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Greenleaf Whittier Pickard
Greenleaf Whittier Pickard (February 14, 1877, Portland, Maine – January 8, 1956, Newton, Massachusetts) was a United States radio pioneer. Pickard was a researcher in the early days of wireless. While not the earliest discoverer of the rectifying properties of contact between certain solid materials, he was largely responsible and most famous for the development of the crystal detector, the earliest type of diode detector. The crystal detector was the central component in many early radio receivers from around 1906 until about 1920. Pickard also experimented with antennas, radio wave propagation and noise suppression. On August 30, 1906 he filed a patent for a silicon crystal detector, which was granted on November 20, 1906. On June 10, 1907 he filed a patent for a Magnetic Aerial (a loop aerial) which was granted on January 21, 1908. Pickard's loop antenna had directional properties that could be used to reduce interference to the intended wireless communications. On June 21, 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenleaf Whittier Pickard In His Boston Laboratory
Greenleaf may refer to: Places United States Inhabited places * Greenleaf, California, former name of Gregg, California * Greenleaf, Idaho * Greenleaf, Kansas * Greenleaf, Minnesota * Greenleaf, Oregon * Greenleaf, Wisconsin * Greenleaf Township (other) Other places in the US * Greenleaf at Cheltenham, an outdoor shopping center in Philadelphia, Pennsylvania * Greenleaf Hut, an Appalachian Mountain Club hut in the White Mountains of New Hampshire * Greenleaf Peak, a mountain in the Cascade Range, Washington * Greenleaf Point, former name of Buzzard Point, Washington, D.C. * Greenleaf Lake (other) * Greenleaf Lake State Recreation Area, Minnesota * Greenleaf State Park, Oklahoma Publishers *Greenleaf Book Group, a publisher and book distributor (founded 1997), Austin, Texas, US *Greenleaf Publishing, a publisher of academic and professional books and journals (founded 1992), Yorkshire, UK * Greenleaf Publishing (1950s–1970s), a publishing house fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystal
A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macroscopic single crystals are usually identifiable by their geometrical shape, consisting of flat faces with specific, characteristic orientations. The scientific study of crystals and crystal formation is known as crystallography. The process of crystal formation via mechanisms of crystal growth is called crystallization or solidification. The word ''crystal'' derives from the Ancient Greek word (), meaning both "ice" and "rock crystal", from (), "icy cold, frost". Examples of large crystals include snowflakes, diamonds, and table salt. Most inorganic solids are not crystals but polycrystals, i.e. many microscopic crystals fused together into a single solid. Polycrystals include most metals, rocks, ceramics, and ice. A third category of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
People From Portland, Maine
A person ( : people) is a being that has certain capacities or attributes such as reason, morality, consciousness or self-consciousness, and being a part of a culturally established form of social relations such as kinship, ownership of property, or legal responsibility. The defining features of personhood and, consequently, what makes a person count as a person, differ widely among cultures and contexts. In addition to the question of personhood, of what makes a being count as a person to begin with, there are further questions about personal identity and self: both about what makes any particular person that particular person instead of another, and about what makes a person at one time the same person as they were or will be at another time despite any intervening changes. The plural form "people" is often used to refer to an entire nation or ethnic group (as in "a people"), and this was the original meaning of the word; it subsequently acquired its use as a plural form of per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IEEE Medal Of Honor Recipients
The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operations center in Piscataway, New Jersey. The mission of the IEEE is ''advancing technology for the benefit of humanity''. The IEEE was formed from the amalgamation of the American Institute of Electrical Engineers and the Institute of Radio Engineers in 1963. Due to its expansion of scope into so many related fields, it is simply referred to by the letters I-E-E-E (pronounced I-triple-E), except on legal business documents. , it is the world's largest association of technical professionals with more than 423,000 members in over 160 countries around the world. Its objectives are the educational and technical advancement of electrical and electronic engineering, telecommunications, computer engineering and similar disciplines. History Origins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Pioneers
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna which radiates the waves, and received by another antenna connected to a radio receiver. Radio is very widely used in modern technology, in radio communication, radar, radio navigation, remote control, remote sensing, and other applications. In radio communication, used in radio and television broadcasting, cell phones, two-way radios, wireless networking, and satellite communication, among numerous other uses, radio waves are used to carry information across space from a transmitter to a receiver, by modulating the radio signal (impressing an information signal on the radio wave by varying some aspect of the wave) in the transmitter. In radar, used to locate and track objects like aircraft, ships, spacecraft an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zincite
