Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMultiphase structure of segmented polyurethanes: effects of hard-segment flexibilityYingjie Li, Zhiyong Ren, Ming Zhao, Huichang Yang, and Benjamin ChuCite this: Macromolecules 1993, 26, 4, 612–622Publication Date (Print):February 1, 1993Publication History Published online1…
A hierarchical structural classification is developed for the copper oxysalt minerals, based on the polymerization of coordination polyhedra of higher bond valences, and focusing specifically on [3]-, [4]-, [5]- and [6]-coordinate polyhedra. The nature of copper oxysalt structures is complicated by the extremely disto…
The PEEK glass transition (alpha-relaxation) is studied as a function of polymer semicrystalline morphology, characterized by small-angle X-ray scattering. An inverse relationship is observed between glass transition temperature and amorphous interlayer thickness. This is interpreted in terms of configurational entrop…
Muscle cramps induced by voluntary contraction and by electrical stimulation of the peripheral nerve were studied electrophysiologically in 10 healthy subjects. The aim was to verify that cramps can be evoked by electrical stimulation of peripheral nerve and to clarify the physiological mechanism responsible by analyz…
94 Monomeric units make up 1, the largest pure hydrocarbon yet characterized (C1134H1146). The compound which, thanks to its di-tert-butyl-phenyl groups, is extremely soluble in pentane (!) was obtained from the monodendron precursor and triiodobenzene with a Pd catalyst in 37% yield. Elemental analysis and 1H NMR spe…
The microstructure of ZnO powder, obtained from thermal decomposition of the oxalate and studied previously by electron microscopy and adsorption calorimetry, was investigated by means of X-ray powder diffraction pattern decomposition. A Williamson–Hall plot revealed that some lines were broadened solely due to the ef…
It is well known that compression causes insulators and semiconductors to become metallic when the concentration of the matrix atoms (or of impurity atoms) reaches a critical value given by the theories of Herzfeld, Mott, Hubbard, Edwards and Sienko, and others. It is argued here, based on the observed transitions in…
Endgrafted polymers at surfaces exposed to a shear flow are modeled by a nonequilibrium Monte Carlo method where the jump rate of effective monomers to neighboring lattice sites against the flow direction is smaller than in the flow direction, assuming that this difference in jump rates is proportional to the local ve…
The dynamic mechanical properties of low density polyethylene filled with isocyanate treated and untreated short sisal fiber composites were studied as a function of temperature and frequency. By the incorporation of short sisal fiber into LDPE, the stor age moduli ( E') and loss moduli ( E") increase, whereas the mec…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXT4,6-Dimethoxy-1,3-phenylenebis(N-tert-butyl nitroxide) with a singlet ground state. Formal violation of a rule that m-phenylene serves as a robust ferromagnetic coupling unitFumio Kanno, Katsuya Inoue, Noboru Koga, and Hiizu IwamuraCite this: J. Am. Chem. Soc. 1993, 115, 3,…
We used transposon (Tn) mutagenesis to study the role of capsular polysaccharide/adhesin (PS/A) and slime in adherence of Staphylococcus epidermidis to catheters. pLTV1, containing Tn917-LTV1, was transformed into S. epidermidis M187 by protoplast fusion with S. aureus RN4220(pLTV1), creating M187(pLTV1). Tn mutants w…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMechanistic studies of copper thin-film growth from CuI and CuII .beta.-diketonatesGregory S. Girolami, Patrick M. Jeffries, and Lawrence H. DuboisCite this: J. Am. Chem. Soc. 1993, 115, 3, 1015–1024Publication Date (Print):February 1, 1993Publication History Published onlin…
The sedimentation of monodisperse suspensions of rigid spheres has been studied by dynamical simulation; computational techniques are described and numerical results are reported. It has been found that there is a slow relaxation of the suspension microstructure during sedimentation, so that compared with the initial…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMorphology transition from cylindrical to lamellar microdomains of block copolymersShinichi Sakurai, Toshikazu Momii, Kazuhiro Taie, Mitsuhiro Shibayama, Shunji Nomura, and Takeji HashimotoCite this: Macromolecules 1993, 26, 3, 485–491Publication Date (Print):February 1, 199…
It appears that, under suitable conditions, diatom assemblages can respond very quickly to a toxic event. The data suggest an inoculum of cells from the water column can multiply rapidly. Sediment-inhabiting macrofauna are more seriously affected, reducing grazing restrictions on the developing diatom assemblages. The…
The beginning–or the end—of the metallic state is attained in ligand‐stabilized Au 55 clusters. As quantum dots with two last “switchable” electrons they are the nonpareils of electronic miniaturization and can be used as microelectronic quantum devices.
Using proteolytic susceptibility as a probe, we have identified four regions of the actin polypeptide chain where structural rearrangements, dependent on the nature of the tightly bound metal ion and/or nucleotide, take place. Replacement of the tightly bound Ca2+ by Mg2+ in ATP-actin strongly affected the regions aro…
The melting transition of particles interacting via a Yukawa potential is determined from the evolution of systems containing coexisting solid and fluid phases. There is no nucleation barrier, and the stable phase expands rapidly to fill the system. Results for the phase boundary agree with recent free energy calculat…
A systematic investigation of the intrinsic magnetic properties of R${\mathrm{Fe}}_{11}$Ti compounds with R=Y, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Tm has been performed by means of ac-susceptibility measurements, singular-point-detection techniques, and high-field magnetization measurements. Spin-reorientation transit…
A drop-tube-processed Al-3.6wt.%Fe representative droplet of about 500 μm diameter shows the two-zone fine cellular-coarse cellular α-Al structure, hitherto reported only in as-atomized hypereutectic AlFe powder particles of less than 50 μm diameter. The origin of the transitional microstructure is analysed in terms…