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排序方式: 共有737条查询结果,搜索用时 27 毫秒
91.
92.
The authors present a variant of ESPRIT, known as the resolution enhanced (RE)-ESPRIT, that lowers resolution thresholds by incorporating left weighting of the signal eigenvectors to provide sector focusing. They discuss the advantages of this new left weighted ESPRIT. A compact expression for the asymptotic covariance matrix of the estimates is presented. Analytical and simulation results are included to show the resolution improvement of ESPRIT 相似文献
93.
This review of ongoing standards development highlights the interaction between the IEEE standards-making process and the norms of professional practice in software engineering. 相似文献
94.
This study explored the possibility that cognitive complexity can account for differences in the number of perceived dimensions with which individuals conceptualize pay satisfaction, as measured by the Pay Satisfaction Questionnaire. Using 2 independent samples of 1,969 certified teachers, it was found that mean group differences in cognitive complexity may account for the differences previously found in the literature. It was suggested that additional basic research be performed on how individuals conceptualize pay satisfaction and that more useful measures of cognitive complexity be developed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
95.
JA Shields CL Shields H Ehya E Buckley P De Potter 《Canadian Metallurgical Quarterly》1996,103(6):949-952
We report a case of priapism in an 11-year-old boy known to have Fabry's disease. High flow was confirmed by color flow Doppler ultrasound and intracorporal blood gas measurements. Successful treatment was achieved by unilateral percutaneous Gelfoam embolization of the left internal pudendal artery. Previously reported cases of priapism associated with Fabry's disease were identified through a MEDLINE search of the English literature and review of the publications. Five reported cases of priapism associated with Fabry's disease were found, including those of 3 children. A report of a child with high-flow priapism that did not respond to conventional treatment including cavernovenous shunting was noted. Priapsim associated with Fabry's disease may be caused by unregulated high arterial inflow. Early recognition of the underlying pathophysiology may identify those cases that would be amenable to percutaneous embolization therapy and may obviate the need to pursue other ineffective conventional treatments. 相似文献
96.
Seven patients with pulmonary regurgitation (PR), normal pulmonary artery (PA) pressures and large left-to-right atrial shunts are reported. Six had secundum atrial septal defects (ASD) and one had anomalous pulmonary venous drainage. These comprised 4% of 180 patients with atrial shunts and normal PA pressures. Pulmonary regurgitation was diagnosed clinically by mid-frequency diastolic decrescendo murmurs beginning after the pulmonic component of the second heart sound, and diagnoses were confirmed by catheterization. In two patients who had serial preoperative catheterizations over 8 and 16 years, PR progressed in one and was present only on the second study in the other. All patients underwent shunt correction, at which time the pulmonic anulus and artery appeared dilated, but the pulmonic valves were normal and did not require revision. In all patients the PR murmur disappeared after shunt correction alone, and on chest X-ray both PA and overall heart size decreased. Although it is known that pulmonary regurgitation occurs with atrial septal defects and pulmonary hypertension, the present study demonstrates that it also occurs with high flow atrial shunts, in which setting it has different implications and is reversible with shunt correction alone. 相似文献
97.
The purpose of this article was to provide a preliminary overview of the injury experiences among collegiate women athletes which were reported to the National Athletic Injury/Illness Reporting System (NAIRS) during its first 3 operational years (1975 to 1978). More dissimilarities in injury patterns were observed between women's sports than between comparable men and women's sports. The results thereby are interpreted that injuries to women athletes are essentially sport-related, not sex-related. Further investigative reports on women athletic injuries should be delimited to respective sports and over a period of time. Attention should be given to the patterns of injury within a sport, including shifts in patterns, so that practicable preventive measures can be perceived, implemented, and subsequently evaluated. 相似文献
98.
99.
Sliding friction experiments were conducted with gold, iron, and tantalum single crystals sliding on prismatic and basal orientations of pyrolytic graphite in various environments including, vacuum, oxygen, water vapor, nitrogen and hydrogen bromide. Surfaces were examined in the clean state and with various adsorbates present on the graphite surfaces. LEED, Auger spectroscopy, SEM, and EDXA were used to characterize the graphite surfaces. Results indicate that the prismatic and basal orientations do not contain nor do they chemisorb oxygen, water vapor, acetylene, or hydrogen bromide. All three metals exhibited higher friction on the prismatic than on the basal orientation and these metals transferred to the atomically clean prismatic orientation of pyrolytic graphite. No metal transfer to the graphite was observed in the presence of adsorbates at 760 torr. Ion bombardment of the graphite surface with nitrogen ions resulted in the adherence of nitrogen to the surface. 相似文献
100.
H Finch NA Pegg J McLaren A Lowdon R Bolton SJ Coote U Dyer JG Montana MR Owen M Dowle D Buckley BC Ross C Campbell C Dix C Mooney C Man-Tang C Patel 《Canadian Metallurgical Quarterly》1998,8(21):2955-2960
Synthesis of a variety of 5,5-trans fused lactones, related to compounds found in extracts of Lantana camara, has provided a series of novel acylating inhibitors of human thrombin, trypsin, chymotrypsin and human leucocyte elastase. The most effective thrombin inhibitor is 7 with an IC50 of 130 nM and a Kobs/[1] of 4,000 M-1 s-1. 相似文献