Peak Value Of Current Research Articles

Dummy imprinted electrochemical sensor for the selective detection of camostat mesylate.

Both molecularly imprinted polymer (MIP) and dummy-imprinted polymer (DIP) sensors were designed and comparatively analyzed for the determination of camostat mesylate (CAM). MIP and DIP sensors were designed with CAM, guanidine (GUA), and dimethylformamide (DMF) as target molecules and para-aminobenzoic acid (p-ABA) as a functional monomer using the electropolymerization (EP) method on the surface of screen-printed gold electrodes (SPAuE). The created sensors' morphological and electrochemical characteristics were examined to verify their construction. Additionally, the alterations on the electrode surface at the molecular and electronic levels were assessed using quantum chemistry calculations. The dynamic linear range of the MIP-based sensors designed under optimized experimental conditions was 2.5 × 10-13-2.5 × 10-12M, while it was 2.5 × 10-12-2.5 × 10-11M and 2.5 × 10-12-5.0 × 10-11M for the DIP-based sensors prepared using GUA and DMF, respectively. The impact of several interfering compounds on the CAM peak current was assessed to determine the selectivity. The RSD and recovery values were computed with 100 times more interfering agents present. The reproducibility of peak current RSD values of poly(Py-co-p-ABA)@CAM@MIP/SPAuE, poly(Py-co-p-ABA)@GUA@DIP/SPAuE, and poly(Py-co-p-ABA)@DMF@DIP/SPAuE sensors were 1.85%, 2.25%, and 2.33%, respectively. In addition, the recovery values ​​of MIP and DIP-based sensors in commercial serum samples were 99.36%, 99.47%, and 100.51%, respectively. The imprinting factor (IF) values were computed for the competitive compounds with comparable chemical structures. The developed sensor was also effectively used to measure CAM in commercial serum samples. In summary, the designed sensors demonstrated highsensitivity, selectivity, repeatability, and reproducibility against the CAM molecule.

Terahertz radiation affects the dynamics of neurons by decreasing membrane area ratio.

Terahertz radiation affects the dynamics of neurons by decreasing membrane area ratio.

Cost-effective, label-free electrochemical aptasensors for rapid detection of concanavalin A with screen printed electrodes.

Cost-effective, label-free electrochemical aptasensors for rapid detection of concanavalin A with screen printed electrodes.

Production of nitrogen oxides by spark discharges in air generated by a piezoelectric transformer

Discharges in air have found a number of medicinal applications, where they act, directly or indirectly, on biological objects. During the direct action, they are considered generators of antibacterial agents, such as NO, NO2, O3, and H2O2, which can selectively affect the cancerous cells or aid in wound healing. In the indirect action, the discharges produce plasma-treated water, which is further used to treat biological objects. The plasma activation of water consists in production of long-lived reactive nitrogen and oxygen species in the water, whose source are the particles that are produced by the discharges in the gas phase. In this work, a source of nonequilibrium low-temperature plasma based on a piezoelectric transformer was used. The nitrogen oxides were produced by spark discharges in air that were periodically generated between the transformer and an ungrounded metal surface. The generated discharges were ≈20-ns-long with an average peak current value of 0.34 A. The frequency of discharge generation was ≈88 kHz with a consecutive alternation of the voltage polarity. The qualitative and quantitative study of the nitrogen oxide production was performed using absorption infrared spectroscopy. During the discharge generation, NO, NO2, and N2O molecules were produced, along with the isomers of the nitrous acid HONO. The particle concentrations were calculated, and the time dynamics of their production was shown. The transition of the NO molecules into NO2 by oxidation of NO by molecular oxygen was shown. Estimates of the efficiency of the particle production were also calculated.

Determination of hordenine in beer samples and bodybuilding supplement at the electrified liquid-liquid interface.

Determination of hordenine in beer samples and bodybuilding supplement at the electrified liquid-liquid interface.

Digital Predictive Peak Current Control Strategy for the High-Order Superbuck Converter

This paper proposes a digital predictive peak current control (PPCC) strategy for superbuck converters. The proposed strategy incorporates a current predictor to calculate the output current and a peak current controller to calculate the required duty ratio for the next switching cycle. The duty ratio is precalculated ahead of a switching cycle, which creates a switching cycle for signal samplings and digital calculations. At the end of the next switching cycle, the output current peak value is regulated to match the reference value. The proposed strategy regulates the output current peak value to the reference value within two switching cycles. This increases the current loop bandwidth to π/T rad/s, which optimizes the transient performance. Moreover, a new damping parameter design method based on the damping ratio is given. Furthermore, a simplified version is proposed to facilitate digital realization. This version directly calculates the required duty ratio, which significantly reduces digital calculations. Finally, the experimental results demonstrate the effectiveness of the proposed control strategy in improving the transient performance of the superbuck converter.

