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N Rays
N-rays (or N rays) were a hypothesized form of radiation, described by French physicist Prosper-René Blondlot in 1903, and initially confirmed by others, but subsequently found to be illusory. History Context The N-ray affair occurred shortly after a series of major breakthroughs in experimental physics. Victor Schumann discovered vacuum ultraviolet radiation in 1893, Wilhelm Röntgen discovered X-rays in 1895, Henri Becquerel discovered radioactivity in 1896, and, in 1897, J. J. Thomson discovered electrons, showing that they were the constituents of cathode rays. This created an expectation within the scientific community that other forms of radiation might be discovered. At this time, Prosper-René Blondlot was a professor of physics at the University of Nancy studying electromagnetic radiation. Blondlot was a respected member of the scientific community: he was one of eight physicists who were corresponding members of the French Academy of Sciences and was awa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speed Of Light
The speed of light in vacuum, commonly denoted , is a universal physical constant that is important in many areas of physics. The speed of light is exactly equal to ). According to the special theory of relativity, is the upper limit for the speed at which conventional matter or energy (and thus any signal carrying information) can travel through space. All forms of electromagnetic radiation, including visible light, travel at the speed of light. For many practical purposes, light and other electromagnetic waves will appear to propagate instantaneously, but for long distances and very sensitive measurements, their finite speed has noticeable effects. Starlight viewed on Earth left the stars many years ago, allowing humans to study the history of the universe by viewing distant objects. When communicating with distant space probes, it can take minutes to hours for signals to travel from Earth to the spacecraft and vice versa. In computing, the speed of light fixes the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gustave Le Bon
Charles-Marie Gustave Le Bon (; 7 May 1841 – 13 December 1931) was a leading French polymath whose areas of interest included anthropology, psychology, sociology, medicine, invention, and physics. He is best known for his 1895 work '' The Crowd: A Study of the Popular Mind'', which is considered one of the seminal works of crowd psychology. A native of Nogent-le-Rotrou, Le Bon qualified as a doctor of medicine at the University of Paris in 1866. He opted against the formal practice of medicine as a physician, instead beginning his writing career the same year of his graduation. He published a number of medical articles and books before joining the French Army after the outbreak of the Franco-Prussian War. Defeat in the war coupled with being a first-hand witness to the Paris Commune of 1871 strongly shaped Le Bon's worldview. He then travelled widely, touring Europe, Asia and North Africa. He analysed the peoples and the civilisations he encountered under the umbrella of the na ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archives D'électricité Médicale
An archive is an accumulation of historical records or materials – in any medium – or the physical facility in which they are located. Archives contain primary source documents that have accumulated over the course of an individual or organization's lifetime, and are kept to show the function of that person or organization. Professional archivists and historians generally understand archives to be records that have been naturally and necessarily generated as a product of regular legal, commercial, administrative, or social activities. They have been metaphorically defined as "the secretions of an organism", and are distinguished from documents that have been consciously written or created to communicate a particular message to posterity. In general, archives consist of records that have been selected for permanent or long-term preservation on grounds of their enduring cultural, historical, or evidentiary value. Archival records are normally unpublished and almost alway ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Green Wood
Green wood is wood that has been recently cut and therefore has not had an opportunity to season (dry) by evaporation of the internal moisture. Green wood contains more moisture than seasoned wood, which has been dried through passage of time or by forced drying in kilns. Green wood is considered to have 100% moisture content relative to air-dried or seasoned wood, which is considered to be 20%. Energy density charts for wood fuels tend to use air dried wood as their reference, thus oven dried or 0% moisture content can reflect 103.4% energy content. Combustion When green wood is used as fuel in appliances it releases less heat per unit of measure (usually cords or tons) because of the heat consumed to evaporate the moisture. Used for grilling and smoking meat, it can impart the meat with an unpleasant flavor. The lower temperatures that result can lead to more creosote being created which is later deposited in exhaust flues. These deposits can later be ignited when sufficie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arsène D'Arsonval
Arsène is a masculine French given name. It is derived from the Latin name ''Arsenius'', the Latinized form of the Greek name Ἀρσἐνιος (''Arsenios''), which means "male, virile". It has also been used as a surname. It may refer to: Given name * Arsène Alancourt (1904–1965), French professional road bicycle racer * Arsène Alexandre (1859–1937), French art critic * Arsène Auguste (1951–1993), Haitian footballer * Arsène Copa (born 1988), Gabonese footballer * Arsène Darmesteter (1846–1888), French philologist * Arsène de Cey (1806–1887), French playwright and novelist * Arsène Do Marcolino (born 1986), Gabonese footballer * Arsène Heitz (1908–1989), French draughtsman, co-creator of the Flag of Europe * Arsène Herbinier (1869-1955), French lithograph artist * Arsène Houssaye (1815-1896), French novelist and poet * Arsene James (born 1944), Saint Lucian politician * Arsène Kra Konan (born 19??), Ivorian sprinter * Arsène Menessou (born 1987) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Augustin Charpentier
