Literatura za ispit iz kolegija "Suvremena društvena pitanja u SAD" i "Modern American Drama", postdiplomski studij amerikanistike, Dubrovnik, 1988

Literatura za postdiplomski studij amerikanistike u Dubrovniku, 1988., za ispite iz kolegija "Suvremena društvena pitanja u SAD" prof. Ognjena Čaldarovića, i kolegija "Modern American Drama" prof. Ivana V. Matkovića

Literatura za ispit iz kolegija "Suvremena društvena pitanja u SAD" i "Modern American Drama", postdiplomski studij amerikanistike, Dubrovnik, 1988

Literatura za postdiplomski studij amerikanistike u Dubrovniku, 1988., za ispite iz kolegija "Suvremena društvena pitanja u SAD" prof. Ognjena Čaldarovića, i kolegija "Modern American Drama" prof. Ivana V. Matkovića

Preparation and Crystal Data of N-(2-hydroxyethyl) taurine, HOCH2CH2NHCH2CH2SOJH

Taurine is a constituent of the bile acids. Since the knowledge of the crystal structure of taurine was important in understanding the biological role of the molecule, structural work on this compound was carried out by several authors1- 3. The last study3 has established that taurine possesses the zwitterion configuration with structural formula NHa+-CH2- CH2-S00-

Ispitivanje optičkih osobina grafena pomoću spektroskopske elipsometrije

The dissertation addresses the problem of retrieving the optical properties of graphene in the visible and UV ranges using ellipsometry. Additionally, it is demonstrated how changes in these properties could be related to various fabrication aspects including the transfer process and the interaction of graphene with various substrates. Besides their importance in advancing the fundamental understanding of optical properties of graphene, these results could be used for implementation of ellipsometry as a quality control in graphene-based technologies. As these technologies expand, it will be increasingly important to have tools which are able not only to detect the presence of a graphene layer but also to give information of subtle changes in the properties of these ultra thin films. Ellipsometry, due to its numerous advantages, is most definitely one of the techniques that will be employed as a quality control tool in the future mass production of graphene. In the dissertation optical properties of graphene were studied using spectroscopic ellipsometry and null spectroscopic imaging ellipsometry techniques. The studied samples were atomically thin layers of graphene synthesized by micromechanical exfoliation and chemical vapor deposition. These samples were supported by various substrates, such as silicon wafers with thin SiO2 films, transparent (sapphire) and metallic (gold) substrates. An importance of using corroborated measurements for building up an appropriate optical models has been shown as well. Optical parameters of graphene have been retrieved using a point-by-point inversion process, and afterwards parameterized by a dielectric function model. A proposed parametrization function of graphene’s complex refractive index is based on a Fano resonant profile. This model has only four fitting parameters, and their values can be easily related to the properties of the M-point exciton that causes the red shift of the prominent absorption peak in the UV. Various set of model paramv...Disertacija se bavi problemom merenja optičkih osobina grafena u vidljivom i ultraljubičastom delu spektra. Takodje, u disertaciji demonstrirano je kako se promene optičkih osobina mogu povezati sa pra´cenjem procesa sinteze, transfera, kao i interakcije grafena sa supstratom. Osim značaja za fundamentalno razumevanje optičkih osobina grafena, prikazani rezultati mogu se iskoristiti za implementaciju elipsometrije kao tehnike za kontrolu kvaliteta u novim tehnologijama zasnovanim na grafenu. Sa daljim razvojem ovih tehnologija, neophodno je imati adekvantne merne tehnike koje nisu osetljive samo na prisustvo mono-atomskog sloja, već su u stanju da pouzdano detektuju fine promene u osobinama ovih ultra tankih filmova. Zbog svojih brojnih prednosti, elipsometrija je zasigurno jedna od tehnika koja će biti korišćena za kontrolu kvaliteta, kao i procesa sinteze u budu´cim tehnologijama za masovnu proizvodnju grafena. U disertaciji optičke osobine grafena su merene pomo´cu tehnika nulirajuće i spektroskopske elipsometrije. Ispitivani su uzorci monoatomskih slojeva grafena, sintetisanih pomoću mikromehaničke eksfolijacije i depozicije iz gasne faze. Takodje, istaknut je značaj korišćenja korelacionih merenja za formiranje optičkih modela i interpretaciju elipsometarskih merenja grafena. Optičke konstante grafena su dobijene pomoću matematičke inverzije, a zatim parametrizovane pomoću modela dielektrične funkcije grafena. Predloženi model kompleksnog indeksa prelamanja grafena je zasnovan na Fano rezonantnom profilu. Ovaj model ima samo četiri parametra čije se vrednosti mogu jednostavno povezati sa osobinama eksitona u M-tački, koji izaziva crveni pomeraj apsorpcionog maksimuma u ultraljubičastom delu spektra. Različiti parametri modela dielektrične funkcije su prezentovani u disertaciji. Ovi parametri opisuju različite optičke osobine grafena koje su rezultat interakcije izmedju grafena i njegove okoline, eksternih v

