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

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 ${\hat{d}_{002}}$ 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

Saphenous vein graft aneurysm with graft-enteric fistula after renal artery bypass

A 65-year-old female presented with upper gastrointestinal hemorrhage thirty years following an aorta-to-right renal artery bypass constructed with saphenous vein. Upper endoscopy demonstrated a duodenal ulcer, and a CAT scan demonstrated aneurysmal degeneration of her renal artery bypass with duodenal impingement. Laparotomy demonstrated erosion of the aneurysm through the posterior wall of the duodenum; extra-anatomic renovascular reconstruction and primary duodenal repair was performed. Although aneurysmal degeneration of intraabdominal saphenous vein grafts is well described and rupture likewise reported, this report represents the first description of an intraabdominal autogenous vein graft aneurysm presenting with gastrointestinal erosion and fistula

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)