21 résultats pour "quantum"
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Quantum Theory
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INTRODUCTION
Quantum Theory, in physics, description of the particles that make up matter and how they interact with each other and with energy.
electron in the same way a particle with momentum would: It bumps the electron and changes the electron’s path. The light is also affected by the collision as though itwere a particle, in that its energy and momentum changes. Momentum is a quantity that can be defined for all particles. For light particles, or photons, momentum depends on the frequency, or color, of the photon, which in turndepends on the photon’s energy. The energy of a photon is equal to a constant number, called Planck’s cons...
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Periodic Law - chemistry.
VI QUANTUM THEORY With the development of the quantum theory and its application to atomic structure by the Danish physicist Niels Bohr and other scientists, most of the detailedfeatures of the periodic table have found a ready explanation. Every electron is characterized by four quantum numbers that designate its orbital motion in space. Bymeans of the selection rules governing these quantum numbers and the exclusion principle of Wolfgang Pauli, which states that two electrons in the same ato...
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Bohr, Niels
in Bohr's writings. The central claim of Bohr's philosophy after EPR is the indispensability of classical concepts, supplemented by ordinary language, for unambiguous communication of experimental results. Unambiguous description presupposes a strict separation between the observed object and the observing subject. This is possible only at the classical level, where the quantum of action can be neglected. Classical concepts, guided by complementarity in different experimental arrangements,...
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Jung and Pauli: A Meeting of Rare Minds
JUNG AND PAU\bI A Meeting \bf Rare Minds BY BEVERLEY ZABR\bSK\bE Readers of the Swiss psychiatrist C. G. Jungare more familiar with Wolfgang Pauli’s unconscious than with his waking life and achievement. Through Jung’s Psych\bl\bgy and Alchemy—an exposition of “the problem of individuation” and “normal development . . . in a highly intelligent person”—depth psychologists have known the Nobel laureate’s dreams, not his professional genius. Meanwhile, the scientists who continue Pauli’s pur- sui...
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Activité corrigé quantum - Partie 1 : L’effet photoélectrique
Act doc 9 – OS4 – Lumière ! Partie 1 : L’effet photoélectrique Doc 1 : L’expérience de Hertz En 1887, Hertz observe l'émission d'électrons par une plaque métallique alors qu’elle est exposée à la lumière ultraviolette, sans pouvoir l'expliquer. Les observations de cet effet entrent en conflit avec la théorie ondulatoire de la lumière de l’époque car on constate que des électrons sont émis seulement si la fréquence de radiation dépasse une certaine valeur seuil et ils sont alors...
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O quantum est in rebus inane !
0 quantum est in rebus inane ! Combien la réalité est vide ! li s'agit de la fin du premier vers de la première satire de Perse (0 curas J,ominum, o quantum est in rebus inane !), qui devint ensuite un énoncé gnomique à part entière et prit la même signification que Vanitas vaniratum (n. 1561 ). L'expression fut reprise par saint Jérôme (Tracta1us in l/X Psalmos, 93), puis citée par plusieurs auteurs médiévaux (cf. par exemple Paschase Radbert, De Passione Sanctorum Rujini et Va/erii, Pl 120, 15...
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Relativity
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INTRODUCTION
Albert Einstein
In 1905 German-born American physicist Albert Einstein published his first paper outlining the theory of relativity.
in calculating very large distances or very large aggregations of matter. As the quantum theory applies to the very small, so the relativity theory applies to the verylarge. Until 1887 no flaw had appeared in the rapidly developing body of classical physics. In that year, the Michelson-Morley experiment, named after the American physicistAlbert Michelson and the American chemist Edward Williams Morley, was performed. It was an attempt to determine the rate of the motion of the earth through t...
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Karl Marx: Das Kapital - Anthologie.
Werts messen? Durch das Quantum der in ihm enthaltenen „wertbildenden Substanz”, der Arbeit. Die Quantität der Arbeit selbst mißt sich an ihrer Zeitdauer, unddie Arbeitszeit besitzt wieder ihren Maßstab an bestimmten Zeitteilen, wie Stunde, Tag usw. Karl Marx: Das Kapital. Kritik der politischen Ökonomie. Band I: Der Produktionsprozeß des Kapitals. S. 17ff. Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. Alle Rechte vorbehalten.
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Thermodynamics
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INTRODUCTION
Thermodynamics, field of physics that describes and correlates the physical properties of macroscopic systems of matter and energy.
Carnot EngineThe idealized Carnot engine was envisioned by the French physicist Nicolas Léonard Sadi Carnot, who lived during theearly 19th century. The Carnot engine is theoretically perfect, that is, it converts the maximum amount of energy intomechanical work. Carnot showed that the efficiency of any engine depends on the difference between the highest andlowest temperatures reached during one cycle. The greater the difference, the greater the efficiency. An automobileengine, for example, wou...
