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The crystal detector was developed into a practical device for wireless telegraphy by Greenleaf Whittier Pickard, who invented a silicon crystal detector in 1903 and received a patent for it on November 20, 1906.
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crystal and detector
The crystal detector in these early crystal radio sets consisted of an adjustable wire point-contact ( the so-called " cat's whisker "), which could be manually moved over the face of the crystal in order to obtain optimum signal.
This troublesome device was superseded by thermionic diodes by the 1920s, but after high purity semiconductor materials became available, the crystal detector returned to dominant use with the advent of inexpensive fixed-germanium diodes in the 1950s.
Round of Marconi Labs, using a crystal of silicon carbide and a cat's-whisker detector.
The point-contact crystal detector became vital for microwave radio systems, since available vacuum tube devices could not serve as detectors above about 4000 MHz ; advanced radar systems relied on the fast response of crystal detectors.
When they land on a piece of film or other detector, these beams make a diffraction pattern of spots ; the strengths and angles of these beams are recorded as the crystal is gradually rotated.
The detector ( red box ) can be slid closer or further away from the crystal, allowing higher resolution data to be taken ( if closer ) or better discernment of the Bragg peaks ( if further away ).
Early radio receivers, called crystal radios, used a " cat's whisker " of fine wire pressing on a crystal of galena ( lead sulfide ) to serve as a point-contact rectifier or " crystal detector ".
* Acoustic detector ( crystal transducer and solid-state amplifier ) to detect micrometeorite ( cosmic dust ) impacts.
*" Simultaneous " spectrometers have a number of " channels " dedicated to analysis of a single element, each consisting of a fixed-geometry crystal monochromator, a detector, and processing electronics.
The instrument is programmed to move through a sequence of wavelengths, in each case selecting the appropriate X-ray tube power, the appropriate crystal, and the appropriate detector arrangement.
The common feature of monochromators is the maintenance of a symmetrical geometry between the sample, the crystal and the detector.
The earliest crystal radio receivers used a crystal diode detector with no amplification.
The PDS was a crystal ( sodium iodide / caesium iodide ) scintillator detector capable of absorbing photons up to 300 keV ( 48, 000 aJ ).
It gets its name from its most important component, known as a crystal detector, originally made with a piece of crystalline mineral such as galena.
Crystal radios are the simplest type of radio receiver and can be handmade with a few inexpensive parts, like an antenna wire, tuning coil of copper wire, crystal detector and earphones.
crystal and was
The measured powder density of the Af used here was about Af, approximately one-third that of the crystal density ( Af ).
The present edition of crystal data was written by J.D.H. Donnay, the Johns Hopkins University, Baltimore, Md. ( Part 2 ) ) and Werner Nowacki, University of Berne, Switzerland ( Part 1 ) ) with the collaboration of Gabrielle Donnay, U. S. Geological Survey, Washington, D. C..
But he was looking forward to snow -- seeing for himself that each tiny crystal of the water of life was a unique individual, as he had read -- walking barefoot, rolling in it.
In the early 20th century it was recognized that other cases such as carbon were due to differences in crystal structure.
Edgar Cayce first mentioned Atlantis in 1923 and later suggested that it was originally a continent-sized region extending from the Azores to the Bahamas, holding an ancient, highly evolved civilization which had ships and aircraft powered by a mysterious form of energy crystal.
Gropius was not necessarily against Expressionism, and in fact himself in the same 1919 pamphlet proclaiming this " new guild of craftsmen, without the class snobbery ," described " painting and sculpture rising to heaven out of the hands of a million craftsmen, the crystal symbol of the new faith of the future.
The mathematics of crystal structures developed by Bravais, Federov and others was used to classify crystals by their symmetry group, and tables of crystal structures were the basis for the series International Tables of Crystallography, first published in 1935.
The wave-like behaviour of Cathode Ray particles was later directly demonstrated using a crystal lattice by Davisson and Germer in 1927.
This was an enormous spacefaring crystal lattice that had taken thousands of lives in its quest for energy.
In the early 1970s liquid crystal displays ( LCDs ) were in their infancy and there was a great deal of concern that they only had a short operating lifetime.
