Structure and dielectric caracteristics of BaTi1-xSnxO3 ceramic powders

BaTi1-xSnxO3 (BTS) ceramic powders, with different tin content (x = 0-1) were prepared. The BTS powders were calcined at 1370 °C for 4 hours. The structure of these powders was characterized by XRPD method, tetragonal and cubic crystal structures were noticed. Powders were pressed in pellets and sintered at 1370 °C for 1 hour. The dielectric properties of BTS ceramics were measured and the results were reported.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Crystal structure analysis and first principle investigation of F doping in LiFePO4

This work presents the synthesis of F-doped LiFePO4/C composite by the specific modification of the recently suggested synthesis procedure based on an aqueous precipitation of precursor material in molten stearic acid, followed by a high temperature treatment. Besides the lattice parameters and the primitive cell volume reductions, compared to the undoped sample synthesized under the same conditions, the Rietveld refinement also shows that fluorine ions preferably occupy specific oxygen sites. Particularly, the best refinement is accomplished when fluorine ions occupy O(2) sites exclusively. By means of up-to-date electronic structure and total energy calculations this experimental finding is theoretically confirmed. Such fluorine doping also produces closing of the gap in the electronic structure and consequently better conductivity properties of the doped compound. In addition, the morphological and electrochemical performances of the synthesized powder are fully characterized

In situ XRPD and DSC study of order-disorder phase transition in nanosize Li-ferrite

An order-disorder phase transition of nanosize Li-ferrite (Li0.50Fe2.50O4) was studied by DSC measurements and in situ XRPD technique. The phase transition temperature is found to be 762 °C (DSC) and (745±5) °C (XRPD).Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

CaCu3Ti4-xRuxO12: Crystal structure, electrical and magnetic properties

The CaCu3 Ti 4 O12 belongs to the large ACu3B4 O12 family of materials. Crystallographic A site is most often occupied by alkaline-earth metals or lanthanides, while B site is occupied by transition metals. The type of cations that build up the structure strongly affects the properties of these. The CaCu 3 Ti 4 O12 has been extensively studied due to its high dielectric permittivity stable over a wide temperature and frequency range (up to 10 5 , for 100-600 K and 10 2 –105 Hz). Because of such characteristics, it has promising application in microelectronics. However, it has been shown that differences in the crystal structure and electrical properties of dielectric ceramics and metallic electrodes, may cause an energy barrier and occurrence of stress on the ceramic-electrode contact which reduces dielectric permittivity. Such stress can be prevented by using dielectric and electrode materials with as much as possible similar crystal structure, especially unit cell parameters. This investigation dealt with detailed structural (XRPD, HRTEM, SAED), dielectric and magnetic study of CaCu 3 Ti 4-xRuxO12 (CCTRO, x = 0, 1 and 4) materials. The results of structural refinement show that in cubic symmetry with space group 3Im , both titanium and ruthenium ions occupied crystallographic B site. Moreover, the variation in stoichiometry slightly affects the value of the unit cell parameters but changes electrical properties of studied material. Thus, substitution of even one atom of Ru in CaCu3 Ti 4-xRuxO12 unit cell is enough to change material properties from dielectric to conductor solving the problem of stress appearance on the contact layer of dielectric/electrode in capacitors.IX Serbian Ceramic Society Conference - Advanced Ceramics and Application : new frontiers in multifunctional material science and processing : program and the book of abstracts; September 20-21, 2021; Belgrad

Synthesis of f-doped LiFePO4 via precipitation method

Fluorine-doped, olivine-structured LiFePO4 suitable for cathode material in rechargeable lithium batteries was prepared by aqueous precipitation followed by high temperature treatment at 700°C under slightly reductive atmosphere (Ar+5%H2). The starting materials were equimolar quantities of (NH4)2HPO4, FeSO4·7H2O and LiF. LiF served as both lithium and fluorine source. Besides the lattice parameters and the primitive cell volume reductions, compared to the undoped sample synthesized under the same conditions using LiNO3 as lithium source, the Rietveld refinement also shows that fluorine ions preferably occupy specific oxygen sites. Particularly, the best refinement is accomplished when fluorine ions occupy O(2) sites exclusively. By means of up-to-date electronic structure and total energy calculations this experimental finding is theoretically confirmed. Such fluorine doping also produces closing of the gap in the electronic structure and consequently better conductivity properties of the doped compound. In addition, the morphological and electrochemical performances of the synthesized powders are fully characterized

Model trwałej eko-chemicznej edukacji pracowników przemysłu chemicznego

Employees of chemical industry play a significant role in environmental protection. In order to solve environmental problems it is necessary for them to improve knowledge on environmental impact of chemicals which they come in contact with. The aim of research is the analysis of the ecochemical knowledge in employees of the fertilizer industry in the Novi Sad region (Serbia), and structuring of chemical contents for further increase of their knowledge. Analytical and descriptive methods were used. The research instrument was a questionnairre, specially designed for the purpose of this research. Techniques of research were: field investigation, action investigation and combined techniques. It was shown that workers have certain, but insufficient knowledge of environmental effect of chemical pollutants. They should improve the existing and acquire new knowledge. A model of differentiated eco-chemical education was created for permanent adult professional education.Pracownicy przemysłu chemicznego odgrywają istotną rolę w ochronie środowiska. Aby rozwiązać problemy środowiskowe jest koniecznym, aby poprawić ich wiedzę na temat wpływu na środowisko substancji chemicznych, z którymi mają oni styczność. Celem badań jest analiza wiedzy eko-chemicznej pracowników przemysłu nawozów mineralnych w regionie Nowego Sadu (Serbia) i określenie zakresu wiedzy, który powinien zostać przez nich przyswojony w przyszłości. Użyto metod analitycznych i deskryptywnych. Zastosowanym narzędziem był oryginalny kwestionariusz. Rezultaty badań pokazują, że pracownicy posiadają wprawdzie pewną wiedzę o wpływie na środowisko związków chemicznych, jednak nie jest ona wystarczająca. W celu poprawy sytuacji zaproponowano model zróżnicowanej eko-chemicznej edukacji przygotowany dla osób dorosłych, pracujących zawodowo

Regional distribution of opiate alkaloids in experimental animals' brain tissue and blood

The aim of this study was to examine the regional distribution of opiate alkaloids from seized heroin in experimental animals' brain regions and blood. Results could be used in the examination of opiate alkaloids' distribution in human biological samples in order to contribute to the solution of the causes of death due to heroin intake. Experimental animals (Wistar rats) were treated with seized heroin, and were sacrificed at different time periods: 5, 15, 45 and 120 min after treatment. Opiate alkaloids' (codeine, morphine, acetylcodeine, 6- acetylmorphine and 3,6-diacetylmorphine) content was determined in the brain regions (cortex, brainstem, amygdala and basal ganglia) and blood of animals using gas chromatography-mass spectrometry (GC-MS) method. The highest content of opiate alkaloids in the blood was measured 15 min, and in the brain tissue 45 min after the treatment with heroin. The maximal concentration of opiates was determined in the basal ganglia. The obtained results offer the possibility of selecting this part of the brain tissue as a representative sample for identifying and assessing the content of opiates