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1917 In Science
The year 1917 in science and technology involved some significant events, listed below. Biology * September 3 – French-Canadian microbiologist Félix d'Hérelle, working at the Pasteur Institute in Paris, announces his discovery of a bacteriophage. * D'Arcy Wentworth Thompson's ''On Growth and Form'' is published. Mathematics * Paul Ehrenfest gives a conditional principle for a three-dimensional space. Medicine * Shinobu Ishihara publishes his color perception test. * Julius Wagner-Jauregg discovers malarial pyrotherapy for general paresis of the insane. Physics * Albert Einstein Albert Einstein (14 March 187918 April 1955) was a German-born theoretical physicist who is best known for developing the theory of relativity. Einstein also made important contributions to quantum mechanics. His mass–energy equivalence f ... introduces the idea of Laser, stimulated radiation emission. * Nuclear fission: Ernest Rutherford (at the Victoria University of Manchester) a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Fission
Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radioactive decay. Nuclear fission was discovered by chemists Otto Hahn and Fritz Strassmann and physicists Lise Meitner and Otto Robert Frisch. Hahn and Strassmann proved that a fission reaction had taken place on 19 December 1938, and Meitner and her nephew Frisch explained it theoretically in January 1939. Frisch named the process "fission" by analogy with biological fission of living cells. In their second publication on nuclear fission in February 1939, Hahn and Strassmann predicted the existence and liberation of additional neutrons during the fission process, opening up the possibility of a nuclear chain reaction. For heavy nuclides, it is an exothermic reaction which can release large amounts of energy both as electromagnetic radiat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nobel Prize
The Nobel Prizes ( ; ; ) are awards administered by the Nobel Foundation and granted in accordance with the principle of "for the greatest benefit to humankind". The prizes were first awarded in 1901, marking the fifth anniversary of Alfred Nobel, Alfred Nobel's death. The original Nobel Prizes covered five fields: Nobel Prize in Physics, physics, Nobel Prize in Chemistry, chemistry, Nobel Prize in Physiology or Medicine, physiology or medicine, Nobel Prize in Literature, literature, and Nobel Peace Prize, peace, specified in Nobel's will. A sixth prize, the Nobel Memorial Prize in Economic Sciences, Prize in Economic Sciences, was established in 1968 by Sveriges Riksbank (Sweden's central bank) in memory of Alfred Nobel. The Nobel Prizes are widely regarded as the most prestigious awards available in their respective fields.Nobel Prize#Shalev69, Shalev, p. 8. Except in extraordinary circumstances, such as war, all six prizes are given annually. Each recipient, known as a laur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Encryption
In Cryptography law, cryptography, encryption (more specifically, Code, encoding) is the process of transforming information in a way that, ideally, only authorized parties can decode. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Despite its goal, encryption does not itself prevent interference but denies the intelligible content to a would-be interceptor. For technical reasons, an encryption scheme usually uses a pseudo-random encryption Key (cryptography), key generated by an algorithm. It is possible to decrypt the message without possessing the key but, for a well-designed encryption scheme, considerable computational resources and skills are required. An authorized recipient can easily decrypt the message with the key provided by the originator to recipients but not to unauthorized users. Historically, various forms of encryption have been used to aid in cryptography. Early encryption ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
One-time Pad
The one-time pad (OTP) is an encryption technique that cannot be Cryptanalysis, cracked in cryptography. It requires the use of a single-use pre-shared key that is larger than or equal to the size of the message being sent. In this technique, a plaintext is paired with a random secret Key (cryptography), key (also referred to as a ''one-time pad''). Then, each bit or character of the plaintext is encrypted by combining it with the corresponding bit or character from the pad using Modular arithmetic, modular addition. The resulting ciphertext is impossible to decrypt or break if the following four conditions are met: # The key must be at least as long as the plaintext. # The key must be True random, truly random. # The key must never be reused in whole or in part. # The key must be kept completely secret by the communicating parties. These requirements make the OTP the only known encryption system that is mathematically proven to be unbreakable under the principles of informat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gilbert Vernam
Gilbert Sandford Vernam (April 3, 1890 – February 7, 1960) was a Worcester Polytechnic Institute 1914 graduate and AT&T Bell Labs engineer who, in 1917, invented an additive polyalphabetic stream cipher and later co-invented an automated one-time pad cipher. Vernam proposed a teleprinter cipher in which a previously prepared key, kept on paper tape, is combined character by character with the plaintext message to produce the ciphertext. To decipher the ciphertext, the same key would be again combined character by character, producing the plaintext. Vernam later worked for the Postal Telegraph Company, and became an employee of Western Union when that company acquired Postal in 1943. His later work was largely with automatic switching systems for telegraph networks. Vernam's patent The combining function Vernam specified in , issued July 22, 1919, is the XOR operation, applied to the individual impulses or bits used to encode the characters in the Baudot code. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Banjolele
