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The first order phase transition and superconductivity in BaNi2As2 single crystals
PublikacjaDyskutowane są synteza i właściwości fizyczne monokryształów BaNi2As2. BaNi2As2 krystalizuje w strukturze ThCr2Si2, a stałe sieciowe wynoszą odpowiednio: a = 4.112(4) A i c = 11.54(2) A. Pomiar oporu elektrycznego, zmiennopolowej podatności magnetycznej, ciepła właściwego, pokazują objętościowy efekt nadprzewodzący z Tc = 0.7 K.
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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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Phase Transitions in Pores: Experimental and Simulation Studies of Melting and Freezing
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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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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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Recycled Polyurethane as a Second Phase in Thermoset Blends and Its Effect on Thermal Degradation Kinetics Studies
PublikacjaA new approach is introduced in the modification of thermosetting polymer by using different amount of polyurethane of waste origin. The post consumer polyurethane foam coatings are degraded using glycolysis process and the recycled product is further converted into new polyurethane. The blending of recycled polyurethane with epoxy exhibits transparency and produces nanostructures. The effective interaction between two polymers...
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A method for a comprehensive lipidomic analysis of flaxseed (Linum usitatissimum) with the use of LC–Q-TOF-MS and dispersive micro-solid-phase (μDSPE) extraction
PublikacjaFlaxseed (FS) is one of the richest sources of α-linolenic acid oil and lignans, and it is suggested that the consumption of flaxseed may contribute to the prevention of certain chronic diseases such as many types of cancer, diabetes, cardiovascular diseases and cerebrovascular stroke. Here, we demonstrate a new method for comprehensive FS lipidome profiling with the use of LC–Q-TOF-MS and dispersive micro-solid-phase extraction....
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Computational analysis of substituent effects on proton affinity and gas-phase basicity of TEMPO derivatives and their hydrogen bonding interactions with water molecules
PublikacjaThe study investigates the molecular structure of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and its derivatives in the gas phase using B3LYP and M06-2X functional methods. Intermolecular interactions are analyzed using natural bond orbital (NBO) and atoms in molecules (AIM) techniques. NO2-substituted TEMPO displays high reactivity, less stability, and softer properties. The study reveals that the stability of TEMPO derivatives...
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Two-step synthesis of niobium doped Na–Ca–(Mg)–P–Si–O glasses
PublikacjaNiobium doped biosolubility glasses in the Na–Ca–(Mg)–P–Si–O system were prepared by using an untypical two-step synthesis route. The parent glass was melted in air atmosphere at 1350 °C followed by re-melting the glass in Nb crucible with the addition of metallic Mg/Ca powder in the nitrogen atmosphere. The second melting step was carried out at 1450–1650 °C, using an induction furnace. The topography and structure of the obtained...
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In vivo imaging of the human eye using a two-photon excited fluorescence scanning laser ophthalmoscope
PublikacjaBACKGROUND. Noninvasive assessment of metabolic processes that sustain regeneration of human retinal visual pigments (visual cycle) is essential to improve ophthalmic diagnostics and to accelerate development of new treatments to counter retinal diseases. Fluorescent vitamin A derivatives, which are the chemical intermediates of these processes, are highly sensitive to UV light; thus, safe analyses of these processes in humans...
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Computationally efficient two-objective optimization of compact microwave couplers through corrected domain patching
PublikacjaFinding an acceptable compromise between various objectives is a necessity in the design of contemporary microwave components and circuits. A primary reason is that most objectives are at least partially conflicting. For compact microwave structures, the design trade-offs are normally related to the circuit size and its electrical performance. In order to obtain comprehensive information about the best possible trade-offs, multi-objective...
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Identification of two novel mutations in human acute myeloid leukemia cases
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Frequency compensation for two-stage operational amplifiers with improved PSRR characteristic
PublikacjaW pracy została opisana nowa metoda kompensacji częstotliwościowej dwustopniowych wzmacniaczy operacyjnych. Metoda kompensacji gwarantuje uzyskanie stabilnej pracy wzmacniacza operacyjnego przy założeniu że wzmocnienie układu z zamkniętą pętlą sprzężenia zwrotnego jest ograniczone do wartości kilkunastu decybeli. W porównaniu do innych znanych metod kompensacji, zaproponowana metoda umożliwia co najmniej dziesięciokrotne poszerzenie...
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All graphs with paired-domination number two less than their order
PublikacjaLet G=(V,E) be a graph with no isolated vertices. A set S⊆V is a paired-dominating set of G if every vertex not in S is adjacent with some vertex in S and the subgraph induced by S contains a perfect matching. The paired-domination number γp(G) of G is defined to be the minimum cardinality of a paired-dominating set of G. Let G be a graph of order n. In [Paired-domination in graphs, Networks 32 (1998), 199-206] Haynes and Slater...
