13,075 research outputs found
Handbook explaining the fundamentals of nuclear and atomic physics
Indoctrination document presents nuclear, reactor, and atomic physics in an easy, straightforward manner. The entire subject of nuclear physics including atomic structure ionization, isotopes, radioactivity, and reactor dynamics is discussed
TB24: The Caddisflies (Trichoptera) of Maine Excepting the Family Hydroptilidae
A survey of the Trichoptera taken from light trap collections made during July and August, 1959, form the basis of the present paper. A checklist of the family Hydroptilidae known from Maine has been published. The collections were made for the most part in the Boreal Region of Maine.https://digitalcommons.library.umaine.edu/aes_techbulletin/1163/thumbnail.jp
Temporal Ordering in Quantum Mechanics
We examine the measurability of the temporal ordering of two events, as well
as event coincidences. In classical mechanics, a measurement of the
order-of-arrival of two particles is shown to be equivalent to a measurement
involving only one particle (in higher dimensions). In quantum mechanics, we
find that diffraction effects introduce a minimum inaccuracy to which the
temporal order-of-arrival can be determined unambiguously. The minimum
inaccuracy of the measurement is given by dt=1/E where E is the total kinetic
energy of the two particles. Similar restrictions apply to the case of
coincidence measurements. We show that these limitations are much weaker than
limitations on measuring the time-of-arrival of a particle to a fixed location.Comment: New section added, arguing that order-of-arrival can be measured more
accurately than time-of-arrival. To appear in Journal of Physics
Bounded Model Checking of State-Space Digital Systems: The Impact of Finite Word-Length Effects on the Implementation of Fixed-Point Digital Controllers Based on State-Space Modeling
The extensive use of digital controllers demands a growing effort to prevent
design errors that appear due to finite-word length (FWL) effects. However,
there is still a gap, regarding verification tools and methodologies to check
implementation aspects of control systems. Thus, the present paper describes an
approach, which employs bounded model checking (BMC) techniques, to verify
fixed-point digital controllers represented by state-space equations. The
experimental results demonstrate the sensitivity of such systems to FWL effects
and the effectiveness of the proposed approach to detect them. To the best of
my knowledge, this is the first contribution tackling formal verification
through BMC of fixed-point state-space digital controllers.Comment: International Symposium on the Foundations of Software Engineering
201
Screening of charged spheroidal colloidal particles
We study the effective screened electrostatic potential created by a
spheroidal colloidal particle immersed in an electrolyte, within the mean field
approximation, using Poisson--Botzmann equation in its linear and nonlinear
forms, and also beyond the mean field by means of Monte Carlo computer
simulation. The anisotropic shape of the particle has a strong effect on the
screened potential, even at large distances (compared to the Debye length) from
it. To quantify this anisotropy effect, we focus our study on the dependence of
the potential on the position of the observation point with respect with the
orientation of the spheroidal particle. For several different boundary
conditions (constant potential, or constant surface charge) we find that, at
large distance, the potential is higher in the direction of the large axis of
the spheroidal particle
Investigations on T violation and CPT symmetry in the neutral kaon system -- a pedagogical approach --
During the recent years experiments with neutral kaons have yielded
remarkably sensitive results which are pertinent to such fundamental phenomena
as CPT invariance (protecting causality), time-reversal invariance violation,
coherence of wave functions, and entanglement of kaons in pair states. We
describe the phenomenological developments and the theoretical conclusions
drawn from the experimental material. An outlook to future experimentation is
indicated.Comment: 41 pages, 9 figures. See arXiv:hep-ph/0603075 for an enlarged versio
Ion Trap Mass Spectrometers for Identity, Abundance and Behavior of Volatiles on the Moon
NASA GSFC and The Open University (UK) are collaborating to deploy an Ion Trap Mass Spectrometer on the Moon to investigate the lunar water cycle. The ITMS is flight-proven throughthe Rosetta Philae comet lander mission. It is also being developed under ESA funding to analyse samples drilled from beneath the lunar surface on the Roscosmos Luna-27 lander (2025).Now, GSFC and OU will now develop a compact ITMS instrument to study the near-surface lunar exosphere on board a CLPS Astrobotic lander at Lacus Mortis in 2021
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