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Faculty of Applied Physics and Mathematics
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Catalog Publications
Year 2018
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Daytime Acute Non-Visual Alerting Response in Brain Activity Occurs as a Result of Short- and Long-Wavelengths of Light
PublicationVery recent preliminary findings concerning the alerting capacities of light stimulus with long-wavelengths suggest the existence of neural pathways other than melatonin suppression that trigger the nonvisual response. Though the nonvisual effects of light during the daytime have not been investigated thoroughly, they are definitely worth investigating. The purpose of the present study is to enrich existing evidence by describing...
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Decomposition of Acoustic and Entropy Modes in a Non-Isothermal Gas Affected by a Mass Force
PublicationDiagnostics and decomposition of atmospheric disturbances in a planar flow are considered in this work. The study examines a situation in which the stationary equilibrium temperature of a gas may depend on the vertical coordinate due to external forces. The relations connecting perturbations are analytically established. These perturbations specify acoustic and entropy modes in an arbitrary stratified gas affected by a constant...
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Dependence between Ionic Liquid Structure and Mechanism of Visible-Light-Induced Activity of TiO2 Obtained by Ionic-Liquid-Assisted Solvothermal Synthesis
PublicationBecause of the tremendous structural diversityof ionic liquids (ILs), simple transfer of observations performed for one IL used for IL-TiO2 preparation on different samples is not possible. Therefore, four ionic liquids, all containing distinct nitrogen-bearing organic cations (pyridinium, pyrrolidinium, ammonium, imidazolium), were used for the first time for the preparation of IL-TiO2 composites. The role of the individual IL...
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Design, Synthesis, and Enzymatic Evaluation of Novel ZnO Quantum Dot-Based Assay for Detection of Proteinase 3 Activity
PublicationHerein, the synthesis and application of functionalized quantum dot-based protease probes is described. Such probes are composed of nontoxic ZnO nanocrystals decorated by amino groups followed by linker and labeled peptide attachment. Spherical NH2-terminated ZnO quantum dots (QDs) with the average size ranging from 4 to 8 nm and strong emission centered at 530 nm were prepared using the sol−gel method. The fluorescence of ZnO...
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Determination of ionic conductivity in the Bi-Si-O and Pb-Si-O glasses
PublicationImpedance spectroscopy measurements in various gas atmospheres were carried out in order to explain the doubts about the type of carriers and the mechanism of electrical conductivity in Bi-Si-O and Pb-Si-O glasses. In bismuth silicate glass, a typical ionic conductivity with oxygen ions as charge carriers was observed. The level of electrical conductivity of the glass at 400 °C was 5 × 10−8 S·cm−1 , with the activation energy of...
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Dissociative electron attachment and anion-induced dimerization in pyruvic acid
PublicationWe report partial cross sections for the dissociative electron attachment to pyruvic acid. A rich fragmentation dynamics is observed. Electronic structure calculations facilitate the identification of complex rearrangement reactions that occur during the dissociation. Furthermore, a number of fragment anions produced at electron energies close to 0 eV are observed, that cannot originate from single electron-molecule collisions....
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DL_MG: A Parallel Multigrid Poisson and Poisson–Boltzmann Solver for Electronic Structure Calculations in Vacuum and Solution
PublicationThe solution of the Poisson equation is a crucial step in electronic structure calculations, yielding the electrostatic potential -- a key component of the quantum mechanical Hamiltonian. In recent decades, theoretical advances and increases in computer performance have made it possible to simulate the electronic structure of extended systems in complex environments. This requires the solution of more complicated variants of the...
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Dynamics of a simplified HPT model in relation to 24h TSH profiles
PublicationWe propose a simplified mathematical model of the hypothalamus-pituitary-thyroid (HPT) axis in an endocrine system. The considered model is a modification of the model proposed by Mukhopadhyay and Bhattacharyya in [10]. Our system of delay differential equations reconstructs the HPT axis in relation to 24h profiles of human in physiological conditions. Homeostatic control of the thyroid-pituitary axis is considered by using...
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Dynamics of Field Line Mappings in Magnetic Flux Tubes
PublicationWe study the topological constraints on the dynamics of magnetic field lines in flux tubes. Our approach is based on the application of the topological invariant: fixed point index. We consider periodic flux tubes and find various restrictions on the field lines that come from the sequence of fixed point indices of iterations. We also analyze the case of a tube with a cylindrical obstacle, deducing some special dynamical properties...
