Filtry
wszystkich: 1403
wybranych: 1147
-
Katalog
Filtry wybranego katalogu
wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: LATTICES IMPEDANCE
-
Electromagnetic plane wave scattering from a cylindrical object with an arbitrary cross section using a hybrid technique
PublikacjaA hybrid technique combining finite-element and mode-matching methods for the analysis of scattering problems in open and closed areas is presented. The main idea of the analysis is based on the utilization of the finite-element method to calculate the post impedance matrix and combine it with external excitation. The discrete analysis, which is the most time- and memory-consuming, is limited here only to the close proximity of...
-
New Methods of Short-Circuit Current Limiting and Switching-off
PublikacjaPrzedstawiono wyniki badań symulacyjnych i eksperymentalnych hybrydowych indukcyjno-tyrystorowych ograniczników i wyłączników prądu zwarciowego. Impedancja dławika ogranicznika prądu jest wtrącana do obwodu zwarciowego dopiero w chwili, gdy prąd zwarciowy przekroczy wartość prądu wymuszonego w dławiku przez zewnętrzne źródło prądu. Ograniczanie dynamiki prądu zwarciowego jest bezzwłoczne. Układ nie generuje przepięć łączeniowych....
-
Termowizja jako narzędzie weryfikacji stanu elementów ochronnych SMD podczas badań udarowych
PublikacjaPrzedstawiono wyniki badań przyrostów temperatury rejestrowanych za pomocą kamery termowizyjnej ochronnych elementów SMD podczas wykonywania badań odporności na udary napięciowe wykonywane wg normy EN61000-4-5 dla różnych poziomów sprzężeń impedancyjnych
-
Zur Entwicklung der Steifigkeitsmatrizen fur dunnwandige Stabe
PublikacjaOn the development of stiffness matrices for thin-walled members
-
Metody i mikrosystemy pomiarowe impedancji do diagnostyki grubowarstwowychpowłok antykorozyjnych.**2003, 104 s. 90 rys. 18 tab. bibliogr. 106 poz. Rozprawa doktorska (04.03.2003 r.), Wydz. ETI. Promotor: prof. dr inż. R. Zielonko.
PublikacjaPraca jest rozprawą doktorską, której celem było opracowanie nowych metodpomiarowych i procedur diagnostycznych powłok antykorozyjnych, zwłaszczagrubowarstwowych, drogą identyfikacji parametrów impedancyjnych ich modeli(układów zastępczych), nadających się do realizacji praktycznej w mikrosys-temach pomiarowych przeznaczonych do pracy w terenie oraz realizacja przyk-ładowego mikrosystemu pomiarowo-diagnostycznego powłok...
-
Excitation of Circularly Polarized Wave via Single-Feed Metasurface-Integrated Compact Antenna for Internet of Things
PublikacjaA compact circularly polarized (CP) quasi-omnidirectional antenna is introduced for internet of things (IoT). The structure consists of two components implemented on FR-4 substrates, and sep-arated by an air gap: one printed with a rectangular patch fed through a matching network, and another with a metasurface and a ground plane. Two different methods for impedance matching are employed. An equivalent circuit model of the antenna...
-
The Impact of Crushed Rock Spoil on Pitting Corrosion of Selected Stainless Steel
PublikacjaThe paper presents the results of the pitting resistance investigations of selected stainless steels in the chloride environment and the simultaneous impact of erosive factors using the cyclic polarization technique. Additionally, using electrochemical techniques, ie: electrochemical impedance spectroscopy (EIS) and measurement of corrosion potential, the behavior of the passive layer of selected stainless steels in the environment...
-
A Wearable System Developed to Monitor People Suffering from Vasovagal Syncope
PublikacjaA wearable system for monitoring non-invasively signals invaluable when examining person suffering from vasovagal syncope is presented in the paper. Following signals are continuously recorded: electrocardiogram, photopletysmogram, impedance cardiogram and electrodermal resistance.
