|
Friedrich Carl Alwin Pockels
Friedrich Carl Alwin Pockels (18 June 1865 – 29 August 1913) was a German physicist. He was born in Italy to Captain Theodore Pockels and Alwine Becker. He obtained a doctorate from the University of Göttingen in 1888, and from 1900 to 1913 he was professor of theoretical physics at the University of Heidelberg. In 1893 he discovered that a steady electric field applied to certain birefringent materials causes the refractive index to vary, approximately in proportion to the strength of the field. The coefficient of proportionality is of the order of to . This phenomenon is now called the Pockels effect. His sister Agnes Pockels (1862–1935) was a pioneer in chemistry. See also *Photoelasticity Photoelasticity describes changes in the optical properties of a material under mechanical deformation. It is a property of all dielectric media and is often used to experimentally determine the stress distribution in a material, where it gives ... 19th-century German phys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Italy
Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical region. Italy is also considered part of Western Europe, and shares land borders with France, Switzerland, Austria, Slovenia and the enclaved microstates of Vatican City and San Marino. It has a territorial exclave in Switzerland, Campione. Italy covers an area of , with a population of over 60 million. It is the third-most populous member state of the European Union, the sixth-most populous country in Europe, and the tenth-largest country in the continent by land area. Italy's capital and largest city is Rome. Italy was the native place of many civilizations such as the Italic peoples and the Etruscans, while due to its central geographic location in Southern Europe and the Mediterranean, the country has also historically been home ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agnes Pockels
Agnes Luise Wilhelmine Pockels (14 February 1862 – 21 November 1935) was a German chemist whose research was fundamental in establishing the modern discipline known as surface science, which describes the properties of liquid and solid surfaces and interfaces. Pockels became interested in fundamental research in surface science through observations of soaps and soapy water in her own home while washing dishes. She devised a surface film balance technique to study the behavior of molecules such as soaps and surfactants at air-liquid interfaces. From these studies, Pockels defined the "Pockels Point" which is the minimum area that a single molecule can occupy in monomolecular films. Pockels was an autodidact. She was not a paid, professional scientist and had no institutional affiliation and so is an example of a citizen scientist. Early life and education Pockels was born in Venice, Italy, in 1862. At the time, Venice was under Austrian rule, and Pockels' father served ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Göttingen Alumni
A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. Universities typically offer both undergraduate and postgraduate programs. In the United States, the designation is reserved for colleges that have a graduate school. The word ''university'' is derived from the Latin ''universitas magistrorum et scholarium'', which roughly means "community of teachers and scholars". The first universities were created in Europe by Catholic Church monks. The University of Bologna (''Università di Bologna''), founded in 1088, is the first university in the sense of: *Being a high degree-awarding institute. *Having independence from the ecclesiastic schools, although conducted by both clergy and non-clergy. *Using the word ''universitas'' (which was coined at its foundation). *Issuing secular and non-secular degrees: grammar, rhetoric, logic, theology, canon law, notarial law.Hunt Janin: "The university i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Technical University Of Braunschweig Alumni
Technical may refer to: * Technical (vehicle), an improvised fighting vehicle * Technical analysis, a discipline for forecasting the future direction of prices through the study of past market data * Technical drawing, showing how something is constructed or functions (also known as drafting) * Technical file, set of technical drawings * Technical death metal, a subgenre of death metal that focuses on complex rhythms, riffs, and song structures * Technical foul, an infraction of the rules in basketball usually concerning unsportsmanlike non-contact behavior * Technical rehearsal for a performance, often simply referred to as a technical * Technical support, a range of services providing assistance with technology products * Vocational education, often known as technical education * Legal technicality, an aspect of law See also * Lego Technic, a line of Lego toys * Tech (other) * Technicals (other) * Technics (other) * Technique (other) Te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1913 Deaths
Events January * January 5 РFirst Balkan War: Battle of Lemnos РGreek admiral Pavlos Kountouriotis forces the Turkish fleet to retreat to its base within the Dardanelles, from which it will not venture for the rest of the war. * January 13 РEdward Carson founds the (first) Ulster Volunteer Force, by unifying several existing loyalist militias to resist home rule for Ireland. * January 23 Р1913 Ottoman coup d'̩tat: Ismail Enver comes to power. * January РStalin (whose first article using this name is published this month) travels to Vienna to carry out research. Until he leaves on February 16 the city is home simultaneously to him, Hitler, Trotsky and Tito alongside Berg, Freud and Jung and Ludwig and Paul Wittgenstein. February * February 1 РNew York City's Grand Central Terminal, having been rebuilt, reopens as the world's largest railroad station. * February 3 РThe 16th Amendment to the United States Cons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1865 Births
Events January–March * January 4 – The New York Stock Exchange opens its first permanent headquarters at 10-12 Broad near Wall Street, in New York City. * January 13 – American Civil War : Second Battle of Fort Fisher: United States forces launch a major amphibious assault against the last seaport held by the Confederates, Fort Fisher, North Carolina. * January 15 – American Civil War: United States forces capture Fort Fisher. * January 31 ** The Thirteenth Amendment to the United States Constitution (conditional prohibition of slavery and involuntary servitude) passes narrowly, in the House of Representatives. ** American Civil War: Confederate General Robert E. Lee becomes general-in-chief. * February ** American Civil War: Columbia, South Carolina burns, as Confederate forces flee from advancing Union forces. * February 3 – American Civil War : Hampton Roads Conference: Union and Confederate leaders discuss peace terms. * February 8 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
