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Gram (pen Cap On Scale)
The gram (originally gramme; SI unit symbol g) is a unit of mass in the International System of Units (SI) equal to one one thousandth of a kilogram. Originally defined as of 1795 as "the absolute weight of a volume of pure water equal to the cube of the hundredth part of a metre the_temperature_of_Melting_point.html" "title="Melting_point_of_water.html" ;"title="Cubic_centimetre.html" ;"title=" Cubic centimetre">cm3], and at Melting point of water">the temperature of Melting point">melting ice", the defining temperature (~0 °C) was later changed to 4 °C, the temperature of maximum density of water. However, by the late 19th century, there was an effort to make the Base unit (measurement), base unit the kilogram and the gram a derived unit. In 1960, the new International System of Units defined a ''gram'' as one one-thousandth of a kilogram (i.e., one gram is Scientific notation, 1×10−3 kg). The kilogram, as of 2019, is defined by the Interna ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gram (pen Cap On Scale)
The gram (originally gramme; SI unit symbol g) is a unit of mass in the International System of Units (SI) equal to one one thousandth of a kilogram. Originally defined as of 1795 as "the absolute weight of a volume of pure water equal to the cube of the hundredth part of a metre the_temperature_of_Melting_point.html" "title="Melting_point_of_water.html" ;"title="Cubic_centimetre.html" ;"title=" Cubic centimetre">cm3], and at Melting point of water">the temperature of Melting point">melting ice", the defining temperature (~0 °C) was later changed to 4 °C, the temperature of maximum density of water. However, by the late 19th century, there was an effort to make the Base unit (measurement), base unit the kilogram and the gram a derived unit. In 1960, the new International System of Units defined a ''gram'' as one one-thousandth of a kilogram (i.e., one gram is Scientific notation, 1×10−3 kg). The kilogram, as of 2019, is defined by the Interna ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metre
The metre ( British spelling) or meter ( American spelling; see spelling differences) (from the French unit , from the Greek noun , "measure"), symbol m, is the primary unit of length in the International System of Units (SI), though its prefixed forms are also used relatively frequently. The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole along a great circle, so the Earth's circumference is approximately km. In 1799, the metre was redefined in terms of a prototype metre bar (the actual bar used was changed in 1889). In 1960, the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. The current definition was adopted in 1983 and modified slightly in 2002 to clarify that the metre is a measure of proper length. From 1983 until 2019, the metre was formally defined as the length of the path travelled by light in a vacuum in of a second. After the 2019 redefini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giga-
Giga ( or ) is a unit prefix in the metric system denoting a factor of a short-scale billion or long-scale milliard (109 or ). It has the symbol G. ''Giga'' is derived from the Greek word (''gígas''), meaning "giant". The ''Oxford English Dictionary'' reports the earliest written use of ''giga'' in this sense to be in the Reports of the IUPAC 14th Conférence Internationale de Chimie in 1947: "The following prefixes to abbreviations for the names of units should be used: G giga 109×." When referring to information units in computing, such as gigabyte, giga may sometimes mean (230); this causes ambiguity. Standards organizations discourage this and use giga- to refer to 109 in this context too. ''Gigabit'' is only rarely used with the binary interpretation of the prefix. The binary prefix '' gibi'' has been adopted for 230, while reserving ''giga'' exclusively for the metric definition. Pronunciation In English, the prefix ''giga'' can be pronounced (a hard ''g'' as in ''gi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Online Computer Library Center
OCLC, Inc., doing business as OCLC, See also: is an American nonprofit cooperative organization "that provides shared technology services, original research, and community programs for its membership and the library community at large". It was founded in 1967 as the Ohio College Library Center, then became the Online Computer Library Center as it expanded. In 2017, the name was formally changed to OCLC, Inc. OCLC and thousands of its member libraries cooperatively produce and maintain WorldCat, the largest online public access catalog (OPAC) in the world. OCLC is funded mainly by the fees that libraries pay (around $217.8 million annually in total ) for the many different services it offers. OCLC also maintains the Dewey Decimal Classification system. History OCLC began in 1967, as the Ohio College Library Center, through a collaboration of university presidents, vice presidents, and library directors who wanted to create a cooperative, computerized network for libr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Standard Serial Number
An International Standard Serial Number (ISSN) is an eight-digit serial number used to uniquely identify a serial publication, such as a magazine. The ISSN is especially helpful in distinguishing between serials with the same title. ISSNs are used in ordering, cataloging, interlibrary loans, and other practices in connection with serial literature. The ISSN system was first drafted as an International Organization for Standardization (ISO) international standard in 1971 and published as ISO 3297 in 1975. ISO subcommittee TC 46/SC 9 is responsible for maintaining the standard. When a serial with the same content is published in more than one media type, a different ISSN is assigned to each media type. For example, many serials are published both in print and electronic media. The ISSN system refers to these types as print ISSN (p-ISSN) and electronic ISSN (e-ISSN). Consequently, as defined in ISO 3297:2007, every serial in the ISSN system is also assigned a linking ISSN ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grain (unit)
A grain is a unit of measurement of mass, and in the troy weight, avoirdupois, and apothecaries' systems, equal to exactly milligrams. It is nominally based upon the mass of a single ideal seed of a cereal. From the Bronze Age into the Renaissance, the average masses of wheat and barley grains were part of the legal definitions of units of mass. Expressions such as "thirty-two grains of wheat, taken from the middle of the ear" appear to have been ritualistic formulas, essentially the premodern equivalent of legal boilerplate. Another source states that it was defined such that 252.458 units would balance of distilled water at an ambient air-water pressure and temperature of and respectively. Another book states that Captain Henry Kater, of the British Standards Commission, arrived at this value experimentally. The grain was the legal foundation of traditional English weight systems, and is the only unit that is equal throughout the troy, avoirdupois, and apothecaries' syste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metre Convention
