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Optimization of the spindle speed during milling of large-sized structures with the use of technique of Experiment-Aided Virtual Prototyping
PublikacjaIn the paper are presented considerations concerning vibration suppression problems during milling of large-sized workpieces with the use of innovative method of matching the spindle speed of cutting tool. It depends on repeatable change of the spindle speed value as soon as the optimal vibration state of the workpiece approaches. The values of dominant “peaks” in the frequency spectra and the Root Mean Square (RMS) values of time...
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A Conformal Circularly Polarized Series-Fed Microstrip Antenna Array Design
PublikacjaA conformal circularly polarized series-fed microstrip array design for broadside radiation is presented. The array aperture under design is conformal to a cylindrical surface of a given radius. The approach we present primarily addresses focusing of the circularly polarized major lobe of the conformal array by proper dimensioning of the aperture spacings. The proposed analytical models yield the values of the element spacings...
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Evolutionary Algorithm for Selecting Dynamic Signatures Partitioning Approach
PublikacjaIn the verification of identity, the aim is to increase effectiveness and reduce involvement of verified users. A good compromise between these issues is ensured by dynamic signature verification. The dynamic signature is represented by signals describing the position of the stylus in time. They can be used to determine the velocity or acceleration signal. Values of these signals can be analyzed, interpreted, selected, and compared....
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Bayesian Optimization for solving high-frequency passive component design problems
PublikacjaIn this paper, the performance of the Bayesian Optimization (BO) technique applied to various problems of microwave engineering is studied. Bayesian optimization is a novel, non-deterministic, global optimization scheme that uses machine learning to solve complex optimization problems. However, each new optimization scheme needs to be evaluated to find its best application niche, as there is no universal technique that suits all...
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Investigating the suitability of the matched fiber Bragg grating approach for guided wave based structural health monitoring
PublikacjaFiber Bragg grating (FBG) sensors are thought to be ideal sensors for structural health monitoring (SHM). Amplitude based techniques such as matched filters and the edge-filtering have been proposed to fulfill the high sampling rates necessary for guided waves (GW) sensing. The current research for the first time shows the inherent robustness the matched filter technique provides to the sensing system. The matched system is realized...
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Improvement of electrochemical action of zinc-rich paints by addition of nanoparticulate zinc
PublikacjaThe influence of nanosized particles on electrochemical action of standard zinc-rich paints by means of SEM as well as potential and impedance measurements has been investigated. The motivation for doing this was to obtain additional electrical connection between the spherical microparticles themselves and zinc particles and steel substrate. Overall zinc content was at the level of 92% by weight. Samples with different concentration...
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Electrical conductivity and relaxation processes in V2O5 nanorods prepared by sol–gel method
PublikacjaProperties of high purity V2O5 nanorods prepared by a sol – gel method are presented. The studied materials were characterized by: X-ray diffractometry (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The electrical impedance was measured as a function of temperature and frequency. The obtained results show that the electrical conductivity increases with increasing temperature. The d.c. conductivity...
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Left-handed propagation characteristics of a dielectric and metal-loaded periodic circular waveguide
PublikacjaIn this paper, a periodic dielectric/metallic rod is located in a circular waveguide to obtain left-handed operation. Two geometries of the dielectric/metallic rod are proposed and examined. The dispersion characteristics of the investigated waveguides are obtained using a surface impedance model. Moreover, equivalent circuit models are proposed allowing for calculation of the dispersion characteristics and scattering parameters...
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Determination of Mathematical Model Parameters of a Medium Frequency Transformer
PublikacjaThe paper presents the results of experimental studies of the medium frequency transformer. The object of the research was a prototype of a single-phase transformer with a core made of ferrite I-core elements and windings made of Litz conductors. The research was carried out to determine the parameters of the transformer's mathematical model. The scope of the tests included determining the magnetic hysteresis loop and measuring...
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A novel sensor for measuring temperature profile during the thermoablation
PublikacjaAbstract — A novel approach for monitoring a temperature distribution inside a tissue during thermoablation is presented in the paper. A thermal profile is measured using a set of serially connected thermistors each bypassed by a capacitor. This technique allows a two-wire and simultaneous multi- point measurements using a multi-frequency measurement of electrical impedance. It is...
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Insightful Analysis of Phenomena Arising at the Metal|Polymer Interphase of Au-Ti Based Non-Enzymatic Glucose Sensitive Electrodes Covered by Nafion
PublikacjaThis paper focuses on the examination of glucose oxidation processes at an electrode material composed of gold nanoparticles embedded in a titanium template. Three dierent conditions were investigated: the chloride content in the electrolyte, its ionic conductivity and the presence of a Nafion coating. The impact of the provided environment on the oxidation reaction was evaluated by cyclic voltammetry (CV) and electrochemical impedance...