Kinetics and mechanism of sphalerite leaching by sodium nitrate in sulphuric acid solution

Interest for application of hydrometallurgical processes in a processing of complex sulphide ores and concentrates has increased in recent years. Their application provides better metal recoveries and reduced emission of gaseous and toxic ageneses in the environment. The kinetics and mechanism of sphalerite leaching from complex sulphide concentrate with sulphuric acid and sodium nitrate solution at standard conditions was presented in this paper. The influences of temperature and time on the leaching degree of zinc were investigated and kinetic analysis of the process was accomplished. With temperature increasing from 60 to 90°C, the zinc leaching increased from 25.23% to 71.66% after 2 hours, i.e. from 59.40% to 99.83% after 4 hours. The selected kinetic model indicated that the diffusion through the product layer was the rate-controlling step during the sphalerite leaching. The activation energy was determined to be 55 kJ/mol in the temperature range 60-90°C. XRD, light microscopy and SEM/EDX analyses of the complex concentrate and leach residue confirmed formation of elemental sulphur and diffusion-controlled leaching mechanism

Crystal Structure of Citrobacter freundii Asp214Ala Tyrosine Phenollyase Reveals that Asp214 is Critical for Maintaining a Strain in the Internal Aldimine

Tyrosine phenol-lyase (TPL) is a pyridoxal-5′-phosphate (PLP) dependent enzyme which catalyzes β-elimination of L-tyrosine. In the holoenzyme the protonated pyridinium N1 atom of the PLP cofactor is hydrogen-bonded to the side chain of Asp214. Here we report the X-ray structure of C. freundii D214A TPL determined at 1.9 Å resolution. Comparison with the structure of the wild-type TPL shows that the D214A replacement induced significant conformational reorganization in the active site leading to its partial closure. Significantly, in D214A TPL the strain in the internal aldimine is completely released and the pyridine N1 atom of PLP is deprotonated. These observations explain the considerably reduced activity of the D214A TPL towards its substrates [T. V. Demidkina et al., Biochim. Biophys. Acta, Proteins Proteomics 1764 (2006) 1268–1276]. The reported structure reveals that Asp214 is critical for maintaining the strain in the internal aldimine. We argue that this strain is used by the enzyme to accelerate the transaldimination reaction, the first step in the enzymatic catalysis.(doi: 10.5562/cca1915

Preparation and Crystal Data of N-(2-hydroxyethyl) taurine, HOCH2CH2NHCH2CH2SOJH

Taurine is a constituent of the bile acids. Since the knowledge of the crystal structure of taurine was important in understanding the biological role of the molecule, structural work on this compound was carried out by several authors1- 3. The last study3 has established that taurine possesses the zwitterion configuration with structural formula NHa+-CH2- CH2-S00-

Istraživanja dekantacije »crvenog mulja« drniškog boksita

Upotrebom drniskog boksita kod alkalnog rascinjavanja po Bayer-u nastupaju znatne potreskoce. One sastoje u tome, sto se nakon reakcije u autoklavu i razrijedivanja reakcione smjese talozenja crvenog mulja odvija suvise polagano i neravnomjerno, zbog cega se znatno smanjuje produkcija