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Theoretical description of fundamental-harmonic impedance of a two-step electrode reaction
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Electronic correlations in coherent transport through a two quantum dot system
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<title>Colorimetric sensor based on two optical fiber couplers</title>
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Enantioselective comprehensive two-dimensional gas chromatography of lavender essential oil
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Path components of the space of gradient vector fields on the two-dimensional disc
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Doped Two-Dimensional Silicon Nanostructures as a Platform for Next-Generation Sensors
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One Europe, one product, two prices - the price disparity in the EU
PublikacjaThe price dispersion in the European Union in the last fifteen years (1990-2005) is analysed. The analysis of price convergence is examined on aggregate and disaggregate levels. The macro approach is based on Comparative Price Level index calculated as the ratio between PPPs and exchange rate. The disaggregate analysis utilizesactual prices of 148 individual products sold in the 15 capital cities of the EU. The calculations comprise...
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Two dimensional modeling of the flood zones in the Vistula river valley in Warsaw
PublikacjaPrzedstawiono metodę numerycznego wyznaczania stref zagrożenia powodziowego. Transformację fali powodziowej symulowano, używając dwuwymiarowych równań de Saint-Venanta. Zasięg zalewu i strefy zagrożenia powodziowego przedstawiono w systemie GIS. Wykonano analizę zagrożenia powodziowego w dolinie Wisły w Warszawie.
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Reliability model of two-shaft turbine combustion engine with heat regenerator
PublikacjaW artykule przedstawiono możliwość zastosowania teorii procesów semimarkowskich do opisu niezawodności turbinowego silnika spalinowego. Opracowano model niezawodnościowy w formie siedmiostanowego procesu semimarkowskiego, umożliwiający określenie prawdopodobieństw przebywania silnika w stanie zdatności oraz wyróżnionych stanach niezdatności.
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A metastable [(MgF3)2]2− dianion composed of two superhalogen anions
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Stability of an optical displacement sensor using a two-beam polarization interferometer
PublikacjaW artykule przedstawiono wyniki pomiarów stabilności wybranej konfiguracji dwuwiązkowego interferometru polaryzacyjnego. Przedyskutowano źródła występującej niestabilności.
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Toenail selenium level among healthy residents of two polish districts
PublikacjaCelem pracy było badanie zawartości selenu w próbkach paznokci pobranych od mieszkańców Województwa Pomorskiego i Lubuskiego. Wykazano, że średnie stężenia Se w próbkach paznokci wynosiło odpowiednio 0,57 ± 0,10, 0,60 ± 0,16 mg kg-1. Stwierdzono także, że płeć, wiek, wskaźnik masy ciała, status palenia oraz przyjmowanie Se w postaci suplementów diety przez uczestników badania wpływa istotnie statystycznie na poziom...
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Two dimensional modelling of the flood zones in the Vistula river valley in Warsaw
PublikacjaW artykule przedstawiono opis metodyki wyznaczania stref zalewu powodziowego na terenach miejskich. Rozprzestrzenianie się zalewu symulowano przy pomocy dwuwymiarowych równań de Saint-Venanta. Zasięg zalewu i strefy zagrożenia powodziowego przedstawiono w systemie GIS. Wykonano analizę zagrożenia powodziowego w dolinie Wisły w Warszawie.
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Modeling of a re-heat two-stage adsorption chiller by AI approach
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Two-dimensional gel-based serum protein profile of growing piglets
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Comparison of Two Methods for the Determination of Selected Pesticides in Honey and Honeybee Samples
PublikacjaDeveloped and validated analytical methods for the determination of a wide spectrum of pesticide residues in honey and honeybee samples after the modification of QuEChERS extraction in combination with gas chromatography–tandem quadrupole mass spectrometry (GC-MS/MS) and liquid chromatography–tandem quadrupole mass spectrometry (LC-MS/MS) were discussed and compared. The developed methods were evaluated regarding the utilized equipment...
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Two almost homoclinic solutions for second-order perturbed Hamiltonian systems
PublikacjaW niniejszym artykule badamy problem istnienia rozwiązań prawie homoklinicznych (rozwiązań znikających w nieskończonościach) dla układów Hamiltonowskich drugiego rzędu (układów Newtonowskich) z zaburzeniem. Nasz wynik jest uogólnieniem twierdzenia Rabinowitza-Tanaki o istnieniu rozwiązania homoklinicznego dla układów bez zaburzenia [Math. Z. 206 (1991) 473-499]. O zaburzeniu zakładamy, że jest dostatecznie małe w przestrzeni funkcji...
