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MPPT and GMPPT Implementation for Buck-Boost Mode Control of quasi-Z-Source Inverter
PublikacjaThe focus is on the maximum power point tracking implementation for the buck-boost voltage mode control of a single-phase multilevel inverter based on a three-level neutral point clamped quasi-Z-source topology. To utilize shoot-through states only when boost function is needed and avoid it in the buck mode, two different control approaches are required. This work proposes merged control system which provides switching between...
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Towards spectroscopic monitoring of photoelectrodes: In-situ Raman photoelectrochemistry of a TiO2/prussian blue photoanode
PublikacjaHere, novel in-situ Raman photoelectrochemical measurements are performed. The obtained results have proved that it is possible to track the progress of a photoelectrochemical reaction that takes place on a semiconducting electrode using the spectroscopic method. As an exemplary system, the Ti/TiO2/Prussian blue electrode is investigated. Since TiO2 is an n-type semiconductor, it cannot act as an efficient anode in dark conditions....
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DMSO and TMAO—Differences in Interactions in Aqueous Solutions of the K-Peptide
PublikacjaInteractions between a solvent and their co-solute molecules in solutions of peptides are crucial for their stability and structure. The K-peptide is a synthetic fragment of a larger hen egg white lysozyme protein that is believed to be able to aggregate into amyloid structures. In this study, a complex experimental and theoretical approach is applied to study systems comprising the peptide, water, and two co-solutes: trimethylamide...
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Influence of the femoral offset on the muscles passive resistance in total hip arthroplasty
PublikacjaBackground Soft tissue tension is treated as a crucial factor influencing the post-THA dislocation. The femoral offset is regarded as one of the major parameters responsible for the stabilization of the prosthesis. It is unclear which soft tissue is mostly affected by the offset changes. Methods A finite element model of the hip was created. The model comprised muscles, bones, a stem, the acetabular component and a liner. The muscles...
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Tuning the photocatalytic performance through magnetization in Co-Zn ferrite nanoparticles
PublikacjaIn this work, the link between the photocatalytic performance of Co-Zn ferrite nanoparticles and the net magnetic moment is analyzed. CoxZn1-xFe2O4 nanoparticles (0 ≤ x ≤ 1) were synthesized by co-precipitation method and different physicochemical techniques were employed to characterize the samples (X-ray diffraction, Transmission Electron Microscopy (TEM), BET surface area, Diffuse Reflectance Spectroscopy (DRS), Photoluminescence spectroscopy,...
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Rare earth ions doped K 2 Ta 2 O 6 photocatalysts with enhanced UV–vis light activity
PublikacjaNew rare earth-doped K2Ta2O6 photocatalysts were successfully synthesized by hydrothermal method. The effect of dopant type (Y,Yb,Ho,Pr,Er) and amount of rare earth precursor (2,4,8 and 10 mol%) on the physicochemical and photocatalytic properties of RE-K2Ta2O6 have been investigated. All as-prepared materials were characterized by UV–vis diffuse reflectance spectroscopy, Brunauer-Emmett-Teller specific surface area measurement,...
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Superconductivity in the Cu(Ir1-xPtx)2Se4 spinel
PublikacjaWe report the observation of superconductivity in the CuIr2Se4 spinel induced by partial substitution of Pt for Ir. The optimal doping level for superconductivity in Cu(Ir1-xPtx )2Se4 is x = 0.2, where Tc is 1.76 K. A superconducting Tc vs composition dome is established between the metallic, normal conductor CuIr2Se4 and semiconducting CuIrPtSe4. Electronic structure calculations show that the optimal Tc occurs near the electron count...
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Topological modifications for performance improvement and size reduction of wideband antenna structures
PublikacjaCompact antennas belong to the key components of modern communication systems. Their miniaturization is often achieved by introducing appropriate topological changes such as simple ground plane slots or tapered feeds. More sophisticated modifications are rarely considered in the literature because they normally lead to significant increase of the number of tunable parameters, which makes the antenna design process more challenging....
