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Search results for: microwave engineering
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Rapid EM-Driven Design of Compact RF Circuits By Means of Nested Space Mapping
PublicationA methodology for rapid design of RF circuits constituted by compact microstrip resonant-cells (CMRCs) is presented. Our approach exploits nested space mapping (NSM) technology, where the inner SM layer is used to correct the equivalent circuit model at the CMRC level, whereas the outer layer enhances the coarse model of the entire structure under design. We demonstrate that NSM dramatically improves performance of surrogate-based...
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Wideband Macromodels in Finite Element Method
PublicationThis letter proposes a novel projection technique for accelerating Finite Element Method simulations. The algorithm is based on the Second-order Arnoldi Method for Passive Order Reduction (SAPOR). It involves generation of two projection bases and thanks to this it is applicable to the systems of equations, which contain the quadratic frequency-dependence in the input term, that arise when projection is applied locally in the selected...
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Model Order Reduction for Problems With Dispersive Surface Boundary Conditions
PublicationThis letter proposes a new scheme for reduced-order finite-element modeling of electromagnetic structures with nonlinear, dispersive surface boundary conditions, which optimally exploits the numerically stable and efficient MOR framework for second-order systems provided by SAPOR method. The presented results of numerical experiments for an example of a waveguide filter demonstrate the superior accuracy of the resulting reduced models...
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Coupled-Resonator Waveguide Filter in Quadruplet Topology With Frequency-Dependent Coupling - A Design Based on Coupling Matrix
PublicationThis letter presents an application of a recently developed coupling matrix synthesis technique to design of coupled-resonator filters with dispersive inter-resonator couplings. This technique is used to design a novel coupled-cavity bandpass filter. Measurements validate the design and confirm effectiveness of the synthesis method. The filter is a four-pole generalized Chebyshev filter with three transmission zeros. Resonators...
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Greedy Multipoint Model-Order Reduction Technique for Fast Computation of Scattering Parameters of Electromagnetic Systems
PublicationThis paper attempts to develop a new automated multipoint model-order reduction (MOR) technique, based on matching moments of the system input–output function, which would be suited for fast and accurate computation of scattering parameters for electromagnetic (EM) systems over a wide frequency band. To this end, two questions are addressed. Firstly, the cost of the wideband reduced model generation is optimized by automating a...
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Simulation and Experiment of a Compact Wideband 90^{circ} Differential Phase Shifter
PublicationArtykuł przedstawia projekt i analizę kompaktowego różnicowego przesuwnika fazy, który jest rozwinięciem konfiguracji zaproponowanej Abbosha poprzez modyfikację obciążenia wrót. Zaproponowana konfiguracja zawiera 3dB sprzęgacz kierunkowy z wrotami transmisyjnymi i sprzężonymi zakończonymi obciążeniami reaktancyjnymi. W artykule przedstawiono model teoretyczny prezentujący zasadę działania układu i jego projekt. Uzyskane wyniki...
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Coupled-resonator filters with frequency-dependent couplings: coupling matrix synthesis
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An Analysis of Multistrip Line Configuration on Elliptical Cylinder
PublicationA configuration of multistrip lines mounted on a multilayer dielectric coated elliptic cylinder is investigated in this paper. A full-wave analysis and a moment-method calculation are employed. The analysis is carried out considering the expansion of the field as a series of Mathieu functions. Both open and shielded lines are considered in the analysis. Propagation coefficients and characteristic impedances are calculated for the...
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Low-order models from FD-TD time samples
PublicationNiniejszy artykuł zawiera opis szeregu kryteriów pozwalających na automatyczne tworzenie wysokiej jakości modeli sygnałów czasowych uzyskanych w drodze symulacji obwodów wysokiej częstotliwości metodą różnic skończonych w dziedzinie czasu. Podany jest szczegółowy opis selekcji kluczowych parametrów modeli takich jak wybór długości ciągu użytego do konstrukcji modeli, współczynnika decymacji silnie nadpróbkowanego przebiegu w dziedzinie...
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Reduced order models of refined Yee´s cells.
PublicationArtykuł opisuje nowe podejście zwiększające dokładność metody różnic skończonych za pomocą lokalnego zagęszczenia siatki. Obszar niewiele większy niż pojedyncza komórka Yee jest pokrywany gęstą siatką, a jej makromodel jest stworzony metodą redukcji rzędu modelu równań stanu w dziedzinie częstotliwości. Makromodele są użyte w metodach różnic skończonych w dziedzinie częstotliwości i czasu całej struktury. Inaczej niż w przypadku...
