Filtry
wszystkich: 834
wybranych: 729
Wyniki wyszukiwania dla: COMPLEMENTARY RESONATOR, CALIBRATION, DIELECTRIC CHARACTERIZATION, HIGH SENSITIVITY, MICROWAVE SENSOR
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Mikropompa elektrohydrodynamiczna na ciecz dielektryczną zasilana napięciem stałym
PublikacjaW niniejszym artykule zaprezentowano projekt i działanie miniaturowej pompy elektrohydrodynamicznej (EHD) zasilanej napięciem stałym przeznaczonej do chłodzenia elementów elektronicznych. Zmierzono natężenie przepływu cieczy oraz ciśnienie wytwarzane przez pracującą mikropompę. Maksymalne natężenie przepływu, 0,5 ml/min, uzyskano dla napięcia 12 kV. Zmierzone ciśnienie wyniosło 500 Pa przy przyłożonym napięciu 6 kV. Maksymalny...
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Electrical characterization of diamond/boron doped diamond nanostructures for use in harsh environment applications
PublikacjaThe polycrystalline boron doped diamond (BDD) shows stable electrical properties and high tolerance for harsh environments (e.g. high temperature or aggressive chemical compounds) comparing to other materials used in semiconductor devices. In this study authors have designed electronic devices fabricated from non-intentionally (NiD) films and highly boron doped diamond structures. Presented semiconductor devices consist of highly...
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Zarządzanie zaufaniem w bezprzewodowych sieciach czujników - studium przypadku
PublikacjaW artykule przedstawiono studium przypadku dotyczące zastosowania bezprzewodowej sieci czujników do wspomagania pacjenta z nadwagą w jego środowisku domowym. Przyjęto, że sieć wykorzystuje metodę rozproszonego zarządzania zaufaniem i pokazano, że metoda ta umożliwia wykrycie i izolację czujników realizujących działania sprzeczne z polityką sieci. Ilościowe oszacowanie czasu niezbędnego do wykrycia takich...
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Long-Period Gratings and Microcavity In-Line Mach Zehnder Interferometers as Highly Sensitive Optical Fiber Platforms for Bacteria Sensing
PublikacjaSelected optical fiber sensors offer extraordinary sensitivity to changes in external refractive (RI), which make them promising for label-free biosensing. In this work the most sensitive ones, namely long-period gratings working at (DTP-LPG) and micro-cavity in-line Mach-Zehnder interferometers (µIMZI) are discussed for application in bacteria sensing. We describe their working principles and RI sensitivity when operating in water...
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Zero-Pole Electromagnetic Optimization
PublikacjaA fast technique for the full-wave optimization of transmission or reflection properties of general linear timeinvariant high-frequency components is proposed. The method is based on the zeros and poles of the rational function representing the scattering parameters of the device being designed and it is the generalization of the technique developed for the design by optimization of microwave filters. The performance of the proposed...
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Residue-Pole Methods for Variability Analysis of S-parameters of Microwave Devices with 3D FEM and Mesh Deformation
PublikacjaThis paper presents a new approach for variability analysis of microwave devices with a high dimension of uncertain parameters. The proposed technique is based on modeling an approximation of system by its poles and residues using several modeling methods, including ordinary kriging, Adaptive Polynomial Chaos (APCE), and Support Vector Machine Regression (SVM). The computational cost is compared with the traditional Monte-Carlo...
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Detection of the Incoming Sound Direction Employing MEMS Microphones and the DSP
PublikacjaA 3D acoustic vector sensor based on MEMS microphones and its application to road traffic monitoring is presented in the paper. The sensor is constructed from three pairs of digital MEMS microphones, mounted on the orthogonal axes. Signals obtained from the microphones are used to compute sound intensity vectors in each direction. With this data, it is possible to compute the horizontal and vertical angle of an incoming sound....
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Local response surface approximations and variable-fidelity electromagnetic simulations for computationally efficient microwave design optimisation
PublikacjaIn this study, the authors propose a robust and computationally efficient algorithm for simulation-driven design optimisation of microwave structures. Our technique exploits variable-fidelity electromagnetic models of the structure under consideration. The low-fidelity model is optimised using its local response surface approximation surrogates. The high-fidelity model is refined by space mapping with polynomial interpolation of...