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Engineering Au nanoparticle arrays on SiO2 glass by pulsed UV laser irradiation
PublikacjaWe study semi-regular arrays of Au nanoparticles (NP) obtained via UV laser irradiation of thin Au films on glass substrate. The NP structures are prepared from films of a thickness up to 60 nm produced by discharge sputtering or pulsed laser deposition, and annealed by nanosecond laser pulses at 266 or 308 nm, respectively, at fluencies in the range of 60-410 mJ/cm2. For the rare- and close-packed NP structures, consistent description...
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Design of Microwave-Based Angular Displacement Sensor
PublikacjaThis letter presents a novel microwave-based rotation sensor having a wide dynamic range to detect and measure the angular displacement in terms of the change in resonant frequency. The proposed sensor is based on the microstrip technology, where a rotor comprised of a complementary splitring resonator (CSRR) placed on the ground plane of the microstrip line is free to rotate around its axis. The mechanical rotation of CSRR determines...
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Comparison of direct and inverse methods of satellite observations downscaling for the coastal zone area
PublikacjaThe Earth observation satellite imaging systems have known limitations, especially regarding their spatial and temporal resolution. Therefore, approaches which aim to combine data retrieved from sensors of higher temporal and lower spatial resolution with the data characterized by lower temporal but higher spatial resolution are of high interest. This allows for joint utilization of the advantages of both these types of sensors....
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Valence and Ionic Lowest-Lying Electronic States of Isobutyl Formate Studied by High-Resolution Vacuum Ultraviolet Photoabsorption, Photoelectron Spectroscopy, and Ab Initio Calculations
PublikacjaThe highest resolution vacuum ultraviolet photoabsorption spectrum of isobutyl formate, C5H10O2, yet reported is presented over the energy range 4.5−10.7 eV (275.5−118.0 nm) revealing several new spectral features. Valence and Rydberg transitions and their associated vibronic series observed in the photoabsorption spectrum have been assigned in accordance with new ab initio calculations of the vertical excitation energies and oscillator...
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Investigating BiMeVOx compounds as potential photoelectrochemical and electrochemical materials for renewable hydrogen production
PublikacjaIn this study, BiMeVOx compounds (where Me: Co, Mo, Ce, Zr) were synthesized and characterized as potential photoelectrochemical materials for solar water splitting, the hydrogen evolution reaction (HER), and oxygen evolution reaction (OER). The analysis confirmed the successful formation of phase BiMeVOx compounds with the desired crystal structure. Among the tested materials, BiCoVOx(800) showed the highest photocurrent density...
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New empirical correlations for the viscosity of selected organic phase change materials
PublikacjaAlthough there are many methods and instruments for measuring viscosity, it is still difficult to determine a reliable value of the dynamic viscosity of complex chemicals such as paraffins and fatty acids. This is due to the complex and heterogeneous structure of these compounds in the case of commercial products. On the other hand, the measuring instrument should be selected very carefully, including its measuring principle and...
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Continuous blood pressure monitoring by photoplethysmography - signal preprocessing requirements based on blood flow modelling
PublikacjaObjective. The aim of the study is to investigate the effect of the signal sampling frequency and low-pass filtering on the accuracy of the localisation of the fiducial points of the photoplethysmographic signal (PPG), and thus on the estimation of the blood pressure (i.e. the accuracy of the estimation). Approach. Statistical analysis was performed on 3,799 data samples taken from a publicly available database. Four PPGfiducial...
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Cost-Efficient Design Methodology for Compact Rat-Race Couplers
PublikacjaIn this article, a reliable and low-cost design methodology for simulation-driven optimization of miniaturized rat-race couplers (RRCs) is presented. We exploit a two-stage design approach, where a composite structure (a basic building block of the RRC structure) is first optimized using a pattern search algorithm, and, subsequently, the entire coupler is tuned by means of surrogate-based optimization (SBO) procedure. SBO is executed...
