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Wyniki wyszukiwania dla: power spectral density
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Diagnostic testing of marine propulsion systems with internal combustion engines by means of vibration measurement and results analysis
PublikacjaIn this paper selected issues concerning vibration diagnosis of the mechanical system within marine propulsion units have been presented, carried out on the basis of experimental examinations of a real object in which an exceedance of the allowable vibration’s level had been observed. Used diagnosing system has been characterised. A procedure of longitudinal and transverse vibrations shaft lines of the mechanical system within...
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Method of Monitoring of the Grinding Process with Lapping Kinematics Using Audible Sound Analysis
PublikacjaUtilising microphones as audible sound sensors for monitoring a single-side grinding process with lapping kinematics is presented in the paper. The audible sound generated during grinding depended on the cutting properties of electroplated tools with D107 diamond grains and different thicknesses of the nickel bond. The tool wear affected the obtained technological effects such as material removal rate and the surface roughness...
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A dual-control strategy based on electrode material and electrolyte optimization to construct an asymmetric supercapacitor with high energy density
PublikacjaMetal-organic frames (MOFs) are regarded as excellent candidates for supercapacitors that have attracted much attention because of their diversity, adjustability and porosity. However, both poor structural stability in aqueous alkaline electrolytes and the low electrical conductivity of MOF materials constrain their practical implementation in supercapacitors. In this study, bimetallic CoNi-MOF were synthesized to enhance the electrical...
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Correlated Particle Motion and THz Spectral Response of Supercritical Water
PublikacjaMolecular dynamics simulations of supercritical water reveal distinctly different distance-dependent modulations of dipolar response and correlations in particle motion compared to ambient conditions. The strongly perturbed H-bond network of water at supercritical conditions allows for considerable translationaland rotational freedom of individual molecules. These changes give rise to substantially different infrared spectra and...
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Room temperature depinning of the charge-density waves in quasi-two-dimensional 1T-TaS2 devices
PublikacjaWe report on the depinning of nearly commensurate charge-density waves in 1T-TaS2 thin films at room temperature. A combination of the differential current–voltage measurements with the low-frequency noise spectroscopy provides unambiguous means for detecting the depinning threshold field in quasi-2D materials. The depinning process in 1T-TaS2 is not accompanied by an observable abrupt increase in electric current—in striking contrast...
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Methodology for implementing power plant efficiency standards for power generation: potential emission reduction
PublikacjaSome methods of generating power such as power generation through coal, natural gas, oil result in inevitable emissions of greenhouse gases. While power generation is necessary due to its increasing demand, it is important for power companies to generate their power in an efcient manner to reduce its efect on the environment. One of the most efective ways of tackling inefciency issues is through the implementation of efciency standard....
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Correlation between charge density waves and antiferromagnetism in Nd1−xGdxNiC2 solid solutions
PublikacjaWe report a study on the evolution of a charge density wave and antiferromagnetism in the series of the polycrystalline solid solution Nd1−xGdxNiC2 (0 _ x _ 1) by means of magnetic and transport properties measurements. The experimental results reveal the violation of the de Gennes law and a strong correlation between the Peierls, Néel, and Curie-Weiss temperatures, which strongly suggests a cooperative interaction between the...
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Giant Nernst effect in the incommensurate charge density wave state of P4W12O44
PublikacjaWe report the study of Nernst effect in quasi-low-dimensional tungsten bronze P4W12O44 showing a sequence of Peierls instabilities. We demonstrate that both condensation of the electronic carriers in the charge density wave state and the existence of high-mobility electrons and holes originating from the small pockets remaining in the incompletely nested Fermi surface give rise to a Nernst effect of a magnitude similar to that...
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Hydro Power Plant in the Process of Voltage Control in the Electric Power System and the System Restoration
PublikacjaThe article covers selected issues related to the share of hydroelectric power in the process of rebuilding the power system after black-out and voltage control during that process. Selected results of measurements made during the creation of the transmission chain for the need to start a block of a thermal power plant from a hydroelectric power plant were presented.
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Voltage and Reactive Power Load Flow Optimization in the Power System Using Fuzzy Logic
PublikacjaThe paper presents issues related to voltage control in the power system. An original method of reactive power flow optimization is considered, which leads to improved voltages in the power system and reduced active power losses. The optimization method is based on a procedure that employs fuzzy logic and is supported by a gradient search algorithm. The method has been implemented in PLANS software and verified.