Study on Trajectory Optimization of Robot by Heuristic and Learning

A trajectory, which determines the change of the displacement and posture of a robot with time, influences dynamic torque or energy during the operation. Although various methods for optimizing the trajectories have been proposed, most of them require the exact model that is difficult to construct. Previously, the authors proposed the method for optimizing the trajectories of an industrial robot without the dynamic model by using a heuristic algorithm. The proposed method can reduce the energy or peak current value consumed in the motor. However, the proposed method cannot be available for the operation where the required path of a robot often varies, because those cases need to explore the optimal trajectory with each path, and then a quite few numbers of driving the actual robot for exploring will be required. Therefore, this paper proposed a method for instantaneously optimizing the trajectories by using a neural network (NN) that is constructed by using the optimal trajectories obtained with the heuristic algorithm. In this paper, first, the optimal start position and the optimal operation times of an industrial robot is respectively explored by the heuristic algorithm using the average power consumed in the motor as the evaluation value. Next, a NN learned the parameters of the optimal trajectories explored by the heuristic algorithm for various paths. The constructs NN will generate optimal trajectories that reduce the evaluation values to the same extent as the trajectories explored by the heuristic algorithm. Namely, the proposed method using the NN can estimate the optimal trajectories in a shorter time than the method using the heuristic algorithm.

Optimization of Zinc and Aluminum Hydroxyquinolines for Applications as Semiconductors in Molecular Electronics.

This work explores the dispersed heterojunction of tris-(8-hydroxyquinoline) aluminum (AlQ3) and 8-hydroxyquinoline zinc (ZnQ2) with tetracyanoquinodimethane (TCNQ) and 2,6-diaminoanthraquinone (DAAq). Thin films of these organic semiconductors were deposited and analyzed, with their structures calculated with the B3PW91/6-31G** method. The optimized structure for AlQ3-TCNQ, AlQ3-DAAq, is achieved by means of three hydrogen bonds, whereas for ZnQ2-DAAq, two hydrogen interactions are predicted. These structures were recalculated including the GD3 dispersion term. A stable ordering was also achieved for AlQ3-TCNQ-GD3, AlQ3-DAAq-GD3, and ZnQ2-DAAq-GD3 with four and two hydrogen contacts for the former and the two latter, respectively. Infrared (IR) and UV-visible spectroscopy confirmed these theoretical predictions, in addition to obtaining the optical band gap for the films. The optical band gap values ranged between 1.62 and 2.97 eV (theoretical) and between 2.46 and 2.87 eV (experimental). Additional optical parameters and electrical behavior were obtained, which indicates the potential of the films to be used as organic semiconductors. All three films showed transmittance above 76%, which also broadens the range of applications in electrodes, transparent transistors, or photovoltaic cells. Devices fabricated using these materials displayed ohmic electrical behavior, with peak current values between 2 × 10-3 and 6 × 10-3 A.

Investigation of Structural, Optical, Electrical, and Biological Properties of a Porous Platinum Electrode for Neurostimulation Devices.

The structural and optical properties, as well as the electrical and biological characteristics of a porous platinum (Pt) structure for neurostimulation applications, are investigated. Critical factors such as biocompatibility, electrical performance, and structural and optical differences, which can adversely affect the functionality of implantable devices, are systematically analyzed and compared with general electrodes. By employing an integration of three-dimensional simulations and implantation experiments, we demonstrate that the remarkably extensive surface area, low reflectance, and outstanding peak current values inherent in porous Pt facilitate effective stimulation while simultaneously ensuring a high degree of biological safety. Our findings suggest that these beneficial characteristics collectively position porous Pt as a notably promising candidate for implantable electrodes in biomedical devices.