-
Antibacterial Porous Systems Based on Polylactide Loaded with Amikacin
PublikacjaThree porous matrices based on poly(lactic acid) are proposed herein for the controlled release of amikacin. The materials were fabricated by the method of spraying a surface liquid. Description is given as to the possibility of employing a modifier, such as a silica nanocarrier, for prolonging the release of amikacin, in addition to using chitosan to improve the properties of the materials, e.g., stability and sorption capacity....
-
Methodology of Selecting the Optimal Receptor to Create an Electrochemical Immunosensor for Equine Arteritis Virus Protein Detection
PublikacjaThe study reports a methodology of selecting the optimal receptor to create an electrochemical immunosensor for equine arteritis virus (EAV) protein detection. The detection was based on antigen recognition by antibodies immobilized on gold electrodes. Modification steps were controlled by electrochemical impedance spectroscopy and cyclic voltammetry measurements. In order to obtain the impedance immunosensor with the best parameters,...
-
Design and optimization of a novel compact broadband linearly/circularly polarized wide-slot antenna for WLAN and Wi-MAX applications
PublikacjaA novel topologically modified structure of a compact low profile wide-slot antenna for broadband applications is presented. The antenna comprises a modified E-shaped slot with unequal arm lengths in the ground plane, and a parasitic quasi-rectangular loop placed coplanar with the feedline. For exciting orthogonal modes with equal amplitude, a single-point feeding technique with an asymmetrical geometry of the coplanar waveguide...
-
Ce site dilution effects in the antiferromagnetic heavy fermion CeIn3
PublikacjaLa-doped intermetallic single crystals of Ce1−xLaxIn3 were synthesized via an In self-flux method throughout the entire range (x = 0–1). The prototypical heavy-fermion compound CeIn3 shows an antiferromagnetic phase transition at 10.1 K and becomes superconducting near a critical pressure where TN is completely suppressed. As the La concentration increases, Ce moments are diluted, and the lattice constant increases linearly, satisfying Vegard’s...
-
Advanced Macromodel Matrix Structure Cloning for FDTD
PublikacjaWe propose an improved macromodel-based techniquefor efficient analysis of the structures based on PhotonicCrystals (PhC). The technique involves a new structure of thecoupling matrix and advanced cloning of not only the macromodel matrices, but also the coupling matrices SE and SH.The method allows one to shorten considerably the preprocessingtime, the RAM usage and also the iterating speed of performingFDTD. With this...
-
Enhanced Spectroscopic Insight into Acceptor-Modified Barium Strontium Titanate Thin Films Deposited via the Sol–Gel Method
PublikacjaIn the present paper, composite thin films of barium strontium titanate (BaxSr1−xTiO3) with an acceptor modifier (magnesium oxide—MgO) were deposited on metal substrates (stainless steel type) using the sol–gel method. The composite thin films feature BaxSr1−xTiO3 ferroelectric solid solution as the matrix and MgO linear dielectric as the reinforcement, with MgO concentrations ranging from 1 to 5 mol%. Following thermal treatment...
-
Hydrogen and chalcogen bonds in crystals of chalcogenadiazolecarboxylic acids – competition or cooperation?
PublikacjaThis article presents crystal structures of chalcogenadiazolecarboxylic acids bearing both a hydrogen and a chalcogen bond donor. The selected molecules varied in the size of the aromatic unit, the chalcogen atom and/or the position of the carboxyl group in the core structure. The most common synthons in their lattice are "R" _"2" ^"2" (8) self-complementary acid dimers or four-membered [Ch···N]2 rings. Supramolecular synthons...
-
Dirac fermions and possible weak antilocalization in LaCuSb2
PublikacjaLayered heavy-metal square-lattice compounds have recently emerged as potential Dirac fermion materials due to bonding within those sublattices. We report quantum transport and spectroscopic data on the layered Sb square-lattice material LaCuSb2. Linearly dispersing band crossings, necessary to generate Dirac fermions, are experimentally observed in the electronic band structure observed using angle-resolved photoemission spectroscopy,...
