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Differential Mobility Spectrometer
Differential may refer to: Mathematics * Differential (mathematics) comprises multiple related meanings of the word, both in calculus and differential geometry, such as an infinitesimal change in the value of a function * Differential algebra * Differential calculus ** Differential of a function, represents a change in the linearization of a function *** Total differential is its generalization for functions of multiple variables ** Differential (infinitesimal) (e.g. ''dx'', ''dy'', ''dt'' etc.) are interpreted as infinitesimals ** Differential topology * Pushforward (differential), Differential (pushforward) The total derivative of a map between manifolds. * Differential exponent, an exponent in the factorisation of the different ideal * Differential geometry, exterior differential, or exterior derivative, is a generalization to differential forms of the notion of differential of a function on a differentiable manifold * Cochain complex, Differential (coboundary), in homological ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential (mathematics)
In mathematics, differential refers to several related notions derived from the early days of calculus, put on a rigorous footing, such as infinitesimal differences and the derivatives of functions. The term is used in various branches of mathematics such as calculus, differential geometry, algebraic geometry and algebraic topology. Introduction The term differential is used nonrigorously in calculus to refer to an infinitesimal ("infinitely small") change in some varying quantity. For example, if ''x'' is a variable, then a change in the value of ''x'' is often denoted Δ''x'' (pronounced '' delta x''). The differential ''dx'' represents an infinitely small change in the variable ''x''. The idea of an infinitely small or infinitely slow change is, intuitively, extremely useful, and there are a number of ways to make the notion mathematically precise. Using calculus, it is possible to relate the infinitely small changes of various variables to each other mathematically ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential Steering
Differential steering is the means of steering a land vehicle by applying more drive torque to one side of the vehicle than the other. Differential steering is the primary means of steering tracked vehicles, such as tanks and bulldozers, is also used in certain wheeled vehicles commonly known as skid-steer, and even implemented in some automobiles, where it is called torque vectoring, to augment steering by changing wheel direction relative to the vehicle. Differential steering is distinct from torque steer, which is usually considered a negative side effect of drive-train design choices. History A British agricultural company, Hornsby in Grantham, developed a continuous track, which was patented in 1905. The Hornsby tractors featured a track-steer clutch arrangement. Mechanisms There are several mechanisms that have been developed to vary the torque applied to different sides of a vehicle. These include ''clutch-brake'' steering, ''braked-differential'' steering, '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential Centrifugation
In biochemistry and cell biology, differential centrifugation (also known as differential velocity centrifugation) is a common procedure used to separate organelles and other sub-cellular particles based on their sedimentation rate. Although often applied in biological analysis, differential centrifugation is a general technique also suitable for crude purification of non-living suspended particles (e.g. nanoparticles, colloidal particles, viruses). In a typical case where differential centrifugation is used to analyze cell-biological phenomena (e.g. organelle distribution), a tissue sample is first lysed to break the cell membranes and release the organelles and cytosol. The lysate is then subjected to repeated centrifugations, where particles that sediment sufficiently quickly at a given centrifugal force for a given time form a compact "pellet" at the bottom of the centrifugation tube. After each centrifugation, the ''supernatant'' (non-pelleted solution) is removed from t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential Rotation
Differential rotation is seen when different parts of a rotating object move with different angular velocities (rates of rotation) at different latitudes and/or depths of the body and/or in time. This indicates that the object is not solid. In fluid objects, such as accretion disks, this leads to shearing. Galaxies and protostars usually show differential rotation; examples in the Solar System include the Sun, Jupiter and Saturn. Around the year 1610, Galileo Galilei observed sunspots and calculated the rotation of the Sun. In 1630, Christoph Scheiner reported that the Sun had different rotational periods at the poles and at the equator, in good agreement with modern values. The cause of differential rotation Stars and planets rotate in the first place because conservation of angular momentum turns random drifting of parts of the molecular cloud that they form from into rotating motion as they coalesce. Given this average rotation of the whole body, internal differential ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential Hardening
Differential heat treatment (also called selective heat treatment or local heat treatment) is a technique used during heat treating to harden or soften certain areas of a steel object, creating a difference in hardness between these areas. There are many techniques for creating a difference in properties, but most can be defined as either ''differential hardening'' or ''differential tempering''. These were common heat treating techniques used historically in Europe and Asia, with possibly the most widely known example being from Japanese swordsmithing. Some modern varieties were developed in the twentieth century as metallurgical knowledge and technology rapidly increased. Differential hardening consists of either two methods. It can involve heating the metal evenly to a red-hot temperature and then cooling it at different rates, turning part of the object into very hard martensite while the rest cools slower and becomes softer pearlite. It may also consist of heating only a part ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
White Blood Cell Differential
