Search results for "MATERIALS"
showing 10 items of 29608 documents
The effect of noise, a constant background, and bit depth on the phase retrieval of pure phase objects
2021
Acknowledgements – The authors are supported by the postdoctoral project (1.1.1.2/16/I/001; 1.1.1.2/ VIAA/1/16/199, State Education Development Agency, Republic of Latvia).
On the high-pressure phase stability and elastic properties ofβ-titanium alloys
2017
We have studied the compressibility and stability of different β-titanium alloys at high pressure, including binary Ti–Mo, Ti–24Nb–4Zr–8Sn (Ti2448) and Ti–36Nb–2Ta–0.3O (gum metal). We observed stability of the β phase in these alloys to 40 GPa, well into the ω phase region in the P–T diagram of pure titanium. Gum metal was pressurised above 70 GPa and forms a phase with a crystal structure similar to the η phase of pure Ti. The bulk moduli determined for the different alloys range from 97 ± 3 GPa (Ti2448) to 124 ± 6 GPa (Ti–16.8Mo–0.13O).
Surfactant-Mediated Morphology and Photocatalytic Activity of α‑Ag2WO4 Material
2018
In the present work, the morphology (hexagonal rod-like vs cuboid-like) of an α-Ag2WO4 solid-state material is manipulated by a simple controlled-precipitation method, with and without the presence of the anionic surfactant sodium dodecyl sulfate (SDS), respectively, over short reaction times. Characterization techniques, such as X-ray diffraction analysis, Rietveld refinement analysis, Fourier-transform (FT) infrared spectroscopy, FT Raman spectroscopy, UV–vis spectroscopy, transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction, energy-dispersive X-ray spectroscopy, field emission-scanning electron microscopy (FE-SEM), and photoluminescence emission…
Unravelling the Photocatalytic Behavior of All-Inorganic Mixed Halide Perovskites: The Role of Surface Chemical States
2019
Within the most mesmerizing materials in the world of optoelectronics, mixed halide perovskites (MHPs) have been distinguished because of the tunability of their optoelectronic properties, balancing both the light-harvesting efficiency and the charge extraction into highly efficient solar devices. This feature has drawn the attention of analogous hot topics as photocatalysis for carrying out more efficiently the degradation of organic compounds. However, the photo-oxidation ability of perovskite depends not only on its excellent light-harvesting properties but also on the surface chemical environment provided during its synthesis. Accordingly, we studied the role of surface chemical states …
Degradation of Lincomycin in aqueous medium: coupling of solar photocatalysis and membrane separation
2005
Abstract The photocatalytic oxidation of a common antibiotic, the lincomycin was carried out in aqueous suspensions of polycrystalline TiO 2 Degussa P25 irradiated by sunlight. In order to improve the performance of the lincomycin degradation a hybrid system consisting of a solar photoreactor with the photocatalyst in suspension coupled with a membrane module, used to confine both photocatalyst and pollutants in the reaction environment, was tested. A preliminary study was carried out in order to determine some kinetics parameters of the drug photodegradation. The influence of initial substrate concentration on the lincomycin photooxidation rate was investigated. The photooxidation rate fol…
Hard x-ray photoelectron spectroscopy: a snapshot of the state-of-the-art in 2020
2021
Journal of physics / Condensed matter 33(23), 233001 (1-44) (2021). doi:10.1088/1361-648X/abeacd
Photocatalytic Generation of H2 by Photoreforming of Organics in Aqueous Suspension of Nb2o5/C3n4 Composites
2023
Bare and composite materials based on C3N4 and Nb2O5 have been used as photocatalysts for the photoreforming of aqueous solutions of oxygenated compounds. Both Nb2O5 and Nb2O5/C3N4 composites have been prepared by hydrothermal synthesis and all of them were physical-chemically characterized. In this work two different carbon nitride species i.e. graphitic (g-C3N4) or thermo-etched (TE-C3N4) were used both alone or coupled with Nb2O5. The photo-reforming activity has been measured under UV irradiation by using the semiconductors in the presence of Pt as co-catalysts and, in the case of the best material, it was, for the first time, measured and compared also under natural solar irradiation. …
Thin Film CIGS Solar Cells, Photovoltaic Modules, and the Problems of Modeling
2013
Starting from the results regarding a nonvacuum technique to fabricate CIGS thin films for solar cells by means of single-step electrodeposition, we focus on the methodological problems of modeling at cell structure and photovoltaic module levels. As a matter of fact, electrodeposition is known as a practical alternative to costly vacuum-based technologies for semiconductor processing in the photovoltaic device sector, but it can lead to quite different structural and electrical properties. For this reason, a greater effort is required to ensure that the perspectives of the electrical engineer and the material scientist are given an opportunity for a closer comparison and a common language.…
Numerical procedures and their practical application in PV module analyses. Part III: parameters of atmospheric transparency – determining and correl…
2023
The presented article examines aspects of a PV module testing using natural sunlight in outdoor conditions. The article discusses the physical sense of indexes: atmosphere purity, diffused component content, beam clear sky index. Procedures for their determination are given in relation to both instantaneous and daily values. Their close connection with the values of solar irradiance spectral distribution such as Average Photon Energyand Useful Fractionis demonstrated, as well as their usefulness in moduletesting in outdoor conditions. Their influence on the conversion of modules made from various absorbers and various technologies is demonstrated
Assessment of Physical and Chemical Stability of Different Magnesium Compounds in Tablets
2020
Modern lifestyle, excessive chemicalization of agricultural products, excessive processing and refining of food, cause a decrease in daily intake of magnesium, cation with an extremely important role in prevention and treatment of many diseases. As a result, there arises the need for extra magnesium intake in the form of dietary supplements. In this study were evaluated the physical and chemical stability of magnesium-containing tablets, depending on the active compound and the excipients used. Magnesium tablets in the form of orotate, lactate, citrate, oxide and hydroxide were taken into study and physical and chemical stability were observed over the validity period, at 6 and at 12 month…