High harmonic generation in solids presents the possibility for bringing attosecond techniques to semiconductors and a simple source for frequency comb spectroscopy in the vacuum ultraviolet. We generate up to the seventh harmonic of a Tm fiber laser by focusing in silicon or zinc oxide. The harmonics are strong and stable, with no indication of material damage. Calculations show the potential ...

We briefly introduce the source and harm of aircraft grid harmonic and summarise the common methods of harmonic reduction, such as passive filter, multi-pulse rectifier, power factor correction and active power filter. Then we introduce the disadvantages of the above methods, analyse the application status, advantages and deficiencies of active power filter in aircraft grid harmonic reduction, ...

in this paper, computer simulation of a three-phase synchronous motor drive is described. this drive/system is supplied with a new type of pulse-width modulated voltage source inverter (pwm vsi) whose amplitude of the first harmonic, compared to a conventional sinusoidal pwm vsi, is increased by about 17% and whose amplitude of higher harmonics is also reduced inversely proportional to their or...

Pure-tone song is a common and widespread phenomenon in birds. The mechanistic origin of this type of phonation has been the subject of long-standing discussion. Currently, there are three hypotheses. (i) A vibrating valve in the avian vocal organ, the syrinx, generates a multifrequency harmonic source sound, which is filtered to a pure tone by a vocal tract filter ("source-filter" model, analo...

For a given high-speed machinery, a significant source of the internally induced vibrational excitation is the presence of high frequency harmonics in the trajectories that the system is forced to follow. In this paper a special class of rational Brzier curves is presented that correspond to low-harmonic trajectory patterns. Harmonic Bernstein polynomials and harmonic deCasteljau algorithm are ...

This paper used the gradient blind signal separation algorithm to carry out the electrical power system harmonic signal analysis through the simulation experiment. The experiment result proved that the electrical power system harmonic signal separation based on the gradient algorithm is accurate. Through comparing the separation performance by using the different step size, the adaptive changin...

Extreme ultraviolet (XUV) single-order high harmonic pulses with 10(6) photons/pulse were separated from multiple harmonic orders by a time-compensated toroidal-grating monochromator consisting of a pair of toroidal gratings. The first grating separates the harmonic order and the second one compensates for the pulse-front tilt. The center photon energies were tunable between 42 and 23 eV. The s...

–With the widespread use of harmonic generating devices, the control of harmonic currents to maintain a high level of power quality is becoming increasingly important. An effective way for harmonic suppression is the harmonic compensation by using active power filter. This paper presents a comprehensive survey of DSTATCOM control strategies put forward recently. It is aimed at providing a broad...

Power quality standards (IEEE-519) require to limit the total harmonic distortion within satisfactory range caused by power electronic based devices. Our work deals with the design of hybrid active filter to reduce current perturbations produced by power electronics based devices. The Instantaneous Active and Reactive Power Method (pq) is used to perform the identification of disturbing current...

A room-temperature Schottky diode-based WM-86 (WR-0.34) harmonic mixer was developed to build high-resolution spectrometers, and multipixel receivers in the terahertz (THz) region for applications such as radio astronomy, plasma diagnostics, and remote sensing. The mixer consists of a quartz-based local oscillator (LO), intermediate-frequency (IF) circuits, and a GaAs-based beam-lead THz circui...