ensuring battery safety and makes valuable contributions to battery qualification and the assessment of second-life batteries.

Pulsed field ablation in patients with cardiac implantable electronic devices: an ex vivo assessment of safety.

Pulse field ablation (PFA) is a novel catheter ablation technology with potential safety benefits due to its tissue selectivity. It has the potential to directly damage or interact with the functionality of cardiac implantable electronic devices (CIEDs) in the form of electromagnetic interference (EMI). The aim of our study was to assess the impact of PFA on CIEDs. PFA lesions (45 per CIED) were applied from the Farapulse system to CIEDs (< 5 cm from the lead tip and < 15 cm from the generator). All devices were checked before and after PFA application for proper sensing and pacing functionality as well as for integrity of shock circuits in ICDs using a heart simulator. Moreover, devices were then interrogated for any spontaneous reprogramming, mode switching or other EMI effects. In total, 44 CIEDs were tested (16 pacemaker, 21 ICDs, 7 CRT-P/D) with 1980 PFA applications. There was no change in device settings, functionality and electrical parameters, and there was no macroscopic damage to the devices. The risk of damage to the electric components or leads on a patient-based analysis is 0/44 (95% CI 0-8%) and on a PFA pulse-based analysis is 0/1980 (95% CI 0-0.2%). Clinically relevant EMI appeared with oversensing and pacing inhibition but not tachycardia detection. Bipolar PFA appears safe and does not result in damage to CIEDs or leads. Clinically relevant EMI does occur, but appropriate peri-procedural programming may mitigate this. In vivo studies are needed to confirm our findings.

Microwave biosensor for the detection of growth inhibition of human liver cancer cells at different concentrations of chemotherapeutic drug.

Cytotoxicity assays are crucial for assessing the efficacy of drugs in killing cancer cells and determining their potential therapeutic value. Measurement of the effect of drug concentration, which is an influence factor on cytotoxicity, is of great importance. This paper proposes a cytotoxicity assay using microwave sensors in an end-point approach based on the detection of the number of live cells for the first time. In contrast to optical methods like fluorescent labeling, this research uses a resonator-type microwave biosensor to evaluate the effects of drug concentrations on cytotoxicity by monitoring electrical parameter changes due to varying cell densities. Initially, the feasibility of treating cells with ultrapure water for cell counting by a microwave biosensor is confirmed. Subsequently, inhibition curves generated by both the CCK-8 method and the new microwave biosensor for various drug concentrations were compared and found to be congruent. This agreement supports the potential of microwave-based methods to quantify cell growth inhibition by drug concentrations.

Study on Radiation Damage of Silicon Solar Cell Electrical Parameters by Nanosecond Pulse Laser

This experimental study investigates the damage effects of nanosecond pulse laser irradiation on silicon solar cells. It encompasses the analysis of transient pulse signal waveform characteristics at the cells’ output and changes in electrical parameters, such as I–V curves before and after laser irradiation under varying laser fluence and background light intensities, and explores the underlying action mechanisms of laser irradiation. The study reveals that as the laser fluence increases up to 4.0 J/cm2, the peak value of the transient pulse signal increases by 47.5%, while the pulse width augments by 88.2% compared to the initial transient pulse signal. Furthermore, certain parameters, such as open-circuit voltage, short-circuit current, and peak power obtained, from the measured I–V curve indicate a threshold laser fluence for functional degradation of the solar cell at approximately 1.18 ± 0.42 J/cm2. Results obtained from laser irradiation under different background light intensities underscore the significant influence of background light on laser irradiation of silicon cells, with the most severe damage occurring in the absence of light. Moreover, findings from laser irradiation at multiple locations on the silicon cell demonstrate a linear decrease in the output voltage of the silicon cell with an increase in the number of irradiation points.

A rapid detection method for diesel content in diesel-contaminated soil based on dielectric measurement and oven-drying tests

Geophysical testing techniques have been successfully applied to identify light non-aqueous phase liquids in soils, but challenges remain in rapidly detecting contaminant content. Detection of contaminants in soil using geophysical testing techniques relies on sensors sensitive to electrical and electromagnetic parameter changes. In this study, the complex permittivity of silty clay contaminated with 0# diesel was measured using an open-ended coaxial probe at frequencies from 200–3000 MHz, and the four-phase dielectric mixing models were evaluated. The measurement results showed that the complex refractive index method (CRIM) model provided a better match with the real permittivity of the four-phase system between 500–3000 MHz with relative errors within an acceptable range of 4%. To eliminate the unknown variable in the CRIM model, an improved equation for the relationship between water content and diesel content of the watery diesel-contaminated silty clay was established by the oven-drying method. Thus, a method for the rapid quantitative detection of the diesel content in contaminated soil has been developed based on dielectric measurement and oven-drying tests. The relative error between the calculated and actual set diesel content for ten manually configured diesel-contaminated soil samples was within 10%, with a maximum error of 15.75%.

