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Search results for: LARGE-SCALE DFT
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Ab-initio study of electrical and optical properties of allylamine
PublicationThe Density functional theory is one of most promising methodology in fast and accurate calculations of electrical and optical properties from the atomic basis. In this paper, we calculate electrical and optical properties of allylamine (2-propen 1- amine) in terms of accuracy and speed of calculations obtained by selection of DFT-1/2 method with ultrasoft Vanderbilt pseudopotentials. Comparison of density of states between molecule...
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SZTUKA WIZUALNA W OBIEKTACH MEDYCZNYCH = VISUAL ARTS IN MEDICAL FACILITIES
PublicationWspółczesna architektura obiektów służby zdrowia podlega dynamicznym przeobrażeniom formalnym wynikającym zarówno z rozwoju technologii medycznych, zmian zachodzących w podejściu wobec pacjenta. Narastający w naukach medycznych kierunek holistyczny ustawia pacjenta jako użytkownika w trzech wymiarach: biologicznym, społecznym i psychologicznym. Stąd pojawiające się w procesie projektowym dotyczącym szpitali czy przychodni nowe...
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Innowacja urbanistyczna w kontekście kształtowania środowiska mieszkaniowego
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Inrush and short circuit current identification based on real-time spectral analysis with the use of the FPGA FFT processor
PublicationW artykule przedstawiono krótkookresową analize widmową prądu załączeniowego i prądu zwarciowego transformatora w czasie rzeczywistym z zastosowaniem procesora FFT zrealizowanego w FPGA. Otrzymane widmo ułatwia rozróżnienie rodzaju prądu, co może być zastosowanei do lepszego sterowania zabezpieczneiem różnicowo-prądowym. Określono tez teoretyczne przebiegi prądów dla przyjetego modelu transformatora. Przeprowadzono ponadto analizę...
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Using A Particular Sampling Method for Impedance Measurement
PublicationThe paper presents an impedance measurement method using a particular sampling method which is an alternative to DFT calculation. The method uses a sine excitation signal and sampling response signals proportional to current flowing through and voltage across the measured impedance. The object impedance is calculated without using Fourier transform. The method was first evaluated in MATLAB by means of simulation. The method was...
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Sulfurization of phosphanylphosphinidene ligand: Access to phosphinothioyltrithiophosphonato platinum(II) complexes
PublicationThe reactivity of phosphanylphosphinidene Pt(0) complexes [DppePt(η2-P–PtBu2)] (1) and [(pTol3P)2Pt(η2-P–PtBu2)] (2) toward sulfur was studied. Reactions of 1 and 2 with an excess of sulfur led to the formation of the first transition metal complexes 3 and 4 with phosphinothioyltrithiophosphonato ligands with the formula [tBu2P(=S)–P(=S)S2]2-. In contrast to previous reports on the phosphanylphosphinidene moiety sulfurization,...
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The Reactivity of the Imine Bond within Polynuclear Nickel(II) Complexes
PublicationThree novel Ni complexes with the Schiff base ligand 2-methoxy-6-(E-2-pyridyliminomethyl)-phenol (L1) are described. In comparison with the similar 2-(pyridine-2-ylimino-methyl)phenol (pymp), the mode of coordination of L1 is altered due to the presence of methoxy substituent introducing the sterical hindrance. During the synthesis of the complexes, partial hydrolysis of the ligand was observed. Since such immediate hydrolysis...
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Metody projektowania ułatwiającego testowanie dla układów cyfrowych
PublicationPrzedstawiono przegląd metod ułatwiających testowanie DFT (Design for Testability) dla układów cyfrowych. Zaprezentowano metody stosowane na poziomie układów scalonych, pakietów oraz systemów elektronicznych. Pokazano heurystyczne metody projektowania pozwalające na zwiększenie sterowalności i obserwowalności układów oraz metody strukturalne, a wśród nich układy BILBO (Built-In Logic Block Observer), BIST (Built-In Self Test),...