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The homotopy type of the space of gradient vector fields on the two-dimensional disc
PublikacjaWe prove that the inclusion of the space of gradient vector fields into the space of all vector fields on D^2 non-vanishing in S^1 is a homotopy equivalence
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Numerical Simulation of two dimensional flow past a bridge cross section
PublikacjaThis work presents some numerical results concerning application of CFD in civil engineering problems. Selected theoretical aspects of fluid mechanics are elucidated. In the second part of the paper a cross section of upper footbridge of the Bella Sky Hotel in Copenhagen is analysed numerically in the field of wind action.
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Fermentative Conversion of Two-Step Pre-Treated Lignocellulosic Biomass to Hydrogen
PublikacjaFermentative hydrogen production via dark fermentation with the application of lignocellulosic biomass requires a multistep pre-treatment procedure, due to the complexed structure of the raw material. Hence, the comparison of the hydrogen productivity potential of different lignocellulosic materials (LCMs) in relation to the lignocellulosic biomass composition is often considered as an interesting field of research. In this study,...
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Damage detection in rectangular plates by continuous two-dimensional wavelet transform
PublikacjaPraca opisuje zastosowanie dwuwymiarowej transformaty falkowej do detekcji i lokalizacji uszkodzeń w konstrukcji płytowej. Defekt zlokalizowano na podstawie postaci drgań z symulacji numerycznych oraz z badań eksperymentalnych.
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Two-Level Multivariable Control System of Dissolved Oxygen Tracking and Aeration System for Activated Sludge Processes
PublikacjaThe problem of tracking dissolved oxygen is one of the most complex and fundamental issues related to biological processes. The dissolved oxygen level in aerobic tanks has significant influence on behaviour and activity of microorganism inhabiting the plant. Aerated tanks are supplied with air from an aeration system (blowers, pipes, throttling valves, diffusers). It is a complex dynamic system governed by nonlinear hybrid dynamics....
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Mathematical modelling of two-step nitrification-denitrification for treatment of sludge digester liquors: influence of nitrite (NO2-N) on the process kinetics
PublikacjaSeparate treatment of the sludge digester liquors is an alternative for expansion of the mainstream treatment line. In order to reduce the oxygen demand for nitrification and organic carbon demand for denitrification, a shortcut in the nitrogen conversion pathway has been promoted in recent years, i.e. nitrification-denitrification via NO2-N instead of NO3-N. Although NO2-N is a common intermediate product of nitrification and...
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Studies on applicability of new solid-phase microextraction fibers for the selective extraction and determination of short - chain monocarboksylic acids
PublikacjaShort-chain monocarobxylic acids, sometimes referred to as volatile fatty acids (VFA), are a group of low molecular weight alkyl monocarboxylic acids that are widely distributed within the environment. These molecules contain any from 2 to 8 carbon atoms and originate from the anaerobic biodegradation of organic matter such as carbohydrates, proteins, and fats. These compounds are commonly found in the effluents from animal farming,...
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Numerical and experimental investigation of guided ultrasonic wave propagation in non-uniform plates with structural phase variations
PublikacjaThe article presents the results of numerical and experimental investigations of guided wave propagation in aluminum plates with variable thickness. The shapes of plate surfaces have been specially designed and manufactured using a CNC milling machine. The shapes of the plates were defined by sinusoidal functions varying in phase shift, which forced the changes in thickness variability alongside the propagation path. The main aim...
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Miniaturized Solid Phase Extraction techniques for different kind of pollutants analysis: State of the art and future perspectives – PART 1
PublikacjaSolid Phase Extraction (SPE) has been practiced in a modern form for more than half a century. It was constantly developing, driven by the analysts needs. These needs are coming from the importance to select an appropriate analytical method, which should have satisfactory accuracy, precision and sensitivity. In the case of sorbent-based microextraction techniques, the choice of miniaturized variants that meet these requirements...
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Simultaneous Determination of Indolic Compounds in Plant Extracts by Solid-Phase Extraction and High-Performance Liquid Chromatography with UV and Fluorescence Detection
PublikacjaA high-performance liquid chromatographic method with UV and fluorescence detection (HPLC-DAD-FLD) was developed for simultaneous determination of indolic compounds in plant material. Indole-3-carbinol (I3C), indole-3-acetic acid (I3AA), indole-3-acetonitrile (I3ACN), and 3,3′-diindolylmethane (DIM) were used as representative compounds that cover a wide spectrum of indole structures occurring in nature. For concentration and purification...
