Materials Literature
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A series of alkyl and dialkylammonium polyacrylates were synthesized by neutralizing a 5000 molecular weight poly(acrylic acid) with alkyl- and dialkylamines. Their thermal stability was investigated using thermogravimetry. Their thermotropic liquid crystal behavior was analyzed using differential scanning calorimetry…
Reactions of nitridomanganese(V) porphyrins with chromium(III) porphyrins resulted in the irreversible formation of nitridochromium(V) porphyrins and manganese(III) porphyrins. The progress of these reactions has been followed spectrophotometrically, electrochemically, and spectroscopically by EPR. Kinetic analysis of…
Near-threshold photoelectron recapture due to postcollision interaction with a single Auger electron is examined within the quantum-mechanical framework of radiationless resonant Raman scattering. Model calculations using a hydrogenic approximation are performed, revealing general features of the escape probability as…
Water vapor adsorption and liquid penetration into thermally oxidized porous silicon films were studied by variable angle spectroscopic ellipsometry. Characterization of the surfaces in air combined with multilayer optical modeling showed the existence of a gradient in the volume porosity and bulk‐like silicon skeleto…
The crystal structures of potassium tetratellurite and potassium ditellurite are reported, completing the series of known phases of alkali tellurites including lithium, sodium, potassium and cesium. Potassium tetratellurite (K 2 Te 4 O 9, a = 7.572(1) Å, b = 17.821(3) Å, c = 7.829(1) Å, β = 108.62°, monoclinic, P 2 1…
Abstract The constant rate stretching of amorphous poly(ethylene terephthalate) films is the first step of the industrial “inverse” process. To study this process, films deformed under uniaxial planar symmetry conditions have been produced on a laboratory stretching machine in order to discuss the influence of macrosc…
Abstract A new family of cone‐shaped podands and barrel‐shaped cryptands based on calix[4]arenes incorporating 5,5′‐substituted 2,2′‐bipyridine subunits were prepared and characterized. The Eu 3+ and Tb 3+ complexes of the podands bearing two, three, or four bipyridine chromophores could be isolated. High molar absorp…
The Fourier transform infrared (FTIR) spectra and Raman spectra of fluorine-doped silicon oxide films capped by silicon nitride thin film to prevent water absorption from the air were measured as a function of the fluorine concentration in the films. It was found that fluorine doping diminishes the Si–OH bonds in film…
During the study of the electrostatic spray deposition technique, porous LiCoO 2 thin layers with reticular structures were formed. This discovery has been successfully extended to many other important ceramic materials used in electrochemical devices such as LiMn 2 O 4 , LiNiO 2 , LiCoO 2 , Li 3 PO 4 , Li 0.1 BPO 4 ,…
A simple method for preparing thin dichroic metal composite films is described. Alkanethiol-derivatized gold particles are incorporated into poly(tetrafluoroethylene) (PTFE) matrixes that have been friction-transferred onto glass slides. Exposure of these gold particle/PTFE composites to flame (ca. 1700 °C) leads to s…
A series of linear copolymers of DTPA-class Gd3+ conjugates, linked by alpha, omega-alkyldiamides with a varying number (n) of methylenes separating the amide function, were synthesized. Surprisingly, their relaxivities at all fields increased with increasing n. At MRI fields and 35 degrees C, the relaxivities of the…
Phase diagrams for aliphatic alcohols + magnesium sulfate + water were measured. The alcohols used were ethanol, 1-propanol, 2-propanol, and 2-methyl-2-propanol. Phase diagram data were obtained at 25 °C, and for magnesium sulfate + ethanol + water at 25 °C and 35 °C.
The allowable range of marginal variation of the cell gap to ensure uniform optical properties when using in-plane switching (IPS) of liquid crystals was evaluated quantitatively. The analysis yielded relationships of transmittance into the cell gap in bright, selected bright and selected intermediate states. The sele…
The biodegration behavior of polycaprolactone–poly(ethylene glycol) block copolymer (PCL–b–PEG) was identified by degradation tests in vitro and in vivo. The tests in vitro and in vivo were carried out by immersing samples in pH 5.0, 7.2 and 9.0 buffer solutions with or without lipase at 25.0, 37.0 and 50.0±°C, and im…
The collapse and recrystallization of zinc-exchanged sodium zeolite-A has been observed in situ using combined X-ray spectroscopy and diffraction. The temperature at which this occurs is reduced by the presence of zinc, but the precipitation of NaAlSiO 4 (nepheline) is blocked by the nucleation of ZnAl 2 O 4 (gahnite)…
Strontium titanate sol was prepared using strontium ethyl haxanoate and titanium isopropoxide. The sol was then spin coated on fused silica, p-type single-crystal silicon wafers (100) and stainless-steel substrates and annealed to give polycrystalline, transparent, and crack-free films. The surface morphology and stru…
The structures of the liquid, glass (i.e., amorphous), rotator-phase (RP) crystal, orientational glass (OG), and the stable (monoclinic) crystal phases of ethanol are investigated by means of neutron and x-ray diffraction. The RP crystal and OG phases show an intermediate kind of disorder between that of the fully dis…
The effect of an initial coarsening step (50‐200 h at 800°C) on the subsequent densification and microstructural evolution of high–quality compacts of undoped and MgO–doped Al 2 O 3 has been investigated during fast–firing (5 min at 1750°C) and during constant–heating–rate sintering (4°C/min to 1450°C). In constant–he…
Abstract 2,3,7,8,12,13,17,18‐Octafluoro‐5,10,15,20‐tetraphenylporphyrin has been prepared from 3,4‐difluoropyrrole and benzaldehyde under Lindsey conditions. An X‐ray crystal structure study of its Zn II complex has shown that the macrocycle core is nonplanar, a result in apparent contradiction with a blue‐shifted UV/…
Two lamellar (L1, L2) and one hexagonal (H) vanadium oxide−dodecylamine mesophases have been prepared and characterized by XRD, FTIR, SEM, TEM, and NMR spectroscopy. The local environment of vanadium species was found to be controlled mainly by the synthesis temperature regardless of the nature of the mesophase. It wa…