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Search results for: PHASE CHANGE MATERIAL
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On the importance of volume of eroded material for cavitation erosion
PublicationW pracy przedstawiono model matematyczny opisujący wpływ objętości erodowanego materiału na przebieg krzywych erozji kawitacyjnej
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Preparation of samples of plant material for chromatographic analysis
PublicationPrzedstawiono informacje literaturowe nt. etapów przygotowania próbek materiału roślinnego do analizy chromatograficznej. Szczególną uwagę zwrócono na techniki izolacji i/lub wzbogacenie analitów przed etapem oznaczeń końcowych, walidację stosowanych procedur, sposoby pobierania próbek celem określenia emisji biogenicznej lotnych związków organicznych.
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On a 3D material modelling of smart nanocomposite structures
PublicationSmart composites (SCs) are utilized in electro-mechanical systems such as actuators and energy harvesters. Typically, thin-walled components such as beams, plates, and shells are employed as structural elements to achieve the mechanical behavior desired in these composites. SCs exhibit various advanced properties, ranging from lower order phenomena like piezoelectricity and piezomagneticity, to higher order effects including flexoelectricity...
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Monitoring of Rubber Belt Material Performance and Damage
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Impedance evaluation of coatings from biobased material
PublicationThe authors propose a modification of sodium caseinate edible coating for foodstuff protection. The aim was to improve the film’s barrier properties. It was achieved by the addition of propolis, which is a natural, environmentally friendly product known from its intrinsic sealing action. In the next step, propolis-admixed sodium caseinate films were exposed to elevated temperature for 10 min. This approach was meant to improve...
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Phase separation in poly(butylene terephthalate)-based materials prepared by solid-state modification
PublicationThe morphology of a series of poly(butylene terephthalate) (PBT)/fatty acid dimer diol (FADD)-based copolyesters prepared by solid-state modi fi cation (SSM) was studied. It was shown that in copolyesters containing less than 10 wt% FADD two different phases, i.e. a PBT crystalline phase and a PBT-rich amorphous phase, are present. The FADD residues were more or less homogeneously distributed throughout the interlamellar regions....
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Carbon Nanomaterials From Metal-Organic Frameworks: A New Material Horizon for CO2 Reduction
PublicationThe rise of CO2 in the atmosphere, which results in severe climate change and temperature increase, is known as the major reason for greenhouse effect. Reducing CO2 to value-added products is an attractive solution to this severe problem, along with addressing the energy crisis, to which the catalysts being employed are of vital importance. Due to their high porosity and tunable compositions, Metal-Organic Frameworks (MOFs) show...
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Blowing Kinetics, Pressure Resistance, Thermal Stability, and Relaxation of the Amorphous Phase of the PET Container in the SBM Process with Hot and Cold Mold. Part II: Statistical Analysis and Interpretation of Tests
PublicationThe technology of filling drinks without preservatives (such as fresh juices, iced tea drinks, and vitaminized drinks) is carried out using hot filling. Mainly due to the production costs and lower carbon footprint, polyethylene terephthalate (PET) bottles are increasingly used in this technology. In this paper, the main aim is to describe and interpret the results of statistical analysis of the influence of the temperature of...
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Membranowe przekrycia wiszące -zagadnienia konstrukcyjno-materiałowe. Membrane hanging roof - constructional-material problems.
PublicationArtykuł przedstawia przykłady zastosowania membranowych przekryć wiszących w budownictwie ogólnym. Dodatkowo zwraca uwagę na wybrane zagadnienia konstrukcyjno-materiałowe tego typu obiektów.This paper presents the application examples of membrane hanging roof in building engineering. Additionally, attention to the chosen constructional-material problems of this type of structures has been focused.
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One Year Evaluation of Material Properties Changes of Polylactide Parts in Various Hydrolytic Degradation Conditions
PublicationBiodegradable biocompatible materials are widely used in medical applications. Determining the possibility of using biodegradable materials depends on determining the changes in their parameters over time due to degradation. The current scientific research on biodegradable materials has presented results based on research methods characterized by the different geometry and cross-section size of the specimen, type of degradation...
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Dead-Time Effect Compensation Based on Additional Phase Current Measurements
PublicationThis paper proposes a new method of dead-time effect compensation. The proposed solution is based on additional phase current measurements realized by analog-to-digital converters. These measurements are carried out at the time instants specified by a pulsewidth-modulation (PWM) strategy. This makes it possible to estimate inverter currents at the commutation instants and, finally, to estimate the voltage error caused by dead time. This...
