“field”的概念、定义、翻译、参考文献-科学参考

field

Physics

A region in which a body experiences a force as the result of the presence of some other body or bodies. A field is thus a method of representing the way in which bodies are able to influence each other. For example, a body that has mass is surrounded by a region in which another body that has mass experiences a force tending to draw the two bodies together. This is the gravitational field (see Newton’s law of gravitation). The other three fundamental interactions can also be represented by means of fields of force. However in the case of the magnetic field and electric field that together create the electromagnetic interaction, the force can vary in direction according to the character of the field. For example, in the field surrounding a negatively charged body, a positively charged body will experience a force of attraction, while another negatively charged body is repelled.

The strength of any field can be described as the ratio of the force experienced by a small appropriate specimen to the relevant property of that specimen, e.g. force/mass for the gravitational field. See also quantum field theory.

Mathematics

A commutative ring with identity with the following additional property:

(x) For each non-zero a there is an element a⁻¹ such that a⁻¹a = 1.

(The axiom numbering here follows on from that used for ring and integral domain.) From the defining properties of a field, Axioms (i)–(viii) and Axiom (x), it can be shown that ab = 0 only if a = 0 or b = 0. Thus Axiom (ix) holds, and so any field is an integral domain. Familiar examples of fields are the rational numbers ℚ, the real numbers ℝ and the complex numbers ℂ, each with the usual addition and multiplication. Another example is ℤ_p, the integers with addition and multiplication modulo p, where p is prime. See also Galois field.

Computer

1. (data field) An item of data consisting of a number of characters, bytes, words, or codes that are treated together, e.g. to form a number, a name, or an address. A number of fields make a record and the fields may be fixed in length or variable. The term came into use with punched card systems and a field size was defined in terms of a number of columns.
2. Normally a way of designating a portion of a word that has a specific significance or function within that word, e.g. an address field in an instruction word or a character field within a data word.
3. In mathematics, a commutative ring containing more than one element and in which every nonzero element has an inverse with respect to the multiplication operation. Apart from their obvious relationship to arithmetic involving numbers of various kinds, fields play a very important role in discussion about the analysis of algorithms. Results in this area mention the number of operations of a particular kind, and these operations are usually related to addition and multiplication of elements of some field.

Electronics and Electrical Engineering

1. The region in which a physical agency exerts its influence. Typical examples are electric and magnetic fields resulting from the presence of charge or magnetic dipoles. These are vector fields. Such a field may be pictorially represented by a set of curves, referred to as lines of force or of flux. The field density and direction at a point represent the strength and direction of the field at that point.
2. (in computing) A set of symbols treated together as a unit of information.
3. See television.

Philosophy

A central concept of physical theory. A field is defined by the distribution of a physical quantity, such as temperature, mass density, or potential energy, at different points in space. In the particularly important example of force fields, such as gravitational, electrical, and magnetic fields, the field value at a point is the force which a test particle would experience if it were located at that point. The philosophical problem is whether a force field is to be thought of as purely potential, so the presence of a field merely describes the propensity of masses to move relative to each other, or whether it should be thought of in terms of the physically real modifications of a medium whose properties result in such powers. That is, are force fields purely potential, fully characterized by dispositional statements or conditionals, or are they categorical or actual? The former option seems to require faith in ungrounded dispositions, or regions of space that differ only in what happens if an object is placed there. The lawlike shape of these dispositions, apparent for example in the curved lines of force of the magnetic field, may then seem quite inexplicable. To atomists such as Newton it would represent a return to Aristotelian entelechies, or quasi-psychological affinities between things, which are responsible for their motions (see mover, unmoved). The latter option requires understanding how forces of attraction and repulsion can be ‘grounded’ in the properties of the medium.
The basic idea of a field is arguably present in Leibniz, who was certainly hostile to Newtonian atomism, although his equal hostility to action at a distance muddies the waters. It is usually credited to Boscovich and Kant, both of whom influenced the scientist Faraday, with whose work the physical notion became established. In his paper ‘On the Physical Character of the Lines of Magnetic Force’ (1852), Faraday suggests several criteria for assessing the physical reality of lines of force, such as whether they are affected by an intervening material medium, whether they take time to propagate, and how the motion depends on the nature of what is placed at the receiving end. As far as electromagnetic fields go, Faraday himself inclined to the view that the mathematical similarity between heat flow, currents, and electro-magnetic lines of force was evidence for the physical reality of the intervening medium.