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Efficient analysis of waveguide componets using a hybrid PEE-FDFD algorithm.
PublicationZaproponowano przyspieszenie analizy podzespołów falowodowych poprzez połączenie metody różnic skończonych w dziedzinie częstotliwości FDFD oraz rozwinięcia w funkcje własne PEE. Proponowane sformułowanie pozwala jawnie zdefiniować operator macierzowy dla zadanego problemu. Proponowana technika została zaprezentowana zarówno dla problemów własnych jak i układów z pobudzeniem.
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Scattering in junction by posts consisting of a segment of conducting cy linder.
PublicationWykorzystując zmodyfikowaną procedurę iteracyjną i metodę dopasowania rodzajów opracowano teorię rozpraszania fali elektromagnetycznej w złączu falowodowym na obiektach będących wycinkami metalowego cylindra. W wyniku analizy uzyskano wielorodzajową macierz rozproszenia złącza falowodowego zawierającego opisywane elementy. Zarówno zmiana położenia jak i obrót elementu w złączu powoduje zmianę jego parametrów elektrycznych....
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Efficient implementation of the Cauchy method for automated CAD-model construction.
PublicationW artykule przedstawiona została efektywna metoda konstrukcji wieloparametrycznych modeli układów mikrofalowych na podstawie wyników symulacji pełnofalowej. Algorytm wykorzystuje metodę najmniejszych kwadratów (TLS) do rozwiązania problemu interpolacyjnego i automatycznie dobiera rząd modelu.Przydatność i dokładność metody jest pokazana na przykładzie projektowania filtru z wykorzystaniem modeli trzech i pięciu zmiennych.
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Finite-difference analysis of a loaded hemispherical resonator
PublicationPrzedstawiono analizę osiowo symetrycznej struktury otwartego rezonatora he-misferycznego zawierającego warstwowe ośrodki dielektryczne. W analizie wy-korzystano metodę różnic skończonych w dziedzinie częstotliwości (FDFD). Wcelu osiągnięcia wysokiej dokładności obliczeń zastosowano zaawansowane me-tody modelowania warunków brzegowych i granicznych.
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Low-Cost Method for Internal Surface Roughness Reduction of Additively Manufactured All-Metal Waveguide Components
PublicationIn this study, a novel low-cost polishing method for internal surface roughness reduction of additively manufactured components, developed for waveguide (WG) circuits operating in the millimeter frequency range is proposed. WG components fabricated using powder bed fusion (PBF) generally feature roughness of ten to fifty microns, which influences the increase of roughness-related conductor power losses having a major effect on...
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Gradient-based optimization of filters using FD-TD software
PublicationW artykule opisane jest nowe podejście do zagadnienia optymalizacji filtrów mikrofalowych pasmowo-przepustowych. Optymalizacja prowadzona jest z wykorzystaniem metody gradientowej poszukiwania minimum wartości funkcji celu oraz przy założeniu pełnofalowej symulacji obwodów metodą różnic skończonych w dziedzinie czasu. W artykule pokazane jest, że stosując zaawansowane techniki cyfrowego przetwarzania sygnałów możliwa jest optymalizacja...
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Comments on ''An innovative fast powerful method for tackling electromagnetic eigenvalue problems for multistrip transmission lines''
PublicationPraca stanowi komentarz do publikacji Casanuevy i Garcii dotyczącej techniki szybkiego obliczania charakterystyk dyspersyjnych falowodów z niejednorodnym wypełnieniem. Zwrócono uwagę na niepotrzebną komplikację zagadnienia poprzez zastosowanie techniki rozkładu na wartości szczególne.
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Characterization of rectangular waveguide with a pseudochiral omega slab
PublicationMetodę dopasowania rodzajów zastosowano do rozwiązania falowodu prostokątnego zawierającego materiał pseudochiralny typy Omega. Zdefiniowano własności rodzajów pola w badanej prowadnicy oraz zauważono wystąpienie efektu przemieszczenia pola. Określono pełnofalową macierz rozproszenia sekcji badanego falowodu oraz porównano wyniki symulacji charakterystyk transmisyjnych sekcji z eksperymentem. W oparciu o uzyskane wyniki dokonano...
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Automated CAD of coupled resonator filters
PublicationGradientowa metoda optymalizacji wraz z nową definicją funkcji celu opartą na rozkładzie biegunów oraz zer funkcji transmitancji obwodu, została zastosowana do pełnofalowej syntezy filtrów falowodowych pasmowo-przepustowych. Ekstrakcja biegunów wykonywana jest w oparciu metodę Cauchyłego. Przestawiona technika pozwana na znalezienie wymiarów geometrycznych struktur filtrujących o zadanej topologii bez konieczności wcześniejszej...