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A negative effect of carbon phase on specific capacity of electrode material consisted of nanosized bismuth vanadate embedded in carbonaceous matrix
PublikacjaLithium-ion batteries (LIBs) are widely used all over the world. The LIBs belong to a renewable energy source and energy storage devices. The increase in energy demand causes that new materials of higher energy and higher power densities are still under investigation. Herein, we compare electrochemical properties of bismuth vanadate (BiVO4) embedded and not embedded into carbonaceous matrix as an anode material along with structural...
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Induction of G2/M phase arrest and apoptosis of human pancreatic cancer BxPC-3 cells by potenet antitumor 1-nitroacridine derivative C-1748
PublikacjaPancreatic ductal adenocarcinoma (PDA) is among the most lethal human cancers, in part because it is insensitive to many chemotherapeutic drugs. Gemcitabine still remains the best chemotherapeutic agent available for the treatment of advanced pancreatic cancer. However, gemcitabine treatment results in only a marginal survival advantage. Thus, there is a strong need for the continuous development of novel therapeutic agents...
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Modeling of Cardiac Component of Subarachnoid Space Changes in Apnoea Resulting as a Function of Blood Pressure and Blood Flow Parameters - Two Mechanizm of Regulation
PublikacjaExperiments were performed in a group of 19 healthy, non-smoking volunteers. The experiment consisted of three apnoeas, sequentially: 30 s apnoea, 60 s apnoea and maximal, that could be done, apnoea. The breath-hold was separated for 5 minutes rest. The following parameters were measured and obtained for further analysis: blood parameters, artery diameter of the internal carotid artery, end-tidal CO2 in expired air, the cardiac...
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Approximation of Message Inter-Arrival and Inter-Departure Time Distributions in IMS/NGN Architecture Using Phase-Type Distributions
PublikacjaCurrently it is assumed that requirements of the information society for delivering multimedia services will be satisfied by the Next Generation Network (NGN) architecture, which includes elements of the IP Multimedia Subsystem (IMS) solution. In order to guarantee Quality of Service (QoS), NGN has to be appropriately designed and dimensioned. Therefore, proper traffic models should be proposed and applied. This requires determination...
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Nutrient recovery from deammonification effluent in a pilot study using two-step reject water treatment technology
PublikacjaThe aim of this study was to assess the possibility of phosphorus and nitrogen recovery from the liquid fraction of digestates (reject water) pilot study using a two-step technology, where the precipitation of biogenic compounds in the form of magnesium ammonium phosphate (struvite) will be preceded by a deammonification process. The tests confirmed the possibility of nutrient recovery from deammonification effluent. A removal...
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Method of earth fault loop impedance measurement without nuisance tripping of RCDs in 3-phase low-voltage circuits
PublikacjaVerification of electrical safety in low-voltage power systems includes the measurement of earth fault loop impedance. This measurement is performed to verify the effectiveness of protection against indirect contact. The widespread classic methods and meters use a relatively high value of the measuring current (5–20) A, so that they are a source of nuisance tripping of residual current devices (RCDs). The meters dedicated to circuits...
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Diagnostic Analysis of Exhaust Gas with A Quick-Changing Temperature from a Marine Diesel Engine Part II / Two Factor Analysis
PublikacjaThe article presents a continuation of research carried out to determine the effect of input parameters (changes in engine structure parameters) on selected output parameters (diagnostic measures), based on quickly changing exhaust gas temperature. A method of determining the simultaneous influence of two input factors (the structure parameter and the engine load) on one output factor was presented, as well as an evaluation...
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Comparison of hydrochemistry and organic compound transport in two non-glaciated high Arctic catchments with a permafrost regime (Bellsund Fjord, Spitsbergen)
PublikacjaAn increase in air temperature related to climate change results in the retreat of glaciers, the degradation of permafrost, and the expansion of glacier-free areas in the polar regions. All these processes lead to changes in the Arctic landscape. They influence the hydrochemistry of streams and rivers fed by glaciers and thawing permafrost. In this study, we examine eighty two water samples from two non-glaciated catchments with...
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Solid Phase Micro-Extraction, a Versatile and Handy Tool in Environmental Trace Organic Analysis, Gets a New Class of Coatings, Polymeric Ionic Liquids
PublikacjaSolid phase microextraction (SPME) fundamentals, characteristics and application are described. The special stress is put on characteristics of sorbents used as SPME fiber coatings. Description of commercially available fibers and the present-day trends in development of new sorbents for SPME are given. Discussion is focused on possibility of application of ionic liquids (IL) and polymeric ionic liquids (PIL) as SPME fiber coatings....