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wszystkich: 285
Wyniki wyszukiwania dla: INTERPOLATION DISCRETE FOURIER TRANSFORM (DFT)
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The effect of current signal filtering method on the value of cutting power while sawing wood
PublikacjaThe goal of this work was to investigate an effect of various signal pre-processings on the outline of the electrical power curve and its influence on the measured cutting force estimation. Two signal processing methods were selected for the needs of the experiment, including digital filter and wavelet transform. The filter used was Butterworth, 3rd order band-stop with the cut-out band from 45 Hz to 55 Hz. The second approach...
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Chirp-rate estimation of FM signals in the time-frequency domain
PublikacjaNovel dynamic representations of a complex signal in the time-frequency domain including: a channelized instantaneous complex frequency (CICF), a complex local group delay (CLGD) and a channelized instantaneous chirp-rate (CICR) are introduced. The proposed approach is based on the use of the gradient of the short-time Fourier transform complex phase. An interpretation of the newly-introduced distributions especially of the CICR...
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Research 1: Heterojunction of (P, S) co-doped g-C3N4 and 2D TiO2 for improved carbamazepine and acetaminophen photocatalytic degradation
Dane BadawczeThe first research article consisted on the synthesis of phosphorus and sulfur co-doped graphitic carbon nitride incorporated in 2D TiO2 structure for solar-driven degradation of emerging pollutants from the group of pharmaceuticals not susceptible to biodegradation. The hybrid photocatalysts with different loadings of (P, S)-doped g-C3N4 were characterized...
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Lamb wave-based monitoring of shear failure of an adhesive lap joint
PublikacjaThe paper presents a study on the elastic wave propagation in adhesive joints of steel plates subjected to tensile loading. A single lap joint was chosen for analysis because of its simplicity and plurality of applications. Experimental investigations consisted of the uniaxial extension of prepared specimens. Force and displacement values were recorded by a testing machine. Simultaneously, guided Lamb waves were excited and signals...
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A New Expression for the 3-D Dyadic FDTD-Compatible Green's Function Based on Multidimensional Z-Transform
PublikacjaIn this letter, a new analytic expression for the time-domain discrete Green's function (DGF) is derived for the 3-D finite-difference time-domain (FDTD) grid. The derivation employs the multidimensional Z-transform and the impulse response of the discretized scalar wave equation (i.e., scalar DGF). The derived DGF expression involves elementary functions only and requires the implementation of a single function in the multiple-precision...
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Optical and photocatalytic properties of rare earth metal-modified ZnO quantum dots
PublikacjaA series of novel ZnO quantum dots modified with rare earth metals was successfully prepared by a simple sol-gel approach. The effects of types (Eu, Er, Tb, Yb, Ho, La) and amounts (from 0.09 to 0.45 mmol) of lanthanides on the optical properties, structural characterization and photocatalytic activity of ZnO/RE QDs were systematically investigated. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform...
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Power of the low alpha brainwaves in the mental imagery experiment in sport: the "Your Home Venue" scenario.
Dane BadawczeThe data were collected to perform research on the neural oscillation during mental imagery in sport. The study's main aim was to examine the cortical correlations of imagery depending on instructional modality (guided vs self-produced) using various sport-related scripts. The research was based on the EEG signals recorded during the session with the...
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Power of the low alpha brainwaves in the mental imagery experiment in sport: the "Slow Start" scenario.
Dane BadawczeThe data were collected to perform research on the neural oscillation during mental imagery in sport. The main aim of the study was to examine the cortical correlates of imagery depending on instructional modality (guided vs self-produced) using various sport-related scripts. The research was based on the EEG signals recorded during the session with...
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Power of the SMR brainwaves in the mental imagery experiment in sport: the "Start in High Level Championship" scenario.
Dane BadawczeThe data were collected to perform research on the neural oscillation during mental imagery in sport. The main aim of the study was to examine the cortical correlates of imagery depending on instructional modality (guided vs self-produced) using various sport-related scripts. The research was based on the EEG signals recorded during the session with...
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Power of the low alpha brainwaves in the mental imagery experiment in sport: the "Successful Competition" scenario.
Dane BadawczeThe data were collected to perform research on the neural oscillation during mental imagery in sport. The study's main aim was to examine the cortical correlations of imagery depending on instructional modality (guided vs self-produced) using various sport-related scripts. The research was based on the EEG signals recorded during the session with the...
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Power of the high alpha brainwaves in the mental imagery experiment in sport: the "Your Home Venue" scenario.
