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Wyniki wyszukiwania dla: PHASE-TRANSITIO
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Solid-Phase Microextraction for the Determination of Inorganic Ions: Applications and Possibilities
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Porous, High Capacity Coatings for Solid Phase Microextraction by Sputtering
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Rich magnetic phase diagram in the Kagome-staircase compound Mn3V2O8
PublikacjaNa podstawie pomiarów podatności magnetycznej i ciepła właściwego monokryształu Mn3V2O8 skonstruowano diagram fazowy. Właściwości magnetyczne związku są silnie anizotropowe.
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Ifluence of geometrical and thermophysical parameters on two-phase thermosiphon performance
PublikacjaW pracy przedstawiono wyniki badań eksperymentalnych dotyczących wpływu geometrii pęku rur, rodzaju powierzni przejmowania ciepła parownika oraz płynu pośredniego na całkowitą wydajność dwufazowego termosyfonowego wymiennika ciepła (DTWC).
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Heat transfer characteristics of a two-phase thermosyphon heat exchanger
PublikacjaPrzedstawiono wyniki badań wpływu geometrii parownika, rodzaju rur użytych do budowy parownika, rodzaju cieczy pośredniej oraz poziomu cieczy nad najwyższym rzędem rur na działanie dwufazowego, termosyfonowego wymiennika ciepła. Zaprezentowano algorytm obliczeń przedstawionego wymiennika.
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Determination of leakage inductances of multi-winding and single-phase transformer
PublikacjaThis 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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Strong-coupling character of superconducting phase in compressed selenium hydride
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Cooperation of a Non-Linear Receiver with a Three-Phase Power Grid
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Five-phase induction motor drive with sine-wave filter
PublikacjaThe paper presents closed loop ac drive with 5 phase induction motor operating with voltage source inverter and sine wave filter. The motor supply voltages and currents have sinusoidal shape. For well known adjustable electric drives the field oriented control method with flux and speed co ntrol can be applied. In the presence of output filter both control and estimation algorithms should be modified due to sine wave filter installation....
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Representation of magnetic hysteresis in single-phase transformer for circuit simulations
PublikacjaThe paper presents a mathematical model for the hysteresis phenomenon in a multi-winding single-phase core type transformer. In the circuit transformer model, it is assumed that there is a flux common Φ to all windings as nonlinear and hysteretic function of the total currents Θ (Ampere turns) of all windings. To simulate magnetic behaviour of the iron core the feedback scalar Preisach model of hysteresis is developed. The Preisach...
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Membrane Solid Phase Microextraction - a new concept of sorbent preparation
PublikacjaOpracowano nowy układ sorpcyjny do izolacji i/lub wzbogacania polarnych analitów organicznych z próbek wody z zastosowaniem techniki solid phase microextraction (SPME). Układ bazuje na oddzieleniu sorbentu polarnego od próbki za pomocą membrany hydrofobowej. Próbnik membrane-SPME (M-SPME) sporządzono z zastosowaniem polietylenoglikolu (PEG)o masie cząsteczkowej 20 kDa. Polimer ten jest rozpuszczalny w wodzie i w typowych warunkach...
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Five-Phase EV Drive with Switched-Autotransformer (LCCAt) Inverter
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Observation on red blood cells fluctuations by diffraction phase microscopy
PublikacjaNowadays 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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A Linear Phase Filter in Quadruplet Topology With Frequency-Dependent Couplings
PublikacjaThis 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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Low-energy positron scattering from gas-phase uracil
PublikacjaQuantum scattering calculations are presented for the interaction of low energy positrons with the uracil molecule, an important component of biological systems. The rotational elastic and inelastic cross sections and vibrational inelastic cross sections are reported and compared with existing experiments, indicating a general trend of the cross sections different from the experimental findings and in line with what should be expected...
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Hydration phase diagram for sodium cobalt oxide NaxCoO2*yH2O
PublikacjaPrzedstawiony został diagram fazowy uwodnionego, sodowo kobaltowego związku tlenkowego Na0.3CoO2*yH2O. Diagram powstał w oparciu o zależność stopnia uwodnienia (y) od wilgotności względnej w temperaturze pokojowej. Zaobserwowano trzy fazy: y = 0, 0.6 i 0.13. Zauważono histerezę przy zamianie kierunku procesu uwadniania.
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Convective momentum and heat transfer in single and two-phase flows
PublikacjaW pracy przedstawiono dorobek autora w zakresie modeowania wymiany pędu i ciepław w przepływach jedno i dwufazowych.
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Hydration phase diagram for sodium cobalt oxide Na0.3CoO2·yH2O
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Representation of magnetic hysteresis in a circuit model of a single-phase transformer
PublikacjaThe paper presents a mathematical model for the hysteresis phenomenon in a multi-winding single-phase core type transformer. The set of loop differential equations was developed for K-th winding transformer model where the flux linkages of each winding includes a flux common Φ to all windings as function of magneto motive force Θ of all windings. The first purpose of this paper is to determine a hysteresis nonlinearity involved...
