7,835 research outputs found
Properties of material in the submillimeter wave region (instrumentation and measurement of index of refraction)
The Properties of Materials in the Submillimeter Wave Region study was initiated to instrument a system and to make measurements of the complex index of refraction in the wavelength region between 0.1 to 1.0 millimeters. While refractive index data is available for a number of solids and liquids there still exists a need for an additional systematic study of dielectric properties to add to the existing data, to consider the accuracy of the existing data, and to extend measurements in this wavelength region for other selected mateials. The materials chosen for consideration would be those with useful thermal, mechanical, and electrical characteristics. The data is necessary for development of optical components which, for example, include beamsplitters, attenuators, lenses, grids, all useful for development of instrumentation in this relatively unexploited portion of the spectrum
Evaluation of user reactions to a prototype on-line information retrieval system
Human reaction to operation of document search and retrieval syste
The Lueders Postulate and the Distinguishability of Observables
The Lueders postulate is reviewed and implications for the distinguishability
of observables are discussed. As an example the distinguishability of two
similar observables for spin-1/2 particles is described. Implementation issues
are briefly analyzed.Comment: Submitted to the proceedings of ICFNCS, Hong Kong, 200
Resonators coupled to voltage-biased Josephson junctions: From linear response to strongly driven nonlinear oscillations
Motivated by recent experiments, where a voltage biased Josephson junction is
placed in series with a resonator, the classical dynamics of the circuit is
studied in various domains of parameter space. This problem can be mapped onto
the dissipative motion of a single degree of freedom in a nonlinear
time-dependent potential, where in contrast to conventional settings the
nonlinearity appears in the driving while the static potential is purely
harmonic. For long times the system approaches steady states which are analyzed
in the underdamped regime over the full range of driving parameters including
the fundamental resonance as well as higher and sub-harmonics. Observables such
as the dc-Josephson current and the radiated microwave power give direct
information about the underlying dynamics covering phenomena as bifurcations,
irregular motion, up- and down conversion. Due to their tunability, present and
future set-ups provide versatile platforms to explore the changeover from
linear response to strongly nonlinear behavior in driven dissipative systems
under well defined conditions.Comment: 12 pages, 11 figure
Robust non-adiabatic molecular dynamics for metals and insulators
We present a new formulation of the correlated electron-ion dynamics (CEID)
scheme, which systematically improves Ehrenfest dynamics by including quantum
fluctuations around the mean-field atomic trajectories. We show that the method
can simulate models of non-adiabatic electronic transitions, and test it
against exact integration of the time-dependent Schroedinger equation. Unlike
previous formulations of CEID, the accuracy of this scheme depends on a single
tunable parameter which sets the level of atomic fluctuations included. The
convergence to the exact dynamics by increasing the tunable parameter is
demonstrated for a model two level system. This algorithm provides a smooth
description of the non-adiabatic electronic transitions which satisfies the
kinematic constraints (energy and momentum conservation) and preserves quantum
coherence. The applicability of this algorithm to more complex atomic systems
is discussed.Comment: 36 pages, 5 figures. Accepted for publication in Journal of Chemical
Physic
Laser-Doppler gas-velocity instrument
Three-D instrument using a laser light source measures both turbulence and mean velocity of subsonic and supersonic gas flows. This instrument is based on the measurement of the Doppler frequency shift of light waves scattered by moving particles in the gas stream
Wide band frequency tracker performance and design of an all angle laser Doppler optical homodyne receiver, ground wind and wind tunnel measurements program, volume 2 Final report
Analysis and measurement of characteristics of wide band frequency trackers and design and fabrication of all angle laser Doppler velocimete
Productivity gains, intersectoral linkages, and trade : Indonesian manufacturing, 1980-1996
The importance of R&D spillovers for productivity growth has been well-documented in the literature. While studies in the context of developed countries have extensively focused on sectoral linkages, research on North-South spillovers has been largely confined to the aggregate level. This paper assesses the contribution of international R&D spillovers to manufacturing performance in Indonesia at the sectoral level of manufacturing. Drawing on OECD and Indonesian data sources, we consider two distinct periods: an early period characterised by intense policy regulations followed by a period of liberalisation and reform. Our results indicate a significant contribution of international technology spillovers to the performance of Indonesian manufacturing, especially after liberalisation, with the notable importance of sectoral characteristics and industrial market structure. Keywords: Indonesia, productivity growth, technology spillovers, international trade, market structur
Quantum Limits of Measurements Induced by Multiplicative Conservation Laws: Extension of the Wigner-Araki-Yanase Theorem
The Wigner-Araki-Yanase (WAY) theorem shows that additive conservation laws
limit the accuracy of measurements. Recently, various quantitative expressions
have been found for quantum limits on measurements induced by additive
conservation laws, and have been applied to the study of fundamental limits on
quantum information processing. Here, we investigate generalizations of the WAY
theorem to multiplicative conservation laws. The WAY theorem is extended to
show that an observable not commuting with the modulus of, or equivalently the
square of, a multiplicatively conserved quantity cannot be precisely measured.
We also obtain a lower bound for the mean-square noise of a measurement in the
presence of a multiplicatively conserved quantity. To overcome this noise it is
necessary to make large the coefficient of variation (the so-called relative
fluctuation), instead of the variance as is the case for additive conservation
laws, of the conserved quantity in the apparatus.Comment: 8 pages, REVTEX; typo added, to appear in PR
Regulation of cargo transfer between ESCRT-0 and ESCRT-I complexes by flotillin-1 during endosomal sorting of ubiquitinated cargo
Ubiquitin-dependent sorting of membrane proteins in endosomes directs them to lysosomal degradation. In the case of receptors such as the epidermal growth factor receptor (EGFR), lysosomal degradation is important for the regulation of downstream signalling. Ubiquitinated proteins are recognised in endosomes by the endosomal sorting complexes required for transport (ESCRT) complexes, which sequentially interact with the ubiquitinated cargo. Although the role of each ESCRT complex in sorting is well established, it is not clear how the cargo is passed on from one ESCRT to the next. We here show that flotillin-1 is required for EGFR degradation, and that it interacts with the subunits of ESCRT-0 and -I complexes (hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs) and Tsg101). Flotillin-1 is required for cargo recognition and sorting by ESCRT-0/Hrs and for its interaction with Tsg101. In addition, flotillin-1 is also required for the sorting of human immunodeficiency virus 1 Gag polyprotein, which mimics ESCRT-0 complex during viral assembly. We propose that flotillin-1 functions in cargo transfer between ESCRT-0 and -I complexes
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