Materials Literature
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Two series of asymmetric dimers, the α-(4-n-butylanilinebenzylidene-4′-oxy)-ω-(4-nitroazobenzene-4′-oxy) alkanes and the α (4-dimethylaminoanilinebenzyl-idene-4′-oxy)-ω-(4-nitroazobenzene-4′-oxy)alkanes have been synthesized. Their thermal properties are compared with those of the symmetric dimers, the α,ω-bis(4-nitro…
Polynomial (nonsingular) dynamical trace maps of generalized Fibonacci tilings (A,B\ensuremath{\rightarrow}${\mathit{A}}^{\mathit{m}}$${\mathit{B}}^{\mathit{n}}$,A) are derived for arbitrary values of m and n. It is shown that these sequences can be grouped into two distinct classes. The sequences in class I correspon…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStabilities of trivalent metal complexes of phenolic ligands related to N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED)Ramunas J. Motekaitis, Arthur E. Martell, and Michael J. WelchCite this: Inorg. Chem. 1990, 29, 8, 1463–1467Publication Date (Print):Apri…
Abstract Acrylamide has been polymerized between the layers of kaolinite by heat treatment. Acrylamide monomer was first intercalated by the displacement reaction between a kaolinite-N-methylformamide (NMF) intercalation compound and a 10% acrylamide aqueous solution. The resulting intercalation compound showed a basa…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMetalloporphyrin-catalyzed oxidation of saturated hydrocarbons with sodium chloriteJames P. Collman, Hiroo Tanaka, Robert T. Hembre, and John I. BraumanCite this: J. Am. Chem. Soc. 1990, 112, 9, 3689–3690Publication Date (Print):April 1, 1990Publication History Published onl…
Abstract Polyoxytetramethyleneglycol (PTMG) can be directly prepared from tetrahydrofuran (THF) and water in the presence of heteropolyacids (HPA), without the hydrolysis step. The reaction is carried out by mixing two liquid phases: the THF phase and a heteropolyacid catalyst phase. In this reaction the molar ratio o…
The affects of alkoxide‐derived coatings on the bending strength of silica glass were investigated. For densified coatings, increases in strength of 120% to 130% were found. A model of the strengthening process, based on the filling‐in and partial healing of surface flaws, is proposed. The model accounts for the tempe…
Surface-enhanced Raman spectrometry (SERS) of three sulfa drugs (sulfadiazine, sulfamerazine, and sulfamethazine) is reported. Silver colloidal dispersions prepared by simple borohydride reduction of silver nitrate are used as substrates. The capability of SERS for spectral fingerprinting of analytes with close struct…
In situ x‐ray diffraction (XRD) technique was employed to study unstable phases formed in sintered or anodically oxidized tungsten and molybdenum trioxide film electrodes under electrocoloration conditions in , in order to discuss their electrochromic characteristics on the basis of structural properties. The XRD patt…
Recent evidence is summarized showing that the tetragonal ( t ) → monoclinic ( m ) martensitic transformation in ZrO 2 can occur thermoelastically in certain ZrO 2 ‐containing ceramics, and that microcracking accompanying the transformation is more common than had previously been recognized. The implications of these…
Thermal oxidation kinetics of aluminum nitride (AlN) powders, having fine‐ and coarse‐particle‐size distributions, were studied using thermogravimetric analysis (TGA). The kinetics showed dependence on the particle‐size parameter, and the experimental TGA data were curve fitted using empirical mass relations employing…
Abstract The electrical and dielectric properties of compression‐molded segregated polyethylene‐carbon black mixtures are described in the frequency range between 10 and 8000 kHz as a function of frequency, temperature, and carbon black loading. The segregated systems investigated exhibit insulator‐conductor transitio…
ABSTRACT The stimulus to growth that occurs when cells attach to the substratum can be studied with small adhesive islands. Large numbers of these islands can be grouped together into arrays made up of various sizes, and the response of cells to incubation on these arrays allows the anchorage stimulus to be measured.…
We have studied the photoemission spectra of ${\mathrm{Nd}}_{2\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Ce}}_{\mathit{x}}$${\mathrm{CuO}}_{4}$ (0.05\ensuremath{\le}x\ensuremath{\le}0.2) using synchrotron radiation in the Cu 3p\ensuremath{\rightarrow}3d, Nd 4d\ensuremath{\rightarrow}4f, and Ce 4d\ensuremath{\rightar…
Abstract Polyurethanes (PU) based on poly(butylene adipate) [PU(PBA)] and poly(oxypropylene) [PU(PPG)] polyols have bean introduced into the diglycidyl ether of bisphenol A (epoxy) to form interpenetrating polymer networks (IPNs) with a PU‐grafted epoxy structure (graft‐IPNs). The tensile strength in both PU(PPG)/epox…
Abstract Wholly aromatic polyamide‐imides with high molecular weight (η inh up to 1.7 dL/g in DMAc–5% LiCl) were obtained by the direct polycondensation reaction of N‐[p ‐( or m ‐) carboxyphenyl]trimellitimide [ p ‐(or m ‐)CPTMI] and aromatic diamines by means of di‐ or triphenyl phosphite in N ‐methyl‐2‐pyrrolidone (…
Oxidation studies were conducted on Al 2 O 3 ‐SiC and mullite‐SiC composites at 1375° to 1575°C in O 2 and in Ar‐1% O 2 . The composites were prepared by hot‐pressing mixtures of Al 2 O 3 or mullite and SiC powders. The reaction products contained alumina, mullite, an aluminosilicate liquid, and gas bubbles. The parab…
Two disc-shaped multialkynyl arene ethers (1 and 2) with unusual thermo-mesomorphic properties are presented. Conoscopic studies show that the nematic phases of these new low molecular weight liquid crystals are biaxial and that the sign of their biaxiality is negative. The diether 2 is the first discotic twin liquid…
Part 1 Dimensional instabilities due to volume relaxation: general outline of volume relaxation volume-relaxation data for a number of polymers consequences for optical and electrical properties methods to reduce the volume-relaxation effects. Part 2 Dimensional instability due to the stresses acting during processing…
Abstract New monomers are described for the synthesis of rod‐like poly(1,4‐phenyleneethynylene)s with long flexible aliphatic side chains. By palladium catalyzed polycondensation soluble polymers with melting points around 100°C could be obtained. The molecular weight was estimated by GPC, VPO and elemental analysis:…