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Modular power converter topologies for energy storage and electric power distribution systems
PublikacjaThis paper describes selected issues concerning realization of energy storage system (ESS) designed to operate in power distribution system. In order to achieve scalability of the system a modular approach is proposed. In addition to this different configuration of the system are analyzed, where depending on requirements and application a scalability in power, in energy capacity of energy storage resource and both in power and...
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The Conley index and spectral sequences
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Modelling of the Heat Flux Density Distribution for Laser Beam Welding
PublikacjaGreat interest of the laser beam welding in industry is a new theoretical task, making planning the welding procedure specification and the quality control of welded joints easier. Estimating and calculating the dimensions of a weld pool and temperature distribution near weld mainly concern heat source modelling. In the presented work calculations of welding pool shape and thermal field for cylindrical-powered-normally model of...
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PROCESSING, MECHANICAL AND THERMAL PROPERTIES OF RECYCLED LOW-DENSITY POLYETHYLENE STREAMS
PublikacjaThe recycling of plastics is currently one of the most significant industrial challenges. Due to the enormous amounts of plastic wastes generated by various industry branches, it is essential to look for the potential methods of their utilization. Nevertheless, for the efficient application of recycled materials it is crucial to analyze their performance. Therefore, in presented paper we investigated the processing (melt flow index),...
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Interactions between hydration spheres of two different solutes in solution: The least squares fitting with constraints as a tool to determine water properties in ternary systems
PublikacjaBiological systems are complex and the problem of their description lies in mutual interactions between their components. This paper is focused on model experiment-based studies which can reduce these difficulties. The ternary aqueous N-methylacetamide (NMA)–Na2HPO4 system has been studied by means of the FTIR spectroscopy. A novel difference spectra method aimed to extract the spectral contribution of water affected simultaneously...
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Roughness evaluation of turned composite surfaces by analysis of the shape of Autocorrelation Function
PublikacjaIn this paper, the application of an Autocorrelation Function for the characterisation of surface topography was validated. The roughness evaluation of turned composite surfaces was supported by sophisticated studies of the Autocorrelation Function properties, considering especially the shape of the function. Details were measured with the optical method. The selection of the surface roughness evaluation procedures was carried...
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Temperature Coefficient of Electronic Polarizability in Thin Polymer Films Deposited on Si and SiO2 Substrates Determined via Spectroscopic Ellipsometry
PublikacjaEllipsometry is widely used to determine the thermo-optical properties of thin polymer films. However, if the thermo-optic coefficient (TOC) and the linear thermal expansion coefficient (LTEC) are to be used to determine the temperature coefficient of electronic polarizability (TCEP) in thin polymer films, their values must be determined with the greatest possible accuracy, as both have the opposite effect. In this article,...
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Direct brain stimulation modulates encoding states and memory performance in humans
PublikacjaPeople often forget information because they fail to effectively encode it. Here, we test the hypothesis that targeted electrical stimulation can modulate neural encoding states and subsequent memory outcomes. Using recordings from neurosurgical epilepsy patients with intracranially implanted electrodes, we trained multivariate classifiers to discriminate spectral activity during learning that predicted remembering from forgetting,...
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UAV Design and Construction for Real Time Photogrammetry and Visual Navigation
PublikacjaA unmanned aerial vehicles applications in photogrammetry have increased rapidly last years. A fast data gathering and processing in real time in some cases become crucial and desired in some application. In the paper, a real time solution is proposed. A real time photogrammetry from UAV is proposed, where image data are gathered and processed on board UAV and finally reconstructed 3D model and measurements are delivered. The paper...
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Enhancing electrochemical properties of an ITO-coated lossy-mode resonance optical fiber sensor by electrodeposition of PEDOT:PSS
PublikacjaA sensor working in multiple domains may offer enhanced information about the properties of an investigated analyte, including those containing biological species. It has already been shown that a dual-domain sensing capability, i.e., in optical and electrochemical domains, can be offered by lossy-mode resonance (LMR) sensors based on indium-tin-oxide (ITO) thin film. The spectral response of the LMR sensors depends on the refractive...
