Materials Literature
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Abstract Novel linear and three‐arm star radial thermoplastic elastomers (TPE) comprising rubbery polyisobutylene (PIB) center blocks connected to glassy poly( p ‐chlorostyrene) (PpClSt) outer blocks have been synthesized by sequential monomer addition. For triblock polymer synthesis isobutylene (IB) was added continu…
Granular material perceived as a collection of particles is modeled as a macrocontinuum. The model takes into account the effects of microdiscreteness and the interparticle contact properties in the system. With consideration of particle rotation, the continuum model for granular solid is found to be of micropolar typ…
A small fraction of relatively insoluble gas effectively inhibits rapid coarsening of a liquid/gas foam. This effect, which is of particular practical importance in the brewing industry, is explained and simulated. Below a certain critical concentration of the insoluble gas, an inhomogeneous structure is formed. The c…
High-voltage Schottky diodes have been fabricated on diamond epitaxial films with the structure: metal/undoped diamond/p + -type diamond. The films were epitaxially grown on synthesized single-crystal diamonds (100) by microwave plasma-assisted chemical vapor deposition (CVD) using H 2 and CH 4 . B 2 H 6 was used at B…
The phosphorylation and activation of tyrosine hydroxylase was examined in PC12 cells following depolarization with KCl or treatment with nerve growth factor. Both treatments activate tyrosine hydroxylase (TH) and increase enzyme phosphorylation. Site-specific analysis of the tryptic phosphopeptides of TH isolated fro…
Abstract A series of polyamide‐azomethine‐ethers was prepared by condensation of 4,4′‐diaminoanilide with 4,4′‐diformyl‐α,ω‐diphenoxyalkane, 4,4′‐diformyl‐3,3′‐methoxy‐α,ω‐diphenoxyalkane, and 4,4′‐diformyl‐3,3′‐ethoxy‐α,ω‐diphenoxyalkane, respectively. The inherent viscosities of polymers were obviously increased whe…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTVersatile methods for the synthesis of differentially functionalized pentaerythritol amine derivativesT. Jeffrey Dunn, William L. Neumann, Milorad M. Rogic, and Steven R. WoulfeCite this: J. Org. Chem. 1990, 55, 26, 6368–6373Publication Date (Print):December 1, 1990Publicati…
The evaporative decomposition of solutions method was used to form V 2 O 5 . Spraying above the congruent melting temperature of V 2 O 5 (690°C) resulted in dense spherical particles with a smooth surface. Spraying below the V 2 O 5 melting temperature yielded porous V 2 O 5 powder with a rough surface. Reduction of t…
Four new series of biforked mesogens derived from 3,4-dialkoxybenzoic acids or 3,4-dialkoxybenzaldehydes have been prepared and studied. These derivatives exhibit an interesting polymorphism in which both columnar and lamellar mesophases exist in the same series and in some cases in the same compound. The short chain…
Time‐dependent deformation behavior induced by an indentation, called indentation creep, was investigated for Na 2 O · 3SiO 2 glasses with various water contents by measuring the indentation depth as a function of time using a conical indenter. It was found that the indentation creep behavior of the glasses could be b…
ADVERTISEMENT RETURN TO ISSUEPREVArticlePerfluoroalkylene-activated poly(aryl ether) synthesisJeff W. Labadie and James L. HedrickCite this: Macromolecules 1990, 23, 26, 5371–5373Publication Date (Print):December 1, 1990Publication History Published online1 May 2002Published inissue 1 December 1990https://pubs.acs.org…
Monazite‐type CePO 4 powder (average grain size 0.3 μm) was dry‐pressed to disks or bars. The green compacts began to sinter above 950°C. Relative density ≧ 99% and apparent porosity <1% were achieved when the specimens were sintered at 1500°C for 1 h in air. The linear thermal expansion coefficient and thermal con…
A new type of chiral discotic liquid crystal is described. It is based on a triphenylene core but carries only one asymmetric side chain per mesogen. This system displays a columnar liquid-crystalline mesophase with a helical superstructure and a pitch of 3·0 nm over a temperature range of 227 K. Upon cooling it forms…
On average 110 coupled metallocycles are present in an oligomer stack when the phthalocyaninatoiron complex 1, R1 R2 2-Et-C6H12, is allowed to react with benzene diisocyanide. This and other oligomers could be characterized by 57Fe-Mössbauer and NMR spectroscopy.
Abstract The shear modulus and loss of ca. 30% crystalline nylon‐12 have been measured over the temperature range 100–440 K and frequency range 10 −4 −1 Hz. The effect of water and physical aging of the amorphous regions on the relaxation spectra have been investigated. Absorbed water decreases both the temperature an…
The combination of porphyrin and acetylene chemistry leads to interesting novel molecules. This is illustrated by the synthesis of the first acetylene-cumulene-porphyrinoid 1, which can be regarded as a stretched porphycene.
Abstract The electrochemical properties of phenolic resin-based activated carbon fiber cloth (ACFC) in an aqueous electrolyte and in a nonaqueous organic electrolyte have been investigated. The differential electric double-layer capacitance of ACFC with the specific surface area of 1630 m2 g−1 in the aqueous electroly…
Hans Fischer's octaethylporphyrin (OEP) is so far the best available and most investigated of all synthetic porphyrins. The bisvinylogue OEP 1 has now been synthesized in high yields in a few steps. Owing to its chemical stability, good accessibility, and hitherto most intense UV/VIS absorption for an organic dye, thi…
La transformation de phase, qui s'etend sur plus de 600K, s'effectue en deux etapes. De faibles deplacements d'atomes, associes a des ellipsoides thermiques hautement anisotropes, indiquent un caractere displacif pour le debut de la transformation. Ensuite les deux structures restent presque inchangees, la transformat…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPlanar tetracoordinate carbon in zirconocene complex Cp2Zr(.mu.-.eta.1,.eta.2-Me3SiCCPh)(.mu.-Cl)AlMe2Gerhard Erker, Roland Zwettler, Carl Krueger, Ralf Noe, and Stefan WernerCite this: J. Am. Chem. Soc. 1990, 112, 26, 9620–9621Publication Date (Print):December 1, 1990Public…