Search
Filters
total: 2120
filtered: 1749
displaying 1000 best results Help
Search results for: UV-VIS SPECTROSCOPY
-
Effect of ectoine on hydration spheres of peptides–spectroscopic studies
PublicationIn this paper, we use FTIR spectroscopy to characterize the hydration water of ectoine, its interactions with two peptides–diglycine and NAGMA, and the properties of water molecules in the hydration spheres of both peptides changed by the presence of the osmolyte. We found that the interaction of ectoine with the peptide hydration shells had no effect on its own hydration sphere. However, the enhanced hydration layer of the osmolyte...
-
Determination of phenylbutazone, sulfamethazine, carbendazim and linuron using a novel pine bark biosorbent for solid-phase extraction (SPE) with high-performance liquid chromatography (HPLC)
PublicationThe paper presents a novel pine bark based biosorbent for solid-phase extraction (SPE). The morphology and composition of the pine bark were characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The biosorbent was used for the preparation of wastewater for the determination of phenylbutazone, sulfamethazine, carbendazim, and linuron by high performance liquid chromatography with...
-
Comparison of different advanced oxidation processes for the degradation of room temperature ionic liquids
PublicationZbadano możliwość zastosowania wybranych zaawansowanych technologii utleniania (UV, UV/H2O2, UV/TiO2) do degradacji cieczy jonowych. Do degradacji wytypowano pięć związków: HHiM, BMiM, MiM, OMiM oraz EEiM.
-
Ultrasound-assisted wet-impregnation of Ag–Co nanoparticles on cellulose nanofibers: Enhanced catalytic hydrogenation of 4-nitrophenol
PublicationIn this study, a novel nanocomposite of bimetallic Ag–Co nanoparticles supported on cellulose nanofibers (CNFs) was synthesised using the ultrasound-assisted wet-impregnation method for catalytic applications. CNFs were prepared from cellulose acetate using the electrospinning technique. Fourier transform infrared spectroscopy (FTIR) analysis confirmed the successful synthesis of CNFs. Further, scanning electron microscopy (SEM)...
-
The influence of intermolecular correlations on the infrared spectrum of liquid dimethyl sulfoxide
PublicationDimethyl sulfoxide (DMSO) is routinely applied as an excellent, water-miscible solvent and chemical reagent. Some of the most important data concerning its liquid structure were obtained using infrared (IR) spectroscopy. However, the actual extent of intermolecular correlations that connect the isolated monomer spectrum to the IR response of the bulk liquid is poorly studied thus far. Using ab initio molecular dynamics (AIMD) simulations,...
-
Stopniowa chromatografia cienkowarstwowa w normalnych układach faz (NP-TLC), jako technika rozdzielania i oceny składu grupowego frakcji asfaltenowych z utleniania pozostałości próżniowej ropy naftowej
PublicationW pracy opisano wyniki badań nad opracowaniem metodyki oceny składu grupowego i czystości frakcji asfaltenowych techniką chromatografii cienkowarstwowej w normalnych układach faz (NP-TLC). Skupiono się na doborze takich parametrów/warunków rozdzielania, jak stężenie i masa próbki, a także skład i kolejność eluentów stosowanych podczas rozwijania chromatogramów TLC. Zastosowana trój-stopniowa metodyka polega na nałożeniu 5 µL frakcji...
-
A new simple approach to prepare rare-earth metals-modified TiO2 nanotube arrays photoactive under visible light: Surface properties and mechanism investigation
PublicationApplication of Ti90RE10 alloys (RE = Ho, Er, Nd, Y, Ce, Tm) as a working electrode, instead of Ti pure foil in anodic oxidation in a fluoride-based electrolyte, resulted in formation of well-ordered nanotubes made of TiO2 and RE2O3 mixture, which could be efficiently used for pollutant removal from water and air phase upon UV and visible irradiation and easily separable from the reaction mixture to recycle. The as-prepared NTs...
