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Wyniki wyszukiwania dla: EXPERIMENTAL SPECTRA
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Photoluminescence of partially reduced Eu2+/Eu3+ active centers in a NaF–Al2O3–P2O5 glassy matrix with tunable smooth spectra
PublikacjaIn this work, a series of photoluminescent materials have been synthesized based on optically transparent and chemically stable glasses of the nominal composition Na3Al2(PO4)2F3 (NaF–Al2O3–P2O5 system) doped with 1 wt% of europium. It has been shown that the synthesis conditions (mainly the temperature and duration of the melting stage under reducing conditions) strongly affected the photoluminescence spectra of the material. This...
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Electronic States of Tris(bipyridine) Ruthenium(II) Complexes in Neat Solid Films Investigated by Electroabsorption Spectroscopy
PublikacjaWe present the electric field-induced absorption (electroabsorption, EA) spectra of the solid neat films of tris(bipyridine) Ru(II) complexes, which were recently functionalized in our group as photosensitizers in dye-sensitized solar cells, and we compare them with the results obtained for an archetypal [Ru(bpy)3]2+ ion (RBY). We argue that it is difficult to establish a unique set of molecular parameter values by discrete parametrization...
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Synthesis and Characterization of Monometallic (Ag, Cu) and Bimetallic Ag-Cu Particles for Antibacterial and Antifungal Applications
PublikacjaIn this paper, the experimental studies are concerned with the effect of the synthesis parameters on the formation of monometallic Ag and Cu nanoparticles (NPs). We consider the synthesis strategies verification for the bimetallic core-shell and alloy particles preparation. It was successfully obtained by chemical reduction method. The obtained colloidal solution is characterized by the transmission electron microscopy (TEM) with...
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Electromagnetic interference frequencies prediction model of flyback converter for snubber design
PublikacjaSnubber design for flyback converters usually requires experimental prototype measurements or simulation based on accurate and complex models. In this study simplified circuit modelling of a flyback converter has been described to dimension snubbers in early stage of design process. Simulation based prediction of the transistor and diode ringing frequencies has been validated by measurements in a prototype setup. In that way obtained...
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On small signal capacitance spectra of organic diode formed by ITO-palladium phthalocyanine-Al sandwich system
PublikacjaPraca poświęcona jest widmom małosygnalowej pojemności w zakresie 25 Hz-1 MHz i charakterystyce prądowo-napięciowej planarnego układu utworzonego przez ITO/ftalocyanina palladu/Al.
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Anomalous diffraction approximation to the light scattering coefficient spectra of marine particles with power-law size distribution
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Least Squares Estimators of Peptide Species Concentrations Based on Gaussian Mixture Decompositions of Protein Mass Spectra
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Configurational assignment of vic-amino alcohols from their circular dichroism spectra with dirhodium tetracetate as an auxiliary chromophore
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Vibrational spectroscopic studies of N,N'-dimethylpropyleneurea-water system: Affected solvent spectra and factor analysis
PublikacjaZmierzono widma FT-IR układu N,N'-dimetylopropylenomocznik (DMPU) - woda w całym zakresie składów w zakresie 4000-500 cm-1 przy użyciu techniki całkowitego wewnętrznego odbicia (ATR). Hydratacja DMPU została dodatkowo zbadana przy pomocy transmisyjnej spektroskopii FT-IR izotopowo rozcieńczonej HDO w H2O. Widma zanalizowano przy użyciu ilościowej wersji metody widm różnicowych, prowadzącej do wyizolowania widma rozpuszczalnika...
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Data analysis of FTIR spectra for study of outlet gases of Solid Oxide Fuel Cells fuelled by biogas
PublikacjaW pracy przedstawiono system umożliwiający połączenie spektroskopii FTIR z specjalnie zaprojektowanym oprogramowaniem w celu uzyskania informacji o stężeniach gazów wylotowych z ogniw paliwowych SOFC. Przebadane zostały główne produkty reformingu biogazu: tlenek węgla, dwutlenek węgla, metan oraz wodór. Opisane oprogramowanie umożliwia w prosty i szybki sposób uzyskanie informacji o gazach wylotowych ogniwa paliwowego.
