Immersion grating for infrared astronomy
An immersion grating with high refractive index n increases spectral resolution n-fold over that of a surface reflection grating of equal length.
Materials Literature
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High‐Temperature X‐ray Study of the Cubic–Tetragonal Diffusionless Phase Transition in the ZrO 2 ─ErO 1.5 System: II, Temperature Dependences of Oxygen Ion Displacement and Lattice Parameter of Compositionally Homogeneous 12 mol% ErO 1.5 ─ZrO 2
The tetragonal‐to‐cubic phase transition of rapidly quenched 12 mol% ErO 1.5 ─ZrO 2 was investigated in situ using high‐temperature X‐ray diffraction. Rapid quenching of the melt yielded a small oxygen ion displacement and a small tetragonality, axial ratio c/a . Although the tetragonality of the as‐quenched specimen…
Palygorskite in the recent fluvio-lacustrine and deltaic sediments of southern Mesopotamia
Palygorskite has been widely reported as a clay phase in the Recent sediments of the northern Arabian Gulf (e.g. Aqrawi & Sadooni, 1988). It is usually thought to have originated from the sediments and soils of the Mesopotamian flood plains introduced by northwesterly (Shamal) winds (e.g. A1-Bakri et al ., 1984).…
Modeling of Non-isothermal Film Blowing with Integral Constitutive Equations
Abstract Non-isothermal, melt film-blowing is analysed by means of a nonlinear integral constitutive equation that incorporates shear history effects, spectrum of relaxation times, shear thinning and extension thinning or thickening. The temperature history, as predicted by the simultaneously solved energy equation, i…
Dubinin's Theory for the Volume Filling of Micropores: An Historical Approach
The origin and development of Dubinin's theory are presented within their historical context. The emphasis is put on the author's long-standing collaboration with M.M. Dubinin. It is shown how the main correlations between the structural properties of active carbons and the parameters of the DR and DA equations have b…
Routine identification of aluminium hydroxide polymorphs with the laser Raman microprobe
Abstract The laser Raman microprobe spectrum of gibbsite displays four intense v (OH)- stretching bands at ~3365, 3435, 3525 and 3618 cm -1 , bayerite shows three near 3425, 3545 and 3564 cm -1 , nordstrandite has three near 3492, 3566 and 3623 cm -1 , and doyleite one broad band centred at -3545 cm -1 with sometimes…
Ligand conformational changes affecting 5T2 .fwdarw. 1A1 intersystem crossing in a ferrous complex
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLigand conformational changes affecting 5T2 .fwdarw. 1A1 intersystem crossing in a ferrous complexJames K. McCusker, Hans Toftlund, Arnold L. Rheingold, and David N. HendricksonCite this: J. Am. Chem. Soc. 1993, 115, 5, 1797–1804Publication Date (Print):March 1, 1993Publicat…
The effect of temperature on the swelling of montmorillonite
Abstract The effect of temperature on the swelling of clay was studied by determining (1) the relation between the interlayer spacing, λ , and the swelling pressure, Π , at different values of the temperature, T , using the method of Viani et al . (1983) as modified by Wu et al . (1989); (2) the relation between λ and…
Polymer chain rupture and the fracture behavior of glassy polystyrene
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolymer chain rupture and the fracture behavior of glassy polystyreneN. Mohammadi, A. Klein, and L. H. SperlingCite this: Macromolecules 1993, 26, 5, 1019–1026Publication Date (Print):March 1, 1993Publication History Published online1 May 2002Published inissue 1 March 1993ht…
The Modelling of Adsorption and Precipitation Scale Inhibitor Squeeze Treatments in North Sea Fields
This paper presents an analyste and design study of field scale inhibitor squeeze treatments. Simulators of varying levels of complexity have been used to model squeeze data from several wells in North Sea fields. The modelling has been carried out both for simple single sandbody squeezes and for inhibitor treatments…
Ship magnetizations modelling by the finite element method
In order to increase the stealth of ships, the magnetic anomalies they create are minimized by using deGaussing systems. To improve the deGaussing process, the French Navy has requested a numerical model of the magnetic anomalies created by ships. The authors present an overview of their work in the finite-element mod…
Yarn Twisting Dynamics
To describe the dynamic process of a yarn twisting system, two conditions, kinematic and kinetic, are usually required. In this paper, general equations of twisting dynamics are derived. When combined, these equations can represent the propagation of twist in a traveling yam, and their solutions can give interesting i…
Using porous silicon as a sacrificial layer
A thick sacrificial layer for applications in bulk and surface micromachining can be achieved with porous silicon. The technology of freestanding parts of polysilicon is described. The etching process and the use of different masking layers are investigated.