Dane BadawczeThe data were collected to perform research on the neural oscillation during mental imagery in sport. The study's main aim was to examine the cortical correlations of imagery depending on instructional modality (guided vs self-produced) using various sport-related scripts. The research was based on the EEG signals recorded during the session with the...
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Power of the SMR brainwaves in the mental imagery experiment in sport: the "Fitness Activity" scenario.
Dane BadawczeThe data were collected to perform research on the neural oscillation during mental imagery in sport. The main aim of the study was to examine the cortical correlates of imagery depending on instructional modality (guided vs self-produced) using various sport-related scripts. The research was based on the EEG signals recorded during the session with...
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Power of the SMR brainwaves in the mental imagery experiment in sport: the "Slow Start" scenario.
Dane BadawczeThe data were collected to perform research on the neural oscillation during mental imagery in sport. The main aim of the study was to examine the cortical correlates of imagery depending on instructional modality (guided vs self-produced) using various sport-related scripts. The research was based on the EEG signals recorded during the session with...
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Power of the high alpha brainwaves in the mental imagery experiment in sport: the "Training Session" scenario.
Dane BadawczeThe data were collected to perform research on the neural oscillation during mental imagery in sport. The study's main aim was to examine the cortical correlations of imagery depending on instructional modality (guided vs self-produced) using various sport-related scripts. The research was based on the EEG signals recorded during the session with the...
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Power of the SMR brainwaves in the mental imagery experiment in sport: the "Successful Competition" scenario.
Dane BadawczeThe data were collected to perform research on the neural oscillation during mental imagery in sport. The study's main aim was to examine the cortical correlations of imagery depending on instructional modality (guided vs self-produced) using various sport-related scripts. The research was based on the EEG signals recorded during the session with the...
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Power of the SMR brainwaves in the mental imagery experiment in sport: the "Training Session" scenario.
Dane BadawczeThe data were collected to perform research on the neural oscillation during mental imagery in sport. The study's main aim was to examine the cortical correlations of imagery depending on instructional modality (guided vs self-produced) using various sport-related scripts. The research was based on the EEG signals recorded during the session with the...
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Power of the low alpha brainwaves in the mental imagery experiment in sport: the "Training Session" scenario.
Dane BadawczeThe data were collected to perform research on the neural oscillation during mental imagery in sport. The study's main aim was to examine the cortical correlations of imagery depending on instructional modality (guided vs self-produced) using various sport-related scripts. The research was based on the EEG signals recorded during the session with the...
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Power of the high alpha brainwaves in the mental imagery experiment in sport: the "Slow Start" scenario.
Dane BadawczeThe data were collected to perform research on the neural oscillation during mental imagery in sport. The main aim of the study was to examine the cortical correlates of imagery depending on instructional modality (guided vs self-produced) using various sport-related scripts. The research was based on the EEG signals recorded during the session with...
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Power of the high alpha brainwaves in the mental imagery experiment in sport: the "Successful Competition" scenario.
Dane BadawczeThe data were collected to perform research on the neural oscillation during mental imagery in sport. The study's main aim was to examine the cortical correlations of imagery depending on instructional modality (guided vs self-produced) using various sport-related scripts. The research was based on the EEG signals recorded during the session with the...
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Power of the SMR brainwaves in the mental imagery experiment in sport: the "Your Home Venue" scenario.
Dane BadawczeThe data were collected to perform research on the neural oscillation during mental imagery in sport. The study's main aim was to examine the cortical correlations of imagery depending on instructional modality (guided vs self-produced) using various sport-related scripts. The research was based on the EEG signals recorded during the session with the...
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Power of the high alpha brainwaves in the mental imagery experiment in sport: the "Fitness Activity" scenario.
Dane BadawczeThe data were collected to perform research on the neural oscillation during mental imagery in sport. The main aim of the study was to examine the cortical correlates of imagery depending on instructional modality (guided vs self-produced) using various sport-related scripts. The research was based on the EEG signals recorded during the session with...
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Power of the low alpha brainwaves in the mental imagery experiment in sport: the "Fitness Activity" scenario.
Dane BadawczeThe data were collected to perform research on the neural oscillation during mental imagery in sport. The main aim of the study was to examine the cortical correlates of imagery depending on instructional modality (guided vs self-produced) using various sport-related scripts. The research was based on the EEG signals recorded during the session with...