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Spontaneous generation of chirality and chiroptical spectra of N-nitroso-2,4-diaryl-3-azabicyclo[3.3.1]nonanes
PublikacjaBadane związki o szkielecie 2,4-diarylo-3-azabicyclo[3.3.1]nonanów krystalizują w chiralnej grupie przestrzennej jako konglomeraty, co oznacza że uzyskane, makroskopowej wielkości kryształy można rozdzielić manualnie na dwie grupy zgodnie z asymetrią ich powierzchni. Homochiralne kryształy wybranych enancjomerów zsyntetyzowanych związków poddano badaniom rentgenostrukturalnym oraz zarejestrowano ich widma CD i UV-vis. Konfigurację...
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Teoretyczny opis metody pomiaru chwilowego widma impedancyjnego. Theoretical description of the measuring of instantenous impedance spectra
PublikacjaPrzedstawiony został teoretyczny opis wyznaczania chwilowego widma impedancyjnego. Połączenie szumu pseudo-białego oraz metody krótkoczasowej transformacji Fouriera pozwala na wyznaczenie zmian widma impedancyjnego w funkcji czasu. Teoretyczne podstawy nowej metody pomiarowej wskazują na możliwość zastosowania jej do procesów niestacjonarnych.
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Effect of electrode resistance on admittance spectra of planar organic device carrying SCLC and on charge carrier mobility extracted from susceptance
PublikacjaThe work presents small signal admittance spectra of a sandwich system with thin organic layer carrying a space charge limited current. The effect of series resistance of electrodes on the spectra is discussed. Spectra of small signal capacitance are added to get more detailed insight. The analysis performed shows that the series resistance can affect both parts of small signal response within a whole range of frequency. Moreover,...
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Anharmonic Infrared Spectroscopy through the Fourier Transform of Time Correlation Function Formalism in ONETEP
PublikacjaDensity functional theory molecular dynamics (DFT-MD) provides an efficient framework for accurately computing several types of spectra. The major benefit of DFTMD approaches lies in the ability to naturally take into account the effects of temperature and anharmonicity, without having to introduce any ad hoc or a posteriori corrections. Consequently, computational spectroscopy based on DFT-MD approaches plays a pivotal role in...
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Effect of shallow traps on admittance spectra of the system carrying SCLC and on values of charge carrier mobility extracted from susceptance
PublikacjaThe work concerns small-signal spectra of space-charge-limited current below threshold frequency (ft) of shallow traps. It is shown that below ft the small-signal concentration of trapped charge carriers is proportional to and in phase with small-signal concentration of free charge carriers, so there is no room for “slow shallow traps”. Conductance can be reduced by the traps, however no change in the range of real capacitance...
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Waterborne polyesters partially based on renewable resources
PublikacjaA new experimental approach for preparing biobased, water-soluble polyesters via titanium(IV) n-butoxide-catalyzed bulk polycondensation is presented. In the described method polymers were obtained from isosorbide, maleic anhydride and poly(ethylene glycol). The chemical structure of the synthesized polyesters was confirmed using 2D NMR spectroscopy and by titration methods. Careful analysis of 2D NMR spectra viz. Correlation Spectra...
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The use of fast molecular descriptors and artificial neural networks approach in organochlorine compounds electron ionization mass spectra classification
PublikacjaDeveloping of theoretical tools can be very helpful for supporting new pollutant detection. Nowadays, a combination of mass spectrometry and chromatographic techniques are the most basic environmental monitoring methods. In this paper, two organochlorine compound mass spectra classification systems were proposed. The classification models were developed within the framework of artificial neural networks (ANNs) and fast 1D and...
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The influence of intermolecular correlations on the infrared spectrum of liquid dimethyl sulfoxide
PublikacjaDimethyl sulfoxide (DMSO) is routinely applied as an excellent, water-miscible solvent and chemical reagent. Some of the most important data concerning its liquid structure were obtained using infrared (IR) spectroscopy. However, the actual extent of intermolecular correlations that connect the isolated monomer spectrum to the IR response of the bulk liquid is poorly studied thus far. Using ab initio molecular dynamics (AIMD) simulations,...