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Coupled - mode design of ferrite loaded coupled microstrip lines section
PublicationMetodę rodzajów sprzężonych zastosowano do analizy i projektowania sekcji ferrytowych mikropaskowych linii sprzężonych magnesowanych podłużnie (FCL). W wyniku analizy określono macierz rozproszenia sekcji oraz warunki umożliwiające jej zastosowanie do realizacji cyrkulatora projetowanego jako połączenie badanej sekcji FCL z mikropaskowym rozgałęzieniem typu T. W oparciu o opracowane oprogramowanie przeprowadzono modelowanie parametrów...
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Quasi-static finite-element analysis of a skewed microstrip crossover
PublicationPrzedstawiono quasi statyczną analizę skrzyżowania mikroskopowego na podłożu dielektycznym. Mikropaski znajdują się na różnych warstwach układu planarnego i mogą krzyżować się pod dowolnym kątem. Pojemności i indukcyjności obliczane są na podstawie rozkładu potencjałów skalarnych. W sformułowaniu zagadnienia magnestatycznego warunki brzegowe dla potencjału skalarnego wprowadzono za pomocą powierzchni rozcięcia dziedziny analizy....
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A new class of eigenfunction expansion methods for fast frequency-domain analysis of waveguides
PublicationZaprezentowano nową technikę szybkiego obliczania charakterystyk dyspersyjnych falowodów z niejednorodnym wypełnieniem. Metoda ta oblicza przybliżone wartości stałej propagacji dla wymaganej częstotliwości, bazując na bardziej dokładnych wyliczeniach rozkładu pola i stałej propagacji dla kilku wybranych punktów częstotliwości.
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Edge-Guided Mode Performance and Applications in Nonreciprocal Millimeter-Wave Gyroelectric Components
PublicationThe analogies between the behavior of gyromagnetic and gyroelectric nonreciprocal structures, the use of the simple transfer matrix approach, and the edge-guided (EG) wave property, supported in a parallel plate model for integrated magnetized semiconductor waveguide, are investigated in those frequency regions, where the effective permittivity is negative or positive. As with their ferrite counterparts, the leakage of the EG waves...
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A Stabilized Complex LOBPCG Eigensolver for the Analysis of Moderately Lossy EM Structures
PublicationThis letter proposes a stabilized locally optimal block preconditioned conjugate gradient method for computing selected eigenvalues for complex symmetric generalized non-Hermitian eigenproblems. Effectiveness of the presented approach is demonstrated for a moderately lossy dual-mode dielectric resonator, modeled using finite-element method with higher order elements
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Compact Quasi-Elliptic-Type Inline Waveguide Bandpass Filters With Nonlinear Frequency-Variant Couplings
PublicationThis work presents the design techniques to synthesize a class of compact inline quasi-elliptic-type waveguide cavity bandpass filters based on novel nonlinear frequency-variant couplings (NFVCs). These highly dispersive frequency-variant couplings (FVCs) are realized by means of a pair of partial-height posts that are placed at the junctions between every two cavity resonators. Each NFVC produces a transmission pole in between...
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Revisiting Toroidal Dipolar Moment in Planar Metamaterial
PublicationThis article revisits the electric, magnetic, and toroidal dipolar moments in the metamaterial structure and presents the flatland design for generating a toroidal dipolar response for the electromagnetic plane wave at normal incidence. Based on the numerical analysis of the surface current, the electric field, the magnetic field, and the quantitative analysis of scattered power supported by the electromagnetic multipole theory,...
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A Novel Modal Technique for Time and Frequency Domain Analysis of Waveguide Components
PublicationW pracy zaprezentowano, nową i szybką metodę analizy komponentów falowodowych. Metoda opiera się na kombinacji metody różnic skończonych, metody dekompozycji dziedziny obliczeniowej, redukcji rzędu modelu oraz dyskretnych rozwinięć funkcyjnych. Przedstawiona technika pozwala na skrócenie czasu analizy układu nawet o dwa rzędy wielkości w stosunku do poprzednich algorytmów.
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Design of Microwave Lossy Filter Based on Substrate Integrated Waveguide (SIW)
PublicationIn this letter, we propose a lossy three-pole Chebyshev filter centered at 5.15 GHz, based on the substrate integrated waveguide (SIW) with scattering characteristics shifted down by 5.68 dB. The filter is composed of three directly coupled SIW cavities with three lossy couplings between nonadjacent resonators. These additional couplings are realized using mixed coupled slot and microstrip lines connected with metal electrode leadless...
