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The chemical molten-salt process was used for the elaboration of a new polycrystalline perovskite compound of Ba0.97La0.02Ti0.95Nb0.04O3 (shortened in BLT0.95Nb0.04). Analysis of XRD patterns using Rietveld refinement reveals that the prepared sample crystallizes in single phase form, with a tetragonal structure, with a P4/mmm space group. Then, a simultaneous investigation of impedance and modulus was effectuated. Complex impedance plots confirm the existence of semicircular arcs which expressed by an electrical equivalent circuit to clarify the impedance consequences. Off-centered semicircular impedance plots makes obvious that the synthesis sample conforms to a non-Debye relaxation manner. Furthermore, it is typically controlled by thermally activated charge carriers. The reducing of resistance, with rising temperature (T), indicates a negative temperature coefficient of resistance, which highlighting that the relaxation process is dominated by the inter-grains.

The effect of phenol solubilization on the behavior of (ethylene oxide)78-propylene oxide)30-(propylene oxide)78 (EO78-PO30-EO78) tri-block copolymer, Pluronic F68 (F68), in aqueous suspensions was...

Depuis 2015, un vaste projet de coopération francophone, sous couvert de l’Agence universitaire de la Francophonie (AUF), mobilise des acteurs/trices scientifiques de la recherche et de l’enseignement de pays européens et du sud-est asiatique. Des universités européennes francophones sont entrées conjointement avec des universités vietnamiennes, cambodgiennes et laotiennes dans une dynamique de collaboration active dans la perspective d’un transfert de technologies, mais aussi d’une mutualisation d’expériences dans la gouvernance universitaire par le numérique. Études, expertises, formations, publications et projets constituent des mécanismes d’amélioration de la qualité, de la pertinence et de l’efficience tant de la recherche que de l’enseignement pour les différents partenaires. Aujourd’hui, des équipes ad-hoc, des comités d’experts, des consortiums et des délégations internationales participent de la redéfinition d’une culture scientifique de la recherche et de l’innovation pédagogique par le numérique, faisant de la disparité des contextes et de l’asymétrie entre les acteurs du Nord et du Sud un vecteur d’innovation et d’enrichissement d’expériences.

Conductivity measurements of our polycrystalline perovskite ceramic systems with a composition of Ba0.97La0.02Ti1−xNb4x/5O3 (x = 5, 7 and 10, in mol%) were performed, in order to investigate frequency and temperature dependence. Our ferroelectric ceramics were fabricated by the molten-salt method (chemical reaction followed by an evaporation and filtration reaction); X-ray diffraction patterns indicated that a single phase was formed for pure BaLT1−xNb4x/5 ceramics. The electrical behavior of the ceramics was studied by impedance spectroscopy in the 500–610 K temperature range. The conductivity was investigated which can be described by the Jonscher law. Both AC and DC electrical conductivities are completely studied as a function of frequency and temperature. The conductivity exhibits a notable increase with increasing Nb-rates. The low-frequency conductivity results from long-range ordering (close to frequency-independent) and the high-frequency conductivity is attributable to the localized orientation hopping process. Impedance analysis was performed revealing conductivity data which fitted the modified power, σAC(ω) = Aωn. The frequency dependence of the conductivity plot has been found to obey the universal Jonscher power law. Both AC and DC electrical conductivities are thoroughly studied as a function of frequency as well as temperature. The AC conductivity reveals that correlated barrier hopping (CBH) and non-overlapping small polaron tunneling (NSPT) models are suitable theoretical models to elucidate the conduction mechanisms existing in our compounds. Significantly, by increasing the temperature, the DC conductivity was increased, which verifies the semiconducting nature of the materials.

SrO-Bi2O3- B2O3 glass systems with different content of neodymium oxide Nd2O3 were prepared by rapid-quenching technique. On Record FTIR deconvoluted spectra were in the range of 400–2000 cm-1. Some parameters such as; density and molar volume were acquired. Ultrasonic wave velocities (longitudinal and shear) and elastic moduli were acquired. The results were interpreted as due to the role of Nd2O3. Formation of BO4 causes an increase in the rigidity of glass, and consequently resulted an increase in the glass density. Increment of molar volume revealed that addition of Nd2O3 results in an extension of glass network. The presence of [BiO6] octahedral units builds up the bismuthate structure of investigated glasses. The Nd3+ ions caused the proportion of average bonds elongations to diminish from 48.18 % to reach the value of 45.59 % at 5.7 mol. % of Nd2O3.

During the early development stages of the 5G specifications by 3GPP, it was quickly identified that it is not possible to address all the use cases of the 5G System within the normal Release timeframe. Therefore, it was decided to split the work in two phases. The 5G Phase 1 work focused on the foundation of the new system while 5G Phase 2 focused more on the needed enhancements to address the use cases. The work on the security in 5G Phase 1 was ample enough to deliver all the needed mechanisms not only to secure the communication between the different entities but also to protect the privacy of the user. Therefore, it is expected that the work on 5G Phase 2 will unlikely have impact on the security mechanisms. Nevertheless, some of the new features in 5G Phase 2 give rise to subtle security challenges which may require enhancements to the existing mechanisms. In this article, we consider some of the 5G Phase 2 features and shed light on such security aspects.