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Deep neural networks for human pose estimation from a very low resolution depth image
PublikacjaThe work presented in the paper is dedicated to determining and evaluating the most efficient neural network architecture applied as a multiple regression network localizing human body joints in 3D space based on a single low resolution depth image. The main challenge was to deal with a noisy and coarse representation of the human body, as observed by a depth sensor from a large distance, and to achieve high localization precision....
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RECENT ADVANCES IN GRAPHENE APPLICATION FOR ELECTRONIC SENSING
PublikacjaThe great interest in graphene is caused by its potential for constructing various sensors exhibiting excellent parameters. The high carrier mobility and the unique band structure of graphene makes it promising especially in the field-effect transistors (GFET) applications. In this article, recent advances of the selected graphene-based sensor applications were presented and the possible directions for further investigations were...
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Recent Advances in Performance-Driven Surrogate Modeling of High-Frequency Structures
PublikacjaDesign of high‐frequency structures, including microwave and antenna components, heavily relies on full‐wave electromagnetic (EM) simulation models. Their reliability comes at a price of a considerable computational cost. This may lead to practical issues whenever numerous EM analyses are to be executed, e.g., in the case of parametric optimization. The difficulties entailed by massive simulations may be mitigated by the use of...
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A GPU Solver for Sparse Generalized Eigenvalue Problems with Symmetric Complex-Valued Matrices Obtained Using Higher-Order FEM
PublikacjaThe paper discusses a fast implementation of the stabilized locally optimal block preconditioned conjugate gradient (sLOBPCG) method, using a hierarchical multilevel preconditioner to solve nonHermitian sparse generalized eigenvalue problems with large symmetric complex-valued matrices obtained using the higher-order finite-element method (FEM), applied to the analysis of a microwave resonator. The resonant frequencies of the low-order...
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Model-based identification of the dominant N2O emission pathway in a full-scale activated sludge system
PublikacjaActivated sludge models (ASMs), extended with an N2O emission module, are powerful tools to describe the operation of full-scale wastewater treatment plants (WWTPs). Specifically, such models can investigate the most contributive N2O production pathways and guide towards N2O and carbon footprint (CF) mitigation measures. A common practice is to develop and validate models using data from a single WWTP. In this study, a successfully...
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Low-Cost Surrogate Modeling of Miniaturized Microwave Components Using Nested Kriging
PublikacjaIn the paper, a recently reported nested kriging methodology is employed for modeling of miniaturized microwave components. The approach is based on identifying the parameter space region that contains high-quality designs, and, subsequently, rendering the surrogate in this subset. The results obtained for a miniaturized unequal-power-split rat-race coupler and a compact three-section impedance transformer demonstrate reliability...
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High-accuracy polarimetric studies on lead germanate single crystals
PublikacjaA high-accuracy polarimetric technique has been used for the characterization of a lead germanate ferroelectric single crystal. The measurement results of the linear and circular birefringence in the [010] direction at a wavelength of 633 nm under the influence of an electric field are presented. Gyration–electric field hysteresis loops at alternative crystal positions in the polarization system have been used to determine the...
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Fiber-optic sensors based on microspheres with nanocoatings (Zastosowanie mikrosfer optycznych z cienkowarstwowymi pokryciami w czujnikach światłowodowych)
PublikacjaTemperature is one of the most important physical quantities. Temperature measurements are used in every field of life, especially electronics, electrical engineering, energy-related fields, including energy source and storage devices. The goal of this dissertation is to design and optimize the microsphere-based fiber-optic sensors construction for measurement of the sensor surrounding medium temperature, including selection of...
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Global sensitivity analysis of membrane model of abdominal wall with surgical mesh
PublikacjaThe paper addresses the issue of ventral hernia repair. Finite Element simulations can be helpful in the optimization of hernia parameters. A membrane abdominal wall model is proposed in two variants: a healthy one and including hernia defect repaired by implant. The models include many uncertainties, e.g. due to variability of abdominal wall, intraabdominal pressure value etc. Measuring mechanical properties with high accuracy...
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Arabinoxylans: A review on protocols for their recovery, functionalities and roles in food formulations
PublikacjaArabinoxylans (AXs) are compounds with high nutritional value and applicability, including prebiotics or supplementary ingredients, in food manufacturing industries. Unfortunately, the recovery of AXs may require advanced separation and integrated strategies. Here, an analysis of the emerging techniques to extract AXs from cereals and their by-products is discussed. This review covers distinct methods implemented over the last...