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Minute and diverse in fossil sticky stuff: Tanytarsini (Diptera: Chironomidae) from early Eocene Indian Cambay amber
PublikacjaWe here present a pioneering systematic review of fossil dipterans of the tribe Tanytarsini (family Chironomidae) discovered in Indian amber from Cambay. The specimens examined belong to five species: Gujaratomyia miripes, Stempellina stebneri sp. nov., Stempellinella pollex sp. nov., Tanytarsus forfex sp. nov. and Tanytarsus ramus sp. nov., which are described. All species belong to the oldest known Tanytarsini and come from the...
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Data Acquisition and Processing for GeoAI Models to Support Sustainable Agricultural Practices
PublikacjaThere are growing opportunities to leverage new technologies and data sources to address global problems related to sustainability, climate change, and biodiversity loss. The emerging discipline of GeoAI resulting from the convergence of AI and Geospatial science (Geo-AI) is enabling the possibility to harness the increasingly available open Earth Observation data collected from different constellations of satellites and sensors...
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Mechanism of Osmolyte Stabilization–Destabilization of Proteins: Experimental Evidence
PublikacjaIn this work, we investigated the influence of stabilizing (N,N,N-trimethylglycine) and destabilizing (urea) osmolytes on the hydration spheres of biomacromolecules in folded forms (trpzip-1 peptide and hen egg white lysozyme─hewl) and unfolded protein models (glycine─GLY and N-methylglycine─NMG) by means of infrared spectroscopy. GLY and NMG were clearly limited as minimal models for unfolded proteins and should be treated with...
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Multiple sound sources localization in free field using acoustic vector sensor
PublikacjaMethod and preliminary results of multiple sound sources localization in free field using the acoustic vector sensor were presented in this study. Direction of arrival (DOA) for considered source was determined based on sound intensity method supported by Fourier analysis. Obtained spectrum components for considered signal allowed to determine the DOA value for the particular frequency independently. The accuracy of the developed...
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Anatomy of noise in quantitative biological Raman spectroscopy
PublikacjaRaman spectroscopy is a fundamental form of molecular spectroscopy that is widely used to investigate structures and properties of molecules using their vibrational transitions. It relies on inelastic scattering of monochromatic laser light irradiating the specimen. After appropriate filtering the scattered light is dispersed onto a detector to determine the shift from the excitation wavelength, which appears in the form of...
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Low-Cost Behavioral Modeling of Antennas by Dimensionality Reduction and Domain Confinement
PublikacjaBehavioral modeling has been rising in importance in modern antenna design. It is primarily employed to diminish the computational cost of procedures involving massive full-wave electromagnetic (EM) simulations. Cheaper alternative offer surrogate models, yet, setting up data-driven surrogates is impeded by, among others, the curse of dimensionality. This article introduces a novel approach to reduced-cost surrogate modeling of...
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The differential impact of a density of Polish pine wood on cutting forces with its origin region taken into consideration
PublikacjaIn the article the dependence of cutting forces in a function the density of wood with regard to the wood origin are presented. Samples used in experiment were with Scotch pine (Pinus sylvestris L.) originating from four provenances in Poland (Figure 1). Wood density was measured by two methods: stereometric method (global density) and radiometric method (local density). Stereometric method consists in measurements the volume...
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IEEE TRANSACTIONS ON POWER ELECTRONICS
Czasopisma -
A novel approach to energy safety improvement in the marine power plants with active power surge compensator
PublikacjaPaper raises a point of power surges and theirs adverse effects in the marine power plants. The article explains a source of surges appearance, and presents measurements carried out on a modern ship. It discusses effects of dynamic power transients on the ship’s energy safety. Finally it proposes, a novel approach for power surge elimination, based on medium voltage active conditioner. As well as it propose the topology and control...
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Interfacial adhesion evaluation in (low-density polyethylene)/elastomer blends
PublikacjaLow-density polyethylene (LDPE) with different elastomers at a ratio of 50/50 wt% blends was prepared by using a co-rotating twin-screw extruder. Three kinds of elastomers were used: ground tire rubber (GTR), partially crosslinked butyl rubber (KalarVR ), and styrenebutadiene- rubber block copolymer (SBS; KratonVR ). For better characterization of interaction between polyethylene and elastomer, influence of the type of elastomer on...
