101,699 research outputs found
Dc pin-to-pin testing of integrated circuits
External pin-to-pin nondestructive testing procedure measures the electrical characteristics of each element in an integrated circuit. The procedure involves choosing specific pairs of pins and applying appropriate test voltages to them
Solid-state recoverable fuse functions as circuit breaker
Molded, conductive-epoxy recoverable fuse protects electronic circuits during overload conditions, and then permits them to continue to function immediately after the overload condition is removed. It has low resistance at ambient temperature, and high resistance at an elevated temperature
What is tested when experiments test that quantum dynamics is linear
Experiments that look for nonlinear quantum dynamics test the fundamental
premise of physics that one of two separate systems can influence the physical
behavior of the other only if there is a force between them, an interaction
that involves momentum and energy. The premise is tested because it is the
assumption of a proof that quantum dynamics must be linear. Here variations of
a familiar example are used to show how results of nonlinear dynamics in one
system can depend on correlations with the other. Effects of one system on the
other, influence without interaction between separate systems, not previously
considered possible, would be expected with nonlinear quantum dynamics. Whether
it is possible or not is subject to experimental tests together with the
linearity of quantum dynamics. Concluding comments and questions consider
directions our thinking might take in response to this surprising unprecedented
situation.Comment: 14 pages, Title changed, sentences adde
Dynamics of hadron strong production and decay
We generalize results of lattice QCD to determine the spin-dependent
symmetries and factorization properties of meson production in OZI allowed
processes. This explains some conjectures previously made in the literature
about axial meson decays and gives predictions for exclusive decays of vector
charmonia, including ways of establishing the structure of Y(4260) and Y(4325)
from their S-wave decays. Factorization gives a selection rule which forbids
near threshold with the tensor meson in helicity 2. The
relations among amplitudes for double charmonia production \e^+e^-\to
\psi\chi_{0,1,2} are expected to differ from the analagous relations among
light flavour production such as \e^+e^-\to \omega f_{0,1,2}.Comment: 13 pages; journal versio
Looking for a gift of Nature: Hadron loops and hybrid mixing
We investigate how coupling of valence q qbar to meson pairs can modify the
properties of conventional q qbar and hybrid mesons. In a symmetry limit the
mixing between hybrids and conventional q qbar with the same J^PC is shown to
vanish. Flavor mixing between heavy and light q qbar due to meson loops is
shown to be dual to the results of gluon mediated pQCD, and qualitatively
different from mixing involving light flavors alone. The validity of the OZI
rule for conventional q qbar and hybrid mesons is discussed.Comment: v2: added important references and discussion of previous literature;
results and conclusions unchanged. 8 pages, 2 figure
Quantum diffusion in liquid water from ring polymer molecular dynamics
We have used the ring polymer molecular-dynamics method to study the translational and orientational motions in an extended simple point charge model of liquid water under ambient conditions. We find, in agreement with previous studies, that quantum-mechanical effects increase the self-diffusion coefficient D and decrease the relaxation times around the principal axes of the water molecule by a factor of around 1.5. These results are consistent with a simple Stokes-Einstein picture of the molecular motion and suggest that the main effect of the quantum fluctuations is to decrease the viscosity of the liquid by about a third. We then go on to consider the system-size scaling of the calculated self-diffusion coefficient and show that an appropriate extrapolation to the limit of infinite system size increases D by a further factor of around 1.3 over the value obtained from a simulation of a system containing 216 water molecules. These findings are discussed in light of the widespread use of classical molecular-dynamics simulations of this sort of size to model the dynamics of aqueous systems
Quantum diffusion in liquid para-hydrogen from ring-polymer molecular dynamics
We have used the ring-polymer molecular dynamics method to calculate approximate Kubo-transformed velocity autocorrelation functions and self-diffusion coefficients for low-pressure liquid para-hydrogen at temperatures of 25 and 14 K. The resulting diffusion coefficients are shown to be consistent with experimental shear viscosities and the established finite-size relation D(L)~=D([infinity])–2.837kBT/6pietaL, where kB is the Boltzmann constant, T the absolute temperature, eta the shear viscosity, and L the length of the (cubic) simulation cell. The diffusion coefficients D(L) obtained in simulations with finite system sizes are therefore too small. However, the extrapolation to infinite system size corrects this deficiency and leads to excellent agreement with experimental results. This both demonstrates the influence of system-size effects on quantum mechanical diffusion coefficients and provides further evidence that ring-polymer molecular dynamics is an accurate as well as practical way of including quantum effects in condensed phase molecular dynamics
Automated Reasoning over Deontic Action Logics with Finite Vocabularies
In this paper we investigate further the tableaux system for a deontic action
logic we presented in previous work. This tableaux system uses atoms (of a
given boolean algebra of action terms) as labels of formulae, this allows us to
embrace parallel execution of actions and action complement, two action
operators that may present difficulties in their treatment. One of the
restrictions of this logic is that it uses vocabularies with a finite number of
actions. In this article we prove that this restriction does not affect the
coherence of the deduction system; in other words, we prove that the system is
complete with respect to language extension. We also study the computational
complexity of this extended deductive framework and we prove that the
complexity of this system is in PSPACE, which is an improvement with respect to
related systems.Comment: In Proceedings LAFM 2013, arXiv:1401.056
ERTS-1 imagery use in reconnaissance prospecting: Evaluation of commercial utility of ERTS-1 imagery in structural reconnaissance for minerals and petroleum
The author has identified the following significant results. This study was performed to investigate applications of ERTS-1 imagery in commercial reconnaissance for mineral and hydrocarbon resources. ERTS-1 imagery collected over five areas in North America (Montana; Colorado; New Mexico-West Texas; Superior Province, Canada; and North Slope, Alaska) has been analyzed for data content including linears, lineaments, and curvilinear anomalies. Locations of these features were mapped and compared with known locations of mineral and hydrocarbon accumulations. Results were analyzed in the context of a simple-shear, block-coupling model. Data analyses have resulted in detection of new lineaments, some of which may be continental in extent, detection of many curvilinear patterns not generally seen on aerial photos, strong evidence of continental regmatic fracture patterns, and realization that geological features can be explained in terms of a simple-shear, block-coupling model. The conculsions are that ERTS-1 imagery is of great value in photogeologic/geomorphic interpretations of regional features, and the simple-shear, block-coupling model provides a means of relating data from ERTS imagery to structures that have controlled emplacement of ore deposits and hydrocarbon accumulations, thus providing a basis for a new approach for reconnaissance for mineral, uranium, gas, and oil deposits and structures
Real-time growth rate for general stochastic SIR epidemics on unclustered networks
Networks have become an important tool for infectious disease epidemiology.
Most previous theoretical studies of transmission network models have either
considered simple Markovian dynamics at the individual level, or have focused
on the invasion threshold and final outcome of the epidemic. Here, we provide a
general theory for early real-time behaviour of epidemics on large
configuration model networks (i.e. static and locally unclustered), in
particular focusing on the computation of the Malthusian parameter that
describes the early exponential epidemic growth. Analytical, numerical and
Monte-Carlo methods under a wide variety of Markovian and non-Markovian
assumptions about the infectivity profile are presented. Numerous examples
provide explicit quantification of the impact of the network structure on the
temporal dynamics of the spread of infection and provide a benchmark for
validating results of large scale simulations.Comment: 45 pages, 8 figures, submitted to Mathematical Biosciences on
29/11/2014; Version 2: resubmitted on 15/04/2015; accepted on 17/04/2015.
Changes: better explanations in introduction; restructured section 3.3 (3.3.3
added); section 6.3.1 added; more precise terminology; typos correcte
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