Krzysztof Tadyszak - Academia.edu (original) (raw)

Papers by Krzysztof Tadyszak

Journal of Inorganic Biochemistry, Oct 1, 2017

Electron magnetic resonance data on high-spin Mn(III; S = 2) ions in porphyrinic and salen comple... more Electron magnetic resonance data on high-spin Mn(III; S = 2) ions in porphyrinic and salen complexes modeled by microscopic spin Hamiltonian approach

Polyhedron, May 1, 2017

The zero-field splitting parameters (ZFSPs), aka magnetic anisotropy (MA) parameters, are crucial... more The zero-field splitting parameters (ZFSPs), aka magnetic anisotropy (MA) parameters, are crucial for description of transition ions. Compatibility of ZFSPs is indispensable for proper interpretation of experimental and theoretical data. To achieve compatibility of orthorhombic ZFSPs reported for single magnetic 3d N adatoms on surfaces, the distinct nature of ZFS quantities and MA ones, and their interrelationships, are elucidated. The terminological confusion prevalent in adatoms studies results in detrimental consequences, e.g. erroneous values of the true uniaxial MA constant K and/or the axial ZFSP D. It is shown that the intrinsic features of the true orthorhombic ZFSPs: D and E (rhombic) in the conventional notation or B q 2 (b q 2 , q = 0, 2) in the Stevens notation, bear critically on compatibility of ZFSP sets. Since the standard ZFSP sets (0 < k E/D 1/3) and non-standard ones (k outside the standard region) belong to disparate regions of the ZFS parameter space, such sets are intrinsically incompatible and cannot be directly compared. The orthorhombic standardization, based on the rhombicity ratio k E/D, is performed to reanalyze the non-standard ZFSP sets identified in recent adatoms studies. The alternative physically equivalent ZFSP solutions that could equally well be obtained by fitting inelastic tunneling spectroscopy (ITS) data or conductance spectra data are provided. Disregarding the intrinsic features may lead to misleading conclusions, e.g. apparently highly rhombic ZFSP set (k = 1) represents actually purely axial case (E 0). The results enable meaningful comparison of ZFSP data taken from various sources.

Proceedings of SPIE, Feb 8, 2017

For more flexibility of environmental perception by artificial intelligence it is needed to exist... more For more flexibility of environmental perception by artificial intelligence it is needed to exist the supporting software modules, which will be able to automate the creation of specific language syntax and to make a further analysis for relevant decisions based on semantic functions. According of our proposed approach, of which implementation it is possible to create the couples of formal rules of given sentences (in case of natural languages) or statements (in case of special languages) by helping of computer vision, speech recognition or editable text conversion system for further automatic improvement. In other words, we have developed an approach, by which it can be achieved to significantly improve the training process automation of artificial intelligence, which as a result will give us a higher level of self-developing skills independently from us (from users). At the base of our approach we have developed a software demo version, which includes the algorithm and software code for the entire above mentioned component's implementation (computer vision, speech recognition and editable text conversion system). The program has the ability to work in a multi - stream mode and simultaneously create a syntax based on receiving information from several sources.

Acta Physica Polonica A, Jul 1, 2017

The electron magnetic resonance data on high-spin (S = 2) manganese(III) 3d 4 ion in tetraphenylp... more The electron magnetic resonance data on high-spin (S = 2) manganese(III) 3d 4 ion in tetraphenylporphyrinato chloride complex (MnTPPCl) obtained by high-frequency techniques are reanalysed. Preliminary results of semiempirical modeling of the spin Hamiltonian parameters for Mn(III) in MnTPPCl are presented. The microscopic spin Hamiltonian approach is utilized to predict the zero-field splitting and the Zeeman electronic parameters. It is found that for Mn(III) ions in MnTPPCl matching the experimental spin Hamiltonian parameters and the theoretical ones based on the ligand-field energy levels (∆i) within the 5 D multiplet only may not be suitable for this system. Contributions due to the levels arising from the higher-lying 3 H multiplet need to be taken into account in order to determine the reasonable values of microscopic parameters describing Mn(III) ions in MnTPPCl.

Materials Chemistry and Physics, 2020

Cellular glassy carbon used as cell scaffold. � Sugar blowing technique: Sucrose as organic precu... more Cellular glassy carbon used as cell scaffold. � Sugar blowing technique: Sucrose as organic precursor and ammonia chloride blowing agent. � Magnetic and electrical characterization of carbon cellular foams. � Viability of non-malignant HEK-293 and cancer SH-SY5Y human cell lines incubated with glassy carbon foams.

