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Longitudinal Focusing
Longitudinal is a geometric term of location which may refer to: * Longitude ** Line of longitude, also called a meridian * Longitudinal engine, an internal combustion engine in which the crankshaft is oriented along the long axis of the vehicle, front to back * Longitudinal mode, a particular standing wave pattern of a resonant cavity formed by waves confined in the cavity * Longitudinal redundancy check, in telecommunication, a form of redundancy check that is applied independently to each of a parallel group of bit streams. * Longitudinal study, a research study that involves repeated observations of the same items over long periods of time — often many decades * Longitudinal voltage, in telecommunication, a voltage induced or appearing along the length of a transmission medium * Longitudinal wave, a wave with oscillations or vibrations along or parallel to their direction of travel * Longitudinal/longitudinally are also anatomical terms of location. See also * Latitudinal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geometric Term Of Location
{{unreferenced, date=March 2014 Geometric terms of location describe directions or positions relative to the shape of an object. These terms are used in descriptions of engineering, physics, and other sciences, as well as ordinary day to day discourse. Though these terms by themselves may be somewhat ambiguous, they are usually used in a context in which their meaning is clear. For example, when referring to a drive shaft it is clear what is meant by axial or radial directions. Or, in a free body diagram, one may similarly infer a sense of orientation by the forces or other vectors represented. Examples Common geometric terms of location are: * Axial – along the center of a round body, or the axis of rotation of a body * Radial – along a direction pointing along a radius from the center of an object, or perpendicular to a curved path. * Circumferential (or azimuthal) – following around a curve or circumference of an object. For instance: the pattern of cells in Taylor–C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longitude
Longitude (, ) is a geographic coordinate that specifies the east– west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek letter lambda (λ). Meridians are semicircular lines running from pole to pole that connect points with the same longitude. The prime meridian defines 0° longitude; by convention the International Reference Meridian for the Earth passes near the Royal Observatory in Greenwich, England on the island of Great Britain. Positive longitudes are east of the prime meridian, and negative ones are west. Because of the Earth's rotation, there is a close connection between longitude and time measurement. Scientifically precise local time varies with longitude: a difference of 15° longitude corresponds to a one-hour difference in local time, due to the differing position in relation to the Sun. Comparing local time to an absolute measure of time a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meridian (geography)
In geography and geodesy, a meridian is the locus connecting points of equal longitude, which is the angle (in degrees or other units) east or west of a given prime meridian (currently, the IERS Reference Meridian). In other words, it is a line of longitude. The position of a point along the meridian is given by that longitude and its latitude, measured in angular degrees north or south of the Equator. On a Mercator projection or on a Gall-Peters projection, each meridian is perpendicular to all circles of latitude. A meridian is half of a great circle on Earth's surface. The length of a meridian on a modern ellipsoid model of Earth ( WGS 84) has been estimated as . Pre-Greenwich The first prime meridian was set by Eratosthenes in 200 BCE. This prime meridian was used to provide measurement of the earth, but had many problems because of the lack of latitude measurement. Many years later around the 19th century there were still concerns of the prime meridian. Mu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longitudinal Engine
In automotive engineering, a longitudinal engine is an internal combustion engine in which the crankshaft is oriented along the long axis of the vehicle, front to back. Use This type of motor is usually used for rear-wheel drive cars, except for some Audi and SAAB models equipped with longitudinal engines in front wheel drive. In front-wheel drive cars a transverse engine is usually used. Trucks often have longitudinal engines with rear-wheel drive. For motorcycles, the use of a particular type depends on the drive: in case of a chain or belt drive a transverse engine is usually used, and with shaft drives a longitudinal engine. Longitudinal engines in motorcycles do have one disadvantage: the "tipping point" of the crankshaft tilts along the entire motorcycle to a greater or lesser degree when accelerating. This is partly resolved by having other components, such as the generator and the gearbox, rotate in the opposite direction to the crankshaft. Most larger, "premium" veh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longitudinal Mode
A longitudinal mode of a resonant cavity is a particular standing wave pattern formed by waves confined in the cavity. The longitudinal modes correspond to the wavelengths of the wave which are reinforced by constructive interference after many reflections from the cavity's reflecting surfaces. All other wavelengths are suppressed by destructive interference. A longitudinal mode pattern has its nodes located axially along the length of the cavity. Transverse modes, with nodes located perpendicular to the axis of the cavity, may also exist. Simple cavity A common example of longitudinal modes are the light wavelengths produced by a laser. In the simplest case, the laser's optical cavity is formed by two opposed plane (flat) mirrors surrounding the gain medium (a plane-parallel or Fabry–Pérot cavity). The allowed modes of the cavity are those where the mirror separation distance ''L'' is equal to an exact multiple of half the wavelength, ''λ'': : L = q \frac where ''q'' i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longitudinal Redundancy Check
