3,873 research outputs found
Signal ratio system utilizing voltage controlled oscillators Patent
Voltage controlled oscillators and pulse amplitude modulation for signal ratio syste
An interferometer tracking radar system
Fine tuning acquisition and tracking interferometer radar system uses a first antenna array of at least three receiving antennas. Array includes a reference antenna, a coarse tuning antenna, and a fine tuning antenna aligned on a receiving axis. Short range rendezvous system provides increased position accuracy
Ni-cd Battery Life Expectancy in Geosynchronous Orbit
The feasibility of using nickel cadmium batteries as an alternate if flight qualified NiH2 batteries are not available is explored. Battery life expectancy data being a key element of power system design, an attempt is made to review the literature, life test data and in orbit performance data to develop an up to date estimate of life expectancy for NiCd batteries in a geosynchronous orbit
A system for early warning of bearing failure
System for detecting incipient failure in ball bearings is described. Ultrasonic equipment detects bearing system resonance and provides warning signal through electronic circuitry. Detector can be used to evaluate performance of newly installed bearings. Schematic diagram is provided to show components
Magneto-optical Kerr effect in
We have measured the magneto-optical Kerr rotation of ferromagnetic
with x=0.2 and 0.4, as well as of serving as
the non-magnetic reference material. As previously for , we could
identify a feature at 1 in the Kerr response which is related with
electronic transitions involving the localized 4f electron states. The absence
of this feature in the data for confirms the relevance of the
partially occupied 4f states in shaping the magneto-optical features of
-based hexaborides. Disorder by -doping broadens the itinerant charge
carrier contribution to the magneto-optical spectra
Inside the Bondi radius of M87
Chandra X-ray observations of the nearby brightest cluster galaxy M87 resolve
the hot gas structure across the Bondi accretion radius of the central
supermassive black hole, a measurement possible in only a handful of systems
but complicated by the bright nucleus and jet emission. By stacking only short
frame-time observations to limit pileup, and after subtracting the nuclear PSF,
we analysed the X-ray gas properties within the Bondi radius at 0.12-0.22 kpc
(1.5-2.8 arcsec), depending on the black hole mass. Within 2 kpc radius, we
detect two significant temperature components, which are consistent with
constant values of 2 keV and 0.9 keV down to 0.15 kpc radius. No evidence was
found for the expected temperature increase within ~0.25 kpc due to the
influence of the SMBH. Within the Bondi radius, the density profile is
consistent with . The lack of a temperature increase inside
the Bondi radius suggests that the hot gas structure is not dictated by the
SMBH's potential and, together with the shallow density profile, shows that the
classical Bondi rate may not reflect the accretion rate onto the SMBH. If this
density profile extends in towards the SMBH, the mass accretion rate onto the
SMBH could be at least two orders of magnitude less than the Bondi rate, which
agrees with Faraday rotation measurements for M87. We discuss the evidence for
outflow from the hot gas and the cold gas disk and for cold feedback, where gas
cooling rapidly from the hot atmosphere could feed the cirumnuclear disk and
fuel the SMBH. At 0.2 kpc radius, the cooler X-ray temperature component
represents ~20% of the total X-ray gas mass and, by losing angular momentum to
the hot gas component, could provide a fuel source of cold clouds within the
Bondi radius.Comment: 14 pages, 8 figures, accepted by MNRA
Observation of soliton explosions in a passively mode-locked fiber laser
Soliton explosions are among the most exotic dissipative phenomena studied in
mode-locked lasers. In this regime, a dissipative soliton circulating in the
laser cavity experiences an abrupt structural collapse, but within a few
roundtrips returns to its original quasi-stable state. In this work we report
on the first observation of such events in a fiber laser. Specifically, we
identify clear explosion signatures in measurements of shot-to-shot spectra of
an Yb-doped mode-locked fiber laser that is operating in a transition regime
between stable and noise-like emission. The comparatively long,
all-normal-dispersion cavity used in our experiments also permits direct
time-domain measurements, and we show that the explosions manifest themselves
as abrupt temporal shifts in the output pulse train. Our experimental results
are in good agreement with realistic numerical simulations based on an
iterative cavity map.Comment: 5 pages, 5 figures, submitte
State of the University Address, 2010
President John R. Broderick\u27s 2010 State of the University Address and Faculty Welcome
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