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Expedited Yield-Driven Design of High-Frequency Structures by Kriging Surrogates in Confined Domains
PublikacjaUncertainty quantification is an important aspect of engineering design, also pertaining to the development and performance evaluation of high-frequency structures systems. Manufacturing tolerances as well as other types of uncertainties, related to material parameters (e.g., substrate permittivity) or operating conditions (e.g., bending) may affect the characteristics of antennas or microwave devices. For example, in the case...
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Rapid dimension scaling of compact microwave couplers with power split correction
PublikacjaIn 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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A bisection‐based heuristic for rapid EM‐driven multiobjective design of compact impedance transformers
PublikacjaDesign of microwave structures is a multiobjective task where several conflicting requirements have to be considered at the same time. For contemporary circuits characterized by complex geometries, multiobjective optimization cannot be performed using standard population‐based algorithms due to high cost of electromagnetic (EM) evaluations. In this work, we propose a deterministic approach for fast EM‐driven multiobjective design...
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Behavior of residual current devices at earth fault currents with DC component
PublikacjaLow-voltage electrical installations are increasingly saturated with power electronic converters. Due to very high popularity of photovoltaic (PV) installations and the spread of electric vehicles (EV) as well as their charging installations, DC–AC and AC–DC converters are often found in power systems. The transformerless coupling of AC and DC systems via power electronic converters means that an electrical installation containing...
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Comprehensive determination of flavouring additives and nicotine in e-cigarette refill solutions. Part II: Gas-chromatography–mass spectrometry analysis
PublikacjaFlavouring compounds are an essential part of e-liquid products for cigarettes. In general, they are regarded as safe for ingestion, but they may have unrecognized risks when they are inhaled. In some cases, manufactures do not currently abide by the Tobacco Products Directive (2014/40/EU) and do not declare the detailed contents of e-liquids on their labels. To help evaluate the health impact of flavouring substances, there is...
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Fast EM-driven optimization using variable-fidelity EM models and adjoint sensitivities
PublikacjaA robust and computationally efficient technique for microwave design optimization is presented. Our approach exploits variable-fidelity electromagnetic (EM) simulation models and adjoint sensitivities. The low-fidelity EM model correction is realized by means of space mapping (SM). In the optimization process, the SM parameters are optimized together with the design itself, which allows us to keep the number...
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Sensors for Rapid Detection of Environmental Toxicity in Blood of Poisoned People
PublikacjaRecently, the diagnosis and treatment of poisoned person can be done only in specialized centers. Furthermore, currently used clinical methods of intoxication diagnosis are not sufficient for early detection. Conventional laboratory tests based on urine and blood require professional, high skilled staff, high cost equipment as well as they are arduous and lasting analytical procedures. There is a need to elaborate relatively cheap...
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Computationally Efficient Design Optimization of Compact Microwave and Antenna Structures
PublikacjaMiniaturization is one of the important concerns of contemporary wireless communication systems, especially regarding their passive microwave components, such as filters, couplers, power dividers, etc., as well as antennas. It is also very challenging, because adequate performance evaluation of such components requires full-wave electromagnetic (EM) simulation, which is computationally expensive. Although high-fidelity EM analysis...
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A Method of Fast and Simultaneous Calibration of Many Mobile FMCW Radars Operating in a Network Anti-Drone System
PublikacjaA market for small drones is developing very fast. They are used for leisure activities and exploited in commercial applications. However, there is a growing concern for accidental or even criminal misuses of these platforms. Dangerous incidents with drones are appearing more often, and have caused many institutions to start thinking about anti-drone solutions. There are many cases when building stationary systems seems to be aimless...
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Tailoring the optical parameters of optical fiber interferometer with dedicated boron-doped nanocrystalline diamond thin film
PublikacjaOptical fiber interferometer using nanocrystalline boron-doped diamond film was investigated. The diamond films were deposited on glass plates using a Microwave Plasma-Enhanced Chemical Vapour Deposition (μPE CVD) sys-tem. The growth time was 3h, with boron doping level of 10 000 ppm producing films (B-NCD-10) of thickness ~ 200 nm. The presence of boron atoms in the diamond film is evident in Raman spectrum as peaks at 1212 cm-1...
