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In semiconductors , the major-use compound is gallium arsenide used in microwave circuitry and infrared applications. Gallium nitride and indium gallium nitride , minority semiconductor uses, produce blue and violet light-emitting diodes (LEDs) and diode lasers . Semiconductor use is

3 Natural abundance 3 Production 4 Applications 4.1 Optics 4.2 Electronics 4.2.1 Gallium arsenide germanium solar cell 4.3 Other uses 4.4 Dietary supplements 5 Precautions 6 See also 7 Footnotes 8 References 9 External links [ edit ] History See also

Electronic devices have a wide range of failure modes . These can be distinguished by their development in time (sudden failure or gradual degradation), by environmental effects (e.g. corrosion , ionizing radiation ) or by the electrical parameter which was exceeded (e.g. electrostatic discharge

If the biologically active molecule chosen for PET is FDG , an analogue of glucose , the concentrations of tracer imaged then give tissue metabolic activity, in terms of regional glucose uptake. Although use of this tracer results in the most common type of PET scan, other tracer molecules

Plutonium is the heaviest naturally occurring or primordial element . The most stable isotope of plutonium is plutonium-244 , with a half-life of about 80 million years, long enough to be found in trace quantities in nature. [ 3 ] The most important isotope of plutonium is plutonium-239

A bivalent element, beryllium is found naturally only combined with other elements in minerals. Notable gemstones which contain beryllium include beryl ( aquamarine , emerald ) and chrysoberyl . The free element is a steel-gray, strong, lightweight brittle alkaline earth metal . It is primarily

Iridium was discovered in 1803 by Smithson Tennant in London, England, among insoluble impurities in natural platinum from South America . Although it is one of the rarest elements in the Earth's crust , with annual production and consumption of only three tonnes , it has a number of specialized

or tungsten . On the other hand, it is known to form intermetallic compounds with antimony , gallium , indium and thorium , which are known to be photosensitive . [ 2 ] The alloy of 41 at.% caesium, 47 at.% potassium, and 12 at.% sodium has the lowest melting point of any known metal alloy

Remarkably, pure boron is a rare substance, boron tends to form refractory material containing small amounts of carbon or other elements. Several allotropes of boron exist: amorphous boron is a brown powder and crystalline boron is black, extremely hard (about 9.5 on Mohs' scale ), and a