-
Decolorisation of Methylene Blue with Sodium Persulfate Activated with Visible Light in the Presence of Glucose and Sucrose
PublicationThe paper presents the results of research on the methylene blue (MB) degradation with sodium persulfate (PDS) activated with visible light (Vis) in the presence of glucose and sucrose. The following test were examined: absence and presence of sugars in concentrations of 50–300 mM, presence and absence of Vis radiation, pH of the model solution (6.0–12.0), identification of free radicals, kinetics of the pseudo-first-order reaction....
-
Gold(III) complexes with chloride and cyanopyridines: Facilitated hydrolysis of nitrile ligand to amide and antibacterial activity
PublicationA range of novel simple gold(III) compounds has been synthesized in their monocrystalline form, including two previously unknown chloro-complexes of Au3+ with 2-cyanopyridine or 3-cyanopyridine, respectively. Our investigations have revealed the intricate nature of the reaction between 2-cyanopyridine and tetrachloroauric acid, yielding at least three distinct products. The main product, obtained in high yield, is a salt featuring...
-
Asfalteny jako fazy stacjonarne w chromatografii cieczowej w normalnych układach faz
PublicationRozprawa doktorska dotyczy zbadania możliwości wykorzystania asfaltenów wydzielonych z: próżniowej pozostałości ropy naftowej, produktów jej utleniania i naturalnego asfaltu jako fazy stacjonarnej na powierzchni sorpcyjnej żelu krzemionkowego do rozdzielania nisko polarnych organicznych związków chemicznych w warunkach chromatografii cieczowej w normalnych układach faz, w odniesieniu do żelu krzemionkowego jako nośnika. Opracowano...
-
Ellipsometric investigation of nitrogen doped diamond thin films grown in microwave CH4/H2/N2 plasma enhanced chemical vapor deposition
PublicationThe influence of N2 concentration (1%–8%) in CH4/H2/N2 plasma on structure and optical properties of nitrogen doped diamond (NDD) films was investigated. Thickness, roughness, and optical properties of the NDD films in the VIS–NIR range were investigated on the silicon substrates using spectroscopic ellipsometry. The samples exhibited relatively high refractive index (2.6 6 0.25 at 550 nm) and extinction coefficient (0.05 6 0.02...
-
Computed vibrational excitation ofCF4by low-energy electrons and positrons: Comparing calculations and experiments
PublicationQuantum calculations for the excitation of the asymmetric modes of the CF4 target gas, ν3 and ν4, by impact of low-energy electrons and positrons are carried out in the energy range around 1 eV and are compared with recent experimental findings. The similarities and differences between the two types of projectiles, and the two different modes, are analyzed and discussed vis à vis the present accord with the experimental results.
-
Effect of irradiation intensity and initial pollutant concentration on gas phase photocatalytic activity of TiO2 nanotube arrays
PublicationWell-organized TiO2 nanotube arrays were fabricated via one-step anodization process. The as-prepared TiO2 nanotubes were characterized by X-ray powder diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectroscopy (DRS) and scanning electron microscopy (SEM). Photocatalytic activity of obtained photocatalyst was studied in reaction of toluene degradation in the gas phase using low powered and low...
-
Simultaneous opto-electrochemical monitoring of carbamazepine and its electro-oxidation by-products in wastewater
PublicationThe growing human impact on aquatic environments, due to the extensive use of pharmaceuticals and the release of persistent pollutants, makes it necessary to implement new widespread methods for the characterisation and quantification of such contaminants and relative degradation products. Carbamazepine, 5H-dibenzo[b,f]azepine-5-carboxamide, (CBZ) is a widely used anti-epileptic drug, characterised by its limited removal by conventional...
-
Chemical and biological stability of polyene macrolides
PublicationThe polyene macrolide antibiotics have been used in an-tifungal therapy since first o f them were discovered in 1950's. Up to now, four polyene macrolides are being used in medical practice, namely amphotericin B, nystatin, candi-cidin and pimaricin.The antifungal activity and mode of ac-tion of polyene macrolides is determined by their structure, chemical and physical properties.The main fragment of polyene...