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Measurements of photoionization of mercury atoms into the 6s 2S1/2, 5d96s2 2D5/2 and 5d96s2 2D3/2 ionic states over the energy range from 10.5 eV to 18.7 eV
PublikacjaPhotoionization of mercury atoms into the three lowest ionic states, 5d106s 2S1/2, 5d96s2 2D5/2 and 5d96s2 2D3/2 has been studied in the photon energy ranges from their respective thresholds to 18.7 eV. The photoionization spectra were obtained with high energy resolution at an angle of 0° with respect to the polarization vector of the photon beam. The high energy resolution and sensitivity achieved in the measurements permitted...
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Synthesis of Titanium Dioxide via Surfactant-Assisted Microwave Method for Photocatalytic and Dye-Sensitized Solar Cells Applications
PublikacjaIn this study, titania nanoparticles were obtained using the microwave-assisted technique. Moreover, different surfactants (PEG (Mn = 400), Pluronic P123 and Triton X−100) were used during the synthesis in order to determine their impact on the crystallinity and morphology of the final products. Subsequently, techniques such as XRD, SEM and TEM (performed in high contrast and high-resolution mode), diffuse reflectance spectroscopy...
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Magnetic disturbances caused by magnetic contamination of plastics
PublikacjaIn the study of low magnetic fields precision magnetometers working in a differential system are used. Two optically pumped magnetometers working in a differential system allow for precise measuring of disturbances in the magnetic field. In order to attain high accuracy of magnetic field measurement, it is necessary to use appropriate materials for the construction of a magnetometric system, particularly of those located closely...
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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,...
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CMOS implementation of an analogue median filter for image processing in real time
PublikacjaAn analogue median filter, realised in a 0.35 μm CMOS technology, is presented in this paper. The key advantages of the filter are: high speed of image processing (50 frames per second), low-power operation (below 1.25 mW under 3.3 V supply) and relatively high accuracy of signal processing. The presented filter is a part of an integrated circuit for image processing (a vision chip), containing: a photo-sensor matrix, a set of...
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Fast Full-Wave Multilevel Zero-Pole Optimization of Microwave Filters
PublikacjaA new concept is proposed for the full-wave computer-aided design of microwave filters. The method consists of two stages and operates on the zeros and poles of the transfer function and their derivatives. These quantities are evaluated from the response computed by a full-wave electromagnetic solver with two levels of accuracy. The two stages make use of different models that are optimized using a low-accuracy electromagnetic...
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Synthesis and properties of porous Sr 0.96 Y 0.04 Ti 1−x Nb x O 3
PublikacjaA series of porous, single phase Sr0.96Y0.04Ti1-xNbxO3 samples was obtained using a wet synthesis method (modified citrate sol-gel) method. Temperature-programmed reduction (TPR) and temperature-programmed oxidation (TPO) measurements have shown high stability of the obtained material in variable (oxidizing/reducing) atmospheres. All samples exhibit high conductivity in hydrogen atmosphere with the highest value (around 1S/cm)...
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A Theoretical and Experimental Study of Moderate Temperature Alfa Type Stirling Engines
PublikacjaThe Stirling engine is a device that allows conversion of thermal energy into mechanical energy with relatively high efficiency. Existing commercial designs are mainly based on the usage of high temperature heat sources, whose availability from renewable or waste heat sources is significantly lower than that of moderate temperature sources. The paper presents the results of experimental research on a prototype alpha type Stirling...
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Surrogate modeling of impedance matching transformers by means of variable‐fidelity electromagnetic simulations and nested cokriging
PublikacjaAccurate performance evaluation of microwave components can be carried out using full‐wave electromagnetic (EM) simulation tools, routinely employed for circuit verification but also in the design process itself. Unfortunately, the computational cost of EM‐driven design may be high. This is especially pertinent to tasks entailing considerable number of simulations (eg, parametric optimization, statistical analysis). A possible...
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Performance-Driven Surrogate Modeling of High-Frequency Structures
PublikacjaThe development of modern high-frequency structures, including microwave and antenna components, heavily relies on full-wave electromagnetic (EM) simulation models. Notwithstanding, EM-driven design entails considerable computational expenses. This is especially troublesome when solving tasks that require massive EM analyzes, parametric optimization and uncertainty quantification be-ing representative examples. The employment of...
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Instrumental measurement of odour nuisance in city agglomeration using electronic nose
PublikacjaThe paper describes an operation principle of odour nuisance monitoring network in a city agglomeration. Moreover, it presents the results of investigation on ambient air quality with respect to odour obtained during six-month period. The investigation was carried out using a network comprised of six prototypes of electronic nose and Nasal Ranger field olfactometers employed as a reference method. The monitoring network consisted...
