wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: spetroscopy
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Frequency Diagnostics of Transformer Insulating Parameters
PublikacjaIn the article is presented experimental analysis and diagnostics of insulating system oil-paper for power transformers, mainly by progressive frequency method – dielectric spectroscopy. In the 1-st part of the article is described base theory about measurement and diagnostics insulating part (oil and paper) of power transformers. In the 2-nd part of article is described measuring method of insulating frequency diagnostics - frequency...
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The Effect of Sodium Tetrafluoroborate on the Properties of Conversion Coatings Formed on the AZ91D Magnesium Alloy by Plasma Electrolytic Oxidation
PublikacjaMagnesium and its alloys are widely used in many areas because of their light weight, excellent dimensional stability, and high strength-to-weight ratio. However, the material exhibits poor wear and corrosion resistance, which limits its use. Plasma electrolytic oxidation (PEO) is an effective surface modification method for producing ceramic oxide layers on Mg and their alloys. The influence of the additions of sodium tetrafluoroborate...
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Photochemical Rearrangement of a 19-Membered Azoxybenzocrown: Products and their Properties
PublikacjaThe preparation and characterization of products of the chemical and photochemical rearrangements of a 19-membered o,o'-azoxybenzocrown were presented. In photochemical rearrangement, besides expected product i.e. 19-membered o-hydroxy-o,o'-azobenzocrown (19-o-OH), obtained under defined conditions with 75% yield, also other macrocyclic products were isolated and identified, namely: 19-membered p-hydroxy-o,o'-azobenzocrown (19-p-OH),...
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The Effect of Titanium Oxyfluoride Morphology on Photocatalytic Activity of Fluorine-Doped Titanium(IV) Oxide
PublikacjaTitanium oxyfluoride (TiOF2) is a metastable product that can be obtained in a fluorine-rich environment. This material can also be a valuable precursor in the synthesis of titanium(IV) oxide (TiO2). However, the effect of TiOF2 morphology on the physicochemical properties of TiO2 has not been studied so far. In this work, single-phase TiOF2 was prepared by a solvothermal method. The as-synthesized samples exhibited a variety of...
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Impedance spectra of RC model as a result of testing pulse excitation measurement method
Dane BadawczeThe impedance spectrum of RC model object obtained using pulse excitation EIS impedance spectrosocpy measurement method. The 1V voltage pulse excitation duration was set to 0.1s and the total acqusition time was set to 1000s. The object under test was built using RC components connected as Baunier model of anticorrosion coating with the following components...
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Novel decahedral TiO2 photocatalysts modified with Ru or Rh NPs: Insight into the mechanism
PublikacjaNovel decahedral TiO2 modified with Ru or Rh NPs were successfully synthesized by hydrothermal method. The effect of metal type as well as amount of noble metal precursor (0.05, 0.1, 0.2, 0.3 and 0.5 wt.%) on the photocatalytic activity were investigated. Decahedral TiO2 decorated by Ru and Rh nanoparticles was prepared by photodeposition method, whereas Rh doped TiO2 was obtained by onestep hydrothermal method with introduction...
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Synthesis, characterization and Luminescent Properties of New Coordination Polymers Based on p-tert Butylcalix[4]arene-tetracarboxylic acid and Lanthanine cations
PublikacjaA series of new coordination polymers based on p-tert-butylcalix[4]arene-tetracarboxylic acid with Eu3+, Tb3+wrer prepared by hydro and solvothermal methods. the obtained solid compounds were characterized by infrared and luminescence spectroscopy, powder X-ray diffraction, scianning electron microscopy and thermogravimetric anylisis. The infrared curves and the x-ray diffraction patterns indicate that the same crystalline structure...