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DIFFRACTION PHASE MICROSCOPY FOR OBSERVATION ON RED BLOOD CELLS FLUCTUATION
PublicationNowadays there is quite huge need for more and more precise and effective fast diagnostics methods in hematology diseases. One of the most important blood components are erythrocytes – RBCs (Red Blood Cells). Due to their size they are easy to observe using microscopy. It is commonly known that the shape and lifetime of RBCs allows for early disease identification. Authors present special measurement system for RBCs fluctuations observation...
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Study of Phase and Chemical Composition of Bi1-xNdxFeO3 Powders Derived by Pressureless Sintering
PublicationIn the present paper studies on Bi1xNdxFeO3 for x =0.1-0.4 are reported. The mixed oxide method followed with pressureless sintering was employed for ceramics fabrication. Thermal behavior of stoichiometric mixtures of simple oxide powders, viz. Bi2O3, Nd2O3 and Fe2O3 was studied by simultaneous thermal analysis. It was found that with an increase in neodymium content the weight loss increased from 0.75% to 3.16% for x =0.1 and...
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FE analysis of a coupled energetic-statistical size effect in plain concrete beams with varying material properties.
PublicationThe numerical FE investigations of a coupled energetic-statistical size effect in unnotched concrete beams of similar geometry under quasi-static three point bending were performed within elasto-plasticity with non-local softening. The stochastic FE analyses were carried out with three different beam sizes. Deterministic calculations were performed with the uniform distribution of a uniaxial tensile strength. In statistical calculations...
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Rapid redesign of multiband antennas with respect to operating conditions and material parameters of substrate
PublicationThis work addresses geometry parameter scaling of multi-band antennas for Internet of Things applications. The presented approach is comprehensive and permits re-design of the structure with respect to both the operating frequencies and material parameters of the dielectric substrate. A two-step procedure is developed with the initial design obtained from an inverse surrogate model constructed using a set of appropriately prepared...
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Carbon dioxide ocean and ground storage as a method of climate change mitigation
PublicationW pracy dokonano krytycznego przeglądu negatywnego wpływu globalnego ocieplenia na środowisko i przedstawiono dwie nowatorskie metody zmniejszenia stężenia atmosferycznego ditlenku węgla. Obie metody: magazynowanie antropogenicznego ditlenku węgla, pochodzącego z dużych źródeł emisji, w oceanach i w glebie są technologicznie możliwe do przeprowadzenia, co potwierdzają przykłady z różnych regionów świata. W pracy przedyskutowano...
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How insignificant modifications of photocatalysts can significantly change their photocatalytic activity
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Analysis of the torque response of a car engine to the step change of the control signal
PublicationW pracy zamieszczono wyniki badań silnika samochodu osobowego w warunkach nieustalonych. Stan obciążenia silnika wynikał z realizowanego cyklu jezdnego w warunkach drogowych oraz sposobu sterowania układem napędowym. Parametry trakcyjne pojazdu mierzone były za pomocą systemu GPS z fenomenologiczną korektą sygnału wysokości, na której się on znajdował. Wybrane parametry pracy silnika mierzone były za pomocą sytemu komunikującego...
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Tendencies of change in the chemistry of precipitation at three monitoring stations 1996-1999.
PublicationW pracy przedstawiono wyniki porównawczych badań składu próbek opadów deszczowych zebranych na trzech stacjach w okresie 1996-1999, (stacje te różnią się zdecydowanie ze względu na usytuowanie geograficzne). W postaci graficznej przedstawiono zaobserwowane tendencje w składzie zebranych próbek wód opadowych.
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The effect of the temperature change rate on determination of the criticalpitting temperature of stainless steels
PublicationPrzedstawiono wyniki badań wpływu szybkości zmian temperatury na wyznaczaną krytyczną temperaturę korozji wżerowej. Badania stali 316L przeprowadzono metodą termometrii cyklicznej. Stwierdzono, że zwiększenie szybkości zmian temperatury związane jest ze zwiększeniem wyznaczonej temperatury krytycznej. Zależność krytycznej temperatury korozji wżerowej od szybkości korozji ma charakter liniowy. Wartości krytycznej temperatury korozji...
