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Search results for: DOPING OF GRAPHENE OXIDE
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Copper and cobalt co-doped ceria as an anode catalyst for DIR-SOFCs fueled by biogas
PublicationThe nanocrystalline compounds of Co and Cu co-doped ceria (with up to 20 mol.% of dopants) were fabricated by the reverse microemulsion synthesis method. They were deposited in a form of layers on the surface of SOFC anode in an aim to act as electrochemically active materials for biogas reforming process. Fourier Transformed Infrared Spectroscopy was used to analyze a composition of outlet gases simultaneously with the tests of...
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Effects of Na+, K+ and B3+ Substitutions on the Electrical Properties of La10Si6O27 Ceramics
PublicationDoping of Na and K at La sites and of B at Si site in La10Si6O27 with oxyapatite structure and fabrication of their ceramics were made by solid-state reaction method. It was found that partial substitution of Na+ and K+ on La sites decreased the sinterability of the La10Si6O27 based ceramics, whereas partial substitution of B3+ on Si site imporved the sinterability. Na+ and K+ substitutions in La10-xNaxSi6O27-x and La10-xKxSi6O27-x...
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Thermochemistry of rare earth perovskites Na3xRE0.67−xTiO3 (RE = La, Ce)
PublicationHigh-temperature oxide melt solution calorimetry using sodium molybdate (3Na2O·4MoO3) solvent at 973 K was performed for the Na3xRE0.67−xTiO3 (RE = La, Ce) perovskite series. The enthalpies of formation of lanthanum perovskites from oxides (La2O3, Na2O, TiO2), are −107.25 ± 2.56, −93.83 ± 6.06, −80.68 ± 5.93, and −33.49 ± 4.26 kJ/mol and enthalpies of formation from elements are −1614.05 ± 5.37, −1596.44 ± 7.68, −1594.03 ± 7.58,...
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Tuning of the plasmon resonance location in Au nanostructures coated with a ultrathin film of Al2O3 – Optical measurements and FDTD simulations
PublicationThe Au nanostructures have been coated with an ultra-thin films of amorphous aluminium oxide. Optical absorption spectra show the influence of the thickness of Al2O3 on plasmon resonance wavelength. The observed red-shift of the resonance location with the increase of the thickness of the Al2O3 film, can be explained by the change in the dielectric function of this film. It allows control of the optical spectra of the coated particles....
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Mn-Co spinel coatings on Crofer 22 APU by electrophoretic deposition: Up scaling, performance in SOFC stack at 850 °C and compositional modifications
PublicationCeramic coatings for metallic interconnects play a key role in limiting corrosion and chromium evaporation in solid oxide cells. This study presents the upscaling of the electrophoretic deposition (EPD) technique to process Mn-Co spinels on real-dimension Crofer 22 APU interconnects and the test in a SOFC stack. Area specific resistance of long-term test conducted for 5000 h at 850 °C demonstrated that two-steps sintering has a...
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Effect of double thermal and electrochemical oxidation on titanium alloys for medical applications
PublicationThe research focuses on the development and characterization of innovative thin hybrid oxide coatings obtained in subsequent processes of thermal (TO) and electrochemical (EO) oxidation. Four different surface modifications were investigated and the microstructure was determined, the mechanical, chemical and biological properties of the Ti-13Nb-13Zr alloy were assessed using scanning electron microscopy, X-ray dispersion analysis,...
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Poloxamer: A versatile tri-block copolymer for biomedical applications
PublicationPoloxamers, also called Pluronic, belong to a unique class of synthetic tri-block copolymers containing central hydrophobic chains of poly(propylene oxide) sandwiched between two hydrophilic chains of poly(ethylene oxide). Some chemical characteristics of poloxamers such as temperature-dependent self-assembly and thermo-reversible behavior along with biocompatibility and physiochemical properties make poloxamer-based biomaterials...
