Papers by Keyword: Eu

Abstract: Cloud computing systems usage in enterprises has become very popular in recent years. On the world market there is an increasing number of cloud computing services providers with more or less complex solutions in their offer. Thanks to cloud computing services SMEs have the chance to compete with big corporations. The article presents the usage of cloud computing in the European enterprises in comparison with enterprises from the United States, the use of cloud computing solutions in enterprises of the EU countries in 2014 and prognosis on the use of cloud technologies in Eastern European countries between 2014 and 2017. The aim of the article is to present the current state of cloud systems adoption in European enterprises and to conduct the comparative analysis of the data structure based on the rough sets theory.

Abstract: Glass-ceramic was precipitated on the oxyfluoride glass surface by thermal annealing with a CO₂ laser and a heat gun. Micro x-ray diffraction showed the formation of CaF₂ ain the exposed region to the laser. Dopant distribution in glass ceramics was probed by confocal fluorescence microscope by observing much strong emission from Eu ions than the glassy area under 405 nm excitation. Much enhanced visible emissions under 365 nm excitation also showed well incorporation of Eu³⁺ ions into a crystalline environment.

Abstract: We report on photoluminescence (PL) properties of europium (Eu) and ytterbium (Yb) co-doped silicon oxide films with different Si excess. After annealing the films in N₂, strong PL were observed from Eu and Yb³⁺ ions and their intensities are correlated. The PL intensity of Eu is mainly from 3+ for no and relatively low temperature anneals (<900 ^°C) while the Eu²⁺ emission is dominating for annealing at 1000 ^°C or above in the co-doped Si-rich oxide films. Transmission electron microscopy shows amorphous (Eu, Yb, Si, O)-containing precipitates in the Si-rich oxide during 1000-1200 ^°C annealing and these precipitates are considered to be responsible for the Eu²⁺-related luminescence.