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Exploring thiophene-2-acetate and thiophene-3-acetate binding modes towards the molecular and supramolecular structures and photoluminescence properties of Pb(ii) polymers
PublicationTo evaluate the impact of the flexible positional isomeric ligands thiophene-2-acetate (2tpacCOO) andthiophene-3-acetate (3tpacCOO) on the construction and self-assembly process of Pb(II) polymers, twonovel compounds, [Pb(2tpacCOO)2(H2O)]n(1) and [Pb(3tpacCOO)2]n(2), were preparedviaanonhydro-thermal method with respect to green chemistry rules. The obtained polymers were fully characterized byelemental analysis, TG/DTG and PXRD,...
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Electronic structure calculations in electrolyte solutions: Methods for neutralization of extended charged interfaces
PublicationDensity functional theory (DFT) is often used for simulating extended materials such as infinite crystals or surfaces, under periodic boundary conditions (PBCs). In such calculations, when the simulation cell has non-zero charge, electrical neutrality has to be imposed, and this is often done via a uniform background charge of opposite sign (“jellium”). This artificial neutralization does not occur in reality, where a different...
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Large Animal Review
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In situ transformation boosts the pseudocapacitance of CuNi-MOF via cooperative orientational and electronic governing
PublicationThe disordered arrangement and thereof inferior conductivity of 2D MOF sheets seriously hinder their practical application. Herein, we propose in situ transformation strategy to architect vertically oriented bimetallic CuNi-MOF as a self-supporting electrode, leading to a decuple high specific capacitance of 1262 C g-1 in comparison with the pristine Ni-MOF powder of 114 C g-1 at 2 A g-1. DFT calculations reveal that introduction...
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On thio‐substituted N‐heterocyclic arsines
PublicationMetathesis of N-heterocyclic chloroarsines with sulfur-based nucleophiles furnished thio-substituted 1,3,2-diazarsolidines and 1,3,2-diazarsolenes. Crystallographic and NMR spectroscopic studies revealed that a thiocyanato-diazarsolene exhibits a salt-like structure composed of weakly interacting thiocyanate and arsenium ions, while the remaining products formed neutral molecules. The structural data indicate that the heterocyclic...
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Synthesis and characterization of mononuclear Zn(II), Co(II) and Ni(II) complexes containing a sterically demanding silanethiolate ligand derived from tris(2,6-diisopropylphenoxy)silanethiol
PublicationFour heteroleptic complexes of zinc(II), cobalt(II) and nickel(II) containing a monodentate silanethiolate ligand derived from tris(2,6-diisopropylphenoxy)silanethiol (TDST), were prepared and characterized. The geometries of ligands in the complexes are typical: distorted tetrahedral in zinc and cobalt(II) complexes and square planar in nickel(II) compound. Magnetic studies performed for Ni(II) and Co(II) compounds confirm the...
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DFT studies of the refractive index of boron-doped diamond
PublicationThe density functional theory is one of the optimal solutions in calculation of optical properties of materials on the quantum scale. In this paper, we have investigated the refractive index of a boron-doped diamond structure with the usage of Atomistic Toolkit software from Synopsys. During this study, various methods and pseudopotentials were checked to obtain an optimal performanceaccuracy method for calculation of such materials....
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Optymalizacja zasobów chmury obliczeniowej z wykorzystaniem inteligentnych agentów w zdalnym nauczaniu
PublicationRozprawa dotyczy optymalizacji zasobów chmury obliczeniowej, w której zastosowano inteligentne agenty w zdalnym nauczaniu. Zagadnienie jest istotne w edukacji, gdzie wykorzystuje się nowoczesne technologie, takie jak Internet Rzeczy, rozszerzoną i wirtualną rzeczywistość oraz deep learning w środowisku chmury obliczeniowej. Zagadnienie jest istotne również w sytuacji, gdy pandemia wymusza stosowanie zdalnego nauczania na dużą skalę...
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Compressible gas density measurement by means of Fourier analysis of interferograms
PublicationThis paper describes a method for nonintrusive compressible gas density measurement by means of automated analysis of interferograms using FFT (Fast Fourier Transform), and its implementation using DFT (Discrete Fourier Transform), that does make this measurement technique a fairly valuable and accessible experimental method. The presented approach makes it possible to use the finite fringe setting of the interferometer, thus reducing...