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Thermodynamics of solid phases containing rare earth oxides
PublicationRare earth elements (RE) are incorporated into a large variety of complex oxide phases to provide tailored mechanical, electrical, optical, and magnetic properties. Thermodynamics control phase stability, materials compatibility in use, corrosion, and transformation. This review presents, in one compilation, the thermodynamic properties of a large number of such materials and discusses systematic trends in energetics and the factors...
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Multimodal Genetic Algorithm with Phase Analysis to Solve Complex Equations of Electromagnetic Analysis
PublicationIn this contribution, a new genetic-algorithm-based method of finding roots and poles of a complex function of a complex variable is presented. The algorithm employs the phase analysis of the function to explore the complex plane with the use of the genetic algorithm. Hence, the candidate regions of root and pole occurrences are selected and verified with the use of discrete Cauchy's argument principle. The algorithm is evaluated...
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Mechanical, durability, depolluting and electrical properties of multifunctional mortars prepared with commercial or waste carbon-based fillers
PublicationCarbon-based fillers from industrial wastes and commercial ones were compared to improve the properties of lime-based mixes. As commercial fillers, graphene nanoplatelets and activated carbon were used, whereas as industrial wastes a char obtained by the gasification of biomasses and a used foundry sand were chosen. Carbon-based wastes were found to be a good cost-effective alternative to commercial carbon based fillers to increase...
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Problem of Clogging in Drainage Systems in the Examples of the Zur and Podgaje Dams
PublicationDrainage plays an extremely important role in hydraulic structures, such as earth dams. Observations of drainage in hydraulic structures under various soil conditions indicate that the phenomenon of clogging can lead to a radical reduction in the efficiency of drainage, making it non-functional within a few years after construction. This article describes the problems of drainage clogging by iron oxide in the examples of the Zur...
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Progress in targeting tumor cells by using drug-magnetic nanoparticles conjugate.
PublicationTo limit the cytotoxicity of anticancer drugs against healthy cells, an appropriate carrier should be synthesized to deliver the drug to the tumor tissue only. A good solution is to anchor a magnetic nanoparticle to the molecule of the drug and to use a properly directed external magnetic field. We have shown that the improved by us synthesis of the conjugate of doxorubicin with iron-oxide magnetic nanoparticles allows a substantial...
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TiO2-based magnetic nanocomposites with core-shell structure
PublicationThe main aim of the doctoral dissertation was preparation and characterization of photocatalysts, with particular emphasis on modified titanium (IV) oxide photocatalysts, which can be applied for the degradation of organic pollutants not susceptible to biodegradation. A particularly important aspect of the work was the development of preparation method of nanocomposites with the magnetic core-shell and photocatalyst shell (TiO2)...
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Thermal Instability of Gold Thin Films
PublicationThe disintegration of a continuous metallic thin film leads to the formation of isolated islands, which can be used for the preparation of plasmonic structures. The transformation mechanism is driven by a thermally accelerated diffusion that leads to the minimalization of surface free energy in the system. In this paper, we report the results of our study on the disintegration of gold thin film and the formation of nanoislands...
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Spectroscopic studies of Nb-doped tricalcium phosphate glass-ceramics prepared by sol-gel method
PublicationCalcium-phosphate based glasses and glass-ceramics play a crucial role in the tissue engineering development. Apart from their high biocompatibility and excellent ability to undergo varying degrees of resorbability1, they exhibit relatively high bioactivity and due to that they are commonly used as bone and dental implants. A substantial research effort is devoted to improve calcium-phosphate materials physico-chemical properties...
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Polarization-dependent optical absorption in phosphorene flakes
PublicationThe interest of 2D materials is constantly increasing because of their very attractive mechanical, electrical and optical parameters. They have been used in many applications, e.g. photodetectors, sensors, modulators, insulators. One of the recently discovered 2D materials is phosphorene. In contrast to graphene, phosphorene has a direct bandgap tuned by numbers of layers in the 2D structure. The phosphorene flakes are strongly...
