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61.
A nonlinear regeneration pulsed oscillator driven by a monochromatic source has been built. Subharmonics of the resonance carrier/modulation are measured with an accuracy of 10-10 thanks to the use of a double beats measurement set-up. The multiscale analysis of frequency readings reveals a rich fine structure which is in agreement with the nonlinear topological approach of synchronized states. 相似文献
62.
63.
Neuropeptide Y (NPY) is a unique modulator of renal function that enhances urine flow and sodium excretion despite marked reductions in renal blood flow. We investigated whether the cyclooxygenase inhibitor indomethacin alters the renal NPY effects in anesthetized rats. Treatment with 5 mg/kg indomethacin i.p. lowered urinary prostaglandin excretion by approximately 85%. Systemic infusion of NPY elevated mean arterial pressure by approximately 15 mm Hg and renovascular resistance by approximately 8.0 mm Hg/ml/min, whereas the related peptide YY3-36 (PYY3-36) did not. Nevertheless, both peptides enhanced urine flow rate by approximately 250 and approximately 100 microl/15 min, respectively, and sodium excretion by approximately 15 micromol/15 min. Treatment with indomethacin did not affect NPY- and PYY3-36-induced alterations of systemic and renovascular hemodynamics but completely abolished NPY- and PYY3-36-induced diuresis and natriuresis. Endogenous creatinine clearance was not affected by any treatment. We conclude that cyclooxygenase-derived arachidonic acid metabolites are not involved in the systemic or renal hemodynamic effects of NPY and PYY3-36 but mediate NPY- and PYY3-36-induced diuresis and natriuresis. 相似文献
64.
We describe the case of a young woman with pain on turning her head attributable to a malformation of the hyoid bone. Diagnosis was established using spiral computed tomography with the patient's neck in the position of greatest discomfort and with 3-dimensional reconstruction of the hyoid bone. Prior conventional radiography and magnetic resonance imaging did not aid in finding a diagnosis. After surgical removal of both greater cornua of the hyoid bone there was a complete relief of symptoms. 相似文献
65.
Summary Geffert has shown that earch recursively enumerable languageL over can be expressed in the formL{h(x)
–1
g(x)x in
+}
* where is an alphabet andg, h is a pair of morphisms. Our purpose is to give a simple proof for Geffert's result and then sharpen it into the form where both of the morphisms are nonerasing. In our method we modify constructions used in a representation of recursively enumerable languages in terms of equality sets and in a characterization of simple transducers in terms of morphisms. As direct consequences, we get the undecidability of the Post correspondence problem and various representations ofL. For instance,L =(L
0)
* whereL
0 is a minimal linear language and is the Dyck reductiona, A. 相似文献
66.
Michel Brusin 《Materials and Structures》1990,23(2):79-80
Editorial
All a RILEM technical recommendation should be 相似文献67.
E. A. Fitzgerald Y. -H. Xie D. Brasen M. L. Green J. Michel P. E. Freeland B. E. Weir 《Journal of Electronic Materials》1990,19(9):949-955
We have grown Ge x Si1-x (0 <x < 0.20,1000–3000Å thick) on small growth areas etched in the Si substrate. Layers were grown using both molecular beam epitaxy (MBE) at 550° C and rapid thermal chemical vapor deposition (RTCVD) at 900° C. Electron beam induced current images (EBIC) (as well as defect etches and transmission electron microscopy) show that 2800Å-thick, MBE Ge0.19Si0.81 on 70-μm-wide mesas have zerothreading and nearly zero misfit dislocations. The Ge0.19Si{0.81} grown on unpatterned, large areas is heavily dislocated. It is also evident from the images that heterogeneous nucleation of misfit dislocations is dominant in this composition range. 1000Å-thick, RTCVD Ge0.14Si0.86 films deposited on 70 μm-wide mesas are also nearly dislocation-free as shown by EBIC, whereas unpatterned areas are more heavily dislocated. Thus, despite the high growth temperatures, only heterogeneous nucleation of misfit dislocations occurs and patterning is still effective. Photoluminescence spectra from arrays of GeSi on Si mesas show that even when the interface dislocation density on the mesas is high, growth on small areas results in a lower dislocation density than growth on large areas. 相似文献
68.
Michel P. Tcheou André L.L. Miranda Lisandro Lovisolo Eduardo A.B. da Silva Marco A.M. Rodrigues Paulo S.R. Diniz 《Digital Signal Processing》2012,22(2):288-297
In this paper, we verify how far electric disturbance signals can be compressed without compromising the analysis of encoded fault records. A recently proposed compression algorithm, referred to as Damped Sinusoidal Matching Pursuit (DSMP) has the remarkable feature of obtaining both compact and physically interpretable representations. However, for fault analysis applications, one is primarily interested in how accurate can be the analysis performed on compressed signals, instead of evaluating mean-squared error figures. Unlike previous works in digital fault records compression, the performance of the DSMP compression method is evaluated using a protocol based on fault analysis procedures commonly performed by expert engineers. This protocol is applied for comparing the results obtained in the analysis of both uncompressed records and their compressed versions at different compression ratios. The results show that the DSMP is a reliable compression system since it achieves high compression ratios (6.4:1) without causing fault analysis misinterpretation. 相似文献
69.
Benjamin Gerard Harouna Souley Ali Michel Zasadzinski Mohamed Darouach 《International Journal of Control, Automation and Systems》2012,10(6):1086-1095
This paper deals with the H ?? filtering problem for a class of nonlinear systems. This class of nonlinear systems is composed of a bilinear part and of a lipschitzian one. The use of an unbiasedness condition for the bilinear part (called quasi unbiasedness condition) permits to parameterize the filter matrices through a single gain. Two LPV (Linear Parameter Varying) extensions of the bounded real lemma are used to solve the filtering problem. This approach reduces the conservatism inherent to the boundedness of the inputs. Then the filtering solution is expressed in terms of LMI (Linear Matrix Inequality) to be verified at the vertices of a polytope. A numerical example is finally given to illustrate our approach. 相似文献
70.
The microstructure and mechanical properties of modified and non-modified stir-cast commercial aluminium alloys A-S7G03 and A-S4G have been investigated. Stir casting of these alloys resulted in spherical and/or rosette shape primary -phase, and the eutectic silicon was broken into miniature needle morphology. This stir-cast structure slightly improved the mechanical properties in comparison to those of conventionally cast alloys, however the fracture of the stir-cast alloys revealed intergranular brittle fracture. The addition of 0.02% strontium, in the form of Al-5 mass% Sr master alloy, during stir casting modified the eutectic silicon into a very fine spheroidal morphology, while the -phase particle showed the same morphology as the stir-cast alloys. This novel structure resulted in significant improvement of mechanical properties. The elongation of the modified stir-cast alloys was five times greater than that of the non-modified one. A transgranular mode of fracture was observed for the modified stircast alloys, moreover smooth ripple and dimple patterns were observed reflecting the high ductility of the modified stir-cast alloys. 相似文献