|
Leiden Scale
The Leiden scale (°L or ÐL) is a temperature scale that was used to calibrate low-temperature indirect measurements in the early 20th century, by providing conventional values (in kelvins, then termed "degrees Kelvin") of helium vapour pressure. The scale dates back at around 1894, when Heike Kamerlingh Onnes established his cryogenics laboratory in Leiden, Netherlands. It was used below −183 °C, the starting point of the International Temperature Scale in the 1930s (Awbery 1934). The boiling points of standard hydrogen (−253 °C), consisting of 75% orthohydrogen and 25% parahydrogen, and oxygen (−183 °C) were used as fixed points, corresponding to zero and 70 on the scale respectively. See also * Outline of metrology and measurement References *Berman, A.; Zemansky, M. W.; and Boorse, H. A.; Normal and Superconducting Heat Capacities of Lanthanum', Physical Review, Vol. 109, No. 1 (January 1958), pp. 70–76. Quote: :"The 1955 Leiden scale13 was u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scale Of Temperature
Scale of temperature is a methodology of calibrating the physical quantity temperature in metrology. Empirical scales measure temperature in relation to convenient and stable parameters or reference points, such as the freezing and boiling point of water. Absolute temperature is based on thermodynamic principles: using the lowest possible temperature as the zero point, and selecting a convenient incremental unit. Celsius, Kelvin, and Fahrenheit are common temperature scales. Other scales used throughout history include Rankine, Rømer, Newton, Delisle, Réaumur, Gas mark, Leiden, and Wedgwood. Technical definition The zeroth law of thermodynamics describes thermal equilibrium between thermodynamic systems in form of an equivalence relation. Accordingly, the set of all thermal systems may be divided into a quotient set of equivalence classes, denoted as M, where any element of M collects all systems that are in thermal equilibrium with one another. If the set M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kelvin
The kelvin (symbol: K) is the base unit for temperature in the International System of Units (SI). The Kelvin scale is an absolute temperature scale that starts at the lowest possible temperature (absolute zero), taken to be 0 K. By definition, the Celsius scale (symbol °C) and the Kelvin scale have the exact same magnitude; that is, a rise of 1 K is equal to a rise of 1 °C and vice versa, and any temperature in degrees Celsius can be converted to kelvin by adding 273.15. The 19th century British scientist Lord Kelvin first developed and proposed the scale. It was often called the "absolute Celsius" scale in the early 20th century. The kelvin was formally added to the International System of Units in 1954, defining 273.16 K to be the triple point of water. The Celsius, Fahrenheit, and Rankine scales were redefined in terms of the Kelvin scale using this definition. The 2019 revision of the SI now defines the kelvin in terms of energy by setting the Bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helium
Helium (from ) is a chemical element; it has chemical symbol, symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert gas, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling point is the lowest among all the Chemical element, elements, and it does not have a melting point at standard pressures. It is the second-lightest and second-most Abundance of the chemical elements, abundant element in the observable universe, after hydrogen. It is present at about 24% of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined. Its abundance is similar to this in both the Sun and Jupiter, because of the very high nuclear binding energy (per nucleon) of helium-4 with respect to the next three elements after helium. This helium-4 binding energy also accounts for why it is a product of both nuclear fusion and radioactive decay. The most common isotope of helium in the universe is helium-4, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vapour Pressure
Vapor pressure or equilibrium vapor pressure is the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system. The equilibrium vapor pressure is an indication of a liquid's thermodynamic tendency to evaporate. It relates to the balance of particles escaping from the liquid (or solid) in equilibrium with those in a coexisting vapor phase. A substance with a high vapor pressure at normal temperatures is often referred to as '' volatile''. The pressure exhibited by vapor present above a liquid surface is known as vapor pressure. As the temperature of a liquid increases, the attractive interactions between liquid molecules become less significant in comparison to the entropy of those molecules in the gas phase, increasing the vapor pressure. Thus, liquids with strong intermolecular interactions are likely to have smaller vapor pressures, with the reverse true for weaker interactions. The vapor p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heike Kamerlingh Onnes
Heike Kamerlingh Onnes (; 21 September 1853 – 21 February 1926) was a Dutch Experimental physics, experimental physicist. After studying in Groningen and Heidelberg, he became Professor of Experimental Physics at Leiden University, where he taught from 1882 to 1923. In 1904, he established a cryogenics laboratory where he exploited the Hampson–Linde cycle to investigate how materials behave when cooled to nearly absolute zero. In 1908, he became the first to liquefaction of gases, liquefy helium, cooling it to near 1.5 kelvin, at the time the coldest temperature achieved on earth. For this research, he was awarded the Nobel Prize in Physics in 1913. Using liquid helium to investigate the electrical conductivity of solid mercury (element), mercury, he found in 1911 that at 4.2 K its electrical resistance vanishes, thus discovering superconductivity. Early life Kamerlingh Onnes was born in Groningen, Netherlands. His father, Harm Kamerlingh Onnes, was a brickworks owner. His ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryogenics