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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
PublicationThe 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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Electrical properties of Na2O-CaO-P2O5 glasses doped with SiO2 and Si3N4
PublicationSodium-calcium-phosphate glasses doped with SiO2 or Si3N4 having similar sodium ion concentrations were prepared by melt quenching. The conductivity was measured by impedance spectroscopy under nitrogen atmosphere in a wide frequency range (10 mHz–1 MHz) and wide temperature range (153–473 K). At 36.6 °C, DC conductivities of all glasses vary between 1.1 ∗ 10−12 and 8.9 ∗ 10−12 S cm−1 and have similar activation energies (between...
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Electrochemically Obtained TiO2/CuxOy Nanotube Arrays Presenting a Photocatalytic Response in Processes of Pollutants Degradation and Bacteria Inactivation in Aqueous Phase
PublicationTiO2/CuxOy nanotube (NT) arrays were synthesized using the anodization method in the presence of ethylene glycol and different parameters applied. The presence, morphology, and chemical character of the obtained structures was characterized using a variety of methods—SEM (scanning electron microscopy), XPS (X-ray photoelectron spectroscopy), XRD (X-ray crystallography), PL (photoluminescence), and EDX (energy-dispersive X-ray spectroscopy)....
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Electron attachment to hexafluoropropylene oxide (HFPO)
PublicationWe probe the electron attachment in hexafluoropropylene oxide (HFPO), C3F6O, a gas widely used in plasma technologies. We determine the absolute electron attachment cross section using two completely different experimental approaches: (i) a crossed-beam experiment at single collision conditions (local pressures of 5 × 10−4 mbar) and (ii) a pulsed Townsend experiment at pressures of 20–100 mbar. In the latter method, the cross sections...
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Electron collisions with cyanoacetylene HC3N : Vibrational excitation and dissociative electron attachment
PublicationWe experimentally probe electron collisions with HC3N in the energy range from 0 to 10 eV with the focus on vibrational excitation and dissociative electron attachment. The vibrational excitation cross sections show a number of resonances which are mode specific: the two dominant π∗ resonances are visible in the excitation of all the vibrational modes; however, broad σ ∗ resonances are visible only in certain bond-stretching vibrational...
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Electron impact ionization and cationic fragmentation of the pyridazine molecules
PublicationElectron impact mass spectroscopy was used to investigate ionization and cationic fragmentation of the pyridazine (1,2 diazine), C4H4N2, molecules in the gas phase. The mass spectra were measured and the observed mass peaks assigned to the corresponding cations. The appearance energies of most of the cationic fragments were determined and the possible fragmentation processes are discussed. The total cross section for electron...
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Electron interactions with Bis(pentamethylcyclopentadienyl) titanium(IV) dichloride and difluoride
PublicationWe 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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Electron Scattering on X(CH3)4 Molecules: Applicability of Simple Additivity Rule and Role of Methylation
PublicationTo investigate influence of target methylation (substitution of a hydrogen atom by methyl group) on electron-collision processes we compare absolute total cross sections for XH4 and X(CH3)4 molecules, where X is Si and Ge, respectively. We also compare experimental TCSs energy dependencies with estimated data obtained using simple formula and TCSs for methyl group and those for SiH4 and GeH4. Electron-scattering TCSs for mentioned...
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Electronic structure and rovibrational predissociation of the 2^1Π state in KLi
PublicationAdiabatic potential energy curves of the 3^1Σ^+, 3^3Σ^+, 2^1Π and 2^3Π states correlating for large internuclear distance with the K(4s) + Li(2p) atomic asymptote were calculated. Very good agreement between the calculated and the experimental curve of the 2^1Π state allowed for a reliable description of the dissociation process through a small (∼20 cm−1 for J = 0) potential energy barrier. The barrier supports several rovibrational...
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Electron-impact dissociation of molecular hydrogen: benchmark cross sections
PublicationWe present a joint experimental and theoretical investigation of a fundamental process in atomic and molecular physics: electron impact excitation of molecular hydrogen’s (H2) most dominant transition (X1Σg+ → b3Σu+). Excitation of this state is by far the main channel that causes the dissociation of H2 into H + H atoms at low energies. The Convergent Close-Coupling (CCC) calculations predicted significant, more than factor of...
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Electron-impact ionization cross section of formic acid
PublicationExperimental electron-impact ionization cross sections of one of the simplest carboxylic acids, formic acid, are presented. The molecular target was studied in two independent experimental setups applying different methods: the total ion collection and the electron–impact mass spectrometry methods. Experimental data were taken at incident electron energies ranging from ionization threshold [11.31 eV; J.C. Traeger, Int. J. Mass...