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What is in a name: Defining “high entropy” oxides
PublikacjaABSTRACT High entropy oxides are emerging as an exciting new avenue to design highly tailored functional behaviors that have no traditional counterparts. Study and application of these materials are bringing together scientists and engineers from physics, chemistry, and materials science. The diversity of each of these disciplines comes with perspectives and jargon that may be confusing to those outside of the individual fields,...
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High Temperature Corrosion Evaluation of Porous Hastelloy X Alloy in Air and Humidified Hydrogen Atmospheres
PublikacjaIn this work a commercially available porous Hastelloy X alloy is characterized in terms of high temperature corrosion resistance. The alloy was oxidized in the temperature range from 500C to 900C in air and humidified hydrogen for 100 hours. Corrosion rates and porosity changes were measured. Microstructural characterization was performed using X-ray diffractometry and scanning electron microscopy. Results show that porous alloys...
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Application of boron-doped diamond film and ZnO layer in the Fabry-Pérot interferometer
PublikacjaIn 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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Electrochemical glucose sensor based on the glucose oxidase entrapped in chitosan immobilized onto laser-processed Au-Ti electrode
PublikacjaThe study on novel electrode material composed of structured titanium foil with embedded Au nanoparticles and modified with chitosan with entrapped glucose oxidase is presented. To confirm the successful immobilization of glucose oxidase FT-IR analysis was performed. The response of electrodes were tested towards glucose in the presence of different interference compounds and biological fluids. The prepared material exhibits excellent...
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A material model of asphalt mixtures based on Monte Carlo simulations
PublikacjaThe paper aims to numerically reflect mineral-asphalt mixture structure by a standard FEM software. Laboratory test results are presented due to bending tests of circular notched elements. The result scatter is relatively high. An attempt was made to form a random aggregate distribution in order to obtain various results corresponding to laboratory tests. The material structure calibration, its homogenization and finite element...
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Deep compaction control of sandy soils
PublikacjaVibroflotation, vibratory compaction, micro-blasting or heavy tamping are typical improvement methods for the cohesionless deposits of high thickness. The complex mechanism of deep soil compaction is related to void ratio decrease with grain rearrangements, lateral stress increase, prestressing effect of certain number of load cycles, water pressure dissipation, aging and other effects. Calibration chamber based interpretation...
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Organic Vapor Sensing Mechanisms by Large-Area Graphene Back-Gated Field-Effect Transistors under UV Irradiation
PublikacjaThe gas sensing properties of graphene back-gated field-effect transistor (GFET) sensors toward acetonitrile, tetrahydrofuran, and chloroform vapors were investigated with the focus on unfolding possible gas detection mechanisms. The FET configuration of the sensor device enabled gate voltage tuning for enhanced measurements of changes in DC electrical characteristics. Electrical measurements were combined with a fluctuation-enhanced...
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Critical review of electronic nose and tongue instruments prospects in pharmaceutical analysis
PublikacjaElectronic nose (enose, EN) and electronic tongue (etongue, ET) have been designed to simulate human senses of smell and taste in the best possible way. The signals acquired from a sensor array, combined with suitable data analysis system, are the basis for holistic analysis of samples. The efficiency of these instruments, regarding classification, discrimination, detection, monitoring and analytics of samples in different types...
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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,...
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Efficiency Evaluation of High Performance Computing Systems Using Data Envelopment Analysis
PublikacjaThe paper presents an evaluation method of high performance computing (HPC) systems using multicriteria efficiency analysis. The Data Envelopment Analysis approach was applied and adapted to the specifics of HPC, which enabled us to compare relative efficiency of systems considering simultaneously multiple parameters. The analysis is based on the TOP500 list of world largest supercomputers and their parameters such as: the number...
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On deterministic procedures for low-cost multi-objective design optimization of miniaturized impedance matching transformers
PublikacjaPurpose This paper aims to investigate deterministic strategies for low-cost multi-objective design optimization of compact microwave structures, specifically, impedance matching transformers. The considered methods involve surrogate modeling techniques and variable-fidelity electromagnetic (EM) simulations. In contrary to majority of conventional approaches, they do not rely on population-based metaheuristics, which permit lowering...