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Wyniki wyszukiwania dla: phase structure
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Stability of liquid film formed due to impingement of a two-phase jet
PublikacjaPrzedstawiono analizę teoretyczną i badania eksperymentalne zjawiska rozrywania się warstwy cieczy powstałej na powierzchni ciała stałego z uderzającej strugi.
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Extended phase diagram of RNiC2 family: Linear scaling of the Peierls temperature
PublikacjaPhysical properties for the late-lanthanide-based RNiC2 (R = Dy, Ho, Er, and Tm) ternary compounds are reported. All the compounds show antiferromagnetic ground state with the Néel temperature ranging from 3.4 K for HoNiC2 to 8.5 K for ErNiC2. The results of the transport and galvanomagnetic properties confirm a charge density wave state at and above room temperature with transition temperatures TCDW = 284, 335, 366, and 394 K for...
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Tuning the ferromagnetic phase in the CDW compound SmNiC2 via chemical alloying
PublikacjaWe report a study on tuning the charge density wave (CDW) ferromagnet SmNiC2 to a weakly coupled superconductor by substituting La for Sm. X-ray diffraction measurements show that the doped compounds obey Vegard’s law, where La (Lu) alloying expands (shrinks) the lattice due to its larger (smaller) atomic size than Sm. In the series Sm1−xLaxNiC2, CDW transition (TCDW =148K) for SmNiC2 is gradually suppressed, while the ferromagnetic...
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EFFECT OF NANOFLUID CONCENTRATION ON TWO-PHASE THERMOSYPHON HEAT EXCHANGER PERFORMANCE
PublikacjaAn approach – relaying on application of nanofluid as a working fluid, to improve performance of the two-phase thermosyphon heat exchanger (TPTHEx) has been proposed. The prototype heat exchanger consists of two horizontal cylindrical vessels connected by two risers and a downcomer. Tube bundles placed in the lower and upper cylinders work as an evaporator and a condenser, respectively. Distilled water and nanofluid water-Al2O3...
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Simulation of the remanence influence on the transient states in a single-phase multiwinding transformer
PublikacjaThis paper presents the mathematical model of a single-phase multi-winding core type transformer taking into account magnetic hysteresis phenomenon based on the feedback Preisach model (FPM). The set of loop differential equations was developed for a K-th winding transformer model where the flux linkages of each winding includes flux Φ common to all windings as a function of magneto motive force Θ of all windings. The first purpose...
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Recognition of two-phase flow patterns with the use of dynamic image analysis
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Mechanism of a Four-Phase Liquid Membrane Oscillator Containing Hexadecyltrimethylammonium Bromide
PublikacjaBadano zachowanie nitrometanowego oscylatora z membraną ciekłą zawierającego kationowy surfaktant. Początkowo układ składał się z trzech faz: wodnej donorowej zawierającej surfaktant i etanol, membrany ciekłej (kwas pikrynowy w nitrometanie) oraz fazy wodnej akceptorowej zawierającej sacharozę. Podczas procesu oscylacyjnego wytwarzała się nowa fazą X między membraną ciekłą, a fazą akceptorową. Stwierdzono oscylacje różnicy potencjału...
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Thermotropic Biaxial Nematic Phase in Liquid Crystalline Organo-Siloxane Tetrapodes
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Dissociative electron attachment to gas phase thiothymine: experimental and theoretical approaches
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Extended non-linear relations of elastic shells undergoing phase transitions
PublikacjaThe non-linear theory of elastic shells undergoing phase transitions was proposed by two first authors in J. Elast. 79, 67-86 (2004). In the present paper the theory is extended by taking into account also the elastic strain energy density of the curvilinear phase interface as well as the resultant forces and couples acting along the interface surface curve itself. All shell relations are found from the variational principle of...
