宇宙微波背景辐射是微波的天然来源。研究辐射以帮助科学家了解宇宙大爆炸。包括太阳在内的恒星是天然的微波源。在适当的条件下,原子和分子可以发射微波。人造微波源包括微波炉,脉冲电路,电路,通信传输塔和雷达。可以使用固态装置或特殊真空管来产生微波。固态器件的例子包括激光器(基本上是光在微波范围内的激光器),耿氏二极管,场效应晶体管和IMPATT二极管。真空管发生器使用电磁场以密度调制模式引导电子,其中电子组通过器件而不是流。这些装置包括速调管,回旋管和磁控管。微波辐射被称为“辐射”,因为它向外辐射而不是因为它本质上是放射性的或电离的。不知道低水平的微波辐射会产生不利的健康影响。然而,一些研究表明长期接触可能会起到致癌作用。微波暴露可引起白内障,因为经纬度加热使眼睛晶状体中的蛋白质变性,使其变成乳白色。虽然所有组织都易受加热,但眼睛特别脆弱,因为它没有血管来调节温度。微波辐射与微波听觉效应有关,其中微波曝光产生嗡嗡声和咔嗒声。这是由内耳内的热膨胀引起的。微波灼伤可以发生在更深的组织中,而不仅仅是在表面上,因为微波更容易被含有大量水的组织吸收。然而,较低的暴露水平会产生热量而不会烧伤。该效果可用于各种目的。美国军方使用毫米波来击退目标人员的不适热量。另一个例子是,1955年,James Lovelock使用微波透热法复活了冷冻大鼠。 Andjus,R.K。; Lovelock,J.E。(1955)。 “通过微波透热法将体温从0到1°C恢复到大鼠体内”。生理学杂志。 128(3):541-546。

澳洲迪肯大学物理学Essay代写:微波辐射

Cosmic microwave background radiation is a natural source of microwaves. The radiation is studied to help scientists understand the Big Bang. Stars, including the Sun, are natural microwave sources. Under the right conditions, atoms and molecules can emit microwaves. Man-made sources of microwaves include microwave ovens, masers, circuits, communication transmission towers, and radar. Either solid state devices or special vacuum tubes may be used to produce microwaves. Examples of solid state devices include masers (essentially lasers where the light is in the microwave range), Gunn diodes, field-effect transistors, and IMPATT diodes. The vacuum tube generators use electromagnetic fields to direct electrons in a density-modulated mode, where groups of electrons pass through the device rather than a stream. These devices include the klystron, gyrotron, and magnetron. Microwave radiation is called “radiation” because it radiates outward and not because it’s either radioactive or ionizing in nature. Low levels of microwave radiation are not known to produce adverse health effects. However, some studies indicate long-term exposure may act as a carcinogen. Microwave exposure can cause cataracts, as dielectic heating denatures proteins in the eye’s lens, turning it milky. While all tissues are susceptible to heating, the eye is particularly vulnerable because it doesn’t have blood vessels to modulate temperature. Microwave radiation is associated with the microwave auditory effect, in which microwave exposure produces buzzing sounds and clicks. This is caused by thermal expansion within the inner ear. Microwave burns can occur in deeper tissue, not just on the surface, because microwaves are more readily absorbed by tissue that contains a lot of water. However, lower levels of exposure produce heat without burns. This effect may be used for a variety of purposes. The United States military uses millimeter waves to repel targeted persons with uncomfortable heat. As another example, in 1955, James Lovelock reanimated frozen rats using microwave diathermy. Andjus, R.K.; Lovelock, J.E. (1955). “Reanimation of rats from body temperatures between 0 and 1 °C by microwave diathermy”. The Journal of Physiology. 128 (3): 541–546.

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