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Tropospheric thermal field variability over Poland in the context of climate change
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Numerical single-phase modeling of turbulent flow and heat transfer of nanofluids
PublicationIn this work, Nusselt number and friction factor are calculated numerically for turbulent pipe flow (6 000< Re < 12 000) with constant heat flux boundary condition using nanofluids. The nanofluid is modelled with the single-phase approach and the simulation results are compared with published experimental data.
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Single-phase power electronics transformer with active functions for smart grid
PublicationThis paper presents the control of one cell of a modular single-phase power electronics transformer with active functions for meeting the smart grid concept. In this way, the converter could be used not only as a conventional transformer but also for grid such as reactive power, harmonic elimination and energy storage. The topology of the cell is composed by a bidirectional converter with three stages: a half bridge in the input...
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Numerical Analysis of Mice Carotid Arteries’ Response Emphasizing the Importance of Material Law Constants’ Validation
PublicationIn this paper, a detailed validation of the passive material properties of mice carotid arteries and constants of the Fung and Holzapfel hyperelastic material laws is conducted by means of static nonlinear FEM analyses. The response of the carotid arteries in an inflation test is studied here for the following mouse models: wild-type, mdx, sgcd−/−, Eln+/+, Eln+/−, Fbln5+/+, and Fbln5−/−. All FEM computations are conducted on models...
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Evaluation of candidate reference material obtained from selenium - enriched sprouts for the purpose of selenium speciation analysis
PublicationSelenium is an essential element in animals and humans. Diet supplementation with selenium-rich vegetables has better chemoprotective effect than Se (IV) and SeMet. The production of selenium-enriched vegetables requires a preliminary stage in soil preparation, which may subsequently pose a risk of soil contamination. It seems that the sprouting of seeds under controlled conditions would be a good solution for delivering SeMetSeCys...
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Determination of leakage inductances of multi-winding and single-phase transformer
PublicationThis paper presents the method for determination of leakage inductances of single-phase and multi-winding transformer. The matrix of leakage inductances takes into account leakage self and also leakage mutual magnetic couplings. It is assumed that there is a flux common to all windings and several leakage fluxes referred to a particular winding. The flux linkages of each coil needed fo calculation of leakage inductances was computed...
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Two-phase flow in heterogeneous porous media with non-wetting phase trapping
PublicationThis article presents amathematical model describing flowof two fluid phases in a heterogeneous porous medium. Zaproponowano model matematyczny przepływu dwufazowego w drobnoziarnistym ośrodku porowatym zawierającym inkluzje gruboziarniste. Inkluzje charakteryzują się niższą wartością ciśnienia wejścia dla płynu niezwilżającego (np. powietrze, ropa naftowa) niż materiał podstawowy. Podczas nawadniania takiego ośrodka dochodzi do...
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A comprehensive evaluation of flexible FDM/FFF 3D printing filament as a potential material in medical application
PublicationThe use of FDM/FFF in 3D printing for medical sciences is becoming common. This is due to the high availability and decent price of both 3D printers and filaments useful for FDM/FFF. Currently, researchers' attention is focused mainly on the study of medical filaments based on PLA, PCL or their modifications. This contributes to insufficient diversity of medical-grade filaments on the market. Moreover, due to the lack of specified...
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Sensorless Disturbance Detection for Five Phase Induction Motor with Third Harmonic Injection
PublicationThe paper presents a sensorless disturbance detection procedure that was done on a five phase induction motor with third harmonic injection. A test bench was developed where a three phase machine serves as disturbance generator of different frequencies. The control of the machines is based on multi scalar variables that ensures an independent control of the motor EMF and the rotor flux. For disturbance identification a speed observer...
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Numerical Simulations of Seepage in Dikes Using unsaturated and Two-Phase Flow Models
PublicationModeling of water flow in variably saturated porous media, including flood dikes, is often based on the Richards equation, which neglects the flow of pore air, assuming that it remains at constant atmospheric pressure. However, there is also evidence that the air flow can be important, especially when the connectivity between the pore air and atmospheric air is lost. In such cases a full two-phase air-water flow model should be...
