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Wyniki wyszukiwania dla: MICROWAVE/RF CIRCUIT
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Coplanar Waveguide-Fed Broadband Microwave Devices with (or without) a Thin Dielectric Substrate for Use in Flexible Electronic Systems
PublikacjaTwo examples of microwave devices, fed by a coplanar waveguide and realized on a thin substrate (or without such a substrate), are employed to investigate the influence of devices’ curvatures and the proximity of different materials on their parameters. To perform the tests, a broadband antenna and a low-pass filter are chosen. A feeding coplanar waveguide is realized on a dielectric material brick attached to an SMA connector...
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Linear antenna microwave chemical vapour deposition of diamond films on long-period fiber gratings for bio-sensing applications
PublikacjaThe growth processes of nanocrystalline diamond (NCD) thin films on fused silica optical fibers with UV-induced long-period gratings (LPGs) were investigated with regard to biosensing applications. The films were deposited using a linear antenna microwave plasma enhanced chemical vapor deposition system, which allows for the growth of diamond at temperatures below 350°C. The films exhibited a high refractive index n = 2.32, as...
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Evaluation of the potential of Microwave Plasma–Atomic Emission Spectrometry for trace elements leaching assessment from the concrete matrix with sewage sludge ash additives
PublikacjaThe management of ash generated during the thermal utilization of sewage sludge is a significant environmental problem requiring an effective technological solution. One alternative way to dispose of sewage sludge is to bind it in concrete as a substitute for part of the aggregate. The properties of the C-S-H phase enable effective immobilization of harmful substances that sewage sludge contains. The amount of individual compounds...
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Surface modification of PMMA polymer and its composites with PC61BM fullerene derivative using an atmospheric pressure microwave argon plasma sheet
PublikacjaThis paper presents the results of experimental investigations of the plasma surface modification of a poly(methyl methacrylate) (PMMA) polymer and PMMA composites with a [6,6]-phenyl-C61-butyric acid methyl ester fullerene derivative (PC61BM). An atmospheric pressure microwave (2.45 GHz) argon plasma sheet was used. The experimental parameters were: an argon (Ar) flow rate (up to 20 NL/min), microwave power (up to 530 W), number...
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Design and Experimental Validation of a Metamaterial-Based Sensor for Microwave Imaging in Breast, Lung, and Brain Cancer Detection
PublikacjaThis study proposes an innovative geometry of a microstrip sensor for high-resolution microwave imaging (MWI). The main intended application of the sensor is early detection of breast, lung, and brain cancer. The proposed design consists of a microstrip patch antenna fed by a coplanar waveguide with a metamaterial layer-based lens implemented on the back side, and an artificial magnetic conductor (AMC) realized on as a separate...
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Some methods of diagnosis of analog circuit using mixed signal test bus IEEE 1149.4
PublikacjaW artykule przedstawiono wybrane metody testowania i diagnostyki analogowych układów elektronicznych zamontowanych na pakiecie pomiędzy układami scalonymi wyposażonymi w magistralę IEEE 1149.4. Prezentowane metody dobrano pod kątem stopnia skomplikowania układów testowanych oraz specyficznych właściwości metrologicznych magistrali, które ograniczają możliwości pomiarowe i aplikacyjność metod. Rozważono trzy typy układów testowanych:...
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The Impact of Lightning Flashes and Sprites on the Earth’s Global Electric Circuit: An Overview of Recent Modeling Results
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A method of self-testing of an analog circuit terminated by an ADC in electronic embedded systems controlled by microcontrollers
PublikacjaA new self-testing method of analog parts terminated by an ADC in electronic embedded systems controlled by microcontrollers is presented. It is based on a new fault diagnosis method based on on-line (i.e. during measurement), transformations of voltage samples of the time response of a tested part to a square pulse - onto localization curves placed in the measurement space. The method can be used for fault detection and single...
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Spatial characterization of H 2: CH 4 dissociation level in microwave ECR plasma source by fibre-optic OES
PublikacjaSpatially resolved optical emission spectroscopy (SR-OES) was used to investigate microwave activated H2/Ar/CH4 plasma under conditions of the electron cyclotron resonance (ECR). The chemistry and composition of the gas phase were studied using self-designed fibre-optic system with echelle type spectrometer during CVD deposition of polycrystalline diamond. One-dimensional intensity profiles of the main species were collected along...