-
Advanced oxidation treatment of Pentoxifylline in aqueous solution
PublicationThe degradation of pentoxifylline (PTX) using H2O2, UV, H2O2/UV, Fenton and photo- Fenton processes has been examined in aqueous solution. The influence of various amount of oxidation agent on H2O2, H2O2/UV, Fenton and photo-Fenton reactions were investigated. Initial PTX concentration in Fenton and photo-Fenton was considerated. The addition of inorganic ions (Cl-, NO3-, SO42- and CO32-) on the degradation efficiency of PTX were...
-
Chemometric Method of Spectra Analysis Leading to Isolation of Lysozyme and CtDNA Spectra Affected by Osmolytes
PublicationW niniejszej pracy zaprezentowana została chemometryczna metoda analizy danych widmowych, prowadząca do wyizolowania widm FTIR biomakrocząsteczek (lizozymu z białka jaja kurzego i ctDNA) zaburzonych przez wybrane osmolity (TMAO, betainę) w roztworach wodnych. Została ona oparta na metodzie widm różnicowych, wykorzystywanej pierwotnie do określania struktury rozpuszczalnika wokół cząsteczek substancji rozpuszczonej. Cykliczne wykorzystanie...
-
Polyurethane Nanocomposites Containing Reduced Graphene Oxide, FTIR, Raman, and XRD Studies
PublicationRecently, graphene and other graphene-based materials have become an essential part of composite science and technology. Their unique properties are not only restricted to graphene but also shared with derivative compounds like graphene oxide, reduced graphene oxide, functionalized graphene, and so forth. One of the most structurally important materials, graphene oxide (GO), is prepared by the oxidation of graphite. Though removal...
-
FT-IR studies of molecular interactions in formamide-methanol mixtures
PublicationTechniką ATR zmierzono widma FT-IR roztworów metanolu(MeOH) i formamidu(FA) w całym zakresie ich składu. Przeprowadzono analizę faktorową widm, która wykazała obecność dwóch kompleksów molekularnych matanolu z formamidem. Na podstawie profilów stężeniowych indywiduów absorbujących wyznaczono średni skład kompleksów w zależności od składu mieszaniny. Przeprowadzono również analizę pasma CO formamidu metodą widm różnicowych. Wyniki...
-
Chemometric determination of solute-affected solvent vibrational spectra as a superior way of information extraction on solute solvation phenomena
PublicationW pracy zaprezentowano dwie chemometryczne metody wyznaczania widm zaburzonych rozpuszczalnika oraz liczby cząsteczek zaburzonych, na podstawie zmierzonych serii wibracyjnych widm FT-IR roztworów substancji. Pierwsza z metod została stworzona na podstawie Namiarowej Analizy Faktorowej (ang. Target Factor Analysis). Druga z nich wykorzystuje algorytm izolacji widm czystych składników z serii widm mieszanin. Działanie obu metod zostało...
-
Application of polyethylene glycol-coated iron oxide nanoparticles for magnetic solid phase extraction of copper from seawater samples and its determination by graphite furnace atomic absorption spectrometry using response surface methodology for optimization of extraction
Publication -
Stabilization of N-, N,N-, N,N'-Methylated and Unsubstituted Simple Amidine Salts by Multifurcated Hydrogen Bonds
PublicationIn the light of the usefulness of amidines in medicinal chem., this paper considers the effects on biol. properties and chem. reactivities of org. mols. affected by intramol. interactions. The study of chem. shifts has been an important source of information on the electronic structure of amidine salts and their ability to form non-covalent bonds with nucleic acids. The NMR and IR results demonstrate that hydrogen bonds are...
-
Towards spectroscopic monitoring of photoelectrodes: In-situ Raman photoelectrochemistry of a TiO2/prussian blue photoanode
PublicationHere, novel in-situ Raman photoelectrochemical measurements are performed. The obtained results have proved that it is possible to track the progress of a photoelectrochemical reaction that takes place on a semiconducting electrode using the spectroscopic method. As an exemplary system, the Ti/TiO2/Prussian blue electrode is investigated. Since TiO2 is an n-type semiconductor, it cannot act as an efficient anode in dark conditions....
