It is more than 15 years since high frequency oscillatory ventilation (HFOV) was first described as a technique of ventilation [ 1 ]. In the intervening period it has passed through a phase of being a physiological curiosity, where it could be demonstrated that normal gas exchange could be maintained using tidal volumes much smaller than deadspace at rates much greater than what was then consid...

[1] Using the updated Singapore wind from 1953 to 2007 for the lower stratosphere 70–10 hPa, courtesy of Barbara Naujokat of Free University of Berlin, we examine the variation of the period of the Quasi-Biennial Oscillation (QBO) as a function of height and its modulation in time by the 11-year solar cycle. The analysis is supplemented by the ERA-40 reanalysis up to 1 hPa. Previously, it was r...

Using inductively-coupled-plasma reactive ion etching (ICP-RIE), recessed 1 mm gate-length enhancement-mode (E-mode) AlGaN=GaN high electron mobility transistors (HEMTs) were fabricated. These 1 mm gate-length devices exhibited maximum drain current density of 470 mA=mm, extrinsic transconductance of 248 mS=mm and threshold voltage of 75 mV. These characteristics are much higher than previously...

introduction long-term annual extreme climate events, especially temperature and precipitation, have generally been used as indicators for the assessment of climate change. one of the most changeable climatic variables in time and space is precipitation. there are great number of research papers focusing on extreme precipitation on global, regional and national scales have been written. the res...

Abstract We present a selective laterally wet etched collector InP/InGaAs/InGaAsP double heterojunction bipolar transistor (DHBT) with a quaternary step graded base collector structure. This device shows a DC current gain of = 70 over a large collector current range, a breakdown voltage of BVCE0 = 10.5 V, and a maximal collector emitter voltage of more than 5.5 V at 105 A/cm2 collector current ...

Radio frequency transistors based on ultra-high purity semiconducting carbon nanotubes with superior extrinsic maximum oscillation frequency Yu Cao, Yuchi Che, Hui Gui, Xuan Cao, and Chongwu Zhou () 1 Department of Electrical Engineering, University of Southern California, Los Angeles, CA 90089, USA 2 Department of Chemical Engineering and Materials Science, University of Southern California, ...

Current starved VCO is simple ring oscillator consisting of cascaded inverters. Differential ring oscillator has a differential output to reject common-mode noise, power supply noise and so on. In this paper we have designed and simulated Current Starved VCO and Differential VCO for PLL in Tanner 13.0v 0.18μm digital CMOS process. Performance comparison is done in terms of high oscillation freq...

A fully integrated single-ended output pushpush oscillator is realized using an advanced 0.2μm SiGe HBT process. Up to –5 dBm output power is achieved at 180 GHz using a technology with a transition frequency fT of 200 GHz and maximum oscillation frequency fMAX of 275 GHz. Preliminary phase noise measurements show a phase noise of less than –90 dBc/Hz at 1 MHz offset from the 180 GHz carrier.

Introduction: Microbubbles are widely used as contrast agent in diagnostic ultrasound. Recently they have shown good potential for applications in the therapeutic field such as drug delivery to the brain. Recent studies have shown focused ultrasound in conjunction with injected micro-bubbles could temporarily disrupt blood-brain barrier and let therapeutic agents transport into...