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Wyniki wyszukiwania dla: EQUIVALENT CIRCUIT MODELLING
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Analiza temperatury ekwiwalentnej do projektowania nawierzchni asfaltowych w Polsce z wykorzystaniem metody AASHTO 2004
PublikacjaW artykule przedstawiono analizę temperatury ekwiwalentnej obliczanej w oparciu o kryterium spękań zmęczeniowych warstw asfaltowych z metody AASHTO 2004 oraz kryterium deformacji strukturalnych Instytutu Asfaltowego. Do obliczeń przyjęto konstrukcję nawierzchni KR5 oraz wykorzystano dane temperaturowe z 50 stacji meteorologicznych z okresu 30 lat od roku 1989 do roku 2019 włącznie udostępnione przez Instytut Meteorologii i Gospodarki...
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Modelling and optimisation of MXene-derived TiO2/Ti3C2 synthesis parameters using Response Surface Methodology based on the Box–Behnken factorial design. Enhanced carbamazepine degradation by the Cu-modified TiO2/Ti3C2 photocatalyst
PublikacjaIn the present study, a hydrothermal method in a water/ethanol environment was used for the first time to obtain novel Cu/TiO2/Ti3C2 composites with high photocatalytic activity for the degradation of carbamazepine (CBZ) under simulated solar light. The Box–Behnken factorial design was coupled with Response Surface Methodology (RSM) for synthesis parameter optimisation. The effect of different synthesis parameters, including temperature, time...
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Dynamiczne wyznaczanie parametrów elektrycznego obwodu szeregowego
PublikacjaPo załączeniu napięcia na skutek istnienia inercji prąd w obwodzie zaczyna narastać od wartości zerowej do znamionowej. W tym czasie narastają spadki napięć na rezystancjach (impedancjach obwodu) do chwili spełnienia prawa Kirchhoffa. Można utworzyć układ ze sprzężeniem zwrotnym (układ regulacji stałowartościowej bądź nadążnej), który poszukuje parametrów obwodu spełniających prawa Kirchhoffa – elementy nie muszą być liniowe. W...
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A filter bank solution for active power filter control algorithms
PublikacjaThb paper describes the proposed active power fiIter (APF) with a new control circuit based on an algorithm using ufilter bank and a harmonic predictor. The conirol circuit was realized using the digiiaI signor processor ADSP-21065L and FPGA circuiL In the proposed circuit transient performunee of APF is improved The active power fdter circuil has been built and teste6 and some illustrative, experimental results are uIso presented...
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Fault Loop Impedance Measurement in Circuits Fed by UPS and Principle of Safety Protection
PublikacjaThis paper indicates a significant problem of uncertainty of fault loop impedance (FLI) measurement in circuits powered from uninterruptible power supply (UPS) (double-conversion AC-DC-AC). The correctly determined value of this impedance, related to the short-circuit current disconnection time and to the reference value, is one of the most important elements that determines the approval of an electrical installation and its receivers...
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Photovoltaic effect in the single-junction DBP/PTCBI organic system under low intensity of monochromatic light
PublikacjaPhotoelectric properties of the planar ITO/MoO3/DBP/PTCBI/BCP/Ag system were characterized on the basis of short-circuit current, open-circuit voltage and absorption spectra, and current-voltage measurements in the dark and under monochromatic illumination of low intensity. Photovoltaic performance of the system was compared with the performance of ideal semiconductor and excitonic cells of chosen bandgaps. Such analysis shows,...
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Remarks on the Subject of Back-Up Protection of Residual Current Devices
PublikacjaResidual current devices without integral overcurrent protection (RCCBs) are back-up protected by fuses or miniature circuit-breakers (MCBs). If the latter are used, special attention must be given to the coordination between an RCCB and an MCB. This paper indicates probable cases of the aforementioned devices coordination, in which back-up protection of the RCCB is not adequate. A laboratory test has shown that depending on the...
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Effective Permeability of Multi Air Gap Ferrite Core 3-Phase Medium Frequency Transformer in Isolated DC-DC Converters
PublikacjaThe magnetizing inductance of the medium frequency transformer (MFT) impacts the performance of the isolated dc-dc power converters. The ferrite material is considered for high power transformers but it requires an assembly of type “I” cores resulting in a multi air gap structure of the magnetic core. The authors claim that the multiple air gaps are randomly distributed and that the average air gap length is unpredictable at the...