Microporous and Mesoporous Materials, Mar 1, 2014

The 1,3-dithiole-2-thione-4,5-dithiolate (C 3 S 5 2dmit) complexes with Cu(II) in solutions and d... more The 1,3-dithiole-2-thione-4,5-dithiolate (C 3 S 5 2dmit) complexes with Cu(II) in solutions and deposited into zeolite NaA and into metal-organic framework (MOF) with zeolitic imidazole structure ZIF-Cu(IM) 2 B were studied by UV-vis and EPR spectroscopy. UV-vis spectra show that intermolecular p-p ⁄ transitions existing in the visible region can be used for an identification of the molecules deposited in solid matrices. EPR of Cu(dmit) 2 complexes in frozen (77 K) DMF (dimethylformamide) solution indicates tetrahedral CuS 4 coordination with compressed structure of D 2d symmetry and EPR parameters g || = 2.089, g \ = 2.0257, A || = 145.4 Â 10 À4 and A \ = 29.8 Â 10 À4 cm À1. We were looking for such complexes after impregnation of the zeolites NaA with dmit solutions. We found that the Cu(dmit) 2 complex in zeolite NaA appears together with Cu(II) complexes being coordinated by host oxygen atoms. The Cu(dmit) 2 complexes are, however, deformed to the elongated D 2d symmetry. In ZIF-Cu(IM) 2 B the slightly more axially compressed tetrahedral Cu(dmit) 2 complexes appear as a result of coordination of the host Cu(II) ions with captured dmit molecules. The host structure is preserved, exchange coupling between host Cu(imidazole) 4 complexes is strongly weakened and separated Cu-imidazole and Cu(dmit) 2 complexes can be distinguished.

Journal of The Mechanical Behavior of Biomedical Materials, Mar 1, 2020

Micro-sized structures made from graphene oxide (GO) attract high interest for their extensive us... more Micro-sized structures made from graphene oxide (GO) attract high interest for their extensive use in tissue engineering. The fabrication and cytotoxicity of 3D graphene-based scaffolds so far have not been extensively discussed with relation to the flake sizes used. In this work we considered GO flakes of two different lognormal size distributions (GO: 4.9 � 3.8 μm and GO 1 h: 151.6 � 1.9 nm) as model flakes for fabrication of 3D graphenebased cell culture supports: paper (i.e. 3D layered film structure) and reduced graphene oxide (rGO) microfiber using hydrothermal methods. We then used two model cell lines of neuronal origin (SH-SY5Y and HEK-293) to study subsequent scaffolds surface-cells interactions. In particular, the adhesion of HEK cells to the formed structures was much higher than for SH-SY5Y cells, as evidenced by various atomic force, electron and optical microscopy techniques. Formed rGO microfibers had more desired nano-topography (surface roughness) for cell adhesion and growth than simple GO paper, making it ideal scaffold for neural tissue engineering. This work provides insights into the fundamental rules for fabrication of graphene oxide-based cell supports and their subsequently differing interactions with malignant and non-malignant cells.

Journal of Materials Science, Aug 16, 2018

This work presents the preparation and characterization of pristine and transition metal doped pa... more This work presents the preparation and characterization of pristine and transition metal doped partially reduced graphene oxide aerogels. The step-by-step preparation of aerogels from graphene oxide with an assistance of VCl 3 , CrCl 3 , FeCl 2 Á4H 2 O, CoCl 2 , NiCl 2 and CuCl 2 chlorides as reducing agents is shown and explained. The influence of reducing agents on the structural and magnetic properties of prepared aerogels is investigated. The use of electron paramagnetic resonance in purification during synthesis of GO and characterization afterwards is shown. It was found that VCl 3 was the strongest reducing agent leading to the formation of the most dense reduced graphene oxide aerogel, whereas vanadium is visible in EPR spectrum in form of V 4? complex as a VO 2? groups.

Journal of Magnetism and Magnetic Materials, Feb 1, 2019

Studies of magnetic adatoms on surfaces utilize experimental techniques (scanning tunneling micro... more Studies of magnetic adatoms on surfaces utilize experimental techniques (scanning tunneling microscopy (STM), inelastic tunneling spectroscopy (ITS) and ab-initio modeling methods. Several fundamental issues involved in these studies, being of utmost importance in view of potential technological applications, are critically examined and elucidated. This includes applications of the correspondence principle and relationships between the notions: magnetic anisotropy (MA), magnetic anisotropy energy (MAE), single-ion anisotropy (SIA), zero-field splitting (ZFS) as well as spin-flip energy of tunneling electrons and energy barrier to magnetization reversal. Proper quantum-mechanical relations between the uniaxial SIA constant K and the axial ZFS parameter D valid for the cases D > 0 and D < 0, as well as integer and half-integer spins, including S = 1/2, are derived. These considerations show that direct equating SIA with ZFS is unwarranted, whereas usage of the correspondence principle to justify such equating proves redundant. So-derived improper relations bear detrimentally on interpretation of STM/ITS and ab-initio results, e.g. for Co(S = 1) and Fe(S = 3/2) on Pt(111) yielding K (aka 'MAE') values differing from those obtained from the proper relations by 100 and 50 percent, respectively. Implications of confusion concerning the basic tenets for S = 1/2 systems, classical versus quantum spin approaches, and applicability of the crucial notions for magnetic adatoms are also discussed. spin which are included in H spin for TM and RE with an orbital singlet ground state, and (iii) the notion of magnetic anisotropy (MA)

