Materials Literature
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An ionic charge transfer complex of dimethylamino nitronyl nitroxide (DMANN) was prepared by grinding with DDQ in the solid state. An electronic spectrum of the complex showed a broad band at 0.65 eV. The conductivity of the complex was σ ∼ 10−6 S-cm−1 at room temperature. The measurement of the magnetic susceptibilit…
The major objective of the present work is to design a high speed steel composition for tool casting. The effect of replacement of V and W by Nb as a modifier of the structure and properties of cast S 2-9-2 (AISI M7) high speed steel has been investigated with the aid of EDX and WDX attached to the scaning electron mi…
Fourier transform infrared (FT-IR) spectroscopy was used to study the photopolymerization of 4,4'-bis(acryloyl)biphenyl (BAB), dispersed in the liquid crystal (E7). The infrared absorbance of the carbon–carbon double bond of the acrylate group was monitored to follow the course of the polymerization and to determine t…
Several [5]helicene-containing polyimides have been synthesized by chemical and thermal transformation of the precursor polyimides having the tetrahydro[5]helicene unit. The illustrated diamines 4a and 4b were polymerized with two dianhydrides (6FDA and s-BPDA) to form high molecular weight polyimides 5a,b and 6a,b, c…
Abstract A series of 2,3‐ O ‐carboxymethylcelluloses (CMC's), which are regioselectively substituted at the C‐2 and C‐3 position, were prepared and their water solubility was examined. It was found that the lower limit for the degree of substitution (DS) value of water‐soluble 2,3‐ O ‐CMC is about 0.3. This value was…
Several recent experiments on glycerol and other supercooled liquids have suggested that dynamically heterogeneous domains in the liquid are responsible for the nonexponential structural relaxation dynamics observed near the glass transition. In addition, it appears that the exchange of domain types may occur much mor…
The a.c. electrical properties of graphitized carbon-black filled rubbers were investigated in the temperature range 25–85°C and in the frequency range 10–106 Hz. The volume fraction of the filler varied from 15 to 60%. The a.c. impedance was found to decrease dramatically with increasing filler content for volume fra…
We report crystal magnetic susceptibility results of two $S=1/2$ one-dimensional Heisenberg antiferromagnets, ${\mathrm{KFeS}}_{2}$ and ${\mathrm{CsFeS}}_{2}.$ Both compounds consist of $({\mathrm{FeS}}_{4}{)}_{n}$ chains with an average Fe-Fe distance of 2.7 \AA{}. In ${\mathrm{KFeS}}_{2},$ all intrachain Fe-Fe dista…
In 1994 EMPA published an extensive study on 36 rain jackets (ARES project [5]). Testing and evaluation have been concentrated on the points of emphasis physiology and weather protection. The study has been positively recognised internationally. Encouraged by this positive response EMPA decided to carry out a new inve…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSingle-Crystal Matrix Isolation of BiopolymersJean Chmielewski, Jerry J. Lewis, Scott Lovell, Reena Zutshi, Phil Savickas, Christine A. Mitchell, J. Anand Subramony, and Bart KahrView Author Information Department of Chemistry, Purdue University West Lafayette, Indiana…
Chemical composition of the aqueous solution within crevices on two different Ni-Cr-Mo-Fe alloys immersed in natural seawater was determined using a semiquantitative thin-layer chromatographic method. Active crevices were found to contain concentrated amounts of dissolved Ni2+, Cr3+, Mo3+, and Fe2+ ions. Propagation o…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTA High-Resolution Calorimetry Study of the Order−Disorder Transition in a Diblock Copolymer MeltV. P. Voronov, V. M. Buleiko, V. E. Podneks, I. W. Hamley, J. P. A. Fairclough, A. J. Ryan, S.-M. Mai, B.-X. Liao, and C. BoothView Author Information Oil and Gas Research Institute…
Changes in the active site of fumarase (yeast fumarase II) that occur when fumarate is converted to malate (E.F --> E.M) must be reversed for another cycle of reaction to take place. As shown here, recycling of the enzyme includes two proton transfers and one conformational change. These events, together with the M-of…
Metal-ceramic microstructures were formed in situ by the partial reduction (i.e. the reduction of only one of the metallic elements) of the spinel compound NiAl2O4. Depending on reduction conditions, these microstructures consist of Ni particles embedded in an α-Al2O3 or a multiphase matrix called ‘defect spinel’. The…
The differential scanning calorimetry (DSC) at different heating rates was used to gain some insight into the thermal stability and calorimetric behaviour of the three-component tellurite silver vanadate glasses of the (TeO2)50–(V2O5)50—x–(Ag2O)ii, where x = 20, 22.5, 25, 27.5 wt%. The glass transformation temperature…
A technique is discussed in this paper for evaluating the performance of IR emitters in heating and drying fabrics. The efficiency of IR heating depends on both the fabric spectral absorption characteristics and the spectral emission of the infrared source. An FTIR spectrometer with an integrating sphere is used to me…
Microstructural evolution of gas‐pressure‐sintered Si 3 N 4 with Yb 2 O 3 as a sintering aid was observed. Microstructures typical for in situ toughened Si 3 N 4 , i.e., large elongated grains randomly distributed in a fine matrix, were observed. However, the size of the elongated grains near the surface was much larg…
The goal of this paper is to emphasize the multidisciplinary character of molecular magnetism as a whole, and of our own activity in this field. For that, we have briefly described some of our results concerning the theoretical simulation of thermodynamical properties of molecular magnetic materials, the study of spin…
Phosphorylase b kinase (PbK) from skeletal muscle is a highly regulated oligomer consisting of four copies of four distinct subunits (alphabetagamma)delta4. The gamma subunit is catalytic, and the remaining subunits are regulatory. To characterize effector-induced changes in the quaternary structure of the enzyme, we…
It has been shown by experimental and theoretical studies that exchange interactions in non planar π systems are strongly dependent on the geometrical parameters characterizing the non planarity. A study of the exchange interaction in isolated nitroxide biradicals is presented for non planar paraphenylene bis nitroxid…