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Wavelet Transform Analysis of Temperature Modulated Gas Sensor Response
PublikacjaThe aim of the study was to evaluate whether it is possible to extract the information about the gas concentration despite the influence of humidity. Commercial semiconductor sensor response was examined under the application of a periodic temperature change. The data was collected using measurement protocol for different concentrations of ammonia at specified levels of relative humidity. In this work we focused on the evaluation...
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Running characteristics of aerodynamic bearing with self-lifting capability at low rotational speed
PublikacjaAn aerodynamic journal bearing that is capable of self-generating squeeze-film pressure is presented and its dynamic characteristics investigated numerically and experimentally. A numerical method based on a time marching static model was applied to assess the orbit trajectory path of the rotor upon a perturbation. Experimental results were obtained to validate the effect of the self- generated squeeze-film pressure on the stability...
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Improvement of Fingerprinting Method based on Hill Cipher by using Frequency Domain
PublikacjaThe main goal of this paper is to present the advantages of a digital fingerprinting in a frequency domain over a pixel domain, in case of VoD services (Video on Demand). The paper presents basic issues of a multimedia data protection by digital fingerprinting. It also describes threats to embedded fingerprints from both collusion attacks and from a transmission itself. Possible solution was presented on the example of the DCT...
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Power of the high alpha brainwaves in the mental imagery experiment in sport: the "Start in High Level Championship" scenario.
Dane BadawczeThe data were collected to perform research on the neural oscillation during mental imagery in sport. The main aim of the study was to examine the cortical correlates of imagery depending on instructional modality (guided vs self-produced) using various sport-related scripts. The research was based on the EEG signals recorded during the session with...
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Power of the low alpha brainwaves in the mental imagery experiment in sport: the "Start in High Level Championship" scenario.
Dane BadawczeThe data were collected to perform research on the neural oscillation during mental imagery in sport. The main aim of the study was to examine the cortical correlates of imagery depending on instructional modality (guided vs self-produced) using various sport-related scripts. The research was based on the EEG signals recorded during the session with...
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Self-Testing of Analog Parts Terminated by ADCs Based on Multiple Sampling of Time Responses
PublikacjaA new approach for self-testing of analog parts terminated by analog-to-digital converters in mixed-signal electronic microsystems controlled by microcontrollers is presented. It is based upon a new fault diagnosis method using a transformation of the set of voltage samples of the time response of a tested analog part to a square impulse into localization curves placed in a multidimensional measurement space. The method can be used...
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A complete impedance analysis of electrochemical cells used as energy sources
PublikacjaA comprehensive description of impedance ofelectrochemical systems has been presented, along withthe assumptions of the method used. In this method, amultisinusoidal current excitation signal is used. Thechanges of potential of both the electrodes and thepotential difference between these electrodes are allregistered simultaneously as a function of time. Theproposed method offers the possibility of separatelydetermining the instantaneous...
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Synergistic Effects of Bitumen Plasticization and Microwave Treatment on Short-Term Devulcanization of Ground Tire Rubber
PublikacjaGround tire rubber (GTR) was mechano-chemically modified with road bitumen 160/220 and subsequently treated using a microwave radiation. The combined impact of bitumen 160/220 content and microwave treatment on short-term devulcanization of GTR was studied by thermal camera, wavelength dispersive X-ray fluorescence spectrometry (WD-XRF), static headspace, and gas chromatography-mass spectrometry (SHS-GC-MS), thermogravimetric analysis...
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Chirp Rate and Instantaneous Frequency Estimation: Application to Recursive Vertical Synchrosqueezing
PublikacjaThis letter introduces new chirp rate and instantaneous frequency estimators designed for frequency-modulated signals. These estimators are first investigated from a deterministic point of view, then compared together in terms of statistical efficiency. They are also used to design new recursive versions of the vertically synchrosqueezed short-time Fourier transform, using a previously published method (D. Fourer, F. Auger, and...
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Comparison of noise reduction methods in radiometric correlation measurements of two-phase liquid-gas flows
PublikacjaTwo-phase liquid-gas flows occur frequently in the mining, energy, chemical, and petrochemical industries. One of non-contact methods used to analyse these flows is the gamma ray absorption method. However, the signals received from radiation detectors contain a significant stochastic noise, which makes them difficult to analyse. The article describes four methods of noise reduction in cross-correlation measurements of water-air...
