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Transit of Venus, 2012
The 2012 transit of Venus, when the planet Venus appeared as a small, dark spot passing across the face of the Sun, began at 22:09 UTC on 5 June 2012, and finished at 04:49 UTC on 6 June. Depending on the position of the observer, the exact times varied by up to ±7 minutes. Transits of Venus are among the rarest of predictable celestial phenomena and occur in pairs. Consecutive transits per pair are spaced 8 years apart, and consecutive pairs occur more than a century apart: The previous transit of Venus took place on 8 June 2004 (preceded by transits on 9 December 1874 and 6 December 1882); the next pair of transits will occur on 10–11 December 2117 and in December 2125.
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Biography
Abraham Esau
Robert Abraham Esau (7 June 1884 – 12 May 1955) was a German physicist. After receipt of his doctorate from the University of Berlin, Esau worked at Telefunken, where he pioneered very high frequency (VHF) waves used in radar, radio, and television, and he was president of the Deutscher Telefunken Verband. During World War I, he was a prisoner of war of the French; he was repatriated to Germa
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Topic Review
List of Unnumbered Minor Planets: 2003 A–R
This is a partial list of unnumbered minor planets for principal designations assigned between 1 January 2003 and 15 September 2003 (A–R).
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Topic Review
Half-Reaction
A half reaction (or half-cell reaction) is either the oxidation or reduction reaction component of a redox reaction. A half reaction is obtained by considering the change in oxidation states of individual substances involved in the redox reaction. Often, the concept of half reactions is used to describe what occurs in an electrochemical cell, such as a Galvanic cell battery. Half reactions can be written to describe both the metal undergoing oxidation (known as the anode) and the metal undergoing reduction (known as the cathode). Half reactions are often used as a method of balancing redox reactions. For oxidation-reduction reactions in acidic conditions, after balancing the atoms and oxidation numbers, one will need to add H+ ions to balance the hydrogen ions in the half reaction. For oxidation-reduction reactions in basic conditions, after balancing the atoms and oxidation numbers, first treat it as an acidic solution and then add OH− ions to balance the H+ ions in the half reactions (which would give H2O).
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Topic Review
PSR B1620-26 B
PSR B1620-26 b is an extrasolar planet located approximately 12,400 light-years away from Earth in the constellation of Scorpius. It bears the unofficial nicknames "Methuselah" and "the Genesis planet" due to its extreme age and a few popular sources refer to this object as "PSR B1620-26 c" (see below for discussion). The planet is in a circumbinary orbit around the two stars of PSR B1620-26 (which are a pulsar (PSR B1620-26 A) and a white dwarf (WD B1620-26)) and is the first circumbinary planet ever confirmed. It is also the first planet found in a globular cluster. The planet is one of the oldest known extrasolar planets, believed to be about 12.7 billion years old.
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Topic Review
Soyuz TM-23
Soyuz TM-23 was a Soyuz spaceflight which launched on February 21, 1996, to Mir. The spacecraft launched from Baikonur Cosmodrome, and after two days of flight, Yuri Onufrienko and Yury Usachov docked with Mir and became the 21st resident crew of the Station. On September 2, 1996, after 191 days docked with Mir, the ship undocked with the launch crew and Claudie André-Deshays onboard, before eventually landing 107 km (66 mi) south west of Akmola, Kazakhstan.
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Biography
Shin-Tson Wu
Shin-Tson Wu, (Chinese:吳詩聰) is an American physicist and inventor. He is currently a Pegasus professor at CREOL, The College of Optics and Photonics, University of Central Florida. Wu's contributions to liquid-crystal research and the resulting patent portfolio for next-generation liquid crystal displays (LCDs), adaptive optics, laser-beam steering, biophotonics, and new photonic materials
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Biography
Sharon Glotzer
Sharon C. Glotzer is an United States "digital alchemist,"[1] the John Werner Cahn Distinguished University Professor of Engineering and the Stuart W. Churchill Collegiate Professor of Chemical Engineering at the University of Michigan, where she is also Professor of Materials Science & Engineering, Professor of Physics, Professor of Macromolecular Science & Engineering, and Professor of Applied
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Topic Review
Chemical Ionization
Chemical ionization (CI) is a soft ionization technique used in mass spectrometry. This was first introduced by Burnaby Munson and Frank H. Field in 1966. This technique is a branch of gaseous ion-molecule chemistry. Reagent gas molecules (often methane or ammonia) are ionized by electron ionization to form reagent ions, which subsequently react with analyte molecules in the gas phase to create analyte ions for analysis by mass spectrometry. Negative chemical ionization (NCI), charge-exchange chemical ionization, atmospheric-pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) are some of the common variants of the technique. CI mass spectrometry finds general application in the identification, structure elucidation and quantitation of organic compounds as well as some utility in biochemical analysis. Samples to be analyzed must be in vapour form, or else (in the case of liquids or solids), must be vapourized before introduction into the source.
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Topic Review
Plasma
Plasma (from grc πλάσμα (plásma) 'moldable substance') is one of the four fundamental states of matter. It contains a significant portion of charged particles – ions and/or electrons. The presence of these charged particles is what primarily sets plasma apart from the other fundamental states of matter. It is the most abundant form of ordinary matter in the universe, being mostly associated with stars, including the Sun. It extends to the rarefied intracluster medium and possibly to intergalactic regions. Plasma can be artificially generated by heating a neutral gas or subjecting it to a strong electromagnetic field. The presence of charged particles makes plasma electrically conductive, with the dynamics of individual particles and macroscopic plasma motion governed by collective electromagnetic fields and very sensitive to externally applied fields. The response of plasma to electromagnetic fields is used in many modern technological devices, such as plasma televisions or plasma etching. Depending on temperature and density, a certain amount of neutral particles may also be present, in which case plasma is called partially ionized. Neon signs and lightning are examples of partially ionized plasmas. Unlike the phase transitions between the other three states of matter, the transition to plasma is not well defined and is a matter of interpretation and context. Whether a given degree of ionization suffices to call a substance 'plasma' depends on the specific phenomenon being considered.
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