Materials Literature
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The accumulation of 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) in rat brain has been examined after probenecid infusion over 8 h. At plasma probenecid concentrations of 200-400 micrograms mL-1 a steady state level in the accumulation of 5-HIAA and HVA was achieved, the increase above the endogenou…
Abstract A new crystalline compound has been synthesized by trimethylsilylation of tetraethylammonium silicate which was identified by means of gas chromatography, mass spectrometry, 29 Si NMR and X‐ray analysis to be a eage‐like double three‐ring silicic acid trimethylsilyl ester containing six inequivalent SiO 4 tet…
When developing new non-oriented electrical steels and assessing their performance in electrical machines their properties when magnetised under nonsinusoidal flux conditions must be considered. Several methods of approach have been attempted in the past but in this paper the performance of single strips has been exam…
Fine iron particles having coercivity higher than 2000 Oe were produced by the conventional method which is conmercially used,i.e, the reduction of acicular goethite particles with hydrogen gas. This could be done by adsorption of Nd3+or Ce3+ions together with B3+ions on the surface of the goethite particles. Electron…
Abstract The mechanical properties of polyurethane‐unsaturated polyester interpenetrating polymer networks (IPNs) that were prepared by reaction injection molding (RIM) process were measured with variations In composition, cross‐link density, and relative reaction rate. From dynamic mechanical analysis (DMA), it was f…
Present works describe the developments of the equiaxed Fe-Cr-Co permanent magnets with high coercivity and high energy products. The studied alloy compositions are Fe-(26-32)wt%Cr-15wt%Co-3wt%Mo. The magnetic properties of the alloys have been enhanced by the two-step thermomagnetic treatment (two-step TMT) and by pr…
Abstract Surface‐enhanced Raman scattering (SERS) has been observed for poly(4‐vinyl pyridine) absorbed onto silver island films. Bands near 1219 and 1613 cm −1 , which are weak in normal Raman spectra of PVP, are strong in SERS spectra, and the band near 1020 cm −1 , which is the strongest band in the normal spectra,…
With the increasing use of charge-coupled devices for astronomical observations, it is vital to obtain the highest quantum efficiency possible due to the limited amount of observing time available on large telescopes. One method of increasing the response of back-illuminated CCDs is to apply antireflection coatings. B…
There is an increasing need for new materials and methods for rapid but durable repair of concrete pavements where the closure time is in hours rather than days. The author outlines the main properties and reports on some aspects of durability derived from laboratory investigation and field experience. Magnesia phosph…
Abstract Thin films (45 – 1200 nm thickness) of polymeric phthalocyanines were prepared by the reaction of copper films on various carriers with gaseous aromatic tetracarbonitriles. The films were characterized by IR, UV/VIS, and ESCA spectra. The electrical conductivity is in the order of 10 −2 ‐10 −5 S cm −1 . The e…
Abstract Poly(2,6‐dimethyl‐1,4‐phenylene oxide) has been crosslinked in the presence of large poly(dimethylsiloxane) cyclics (92 repeating units). Approximately 26% by weight of the cyclics were threaded and permanently captured by the polymer network forming a topological isomeric structure referred to as a polymeric…
Measurements of Curie temperature, magnetic moment and magnetostriction were made on Tb.3Dy.7(Fe1-xTx)1.9where T = Co and Ni (0 \leq x \leq 1for Co and0 \leq x \leq .08for Ni). Alloys were prepared using a float zone technique, from which it was possible to grow oriented [112] crystallite samples for0 \leq x \leq .21(…
This study is the first to report on the use of x-ray photoelectron spectroscopy (XPS or ESCA) for studying the surface films (less than 10 nm thick) of aged amalgams. The concentrations and electron binding energies of the elements on the surfaces of four different amalgams aged for 20 min, one day, seven days, and 3…
2,3-Dihydroporphycene 1 and 2,3-dihydroporphyrin are constitutional isomers with similar bonding behavior and similar π-electron structure. 2,3-Dihydroporphyrin is of interest, inter alia, as parent compound of chlorophyll; 1 can be obtained by hydrogenation of porphycene.
Two examples of a new class of discotic liquid crystals are presented. Their molecular architecture consists of a trisubstituted central core (either a benzene or a cyclohexane ring) and three regional cores, with three decyloxy-chains in the 3,4,5-positions of a particular benzene ring. These regional cores are linke…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThin boundary layers of the melt of a biphenyl single crystal and its premeltingA. A. Chernov and V. A. YakovlevCite this: Langmuir 1987, 3, 5, 635–640Publication Date (Print):September 1, 1987Publication History Published online1 May 2002Published inissue 1 September 1987ht…
Abstract The transesterification reaction of molten ethylene and vinyl alcohol copolymers (EVA), in presence of paraffinic alcohols and basic catalysts, leads to high conversion of the ester groups to secondary alcohol in both discontinuous and continuous processing equipment. Various kinds of alcohols and two differe…
Histidine decarboxylases from Klebsiella planticola and Enterobacter aerogenes were purified to homogeneity and compared with the histidine decarboxylase from Morganella morganii. All three enzymes required pyridoxal 5'-phosphate as a coenzyme, showed optimal activity at pH 6.5, decarboxylated only histidine among the…
Quantitative analysis of siliceous microfossils preserved in a radiometrically dated core from the central basin of Lake Erie (North America) shows several distinct periods in the lake's response to anthropogenic effects. Prior to European settlement of the region, microfossil deposition rates were low, and the flora…
A Ca2+/calmodulin-dependent kinase has been purified which catalyzed the phosphorylation and concomitant inactivation of both the microsomal native (100,000 Da) and protease-cleaved purified 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase) (53,000 Da) fragments. This low molecular weight brain cytos…