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331.
Hans G. Feichtinger José C. Príncipe José Luis Romero Alexander Singh Alvarado Gino Angelo Velasco 《Advances in Computational Mathematics》2012,36(1):67-78
In this paper we study the reconstruction of a bandlimited signal from samples generated by the integrate and fire model. This sampler allows us to trade complexity in the reconstruction algorithms for simple hardware implementations, and is specially convenient in situations where the sampling device is limited in terms of power, area and bandwidth. Although perfect reconstruction for this sampler is impossible, we give a general approximate reconstruction procedure and bound the corresponding error. We also show the performance of the proposed algorithm through numerical simulations. 相似文献
332.
Przemek J. Bock Pavel Cheben Aitor V. Velasco Jens H. Schmid Andr Delge Mirosaw Florjaczyk Jean Lapointe Dan‐Xia Xu Martin Vachon Siegfried Janz María L. Calvo 《Laser \u0026amp; Photonics Reviews》2013,7(6):L67-L70
A planar waveguide Fourier‐transform spectrometer with densely arrayed Mach‐Zehnder interferometers is demonstrated. Subwavelength gratings are used to produce an optical path difference without waveguide bends. The fabricated device comprises of an array of 32 Mach‐Zehnder interferometers, which produce a spatial interferogram without any moving parts, yielding a spectral resolution of 50 pm and a free‐spectral range of 0.78 nm. As a result of similar propagation losses in subwavelength grating waveguides and conventional strip waveguides, loss imbalance is minimized and high interferometic extinction ratio of −25 to −30 dB is obtained. Furthermore, phase and amplitude errors arising from normal fabrication variation are compensated by the spectral retrieval process using calibration measurements. 相似文献
333.
Laura Rubio-Pérez Pankaj Sharma F. Javier Pérez-Flores Luis Velasco J. Luis. Arias Armando Cabrera 《Tetrahedron》2012,68(10):2342-2348
A one-pot stibine modified Co2(CO)8 homogeneous catalytic reductive N-alkylation of primary amides using aldehydes/ketones as alkylating agents, is reported. Good to excellent yields of a wide range of secondary amides are obtained (up to 97%) under relative mild conditions. 相似文献
334.
Velasco E Navascués G Mederos L 《Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics》1999,60(3):3158-3164
Using a first-order perturbation theory, we have studied the phase diagram of a binary mixture of hard spheres for different values of the size ratio. Recent models for the two-body depletion potential between large spheres are used to take into account the role of the small spheres. The theory predicts a complex phase diagram including a fluid-solid transition at high packing fraction of small spheres, metastability of fluid-fluid demixing, an isostructural solid-solid transition at high packing fraction of the large spheres for sufficiently small values of the size ratio q of the spheres, and the tendency to sticky-sphere behavior in the limit q-->0. The agreement with recent simulation results is quite good. We also show that this phenomenology was already implicit in the pioneering work of Asakura and Oosawa. 相似文献
335.