High‐Temperature X‐ray Study of the Cubic‐Tetragonal Diffusionless Phase Transition in the ZrO 2 ─ErO 1.5 System: I, Phase Change between Two Forms of a Tetragonal Phase, t′ ‐ZrO 2 and t″ ‐ZrO 2 , in the Compositionally Homogeneous 14 mol% ErO 1.5 ‐ZrO 2
The cubic‐tetragonal phase transition of 14 mol% ErO 1.5 ‐ZrO 2 was investigated through high‐temperature powder X‐ray diffraction. A new tetragonal form without tetragonality, t″ ‐ZrO 2 , was taken into consideration, although only two forms of t‐ and t′ ‐ZrO 2 have previously been distinguished. The metastable t″ ‐Z…
Mechanical Properties of Fabric Woven from Yarns Produced by Different Spinning Technologies: Yarn Failure in Woven Fabric
A study has been conducted on the mechanisms of in-situ tensile failure of staple yams during uniaxial tensioning, as in a conventional ravel strip test. The yarns were PET/cotton blends processed on ring, rotor, and airjet spinning systems, and then woven into plain or twill weave fabrics. Load-extension behaviors of…
Primary Structure, Partial Purification and Regulation of Key Enzymes of the Acetyl Cycle of Arginine Biosynthesis in Bacillus Stearothermophilus: Dual Function of Ornithine Acetyltransferase.
A 3.4 kb EcoRI fragment, cloned in E. coli, that carries part of a cluster of genes encoding arginine biosynthetic functions of the thermophilic bacterium Bacillus stearothermophilus, was sequenced on both strands. The sequence consists of a truncated argC gene, an argJ region encoding a polypeptide with both N-acetyl…
Ultisols of lowlandDipterocarpforest in East Kalimantan, Indonesia
Thirty five Typic Paleudults and Typic Hapludults under a Lowland Dipterocarp Forest were characterized for clay minerals, free oxides, cation exchange capacity, and exchangeable bases. Kaolinite was predominant in the soil clays followed by quartz, vermiculite and gibbsite and an accessory amount of illite, partially…
Mineralogical stabilization of high-magnesium calcite; geochemical evidence for intracrystal recrystallization within Holocene porcellaneous foraminifera
Abstract Mineralogical stabilization of porcellaneous foraminifera is known to consist of chemical change without textural alteration at any scale. However, the nature of the alteration process has not been fully reconciled. Porcellaneous foraminifera from the freshwater diagenetic zone of two small islands in the Sch…
Bending properties and transformation temperatures of heat treated Ni‐Ti alloy wire for orthodontic appliances
The effect of heat treatment temperature on bending properties and transformation temperatures of a Ni-Ti alloy wire, 1.0 mm in diameter, was investigated so that superelasticity could be used in orthodontic appliances needing shape memory processes. The heat treatment process was at 713 K for 1.8 ks and between 673 K…
Calcium-zinc and calcium-cadmium exchange in suspensions of various types of clays
Abstract Calcium-cadmium and calcium-zinc exchange equilibria were studied at 20°C and constant ionic strength (0·015) on four clay minerals, viz. montmorillonite, bentonite, illite and vermiculite. Vermiculite and, to a lesser extent, illite and bentonite showed the strongest affinity for Cd 2+ or Zn 2+ over Ca 2+ io…