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Chemometric determination of solute-affected solvent vibrational spectra as a superior way of information extraction on solute solvation phenomena
PublikacjaW pracy zaprezentowano dwie chemometryczne metody wyznaczania widm zaburzonych rozpuszczalnika oraz liczby cząsteczek zaburzonych, na podstawie zmierzonych serii wibracyjnych widm FT-IR roztworów substancji. Pierwsza z metod została stworzona na podstawie Namiarowej Analizy Faktorowej (ang. Target Factor Analysis). Druga z nich wykorzystuje algorytm izolacji widm czystych składników z serii widm mieszanin. Działanie obu metod zostało...
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Extraction of mass spectra free of background and neighboring component contributions from gas chromatography/mass spectrometry data
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Theoretical Modeling of High-Resolution X-ray Spectra Emitted by Tungsten and Molybdenum Ions from Tokamak Plasmas
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Measurements of high-temperature emission spectra of highly irradiated LiF:Mg,Cu,P (MCP-N) TL detectors
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Ab initio study of phenyl benzoate: structure, conformational analysis, dipole moment, IR and Raman vibrational spectra
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Density Functional Theory Studies on Ir Spectra of the Triphenylene Derivatives. A Scaled Quantum Mechanical Force Field Approach
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Small signal spectra of complex capacitance obtained on organic heterojunction formed from copper phthalocyanine and perylene dye
PublikacjaPraca przedstawia małosygnałowe widma zespolonej pojemności otrzymane na strukturze z heterozłączem organicznym CuPc/Py-PTC w zakresie 25Hz-1MHz.
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Unique agreement of experimental and computational infrared spectroscopy: a case study of lithium bromide solvation in an important electrochemical solvent
PublikacjaInfrared (IR) spectroscopy is a widely used and invaluable tool in the studies of solvation phenomena in electrolyte solutions. Using state-of-the-art chemometric analysis of a spectral series measured in a concentration-dependent manner, the spectrum of the solute-affected solvent can be extracted, providing a detailed view of the structural and energetic states of the solvent molecules influenced by the solute. Concurrently,...
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FIBRE-OPTIC SENSOR FOR SIMULTANEOUS MEASUREMENT OF THICKNESSAND REFRACTIVE INDEX OF LIQUID LAYERS
PublikacjaIn this paper, we present a fibre-optic sensor for simultaneous measurement of refractive index and thickness of liquid layers. We designed an experimental low-coherence setup with two broadband light sources and an extrinsic fibre-optic Fabry–Pérot interferometer acting as the sensing head. We examined how the refractive index of a liquid film and its thickness affect spectrum at the output of a fibre-optic interferometer. We...
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Electric transport in organic system with planar DBP/F16ZnPc junction on the basis of direct current and small signal admittance spectra analysis
PublikacjaThe objective of this work was to determine electric transport in the organic device based on a planar junction of electron donor and electron acceptor materials, namely ITO/MoO3/DBP/F16ZnPc/BCP/Ag. The analysis reported herein was based on direct current-voltage measurements and small-signal admittance spectra in the dark and under illumination. Such analysis may provide information on potential barriers, parasitic resistances...
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Molecular level interpretation of excess infrared spectroscopy
PublikacjaInfrared (IR) spectroscopy is an invaluable tool in studying intermolecular interactions in solvent mixtures. The deviation of the IR spectrum of a mixture from the spectra of its pure components is a sensitive measure of the non-ideality of solutions and the modulation of intermolecular interactions introduced by mutual influence of the components. Excess IR spectroscopy, based on the established notion of excess thermodynamic...
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Unraveling the origin of the complex structure of the thorium Lγ x-ray lines in high-resolution spectra induced by heavy projectiles
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Dimolybdenum Tetraacetate as an Auxiliary Chromophore in Absolute Configuration Determination of Amino Acids from their Circular Dichroism Spectra - Foundations and Developments
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A Novel Ru(II) Polypyridine Black Dye Investigated by Resonance Raman Spectroscopy and TDDFT Calculations
PublikacjaThe optical properties of a new(bipyridine)2Ru(4H-imidazole) complex presenting a remarkablebroad absorption in the visible range are investigated. Thestrong overlap of the absorption with the solar radiationspectrum renders the studied complex promising as a blackabsorber and hence as a starting structure for applications inthe field of dye-sensitized solar cells. The correlations betweenstructural and electronic features for...