In physics, cryogenics is the production and behaviour of materials at very low temperatures. The 13th International Institute of Refrigeration's (IIR) International Congress of Refrigeration (held in Washington, DC in 1971) endorsed a universal definition of "cryogenics" and "cryogenic" by accepting a threshold of to distinguish these terms from conventional refrigeration. This is a logical dividing line, since the normal boiling points of the so-called permanent gases (such as helium, hydrogen, neon, nitrogen, oxygen, and normal air) lie below 120 K, while the Freon refrigerants, hydrocarbons, and other common refrigerants have boiling points above 120 K. Discovery of superconducting materials with critical temperatures significantly above the boiling point of nitrogen has provided new interest in reliable, low-cost methods of producing high-temperature cryogenic refrigeration. The term "high temperature cryogenic" describes temperatures ranging from above the boili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leiden
Leiden ( ; ; in English language, English and Archaism, archaic Dutch language, Dutch also Leyden) is a List of cities in the Netherlands by province, city and List of municipalities of the Netherlands, municipality in the Provinces of the Netherlands, province of South Holland, Netherlands. The municipality of Leiden has a population of 127,046 (31 January 2023), but the city forms one densely connected agglomeration with its suburbs Oegstgeest, Leiderdorp, Voorschoten and Zoeterwoude with 215,602 inhabitants. The Statistics Netherlands, Netherlands Central Bureau of Statistics (CBS) further includes Katwijk in the agglomeration which makes the total population of the Leiden urban agglomeration 282,207 and in the larger Leiden urban area also Teylingen, Noordwijk, and Noordwijkerhout are included with in total 365,913 inhabitants. Leiden is located on the Oude Rijn (Utrecht and South Holland), Oude Rijn, at a distance of some from The Hague to its south and some from Amsterdam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Netherlands
, Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Netherlands. The Netherlands consists of Provinces of the Netherlands, twelve provinces; it borders Germany to the east and Belgium to the south, with a North Sea coastline to the north and west. It shares Maritime boundary, maritime borders with the United Kingdom, Germany, and Belgium. The official language is Dutch language, Dutch, with West Frisian language, West Frisian as a secondary official language in the province of Friesland. Dutch, English_language, English, and Papiamento are official in the Caribbean Netherlands, Caribbean territories. The people who are from the Netherlands is often referred to as Dutch people, Dutch Ethnicity, Ethnicity group, not to be confused by the language. ''Netherlands'' literally means "lower countries" i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Temperature Scale
The International Temperature Scale of 1990 (ITS-90) is an equipment calibration standard specified by the International Committee of Weights and Measures (CIPM) for making measurements on the Kelvin and Celsius temperature scales. It is an approximation of thermodynamic temperature that facilitates the comparability and compatibility of temperature measurements internationally. It defines fourteen calibration points ranging from to ( to ) and is subdivided into multiple temperature ranges which overlap in some instances. ITS-90 is the most recent of a series of International Temperature Scales adopted by the CIPM since 1927. Adopted at the 1989 General Conference on Weights and Measures, it supersedes the International Practical Temperature Scale of 1968 (amended edition of 1975) and the 1976 "Provisional 0.5 K to 30 K Temperature Scale". The CCT has also published several online guidebooks to aid realisations of the ITS-90. The lowest temperature covered by the ITS-90 is 0.6 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen
Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter. Under standard conditions, hydrogen is a gas of diatomic molecules with the chemical formula, formula , called dihydrogen, or sometimes hydrogen gas, molecular hydrogen, or simply hydrogen. Dihydrogen is colorless, odorless, non-toxic, and highly combustible. Stars, including the Sun, mainly consist of hydrogen in a plasma state, while on Earth, hydrogen is found as the gas (dihydrogen) and in molecular forms, such as in water and organic compounds. The most common isotope of hydrogen (H) consists of one proton, one electron, and no neutrons. Hydrogen gas was first produced artificially in the 17th century by the reaction of acids with metals. Henry Cavendish, in 1766–1781, identified hydrogen gas as a distinct substance and discovere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen
Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), nonmetal, and a potent oxidizing agent that readily forms oxides with most elements as well as with other chemical compound, compounds. Oxygen is abundance of elements in Earth's crust, the most abundant element in Earth's crust, making up almost half of the Earth's crust in the form of various oxides such as water, carbon dioxide, iron oxides and silicates.Atkins, P.; Jones, L.; Laverman, L. (2016).''Chemical Principles'', 7th edition. Freeman. It is abundance of chemical elements, the third-most abundant element in the universe after hydrogen and helium. At standard temperature and pressure, two oxygen atoms will chemical bond, bind covalent bond, covalently to form dioxygen, a colorless and odorless diatomic gas with the chemical formula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outline Of Metrology And Measurement
The following is a topical outline of the English language Wikipedia articles on the topic of metrology and measurement. Metrology is the science of measurement and its application. Main articles * Metrology * Measurement Metrology overviews * Dimensional metrology * Forensic metrology * Historical metrology * Smart Metrology * Time metrology * Quantum metrology History * History of measurement * History of the metre Concepts * Quantification (science) * Standard (metrology) * Weights and measures * Unit of measurement Geodesy * Geodesy - the science of measuring and representing the geometry, gravity, and spatial orientation of the Earth in temporally varying 3D. * List of geodesists * History of geodesy * Physical geodesy * International Union of Geodesy and Geophysics * International Association of Geodesy Systems and units * Unit of measurement * System of measurement Systems of measurement * System of measurement * Metric system * Unit prefixes * Metric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