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Radar Signal Parameters Estimation Using Phase Accelerogram in the Time-Frequency Domain
PublicationRadar signal parameter estimation, in the context of the reconstruction of the received signal in a passive radar utilizing other radars as a source of illumination, is one of the fundamental steps in the signal processing chain in such a device. The task is also a crucial one in electronic reconnaissance systems, e.g. ELINT (Electronic Intelligence) systems. In order to obtain accurate results it is important to measure, estimate...
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Observation on red blood cells fluctuations by diffraction phase microscopy
PublicationNowadays there is quite huge need for more and more precise and effective fast diagnostics methods in hematology diseases. One of the most important blood components are erythrocytes – Red Blood Cells (RBCs). Due to their size they are easy to observe using microscopy. It is commonly known that the shape and lifetime of RBCs allows for early disease identification. Authors present special measurement system for RBCs fluctuations...
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Improvements to the two-phase sandwich method for calculating the melting points of pure metals
PublicationThe thermophysical properties of metal alloys are often investigated via molecular dynamics (MD) simulations.An exact and reliable estimation of the thermophysical parameters from the MD data requires a properly and carefullyelaborated methodology. In this paper, an improved two-phase sandwich method for the determination of the metal meltingtemperature is proposed, based on the solid-liquid equilibrium theory. The new method was...
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Five-phase squirrel-cage motor. Construction and drive properties
PublicationThis paper presents the simulation and experimental results of a five-phase squirrel-cage induction motor. The new machine has been designed to operate in a drive system with third harmonic rotor flux injection in order to improve the motor torque utilization. The motor structure, the mathematical model as well as the laboratory prototype have been described. The motor speed-torque characteristics and transients are elaborated...
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Comparison of Transmission Capacities of Two Regulation Systems: Lateral and in-phase Control Transformers
PublicationThis paper presents a comparison of regulation capabilities of lateral and in-phase control transformers in a selected node of a power system. Their regulation capabilities are presented, as well as cross-system exchange options.
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3-phase medium frequency transformer for a 100kW 1.2kV 20kHz Dual Active Bridge converter
PublicationThe article presents a three-phase Medium Frequency Transformer being a part of a 100kW 1.2kV 20kHz Dual Active Bridge DC-DC converter. The transformer design is detailed focusing on winding and core power loss calculation. The high power three-phase MFT prototype is presented. The experimental results include the transformer impedance characteristics, no load test and three-phase DAB full load test waveforms
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Solid Phase Synthesis and Biological Activity of Tuftsin Conjugates
PublicationNew tuftsin/retro-tuftsin conjugates were designed and synthesized using a classical fluorenylmethoxycarbonyl (Fmoc) solid phase procedure. All the peptide conjugates were divided into three series: 1,4-dihydroxyanthraquinone (type A), 1-nitroacridine (type B), and 4-carboxyacridone (type C) derivatives. In type A conjugates, the N-terminal group of the peptide chain is directly connected to the anthraquinone ring at C1 (Scheme...
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The Influence of Drying Temperature on Color Change of Hornbeam and Maple Wood Used as Surface and Inner Layers of Wood Composites
PublicationThe thermal treatment of wood changes its structure due to the degradation of wood polymers (cellulose, hemicellulose and lignin), so the physical properties of wood are either improved or degraded. Color changes apply not only to natural wood, but also to such wood composites for which some amount of glue is used in their construction (e.g., plywood, blockboard or laminboard). This article is focused on the analysis of hornbeam...
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Improving the Performance of a Graphite Foil/Polyaniline Electrode Material by a Thin PEDOT:PSS Layer for Application in Flexible, High Power Supercapacitors
PublicationIn this study, we present a novel strategy for enhancing polyaniline stability and thus obtaining an electrode material with practical application in supercapacitors. A promising (graphite foil/polyaniline/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) GF/PANI/PEDOT:PSS) electrode material was characterized and used in the construction of a symmetric supercapacitor that provides an outstanding high power density. For this...
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Solventless sample preparation techniques based on solid- and vapour-phase extraction
PublicationThe main objective of this review is to critically evaluate recent developments in solventless sample preparation techniques. The potential of a variety of sample preparation techniques based on solid- and vapour-phase extraction techniques is evaluated. Direct thermal extraction and derivatization processes to facilitate the extraction of analytes in different areas are included. The applicability, disadvantages and advantages...
