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Search results for: POLYNOMIAL IMPEDANCE ANALYSIS
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Implementation and Validation of Multisinusoidal, Fast Impedance Measurements in Atomic Force Microscope Contact Mode.
PublicationThis study presents a novel approach to impedance measurements. The methodology discussed is limited to contact in the sample-probe system under ambient conditions without the presence of electrolyte. Comparison with results of direct and alternating current measurements for well-defined metallic surfaces are made. In spite of idealization related to the type of contact examined, the proposed technique provides an improvement of...
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Selected aspects of modern X-ray structural analysis 2024
e-Learning CoursesSelected Aspects of Modern X-ray Structural Analysis
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Selected Aspects of Modern X-ray Structural Analysis 2023
e-Learning CoursesSelected Aspects of Modern X-ray Structural Analysis
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EM-Driven Multi-Objective Design of Impedance Transformers By Pareto Ranking Bisection Algorithm
PublicationIn the paper, the problem of fast multi-objective optimization of compact impedance matching transformers is addressed by utilizing a novel Pareto ranking bisection algorithm. It approximates the Pareto front by dividing line segments connecting the designs found in the previous iterations, and refining the obtained candidate solutions by means of poll-type search involving Pareto ranking. The final Pareto set is obtained using...
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Linearization in impedance measurements
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Application of galvanodynamic impedance spectroscopy for studying passive film cracking under mechanical strain
PublicationThe paper reports the results of simultaneous mechanical and electrochemical investigations on austenitic (18/8) stainless steel in a 2 % solution of sulphuric acid. The measurements were performed using Galvanodynamic Electrochemical Impedance Spectroscopy (GDEIS). Electrochemical analysis of mechanical passive layer cracking and repassivation conditions during a tensile test was carried out. Application of this methodology allowed...
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Dynamic Electrochemical Impedance Spectroscopy (DEIS) as a Tool for Analyzing Surface Oxidation Processes on Boron-Doped Diamond Electrodes
PublicationSurface oxidation processes play a key role in understanding electrochemical properties of boron-doped diamond (BDD) electrodes. The type of surface termination groups, which create the potential window of electrolytic water stability or hydrophobicity, influences such properties. In this study the kinetics of oxidation process under anodic polarization were studied in situ by means of Dynamic Electrochemical Impedance Spectroscopy...
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ESAIM: Mathematical Modelling and Numerical Analysis
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Impedance monitoring of corrosion degradation of plasma electrolytic oxidation coatings (PEO) on magnesium alloy
PublicationImpedance technique based on continuous multisinusoidal current perturbation was used to explain degradation process of plasma electrolytic oxidation coatings (PEO) on magnesium alloy. An obtained impedance spectrum was fitted by electrical equivalent circuit to describe properties of conversion layer on magnesium alloy. Additionally, galvanostatic mode maintained during experiment, with DC current equal to zero, allowed to achieve...
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Remote Monitoring System for Impedance Spectroscopy using Wireless Sensor Network
PublicationThe architecture of a miniaturized impedanceanalyser with wireless communication module for remoteImpedance Spectroscopy (IS) of anticorrosion coatings ondifficult-to-reach objects (e.g. on the steel construction ofthe bridge) is described in this paper. Some practical aspectsof implementation of a Wireless Sensor Network (WSN) arealso discussed. A low scale, middle range, WSN networkcomposed of a Base Station (BS) with a Personal...
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Design of a complex multiplier based on the convolution with the use of the polynomial residue number system
Publicationzaproponowano realizację mnożnika zespolonego opartego na algorytmie dekompozycyjnym skavantzosa i stouraitisa. mnożenie zespolone jest wykonywane jako splot 8-punktowy. przedstawiono przykład obliczeniowy i architekturę mnożnika dla małych liczb.
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Approaches to experiment based friction modeling: polynomial approximation versus ann approximation
PublicationBadano warunki (poziom wymuszeń), przy których następowało wzbudzenie drgań mechanicznych przy tarciu ślizgowym konforemnego skojarzenia próbek wykonanych z Al2O3 (płaskie czoło tulei obracającej się względem swojej osi - powierzchnia płaska). Uzyskane dane eksperymentalne wykorzystano następnie do zbudowania modeli - stosując aproksymację wielomianami albo sztuczną siecią neuronową (ANN).
