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Perley Ason Ross
Perley Ason Ross (6 April 1883 – 13 March 1939) was a U.S. experimental physicist who worked, carefully and without seeking publicity, at some essential problems in the behaviour of X-rays. Born in Panacea, Missouri he was awarded his PhD from Stanford University in 1911, becoming a full professor there in 1927, after a year at Cornell University. Some of his principal studies included: *Scattering of X-rays by matter; *Development of the Ross differential filter for X-ray spectroscopy; *X-ray polarization; *Compton scattering; and *Radiative Auger effect In optics and spectroscopy, the radiative Auger effect is a decay channel of an inner-shell atomic vacancy state, in which an X-ray photon is emitted accompanying simultaneous promotion of an electron into either a bound or a continuum state. Thus t .... His daughter, Betsy, married fellow Stanford physicist William Webster Hansen.Süsskind, C. (1981) "Hansen, William Webster" in References 1883 births 1938 deaths S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Experiment
An experiment is a procedure carried out to support or refute a hypothesis, or determine the efficacy or likelihood of something previously untried. Experiments provide insight into cause-and-effect by demonstrating what outcome occurs when a particular factor is manipulated. Experiments vary greatly in goal and scale but always rely on repeatable procedure and logical analysis of the results. There also exist natural experimental studies. A child may carry out basic experiments to understand how things fall to the ground, while teams of scientists may take years of systematic investigation to advance their understanding of a phenomenon. Experiments and other types of hands-on activities are very important to student learning in the science classroom. Experiments can raise test scores and help a student become more engaged and interested in the material they are learning, especially when used over time. Experiments can vary from personal and informal natural comparisons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Polarization (waves)
, or , is a property of transverse waves which 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. One example of a polarized transverse wave is vibrations traveling along a taut string, 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 electromagnetic wave such as light consists of a coupled oscillating el ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Stanford University Alumni
Leland Stanford Junior University, commonly referred to as Stanford University, is a private research university in Stanford, California, United States. It was founded in 1885 by railroad magnate Leland Stanford (the eighth governor of and then-incumbent United States senator representing California) and his wife, Jane, in memory of their only child, Leland Jr. The university admitted its first students in 1891, opening as a coeducational and non-denominational institution. It struggled financially after Leland died in 1893 and again after much of the campus was damaged by the 1906 San Francisco earthquake. Following World War II, university provost Frederick Terman inspired an entrepreneurial culture to build a self-sufficient local industry (later Silicon Valley). In 1951, Stanford Research Park was established in Palo Alto as the world's first university research park. By 2021, the university had 2,288 tenure-line faculty, senior fellows, center fellows, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
1938 Deaths
Events January * January 1 – state-owned enterprise, State-owned railway networks are created by merger, in France (SNCF) and the Netherlands (Nederlandse Spoorwegen – NS). * January 20 – King Farouk of Egypt marries Safinaz Zulficar, who becomes Farida of Egypt, Queen Farida, in Cairo. * January 27 – The Honeymoon Bridge (Niagara Falls), Honeymoon Bridge at Niagara Falls, New York, collapses as a result of an ice jam. February * February 4 ** Adolf Hitler abolishes the War Ministry and creates the Oberkommando der Wehrmacht (High Command of the Armed Forces), giving him direct control of the German military. In addition, he dismisses political and military leaders considered unsympathetic to his philosophy or policies. General Werner von Fritsch is forced to resign as Commander of Chief of the German Army following accusations of homosexuality, and replaced by General Walther von Brauchitsch. Foreign Minister Baron Konstantin von Neurath is dismi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
1883 Births
Events January * January 4 – ''Life (magazine), Life'' magazine is founded in Los Angeles, California, United States. * January 10 – A Newhall House Hotel Fire, fire at the Newhall Hotel in Milwaukee, Wisconsin, United States, kills 73 people. * January 16 – The Pendleton Civil Service Reform Act, establishing the United States civil service, is passed. * January 19 – The first electric lighting system employing overhead wires begins service in Roselle, New Jersey, United States, installed by Thomas Edison. February * February 15 – Tokyo Electrical Lightning Grid, predecessor of Tokyo Electrical Power (TEPCO), one of the largest electrical grids in Asia and the world, is founded in Japan. * February 16 – The ''Ladies' Home Journal'' is published for the first time, in the United States. * February 23 – Alabama becomes the first U.S. state to enact an Competition law, antitrust law. * February 28 – The first vaudeville th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
William Webster Hansen
William is a masculine given name of Germanic origin. It became popular in England after the Norman conquest in 1066,All Things William"Meaning & Origin of the Name"/ref> and remained so throughout the Middle Ages and into the modern era. It is sometimes abbreviated "Wm." Shortened familiar versions in English include Will or Wil, Wills, Willy, Willie, Bill, Billie, and Billy. A common Irish form is Liam. Scottish diminutives include Wull, Willie or Wullie (as in Oor Wullie). Female forms include Willa, Willemina, Wilma and Wilhelmina. Etymology William is related to the German given name ''Wilhelm''. Both ultimately descend from Proto-Germanic ''*Wiljahelmaz'', with a direct cognate also in the Old Norse name ''Vilhjalmr'' and a West Germanic borrowing into Medieval Latin ''Willelmus''. The Proto-Germanic name is a compound of *''wiljô'' "will, wish, desire" and *''helmaz'' "helm, helmet".Hanks, Hardcastle and Hodges, ''Oxford Dictionary of First Names'', Oxford Universi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Radiative Auger Effect
