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Degree Fahrenheit
The Fahrenheit scale () is a temperature scale based on one proposed in 1724 by the physicist Daniel Gabriel Fahrenheit (1686–1736). It uses the degree Fahrenheit (symbol: °F) as the unit. Several accounts of how he originally defined his scale exist, but the original paper suggests the lower defining point, 0 °F, was established as the freezing temperature of a solution of brine made from a mixture of water, ice, and ammonium chloride (a salt). The other limit established was his best estimate of the average human body temperature, originally set at 90 °F, then 96 °F (about 2.6 °F less than the modern value due to a later redefinition of the scale). For much of the 20th century, the Fahrenheit scale was defined by two fixed points with a 180 °F separation: the temperature at which pure water freezes was defined as 32 °F and the boiling point of water was defined to be 212 °F, both at sea level and under standard atmospheric pressure. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Celsius
The degree Celsius is the unit of temperature on the Celsius scale (originally known as the centigrade scale outside Sweden), one of two temperature scales used in the International System of Units (SI), the other being the Kelvin scale. The degree Celsius (symbol: °C) can refer to a specific temperature on the Celsius scale or a unit to indicate a difference or range between two temperatures. It is named after the Swedish astronomer Anders Celsius (1701–1744), who developed a similar temperature scale in 1742. Before being renamed in 1948 to honour Anders Celsius, the unit was called ''centigrade'', from the Latin ''centum'', which means 100, and ''gradus'', which means steps. Most major countries use this scale; the other major scale, Fahrenheit, is still used in the United States, some island territories, and Liberia. The Kelvin scale is of use in the sciences, with representing absolute zero. Since 1743 the Celsius scale has been based on 0 °C for the freezing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Level
Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardised geodetic datumthat is used, for example, as a chart datum in cartography and marine navigation, or, in aviation, as the standard sea level at which atmospheric pressure is measured to calibrate altitude and, consequently, aircraft flight levels. A common and relatively straightforward mean sea-level standard is instead the midpoint between a mean low and mean high tide at a particular location. Sea levels can be affected by many factors and are known to have varied greatly over geological time scales. Current sea level rise is mainly caused by human-induced climate change. When temperatures rise, Glacier, mountain glaciers and the Ice sheet, polar ice caps melt, increasing the amount of water in water bodies. Because most of human settlem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cayman Islands
The Cayman Islands () is a self-governing British Overseas Territory—the largest by population in the western Caribbean Sea. The territory comprises the three islands of Grand Cayman, Cayman Brac and Little Cayman, which are located to the south of Cuba and northeast of Honduras, between Jamaica and Mexico's Yucatán Peninsula. The capital city is George Town on Grand Cayman, which is the most populous of the three islands. The Cayman Islands is considered to be part of the geographic Western Caribbean Zone as well as the Greater Antilles. The territory is a major world offshore financial centre for international businesses and wealthy individuals, largely as a result of the state not charging taxes on any income earned or stored. With a GDP per capita of $91,392, the Cayman Islands has the highest standard of living in the Caribbean. Immigrants from over 130 countries and territories reside in the Cayman Islands. History No archaeological evidence for an indigenous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marshall Islands
The Marshall Islands ( mh, Ṃajeḷ), officially the Republic of the Marshall Islands ( mh, Aolepān Aorōkin Ṃajeḷ),'' () is an independent island country and microstate near the Equator in the Pacific Ocean, slightly west of the International Date Line. Geographically, the country is part of the larger island group of Micronesia. The country's population of 58,413 people (at the 2018 World Bank Census) is spread out over five islands and 29 coral atolls, comprising 1,156 individual islands and islets. The capital and largest city is Majuro. It has the largest portion of its territory composed of water of any sovereign state, at 97.87%. The islands share maritime boundaries with Wake Island to the north, Kiribati to the southeast, Nauru to the south, and Federated States of Micronesia to the west. About 52.3% of Marshall Islanders (27,797 at the 2011 Census) live on Majuro. In 2016, 73.3% of the population were defined as being "urban". The UN also indicates a population d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Federated States Of Micronesia
The Federated States of Micronesia (; abbreviated FSM) is an island country in Oceania. It consists of four states from west to east, Yap, Chuuk, Pohnpei and Kosraethat are spread across the western Pacific. Together, the states comprise around 607 islands (a combined land area of approximately ) that cover a longitudinal distance of almost just north of the equator. They lie northeast of Indonesia and Papua New Guinea, south of Guam and the Marianas, west of Nauru and the Marshall Islands, east of Palau and the Philippines, about north of eastern Australia, 3,400 km (2,133 mi) southeast of Japan, and some southwest of the main islands of the Hawaiian Islands. While the FSM's total land area is quite small, the country's waters occupy more than of the Pacific Ocean, giving the country the 14th-largest exclusive economic zone in the world. The sovereign island nation's capital is Palikir, located on Pohnpei Island, while the largest city is Weno, located in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palau