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Magnetism
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INTRODUCTION
Magnetism, an aspect of electromagnetism, one of the fundamental forces of nature.
the French physicist Paul Langevin produced a theory regarding the temperature dependence of the magnetic properties of paramagnets (discussed below), which wasbased on the atomic structure of matter. This theory is an early example of the description of large-scale properties in terms of the properties of electrons and atoms.Langevin's theory was subsequently expanded by the French physicist Pierre Ernst Weiss, who postulated the existence of an internal, “molecular” magnetic field inmaterials...
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Cosmology - astronomy.
In 1917 American scientist Harlow Shapley measured the distance to several groups of stars known as globular clusters. He measured these distances by using amethod developed in 1912 by American astronomer Henrietta Leavitt. Leavitt’s method relates distance to variations in brightness of Cepheid variables, a class of starsthat vary periodically in brightness. Shapley’s distance measurements showed that the clusters were centered around a point far from the Sun. The arrangement of theclusters was...
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Chemistry - chemistry.
parts of oxygen by weight, which is a ratio of about 1 to 8, regardless of whether the water came from the Mississippi River or the ice of Antarctica. In other words, acompound has a definite, invariable composition, always containing the same elements in the same proportions by weight; this is the law of definite proportions. Many elements combine in more than one ratio, giving different compounds. In addition to forming water, hydrogen and oxygen also form hydrogen peroxide.Hydrogen peroxide h...
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Crescit amor nummi, quantum ipsa pecunia crevit
Crescit amor nummi, quantum ipsa pecunia crevit L'amour des écus grandit autant que se multiplie l'argent Cette maxime, souvent reprise - y compris avec le présent crescit à la place de crevit - est citée à partir du Moyen-Age (cf. l'apparat de Walther 3731 : parmi les auteurs les plus anciens, cf. Pseudo-Augustin, Sermones, Pl 39, 2154 ; Césaire d'Arles, Sermones, 222, 5 ; saint Colomban, Ad Hunaldum, 54 [PL 80 , 286b] ; Isidore de Séville, Origines, 1, 36,...
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7. Quantum 111utat11s ab illo !
Combien il est différent de celui qu'il était !
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Le fantôme d'Hector apparait...
7. Quantum 111utat11s ab illo ! Combien il est différent de celui qu'il était ! .. Le fantôme d'Hector apparait à Enée au deuxième chant de l'Enéide • (vv. 274 sq.), sous le même aspect que...
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324. Quantum oculis, animo tam procu/ ibit amor
Tu seras aussi loin de mon cœur que de mes yeux
c·ctte...
324. Quantum oculis, animo tam procu/ ibit amor Tu seras aussi loin de mon cœur que de mes yeux c·ctte expression est empruntée à Properce (3, 21, 10) mais le topos revient dans d'autres passages de cet auteur (cf. l , 2, 11), de même que chez Ovide (Ars amatoria, 2,358); Venance Fortunat (7, 12, 71) et saint...
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Bridgman, Percy William
physicist does . What is real is what is meaningful and 'we mean by any concept nothing more than a set of operations; the concept is synonymous with the corresponding set of operations' . Each operation thus defines a separate concept. For Bridgman the measuring operations were the only permanent physical entities. Bridgman saw operationalism as a method for analysis - for sorting out what was and was not real among scientific assertions - and not a criterion for regimenting or demarc...
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Atom
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INTRODUCTION
Water Molecule
A water molecule consists of an oxygen atom and two hydrogen atoms, which are attached at an angle of 105°.
spontaneously break apart and change, or decay, into other atoms. Unlike electrons, which are fundamental particles, protons and neutrons are made up of other, smaller particles called quarks. Physicists know of six different quarks.Neutrons and protons are made up of up quarks and down quarks —two of the six different kinds of quarks. The fanciful names of quarks have nothing to do with their properties; the names are simply labels to distinguish one quark from another. Quarks are unique amo...
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Atom - chemistry.
Atoms have several properties that help distinguish one type of atom from another and determine how atoms change under certain conditions. A Atomic Number Each element has a unique number of protons in its atoms. This number is called the atomic number (abbreviated Z). Because atoms are normally electrically neutral,the atomic number also specifies how many electrons an atom will have. The number of electrons, in turn, determines many of the chemical and physical properties ofthe atom. The ligh...
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Physics
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INTRODUCTION
Physics, major science, dealing with the fundamental constituents of the universe, the forces they exert on one another, and the results produced by these forces.
Starting about 1665, at the age of 23, Newton enunciated the principles of mechanics, formulated the law of universal gravitation, separated white light into colors,proposed a theory for the propagation of light, and invented differential and integral calculus. Newton's contributions covered an enormous range of naturalphenomena: He was thus able to show that not only Kepler's laws of planetary motion but also Galileo's discoveries of falling bodies follow a combination of his ownsecond law of m...
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Laser.
their atoms into laser light. Consequently, they are the most powerful continuous wave (CW) lasers—that is, lasers that emit light continuously rather than in pulses. C Liquid Lasers The most common liquid laser media are inorganic dyes contained in glass vessels. They are pumped by intense flash lamps in a pulse mode or by a separate gas laserin the continuous wave mode. Some dye lasers are tunable, meaning that the color of the laser light they emit can be adjusted with the help of a prism lo...