单词	D-layer
释义	D-layer /ˈdiːleɪə / noun The lowest layer of the ionosphere, able to reflect low-frequency radio waves.They will penetrate to the D-layer and increase the ionisation process and the electron density.... The ionospheric D-layer is a narrow bandwidth radar target often with a very small scattering cross section. Simply due to the height difference of the ‘responsible’ layer, troposcatter is useful up to distances of 700 Km, whereas D-layer is at best in the 600/1300 Km range. Origin 1930s: from an arbitrary use of the letter D.
随便看	alder tree alderwoman alder wood al desko aldicarb Aldine Aldis lamp Aldis lens Aldiss, Brian Aldis sight aldohexose aldoketen aldoketene aldol aldolase aldol condensation aldolisation aldolization aldol reaction aldonic acid aldopentose aldordom aldose aldosterone aldosteronism

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