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Measurements of active power coefficients in a ship power station with two generators working in parallel
Dane BadawczeThe presented dataset is part of research focusing on the assessment of metrological properties of the instrument, Estimator/Analyzer (E/A v.2), developed and made at the Faculty of Electrical Engineering, Department of Marine Electrical Power Engineering of Gdynia Maritime University. The attached dataset contains processed data, expressing active...
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Measurements of active power distribution in a ship power station with two generators working in parallel
Dane BadawczeThe presented dataset is part of research focusing on the assessment of metrological properties of the instrument, Estimator/Analyzer (E/A v.2), developed and made at the Faculty of Electrical Engineering, Department of Marine Electrical Power Engineering of Gdynia Maritime University. The attached dataset contains processed data expressing an active...
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Measurements of reactive power distribution in a ship power station with two generators working in parallel
Dane BadawczeThe presented dataset is part of research focusing on the assessment of metrological properties of the instrument, Estimator/Analyzer (E/A v.2), developed and made at the Faculty of Electrical Engineering, Department of Marine Electrical Power Engineering of Gdynia Maritime University. The attached dataset contains processed data, expressing a reactive...
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Influence of the Spectral Quality of Light on Daytime Alertness Levels in Humans
PublikacjaExposure to light is very important for human health. However, the characteristics of the light stimulus and the appropriate timing of such exposure are essential. Studies that have used monochromatic light exposure have shown no systematic patterns for the effects of blue light compared to longer wavelengths. Previous studies have shown that red light exposure increases objective and subjective measures of alertness at night without...
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Start-up of a power unit of a thermal power plant auxiliary systems with supply from a hydropower plant
PublikacjaThis article discusses the issues related to a power unit of a thermal power plant start-up with the use of a hydropower plant. Hydropower plant can supply and will enable start-up of auxiliary equipment in a power unit of a thermal power plant. Due to high capacity of auxiliary drives, start-up of auxiliaries in a thermal power plant after blackout (and boiler shutdown) is not possible from emergency energy sources in the power...
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A Quantitative Investigation of Dislocation Density in an Al Matrix Composite Produced by a Combination of Micro-/Macro-Rolling
PublikacjaAn aluminum matrix composite with dispersed carbon nanotubes (CNTs) was produced via flake powder metallurgy using a micro-rolling process and vacuum hot pressing (VHP), followed by conventional rolling using a macro-rolling process. The microstructure and mechanical properties of the produced composites were studied. In addition, a new quantitative model was introduced to study the dislocation density based on the microstructural...
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On power stream in motor or drive system
PublikacjaIn a motor or in a drive system the quantity of power increases in the direction opposite to the direction of power flow. Energy losses and energy efficiency of a motor or a drive system must be presented as functions of physical quantities independent of losses. Such quantities are speed and load. But the picture of power stream in a motor or in a drive system is presented in the literature in the form of traditional Sankey...
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Solutions of Power Electronics Converter for the Shore - to - Ship Power Systems
PublikacjaW artykule poruszono tematykę zasilania statków zacumowanych w porcie z lądowej sieci elektroenergetycznej poprzez wykorzystanie nowoczesnych konstrukcji przekształtników energoelektronicznych. Zaproponowano budowę sieci dystrybucyjnej prądu stałego, przewoźnej platformy zasilającej oraz zastosowanie zasobników energii
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Measurement cell - current density analysis.
PublikacjaW pracy przedstawiono model celki do pomiarów elektrycznych parametrów szkliwa i innych tkanek zęba. Wyniki otrzymano za pomocą metody elementu skończonego. Wykazano, że możliwa do osiągnięcia dokładność pomiaru jest zdeterminowana przez prąd upływu celki.
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Active Power Quality Controllers
PublikacjaDynamic Static Synchronous Compensator is the most important controller for distribution networks and probably in SEEN. It has been widely used since the 1990s to regulate system voltage precisely, improve voltage profile, reduce voltage harmonics, reduce transient voltage disturbances and load compensation. Rather than using conventional capacitors and inductors combined with fast switches, the D-STATCOM uses a power-electronics...