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A testing method of analog parts of mixed-signal electronic systems equipped with the IEEE1149.1 test bus
PublikacjaA new solution of the JTAG BIST for testing analog circuits in mixed-signal electronic microsystems controlled by microcontrollers and equipped with the IEEE1149.1 bus is presented. It is based on a new fault diagnosis method in which an analog circuit is stimulated by a buffered signal from the TMS line, and the time response of the circuit to this signal is sampled by the ADC equipped with the JTAG. The method can be used for...
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Canonical switched capacitor converters. Comments, complements, and refinements
PublikacjaSwitched Capacitor Converters (SCC) form useful blocks in low/medium power applications as they are suitable for integration, both as off-chip and on-chip IC realizations. However, the problem with SCC is that their voltage conversion ratio is topology-dependent. By changing the SC circuit configuration, we can gain control over voltage conversion but the available ratio remains of a discrete nature, i.e. it maps into a countable...
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Case studies of resonance phenomena in high voltage overhead power lines with shunt reactors
PublikacjaMisguided design of the towers of power transmission lines can lead to serious problems such as voltage asymmetry, overvoltages, electric arc extinction difficulties or resonance – in case of double circuit line with shunt reactors. The paper points out those threats on example of 400 kV double circuit overhead transmission line with shunt reactors.
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Suitability study of hybrid model of electrodynamic actuator
PublikacjaThis paper presents the proposal of the hybrid circuit-field model of an electrodynamic actuator. The field model uses the inductor current as the input data which is obtained from the circuit model or experimentally. The field model implemented using the FLUX program makes it possible to easily determine the pressure distribution acting on the disc. The results have been verified experimentally.
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Numerical Test for Stability Evaluation of Analog Circuits
PublikacjaIn this contribution, a new numerical test for the stability evaluation of analog circuits is presented. Usually, if an analog circuit is unstable then the roots of its characteristic equation are localized on the right half-plane of the Laplace s- plane. Because this region is unbounded, we employ the bilinear transformation to map it into the unit disc on the complex plane. Hence, the existence of any root inside the unit disc...
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A structure and design optimization of novel compact microscrip dual-band rat-race coupler with enhanced bandwidth
PublikacjaIn the letter, a topology of a novel compact wideband dual-band rat-race coupler has been presented along with its computationally efficient design optimization procedure. Reduction of the circuit size has been achieved by meandering transmission lines of the conventional circuit. At the same time, the number of independent geometry parameters has been increased so as to secure sufficient flexibility of the circuit, necessary in...
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Modeling of the internal combustion engine cooling system
PublikacjaThe article concerns computer modelling of processes in cooling systems of internal combustion engines. Modelling objectives and existing commercial programs are presented. It also describes Author’s own method of binding graphs used to describe phenomena in the cooling system of a spark ignition engine. The own model has been verified by tests on the engine dynamometer. An example of using a commercial program for experimental...
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Validation of atmospheric aerosols parallel sampling in a multifold device
PublikacjaIn this work, particulate matter was collected using an active sampling system consisting of a PM10 (<10 μm) inlet coupled to a multifold device containing six channels, connected to a vacuum pump. Each channel was equipped with a filter holder fitted with adequately chosen filters. The system was fixed on a metallic structure, which was placed on the roof of the laboratory building, at the Faculty of Sciences, in Lisbon. Sampling...
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Idiosyncratic risk and cross-section of stock returns in emerging European markets
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The cross section of international government bond returns
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Investor confidence and high financial literacy jointly shape investments in risky assets
PublikacjaHouseholds consistently invest less in equities and bonds than predicted by economic theory. We explain this from a behavioral economics perspective and distributional analysis using rich US survey microdata. We find that higher investor self-confidence in her financial abilities and financial literacy jointly increase the probability of investing in equities. Conditional on participation, confidence in the macroeconomy additionally...
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Early warning models against bankruptcy risk for Central European and Latin American enterprises
PublikacjaThis article is devoted to the issue of forecasting the bankruptcy risk of enterprises in Latin America and Central Europe. The author has used statistical and soft computing methods to program the prediction models. It compares the effectiveness of twelve different early warningmodels for forecasting the bankruptcy risk of companies. In the research conducted, the author used data on 185 companies listed on the Warsaw Stock Exchange...