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Entangled Histories vs. the Two-State-Vector Formalism - Towards a Better Understanding of Quantum Temporal Correlations
PublicationThe Two-State-Vector formalism and the Entangled Histories formalism are attempts to betterunderstand quantum correlations in time. Both formalisms share some similarities, but they are notidentical, having subtle differences in their interpretation and manipulation of quantum temporalstructures. However, the main objective of this paper is to prove that, with appropriately definedscalar products, both formalisms can be...
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Entropy Production Associated with Aggregation into Granules in a Subdiffusive Environment
PublicationWe study the entropy production that is associated with the growing or shrinking of a small granule in, for instance, a colloidal suspension or in an aggregating polymer chain. A granule will fluctuate in size when the energy of binding is comparable to k_{B}T, which is the “quantum” of Brownian energy. Especially for polymers, the conformational energy landscape is often rough and has been commonly modeled as being self-similar...
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Extended phase diagram of RNiC2 family: Linear scaling of the Peierls temperature
PublicationPhysical properties for the late-lanthanide-based RNiC2 (R = Dy, Ho, Er, and Tm) ternary compounds are reported. All the compounds show antiferromagnetic ground state with the Néel temperature ranging from 3.4 K for HoNiC2 to 8.5 K for ErNiC2. The results of the transport and galvanomagnetic properties confirm a charge density wave state at and above room temperature with transition temperatures TCDW = 284, 335, 366, and 394 K for...
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Fabrication, structural and electrical properties of Sr(V,Nb)O 3-δ perovskite materials
PublicationThe SrV1-xNbxO3-δ materials with different niobium content in perovskite B-sublattice were prepared by a solid-state reaction process. The microstructure and phase compositions of obtained samples were analyzed by the X-ray diffraction technique (XRD) and scanning electron microscopy (SEM). The electrical conductivity of samples was measured by a DC 4-wire method in range of 100–600 °C in different gas conditions. The oxidation...
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Fixed point indices of iterates of a low-dimensional diffeomorphism at a fixed point which is an isolated invariant set
PublicationLet f be an R^n-diffeomorphism, where n = 2, 3, for which {0} is an isolated invariant set. We determine all possible forms of the sequences of fixed point indices of iterates of f at 0, {ind(f n, 0)}_n, confirming in R3 the conjecture of Ruiz del Portal and Salazar (J Differ Equ 249, 989–1013, 2010).
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Formation of intermetallic compounds in the solid-liquid composites of the Ga-Ni system
PublicationThe processes of formation of intermetallic compounds in the composite system of liquid gallium-nickel powder by the methods of x-ray diffraction, scanning electron microscopy and differential thermal analysis have been studied. A change in the phase composition was discovered and the influence of thermal treatment of the composites under investigation on the phase formation processes was analyzed. The mechanism of gallium enriched...
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Fractional Calculus Evaluation of Hyaluronic Acid Crosslinking in a Nanoscopic Part of Articular Cartilage Model System
PublicationThis work presents a study of the mechanism of physical crosslinking of hyaluronic acid in the presence of common phospholipids in synovial joint organ systems. Molecular dynamic simulations have been executed to understand the formation of hyaluronan networks at various phospholipid concentrations. The results of the simulations suggest that the mechanisms exhibit subdiffusion characteristics. Transportation quantities derive...
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From unextendible product bases to genuinely entangled subspaces
PublicationUnextendible product bases (UPBs) are interesting mathematical objects arising in composite Hilbert spaces that have found various applications in quantum information theory, for instance in a construction of bound entangled states or Bell inequalities without quantum violation. They are closely related to another important notion, completely entangled subspaces (CESs), which are those that do not contain any fully separable pure...
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Furan Fragmentation in the Gas Phase: New Insights from Statistical and Molecular Dynamics Calculations
PublicationWe present a complete exploration of the different fragmentation mechanisms of furan (C4H4O) operating at low and high energies. Three different theoretical approaches are combined to determine the structure of all possible reaction intermediates, many of them not described in previous studies, and a large number of pathways involving three types of fundamental elementary mechanisms: isomerization, fragmentation, and H/H2 loss...
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Heteroclinic solutions of Allen-Cahn type equations with a general elliptic operator
PublicationWe consider a generalization of the Allen-Cahn type equation in divergence form $-\rm{div}(\nabla G(\nabla u(x,y)))+F_u(x,y,u(x,y))=0$. This is more general than the usual Laplace operator. We prove the existence and regularity of heteroclinic solutions under standard ellipticity and $m$-growth conditions.
