Manganese sulphide (MnS) thin films were prepared by chemical bath deposition method. X-ray diffraction analysis was used to study the structure and the crystallite size of MnS thin films. The grain size and the surface morphology were studied using scanning electron microscopy. The optical properties were studied using the UV-visible absorption spectrum. The dielectric properties of MnS thin films were studied for different frequencies and different temperatures. Further, electronic properties, such as valence electron plasma energy, average energy gap or the Penn gap, the Fermi energy and electronic polarizability of the MnS thin films were calculated. The ac electrical conductivity study revealed that the conduction depended both on the frequency and the temperature. The temperature dependent conductivity study confirmed the semiconducting nature of the films.
This work examines the recommended chemical analytical method for the identification and detecting mercury from the environmental media. The aim of this study was to establish a correlation between mercury content in different biological indicators like: human hair, mushrooms, lichen, moss and needle samples, and the changes in the structure of the investigated material. We have explored the possibilities of using the SEM method in environmental studies to investigate a variety of biological samples coming from areas at different pollution state. We have combined the information from the quantity measurements with the qualitative analysis. The total content of Hg was determined using the Automatic Mercury Analyzer SP-3D. The accuracy of the applied method was verified by an analysis of proper certificate materials: Mixed Polish Herbs INCT-MPH-2, Lichen CRM 482, Pine needles 1575a and Human Hair NCS ZC 81002. The obtained results proved a direct influence of the content of mercury and environmental pollution on the damage of the structure of the studied samples.
The polycrystalline samples of Na1/2Y1/2TiO3 were prepared by the mixed-oxide method. A preliminary X-ray structural analysis was shown to exhibit the formation of a single-phase compound with an orthorhombic structure. Microstructural analysis by scanning electron microscopy (SEM) exhibits well defined grains distributed uniformly through out the sample suggesting the compactness and homogeneity of the sample. Detailed studies of dielectric properties of Na1/2Y1/2TiO3 in a wide frequency range (102–106 Hz) at different temperatures (31–500°C) show a dielectric anomaly at 105°C, which may be related to a ferroelectricparaelectric phase transition as suggested by hysteresis loop at room temperature. An ac conductivity (σ ac) of the material is mainly governed by the polaron hopping mechanism, which is also influenced by both frequency and temperature. The activation energy was obtained from the plot of temperature with a.c. conductivity.
Some earlier synthesized copper selenide (Cux Se) layers formed on the surface of polyamide 6 by sorption-diffusion method using potassium selenotrithionate (K2SeS2O6) as precursor of selenium were characterized by the XRD, XPS and SEM methods. According to the results of the SEM studies, the most uniform Cux Se layers form at the 2.5 h polyamide seleniumized duration at the temperature of 60°C. The thickness of layers, which dependeds on the duration of seleniumization, changed in the range of 0.8–3.2 µm. The XRD patterns of not previously studied Cux Se layers showed their phase composition of six copper selenides: Cu2Se, two phases of CuSe2, Cu3Se2, berzellianite, Cu2-x Se, and bellidoite Cu2Se. Analysis of the XRD and XPS data shows that the macrostructure and composition of the CuxSe layers depend on the conditions of formation of these layers. [...]
Formation of a silver selenide layer on silicone coated polyamide cloth was investigated. Fabric samples were selenized in potassium selenotrithionate (K2SeS2O6) solution then treated with AgNO3 solution. Formation of a silver selenide particle layer on the surface was confirmed by a change in appearance, X-ray diffraction, and EDX analysis. XRD revealed two phases: orthorhombic naumannite (Ag2Se) and monoclinic selenium (Se8). SEM showed that the fabric macrostructure and the multifilament yarn microstructure was preserved. The silver selenide particles ranged from 100 nm to more than 20 µm. [...]
The inhibition of X80 carbon steel corrosion in 1 M HCl solution by dexketoprofen (DKP) was studied using weight loss (WL), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP) and scanning electron microscopy (SEM) techniques. The results indicated that DKP acts by way of adsorption as an effective protective inhibitor in the aggressive acid medium. The inhibition efficiency of DKP increased with concentration but was lower at higher temperature. The results of potentiodynamic polarization showed that DKP molecule behaved as a mixed type inhibitor by reducing both the anodic and the cathodic electrochemical reactions. Dexketoprofen was adsorbed on the X80 steel surface in accordance with Langmuir adsorption isotherm. SEM analyses supported formation of protective film on the X80 steel in the presence of DKP.
Geopolymer structures are a relatively new family of un-fired ceramics that are produced by alkaline slurry of mixed alumina silicate-based materials. One of the most abundant geopolymer-forming powders is the fly ash. Fly ash is a waste product of thermic coal plants, which produce electricity by coal burning. Fly ashes contain mostly Ca, Al, Si and Fe oxide mixtures and compounds formed during the burning process, followed by sedimentation. The standardization is made by SiO₂ content. Class C ash has low silica content (<50 wt.%) and class F ash has a higher silica content (>50 wt.%). The fly ash, studied in this work, was obtained from Kangal Coal Plant. The NaOH was used as the geopolymer binder and curing was performed at 80% relative humidity, at 40°C in sealed plastic molds. The obtained cylinders were aged for one week before releasing from molds. pH dependent degradation was used to determine the ionic exchange of geopolymers into the solution. Afterwards, XRD and SEM were done to detect the structural changes of geopolymers.