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Effect of nitrogen doping on TiOxNy thin film formation at reactive high-power pulsed magnetron sputtering
PublikacjaThe paper is focused on a study of formation of TiOxNy thin films prepared by pulsed magnetron sputtering of metallic Ti target. Oxygen and nitrogen were delivered into the discharge in the form of reactive gases O2 and N2. The films were deposited by high-power impulse magnetron sputtering working with discharge repetition frequency f = 250 Hz at low (p = 0.75 Pa) and high (p = 10 Pa) pressure. The substrates were on floating...
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Preparation and characterization of monometallic (Au) and bimetallic (Ag/Au) modified-titania photocatalysts activated by visible light
PublikacjaThe Au-TiO2 and Ag/Au-TiO2 nanoparticles have been prepared using a water-in-oil microemulsion system of water/AOT/cyclohexane and water/Triton X-100/cyclohexane. The obtained photocatalysts were subsequently characterized by a BET method, DRS spectroscopy, X-ray photoelectron emission spectroscopy (XPS), scanning transmission electron microscopy (STEM) and X-ray powder diffraction analysis (XRD). For gold-doped titanium (IV) oxide...
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BASECOL2023 scientific content
PublikacjaContext. The global context of making numerous data produced by researchers available requires collecting and organising the data, assigning meaningful metadata, and presenting the data in a meaningful and homogeneous way. The BASECOL database, which collects inelastic rate coefficients for application to the interstellar medium and to circumstellar and cometary atmospheres, meets those requirements. Aims. We aim to present the...
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Preparation and characterization of Pt–N/TiO2 photocatalysts and their efficiency in degradation of recalcitrant chemicals
PublikacjaSeries of Pt–N/TiO2 photocatalysts were synthesized using the sol–gel method. The photocatalysts’ characteristics by X-ray diffractometry (XRD), scanning transmission electron microscopy (STEM), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) showed that sample with the molar ratio Ti:N equal 1:4 and platinum nanoparticles size of about 3 nm had anatase structure, about 94 m2/g specific surface area...
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Study on surface termination of boron-doped diamond electrodes under anodic polarization in H2SO4 by means of dynamic impedance technique
PublikacjaAnodic oxidation is a popular way to modify termination bonds at boron doped diamond electrodes altering their electrochemical and physicochemical properties. Our studies, performed with dynamic electrochemical impedance spectroscopy technique, supported with X-ray photoelectron spectroscopy and ellipsometry analysis prove its utility in continuous on-line monitoring of impedance changes on the electrode surface under polarization...
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Enhanced photocatalytic properties of lanthanide-TiO2 nanotubes: An experimental and theoretical study
PublikacjaA series of Er-, Yb-, Ho-, Tb-, Gd-, Pr-TiO2 nanotubes (RE-NTs) was prepared via an electrochemical method. The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–vis absorption, scanning electron microscopy (SEM) and luminescent spectroscopy. The experiments demonstrated that toluene in the gas phase was successfully degraded under visible light (LEDs λmax = 465...
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Deposition and characterization of organic polymer thin films using a dielectric barrier discharge with different C2Hm/N2 (m = 2, 4, 6) gas mixtures
PublikacjaOrganic polymer thin films have been deposited on Si(100) and aluminum coated glass substrates by a dielectric barrier discharge (DBD) operated at medium pressure using different C2Hm/N2 (m = 2, 4, 6) gas mixtures. The deposited films were characterized by various spectroscopic techniques. Fourier transform infrared reflection absorption spectroscopy (FT-IRRAS) revealed the chemical functional groups present in the films. The surface...
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Quantitative assessment of the main antioxidant compounds, antioxidant activities and FTIR spectra from commonly consumed fruits, compared to standard kiwi fruit
PublikacjaBioactive compounds (polyphenols and ascorbic acid) and dietary fibers, and related antioxidant activities of commonly consumed apples, bananas, peaches, pears, blond and red grapefruits, pomelos, oranges, lemons, red plums, white grapes, mango, persimmon and strawberries grown in the same geographical and climatic conditions were compared with standard kiwi fruit. The presence of polyphenols was studied by Fourier transform infrared...