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Using phase of short-term Fourier transform for evaluation of spectrogram performance
PublikacjaThe concept of spectrogram performance evaluation which exploits information on phase of short-term Fourier transform (STFT) is presented. A spectrograph which is time-frequency analyzing tool, is compared to a filter bank that demultiplexes a signal. Local group delay (LGD) and channelized instantaneous frequency (CIF) is obtained for each filtered component signal. In presented solution the performance is evaluated using so-called...
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Composite Bioelectrodes Based on Lipidic Cubic Phase with Carbon Nanotube Network
PublikacjaElektrody z węgla szklistego modyfikowane fazą kubiczną z siecią nanorurek zastosowano do enzymatycznej redukcji tlenu katalizowanej przez lakazę. Zastosowanie nanorurek obniżyło nadpotencjał redukcji tlenu o 0,5 V. W celu zwiększenia gęstości prądu redukcji tlenu zastosowano znany mediator przeniesienia elektronów - ABTS. Mediator adsorbowano na nanorurkach lub wiązano kowalencyjnie z końcami nanorurek. Kowalencyjne związanie...
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Solventless sample preparation techniques based on solid- and vapour-phase extraction
PublikacjaThe 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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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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Losses Model of the WPT System with Single-Phase T-Type Inverter
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Riboflavin binding protein—Chiral stationary phase: Investigation of retention mechanism
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Pressure-induced phase transition in LiLuF4:Pr3+investigated by an optical technique
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Optical processes in YVO4:Eu3+across zircon-to-scheelite phase transition
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A review of theoretical and practical aspects of solid-phase microextraction in food analysis.
PublikacjaSPME (mikroekstrakcja do fazy stacjonarnej) to szybka, nowoczesna technika przygotowania próbki do analizy. W niniejszej pracy dokonano przeglądu zastosowania techniki SPME do badania zanieczyszczeń żywności i analizy jej naturalnych składników. Praca zawiera również krótki teoretyczny opis zasad działania techniki SPME.
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Phase compensation scheme for feedforward linearised CMOS operational transconductance amplifier.
PublikacjaW pracy opisano technikę kompensacji charakterystyk fazowych linearyzowanego metodą feedforward operacyjnego wzmacniacza transkonduktancyjnego CMOS. Wykazano, że proponowana koncepcja układowa prowadzi do znacznej poprawy liniowości charakterystyki przejściowej wzmacniacza oraz do rozszerzenia zakresu liniowości prądu wyjściowego. Ponadto w pracy przeprowadzono analizę charakterystyk częstotliwościowych, w wyniku której otrzymano...
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The II phase metabolism of endogenous and exogenous compounds, including antitumor chemotherapeutics
PublikacjaThe II phase metabolism, it is a set of metabolism and excretion pathways of endogenous as well as exogenous compounds including xenobiotics. UDP-glucuronyltransferases (UGTs; EC 2.4.1.17) are the most crucial representatives of II phase enzymes, which are responsible for the transformation of bilirubine and bile acids, steroids and thyroid hormones and lipids. Exogenous compounds, including drugs, carcinogens, environmental pollutants...
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The use of numerical methods for the analysis of phase phenomena in multi element antennas.
PublikacjaW artykule zostały zaprezentowane wyniki analizy wpływu wzajemnej i własnej impedancji promieniowania na fazę sygnału odbieranego przez antenę wieloelementową. Obliczenia dokonano dla elektrycznego modelu zastępczego Mason`a przetwornika ultradźwiękowego.
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Simulation and Experiment of a Compact Wideband 90^{circ} Differential Phase Shifter
PublikacjaArtykuł przedstawia projekt i analizę kompaktowego różnicowego przesuwnika fazy, który jest rozwinięciem konfiguracji zaproponowanej Abbosha poprzez modyfikację obciążenia wrót. Zaproponowana konfiguracja zawiera 3dB sprzęgacz kierunkowy z wrotami transmisyjnymi i sprzężonymi zakończonymi obciążeniami reaktancyjnymi. W artykule przedstawiono model teoretyczny prezentujący zasadę działania układu i jego projekt. Uzyskane wyniki...