Electrodeposition of Ni-Co thin films from ammonia-chloride electrolyte

This study presents the research results on the co-deposition of nickel and cobalt from an alkaline electrolyte containing glycine. For this purpose, cyclic and linear polarization curves of co-deposition were obtained at various cobalt concentrations, different poten-tial sweep rates, and electrolyte temperatures. It was established that the co-deposition process occurs anomalously, with the cobalt content in the deposited films exceeding that of nickel. The deposits obtained under optimal conditions contained 37.25 % Ni and 51.43 % Co. The study of the effect of the potential sweep rate on the co-deposition process of nickel and cobalt revealed a linear relationship between the current peak value and the square root of the potential sweep rate. This indicates that the initial stage of Ni-Co co-deposition is controlled by the diffusion of the metal ions to the cathode surface. When recording polarization curves on a rotating disk electrode at different rotation speeds, the relationship between the current peak value and the square root of the electrode rotation speed was also linear at relatively low rotation speeds. However, at higher rotation speeds, the process was controlled by electrochemical polarization. The co-deposition of Ni with Co was confirmed through X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy analyses. The investigation of the catalytic activity of Ni-Co deposits in a neutral medium (0.5 M Na₂SO₄) demonstrated that the amorphous thin films, not subjected to annealing, exhibited the best electrocatalytic properties for the hydrogen evolution reaction. The Tafel slope was determined to be 118 mV dec-1.

Prediction of Transformer Residual Flux Based on J-A Hysteresis Theory

Circuit breakers are effectively utilized for the controlled switching technique to mitigate inrush current when energizing an unloaded transformer. The core of the controlled switching technique is to obtain the appropriate closing angle based on the residual flux after opening. For the prediction of residual flux, the voltage integration method faces the difficult problem of determining the integration upper limit, while the Jiles- Atherton (J-A) model has the advantages of clear physical meaning of parameters, accurate calculation, and the ability to iteratively solve residual magnetism. It has low dependence on the initial conditions and greatly avoids the influence of DC offset and noise on measurement results. Firstly, an improved particle-swarm optimization algorithm is proposed in this paper to address the problem of slow convergence speed and susceptibility to local optima in current particle-swarm optimization algorithms for extracting J-A model parameters. The problem of slow convergence speed and susceptibility to local optima in traditional particle-swarm optimization algorithms is solved by optimizing the velocity and position-update formulas of particles in this algorithm. This new algorithm not only accelerates convergence speed, but also balances the overall and local search capabilities. Then, based on the J-A model, residual flux prediction of the transformer is carried out, and a transformer no-load energization experimental platform is built. A simulation model combining the J-A model and classical transformer is constructed using PSCAD/EMTDC to predict the residual flux of the transformer at different closing angles. Finally, by combining simulation with actual experimental waveform data, the accuracy of residual flux prediction was verified by comparing the peak values of the inrush current.

Structural, Electrochemical, and Supercapacitor Characterization of Double Metal Oxides Doped Within ZIF-8 Composites

This study investigates the application of double metal oxide zinc ferrite (ZnFe2O3) doped within zeolitic imidazolate framework-8 (ZIF-8) composites for structural, electrochemical, and supercapacitor characterization. The structural characterization has been carried out using XRD, FTIR, DTA, UV-VIS, and HRTEM. By incorporating ZnFe2O3, significant enhancements in the structural integrity and morphology of the ZIF-8 matrices have been achieved, with a decrease in the average crystallite size by about 23%. At 500 °C, the DTA analysis indicated that the weight loss associated with ZnFe2O3 decreased by approximately 5%. The estimated Eg values are 3.08 eV and 3.28 eV for ZIF-8 and ZIF-8@ZnFe2O3, respectively. Regarding the electrochemical performance of the ZIF-8@ZnFe2O3, the anodic peak current density is approximately 0.0025 A (at around 0.5 V), at a scan rate of 10 mV/s. The peak current values increase more rapidly, by about 41%, with increasing scan rate when ZnFe2O3 is present, indicating a synergistic effect between the ZIF-8 and ZnFe2O3 components. The high observed current density peak at 0.03 V can be attributed to the Fe2+/Fe3+ redox couple, facilitated by the ZnFe2O3 component. The ZnFe2O3 addition enhances the electrochemical activity of ZIF-8, leading to increased peak current values at various scan rates. This suggests that the ZnFe2O3 may facilitate charge transfer or improve the conductivity of the material.

Simulation study on the characteristics of dielectric barrier discharge with the non-uniform coating layer

Abstract To further improve the efficiency of DBD applications, the design concept of non-uniform electrode-coated catalysts is proposed in this study. A two-dimensional fluid simulation model of plate dielectric barrier discharge is established to study the impact of the relative dielectric constant, thickness, and width of the non-uniform coating layer on the discharge characteristic. The discharge current, electric field strength, and electron density are analyzed respectively from positive and negative half cycles. The findings show that the coating layer's addition can promote the discharge current to some extent. When the relative dielectric constant of the coating layer increases, the peak value of positive and negative discharge current, the maximum electron density, and the maximum electric field strength in the positive half-cycle increase, while the negative half-cycle decreases. With the rise of the coating layer thickness, the peak discharge current, the maximum electric field strength, and the maximum electron density in positive and negative half-cycles decrease gradually. As the width of the coating layer increases, the maximum field strength and maximum electron density at the time of the negative half-cycle decrease, while the positive half-cycle increases.
The results provide a basis for further studying the effect of the non-uniform coating layer on dielectric barrier discharge.