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Exploring Mechanism of Corrosion Inhibition of WE43 and AZ31 Alloys by Aqueous Molybdate in Hank’s Solution by Multisine Impedimetric Monitoring
PublikacjaThe concept of utilizing multisine dynamic electrochemical impedance spectroscopy to monitor effectiveness of a model molybdate inhibitor for AZ31 and WE43 Mg alloys is proposed. The corrosion kinetics and instantaneous values of inhibition efficiency (IE) of molybdate at concentrations up to 150 mM were examined. The inhibitor provides inhibition in Hank’s solution at concentrations starting from ca. 25 mM, with the IE of about...
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Morphological and electrochemical characterization of ceramic carbon foam electrodes water treatment applications
Dane BadawczeThis dataset contains morphological and electrochemical characterization of ceramic carbon foam employed as an electrode (CFFE) for the oxidation of a target pollutant. The dataset includes:
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The electrical conductivity relaxation curve of the SrxTi0.30Fe0.70O3 (x=0.90 and 1.00) at 700 °C
Dane BadawczeIn this dataset are presented exemplary curves used for analysis of the electrical conductivity relaxation (ECR) mesurement of the SrxTi0.30Fe0.70O3 (x=0.90, 1.00) materials. The applied measuring temperature were 700 °C. Studies were performed in a small tube furnace (internal diameter ~20 mm) with 64 cm3 gas volume. During the four-point single frequency...
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Electronic conductivity in the SiO2-PbO-Fe2O3 glass containing magnetic nanostructures
PublikacjaThe linear impedance spectra of iron–silicate–lead glass samples were measured in the frequency range from 1 MHz to 1 MHz and in the temperature range from 153 K to 423 K. The structure was investigated by means of XRD and atomic force microscopy. Local electrical and magnetic properties of the samples were tested with the aid of electrostatic force microscopy (EFM) and magnetic force microscopy (MFM). The obtained results show...
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Development Of Dynamic Method For Evaluation Of Corrosion Rate On The Example Of Organic Corrosion İnhibitor
PublikacjaMeasurements of the corrosion rate belong to the most important aspects of materials science. In order to reduce material loss corrosion inhibitors are used. However selection of proper inhibitor should be based on evaluation of its mechanism and effective concentrations. Mechanism of inhibition usually has dynamic character so physicochemical parameters are changing in time. Most of actually used methods...
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Electrochemical and photoelectrochemical properties of the interface between titania nanotubes covered by conducting polymer in aqueous by conducting polymer in aqueous electrolytes – The effect of various geometry and electrolytes concentration
PublikacjaIn the present work we show the impact of nanotubes (NTs) geometry of titania utilized as a substrate in organic-inorganic systems acting as a p-n junction on efficient conversion of radiation energy into electrochemical energy. The electrolytic bath composition and electrolysis conditions were controlled in order to obtain TiO2NTs of various geometry as a result of electrochemical oxidation of titanium foil. The electrode material...
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Novel Coplanar-Strip-Based Excitation Technique for Design of Broadband Circularly Polarization Antennas with Wide 3-dB Axial Ratio Beamwidth
PublikacjaIn this paper, a novel excitation technique for design of a single-point-fed compact low-profile wide-slot antennas with broadband circular polarization (CP) and wide 3 dB axial ratio (AR) beamwidth is presented. Two inverted L-shape parasitic strips placed coplanar to the microstrip line of an asymmetric CPW, and a horizontal strip that protrudes from the vertical edge of the backside ground plane of the substrate are used for...
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Dynamiczne wyznaczanie parametrów elektrycznego obwodu szeregowego
PublikacjaPo załączeniu napięcia na skutek istnienia inercji prąd w obwodzie zaczyna narastać od wartości zerowej do znamionowej. W tym czasie narastają spadki napięć na rezystancjach (impedancjach obwodu) do chwili spełnienia prawa Kirchhoffa. Można utworzyć układ ze sprzężeniem zwrotnym (układ regulacji stałowartościowej bądź nadążnej), który poszukuje parametrów obwodu spełniających prawa Kirchhoffa – elementy nie muszą być liniowe. W...
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Results of EIS measuremnts and DRT analysis of SrTi0.30Fe0.70O3-d oxygen electrode at 800 °C and 1% oxygen partial pressure by using three R-CPE fiting elements
Dane BadawczeThis dataset contains electrochemical impedance spectroscopy and Distribution of Relaxation Times analysis results for symmetrical cell with porous SrTi0.30Fe0.70O3-d oxygen electrodes sintered at 800 °C. EIS spectra were measured at 800 °C and 1% of oxygen partial pressure. EIS and DRT spectra of simmulated three R-CPE elements from equivalent circuit,...