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Highly Active TiO2 Microspheres Formation in the Presence of Ethylammonium Nitrate Ionic Liquid
PublicationSpherical microparticles of TiO2 were synthesized by the ionic liquid-assisted solvothermal method at different reaction times (3, 6, 12, and 24 h). The properties of the prepared photocatalysts were investigated by means of UV-VIS diffuse-reflectance spectroscopy (DRS), Brunauer–Emmett–Teller (BET) surface area measurements, scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), and X-ray photoelectron spectroscopy...
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Hyaluronan-Chondroitin Sulfate Anomalous Crosslinking Due to Temperature Changes
PublicationGlycosaminoglycans are a wide class of biopolymers showing great lubricating properties due to their structure and high affinity to water. Two of them, hyaluronic acid and chondroitin sulfate, play an important role in articular cartilage lubrication. In this work, we present results of the all-atom molecular dynamics simulations of both molecules placed in water-based solution. To mimic changes of the physiological conditions,...
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Improvement of opipramol base solubility by complexation with β-cyclodextrin
PublicationOpipramol (OPI), a tricyclic antidepressant and anxiolytic compound, is administered orally in the form of a dihydrochloride. Salt form of the drug has a higher solubility in water and hence bioavailability and stability. A similar effect can be achieved by closing the hydrophobic part of the drug molecule in the cyclodextrin cavity. The paper presents opipramol inclusion complexes with beta-cyclodextrin (β-CD) in 1:1 molar ratio....
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Influence of excitons interaction with charge carriers on photovoltaic parameters in organic solar cells
PublicationWe report on theoretical analysis of excitons annihilation on charge carriers in organic solar cells. Numerical calculations based on transient one-dimensional drift-diffusion model have been carried out. An impact of three quantities (an annihilation rate constant, an exciton mobility and a recombination reduction factor) on current density and concentrations of charge carriers and excitons is investigated. Finally, we discuss...
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Influence of synthesis conditions on glass formation, structure and thermal properties in the Na 2 O-CaO-P 2 O 5 system doped with Si 3 N 4 and Mg
PublicationOxynitride phosphate glasses and glass-ceramics were prepared using new synthesis routes for phosphate glasses. Materials were melted from pre-prepared glass samples in the system Na-Ca-P-O with addition of Mg and/or Si3N4 powders under different preparation conditions. The melting process was conducted at 1000–1500 °C either under air or nitrogen atmosphere to obtain materials with different nitrogen content. Their topography...
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Influence of the Spectral Quality of Light on Daytime Alertness Levels in Humans
PublicationExposure 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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Influence of yttria surface modification on high temperature corrosion of porous Ni22Cr alloy
PublicationProtective coatings for porous alloys for high temperature use are relatively new materials. Their main drawback is high temperature corrosion. In this work protective coatings based the on Y-precursor infiltrated into the sintered Ni22Cr alloys are studied at 700°C. Effects of the amount of the protective phase on the resulting corrosion properties are evaluated in air and humidified hydrogen. Weight gain of the samples, their...
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Integrate-and-fire models with an almost periodic input function
PublicationWe investigate leaky integrate-and-fire models (LIF models for short) driven by Stepanov and μ-almost periodic functions. Special attention is paid to the properties of the firing map and its displacement, which give information about the spiking behavior of the considered system. We provide conditions under which such maps are well-defined and are uniformly continuous. We show that the LIF models with Stepanov almost periodic...
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Interatomic potential suitable for the modeling of penta-graphene: Molecular statics/molecular dynamics studies
PublicationWe test the potentials available for elemental carbon, with the scope to choose the potential suitable for the modeling of penta-graphene, the latest two dimensional carbon allotrope. By using molecular statics and molecular dynamics simulations we show that there is only one potential e namely the Tersoff-type potential proposed by Erhart and Albe in 2005 e which is able to correctly describe all the important features of penta-graphene....
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Investigations of the optical activity of nonlinear crystals by means of dual-wavelength polarimeter
PublicationA dual-wavelength method in high accuracy polarimetry has been successfully tested and applied to measure optical activity (OA) of nonlinear crystals. In proposed polarimetric scheme two neighboring semiconductor laser wavelengths (635 and 650 nm) are used, which increases number of parameters measured simultaneously and improves the data processing. By neglecting dispersion of eigen wave ellipticity in crystals, more efficient...
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IR and Raman study of oxy-nitride glasses
PublicationVarious silicate and phosphate glasses with and without nitride addition were structurally characterized by IR and Raman spectroscopy. The studied glass systems include Na-Ca-P-O-N (1), AE-Si-O-N (with AE=Mg, Ca, Sr, Ba)(2), La-Si-O-N (3) as well as the Na-(Li)-Be-O-(N) (4,5) system. The samples were prepared by different techniques such as remelting of pre-prepared glass samples of the oxide systems with Mg and/or Si3N4 powders...
