âIdealâ means that the feed has symmetrical properties and each port has an axial ratio of 0 dB, so each port responds only to signals with the appropriate sense of polarization and signals with the opposite sense are infinitely attenuated. The feed is mounted at the dishâs focal point.
Leizu(å«ç¥) was a legendary Chinese empress and wife of the Yellow Emperor. According to tradition, she discovered silk and invented the silk loom in the 27th century BC.Leizu discovered silkworms while on a walk investigating damage to the emperor's mulberry trees.However there are different accounts of exactly how she discovered that silkworms made silk. One account says that she used her finger to touch a piece of the silk worm causing a strand of silk come out.eizu discovered silkworms while on a walk investigating damage to the emperor's mulberry trees. However there are different accounts of exactly how she discovered that silkworms made silk. One account says that she used her finger to touch a piece of the silk worm causing a strand of silk come out.
Foreign customers also call silk the headspring of beauty, for products made of it are rather flowery. China is the earliest country raising silkworms and weaving silk. It is said the silkworm was first raised by Lei Zu, wife of the Yellow Emperor. According to archaeological speculation, the Chinese have begun to raise silkworms, and pull and weave silk since the middle Neolithic Period 5000-6000 years ago.