1,964 research outputs found
Development of a low actuation voltage RF MEMS switch
This paper reports on the design of a novel ultra low actuation voltage, low loss radio frequency micro-electro-mechanical system (RF MEMS) capacitive shunt switch. The concept of the switch relies on a mechanically unconstrained armature actuated over a coplanar waveguide using electrostatic forces. The minimum actuation voltage of the switch is <2V, with an isolation of 40dB and insertion loss <0.7dB at 78GHz
Expanding Confusion: common misconceptions of cosmological horizons and the superluminal expansion of the Universe
We use standard general relativity to illustrate and clarify several common
misconceptions about the expansion of the Universe. To show the abundance of
these misconceptions we cite numerous misleading, or easily misinterpreted,
statements in the literature. In the context of the new standard Lambda-CDM
cosmology we point out confusions regarding the particle horizon, the event
horizon, the ``observable universe'' and the Hubble sphere (distance at which
recession velocity = c). We show that we can observe galaxies that have, and
always have had, recession velocities greater than the speed of light. We
explain why this does not violate special relativity and we link these concepts
to observational tests. Attempts to restrict recession velocities to less than
the speed of light require a special relativistic interpretation of
cosmological redshifts. We analyze apparent magnitudes of supernovae and
observationally rule out the special relativistic Doppler interpretation of
cosmological redshifts at a confidence level of 23 sigma.Comment: To appear in Publications of the Astronomical Society of Australia,
26 pages (preprint format), 6 figures. Version 2: Section 4.1 revise
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Profiling electronic commerce research published in the Journal of Electronic Commerce Research
This article endeavors to profile the types of research published in the Journal of Electronic Commerce Research (JECR) from 2000 to 2007. An analysis of the published material includes examining variables such as citation analysis, universities associated with the most publications, geographic diversity, authors' backgrounds, subject areas most often investigated, and research methodologies. Like other profiling research, this work has implications for researchers, journal editors, universities, and research institutions. Since this work has utilized variables published in a previous study, the findings will allow a comparison to be made between JECR's profile and other Information Systems (IS) journals. Also, as this is the first profiling work for any Electronic Commerce Journal, it is thus likely to form the basis and motivation for profiling other journals in this area
Capture-zone scaling in island nucleation: phenomenological theory of an example of universal fluctuation behavior
In studies of island nucleation and growth, the distribution of capture
zones, essentially proximity cells, can give more insight than island-size
distributions. In contrast to the complicated expressions, ad hoc or derived
from rate equations, usually used, we find the capture-zone distribution can be
described by a simple expression generalizing the Wigner surmise from random
matrix theory that accounts for the distribution of spacings in a host of
fluctuation phenomena. Furthermore, its single adjustable parameter can be
simply related to the critical nucleus of growth models and the substrate
dimensionality. We compare with extensive published kinetic Monte Carlo data
and limited experimental data. A phenomenological theory sheds light on the
result.Comment: 5 pages, 4 figures, originally submitted to Phys. Rev. Lett. on Dec.
15, 2006; revised version v2 tightens and focuses the presentation,
emphasizes the importance of universal features of fluctuations, corrects an
error for d=1, replaces 2 of the figure
Size Effects in Carbon Nanotubes
The inter-shell spacing of multi-walled carbon nanotubes was determined by
analyzing the high resolution transmission electron microscopy images of these
nanotubes. For the nanotubes that were studied, the inter-shell spacing
is found to range from 0.34 to 0.39 nm, increasing with
decreasing tube diameter. A model based on the results from real space image
analysis is used to explain the variation in inter-shell spacings obtained from
reciprocal space periodicity analysis. The increase in inter-shell spacing with
decreased nanotube diameter is attributed to the high curvature, resulting in
an increased repulsive force, associated with the decreased diameter of the
nanotube shells.Comment: 4 pages. RevTeX. 4 figure
Research Notes : United States : Linkage of electrophoretic loci
In our studies of the inheritance of various electrophoretic variants, we have examined F2 segregation data from many crosses (see Gorman, 1983, for a listing). Many of these crosses were segregating for multiple loci, allowing linkage data to be collected. Table 1 represents a sunnnary of the linkage patterns we have observed between the listed electrophoretic loci (see Gorman and Kiang, 1978; Kiang, 1981; Gorman et al., 1983, concerning the establishment of these loci)
Research Notes : United States : Inheritance of a second leucine amino-peptidase locus and tests of its linkage with other loci
In dry soybean seed, only one leucine amino peptidase (LAP) anodal band was observed by acrylamide slab gel electrophoresis (Gorman et al., 1983). This band gradually declined in intensity and disappeared in all tissues about 10-12 days after germination. Three mobility variants (Rf\u27s 0.59, 0.53,and 0.58) were observed in the band, which was controlled by a single locus (Gor-man et al., 1983; Kiang and Gorman, 1983; Gorman, 1983)
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