The Metre Convention (french: link=no, Convention du Mètre), also known as the Treaty of the Metre, is an international treaty that was signed in Paris on 20 May 1875 by representatives of 17 nations (Argentina, Austria-Hungary, Belgium, Brazil, Denmark, France, Germany, Italy, Peru, Portugal, Russia, Spain, Sweden and Norway, Switzerland, Ottoman Empire, United States of America, and Venezuela). The treaty created the International Bureau of Weights and Measures (BIPM), an intergovernmental organization under the authority of the General Conference on Weights and Measures (CGPM) and the supervision of the International Committee for Weights and Measures (CIPM), that coordinates international metrology and the development of the metric system. As well as founding the BIPM and laying down the way in which the activities of the BIPM should be financed and managed, the Metre Convention established a permanent organizational structure for member governments to act in common ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planck Constant
The Planck constant, or Planck's constant, is a fundamental physical constant of foundational importance in quantum mechanics. The constant gives the relationship between the energy of a photon and its frequency, and by the mass-energy equivalence, the relationship between mass and frequency. Specifically, a photon's energy is equal to its frequency multiplied by the Planck constant. The constant is generally denoted by h. The reduced Planck constant, or Dirac constant, equal to the constant divided by 2 \pi, is denoted by \hbar. In metrology it is used, together with other constants, to define the kilogram, the SI unit of mass. The SI units are defined in such a way that, when the Planck constant is expressed in SI units, it has the exact value The constant was first postulated by Max Planck in 1900 as part of a solution to the ultraviolet catastrophe. At the end of the 19th century, accurate measurements of the spectrum of black body radiation existed, but the distr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Bureau Of Weights And Measures
The International Bureau of Weights and Measures (french: Bureau international des poids et mesures, BIPM) is an intergovernmental organisation, through which its 59 member-states act together on measurement standards in four areas: chemistry, ionising radiation, physical metrology, and coordinated universal time. It is based in Saint-Cloud, Paris, France. The organisation has been referred to as IBWM (from its name in English) in older literature. Structure The BIPM is supervised by the International Committee for Weights and Measures (french: Comité international des poids et mesures, CIPM), a committee of eighteen members that meet normally in two sessions per year, which is in turn overseen by the General Conference on Weights and Measures (french: Conférence générale des poids et mesures, CGPM) that meets in Paris usually once every four years, consisting of delegates of the governments of the Member States and observers from the Associates of the CGPM. These orga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2019 Redefinition Of The SI Base Units
In 2019, four of the seven SI base units specified in the International System of Quantities were redefined in terms of natural physical constants, rather than human artifacts such as the standard kilogram. Effective 20 May 2019, the 144th anniversary of the Metre Convention, the kilogram, ampere, kelvin, and mole are now defined by setting exact numerical values, when expressed in SI units, for the Planck constant ('), the elementary electric charge ('), the Boltzmann constant (), and the Avogadro constant (), respectively. The second, metre, and candela had previously been redefined using physical constants. The four new definitions aimed to improve the SI without changing the value of any units, ensuring continuity with existing measurements. In November 2018, the 26th General Conference on Weights and Measures (CGPM) unanimously approved these changes, The conference ran from 13–16 November and the vote on the redefinition was scheduled for the last day. Kazakhsta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific Notation
Scientific notation is a way of expressing numbers that are too large or too small (usually would result in a long string of digits) to be conveniently written in decimal form. It may be referred to as scientific form or standard index form, or standard form in the United Kingdom. This base ten notation is commonly used by scientists, mathematicians, and engineers, in part because it can simplify certain arithmetic operations. On scientific calculators it is usually known as "SCI" display mode. In scientific notation, nonzero numbers are written in the form or ''m'' times ten raised to the power of ''n'', where ''n'' is an integer, and the coefficient ''m'' is a nonzero real number (usually between 1 and 10 in absolute value, and nearly always written as a terminating decimal). The integer ''n'' is called the exponent and the real number ''m'' is called the '' significand'' or ''mantissa''. The term "mantissa" can be ambiguous where logarithms are involved, because it is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Base Unit (measurement)
A base unit (also referred to as a fundamental unit) is a unit adopted for measurement of a '' base quantity''. A base quantity is one of a conventionally chosen subset of physical quantities, where no quantity in the subset can be expressed in terms of the others. The SI base units, or ''Systeme International d'unites'', consists of the metre, kilogram, second, ampere, Kelvin, mole and candela. A secondary unit for the same quantity is a '' derived unit''; for example, when used with the International System of Units, the gram is a derived unit, not a base unit. Background In the language of measurement, ''physical quantities'' are quantifiable aspects of the world, such as time, distance, velocity, mass, temperature, energy, and weight, and ''units'' are used to describe their magnitude or quantity. Many of these quantities are related to each other by various physical laws, and as a result the units of a quantities can be generally be expressed as a product of powers of other u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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