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Tailoring Defects in B, N-Codoped Carbon Nanowalls for Direct Electrochemical Oxidation of Glyphosate and its Metabolites
PublicationTailoring the defects in graphene and its related carbon allotropes has great potential to exploit their enhanced electrochemical properties for energy applications, environmental remediation, and sensing. Vertical graphene, also known as carbon nanowalls (CNWs), exhibits a large surface area, enhanced charge transfer capability, and high defect density, making it suitable for a wide range of emerging applications. However, precise...
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Non-metaldoped TiO2 nanotube arrays for high efficiency photocatalytic decomposition of organic species in water
PublicationTitanium dioxide is a well-known photoactive semiconductor with a variety of possible applications. The procedure of pollutant degradation is mainly performed using TiO2 powder suspension. It can also be exploited an immobilized catalyst on a solid support. Morphology and chemical doping have a great influence on TiO2 activity under illumination. Here we compare photoactivity of titania nanotube arrays doped with non-metal atoms:...
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Diamond-Phase (Sp3-C) Rich Boron-Doped Carbon Nanowalls (Sp2-C): A Physico-Chemical And Electrochemical Properties
PublicationThe growth of B-CNW with different boron doping levels controlled by the [B]/[C] ratio in plasma, and the influence of boron on the obtained material’s structure, surface morphology, electrical properties and electrochemical parameters, such as -ΔE and k°, were investigated. The fabricated boron-doped carbon nanowalls exhibit activity towards ferricyanide redox couple, reaching the peak separation value of only 85 mV. The flatband...
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Noncentrosymmetric superconductor with a bulk three-dimensional Dirac cone gapped by strong spin-orbit coupling
PublicationThe layered, noncentrosymmetric heavy element PbTaSe2 is found to be superconducting. We report its electronic properties accompanied by electronic-structure calculations. Specific heat, electrical resistivity, and magnetic-susceptibility measurements indicate that PbTaSe2 is a moderately coupled, type-IIBCSsuperconductor (Tc = 3.72 K, Ginzburg–Landau parameter κ = 17) with an electron-phonon coupling constant of λep = 0.74. Electronic-structure...
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Buckling Analysis of a Micro Composite Plate with Nano Coating Based on the Modified Couple Stress Theory
PublicationThe present study investigates the buckling of a thick sandwich plate under the biaxial non-uniform compression using the modified couple stress theory with various boundary conditions. For this purpose, the top and bottom faces are orthotropic graphene sheets and for the central core the isotropic soft materials are investigated. The simplified first order shear deformation theory (S-FSDT) is employed and the governing differential...
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Relativistic two-dimensional hydrogen-like atom in a weak magnetic field
PublicationA two-dimensional (2D) hydrogen-like atom with a relativistic Dirac electron, placed in a weak, static, uniform magnetic field perpendicular to the atomic plane, is considered. Closed forms of the first- and second-order Zeeman corrections to energy levels are calculated analytically, within the framework of the Rayleigh–Schrödinger perturbation theory, for an arbitrary electronic bound state. The second-order calculations are...
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Is the Solid Electrolyte Interphase an Extra-Charge Reservoir in Li-Ion Batteries?
PublicationAdvanced metal oxide electrodes in Li-ion batteries usually show reversible capacities exceeding the theoretically expected ones. Despite many studies and tentative interpretations, the origin of this extra-capacity is not assessed yet. Lithium storage can be increased through different chemical processes developing in the electrodes during charging cycles. The solid electrolyte interface (SEI), formed already during the first...
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Fault detection in the marine engine using a support vector data description method
PublicationFast detection and correct diagnosis of any engine condition changes are essential elements of safety andenvironmental protection. Many diagnostic algorithms significantly improve the detection of malfunctions.Studies on diagnostic methods are rarely reported and even less implemented in the marine engine industry.To fill this gap, this paper presents the Support Vector Data Description (SVDD) method as applied to thefault detection...
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Endothelial Dysfunction Driven by Hypoxia—The Influence of Oxygen Deficiency on NO Bioavailability
PublicationCardiovascular diseases (CVDs) are the leading cause of death worldwide. The initial stage of CVDs is characterized by endothelial dysfunction, defined as the limited bioavailability of nitric oxide (NO). Thus, any factors that interfere with the synthesis or metabolism of NO in endothelial cells are involved in CVD pathogenesis. It is well established that hypoxia is both the triggering factor as well as the accompanying factor...