Results on the influence of mechanoactivation (3–30 min) in a planetary ball mill on the composition, crystal structure, IR spectra and morphology of EuCl3·6H2O, dibenzoylmethane (HDBM) and mixtures of EuCl3·6H2O - HDBM and EuCl3·6H2O - HDBM - 1,10-phenathroline (phen) are presented. Mechanoactivation leads to a decrease of interplanar distances of the EuCl3·6H2O and HDBM and partial synthesis of Eu(DBM)3 and Eu(DBM)3·phen in the respective mixtures. The fluorescence properties of the products of activation (excitation and emission spectra, lifetime of the excited states) are similar to those of the complexes produced by the conventional “wet” methods, but the strongest excitation of the mechanochemically produced solid state samples is achieved at higher wavelength. Crystals of different forms (prismatic, needle-, long-length-leaf- and rod-like) are formed by mechanoactivation of the mentioned mixtures.
The paper considers the possibilities for mechanochemical synthesis of rare earth complexes. The complex Eu(TTA)3·phen (HTTA - 2-thenoyltrifluoroacetone, phen - 1,10-phenanthroline) is synthesized by mechanical treatment of a mixture of EuCl3.6H2O, HTTA, phen and NaOH in planetary ball mill Pulverisette 7 for 30 min at 800 min−1. The non reacted starting reagents and reaction side products are separated by treating activated mixture with water-ethanol solution following a procedure proposed in the literature. The elemental composition, X-ray diffraction pattern, IR spectra, optical properties (excitation and emission spectra, luminescence lifetime) and morphology of the mechanochemically synthesized complex are compared with those of the complex prepared from solution by the conventional method. The results confirm close similarity in the molecular structure and identity of the elemental composition, X-ray diffractograms and fluorescence properties of the compounds prepared by both methods. [...]
The U-Pb system is a useful chronometer for understanding the formation history of chondritic materials. Modern studies showed that the formation ages of chondrites (4.55–4.56 Ga) effectively equal the formation age of the solar system. Recently, researchers have undertaken U-Pb isotopic studies of phosphates separated from equilibrated ordinary chondrites, which are the major hosts for U and are enriched by an order of magnitude or more relative to the bulk rock (typical U concentrations of 0.1–3 ppm in phosphates). The observed Pb-Pb model ages for these phosphates range from 4.563–4.502 Ga, with an analytical precision of 1 Ma and the U-Pb system is apparently concordant. They also argued that the Pb-Pb ages of the phosphates from several H chondrites show a negative correlation with metamorphic grade. They concluded that thermal processing of the equilibrated chondrites took place over a 60 Ma interval and grain size of the phosphates increases with the degree of metamorphism. In the Leoncin meteorite, apatite reveal the 207Pb/206Pb age, which is 4549±61 Ma. The obtained apatite age in the Leoncin meteorite reflects the early solar system formation process. Moreover, the age is an example of the early solar system metamorphism, which confirms a slightly younger event of secondary changes of the parent body for this meteorite. It is also the first isotopic age of a Polish meteorite.
In this study we have investigated diamond nucleation on Si substrates by ultrasonic seeding with different liquid solutions of Ultradispersed Detonation Diamond (UDD) powder in a mixture of metal nano- or microparticles (Ni, Co, Y). The influence of different solutions on nucleation efficiency was investigated. For highlighting nucleation centers and better evaluation of the nucleation process the nucleated samples were moved into a Microwave Plasma Enhanced Chemical Vapor Deposition (MW CVD) reactor and a ”short-time” (10 min), then followed by a ”long-time” (+1 hour), diamond deposition was performed. The morphology of samples was characterized by Scanning Electron Microscopy (SEM) and the chemical composition of grown diamond layer was investigated by Raman Spectroscopy. From the measurements we found out that microsized metal particles positively influenced nucleation and the uniformity of the deposited diamond thin film. The lowest surface roughness was achieved in the case of nanodiamond powder mixed with Co and Y metal powder. The influence of Ni, Co and Y to the nucleation and early growth stage are discussed.
The morphology of silver particles deposited on ITO-glass surface by pulse electrolysis in acetonitrile solutions of AgNO3 has been analyzed. The influences of potential value (E) as well pulse duration (τon) and pause (τoff) on the size and geometry of the particles has been discussed. It has been shown that in the range of 0.0 ≤ E ≤ −1.5 V at τon = 6 ms and 90 ≤ τoff ≤ 490 ms formation of silver particles (∼20–50 nm) and their agglomeration (∼0.2–2 µm) take place. The tendency to increase size of the particles in 3D has been observed with the increase of cathode potential. Decreasing of duty cycle leads to more discrete deposited particles. [...]
Zinc oxide (ZnO) was mechanically activated in air using a planetary ball mill using varying milling speeds and time. The obtained samples were analyzed by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and UV-Vis diffusion reflectance spectroscopy. The photocatalytic activity of the mechanically treated ZnO powders were investigated in the reaction of Malachite Green (MG) degradation in aqueous solution under UV-light irradiation. A decrease in the crystallite size (from 90 to 10 nm) accompanied by an increase of microstrains and lattice parameters were established applying different milling speeds. The agglomeration of the particles was observed by SEM analysis. The absorption spectra of the initial and mechanically activated ZnO samples show shifting of the band position from 360 to 330 nm, which can be related to decrease in the crystalline size. The ZnO powders activated at lower milling speeds (for shorter time intervals) exhibit highest photocatalytic activity. [...]
Novel cryogels based on pectin and chitosan were obtained by a cryotropic gelation method. Percentage of chitosan in the cryogels was estimated by elemental analysis. The obtained values were from 3.50 to 15.03 % for Apple pectin/Chitosan cryogels and from 9.44 to 17.64 % for Heracleum pectin/Chitosan cryogels. Internal structure and porosity of the cryogels were measured by scanning electron microscopy. According to the scanning electron microscopy, cryogels have a macroporous sheet-like structure. In the future, cryogels can be used in biotechnology and medicine as biocompatible, biodegradable materials.
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