Railway semaphore signal — One of the earliest forms of fixed railway signal is the semaphore. These signals display their different indications to train drivers by changing the angle of inclination of a pivoted arm . Semaphore signals were patented in the early 1840s by… … Wikipedia
Synthetic aperture radar — (SAR) is a form of radar in which the highly directional (and thus very large) rotating antenna used by conventional radar is replaced with many low directivity small stationary antenna positions scattered over some area near or around the target … Wikipedia
Flutter (electronics and communication) — In the field of electronics and communication, flutter is the rapid variation of signal parameters, such as amplitude, phase, and frequency. Examples of electronic flutter are:*Rapid variations in received signal levels, such as variations that… … Wikipedia
china — /chuy neuh/, n. 1. a translucent ceramic material, biscuit fired at a high temperature, its glaze fired at a low temperature. 2. any porcelain ware. 3. plates, cups, saucers, etc., collectively. 4. figurines made of porcelain or ceramic material … Universalium
China — /chuy neuh/, n. 1. People s Republic of, a country in E Asia. 1,221,591,778; 3,691,502 sq. mi. (9,560,990 sq. km). Cap.: Beijing. 2. Republic of. Also called Nationalist China. a republic consisting mainly of the island of Taiwan off the SE coast … Universalium
nervous system, human — ▪ anatomy Introduction system that conducts stimuli from sensory receptors to the brain and spinal cord and that conducts impulses back to other parts of the body. As with other higher vertebrates, the human nervous system has two main… … Universalium
ECONOMIC AFFAIRS — THE PRE MANDATE (LATE OTTOMAN) PERIOD Geography and Borders In September 1923 a new political entity was formally recognized by the international community. Palestine, or Ereẓ Israel as Jews have continued to refer to it for 2,000 years,… … Encyclopedia of Judaism
United States — a republic in the N Western Hemisphere comprising 48 conterminous states, the District of Columbia, and Alaska in North America, and Hawaii in the N Pacific. 267,954,767; conterminous United States, 3,022,387 sq. mi. (7,827,982 sq. km); with… … Universalium
Mexico — /mek si koh /, n. 1. a republic in S North America. 97,563,374; 761,530 sq. mi. (1,972,363 sq. km). Cap.: Mexico City. 2. a state in central Mexico. 6,245,000; 8268 sq. mi. (21,415 sq. km). Cap.: Toluca. 3. Gulf of, Mexican, Golfo de México /gawl … Universalium
technology, history of — Introduction the development over time of systematic techniques for making and doing things. The term technology, a combination of the Greek technē, “art, craft,” with logos, “word, speech,” meant in Greece a discourse on the arts, both… … Universalium
Radio — is the transmission of signals, by modulation of electromagnetic waves with frequencies below those of visible light.Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of… … Wikipedia