Materials Literature
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We study a system of hard spherocylinders with rotational freedom in which the length-to-diameter ratio of the spherocylinder L/D is large. The asymptotic expressions for the one-particle distribution function and the free-energy functional in the limit L/D\ensuremath{\rightarrow}\ensuremath{\infty} are found. The vir…
The artificial photosynthesis of ammonia , that is, the fixation of N 2 and conversion to NH 3 , is a fascinating research goal about which there are repeated reports of success in the literature. This communication now shows amongst other results why the obvious methods, in particular the heterogeneous catalysis of t…
The morphological change of natural pores with densification was examined in an alumina green body. The liquid‐immersion technique was used for observing pores inside the body before and after sintering. In this technique the specimen is made transparent by an adequate immersion liquid and observed with a transmission…
Abstract The clay-polysaccharide interaction is of practical importance in the formation and stabilization of soil aggregates. This study examined the adsorption of three synthetic polysaccharides (PSS) and one soil PSS on Silver Hill illite. The adsorption of PSS was influenced by both the adsorbed cations on the ads…
We measured the Raman spectrum associated with the transverse optical (TO) phonon of cubic SiC (β-SiC) whiskers as a function of stress using a diamond anvil cell (for hydrostatic stress, X) and an individual whisker microtension apparatus (for uniaxial stress along [111], P). These experiments were used to calibrate…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAnionic polymerization of lactones. 14. Anionic block copolymerization of δ-valerolactone and L-lactide initiated with potassium methoxidePiotr Kurcok, Jan Penczek, Jan Franek, and Zbigniew JedlinskiCite this: Macromolecules 1992, 25, 9, 2285–2289Publication Date (Print):Apr…
A ruling engine for large and/or high-groove density gratings is developed. A hybrid driving method that uses a piezoelectric device and a screw-nut mechanism is adopted to achieve stop-and-go blank motion with a closed-loop control system. Several test gratings, including a ruled area of 300(width) x 200(groove lengt…
The compressional mechanism of a random fiber assembly is analyzed by an energy method. An infinitesimal fiber segment, which is bounded by two neighboring contact points, is chosen as the unit bending element. The geometry of this element is characterized by its arc length, curvature, and orientation. The change in b…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNature of the manganese(I)-dioxolene bonding as a function of the ligand oxidation state: UV-visible, IR, and resonance Raman spectroelectrochemical study of [Mn(CO)3Ln(Diox)]z (n = 0, 1; z = -2, -1, 0, +1) and [Mn(CO)2{P(OEt)3}m(Diox)]z (m = 1, 2; z = -1, 0, +1) complexesFr…
Transparent glasses with densities greater than 8 g/mL, which are resistant to nuclear radiation damage and can serve as a host for rare‐earth scintillators, are being developed. Glasses in the PbO–Bi 2 O 3 system are known to have some of the highest densities yet reported. In this study, a thorough reexamination of…
Dynamic water vapor and heat transport in the transient state was investigated for fabrics made of polyester, acrylic, cotton, and wool fibers. The overall dissipation rate of water vapor depends on both the vapor transport rate and the vapor absorption by fibers, which are mutually interrelated. Water vapor transport…
A standard model of glasses is shown to exhibit unexpected and remarkably simple elastic properties. For a sequence of networks of decreasing degree or coordination z, the number of zero-frequency vibrational modes (also called ``degrees of freedom'') increases as ${\mathit{e}}^{\mathrm{\ensuremath{-}}\mathit{z}/\math…
Boron carbide–boron nitride particulate composites were fabricated by vacuum hot‐pressing. Near‐theoretical densities of B 4 C were obtained, but percent theoretical densities decreased with increasing amounts of BN. The grain size of B 4 C and BN was not affected by composition, but the amount of twinning in B 4 C de…
A SiO 2 ─Al 2 O 3 ─CaO─CaF 2 ionomer glass was investigated using thermal analysis, X‐ray diffraction, and scanning electron microscopy. The purpose of this investigation was to control the susceptibility of the glass to acid attack. The differential thermal analysis trace exhibited a sharp glass transition at about 6…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSurface-enhanced Raman scattering of the acid-base forms of imidazole on silverDavid A. Carter and Jeanne E. PembertonCite this: Langmuir 1992, 8, 4, 1218–1225Publication Date (Print):April 1, 1992Publication History Published online1 May 2002Published inissue 1 April 1992ht…
We report a simple and quick synthesis of tetrapyrrolic macrocycle in dry media conditions, under microwave irradiation. Heating in microwave oven pyrrole and benzaldehyde adsorbed on a solid acidic support affords tetraphenylporphyrin within ten minutes with very simplified treatment and purification.
An experimental technique for measuring the time-varying response of an oscillating, acoustically levitated air bubble in water is developed. The bubble is levitated in a resonant cell driven in the (r,θ,z) mode of (1,0,1) at a frequency fd≊24 kHz. Linearly polarized laser light (Ar–I 488.0 nm) is scattered from the b…
The objectives of this study were to examine (1) interrelationships between various forms of extractable A1 and selected soil properties, (2) the contribution of extractable A1 to pH buffer capacity, and (3) investigate the use of extractable A1 to predict lime requirement. Aluminium was extracted from each of 60 Quee…
Abstract Blends of an aromatic polyethersulfone (commercial name Victrex) and a polyimide (commercial name Matrimid 5218), the condensation product of 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride and 5(6)‐amino‐1‐(4′‐aminophenyl)‐1,3,3′‐trimethylindane, were studied by differential scanning calorimetry, dynamic…
Low-energy electron diffraction (LEED) is a well established technique for evaluation of the surface atom arrangement. The information is derived from the elastically scattered electrons. Usually the thermal diffuse background between diffraction spots is assumed to be constant and subtracted as a constant. For spot p…