-
The effect of gold shape and size on the properties and visiblelight-induced photoactivity of Au-TiO2
PublicationtIn the present investigation, TiO2modified with a different geometry and size of gold particles, suchas nanospheres (NSPs), nanostars (NSTs) and nanorods (NRs), were prepared by the immobilizationmethod. The effect of the gold shape, size and TiO2matrix type (TiO2microspheres or rutile TIO-6 TiO2)were systematically investigated. The obtained photocatalysts were thoroughly characterized by UV–visdiffuse-reflectance spectroscopy...
-
Investigation of biological and photochemical treatment of municipal landfill leachates
PublicationW pracy przedstawiono rezultaty badań charakterystyki oraz efektywności foto- oraz biodegradacji odcieków z dwóch składowisk komunalnych w północnej Polsce. Celem pracy było zbadanie efektywności oczyszczania w systemie UV, UV/H2O2 oraz możliwości biologicznego oczyszczania odcieków metodą osadu czynnego. Stosowanie metody kombinowanej (UV/H2O2/osad czynny) pozwoliło na uzyskanie lepszej efektywności oczyszczania (98% spadek wartości...
-
Nanocrystalline CVD Diamond Coatings on Fused Silica Optical Fibres: Optical Properties Study
Publicationpre-treatment by dip coating in two detonation nanodiamond (DND) seeding media has been studied. The DND suspension in ethyl alcohol and dispersion of DND in dimethyl sulfoxide (DMSO) with polyvinyl alcohol (PVA) were chosen for the seeding purpose. The grain size distribution of nanodiamond particles in both seeding media was kept at the same level (approximately 1050 nm). After the seeding nanocrystalline diamond lms were deposited...
-
Low-energy positron scattering from gas-phase uracil
PublicationQuantum scattering calculations are presented for the interaction of low energy positrons with the uracil molecule, an important component of biological systems. The rotational elastic and inelastic cross sections and vibrational inelastic cross sections are reported and compared with existing experiments, indicating a general trend of the cross sections different from the experimental findings and in line with what should be expected...
-
Persulfates to degrade a mixture of dyes (rhodamine B, methylene blue) in the presence of glucose and visible light
PublicationA treatment process utilizing visible-light-activated (Vis) persulfates (PS) in the presence of an organic promoter (glucose) was developed for the simultaneous decolorization of a rhodamine B (RhB) and methylene blue (MB) mixture. Various doses of glucose, PS concentrations, pH values, initial dye concentrations and process time were tested to find out the most appropriate parameters for degrading the RhB/MB mixture in the...
-
An O ( n log n ) algorithm for finding edge span of cacti
PublicationLet G=(V,E) be a nonempty graph and xi be a function. In the paper we study the computational complexity of the problem of finding vertex colorings c of G such that: (1) |c(u)-c(v)|>=xi(uv) for each edge uv of E; (2) the edge span of c, i.e. max{|c(u)-c(v)|: uv belongs to E}, is minimal. We show that the problem is NP-hard for subcubic outerplanar graphs of a very simple structure (similar to cycles) and polynomially solvable for...
-
Radio- and photosensitization of DNA with compounds containing platinum and bromine atoms
Publication. Irradiations of plasmid DNA by both X-rays and UV light in the presence and absence of compounds containing platinum and bromine atoms were performed in order to asses the sensitization potential of these compounds. Plasmid DNA pBR322 was incubated with platinum (II) bromide, hydrogen hexabromoplatinate (IV), hydrogen hexahydroxyplatinate (IV) and sodium hexahydroxyplatinate (IV). Incubation was followed by X-ray or UV irradiations....
-
Anti-plane surface waves in media with surface structure: Discrete vs. continuum model
PublicationWe present a comparison of the dispersion relations derived for anti-plane surface waves using the two distinct approaches of the surface elasticity vis-a-vis the lattice dynamics. We consider an elastic half-space with surface stresses described within the Gurtin–Murdoch model, and present a formulation of its discrete counterpart that is a square lattice half-plane with surface row of particles having mass and elastic bonds different...