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A study on application of Smoothed Particle Hydrodynamics to multi-phase flows
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A study on application of Smoothed Particle Hydrodynamics to multi-phase flows
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Accuracy of Differential Phase Delay Estimation for GPS Spoofing Detection
PublikacjaGPS spoofing is an attack based on transmission of false signals to target receivers, in order to force the computation of incorrect time, position or velocity information. It is a threat which is recently considered with continuously growing awareness. There is a need for effective way of GPS spoofing detection. Many groups of methods are proposed in the literature. Spatial processing methods are considered to be robust in a wide...
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Green aspects, developments and perspectives of liquid phase microextraction techniques
PublikacjaDetermination of analytes at trace levels in complex samples (e.g. biological or contaminated water or soils) are often required for the environmental assessment and monitoring as well as for scientific research in the field of environmental pollution. A limited number of analytical techniques are sensitive enough for the direct determination of trace components in samples and, because of that, a preliminary step of the analyte...
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DIFFRACTION PHASE MICROSCOPY FOR OBSERVATION ON RED BLOOD CELLS FLUCTUATION
PublikacjaNowadays 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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Modern trends in solid phase extraction: New sorbent media
PublikacjaBased 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...
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Five-phase squirrel-cage motor. Construction and drive properties
PublikacjaThis 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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Photovoltaic module temperature stabilization with the use of phase change materials
PublikacjaThe worldwide growth of photovoltaics (PVs) has formed an exponential curve for more than four decades. During this period of time, PVs have evolved from a pure niche market of small-scale applications towards becoming a mainstream electricity source. The influence of temperature on the electrical parameters of crystalline silicon solar cells and solar modules is well described in the literature. In order to diminish these effects,...
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Effect of lipid phase composition on autoxidation of water - in - oil emulsion
PublikacjaW pracy przedstawiono ocenę procesu autooksydacji emulsji W/O ze szczególnym uwzględnieniem składu fazy olejowej emulsji na postęp reakcji. Zbadano również wpływ wybranych antyoksydantów i emulgatorów na stabilność sporządzonych układów emulsyjnych.
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Effect of alkyl sulfate on the phase behavior of microemulsions stabilized with monoacylglycerols
PublikacjaIn this study the effect of an anionic surfactant (sodium dodecyl sulfate SDS) and oils (hydrocarbons: C12-C16) on the formation and phase behavior of the systems of oil/monoacylglycerols (MAG):SDS/propylene glycol/water has been investigated. The effects of the surfactant mixture on the phase behavior and the concentrationof water or oil in the systems were studied at three temperatures (50, 55, 60 C). Electrical conductivity...
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THE INFLUENCE OF PHASE SHIFTERS ON THE VOLTAGE STABILITY OF CONNECTED POWER SYSTEMS
PublikacjaThe paper presents the results of simulation tests of connected power systems in which phase shifters were installed on cross-border links. The analysis was carried out in terms of assessing the impact of shifters on node voltage stability. Individual systems were characterized by different balance of active power: deficit or excess. The evaluation of voltage stability was based on the dU/dQ and dU/dP criteria.
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CeIr3: superconductivity in a phase based on tetragonally close packed clusters
PublikacjaWe present the crystallographic analysis, superconducting and spectroscopic characterization, and theoretical modeling of CeIr3. Lattice parameters a = 5.2945(1) Å and c = 26.219(1) Å are found for the R-3m symmetry crystal structure, which are close to the literature values. CeIr3 is a moderate type-II superconductor (κ GL = 17, λ e–p = 0.65) below 2.5 K. Ce ions exhibit a strongly intermediate valence character as evidenced by...
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Sensorless predictive control of three-phase parallel active filter
PublikacjaThe paper presents the control system of parallel active power filter (APF) with predictive reference current calculation and model based predictive current control. The novel estimator and predictor of grid emf is proposed for AC voltage sensorless operation of APF, regardless of distortion of this voltage. Proposed control system provides control of APF current with high precision and dynamics limited only by filter circuit parameters....
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FPGA Acceleration of Matrix-Assembly Phase of RWG-Based MoM
PublikacjaIn this letter, the field-programmable-gate-array accelerated implementation of matrix-assembly phase of the method of moments (MoM) is presented. The solution is based on a discretization of the frequency-domain mixed potential integral equation using the Rao-Wilton-Glisson basis functions and their extension to wire-to-surface junctions. To take advantage of the given hardware resources (i.e., Xilinx Alveo U200 accelerator card),...
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Interconnection of the Customer-Side Resources Using Single Phase VAPF
PublikacjaThe paper introduces method for utilization of the customer-side generated energy using single phase voltage active power filter. Structure and control method of the power electronics converter has been described and some simulation results are shown to prove usefulness of this arrangements. Proposed application realizes the following functions: power quality improvement, uninterruptible supplying and energy costs reduction.