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Morphology changes in Fe-Cr porous alloys upon high-temperature oxidation quantified by X-ray tomographic microscopy
PublicationThe effect of high-temperature oxidation at 850 C (10 h, 30 h, 100 h) and 900 C (10 h) on porous (30 % porosity) ferritic stainless steel (Fe22Cr) has been investigated using synchrotron tomographic microscopy, which allowed for visualisation, separation and quantitative analysis of the metallic core, closed pores, open pores and oxide scale phase. The same regions within the samples were investigated before and after oxidation...
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Protonic Ceramic Fuel Cells as novel electrochemical devices
PublicationProton ceramic conductors are novel materials which are interesting from the application point of view. For example, Protonic Ceramic Fuel Cells (PCFCs) is a type of a solid oxide fuel cell, which uses proton ceramic conductors as an electrolyte. Scientists are looking for the most efficient materials for these devices. In recent years main focus has been put on the search for new proton and mixed proton-electron conductors which...
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Hybrid electrode materials for fast performance devices
PublicationEnergy storage devices such as Electrochemical Double Layer Capacitors and other types of the electrochemical capacitors require chemically stable, non-soluble, electrochemically active electrode materials compatible with appropriate electrolytes. Factors which determine their applicability are derived from so called electrochemical window of electroltes, nature of charge accumulation and their kinetics. On the other hand technological...
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A first-principles study of electronic and magnetic properties of 4d transition metals doped in Wurtzite GaN for spintronics applications
PublicationWe studied the electronic and magnetic properties of wurtzite GaN (w-GaN) doped with different concentrations of the 4d transition metal ions Nb, Mo, and Ru. We incorporated spin-polarized plane-wave density functional theory within an ultrasoft pseudopotential formalism. The 4d transition metals were doped at different geometrical sites to determine the geometry with the lowest total energy and the one that induced the largest...
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Gas Composition Influence on the Properties of Boron-Doped Diamond Films Deposited on the Fused Silica
PublicationThe main subject of this study are molecular structures and optical properties of boron-doped diamond films with [B]/[C] ppm ratio between 1000 and 10 000, fabricated in two molar ratios of CH 4 -H 2 mixture (1 % and 4 %). Boron-doped diamond (BDD) film on the fused silica was presented as a conductive coating for optical and electronic purposes. The scanning electron microscopy images showed homogenous and polycrystalline surface...
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Study of nanomechanical properties of (1-y)BST-yMgO thin films
PublicationIn the present study thin films of MgO – modified Ba0.6Sr0.4TiO3 (BST60/40) solid solution were prepared by the sol-gel-type chemical solution deposition method on stainless steel substrates. A multilayer spin-coating approach was utilized for the Ba0.6Sr0.4TiO3-MgO thin film deposition with subsequent thermal annealing at T=650-750C. Dried BST60/40-MgO gel powders were studied with thermogravimetric and differential thermal analysis...
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Enhanced photocatalytic activity of transparent carbon nanowall/TiO2 heterostructures
PublicationThe synthesis of novel tunable carbon-based nanostructure represented a pivotal point to enhance the efficiency of existing photocatalysts and to extend their applicability to a wider number of sustainable processes. In this letter, we describe a transparent photocatalytic heterostructure by growing boron-doped carbon nanowalls (B-CNWs) on quartz, followed by a simple TiO2 sol-gel deposition. The effect on the thickness and boron-doping...
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High-temperature properties of titanium-substituted yttrium niobate
Publicationhe defect fluorite titanium-doped yttrium niobate samples Y3Nb1−xTixO7−δ have been synthesized and investigated by the means of high-temperature X-ray diffraction, dilatometry, and thermogravimetry. Thermal expansion coefficients (TECs) as well as chemical expansion coefficients for material with 5, 10, and 15 mol% of titanium were determined. All investigated samples exhibit chemical contraction caused by Ti doping. The values...