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Generalized adaptive notch filters with frequency debiasing for tracking of polynomial phase systems
PublicationGeneralized adaptive notch filters are used for identification/tracking of quasi-periodically varying dynamic systems and can be considered an extension, to the system case, of classical adaptive notch filters. For general patterns of frequency variation the generalized adaptive notch filtering algorithms yield biased frequency estimates. We show that when system frequencies change slowly in a smooth way, the estimation bias can...
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Fundamentals of microscopic analysis
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Application of quartz crystal microbalance and dynamic impedance spectroscopy to the study of copper corrosion inhibitors
PublicationThe study investigates the application of Dynamic Electrochemical Impedance Spectroscopy (DEIS) and Electrochemical Quartz Crystal Microbalance (EQCM) techniques to examine the corrosion inhibition of copper by Benzotriazole and Sodium Folate in a 0.1 M NaCl solution. DEIS, an advanced version of Electrochemical Impedance Spectroscopy (EIS), allows for real-time monitoring of non-stationary electrochemical systems,...
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Evaluation of applicability of classic methods of a fault loop impedance measurement to circuits with residual current devices
PublicationMeasurement of fault loop impedance in low voltage grids and systems is in most cases performed to verify the effectiveness of protection against electric shock by automatic disconnection of supply. For the sake of measurement accuracy, it is advisable to perform it using large current. Unfortunately, in circuits with residual current devices which are very widely used nowadays, a large measurement current may trigger those devices...
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New Method of Non-Linear Electrochemical Impedance Spectroscopy with an Amplitude-Modulated Perturbation Signal
PublicationThe paper presents a new method of non-linear electrochemical impedance spectroscopy (NLEIS), which allows fast and nondestructive evaluation of the corrosion rate and determination of the Tafel coefficients values for a corrosion system under investigation. This method employs amplitude modulation of the ac perturbation signal. The study demonstrated that it was possible to obtain impedance characteristic as a function of the...
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Monitoring of breast tissue thermo-ablation by means of impedance measurements
PublicationW pracy przedstawiono rozważania dotyczące monitorowania jakości termoablacji zmian nowotworowych w piersi przy pomocy pomiarów impedancyjnych. Pokazano prototypowe konstrukcje sond do termoablacji jak również zaprezentowano wyniki symulacji i pierwszych eksperymentów. A usefulness of a developed probe combining power delivery to ablated breast tumour and simultaneous impedance measurements is discussed in the paper. It consists...
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Electrical and mechanical characterization of two-phase alloys by means of scanning probe microscopy in dynamic impedance spectroscopy mode
PublicationDynamic impedance spectroscopy, evaluated for measuring non-stationary systems, was used in combination with scanning probe microscope. Using this approach, localized impedance measurements in the AFM contact mode could be carried out. Additionally, impedance–force curves were made at each phase of investigated materials to illustrate the relation between impedance and the force applied to a probe. Therefore, correlation of electrical...
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Determination of time delay between ventricles contraction using impedance measurements
PublicationThe paper presents a novel approach to assessment of ventricular dyssynchrony basing on multichannel electrical impedance measurements. Using a proper placement of electrodes, the sensitivity approach allows estimating time difference between chambers contraction from over determined nonlinear system of equations. The theoretical considerations which include Finite Element Method simulations were verified using measurements on...
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Galvanostatic impedance measurements for the efficient adsorption isotherm construction in corrosion inhibitor studies
PublicationWe present an approach towards an accurate and time-efficient adsorption isotherm determination to evaluate the corrosion inhibitor interaction in electrolytic environments. The approach is based on dynamic impedance spectroscopy measurements in galvanostatic mode (g-DEIS). The studied corrosion inhibitor is continuously injected between the secondary cell and the corrosion cell. The efficiency corresponding to instantaneous inhibitor...
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Rapid multi-objective design optimization of miniaturized impedance transformer by Pareto front exploration
PublicationFast multi-objective optimization of compact impedance transformer is discussed. A set of alternative designs representing possible trade-offs between conflicting design criteria, i.e., electrical performance (here, wideband matching) and the structure size, is obtained through Pareto front exploration by means of surrogate-assisted methods.
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Ellipse-fitting algorithm implementation in the impedance measurement system based on DAQ card with FPGA
PublicationThe paper presents an implementation of the ellipse-fitting algorithm in the impedance measurement system based on DAQ card equipped with FPGA chip. The method implementation was tested by simulation means as well as experimentally in the designed and presented measurement system. Finally, the limit values of sampling parameters which assures satisfying accuracy were given.