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Systems, environments, and soliton rate equations: A non-Kolmogorovian framework for population dynamics
PublikacjaSoliton rate equations are based on non-Kolmogorovian models of probability and naturally include autocatalytic processes. The formalism is not widely known but has great unexplored potential for applications to systems interacting with environments. Beginning with links of contextuality to non- Kolmogorovity we introduce the general formalism of soliton rate equations and work out explicit examples of subsystems interacting with...
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Quantum structure in competing lizard communities
PublikacjaAlmost two decades of research on applications of the mathematical formalism of quantum theory as a modeling tool in domains different from the micro-world has given rise to many successful applications in situations related to human behavior and thought, more specifically in cognitive processes of decision-making and the ways concepts are combined into sentences. In this article, we extend this approach to animal behavior, showing...
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Export diversification and dependence on natural resources
PublikacjaLow export diversification is a risk-augmenting factor for many countries dependent on natural resources. The literature tends to focus on the growth effects of resource dependence (‘resource curse’ debate) while not much is known on how it affects the variety of non-resource exports. To quantify this effect we decompose the relative Theil index using product-level export data from 160 countries over the time period 1996–2018....
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Możliwości modelowania rozkładu naprężeń i odkształceń w endoprotezie stawu biodrowego w układzie implant - kość z uwzględnieniem własności materiałowych = Possibility of stress and strain modelling in total hip replacement in implant-bone system including material properties
PublikacjaW pracy przedstawiono możliwości wykorzystania numerycznych technik komputerowych do modelowania rozkładu naprężeń i odkształceń w endoprotezie stawu biodrowego w układzie implant-kość z uwzględnieniem własności materiałowych elementów endoprotezy. Przedstawiono komputerowe modele służące do analizy naprężeń i odkształceń w endoprotezie wykonane przy wykorzystaniu metody elementów skończonych. Metody modelowania naprężeń i odkształceń...
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Low cost electrochemical sensor module for measurement of gas concentration
PublikacjaThis paper describes a low cost electrochemical sensor module for gas concentration measurement. A module is universal and can be used for many types of electrochemical gas sensors. Device is based on AVR ATmega8 microcontroller. As signal processing circuit a specialized integrated circuit LMP9l000 is used. The proposed equipment will be used as a component of electronic nose system employed for classifying and distinguishing...
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Earth wires currents calculation by tableau analysis
PublikacjaThe paper presents a new method to compute a phase-to-earth fault current distribution in overhead transmission line. The method is based on the tableau analysis of an unbalanced, multi-wire model of a transmission line. It allows for the calculation of current distribution in overhead earth wires along the transmission line. Additionally, it may be used to calculate currents in a tower’s earthing system as well as voltages over...
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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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Composite shells in 6-field nonlinear shell theory
PublikacjaW pracy przedstawiono równanie konstytutywne uwzględniające wielowarstwowość materiału powłoki. Równania wyprowadzono bazując na podejściu Equivalent Single Layer
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Przegląd i analiza układów napędowych stosowanych w rowerach elektrycznych
PublikacjaStreszczenie ang. : The purpose of his article is an overview and analysis of the drive system used in electrical bikes. Classical and modern drive system are described. The stress is putted on the electrical motors used in that applications. Structure, control and power supply of most recent design are presented. The analysis applies to hub motor type Clyte 408 used as a bike drive. Authors have decided to build a filed-circuit...
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On Design Optimization of Miniaturized Microscrip Dual-Band Rat-Race Coupler with Enhanced Bandwidth
PublikacjaIn the paper, a novel topology of a miniaturized wideband dual-band rat-race coupler has been presented. Small size of the circuit has been obtained by meandering transmission lines of the conventional circuit. At the same time, the number of independent geometry parameters has been increased in order to secure sufficient circuit flexibility in the context of its design optimization for dual-band operation. Optimum dimensions of...
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Modeling of Combined Phenomena Affecting an AUV Stealth Vehicle
PublikacjaIn the paper some results of research connected with modelling the basic stealth characteristics of an AUV vehicle are presented. First of all a general approach to design of the stealth AUV autonomous underwater vehicle under consideration is introduced. Then, the AUV stealth vehicle concept is briefly described. Next a method of modelling of the stealth characteristics is briefly described as well. As an example of the stealth...