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Ionic liquids for nano- and microstructures preparation. Part 2: Application in synthesis
PublicationIonic liquids (ILs) are widely applied to prepare metal nanoparticles and 3D semiconductor microparticles. Generally, they serve as a structuring agent or reaction medium (solvent), however it was also demonstrated that ILs can also play a role of a co-solvent, metal precursor, reducing as well as surface modifying agent. The crucial role and possible types of interactions between ILs and growing particles have been presented in...
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Low-cost multi-objective design of compact microwave structures using domain patching
PublicationA good compromise between size and electrical performance is an important design consideration for compact microwave structures. Comprehensive information about size/performance trade-offs can be obtained through multi-objective optimization. Due to considerable electromagnetic (EM) cross-couplings in highly compressed layouts, the design process has to be conducted at the level of high-fidelity EM analysis which is computationally...
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Accumulation of radioisotopes and heavy metals in selected species of mushrooms
PublicationSeven species of forest mushrooms from different regions of Poland (edible: Imleria badia, Cantharellus cibarius, Xerocomus subtomentosus, Suillus luteus and inedible by humans but being food for animals: Paxillus involutus, Tylopilus felleus and Russula emetica) were analyzed for radioisotope activity (Cs-137, K-40, Bi-214 and Pb-210) as well as concentrations of heavy metals (aluminum, chromium, cadmium, manganese, iron, lead,...
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Metamaterial-Based Sub-Microwave Electromagnetic Field Energy Harvesting System
PublicationThis paper presents the comprehensive analysis of the sub-microwave, radio frequency band resonant metastructures’ electromagnetic properties with a particular emphasis on the possibility of their application in energy harvesting systems. Selected structures based on representative topologies of metamaterials have been implemented in the simulation environment. The models have been analyzed and their substitute average electromagnetic...
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Microscale diamond protection for a ZnO coated fiber optic sensor
PublicationFiber optic sensors are widely used in environmental, biological and chemical sensing. Due to the demanding environmental conditions in which they can be used, there is a risk of damaging the sensor measurement head placed in the measuring field. Sensors using nanolayers deposited upon the fiber structure are particularly vulnerable to damage. A thin film placed on the surface of the fiber end-face can be prone to mechanical damage...
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In-situ monitoring of electropolymerization processes at boron-doped diamond electrodes by Mach-Zehnder interferometer
PublicationIn this work, the Mach-Zehnder interferometer was designed to monitor the electrochemical processes conducted at boron-doped diamond electrode surface. The diamond electrodes were synthesized via Microwave Plasma-Assisted Chemical Vapor Deposition on optical grade quartz glass. The achieved transmittance in working are of diamond electrodes reached 55 %. A cage system-based Mach-Zehnder interferometer was used which allowed the...
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Spatial characterization of H 2: CH 4 dissociation level in microwave ECR plasma source by fibre-optic OES
PublicationSpatially 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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Coplanar Waveguide-Fed Broadband Microwave Devices with (or without) a Thin Dielectric Substrate for Use in Flexible Electronic Systems
PublicationTwo 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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Optically transparent boron-doped nanocrystalline diamond films for spectroelectrochemical measurements on different substrates
PublicationFabrication process of optically transparent boron nanocrystalline diamond (BNCD) electrode on silicon and quartz substrate was shown. The B-NCD films were deposited on the substrates using Microwave Plasma Assisted Chemical Vapor Deposition (MWPACVD) at glass substrate temperature of 475 ºC. A homogenous, continuous and polycrystalline surface morphology with high sp3 content in B-NCD films and film thickness depending from substrate...
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Rapid dimension scaling of compact microwave couplers with power split correction
PublicationIn this paper, a technique for rapid re-design ofcompact microwave couplers with respect to operating frequency is discussed. Our methodology involves an inverse surrogate model setup using several reference designs optimized (at the level of equivalent circuit representation of the coupler) for a set of operating frequencies within a range of interest. The surrogate establishes the relationship between the operating frequency...
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Monitoring and analytics of semivolatile organic compounds (SVOCs) in indoor air
PublicationThis paper reviews literature information on the behaviour of semivolatile organic compounds (SVOCs) in the indoor environment, as well as the most likely emission sources. The consecutive stages of analytical procedures used for monitoring SVOCs in indoor environments are described. The most common approaches used for collecting samples from the gas and particulate phases are mentioned. The paper discusses and compares various...