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Donor-substituted SrTi1+xO3−δ anodes for SOFC
PublicationNonstoichiometric Nb-substituted SrTiO3 compounds were investigated in order to discuss the influence of nonstoichiometry at the sample properties in the light of recent results reported in the literature. Structural and electrical properties of samples were characterized. Investigated compounds were also applied as anodes for Solid Oxide Fuel Cells and their reactivity with YSZ electrolyte was examined. The defect chemistry explaining...
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Improvement of microstructure and mechanical properties of high dense sic ceramics manufactured by high-speed hot pressing
PublicationNon-oxide ceramics possess high physical-mechanical properties, corrosion and radiation resistance, which can be used as a protective materials for radioactive wastes disposal. The aim of the present study was the manufacturing of high density SiC ceramics with advanced physical and mechanical parameters. The high performance on the properties of produced ceramics was determined by the dense and monolithic structure. The densified...
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Determining the leakage current resistive component by the orthogonal vector method
PublicationThe measurement of the metal – oxide surge arresters (MOSA) leakage current and the analysis of its components is a key diagnostic criterion according to technical standards. During on site MOSA condition assessment, the easy way is based on the measurement only leakage current, without the inconvenient live working measurements of supply voltage. Orthogonal vectors method of determination the resistive leakage current is presented....
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Fabrication and structural properties of Y and Fe co-doped SrTiO3 nanoceramics for SOFC
PublicationYttria and iron co-doped strontium titanate perovskites, (Y0,07Sr0,93Ti1-xFexO3-δx=0,1; 0,2) samples were fabricated by two methods: solid-state synthesis (SS) and the Pechinisol-gel modified method. The morphology of samples were measured by SEM and X-raydiffraction. Results were compared and discussed. The strong relationship between fabricationprocedure and microstructure has been proven. It was also observed, that the nanoceramicsobtained...
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EFFECT OF SURFACE STATE AND STRESS ON AN OXIDATION OF THE ZIRCALOY-2 ALLOY
PublicationZr alloys are widely used as materials for nuclear fuel pellets in the nuclear industry. In the case of the LOCA or RIA happen, a temperature may locally reach high values. Even if the high temperature maintains shortly, the zirconium oxides may become permeable, absorb hydrogen appearing in cooling water from decomposition reaction and crack because of formation and brittle failure of hydrides. Such model cannot so far take into...
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Endothelial dysfunction due to eNOS uncoupling: molecular mechanisms as potential therapeutic targets
PublicationNitric oxide (NO) is one of the most important molecules released by endothelial cells, and its antiatherogenic properties support cardiovascular homeostasis. Diminished NO bioavailability is a common hallmark of endothelial dysfunction underlying the patho‑ genesis of the cardiovascular disease. Vascular NO is synthesized by endothelial nitric oxide synthase (eNOS) from the substrate L‑arginine (L‑Arg), with tetrahydrobiopterin...
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The Synergistic Microbiological Effects of Industrial Produced Packaging Polyethylene Films Incorporated with Zinc Nanoparticles
PublicationZinc compounds in polyolefin films regulate the transmission of UV-VIS radiation, affect mechanical properties and antimicrobial activity. According to hypothesis, the use of zinc- containing masterbatches in polyethylene films (PE) with different chemical nature—hydrophilic zinc oxide (ZO) and hydrophobic zinc stearate (ZS)—can cause a synergistic effect, especially due to their antimicrobial properties. PE films obtained on an...
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Warstwy funkcjonalne tlenkowych ogniw paliwowych
PublicationIn this paper, results describing current research on solid oxide fuel cells conducted at Gdańsk University of Technology, Faculty of Electronics, Telecommunications and Informatics are presented. The results are related to three kinds of functional layers: a thin cathode layer between the porous cathode layer and the electrolyte to improve the cathode performance, a buffer layer between the electrolyte and the cathode to slow...