In telecommunication, a longitudinal redundancy check (LRC), or horizontal redundancy check, is a form of redundancy check that is applied independently to each of a parallel group of bit streams. The data must be divided into transmission blocks, to which the additional check data is added. The term usually applies to a single parity bit per bit stream, calculated independently of all the other bit streams ( BIP-8), : "Reliable link layer protocols". although it could also be used to refer to a larger Hamming code. This "extra" LRC word at the end of a block of data is very similar to checksum and cyclic redundancy check (CRC). Optimal rectangular code While simple longitudinal parity can only detect errors, it can be combined with additional error-control coding, such as a transverse redundancy check (TRC), to correct errors. The transverse redundancy check is stored on a dedicated "parity track". Whenever any single-bit error occurs in a transmission block of dat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longitudinal Study
A longitudinal study (or longitudinal survey, or panel study) is a research design that involves repeated observations of the same variables (e.g., people) over short or long periods of time (i.e., uses longitudinal data). It is often a type of observational study, although it can also be structured as longitudinal randomized experiment. Longitudinal studies are often used in social-personality and clinical psychology, to study rapid fluctuations in behaviors, thoughts, and emotions from moment to moment or day to day; in developmental psychology, to study developmental trends across the life span; and in sociology, to study life events throughout lifetimes or generations; and in consumer research and political polling to study consumer trends. The reason for this is that, unlike cross-sectional studies, in which different individuals with the same characteristics are compared, longitudinal studies track the same people, and so the differences observed in those people are less l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longitudinal Voltage
Common-mode signal is the voltage common to both input terminals of an electrical device. In telecommunication, the common-mode signal on a transmission line is also known as longitudinal voltage. In most electrical circuits the signal is transferred by a differential voltage between two conductors. If the voltages on these conductors are U1 and U2, the common-mode signal is the half-sum of the voltages: :U_\text = \frac When referenced to the local common or ground, a common-mode signal appears on both lines of a two-wire cable, in phase and with equal amplitudes. Technically, a common-mode voltage is one-half the vector sum of the voltages from each conductor of a balanced circuit to local ground or common. Such signals can arise from one or more of the following sources: * Radiated signals coupled equally to both lines, * An offset from signal common created in the driver circuit, or * A ground differential between the transmitting and receiving locations. Noise induced into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longitudinal Wave
Longitudinal waves are waves in which the vibration of the medium is parallel ("along") to the direction the wave travels and displacement of the medium is in the same (or opposite) direction of the wave propagation. Mechanical longitudinal waves are also called ''compressional'' or compression waves, because they produce compression and rarefaction when traveling through a medium, and pressure waves, because they produce increases and decreases in pressure. A wave along the length of a stretched Slinky toy, where the distance between coils increases and decreases, is a good visualization. Real-world examples include sound waves (vibrations in pressure, a particle of displacement, and particle velocity propagated in an elastic medium) and seismic P-waves (created by earthquakes and explosions). The other main type of wave is the transverse wave, in which the displacements of the medium are at right angles to the direction of propagation. Transverse waves, for instance, describe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anatomical Terms Of Location
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and anatomical axes. The meaning of terms that are used can change depending on whether an organism is bipedal or quadrupedal. Additionally, for some animals such as invertebrates, some terms may not have any meaning at all; for example, an animal that is radially symmetrical will have no anterior surface, but can still have a description that a part is close to the middle ("proximal") or further from the middle ("distal"). International organisations have determined vocabularies that are often used as standard vocabularies for subdisciplines of ana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latitudinal
In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north pole, with 0° at the Equator. Lines of constant latitude, or ''parallels'', run east–west as circles parallel to the equator. Latitude and ''longitude'' are used together as a coordinate pair to specify a location on the surface of the Earth. On its own, the term "latitude" normally refers to the ''geodetic latitude'' as defined below. Briefly, the geodetic latitude of a point is the angle formed between the vector perpendicular (or ''normal'') to the ellipsoidal surface from the point, and the plane of the equator. Background Two levels of abstraction are employed in the definitions of latitude and longitude. In the first step the physical surface is modeled by the geoid, a surface which approximates the mean sea level over the ocean ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longitudinal Axis (other) passing through the centroid of the cross sections along the long axis of an object
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Longitudinal axis may refer to: *In anatomy, going from head to tail; see *In aviation, nose to tail of a plane; see * In geography, an imaginary line In general, an imaginary line is usually any sort of geometric line that has only an abstract definition and does not physically exist. In fact, they are used to properly identify places on a map. Some outside geography do exist, such as th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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