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Der Punkt auf dem i / Icing on the Cake
Erdöl und Erdgas: Ein weites Betätigungsfeld für Rheologen / Petroleum and natural gas: An extensive sphere of activity for rheologists
Electrochemical Formation of Polyaniline in Selenic Acid
The electrochemical formation of polyaniline (PAn) was investigated in selenic acid. The cyclic voltammetry of selenate in the potential window from −0.15 to 0.8 V, indicates that the electropolymerization of aniline is not affected by the oxidizing ability of selenic acid. The growth rate of PAn observed at a potenti…
Static and dynamic Jahn-Teller effects in Cu (super 2+) oxysalt minerals
The details of Jahn-Teller distorted Cu (super 2+) phi 6 (phi : O (super 2-) , OH (super -) , H 2 O) octahedral geometries in Cu (super 2+) oxysalt minerals are examined. Usually the Cu (super 2+) phi 6 octahedron is (4+2)-distorted, although both (2+4)-distorted and holosymmetric octahedra have been reported in miner…
An Organosulfur Polymer Cathode with a High Current Capability for Rechargeable Batteries
The charge‐discharge capability of a polymer composite cathode prepared from 2,5‐dimercapto‐1,3,4‐thiadiazole (DMcT), polyaniline, S‐alkylcarboxylate‐4‐methylpyrrole, and acetylene black has been investigated on different kinds of current collectors including copper, nickel, aluminum, and titanium foil, gold‐plated ti…
Purification and characterization of two reversible and ADP-dependent acetyl coenzyme A synthetases from the hyperthermophilic archaeon Pyrococcus furiosus
Pyrococcus furiosus is a strictly anaerobic archaeon (archaebacterium) that grows at temperatures up to 105 degrees C by fermenting carbohydrates and peptides. Cell extracts have been previously shown to contain an unusual acetyl coenzyme A (acetyl-CoA) synthetase (ACS) which catalyzes the formation of acetate and ATP…
Raman Study of the Relationship between Room‐Temperature Tetragonality and the Curie Point of Barium Titanate
Variable‐temperature Raman spectroscopy showed that, in progressively finer BaTiO 3 powders, the Curie point increased as the room temperature tetragonality decreased. The influence of crystallite size distribution on the range of tetragonalities present in a powder was clearly evident in both phase transitions, as ob…
Statistical Mechanics of Cracks: Thermodynamic Limit, Fluctuations, Breakdown, and Asymptotics of Elastic Theory
We study a class of models for brittle fracture: elastic theory models which allow for cracks but not for plastic flow. We show that these models exhibit, at all finite temperatures, a transition to fracture under applied load similar to that at a first order liquid-gas transition. We study this transition at low temp…
The effect of monomer evaporation on a simple model of submonolayer growth
We present a model for thin film growth by particle deposition that takes into account the possible evaporation of the particles deposited on the surface. Our model focuses on the formation of two-dimensional structures. We find that the presence of evaporation can dramatically affect the growth kinetics of the film,…
Spectroscopic data of the 18-, 29-, and 43-μm transitions in dysprosium-doped gallium lanthanum sulfide glass
Infrared emission at 1.8, 2.9, and 4.3 microm is measured in dysprosium-doped gallium lanthanum sulfide (Ga:La:S) glass excited at 815 nm. Emission cross sections were calculated by Judd-Ofelt analysis, the Füchtbauer- Ladenburg equation, and the theory of McCumber. The sigmatau value for the 4.3-microm transition is…
Effect of physical crosslinking methods on collagen-fiber durability in proteolytic solutions
We previously demonstrated that ultraviolet (UV) or dehydrothermal (DHT) crosslinking partially denatured fibers extruded from an insoluble type I collagen dispersion. In this study denaturation effects were evaluated by measuring collagen-fiber sensitivity to trypsin. Shrinkage-temperature measurements and sensitivit…
ANTIMICROBIAL AND PHYSICOCHEMICAL PROPERTIES OF METHYLCELLULOSE AND CHITOSAN FILMS CONTAINING A PRESERVATIVE
The methylcellulose was mixed with chitosan as well as 4% of sodium benzoate or potassium sorbate to form a film. Investigations of the antimycotic activity of the film on Penicillium notatum and Rhodotorula rubra revealed that it possessed significant antifungal properties. At 25C, approximately 43–45% of the preserv…
Rigid-unit phonon modes and structural phase transitions in framework silicates
The rigid-unit mode model provides many new insights into the stability and physical properties of framework silicates. In this model the SiOo and AlO4 tetrahedra are treated as very stifl to a first approximation as completely rigid, in comparison with intertetrahedral forces. In this paper we apply the model to seve…
Charge localization by static and dynamic distortions of the MnO 6 octahedra in perovskite manganites
We present transport and neutron-diffraction data establishing a clear link between static and dynamic distortions of the ${\mathrm{MnO}}_{6}$ octahedra and charge mobility in ${\mathit{A}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$A${\ensuremath{'}}_{\mathit{x}}$ ${\mathrm{MnO}}_{3}$ (A=La or Pr; ${\mathit{A}}^{\ensuremat…
Dendrimers and Hyperbranched Polymers: Two Families of Three-Dimensional Macromolecules with Similar but Clearly Distinct Properties
Dendrimers and hyperbranched polymers are globular macromolecules that are characterized both by a highly branched structure, in which all bonds converge to a focal point or core, and a multiplicity of reactive chain-ends. Because of the obvious similarity of their building blocks, many assume that the properties of t…
On the effective medium theory of subwavelength periodic structures
The effective medium theory of one-dimensional and two-dimensional periodic structures are investigated. A method based on a Fourier decomposition of the wave propagating along the direction perpendicular to the periodic structures allows one to determine the zeroth-, first- and second-order effective indices. For one…
PROTEIN CRYSTALLIZATION
Crystallization is necessary to obtain the three-dimensional structure of proteins and nucleic acids; it often represents the bottleneck in structure determination. Our understanding of crystallization mechanisms is still incomplete. In this review, we emphasize fundamental aspects of the crystallization process. Prot…
The Biosynthesis of Cellulose
Cellulose is one of the major commercial products of Sweden and constitutes the most abundant of the natural polymer systems. Thus, it is of interest to review the molecular design and architecture of cellulose with particular reference to the controls of its biosynthesis. The bioassembly process is highly ordered and…