83,372 research outputs found
The prospect of detecting single-photon force effects in cavity optomechanics
Cavity optomechanical systems are approaching a strong-coupling regime where
the coherent dynamics of nanomechanical resonators can be manipulated and
controlled by optical fields at the single photon level. Here we propose an
interferometric scheme able to detect optomechanical coherent interaction at
the single-photon level which is experimentally feasible with state-of-the-art
devices.Comment: 8 pages, 2 figure
A co-operating solver approach to building simulation
This paper describes the co-operating solver approach to building simulation as encapsulated within the ESP-r system. Possible adaptations are then considered to accommodate new functional requirements
Some t-tests for N-of-1 trials with serial correlation
N-of-1 trials allow inference between two treatments given to a single
individual. Most often, clinical investigators analyze an individual's N-of-1
trial data with usual t-tests or simple nonparametric methods. These simple
methods do not account for serial correlation in repeated observations coming
from the individual. Existing methods accounting for serial correlation require
simulation, multiple N-of-1 trials, or both. Here, we develop t-tests that
account for serial correlation in a single individual. The development includes
effect size and precision calculations, both of which are useful for study
planning. We then evaluate and compare their Type I and II errors and interval
estimators to those of usual t-tests analogues via Monte Carlo simulation. The
serial t-tests clearly outperform the usual t-tests commonly used in reporting
N-of-1 results. Examples from N-of-1 clinical trials in fibromyalgia patients
and from a behavioral health setting exhibit how accounting for serial
correlation can change inferences. These t-tests are easily implemented and
more appropriate than simple methods commonly used; however, caution is needed
when analyzing only a few observations. Keywords: Autocorrelation; Cross-over
studies; Repeated measures analysis; Single-case experimental design;
Time-seriesComment: 23 pages, 6 figures, 6 table
Noise-assisted Mound Coarsening in Epitaxial Growth
We propose deposition noise to be an important factor in unstable epitaxial
growth of thin films. Our analysis yields a geometrical relation H=(RWL)^2
between the typical mound height W, mound size L, and the film thickness H.
Simulations of realistic systems show that the parameter R is a characteristic
of the growth conditions, and generally lies in the range 0.2-0.7. The
constancy of R in late-stage coarsening yields a scaling relation between the
coarsening exponent 1/z and the mound height exponent \beta which, in the case
of saturated mound slope, gives \beta = 1/z = 1/4.Comment: 4 pages, RevTex Macros, 3 eps figure
An observation of cosmic ray positrons from 10-20 GeV
A balloon flight of the University of Chicago electron telescope was performed. Making use of the east-west asymmetry in the geomagnetic cut off rigidity, the cosmic ray positrons and negatrons were separated over the range 10 GeV to 20 GeV. The positron to electron ratio, e+/(e++e-), was measured to be 17% + or - 5%, significantly higher than the ratio measured in the 1 GeV to 10 GeV range by other experiments. This increase appears to suggest that either a primary component of positrons become significant above 10 GeV, or that the spectrum of primary negatrons decreases above 10 GeV more sharply than that of secondary positrons
SIMULATION STUDY ON WATERFLOOD FRONT: BLOCK HADE OF TARIM OILFIELD IN NORTHWEST CHINA
Block Hade consist of a deep thin sandstone reservoir of two sub-layer reservoirs. The thickness is
about 1.5 m for each layer. The two-layer “staircase” horizontal well is used for recovery. In order
to determine water displacement front and edge water movement, tracer test is conducted in the
reservoir. But the cycle of field tracer monitoring is about 150-360 days. This prevented the efficient
monitoring of waterflood swept area and waterflood advance direction and velocity, after the cycle
of tracer monitoring. Conservation of mass with respect to tracer flow and history performance
matching of tracer enabled the study of water-flood front and edge-water advance. The simulation result
is basically consistent with the monitored field tracer results. Therefore, numerical model can be used to
conduct a longer monitoring period. It can make up for the disadvantage of the complexity of the
tracer monitoring setup, its implementation, and time-consuming monitoring cycle. The water-flood
front, water-flood swept area, advancing velocity and the predominant water injection direction can be
obtained. Furthermore, it is possible to evaluate and predict the injection-production well interaction and
can also provide a reliable basis to deploy reasonable flood patterns to enhance oil recovery
Momentum Resolution Improvement Technique for Silicon Tracking Detectors using dE/dx
A technique for improving the momentum resolution for low momentum charged
particles in few layer silicon based trackers is presented. The particle
momenta are determined from the measured Landau dE/dx distribution and the
Bethe-Bloch formula in the 1/beta^2 region. It is shown that a factor of two
improvement of the momentum determination is achieved as compared to standard
track fitting methods. This improvement is important in large scale heavy ion
experiments which cover the low transverse momentum spectra using stand-alone
silicon tracking devices with a few planes like the ones used in STAR at RHIC
and ALICE at LHC.Comment: 9 pages, 4 figures. Accepted for publication in NIM A 40956 (ref.
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