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Wyniki wyszukiwania dla: MULTIPULSE VOLTAGE CONVERTERS, MATRIX CONVERTERS COUPLED INDUCTORS, INDUCTIVE CURRENT SPLITTE/MERGERR
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Detekcja uszkodzeń w kratownicy kompozytowej z zastosowaniem fal giętno-scinających.Damage detection in composite truss by application coupled flexural - shearwaves.
PublikacjaW pracy przedstawiono zastosowanie fal spręzystych do detekcji peknięć w kratownicy kompozytowej.
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Modelling of Hydraulic Fracturing in Rocks in Non-isothermal Conditions Using Coupled DEM/CFD Approach with Two-Phase Fluid Flow Model
PublikacjaSkała łupkowa jest materiałem silnie niejednorodnym, nieciągłym i porowatym. W warunkach nieizotermicznych ruch płynu w układzie porów i kapilar jest silnie sprzężony z przenoszeniem ciepła. Przebieg szczeliny hydraulicznej silnie zależy od stopnia nasycenia skały. Opracowano innowacyjny model termo-hydro-mechaniczny oparty na modelu DEM w celu szczegółowego śledzenia frakcji ciecz/gaz w porach i pęknięciach pod kątem ich różnej...
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Hydraulic fracturing process in rocks – small-scale simulations with a novel fully coupled DEM/CFD-based thermo-hydro-mechanical approach
PublikacjaW artykule przedstawiono dwuwymiarową (2D) symulację numeryczną szczelinowania hydraulicznego w małej skali przeprowadzoną w próbkach skał posiadających pojedynczą szczelinę wtryskową. Wykorzystano unikalny model termo-hydro-mechaniczny (THM) w skali porów oparty na DEM/CFD do symulacji dwufazowego laminarnego przepływu płynu (wody i gazu) z przenoszeniem ciepła w nienasyconych materiałach porowatych o niskiej porowatości. Korzystając...
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Fixed Pattern Noise Reduction and Linearity Improvement in Time-Mode CMOS Image Sensors
PublikacjaIn the paper, a digital clock stopping technique for gain and offset correction in time-mode analog-to-digital converters (ADCs) has been proposed. The technique is dedicated to imagers with massively parallel image acquisition working in the time mode where compensation of dark signal non-uniformity (DSNU) as well as photo-response non-uniformity (PRNU) is critical. Fixed pattern noise (FPN) reduction has been experimentally validated...
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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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Diagnostic Utility of Selected Matrix Metalloproteinases (MMP-2, MMP-3, MMP-11, MMP-26), HE4, CA125 and ROMA Algorithm in Diagnosis of Ovarian Cancer
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Photoprotection and Antiaging Activity of Extracts from Honeybush (Cyclopia sp.)—In Vitro Wound Healing and Inhibition of the Skin Extracellular Matrix Enzymes: Tyrosinase, Collagenase, Elastase and Hyaluronidase
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Power Grid Frequency Estimation Based on Zero Crossing Technique Using Least Squares Method to Approximate Sampled Voltage Signal Around Zero Level
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Zastosowanie algorytmu ewolucyjnego do uczenia neuronowego regulatora napięcia generatora synchronicznego. Evolutionary algorithm for training a neural network of synchronous generator voltage controller
PublikacjaNajpopularniejsza metoda uczenia wielowarstwowych sieci neuronowych -metoda wstecznej propagacji błędu - charakteryzuje się słabą efektywnością. Z tego względu podejmowane są próby stosowania innych metod do uczenia sieci. W pracy przedstawiono wyniki uczenia sieci realizującej regulator neuronowy, za pomocą algorytmu ewolucyjnego. Obliczenia symulacyjne potwierdziły dobrą zbieżność algorytmu ewolucyjnego w tym zastosowaniu.
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Low cost set-up for supercapacitors parameters evaluation
PublikacjaSupercapacitors are capable to store relatively high amount of energy comparing to its mass. Growing number of these devices applications requires development of new testing methods. Standard methods of evaluation of supercapacitor parameters, as cycling voltammetry, CV, galvanostatic cycling with potential limitation, GCPL, impedance measurements, require equipment of high cost...