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Structure and paramagnetism in weakly correlated Y8Co5
PublikacjaWe report the basic physical properties of monoclinic Y8Co5 determined by means of magnetic susceptibility, electrical resistivity, and specific heat measurements. The crystal structure of Y8Co5 is monoclinic (P21/c) with lattice parameters a = 7.0582(6) Å, b = 7.2894(6) Å, c = 24.2234(19) Å, and β = 102.112(6)° as refined by using synchrotron powder x-ray diffraction data. The compound shows temperature independent paramagnetism...
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Probing Local Structural Changes by Sharp Luminescent Infrared Nanophosphor for Application in Light-Emitting Diodes
PublikacjaCr3+-doped infrared phosphors are promising candidates for next-generation phosphor-converted infrared light-emitting diodes (LEDs) because they can, in principle, tune and convert the luminescence spectra from an LED chip. However, most studies focus on broad-band Cr3+-doped phosphors, and the control mechanism of Cr3+-doped phosphors with sharp line emissions remains ambiguous. Here, we report LiGa5(1–x)Al5xO8:Cr3+ phosphors...
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The Way One Defines Specification Matters: On the Performance Criteria for Efficient Antenna Optimization in Aggregated Bi-Objective Setups
PublikacjaDesign of antenna structures for real-world applications is a challenging task that often involves addressing multiple design requirements at a time. Popular solution approaches to this class of problems include utilization of composite objectives. Although configuration of such functions has a significant effect on the cost and performance of the optimization, their specific structure is normally determined based on engineering...
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Radio Channel Measurements in Body-to-Body Communications in Different Scenarios
PublikacjaThis paper presents body-to-body radio channel measurements at the 2.45 GHz band, for different body motion scenarios and on-body antenna placements, and both indoor and outdoor environments. Measurement equipment, investigated scenarios and considered environments are described, an initial analysis of results being presented. The mean path loss and the standard deviation depend on the mutual location of transmitting and receiving...
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Physical properties and electronic structure of La3Co and La3Ni intermetallic superconductors
PublikacjaLa3Co and La3Ni are reported superconductors with transition temperatures of 4.5 and 6 K, respectively. Here, we reinvestigate the physical properties of these two intermetallic compounds with magnetic susceptibility χ, specific heat Cp and electrical resistivity ρ measurements down to 1.9 K. Although bulk superconductivity is confirmed in La3Co, as observed previously, only a trace of it is found in La3Ni, indicating that the...
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Radio Channel Measurements in Body-to-Body Communications in Different Scenarios
PublikacjaThis paper presents body-to-body radio channel measurements at the 2.45 GHz band, for different body motion scenarios and on-body antenna placements, and both indoor and outdoor environments. Measurement equipment, investigated scenarios and considered environments are described, an initial analysis of results being presented. The mean path loss and the standard deviation depend on the mutual location of transmitting and receiving...
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Phage-Directed Synthesis of Photoluminescent Zinc Oxide Nanoparticles under Benign Conditions
PublikacjaBiological systems, especially bacteriophages and peptides, are an attractive green alternative to other known methods of nanoparticle synthesis. In this work, for the first time, bacteriophages were employed to synthesize a specific peptide, capable of producing nanoparticles (NPs). Derivatives of M13 bacteriophage exposing a ZnO-binding peptide (TMGA-LGLKWPV) on either pIII or pVIII phage coat protein were constructed and used...
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A concept of Signal Equalization Method Based on Music Genre and the Listener's Room Characteristics
PublikacjaA research study that investigates the influence of the room acoustics environment on the frequency characteristic of the audio signal playback is presented. First, a novel spectral equalization method of the room acoustic conditions is introduced. On the basis of the frequency response of the room, a system for room acoustics compensation based on eight-band equalizer is proposed. The system settings depend on music genre. In...
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Detection and Direction-of-Arrival Estimation of Weak Spread Spectrum Signals Received with Antenna Array
PublikacjaThis paper presents a method for the joint detection and direction of arrival (DOA) estimation of low probability of detection (LPD) signals. The proposed approach is based on using the antenna array to receive spread-spectrum signals hidden below the noise floor. Array processing exploits the spatial correlation between phase-delayed copies of the signal and allows us to evaluate the parameter used to make the decision about the...