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Self-testing of analog parts of mixed-signal electronic microsystems based on multiple sampling of time responses
PublicationW artykule przedstawiono nowe podejście samo-testowania toru analogowego zakończonego przetwornikiem A/C w mieszanych sygnałowo elektronicznych systemach wbudowanych sterowanych mikrokontrolerami. Bazuje ono na nowej metodzie diagnostycznej opartej na przekształceniu transformującym zbiór próbek odpowiedzi czasowej układu badanego na pobudzenie impulsem prostokątnym na rodzinę krzywych identyfikacyjnych umieszczonych w przestrzeni...
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Optimization of Hydrogen - Evolving Photochemical Molecular Devices
PublicationA molecular photocatalyst consisting of a RuII photocenter, a tetrapyridophenazine bridging ligand, and a PtX2 (X=Cl or I) moiety as the catalytic center functions as a stable system for light-driven hydrogen production. The catalytic activity of this photochemical molecular device (PMD) is significantly enhanced by exchanging the terminal chlorides at the Pt center for iodide ligands. Ultrafast transient absorption spectroscopy...
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Stability and phase transition investigation of olanzapine polymorphs
PublicationWe use electrical embedded-fragment QM method with both DFT/ωB97XD/6-31G* and MP2/6-31G* to investigate the phase transformations of olanzapine. Gibbs free energy calculations predict that form I is always the most stable structure and form II is the least stable one, while form IV is more stable than form III below about 200 K but less stable above this temperature, implying a polymorphic phase transformation. This may account...
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Small-Scale Forestry
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SPACIAL FORM DESIGN scale 1:1
e-Learning CoursesBrief description: The subject matter of the spatial form design classes is transformation. First, a black square becomes a flat graphic composition, which is then converted to color. The final stage of the transformation process is a spatial object, which is by assumption devoid of any utilitarian functions. Course content / classes schedule: 1. Graphic. The task is to create an achromatic flat composition in the contrast...
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Large hydrodynamic thrust bearing: Comparison of the calculations and measurements
PublicationHydrodynamic thrust bearings, used to carry axial loads in heavily loaded shafts of water power plants hydro turbines, can reach outer diameters even exceeding 5 m. In such large objects scale effect could be observed. According to this, allowable bearing specific load assuring safe operation of the bearings has to be decreased, which increases thrust bearing dimensions. This effect is caused by excessive thermal deflections of...
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Relationship between electronic structure and geometry of silanethiols and their derivatives. Elucidation of copper group silanethiolates
PublicationWyznaczono strukturę elektronową wybranych silanotioli X3SiSH (dla X=H, C2H5, OCH3, F, Cl i Br) oraz powstalych z nich anionów. Geometrię i funkcje falowe wyznaczono przy użyciu teorii funcjonałów gęstości elektronowej DFT. Przeanalizowano wpływ efektów anomerycznych oraz wielkości calki nakładania sigma(Si-S) na obserwowane skrócenie wiązania Si-S przy deprotonowaniu silanotioli. Podano nowe wyjaśnienie wyjątkowo niskiej kwasowości...
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Unassisted formation of hemiaminal ether from 4-aminopyridine and o-vanillin - experimental and theoretical study
PublicationThe reactions between o-vanillin and three isomeric aminopyridines lead to imines of diverse spatial conformation and reactivity. The direct products of these simple reactions carried out in methanol are either imine compounds formed in the reactions of 2- amino- and 3-aminopyridine with o-vanillin or the α-aminoether formed in the reaction of o-vanillin with 4-aminopyridine. The Schiff-type derivative of 4-aminopyridine and o-vanillin,...
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Do positrons measure atomic and molecular diameters?
PublicationWe report on density functional calculations (DFT) of elastic integral scattering cross-sections for positron collisions with argon, krypton, nitrogen and methane. The long-range asymptotic polarization potential is described using higher-order terms going much beyond an induced dipole potential (−α / r 4) while the short-range interaction is modeled by two different forms of electron – positron correlation potential (Boroński-Nieminen...