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Przekształtnik prądu jako sterownik w układach napędowych z silnikami indukcyjnymi
PublikacjaThe circuits used for power conversion applied in drives with electric machines are classified into two groups: voltage source inverters (VSI) and current source inverters (CSI). Application of the current source inverter results in better properties of drive than application of voltage source inverter because there is no output filter. The development of power electronics and especially the IGBTs, in which on/off-times are very...
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Evolution of the HVDC Link Connecting Offshore Wind Farms to Onshore Power Systems
PublikacjaThis paper presents an overview of the DC link development and evolution dedicated to HVDC structure for connecting offshore wind power plants to onshore power systems. The growing demand for the green energy has forced investors in power industry to look for resources further out at sea. Hence, the development of power electronics and industrial engineering has enabled offshore wind farms to be situated further from the shore...
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Accurate Computation of IGBT Junction Temperature in PLECS
PublikacjaIn the article, a new method to improve the accuracy of the insulated-gate bipolar transistor (IGBT) junction temperature computations in the piecewise linear electrical circuit simulation (PLECS) software is proposed and described in detail. This method allows computing the IGBT junction temperature using a nonlinear compact thermal model of this device in PLECS. In the method, a nonlinear compact thermal model of the IGBT is...
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An Overview of Bidirectional EV Chargers: Empowering Traction Grid-Powered Chargers
PublikacjaIn recent years, the number of electric vehicles has been at least doubling year after year. As a result, today electric vehicles already account for approximately 10% of the global automotive market, which positively affects environment in urbanized areas. However, to take full advantage of the EV integration it is necessary to use renewable sources for their charging; optimally place charging stations/terminals; optimally manage...
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Study of Phase Transitions Occurring in a Catalytic System of ncFe-NH3/H2 with Chemical Potential Programmed Reaction (CPPR) Method Coupled with In Situ XRD
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Determination of non-steroidal anti-inflammatory drugs in natural waters using off-line and on-line SPE followed by LC coupled with DAD-MS
PublikacjaOpisano dwie metody pozwalające na jednoczesne oznaczanie zawartości niesterydowych leków przeciwzapalnych (difluisal, diklofenak, naproksen, tolmetin, fenoprofen, ibuprofen) w próbkach wodnych. Próbki przygotowywano do analizy z użyciem techniki ekstrakcji do fazy stałej (off-line i on-line). Natomiast oznaczeń końcowych dokonano z użyciem LC-DAD-MS. Sprawdzono kilka różnych kolumienek ekstrakcyjnych i wybrano RP-18 jako najlepsze...
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A constitutive model for concrete based on continuum theory with non-local softening coupled with eXtended Finite Element Method. Computational Modelling of Concrete Structures,
PublikacjaArtykuł omawia model połączony ciągły-nieciągły do modelowania stref lokalizacji i rys w betonie niezbrojonym. Obliczenia wykonano stosując rozszerzoną metodę elementów skończonych. Wyniki numeryczne porównano z doświadczeniami.
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Differential scanning calorimetry for authentication of edible fats and oils - What can we learn from the past to face the current challenges?
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European Society of Hypertension Working Group on Obesity Obesity-induced hypertension and target organ damage: current knowledge and future directions
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Antibacterial Activity of Fructose-Stabilized Silver Nanoparticles Produced by Direct Current Atmospheric Pressure Glow Discharge towards Quarantine Pests
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The influence of stabilizers on the production of gold nanoparticles by direct current atmospheric pressure glow microdischarge generated in contact with liquid flowing cathode
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Kinematyka jako odpowiedź na współczesną potrzebę tworzenia przestrzeni = KINEMATICS AS AN ANSWER TO THE CURRENT NEED TO CREATE A RE-CONFIGURABLE SPACE
PublikacjaPrzestrzeń re-konfigurowalna pojawiły się w sztuce i architekturze już w pierwszej połowie XX wieku jako forma odpowiedzi na na pytania, które stawia przed nią świat. Nasze życie i potrzeby zmieniają się niesamowicie dynamicznie. Postfordowski model społeczeństwa sprzyja generowaniu zjawisk, których jeszcze rok temu nie brano pod uwagę. Stąd architektura próbuje stanowić odpowiedź na problemy jeszcze niezaistniałe. Jedną z jej...