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Kriging metamodels and design re‐utilization for fast parameter tuning of antenna structures
PublikacjaThe paper addresses the problem of computationally efficient electromagnetic (EM)‐driven design closure of antenna structures. The foundations of the presented approach are fast kriging interpolation metamodels, utilized for two purposes: (a) producing a good starting point for further parameter tuning, and (b) yielding a reasonable Jacobian matrix estimate to jump‐start the optimization procedure. The models are rendered using...
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Planar Microwave Bragg Reflector Resonant Dielectric Sensor
PublikacjaIn this paper, a periodic structure is used to design a microwave Bragg reflector with the help of hexagonal lattice, which provides a 5 GHz wide stopband between the low-pass band with cut-off frequency 2.6 GHz and the bandpass response with start and stop frequency 7.8 GHz and 10.5 GHz, respectively. A defect in lattice allows passing a narrowband signal at 6 GHz which is found, from the dispersion relation, to be in the region...
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On the Consumption of Multimedia Content Using Mobile Devices: a Year to Year User Case Study
PublikacjaIn the early days, consumption of multimedia content related with audio signals was only possible in a stationary manner. The music player was located at home, with a necessary physical drive. An alternative way for an individual was to attend a live performance at a concert hall or host a private concert at home. To sum up, audio-visual effects were only reserved for a narrow group of recipients. Today, thanks to portable players,...
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Free-standing TiO2 nanotubes decorated with spherical nickel nanoparticles as a cost-efficient electrocatalyst for oxygen evolution reaction
PublikacjaHere, we report significant activity towards the oxygen evolution reaction (OER) of spherical nickel nanoparticles (NPs) electrodeposited onto free-standing TiO2 nanotubes (TNT) via cyclic voltammetry. It has been shown that simple manipulation of processing parameters, including scan rate and number of cycles, allows for formation of the NPs in various diameters and amounts. The polarization data with respect to transmission electron...
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Numerical analyses of novel prefabricated structural wall panels in residential buildings based on laboratory tests in scale 1:1
PublikacjaThe paper presents experimental and numerical investigations on novel prefabricated composite building wall panels for residential building constructions. The wall panels were composed of reinforced concrete ribbed elements with the core from the EPS foam as the thermal insulation. The wall panels in the full-scale 1:1 were subjected to vertical loads. In the first step, the experiments were analysed with simple usual static methods....
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Triangulation-based Constrained Surrogate Modeling of Antennas
PublikacjaDesign of contemporary antenna structures is heavily based on full-wave electromagnetic (EM) simulation tools. They provide accuracy but are CPU-intensive. Reduction of EM-driven design procedure cost can be achieved by using fast replacement models (surrogates). Unfortunately, standard modeling techniques are unable to ensure sufficient predictive power for real-world antenna structures (multiple parameters, wide parameter ranges,...
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Modification of Titanium (IV) Dioxide with Small Silver Nanoparticles: Application in Photocatalysis
PublikacjaThe surface of commercial TiO2 compounds (P25 and ST01) has been modified with Ag nanoparticles induced by radiolysis. On P25, the Ag nanoclusters are very small (1−2 nm) and homogeneous in size while on ST01, two populations of nanoparticles are obtained, small nanoparticles (1−2 nm) and larger ones (mean diameter 7 to 12 nm depending on the silver loading). The photocatalytic properties of Ag-modified TiO2 have been studied for...
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A Geometrically Simple Compact Wideband Circularly Polarized Antenna
PublikacjaA compact broadband wide-slot circular polarization (CP) antenna is proposed. An inverted L-shape parasitic strip at the open end of a microstrip line extension and a slot modification is applied to attain wideband CP. The advantage of this technique is simplicity which makes it readily re-designable for different frequency bands. To demonstrate the concept, three designs working at different frequencies are obtained. The redesign...
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Influence of orientational disorder on the optical absorption properties in hybrid metal‐halide perovskite CH3NH3PbI3. A combined DFT/TD‐DFT and experimental study.