-
Wykorzystanie potencjometrów cyfrowych do testowania metod dynamicznej spektroskopii impedancyjnej
PublikacjaPrzedmiotem artykułu jest opracowanie modelu układu elektrochemicznego o zmiennej w czasie impedancji. Do konstrukcji modelu wykorzystano potencjometry cyfrowe sterowane mikrokontrolerem, pozwala to programowo kontrolować zmiany impedancji modelu. Odpowiednie ukształtowanie zmian widm impedancyjnych w funkcji czasu (impedancjogramów) pozwala na ustalenie ograniczeń różnych metod pomiaru impedancji.
-
Performance of zinc-rich coatings evaluated using AFM-based electrical properties imaging
PublikacjaThe paper presents the results of investigation of polyvinyl zinc-rich coating exposed to 97% relativehumidity atmosphere for 40 days. Condition of the coating and evolution of its protective properties weredetermined with the novel AFM-based approach capable of providing surface profiles, local dc currentmaps as well as local impedance spectra. The proposed technique allowed insight into the local changesof coating topography...
-
Methodology of Selecting the Optimal Receptor to Create an Electrochemical Immunosensor for Equine Arteritis Virus Protein Detection
PublikacjaThe study reports a methodology of selecting the optimal receptor to create an electrochemical immunosensor for equine arteritis virus (EAV) protein detection. The detection was based on antigen recognition by antibodies immobilized on gold electrodes. Modification steps were controlled by electrochemical impedance spectroscopy and cyclic voltammetry measurements. In order to obtain the impedance immunosensor with the best parameters,...
-
Influence of electropolymerization conditions on the morphological and electrical properties of PEDOT film
PublikacjaIn this work the effects of electropolymerization conditions on the morphological properties and conductivity of poly(3,4-ethylenedioxythiophene) (PEDOT) film have been studied. PEDOT films were electrochemically synthesized in a one step process from acetonitrile solution containing 3,4-ethylenedioxythiophene (EDOT) and lithium perchlorate. Based on atomic force microscopy, scanning electron microscopy, cyclic voltammetry and...
-
Non-isolated resonant quasi-Z-source network DC–DC converter
PublikacjaA novel non-isolated resonant quasi-impedance (quasi-Z)-source network DC–DC converter is proposed. The resonant impedance source network is derived from the quasi-Z-source network by including the autotransformer-based resonant cell instead of the second inductor of the quasi-Z-network. The leakage inductance of the autotransformer and two resonant capacitors connected in series with the autotransformer windings constitute a high-frequency...
-
Modelling of dielectric properties of BiNbO4-based microwave ceramics
PublikacjaIn the present paper results of the studies devoted to computer simulations of dielectric response of electroceramics in a frequency domain as well as analysis of the experimental data are given. As an object of investigations BiNbO4-based microwave ceramics was taken. Simulations of the hypothetical impedance response of the ceramic system were performed under assumption of the brick-layer model. A strategy for analysis and modelling...
-
Heterogeneous oxidation of highly boron-doped diamond electrodes and its influence on the surface distribution of electrochemical activity
PublikacjaThe electrochemical active surface area (EASA) of polycrystalline boron-doped diamond (BDD) electrodes is heterogeneous and can be affected by numerous factors. There is a strong need for proper consideration of BDD heterogeneity in order to improve this material's range of application in electrochemistry. Localized changes in surface termination due to the influence of oxidation agent result in increased surface resistance. The...
-
Reply to Comment on ‘Nanodiamond incorporated human liver mimicking phantoms: prospective calibration medium of magnetic resonance imaging’
PublikacjaDependence of the spin–lattice (T1) relaxation times on the nanodiamond concentration in human liver phantoms is discussed. Factors affecting stability and and reproducibility of these phantoms are presented. The need for comparative measurements on multiple MRI scanners for better understanding of potential variations in the obtained imaging data is emphasised.