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System pomiarowy do sprawdzania dokładności elementów układu pomiaru prądu. Measuring system for testing the current measuring system components
PublikacjaPrzedstawiono badany układ pomiarowy składający się z przetworników pomiaro-wych, filtrów, komputera z kartą akwizycji danych. Zaprezentowano skompute-ryzowany system pomiarowy do badania niepewności pomiaru układem pomiarowym.Podano wyniki badań.
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Preexisting High Expression of Matrix Metalloproteinase-2 in Tunica Media of Saphenous Vein Conduits Is Associated with Unfavorable Long-Term Outcomes after Coronary Artery Bypass Grafting
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Enzymatic cleavage of specific dipeptide conjugated with ferrocene as a flexible ultra-sensitive and fast voltammetric assay of matrix metalloproteinase-9 considered a prognostic cancer biomarker in plasma samples
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Effect of Porosity on the Thermo-Mechanical Behavior of Friction-Stir-Welded Spark-Plasma-Sintered Aluminum Matrix Composites with Bimodal Micro- and Nano-Sized Reinforcing Al2O3 Particles
PublikacjaThe thermo-mechanical behavior of nanosized Al2O3 particles reinforcing aluminum was analyzed in the present paper. The material was prepared by spark plasma sintering and friction stir welding. The thermal stresses affecting the composite behavior during welding were modeled through COMSOL MultiPhysics, and the results were validated by the analyses of the composites’ mechanical properties. The spark-plasma-sintered materials...
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Conducted emi propagation modelling in the wound components.
PublikacjaThe modelling of EMC behaviour of power electronics converters require specific models of devices which are adequate in a wide frequency range. A novel equivalent-circuit model of the inductor, suitable for EMC applications, has been developed and validated. The model can be used for the analyses of wounded components' behaviour in the conducted-EMI frequency range. The parameters of the proposed model can be evaluated based on...
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Receiver of Doppler multistatic system for moving target detection and tracking
PublikacjaThe article presents a method for solving major structural problems that occur in the receiver used in the multistatic Doppler system, aimed at determination of the trajectory and velocity of a moving target. In the system two transmitters emit acoustic continuous sinusoidal waves at different frequencies. The signals, scattered from a moving target are received by four hydrophones. Beside of the echoes, much larger signals coming...
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Speed sensorless ac drive with inverter output filter and fault detection using load torque signal
PublikacjaIn this paper, a sensorless induction motor (IM) drive using speed observer system is presented. The system includes load torque computation for gear fault detection. Nonlinear control method is adopted for controlling the motor over a wide speed range. An LC filter for smoothing current and voltage waveforms is used at the output of the voltage inverter. The use of filter imposes more building of the used observer to avoid using...
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Measurement methods for assessing insulation condition of underground pipelines
PublikacjaThe paper discusses the most frequently applied measurement methods for assessing the quality of external insulation along pipelines and detecting defect locations in the protective coating. The quality of coating along a given pipeline section under investigation is assessed by determining unitary resistance of the coating, which is calculated on the basis of measurement results obtained along a pipeline subjected to cathodic...
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DETERMINATION OF POLYCYCLIC AROMATIC HYDROCARBONS IN SOIL SAMPLES USING ULTRASONIC PROBE AND SALT-ASSISTED LIQUID-LIQUID EXTRACTION COUPLED WITH HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY
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Silica-Based Ionogels: Nanoconfined Ionic Liquid-Rich Fibers for Headspace Solid-Phase Microextraction Coupled with Gas Chromatography–Barrier Discharge Ionization Detection
PublikacjaIn this work, hybrid silica-based materials with immobilized ionic liquids (ILs) were prepared by sol–gel technology and evaluated as solid-phase microextraction (SPME) fiber coatings. High loadings of the IL 1-methyl-3-butylimidazolium bis(trifluoromethylsulfonyl)imide ([C4MIM][TFSI]) were confined within the hybrid network. Coatings composition and morphology were evaluated using scanning electron microscopy and energy dispersive...