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Results of EIS measuremnts and DRT analysis of SrTi0.30Fe0.70O3-d oxygen electrode at 800 °C and 1% oxygen partial pressure by using two R-CPE fiting elements
Dane BadawczeThis dataset contains electrochemical impedance spectroscopy and Distribution of Relaxation Times analysis results for symmetrical cell with porous SrTi0.30Fe0.70O3-d oxygen electrodes sintered at 800 °C. EIS spectra were measured at 800 °C and 1% of oxygen partial pressure. EIS and DRT spectra of simmulated two R-CPE elements from equivalent circuit,...
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Hybrid piezoelectric motor based on electroactive lubrication principle
PublikacjaA novel conception of hybrid piezoelectric motor is presented in this paper. Proposed conception required synchronised work of quasi-static and resonant piezoelectric actuators that results in a rotary movement. The motor's working principle is explained and the main characteristics are described. Studied topology is compared to the existing piezoelectric motors with regards to its field of applications. The assembling process...
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A Goal-Oriented Error Estimator for Reduced Basis Method Modeling of Microwave Devices
PublikacjaThis letter proposes a novel a-posteriori error estimator suitable for the reduced order modeling of microwave circuits. Unlike the existing error estimators based on impedance function residuals, the new one exploits the residual error associated with the computation of the scattering matrix. The estimator can be effectively used in the Reduced Basis Method (RBM) to automatically generate reduced-order models. The results of numerical...
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Phase Separation and Electrical Properties of Manganese Borosilicate Glasses
PublikacjaThe structure and electrical properties of manganese borosilicate glasses of a composition of xMnO-(0.8-x)SiO2-(0.2)B2O3 (x=0.4, 0.5 and 0.6 in mol) were investigated by impedance spectroscopy, SEM, XRD and confocal microscopy methods. The influence of composition on the glass structure and electrical properties was discussed. A separation of two amorphous phases was observed and it was concluded that one phase is SiO2-rich and...
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Assessment of copper surface coverage with corrosion inhibitor using AFM-based local electrical measurements
PublikacjaThe paper presents a new method of assessment of metal surface coverage with corrosion inhibitor and thus of inhibitor protective performance. It is based on the atomic force microscopy measurement performed in a contact mode. Apart from topography images the proposed approach allows acquisition of local DC maps and local electrical impedance spectra via application of DC bias voltage or AC perturbation signal between the conductive...
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Heterogeneous distribution of surface electrochemical activity in polycrystalline highly boron-doped diamond electrodes under deep anodic polarization
PublikacjaThe surface homogeneity of boron-doped diamond electrodes is variable and depends on anodic polarization conditions. The differentiation factor is the gradual and localized change in surface termination. A series of measurements under different polarization conditions was performed in order to investigate the scale of this effect. Nanoscale impedance microscopy (NIM) revealed large variation of surface resistance in individual...
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Tailoring the electrochemical degradation of iron protected with polypyrrole films for biodegradable cardiovascular stents
PublikacjaThe degradation of polypyrrole (PPy) coated iron is studied in phosphate buffer saline solution at 37 °C by odd random phase multisine electrochemical impedance spectroscopy (ORP-EIS). PPy is electropolymerized with anti-inflammatory salicylates incorporated in the film, as a drug release system. The modelling of EIS over time provides the quantitative description of the corrosion behaviour of the material. Thus, the reliable...
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Conductivity and viscosity changes of imidazolium ionic liquids induced by H2O and CO2
PublikacjaSeveral solutions of ionic liquids based on 1-ethyl-3-methylimidazolium cation saturated and unsaturated with carbon dioxide were prepared and characterized by electrochemical impedance spectroscopy. The in fluence of ILs saturation on its electrical conductivity was determined. Additionally, the in fluence of the water presence and variations of temperature on electrical properties of ionic liquids were investigated. Changes of...
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Analysis of Corrugated Coaxial Line with the Use of Body of Revolution and Finite Element Method
PublikacjaA combination of the body-of-revolution and finite element methods is utilized to the analysis of coaxial lines with corrugated rod and wall. Both periodic and non-periodic structures can be investigated. As the structure is axially symmetrical the two dimensional scalar-vector finite element method can be used, which allows for the investigation of complex geometries and is computationally efficient. A generalized impedance matrix...