The banjo ukulele, also known as the banjolele or banjo uke, is a four-stringed musical instrument with a small banjo-type body and a fretted ukulele neck. The earliest known banjoleles were built by John A. Bolander and by Alvin D. Keech, both in 1917. The instrument achieved its greatest popularity in the 1920s and 1930s, and combines the small scale, tuning, and playing style of a ukulele with the construction and distinctive tone of a banjo, hence the name. Its development was pushed by the need for vaudeville performers to have an instrument that could be played with the ease of the ukulele, but with more volume. Construction and tuning In terms of overall construction, banjo ukuleles parallel banjos, though on a smaller scale. They are always fretted. Most are built of wood with metal accoutrements, although the mid-century "Dixie" brand featured banjo ukuleles made from solid metal. The banjo ukulele neck typically has sixteen frets, and is the same scale length as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kelvin Keech
Kelvin Kirkwood Keech (June 28, 1895 – May 22, 1977) was an American actor, producer and old-time radio announcer. Keech was known for being the announcer for several popular old-time radio programs including '' The Eveready Hour'', ''Bill and Betty'', '' Popeye the Sailor'' and '' Terry and the Pirates''. Keech was also known for remaking and redistributing the banjolele with his brother Alvin Keech in 1917. Early life Kelvin Kirkwood Keech was born on June 28, 1895, in Honolulu, Republic of Hawaii to parents Alvin Welty Keech and Isabella Keech (née Weir). He had an elder brother Alvin Danglada Keech (1890 - May 22, 1948) who was also an expert banjo player. Kelvin Keech went to and graduated from Franklin & Marshall College in Lancaster, Pennsylvania, before concluding his studies in Boston. Career The Keech Studios In 1915, the Keech brothers founded The Keech Studios which was located at 435 Powell Street in San Francisco, California. The studio was responsible for th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Gulf Between (1917 Film)
''The Gulf Between'' is a 1917 American comedy-drama film that was the first motion picture made in Technicolor, the fourth feature-length color film, and the first feature-length color film produced in the United States. A copy of the film was destroyed in a fire on March 25, 1961 and the film is considered a lost film, with only very short fragments known to survive. These fragments are in the collections of the Margaret Herrick Library, George Eastman House Motion Picture Collection, and the Smithsonian National Museum of American History Photographic History Collection. ''The Gulf Between'', which had a running time of approximately 58 minutes, was directed by Wray Physioc. The lead roles were played by Grace Darmond and Niles Welch. Plot As described in the film magazine '' Exhibitors Herald'', little Marie Farrell (Axzelle), through the carelessness of her nurse, is lost and believed drowned. She has wandered upon the ship of the smuggler Captain Flagg (Brandt), who fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Technicolor
Technicolor is a family of Color motion picture film, color motion picture processes. The first version, Process 1, was introduced in 1916, and improved versions followed over several decades. Definitive Technicolor movies using three black-and-white films running through a special camera (3-strip Technicolor or Process 4) started in the early 1930s and continued through to the mid-1950s, when the 3-strip camera was replaced by a standard camera loaded with single-strip "monopack" color negative film. Technicolor Laboratories were still able to produce Technicolor prints by creating three black-and-white matrices from the Eastmancolor negative (Process 5). Process 4 was the second major color process, after Britain's Kinemacolor (used between 1909 and 1915), and the most widely used color process in Cinema of the United States, Hollywood during the Golden Age of Hollywood. Technicolor's #Process 4: Development and introduction, three-color process became known and cele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proton
A proton is a stable subatomic particle, symbol , Hydron (chemistry), H+, or 1H+ with a positive electric charge of +1 ''e'' (elementary charge). Its mass is slightly less than the mass of a neutron and approximately times the mass of an electron (the proton-to-electron mass ratio). Protons and neutrons, each with a mass of approximately one Dalton (unit), dalton, are jointly referred to as ''nucleons'' (particles present in atomic nuclei). One or more protons are present in the Atomic nucleus, nucleus of every atom. They provide the attractive electrostatic central force which binds the atomic electrons. The number of protons in the nucleus is the defining property of an element, and is referred to as the atomic number (represented by the symbol ''Z''). Since each chemical element, element is identified by the number of protons in its nucleus, each element has its own atomic number, which determines the number of atomic electrons and consequently the chemical characteristi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Reaction
In nuclear physics and nuclear chemistry, a nuclear reaction is a process in which two atomic nucleus, nuclei, or a nucleus and an external subatomic particle, collide to produce one or more new nuclides. Thus, a nuclear reaction must cause a transformation of at least one nuclide to another. If a nucleus interacts with another nucleus or particle, they then separate without changing the nature of any nuclide, the process is simply referred to as a type of nuclear scattering, rather than a nuclear reaction. In principle, a reaction can involve more than two particles collision, colliding, but because the probability of three or more nuclei to meet at the same time at the same place is much less than for two nuclei, such an event is exceptionally rare (see triple alpha process for an example very close to a three-body nuclear reaction). The term "nuclear reaction" may refer either to a change in a nuclide induced by collision with another particle or to a spontaneous change of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