PublikacjaAn experimental and theoretical investigation is reported to analyze the relation between the structural and absorption properties of CH3NH3PbI3 in the tetragonal phase. More than 3000 geometry optimizations were performed in order to reveal the structural disorder and to identify structures with the lowest energies. The electronic structure calculations provide an averaged band gap of 1.674 eV, which is in excellent agreement...
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Enhanced photocatalytic properties of lanthanide-TiO2 nanotubes: An experimental and theoretical study
PublikacjaA series of Er-, Yb-, Ho-, Tb-, Gd-, Pr-TiO2 nanotubes (RE-NTs) was prepared via an electrochemical method. The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–vis absorption, scanning electron microscopy (SEM) and luminescent spectroscopy. The experiments demonstrated that toluene in the gas phase was successfully degraded under visible light (LEDs λmax = 465...
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The potential of imogolite nanotubes as (co-)photocatalysts: a linear-scaling density functional theory study
PublikacjaWe report a linear-scaling density functional theory (DFT) study of the structure, wall-polarization absolute band-alignment and optical absorption of several, recently synthesized, open-ended imogolite (Imo) nanotubes (NTs), namely single-walled (SW) aluminosilicate (AlSi), SW aluminogermanate (AlGe), SW methylated aluminosilicate (AlSi-Me), and double-walled (DW) AlGe NTs. Simulations with three different semi-local and dispersion-corrected...
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Independent dynamics of slow, intermediate, and fast intracranial EEG spectral activities during human memory formation
PublikacjaA wide spectrum of brain rhythms are engaged throughout the human cortex in cognitive functions. How the rhythms of various low and high frequencies are spatiotemporally coordinated across the human brain during memory processing is inconclusive. They can either be coordinated together across a wide range of the frequency spectrum or induced in specific bands. We used a large dataset of human intracranial electroencephalography...
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Effect of nitrogen doping on TiOxNy thin film formation at reactive high-power pulsed magnetron sputtering
PublikacjaThe paper is focused on a study of formation of TiOxNy thin films prepared by pulsed magnetron sputtering of metallic Ti target. Oxygen and nitrogen were delivered into the discharge in the form of reactive gases O2 and N2. The films were deposited by high-power impulse magnetron sputtering working with discharge repetition frequency f = 250 Hz at low (p = 0.75 Pa) and high (p = 10 Pa) pressure. The substrates were on floating...
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Copper(II) complexes with substituted imidazole and chlorido ligands: X-ray, UV-Vis, magnetic and EPR studies and chemotherapeutic potential
PublikacjaCrystal structures, UV-Vis and EPR spectra and magnetic properties of four copper(II) complexes with chloride anions and 4-methylimidazole, 2-ethylimidazole, 2-isopropylimidazole or 2-ethyl-4-methylimidazole are described. In the solid state three of the complexes are mononuclear and one complex with 2-ethylimidazole is binuclear with bridging chlorido ions. UV-Vis spectra of the methanolic solutions of the complexes show LMCT...
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Spectacular Oxygen Evolution Reaction Enhancement Through Laser Processing of the Nickel-Decorated Titania Nanotubes
PublikacjaThe selective, laser-induced modification of the nickel-decorated titania nanotubes provides remarkable enhancement toward oxygen evolution reaction. Particularly, the irradiation of the laterally spaced crystalline TiO2 nanotubes, results in the formation of the tight closure over irradiated end, preserving their hollow interior. The shape of the absorbance spectra is modulated along with applied energy, and the new absorption...
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Experimental tuning of AuAg nanoalloy plasmon resonances assisted by machine learning method
PublikacjaPlasmonic nanostructures based on AuAg nanoalloys were fabricated by thermal annealing of metallic films in an argon atmosphere. The nanoalloys were chosen because they can extend the wavelength range in which plasmon resonance occurs and thus allow the design of plasmonic platforms with the desired parameters. The influence of initial fabrication parameters and experimental conditions on the formation of nanostructures was investigated....
