low periodicity
21Halley's Comet — For the video game, see Halley s Comet (video game). 1P/Halley (Halley s Comet) Halley s Comet on March 8, 1986 Discovery …
22Radio propagation — is a term used to explain how radio waves behave when they are transmitted, or are propagated from one point on the Earth to another. [ H. P. Westman et al, (ed), Reference Data for Radio Engineers, Fifth Edition , 1968, Howard W. Sams and Co.,… …
23Photonic crystal — The opal in this bracelet contains a natural periodic microstructure responsible for its iridescent color. It is essentially a natural photonic crystal, although it does not have a complete photonic band gap. Photonic crystals are periodic… …
24periodic law — /pear ee od ik, pear /, Chem. 1. the law that the properties of the elements are periodic functions of their atomic numbers. 2. Also called Mendeleev s law. (originally) the statement that the chemical and physical properties of the elements… …
25Mansonella perstans — Loa loa (right) and M. perstans (left) Scientific classification …
26Helium atom scattering — (HAS) is a surface analysis technique used in materials science. HAS provides information about the surface structure and lattice dynamics of a material by measuring the diffracted atoms from a monochromatic helium beam incident on the sample.… …
27Discrete Fourier transform — Fourier transforms Continuous Fourier transform Fourier series Discrete Fourier transform Discrete time Fourier transform Related transforms In mathematics, the discrete Fourier transform (DFT) is a specific kind of discrete transform, used in… …
28Discrete-time Fourier transform — In mathematics, the discrete time Fourier transform (DTFT) is one of the specific forms of Fourier analysis. As such, it transforms one function into another, which is called the frequency domain representation, or simply the DTFT , of the… …
29Galloping Gertie — This article is about the first Tacoma Narrows Bridge, which collapsed in 1940. For the article on the current bridge, see Tacoma Narrows Bridge. Infobox Bridge bridge name = Tacoma Narrows Bridge (Galloping Gertie) caption = The first Tacoma… …
30Milankovitch cycles — Past and future Milankovitch cycles. VSOP allows prediction of past and future orbital parameters with great accuracy. ε is obliquity (axial tilt). e is eccentricity. ϖ is longitude of perihelion. esin(ϖ) is the precession index, which together… …