RSC Advances, 2016

ZnO:Er3+–Yb3+@Gd2O3 nanostructures were obtained by “wet” chemistry methods – the sol–gel techniq... more ZnO:Er3+–Yb3+@Gd2O3 nanostructures were obtained by “wet” chemistry methods – the sol–gel technique for the preparation of ZnO and ZnO:Er3+–Yb3+ nanoparticles (NPs), and the seed deposition method for obtaining Gd2O3.

Materials, Jan 23, 2019

The high specific surface area of multilayered two-dimensional carbides called MXenes, is a criti... more The high specific surface area of multilayered two-dimensional carbides called MXenes, is a critical feature for their use in energy storage systems, especially supercapacitors. Therefore, the possibility of controlling this parameter is highly desired. This work presents the results of the influence of oxygen concentration during Ti 3 AlC 2 ternary carbide-MAX phase preparation on α-Al 2 O 3 particles content, and thus the porosity and specific surface area of the Ti 3 C 2 T x MXenes. In this research, three different Ti 3 AlC 2 samples were prepared, based on TiC-Ti 2 AlC powder mixtures, which were conditioned and cold pressed in argon, air and oxygen filled glove-boxes. As-prepared pellets were sintered, ground, sieved and etched using hydrofluoric acid. The MAX phase and MXene samples were analyzed using scanning electron microscopy and X-ray diffraction. The influence of the oxygen concentration on the MXene structures was confirmed by Brunauer-Emmett-Teller surface area determination. It was found that oxygen concentration plays an important role in the formation of α-Al 2 O 3 inclusions between MAX phase layers. The mortar grinding of the MAX phase powder and subsequent MXene fabrication process released the α-Al 2 O 3 impurities, which led to the formation of the porous MXene structures. However, some non-porous α-Al 2 O 3 particles remained inside the MXene structures. Those particles were found ingrown and irremovable, and thus decreased the MXene specific surface area. Keywords: MAX phases; Ti 3 AlC 2 ; MXenes; Ti 3 C 2 T x ; α-Al 2 O 3 particles; porosity

Applied Surface Science, Jun 1, 2019

According to theoretical predictions, the magnetic properties of MXene structures are determined ... more According to theoretical predictions, the magnetic properties of MXene structures are determined by the properties of the constitutive transition metals, defects in the MXene layers and the surface functional groups. We studied the magnetic properties of differently functionalized multilayered Ti 3 C 2 T x MXenes and compared them with those of Ti 3 AlC 2 and Ti 2 AlC MAX phases, as well as titanium carbide (TiC). The influence of the type and concentration of functional groups on MXene's magnetic properties was investigated by studying Ti 3 C 2 T x samples obtained by etching the aluminum layer from the Ti 3 AlC 2 MAX phase using (1) hydrofluoric acid, (2) chlorosulfonic acid and (3) hydrofluoric acid followed by chlorosulfonic acid. The samples prepared by hydrofluoric or chlorosulfonic acid only showed paramagnetic behavior, while MXenes prepared with an assistance of both acids were found to exhibit two different types of radicals and/or defects in the electron paramagnetic spectrum and mixed antiferromagnetic/paramagnetic behavior under external magnetic field of 100 Oe. The appearance of magnetic ordering was assigned to sulfur-based functional groups (-S 2 and-SO 3 H) introduced by chlorosulfonic acid. The obtained results confirm that the magnetic properties of Ti 3 C 2 T x MXenes may depend on the type and concentration of terminal functionalities.

Polymers, May 29, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Journal of physics, Dec 17, 2012

ABSTRACT Thin polymer films from 1-naphthylamine have been obtained for the first time by polymer... more ABSTRACT Thin polymer films from 1-naphthylamine have been obtained for the first time by polymerization at the cathode and anode in DC discharge. The morphology of the films synthesized at the cathode was examined by SEM and AFM. The elemental composition, chemical structure, and thermal stability of the polymer have been studied by pyrolysis chromatography, IR and UV spectroscopy, and thermogravimetry, respectively. The surface contact properties of the films and their thickness have been determined with a microinterferometer. Polymer was also investigated by ESR method.

