Materials Literature
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Six Amphora species [A. affinis Kützing, A. copulata (Kützing) nov. comb., A. marina W. Smith, A. ovalis (Kützing) Kützing, A. proteus Gregory, A. robusta Gregory] belonging to the subgenus Amphora Cleve were observed on strewn slides in the British Museum (Natural History). Light microscope photographs of examples co…
The electrical resistivities and activation energies for electric conduction in glasses of the system Na 2 O-V 2 O 5 -B 2 O 3 with V 2 O 5 <15 mol.%, have been measured. Two types of conductivities are postulated: ionic conductivity in the higher temperature region and electronic conductivity in the lower temperature…
Examen des legeres differences entre les structures des phases β et α' afin d'interpreter l'apparition d'une modulation dans la transition β⇄α'
This paper describes a study of the effect of a cationic softening agent on the processes involved in pulling out a single warp yarn from a plain weave cotton fabric. In par ticular, measurements are made of the pull-out force and the corresponding yarn and fabric deformations, and these parameters are compared with t…
We consider random interfaces generated by level crossing of a Gaussian random field. Transition from an isolated pattern to a percolating one is discussed by calculating the Euler characteristics of the interface and the number of local minimum of the generating Gaussian field. These topological invariants are shown…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPromotion effects of vanadium, niobium, molybdenum, tungsten, and rhenium oxides on surface reactions in the carbon monoxide hydrogenation over ruthenium/aluminum oxide catalystToshiaki Mori, Akira Miyamoto, Naoki Takahashi, Masato Fukagaya, Tadashi Hattori, and Yuichi Murak…
A method for measuring the specific heat of small samples at low temperatures is described. In this method C p is evaluated by directly comparing the heating and cooling rates of the sample temperature without explicit use of the thermal conductance between sample and bath.
An axial gradient, infrared optical material, ZnSxSe1−x, has been developed by codepositing ZnS and ZnSe in a controlled manner via a chemical vapor deposition process. This material has been characterized by measuring the compositional and refractive-index profiles, visible, and IR transmission, microstructure, and h…
Abstract Experiments on the conversion of feldspar to illite reveal that variation of the fluid/rock ratio (flow rate) has a significant effect on the kinetics of feldspar dissolution and illite formation. Dissolution of albite in near-neutral KCl solution at 200°C and 500 bar shows that the Si and Na release rate per…
The fact that a titanium screw can be implanted into the mastoid portion of the human skull, at the same time establishing a permanent, reaction-free skin penetration, has made it possible to attach a new bone conduction hearing aid directly to the skull. To understand and improve this new method of bone stimulation,…
Foe nearly three decades people have employed an equation derived by Frenkel to describe the strain energy of an atom diffusing in a glass. This equation describes the strain energy to enlarge a spherical cavity and predicts physically unreasonable results. An alternative equation for a circularly symmetric enlargemen…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrganometallic chemistry of rhodium tetraphenylporphyrin derivatives: formyl, hydroxymethyl, and alkyl complexesBradford B. Wayland, Seth L. Van Voorhees, and Charles WilkerCite this: Inorg. Chem. 1986, 25, 22, 4039–4042Publication Date (Print):October 1, 1986Publication His…
Abstract Simplified vent sizing equations for emergency relief requirements in reaction kettles and storage vessels are obtained from analytical consideration. Venting modes include homogeneous‐vessel venting, all‐vacor venting, and all‐liquid venting; energy sources due to runaway chemical reactions and external heat…
Abstract Surface‐enhanced Raman scattering (SERS) of adenine, adenosine, 2′‐deoxyadenosine, 5′‐dAMP, 5′‐rAMP, 5′‐rADP and 5′‐rATP adsorbed on aqueous Ag sol has been investigated. A shift of the adenine ring breathing mode from 746 to 735 cm −1 with increasing adenine concentration is interpreted as reflecting the reo…
A quasicrystal may be described by its quasilattice and its atomic decoration. We discuss two different commonly used methods for decorating quasilattices which lead to inequivalent real-space structures, the tile-decoration method and the hyperlattice-decoration-and-projection method. It is shown that diffraction pat…
An interface between two phases is considered. A set of differential equations of arbitrary order is derived from a Landau-Ginzburg approach. The higher-order equations reveal more detailed structure of the interface. In particular, any anisotropy of the interactions is exhibited in the equations and the modified Gibb…
Natural mordenite (Na1.49K2.80Mg0.04Ca2.05Sr0.05)(Al8.98Si39.13)O96.29.07H2O from Elba, Italy is orthorhombic, space group Cmc21, with a 18.094(1), b 20.516(1), and c 7.524(1) Å; Z = 1. The structure was refined in its hydrated form to Rw = 5.2%. The atom O(8) is not set on an inversion center and the T-O(8)-T angle…
A high-resolution x-ray crystallographic investigation of the complex between carboxypeptidase A (CPA; peptidyl-L-amino-acid hydrolase, EC 3.4.17.1) and the slowly hydrolyzed substrate glycyl-L-tyrosine was done at -9 degrees C. Although this enzyme-substrate complex has been the subject of earlier crystallographic in…
In Bacillus subtilis, the extracellular enzyme levansurcrase is synthesized in the presence of sucrose. A termination structure between the transcription start site and the structural gene was the apparent site for regulation by sucrose of transcription into the structural gene. Sequence analysis of the sacB leader re…
The spinel phase formed on the thermal reaction of kaolin group minerals was characterized by X‐ray quantitative analysis, lattice constant determination, and chemical analysis by analytical TEM. The spinel phase was determined to be nearly γ‐Al 2 O 3 with ∼8 wt% of SiO 2 , significantly less than previously reported.