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Wykorzystanie fazy transformaty STFT do oceny jakości spektrogramu
PublikacjaW niniejszej publikacji przedstawiono koncepcję oceny jakości spektrogramu, wykorzystując często marginalizowaną fazę transformaty STFT (ang. Short-term Fourier transform). Spektrograf traktowany jest jako bank filtrów demultipleksujących sygnał. Dla każdego w ten sposób odfiltrowanego sygnału składowego obliczana jest kanałowa pulsacja chwilowa (ang. channel instantaneous frequency) oraz lokalne opóźnienie grupowe (ang. local...
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Double ZIF-L structures with exceptional CO2 capacity
PublikacjaCarbon dioxide emission is an emerging problem nowadays and new methods are designed for its control. In this article, a report on the formation of zeolitic imidazole framework with an apparent double leaf-like morphology DZIF-L is given. The special structure of the materials prevents from aggregation of the particles providing remarkable CO2 capacity. At 0.1 MPa the CO2 uptake was 2.99 ± 0.06 mmol/g. The capacity of synthesized...
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A fast time-frequency multi-window analysis using a tuning directional kernel
PublikacjaIn this paper, a novel approach for time-frequency analysis and detection, based on the chirplet transform and dedicated to non-stationary as well as multi-component signals, is presented. Its main purpose is the estimation of spectral energy, instantaneous frequency (IF), spectral delay (SD), and chirp rate (CR) with a high time-frequency resolution (separation ability) achieved by adaptive fitting of the transform kernel. We...
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Selection of excitation signals for high-impedance spectroscopy
PublikacjaA method of fast impedance spectroscopy of technical objects with high impedance (|Zx| > 1 GOhm) is evaluated in this paper. An object is excited with a signal generated by a digital-to-analog converter (DAC) located on the U2531A DAQ module. Response signals proportional to current flowing through and voltage across the measured object are sampled by analog-to-digital converters (ADC) in the DAQ module. The object impedance spectrum...
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Studies on the influence of β-cyclodextrin derivatives on the physical stability of famotidine
PublikacjaThe usage of Fourier transform infrared spectroscopy, near infrared spectroscopy, differential scanning calorimetry and microscopy is presented in this work focused on the exploration of the effect of CD on the physical stability of famotidine (FAM). The most significant information was achieved by analysis of the second derivatives ofnear infrared (NIR) spectra recorded. Changes in the shape of spectra derivatives allow...
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Application of vibrational spectroscopy, thermal analyses and X-Ray diffraction in the rapid evaluation of the stability in solid-state of ranitidine, famotidine and cimetidine
PublikacjaThis paper reports the study on applicability of Fourier transform infrared (FTIR), near-infrared (NIR) and Raman spectroscopy, differential scanning calorimetry (DSC) and X-ray diffraction (XRD) for the estimation of the chemical stability and photostability of histamine H2-receptor antagonist substances. Ranitidine hydrochloride (RAN), famotidine (FAM) and cimetidine (CIM) were tested and differences in sensitivity were measured...
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Sprzętowa implementacja koprocesora dla zastosowań kryptograficznych
PublikacjaW pracy przedstawiono procedurę implementacji elektronicznej skrzynki podawczej z wykorzystaniem zasobów sprzętowych na płytce FPGA (Filed Programmable Gate Array) typu Virtex 4. Przedstawiono ogólna zasadę działania skrzynki podawczej oraz opisano parametry i właściwości poszczególnych modułów funkcjonalnych systemu tj.: modułu TFTP Trivia File Transfer Protocol), serwera WWW, funkcji skrótu oraz asymetrycznego algorytm kryptograficznego....
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Determination of phenylbutazone, sulfamethazine, carbendazim and linuron using a novel pine bark biosorbent for solid-phase extraction (SPE) with high-performance liquid chromatography (HPLC)
PublikacjaThe paper presents a novel pine bark based biosorbent for solid-phase extraction (SPE). The morphology and composition of the pine bark were characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The biosorbent was used for the preparation of wastewater for the determination of phenylbutazone, sulfamethazine, carbendazim, and linuron by high performance liquid chromatography with...
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Efficient signal processing in spectroscopic optical coherence tomography
PublikacjaSpectroscopic optical coherence tomography (SOCT) is an extension of a standard OCT technique, which allows to obtain depth-resolved, spectroscopic information on the examined sample. It can be used as a source of additional contrast in OCT images e.g. by encoding certain features of the light spectrum into the hue of the image pixels. However, SOCT require computation of time-frequency distributions of each OCT A-scan, what is...