Although the crystal semiconductor diode was popular before the thermionic diode, thermionic ( vacuum tube ) diodes and solid state ( semiconductor ) diodes were developed in parallel.
Indian scientist Jagadish Chandra Bose was the first to use a crystal for detecting radio waves in 1894.
Also, gallium metal easily alloys with many metals, and was used in small quantities as a plutonium-gallium alloy in the plutonium cores of the first and third nuclear bombs, to help stabilize the plutonium crystal structure.
In 2000, the first crystal structure of a mammalian GPCR, that of bovine rhodopsin (), was solved.
It was classically argued that the binding of an oxygen molecule placed high-spin iron ( II ) in an octahedral field of strong-field ligands ; this change in field would increase the crystal field splitting energy, causing iron's electrons to pair into the low-spin configuration, which would be diamagnetic in Fe ( II ).
An example is the long-awaited crystal structure of a voltage-gated potassium channel, which was reported in May 2003.
* In 1972, the first active-matrix liquid crystal display panel was produced in the United States by Westinghouse, in Pittsburgh, Pennsylvania.
The next step to commercialization of liquid crystal displays was the synthesis of further chemically stable substances ( cyanobiphenyls ) with low melting temperatures by George Gray.
It has a particularly complicated crystal structure that was only fully described in 1986.
* X-Men Adventures-Originally based on the X-Men animated series, this universe went on to feature more original stories, and in its final issue, revealed itself to be the universe which existed prior to the current 616 reality, when it was destroyed by the fracturing of the M ' Kraan crystal.
crystal and developed
Researchers at the US Department of Energy's Lawrence Berkeley National Laboratory ( Berkeley Lab ) have developed a piezoelectric generator sufficient to operate a liquid crystal display using thin films of M13 bacteriophage.
Kent Displays has also developed a " no power " display that uses polymer stabilized cholesteric liquid crystal ( ChLCD ).
In 1991, when liquid crystal displays were already well established, Pierre-Gilles de Gennes received the Nobel Prize in physics " for discovering that methods developed for studying order phenomena in simple systems can be generalized to more complex forms of matter, in particular to liquid crystals and polymers ".
The human alpha-satellite palindromic DNA critical to achieving the 1997 nucleosome crystal structure was developed by the Bunick group at Oak Ridge National Laboratory in Tennessee.
Following World War I, Frederick R. Lack, working in radio telephony in the engineering department, developed the “ AT cut ” crystal, a crystal that operated through a wide range of temperatures.
This lab developed many innovations, such as color television, the electron microscope, CMOS-based technology, heterojunction physics, optoelectronic emitting devices, liquid crystal displays ( LCDs ), videocassette recorders, direct broadcast television, direct broadcast satellite systems and high-definition television.
Von Laue developed a law that connects the scattering angles and the size and orientation of the unit-cell spacings in the crystal, for which he was awarded the Nobel Prize in Physics in 1914.
In 1912 – 1913, the younger Bragg developed Bragg's law, which connects the observed scattering with reflections from evenly spaced planes within the crystal.
Quartz crystal oscillators were developed for high-stability frequency references during the 1920s and 1930s.
In 1928, Warren Marrison ( of Bell Telephone Laboratories ) developed the first quartz crystal clock.
* 1968 – Liquid crystal display developed by RCA
Displays using this technology were manufactured for medical and vehicle applications where ruggedness and wide viewing angles were crucial, and liquid crystal displays were not well developed.
The rectifying property of crystals was discovered in 1874 by Karl Ferdinand Braun, and crystal detectors were developed and applied to radio receivers in 1904 by Jagadish Chandra Bose, G. W. Pickard and others.
A current is passed through the crystal which, when placed in a magnetic field has a “ Hall effect ” voltage developed across it.
While performing with Wild Orchid, Ferguson developed an addiction to crystal methamphetamine which followed her after she left the group in 2001.
* HRL claims to have developed the liquid crystal watch in 1975.
Photonic crystal fibres were first developed by Philip Russell in 1998, and can be designed to possess enhanced properties over ( normal ) optical fibres.
Using fiber draw techniques developed for communications fiber it meets these two requirements, and photonic crystal fibres are commercially available.
Some of the most important technologies developed from work at RSRE are radar, thermal imaging, liquid crystal displays and speech synthesis.
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