| 释义 |
ultraviolet
ul·tra·vi·o·let U0013200 (ŭl′trə-vī′ə-lĭt)adj. Abbr. UV1. Of or relating to electromagnetic radiation between violet visible light and x-rays in the electromagnetic spectrum, having frequencies between 790 terahertz and 30 petahertz and wavelengths between 380 nanometers and 10 nanometers. 2. Of or relating to a light bulb that emits ultraviolet radiation.n. The ultraviolet range of electromagnetic radiation: Sunburns result from radiation in the ultraviolet.ultraviolet (ˌʌltrəˈvaɪəlɪt) n (General Physics) the part of the electromagnetic spectrum with wavelengths shorter than light but longer than X-rays; in the range 0.4 × 10–6 and 1 × 10–8 metresadj (General Physics) of, relating to, or consisting of radiation lying in the ultraviolet: ultraviolet radiation. Abbreviation: UV ul•tra•vi•o•let (ˌʌl trəˈvaɪ ə lɪt)
adj. 1. pertaining to electromagnetic radiation having wavelengths in the range of approximately 5–400 nm, shorter than visible light but longer than x-rays. 2. pertaining to, producing, or using light having such wavelengths: an ultraviolet lamp. Compare infrared. n. 3. ultraviolet radiation. [1870–75] ul·tra·vi·o·let (ŭl′trə-vī′ə-lĭt)Adjective Relating to electromagnetic radiation having wavelengths shorter than those of visible light but longer than those of x-rays. See more at electromagnetic spectrum.Noun Ultraviolet light or the ultraviolet part of the spectrum. See Note at infrared.Thesaurus| Noun | 1. |  ultraviolet - radiation lying in the ultraviolet range; wave lengths shorter than light but longer than X raysultraviolet illumination, ultraviolet light, ultraviolet radiation, UVactinic radiation, actinic ray - electromagnetic radiation that can produce photochemical reactionssun-ray, sunray - a ray of artificial ultraviolet light from a sunray lamp | | Adj. | 1. |  ultraviolet - 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"invisible, unseeable - impossible or nearly impossible to see; imperceptible by the eye; "the invisible man"; "invisible rays"; "an invisible hinge"; "invisible mending" |
Translationsultraviolet (altrəˈvaiəlit) adjective (of light) consisting of rays from the invisible part of the spectrum beyond the purple, that have an effect on the skin, eg causing suntan. 紫外線的 紫外线的ultraviolet
ultraviolet the part of the electromagnetic spectrum with wavelengths shorter than light but longer than X-rays; in the range 0.4 × 10--6 and 1 × 10--8 metres ultraviolet[¦əl·trə′vī·lət] (physics) Pertaining to ultraviolet radiation. Abbreviated UV. UltraViolet(1) See ultraviolet light.
(2) A cloud-based storage locker for licensed content from the Digital Entertainment Content Ecosystem (see DECE). Under the Digital HD brand, purchases of Blu-ray discs with redeemable coupons and purchases of movies and TV shows (not rental) from participating online retailers entitles users to keep their content in the UltraViolet cloud and stream or download it as required.
Depending on the retailer's agreement, content might be sharable with friends and family, and parental access can be applied. A physical disc may also be obtainable. See Digital HD, Blu-ray Combo Pack and media locker.ultraviolet
ultraviolet [ul″trah-vi´o-let] denoting electromagnetic radiation of wavelength shorter than that of the violet end of the spectrum, having wavelengths of 4–400 nanometers.ultraviolet A (UVA) radiation" >ultraviolet radiation with wavelengths between 320 and 400 nm, comprising over 99 per cent of such radiation that reaches the surface of the earth. Ultraviolet A enhances the harmful effects of ultraviolet B radiation and is also responsible for some photosensitivity reactions; it is used therapeutically in the treatment of a variety of skin disorders.ultraviolet B (UVB) radiation" >ultraviolet radiation with wavelengths between 290 and 320 nm, comprising less than 1 per cent of the ultraviolet radiation that reaches the earth's surface. Ultraviolet B causes sunburn and a number of damaging photochemical changes within cells, including damage to DNA, leading to premature aging of the skin, premalignant and malignant changes, and a variety of photosensitivity reactions; it is also used therapeutically for treatment of skin disorders.ultraviolet C (UVC) radiation" >ultraviolet radiation with wavelengths between 200 and 290 nm; all of this type of radiation is filtered out by the ozone layer so that none reaches the earth's surface. Ultraviolet C is germicidal and is also used in ultraviolet phototherapy.ultraviolet rays electromagnetic radiation beyond the violet end of the visible spectrum; they are not visible to humans. They are produced by the sun but are absorbed to a large extent by particles of dust and smoke in the earth's atmosphere. They are also produced by the so-called sun lamps. They can produce sunburn and affect skin pigmentation, causing tanning. When they strike the skin surface they transform provitamin D, secreted by the glands of the skin, into vitamin D, which is then absorbed into the body. Because ultraviolet rays are capable of killing bacteria and other microorganisms, they are sometimes used to sterilize objects in specially designed cabinets, or to sterilize the air in operating rooms and other areas where destruction of bacteria is necessary.ultraviolet therapy the employment of radiation" >ultraviolet radiation in the treatment of diseases, particularly those affecting the skin. See also therapy" >PUVA therapy and photochemotherapy. Among the diseases that respond to this form of therapy are acne vulgaris, psoriasis, and external ulcers" >ulcers.