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Protein thermal stabilization in aqueous solutions of osmolytes
PublicationProteins’ thermal stabilization is a significant problem in various biomedical, biotechnological, and technological applications. We investigated thermal stability of hen egg white lysozyme in aqueous solutions of the following stabilizing osmolytes: Glycine (GLY), N-methylglycine (NMG), N,N-dimethylglycine (DMG), N,N,N-trimethylglycine (TMG), and trimethyl-N-oxide (TMAO). Results of CD-UV spectroscopic investigation were compared...
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Prediction of Overall In Vitro Microsomal Stability of Drug Candidates Based on Molecular Modeling and Support Vector Machines. Case Study of Novel Arylpiperazines Derivatives
PublicationOther than efficacy of interaction with the molecular target, metabolic stability is the primary factor responsible for the failure or success of a compound in the drug development pipeline. The ideal drug candidate should be stable enough to reach its therapeutic site of action. Despite many recent excellent achievements in the field of computational methods supporting drug metabolism studies, a well-recognized procedure to model...
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Theoretical study of the structure, energetics and vibrational frequencies of water-acetone and water-2-butanone complexes
PublicationKompleksy acetonu i 2-butanonu z 0-2 cząsteczkami wody połączonymi wiązaniem wodorowym z tlenem karbonylowym zbadano z wykorzystaniem teorii funkcjonału gęstości (DFT) na poziomie B3LYP/6-311++G(d,p). Obliczenia w fazie gazowej uzupełniono o optymalizacje w otoczeniu rozpuszczalnika, symulowanego za pomocą modelu polaryzowalnego kontinuum (PCM). Częstości drgań oscylacyjnych otrzymane na podstawie zależności empirycznej sa zgodne...
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Carboxylation Enhances Fragmentation of Furan upon Resonant Electron Attachment
PublicationWe report a dissociative electron attachment study to 2-furoic acid (C5H4O3) isolated in a gas phase, which is a model molecule consisting of a carboxylic group and a furan ring. Dissociation of furan by low energy electrons is accessible only via electronic excited Feshbach resonances at energies of incident electrons above 5 eV. On the other hand, carboxylic acids are well- known to dissociate via attachment of electrons at subexcitation energies....
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Reactivity of bulky aminophosphanes towards small molecules: Activation of dihydrogen and carbon dioxide by aminophosphane/borane frustrated Lewis pairs
PublicationA series of mono- and bisaminophosphanes with formulas R2NPR’R’’ and (R2N)2PR’ (R = iPr, Cy; R’ = Ph, Cy; R’’ = iPr) were characterized by X-ray analysis, NMR spectroscopy and computational methods. The common structural futures of these species are short and polarized PAN bonds, a pyramidal geometry at the P atom and an almost planar geometry at the N atoms. According to DFT calculations, these...
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Mixed-ligand complexes of zinc(II), cobalt(II) and cadmium(II) with sulfur, nitrogen and oxygen ligands. Analysis of the solid state structure and solution behavior. Implications for metal ion substitution in alcohol dehydrogenase
PublicationScharakteryzowano strukturę heteroleptycznych kompleksów cynku(II), kobaltu(II) i kadmu(II) z 2-(2'-hydroksyetylopirydyną), tri-tert-butoksysilanotiolem i metanolem. Przy pomocy widm UV-Vis i NMR stwierdzono szybką wymianę N-liganda w roztworach tych kompleksów. Wyznaczono przesunięcia 15N NMR 2-(2'-hydroksyetylopirydyny) w kompleksach cynku(II) i kadmu(II). Na podstawie widm w podczerwieni i obliczeń DFT oszacowano względną moc...
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Comparison of the coordination geometries of Zn(II) and Cd(II) ions in complexes with water, methanol and bulky aryloxysilanethiolate ligands
PublicationZinc and cadmium complexes containing silanethiolate anions and methanol or water were synthesized and characterized by X-ray diffraction, FT-IR and NMR spectroscopy, and DFT calculations. Contrary to zinc, the cadmium ion utilizes very weak donors to complete its coordination sphere; it forms contacts to phenyl rings of the silanethiolate ligand. Two zinc analogs of the general formula [Zn{SSi(OAr)3}2(L)2] where L = CH3OH (2)...