19th-century German Physicists
The 19th (nineteenth) century began on 1 January 1801 ( MDCCCI), and ended on 31 December 1900 ( MCM). The 19th century was the ninth century of the 2nd millennium. The 19th century was characterized by vast social upheaval. Slavery was abolished in much of Europe and the Americas. The First Industrial Revolution, though it began in the late 18th century, expanding beyond its British homeland for the first time during this century, particularly remaking the economies and societies of the Low Countries, the Rhineland, Northern Italy, and the Northeastern United States. A few decades later, the Second Industrial Revolution led to ever more massive urbanization and much higher levels of productivity, profit, and prosperity, a pattern that continued into the 20th century. The Islamic gunpowder empires fell into decline and European imperialism brought much of South Asia, Southeast Asia, and almost all of Africa under colonial rule. It was also marked by the collapse of the large S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoelasticity
Photoelasticity describes changes in the optical properties of a material under mechanical deformation. It is a property of all dielectric media and is often used to experimentally determine the stress distribution in a material, where it gives a picture of stress distributions around discontinuities in materials. Photoelastic experiments (also informally referred to as ''photoelasticity'') are an important tool for determining critical stress points in a material, and are used for determining stress concentration in irregular geometries. History The photoelastic phenomenon was first discovered by the Scottish physicist David Brewster, who immediately recognized it as stress-induced birefringence. That diagnosis was confirmed in a direct refraction experiment by Augustin-Jean Fresnel.A. Fresnel, "Note sur la double réfraction du verre comprimé" (read 16 September 1822), ''Annales de Chimie et de Physique'', Ser. 2, vol. 20, pp. 376–83 (nominally f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pockels Effect
The Pockels effect or Pockels electro-optic effect, named after Friedrich Carl Alwin Pockels (who studied the effect in 1893), changes or produces birefringence in an optical medium induced by an electric field. In the Pockels effect, also known as the linear electro-optic effect, the birefringence is proportional to the electric field. In the Kerr effect, the refractive index change (birefringence) is proportional to the square of the field. The Pockels effect occurs only in crystals that lack inversion symmetry, such as KH2PO4 (KDP), KD2PO4 (KD*P or DKDP), lithium niobate (LiNbO3), and in other non-centrosymmetric media such as electric-field poled polymers or glasses. The electro-optic properties of materials like KDP and its isomorphs that exhibits that Pockels effect has been extensively studied over the years to allow accurate models for simulations. Pockels cells Pockels cells are voltage-controlled wave plates. The Pockels effect is the basis of the operation of Pockels ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Göttingen
The University of Göttingen, officially the Georg August University of Göttingen, (german: Georg-August-Universität Göttingen, known informally as Georgia Augusta) is a public research university in the city of Göttingen, Germany. Founded in 1734 by George II, King of Great Britain and Elector of Hanover, and starting classes in 1737, the Georgia Augusta was conceived to promote the ideals of the Enlightenment. It is the oldest university in the state of Lower Saxony and the largest in student enrollment, which stands at around 31,600. Home to many noted figures, it represents one of Germany's historic and traditional institutions. According to an official exhibition held by the University of Göttingen in 2002, 44 Nobel Prize winners had been affiliated with the University of Göttingen as alumni, faculty members or researchers by that year alone. The University of Göttingen was previously supported by the German Universities Excellence Initiative, holds memberships ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volt
The volt (symbol: V) is the unit of electric potential, electric potential difference (voltage), and electromotive force in the International System of Units (SI). It is named after the Italian physicist Alessandro Volta (1745–1827). Definition One volt is defined as the electric potential between two points of a conducting wire when an electric current of one ampere dissipates one watt of power between those points. Equivalently, it is the potential difference between two points that will impart one joule of energy per coulomb of charge that passes through it. It can be expressed in terms of SI base units ( m, kg, second, s, and ampere, A) as : \text = \frac = \frac = \frac. It can also be expressed as amperes times ohms (current times resistance, Ohm's law), webers per second (magnetic flux per time), watts per ampere (power per current), or joules per coulomb (energy per charge), which is also equivalent to electronvolts per elementary charge: : \text = \tex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refractive Index
In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium. The refractive index determines how much the path of light is bent, or refracted, when entering a material. This is described by Snell's law of refraction, , where ''θ''1 and ''θ''2 are the angle of incidence and angle of refraction, respectively, of a ray crossing the interface between two media with refractive indices ''n''1 and ''n''2. The refractive indices also determine the amount of light that is reflected when reaching the interface, as well as the critical angle for total internal reflection, their intensity ( Fresnel's equations) and Brewster's angle. The refractive index can be seen as the factor by which the speed and the wavelength of the radiation are reduced with respect to their vacuum values: the speed of light in a medium is , and similarly the wavelength in that medium is , where ''Π... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_-_09.JPG "Click for more on -> University Of Göttingen Alumni")