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Unsaturated, biobased polyesters and their cross-linking via radical copolymerization
PublikacjaBiobased, unsaturated polyesters derived from isosorbide, maleic anhydride and succinic acid were synthesized and characterized. The presence of maleic anhydride units in the structure of the polyesters allowed converting them into cured coatings by radical copolymerization with cross-linking agents such as 2-hydroxyethyl methacrylate, N-vinyl-2-pyrrolidinone, acrylic acid or methacrylamide. The investigated polyesters were obtained...
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Correlation between partial inhibition of hydrogen evolution using thiourea and catalytic activity of AB5-type hydrogen storage alloy towards borohydride electrooxidation
PublikacjaDirect borohydride fuel cells (DBFCs) are devices which directly convert the chemical energy stored in the borohydride ion and oxidant into electrical energy as a result of redox reactions. Unfortunately, a significant amount of fuel is lost as a result of the undesirable hydrolysis reaction. The selection of an efficient borohydride hydrolysis inhibitor requires detailed knowledge regarding the interaction mechanism between the...
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FTIR spectroscopic and thermogravimetric characterization of ground tyre rubber devulcanized by microwave treatment
PublikacjaIn this work, the phenomena involved in the microwave devulcanization of ground tyre rubber (GTR) were investigated. Three types of GTR with different content of organic compounds (elastomers, plasticizers, etc.), carbon black and ash have been studied. The chemical structure of GTR before and after a microwave devulcanization process was analyzed by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA)...
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Highly Active TiO2 Microspheres Formation in the Presence of Ethylammonium Nitrate Ionic Liquid
PublikacjaSpherical 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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Electrochemical properties of porous Sr0.86Ti0.65Fe0.35O3 oxygen electrodes in solid oxide cells: Impedance study of symmetrical electrodes
PublikacjaThis work evaluates porous Sr0.86Ti0.65Fe0.35O3 (STF35) as a possible oxygen electrode material for Solid Oxide Cells. The powder synthesis was performed by solid state method. Characterization included DC electrical conductivity study of sintered bulk samples and impedance spectroscopy study of symmetrical electrodes deposited on gadolinium doped ceria substrates. Measurements were carried out in atmospheres with different pO2...
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Impedance evaluation of coatings from biobased material
PublikacjaThe authors propose a modification of sodium caseinate edible coating for foodstuff protection. The aim was to improve the film’s barrier properties. It was achieved by the addition of propolis, which is a natural, environmentally friendly product known from its intrinsic sealing action. In the next step, propolis-admixed sodium caseinate films were exposed to elevated temperature for 10 min. This approach was meant to improve...
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Is the Solid Electrolyte Interphase an Extra-Charge Reservoir in Li-Ion Batteries?
PublikacjaAdvanced 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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Photocatalytic decolourization of Rhodamine-B dye by visible light active ZIF-8/BiFeO3 composite
PublikacjaIn this work, preparation of ZIF-8 supported BiFeO3 photocatalyst by ultrasound cavitation technique was reported. The synthesized materials were characterized using solid UV absorption spectroscopy, Raman Spectroscopy, and SEM. The catalytic function of synthesized photocatalyst under ultraviolet and visible light was examined for the decolourization of Rhodamine-B (Rh-B) dye. To understand the action of the photocatalyst on Rh-B...
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Investigation of the Few‐Layer Black Phosphorus Degradation by the Photonic Measurements
PublikacjaFew-layer black phosphorus (FLBP) is a 2D material that gains worldwide interest for its possible applications, mainly in electronics and optoelec-tronics. However, as FLBP is prone to a degradation process under envi-ronmental conditions, there is a need for a monitoring method allowing investigation of its surface quality. Among many techniques, optoelectronic ones have unique advantages of fast response, non-contact, and non-invasive...