Real-Time Detection of Yeast Growth on Solid Medium through Passive Microresonator Biosensor.

This study presents a biosensor fabricated based on integrated passive device (IPD) technology to measure microbial growth on solid media in real-time. Yeast (Pichia pastoris, strain GS115) is used as a model organism to demonstrate biosensor performance. The biosensor comprises an interdigital capacitor in the center with a helical inductive structure surrounding it. Additionally, 12 air bridges are added to the capacitor to increase the strength of the electric field radiated by the biosensor at the same height. Feasibility is verified by using a capacitive biosensor, and the change in capacitance values during the capacitance detection process with the growth of yeast indicates that the growth of yeast can induce changes in electrical parameters. The proposed IPD-based biosensor is used to measure yeast drop-added on a 3 mm medium for 100 h at an operating frequency of 1.84 GHz. The resonant amplitude of the biosensor varies continuously from 24 to 72 h due to the change in colony height during vertical growth of the yeast, with a maximum change of 0.21 dB. The overall measurement results also fit well with the Gompertz curve. The change in resonant amplitude between 24 and 72 h is then analyzed and reveals a linear relationship with time with a coefficient of determination of 0.9844, indicating that the biosensor is suitable for monitoring yeast growth. Thus, the proposed biosensor is proved to have potential in the field of microbial proliferation detection.

Single-event burnout resilient design of 4H-SiC MOSFETs through staircase-like buffer layer

With the rapid development of SiC materials, high-power devices such as SiC MOSFETs have been widely used in aerospace, new energy, nuclear applications, and other fields. This places higher demands on their reliability, especially about radiation effects. This paper proposes a 4H-SiC staircase-like buffer layer MOSFET (SBL-MOSFET) with a hardened structure against single-event burnout (SEB). A comparison is made with conventional VD-MOSFET, gauss buffer layer MOSFET (GBL-MOSFET), and double buffer layer MOSFET (DBL-MOSFET) through TCAD simulations. The performance of the SBL-MOSFET against single-event burnout is studied by investigating the electric field distribution, impact ionization rate, hole concentration, and lattice temperature. The simulation results demonstrate that the staircase-like buffer layer structure effectively improves the distribution of high electric field, reduces the impact ionization rate, and thus increases the SEB threshold voltage compared to other structures. The proposed SBL-MOSFET exhibits a 67.5 % improvement in single-event burnout threshold voltage compared to the conventional VD-MOSFET, with slight degradation of breakdown voltage and leakage current. Meanwhile, there is no significant change in other electrical parameters.

Modeling of high uncertainty photovoltaic generation in quasi dynamic power flow on distribution systems: A case study in Java Island, Indonesia

Integrating uncertainties associated with photovoltaic (PV) generation is an important aspect used to ensure the planning and operation of power distribution systems. Therefore, this research proposed an uncertainty model for PV generation by combining the methods of change point detection, cyclic k-means clustering (KMC), Monte Carlo simulation (MCS) with freedman diaconis estimator (FDE), and KMC with soft-dynamic time warping (DTW). Firstly, a seasonal split was performed using change point detection techniques and cyclic KMC to identify shifts in global horizontal irradiance (GHI) points. Secondly, the uncertainty of the GHI was generated using MCS for each season and the FDE method to optimize the number of bins of the data distribution. Finally, the PV generation curve from MCS was simplified through KMC with the soft-DTW metric, which facilitated a more straightforward representation of a PV profile. The impact of PV profile integration on quasi-dynamic power flow was tested on an IEEE 33 Bus system. The voltage profile on the feeder significantly impacted the PV integration, specifically during hours when high PV power is produced. For instance, at 11:00 a.m., voltage values on buses 18, 17, and 33 increased from 0.933, 0.934, and 0.935, respectively, to 0.982, 0.980, and 0.972. Similarly, with the value of power losses, the greater the PV power profile produced at a certain hour, the smaller the losses generated. The experimental results of the uncertainties PV model proposed in this research indicated that changes in electrical parameters change over time according to the input PV power profile produced.