6,866 research outputs found
Total integrated dose testing of solid-state scientific CD4011, CD4013, and CD4060 devices by irradiation with CO-60 gamma rays
The total integrated dose response of three CMOS devices manufactured by Solid State Scientific has been measured using CO-60 gamma rays. Key parameter measurements were made and compared for each device type. The data show that the CD4011, CD4013, and CD4060 produced by this manufacturers should not be used in any environments where radiation levels might exceed 1,000 rad(Si)
Evidence for spin liquid ground state in SrDyO frustrated magnet probed by muSR
Muon spin relaxation (SR) measurements were carried out on
SrDyO, a frustrated magnet featuring short range magnetic correlations
at low temperatures. Zero-field muon spin depolarization measurements
demonstrate that fast magnetic fluctuations are present from K down to
20 mK. The coexistence of short range magnetic correlations and fluctuations at
mK indicates that SrDyO features a spin liquid ground state.
Large longitudinal fields affect weakly the muon spin depolarization, also
suggesting the presence of fast fluctuations. For a longitudinal field of
T, a non-relaxing asymmetry contribution appears below K,
indicating considerable slowing down of the magnetic fluctuations as
field-induced magnetically-ordered phases are approached.Comment: 6 pages, 4 figures, to be published as a proceeding of HFM2016 in
Journal of Physics: Conference Series (JPCS
Timescale for equilibration of N/Z gradients in dinuclear systems
Equilibration of N/Z in binary breakup of an excited and transiently deformed
projectile-like fragment (PLF*), produced in peripheral collisions of 64Zn +
27Al, 64Zn, 209Bi at E/A = 45 MeV, is examined. The composition of emitted
light fragments (3<=Z<=6) changes with the decay angle of the PLF*. The most
neutron-rich fragments observed are associated with a small rotation angle. A
clear target dependence is observed with the largest initial N/Z correlated
with the heavy, neutron-rich target. Using the rotation angle as a clock, we
deduce that N/Z equilibration persists for times as long as 3-4 zs (1zs = 1 x
10^-21 s = 300 fm/c). The rate of N/Z equilibration is found to depend on the
initial neutron gradient within the PLF*.Comment: 6 pages, 4 figure
Total-dose radiation effects data for semiconductor devices. 1985 supplement. Volume 2, part A
Steady-state, total-dose radiation test data, are provided in graphic format for use by electronic designers and other personnel using semiconductor devices in a radiation environment. The data were generated by JPL for various NASA space programs. This volume provides data on integrated circuits. The data are presented in graphic, tabular, and/or narrative format, depending on the complexity of the integrated circuit. Most tests were done using the JPL or Boeing electron accelerator (Dynamitron) which provides a steady-state 2.5 MeV electron beam. However, some radiation exposures were made with a Cobalt-60 gamma ray source, the results of which should be regarded as only an approximate measure of the radiation damage that would be incurred by an equivalent electron dose
Total-dose radiation effects data for semiconductor devices: 1985 supplement, volume 1
Steady-state, total-dose radiation test data are provided, in graphic format, for use by electronic designers and other personnel using semiconductor devices in a radiation environment. The data were generated by JPL for various NASA space programs. The document is in two volumes: Volume 1 provides data on diodes, bipolar transistors, field effect transistors, and miscellaneous semiconductor types, and Volume 2 provides total-dose radiation test data on integrated circuits. Volume 1 of this 1985 Supplement contains new total-dose radiation test data generated since the August 1, 1981 release date of the original Volume 1. Publication of Volume 2 of the 1985 Supplement will follow that of Volume 1 by approximately three months
Supersymmetric free-damped oscillators: Adaptive observer estimation of the Riccati parameter
A supersymmetric class of free damped oscillators with three parameters has
been obtained in 1998 by Rosu and Reyes through the factorization of the Newton
equation. The supplementary parameter is the integration constant of the
general Riccati solution. The estimation of the latter parameter is performed
here by employing the recent adaptive observer scheme of Besancon et al., but
applied in a nonstandard form in which a time-varying quantity containing the
unknown Riccati parameter is estimated first. Results of computer simulations
are presented to illustrate the good feasibility of this approach for a case in
which the estimation is not easily accomplished by other meansComment: 8 pages, 6 figure
On the Hausdorff volume in sub-Riemannian geometry
For a regular sub-Riemannian manifold we study the Radon-Nikodym derivative
of the spherical Hausdorff measure with respect to a smooth volume. We prove
that this is the volume of the unit ball in the nilpotent approximation and it
is always a continuous function. We then prove that up to dimension 4 it is
smooth, while starting from dimension 5, in corank 1 case, it is C^3 (and C^4
on every smooth curve) but in general not C^5. These results answer to a
question addressed by Montgomery about the relation between two intrinsic
volumes that can be defined in a sub-Riemannian manifold, namely the Popp and
the Hausdorff volume. If the nilpotent approximation depends on the point (that
may happen starting from dimension 5), then they are not proportional, in
general.Comment: Accepted on Calculus and Variations and PD
Polarization instabilities in a two-photon laser
We describe the operating characteristics of a new type of quantum oscillator
that is based on a two-photon stimulated emission process. This two-photon
laser consists of spin-polarized and laser-driven K atoms placed in a
high-finesse transverse-mode-degenerate optical resonator, and produces a beam
with a power of 0.2 W at a wavelength of 770 nm. We observe
complex dynamical instabilities of the state of polarization of the two-photon
laser, which are made possible by the atomic Zeeman degeneracy. We conjecture
that the laser could emit polarization-entangled twin beams if this degeneracy
is lifted.Comment: Accepted by Physical Review Letters. REVTeX 4 pages, 4 EPS figure
Restricted feedback control of one-dimensional maps
Dynamical control of biological systems is often restricted by the practical
constraint of unidirectional parameter perturbations. We show that such a
restriction introduces surprising complexity to the stability of
one-dimensional map systems and can actually improve controllability. We
present experimental cardiac control results that support these analyses.
Finally, we develop new control algorithms that exploit the structure of the
restricted-control stability zones to automatically adapt the control feedback
parameter and thereby achieve improved robustness to noise and drifting system
parameters.Comment: 29 pages, 9 embedded figure
The Band Excitation Method in Scanning Probe Microscopy for Rapid Mapping of Energy Dissipation on the Nanoscale
Mapping energy transformation pathways and dissipation on the nanoscale and
understanding the role of local structure on dissipative behavior is a
challenge for imaging in areas ranging from electronics and information
technologies to efficient energy production. Here we develop a novel Scanning
Probe Microscopy (SPM) technique in which the cantilever is excited and the
response is recorded over a band of frequencies simultaneously rather than at a
single frequency as in conventional SPMs. This band excitation (BE) SPM allows
very rapid acquisition of the full frequency response at each point (i.e.
transfer function) in an image and in particular enables the direct measurement
of energy dissipation through the determination of the Q-factor of the
cantilever-sample system. The BE method is demonstrated for force-distance and
voltage spectroscopies and for magnetic dissipation imaging with sensitivity
close to the thermomechanical limit. The applicability of BE for various SPMs
is analyzed, and the method is expected to be universally applicable to all
ambient and liquid SPMs.Comment: 32 pages, 9 figures, accepted for publication in Nanotechnolog
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