Teatr w Serbii w latach 1990-2010

Rozdział autorstwa Nebojšy Romčevicia, serbskiego teatrologa, dramatopisarza i scenarzysty, mówiący o współczesnym teatrze i dramacie serbskim w latach 1990-2010. Jeden z dwóch wstępów poprzedzających polski wybór i przekłady dramatu serbskiego

Ellipsometric measurements of plastically deformed copper

Chemically pure copper (99.99) prepared in the sample of square cross-section (10 x 10 mm2) and length about 50 mm was extremely plastically deformed with the repeated application of equal channel angular pressing. Equal channel angular pressing was applied as an effective technique for producing bulk nanoscaled structures. It is well known that severe plastic deformation of metallic materials often leads to microstructure with ultrafine grains and cross-sections which remain about equal before and after deformation. Optical properties of the sample were studied using spectroscopic ellipsometry in UV-VIS range. The parameters of the sample like copper oxide and surface roughness overlayer were calculated using two-film model together with the Bruggeman effective medium approximation

Characterization of Barium Titanate Ceramic Powders by Raman Spectroscopy

Barium titanate, BaTiO3 ceramic powders were prepared by mechanochemical synthesis and by the Pechini method. A powder mixture of BaO and TiO2 was treated in a planetary ball mill in an air atmosphere for Lip to 1 h, using zirconium oxide vial and zirconium oxide balls as the milling medium. After 60 min BaTiO3 phase was formed. In both ways BaTiO3 ceramics were sintered after 2 h on 1300 degrees C without pre-calcinations step. The heating rate was 10 degrees C min(-1). The formation of phase and crystal structure of BaTiO3 was approved by X-ray diffraction analysis and the Raman spectroscopy. The morphology and microstructure of obtained powders were examined by scanning electron microscopy method. Sharp phase transition from ferroelectric to paraelectric state was observed. The hysteresis loop is very well performed with regular sharp characteristic of ferroelectric materials

Kарактеризација наночестица кобалт ферита добијених различитим методама синтезе и поређење са Рамановим спектрима других ферита и неких кубичних оксидних спинела

ingle phase cobalt ferrite (CoFe2O4) with nanoparticles of similar sizes (15.7-19 nm) was obtained by different synthesis methods: coprecipitation, ultrasonically assisted coprecipitation, coprecipitation followed by mechanochemical treatment, microemulsion and microwave assisted hydrothermal synthesis. The obtained CoFe2O4 samples have been studied using a variety of characterization techniques: X-ray diffraction (XRD), Raman spectroscopy, far infrared (FIR) reflectivity and attenuated total reflectance (ATR) in combination with Fourier-transform infrared (FTIR) spectroscopy in mid IR spectra. Different methods of synthesis produced nanoparticles with different lattice constants, internal stresses and different cation inversion values. This is confirmed in the subtle changes in the Raman and IR spectra of different CoFe2O4 nano-powders. The Raman spectra of CoFe2O4 were compared with the spectra of other ferrites and some cubic oxide spinels in an attempt to evaluate the contribution of tetrahedral and octahedral oscillations in certain Raman modes.Монофазни кобалт ферит са наночестицама сличних величина (15,7-19 нанометара) добијен је различитим методама синтезе: копреципитацијом, ултразвучно потпомогнутом копреципитацијом, копреципитацијом праћеном механохемијском синтезом, микроемулзијом и микроталасном хидротермалном синтезом. Добијени узорци кобалт ферита су проучавани коришћењем различитих техника карактеризације: дифракцијом рендгенских зрака на праху, Раман спектроскопијом, рефлексијом у далекој инфра-црвеној области (ИЦ) и методом апсорпције при вишеструкој тоталној рефлексији у комбинацији са инфра-црвеном спектроскопијом (АТР-ИЦ) у средњој инфра црвеној области. Различитим методама синтезе добијене су наночестице са различитим константама решетке, унутрашњим напрезањима и различитим вредностима инверзије катјона. Ово је потврђено у суптилним променама у Раман и ИЦ спектрима различитих нано-прахова кобалт ферита. Раман спектри кобалт ферита упоређени су са спектрима других ферита и неких кубних оксидних спинела у покушају да се процени утицај удела тетраедарских и октаедарских осцилација у одређеним Раман модовима