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Testing Stability of Digital Filters Using Optimization Methods with Phase Analysis
PublikacjaIn this paper, novel methods for the evaluation of digital-filter stability are investigated. The methods are based on phase analysis of a complex function in the characteristic equation of a digital filter. It allows for evaluating stability when a characteristic equation is not based on a polynomial. The operation of these methods relies on sampling the unit circle on the complex plane and extracting the phase quadrant of a function...
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Single-phase power electronics transformer with active functions for smart grid
PublikacjaThis 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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Concentration levels of selected analytes in the gas phase of an e-cigarette aerosol
PublikacjaThe aerosols generated from e-cigarettes are composed of liquid and gas phases resulting from vapourized e-liquid. The apportioning of substances from e-liquid into the liquid and gas phases during e-cigarette use has not been extensively studied. Partitioning of e-liquid components between the gas and the liquid phase of the aerosol influences the substances inhaled and exhaled by the users, leading to second-hand exposure. It...
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Experimental investigation of two-phase thermosyphon heat exchanger charged with acetone
PublikacjaThis paper presents thermal characteristics of prototype of a two-phase thermosyphon heat exchanger (TPTHEx) charged with acetone as a working fluid. The TPTHEx consists of two horizontal cylindrical vessels connected by two risers and a downcomer. Tube bundles placed in the lower and upper cylinders work as an evaporator and a condenser, respectively. The tested TPTHEx operates in a vacuum. Therefore, the working liquid is boiled...
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HYDROGEN PRODUCTION PERFORMANCE IN THERMOCATALYTIC REACTOR BASED ON THE INTERMETALLIC PHASE OF NI3AL
PublikacjaThe main aim of the following paper is mathematical modelling for momentum, heat and mass transfer, which is accompanied by chemical surface reactions of the flow of the mixture helium and methanol. The thermocatalytic devices used for decomposition of hydrocarbons incorporate vertical microchannels coupling at the ends and heated to 500 oC at the walls. The results of the experiment were compared with CFD calculations to calibrate...
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DETERMINATION OF SP3 FRACTION IN ta-C COATING USING XPS AND RAMAN SPECTROSCOPY
PublikacjaThe paper presents results of studies on the structure of tetrahedral amorphous carbon films (ta-C) with a thickness in the range from 20 to 280 nm, deposited using pulsed vacuum arc technique with an electromagnetic Venetian blind plasma filter. The results of the phase structure analysis, obtained using visible Raman spectroscopy and UV Raman spectroscopy methods, showed a strong dependence of the results on the presence, on...
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Spatial Evolution of the European Container Ports’ System in Perspective of the Location Theory
PublikacjaThe maritime container terminal is nowadays a spatially incoherent object. From the functional point of view it ends, where their most external components are located. The process of location splitting of container terminals is a new phase of their discrete growth. The external container facilities are being built to improve effectivness of the logistic chain in the hinterland. The new components of container terminals have very...
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A Multifunctional Microwave Filter/Sensor Component Using a Split Ring Resonator Loaded Transmission Line
PublikacjaThis research is focused on the design and realiza2 tion of a microwave component with multifunctional filter/sensor 3 operation using a resonator-loaded transmission line (TL). It is 4 shown that while the structure acts as a bandstop filter, the 5 phase of the reflection coefficient from the loading resonator(s) 6 on a movable layer can be used for displacement sensing, thus 7 allowing for combining filtering with sensing in...
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An asymmetrical λ-foot of condensing steam flow in the IMP PAN nozzle
PublikacjaIn the present paper we have focused on the precise prediction of the spontaneous condensation phenomena in wet steam flow. Novelty of our approach lies on modelling both the moment of initiation of a phase transition, as well as the moment of its reverse progress - called here re-vaporization of the condensate phase. The practical issue is to elaborate of a model of spontaneous condensation/vaporization of water steam flow...
