2. Characterized by complexity: Jeremy studied high math in school.
3. A reference to unexpected and steep expenses for one's living standards: The high cost of living is getting more challenging.
4. Descriptive of excessive, often exuberant, or inappropriate behavior: Todd appeared to be high on drugs as indicated by his inappropriate laughter.
Jesse called out "Hi!" to his friend when he saw him hie quickly across the high fence on his way home from school.
2. Heating with radio-frequency current that is produced by an electron-tube oscillator or an equivalent radio-frequency power source.
3. A method of heating a material by inducing a high-frequency current into it or having the material act as the dielectric (having little or no ability to conduct electricity) between two plates charged with a high-frequency current.
2. A separation of finely pulverized materials by placing them in electrostatic separators.
They typically can be read from less than three feet away and transmit data faster than low-frequency tags, but they consume more power than low-frequency tags.
The frequency used in library RFID systems is 13.56 MHz. ISO 18000-3 addresses the air interface for tags operating in this frequency range.
These tags can be read at up to a distance of ten feet and have a fast data transfer rate.
Electrophoresis is the motion of charged particles in a colloid (mixture in which one substance is divided into minute particles, called colloidal particles, and dispersed throughout a second substance) under the influence of an electric field. Particles with a positive charge go to the cathode and negative charge to the anode.
Although they are generally unfamiliar, the rare-earth elements are essential for many hundreds of applications.
The versatility and specificity of the rare-earth elements have given them a level of technological, environmental, and economic importance considerably greater than might have been expected from their relative obscurity.
As technological applications of rare-earth elements have multiplied over the past several decades, demand for several of the less abundant (and formerly quite obscure) REE has increased dramatically.
Some of the Applications of the Rare-Earth Elements
- Color cathode-ray tubes and liquid-crystal displays used in computer monitors and televisions employ europium as the red phosphor and no substitute is currently known.
- Fiber-optic telecommunication cables provide much greater bandwidth than the copper wires and cables they have largely replaced.
- Fiber-optic cables can transmit signals over long distances because they incorporate periodically spaced lengths of erbium-doped fiber that function as laser amplifiers because it alone possesses the required optical properties.
- Permanent magnet technology has been revolutionized by alloys containing neodymium, samarium, gadolinium, dysprosium, or praseodymium.
- Small, lightweight, high-strength rare-earth element magnets have allowed miniaturization of numerous electrical and electronic components used in appliances, audio and video equipment, computers, automobiles, communications systems, and military gear.
- Several rare-earth elements are essential constituents of both petroleum fluid cracking catalysts and automotive pollution-control catalytic converters.
- Although more expensive, lanthanum-nickel-hydride batteries offer greater energy density, better charge-discharge characteristics, and fewer environmental problems when they are recycled or disposed of.
- The rare earth elements are essential for a diverse and expanding array of high-technology applications, which constitute an important part of the industrial economy of the United States.
- Long-term shortages or unavailability of rare-earth elements would force significant changes in many technological aspects of American life.
- State-run Chinese firms sharply expanded production and slashed prices of rare earths in the 1990's, forcing producers in the United States (previously the world’s leading producer and exporter) and elsewhere out of the market which no doubt will change now that China has restricted its exports of rare-earth minerals.
They can send information faster and farther than high-frequency and low-frequency tags, but radio waves don’t pass through items with high water content; such as, fruit, at these frequencies.
UHF tags are also more expensive than low-frequency tags, and they use more power.