Search results for "Note"
showing 10 items of 10709 documents
Study of phase transition in Bi3TiNbO9-BaBi2Nb2O9 ceramics
2016
Abstract The subject of the paper is lead free bismuth layer structure oxides (1-x)Bi3TiNbO9-xBaBi2Nb2O9 (x=0; 1; 2; 3 mol). The influence of Bi3TiNbO9/BaBi2Nb2O9 ratio on dielectric and structural properties was studied in a wide range of temperatures. Change in the ratio causes a decrease in the maximum value of dielectric permittivity and shifts the temperature of ε’max to low values, leading to linear decreasing of average grain size and linear increasing of ceramics density. These results indicate an augment of the packing degree and the participation of pores are significantly decreased with the increase of BaBi2Nb2O9 compound intake. Moreover, for 0.7Bi3TiNbO9-0.3BaBi2Nb2O9 ceramics …
Wo3 and ionic liquids: A synergic pair for pollutant gas sensing and desulfurization
2020
This review deals with the notable results obtained by the synergy between ionic liquids (ILs) and WO3 in the field of pollutant gas sensing and sulfur removal pretreatment of fuels. Starting from the known characteristics of tungsten trioxide as catalytic material, many authors have proposed the use of ionic liquids in order to both direct WO3 production towards controllable nanostructures (nanorods, nanospheres, etc.) and to modify the metal oxide structure (incorporating ILs) in order to increase the gas adsorption ability and, thus, the catalytic efficiency. Moreover, ionic liquids are able to highly disperse WO3 in composites, thus enhancing the contact surface and the catalytic abilit…
Structural characterization and optical constants of p-toluene sulfonic acid doped polyaniline and its composites of chitosan and reduced graphene-ox…
2020
Para-Toluene sulfonic acid doped polyaniline (PANI), PANI/chitosan composites, PANI/reduced graphene-oxide composites and a ternary composite comprising of PANI, chitosan and reduced graphene-oxide have synthesised via oxidative polymerisation of aniline by Ammonium peroxydisulfate (APS). FTIR, XRD, FESEM and UV-VIS techniques were performed for the confirmation of the successful synthesis. The fundamental optical parameters such as, complex refractive index, complex dielectric constants and optical conductivity of the PANI and the composites were investigated in the UV-VIS-NIR range. The results show a clear dependence on the constituent component such as sulphur as well as the absorbance …
Electrochemical Oxidation of Hf-Nb Alloys as a Valuable Route to Prepare Mixed Oxides of Tailored Dielectric Properties
2018
Metal oxides with high dielectric constant are extensively studied in the frame of substituting SiO2 as gate dielectric in nanoelectronic devices. Here, high-k mixed HfO2/Nb2O5 oxides are prepared by a facile electrochemical route starting from sputtering-deposited Hf–Nb alloys with several compositions. Transmission electron microscopy, grazing incidence X-ray diffraction, and glow discharge optical emission spectroscopy are employed to study the oxide structures, disclosing a crystalline–amorphous transition of the electrochemically prepared oxides by increasing the Nb content. Photo-electrochemical measurements allow the observation of optical transitions ascribed to localized states ins…
Hidroloģisko un hidroķīmisko rādītāju izvērtējums Tērvetes upes baseinā
2018
Bakalaura darba tēma: “ Hidroloģisko un hidroķīmisko rādītāju izvērtējums Tērvetes upes baseinā”. Bakalaura darba mērķis ir izvērtēt Tērvetes upes hidroloģiskā režīma ilgtermiņa un sezonālās izmaiņas un hidroķīmiskā režīma sezonālās izmaiņas. Pētījumā ir izmantotas hidroloģisko un hidroķīmisko novērojumu datu rindas no Bramberģes un Tērvetes (augšup Tērvetes ciema) novērojumu stacijām. Hidroloģisko novērojumu dati iegūti laika periodam no 1985.-2017.gadam (ledus režīma dati no 1985.-2009.g.) un hidroķīmiskie dati no 2005.-2017.gadam. Klimats Tērvetes upes baseinā raksturots pēc Dobeles meteoroloģiskās novērojumu stacijas datu rindas laika posmam 1961.-2017.gadam. Monitoringa novērojumu datu…
