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Lene Vestergaard Hau
Lene Vestergaard Hau (; born November 13, 1959) is a Danish physicist and educator. She is the Mallinckrodt Professor of Physics and of Applied Physics at Harvard University. In 1999, she led a Harvard University team who, by use of a Bose–Einstein condensate, succeeded in slowing a beam of light to about 17 metres per second, and, in 2001, was able to stop a beam completely. Later work based on these experiments led to the transfer of light to matter, then from matter back into light, a process with important implications for quantum encryption and quantum computing. More recent work has involved research into novel interactions between ultracold atoms and nanoscopic-scale systems. In addition to teaching physics and applied physics, she has taught Energy Science at Harvard, involving photovoltaic cells, nuclear power, batteries, and photosynthesis. In addition to her own experiments and research, she is often invited to speak at international conferences, and is involved i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vejle
Vejle () is a city in Denmark, in the southeast of the Jutland Peninsula at the head of Vejle Fjord, where the Vejle River and Grejs River and their valleys converge. It is the site of the councils of Vejle Municipality ('' kommune'') and the Region of Southern Denmark. The city has a population of 60,231 () making it the ninth largest city in Denmark. Vejle Municipality has a population of 119,007 () making it the fifth largest municipality in Denmark. The city is part of the Triangle Region, which includes the neighbouring cities of Kolding and Fredericia and it is located 110 kilometres (68 miles) north of Germany. Vejle is most known for its forested hills, fjord, harbour, shopping, pedestrian mall, and windmill. History The word "Vejle" derives from the Old Danish word ''wæthel'', meaning "ford" or "wading place" due to its location at a busy crossing over Vejle River. During Viking times, the wetlands around Vejle had to be crossed at the Ravning Bridge, a nearly hal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
George Ledlie Prize
The George Ledlie Prize is awarded by the "President and Fellows of Harvard College" for contributions to science. George Ledlie George Hees Ledlie was born at Palatine Bridge, New York and attended private schools and colleges to prepare for Harvard, from where he graduated in 1884. In 1909 he reported to Harvard in a hand-written note that his full name had become George Ledlie – thus dropping his middle name Hees, the maiden name of his mother. Ledlie was a St. Louis and New York newspaper executive and an associate of publisher Joseph Pulitzer. George (Hees) Ledlie died on 16 April 1927, and the Harvard George Ledlie Prize became a bequest that year. As a philanthropist, Ledlie donated an amount to Harvard, with the following conditions: "Bequest of George Ledlie, 1884, the net income to be paid not oftener than once in every two years as a prize to a person in any way connected with said University, who, in the judgement of said University since the last awarding of the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copenhagen
Copenhagen ( or .; da, København ) is the capital and most populous city of Denmark, with a proper population of around 815.000 in the last quarter of 2022; and some 1.370,000 in the urban area; and the wider Copenhagen metropolitan area has 2,057,142 people. Copenhagen is on the islands of Zealand and Amager, separated from Malmö, Sweden, by the Øresund strait. The Øresund Bridge connects the two cities by rail and road. Originally a Viking fishing village established in the 10th century in the vicinity of what is now Gammel Strand, Copenhagen became the capital of Denmark in the early 15th century. Beginning in the 17th century, it consolidated its position as a regional centre of power with its institutions, defences, and armed forces. During the Renaissance the city served as the de facto capital of the Kalmar Union, being the seat of monarchy, governing the majority of the present day Nordic region in a personal union with Sweden and Norway ruled by the Danis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosynthesis
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in carbohydrate molecules, such as sugars and starches, which are synthesized from carbon dioxide and water – hence the name ''photosynthesis'', from the Greek ''phōs'' (), "light", and ''synthesis'' (), "putting together". Most plants, algae, and cyanobacteria perform photosynthesis; such organisms are called photoautotrophs. Photosynthesis is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and supplies most of the energy necessary for life on Earth. Although photosynthesis is performed differently by different species, the process always begins when energy from light is absorbed by proteins called reaction centers that contain green chlorophyll (and other colored) pigments/chromoph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Battery (electricity)
An electric battery is a source of electric power consisting of one or more electrochemical cells with external connections for powering electrical devices. When a battery is supplying power, its positive terminal is the cathode and its negative terminal is the anode. The terminal marked negative is the source of electrons that will flow through an external electric circuit to the positive terminal. When a battery is connected to an external electric load, a redox reaction converts high-energy reactants to lower-energy products, and the free-energy difference is delivered to the external circuit as electrical energy. Historically the term "battery" specifically referred to a device composed of multiple cells; however, the usage has evolved to include devices composed of a single cell. Primary (single-use or "disposable") batteries are used once and discarded, as the electrode materials are irreversibly changed during discharge; a common example is the alkaline battery used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Power
Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions. Presently, the vast majority of electricity from nuclear power is produced by nuclear ''fission'' of uranium and plutonium in nuclear power plants. Nuclear ''decay'' processes are used in niche applications such as radioisotope thermoelectric generators in some space probes such as ''Voyager 2''. Generating electricity from fusion power, ''fusion'' power remains the focus of international research. Most nuclear power plants use thermal reactors with enriched uranium in a Nuclear fuel cycle#Once-through nuclear fuel cycle, once-through fuel cycle. Fuel is removed when the percentage of neutron poison, neutron absorbing atoms becomes so large that a nuclear chain reaction, chain reaction can no longer be sustained, typically three years. It is then cooled for several years in on-site spent fuel pools before being tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photovoltaic Cell
A solar cell, or photovoltaic cell, is an electronic device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physics, physical and Chemical substance, chemical phenomenon.Solar Cells chemistryexplained.com It is a form of photoelectric cell, defined as a device whose electrical characteristics, such as Electric current, current, voltage, or Electrical resistance and conductance, resistance, vary when exposed to light. Individual solar cell devices are often the electrical building blocks of solar panel, photovoltaic modules, known colloquially as solar panels. The common single junction silicon solar cell can produce a maximum open-circuit voltage of approximately 0.5 volts to 0.6volts. Solar cells are described as being Photovoltaics, photovoltaic, irrespe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanoscopic Scale
The nanoscopic scale (or nanoscale) usually refers to structures with a length scale applicable to nanotechnology, usually cited as 1–100 nanometers (nm). A nanometer is a billionth of a meter. The nanoscopic scale is (roughly speaking) a lower bound to the mesoscopic scale for most solids. For technical purposes, the nanoscopic scale is the size at which fluctuations in the averaged properties (due to the motion and behavior of individual particles) begin to have a significant effect (often a few percent) on the behavior of a system, and must be taken into account in its analysis. The nanoscopic scale is sometimes marked as the point where the properties of a material change; above this point, the properties of a material are caused by 'bulk' or 'volume' effects, namely which atoms are present, how they are bonded, and in what ratios. Below this point, the properties of a material change, and while the type of atoms present and their relative orientations are still importan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultracold Atom
Ultracold atoms are atoms that are maintained at temperatures close to 0 kelvin (absolute zero), typically below several tens of microkelvin (µK). At these temperatures the atom's quantum-mechanical properties become important. To reach such low temperatures, a combination of several techniques typically has to be used. First, atoms are usually trapped and pre-cooled via laser cooling in a magneto-optical trap. To reach the lowest possible temperature, further cooling is performed using evaporative cooling in a magnetic or optical trap. Several Nobel prizes in physics are related to the development of the techniques to manipulate quantum properties of individual atoms (e.g. 1995-1997, 2001, 2005, 2012, 2017). Experiments with ultracold atoms study a variety of phenomena, including quantum phase transitions, Bose–Einstein condensation (BEC), bosonic superfluidity, quantum magnetism, many-body spin dynamics, Efimov states, Bardeen–Cooper–Schrieffer (BCS) superfluidity and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Computing
Quantum computing is a type of computation whose operations can harness the phenomena of quantum mechanics, such as superposition, interference, and entanglement. Devices that perform quantum computations are known as quantum computers. Though current quantum computers may be too small to outperform usual (classical) computers for practical applications, larger realizations are believed to be capable of solving certain computational problems, such as integer factorization (which underlies RSA encryption), substantially faster than classical computers. The study of quantum computing is a subfield of quantum information science. There are several models of quantum computation with the most widely used being quantum circuits. Other models include the quantum Turing machine, quantum annealing, and adiabatic quantum computation. Most models are based on the quantum bit, or "qubit", which is somewhat analogous to the bit in classical computation. A qubit can be in a 1 or 0 quantum s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Encryption
Quantum key distribution (QKD) is a secure communication method which implements a cryptographic protocol involving components of quantum mechanics. It enables two parties to produce a shared random secret key known only to them, which can then be used to encrypt and decrypt messages. It is often incorrectly called quantum cryptography, as it is the best-known example of a quantum cryptographic task. An important and unique property of quantum key distribution is the ability of the two communicating users to detect the presence of any third party trying to gain knowledge of the key. This results from a fundamental aspect of quantum mechanics: the process of measuring a quantum system in general disturbs the system. A third party trying to eavesdrop on the key must in some way measure it, thus introducing detectable anomalies. By using quantum superpositions or quantum entanglement and transmitting information in quantum states, a communication system can be implemented tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metre Per Second
The metre per second is the unit of both speed (a scalar (physics), scalar quantity) and velocity (a Vector (mathematics and physics), vector quantity, which has direction and magnitude) in the International System of Units (SI), equal to the speed of a body covering a distance of one metre in a time of one second. The International System of Units, SI unit symbols are m/s, m·s−1, m s−1, or . Sometimes it is abbreviated as "mps". Conversions is equivalent to: : = 3.6 kilometres per hour, km/h (exactly) : ≈ 3.2808 feet per second (approximately) : ≈ 2.2369 miles per hour (approximately) : ≈ 1.9438 knot (unit), knots (approximately) 1 feet per second, foot per second = (exactly) 1 miles per hour, mile per hour = (exactly) 1 kilometres per hour, km/h = (exactly) Relation to other measures The benz, named in honour of Karl Benz, has been proposed as a name for one metre per second. Although it has seen some support as a practical unit, primarily from German ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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