Toward molecular magnets: the metal-radical approach
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The viscosity of nematic liquid crystals
A simultaneous examination of data on the dynamic, kinematic, and rotational viscosities of nematic liquid crystals (NLC) belonging to 320 chemical classes has been carried out for the first time. The methods for the measurement of the viscosities of the NLC have been subjected to a comparative analysis and the limits…
Passivation of defects in polycrystalline superlattices and quantum well structures
In order to broaden the available materials for superlattices and quantum well structures, well-passivated polycrystalline semiconductors and amorphous oxides such as pc-Si/a-SiO2, pc-Ge/a-GeO2 (pc: polycrystalline; a: amorphous) are proposed. Crucial in maintaining long scattering length involves the passivation of p…
A study of the magnetic transitions in CuO: specific heat (1-330 K), magnetic susceptibility and phonon density of states
The specific heat C p (1-330 K) and magnetic susceptibility χ (5-250 K) of a CuO sample sintered and annealed in oxygen are presented. In contrast with some earlier results, we find: (i) an essentially zero linear term in the low-temperature specific heat (γ* < 0.05 mJ mol -1 K -1 ); (ii) a minor change in slope in th…
Non-collinear itinerant magnetism: the case of Mn3Sn
Spin-density functional theory is applied to describe non-collinear itinerant magnetism. For this the theory is formulated and a new implementation is given. It serves to perform self-consistent energy-band calculations for the compound Mn 3 Sn which possesses a triangular magnetic structure. Our results are discussed…
Parity-breaking transitions of modulated patterns in hydrodynamic systems
A model for subcritical parity-breaking bifurcation of a periodic pattern is introduced. It is found that nucleated regions of the new asymmetric state propagate with a well-defined velocity in a direction determined by their parity, and leave in their wake a pattern with an altered wavelength. Successive passage of t…
Fingering instability of spinning drops
We report a study of a fingering instability which occurs during the spreading of a spinning drop. We measure the time evolution of the drop profile, the critical radius for instability onset, and the fastest growing instability wavelength. The experimental results are compatible with the predictions of lubrication th…
Quantized Hall effect and a new field-induced phase transition in the organic superconductor (TMTSF)2PF6
We report a Hall effect and magnetoresistance study of sin- gle crystals of the organic superconductor tetramethyl-tetraselenafulvalinium hexafluorophosphate, (TMTSF${)}_{2}$${\mathrm{PF}}_{6}$, under hydrostatic pressure at temperatures down to 0.5 K in magnetic fields up to 25 T. There is clear evidence for a quanti…
Refined atomic model of glutamine synthetase at 3.5 A resolution.
An atomic model of 43,692 non-hydrogen atoms has been determined for the 12-subunit enzyme glutamine synthetase from Salmonella typhimurium, by methods of x-ray diffraction including restrained least-squares atomic refinement against 65,223 unique reflections. At 3.5 A resolution the crystallographic R-factor (on 2 si…
Electrical properties of semiconducting amorphous copper-tellurite glasses
The temperature dependence of the electrical properties of the semiconducting amorphous copper-tellurite glasses is presented in a range of compositions. A polaronic model is shown to be generally applicable, and the variation of activation energy with the glass composition is found to dominate the conductivity. In pa…
Direct observation of charge-inducedπ-electronic structural changes in a conjugated polymer
Ultraviolet photoelectron spectroscopy (UPS) has been used to observe changes in the \ensuremath{\pi}-band structure in poly(3-hexylthiphene) induced by doping using ${\mathrm{NOPF}}_{6}$. The charge-induced movement of the Fermi energy and a finite density of electronic states at the Fermi energy in the most highly d…
Diluted magnetic III-V semiconductors
A new diluted magnetic III-V semiconductor of ${\mathrm{In}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Mn}}_{\mathrm{x}}$As (x\ensuremath{\le}0.18) has been produced by molecular-beam epitaxy. Films grown at 300 \ifmmode^\circ\else\textdegree\fi{}C are predominantly ferromagnetic and their properties suggest the…
Ionene elastomers from polytetramethylene oxide diamines and reactive dihalides. I. Effect of dihalide structure on polymerization and thermal reversibility
Abstract The reaction of α,ω‐bis(dimethylamino) polytetramethylene oxide with various dihalides provided a series of elastomeric ionenes. The influence of dihalide structure on the reaction was studied and a number of substituents were found which dramatically increased the rate of polymerization and ultimate molecula…
On the number dependence of viscosity in three dimensional fluids
We compute the shear viscosity of three dimensional simple fluids using nonequilibrium molecular dynamics. We show that for systems of 256 particles or more, the shear viscosity is, within ½ per cent, independent of the number of particles used in the simulation. We estimate that the zero shear rate viscosity of the t…
Studies on the polyblends of poly(vinyl chloride) with various methacrylate copolymers, melt rheological properties. II
Abstract Studies have been made on the melt rheological properties of poly(vinyl chloride) (PVC) with copolymers of methyl methacrylate (MMA) and methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA), and 2‐ethyl hexyl acrylate (EHA) at a blending ratio of 80:20. Effect of blend composition on shear stress–sh…
Structure‐property behavior of elastomeric segmented PTMO–ionene polymers. II
Abstract A series of segmented ionene polymers based on the reaction of α,ω‐bis(dimethyl amino)polytetramethylene oxide with various dihalide compounds were investigated with respect to their structure–property behavior. The placement of quaternary ammonium ions and halide counterions along the polymer chains was vari…
Effect of alkali on filaments of poly(ethylene terephthalate) and its copolyesters
Abstract The alkali hydrolysis of poly(ethylene terephthalate), anionic copolymer of poly(ethylene terephthalate), and block copolymer of poly(ethylene terephthalate)–poly(ethylene glycol) is investigated under a variety of conditions of alkali concentration in aqueous bath, additives, time, and temperature. Measureme…
Orientation in composite of polypropylene and talc
Abstract X‐ray diffraction and microscopical investigation of test samples prepared by injection molding from composites of isotactic polypropylene with talc revealed a preferred orientation of the talc and polypropylene matrix. Contrary to the situation in polypropylene alone, the preferred orientation in polypropyle…
Identification of an isoaspartyl linkage formed upon deamidation of bovine calbindin D9k and structural characterization by 2D proton NMR
Preparations of recombinant bovine calbindin D9k (r-calbindin) that appear homogeneous on SDS electrophoresis gels have been shown by isoelectric focusing to be mixtures of proteins differing in net charge. The production of two isoforms with increased negative charge occurs during a routine urea denaturation step and…
Effect of annealing on structure and electrical conductivity of evaporated indium telluride
Stoichiometric and amorphous thin layers of In2Te3 are obtained by vacuum thermal evaporation on glass substrates preheated at 300 °C. Annealing under nitrogen atmosphere modify the film structure. The best annealing conditions are determined to obtain polycrystalline films of In2Te3 with preferential orientation [111…