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Dual Active Bridge (DAB) DC-DC converter for multilevel propulsion converters for electrical multiple units (EMU)
PublikacjaSemiconductor power devices made from silicon carbide (SiC) reached a level of technology enabling their widespread use in power converters. Two different approaches to implementation of modern traction converters in electric multiple units (EMU) have been presented in recent years: (i) 3.3-kV SiC MOSFET-based three-level PWM inverter with regenerative braking and (ii) 6.5-kV IGBT-based four-quadrant power electronic traction transformer...
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Structure and the space vector modulation for a medium-voltage power-electronic-transformer based on two seven-level cascade H-bridge inverters
PublikacjaThis study presents the structure and the space vector pulse-width modulation (SVPWM) for power electronic transformer (PET) based on two seven-level cascade H-bridge (CHB) inverters. The DC links of CHB inverters are coupled with nine dual-active bridge (DAB) converters with medium-frequency transformers. The DC-link voltages are equalised with two methods – through the control of DAB voltages...
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Suppression of Supply Current Harmonics of 18-Pulse Diode Rectifier by Series Active Power Filter with LC Coupling
PublikacjaThe reported research aims at improving the quality of three-phase rectifier supply currents. An effective method consists of adding properly formed booster voltages to the fundamental supply voltages using a series active filter. In the proposed solution, the booster voltages are generated by three single-phase systems consisting of inverters, LC filters, and single-phase transformers. The application of LC couplings ensures low...
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Single-Phase 15-Level Switched-Capacitor Boost Multilevel Inverter Topology for Renewable Energy Applications
PublikacjaGalvanic isolation is a vital part of a grid-connected solar PV system. With the growth of multilevel inverters for grid-connected applications, the multilevel inverters having isolation are not sufficiently discussed in the literature. In this paper, a 15-level isolated multilevel inverter topology requiring only thirteen switches is proposed. The envisaged configuration includes two cells, designated as upper and lower cells....
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Leakage Current Measurements of Surge Arresters
PublikacjaThe paper presents the methods of assessing the technical condition of varistor surge arresters used in laboratory tests and in operation—performed without disconnecting the arresters from the network. The analysis of the diagnostic methods was supplemented with the results of the measurements of the leakage current of arresters coming directly from their production and used in the power industry. Among the available methods of...
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Frequency-dependent coupling model for microwave band-pass filter
PublikacjaThe goal of this work was to create a circuit model which represents frequency-dependent coupling between microwave resonators. Our models are designed for in-line filters. The frequency-dependent coupling enables one to realize a transmission zero which is not possible in classical approach with frequency independent inverters. In addition, the proposed model allows us to observe out-of-band behavior, e.g. spurious resonance....
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Semantic Integration of Heterogeneous Recognition Systems
PublikacjaComputer perception of real-life situations is performed using a variety of recognition techniques, including video-based computer vision, biometric systems, RFID devices and others. The proliferation of recognition modules enables development of complex systems by integration of existing components, analogously to the Service Oriented Architecture technology. In the paper, we propose a method that enables integration of information...
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Measurements of transmission properties of Acoustic Communication Channels
PublikacjaTough transmission properties of shallow water acoustic channels (SWAC) highly limit the use of underwater acoustic communication (UAC) systems. An adaptive matching of modulation and signaling schemes to instantaneous channel conditions is needed for reliabledata communications. This creates, however, unique challenges for designers when compared to radio transmission systems. When communication system elements are in move, the...
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Solving Boundary Value Problems for Second Order Singularly Perturbed Delay Differential Equations by ε-Approximate Fixed-Point Method
PublikacjaIn this paper, the boundary value problem for second order singularly perturbed delay differential equation is reduced to a fixed-point problem v = Av with a properly chosen (generally nonlinear) operator A. The unknown fixed-point v is approximated by cubic spline vh defined by its values vi = vh(ti) at grid points ti, i = 0, 1, ... ,N. The necessary for construction the cubic spline and missing the first derivatives at the boundary...
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Dynamic Data Management Among Multiple Databases for Optimization of Parallel Computations in Heterogeneous HPC Systems
PublikacjaRapid development of diverse computer architectures and hardware accelerators caused that designing parallel systems faces new problems resulting from their heterogeneity. Our implementation of a parallel system called KernelHive allows to efficiently run applications in a heterogeneous environment consisting of multiple collections of nodes with different types of computing devices. The execution engine of the system is open for...
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Simulation-Based Design of Microstrip Linear Antenna Arrays Using Fast Radiation Response Surrogates
PublikacjaFast yet accurate technique for simulation-based design of linear arrays of microstrip patch antennas is presented. Our technique includes: (i) optimization of the corrected array factor of the antenna array under design for a phase excitation taper resulting in reduced side lobes; (ii) simulation-driven optimization of the array element for element dimensions resulting in matching at and about operational frequency, and (iii)...