-
NUTRITIONAL AND PHARMACEUTICAL APPLICATIONS OF BIOACTIVE COMPOUNDS IN TROPICAL FRUITS
PublicationDuring the past two decades our international scientific group investigated in vitro the physicochemical and nutritional characteristics of some cultivars of durian at various stages of ripening, mangosteen and new cultivars of snake fruit in comparison with widely used avocado, kiwifruit and mango, and in vivo their influence on laboratory animals. The main objective of the present study was to screen and compare the properties...
-
Optimal backbone coloring of split graphs with matching backbones
PublicationFor a graph G with a given subgraph H, the backbone coloring is defined as the mapping c: V(G) -> N+ such that |c(u)-c(v)| >= 2 for each edge uv \in E(H) and |c(u)-c(v)| >= 1 for each edge uv \in E(G). The backbone chromatic number BBC(G;H) is the smallest integer k such that there exists a backbone coloring with max c(V(G)) = k. In this paper, we present the algorithm for the backbone coloring of split graphs with matching backbone.
-
Dynamics of productivity in higher education: cross-european evidence based on bootstrapped Malmquist indices
PublicationAbstract This study examines patterns of productivitychange in a large set of 266 public higher educationinstitutions (HEIs) in 7 European countries across the timeperiod 2001-2005. We adopt consistent bootstrap estimationprocedures to obtain confidence intervals for Malmquistindices of HEI productivity and their components.Consequently, we are able to assess the statistical significanceof changes in HEI productivity, efficiency...
-
Dlaczego w miarę upływu czasu wydruki cyfrowe tracą jakość. Część II
PublicationW artykule omówiono podstawy teoretyczne zabezpieczenia wydruków atramentowych przed szkodliwym wpływem promieniowania UV i czynników atmosferycznych.
-
Dlaczego w miarę upływu czasu wydruki cyfrowe tracą jakość. Część I
PublicationW artykule omówiono podstawy teoretyczne zabezpieczenia wydruków atramentowych przed szkodliwym wpływem promieniowania UV i czynników atmosferycznych.
-
Dlaczego w miarę upływu czasu wydruki cyfrowe traca jakość. Część III
PublicationW artykule omówiono podstawy teoretyczne zabezpieczenia wydruków atramentowych przed szkodliwym wpływem promieniowania UV i czynników atmosferycznych.
-
Photo-oxidation of dissolved cyanide using TiO2 catalyst
PublicationZbadano utlenianie katalityczne jonów cyjankowych w układzie UV/TiO2. Szybkość utleniania zbadano dla różnego stężenia początkowego CN-, wartość pH, formy katalizatora, temperatury oraz wprowadzanej formy gazowej. Stwierdzono że szybkość degradacji cyjanków w układzie UV/TiO2/O2 wzrasta dwukrotnie, jakkolwiek jest niezależna od ciśnienia cząstkowego tlenu (0,2-1,0 atm.). Wzrost temperatury środowiska reakcji w zakresie od 20 do...
-
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...
-
Die Sandgrube „Köplitz“ – ein interessanter geologischer Aufschluss am Nordwestrand der Schmiedeberger Stauchendmoräne
PublicationDie Kiessandgrube Köplitz ermöglicht einen Einblick in die komplizierten, durch glazidynamische Überprägung gekennzeichneten geologischen Lagerungsverhältnisse im Bereich der Schmiedeberger Stauchendmoräne. Anhand neuer Geländedokumentationen wird ein kleiner Eindruck vom komplizierten injektiven „Fließfalten-Schuppenbau“ der Stauchendmoräne vermittelt. Die steil aufgerichteten, aus tertiären (Untermiozän bis Oligozän) und quartären...
-
How do personality traits influence Open Government Data (OGD) adoption and usage? Investigating the indirect and moderating effects
PublicationOpen Government Data (OGD) research has focused for a long on the adoption and usage from the perspectives of users across different contexts. The underlying rationale for this specific focus is that OGD initiatives are undertaken to further citizen engagement with OGD for value generation and innovation purposes. Conceding that usage propensity is different across individuals, it is important to understand the influence of personality...
