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21.
Maestre R. Kurdahi F.J. Fernandez M. Hermida R. Bagherzadeh N. Singh H. 《Circuits and Systems Magazine, IEEE》2002,2(4):48-51
Reconfigurable computing is consolidating itself as a real alternative to ASICs (Application Specific Integrated Circuits) and general-purpose processors. The main advantage of reconfigurable computing derives from its unique combination of broad applicability, provided by the reconfiguration capability, and achievable performance, through the potential parallelism exploitation. The key aspects of the scheduling problem in a reconfigurable architecture are discussed, focusing on a task scheduling methodology for DSP and multimedia applications, as well as the context management and scheduling optimizations. 相似文献
22.
A general finite element approach to computing the modes of open-boundary waveguides is presented. This efficient and robust scheme applies equally to situations with real and complex propagation constants. By using a localised boundary impedance condition, the approach preserves the sparsity of the global matrices. A comparison with the well established infinite element technique and the analysis of a 2-D leaky optical structure are given as examples 相似文献
23.
R Avner BE Reubinoff A Simon BS Zentner A Friedmann S Mitrani-Rosenbaum N Laufer 《Canadian Metallurgical Quarterly》1996,2(1):60-62
Intracranial osteolipomas are rare lesions which occur in the region of the tuber cinereum. All cases reported to date have been incidental autopsy findings. We describe a patient who presented with a variety of neurological symptoms and had a typical osteolipoma surgically removed. 相似文献
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DJ Taatjes M Wadsworth PM Absher BE Sobel DJ Schneider 《Canadian Metallurgical Quarterly》1997,21(6):527-536
Vascular wall fibrinolytic system proteins are believed to play a pivotal role in atherogenesis. Tissue-type plasminogen activator (t-PA) and urokinase plasminogen activator (u-PA) influence persistence of luminal thrombi and proteolysis of extracellular matrix, respectively. The major physiologic inhibitor of t-PA and u-PA is plasminogen activator inhibitor type 1 (PAI-1). All three of these fibrinolytic system proteins have been detected in vascular endothelial cells, smooth muscle cells, and macrophages by light microscopic immunohistochemistry. This study was undertaken to delineate, by immunoelectron microscopy, the loci of PAI-1 in smooth muscle cells from intact morphologically normal and atherosclerotic human arteries as well as in isolated and cultured smooth muscle cells from arteries. In intact vessels, PAI-1 immunoreactivity was associated with contractile filaments in cells in both normal and atherosclerotic tissues. Lipid-laden smooth muscle cells in atherosclerotic vessels were mainly of the synthetic phenotype and displayed lesser amounts of PAI-1 associated with rough endoplasmic reticulum and contractile filaments. Isolated smooth muscle cells exhibited either a contractile or synthetic phenotype. In the cells with a contractile phenotype, PAI-1 was associated with the contractile elements, whereas in the cells with a synthetic phenotype, the PAI-1 was associated predominantly with elements of the endoplasmic reticulum. Because PAI-1 is associated predominantly with contractile filaments in smooth muscle cells, the net amount of immunodetectable PAI-1 appears to be greater in contractile compared with synthetic phenotype cells. 相似文献
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DM Clark PM Salkovskis LG Ost E Breitholtz KA Koehler BE Westling A Jeavons M Gelder 《Canadian Metallurgical Quarterly》1997,65(2):203-213
Cognitive accounts of panic predict that panic disorder patients will be particularly prone to misinterpret autonomic sensations. Several studies have produced results consistent with this prediction, but each is open to alternative interpretation. To clarify matters, 2 studies administered the Body Sensations Interpretation Questionnaire (BSIQ) to panic patients and controls. Panic patients were more likely to interpret ambiguous autonomic sensations as signs of immediately impending physical or mental disaster and were more likely than other anxiety disorder patients and nonpatients to believe these interpretations. In a 3rd study, a brief version of the BSIQ was shown to have satisfactory test-retest reliability, to change with treatment, and to discriminate treatments that varied in their effects on panic. 相似文献
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Submicronic powders of Bi4Ti3O12 with different morphologies were prepared by both the oxalate coprecipitation and the conventional mixing oxides methods. Compacts of the two calcined powders were sintered at 850–1100 °C in air, and the densification process was studied by non-isothermal and dilatometric experiments. A rapid densification (> 97% theoretical density) below 875 °C took place in the Bi4Ti3O12 oxalate powder which was attributed to an extremely uniform pore-size distribution in the green compact. The possible formation of a transient liquid which promotes densification also was taken into account. The development of plate-like morphology in the conventional Bi4Ti3O12 powder, broad pore-size distribution, and the plate-like colony formation, hindered rapid densification of the green compacts at low temperature. Microstructural development was studied; preliminary dielectric and electrical results are also reported. 相似文献
30.
The unquestionable advantages of multiple-input multiple-output (MIMO) systems are having a strong influence on the development of new wireless systems, both in wireless local-area networks (WLANs), and in those designed to offer broadband fixed wireless access (BFWA) services in wireless metropolitan-area networks (WMANs). The MIMO channel characterization in different environments and for different operating frequency bands is a crucial factor in the design of new systems and standards, and for adequate planning of existing systems. This article makes two main contributions. First, the experimental characterization of a 2 times 2 MIMO channel at a frequency of 2.4 GHz in a canonical outdoor-indoor scenario is presented. The channel characterization performed includes the analysis of the spatial correlation between the MIMO system subchannels and its impact on the channel capacity. Second, on the basis of the capacity results obtained, a proposal is made for the use of a 2 times 2 MIMO system in outdoor-indoor scenarios for BFWA applications in metropolitan environments. The proposal is based on the experimentally verified hypothesis that the path loss due to building penetration can be practically compensated for by the diversity gain of 2 times 2 systems 相似文献