749 research outputs found
In situ determination of the energy dependence of the high-frequency mobility in polymers
The high-frequency mobility in disordered systems is governed by transport
properties on mesoscopic length scales, which makes it a sensitive probe for
the amount of local order. Here we present a method to measure the energy
dependence of the high frequency mobility by combining an electrochemically
gated transistor with in-situ quasi-optical measurements in the sub-terahertz
domain. We apply this method to
poly([2-methoxy-5-(3',7'-dimethylocyloxy)]-p-phenylene vinylene) (OC_1C_10-PPV)
and find a mobility at least as high as 0.1 cm^2V^-1s^-1.Comment: 3 pages (incl. 3 figures) in Appl. Phys. Let
Activation analysis of admixtures in certain semiconductive materials
The use of extractions and chromatographic operations to separate macrobases, and to divide elements into groups convenient for gamma-spectrometric analysis is discussed. Methods are described for the activation detection of some impurities in silicon, arsenic, thallium, and trichloromethylsilane, on the basis of the extraction properties of bis(2-chlorethyl ether) and dimethylbenzylalkylammonium chloride. A schematic diagram of the extraction separation of elements-admixture is presented showing the aqueous and organic phases. The content percentage of the various elements are given in tables
One-loop counterterms for the dimensional regularization of arbitrary Lagrangians
We present master formulas for the divergent part of the one-loop effective
action for an arbitrary (both minimal and nonminimal) operators of any order in
the 4-dimensional curved space. They can be considered as computer algorithms,
because the one-loop calculations are then reduced to the simplest algebraic
operations. Some test applications are considered by REDUCE analytical
calculation system.Comment: 39 pages, Latex, 3 PS figures, replaced with published versio
Glassy Dynamics Under Superhigh Pressure
Nearly all glass-forming liquids feature, along with the structural
alpha-relaxation process, a faster secondary process (beta-relaxation), whose
nature belongs to the great mysteries of glass physics. However, for some of
these liquids, no well-pronounced secondary relaxation is observed. A prominent
example is the archetypical glass-forming liquid glycerol. In the present work,
by performing dielectric spectroscopy under superhigh pressures up to 6 GPa, we
show that in glycerol a significant secondary relaxation peak appears in the
dielectric loss at P > 3 GPa. We identify this beta-relaxation to be of
Johari-Goldstein type and discuss its relation to the excess wing. We provide
evidence for a smooth but significant increase of glass-transition temperature
and fragility on increasing pressure.Comment: 5 pages, 5 figures, final version with minor changes according to
referee demands and corrected Figs 1 and
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