-
Przegląd sposobów pomiaru pętli zwarcia
PublikacjaW metrologii obserwuje się ciągły rozwój metod i przyrządów do pomiaru impedancji pętli zwarcia. Wynika to zarówno z faktu, iż pomiar impedancji pętli zwarcia bezpośrednio związany jest z bezpieczeństwem użytkowania urządzeń elektrycznych, jak również z rozwoju nowych technologii.W publikacji przedstawiono rozwój sposobów pomiaru impedancji pętli zwarcia, od rozwiązań najstarszych po współcześnie stosowane.
-
Pomiary impendancji w warunkach ekstremalnych
PublikacjaW artykule zaprezentowano wybrane zagadnienia pomiaru impedancji w warunkach ekstremalnych. Jako takie należy rozumieć bardzo niskie lub bardzo wysokie wartości modułu impedancji, dużą dysproporcję składowych impedancji lub złożony schemat zastępczy, w którym wpływ elementów poszukiwanych jest maskowany przez inne pasożytnicze elementy. Omówiono rozwiązania sprzętowe jak też metody i algorytmy pomiarowe.
-
Sulfur compounds: Gas chromatography
PublikacjaSulfur compounds, due to their properties, are responsible for the damage of our environment. For this reason sulfur containing compounds are of constant concern in many fields. Gas chromatography (GC), due to combination of separation capability and sensitive detection is a prime technique for the analysis of thes compounds in various matrices. The chapter rewies general problems of the determination of these compounds by GC and...
-
Reduction of Computational Complexity in Simulations of the Flow Process in Transmission Pipelines
PublikacjaThe paper addresses the problem of computational efficiency of the pipe-flow model used in leak detection and identification systems. Analysis of the model brings attention to its specific structure, where all matrices are sparse. With certain rearrangements, the model can be reduced to a set of equations with tridiagonal matrices. Such equations can be solved using the Thomas algorithm. This method provides almost the same values...
-
Generalized Chebyshev Bandpass Filters With Frequency-Dependent Couplings Based on Stubs
PublikacjaThis paper presents an accurate synthesis method for inline and cross-coupled generalized Chebyshev bandpass filters with frequency-dependent couplings implemented via open and short stubs. The technique involves the synthesis of a lumped-element prototy pe in the form of a coupling matrix with a frequency-dependent term and the conversion of this prototype to a distributed-element mode l composed of sections of TEM lines. This...
-
Design and optimization of a novel miniaturized low-profile circularly polarized wide-slot antenna
PublikacjaThis paper presents a novel structure of a compact circularly polarized (CP) antenna. CP is obtained using a parasitic quasi-rectangular strip placed coplanar to the feedline. A ground plane perturbation combined with the asymmetric geometry of the coplanar waveguide ground planes is utilized to excite additional CP modes. All antenna dimensions are rigorously optimized to achieve the best possible performance in terms of the impedance...
-
Theoretical Model of Acoustic Wave Propagation in Shallow Water
PublikacjaThe work is devoted to the propagation of low frequency waves in a shallow sea. As a source of acoustic waves, underwater disturbances generated by ships were adopted. A specific feature of the propagation of acoustic waves in shallow water is the proximity of boundaries of the limiting media characterised by different impedance properties, which affects the acoustic field coming from a source situated in the water layer “ deformed”...
-
Implementation of Extended Kalman Filter with Optimized Execution Time for Sensorless Control of a PMSM Using ARM Cortex-M3 Microcontroller
PublikacjaThis paper addresses the implementation and optimization of an Extended Kalman Filter (EKF) for the Permanent Magnet Synchronous Motor (PMSM) sensorless control using an ARM Cortex-M3 microcontroller. A various optimization levels based on arithmetic calculation reduction was implemented in ARM Cortex-M3 microcontroller. The execution time of EKF estimator was reduced from 260.4 μs to 37.7 μs without loss of accuracy. To further...
-
Niskonapięciowy filtr analogowy CMOS wykorzystujący konwerter ujemnoimpedancyjny
PublikacjaA low-voltage 3-order low-pass CMOS filter based on the novel current inversion type negative impedance converter (CNIC) is presented. It shows a badwidth of 10 MHz at 400 uW power consumption and 2 V supply voltage when realized in a 0.35 um CMOS process.