Dosage. The dosage unit of ultraviolet radiation is expressed as minimal dose" >erythema dose (MED). Because of varying degrees of skin thickness and pigmentation, human skin varies widely in its sensitivity to ultraviolet radiation. The MED refers to the amount of radiation that will produce, within a few hours, minimal erythema" >erythema (redness caused by engorgement of capillaries) in the average Caucasian skin. Dosage for individual patients is prescribed according to probable sensitivity as determined by that individual's skin type as compared to average sensitivity.Degrees of Erythema. Minimal erythema is a first degree erythema and usually is produced after about 15 seconds of exposure to a high-pressure mercury arc in a quartz burner placed at a distance of 75 cm (30 in) from the skin. A second degree erythema results from a dose of about 2.5 MED; its effects become apparent about 4 to 6 hours after application and are followed by slight peeling of the skin. A third degree erythema is produced by about 5 MED; it may become apparent within 2 hours after application and is accompanied by edema followed by marked desquamation. A fourth degree erythema is produced by about 10 MED and is characterized by blistering.Precautions. Ultraviolet therapy is safe only in the hands of a skilled and knowledgeable therapist. Areas of “thin skin” that may be burned more readily than that receiving treatment must be protected by wet towels or dressings. The eye is highly sensitive to ultraviolet radiation; therefore some form of protection, such as goggles, compresses, or cotton balls, should be provided for both the patient and the therapist to avoid damage to the conjunctiva and cornea.
Certain drugs, such as the sulfonamides, greatly increase sensitivity to ultraviolet radiation. All patients scheduled for this form of therapy should be questioned in regard to the medication they are taking so the dosage can be adjusted accordingly or the treatment deferred.ul·tra·vi·o·let (UV, uv), (ŭl'tră-vī'ō-let), Denoting electromagnetic rays at higher frequency than the violet end of the visible spectrum.ul·tra·vi·o·let (ŭl'tră-vī'ŏ-lĕt) Denoting electromagnetic rays at higher frequency than the violet end of the visible spectrum. ultraviolet (UV) Radiant energy of wavelengths smaller than those of the violet end of the visible spectrum and longer than about 1 nm. The wave band comprising radiations between 315 and 380 nm is referred to as UV-A. Excessive exposure to these radiations can cause cataract. The wave band comprising radiations between 280 and 315 nm is referred to as UV-B. Excessive exposure to all these radiations can cause photokeratitis and corneal opacity, while radiations between 295 and 315 nm can cause cataract. The wave band comprising radiations between 200 and 280 nm is referred to as UV-C. Excessive exposure to these radiations can cause photokeratitis and corneal opacity. See blepharospasm; actinic keratoconjunctivitis; excimer laser; absorptive lens; nanometre; pinguecula; wavelength.
| Table U1 Divisions of the ultraviolet spectrum | | UV-A (near) | 380-315 nm | | UV-B (middle) | 315-280 nm | | UV-C (far) | 280-200 nm |
See UV
See UVultraviolet
Related to ultraviolet: Ultraviolet spectroscopy, Ultraviolet RaysSynonyms for ultravioletnoun radiation lying in the ultraviolet rangeSynonyms- ultraviolet illumination
- ultraviolet light
- ultraviolet radiation
- UV
Related Words- actinic radiation
- actinic ray
- sun-ray
- sunray
adj having or employing wavelengths shorter than light but longer than X-raysRelated Words |