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What is electromagnetism radiate? How to reduce radiation hazard?

From;  Author:Stand originally

The alternant change of electric field and magnetic field generates electromagnetic wave. Electromagnetic wave blasts off to the middle of sky or the phenomenon of leak calls electromagnetism radiation. The electromagnetism radiate of excessive caused electromagnetism pollution.

1.Common electromagnetism radiate cause
Generally speaking, all sorts of radar system, TV and equipment of radio frequency induction and broadcasting emissive system, dielectric heating, radio frequency and equipment of microwave medical treatment, report machine launcher of equipment, communication power station of station of communication of earth of station, satellite, large power, be defeated change electric equipment, high pressure and extrahigh voltage transmit electricity.

Of area of field of 2. electromagnetism radiate differentiate
General component is area of electromagnetism radiate field remote region field and close area field.

(Field of 1) close area reachs a characteristic
It is a center with field source, in the area inside limits of a wavelengh, call close area field normally, also can call inductive field. Close area field has following characteristics normally:
Inside close area field, the size of electric field intensity and magnetic field intensity concerns without certain proportion. Namely: E#1377H. Usually, the field cause with tall to voltage little electric current (if launch the) such as line of aerial, make a present of, electric field should be gotten more by force than magnetic field much, big to electric depress electric current field source (the mould) that is like certain induction heating installation, magnetic field should be gotten greatly than electric field much.
The electromagnetism field intensity of close area field is gotten greatly than remote region field much. Say from this angle, the key that electromagnetism defends should be in close area field. The change that the electromagnetism field intensity of close area field follows a distance is sharper, inside this space inhomogenous degree bigger.

(Field of 2) remote region reachs a characteristic
In it is a center with field source, radius calls remote region field for the dimensional limits besides a wavelengh, also can call radiation field. The main characteristic of remote region field is as follows:
In remote region field, all electromagnetism energy all basically travel with radiate of electromagnetic wave form, the attenuation of intensity of radiate of this kind of field should compare inductive field to be gotten slow much.
In remote region field, electric field intensity and magnetic field intensity are like next relations: In international system of unit, e=377H, the moving direction of electric field and magnetic field is mutual and perpendicular, perpendicular the transmission way at electromagnetic wave. Remote region field is weak field, intensity of its electromagnetism field all lesser.

(The meaning that field of 3) close area and remote region field differentiate
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