471 research outputs found
Threshold detector produces narrow pulses at high repetition rates
Solid state device generates fixed width output pulses from variable width input pulses in the nanosecond range. The circuit produces pulse repetition rates in the megacycle range and exhibits low power drain
Resettable monostable pulse generator Patent
Development and characteristics of resettable monostable pulse generator with charge rundown-timing circui
Some variations of tunnel diode pulse generator circuits
Variations of tunnel diode pulse generator circuit
Collective Dynamics of Solitons and Inequivalent Quantizations
The collective dynamics of solitons with a coset space G/H as moduli space is
studied. It is shown that the collective band for a vibrational state is given
by the inequivalent coset space quantization corresponding to the
representation of H carried by the vibration.Comment: 6 pages, revte
Thermodynamics of Coarse Grained Models of Super-Cooled Liquids
In recent papers, we have argued that kinetically constrained coarse grained
models can be applied to understand dynamic properties of glass forming
materials, and we have used this approach in various applications that appear
to validate this view. In one such paper [J.P. Garrahan and D. Chandler, Proc.
Nat. Acad. Sci. USA 100, 9710 (2003)], among other things we argued that this
approach also explains why the heat capacity discontinuity at the glass
transition is generally larger for fragile materials than for strong materials.
In the preceding article, Biroli, Bouchaud and Tarjus (BB&T) [cond-mat/0412024]
have objected to our explanation on this point, arguing that the class of
models we apply is inconsistent with both the absolute size and temperature
dependence of the experimental specific heat. Their argument, however, neglects
parameters associated with the coarse graining. Accounting for these
parameters, we show here that our treatment of dynamics is not inconsistent
with heat capacity discontinuities.Comment: 5 pages, 2 figures. Revised version to appear in J. Chem. Phy
Space-time Thermodynamics of the Glass Transition
We consider the probability distribution for fluctuations in dynamical action
and similar quantities related to dynamic heterogeneity. We argue that the
so-called "glass transition" is a manifestation of low action tails in these
distributions where the entropy of trajectory space is sub-extensive in time.
These low action tails are a consequence of dynamic heterogeneity and an
indication of phase coexistence in trajectory space. The glass transition,
where the system falls out of equilibrium, is then an order-disorder phenomenon
in space-time occurring at a temperature T_g which is a weak function of
measurement time. We illustrate our perspective ideas with facilitated lattice
models, and note how these ideas apply more generally.Comment: 5 pages, 4 figure
Simple circuit produces high-speed, fixed duration pulses
Circuit generates an output pulse of fixed width from a variable width input pulse. The circuit consists of a tunnel diode in parallel with an inductance driven by a constant current generator. It is used for pulsed communication equipment design
Fluctuating observation time ensembles in the thermodynamics of trajectories
The dynamics of stochastic systems, both classical and quantum, can be
studied by analysing the statistical properties of dynamical trajectories. The
properties of ensembles of such trajectories for long, but fixed, times are
described by large-deviation (LD) rate functions. These LD functions play the
role of dynamical free-energies: they are cumulant generating functions for
time-integrated observables, and their analytic structure encodes dynamical
phase behaviour. This "thermodynamics of trajectories" approach is to
trajectories and dynamics what the equilibrium ensemble method of statistical
mechanics is to configurations and statics. Here we show that, just like in the
static case, there is a variety of alternative ensembles of trajectories, each
defined by their global constraints, with that of trajectories of fixed total
time being just one of these. We show that an ensemble of trajectories where
some time-extensive quantity is constant (and large) but where total
observation time fluctuates, is equivalent to the fixed-time ensemble, and the
LD functions that describe one ensemble can be obtained from those that
describe the other. We discuss how the equivalence between generalised
ensembles can be exploited in path sampling schemes for generating rare
dynamical trajectories.Comment: 12 pages, 5 figure
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