149,936 research outputs found
Detection of, and communication with space vehicles during atmospheric entry, problems in simulation
Detection of, and communication with spacecraft during atmospheric entry - simulation problem
Axial Anomaly and the Nucleon Spin
In this letter, we have taken a particular Lagrangian, which was introduced
to resolve U(1) problem, as an effective QCD Lagrangian, and have derived a
formula of the quark content of the nucleon spin. The difference between quark
content of the proton (\Delta\Sigma_p) and that of the neutron (\Delta\Sigma_n)
is evaluated by this formula. Neglecting the higher-order isospin corrections,
this formula can reduce to Efremov's results in the large N_c limit.Comment: (1) A few changes and corrections made following Referee. (2) The
difference between quark content of the proton (\Delta\Sigma_p) and that of
the neutron (\Delta\Sigma_n) is evaluated. Neglecting the higher-order
isospin corrections, this formula can reduce to Efremov's results in the
large N_c limi
The stability of new transparent polymeric materials: The epoxy trimethoxyboroxine system. Part 1: The preparation, characterization and curing of epoxy resins and their copolymers
The effects of resin composition, curing conditions fillers, and flame retardant additives on the flammability of diglycidyl ether of bisphenol-A (DGEBA) as measured by the oxygen index is examined. The oxygen index of DGEBA cured with various curing agents was between 0.198 to 0.238. Fillers and flame retardant additives can increase the oxygen index dependent on the material and the amount used. Changes in the basic cured resin properties can be anticipated with the addition of noncompatible additives. High flame resistant epoxy resins with good stability and mechanical properties are investigated
Block-Structured Supermarket Models
Supermarket models are a class of parallel queueing networks with an adaptive
control scheme that play a key role in the study of resource management of,
such as, computer networks, manufacturing systems and transportation networks.
When the arrival processes are non-Poisson and the service times are
non-exponential, analysis of such a supermarket model is always limited,
interesting, and challenging.
This paper describes a supermarket model with non-Poisson inputs: Markovian
Arrival Processes (MAPs) and with non-exponential service times: Phase-type
(PH) distributions, and provides a generalized matrix-analytic method which is
first combined with the operator semigroup and the mean-field limit. When
discussing such a more general supermarket model, this paper makes some new
results and advances as follows: (1) Providing a detailed probability analysis
for setting up an infinite-dimensional system of differential vector equations
satisfied by the expected fraction vector, where "the invariance of environment
factors" is given as an important result. (2) Introducing the phase-type
structure to the operator semigroup and to the mean-field limit, and a
Lipschitz condition can be obtained by means of a unified matrix-differential
algorithm. (3) The matrix-analytic method is used to compute the fixed point
which leads to performance computation of this system. Finally, we use some
numerical examples to illustrate how the performance measures of this
supermarket model depend on the non-Poisson inputs and on the non-exponential
service times. Thus the results of this paper give new highlight on
understanding influence of non-Poisson inputs and of non-exponential service
times on performance measures of more general supermarket models.Comment: 65 pages; 7 figure
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