Broadly speaking: all the energy is not by conduction or convection, but directly across the space to the way it is called radiation.
Narrowly speaking: radiation can be divided into: 1. high-energy free radiation (commonly known as radiation), such as X-rays, α (Ava) rays, β (Beta) rays, γ (yuma) rays, etc., which is the so-called radiation. 2. lower-energy free radiation (commonly known as electromagnetic waves), such as microwave ovens, cell phones, radio stations, transformers, picture tubes, etc., emitted by the electromagnetic waves. When the free radiation is large, it can cause disease or death in human beings or organisms.
Lower energy free radiation, that is, electromagnetic radiation. According to the different vibration frequency can be divided into microwave, very high frequency, ultra-high frequency, FM wave, low frequency, very low frequency and other regions. Its effect on human physiology has been many reports publicized, especially electromagnetic radiation (MAGNETIC RADIATION referred to as EMR), has become the latest threat of modern human pathology. In places where there is current through, high voltage power lines, radio, radar stations, etc. are extremely high radiation, according to foreign research reports pointed out that: breakthrough (pulsating wave) and uneven electro-optical welding will produce a sudden wave (pulsating wave) and uneven waves of electromagnetic radiation, which is why the female computer operator's pregnancy and miscarriage of accidents and welding work sexual function abnormality ratio bazaar reasons.