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Synthesis and physical properties of the 10.6 K ferromagnet NdIr3
PublikacjaThe magnetic, transport, and thermodynamic properties of NdIr3 are reported. Its PuNi3-type crystal structure (space group R−3m), with lattice parameters a= 5.3262(1)Å and c=26.2218(3)Å, was confirmed by powder x-ray diffraction. Our measurements indicate that NdIr3 exhibits a previously unreported paramagnetic to ferromagnetic phase transition below TC=10.6 K(determined by using the Arrott plot). The magnetic susceptibility obeys...
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Conductivity, structure, and thermodynamics of Y2Ti2O7–Y3NbO7 solid solutions
PublikacjaThe defect fluorite yttrium niobate Y3NbO7 and pyrochlore yttrium titanate Y2Ti2O7 solid solutions have been synthesized via a solid state synthesis route. The resulting stoichiometry of the oxides is Y2+xTi2−2xNbxO7, where x = 0 to x = 1. All of the samples were single-phase; however, for those with a predominant fluorite phase, a small amount of additional pyrochlore phase was detected. The volume of the solid solution unit cells...
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PRESSURE DROP OF HFE7000 AND HFE7100 IN FLOW CONDENSATION IN MINICHANNELS WITH ACCOUNT OF NON-ADIABATIC EFFECTS
PublikacjaFlow boiling and flow condensation are often regarded as two opposite or symmetrical phenomena involving the change of phase. There is a temptation to describe both these phenomena with one only correlation. From amongst the structures present in flow boiling and flow condensation at least the annular flow structure seems to be mostly appropriate to the common modeling. However, the shear stress acting between vapor phase and liquid...
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Modification of gradient HPLC method for determination of small molecules' affinity to human serum albumin under column safety conditions: Robustness and chemometrics study
PublikacjaIn the early stages of drug discovery, beyond the biological activity screening, determining the physicochemical properties that affect the distribution of molecules in the human body is an essential step. Plasma protein binding (PPB) is one of the most important investigated endpoints. Nevertheless, the methodology for measuring %PPB is significantly less popular and standardized than other physicochemical properties, like lipophilicity....
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A novel microstrip dual-layer rat-race coupler with compact size and enhanced bandwidth
PublikacjaMicrowave hybrid couplers are crucial components of mixers, phase shifters, amplifiers and other high-frequency systems. Conventional couplers are characterized by large size which limits their usefulness in modern applications. In this work, a novel compact rat-race coupler with enhanced bandwidth has been proposed. The structure consists of six compact microstrip resonant cells. It is implemented on two separate layers which permits...
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Pseudo-superparamagnetic behaviour of bariumhexaferrite particles
PublikacjaThe effect of hexadecyltrimethylammonium bromide (CTAB) addition on the crystal structure, morphology,and magnetic properties of co-precipitated hexagonal barium ferrite was investigated. For afixed amount ofsurfactant, different Fe3+concentrations and Fe3+/Ba2+ratios were used to optimize the formation ofsingle-phase barium ferrite particles. The results indicated that the obtained ferrite particles exhibitedcoercivity changes...
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Praseodymium Orthoniobate and Praseodymium Substituted Lanthanum Orthoniobate: Electrical and Structural Properties
PublikacjaIn this paper, the structural properties and the electrical conductivity of La1−xPrxNbO4+δ (x = 0.00, 0.05, 0.1, 0.15, 0.2, 0.3) and PrNbO4+δ are presented and discussed. All synthesized samples crystallized in a monoclinic structure with similar thermal expansion coefficients. The phase transition temperature between the monoclinic and tetragonal structure increases with increasing praseodymium content from 500 ◦C for undoped...
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Piezoresponse force microscopy and dielectric spectroscopy study of Ba0.6Sr0.4TiO3 thin films
PublikacjaResearch on synthesis, characterization and determination of processing – structure – property relationships of commercially important ferroelectric thin films has been performed. The sol-gel-type solution deposition technique was applied to produce good quality thin films of Ba0.6Sr0.4TiO3 (BST60/40) chemical composition on the stainless steel substrates. The thin films were characterized in terms of their microstructure, crystal...
