Materials Literature
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Raman spectra of olivines along the forsterite-monticellite (Fo-Mo) join have been measured in the region of 100-1200 cm-' with a multichannel micro-Raman spectrometer. In the spectrum of Fo, strong Si-Osymmetric stretching bands appear at 824 and at 855 cm-r, and a medium-intensity antisymmetric Si-O stretching band…
Two microscopic methods for characterizing the maturity of a cotton sample have been developed, using either cross-sectional or longitudinal scanning of fibers by image analysis. This study compares the two methods for consistency with the aim of opti mizing their efficiency and accuracy as reference methods. Longitud…
The grain size‐microcracking relation was examined for low thermal expansion NaZr 2 (PO 4 ) 3 family ceramics. By measurements of the strength, Young's modulus, thermal expansion, and grain size of polycrystalline ceramics sintered at appropriate conditions, the critical grain size for microcracking was determined. Th…
X-ray-diffraction studies carried out on Tb0.27Dy0.73Fe2−xCox (x=0,0.5,1.2,2.0) revealed that all compositions investigated retained the C-15 cubic Laves phase structure. Magnetization and electrical resistivity measurements were carried out in the temperature range 77–800 K. Anomalies observed in the resistivity meas…
The change in the visible spectra of some irradiated ternary borate glasses containing chromium has been studied by increasing the γ‐ray doses with changing alkali content or increasing chromium concentration. In the glass without chromium, the γ‐rays induce two absorption bands which are attributed to the formation o…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDependence of the transitional properties of polystyrene-based side-chain liquid-crystalline polymers on the chemical nature of the mesogenic groupC. T. Imrie, T. Schleeh, F. E. Karasz, and G. S. AttardCite this: Macromolecules 1993, 26, 3, 539–544Publication Date (Print):Fe…
Long‐range‐oriented liquid‐crystalline polymers (LCPs) can exhibit anisotropic mechanical, optical, electrical, and magnetic properties. The macroscopic orientation of LCPs proceeds relatively slowly and incompletely compared to low molecular weight liquid crystals. Here, the photopolymerization of thin films of nemat…
Small metal particles embedded in an optically transparent matrix result in a composite material which can be transparent in the infrared and into the visible (metals are usually optically opaque). The nanoparticles of the metal are produced by the “template” method, where the material is synthesized within the pores…
In this brief review, structure models (several proposed by others, and some of the author's) of decagonal aluminum-transition metal phases are presented in a uniform fashion a tiling decorations. I discuss the ways in which clusters may be placed on tilings, and the consequences for the space group. Finally, the mode…
Abstract Untersucht wurde der Einfluß fester NaCl‐Ablagerungen auf der Zunderschicht auf die Oxidation der technischen Stähle X10 CrMoV 12 1, X15 CrNiSi 20 12 und X10 CrNiSi 25 20 bei 700°C. Unabhängig von der Legierungszusammensetzung löste die Anwesenheit von NaCl(s) auf der Oberfläche voroxidierter Proben stark bes…
Abstract Li 5 B 7 S 13 (C2/c; a = 17,304(2) Å, b = 21,922(3) Å, c = 12,233(2) Å, β = 134,91(1)°; Z = 8 und Li 9 B 19 S 33 (C2/c; a = 23,669(9) Å, b = 14,361(3) Å, c = 12,237(3) Å, β = 103,77(2)°; Z = 4 wurden durch Reaktion von stöchiometrischen Mengen Lithiumsulfid, Bor und Schwefel bei 750°C (Li 5 B 7 S 13 ) und 700…
Abstract Ammonium-saponite is hydrothermally grown at temperatures below 300°C from a gel with an overall composition corresponding to (NH 4 ) 0.6 Mg 3 Si 3.4 Al 0.6 O 10 (OH) 2 . The synthetic saponite and coexisting fluid have been characterized by means of X-ray powder diffraction, X-ray fluorescence, Induced Coupl…
First examples of amphiphilic alkyl pentakis(phenylethynyl)benzene ethers containing functional groups at the terminal position of their alkoxy chains were synthesized by etherification of pentabromophenol with 11-bromoundecan-1-ol and 11-bromoundecanoic acid ethyl ester, respectively, and subsequent palladium catalyz…
To measure the pretilt angle in a liquid crystal cell, the crystal rotation method is commonly used because it is very precise and measurements can be obtained rapidly. However when a liquid crystal cell with insufficient uniformity of the cell gap is used, a significant error occurs due to a shift in the measurement…
Abstract Bioabsorbable composites were fabricated from poly(D, L‐lactide‐urethane) matrix reinforced with poly(glycolic acid) (DEXON) surgical mesh. The crosslinked polyurethane matrix was formed from the reaction of ethy1–2, 6‐diisocyanatohexanoate and poly (D, L‐lactide) triol, initiated from glycerol; the ultimate…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLiquid-crystalline order in mucusChristopher Viney, Anne E. Huber, and Pedro VerdugoCite this: Macromolecules 1993, 26, 4, 852–855Publication Date (Print):February 1, 1993Publication History Published online1 May 2002Published inissue 1 February 1993https://pubs.acs.org/doi/…
Transient charging currents in nematic liquid crystals have been measured with a single- and a double-voltage pulse technique to elucidate the role of impurity ions incorporated in the materials in the transient charging processes. In the single pulse experiment, a peak in the current transient is observed in the nema…
Polycrystalline samples of ${\mathrm{Sr}}_{\mathit{x}}$${\mathrm{NbO}}_{3}$ (0.75\ensuremath{\le}x\ensuremath{\le}0.90) have been successfully synthesized by a solid-state reaction technique using TiO as a reducing agent. Powder x-ray-diffraction analysis indicated that the samples with x\ensuremath{\ge}0.80 were sing…
An efficient bifunctional catalyst for the title reaction is cobalt tetra(hydroquinone)porphyrin 1. The oxidized form of 1 (shown right, R = hydroquinone) has one unit for the interaction with molecular O2, and another for the interaction with the Pd catalyst. Thus, electrons can be transferred rapidly from the Pd com…
It has been previously shown, by equilibrium denaturation, that human growth hormone (hGH) folds by a cooperative two-state process. This is in contrast to the folding pathways of other nonhuman growth hormones that contain stable monomeric and multimeric equilibrium intermediates. We have reinvestigated the equilibri…