-
Niskonapięciowy filtr analogowy CMOS oparty o konwerter ujemno-impedancyjny
PublikacjaA low-voltage 3-order low-pass CMOS filter based on the novel current inversion type negative impedance converter (CNIC) is presented. It shows a badwidth of 10 MHz at 400 uW power consumption and 2 V supply voltage when realized in a 0.35 um CMOS process.
-
Rapid multi-objective optimization of antennas using nested kriging surrogates and single-fidelity EM simulation models
PublikacjaEver increasing performance requirements make the design of contemporary antenna systems a complex and multi-stage process. One of the challenges, pertinent to the emerging application areas but also some of the recent trends (miniaturization, demands for multi-functionality, etc.), is the necessity of handling several performance figures such as impedance matching, gain, or axial ratio, often over multiple frequency bands. The...
-
Sodium nitrite as a corrosion inhibitor of copper in simulated cooling water
PublikacjaThe corrosion inhibition behavior of sodium nitrite (NaNO2) towards pure copper (99.95%) in simulated cooling water (SCW) was investigated by means of electrochemical impedance spectroscopy (EIS) and dynamic electrochemical impedance spectroscopy (DEIS). NaNO2 interferes with metal dissolution and reduce the corrosion rate through the formation or maintenance of inhibitive film on the metal surface. Surface morphologies illustrated...
-
Chronographic Imprint of Age-Induced Alterations in Heart Rate Dynamical Organization
PublikacjaBeat-to-beat changes in the heart period are transformed into a network of increments between subsequent RR-intervals, which enables graphical descriptions of short-term heart period variability. Three types of such descriptions are considered: (1) network graphs arising from a set of vertices and directed edges, (2) contour plots of adjacency matrices A, representing the networks and transition matrices T, resulting from A, and (3)...
-
An Analysis of Periodic Arrangements of Cylindrical Objects of Arbitrary Convex Cross Sections with the Use of Field Matching Method
PublikacjaA problem of electromagnetic wave scattering from multilayered frequency selective surfaces is presented. Each surface is composed of periodically arranged cylindrical posts of arbitrary convex cross-section. The method of analysis is based on the direct field matching technique for a single cell, and the transmission matrix method with the lattice sums technique for periodic arrangement of scatterers.
-
Directed percolation effects emerging from superadditivity of quantum networks
PublikacjaEntanglement-induced nonadditivity of classical communication capacity in networks consisting of quantum channels is considered. Communication lattices consisting of butterfly-type entanglement-breaking channels augmented, with some probability, by identity channels are analyzed. The capacity superadditivity in the network is manifested in directed correlated bond percolation which we consider in two flavors: simply directed and...
-
Weak Solutions within the Gradient-Incomplete Strain-Gradient Elasticity
PublikacjaIn this paper we consider existence and uniqueness of the three-dimensional static boundary-value problems in the framework of so-called gradient-incomplete strain-gradient elasticity. We call the strain-gradient elasticity model gradient-incomplete such model where the considered strain energy density depends on displacements and only on some specific partial derivatives of displacements of first- and second-order. Such models...
-
Macromodeling techniques for accelerated finite element analysis
PublikacjaThis paper deals with the Model Order Reduction applied locally in the Finite Element Method (FEM) analysis. Due to the reduction process, blocks of FEM system matrices associated with selected subregions of the computational domain are projected onto the subspaces spanned by the vectors of suited orthogonal projection basis. In effect, large and sparse FEM matrices are replaced with small and dense ones, called macromodels. This...
-
Identification et modélisation d'ordre fractionnaire des machines synchrones fonctionnant comme générateur
PublikacjaW pracy przedstawiono oryginalny model matematyczny generatora synchronicznego wykorzystujący pochodne rzędów niecałkowitych. W przeciwieństwie do modeli klasycznych, zbudowanych z dużej liczby drabinek R-L, zawiera on impedancje rzędu połówkowego, które pozwalają w dokładny sposób opisać zjawiska indukcji elektromagnetycznej w szerokim zakresie częstotliwości, minimalizując jednocześnie rząd i liczbę parametrów modelu. Zaproponowany...
