Materials Literature
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Electrical resistivity and Hall effect coefficient measurements have been made on MnSi 1.73 thin films in the temperature range 100 to 850 K. The temperature dependence of resistivity shows the typical behaviour of a degenerate semiconductor. The energy gap calculated from resistivity and Hall effect data is about 0.4…
We present neutron-spin-echo results on the dynamics of crosslinks in a tetrafunctional model network of polydimethylsiloxane. The diffusive motion was found to be rouse type and restricted in space. For the first time the extent of these spatial limitations was determined experimentally. The results strongly support…
We have been able to observe the enhanced Raman scattering from copper phthalocyanine molecules deposited on layers of gas-evaporated GaP small particles. It is found that the enhancement factor increases as the average particle size increases; a maximum enhancement factor obtained in the size range between 400 and 11…
The one-dimensional, discrete Schr\"odinger equation is studied when the potential is allowed to take on two values, ${V}_{A}$ and ${V}_{B}$, which are arranged according to a generalized Fibonacci sequence. The problem is reduced to a dynamical map for the traces of the transfer matrices which are given recursively b…
This article presents a variational approach for calculation of the dynamic third-order susceptibility χ(3). The susceptibility is obtained directly through a solution of two sets of inhomogeneous linear equations.
Photoluminescence in the GR1 zero-phonon region has been examined in detail, using a tunable dye laser resonant with the higher excited states GR2 to GR8. The authors conclude that the temperature-dependent structure observed when electron beam excitation is used is not due to perturbation of the centre resulting from…
The Raman spectra of single-crystal Co 3 O 4 have been measured at 312 K. Five Raman-active modes were found and identified at 194, 482, 522, 618 and 691 cm -1 .
The loss of the antioxidants BHA and BHT from HDPE film was measured experimentally and analyzed theoretically. The volatilization of the antioxidant from the polymer surface was found to be the controlling parameter for mass transfer. Diffusion coefficients of the antioxidants evaluated from the experimental data and…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTwo components of an extracellular protein aggregate of Clostridium thermocellum together degrade crystalline celluloseJ. H. David Wu, William H. Orme-Johnson, and Arnold L. DemainCite this: Biochemistry 1988, 27, 5, 1703–1709Publication Date (Print):March 8, 1988Publication…
The influence of aspartate-168 on the proton-donating and -accepting properties of histidine-195 (the active site acid/base catalyst in lactate dehydrogenase) was evaluated by use of site-directed mutagenesis to change the residue to asparagine and to alanine. Despite the fact that asparagine could form a hydrogen bon…
RESUMENDurante el verano de 1984 se colectaron siete muestras de sedimentos y lama sobrenadante de tres zonas, para analizar las asociaciones de diatomeas bentónicas en la Laguna Figueroa, BC, Mtico.Se identificaron un total de 67 taxa entre especiesy variedades.Se utilizó un tamaño de muestra de 300 individuos, los v…
Organomercury(II) complexes involving isoniacinamide(I) of the type. RHgCl(L)(II) [R = phenyl, o-, p-hydroxyphenyl ( o-, p-HOC 6 H 4 ) , p-acetoxyphenyl (p-AcOC 6 H 4 ), 2-furyl (2-C 4 H 3 O); L = isoniacinamide] have been synthesized and characterized. Conductance measurements indicate that the complexes are non-elec…
Abstract The optimal reaction conditions of the homogeneous quaternization of regenerated cellulose with 3‐chloro‐2‐hydroxypropyltrimethylammonium chloride in solutions of benzyltriethylammonium hydroxide are established. Content of 6% of regenerated cellulose with the DP 320 in 1.8 M solution of BTEA‐OH at the molar…
Structural adhesives used for space applications must be able to survive large tempera ture fluctuations while maintaining their mechanical strength. This paper describes a series of experiments performed to document property degradation of Hysol Corps EA 956 epoxy due to temperature extremes experienced in the orbita…
The measurement of spontaneous polarisation in ferroelectric smectic-C liquid crystals is discussed. The method employed is that of field reversal and a new approach is described for the background current to be subtracted electronically from the current during switching to derive the component due to the polarisation…
The high-temperature (to 150 C) electrochemical polarization behavior of steel in highly alkaline sulfide solutions containing 2.5 molal (m) NaOH + 0.5 m Na2S is described. Anodic polarization and cyclic voltammetry were used. The behavior has been interpreted with reference to calculated thermodynamic electrode poten…
The directions of the absorption, fluorescence and phosphorescence transition moments of dioxido-p-terphenyl are determined from measurements of the absorption and emission anisotropies as functions of the dichroic ratio in stretched PVA films.
A method is presented for modeling two-dimensional dipoles, quadrupoles, and other higher multipoles built using oriented permanent-magnet materials such as samarium cobalt. The technique uses a complex current doublet to model the magnetized material. This technique can be used in conjunction with an infinitely perme…
Dielectric and pyroelectric behaviour of phenanthrene single crystals between 20 and 90°C have been investigated. Sharp peaks of ε have been observed during first heating of the samples. The pyroelectric charge in b-direction has been detected without a biasing field. The most probable explanation of all data availabl…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMathematical and experimental foundations of linear polycondensation modeling. 1. Modeling and simulation of linear, irreversible polycondensationM. R. N. Costa and J. VillermauxCite this: Ind. Eng. Chem. Res. 1988, 27, 3, 421–429Publication Date (Print):March 1, 1988Publica…