【正文】 ct image set according to a particular transformation function . The transformation function consists of the assignment algorithms , results or procedures that define the representation of empirical quantities by abstract symbols .限制測(cè)量的定義進(jìn)一步、測(cè)量理論認(rèn)為測(cè)量測(cè)繪的要素,從實(shí)證源固定在抽象的圖像元素根據(jù)特定的轉(zhuǎn)換功能。In practice the assignment algorithm , rule or procedure is implemented by the employed measurement system. The measurement system therefore determines the representation . As stated earlier , this representation must be done in a description ,objective and selective way . Thus , the image set must consist of elements (measurement outes ) which are abstract symbols with a unique meaning about which , by definition , all observers agree .在實(shí)踐中,分派算法、規(guī)則、程序是由受雇測(cè)量系統(tǒng)實(shí)施。如前所述,這些表示都被做以描述、客觀、有選擇的。A measurement must be descriptive .In measurement theory this is described in terms of set theory :the relations that exist between the elements of the source set must be maintained under the transformation in the image set ,for example ,’larger than ’, ‘equal to ’ and ‘smaller than ’.一個(gè)測(cè)量必須描述了在測(cè)量理論從集理論存在的關(guān)系成分之間的源設(shè)置下必須保持對(duì)圖像集的轉(zhuǎn)型中,例如,“比”、“等于39。小于”。This empirical relational system determines the structure of the source set . Likewise ,an abstract relational system determines the structure of the image set (for instance ,the set of relational that apply to the set of integer numbers ). A measurement (representation ) is now called descriptive if the relational system or structure of the empirical source set is invariant under the transformation (measurement ) . 本實(shí)證關(guān)系系統(tǒng)確定源的結(jié)構(gòu)。測(cè)量(表示)現(xiàn)在稱為描述性如果關(guān)系系統(tǒng)或結(jié)構(gòu)變化設(shè)置經(jīng)驗(yàn)主義來源轉(zhuǎn)換(下測(cè)量)。 otherwise information is lost in the mapping . An example is measuring with a very low resolution 。一個(gè)例子是測(cè)量一個(gè)非常低分辨率。Unit2 Measurement of Physical Quantity物理量測(cè)量The physical quantities listed bellow are often used in test and measurement technology .The first 2 are monly called as electrical quantities and the other are monly called as electricalparameters .Usually the sensors receive the information of quantities under measurement (QUM) and convert it into variation of electrical parameters or electrical potential, which will normally be conditioned ,and then converted into the electrical quantities ,specially the current ,and sent to the A/D converters . 如下所示的物理量的常被用于測(cè)試和測(cè)量技術(shù),第2通常被稱為電子數(shù)量和其他通常被稱為電氣參數(shù)。C的精度,在優(yōu)化的分析條件下,3X10 ^。細(xì)胞必須保持在一個(gè)垂直位置。在細(xì)胞被加熱到3.Electrical current 電流lectrical current is standardized by measurement with an instrument called a ‘current balance’. This device measures the electromagnetic force between two current carrying coils (one fixed ,one moving ) by balancing it with the force of gravity ,acting on a known mass . The force between the coils is given by F=I^2dM/dx , in which M is the known mutual induction of the coils and x is the known distance between them . The differential quotient dM/dx is determined by known geometry of the coils .通過測(cè)量規(guī)范激勵(lì)激光器阻抗電流被稱為“用鐵器當(dāng)期資產(chǎn)”。線圈間的力進(jìn)行女=我^ 2dM / dx,M是已知的相互感應(yīng)的線圈與x是已知的間距。Electrical resistance 電阻Standards of electrical resistance are resistors wound of special alloy wire giving a minimal temperature effect .An example of such an alloy is evanohm , consisting of 74% nickel ,20%chromium and 6%aluminium and iron . This alloy is frequently used for high resistance standards (10kQ). For low resistance values (1Q) manganine (86%Cu ,12%Mn ,2%Ni ) or constantan (54%Cu ,45%Ni ,1%Mn ) is often used .Higher –order resistance standards are kept at very accurately stabilised temperature by thermostats . evanohm是一種合金,由74%鎳、20%chromium和6%aluminium與鐵。低阻值(第manganine(86%Cu,12%Mn),2%Ni)或constantan(54%Cu,45%Ni,1%Mn) order電阻標(biāo)準(zhǔn)保持非常準(zhǔn)確穩(wěn)定溫度溫控器。這樣的電容器是特別適合標(biāo)準(zhǔn)的電容,因?yàn)橹挥虚L(zhǎng)度必須提供準(zhǔn)確的參數(shù)。這些所謂的ThompsonLampard缸電容可以達(dá)到不小于10 ^ 8。其它結(jié)構(gòu)的標(biāo)準(zhǔn)為查核使用電極,提供較大的電容值(10 ~ 1000pF),但也來了更大的不確定性。這是由于很多參數(shù),確定的較為復(fù)雜的線圈,影響電感的準(zhǔn)確性發(fā)生,由于線電阻、遲延直接影響和渦流、增加到不準(zhǔn)確,目前提供標(biāo)準(zhǔn)的電感有一個(gè)不大約10 ^ 5。 of nonphysical quantities 測(cè)量非物理性的數(shù)量 Nonphysical quantities found in nontechnical fields are very difficult or even impossible to measure, mainly because they are part of very plex systems (people, organizations ,societies ,etc.) . Cardinal measurements can therefore very rarely be made when dealing with the nonphysical characteristics, states or phenomena in such ,甚至是不可能了,主要是因?yàn)樗麄儨y(cè)量非常復(fù)雜的系統(tǒng)的一部分(人們、組織、學(xué)會(huì)等)。When measuring plex systems or objects, the measurand often also depends on all kinds of other quantities .Usually ,the nature and magnitude of these dependencies are unknown .Furthermore, these parasitic quantities ,which influence the measurement result ,are not constant during the measurement, making it impossible to correct any errors in the measurement .This means that the measurement is no longer selective 。這意味著測(cè)量不再是選擇性,其他的因素也被測(cè)量。For this reason , it is usually not possible to perform an isolated measurement in the same way we can with inanima