| 单词 | ultraviolet |
| 释义 | ultraviolet (once / 11611 pages) adjn Use the adjective ultraviolet to describe light with a wavelength that's less than visible light, but longer than x-rays. You can't see ultraviolet light. You might hear people talk about ultraviolet light as UV radiation — it's the part of sunlight that can give you a sunburn if you're exposed to it for too long. In physics, this kind of electromagnetic radiation is defined by how long its waves are. The word itself, ultraviolet, refers to the fact that its wavelength is shorter than the violet end of the spectrum of visible light. The Latin prefix ultra means "beyond." WORD FAMILYultraviolet USAGE EXAMPLESPhototherapy, which uses ultraviolet light to tame inflammation, is an option, too. Washington Post(Dec 30, 2016) Atomic clocks use ultraviolet signals emitted in the change of electron energy levels to tell the time. BBC(Dec 30, 2016) Researchers at CERN, the European particle physics laboratory outside Geneva, trained an ultraviolet laser on antihydrogen, the antimatter counterpart of hydrogen. Nature(Dec 18, 2016) 1adj having or employing wavelengths shorter than light but longer than X-rays; lying outside the visible spectrum at its violet end ultraviolet radiation an ultraviolet lamp Syn invisible, unseeable impossible or nearly impossible to see; imperceptible by the eye 2n radiation lying in the ultraviolet range; wave lengths shorter than light but longer than X rays Syn|Hypo|Hyper UV, ultraviolet illumination, ultraviolet light, ultraviolet radiation sun-ray, sunray a ray of artificial ultraviolet light from a sunray lamp actinic radiation, actinic ray electromagnetic radiation that can produce photochemical reactions |
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