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Experimental tuning of AuAg nanoalloy plasmon resonances assisted by machine learning method
PublikacjaPlasmonic nanostructures based on AuAg nanoalloys were fabricated by thermal annealing of metallic films in an argon atmosphere. The nanoalloys were chosen because they can extend the wavelength range in which plasmon resonance occurs and thus allow the design of plasmonic platforms with the desired parameters. The influence of initial fabrication parameters and experimental conditions on the formation of nanostructures was investigated....
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Analysis
PublikacjaNew food products and diverse formulations containing the regulated steviol glycoside(s) as well as Stevia extracts or Stevia leaves have been brought on the global market. The upcoming multitude of such food products, but also their falsification and adulteration, does have impact on food analysis. Robust high-throughput methods that cope with different food matrices are required for food control to ensure food safety. The analysis...
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Metal enhanced fluorescence of flavin mononucleotide using new plasmonic platform
PublikacjaNew plasmonic platform was successfully obtained to investigate the increase of fluorescence intensity of a fluorophore in the presence of silver nanoparticles. A flavin mononucleotide, was selected by us as a fluorophore for this study as a very important biological compound playing a key role in many biochemical process. Plasmonic platforms were characterized by means of luminescence spectroscopy. Flavin mononucleotide deposited...
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Dynamic impedance spectra of programmable dynamically changing RC model based on digital potentiometers
Dane BadawczeThe dataset presents non-stationary impedance spectra of the RC model presented in the figure below. This model contains two digital potentiometers controlled digitally by the microcontroller. This solution allows to programmably control the value of the model impedance. Thanks to this, the model can be used as a test engine for evaluation of the dynamic...
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Dynamic impedance data for various carboxylic acids corrosion inhibition of aluminium in alkaline media (pH=11)
Dane BadawczeThis dataset contains the results of Dynamic Electrochemical Impedance Spectroscopy (DEIS) carried out in galvanostatic mode under iDC=0, carried out in order to define the corrosion inhibition effect of various studied carboxylic acids: citric acid, malic acid, maleic acid, succinic acid, tartaric acid, carballylic acid, and serine. The experiment...
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Linear impedance of V2O5 nanorods obtained at 903K
Dane BadawczeThe DataSet contains the linear electrical properties of V2O5 nanorods which were measured by the impedance spectroscopy method. V2O5 nanorods were obtained by the sol-gel method. The information about xerogel powder synthesis is described in the Journal of Nanomaterials. The precursor powder was pressed into the disk-shaped pellets (12mm in diameter...
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Graphene oxide thin films deposited on a PCB board - chemical analysis
Dane BadawczeGraphene oxides based films were measured by X-ray photoemission spectroscopy (XPS) method. TheXPS measurements were carried out with the Omicron NanoTechnology UHV equipment. The hemispherical spectrophotometer was equipped with a 128-channel collector. The XPS measurements were performed at room temperature at a pressure below 1.1 × 10−8 mBar. The...
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Plasmon resonance in gold-silver nanoalloys
Dane BadawczeSurface plasmon resonance (SPR) can lead to improve or formation a new linear or nonlinear optical phenomena. Especially it can enhance a light emission from luminescence materials. The presence of metal nanostructures or nanoparticles is necessary to excitation of the SPR. It is well known that gold and silver nanostructures exhibit plasmon resonance...
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Investigation of plasmon resonance in a silver nanoparticles
Dane BadawczeSilver nanostructures were prepared on borosilicate glass (Corning 1737F) substrates. Thin Ag films (1–9 nm thickness) were deposited using a table-top dc magnetron sputtering coater (EM SCD 500, Leica) in pure Ar plasma (argon, Air Products 99.999%). The Ag target was of 99.99% purity, the rate of layer deposition was about 0.4 nm·s−1, and the incident...
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Study of the chemical state of Gd in a Ba-La-Gd-Co based ceramic
Dane BadawczeBarium, Lanthanum, Gadolinium and Cobaltium precursors were used for production of ceramic materials. Samples were produced by standard solid state reaction. Samples were annealed at 300 Celsius degree in wet and dry atmosphere. Annealing takes 72h or 2h. Results of annealing on a Gadolinum were observed by X-Ray photoemission spectroscopy (XPS), OmicronNanotechnology....