Optical properties of plastically deformed copper

Pure copper (99.99), prepared in the sample of square cross-section (10 x 10 mm2) and length about 50 mm, was extremely plastically deformed with the repeated application of Equal Channel Angular Pressing (ECAP). ECAP was applied as an effective technique for producing bulk nano-scaled structures. Optical properties of the sample were investigated using Raman spectroscopy. Two types of lines: narrow (with width of 7 cm¡1) and wide ( 40 cm¡1) are registered. Existence of two types of lines indicates that in the specimen exists nano-sized crystal structures of both Cu and CuO related with three dimensional amorphous boundary spaces, which indicates that plastic deformation of the sample did not lead to total amorphisation of the specimen

Study of Barium Bismuth Titanate Prepared by Mechanochemical Synthesis

Barium-bismuth titanate, BaBi4Ti4O15 (BBT), a member of Aurivillius bismuth-based layer-structure perovskites, was prepared from stoichiometric amounts of barium titanate and bismuth titanate obtained via mechanochemical synthesis. Mechanochemical synthesis was performed in air atmosphere in a planetary ball mill. The reaction mechanism of BaBi4Ti4O15 and the preparation and characteristics of BBT ceramic powders were studied using XRD, Raman spectroscopy, particle analysis and SEM. The Bi-layered perovskite structure Of BaBi4Ti4O15 ceramic forms at 1100 degrees C for 4 h without a pre-calcination step. The microstructure of BaBi4Ti4O15 exhibits plate-like grains typical for the Bi-layered structured material and spherical and polygonal grains. The Ba2+ addition leads to changes in the microstructure development, particularly in the change of the average grain size

Local and electronic structure around manganese in Cd0.98Mn0.02Te0.97Se0.03 studied by XAFS

X-ray Absorption Fine Structure (XAFS) technique was employed to study local electronic and structural features of Mn ions incorporated in Cd0.98Mn0.02Te0.97Se0.03. XAFS measurements performed at Mn K edge revealed that manganese Mn(II) ions are well incorporated into the host CdTe lattice (cubic zinc-blende structure type) and their immediate surrounding is found to be composed exclusively of Te atoms. The observed preference of Mn ions distribution around Te opposes earlier observations on the similar systems, where preferential Mn-Se over Mn-Te paring was found.15th International Conference on X-Ray Absorption Fine Structure (XAFS), Jul 22-28, 2012, Beijing, Peoples R Chin

Photoluminescence Spectroscopy of CdTe/ZnTe Self-Assembled Quantum Dots

We present photoluminescence (PL) measurements of two different, 3 monolayers and 12 monolayers (ml), CdTe self-assembled quantum dot (SAQD) samples. The spectra were recorded in the temperature range 20 K–300 K, with photoexcitation over the ZnTe barrier layer. PL spectra displayed two main emission bands. High-energy PL emission (E1) is ZnTe LO like phonon- (ωLO = 204.2 cm−1 (3 ml), ωLO = 207.3 cm−1 (12 ml)) assisted deexcitation. Dominant low-energy band (E2) presents the direct deexcitation to ground state of the CdTe quantum dots

Vibrational and magnetic properties of nano-sized CoFe2O4 obtained by various synthesis techniques: a comparative study

Nanocrystalline CoFe2O4 has been synthesized by various synthesis methods. The obtained monodomain nanoparticles are similar in sizes (15.8-19 nm), but with different internal stresses, size distributions and cation inversion coefficients (0.51 - 0.90) due to different synthesis routes. The structure and cation distribution are investigated by XRD diffraction analysis, Raman and FIR spectroscopy. Measurement of magnetization, i.e. coercivity, enable the calculation of the anisotropy coefficient K1 = (3.6-5.12)·105 J cm-3, which is very high in cobalt ferrite. The anisotropy coefficient directly depends on the nanoparticle size. It has been shown that magnetization linearly depends on the cation inversion, except in the sample with the largest nanoparticles (19 nm), where the more regular crystal structure prevails and higher values of magnetization were obtained. The average magnetic moments at 300 K are: μFe = 3.6μB and μCo = 2.5μB. It is obvious that with small adjustments in the synthesis, desirable nanoparticle properties can be obtained

RAMAN SPECROSCOPY STUDY OF ANODIC FILM ON Ag43Cu37Zn20 ALLOY

The aim of the present work is characterization of electrochemically treated Ag43-Cu37-Zn20 alloy in near neutral chloride solutions by the X-ray diffraction and Raman spectroscopy. At potential of +0.25 V, a complex multilayer film is formed. XRD shows that it consists of CuCl and zinc hydroxichlorides with small amount of Cu2O, probably formed in the film pores. It can be concluded that the Raman spectroscopy is observed almost all the modes that are registered with the XRD analysis