1,134 research outputs found
Giant phase-conjugate reflection with a normal mirror in front of an optical phase-conjugator
We theoretically study reflection of light by a phase-conjugating mirror
preceded by a partially reflecting normal mirror. The presence of a suitably
chosen normal mirror in front of the phase conjugator is found to greatly
enhance the total phase-conjugate reflected power, even up to an order of
magnitude. Required conditions are that the phase-conjugating mirror itself
amplifies upon reflection and that constructive interference of light in the
region between the mirrors takes place. We show that the phase-conjugate
reflected power then exhibits a maximum as a function of the transmittance of
the normal mirror.Comment: 8 pages, 3 figures, RevTe
Giant magnetoresistance in Co/Cu multilayers sputtered with Kr
This paper presents some results of magnetoresistance measurements on Kr-sputter-deposited Co/Cu multilayers. We find that Co/Cu MLs sputtered with Kr gas show a larger GMR effect than those sputtered with Ar gas
Resistivity due to low-symmetrical defects in metals
The impurity resistivity, also known as the residual resistivity, is
calculated ab initio using multiple-scattering theory. The mean-free path is
calculated by solving the Boltzmann equation iteratively. The resistivity due
to low-symmetrical defects, such as an impurity-vacancy pair, is calculated for
the FCC host metals Al and Ag and the BCC transition metal V. Commonly, 1/f
noise is attributed to the motion of such defects in a diffusion process.Comment: 24 pages in REVTEX-preprint format, 10 Postscript figures. Phys. Rev.
B, vol. 57 (1998), accepted for publicatio
About the screening of the charge of a proton migrating in a metal
The amount of screening of a proton in a metal, migrating under the influence
of an applied electric field, is calculated using different theoretical
formulations. First the lowest order screening expression derived by Sham
(1975) is evaluated. In addition 'exact' expressions are evaluated which were
derived according to different approaches. For a proton in a metal modeled as a
jellium the screening appears to be 15 +/- 10 %, which is neither negligible
not reconcilable with the controversial full-screening point of view of
Bosvieux and Friedel (1962). In reconsidering the theory of electromigration, a
new simplified linear-response expression for the driving force is shown to
lead to essentially the same result as found by Sorbello (1985), who has used a
rather complicated technique. The expressions allow for a reduction such that
only the scattering phase shifts of the migrating impurity are required.
Finally it is shown that the starting formula for the driving force of Bosvieux
and Friedel leads exactly to the zero-temperature limit of well-established
linear response descriptions, by which the sting of the controversy has been
removed.Comment: 14 pages, 5 figure
Mouse Models in Arrhythmogenic Right Ventricular Cardiomyopathy
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heart muscle disorder characterized by fibro-fatty replacement of cardiomyocytes. The cardinal manifestations are arrhythmias, sudden cardiac death, and seldom heart failure. Mutations in genes encoding desmosomal proteins and their interaction partners have been implicated in the pathogenesis of ARVC and it is now widely accepted that ARVC is a disease caused by abnormal cell–cell adhesion. The mechanism(s) by which mutations in desmosomal proteins lead to fibro-fatty replacement remains to be fully elucidated. To this aim over the last 10 years different transgenic and targeted mouse models have been developed, these models and what they have taught us will be discussed in this review
Superluminal Optical Phase Conjugation: Pulse Reshaping and Instability
We theoretically investigate the response of optical phase conjugators to
incident probe pulses. In the stable (sub-threshold) operating regime of an
optical phase conjugator it is possible to transmit probe pulses with a
superluminally advanced peak, whereas conjugate reflection is always
subluminal. In the unstable (above-threshold) regime, superluminal response
occurs both in reflection and in transmission, at times preceding the onset of
exponential growth due to the instability.Comment: 9 pages, 6 figures, RevTex, to appear in Phys. Rev.
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