Materials Literature
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Kinetic data on the esterification of acetic acid with propyl alcohol catalyzed by the ion exchange resin DOWEX MONOSPHERE 650 C have been obtained using a stirred batch reactor. It was checked if there is an influence of pore diffusion and film resistance on the reaction rate when varying reaction temperature, initia…
Synthetic methods for [Et(4)N](4)[W(4)Cu(4)S(12)O(4)] (1), [Et(4)N](4)[Mo(4)Cu(4)S(12)O(4)] (2), [W(4)Cu(4)S(12)O(4)(CuTMEN)(4)] (3), and [Mo(4)Cu(4)S(12)O(4)(CuTMEN)(4)] (4) are described. [Et(4)N](2)[MS(4)], [Et(4)N](2)[MS(2)O(2)], Cu(NO(3))(2).3H(2)O, and KBH(4) (or Et(4)NBH(4)) were used as starting materials for…
Direct nonradiative energy transfer (DET) experiments were carried out on five polyisoprene−poly(methyl methacrylate) diblock copolymers with polyisoprene volume fractions ranging from 0.07 to 0.5 (polyisoprene microdomains dispersed in a poly(methyl methacrylate) matrix). These experiments yield the ratio R /δ of the…
The synthesis of 60−1000 Å thick films of fluorinated polymers on gold and silica substrates via amidation of layered, hyperbranched poly(acrylic acid) surface-graft films with a fluorinated octylamine is described. These syntheses proceed either by formation and fluoramidation of layers of poly(acrylic acid) or by st…
Heteronuclear complexes of the type Ln′xLn″1 –x[Co(CN)6]·nH2O have been synthesized for potential applications in solid oxide fuel cells. SmxEr1 –xCo and SmxYb1 –xCo complexes crystallize in the orthorhombic system, as do LaxSm1 –xCo complexes for x= 0-0.6. A plot of the lattice parameters of the orthorhombic structur…
Orientation correlations in a quiescently quenched, lamellar block copolymer were examined by a combination of depolarized light scattering and transmission electron microscopy. These experiments reveal exponential correlation functions with characteristic lengths that depend on the thermal history of the sample. The…
The boundary layer of PHA inclusion bodies isolated from Chromatium vinosum, Pseudomonas oleovorans, and Rhodococcus ruber was investigated by negative staining and transmission electron microscopy. A typical boundary layer exhibits a basic lattice composed of regularly arranged phasin molecules and phospholipids, for…
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…