Materials Literature
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The synthesis of meso-tetraphenylporphyrin (TPP) and its application in a solar- energy conversion device are described as an undergraduate laboratory experiment. In the first part of the exercise, a convenient procedure for the synthesis of TPP is presented. In the second section of the experiment, the construction o…
Abstract The electrical properties of SrTiO3 (strontium titanate) ceramics are strongly influenced or even dictated by grain boundary segregation of charged point defects, such as dopant atoms, impurities, vacancies, or self-interstitials. The atomistic structure of the grain boundaries, their energy, and the segregat…
Abstract Quantitative analysis with the electron microprobe analyzer (EMPA) has yielded more accurate results over time as a result of improvements in ZAF and other correction routines, mass absorption coefficients, synthetic pseudocrystals for ultralight elements, computers, software programs, backscattered electron…
Abstract A comprehensive understanding of the relation between structure and properties in nano-materials calls for an extensive knowledge of the adhesion between nanoparticles. Electron diffraction contrast from the stress field caused by adhesion between contacting particles yields a detailed information on surface…
Based on complex electro-optical and dielectric measurements, the processes of low frequency relaxation in PDLC (Polymer Dispersed Liquid Crystals) films have been studied. Experimental data are presented to investigate PDLC structure and its evolution with increase in LC concentration. These results are found to be i…
This chapter contains sections titled: Introduction Experimental Procedures Results and Discussion Conclusions Acknowledgements
The dependence of the cellular (biogenic) and frustule-associated (mineralized) silica content of the diatoms Navicula salinarum and Thalassiosira weissflogii on salinity and aluminium conditions was studied in order to make it possible to manipulate silicification in vitro and maximize it to levels required for physi…
The texture changes during the initial phase of blanching of potatoes, carrots and green peas at different blanching times (0–240 s) and temperatures (85 °C, 95 °C, 100 °C) were investigated. The breaking force (N) was determined by compression or Back extrusion tests with an Instron texture tester. Electronmicroscopi…
A model for rim porosity that takes into account the effect of overpressurization on rim pores is proposed for high-burnup UO2 fuel. It is based on the assumption that all the fission gases produced are retained in rim pores, and the threshold pellet average burnup required for the formation of the rim region is 40 MW…
Tetra(n-butyl)ammonium ds-diacidooxophthalocyaninato(2-)niobates(V) and -tantalates(V), ( n Bu 4 N) cis [M(X) 2 Opc 2- ] (M = Nb, Ta; X = F, Cl, NCS, N 3 ), are obtained by the reaction of cis [M(Cl) 3 pc 2- ] or cis [M(Cl}Opc 2- ] (M = Nb, Ta) with the respective tetra(n-butyl)ammonium salt. ( n Bu 4 N) cis [Nb(F) 2…
Abstract A new CuII-NiII heterodinuclear complex [Cu(PEoxd)Ni(bpy)2](ClO4)2·1/2H2O has been synthesized and its structure determined by single crystal X-ray analysis. Crystal data: space group P21/c with a = 9.226(2) Å, b = 30.857(6) Å, c = 14.241(3) Å, and β = 97.36(3)°, V = 4021(2) Å3, Z = 4. Magnetic measurement in…
A simple double-well potential model is established. It shows that the nature of the low-frequency dielectric constant in ferroelectrics is the additional hopping of the off-center ions in multi-site potential. The co-operative effect causes the fact that the Curie-Weiss law is obeyed. The mechanism of the molecular f…
The TL dosimetric properties of the LiF thin films produced on aluminium and stainless steel substrates has been investigated. The influence of some deposition parameters and thermal annealing on the film TL response was studied. The films were irradiated with a 60Co source with doses from 0.2 to 100 Gy. The films' TL…
The initiation and propagation of nanometre-scale cracks has been investigated in detail using dislocation modelling and in situ transmission electron microscopy (TEM) observations for the intermetallic compound Fe3Al under mode I loading. A discrete dislocation model is proposed to assess quasistatic equilibrium, emi…
The complex dielectric constant of a liquid crystal material, 4-cyano-4′-alkyl-biphenyl (5CB), in a low frequency region was measured by taking the thickness of a specimen as parameter. The results were analyzed by introducing an equivalent circuit of a novel concept by taking two kinds of contributions into account:…
The first-order hyperpolarizability β was determined for bent-shaped molecules P-8-PIMB and P-8-O-PIMB using the Hyper Rayleigh scattering method. βs of these materials were found to be relatively large, about 30×10−30 esu. These results are consistent with the second-harmonic generation experiments performed in their…
It is well known that the software Surface Evolver (SE) models the geometry of minimal surface area structures such as a foam. Here we have modelled with SE the gas-diffusion phenomenon responsible for the coarsening of liquid foams. We took as an initial condition, a real reconstructed foam obtained by optical tomogr…
Among the copper base shape memory alloys the most popular are CuZnAl alloys which however show several features like: tendency to stabilisation, limitation of the effect to low temperatures, lattice defects multiplication after numerous cycling and low decomposition temperatures. This defines the directions of invest…
The new compound hexacaesium hexatellurido digermanate(III), Cs 6 Ge 2 Te 6 , has been prepared by reacting the elements in a stoichiometric ratio at 923 K in an evacuated silica glass tube. The title compound crystallizes as black columns and is isostructural to K 6 G e 2 Te 6 (C2/c, a = 17.027(2), b = 14.237(1), c =…
Conductivity measurements on a smectic liquid crystal with terminal diol-groups are reported. The average conductivity in the liquid crystalline state exceeds the conductivity of the isotropic melt by a factor of 2. This strongly unusual behaviour supports the assumption of fast protonic conductivity in smectic diols,…