ДОСЛІДЖЕННЯ ВМІСТУ СУКРАЛОЗИ У ГАЗОВАНИХ НАПОЯХ РІЗНИХ ВИРОБНИКІВ

OF DIFFERENT MANUFACTURES It was established that spectroscopic and chromatographic methods of analyzing were used to determine sucralose. Given that the spectroscopic method of analysis requires specific preparation of samples is insufficiently accurate and sensitive, and the chromatographic method is expensive, the electro-analytical method of determination was chosen for the research. This is justified by the structure of the molecule (it contains functional groups that can be oxidized electrochemically). Electrochemical experiments were carried out using a potentiostat-galvanostat on a three-electrode setup with a glassy carbon electrode as a working electrode, a platinum electrode as an auxiliary electrode and a silver chloride electrode for comparison. The study utilized non-carbonated beverages Continente (Portugal) and Xixo (Hungary), as well as carbonated beverages Sumol Zero (Portugal) and Fanta Shokata (Ukraine).The manufacturer indicated the presence of sucralose in all of them. Based on the conducted research and corresponding calculations, it was established that the beverages are safe for consumption. Natural processes of photo-, photoelectro-, and electrodegradation in soil and wastewater reduce the problems of sucralose accumulation in the environment. Therefore, to prevent diffusion to the anode space with the release of gaseous chlorine, membrane electrolysis is applied (the membrane is made of polyvinylpyridine), which separates the cathode and anode spaces and does not allow chloride ions to reach the anode. In this case, water electrolysis or electrooxidation of hydroxyl ions occurs at the anode with the formation of gaseous oxygen. Electroanalytical determination of sucralose was also conducted using the method of cyclic voltammetry. The fact that the electrochemical determination of sucralose took place can be judged by a gradual but sharp increase in the current value at certain potential values. In this case, the intensity of this increase depends on the concentration of the sweetener. A solution with a neutral pH level was used as the background electrolyte. Materials based on carbon (graphite, carbon nanotubes) were used as the working electrode. We proposed a new method for determining sucralose, associated with the dependence of the peak current value during its electrochemical oxidation on the concentration. At the same time, a linear relationship between the peak current value and the sweetener concentration is maintained.

Design Guidelines for Fractional Order Cascade Control in DC Motors: A Computational Analysis on Pairing Speed and Current Loop Orders Using Oustaloup’s Recursive Method

Nested, or cascade speed and torque control has been widely used for DC motors over recent decades. Simultaneously, fractional-order control schemes have emerged, offering additional degrees of control. However, adopting fractional-order controllers, particularly in cascade schemes, does not inherently guarantee better performance. Poorly paired fractional exponents for inner and outer PI controllers can worsen the DC motor’s behavior and controllability. Finding appropriate combinations of fractional exponents is therefore crucial to minimize experimental costs and achieve better dynamic response compared to integer-order cascade control. Additionally, mitigating adverse couplings between speed and current loops remains an underexplored area in fractional-order control design. This paper develops a computational model for fractional-order cascade control of DC motor speed (external) and current (internal) loops to derive appropriate combinations of internal and external fractional orders. Key metrics such as overshoot, rise time, and peak current values during speed and torque changes are analyzed, along with coupled variables like speed drop during torque steps and peak torque during speed steps. The proposed maps guide the selection of effective combinations, enabling readers to deduce robust or adaptive designs depending on specific performance needs. The methodology employs Oustaloup’s recursive approximation to model fractional-order elements, with MATLAB–SIMULINK simulations validating the proposed criteria.

AI-Based Discrimination of Faradaic Current against Nonfaradaic Current Inspired by Speech Denoising.

Cyclic voltammetry (CV) has been a powerful technique to provide impactful insights for electrochemical systems, including reaction mechanism, kinetics, diffusion coefficients, etc., in various fields of study, notably energy storage and energy conversion. However, the separation between the faradaic current component of CV and the nonfaradaic current contribution to extract useful information remains a major issue for researchers. Herein, we report a deep learning algorithm inspired by speech denoising that utilizes the theoretical faradaic current as a study target and predicts it from the overall current response from cyclic voltammograms. This deep neural network (DNN) is constructed from a series of fully connected layers, which apply a weight matrix to the inputs and transform it using an activation function to obtain the desired regression. Our model performed well with overall mean absolute percentage errors (MAPEs) of 6.36% between theoretical faradaic currents and the predicted responses from the total currents, with a peak position difference of 2.56 mV for anodic peaks and 2.44 mV for cathodic ones. Furthermore, the algorithm is also capable of extracting peak current values from experimental data with 3.37% MAPE and minimal peak position error (less than 0.75 mV). This innovative approach may be used as a tool to assist researchers in studying electrochemical systems using CV.