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Objective relaxation algorithm for reliable simulation-driven size reduction of antenna structure
PublikacjaThis letter investigates reliable size reduction of antennas through electromagnetic-driven optimization. It is demonstrated that conventional formulation of the design task by direct footprint miniaturization with imposing constraints on electrical performance parameters may not lead to optimum results. The reason is that—in a typical antenna structure—only a few geometry parameters explicitly determine the antenna footprint,...
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Survey of Methodologies, Approaches, and Challenges in Parallel Programming Using High-Performance Computing Systems
PublikacjaThis paper provides a review of contemporary methodologies and APIs for parallel programming, with representative technologies selected in terms of target system type (shared memory, distributed, and hybrid), communication patterns (one-sided and two-sided), and programming abstraction level. We analyze representatives in terms of many aspects including programming model, languages, supported platforms, license, optimization goals,...
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Signal Reconstruction from Sparse Measurements Using Compressive Sensing Technique
PublikacjaThe paper presents the possibility of applying a new class ofmathematical methods, known as Compressive Sensing (CS) for recovering thesignal from a small set of measured samples. CS allows the faithful recon-struction of the original signal back from fewer random measurements bymaking use of some non-linear reconstruction techniques. Since of all thesefeatures, CSfinds its applications especially in the areas where, sensing is...
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Ln2(SeO3)2(SO4)(H2O)2 (Ln=Sm, Dy, Yb): A Mixed‐Ligand Pathway to New Lanthanide(III) Multifunctional Materials Featuring Nonlinear Optical and Magnetic Anisotropy Properties
PublikacjaBottom-up assembly of optically nonlinear and magnetically anisotropic lanthanide materials involving precisely placed spin carriers and optimized metal-ligand coordination offers a potential route to developing electronic architectures for coherent radiation generation and spin-based technologies, but the chemical design historically has been extremely hard to achieve. To address this, we developed a worthwhile avenue for creating...
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Jean Monnet Chair Workshop on Income and Wealth Inequalities
WydarzeniaOtwarte i bezpłatne warsztaty naukowe organizowane w ramach Jean Monnet Chair. Spotkanie w języku angielskim. Obowiązują wcześniejsze zapisy: jwo@zie.pg.gda.pl do 21.06.2018 r.
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Chemical diffusion coefficient of oxygen (D*) of the SrxTi0.30Fe0.70O3 (x=0.90, 0.95 and 1.00) at different temperatures
Dane BadawczeIn this dataset are presented D* values designated based on the electrical conductivity relaxation (ECR) mesurement of the SrxTi0.30Fe0.70O3 (x=0.90, 0.95, 1.00) materials. The applied temperatures were 800 °C, 750 °C, 700 °C, 650 °C, and 600 °C. Studies were performed in a small tube furnace (internal diameter ~20 mm) with 64 cm3 gas volume. During...
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Chemical oxygen surface exchange coefficient (k*) of the SrxTi0.30Fe0.70O3 (x=0.90, 0.95 and 1.00) at different temperatures
Dane BadawczeIn this dataset are presented k* values designated based on the analysis of the electrical conductivity relaxation (ECR) mesurement of the SrxTi0.30Fe0.70O3 (x=0.90, 0.95, 1.00) materials. The applied temperatures were 800 °C, 750 °C, 700 °C, 650 °C, and 600 °C. Studies were performed in a small tube furnace (internal diameter ~20 mm) with 64 cm3 gas...
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Performance of Haemophilus influenzae impedimetric biosensors based on screen-printed carbon electrodes (SPCE) with boron-doped diamond foils
Dane BadawczeThis dataset contains electrochemical impedance spectroscopy studies of SPCE electrodes containing boron-doped diamond BDD foils and functionalized towards detection of Protein D and Haemophilus influenzae.
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Doubly miniaturized rat-race hybrid coupler
PublikacjaTwo complementary miniaturization techniques have beenapplied to reduce the size of a rat-race hybrid coupler: (i) conventional microstrip sections have been replaced with their diminished lowimpedance counterparts as the first step of size reduction and (ii) novel fractal-shaped compact microstrip resonant cells dedicated to efficiently shorten low-impedance transmission line segments have been implemented as the second step of...
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Microstructure and Dielectric Properties of Barium-vanadate Glasses
PublikacjaThe ac and dc conductivity in barium-vanadate glasses was investigated as a function of temperature and frequency with the use of impedance spectroscopy. The topography and microstructure of glasses were investigated by the means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods. The XRD results show that all samples are amorphous but microscopy investigation reveals that glasses with greater amount of V2O5...