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Sensorless Multiscalar Control of Five-Phase Induction Machine with Inverter Output Filter
PublicationThe paper presents a complete solution for speed sensorless control system for five-phase induction motor with voltage inverter, LC filter and nonlinear control of combined fundamental and third harmonic flux distribution. The control principle, also known as multiscalar control, nonlinear control or natural variables control, is based on a use of properly selected scalar variables in control feedback to linearize controlled system....
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Size Exclusion Coupled to Reversed Phase Liquid Chromatography for the Characterization of Cranberry Products
PublicationA combination of solvent extraction, size exclusion purification, and reversed-phase liquid chromatography with UV absorption and fluorescence detection was here used for the determination of flavan-3-ols and related oligomeric compounds in cranberry products. The method relied on robust, simple, and inexpensive instrumental equipment present in most of routine analytical laboratories. Sample extracts in methanol/water/hydrochloric...
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Structural Adaptive, Self-Separating Material for Removing Ibuprofen from Waters and Sewage
Publication-cyclodextrin nanosponge (CDM) was used for the adsorption of ibuprofen (IBU) from water and sewage. The obtained material was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET), Barrett– Joyner–Halenda (BJH), Harkins and Jura t-Plot, zeta potential, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and elementary analysis (EA)....
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Studies on the Presence and Spatial Distribution of Anthropogenic Pollution in the Glacial Basin of Scott Glacier in the Face of Climate Change (Fiord Bellsund, Spitsbergen)
PublicationThe study area covered the NW part of the Wedel Jarlsberg Land (SW part of the Svalbard Archipelago). The primary study object was the catchment of the Scott Glacier in the vicinity of the Research Station of of Maria Curie-Skłodowska University in Lublin – Calypsobyen. The Scott River catchment (of glacial hydrological regime) has an area of approximately 10 km2, 40% of which is occupied by the valley Scott Glacier in the phase...
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Compact 4 × 4 butler matrix with non‐standard phase differences for IoT applications
PublicationButler matrices represent a popular class of feeding networks for antenna arrays. Large dimensions and the lack of flexibility in terms of achievable output phase difference make conventional Butler structures of limited use for modern communication devices. In this work, a compact planar 4 × 4 matrix with non-standard relative phase shifts of –30º, 150º, –120º, and 60º has been proposed. The structure is designed to operate at...
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Solid phase microextraction: state of the art, opportunities and applications
PublicationSolid phase microextraction is one of the most popular green techniques used for sample preparations in analytical chemistry. It is a simple, rapid, sensitive, and solvent-free technique. Since SPME was first introduced in the early 1990s, there has been an intensification of research in order to elaborate new methodical solutions in many research facilities around the world, which could increase the use of this technique. More...
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Measurement method for capacitive sensors for microcontrollers based on a phase shifter
PublicationA complete measurement method dedicated to capacitive sensors has been developed. It includes the development of hardware (an analogue interface circuit for microcontrollers with built-in times/counters and analogue comparators) and software (a measurement procedure and a systematic error calibration (correction) algorithm which is based on a calibration dictionary). The interface circuit consists of a low-pass filter and a phase...
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Nano Tin/Tin Oxide Attached onto Graphene Oxide Skeleton as a Fluorine Free Anode Material for Lithium-Ion Batteries
PublicationHerein, we show a composite formation method of tin/tin oxide nanoparticles with graphene oxide and CMC based on laser ablation technique as an electrode material for energy storage devices. The material exhibited a three-dimensional conducting graphene oxide network decorated with tin or tin oxide nanoparticles. The structure, homogeneous distribution of nanoparticles, and direct contact between inorganic and organic parts were...
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A Linear Phase Filter in Quadruplet Topology With Frequency-Dependent Couplings
PublicationThis letter presents a design of a linear phase microwave bandpass filter. The filter is composed of four resonators arranged in the quadruplet topology. Making the cross and one direct coupling dispersive gives additional design flexibility. The first advantage of using frequency-dependent couplings is the possibility to chose an arbitrary location of a pair of complex transmission zeros (TZs) in the s-domain. The second one is...
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Modern trends in solid phase extraction: New sorbent media
PublicationBased on the recently published literature, this review provides an update of the most important features and application of formats and devices employed in solid phase extraction (SPE). Special attention was paid on new trapping media proposed in SPE prior the chromatography analysis, based on the use of nanostructured materials, including carbon nanomaterials, electrospun nanofibers, dendrimes and magnetic nanoparticles, molecular...