In optics and spectroscopy, the radiative Auger effect is a decay channel of an inner-shell atomic vacancy state, in which an X-ray photon is emitted accompanying simultaneous promotion of an electron into either a bound or a continuum state. Thus the transition energy is shared between the photon and the electron. The effect was first observed by Felix Bloch and Perley Ason Ross, with the initial theoretical explanation by Bloch. Later the effect has also been observed on defects in the solid-state, semiconductor quantum emitters, as well as two-dimensional electron gases. In the latter case, the effect is typically referred to as shake-up. See also *Auger effect The Auger effect (; ) or Meitner-Auger effect is a physical phenomenon in which atoms eject electrons. It occurs when an inner-shell vacancy in an atom is filled by an electron, releasing energy that causes the emission of another electron from a ... * Radiative transition References Atomic physics {{AMO-phys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Compton Scattering
Compton scattering (or the Compton effect) is the quantum theory of high frequency photons scattering following an interaction with a charged particle, usually an electron. Specifically, when the photon hits electrons, it releases loosely bound electrons from the outer valence shells of atoms or molecules. The effect was discovered in 1923 by Arthur Holly Compton while researching the scattering of X-rays by light elements, and earned him the Nobel Prize in Physics in 1927. The Compton effect significantly deviated from dominating classical theories, using both special relativity and quantum mechanics to explain the interaction between high frequency photons and charged particles. Photons can interact with matter at the atomic level (e.g. photoelectric effect and Rayleigh scattering), at the nucleus, or with just an electron. Pair production and the Compton effect occur at the level of the electron. When a high frequency photon scatters due to an interaction with a charged part ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Spectroscopy
Spectroscopy is the field of study that measures and interprets electromagnetic spectra. In narrower contexts, spectroscopy is the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum. Spectroscopy, primarily in the electromagnetic spectrum, is a fundamental exploratory tool in the fields of astronomy, chemistry, materials science, and physics, allowing the composition, physical structure and electronic structure of matter to be investigated at the atomic, molecular and macro scale, and over astronomical distances. Historically, spectroscopy originated as the study of the wavelength dependence of the absorption by gas phase matter of visible light dispersed by a prism. Current applications of spectroscopy include biomedical spectroscopy in the areas of tissue analysis and medical imaging. Matter waves and acoustic waves can also be considered forms of radiative energy, and recently gravitational waves have been associa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Physicist
A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate causes of Phenomenon, phenomena, and usually frame their understanding in mathematical terms. They work across a wide range of Physics#Research fields, research fields, spanning all length scales: from atom, sub-atomic and particle physics, through biological physics, to physical cosmology, cosmological length scales encompassing the universe as a whole. The field generally includes two types of physicists: Experimental physics, experimental physicists who specialize in the observation of natural phenomena and the development and analysis of experiments, and Theoretical physics, theoretical physicists who specialize in mathematical modeling of physical systems to rationalize, explain and predict natural phenomena. Physicists can apply their k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Ross Differential Filter
Ross may refer to: People and fictional characters * Ross (name), including a list of people and fictional characters with the surname or given name Ross, as well as the meaning * Clan Ross, a Highland Scottish clan Places Antarctica * Ross Sea * Ross Ice Shelf * Ross Dependency * Ross Island Ireland *"Ross", a common nickname for County Roscommon * Ross, County Mayo, a townland bordering Moyne Townland * Ross, County Westmeath, a townland in Noughaval civil parish * Diocese of Ross (Ireland), West Cork United Kingdom * Ross, Northumberland, England, a village * Ross, Scottish Borders, a hamlet * Ross-on-Wye, England * Ross, Scotland, a region of Scotland and former earldom * County of Ross, Scotland * Diocese of Ross (Scotland) United States * Ross, Arkansas, an unincorporated community * Ross, California, a town * Ross, Indiana, an unincorporated community * Ross, Iowa, an unincorporated community * Ross, Minnesota, an unincorporated community * Ross, North Dakota, a city ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Matter
In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic particles. In everyday as well as scientific usage, ''matter'' generally includes atoms and anything made up of them, and any particles (or combination of particles) that act as if they have both rest mass and volume. However it does not include massless particles such as photons, or other energy phenomena or waves such as light or heat. Matter exists in various states (also known as phases). These include classical everyday phases such as solid, liquid, and gas – for example water exists as ice, liquid water, and gaseous steam – but other states are possible, including plasma, Bose–Einstein condensates, fermionic condensates, and quark–gluon plasma. Usually atoms can be imagined as a nucleus of protons and neu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