Augustin Charpentier (1852 – 4 August 1916) was a French physician. In 1891 he carried out the first experiment providing evidence of the size-weight illusion. He carried out a various number of procedures comparing what people thought was the heaviness of lifted weights. He realized that lifters thought that larger objects were lighter than smaller objects of the same mass. See also * Size–weight illusion External links * http://www.professeurs-medecine-nancy.fr/Charpentier_A.htm (in French) 19th-century French physicians 1852 births 1916 deaths {{France-med-bio-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
London
London is the capital and List of urban areas in the United Kingdom, largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a major settlement for two millennia. The City of London, its ancient core and financial centre, was founded by the Roman Empire, Romans as ''Londinium'' and retains its medieval boundaries.See also: Independent city#National capitals, Independent city § National capitals The City of Westminster, to the west of the City of London, has for centuries hosted the national Government of the United Kingdom, government and Parliament of the United Kingdom, parliament. Since the 19th century, the name "London" has also referred to the metropolis around this core, historically split between the Counties of England, counties of Middlesex, Essex, Surrey, Kent, and Hertfordshire, which largely comprises Greater London ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longmans, Green & Co
Longman, also known as Pearson Longman, is a publishing company founded in London, England, in 1724 and is owned by Pearson PLC. Since 1968, Longman has been used primarily as an imprint by Pearson's Schools business. The Longman brand is also used for the Longman Schools in China and the ''Longman Dictionary''. History Beginnings The Longman company was founded by Thomas Longman (1699 – 18 June 1755), the son of Ezekiel Longman (died 1708), a gentleman of Bristol. Thomas was apprenticed in 1716 to John Osborn, a London bookseller, and at the expiration of his apprenticeship married Osborn's daughter. In August 1724, he purchased the stock and household goods of William Taylor, the first publisher of ''Robinson Crusoe'', for 9s 6d. Taylor's two shops in Paternoster Row, London, were known respectively as the ''Black Swan'' and the ''Ship'', premises at that time having signs rather than numbers, and became the publishing house premises. Longman entered into partn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spark Gap
A spark gap consists of an arrangement of two conducting electrodes separated by a gap usually filled with a gas such as air, designed to allow an electric spark to pass between the conductors. When the potential difference between the conductors exceeds the breakdown voltage of the gas within the gap, a spark forms, ionizing the gas and drastically reducing its electrical resistance. An electric current then flows until the path of ionized gas is broken or the current reduces below a minimum value called the "holding current". This usually happens when the voltage drops, but in some cases occurs when the heated gas rises, stretching out and then breaking the filament of ionized gas. Usually, the action of ionizing the gas is violent and disruptive, often leading to sound (ranging from a ''snap'' for a spark plug to thunder for a lightning discharge), light and heat. Spark gaps were used historically in early electrical equipment, such as spark gap radio transmitters, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Spark
An electric spark is an abrupt electrical discharge that occurs when a sufficiently high electric field creates an ionized, electrically conductive channel through a normally-insulating medium, often air or other gases or gas mixtures. Michael Faraday described this phenomenon as "the beautiful flash of light attending the discharge of common electricity". The rapid transition from a non-conducting to a conductive state produces a brief emission of light and a sharp crack or snapping sound. A spark is created when the applied electric field exceeds the dielectric breakdown strength of the intervening medium. For air, the breakdown strength is about 30 kV/cm at sea level. Experimentally, this figure tends to differ depending upon humidity, atmospheric pressure, shape of electrodes (needle and ground-plane, hemispherical etc.) and the corresponding spacing between them and even the type of waveform, whether sinusoidal or cosine-rectangular. At the beginning stages, free electrons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polarization (waves)
Polarization ( also polarisation) is a property applying to transverse waves that specifies the geometrical orientation of the oscillations. In a transverse wave, the direction of the oscillation is perpendicular to the direction of motion of the wave. A simple example of a polarized transverse wave is vibrations traveling along a taut string ''(see image)''; for example, in a musical instrument like a guitar string. Depending on how the string is plucked, the vibrations can be in a vertical direction, horizontal direction, or at any angle perpendicular to the string. In contrast, in longitudinal waves, such as sound waves in a liquid or gas, the displacement of the particles in the oscillation is always in the direction of propagation, so these waves do not exhibit polarization. Transverse waves that exhibit polarization include electromagnetic waves such as light and radio waves, gravitational waves, and transverse sound waves ( shear waves) in solids. An electromag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