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Tuning of the Electrochemical Properties of Transparent Fluorine-doped Tin Oxide Electrodes by Microwave Pulsed-plasma Polymerized Allylamine
PublikacjaWe report here the dry, one-step, and low-temperature modification of FTO surfaces using pulsed plasma polymerization of allylamine (PPAAm). PPAAm/FTO surfaces were characterized by X-ray photoelectron spectroscopy, spectroscopic ellipsometry, and contact angles to understand the morphological, structural, and optical properties. FTO were coated with a very thin layer of adherent cross-linked, pinhole-, and additive-free allylamine...
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An Efficient Framework For Fast Computer Aided Design of Microwave Circuits Based on the Higher-Order 3D Finite-Element Method
PublikacjaIn this paper, an efficient computational framework for the full-wave design by optimization of complex microwave passive devices, such as antennas, filters, and multiplexers, is described. The framework consists of a computational engine, a 3D object modeler, and a graphical user interface. The computational engine, which is based on a finite element method with curvilinear higher-order tetrahedral elements, is coupled with built-in...
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Low-cost performance-driven modelling of compact microwave components with two-layer surrogates and gradient kriging
PublikacjaUtilization of electromagnetic (EM) simulation tools has become indispensable for reliable evaluation of microwave components. As the cost of an individual analysis may already be considerable, the computational overhead associated with EM-driven tasks that require massive simulations (e.g., optimization) may turn prohibitive. One of mitigation methods is the employment of equivalent network models. Yet, they are incapable of accounting...
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Bean seed proteins digestibility affected by pressure and microwave cooking
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Investigations of the susceptibility of unmanned aerial vehicles on intensive microwave radiation
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Multivariate models of inter-resonator couplings for microwave filter synthesis
PublikacjaArtykuł przedstawia technikę budowy modeli częstotliwości rezonansowej, współczynnika sprzężenia między rezonatorami oraz sprzężenia ze źródłem/obciążeniem. Przedstawiony jest model siedmiu zmiennych uwzglęgniający topologię rezonatorów. Na podstawie modelu wykonana została synteza filtrów mikrofalowych.
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Study of anticorrosion and microwave absorption properties of NiZn ferrite pigments
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Y2O3:Eu nanocrystals as biomarkers prepared by a microwave hydrothermal method
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A Novel Reactor for Microwave Hydrothermal Scale-up Nanopowder Synthesis
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Microwave solvothermal synthesis and characterization of manganese-doped ZnO nanoparticles
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Hydrothermal, microwave and mechanochemical modification of amorphous zirconium phosphate structure
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A New Microwave Ceramic – Polymer Composite with 0-3 Connectivity
PublikacjaGoal of the present research was to fabricate and study two-phase BiNbO4//PVDF composites with 0-3 connectivity. Such composite consists of there-dimensionally connected polymer matrix loaded with dielectric ceramic particles. In the present case BiNbO4 powder acted as an active phase (dispersed phase) whereas polyvinylidene fluoride (PVDF) acted as a non-active (passive) phase (matrix). BiNbO4//PVDF composites with the volume...
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Design and Microwave-Assisted Synthesis of TiO2-Lanthanides Systems and Evaluation of Photocatalytic Activity under UV-LED Light Irradiation
PublikacjaThe TiO2-Eu and TiO2-La systems were successfully synthesized using the microwave method. Based on the results of X-ray diffraction analysis, it was found that regardless of the analyzed systems, two crystal structures were noted for the obtained samples: anatase and rutile. The analysis, such as XPS and EDS, proved that the doped lanthanum and europium nano-particles are present only on the TiO2 surface without disturbing the...
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EGATEC: A new high-resolution engineering model of the global atmospheric electric circuit—Currents in the lower atmosphere
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Assessing the Operation System of Fire Alarm Systems for Detection Line and Circuit Devices with Various Damage Intensities
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Hybrid analysis of microwave components in cylindrical coordinates with function expansion in subdomains.
PublikacjaW artykule zaproponowano wydajną metodę przyspieszenia analizy FDTD, poprzez podział dziedziny obliczeniowej i zastosowanie różnych algorytmów w różnych elementach dziedziny. Zaproponowano uniwersalną metodę łączenia techniki PEE (Partial Eigenfunction Expansion)i niezmodyfikowanej FDTD w jednej analizie. Uzyskano redukcję liczby zmiennych oraz wydłużenie kroku czasowego.
