نتایج جستجو برای: forward directivity pulse

تعداد نتایج: 209168  

2015
Brent Reichman Micah Downing Allan Aubert Richard L. McKinley Tracianne B. Neilsen Alan T. Wall Michael M. James

Measurements of the sound field near an F-35B during vertical landing operations are reported. Data are presented and discussed from the approach, hover, and descent of the aircraft, and compared with ground run-up measurements. Overall levels are comparable to published values for the F-35A at 50% engine thrust ratio during ground run-ups. Onethird-octave spectra are also presented, and spectr...

Journal: :Optics letters 2009
Yaroslav V Kartashov Victor A Vysloukh Lluis Torner

We put forward what we believe to be a novel strategy to achieve synthetic nonlinearities where local and nonlocal contributions compete on a similar footing, thus yielding intermediate tunable responses ranging from local to strongly nonlocal. The setting addressed is a semiconductor material with both Kerr and thermal nonlinearities illuminated by a pulse train with suitable pulse width and r...

2002
C. B. Schroeder W. P. Leemans

Raman forward scattering of a high-intensity, short-duration, frequency-chirped laser pulse propagating in an underdense plasma is examined. The growth of the direct forward scattered light is calculated for a laser pulse with a linear frequency chirp in various spatiotemporal regimes. This includes a previously undescribed regime of strongly-coupled four-wave nonresonant interaction, which is ...

Journal: :Hypertension 2011
Junichiro Hashimoto Sadayoshi Ito

A significant link has been reported between aortic stiffening and renal microvascular damage, but the underlying mechanism remains poorly understood. We hypothesized that alterations in central and renal hemodynamics are responsible for this link. In 133 patients with hypertension, pressure waveforms were recorded on the radial, carotid, femoral, and dorsalis pedis arteries with applanation to...

2017
Mikael Dich

The derivation of a formula for accurate estimation of the total radiated power from a transmitting antenna for which the radiated power density is known in a finite number of points on the far-field sphere is presented. The main application of the formula is determination of directivity from power-pattern measurements. The derivation is based on the theory of spherical wave expansion of electr...

2009
Alana E. Kirby John C. Middlebrooks John Middlebrooks

26 Cochlear implants stimulate the auditory nerve with amplitude-modulated electric pulse 27 trains. Pulse rates >2000 pulses per second (pps) have been hypothesized to enhance 28 transmission of temporal information. Recent studies, however, have shown that higher 29 pulse rates impair phase locking to sinusoidal amplitude modulation in the auditory 30 cortex and impair perceptual modulation d...

Journal: :Optics express 2012
Guanghao Rui Weibin Chen Don C Abeysinghe Robert L Nelson Qiwen Zhan

Coupling nanoscale emitters via optical antennas enables comprehensive control of photon emission in terms of intensity, directivity and polarization. In this work we report highly directional emission of circularly polarized photons from quantum dots coupled to a spiral optical antenna. The structural chirality of the spiral antenna imprints spin state to the emitted photons. Experimental resu...

2016
Saad Hassan Kiani Khalid Mahmood Sharyar Shafeeq Khalil Muhammad Khan

In advance communication technology, patch antennas are widely exploit due to their inexpensive and light weighted structure. This paper presents a novel design of miniaturized multiband patch antenna using different substrates frequently used in patch antennas. Various substrates such as Teflon, Roger 5880, Bakelite and Air are in use to achieve better gain and directivity. The proposed miniat...

2006
I. S. Misra R. S. Chakrabarty B. B. Mangaraj J. H. Wang

This paper presents an optimum design technique of an asymmetric V-dipole antenna and it’s a three-element Yagi-Uda array using Genetic Algorithm (GA). The optimization parameter for the V-dipole is the directivity and that for the Yagi-Uda array are the input impedance and directivity. The theoretical analysis has been done using a Moment-Method technique in a very simple step-by-step way, and...

2015
Wen-Kung Tseng

In general the audible sound has the characteristics of spreading, however the ultrasound is directional. This study used amplitude-modulating technique for an array of 8 ultrasonic transducers to produce directional audible sound beam. In this study sound field distribution for the directional audible sound beam has been investigated. The effect of different weightings varied with different fr...

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