单词	field
释义	field Physics A region in which a body experiences a force as the result of the presence of some other body or bodies. A field is thus a method of representing the way in which bodies are able to influence each other. For example, a body that has mass is surrounded by a region in which another body that has mass experiences a force tending to draw the two bodies together. This is the gravitational field (see Newton’s law of gravitation). The other three fundamental interactions can also be represented by means of fields of force. However in the case of the magnetic field and electric field that together create the electromagnetic interaction, the force can vary in direction according to the character of the field. For example, in the field surrounding a negatively charged body, a positively charged body will experience a force of attraction, while another negatively charged body is repelled. The strength of any field can be described as the ratio of the force experienced by a small appropriate specimen to the relevant property of that specimen, e.g. force/mass for the gravitational field. See also quantum field theory. Mathematics A commutative ring with identity with the following additional property: (x) For each non-zero a there is an element a⁻¹ such that a⁻¹a = 1. (The axiom numbering here follows on from that used for ring and integral domain.) From the defining properties of a field, Axioms (i)–(viii) and Axiom (x), it can be shown that ab = 0 only if a = 0 or b = 0. Thus Axiom (ix) holds, and so any field is an integral domain. Familiar examples of fields are the rational numbers ℚ, the real numbers ℝ and the complex numbers ℂ, each with the usual addition and multiplication. Another example is ℤ_p, the integers with addition and multiplication modulo p, where p is prime. See also Galois field. Computer 1. (data field) An item of data consisting of a number of characters, bytes, words, or codes that are treated together, e.g. to form a number, a name, or an address. A number of fields make a record and the fields may be fixed in length or variable. The term came into use with punched card systems and a field size was defined in terms of a number of columns. 2. Normally a way of designating a portion of a word that has a specific significance or function within that word, e.g. an address field in an instruction word or a character field within a data word. 3. In mathematics, a commutative ring containing more than one element and in which every nonzero element has an inverse with respect to the multiplication operation. Apart from their obvious relationship to arithmetic involving numbers of various kinds, fields play a very important role in discussion about the analysis of algorithms. Results in this area mention the number of operations of a particular kind, and these operations are usually related to addition and multiplication of elements of some field. Electronics and Electrical Engineering 1. The region in which a physical agency exerts its influence. Typical examples are electric and magnetic fields resulting from the presence of charge or magnetic dipoles. These are vector fields. Such a field may be pictorially represented by a set of curves, referred to as lines of force or of flux. The field density and direction at a point represent the strength and direction of the field at that point. 2. (in computing) A set of symbols treated together as a unit of information. 3. See television. Philosophy A central concept of physical theory. A field is defined by the distribution of a physical quantity, such as temperature, mass density, or potential energy, at different points in space. In the particularly important example of force fields, such as gravitational, electrical, and magnetic fields, the field value at a point is the force which a test particle would experience if it were located at that point. The philosophical problem is whether a force field is to be thought of as purely potential, so the presence of a field merely describes the propensity of masses to move relative to each other, or whether it should be thought of in terms of the physically real modifications of a medium whose properties result in such powers. That is, are force fields purely potential, fully characterized by dispositional statements or conditionals, or are they categorical or actual? The former option seems to require faith in ungrounded dispositions, or regions of space that differ only in what happens if an object is placed there. The lawlike shape of these dispositions, apparent for example in the curved lines of force of the magnetic field, may then seem quite inexplicable. To atomists such as Newton it would represent a return to Aristotelian entelechies, or quasi-psychological affinities between things, which are responsible for their motions (see mover, unmoved). The latter option requires understanding how forces of attraction and repulsion can be ‘grounded’ in the properties of the medium. The basic idea of a field is arguably present in Leibniz, who was certainly hostile to Newtonian atomism, although his equal hostility to action at a distance muddies the waters. It is usually credited to Boscovich and Kant, both of whom influenced the scientist Faraday, with whose work the physical notion became established. In his paper ‘On the Physical Character of the Lines of Magnetic Force’ (1852), Faraday suggests several criteria for assessing the physical reality of lines of force, such as whether they are affected by an intervening material medium, whether they take time to propagate, and how the motion depends on the nature of what is placed at the receiving end. As far as electromagnetic fields go, Faraday himself inclined to the view that the mathematical similarity between heat flow, currents, and electro-magnetic lines of force was evidence for the physical reality of the intervening medium.
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