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Low order autoregressive (AR) models for FDTD analysis of microwave filters.
PublikacjaArtykuł opisuje zastosowanie modeli AR w celu poprawy efektywności analizy struktur filtrujących metodą różnic skończonych w dziedzinie czasu (FD-TD). Opisanych jest szereg kryteriów pozwalających na automatyczne tworzenie modeli AR sygnałów czasowych, w tym wybór fragmentu odpowiedzi układu stanowiący podstawę ekstrakcji współczynników modelu, współczynnika decymacji oraz rzędu modelu. Skuteczność wprowadzonych kryteriów...
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Accurate modelling of microwave structures using shape-preserving response prediction
PublikacjaArtykuł prezentuje metodologię dokładnego modelowania struktur mikrofalowych. Jest to zmodyfikowana wersja techniki opartej na procedurze przewidywania odpowiedzi z zachowaniem kształtu (shape-preserving response prediction, SPRP), która oszacowuje odpowiedź struktury mikrofalowej otrzymanej poprzez kosztowną obliczeniowo symulację elektromagnetyczną za pomocą taniego obliczeniowo modelu tejże struktury. Modyfikacja polega na wykorzystaniu...
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Inspection of protective linings using microwave spectroscopy combined with chemometric methods
PublikacjaOpisano nowa niedestrukcyjna metodę kontroli jakości nowych wykładzin ochronnych na podłożu metalowym oraz oceny ich stanu w trakcie eksploatacji przy zastosowaniu spektroskopii mikrofalowej w szerokim zakresie częstotliwości od 6,5 do 13 GHz. Uzyskane dane pomiarowe dodane zostały obróbce chemometrycznej w celu redukcji ilości danych doświadczalnych i wizualizacji rezultatów. Przedstawiono podstawy teoretyczne metody oraz wyniki...
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Microwave-assisted hydrothermal synthesis and electrochemical studies of α- and h-MoO3
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Microwave plasma application in decomposition and steam reforming of model tar compounds
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Paramagnetism of cobalt-doped ZnO nanoparticles obtained by microwave solvothermal synthesis
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Size control mechanism of ZnO nanoparticles obtained in microwave solvothermal synthesis
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An automated microwave planar filter design based on space mapping optimization
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Book review: Simulation-Driven Design Optimisation and Modelling for Microwave Engineering
PublikacjaCelem książki jest przedstawienie aktualnego stanu badań dotyczących projektowania układów mikrofalowych poprzez modelowanie i optymalizacje wspomagane symulacjami elektromagnetycznymi. Grupa międzynarodowych ekspertów zajmujących się rożnymi aspektami komputerowo wspomaganego projektowania układów mikrofalowych, podsumowuje i dokonuje przeglądu ostatnich osiągnięć w tej dziedzinie oraz przedstawia szereg praktycznych zastosowań....
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Best State Estimate for the Phase Angles of Busbars in Power Systems via Circuit Modeled with DC Load Flow
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Isolation of the relative decrease in magnetic permeability contribution to reluctance of an open magnetic circuit based on stray field measurements
PublikacjaThe goal of the study was to evaluate a relative decrease in magnetic permeability in open magnetic circuits based on stray magnetic field measurements. The boundary element method was used to simulate magnetic circuits with variable geometry and variable magnetic permeability. The simulated magnetic circuits were rectangular or bone-shaped flat samples. Reluctance was increased in the middle of the samples resulting in leakage...
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Inrush and short circuit current identification based on real-time spectral analysis with the use of the FPGA FFT processor
PublikacjaW artykule przedstawiono krótkookresową analize widmową prądu załączeniowego i prądu zwarciowego transformatora w czasie rzeczywistym z zastosowaniem procesora FFT zrealizowanego w FPGA. Otrzymane widmo ułatwia rozróżnienie rodzaju prądu, co może być zastosowanei do lepszego sterowania zabezpieczneiem różnicowo-prądowym. Określono tez teoretyczne przebiegi prądów dla przyjetego modelu transformatora. Przeprowadzono ponadto analizę...