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Multi-objective optimization of microwave couplers using corrected domain patching
PublicationPractical design of microwave components and circuits is a compromise between various, often conflicting objectives. In case of compact structures, the trade-offs are typically concerned with the circuit size and its electrical performance. Comprehensive information about the best possible trade-offs can be obtained by means of multi-objective optimization. In this paper, we propose a computationally efficient technique for identifying...
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Electricity generation from rapeseed straw hydrolysates using microbial fuel cells
PublicationRapeseed straw is an attractive fuel material for microbial fuel cells (MFCs) due to its high content of carbohydrates (more than 60% carbohydrates). This study has demonstrated that reducing sugars can be efficiently extracted from raw rapeseed straw by combination of hydrothermal pretreatment and enzymatic hydrolysis followed by utilization as a fuel in two-chamber MFCs for electrical power generation. The most efficient method...
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A novel hierarchically-porous diamondized polyacrylonitrile sponge-like electrodes for acetaminophen electrochemical detection
PublicationA novel composite electrode material consisting of tangled fibrous polyacrylonitrile-based hierarchically-struc- tured nanocomposites has been produced by wet-spinning, carbonized and decorated with a carbon nano- architecture by microwave plasma-enhanced chemical vapor deposition and investigated as a metal-free electrode for the enhanced electrochemical detection of acetaminophen. Surprisingly, the hierarchical fiber ar- chitecture...
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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
PublicationIn 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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Incorporation of nitrogen in diamond films – A new way of tuning parameters for optical passive elements
PublicationThis paper investigates the impact of nitrogen incorporation in diamond films for the construction of an interferometric sensor to measure displacement. Diamond films with different nitrogen levels (0–5%) were deposited on silicon substrates by microwave plasma enhanced chemical vapor deposition. The structural characteristics of these samples are characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), confocal...
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Influence of processing conditions on crystal structure of BiNbO 4 ceramics
PublicationBismuth niobate (BiNbO4) has attracted attention as a low-fired ceramics with promising microwave application potential. It belongs to the bismutocolumbite oxides with similarly to scheelite-like stibiotantalite structure (SbTaO4) A3+B5+O4. Aim of the present research was to fabricate BiNbO4 ceramics by solid state reaction route from the mixture of simple oxides viz. Bi2O3, and Nb2O5, and study its phase composition as well as...
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The influence of sterilization with EnbioJet Microwave Flow Pasteurizer on composition and bioactivity of aronia and blue-berried honeysuckle juices
PublicationIn this study, fruit juices that are rich sources of anthocyanins, obtained from aronia (Am. chokeberry, Aronia melanocarpa) and blueberry honeysuckle (Lonicera caerulea L. var. edulis) were used to examine the preservation of plant phytochemicals and bioactivity upon sterilization -either thermal, or with an EnbioJet microwave flow pasteurizer. The chemical properties verified included determinations of anthocyanins and other...
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Optoelectronic system for monitoring of thin diamond layers growth
PublicationDevelopment of the optoelectronic system for monitoring of diamond/DLC (Diamond-Like-Carbon) thin films growth during mu PA ECR CVD (Microwave Plasma Assisted Electron Cyclotron Resonance Chemical Vapour Deposition) process is described. The multi-point Optical Emission Spectroscopy (OES) and Raman spectroscopy were employed as non-invasive optoelectronic tools. Dissociation of H-2 molecules, excitation and ionization of hydrogen...
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An Efficient Framework For Fast Computer Aided Design of Microwave Circuits Based on the Higher-Order 3D Finite-Element Method
PublicationIn 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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Application of boron-doped diamond film and ZnO layer in the Fabry-Pérot interferometer
PublicationIn this article there have been presented the use of boron-doped diamond films for sensor applications. The low-finesse Fabry-Pérot interferometer working in the reflective mode has been implemented. Two kinds of reflective layers have been elaborated: boron-doped diamond thin films and zinc-oxide (ZnO) layer. Thin ZnO layers were deposited by Atomic Layer Deposition (ALD) on the face of a standard telecommunication single-mode...
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Soxhlet Extraction and New Developments Such as Soxtec in: Comprehansive Sampling and Sample Preparation
PublicationSoxhlet extraction is one of the most popular techniques for extraction of analytes from solid materials. Since its discovery in 1879, the standard Soxhlet technique has been routinely applied in almost every analytical laboratory. Up to this day, Soxhlet extraction technique remains a standard technique to which the performance of modern extraction techniques is compared.Over the years, an intensive research on different modifications...