48,817 research outputs found
A Discrete Model for Histogram Shaping
The aim of this article is to present a discrete model for histogram shaping. This is
an important image transformation with several practical applications. The model that is proposed is based on a generalization of the inferior part function. Finally, an algorithm based on this model is developed
STS-3/OSS-1 Plasma Diagnostics Package (PDP) measurements of Orbiter transmitter and subsystem electromagnetic interference
The plasma diagnostics package receiver system is described to identify the various antennas and to characterize the complement of receivers which cover the frequency range of 30 Hz to 800 Hz and S-band at 2200 + or - 300 MHz. Sample results are presented to show the variability of electromagnetic effects associated with the orbiter and the time variability of these effects. The electric field and magnetic field maximum and minimum field strength spectra observed during the mission at the pallet location are plotted. Values are also derived for the maximum UHF transmitter and S-band transmitter field strengths. Calibration data to convert from the survey plots to actual narrowband and broadband field strengths are listed
STS-3/OSS-1 Plasma Diagnostics Package (PDP) measurements of the temperature pressure and plasma
Designed to withstand the thermal extremes of the STS-3 mission through the use of heaters and thermal blankets, the plasma diagnostics package sat on the release/engagement mechanism on the OSS-1 payload pallet without a coldplate and was attached to the RMS for two extended periods. Plots show temperature versus mission elapsed time for two temperature sensors. Pressure in the range of 10 to the -3 power torr and 10 to the -7 power torr, measured 3 inches from the skin of the package is plotted against GMT during the mission. The most distinctive feature of the pressure profile is the modulation at the obit period. It was found that pressure peaks when the atmospheric gas is rammed into the cargo bay. Electric and magnetic noise spectra and time variability due to orbiter systems, UHF and S-band transmitter field strengths, and measurements of the ion spectra obtained both in the cargo bay and during experiments are plotted
Head impact exposure in junior and adult Australian football players
Tis study measured and compared the frequency, magnitude, and distribution of head impacts sustained by junior and adult Australian football players, respectively, and between player positions over a season of games. Twelve junior and twelve adult players were tracked using a skin-mounted impact sensor. Head impact exposure, including frequency, magnitude, and location of impacts, was quantifed using previously established methods. Over the collection period, there were no signifcant diferences in the impact frequency between junior and adult players. However, there was a signifcant increase in the frequency of head impacts for midfelders in both grades once we accounted for player position. A comparable amount of head impacts in both junior and adult players has implications for Australian football regarding player safety and medical coverage as younger players sustained similar impact levels as adult players. Te other implication of a higher impact profle within midfelders is that, by targeting education and prevention strategies, a decrease in the incidence of sports-related concussion may result
Electron and ion density depletions measured in the STS-3 orbiter wake
The third Space Shuttle flight on Columbia carried instrumentation to measure thermal plasma density and temperature. Two separate investigations, the Plasma Diagnostics Package (PDP) and the Vehicle Charging and Potential Experiment (VCAP), carried a Langmuir Probe, and the VCAP also included a Spherical Retarding Potential Analyzer (SRPA). Only those measurements made while the PDP is in the payload bay are discussed here since the VCAP instrumentation remains in the payload bay at all times and the two measurements are compared. The wake behind a large structure (in this case the Space Shuttle Orbiter) flying through the ionospheric plasma is discussed. Much theoretical work was done regarding plasma wakes. The instrumentation on this mission gives the first data taken with a large vehicle in the ionospheric laboratory. First, the PDP Langmuir Probe and its data set will be presented, then the VCAP Langmuir Probe and SRPA with associated data. The agreement between the two data sets is discussed and then followed by some other PDP data which infers an even lower wake density
Boson Pairs in a One-dimensional Split Trap
We describe the properties of a pair of ultracold bosonic atoms in a
one-dimensional harmonic trapping potential with a tunable zero-ranged barrier
at the trap centre. The full characterisation of the ground state is done by
calculating the reduced single-particle density, the momentum distribution and
the two-particle entanglement. We derive several analytical expressions in the
limit of infinite repulsion (Tonks-Girardeau limit) and extend the treatment to
finite interparticle interactions by numerical solution. As pair interactions
in double wells form a fundamental building block for many-body systems in
periodic potentials, our results have implications for a wide range of
problems.Comment: 9 pages, 8 figure
Quantum Chessboards in the Deuterium Molecular Ion
We present a new algorithm for vibrational control in deuterium molecules
that is feasible with current experimental technology. A pump mechanism is used
to create a coherent superposition of the D2+ vibrations. A short, intense
infrared control pulse is applied after a chosen delay time to create selective
interferences. A `chessboard' pattern of states can be realized in which a set
of even- or odd-numbered vibrational states can be selectively annihilated or
enhanced. A technique is proposed for experimental realization and observation
of this effect using 5 fs pulses of 790 nm radiation, with intermediate
intensity (5e13 W/cm2)Comment: 12 pages, 5 figure
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