Applied Surface Science, Nov 1, 2016

Epitaxial thin films of double perovskite Y(Ni 0.5 Mn 0.5)O 3 (001) and Y(Ni 0.5 Mn 0.5)O 3 (101)... more Epitaxial thin films of double perovskite Y(Ni 0.5 Mn 0.5)O 3 (001) and Y(Ni 0.5 Mn 0.5)O 3 (101) grown on SrTiO 3 (001) and SrTiO 3 (111), respectively, were studied by XPS and SQUID magnetometer. Temperature dependent Ti diffusion was detected in the Y(Ni 0.5 Mn 0.5)O 3 (101)/SrTiO 3 (111) samples, while no diffusion was observed in Y(Ni 0.5 Mn 0.5)O 3 (001)/SrTiO 3 (001) samples. It was observed that the use of a low ablation rate promoted ionic migrations, mainly due to the associated annealing time that samples undergo when grown at lower rates. The migration speed was determined by XPS analysis and its influence on the magnetic properties of the Y(Ni 0.5 Mn 0.5)O 3 (101) films was characterized and discussed.

Materials, Jul 16, 2022

Magnetic Resonance in Chemistry, Sep 14, 2015

A study concerning the image quality in electron paramagnetic resonance imaging in two-dimensiona... more A study concerning the image quality in electron paramagnetic resonance imaging in two-dimensional spatial experiments is presented. The aim of the measurements was to improve the signal-to-noise ratio (SNR) of the projections and the reconstructed image by applying modulation amplitude higher than the radical electron paramagnetic resonance linewidth. Data were gathered by applying four constant modulation amplitudes, where one was below 1/3 (A mod = 0.04 mT) of the radical linewidth (ΔB pp = 0.14 mT). Three other modulation amplitude values were used in this experiment, leading to undermodulated (A mod < 1/3 ΔB pp), partially overmodulated (A mod~1 /3 ΔB pp) and fully overmodulated (A mod > > 1/3 ΔB pp) projections. The advantages of an applied overmodulation condition were demonstrated in the study performed on a phantom containing four shapes of 1.25 mM water solution of 2, 2, 6, 6-tetramethyl-1-piperidinyloxyl. It was shown that even when the overmodulated reference spectrum was used in the deconvolution procedure, as well as the projection itself, the phantom shapes reconstructed as images directly correspond to those obtained in undermodulation conditions. It was shown that the best SNR of the reconstructed images is expected for the modulation amplitude close to 1/3 of the projection linewidth, which is defined as the distance from the first maximum to the last minimum of the gradient-broadened spectrum. For higher modulation amplitude, the SNR of the reconstructed image is decreased, even if the SNR of the measured projection is increased.

Nanomaterials, Apr 21, 2020

Carbon nanostructures are utilized in a plethora of applications ranging from biomedicine to elec... more Carbon nanostructures are utilized in a plethora of applications ranging from biomedicine to electronics. Particularly interesting are carbon nanostructured quantum dots that can be simultaneously used for bimodal therapies with both targeting and imaging capabilities. Here, magnetic and optical properties of graphene oxide quantum dots (GOQDs) prepared by the top-down technique from graphene oxide and obtained using the Hummers' method were studied. Graphene oxide was ultra-sonicated, boiled in HNO 3 , ultra-centrifuged, and finally filtrated, reaching a mean flake size of~30 nm with quantum dot properties. Flake size distributions were obtained from scanning electron microscopy (SEM) images after consecutive preparation steps. Energy-dispersive X-ray (EDX) confirmed that GOQDs were still oxidized after the fabrication procedure. Magnetic and photoluminescence measurements performed on the obtained GOQDs revealed their paramagnetic behavior and broad range optical photoluminescence around 500 nm, with magnetic moments of 2.41 µ B. Finally, electron paramagnetic resonance (EPR) was used to separate the unforeseen contributions and typically not taken into account metal contaminations, and radicals from carbon defects. This study contributes to a better understanding of magnetic properties of carbon nanostructures, which could in the future be used for the design of multimodal imaging agents.

Materials

This article focuses on EPR relaxation measurements in various carbon samples, e.g., natural carb... more This article focuses on EPR relaxation measurements in various carbon samples, e.g., natural carbons—anthracite, coal, higher anthraxolites, graphite; synthetically obtained carbons—glassy carbons, fullerenes, graphene, graphene oxide, reduced graphene oxide, graphite monocrystals, HOPG, nanoribbons, diamonds. The short introduction presents the basics of resonant electron spin relaxation techniques, briefly describing the obtained parameters. This review presents gathered results showing the processes leading to electron spin relaxation and typical ranges of electron spin relaxation rates for many different carbon types.