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Linear impedance of V2O5 nanorods obtained at 913K
Dane BadawczeThe DataSet contains the linear electrical properties of V2O5 nanorods which were measured by the impedance spectroscopy method. V2O5 nanorods were obtained by the sol-gel method. The information about xerogel powder synthesis is described in the Journal of Nanomaterials. The precursor powder was pressed into the disk-shaped pellets (12mm in diameter...
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Linear impedance of V2O5 nanorods obtained at 893K
Dane BadawczeThe DataSet contains the linear electrical properties of V2O5 nanorods which were measured by the impedance spectroscopy method. V2O5 nanorods were obtained by the sol-gel method. The information about xerogel powder synthesis is described in the Journal of Nanomaterials. The precursor powder was pressed into the disk-shaped pellets (12mm in diameter...
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Synthesis of Novel Polycationic Quaternary Di- and Trispirocyclic Benzenes
PublikacjaTreatment of hexakis(bromomethyl)benzene with a cyclic amine {morpholine, 1-methylpiperazine, 1-(2-hydroxyethyl)piperazine, isonipecotamide, 4-hydroxypiperidine, 4-[3-(4-piperidyl)propyl]-1-piperidineethanol} gave a range of di- and trispirocyclic ammonium salts in satisfactory yields (22-62%). Presumably, the electrostatic and repulsion forces play an important role in their formation. The structure in soln. and the protonation...
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Sport-related concussion alters cerebral hemodynamic activity during controlled respiration
PublikacjaThis study investigated cerebral hemodynamic activity following sport-related concussion. Prefrontal cortex oxygenation was assessed by near-infrared spectroscopy (NIRS) during a controlled breathing protocol. Wavelet transformation of the NIRS signals showed significant decreases in HbO2 and HbD amplitude at the respiratory frequency interval (0.10–0.6 HZ) from preseason baseline to acute concussion. These results suggest a decreased...
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Simultaneous impedance and volumetric studies and additionally potentiodynamic polarization measurements of molasses as a carbon steel corrosion inhibitor in 1M hydrochloric acid solution
PublikacjaThe inhibition effect of molasses on the corrosion of low carbon steel in 1M hydrochloric acid solution was investigated by volumetric and electrochemical measurements. Potentiodynamic polarization and dynamic electrochemical impedance spectroscopy (DEIS) results were obtained and compared with to those, obtained with the hydrogen evolution technique. All results indicate that molasses functioned as a good inhibitor in 1M hydrochloric...
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Absolute configurations of C34 and C35 of antibiotic niphimycin A
PublikacjaThe relative configurations of four stereogenic centers of the C33-C42 fragment of niphimycin A were assigned as 2S*, 3R*, 4S* and 6S*, based upon 1H NMR analysis with double-quantum filtered COSY and nuclear Overhauser spectroscopy experiments. These data were then correlated with absolute configurations at C36 and C38 of niphimycin A, which were declared previously as 36S and 38S [3]. This allowed for the assignment of the absolute...
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Absolute configurations of C34 and C35 of antibiotic niphimycin A
PublikacjaThe relative configurations of four stereogenic centers of the C33-C42 fragment of niphimycin A were assigned as 2S*, 3R*, 4S* and 6S*, based upon (1)H NMR analysis with double-quantum filtered COSY and nuclear Overhauser spectroscopy experiments. These data were then correlated with absolute configurations at C36 and C38 of niphimycin A, which were declared previously as 36S and 38S [3]. This allowed for the assignment of the...
