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Crystal optics - Wikipedia, the free encyclopedia
Crystal optics is the branch of optics that describes the behaviour of light in anisotropic media , that is, media (such as crystals ) in which light behaves differently depending on which direction the light is propagating. The index of refraction depends on both composition and crystal structure and can be calculated using the Gladstone–Dale relation . Crystals are often naturally anisotropic, and in some media (such as liquid crystals ) it is possible to induce anisotropy by applying an external electric field.
The Wacker Oxidation is an industrial process, which allows the synthesis of ethanal from ethene by palladium-catalyzed oxidation with oxygen. Copper serves as redox cocatalyst. The lab scale modification - the Wacker-Tsuji Oxidation - is useful for the synthesis of various ketones.
Wacker-Tsuji Oxidation
August Becker (17 August 1900, Staufenberg, Hesse - 31 December 1967) was during the Nazi regime in Germany (1933–1945) an SS lieutenant colonel ( Obersturmbannführer ) and chemist in the Central Reich Security Office ( RSHA ). He helped design the vans with a gas chamber built into the back compartment used in early Nazi mass murder of disabled people, political dissidents, Jews, and other "racial enemies," including Action T4 as well as the Einsatzgruppen (mobile Nazi death squads) in the Nazi-occupied portions of the Soviet Union . Generally his role was to provide important technical support, but on at least one occasion he personally gassed about 20 people.
August Becker - Wikipedia, the free encyclopedia
Sensing element of the SQUID A SQUID (for superconducting quantum interference device ) is a very sensitive magnetometer used to measure extremely subtle magnetic fields , based on superconducting loops containing Josephson junctions . SQUIDs are sensitive enough to measure fields as low as 5 a T (5×10 −18 T) within a few days of averaged measurements. [ 1 ] Their noise levels are as low as 3 f T· Hz -½ . [ 2 ] For comparison, a typical refrigerator magnet produces 0.01 tesla (10 −2 T), and some processes in animals produce very small magnetic fields between 10 −9 T and 10 −6 T. Recently invented SERF atomic magnetometers are potentially more sensitive and do not require cryogenic refrigeration but are orders of magnitude larger in size (~1 cm 3 ) and must be operated in a near-zero magnetic field.
SQUID - Wikipedia, the free encyclopedia
Execution van - Wikipedia, the free encyclopedia
Execution vans , also referred to as "mobile execution units", were developed by the government of the People's Republic of China and were first used in 1997. There is evidence that mobile execution chambers existed prior to 1997, the state of Delaware in the United States of America purchased a mobile lethal injection chamber as early as 1986. [ 1 ] Prisoners are strapped to a stretcher and executed via lethal injection inside the van. The vans allow for death sentences to be carried out without having to move the prisoner to an execution ground. The vans also require less manpower per execution, requiring only four people to assist with the injection. [ 2 ] Although the PRC claims that the vans are more humane than previous forms of execution, human rights groups predict the execution rate in China will increase because of mobile capital punishment. [ 3 ]
The Eötvös effect is the change in perceived gravitational force caused by the change in centrifugal acceleration resulting from eastbound or westbound velocity. When moving eastbound, the object's angular velocity is increased (in addition to the earth's rotation ), and thus the centrifugal force also increases, causing a perceived reduction in gravitational force. In the early 1900s a German team from the Institute of Geodesy in Potsdam carried out gravity measurements on moving ships in the Atlantic, Indian and Pacific Oceans.
Eötvös effect - Wikipedia, the free encyclopedia
Magnetoencephalography ( MEG ) is a technique for mapping brain activity by recording magnetic fields produced by electrical currents occurring naturally in the brain , using very sensitive magnetometers . Arrays of SQUIDs (superconducting quantum interference devices) are currently the most common magnetometer, and SERF being investigated for future machines. Applications of MEG include basic research into perceptual and cognitive brain processes, localizing regions affected by pathology before surgical removal, determining the function of various parts of the brain, and neurofeedback . [ edit ] History of MEG
Magnetoencephalography - Wikipedia, the free encyclopedia
Nucleotide - Wikipedia, the free encyclopedia
Nucleotides are molecules that, when joined together, make up the structural units of RNA and DNA . In addition, nucleotides participate in cellular signaling ( cGMP and cAMP ), and are incorporated into important cofactors of enzymatic reactions ( coenzyme A , FAD , FMN , and NADP + ). Nucleotide derivatives such as the nucleoside triphosphates play central roles in metabolism , in which capacity they serve as sources of chemical energy ( ATP and GTP ). [ 1 ]
The CANDU (short for CANada Deuterium Uranium ) reactor is a Canadian-invented, pressurized heavy water reactor . The acronym refers to its deuterium-oxide ( heavy water ) moderator and its use of (originally, natural ) uranium fuel. CANDU reactors were first developed in the late 1950s and 1960s by a partnership between Atomic Energy of Canada Limited (AECL), the Hydro-Electric Power Commission of Ontario (now Ontario Power Generation ), Canadian General Electric (now GE Canada), and other companies. All power reactors built in Canada are of the CANDU type. The reactor is also marketed abroad and there are CANDU-type units operating in India , Pakistan , Argentina , South Korea , Romania and China . In October 2011, the Canadian Federal Government licensed the CANDU design to Candu Energy (a wholly owned subsidiary of SNC-Lavalin ), which also acquired the former reactor development and marketing division of AECL at that time.
