Materials Literature
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SummaryZinc-manganese has consistently attracted researchers as potentially the most corrosion resistant zinc alloy coating but to date is the most under-developed and yet to be commercially exploited to any significant degree. This paper reviews the current status of this alloy, outlining the research that has been c…
Phase formation and dielectric properties of the compositions in the system [Pb(Fe 1/2 Nb 1/2 )O 3 ] 1 _ x –[Pb(Zn 1/3 Nb 2/3 )O 3 ] x were investigated as possible materials for multilayer ceramic capacitors. The formation of the phase with perovskite structure and dielectric properties of ceramics at room temperatur…
Formation of rounded forms of carbon offers a unique opportunity to study the properties of materials constrained in nanoscale environments. Encapsulation of molybdenum carbide in polyhedral carbon nanoparticles is found to stabilize the face-centered-cubic form at the expense of the commonly encountered hexagonal-clo…
The electron spin resonance spectra of Mn 2+ exchanged zeolite A have been investigated as a function of the monovalent co-cation (K +, Na +, Li +, Cs +, or NH 4 + ), Mn 2+ content, recording frequency, and temperature. Three new Mn 2+ species are observed with a well-resolved fine structure; this allows for the first…
New examples of polyoxometalate-anion-pillared layered double hydroxides have been prepared by ion exchange and direct synthesis methods and characterised by powder X-ray diffraction, extended X-ray absorption fine structure (EXAFS), IR and UV/VIS spectroscopy. Complete conversion into crystalline phases was achieved…
Direct NMR measurements of the folding kinetics are performed on a collagen-like triple helical peptide. The triple helical peptide was designed to model a biologically important region of collagen and has the sequence (POG)3ITGARGLAG(POG)4. Triple helical peptides were synthesized with specifically labeled 15N amino…
Aryloxo derivatives of phosphorus(V) porphyrins of the type [(TpTP)P(OR)(2)](+)OH(-) where TpTP is the dianion of tetra-p-tolylporphyrin and OR is an axial aryloxo (2,4-dimethylphenoxo, 4-methylphenoxo, phenoxo, 4-nitrophenoxo, 4-(4-nitrophenoxy)phenoxo, or 4-(2,4-dinitrophenoxy)phenoxo) ligand have been synthesized a…
Relaxation processes in nonlinear optical modified polyimide polymers with side-chain azo chromophores having glass transition temperatures in the range of 140 < T g < 170 °C have been studied. The relaxational mechanisms of the side-chain chromophores in these polymers have been investigated above and below the glass…
Difunctional aminophenylenethienylidene-1,3-bis(dicyanomethylidene)indane (APT-BDMI) based second-order nonlinear optical materials have been synthesized and characterized. The BDMI-based NLO chromophores studied here demonstrate excellent chemical stability under ambient and poling conditions. The electrooptic coeffi…
The reaction between ZnEt2 and 2 equiv of sulfur in toluene followed by workup in pyridine (py) results in isolation of Zn10S4(SEt)12(py)4 (2) and [Zn2S(SEt)(Et)py]n. Species 2 reacts with an excess of lutidine to yield Zn10S4(SEt)12(lutidine)4 (1), which was characterized in the solid state and is the first example o…
Electron spin resonance (ESR) spectroscopy has been used to obtain information on chain mobility in spin-doped poly[styrene- co -(sodium methacrylate)] random ionomers. The results show that spin probe molecules randomly dispersed in ionomers respond to the matrix glass transition. However, when the probe molecules ar…
Doping-dependent contrast in secondary electron images of p/n junctions in silicon obtained in a field-emission scanning electron microscope was observed and characterized. The optimum experimental conditions for observing this ‘‘electronic’’ contrast were established by investigating the effect of microscope and mate…
The goal of our work was to design in a controlled manner open-shell supramolecular assemblies with dominant intermolecular ferromagnetic interactions. Along this line, the compounds of formula rad 6 M(CN) 6 I 3 · 2H 2 O with M = Cr, Fe, and Co have been synthesized; rad + stands for the 2-(3- N -methylpyridinium)-4,4…
An improved model is presented which simulates temporal behavior in the CO + O 2 reaction on the Pt{100} surface. The model is based on an experimentally determined strongly nonlinear power law for (1 × 1)-CO island growth rate from the hexagonal (hex) phase with an apparent reaction order of about 4 in the local CO c…
A combination of high resolution X-ray diffraction and molecular modelling techniques have been used to determine (Rwp= 12.51%) the crystal structure of the X-form of metal-free phthalocyanine. It was found to crystallise in a bimolecular monoclinic unit cell (space group P21/a) with lattice parameters a= 10.63, b= 23…
Polycrystalline diamond films were deposited in a MW-PECVD reactor employing bias-enhanced nucleation as pretreatment to promote the subsequent diamond nucleation. The substrate temperature during the bias-enhanced nucleation was varied between 600° and 760 °C by external heating, while the other deposition parameters…
Sonodynamically induced lipid peroxidation with haematoporphyrin (Hp) was studied using rat erythrocytes. Both suspensions of erythrocyte ghosts and of intact erythrocytes were exposed to ultrasound in the same way in the presence and absence of Hp (80 microM). The lipid peroxidation in erythrocyte ghost membranes was…
A novel polynuclear Mo−Cu cluster compound (Et4N)4[MoS4Cu10Cl12] has been synthesized by the reaction of (NH4)2[MoS4], Et4NCl, and CuCl in acac/DMSO. The reaction mechanism has been monitored by dynamic 95Mo NMR spectra. X-ray single-crystal diffraction analysis reveals that the anion structure consists of a central M…
Electrochemical behavior of dopamine and ascorbic acid binary mixture was examined by cyclic voltammetry and the analysis of a each component was performed by differential pulse voltammetry. The electrochemical behavior of these molecules on poly-3-methylthiophene, polypyrrole, polyaniline electrodes were compared. Th…
Dynamic light scattering measurements have been performed on four symmetric diblock copolymer melts, as a function of temperature, both above and below the order−disorder transition (ODT). The materials were poly(ethylenepropylene)−poly(ethylethylene) (PEP−PEE) with M w = 5.0 × 10 4, poly(vinylcyclohexane) (PVCH)−PEE…