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Discussion on “Coupled effective stress analysis of insertion problems in geotechnics with the Particle Finite Element Method” by L. Monforte, M. Arroyo, J.M. Carbonell, and A. Gens
PublikacjaAddressed here is the Particle Finite Element Method (PFEM) modelling of undrained CPTu penetration with regard to a reference analytical solution based on the Spherical Cavity Expansion Method (SCEM). Also discussed is the choice of the soil model and its parameters. The effect of cone interface friction on CPTu simulation is analyzed in a series of penetration tests using Arbitrary Lagrangian-Eulerian (ALE) and Updated Lagrangian...
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A 1-nS 1-V Sub-1-µW Linear CMOS OTA with Rail-to-Rail Input for Hz-Band Sensory Interfaces
PublikacjaThe paper presents an operational transconductance amplifier (OTA) with low transconductance (0.62–6.28 nS) and low power consumption (28–270 nW) for the low-frequency analog front-ends in biomedical sensor interfaces. The proposed OTA implements an innovative, highly linear voltage-to-current converter based on the channel-length-modulation effect, which can be rail-to-rail driven. At 1-V supply and 1-Vpp asymmetrical input driving,...
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Effect of processing parameters on the cyclic behaviour of aluminium friction stir welded to spark plasma sintered aluminium matrix composites with bimodal micro-and nano-sized reinforcing alumina particles
PublikacjaUnderstanding the cyclic behaviour of Alumina reinforced Aluminium composites (Al-A2O3) was of critical importance, for their further application in the different industrial sectors. The present study is focussing on the cyclic behaviour of the Al-Alumina nanocomposite produced through the combination of spark plasma sintering (SPS) method and friction stir welding (FSW). The added Alumina with total content of 10% is the combination...
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Electrochromic foil-based devices: optical transmittance and modulation range, effect of ultraviolet irradiation,and quality assessment by 1/f current noise
PublikacjaPrzedstawiono technologię wytwarzania elementów wykazujących zjawisko elektrochromizmu - zmiany transmitancji optycznej pod wpływem gromadzenia ładunku. Pokazano, że zastosowanie warstwy odbijającej może poprawić stopień zmian transmitancji optycznej. Ponadto, pokazano, że zjawiska losowe generujące szum typu 1/f w tych elementach może być wykorzystane do oceny ich jakości.
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Current understanding of the effects of inspiratory resistance on the interactions between systemic blood pressure, cerebral perfusion, intracranial pressure, and cerebrospinal fluid dynamics
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Development of direct-current, atmospheric-pressure, glow discharges generated in contact with flowing electrolyte solutions for elemental analysis by optical emission spectrometry
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Impedancje i składowe prądu zaburzeń w obwodach z łącznikami półprzewodnikowymi = Impedances and disturbance current components in the circuits with semiconductor switches
PublikacjaW referacie przedstawiono pewien sposób określenia impedancji i składowych prądu zaburzeń dla przypadku obwodu z łącznikiem półprzewodnikowym. Określono widmową impedancje obciążenia i impedancje wewnętrzną źródła oraz rozpływy składowych prądu zaburzeń. Zaprezentowano wyniki obliczeń dla pewnego przypadku obwodu. W wnioskach omówiono wpływ przyjętego układu zastępczego źródła zaburzeń oraz częstotliwości charakterystycznej na...
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Wykorzystanie modelu silnika indukcyjnego klatkowego do prądowej diagnostyki jego łożysk. Application of induction machine model for current diagnostics of bearings
PublikacjaW pracy podano widmo prądu stojana dla silnika normalnego oraz wprawianego w drgania o nastawianej częstotliwości. Drgania korpusu wirnika skutkują uginaniem się wirnika, co symuluje bicie wirnika od uszkodzenia łożysk. Podano też model matematyczny silnika, dopuszczający niecentryczność wirnika. Podano widmo prądu stojana przy pracy z wibracjami wirnika odwzorowującymi w pewnym przybliżeniu wibracje od uszkodzonych łożysk.
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Subjective and Objective Quality Evaluation Study of BPL -PLC Wired Medium
PublikacjaThis paper presents results of research on the effectiveness of bi-directional voice transmission in a 6 kV mine cable network using BPL-PLC (Broadband over Power Line - Power Line Communication) technology. It concerns both emergency cable state (supply outage with cable shorted at both ends) and loaded with distorted current waveforms. The narrowband (0.5 MHz–15 MHz) and broadband (two different modes, frequency range of 3 MHz–7.5...