-
Thin-walled frames and grids - statics and dynamics
PublikacjaFrames and grids assembled with thin-walled beams of open cross-section are widely applied in various civil engineering and vehicle or machine structures. Static and dynamic analysis of theses structures may be carried out by means of different models, startingfrom the classical models made of beam elements undergoing the Kirchhoff assumptions to the FE discretization of whole frame into plane elements. The former model is very...
-
Metoda wektorowa pomiaru impedancji pętli zwarciowej w obecności załóceń.** 2002, 116 s. 44 rys. 3 tab. bibliogr. 122 poz. maszyn. Rozprawa doktorska (2002.05.07), Wydz. EiA, P. Gdań. Promotor: dr hab. inż. R. Roskosz, prof. nadzw. PG.
Publikacja.
-
Wpływ uwarunkowań rzeczywistych na pracę równoległego filtru aktywnego sterowanego ze sprzężeniem od prądu zasilającego
PublikacjaW artykule przedstawiono wpływ uwarunkowań rzeczywistych na pracę równoległego filtru aktywnego i zdolność kompensacji prądów harmonicznych. Zbadano wpływ opóźnień czasowych wynikających z implementacji cyfrowej sterowania, wpływ impedancji zwarciowej sieci zasilającej oraz błędów generowania napięcia przekształtnika na jakość kompensacji filtru. Badania symulacyjne przeprowadzono dla trzech układów sterowania: otwartego, zamkniętego...
-
Study of Aliphatic Polyurethanes by the Low-Field 1H NMR Relaxometry Method with the Inversion of the Integral Transformation
PublikacjaIn this paper, the distributions of the 1H nuclear magnetic resonance (NMR) spin–lattice and spin–spin relaxation times are used to characterize the mobility of different sections of macromolecules of aliphatic polyurethanes and the cross-linking density of polymer chains. The NMR relaxometry method with inversion of integral transformation is applied to study the effect of poly (ethylene glycol) and glycerol phosphate calcium...
-
AFM-assisted investigation of conformal coatings in electronics
PublikacjaPurpose – This paper aims to presents a new method of investigation of local properties of conformal coatings utilized in microelectronics. Design/methodology/approach – It is based on atomic force microscopy (AFM) technique supplemented with the ability of local electrical measurements, which apart from topography acquisition allows recording of local impedance spectra, impedance imaging and dc current mapping. Potentialities...
-
Half-Order Modeling of Saturated Synchronous Machine
PublikacjaNoninteger order systems are used to model diffusion in conductive parts of electrical machines as they lead to more compact and knowledge models but also to improve their precision. In this paper a linear half-order impedance model of a ferromagnetic sheet deduced from the diffusion of magnetic field is briefly introduced. Then, from physical considerations and finite elements simulation, the nonlinear half-order impedance model...
-
Determination of time dependence of coated metal electrical and electrochemical parameters during exposure using principal component analysis
PublikacjaThe use of the principal component analysis (PCA) permits the complex and quantitative analysis of the time dependence of electrical and electrochemical parameters of coated metal obtained by fitting impedance data. So far, changes in electrical and electrochemical parameters during exposure were analyzed independently. In this way, some of the information contained in the relationship between changes in parameters over time are...
-
A Simple-Topology Compact Broadband Circularly Polarized Antenna With Unidirectional Radiation Pattern
PublikacjaIn this letter, a geometrically simple, reflector-backed single-point-fed circularly polarized (CP) antenna with unidirectional radiation pattern is presented. The structure comprises a simple coplanar waveguide (CPW) feeding circuit with an open slot etched on one side of the coplanar ground. The enhanced CP bandwidth is obtained by combining the loop mode, the slot mode, and the asymmetrical configuration of the coplanar ground...