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Crystal structure and electronic structure of CePt2In7
PublicationWe report a corrected crystal structure for the CePt2In7 superconductor, refined from single crystal x-ray diffraction data. The corrected crystal structure shows a different Pt–In stacking along the c-direction in this layered material than was previously reported. In addition, all of the atomic sites are fully occupied with no evidence of atom site mixing, resolving a discrepancy between the observed high resistivity ratio of...
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Large Hydrodynamic Thrust Bearings and Their Application in Hydrogenerators
PublicationLarge hydrodynamic thrust bearings are the bearings which, due to hydrodynamic lubrication, allow large axial load to be transferred from a moving part (shaft) to the stationary part via a thin layer of the lubricant (usually oil), thus providing extremely low friction and practically no wear. Hydrogenerators with vertical shafts are the most important application of large thrust bearings. Main design and scientific problems of...
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Model based evaluation of plant improvement at a large wastewater treatment plant (WWTP)
PublicationIn this work, the effect of the improvement carried out at a large-scale wastewater treatment plant (WWTP) was evaluated, by means of modelling works, with the aim to determine the influence of the modernization over the process performance. After modernization, the energy consumption due to the aeration decreased about a 20% maintaining the effluent quality. In order to double-check the good effluent quality, modelling works were...
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Aqueous solutions of NMA, Na2HPO4 , and NaH2PO4 as models for interaction studies in phosphate–protein systems
PublicationPhosphate buffers are essential for many areas of studies. However, their influence on buffered systems is often ignored. The phosphate salts can interact with biologically important macromolecules (e.g. proteins) and stabilize or destabilize them. With our research, we want to answer question what kind of interactions, if any, occur between phosphate ions and a protein backbone model — N-methylacetamide (NMA). ATR-FTIR spectroscopy...
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Ultrafast Intramolecular Relaxation and Wave-Packet Motion in a Ruthenium-Based Supramolecular Photocatalyst
PublicationThe hydrogen-evolving photocatalyst [(tbbpy)2 Ru(tpphz)Pd(Cl)2 ](2+) (tbbpy=4,4'-di-tert-butyl-2,2'-bipyridine, tpphz=tetrapyrido[3,2-a:2',3'-c:3'',2''-h:2''',3'''-j]phenazine) shows excitation-wavelength-dependent catalytic activity, which has been correlated to the localization of the initial excitation within the coordination sphere. In this contribution the excitation-wavelength dependence of the early excited-state relaxation...
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DFT modelling of the edge dislocation in 4H-SiC
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Nonlinear phenomena of small-scale sound in a gas with exponential stratification
PublicationThe nonlinear dynamics of perturbations, quickly varying in space, with comparatively large characteristic wavenumbers k: k>1/H, is considered. H is the scale of density and pressure reduction in unperturbed gas, as the coordinate (H is the so-called height of the uniform equilibrium gas). Coupling nonlinear equations which govern the sound and the entropy mode in a weakly nonlinear flow are derived. They describe the dynamics...
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Ryszard S. Romaniuk profesor
PeopleProfessor of Electronics, Computer and Communications Engineering at Warsaw University of Technology, Poland; Eisenhower Fellow, Philadelphia, MA USA; SPIE Fellow, Bellingham, WA USA; Editor-in-Chief, International Journal of Electronics and Telecommunications, Polish Academy of Sciences; Photonics Spectra Magazine, EAB Member;
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Friction and Lubrication of Large Tilting-Pad Thrust Bearings
PublicationFluid film bearings have been extensively used in the industry because of their unbeatable durability and extremely low friction coefficient, despite a very low coefficient of friction dissipation of energy being noticeable, especially in large bearings. Lubricating systems of large tilting pad thrust bearings utilized in large, vertical shaft hydrogenerators are presented in this paper. A large amount of heat is generated due...
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Experimental and theoretical studies on the photodegradation of 2-ethylhexyl 4-methoxycinnamate in the presence of reactive oxygen and chlorine species
Publication2-Ethylhexyl 4-methoxycinnamate (EHMC) is one of the most commonly used sunscreen ingredient. In this study we investigated photodegradation of EHMC in the presence of such common oxidizing and chlorinating systems as H2O2, H2O2/HCl, H2O2/UV, and H2O2/HCl/UV. Reaction products were detected by gas chromatography with a mass spectrometric detector (GC-MS). As a result of experimental studies chloro-substituted 4-methoxycinnamic...
