Recent Developments in Advanced Materials and Processes

Volume 518

doi: 10.4028/

Paper Title Page

Authors: N. Pantelić, A. Piruska, Carl J. Seliskar
Abstract: A chemically selective film, usually of optical quality, is a key component of optical and electrochemical sensors. We have examined the dynamics of various thin selective films by spectroscopic ellipsometry and attenuated total reflectance (ATR) spectroscopy. Spectroscopic ellipsometry provided a non-invasive method for measurement of optical constants (n(λ), refractive index; k(λ), extinction coefficient) and thicknesses of thin selective films which were conditioned in time by solvent and penetrant mass transport. The methods we have developed allowed us to characterize film dynamic response, stability, and chemically specific mass transport even to the point of quantitatively modeling both transport and structural changes. The ATR spectra of thin, highly absorbing films are distorted both by reflectance and interference phenomena. Enhanced absorbance was observed under film leaky mode conditions.
Authors: J.C. Badot
Abstract: This paper deals with the fundamental aspect of dielectric relaxations in conducting inorganic solids. It has been shown that it is possible to evidence dielectric relaxations due to charge carriers such as electrons (small-polarons) and ions, dipole reorientations (e.g. water molecules in hydrates) and to interfacial polarization phenomena (e.g. grain boundaries) in polycrystalline compounds. The importance of all these phenomena is discussed in relation to their possible interventions in dielectric spectra.
Authors: E. Antić-Fidančev, Bruno Viana, P. Aschehoug, L. Bih, A. Nadiri, M. Taibi, J. Aride
Abstract: Tungsten-phosphate glasses doped with trivalent europium ion are synthesized and their spectroscopic properties are analyzed. Following the evolution of the 5D0 → 7F1 electronic transition in a series of various glass compositions via two rank crystal field parameters (cfp’s), a slight modification of the local symmetry is evidenced in the series. Decay lifetimes of 5D1 and 5D0 levels are also analyzed. Optical properties clearly correspond to Eu3+ in the glassy phase. At room as well as at liquid nitrogen temperatures, the emission spectra display comparable features with prominent 5D0 → 7F2 transition. However, at 77 K, the maximum 7F1 splitting exhibits an increase of ≈ 20-23 % for all compounds. This increase is directly connected to a change in local environment around the rare earth ion. The optical properties and the crystal field variation could be correlated with the shortness of the metal-oxygen distances produced by the pressure when cooling.
Authors: M.D. Dramićanin, V. Jokanović, Z. Andrić, Bruno Viana, P. Aschehoug, E. Antić-Fidančev
Abstract: In view of the improvement of luminescent intensity in classical phosphors, different new techniques of synthesis have been developed. One of them is the sol-gel technique for nanopowder synthesis. Applied to a binary system Gd2O3-SiO2 doped with trivalent europium ion, very fine powder form samples have been obtained. In that case the emission intensity of 5D0→F2 electronic transition of 4f6 configuration is greatly enhanced compared to the bulk oxide. The lifetime measurements are given too. The size of nanoparticles is of about 10 nm, determined by dynamic light scattering and XRD analysis.
Authors: A. Milutinović, M.J. Romčević, N.Ž Romčević
Abstract: In Part I of this paper, we used X-ray, far-infrared reflectivity and electron paramagnetic resonance measurements to investigate optical and magnetic properties of Hg1-xMnxSe (x≤0.26) alloys. In Part II, we expand our investigation to Raman spectroscopy and galvanomagnetic measurements. We registered two-mode behaviour of long wavelength optical phonons and described it by modified Genzel’s model. Except modes from the centre of Brillouin zone, there are some of forbidden modes in Raman spectra that originate from the edge of the zone, as well as a mode that corresponds to the maximum of phonon density of states. Modes of unalloyed α–MnSe are registered, too.
Authors: Tamara Ivetić, Maria V. Nikolić, David L. Young, Dana Vasiljević-Radović, Dragan Urošević
Abstract: Thin films of single-phase zinc-stannate (Zn2SnO4) were grown by rf magnetron sputtering onto glass substrates. Transmission in the visible range was measured allowing determination of the energy gap and thickness of analyzed thin film samples using interference fringes. The photoacoustic phase and amplitude spectra of all samples were measured as a function of the laser beam modulating frequency using a transmission detection configuration. Fitting of experimental data enabled calculation of thermal diffusivity, the coefficient of minority carrier diffusion, their mobility and lifetime.
Authors: Slavica Spasović, N. Paunović, D. Popović, Jablan Dojčilović
Abstract: Far-infrared reflection spectra and results of dielectric measurements of SrTiO3 single crystal doped by neodymium are presented in the paper. Dielectric investigations were conducted at temperature range from 25 K to room temperature for the test frequency 1MHz. The numerical analysis of the far-infrared reflection spectra made using a fitting procedure based on factorized form of the dielectric function. The results for SrTiO3: Nd are compared with those for pure crystal. The lowest-frequency phonon mode is found to be strongly influenced by presence of neodymium ions in SrTiO3 single crystal.
Authors: P.D. Maguire, T.I.T. Okpalugo, I. Ahmad
Abstract: Amorphous carbon coatings for implantable medical devices require high mechanical strength, adhesion and uniform biocompatibility response across the devices. Investigation of a-C:H properties and structure variation with thickness and substrate material provides valuable insight into requirements for device coating. A number of devices are coated and the effect of interfacial layers, film doping and the spatial variation in quality is investigated.
Authors: D. Raković, M. Dugić, M.B. Plavšić, G. Keković, Irena Ćosić, David Davidović
Abstract: Our recently proposed quantum approach to biomolecular recognition processes is hereby additionally supported by biomolecular Resonant Recognition Model and by quantum-chemical theory of biomolecular non-radiative resonant transitions. Previously developed general quantumdecoherence framework for biopolymer conformational changes in very selective ligandproteins/ target-receptors key/lock biomolecular recognition processes (with electron-conformational coupling, giving rise to dynamical modification of many-electron energy-state hypersurface of the cellular quantum-ensemble ligand-proteins/target-receptors biomolecular macroscopic quantum system, with revealed possibility to consider cellular biomolecular recognition as a Hopfield-like quantum-holographic associative neural network) is further extended from nonlocal macroscopicquantum level of biological cell to nonlocal macroscopic-quantum level of biological organism, based on long-range coherent microwave excitations (as supported by macroscopic quantum-like microwave resonance therapy of the acupuncture system) - which might be of fundamental importance in understanding of underlying macroscopic quantum (quantum-holographic Hopfieldlike) control mechanisms of embryogenesis/ontogenesis and morphogenesis, and their backward influence on the expression of genes.
Authors: Dj. Koruga, A. Tomić, Z. Ratkaj, L. Matija
Abstract: Investigation of the properties of peptide plane in protein chain from both classical and quantum approach is presented. We calculated interatomic force constants for peptide plane and hydrogen bonds between peptide planes in protein chain. On the basis of force constants, displacements of each atom in peptide plane, and time of action we found that the value of the peptide plane action is close to the Planck constant. This indicates that peptide plane from the energy viewpoint possesses synergetic classical/quantum properties. Consideration of peptide planes in protein chain from information viewpoint also shows that protein chain possesses classical and quantum properties. So, it appears that protein chain behaves as a triple dual system: (1) structural - amino acids and peptide planes, (2) energy - classical and quantum state, and (3) information - classical and quantum coding. Based on experimental facts of protein chain, we proposed from the structure-energy-information viewpoint its synergetic code system.

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