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Application of multisine nanoscale impedance microscopy to heterogeneous alloy surface investigations
PublicationIn the recent years atomic force microscopy is recognized as valuable tool for investigation of surficial features of construction materials. It concerns, among other things, studies of changes caused by such phenomena as galvanic corrosion, passivation associated with the growth of oxide layers, or sensitization of austenitic steels with the formation of carbide phases. In addition, atomic forcemicroscopy allows easy coupling...
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Effect of the Post-Weld Surface Condition on the Corrosion Resistance of Austenitic Stainless Steel AISI 304
PublicationSurfaces of welded elements made of corrosion-resistant (stainless) steels develop temper colours. The removal of thickened oxide layers off steels exposed to temperatures below 300°C is necessary and entails the restoring of high corrosion resistance of the stainless steel. The article presents tests concerned with the effect of a method applied to remove post-weld temper on the corrosion resistance of austenitic stainless steel...
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Insightful Analysis of Phenomena Arising at the Metal|Polymer Interphase of Au-Ti Based Non-Enzymatic Glucose Sensitive Electrodes Covered by Nafion
PublicationThis paper focuses on the examination of glucose oxidation processes at an electrode material composed of gold nanoparticles embedded in a titanium template. Three dierent conditions were investigated: the chloride content in the electrolyte, its ionic conductivity and the presence of a Nafion coating. The impact of the provided environment on the oxidation reaction was evaluated by cyclic voltammetry (CV) and electrochemical impedance...
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Electrochemically directed biofunctionalization of a lossy-mode resonance optical fiber sensor
PublicationIn this work, we present a direct electrochemical biofunctionalization of an indium-tin-oxide-coated lossy-mode resonance optical fiber sensor. The functionalization using a biotin derivative was performed by cyclic voltammetry in a 10 mM biotin hydrazide solution. All stages of the experiment were simultaneously verified with optical and electrochemical techniques. Performed measurements indicate the presence of a poly-biotin...
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High temperature proton conduction in LaSbO4
PublicationLanthanum orthoantimonate was synthesized using a solid‐state synthesis method. To enhance the possible protonic conductivity, samples with the addition of 1 mol% Ca in La‐site, were also prepared. The structure was studied by the means of X‐ray diffraction, which showed that both specimens were single phase. The materials crystallized in the space group P2 1 /n. Dilatometry revealed that material expands non‐linearly with the...
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Crossover from charge density wave stabilized antiferromagnetism to superconductivity in Nd1−xLaxNiC2 compounds
PublicationThe path from the charge density wave antiferromagnet NdNiC2 to the noncentrosymmetric superconductor LaNiC2 is studied by gradual replacement of Nd by La ions. The evolution of physical properties is explored by structural, magnetic, transport, magnetoresistance, and specific heat measurements. With the substitution of La for Nd, the Peierls temperature is gradually suppressed, which falls within the BCS mean-field relation for...
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The interaction of the pulsed laser irradiation with titania nanotubes - Theoretical studies on the thermal effect
PublicationThis paper reports temperature dispersion simulations of titania nanotubes irradiated by the 355 nm, pulsed, nanosecond laser. The modelling with the use of Finite Elements Method concerns titania nanotubes of the length and the wall thickness in the range of 0.5–2 μm and 5–20 nm, respectively. The uniqueness of the morphology was preserved by ensuring the wall thickness variation along the height of the tube, which was determined...
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Experimental study on the effect of selected sterilization methods on mechanical properties of polylactide FFF specimens
PublicationPurpose: Biodegradable polymers are widely used in personalized medical devices or scaffolds for tissue engineering. The manufacturing process should be finished with sterilization procedure. However, it is not clear how the different sterilization methods have an impact on the mechanical strength of the three-dimensional (3D)-printed parts, such as bone models or personalized mechanical devices. This paper aims to present the...
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Cement kiln dust
PublicationThe volume of cement production in the world has remained at the level of approxi mately 4.1 billion tons/year. The cement production process is energy intensive and is the world’s leading emitter of carbon dioxide. Therefore, the main activities cement plants are aimed at introducing technologies changes in production of clinkier.The construction industry is responsible for the majority of CO2 emissions to the atmosphere: the...