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Isolation of the relative decrease in magnetic permeability contribution to reluctance of an open magnetic circuit based on stray field measurements
PublicationThe goal of the study was to evaluate a relative decrease in magnetic permeability in open magnetic circuits based on stray magnetic field measurements. The boundary element method was used to simulate magnetic circuits with variable geometry and variable magnetic permeability. The simulated magnetic circuits were rectangular or bone-shaped flat samples. Reluctance was increased in the middle of the samples resulting in leakage...
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La 15 Nb x Ge 9 : a superstructure of the Mn 5 Si 3 structure type with interstitial Nb atoms
PublicationThe crystal structure and elementary properties of La15NbxGe9 are reported. Single-crystal X-ray diffraction,from a crystallite with only 0.12 Nb/formula unit, reveals that this compound, although transition metal deficient, crystallizes in a hexagonal “15-1-9”-like structure type, space group P63mc (no. 186) with lattice parameters a = b = 15.5017(2) Å, c = 6.9173(2) Å. The physical properties were examined by specific heat and resistivity...
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Low energy differential elastic electron scattering from acetonitrile (CH3CN)
PublicationMeasurements of elastic differential cross sections for electron scattering from acetonitrile (CH3CN) have been performed utilizing a crossed electron-molecular beam experiment and with the relative flow method, for the incident electron energy range of 0.7 eV–30 eV and the scattering angle range of 10◦–130◦. These differential cross sections have been used to calculate the elastic integral and momentum- transfer cross sections,...
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Low temperature deposition of dense MnCo 2 O 4 protective coatings for steel interconnects of solid oxide cells
PublicationIn this work manganese cobalt spinel (MnCo2O4) coatings were deposited on steel substrates by spray pyrolysis at 390 °C. This is at much lower temperatures than previously reported (typically in excess of 900 °C). It was possible to produce coatings with well controlled thickness (2-5-10 μm). The as-deposited coatings were evaluated for their microstructural changes and electrical conductivity up to 800 °C. Results confirm the...
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Low-energy electron scattering from molecular hydrogen: Excitation of the X1Σg+ to b3Σu+ transition
PublicationWe present time-of-flight differential cross-section measurements and convergent close-coupling calculations of differential cross sections for the electron-impact excitation of the X 1 g + → b 3 u + transition in molecular hydrogen. A part of this work was recently published [M. Zawadzki et al., Phys. Rev. A 97, 050702(R) (2018)]. In this work, agreement between theory and experiment is excellent overall, and marks a transition...
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Magnetic field effects in dye-sensitized and organic solar cells
PublicationThe charge recombination and exciton dissociation are generally recognized as the basic electronic processes limiting the efficiency of photovoltaic devices. The aim of this thesis is to understand the electronic processes limiting the operation of efficient solar cells with particular emphasis on the role of electronic states endowed with magnetic dipole moment. The research work is divided into two parts. The first part deals...
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Magnetic field gradient as the most useful signal for detection of flaws using MFL technique
PublicationThe magnetic flux leakage (MFL) technique is extensively used for detection of flaws as well as for evaluation of their dimensions in ferromagnetic materials. However, proper analysis of the MFL signal is hindered by the MFL sensor velocity causing distortions of this signal. Traditionally measured components of the MFL signal are particularly sensitive to the scanning velocity. In this paper, an another signal – the gradient of...
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Magnetoacoustic heating in a quasi-isentropic magnetic gas
PublicationThe nonlinear heating of a plasma which associates with the transfer of energy of magnetoacoustic waves into that of the entropy mode, is analytically studied. A plasma is uniform and motionless at equilibrium. Perturbations in a plasma are described by a system of ideal magnetohydrodynamic equations. The equilibrium straight magnetic strength and the wave vector form a constant angle which varies from 0 to π/2. There exist four...
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Magnetoacoustic Heating in Nonisentropic Plasma Caused by Different Kinds of Heating-Cooling Function
PublicationThe nonlinear phenomena which associate with magnetoacoustic waves in a plasma are analytically studied. A plasma is an open system with external inflow of energy and radiation losses. A plasma’s flow may be isentropically stable or unstable. The nonlinear phenomena occur differently in dependence on stability or instability of a plasma’s flow. The nonlinear instantaneous equation which describes dynamics of nonwave entropy mode...