The Influence of Chemical Composition of Commercial Lemon Essential Oils on the Growth of Candida Strains
2013
Candida yeasts are saprophytes naturally present in the environment and forming colonies on human mucous membranes and skin. They are opportunistic fungi that cause severe and even fatal infections in immunocompromised individuals. Several essential oils, including eucalyptus, pine, cinnamon and lemon, have been shown to be effective against Candida strains. This study addresses the chemical composition of some commercial lemon essential oils and their antifungal potential against selected Candida yeast strains. Antifungal potential and minimum inhibitory concentrations were determined for six commercial lemon essential oils against five Candida yeast strains (Candida albicans 31, Candida t…
"15 Latvijas pilsētu notekūdeņu metagenoma taksonomiskais un funkcionālais raksturojums"
2021
Neattīrīti notekūdeņi ir ķīmiski un bioloģiski kompleksa vide, taču tā mikrobioloģiskais sastāvs līdz šim ir maz pētīts. Izmantojot šobrīd pieejamās sekvencēšanas un bioinformātikas tehnoloģijas, ir iespējams raksturot notekūdeņu mikroorganismu kopienas sastāvu dažādos līmeņos. Bakalaura darba mērķis bija taksonomiski un funkcionāli raksturot 15 Latvijas pilsētu notekūdeņu metagenomus. DNS tika izdalīta no neattīrītu, 24 h periodā ievāktu koncentrētu notekūdeņu paraugiem, un tai, izmantojot lielapjoma paralēlo sekvencēšanu, tika veikta visa metagenoma analīze. Datu analīzes rezultātā tika noskaidrots, ka pilsētu notekūdeņu metagenomos ir saskatāmas līdzības sugu, ģints, tipa un gēnu līmeņos…
Flash infrared annealing as a cost-effective and low environmental impact processing method for planar perovskite solar cells
2019
Abstract For successful commercialization of perovskite solar cells, straightforward solutions in terms of environmental impact and economic feasibility are still required. Flash Infrared Annealing (FIRA) is a rapid method to fabricate perovskite solar cells with efficiencies >18% on simple, planar architecture, which allows a film synthesis in only 1.2 s, faster than the previous report based in a meso architecture and all of them without the usage of antisolvent. In this work, through a comparative study with the common lab-scale method, the so-called antisolvent (AS), the main photovoltaic parameters and working mechanisms obtained from impedance spectroscopy (IS) measurements show simil…
Fluorescent Biosensors Based on Silicon Nanowires
2021
Nanostructures are arising as novel biosensing platforms promising to surpass current performance in terms of sensitivity, selectivity, and affordability of standard approaches. However, for several nanosensors, the material and synthesis used make the industrial transfer of such technologies complex. Silicon nanowires (NWs) are compatible with Si-based flat architecture fabrication and arise as a hopeful solution to couple their interesting physical properties and surface-to-volume ratio to an easy commercial transfer. Among all the transduction methods, fluorescent probes and sensors emerge as some of the most used approaches thanks to their easy data interpretation, measure affordability…
State of the art and prospects for halide perovskite nanocrystals
2021
Financiado para publicación en acceso aberto: Universidade de Vigo/CISUG Metal-halide perovskites have rapidly emerged as one of the most promising materials of the 21st century, with many exciting properties and great potential for a broad range of applications, from photovoltaics to optoelectronics and photocatalysis. The ease with which metal-halide perovskites can be synthesized in the form of brightly luminescent colloidal nanocrystals, as well as their tunable and intriguing optical and electronic properties, has attracted researchers from different disciplines of science and technology. In the last few years, there has been a significant progress in the shape-controlled synthesis of …