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Response features for fast EM-driven design of miniaturized impedance matching transformers
PublicationA framework for low-cost EM-driven design optimization of compact impedance matching transformers is presented. Our technique is based on a bottom-up design where design requirements for the transformer circuit are translated into specifications for its building blocks. These elementary cells are optimized using response features. Subsequently, the entire circuit is fine-tuned using local response surface approximation models and...
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Multifrequency Nanoscale Impedance Microscopy (m-NIM): A novel approach towards detection of selective and subtle modifications on the surface of polycrystalline boron-doped diamond electrodes
PublicationIn this paper, we describe the modification of Nanoscale Impedance Microscopy (NIM), namely, a combination of contact-mode atomic force microscopy with local impedance measurements. The postulated approach is based on the application of multifrequency voltage perturbation instead of standard frequency-by-frequency analysis, which among others offers more time-efficient and accurate determination of the resultant impedance spectra...
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Analysis
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Cost-efficient simulation-driven design of compact impedance matching transformers
PublicationIn this paper, an algorithmic framework for cost-efficient design optimization of miniaturized impedance matching transformers has been presented. Our approach exploits a bottom-up design that involves translating the overall design specifications for the circuit at hand to its elementary building blocks (here, compact microstrip resonant cells, CMRCs), as well as fast surrogate-assisted optimization of the cells followed by simulation-based...
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In-situ odd random phase electrochemical impedance spectroscopy study on the electropolymerization of pyrrole on iron in the presence of sodium salicylate – The influence of the monomer concentration
PublicationIn this work, the potentiostatic electropolymerization of polypyrrole (PPy) on iron in aqueous solution of sodium salicylate and pyrrole is studied in situ by odd random phase electrochemical impedance spectroscopy (ORP-EIS). The influence of the pyrrole concentration on the electrosynthesis process is investigated. The ORP-EIS technique ensures a reliable analysis of the PPy electrosynthesis on iron by means of an advanced data...
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The Mott-Schottky characteristics of microwave pulsed-plasma polymerized allylamine by DEIS analysis
Open Research DataThe dataset contains the results obtained for the Mott-Schottky analysis of the microwave pulsed-plasma polymerized allylamine using the multifrequency perturbation signal with Dynamic Electrochemical Impedance Spectroscopy (DEIS) technique. The results were obtained using the perturbation composed of the elementary signals with a frequency range between...
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Efficient Gradient-Based Algorithm with Numerical Derivatives for Expedited Optimization of Multi-Parameter Miniaturized Impedance Matching Transformers
PublicationFull-wave electromagnetic (EM) simulation tools have become ubiquitous in the design of microwave components. In some cases, e.g., miniaturized microstrip components, EM analysis is mandatory due to considera¬ble cross-coupling effects that cannot be accounted for otherwise (e.g., by means of equivalent circuits). These effects are particularly pronounced in the structures in¬volving slow-wave compact cells and their numerical...
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Correction methods in impedance spectroscopy
PublicationW pracy przedstawiono trzy grupy metod, ktÓre mogą być zastosowane do korekcji danych pomiarowych uzyskanych za pomoca spektroskopii impedancyjnej.
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Design of a modular impedance tomography
PublicationW pracy przedstawiono konstrukcję, zasadę działania oraz podstawowe parametry tomografu impedancyjnedo przeznaczonego do pomiarów w gruncie.
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Local impedance spectroscopy of membranes
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Local impedance spectroscopy of membranes
PublicationCelem niniejszej publikacji jest zaprezentowanie zastosowania techniki Lokalnej Elektrochemicznej Spektroskopii Impedancyjnej (LEIS) do uzyskania lokalnej charakterystyki membran. Membranę wykonaną z polichlorku winylu (PCV), plastyfikowaną sebacynianem bis(2etyloheksylu) i domieszkowaną boranem tetradodecyloamoniowym zbadano pod kątem równomiernego rozkładu przewodnictwa na powierzchni badanej próbki. Lokalne pomiary impedancyjne,...
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Impedance of metastable pitting corrosion
PublicationPrzeprowadzono badania impedancyjne metastabilnego procesu korozji wżerowej. Kształt chwilowych widm impedancyjnych otrzymanych w wyniku eksperymentu jest ściśle związany z przebiegiem prądu dc. O szybkość korozji wewnątrz aktywnego zaatakowania decyduje proces przeniesienia ładunku. Ekspansja aktywnej powierzchni jest proporcjonalna do zmian podwójnej warstwy elektrycznej. Zaobserwowane zostały również zmiany rezystancji elektrolitu...