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INCREASING POWER SUPPLY SAFETY IN THE ASPECT OF SUPPORTING THE RENEWABLE ENERGY SOURCES BY CONVENTIONAL AND VIRTUAL POWER STORES
PublikacjaThis paper presents characteristics and purposefulness of supporting the renewable energy sources (OZE) by means of energy stores. The main emphasis was placed on analysis of virtual energy stores available for implementation in Polish economy conditions. A role which management of Demand Side Response (DSR) may play in balancing Polish electric power system, is discussed. Implementation of such solutions together with conventional...
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Rotational Molding of Linear Low-Density Polyethylene Composites Filled with Wheat Bran
PublikacjaApplication of lignocellulosic fillers in the manufacturing of wood polymer composites (WPCs) is a very popular trend of research, however it is still rarely observed in the case of rotational molding. The present study aimed to analyze the impact of wheat bran content (from 2.5 wt.% to 20 wt.%) on the performance of rotationally-molded composites based on a linear low-density polyethylene (LLDPE) matrix. Microscopic structure...
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Charge density wave and crystalline electric field effects in TmNiC2
PublikacjaSingle crystals of TmNiC2 were grown by the optical floating-zone technique and were investigated by x-ray diffraction (XRD), thermal expansion, electrical resistivity, specific heat, and magnetic susceptibility measurements. Single-crystal XRD reveals the formation of a commensurate charge density wave (CDW) characterized by a CDW modulation vector q2c = (0.5, 0.5, 0.5), which is accompanied by a symmetry change from the orthorhombic...
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Modular power converter with superconducting magnetic energy storage for electric power distribution system — Analysis and simulation
PublikacjaThis paper describes selected issues concerning realization of energy storage system (ESS) designed to operate in power distribution system. This paper presents a modular approach of 300 kVA power converter operating with superconducting magnetic energy storage (SMES), which gives high dynamics together with high power and suitable capability for instantaneous energy storage. Analysis and simulation studies of selected power converter...
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Power equalization of AES FPGA implementation
PublikacjaThis paper briefly introduces side channel attacks on cryptographic hardware with special emphasis on differential power analysis(DPA). Based on existing countermeasures against DPA, design method combining power equalization for synchronous and combinatorialcircuits has been proposed. AES algorithm has been implemented in Xilinx Spartan II-E field programmable gate array (FPGA) deviceusing the standard and power-equalized methods....
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Measurements of apparent power distribution in a ship power station with two generators working in parallel
Dane BadawczeThe presented dataset is part of research focusing on the assessment of metrological properties of the instrument, Estimator/Analyzer (E/A v.2), developed and made at the Faculty of Electrical Engineering, Department of Marine Electrical Power Engineering of Gdynia Maritime University. The attached dataset contains processed data, expressing an apparent...
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EMI mitigation of GaN power inverter leg by local shielding techniques
PublikacjaThis paper presents local shielding techniques applied to a half-bridge inverter leg with the aim to reduce the common mode (CM) current noise at converter’s DC input. The research study is conducted for 650V Enhancement mode Gallium Nitride (GaN) power transistor switches. Main contributors of parasitic capacitances referred to the inverter-leg middle point node are identified. Then, shielding solutions are proposed to reduce...
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Power balance in hydraulic satellite motors supplied with oil and HFA-E emulsion
PublikacjaMineral oil and HFA-E emulsion are liquids which differ in viscosity, density and lubricant properties. Therefore, supplying hydraulic satellite motors with these liquids, differences between quantity of hydraulic, volumetric and mechanical losses are observed. These losses influence efficiency of conversion of hydraulic energy into mechanical energy and thereby power balance of motors.
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Activity coordination of capacitor banks and power transformer controllers in order to reduce power losses in the MV grid
PublikacjaOne of the main issues related to the optimization of the MV (middle voltage) network is to reduce losses of active and reactive power. Lower losses of active and reactive power give not only economic advantage, but also improvement of energy quality. The object of regulation that can be used for these purposes are transformer with On-Load Tap Changer and capacitor's banks. This paper presents results of analysis of the possibility...
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Ab initio and density functional theory calculations of proton affinities for volatile organic compounds
PublikacjaThe Hatree-Fock method with 6-311G** split-valence molecular orbitals basis sets and the density function theory-B3LYP have been applied to geometrical optimizations and calculations of total electronic, zero point vibrational energies and proton affinities at 298 K for volatile organic compounds. Calculated values of proton affinities are compared with experimental data.