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An effective method for studying intermolecular interactions in binary liquids with hydrogen bonds: FTIR spectra and ab initio calculations in the N-methylformamide - methanol system
PublikacjaMolecular complexes in methanol (MeOH)−N-methylformamide (NMF) mixtures were studied based on their FTIR-ATR spectra, to which two methods of analysis were applied: factor analysis and a quantitative version of the difference-spectra method. The mean composition of a complex between NMF and MeOH molecules over the whole range of mixture compositions was determined. Absorbing species differentiated with regard to the interaction...
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Electron interactions with Bis(pentamethylcyclopentadienyl) titanium(IV) dichloride and difluoride
PublikacjaWe present a combined experimental and theoretical study of the interaction of electrons with Bis(pentamethylcyclopentadienyl)titanium(IV) dichloride (Cp∗2TiCl2) and difluoride (Cp∗2TiF2). We report the experimental measurements of partial cross sections for the dissociative electron attachment (DEA) and the electron ionization (EI) mass spectra of isolated molecules. Estimates of the absolute cross sections are done on the basis...
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Color prediction from first principle quantum chemistry computations: a case of alizarin dissolved in methanol
PublikacjaThe electronic spectrum of alizarin (AZ) in methanol solution was measured and used as reference data for color prediction. The visible part of the spectrum was modelled by different DFT functionals within the TD-DFT framework. The results of a broad range of functionals applied for theoretical spectrum prediction were compared against experimental data by a direct color comparison. The tristimulus model of color expressed in terms...
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Electrical properties of hybrid planar diode based on palladium phthalocyanine and titanium dioxide
PublikacjaThis work details experimental studies of a planar diode made of indium tin oxide/titanium dioxide/palladium phthalocyanine/gold. The rectification ratio of current was 105 at 1.5 V. The analysis of the electrical properties of the system was based on small signal complex capacitance spectra measured in the frequency range of 25 Hz-1 MHz at different values of bias. No depletion region at the TiO2/PdPc interface was observed. Forward...
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Experimental study on models of cylindrical steel tanks under mining tremors and moderate earthquakes
PublikacjaThe aim of the study is to show the results of complex shaking table experimental investigation focused on the response of two models of cylindrical steel tanks under mining tremors and moderate earthquakes, including the aspects of diagnosis of structural damage. Firstly, the impact and the sweep-sine tests have been carried out, so as to determine the dynamic properties of models filled with different levels of liquid. Then,...
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Reprezentatywne dla danego języka spektra odpowiedzi impulsowej kanału głosowego [Language specific spectra generated in the human vocal tract]
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Structure of single KL0–, double KL1–, and triple KL2 − ionization in Mg, Al, and Si targets induced by photons, and their absorption spectra
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Induction machine behavioral modeling for prediction of EMI propagation.
PublikacjaThis paper presents the results of wideband behavioral modeling of an induction machine (IM). The proposed solution enables modeling the IM differential- and common-mode impedance for a frequency range from 1 kHz to 10 MHz. Methods of parameter extraction are derived from the measured IM impedances. The developed models of 1.5 kW and 7.5 kW induction machines are designed using the Saber Sketch scheme editor and simulated in the...
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Surface modification of PMMA polymer and its composites with PC61BM fullerene derivative using an atmospheric pressure microwave argon plasma sheet
PublikacjaThis paper presents the results of experimental investigations of the plasma surface modification of a poly(methyl methacrylate) (PMMA) polymer and PMMA composites with a [6,6]-phenyl-C61-butyric acid methyl ester fullerene derivative (PC61BM). An atmospheric pressure microwave (2.45 GHz) argon plasma sheet was used. The experimental parameters were: an argon (Ar) flow rate (up to 20 NL/min), microwave power (up to 530 W), number...
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Spin-Resolved Band Structure of Hoffman Clathrate [Fe(pz)2Pt(CN)4] as an Essential Tool to Predict Optical Spectra of Metal–Organic Frameworks
PublikacjaParamount spin-crossover properties of the 3D-Hoffman metalorganic framework (MOF) [Fe(pz)2Pt(CN)4] are generally described on the basis of the ligand field theory, which provides adequate insight into theoretical and simulation analysis of spintronic complexes. However, the ligand field approximation does not take into account the 3D periodicity of the actual complex lattice and surface effects and therefore cannot predict a full-scale...
