perturbing effect
11Nuclear magnetic resonance — This article is about the physical phenomenon. For its use as a method in spectroscopy, see Nuclear magnetic resonance spectroscopy. NMR redirects here. For other uses, see NMR (disambiguation). First 1 GHz NMR Spectrometer (1000 MHz,… …
12Astronomical seeing — Schematic diagram illustrating how optical wavefronts from a distant star may be perturbed by a layer of turbulent mixing in the atmosphere. The vertical scale of the wavefronts plotted is highly exaggerated. Astronomical seeing refers to the… …
13Normalized Difference Vegetation Index — Negative values of NDVI (values approaching 1) correspond to water. Values close to zero ( 0.1 to 0.1) generally correspond to barren areas of rock, sand, or snow. Lastly, low, positive values represent shrub and grassland (approximately 0.2 to 0 …
14Discovery of Neptune — New Berlin Observatory at Linden Street, where Neptune was discovered observationally. Neptune was mathematically predicted before it was directly observed. With a prediction by Urbain Le Verrier, telescopic observations confirming the existence… …
15Modulational instability — In the field of nonlinear optics, modulational instability is a phenomenon whereby deviations from an optical waveform are reinforced by nonlinearity, leading to the generation of spectral sidebands and the eventual breakup of the waveform into a …
16HEBREW LITERATURE, MODERN — definition and scope beginnings periodization …
17Newton's theorem of revolving orbits — Figure 1: An attractive force F(r) causes the blue planet to move on the cyan circle. The green planet moves three times faster and thus requires a stronger centripetal force, which is supplied by adding an attractive inverse cube force. The …
18Stimulated emission — In optics, stimulated emission is the process by which an electron, perturbed by a photon having the correct energy, may drop to a lower energy level resulting in the creation of another photon. The perturbing photon is seemingly unchanged in the …
19Perturbation theory (quantum mechanics) — In quantum mechanics, perturbation theory is a set of approximation schemes directly related to mathematical perturbation for describing a complicated quantum system in terms of a simpler one. The idea is to start with a simple system for which a …
20Philosophiæ Naturalis Principia Mathematica —   Title page of Principia , first edition (1687) Original title …