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approximation of photonic crystal fibres with large air holes by the step index fibre model
PublikacjaAn equivalent step index fibre with a silica core and air cladding is used to model photonic crystal fibres with large air holes. We model this fibre for linear polarisation (we focus on the lowest few transverse modes of the electromagnetic field). The equivalent step index radius is obtained by equating the lowest two eigenvalues of the model to those calculated numerically for the photonic crystal fibres. The step index parameters...
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Numerical modelling of POC dynamics in the southern Baltic under possible future conditions determined by nutrients, light and temperature**The study was financially supported by the Polish Ministry of Science and Higher Education (grants: NN305 111636 and NN306 404338) and Baltic-C – the BONUS funded project.
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Programmable feedforward linearized CMOS OTA for fully differential continuous-time filter design
PublikacjaW artykule przedstawiono metodę linearyzacji wzmacniacza transkonduktancyjnego (OTA) CMOS z zastosowaniem sprzężenia w przód. Wzmacniacz zbudowany jest z użyciem prostych par różnicowych, wzmacniacza w pętli sprzężenia zwrotnego do samoregulacji transkonduktancji wzmacniaczy oraz liniowej rezystancji odniesienia (R). W wyniku uzyskano znaczną linaryzację charakterystyk przejściowych wzmacniacza OTA. Symulacje komputerowe SPICE...
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Hybrid‐mode single‐slope ADC with improved linearity and reduced conversion time for CMOS image sensors
PublikacjaIn the paper, a single‐slope analog‐to‐digital converter (ADC) for integrated CMOS image sensor applications with an improved technique of conversion has been proposed. The proposed hybrid‐mode ADC automatically uses one of the following conversion techniques: time based (i.e. PWM) or voltage based (i.e. single‐slope). During the ADC operation, the clock frequency and reference voltage are modified in order to reduce the conversion...
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A general approach to continuous time Gm-C filters.
PublikacjaW pracy zaproponowano ogólną strukturę filtrów Gm-C z odpowiednim opisem macierzowym. W odniesieniu do tej struktury podano formuły analizy wrażliwościowej dla dowolnego filtru Gm-C czasu ciągłego. Analiza oparta na opisie macierzowym była wykorzystana również do porównania właściwości filtrów Gm-Ctrybu napięciowego i prądowego. Zdefiniowano dwie kanoniczne transformacje dla klasy filtrów zmiennych stanu.
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Application of spatial neural simulators of turbine blade rows to fluid flow diagnostics
PublikacjaThis chapter presents the results of neural modelling of fluid flow in steam turbine row. In modelling working conditions of the flow channel varied, thus the aim of the work was to reconstruct the reference state - distributions of velocity, pressure, and losses in flow channel - with high accuracy for fluid flow diagnostics.
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Response features for fast EM-driven design of miniaturized impedance matching transformers
PublikacjaA framework for low-cost EM-driven design optimization of compact impedance matching transformers is presented. Our technique is based on a bottom-up design where design requirements for the transformer circuit are translated into specifications for its building blocks. These elementary cells are optimized using response features. Subsequently, the entire circuit is fine-tuned using local response surface approximation models and...
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Thermal-FSI modeling of flow and heat transfer in a heat exchangerbased on minichanels
PublikacjaIn this paper selected numerical modelling problems for an advanced thermal-FSI ("Fluid Solid Interaction") mini-channel heat exchanger model are presented. Special attention is given to the heat transfer between the separated mediums for different mass flows. Similar modelling problems have also been discussed in the literature dedicated to numerical and theoretical modelling problems for typical heat exchangers [1, 2, 3]. Basic...
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A review on analytical models of brushless permanent magnet machines
PublikacjaThis study provides an in-depth investigation of the use of analytical and numerical methods in analyzing electrical machines. Although numerical models such as the finite-element method (FEM) can handle complex geometries and saturation effects, they have significant computational burdens, are time-consuming, and are inflexible when it comes to changing machine geometries or input values. Analytical models based on magnetic equivalent...
