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231.
232.
Selected micro- and nano-systems developed recently at the Physical Electronics Laboratory of ETH Zurich are reviewed: (i) a fluxgate microsystem for detection of the Earth's magnetic field; (ii) a capacitive chemical sensor microsystem for detection of volatile organic compounds in air; and (iii) a parallel scanning AFM chip. The micro- and nano-systems combine sensor structures and readout circuitry on a single chip and are fabricated using industrial CMOS technology in combination with post-processing micromachining and film deposition 相似文献
233.
Space Science Reviews - 相似文献
234.
Large-scale Coronal Heating, Clustering of Coronal Bright Points, and Concentration of Magnetic Flux
By combining quiet-region Fe XII coronal images from SOHO/EIT with magnetograms from NSO/Kitt Peak and from SOHO/MDI, we show that the population of network coronal bright points and the magnetic flux content of the network are both markedly greater under the bright half of the large-scale quiet corona than under the dim half. These results (1) support the view that the heating of the entire corona in quiet regions and coronal holes is driven by fine-scale magnetic activity (microflares, explosive events, spicules) seated low in the magnetic network, and (2) suggest that this large-scale modulation of the magnetic flux and coronal heating is a signature of giant convection cells. This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
235.
We review observations from Voyager 2 of CIRs and merged CIRs in the outer heliosphere. The rather simple characteristics
of the CIR-associated changes in plasma, magnetic field, and particles become more complex as observations are made at greater
and greater distances. Pickup ions from charge exchange undoubtedly play an important role in the structure, but the full
details are not yet understood.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
236.
The leading cause of worldwide aviation fatalities comes from inadvertently flying a perfectly operating aircraft into the ground or water. This type of accident is referred to as Controlled Flight Into Terrain (CFIT). Statistics show that introduction of the Ground Proximity Warning System (GPWS) into the scheduled air carrier turbojet fleet has been accompanied by a dramatic drop in the frequency of CFIT accidents. Training aids, videos, checklists, and procedural recommendations have also been produced to aid in CFIT risk reduction. Despite these actions, CFIT worldwide losses continue. Common characteristics of these continued accidents are a lack of installed GPWS or shortcomings of the current GPWS detection algorithms. The Enhanced Ground Proximity Warning Systems have been developed to address these shortcomings, and to provide enhanced situational awareness to the pilots such that CFIT accidents can become a thing of the past 相似文献
237.
A regulated peak-power tracking (RPPT) system for space power application is proposed. Large-signal stability analysis is provided to understand the main four different modes of operations of the system, as well as the mode transitions. A simple and effective control scheme for the system is also proposed. Small-signal analysis is performed thereafter to provide design optimization, and the predictions are verified by computer simulations 相似文献
238.
Ovshinsky S.R. Dhar S.K. Fetcenko M.A. Corrigan D.A. Reichman B. Young K. Fierro C. Venkatesan S. Gifford P. Koch J. 《Aerospace and Electronic Systems Magazine, IEEE》1999,14(5):17-23
While Ovonic NiMH batteries are already in high volume commercial production for portable applications, advances in materials technology have enabled performance improvements in specific energy (100 Wh/kg), specific power (600-1000 W/kg), high temperature operation, charge retention, and voltage stability. Concurrent with technology advances, Ovonic NiMH batteries have established performance and commercial milestones in electric vehicles, hybrid electric vehicles, as well as scooter, motorcycle and bicycle applications. As important as these advances, significant manufacturing cost reductions have also occurred which allow continued growth of NiMH technology. In this paper, advances in performance, applications and cost reduction are discussed with particular emphasis on the improved proprietary metal hydride and nickel hydroxide materials that make such advances possible 相似文献
239.
Yifeng Zhou Leung H. Blanchette M. 《IEEE transactions on aerospace and electronic systems》1999,35(2):410-418
In this work, we formulate the multiple sensor alignment problem in an Earth-centered Earth-fixed (ECEF) coordinate system. The alignment algorithm maps the sensor measurements to the ECEF coordinates using a geodetic transformation, and attributes the discrepancies in the Earth-referenced system reported by each sensor to the sensor biases. Sensor biases are then estimated using the least squares (LS) technique. Simulated and real-life radar data are used to evaluate the performance of the proposed algorithm. Comparisons are made to those algorithms based on the standard stereographic projection 相似文献
240.
Pulsone N.B. Raghavan R.S. 《IEEE transactions on aerospace and electronic systems》1999,35(3):903-916
Coherent signal detection in non-Gaussian interference is presently of interest in adaptive array applications. Conventional array detection algorithms inherently model the interference with a multivariate Gaussian random vector. However, non-Gaussian interference models are also under investigation for applications where the Gaussian assumption may not be appropriate. We analyze the performance of an adaptive array receiver for signal detection in interference modeled with a non-Gaussian distribution referred to as a spherically invariant random vector (SIRV). We first motivate this interference model with results from radar clutter measurements collected in the Mountain Top Program. Then we develop analytical expressions for the probability of false alarm and the probability of detection for the adaptive array receiver. Our analysis shows that the receiver has constant false alarm rate (CFAR) performance with respect to all the interference parameters. Some illustrative examples are included that compare the detection performance of this CFAR receiver with a receiver that has prior knowledge of the interference parameters 相似文献