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Four Level Diode-Clamped Back-To-Back Converter with Active DC Link Voltage Control
PublikacjaThis article presents the design and control of 4L-DC back-to-back converter. To solve the DC link voltage balancing problem in four-level converter a new three-level double chopper topology based on PO-PWM modulation was designed and successfully tested. Also, the paper describes two phase space vector pulse width modulation 2P-SVPWM based on the shape function of finite elements. The control structure with modified Dead-Beat...
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Interrelationship between total volatile organic compounds emissions, structure and properties of natural rubber/polycaprolactone bio-blends cross-linked with peroxides
PublikacjaNatural rubber/polycaprolactone (NR/PCL) bio-based blends with different organic peroxides were prepared using an internal batch mixer and subsequently cross-linked at 170°C. Two types of commonly used organic peroxides, dicumyl peroxide and di(tert-butylperoxyisopropyl)benzene peroxide, were applied as free-radical initiator. Cross-linking efficiency of NR/PCL blends were investigated using oscillating disc rheometer measurements,...
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Structure and performance properties of environmentally-friendly biocomposites based on poly(ɛ-caprolactone) modified with copper slag and shale drill cuttings wastes
PublikacjaThe potential application of two types of industrial wastes, drill cuttings (DC) and copper slag (CS), as silica-rich modifiers of poly(ɛ-caprolactone) (PCL) was investigated. Chemical structure and physical properties of DC and CS fillers were characterized using X-ray diffractometer, X-ray fluorescence spectroscopy, particle size and density measurements. PCL/DC and PCL/CS composites with a variable content of filler (5 to 50...
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Towards azeotropic MeOH-MTBE separation using pervaporation chitosan-based deep eutectic solvent membranes
PublikacjaDeep eutectic solvents (DESs) are a new class of solvents that can offset some of the major drawbacks of common solvents and ionic liquids. When dealing with the preparation of dense membranes, the use of DESs is still challenging due to their low compatibility with the polymer phase. In this research, a novel L-proline:sulfolane (molar ratio 1:2) DES was synthesized and used for the preparation of more sustainable bio-based membranes...
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Analysis of IMS/NGN call processing performance using phase-type distributions
PublikacjaThis work is a continuation of our research on the traffic model dedicated for design and analysis of the Next Generation Network (NGN), which is standardized for distribution of current and future multimedia services based on the IP Multimedia Subsystem (IMS). Our analytical and simulation models allow evaluation of mean Call Set-up Delay E(CSD) as well as mean Call Disengagement Delay E(CDD) in a single domain of IMS/NGN. Ensuring...
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Phase Change Thermal Energy Storage – The Experience of the Materials Preparation for the Specific Applications.
PublikacjaThermal energy storage and temperature stabilization is very important in many engineering applications. There are three kinds of thermal energy storage: sensible heat storage, latent heat storage and reversible chemical reaction heat storage. Phase change materials (PCM) absorb, store and release large amounts of energy in the form of latent heat, at constant temperature, called the transition temperature. The amount of heat...
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Analysing the potential for application of the phase shift method in endoscopic examination of marine engines
PublikacjaThe article presents theoretical principles of image processing in digital endoscopy which makes use of a miniaturised spectral scanner “PhaseProbe” designed by General Inspection Technologies LP, the producer of the measuring videoendoscope Everest XLG3. The technology of optoelectronic 3D mapping of the examined surface, which consists in measuring the phase shift between the emitted and reflected light waves, is briefly described....
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The Possibility of Phase Change Materials (PCM) Usage to Increase Efficiency of the Photovoltaic Modules
PublikacjaSolar energy is widely available, free and inexhaustible. Furthermore this source of energy is the most friendly to the environment. For direct conversion of solar energy into useful forms like of electricity and thermal energy, respectively photovoltaic cells and solar collectors are being used. Forecast indicate that the first one solution will soon have a significant part in meeting the global energy demand. Therefore it is...
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Change of the Phase Composition and Strength of Al2O3–ZrO2-Ceramic After Hydrothermal Aging
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