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The instantaneous frequency rate spectogram
PublikacjaAn accelerogram of the instantaneous phase of signal components referred to as an instantaneous frequency rate spectrogram (IFRS) is presented as a joint time-frequency distribution. The distribution is directly obtained by processing the short-time Fourier transform (STFT) locally. A novel approach to amplitude demodulation based upon the reassignment method is introduced as a useful by-product. Additionally, an estimator of energy...
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Two-step Conversion of Crude Glycerol Generated by Biodiesel Production into Biopolyols: Synthesis, Structural and Physical Chemical Characterization
PublikacjaIn this work biopolyols were synthesized via two-step process from crude glycerol and castor oil. For better evaluation of analyzed process, the impact of its time and temperature on the structure and properties of biopolyols was determined. Obtained results fully justified conducting of synthesis in two steps. Prepared materials were characterized by hydroxyl value and water content comparable to polyols industrially applied in...
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Offshore surface waters of Antarctica are free of microplastics, as revealed by a circum-Antarctic study
PublikacjaIn 2018, during a circum navigation of Antarctica below 62° S by the sailing boat Katharsis II, the presence of plastics was investigated with surface sampling nets at ten evenly spaced locations (every 36° of longitude). Although fibres that appeared to be plastic (particles up to 2 cm) were found in numbers ranging from 1 particle (0.002 particles per m3) to 171 particles (1.366 particles per m3) per station, a Fourier-transform...
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Luminescent properties of Ln3+ doped tellurite glasses containing AlF3
PublikacjaThe low-phonon energy tellurite glasses TeO2-BaO-Bi2O3 and TeO2-BaO-Bi2O3-AlF3 triply doped with Eu3+, Tb3+, Tm3+ ions in two different molar ratios were synthesized using melt-quenching technique. Their structure and luminescence properties were widely investigated by X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR) and Photoluminescence Spectroscopy (PL). The luminescence...
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Use of Ginger Nanofibers for the Preparation of Cellulose Nanocomposites and Their Antimicrobial Activities
PublikacjaHere, we report, for the first time, the isolation of ginger nanofibers (GNF) from ginger rhizomes spent by acid hydrolysis and followed by high-pressure homogenization. Scanning electron microscopy was utilized to identify the surface morphology of the GNF and the widths ranged between 130 to 200 nm. Structural analysis of GNF was identified by Fourier transform infrared spectroscopy, Differential scanning calorimetry, and X-ray...
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Method for Clustering of Brain Activity Data Derived from EEG Signals
PublikacjaA method for assessing separability of EEG signals associated with three classes of brain activity is proposed. The EEG signals are acquired from 23 subjects, gathered from a headset consisting of 14 electrodes. Data are processed by applying Discrete Wavelet Transform (DWT) for the signal analysis and an autoencoder neural network for the brain activity separation. Processing involves 74 wavelets from 3 DWT families: Coiflets,...
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Analysis of radiation and scattering problems with the use of hybrid techniques based on the discrete Green's function formulation of the FDTD method
PublikacjaIn this contribution, simulation scenarios are presented which take advantage of the hybrid techniques based on the discrete Green's function formulation of the finite-difference time-domain (DGF-FDTD) method. DGF-FDTD solutions are compatible with the finite-difference grid and can be applied for perfect hybridization of the FDTD method. The following techniques are considered: (i) DGF-FDTD for antenna simulations, (ii) DGF-based...
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Badania eksperymentalne i symulacyjne dynamiki modelowego odcinka sieci trakcyjnej
PublikacjaW pracy przedstawiono główne założenia i strukturę opracowanego modelu matematycznego odcinka kolejowej górnej sieci trakcyjnej, opartego na metodzie energetycznej Lagrange’a. W celu wyznaczenia wybranych parametrów modelu, jak również dla oceny stopnia zgodności odwzorowania przez utworzony program symulacyjny stanów statycznych i dynamicznych sieci zbudowano laboratoryjny model odcinka sieci jezdnej z użyciem rzeczywistych jej...
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Spectroscopic Study of Plasma Polymerized a-C:H Films Deposited by a Dielectric Barrier Discharge
PublikacjaPlasma polymerized a-C:H thin films have been deposited on Si (100) and aluminum coated glass substrates by a dielectric barrier discharge (DBD) operated at medium pressure using C2Hm/Ar (m = 2, 4, 6) gas mixtures. The deposited films were characterized by Fourier transform infrared reflection absorption spectroscopy (FT-IRRAS), Raman spectroscopy, and ellipsometry. FT-IRRAS revealed the presence of sp3 and sp2 C–H stretching and...