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Local Dye Concentration and Spectroscopic Properties of Monomer−Aggregate Systems in Hybrid Porous Nanolayers
PublikacjaAnalysis of absorption, fluorescence, and time-resolved emission spectra of rhodamine 6G in hybrid porous nanolayers at high dye concentration allowed identification of two fluorescent species: monomers and fluorescent aggregates. The method of determination of mean local concentration of aggregates in matrices is proposed based on the energy transfer process between monomers and fluorescent aggregates. Evaluation of aggregate...
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Sum-over-state expressions including second-order Herzberg–Teller effects for the calculation of absorption and resonance Raman intensities
PublikacjaThe sum-over-state expressions are derived to calculate the second-order Herzberg–Teller (HT) effects in absorption and resonance Raman spectroscopies. These effects depend on the second derivatives of the transition dipole moment with respect to the vibrational coordinates. The method is applied to the molecule of 1,3-butadiene using density functional theory calculations. It is found that the second-order HT effects are significant...
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Effect of osmolytes of different type on DNA behavior in aqueous solution. Experimental and theoretical studies
PublikacjaOsmolytes, the small organic molecules accumulated in cells under environmental stress, can modulate the stability of biopolymers such as proteins and DNA. In spite of many years of research, there is no established molecular mechanism of the influence of osmolytes on DNA structure. Here, we used two model osmolytes that denature (urea) or stabilize (trimethylglycine, TMG) proteins to study their effect on DNA in aqueous solutions...
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Quantitative assessment of the main antioxidant compounds, antioxidant activities and FTIR spectra from commonly consumed fruits, compared to standard kiwi fruit
PublikacjaBioactive compounds (polyphenols and ascorbic acid) and dietary fibers, and related antioxidant activities of commonly consumed apples, bananas, peaches, pears, blond and red grapefruits, pomelos, oranges, lemons, red plums, white grapes, mango, persimmon and strawberries grown in the same geographical and climatic conditions were compared with standard kiwi fruit. The presence of polyphenols was studied by Fourier transform infrared...
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Enantiomeric Resolution of N,N'-Dimethyldithiodianthranilide through Diastereomeric silver(I) complex. Chiroptical spectra, racemization barrier and molecular self-assembly
PublikacjaN,N'-dimetyloditiodiantranilid, związek o chiralności płaszczyznowej, rozdzielono na enancjomery. Optycznie czynne molekuły uzyskano w wyniku tworzenia chiralnego kompleksu N,N'-dimetyloditiodiantranilidu z solą srebrową kwasu (1S)-kamforosulfonowego. W oparciu o badania rentgenostrukturalne monokryształu uzyskanego kompleksu określono absolutną konfigurację przykoordynowanego ligandu jako (R). Enancjomery N,N'-dimetyloditiodiantranilid...
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Unusual fluorescence anisotropy spectra of three-component donor-mediator-acceptor systems in uniaxially stretched polymer films in the presence of energy transfer
PublikacjaW pracy analizowano transfer energii w układzie donor-mediator-akceptor w osiowo rozciąganych foliach polimerowych. Stwierdzono, że informacja zawarta w orientacji wektora pola elektrycznego wiązki światła wzbudzającego układ jest zachowana po zajściu procesu transferu energii pomiędzy molekułami w foliach rozciąganych. Natomiast w foliach nierozciąganych fluorescencja mediatora i akceptora jest bardzo silnie zdepolaryzowana.
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DMSO and TMAO—Differences in Interactions in Aqueous Solutions of the K-Peptide
PublikacjaInteractions between a solvent and their co-solute molecules in solutions of peptides are crucial for their stability and structure. The K-peptide is a synthetic fragment of a larger hen egg white lysozyme protein that is believed to be able to aggregate into amyloid structures. In this study, a complex experimental and theoretical approach is applied to study systems comprising the peptide, water, and two co-solutes: trimethylamide...
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Charge Transfer, Complexes Formation and Furan Fragmentation Induced by Collisions with Low-Energy Helium Cations
PublikacjaThe present work focuses on unraveling the collisional processes leading to the fragmentation of the gas-phase furan molecules under the He+ and He2+ cations impact in the energy range 5–2000 eV. The presence of different mechanisms was identified by the analysis of the optical fragmentation spectra measured using the collision-induced emission spectroscopy (CIES) in conjunction with the ab initio calculations. The measurements of...