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Measurement method for capacitive sensors for microcontrollers based on a phase shifter
PublikacjaA 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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On Kinetic Nature of Hysteresis Phenomena in Stress-Induced Phase Transformations
PublikacjaA simplest model is developed which demonstrates that hysteresis phenomena in stress-induced phase transformations may have a kinetic nature and follow from the discrepancy between strain rate and characteristic rate of the new phase growth.
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Flow Boiling in Minigap in the Reversed Two-Phase Thermosiphon Loop
PublikacjaThe paper presents the results of experimental investigations of a model of a heat exchanger featuring a minigap, which is perceived as an evaporator for an inverted thermosiphon. The system works with a single component test fluid. The tested evaporator generates pumping power in the test loop in a way similar to the mammoth pump. The tests regarded a module of the heat exchanger, consisting of a hot leg and a cold leg with the...
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Low-energy positron scattering from gas-phase benzene
PublikacjaIn this paper we are presenting calculations of the elastic cross section of positrons with gas-phase benzene for the energy range from 0.25 eV to 9.0 eV. The calculations are done with the molecular R-matrix method for positron-scattering from poly-atomic molecules using a scaling factor to scale the electron-positron interaction. The scaling factor influences the position of the poles of the R-matrix. We adjust the scaling factor...
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First-order magnetic transition in single-crystalline CaFe2As2 detected by 75As nuclear magnetic resonance
PublikacjaPrzedstawione są wyniki badań jądrowego rezonansu magnetycznego na 75As dla kryształów CaFe2As2. Wyniki wskazują, że strukturalne i magnetyczne przejścia w CaFe2As2 są silnie skorelowane i są pierwszego rodzaju.
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The influence of strain on the Verwey transition as a function of dopant concentration: towards a geobarometer for magnetite-bearing rocks
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Mixed electronic-ionic conductivity in transition metal oxide glasses con-taining alkaline ions
PublikacjaOpisano właściwości elektryczne szkieł z tlenkami metali przejściowych zawierających jony metali alkalicznych. Szczególną uwagę zwrócono na typowe zmiany przewodnictwa występujące przy domieszkowaniu tego typu szkieł jonami metali alkalicznych. Porównano przewodnictwo elektryczne szkieł fosforanowo-żelazowych zawierających jony sodu z przewodnictwem szkieł bizmutowo-miedziowych.
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Magnetic Field Influence on the Superconducting Transition in Granular (BiPb)-Sr-Ca-Cu-O Superconductors
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Bonding in Phosphanylphosphinidene Complexes of Transition Metals and their Correlation with Structures, 31 P NMR Spectra, and Reactivities
PublikacjaTheoretical studies of the bonding interactions and most important properties are carried out for isolable phosphanylphosphinidene complexes of transition metals. Three main types of phosphanylphosphinidene complexes are distinguished, based on the way in which the phosphanylphosphinidene ligand bonds to the metal center: (i) side-on complexes of platinum, where the R2Pβ–Pα ligand mimics structural features of free singlet phosphanylphosphinidenes...
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The analysis of firms’ involvement in internationalisation and determinants of its intensity – an analysis for developing and post-transition economies
PublikacjaThe study presents the empirical analysis of firms’ involvement in different forms of internationalisation: export, indirect export, import, indirect import and finally simultaneous exporting and importing. The analysis is based on firm-level data from the World Bank Enterprise Survey (March 2017 release). The empirical part is divided into two stages. Firstly account is taken of firms’ heterogeneity and then a Melitz type analysis...
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Overview of the Synthesis and Catalytic Reactivity of Transition Metal Complexes Based on C═P Bond Systems
PublikacjaThis report provides an overview of the use of phosphaalkenes (C=P) in syntheses of various complexes. Going through successive complexes containing the d-block metals, we sought how this area of chemistry was formed over the years. Additionally, this work contains information on the possible coordination types and means of constructing the complexes. In addition, this review reveals the reactivities of phosphaalkene complexes...
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Innovative Urban Blue Space Design in a Changing Climate: Transition Models in the Baltic Sea Region
PublikacjaWaterfront areas in cities are subject to constant changes. The desire to integrate the transformed waterside areas with the urban fabric involves shaping high-quality public spaces related to water, which are often referred to as urban blue spaces (UBS). The aim of the research was to examine the transformation processes of urban waterfront areas in the Baltic Sea Region and identify emerging transition models and types of blue...
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An Investigation of the Thermal Transitions and Physical Properties of Semiconducting PDPP4T:PDBPyBT Blend Films
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Single-phase power electronics transformer with active functions for smart grid
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IPMSM rotor position estimator based on analysis of phase current derivatives
PublikacjaThis paper describes an algorithm for estimation of IPMSM angular rotor position. The algorithm uses derivatives of motor phase currents resulting from PWM modulation to obtain the rotor position. The presented method is designed for medium- and high-speed range, since it is based on determination of the EMF vector. Algorithm is characterised by a very simple formulae. The calculation of rotor position is performed in every PWM...
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Solid phase extraction of explosives on Ni-doped carbosils prepared by mechanochemistry
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