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Cross-linked epoxy-isocyanate blends containing Epidian-6 modified by glycols
PublikacjaPolymeric films of cross-linked structure may be formed using epoxy-isocyanate blends composed of Epidian-5 epoxy resin, 4,4’-diphenylmethanediisocyanate (MDI), Z-1 polyamine hardener and Epidian-6 epoxy resin modified by glycols. The effect of the component natures and ratio, process temperature and time on the gel-fraction content, as well as film hardness, was examined. The chemistry of the film forming process was determined...
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PREPARATION AND CHARACTERIZATION OF CoFe2O4/TiO2-PANI HYBRID NANOCOMPOSITE WITH MAGNETIC AND PHOYOCATALYTIC ACTIVITY
PublikacjaHybrid nanocomposites consisting of inorganic component and organic conducting polymer are promising materials, which can be applied in heterogeneous photocatalysis. Titanium(IV) oxide is widely used photocatalysts due to its non-toxicity, low cost and chemical stability. The main disadvantage of TiO2 is low photocatalytic activity under visible light. Conducting polymers, also known as conjugated polymers are polymer materials...
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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
PublikacjaOxynitride 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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TiO2 /SrTiO3 and SrTiO3 microspheres decorated with Rh, Ru or Pt nanoparticles: Highly UV–vis responsible photoactivity and mechanism
PublikacjaA series of TiO2/SrTiO3 and SrTiO3 microspheres decorated by Rh, Ru or Pt NPs were prepared by facile hydrothermal method. The as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) with energy-dispersive Xray (EDX) spectroscopy, scanning electron microscopy (SEM), photoluminescence spectrometry (PL), Fourier transform infrared (FT-IR) and...
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Succinite, Baltic Amber: A Chemical Masterpiece of Nature
PublikacjaSuccinite, Baltic amber, is one of the most appreciated fossil resins. Its beauty has fascinated people since prehistoric times. It is a substance, and also gemstone, whose uniqueness is due to its compelling, though still not fully understood, physicochemical nature. In this article, some facts about the physical and chemical properties of succinite in order to find an answer for questions about the unique properties of this resin,...
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Research of chitosan coatings deposited by electrophoretic deposition method at various voltage and time parameters
PublikacjaThe aim of this research is to estimate the electrophoretic deposition main parameters, such as voltage and time duration, that will provide optimal characteristics of the surface layer. Chitosan coatings were synthesized on biomedical Ti13Zr13Nb alloys at 20 V and 30 V and with deposit times of 2min, 5 min, 10 min, and 15 min. Evaluation of the coating was performed by using Scanning Electron Microscope (SEM), Energy-Dispersive...
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Extractive detoxification of hydrolysates with simultaneous formation of deep eutectic solvents
PublikacjaThe hydrolysis of lignocellulosic biomass results in the production of so-called fermentation inhibitors, which reduce the efficiency of biohydrogen production. To increase the efficiency of hydrogen production, inhibitors should be removed from aqueous hydrolysate solutions before the fermentation process. This paper presents a new approach to the detoxification of hydrolysates with the simultaneous formation of in-situ deep eutectic...
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Hydrothermal reactions: From the synthesis of ligand to new lanthanide 3D-coordination polymers
PublikacjaThe organic ligand 2,5-piperazinedione-1,4-diaceticacid (H2PDA) was synthesized under hydrothermal conditions starting from the iminodiacetic acid and catalyzed by oxalic acid. The X-ray powder diffraction data indicates that the compound crystallizes in the P21/c space group as reported in the literature. The ligand was also characterized by elemental analysis, magnetic nuclear resonance, infrared spectroscopy and thermogravimetric...
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Waterborne polyesters partially based on renewable resources
PublikacjaA new experimental approach for preparing biobased, water-soluble polyesters via titanium(IV) n-butoxide-catalyzed bulk polycondensation is presented. In the described method polymers were obtained from isosorbide, maleic anhydride and poly(ethylene glycol). The chemical structure of the synthesized polyesters was confirmed using 2D NMR spectroscopy and by titration methods. Careful analysis of 2D NMR spectra viz. Correlation Spectra...