“contact”的概念、定义、翻译、参考文献-科学参考

contact

Mathematics

Two real functions f(x) and g(x) (or the graphs they define) have contact of order k at the value x = a if

$f^{(i)} (a) = g^{(i)} (a) for 0 \leq i \leq k and f^{(k + 1)} (a) \neq g^{(k + 1)} (a) .$

The graphs intersect if the order of contact is at least 0, touch if the order of contact is at least 1, and the order of contact is at least two if the graphs touch and have equal curvature.

Electronics and Electrical Engineering

The bringing together of two conductors so that current may flow. The resistance at the interface between the conductors is the contact resistance. In the case of an ohmic contact between a metal and a semiconductor, the specific contact resistance is the contact resistance of a unit area for current flow perpendicular to the contact. In the case of a planar configuration where the final direction of current flow is parallel to the plane of the metal (see diagram), the contact resistance is defined to be the resistance between the metal and an imaginary plane at the edge of and perpendicular to the metal, and the transfer length, L, is the distance from the edge of the metal at which the current in the semiconductor has fallen to 1/e of its original value.
Contact resistance and transfer length
If the conductors are made from two different materials a difference of potential will arise when they are placed in contact. This contact potential results from a difference in the work functions of the two materials and is usually of the order of a few tenths of a volt. If the contact is made between two semiconductors of different polarities or between a metal and a semiconductor, a built-in field will be produced with an associated contact resistance to current flow. See also p-n junction; metal-semiconductor contact.

Geology and Earth Sciences

The depositional, intrusive, or faulted surface along which two different rock types are juxtaposed. The term is especially applicable to situations where plutonic igneous rocks intrude into country rocks; in this context ‘contact’ also refers to the effect on country rocks of conductive or convective heat transfer (i.e. contact metamorphism).

单词	contact
释义	contact Mathematics Two real functions f(x) and g(x) (or the graphs they define) have contact of order k at the value x = a if $f^{(i)} (a) = g^{(i)} (a) for 0 \leq i \leq k and f^{(k + 1)} (a) \neq g^{(k + 1)} (a) .$ The graphs intersect if the order of contact is at least 0, touch if the order of contact is at least 1, and the order of contact is at least two if the graphs touch and have equal curvature. Electronics and Electrical Engineering The bringing together of two conductors so that current may flow. The resistance at the interface between the conductors is the contact resistance. In the case of an ohmic contact between a metal and a semiconductor, the specific contact resistance is the contact resistance of a unit area for current flow perpendicular to the contact. In the case of a planar configuration where the final direction of current flow is parallel to the plane of the metal (see diagram), the contact resistance is defined to be the resistance between the metal and an imaginary plane at the edge of and perpendicular to the metal, and the transfer length, L, is the distance from the edge of the metal at which the current in the semiconductor has fallen to 1/e of its original value. Contact resistance and transfer length If the conductors are made from two different materials a difference of potential will arise when they are placed in contact. This contact potential results from a difference in the work functions of the two materials and is usually of the order of a few tenths of a volt. If the contact is made between two semiconductors of different polarities or between a metal and a semiconductor, a built-in field will be produced with an associated contact resistance to current flow. See also p-n junction; metal-semiconductor contact. Geology and Earth Sciences The depositional, intrusive, or faulted surface along which two different rock types are juxtaposed. The term is especially applicable to situations where plutonic igneous rocks intrude into country rocks; in this context ‘contact’ also refers to the effect on country rocks of conductive or convective heat transfer (i.e. contact metamorphism).
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