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A Wind Energy Conversion System Based on a Generator with Modulated Magnetic Flux
PublikacjaIn this work, the concept of an energy conversion system for wind turbines based on the modified permanent magnet synchronous generator (PMSG) is presented. In the generator, a pair of three-phase windings is used, one of which is connected in a “star” and the second in a “delta” configuration. At the outputs of both windings, two six-pulse uncontrolled (diode) rectifiers are included. These rectifiers are mutually coupled by a...
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A Power-Efficient Digital Technique for Gain and Offset Correction in Slope ADCs
PublikacjaIn this brief, a power-efficient digital technique for gain and offset correction in slope analog-to-digital converters (ADCs) has been proposed. The technique is especially useful for imaging arrays with massively parallel image acquisition where simultaneous compensation of dark signal non-uniformity (DSNU) as well as photo-response non-uniformity (PRNU) is critical. The presented approach is based on stopping the ADC clock by...
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Lamp of adjustable spectrum for photographic usage
PublikacjaPhotography is a unique rapidly growing interdisciplinary field encompassing aspects of science, art and technology. Expectations of photographers are steadily increasing with the development of technology. One of the areas playing a crucial role in photography is lighting. Consequently, several types of light sources for photographic use have been developed. The ongoing research in this field concentrates on lamps with tunable...
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Excitation-independent constant conductance isfet driver
PublikacjaA new constant conductance driver for ISFETs sensors has been developed. The proposed circuit maintains the sensor operating point at constant drain-source conductance. The combination of a simple, self-balancing resistance bridge and the subtraction half (or similar fraction) of source-drain voltage from the gate-source voltage provides the independence of output signal from current and voltage drivers instability. The use of...
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Control system for contactless electrical energy transfer with varying air gap
PublikacjaInductive power transfer (IPT) is a system by which electrical energy may be transmitted without electrical connection through a large air gap between coils. Systems usually considered in the literature are the ones with a constant air gap. The paper describes the analysis of IPT, which allows for supplying an electrical load in the conditions of slow, in relation to the dynamics of power supply, changes in the dimensions of the...
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Niskonapięciowy filtr analogowy CMOS wykorzystujący konwerter ujemnoimpedancyjny
PublikacjaA low-voltage 3-order low-pass CMOS filter based on the novel current inversion type negative impedance converter (CNIC) is presented. It shows a badwidth of 10 MHz at 400 uW power consumption and 2 V supply voltage when realized in a 0.35 um CMOS process.
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Niskonapięciowy filtr analogowy CMOS oparty o konwerter ujemno-impedancyjny
PublikacjaA low-voltage 3-order low-pass CMOS filter based on the novel current inversion type negative impedance converter (CNIC) is presented. It shows a badwidth of 10 MHz at 400 uW power consumption and 2 V supply voltage when realized in a 0.35 um CMOS process.
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Direct-Ultrasonic Assisted Microextraction Coupled with RTL-GC-FID/GC-MS as a Future Standard Procedure for Monitoring 26 potentially Allergenic Fragrances in Water Samples
PublikacjaThis research topic grew up as a result of awareness of constant anthropogenic and natural input to the environment constituents of personal care products (PCPs) residues. This group of emerging pollutants encompasses a wide range of chemicals, including potentially allergenic fragrance compounds. The aim of the present study was to investigate presence of 26 fragrance allergens in water samples. Simple and rapid methodology based...
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Determination of eight artificial sweeteners and common Stevia rebaudiana glycosides in non-alcoholic and alcoholic beverages by reversed-phase liquid chromatography coupled with tandem mass spectrometry.
PublikacjaThe method for the determination of acesulfame-K, saccharine, cyclamate, aspartame, sucralose, alitame, neohesperidin dihydrochalcone, neotame and five common steviol glycosides (rebaudioside A, rebaudioside C, steviol, steviolbioside and stevioside) in soft and alcoholic beverages was developed using high-performance liquid chromatography and tandem mass spectrometry with electrospray ionisation (HPLC-ESI-MS/MS). To the best of...