Materials Literature
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Modern scanning electron microscopy yields structural information down to 2 to 5 nm from thin, beam transparent biological specimens. This paper examines the possibilities of garnering this level of structural information from bulk, frozen-hydrated samples. Freeze-fractured, frozen-hydrated yeast cells, frequently tak…
Abstract Due to the ever growing and more complex demands on the properties of polymer materials, raw material producers and plastic processing industries are more and more interested in the continuous synthesis and modification of polymers. In this article the production of polystyrene and styrene–isoprene copolymers…
Abstract We have investigated the effect of added Si0 2 on the photochemistry of anthracene, 1, in cyclohexane. Adsorption of 1 onto the Si0 2 surface from cyclohexane follows a Freundlich adsorption isotherm indicating interactions between 1 and the surface over a distribution of adsorption sites. In the absence of o…
Up-conversion emission spectra of fluorophosphate glasses doped with Tm3+ and co-doped with Tm3+ and Yb3+ ions were obtained under two different excitation wavelengths (657 and 683 nm). Both samples show a stronger emission centered at 450 nm than the ones centered at 478 and 363 nm when 3F2 level of Tm3+ is excited a…
Abstract The electrochemical oxidation of anodic cobalt, nickel, and zinc in acetonitrile containing both 2‐pyrrole‐[N‐( o ‐hydroxyphenyl)methylimines] (H 2 L) and a bidentate ligand (1, 10‐phenanthroline(phen) or 2,2′‐bipyridine(bipy)) yielded compounds of general formula M(HL) 2 · phen and M(HL) 2 · bipy (M = Co, Ni…
Phase equilibria in the system ZrO 2 ─InO 1.5 have been investigated in the temperature range from 800° to 1700°C Up to 4 mol%, InO 1.5 is soluble in t ‐ZrO 2 at 1500°C. The martensitic transformation temperature m → t of ZrO 2 containing InO 1.5 is compared with that of ZrO 2 solid solutions with various other trival…
Abstract The interest for star‐shaped polymers arises from their unique structure and enhanced segment density. This paper will review the different methods of preparation for star‐shaped polymers. Two cases of special interest will be considered in greater detail: the core‐first method which gives access to end‐funct…
Two ultra-high-temperature materials, hafnium carbide and hafnium diboride, were oxidized in the temperature range 1400 to 2100 C. The two materials oxidized in distinctly different ways. The carbide formed a three-layer system consisting of a layer of residual carbide, a layer of reduced (partially oxidized) hafnium…
The local structure of a Na 2 O─SiO 2 oxide glass and a Na 2 O─iO 2 ─Si 3 N 4 oxynitride glass has been investigated by the pulsed neutron diffraction method. In the oxide glass, the first peak of radial distribution function (RDF) curves appeared at 0.1627 nm corresponding to Si─O boxh length. In the oxynitride glass…
Abstract The permeation and separation characteristics of poly(vinyl chloride) (PVC) and poly[(vinyl chloride)‐ co ‐(vinyl acetate)] (poly(VC‐ co ‐VAc)) membranes were investigated for aqueous organic acid solutions by pervaporation and evapomeation. The PVC membrane preferentially incorporates organic acids and predo…
Abstract Cyclopentanone condensed with phenylhydrazones 5 , or oximes 6 , in the presence of zinc dust, sodium propionate and propionic acid at 150° to give cyclopenta[ b ]pyrroles 7 in good yields. This chemistry was extended to the synthesis of pyrrolic products from 1‐indanone, 2‐indanone and 2‐methylcyclopentanone…
A computation of power transformer parameters with a numerical method using finite elements is presented. The modeling, based on the calculation of the 3-D electromagnetic field, allows a novel approach to the study of the high-frequency phenomena that propagate along the transformer windings. These parameters include…
Increased likelihood of armed forces operations occurring in hostile climatic regions have increased the need for highly specialized protective clothing systems. Protection is needed under a variety of conditions which often present conflicting requirements. Protective military clothing provides broad design possibili…
Abstract Pipes of isotactic polybutene‐1 (PB) have been exposed to internal water and external air in pressure tests at 105°C. The pipes exposed to different internal pressures exhibited different failure mechanisms, referred to as stages I, II, and III. Samples taken from these pipes have been analyzed by infrared (I…
The authors discuss the 3-D electromagnetic modeling of a transformer to evaluate eddy current losses in the tank. To achieve this, several numerical methods are used with two 3-D field computation packages. Conventional volume elements and shell elements are used for the modeling of thin conducting regions. Surface e…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInclusion compound formed between poly(.epsilon.-caprolactone) and ureaChristy Choi, D. D. Davis, and A. E. TonelliCite this: Macromolecules 1993, 26, 6, 1468–1470Publication Date (Print):March 1, 1993Publication History Published online1 May 2002Published inissue 1 March 19…
<div class="htmlview paragraph">The development of commercial magnesium die casting alloys has progressed over the past several decades. The most common die casting alloy, AZ91D with 9% aluminum content, has been and still is used in many structural automotive applications.</div> <div class="htmlview pa…
DSC and TGA studies were made of jute fibers treated with a flame retardant formulation, borax-formaldehyde-sodium hydrosulphite. DSC thermograms were ob tained in both nitrogen and air atmospheres and TGA thermograms in nitrogen at mosphere. A thermal analysis was also made of fibers treated with borax alone. A compa…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReaction of platinum-gold cluster compounds with dihydrogenT. G. M. M. Kappen, J. J. Bour, P. P. J. Schlebos, A. M. Roelofsen, J. G. M. Van der Linden, J. J. Steggerda, Mark A. Aubart, Donald A. Krogstad, Marcel F. J. Schoondergang, and Louis H. PignoletCite this: Inorg. Che…
Although abrasion-resistant high-chromium cast irons are difficult to machine due to their high hardness and eutectic carbide content, this problem can be reduced by the use of annealing treatments to soften the matrix structures. After machining, the irons can then be hardened by destabilisation, air cooling and temp…