A white blood cell differential is a medical laboratory test that provides information about the types and amounts of white blood cells in a person's blood. The test, which is usually ordered as part of a complete blood count (CBC), measures the amounts of the five normal white blood cell typesneutrophils, lymphocytes, monocytes, eosinophils and basophilsas well as abnormal cell types if they are present. These results are reported as percentages and absolute values, and compared against reference ranges to determine whether the values are normal, low, or high. Changes in the amounts of white blood cells can aid in the diagnosis of many health conditions, including viral, bacterial, and parasitic infections and blood disorders such as leukemia. White blood cell differentials may be performed by an automated analyzera machine designed to run laboratory tests – or manually, by examining blood smears under a microscope. The test was performed manually until white blood c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential Diagnosis
In healthcare, a differential diagnosis (abbreviated DDx) is a method of analysis of a patient's history and physical examination to arrive at the correct diagnosis. It involves distinguishing a particular disease or condition from others that present with similar clinical features. Differential diagnostic procedures are used by clinicians to diagnose the specific disease in a patient, or, at least, to consider any imminently life-threatening conditions. Often, each individual option of a possible disease is called a differential diagnosis (e.g., acute bronchitis could be a differential diagnosis in the evaluation of a cough, even if the final diagnosis is common cold). More generally, a differential diagnostic procedure is a systematic diagnostic method used to identify the presence of a disease entity where multiple alternatives are possible. This method may employ algorithms, akin to the process of elimination, or at least a process of obtaining information that shrinks th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compensating Differential
Wage differential is a term used in labour economics to analyze the relation between the wage rate and the unpleasantness, risk, or other undesirable attributes of a particular job. A compensating differential, which is also called a compensating wage differential or an equalizing difference, is defined as the additional amount of income that a given worker must be offered in order to motivate them to accept a given undesirable job, relative to other jobs that worker could perform. One can also speak of the compensating differential for an especially desirable job, or one that provides special benefits, but in this case the differential would be ''negative'': that is, a given worker would be willing to accept a ''lower'' wage for an especially desirable job, relative to other jobs. The idea of compensating differentials has been used to analyze issues such as the risk of future unemployment, the risk of injury, the risk of unsafe intercourse, the monetary value workers place on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quality Spread Differential
Quality spread differential (QSD) arises during an interest rate swap in which two parties of different levels of creditworthiness experience different levels of interest rates of debt obligations. A positive QSD means that a swap is in the interest of both parties. A QSD is the difference between the default-risk premium differential on the fixed- rate debt and the default-risk premium differential on the floating-rate debt. In general, the former is greater than the latter. Example If Company A can borrow at a fixed rate of 12% or at LIBOR The London Inter-Bank Offered Rate is an interest-rate average calculated from estimates submitted by the leading banks in London. Each bank estimates what it would be charged were it to borrow from other banks. The resulting average rate is u ...+2%, while Company B can borrow at a fixed rate of 10% or at LIBOR+1%, then there is a difference of 2% in fixed rate borrowings, but of only 1% in floating rate borrowings. A difference of 1% th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Structural Differential
The structural differential is a physical chart or three-dimensional model illustrating the abstracting processes of the human nervous system. In one form, it appears as a pegboard with tags. Created by Alfred Korzybski, and awarded a U.S. patent on May 26, 1925,US Patent 1,539,194 http://pdfpiw.uspto.gov/.piw?Docid=1539194 it is used as a training device in general semantics. The device is intended to show that human "knowledge" of, or acquaintance with, anything is partial—not total. The model The structural differential consists of three basic objects. The parabola represents a domain beyond our direct observation, the sub-microscopic, dynamic world of molecules, atoms, electrons, protons, quarks, and so on; a world known to us only inferentially from science. Korzybski described it as an 'event' in the sense of "an instantaneous cross-section of a process." Thus the 'event' or parabola represents the sub-microscopic 'stuff' that, at any given moment, constitutes an apple. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semantic Differential
The semantic differential (SD) is a measurement scale designed to measure a person's subjective perception of, and affective reactions to, the properties of concepts, objects, and events by making use of a set of bipolar scales. The SD is used to assess one's opinions, attitudes, and values regarding these concepts, objects, and events in a controlled and valid way. Respondents are asked to choose where their position lies, on a set of scales with polar adjectives (for example: "sweet - bitter", "fair - unfair", "warm - cold"). Compared to other measurement scaling techniques such as Likert scaling, the SD can be assumed to be relatively reliable, valid, and robust. The SD has been used in both a general and a more specific way. Charles E. Osgood's theory of the semantic differential exemplifies the more general attempt to measure the semantics, or meaning, of words, particularly adjectives, and their referent concepts. In fields such as marketing, psychology, sociology, and info ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electronic Amplifier
An amplifier, electronic amplifier or (informally) amp is an electronic device that can increase the magnitude of a signal (a time-varying voltage or current). It may increase the power significantly, or its main effect may be to boost the voltage or current ( power, voltage or current amplifier). It is a two-port electronic circuit that uses electric power from a power supply to increase the amplitude of a signal applied to its input terminals, producing a greater amplitude signal at its output. The ratio of output to input voltage, current, or power is termed gain (voltage, current, or power gain). An amplifier, by definition has gain greater than unity (if the gain is less than unity, the device is an attenuator). An amplifier can either be a separate piece of equipment or an electrical circuit contained within another device. Amplification is fundamental to modern electronics, and amplifiers are widely used in almost all electronic equipment. Amplifiers can be cate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