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Warunek zwarciowy SkQ/Sn>=20 ograniczeniem rozwoju OZE
PublikacjaW referacie omówiono zagadnienia związane z warunkiem zwarciowym, czyli ilorazem mocy zwarciowej w rozpatrywanym miejscu przyłączenia do sieci elektroenergetycznej źródła energii i mocy znamionowej tego źródła. Wskazano jego pochodzenie oraz przedyskutowano zasadność jego stosowania w analizach przyłączeniowych.
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Designing Control and Protection Systems with Regard to Integrated Functional Safety and Cybersecurity Aspects
PublikacjaThis article addresses current problems of risk analysis and probabilistic modelling for functional safety management in the life cycle of safety-related systems. Two main stages in the lifecycle of these systems are distinguished, namely the design and operation. The risk analysis and probabilistic modelling differ in these stages in view of available knowledge and data. Due to the complexity and uncertainty involved, both qualitative...
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Mainstream shortcut N removal modeling current status and perspectives
PublikacjaThis work gives an overview of the state-of-the-art in modelling of short-cut processes for nitrogen removal in mainstream wastewater treatment and presents future perspectives for directing research efforts in line with the needs of practice. The modelling status for deammonification (i.e., anammox-based) and nitrite-shunt processes is presented with its challenges and limitations. The importance of mathematical models for considering...
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Between Descriptive Geometry and CAD 3D
PublikacjaDescriptive geometry provides methods to analyse three-dimensional space through two-dimensional drawings and prepares to create technical documentation. Geometric form of an engineering project is presented by the means of projection methods based on a 3D model, which is present in designer’s imagination. The forthcoming era of Building Information Modelling (BIM) brings changes in the way the engineer works, as the vision is...
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Implementation of power transformer controlled switching algorithm
PublikacjaThe article presents two new algorithms of controlled switching the power transformer. The main aim of the paper is to obtain formulas that determine the moments of closing of the circuit breaker poles. The study contains projects of control systems for both algorithms. Mathematical formulas for the time instants of the breaker poles closing were developed on the basis of electric circuit theory and magnetic circuit theory. The...
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Amyloid fibril formation in the presence of water structure-affecting solutes
PublikacjaThe impact of the differently hydrated non-electrolytes (protein structure destabilizers) on the fibrillation of hen egg white lysozyme (HEWL) was investigated. Two isomeric urea derivatives i.e. butylurea (BU) and N,N,N′,N′-tetramethylurea (TMU) were chosen as a tested compounds. The obtained results show that butylurea exerts greater impact on HEWL and its fibrillation than tetramethylurea. Both substances decrease the time of...
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Weak forms of shadowing in topological dynamics
PublikacjaWe consider continuous maps of compact metric spaces. It is proved that every pseudotrajectory with sufficiently small errors contains a subsequence of positive density that is point-wise close to a subsequence of an exact trajectory with the same indices. Also, we study homeomor- phisms such that any pseudotrajectory can be shadowed by a finite number of exact orbits. In terms of numerical methods this property (we call it multishadowing)...
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Why do Poles withdraw from the labour market so early? - systematics of the factors influencing Poles' decisions to retire
PublikacjaThe study undertakes to identify the factors that influence the decisions of the working population approaching retirement age to withdraw from the labour market (which in this case is equivalent to retirement) or continue economic activity (also after reaching the formal retirement age)
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Modele numeryczne uwzględniające tarczową pracę pokrycia dachowego z blach trapezowych
PublikacjaW artykule porównano wybrane sposoby uwzględniania w modelowaniu numerycznym tarczowej pracy pokrycia dachowego z blachy trapezowej, możliwe do zrealizowania w programie Autodesk Robot Structural Analysis Professional 2015, w celu oceny słuszności stosowania ich do obliczeń konstrukcji nośnej współpracującej z poszyciem z blachy trapezowej. Analizy przeprowadzono dla pojedynczej przepony. Za pomocą powłokowych elementów skończonych...
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Multiple output second-generation current conveyor utilizing high frequency output stage
PublikacjaIn this paper a multiple output second-generation current conveyor (MOCCII) is presented. The main advantage of the proposed general circuit architecture over a typical structure, well known in the literature, is the use of a high passband multiple output current mplifier block instead of cascaded current mirrors. It gives similar frequency responses for all the outputs of the current conveyor and also maintains simplicity of the...