Spherical harmonics are employed in a wide range of applications in computational science and physics, and many of them require the rotation of functions. We present an efficient and accurate algorithm for the rotation of finite spherical harmonics expansions. Exploiting the pointwise action of the rotation group on functions on the sphere, we obtain the spherical harmonics expansion of a rotat...

This paper proposes a three-level discrete Fourier transform (DFT) method to provide an accurate estimate of power system frequency in real time. The first level decomposes a power system signal into two orthogonal cosineand sine-filtered signals. The second and third levels are used to determine the amplitude ratio of the cosineand sine-filtered signals without encountering the zero-crossing p...

Long-wavelength lasers have great potential to become a new-generation drive laser for tabletop coherent light sources in the soft X-ray region. Because of the significantly low conversion efficiency from a long-wavelength light field to high-order harmonics, their pulse characterization has been carried out by measuring the carrier-envelope phase and/or spatial dependences of high harmonic spe...

Author(s) of this paper may load this reprint on their own web site provided that this cover page is retained. Republication of this article or its storage in electronic databases or the like is not permitted without prior permission in writing from the IUCr. A numerically efficient method of constructing symmetric real spherical harmonics is presented. Symmetric spherical harmonics are real sp...

The simple Selective Harmonic Elimination (SHE) for 3-Phase Voltage Source Inverter (VSI) is presented here. The proposed work is to examine the Selective Harmonic Elimination (SHE) and to eliminate harmonics produced by Pulse Width Modulation (PWM) inverter. The selective harmonic elimination method for three phase Voltage Source Inverter (VSI) is generally based on ideas of opposite harmonic ...

We use a carrier-envelope-phase stabilized sub-2-cycle laser pulse to generate high-order harmonics and study how the two-dimensional spectrum of harmonics, with the resolutions in temporal frequency and spatial frequency, is shaped by the laser phase. An arrowlike spectrum obtained experimentally when the gas cell is located in front of the laser focus point shows a resolution of full quantum ...

Generation of high harmonics is the only available way to obtain coherent extreme ultraviolet (EUV) and soft X-ray radiation in laboratory conditions. We present a system for high harmonics generation and study of its parameters. Capillary waveguide filled with Ar gas is used to convert the pumping laser radiation from a Ti:Sapphire mode-locked femtosecond laser system. In the capillary the las...

0142-0615/$ see front matter 2012 Elsevier Ltd. A http://dx.doi.org/10.1016/j.ijepes.2012.08.024 ⇑ Corresponding author. Tel./fax: +90 312 212 13 3 E-mail address: [email protected] (I. Colak). In this study, an enhanced SPWM modulation scheme is developed in order to minimize total harmonic ratio (THD) by eliminating the side band harmonics that are not paid attention in regular modulation sc...

In his classic work on radiative transfer, Chandrasekhar introduced the discrete ordinates method for solving the integro-di erential equation of radiative transfer; the spherical harmonics method is a spectral analog of this method. Not surprisingly, there is a close connection between the spherical harmonics and discrete ordinates methods. The spherical harmonics method raises some interestin...

Spectral weighting functions were estimated in a pitch-comparison task to assess the relative influence of individual harmonics on listeners' pitch judgment. The stimuli were quasi-harmonic complex tones composed of the first 12 components, with fundamental frequencies ranging from 100 to 800 Hz. On each stimulus presentation the frequency of each harmonic was randomly jittered by a small amoun...