-
Electron Density from Balmer Series Hydrogen Lines and Ionization Temperatures in Inductively Coupled Argon Plasma Supplied by Aerosol and Volatile Species
Publication -
Nonradiative excitation energy transport and its analysis in concentrated systems
PublicationW pracy przedstawiono analizę transportu energii w roztworach dwuskładnikowych. Porównano wyniki pomiarów z modelem hoppingowym i diagramatycznym oraz z wynikami symulacji Monte Carlo. Stwierdzono dobrą zgodność wyników eksperymentalnych z przewidywaniami teorii i symulacjami komputerowymi.
-
Optical and electrical properties of ultrathin transparent nanocrystalline boron-doped diamond electrodes
PublicationThe optical properties of ultrathin (less than 100 nm) boron-doped nanocrystalline diamond (B-NCD) film were investigated in a wavelength range of 200 ÷ 20000 nm. The B-NCD refractive index showed values close to that of monocrystalline diamond (n = 2.45) in a broad wavelength range (450 ÷ 4000 nm). A transmittance up to 70% and the average film thickness of 70 nm were achieved. A special cone-shaped shim was used in the deposition...
-
Nanostructuring of thin Au films deposited on ordered Ti templates for applications in SERS
PublicationIn this work the results on thermal nanostructuring of the Au films on Ti templates as well as morphology and optical properties of the obtained structures are reported. The bimetal nanostructures are fabricated in a multi-step process. First, the titania nanotubes are produced on the surface of Ti foil by anodization in an ethylene glycol-water solution containing fluoride ions. This is followed by chemical etching in oxalic acid...
-
Synthesis of Titanium Dioxide via Surfactant-Assisted Microwave Method for Photocatalytic and Dye-Sensitized Solar Cells Applications
PublicationIn this study, titania nanoparticles were obtained using the microwave-assisted technique. Moreover, different surfactants (PEG (Mn = 400), Pluronic P123 and Triton X−100) were used during the synthesis in order to determine their impact on the crystallinity and morphology of the final products. Subsequently, techniques such as XRD, SEM and TEM (performed in high contrast and high-resolution mode), diffuse reflectance spectroscopy...
-
Investigation into the Effect of Spinel Pigments on the Photostability and Combustion Properties of Ethylene-Norbornene Copolymer
PublicationMulticolor ethylene-norbornene (EN) composites filled with three different spinel pigments (Cobalt Green-PG50, Zinc Iron Yellow-PY 119, Praseodym Yellow-PY159) were prepared by melt mixing and characterized in terms of their stability under destructive environmental conditions. The EN films were subjected to accelerated aging by ultraviolet (UV) photooxidation for 300 h, 600 h, or 900 h. The mechanical performance of the EN composites...
-
In-Out Surface Modification of Halloysite Nanotubes (HNTs) for Excellent Cure of Epoxy: Chemistry and Kinetics Modeling
PublicationIn-out surface modification of halloysite nanotubes (HNTs) has been successfully performed by taking advantage of 8-hydroxyquinolines in the lumen of HNTs and precisely synthesized aniline oligomers (AO) of different lengths (tri- and pentamer) anchored on the external surface of the HNTs. Several analyses, including FTIR, H-NMR, TGA, UV-visible spectroscopy, and SEM, were used to establish the nature of the HNTs’ surface engineering....
-
Nucleation and growth of CVD diamond on fused silica optical fibres with titanium dioxide interlayer
PublicationNucleation and growth processes of thin diamond films on fused silica optical fibres have been investigated. Fibres were coated with diamond film using microwave plasma enhanced chemical vapour deposition (µPE CVD) system. Since the growth of diamond on the fused silica glass requires high seeding density, two types of glass pre-treatment were applied: titanium dioxide (TiO2) interlayer deposition and sonication in nanodiamond...
-
Możliwości dezynfekcji biologicznie oczyszczonych ścieków na przykładzie oczyszczalni ścieków "Wschód" w Gdańsku
PublicationWyniki badań dezynfekcji biologicznie oczyszczonych ścieków z oczyszczalni "Wschód" w Gdańsku. Badania z wykorzystaniem trzech technologii dezynfekcji: ozonowania, promieniowania UV oraz mikrofiltracji. Rola badań kontrolnych.