556 research outputs found
Highly sensitive frequency metrology for optical anisotropy measurements
In this paper we present a novel apparatus aimed at measuring very small
birefringences and anisotropies, based on frequency metrology and not on
polarimetry as usual. In our experiment, a very high finesse resonant cavity is
used to convert the phase difference into a resonance frequency difference,
which can then be measured with very high accuracy. We describe the set-up and
present the results of experimental tests which exhibited a sensitivity dn ~ 2
x 10?18, allowing for the measurement of long-predicted magneto-electro-optical
effects in gases. Since the shotnoise limited sensitivity of our apparatus lies
well below the state-of-the-art sensitivity, frequency metrology appears as a
promising technique for small birefringence measurements.Comment: Accepted for publication in Review of Scientific Instrument
Arterial anatomy and arteriographic diagnosis of arteriogenic impotence
One hundred twenty-six bilateral selective arteriographic examinations of the iliopudendal vascular tree were performed after comprehensive multidisciplinary evaluation in patients with chronic erectile dysfunction. Best imaging results were obtained by performing the arteriography under epidural anesthesia after intracavernous injection of a vasoactive drug combination. The arteriography is mandatory prior to revascularization procedures. It is further indicated in primary erectile dysfunction and posttraumatic erectile failure. The importance of cavernosography and selective arteriography in primary erectile dysfunction is stressed. Increasing knowledge about the influence of vasoactive drugs on penile hemodynamics has led to its application in diagnosis and therapy of erectile dysfunction. Pharmacocovernosography, Doppler-ultrasound of penile arteries after intracavernous injection of a vasoactive drug combination, and pharmacoarteriography are refined techniques to prove a vascular etiology of erectile dysfunction. The results of the morphologic studies of the vascular system are correlated with functional testing of erectile capacity by intracavernous application of a papaverinephentolamine drug combination
Single grain heating due to inelastic cotunneling
We study heating effects of a single metallic quantum dot weakly coupled to
two leads. The dominant mechanism for heating at low temperatures is due to
inelastic electron cotunneling processes. We calculate the grain temperature
profile as a function of grain parameters, bias voltage, and time and show that
for nanoscale size grains the heating effects are pronounced and easily
measurable in experiments.Comment: 4 pages, 3 figures, revtex4, extended and corrected versio
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