Šioje daktaro disertacijoje pirmoje dalyje nustatyta šiuolaikinės, o antroje dalyje – archeologinės keramikos gaminių elementinė ir fazinė sudėtis, bei ištirta morfologija. Šiuolaikinės ir archeologinės keramikos pavyzdžių elementinė sudėtis nustatyta Rentgeno spindulių dispersinės analizės (EDX), liepsnos atominės absorbcinės spektrometrijos (LAAS), titrimetrinės ir spektrofotometrinės analizės metodais. Parodyta, kad visų keraminių pavyzdžių kokybinė bei kiekybinė sudėtis yra skirtinga Nustatyta, kad visuose keramikos mėginiuose pagrindiniai elementai yra silicis ir aliuminis. SiO2 sudaro 46 – 60% keramikos sudėties, Al2O3 – apie 17 – 33%. Fe, Na, Mg, K, Ca ir Ti mėginiuose rasta kelis kartus mažiau. EDX analizė gali būti sėkmingai naudojama nustatant pagrindinius elementus, kurių kiekiai viršija 0,5 % bendros elementinės sudėties. Norint nustatyti tikslią keramikos sudėtį ir pėdsakinius elementus reikia naudoti LAAS analizės metodą. Aliuminio kiekį keramikoje patikimai galima nustatyti titrimetriniu, o silicio ir titano kiekį – spektrofotometriniais metodais. Ištyrus šiuolaikę ir archeologinę keramiką Rentgeno spindulių difrakcine analize (XRD), nustatyta, kad visų keramikų pagrindinė fazė yra vienoda – silicio dioksidas SiO2, tačiau jų bendra fazinė sudėtis skiriasi. Skirtinguose kermikos pavyzdžiuose buvo aptikos šios fazės: kvarcas, dolomitas, kaolinas, albitas, mikroklinas, muskovitas, mulitas, hematitas, rutilas, diopsidas, korundas, titanitas, natrio anortitas... [toliau žr. visą tekstą] / The elemental composition of the samples of modern and archaeological ceramics was determined using the energy dispersive X-ray analysis, flame atomic absorption spectrometry, titrimetric and spectrophotometric analysis methods. It has been shown that the qualitative and quantitative composition of all the samples is different. It has been established that silicon and aluminium are the main elements in all the samples. SiO2 accounts for 46–60 % of the composition of the ceramics, Al2O3 – for some 17–33%. The amounts of Fe, Na, Mg, K, Ca and Ti discovered in the samples are several times lesser. EDX analysis can successfully be used in determining the main elements whose amounts exceed 0.5% of the overall elemental composition. In order to determine the exact composition of ceramics one has to employ the FAAS analysis method. To determine in a credible manner the amount of aluminium in ceramics, one can use the titrimetric method, and the amount of silicon and titanium – spectrophotometric methods. Upon examination of the modern and archaeological ceramics by diffraction analysis it has been established that the main phase of all the samples is the same – quartz SiO2, however their phase composition varies. In different samples the following phases have been discovered: calcite, dolomite, kaolinite, albite, microcline, muscovite, mullite, hematite, rutile, diopside, corundum, titanite, and sodium anorthite. Being aware of the phase composition, it has been established that the... [to full text]

<p>U ovom radu prikazani su rezultati ispitivanja termičkih, mehaničkih, električnih i optičkih karakteristika kvazibinarnih halkogenida iz sistema Bi-As2S3. Na osnovu termičkih merenja analizirana je kinetika kristalizacionih i predkristalizacionih procesa i utvrđen je mehanizam dekompozicije za različite sastave dobijenih stakala. Primenom impedansne spektroskopije kvantitativno su ocenjeni doprinosi relaksacionih procesa na pojedinim temperaturama u ukupnoj polaraziciji za stakla sa 5 i 7 at.% Bi. Na osnovu merenja Raman spektroskopije identifikovane su nastale strukturne jedinice i konstatovana pojava nanofazne separacije u staklima sa 1.5 i 3 at.% Bi. Mehanička merenja ispitivanih halkogenida različitog sastava ukazala su na povećanje Vickers-ove tvrdoće sa povećanjem udela primesnih atoma. Na osnovu procenjene vrednosti modula elastičnosti ustanovljeno je da uzorak sa 5 at.% Bi odlikuje najgu&scaron;će atomsko pakovanje. Merenja električnih karakteristika u jednosmernom režimu (DC) pokazala su da je udeo lokalizovanih stanja u ukupnom mehanizmu provođenja značajan samo za manje koncentracije primesnih atoma, a da za veće koncentracije dominantan faktor postaju preskoci između delokalizovanih stanja. Skok u provodljivosti za nekoliko redova veličine kod sastava sa složenijom strukturom protumačen je kao posledica fazne separacije. Rezultati&nbsp; ACmerenja dobijeni za sastav sa 5 at.% Bi ukazali su da je u mernom frekventnom intervalu i dalje dominantan mehanizam termičke aktivacije nosilaca naelektrisanja. Kod sastava sa maksimalnim sadržajem Bi uočena je promena provodljivosti u funkciji frekvencije na svim temperaturama, a dobijeni rezultati su u skladu sa postavkama modela korelisanih preskoka barijere (CHB model).</p> / <p>This paper presents the results of investigation ofthermal, mechanical, electrical and optical propertiesof quasibinar chalcogenides from the system Bi-As2S3.&nbsp;Kinetics analysis of softening and crystallizationprocesses was done on the basis of thermalmeasurements, as well the analysis of decompositionmechanism for different compositions of obtainedglasses. The application of impedance spectroscopy enabled quantitative description of relaxation process contributions at selected temperatures in the overallpolarization for the samples with 5 and 7 at.% Bi.&nbsp;Based on measurements of Raman spectroscopy identification of structural units in the investigated chalcogenides was made, as well as the appearance of&nbsp;nano-scale phase separation in the glasses with 1.5 and 3 at.% Bi. Mechanical measurements pointed to the increase of the Vickers hardness with increase of&nbsp;doping atoms content. &nbsp;Based on the estimated value of the modulus of elasticity it was found that the sample &nbsp;with 5 at.% Bi is characterized by the densest atomic&nbsp;arrangement. Measurements of the electrical properties in dc regime (DC) pointed out that the share of localized states in the whole mechanism of conduction&nbsp;is significant only for the smaller concentrations of doping atoms. For the samples with higher concentrations dominant &nbsp;factor in conductivity are transitions between delocalized states. The jump in conductivity by few orders of magnitude, noticed for&nbsp;the compound with heterogeneous structure was interpreted as a consequence of micro-scale phase&nbsp; separation. Results of&nbsp; ACmeasurements for the&nbsp; composition with 5 at.% Bi showed that the mechanism of thermal activation of charge carriers is&nbsp;still dominant in the measured frequency range. For&nbsp;&nbsp; the composition with the maximum content of Bi changes in conductivity versus frequency were observed at all temperatures, and the results were interpreted in accordance with the model of correlated hopping over the barrier (CHB).</p>