A novel electrochemical sensor for the determination of cadmium ions based on nitrogen-enriched carbon modified electrode

In the present work, nitrogen-doped carbon was synthesized starting from a chitosan/urea mixture and immobilized at the surface of a bare glassy carbon electrode to detect Cd(II) ions using differential pulse-anodic stripping voltammetry method (DP-ASV). The synthesized nitrogen-doped carbon showed a significant potential for determining Cd(II) ions. Doping carbon with nitrogen atoms gives a structure with increased valence band energy, leading to acceleration of the electron transfer by creating an interaction of nitrogen’s free electrons with Cd(II), which subsequently increases the peak current value. After the characterization of nitrogen-doped carbon by various methods, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to study the prepared sensor’s electrochemical behavior. Under optimal conditions, the proposed sensor has a linear response of 3.0 to 150 nM and its detection limit is 2.0 nM. This sensor can analyze Cd(II) in tap and river water as real samples.

ОЦЕНКА ЭФФЕКТИВНОСТИ ПРЕОБРАЗОВАТЕЛЬНЫХ СХЕМ ДЛЯ ЗАРЯДНЫХ СТАНЦИЙ ЭЛЕКТРОТРАНСПОРТА

Relevance With the rapid growth in popularity of electric vehicles and the increasing need for charging infrastructure, evaluating the effectiveness of circuit solutions for charging stations is becoming an increasingly important task. Currently, the development of chargers is required to reduce the charging time of an electric vehicle, increase the efficiency of converting mains voltage to direct current to charge the battery, with high reliability and affordable cost. Aim of research This article discusses various schemes for the implementation of charging stations, in particular, the use of a single-phase converter. The circuits are compared by the values of the transmission coefficients of the filter and harmonic distortion. The higher the value of the transmission coefficient, the more effective the filter is. In turn, a low harmonic distortion coefficient means a low peak current value, less heating of the elements and a low level of electromagnetic interference. Research methods The MatLab/Simulink computer simulation environment was used to determine the transmission coefficient of the filter, as well as the harmonic distortion coefficient. Results As a result of the research, it was found that the best characteristics for use in charging stations are provided by a scheme based on a step-up alternating PFC, with a harmonic distortion coefficient of 1.31 %, which is better than that of a scheme based on a step-up PFC converter with a harmonic distortion coefficient of 2.83 %.

Rapid voltammetric determination of hemagglutinin in saliva using magnetic nanoparticles modified with triazolotriazine in a portable cell design

Express determination of the viral nature of the diseases is one of the most important tasks of modern medicine. Portable electrochemicalanalytical devices are used to complement standard laboratory analytical methods and implement analysis at the patient's bedside. A rapid approach of voltammetric determination of the viral marker protein hemagglutinin (НA) in saliva using portable electrochemical microcell based on the three-electrode planar system (TPS) and magnetite nanoparticles modified with 3-nitro-4‑hydroxy-1,4-dihydro-7-propargylthio-1,2,4-triazolo[5,1-c][1,2,4]triazine (MNPs-Aza) was developed. MNPs-Aza were synthesized by carbodiimide cross-linking and characterized by infrared spectroscopy and square wave voltammetry. Modified MNPs were used simultaneously as carriers of the HA receptor and as agents for HA-Aza complexes concentrating on the surface of the working electrode. The normalized difference between the peak current values of the first stage of electroreduction of Aza before and after selective interaction with the HA in the analyzed sample (I*) was used as the analytical signal. Under the selected operating conditions of the developed portable microcell, linear calibration I* = (12.81±0.26) lg сHA + (136.75±1.73) was obtained in the range of 10–3–10–9 M. The limit of detection (LOD) calculated by the 3σ criteria was 8.4·10–10 M. The developed approach was successfully tested on model solutions and real saliva samples.

Laser ablation-induced convenient fabrication of surfactant-free platinum nanospheres with clean surface structures for enhanced electrocatalytic methanol oxidation

Laser ablation-induced convenient fabrication of surfactant-free platinum nanospheres with clean surface structures for enhanced electrocatalytic methanol oxidation