Zincite is the mineral form of zinc oxide ( Zn O). Its crystal form is rare in nature; a notable exception to this is at the Franklin and Sterling Hill Mines in New Jersey, an area also famed for its many fluorescent minerals. It has a hexagonal crystal structure and a color that depends on the presence of impurities. The zincite found at the Franklin Furnace is red-colored, mostly due to iron and manganese dopants, and associated with willemite and franklinite. Zincite crystals can be grown artificially, and synthetic zincite crystals are available as a by-product of zinc smelting. Synthetic crystals can be colorless or can range in color from dark red, orange, or yellow to light green. Both natural and synthetic zincite crystals are significant for their early use as semiconductor crystal detectors in the early development of crystal radios before the advent of vacuum tubes. As an early radio detector it was used in conjunction with another mineral, galena, and this devic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicon Carbide
Silicon carbide (SiC), also known as carborundum (), is a hard chemical compound containing silicon and carbon. A semiconductor, it occurs in nature as the extremely rare mineral moissanite, but has been mass-produced as a powder and crystal since 1893 for use as an abrasive. Grains of silicon carbide can be bonded together by sintering to form very hard ceramics that are widely used in applications requiring high endurance, such as car brakes, car clutches and ceramic plates in bulletproof vests. Large single crystals of silicon carbide can be grown by the Lely method and they can be cut into gems known as synthetic moissanite. Electronic applications of silicon carbide such as light-emitting diodes (LEDs) and Cat's whisker detector, detectors in early radios were first demonstrated around 1907. SiC is used in semiconductor electronics devices that operate at high temperatures or high voltages, or both. Natural occurrence Naturally occurring moissanite is found in only minut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molybdenite
Molybdenite is a mineral of molybdenum disulfide, Mo S2. Similar in appearance and feel to graphite, molybdenite has a lubricating effect that is a consequence of its layered structure. The atomic structure consists of a sheet of molybdenum atoms sandwiched between sheets of sulfur atoms. The Mo-S bonds are strong, but the interaction between the sulfur atoms at the top and bottom of separate sandwich-like tri-layers is weak, resulting in easy slippage as well as cleavage planes. Molybdenite crystallizes in the hexagonal crystal system as the common polytype 2H and also in the trigonal system as the 3R polytype. Description Occurrence Molybdenite occurs in high temperature hydrothermal ore deposits. Its associated minerals include pyrite, chalcopyrite, quartz, anhydrite, fluorite, and scheelite. Important deposits include the disseminated porphyry molybdenum deposits at Questa, New Mexico and the Henderson and Climax mines in Colorado. Molybdenite also occurs in porphyry cop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper Sulfate
Copper sulfate may refer to: * Copper(II) sulfate, CuSO4, a common compound used as a fungicide and herbicide * Copper(I) sulfate Copper(I) sulfate, also known as cuprous sulfate, is an inorganic compound with the chemical formula Cu2 SO4. It is a white solid that has attracted little attention, in contrast to copper(II) sulfate. It is an unusual example of a copper(I) ..., Cu2SO4, which is uncommonly used * Copper(II) sulfate, CuSO4 is greenish blue Copper compounds {{Chem-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Institute Of Radio Engineers
The Institute of Radio Engineers (IRE) was a professional organization which existed from 1912 until December 31, 1962. On January 1, 1963, it merged with the American Institute of Electrical Engineers (AIEE) to form the Institute of Electrical and Electronics Engineers (IEEE). Founding Following several attempts to form a technical organization of wireless practitioners in 1908–1912, the Institute of Radio Engineers (IRE) was finally established in 1912 in New York City. Among its founding organizations were the Society of Wireless Telegraph Engineers (SWTE) and the Wireless Institute (TWI). At the time, the dominant organization of electrical engineers was the American Institute of Electrical Engineers (AIEE). Many of the founding members of IRE considered AIEE too conservative and too focused on electric power. Moreover, the founders of the IRE sought to establish an international organization (unlike the “American” AIEE), and adopted a tradition of electing some of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Greenleaf Whittier
John Greenleaf Whittier (December 17, 1807 – September 7, 1892) was an American Quaker poet and advocate of the abolition of slavery in the United States. Frequently listed as one of the fireside poets, he was influenced by the Scottish poet Robert Burns. Whittier is remembered particularly for his anti-slavery writings, as well as his 1866 book ''Snow-Bound''. Biography Early life and work John Greenleaf Whittier was born to John and Abigail ( Hussey) Whittier at their rural homestead in Haverhill, Massachusetts, on December 17, 1807. His middle name is thought to mean ''feuillevert'', after his Huguenot forebears. He grew up on the farm in a household with his parents, a brother and two sisters, a maternal aunt and paternal uncle, and a constant flow of visitors and hired hands for the farm. As a boy, it was discovered that Whittier was color-blind when he was unable to see a difference between ripe and unripe strawberries. The farm was not very profitable, and there was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicon
Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, lead, and flerovium are below it. It is relatively unreactive. Because of its high chemical affinity for oxygen, it was not until 1823 that Jöns Jakob Berzelius was first able to prepare it and characterize it in pure form. Its oxides form a family of anions known as silicates. Its melting and boiling points of 1414 °C and 3265 °C, respectively, are the second highest among all the metalloids and nonmetals, being surpassed only by boron. Silicon is the eighth most common element in the universe by mass, but very rarely occurs as the pure element in the Earth's crust. It is widely distributed in space in cosmic dusts, planetoids, and planets as various forms of silicon dioxide ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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