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Low-Voltage Low-Power Filters with Independent ω0 and Q Tuning for Electronic Cochlea Applications
PublikacjaAn acoustic second-order low-pass filter is proposed for filter banks emulating the operation of a human cochlea. By using a special filter structure and an innovative quality (Q)-factor tuning technique, an independent change of the cutoff frequency (ω0) and the Q-factor with unchanged gain at low frequencies is achieved in this filter. The techniques applied result in a simple filter design with low Q-factor sensitivity to component...
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Spectacular Oxygen Evolution Reaction Enhancement through Laser Processing of the Nickel‐Decorated Titania Nanotubes
PublikacjaThe selective, laser‐induced modification of the nickel‐decorated titania nanotubes provides remarkable enhancement toward oxygen evolution reaction. Particularly, the irradiation of the laterally spaced crystalline TiO2 nanotubes, results in the formation of the tight closure over irradiated end, preserving their hollow interior. The shape of the absorbance spectra is modulated along with applied energy, and the new absorption...
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Simple 60 GHz Switched Beam Antenna for 5G Millimeter-Wave Applications
PublikacjaA new 60 GHz band single-input switched beam antenna is proposed for the fifth-generation (5G) millimeter-wave network applications. The presented design is capable of electronically switching the main beam in two different directions via a proposed microstrip-line-to-slotline single-pole dual-throw (SPDT) switch based on commercially available p-i-n diodes. The antenna is fabricated in a low-cost printed circuit board process...
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Utilization of oriented crystal growth for screening of aromatic carboxylic acids cocrystallization with urea
PublikacjaThe possibility of molecular complex formation in the solid state of urea with benzoic acid analogues was measured directly on the crystallite films deposited on the glass surface using powder X-ray diffractometry (PXRD). Obtained solid mixtures were also analyzed using Fourier transform infrared spectroscopy (FTIR). The simple droplet evaporation method was found to be efficient, robust, fast and cost-preserving approach for first...
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Size reduction of ultra-wideband antennas with efficiency and matching constraints
PublikacjaAntenna design is a multifaceted task that involves handling of various performance figures concerning both electrical performance of the structure as well as its geometry. Simultaneous control of several objectives through rigorous optimization is very challenging and virtually impossible through conventional approaches such as parameter sweeping. In this work, we investigate size reduction of ultra‐wideband antenna structures...
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A Novel Ru(II) Polypyridine Black Dye Investigated by Resonance Raman Spectroscopy and TDDFT Calculations
PublikacjaThe optical properties of a new(bipyridine)2Ru(4H-imidazole) complex presenting a remarkablebroad absorption in the visible range are investigated. Thestrong overlap of the absorption with the solar radiationspectrum renders the studied complex promising as a blackabsorber and hence as a starting structure for applications inthe field of dye-sensitized solar cells. The correlations betweenstructural and electronic features for...
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Structural and physical characterization of NpPt2In7
PublikacjaA new neptunium intermetallic compound, NpPt2In7, has been synthesized in polycrystalline form and characterized by several macroscopic techniques. A Rietveld analysis of its powder x-ray diffraction pattern shows that NpPt2In7 crystallizes in a tetragonal lattice with I4/mmm symmetry and lattice parameters a = 4.58471(3) Å, c = 21.5065(3) Å. Magnetic susceptibility, electrical resistivity, Hall effect, and heat capacity measurements indicate...
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Fast EM-Driven Nature-Inspired Optimization of Antenna Input Characteristics Using Response Features and Variable-Resolution Simulation Models
PublikacjaUtilization of optimization technique is a must in the design of contemporary antenna systems. Often, global search methods are necessary, which are associated with high computational costs when conducted at the level of full-wave electromagnetic (EM) models. In this study, we introduce an innovative method for globally optimizing reflection responses of multi-band antennas. Our approach uses surrogates constructed based on response...
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Rapid multi-criterial design of microwave components with robustness analysis by means of knowledge-based surrogates
PublikacjaManufacturing tolerances and uncertainties concerning material parameters, e.g., operating conditions or substrate permittivity are detrimental to characteristics of microwave components. The knowledge of relations between acceptable parameter deviations (not leading to violation of design specifications) and the nominal performance (not considering uncertainties), and is therefore indispensable. This paper proposes a multi-objective...