Palau,, officially the Republic of Palau and historically ''Belau'', ''Palaos'' or ''Pelew'', is an island country and microstate in the western Pacific. The nation has approximately 340 islands and connects the western chain of the Caroline Islands with parts of the Federated States of Micronesia. It has a total area of . The most populous island is Koror, home to the country's most populous city of the same name. The capital Ngerulmud is located on the nearby island of Babeldaob, in Melekeok State. Palau shares maritime boundaries with international waters to the north, the Federated States of Micronesia to the east, Indonesia to the south, and the Philippines to the northwest. The country was originally settled approximately 3,000 years ago by migrants from Maritime Southeast Asia. Palau was first drawn on a European map by the Czech missionary Paul Klein based on a description given by a group of Palauans shipwrecked on the Philippine coast on Samar. Palau islands ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compact Of Free Association
The Compact of Free Association (COFA) is an international agreement establishing and governing the relationships of free association between the United States and the three Pacific Island sovereign states of the Federated States of Micronesia (FSM), the Republic of the Marshall Islands (RMI), and the Republic of Palau. As a result, these countries are sometimes known as the Freely Associated States. These nations, together with the Commonwealth of the Northern Mariana Islands, formerly comprised the Trust Territory of the Pacific Islands, a United Nations trusteeship administered by the United States Navy from 1947 to 1951 and by the US Department of the Interior from 1951 to 1986 (to 1994 for Palau). The compact came into being as an extension of the US–UN territorial trusteeship agreement, which obliged the federal government of the United States "to promote the development of the people of the Trust Territory toward self-government or independence as appropriate to the part ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unincorporated Territories Of The United States
Territories of the United States are sub-national administrative divisions overseen by the federal government of the United States. The various American territories differ from the U.S. states and tribal reservations as they are not sovereign entities. In contrast, each state has a sovereignty separate from that of the federal government and each federally recognized Native American tribe possesses limited tribal sovereignty as a "dependent sovereign nation". Territories are classified by incorporation and whether they have an "organized" government through an organic act passed by the Congress. American territories are under American sovereignty and, consequently, may be treated as part of the United States ''proper'' in some ways and not others (i.e., territories belong to, but are not considered to be a part of, the United States). Unincorporated territories in particular are not considered to be integral parts of the United States, and the Constitution of the United St ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caesium
Caesium (IUPAC spelling) (or cesium in American English) is a chemical element with the symbol Cs and atomic number 55. It is a soft, silvery-golden alkali metal with a melting point of , which makes it one of only five elemental metals that are liquid at or near room temperature. Caesium has physical and chemical properties similar to those of rubidium and potassium. It is pyrophoric and reacts with water even at . It is the least electronegative element, with a value of 0.79 on the Pauling scale. It has only one stable isotope, caesium-133. Caesium is mined mostly from pollucite. The element has 40 known isotopes, making it, along with barium and mercury, one of the elements with the most isotopes. Caesium-137, a fission product, is extracted from waste produced by nuclear reactors. The German chemist Robert Bunsen and physicist Gustav Kirchhoff discovered caesium in 1860 by the newly developed method of flame spectroscopy. The first small-scale applications for caesium ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is equal to one event per second. The period is the interval of time between events, so the period is the reciprocal of the frequency. For example, if a heart beats at a frequency of 120 times a minute (2 hertz), the period, —the interval at which the beats repeat—is half a second (60 seconds divided by 120 beats). Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light. Definitions and units For cyclical phenomena such as oscillations, waves, or for examples of simple harmonic motion, the term ''frequency'' is defined as the number of cycles or vibrations per unit of time. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperfine Transition
In atomic physics, hyperfine structure is defined by small shifts in otherwise degenerate energy levels and the resulting splittings in those energy levels of atoms, molecules, and ions, due to electromagnetic multipole interaction between the nucleus and electron clouds. In atoms, hyperfine structure arises from the energy of the nuclear magnetic moment, nuclear magnetic dipole moment interacting with the magnetic field generated by the electrons and the energy of the quadrupole, nuclear electric quadrupole moment in the electric field gradient due to the distribution of charge within the atom. Molecular hyperfine structure is generally dominated by these two effects, but also includes the energy associated with the interaction between the magnetic moments associated with different magnetic nuclei in a molecule, as well as between the nuclear magnetic moments and the magnetic field generated by the rotation of the molecule. Hyperfine structure contrasts with ''fine structure'', wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ground-state
The ground state of a quantum mechanics, quantum-mechanical system is its stationary state of lowest energy; the energy of the ground state is known as the zero-point energy of the system. An excited state is any state with energy greater than the ground state. In quantum field theory, the ground state is usually called the vacuum state or the vacuum#The quantum-mechanical vacuum, vacuum. If more than one ground state exists, they are said to be degenerate energy level, degenerate. Many systems have degenerate ground states. Degeneracy occurs whenever there exists a unitary operator that acts non-trivially on a ground state and commutator, commutes with the Hamiltonian (quantum mechanics), Hamiltonian of the system. According to the third law of thermodynamics, a system at absolute zero temperature exists in its ground state; thus, its entropy is determined by the degeneracy of the ground state. Many systems, such as a perfect crystal lattice, have a unique ground state and ther ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