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Measuring the impedance of ultrasonic transducers.
PublicationW przypadku przetworników ultradźwiękowych charakteryzujących się zazwyczaj bardzo zmienną w funkcji częstotliwości impedancją jej pomiar stwarza szereg trudności. Nie nadają się do tego celu tanie, łatwo dostępne, przyrządy. Znane są drogie systemy badawcze stosowane do tego celu. Zazwyczaj przystosowane są one do takich pomiarów w szerokim paśmie częstotliwości, od pasma akustycznego aż do zakresu mikrofalowego. Natomiast,...
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Linear and nonlinear impedance in iron oxide glasses containing alkaline ions and alkali free
PublicationThe linear and nonlinear impedance spectra of oxide glasses were measured in the frequency range of 1 mHz to 1 MHz and in the temperature range of 153K to 483K. Two groups of iron oxide glass samples were prepared, the first one containing alkaline ions and the second one without alkali. In the first group, compositions of glasses were as follows: (in %mol) 50% SiO2 , 25% PbO, 15% Fe2O3 and 15% one of alkaline oxides: Na2O, K2O,...
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A method of earth fault loop impedance measurement without unwanted tripping of RCDs
PublicationIn low-voltage networks, earth fault loop impedance (EFLI) measurement is the basis for assessing the effectiveness of automatic disconnection of supply. Such a measurement is performed during initial and periodical verification, especially in a TN low-voltage network. Nowadays, due to widespread application of residual current devices (RCDs), such test is difficult in many circuits because RCDs operate during the test. In this...
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PHYTOCHEMICAL ANALYSIS
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The impedance of hydrogen oxidation reaction in a proton exchange membrane fuel cell in the presence of carbon monoxide in hydrogen stream
PublicationEvaluation of performance of a proton exchange membrane fuel cell, which is affected by carbon monoxide that pollutes the hydrogen stream, was presented. This influence was studied for carbon monoxide concentration of 125–325 ppb, which are close to values specified in ISO 14687:2019 standard. Performed studies provided crucial information for further development of fuel cell as an energy source for automotive application. Impedance...
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Ireneusz Kreja dr hab. inż.
PeopleGraduated from the mathematical class at the Nicolaus Copernicus High School in Gdańsk (1974). Master of Sciences in Civil Engineering after studies at Gdansk University of Technology (GUT), Poland (1974-1979). Since 1979 became an employee of the GUT. In 1989 earned a Ph.D. degree in Civil Engineering (with grade "Summa cum Laude") from the GUT. In 2008 obtained a D. Sc. (Habilitation) degree in Civil Engineering (with grade...
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Analiza decyzyjna/Decision analysis
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Market Analysis 2022/23
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Financial Analysis (lectures, 2022)
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Financial Analysis (22/23)
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Financial Analysis (summer 2024)
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Market Analysis 2023/24
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Study on surface termination of boron-doped diamond electrodes under anodic polarization in H2SO4 by means of dynamic impedance technique
PublicationAnodic oxidation is a popular way to modify termination bonds at boron doped diamond electrodes altering their electrochemical and physicochemical properties. Our studies, performed with dynamic electrochemical impedance spectroscopy technique, supported with X-ray photoelectron spectroscopy and ellipsometry analysis prove its utility in continuous on-line monitoring of impedance changes on the electrode surface under polarization...
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Solid State Conductivity of Optimized Polypyrrole Coatings on Iron Obtained from Aqueous Sodium Salicylate Solution Determined by Impedance Spectroscopy
PublicationIn this work the optimization procedure for corrosion resistance, surface analysis and electrical properties of PPy-Fe electrodes have been examined. Polypyrrole (PPy) film was electrochemically synthesized in a one step process from an aqueous solution of sodium salicylate and pyrrole with certain concentrations, different parameters and type of polymerization...
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Nonlinear and linear impedance of bismuth vanadate ceramics and its relation to structural properties
PublicationThe nonlinear and linear electrical properties, topography, and microstructure of bismuth-vanadate ceramics, were studied. The structurewas observed with the use of X-ray diffraction (XRD), scanning electronmicroscopy (SEM), atomic force microscopy (AFM) and confocal microscopy methods. The obtained results showed that ceramic is porous. Two phase transitionswere determinedwith the use of DSC measurements. The linear and nonlinear ac...