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Rapid method for the determination of organochlorine pesticides and PCBs in fish muscle samples by microwave-assisted extraction and analysis of extracts by GC-ECD
PublikacjaA procedure for the multiresidue determination of organochlorine pesticides and polychlorinated biphenyls in fish muscle samples has been developed. The method is based on the microwave-assisted extraction (MAE) of food samples from an acetonitrile-water (95 + 5, v/v) mixture followed by SPE cleanup of the extracts and analysis by GC with an electron capture detector. MAE operational parameters, such as the extraction solvent,...
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Removal of metal particles from carbon nanotubes using conventional and microwave methods
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High Q-factor Microwave Fabry-Perot Resonator With Distributed Bragg Reflectors
PublikacjaZrealizowany został rezonator Fabry-Perot pracujący na częstotliwości 39 GHz i wykorzystujący dwie pary ćwierćfalowych kwarcowych reflektorów Bragga. Dla fali o długości 98.26 mm otrzymano dobroć ok. 560,000, co oznacza 4.3-krotny wzrost w porównaniu z identycznym rezonatorem bez reflektorów Bragga. Analizę problemu wykonano przy pomocy metody różnic skończonych w dziedzinie częstotliwości (FDFD) i porównano z uproszczonym rozwiązaniem...
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Compatible DC and small-signal MOSFET models for radio and microwave frequency simulation
PublikacjaZaprezentowano nowy model stałoprądowy tranzystora MOS i kompatybilny z nim uogólniony nie-quasi-statyczny model małosygnałowy. Model stałoprądowy został eksperymentalnie zweryfikowany dla tranzystorów MOS o długości kanału od 75 nm do kilkunastu mikrometrów, a model małosygnałowy od zera herców do 30 GHz.
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Size Control of Cobalt-Doped ZnO Nanoparticles Obtained in Microwave Solvothermal Synthesis
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Current Trends in the Development of Microwave Reactors for the Synthesis of Nanomaterials in Laboratories and Industries: A Review
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A Review of Microwave Synthesis of Zinc Oxide Nanomaterials: Reactants, Process Parameters and Morphologies
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New model simulations of the global atmospheric electric circuit driven by thunderstorms and electrified shower clouds: The roles of lightning and sprites
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Operational System Modelling in a Focused Fire Alarm System with an Open and Signal Detection Circuit Supervising Railway Station Premises
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Low-power microwave-induced fabrication of functionalised few-layer black phosphorus electrodes: A novel route towards Haemophilus Influenzae pathogen biosensing devices
PublikacjaIn this paper, various passivation schemes were applied at few-layer black phosphorus (FLBP) to achieve covalent functionalisation with 4-azidobenzoic acid, improving its electrochemical response intended for analytical and biosensing applications. The thermal and microwave assisted modification procedures in toluene and dime-thylformamide resulted in high reversibility of reactions on functionalised FLBP using a ferricyanide/ferrocya-nide...
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Efficient optimization approaches for microwave assisted extraction of high-quality antioxidant compounds from Salvia officinalis L.: UHPLC-HRMS differential analysis of phenolic profiles obtained by ultrasound and microwave extraction
PublikacjaThe study aims to optimize MAE of total phenolic compounds (TPC) and antioxidant capacity from Salvia officinalis L. leaves using a definitive screening design (DSD) and I-optimal design. UHPLC-HRMS analysis was used to identify and compare the composition of MAE and UAE optimal extracts. The results showed that DSD and I-optimal design were successfully applied for the optimization of MAE targeting phenolics and other antioxidants...
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Chemical and biological characterization of Ocimum basilicum L. phenolic extract and essential oil derived through ultrasound and microwave-assisted extraction techniques
PublikacjaPlant-derived bioactive molecules are increasingly utilized in food processing as natural additives, driven by a growing interest in healthier lifestyles. This trend has spurred industries to reformulate products to meet the demands of health-conscious consumers. This study investigates the phenolic extract and essential oil of O. basilicum L. obtained via ultrasound-assisted extraction and microwave-assisted extraction, respectively. Characterization...
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Multi-Fidelity Local Surrogate Model for Computationally Efficient Microwave Component Design Optimization
PublikacjaIn order to minimize the number of evaluations of high-fidelity (“fine”) model in the optimization process, to increase the optimization speed, and to improve optimal solution accuracy, a robust and computational-efficient multi-fidelity local surrogate-model optimization method is proposed. Based on the principle of response surface approximation, the proposed method exploits the multi-fidelity coarse models and polynomial interpolation...