A. Khelif

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Complete surgical excision of a primary spinal tumor without contamination of the surgical wound is not always possible, and adjuvant therapy by chemotherapy and/or radiation therapy is important to improve local and survival disease free. The efficacy of radiation therapy is limited above L2 because of the risk of radionecrosis of the spinal cord if one(More)
The propagation of acoustic waves in a phononic crystal slab consisting of piezoelectric inclusions placed periodically in an isotropic host material is analyzed. Numerical examples are obtained for a square lattice of quartz cylinders embedded in an epoxy matrix. It is found that several complete band gaps with a variable bandwidth exist for elastic waves(More)
It is shown that it is possible to obtain complete planar phononic bandgaps in square and hexagonal (honeycomb) lattice phononic crystals formed by etching a periodic array of circular holes in a thin silicon plate (or membrane). Also, better bandgap properties are obtained using the hexagonal lattice structure; and, with practical structure sizes, it is(More)
In this paper we study and design quasi-2D optomechanical crystals, waveguides, and resonant cavities formed from patterned slabs. Two-dimensional periodicity allows for in-plane pseudo-bandgaps in frequency where resonant optical and mechanical excitations localized to the slab are forbidden. By tailoring the unit cell geometry, we show that it is possible(More)
Control of sound in phononic band-gap structures promises novel control and guiding mechanisms. Designs in photonic systems were quickly matched in phononics, and rows of defects in phononic crystals were shown to guide sound waves effectively. The vast majority of work in such phononic guiding has been in the frequency domain, because of the importance of(More)
Sonic crystals consisting of three-dimensional arrays of units which exhibit localized resonances have been discovered recently. Here, it is shown that their two-dimensional counterparts behave in a similar manner. Particularly, it is observed that the transmittance spectra show very asymmetric peaks which are explained as a Fano-like interference(More)
The existence of phononic bandgaps is shown in a phononic crystal structure composed of a silicon plate with stubbed tungsten pillars. Using the finite element method for numerical simulations, the evolution of bandgap opening with varying design parameters is studied. Several bandgaps have been observed for different lattice symmetries. It has been shown(More)
Primary tumors of the vertebral column are rare: 20 per cent of all primary tumors of the spinal column. The distribution by type of tumor shows that the three most frequent primary tumors considered to be "radio and/or chemo resistant lesions" are the chordoma (15.5 to 24.5%), the chondrosarcoma (20%) and the giant cell tumor (10%). A second group with(More)
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