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Hydration of Simple Carboxylic Acids from Infrared Spectra of HDOand Theoretical Calculations
PublicationBadanie hydratacji kwasów karboksylowych w rozcieńczonych roztworach wodnych ma duże znaczenie dla zrozumienia ich funkcji biologicznych. Metodą stosowaną w badaniach była spektroskopia oscylacyjna FTIR z zastosowaniem techniki rozcieńczenia izotopowego wody półciężkiej HDO w roztworze wody zwykłej. Do analizy danych widmowych wykorzystano ''metodę widm różnicowych''. Widma HDO zaburzonej przez kwasy: mrówkowy, octowy i propionowy...
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Theoretical pKa prediction of O-phosphoserine in aqueous solution
PublicationSprawdzono zdolność modelu polaryzowalnego kontinuum (PCM) do przewidywania wartości pKa w roztworze wodnym dla O-fosfoseryny (P-Ser). Obliczenia przeprowadzono w ramach teorii funkcjonału gęstości (DFT) przy użyciu funkcjonałów B3LYP i M06-2X oraz baz 6-31+G(d) and 6-31+G(d,p). Obliczenia na poziomie B3LYP/6-31+G(d,p) przy użyciu modelu solwatacji SMD zapewniają doskonałą zgodność z doświadczeniem, pod warunkiem uwzględnienia...
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Method using square-pulse excitation for high-impedance spectroscopy of anticorrosion coatings
PublicationArtykuł prezentuje metodę spektroskopii impedancyjnej przeznaczonej do diagnostyki powłok antykorozyjnych na obiektach bezpośrednio w terenie. Aby skrócić czas uzyskania widma impedancji (w zakresie od 1 mHz do 1 MHz) do kilku minut, wykorzystano sygnały harmoniczne do pomiaru widma powyżej 10 Hz a impuls prostokątny w dolnym zakresie częstotliwości. Do wyznaczania widma użyto algorytmów DSP odpowiednich do sygnału pobudzenia....
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Proton transfer and hydrogen bonds in supramolecular, self-assembled structures of imidazolium silanethiolates. X-ray, spectroscopic and theoretical studies
PublicationThe reaction of 1-methylimidazole, 2-ethyl-4-methylimidazole and 2-ethylimidazole with tris(2,6- diisopropylphenoxy)silanethiol (TDST) leads to the formation of three new salts, which have been characterized by elemental analyses, thermogravimetric analyses, FTIR spectroscopy, and their structures were determined by single-crystal X-ray diffraction. Structural analyses indicate that in all three compounds a proton transfer has...
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Local Conformation and Cocrystallization Phenomena in Renewable Diaminoisoidide-Based Polyamides Studied by FT-IR, Solid State NMR, and WAXD
PublicationBiobased polyamides synthesized from diaminoisoidide (DAII), 1,4-diaminobutane, and sebacic acid are investigated by FT-IR, 13C{1H} magic-angle spinning/cross-polarization (CP/MAS) NMR spectroscopy, and WAXD. Their molecular conformation and mobility undergo distinct changes as a function of temperature and diaminoisoidide content in the compositions. The presence of randomly distributed diaminoisoidide (DAII) in the polyamides...
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A facile method for Tauc exponent and corresponding electronic transitions determination in semiconductors directly from UV–Vis spectroscopy data
PublicationIn this work, a facile method allowing for estimation of the exponent in the Tauc equation directly from the UV–vis spectra is presented. It is based on the Taylor expansion of the logarithmic version of the Tauc equation. The Tauc exponent is calculated from the tangent slope of the absorption data. Knowledge of this coefficient provides information about the optical transition types and is used as an input for the calculations...
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Current harmonic controller in multiple reference frames for series active power filter integrated with 18-pulse diode rectifier
PublicationThe paper presents the control system and selected results of experimental tests of the AC/DC power converter consisting of an 18-pulse diode rectifier based on coupled reactors and a serial active power filter. Proportional integral controllers with decoupling components are implemented in multiple reference frames for selective line current harmonic suppression. The regulator is provided with a backtracking anti-windup mechanism...