Homonymy in English
Иностранные языки, филология и лингвистика
Problems of Homonymy Distinguishing homonymy from polysemy Different meanings of the same homonym in terms of distribution Difference between patterned and non-patterned homonymy Conclusion Literature Introduction There is considerable contradiction in published sources about the distinction between homonyms homographs homophones and heteronyms.
1. Notion of Homonymy
2. Different classifications of Homonyms
2.1.The Classification given by A.I. Smirnitsky
2.2. The classification given by I.V. Arnold
3. Sources of Homonyms
4.Problems of Homonymy
There is considerable contradiction in published sources about the distinction between homonyms, homographs, homophones and heteronyms. Significant variant interpretations include:
Random House Unabridged Dictionary explains in greatest detail that homonym is the technically correct term for words that are simultaneously homographs and homophones but that it is used in the sense of only homograph or only homophone in nontechnical contexts. The "pronounced the same and spelled the same" definition is also given by Chambers 21st Century Dictionary, Longman Dictionary of Contemporary English and Merriam-Webster Online Dictionary, though Merriam-Webster appears to also give homonym as a synonym for either homophone or homograph. Cambridge Dictionary of American English defines homonym as "a word that is spelt the same as another word but that does not have the same meaning" and adds "A homonym is also a homophone". Collins English Dictionary (third edition) says that a homonym is "one of a group of words pronounced or spelt the same way but having different meanings" (emphasis added).
The entry for homograph in The Encyclopaedia Britannica (14th Edition) states that homographs are "words spelt but not sounded alike", and homophones are "words alike only in sound (i.e. not alike in spelling)" (italics and comment added).
Homographs are defined in the Oxford English Dictionary as words that are spelt and pronounced the same as another but with a different meaning (which is the definition of a homonym in most other sources), thus excluding pairs such as desert (abandon) and desert (arid region), which are considered homographs by most other sources.
The Encarta dictionary defines heteronym as "each of two or more words that are spelt the same, but differ in meaning and often in pronunciation" (italics added). The "Fun with Words" website similarly says that a heteronym is "One of two (or more) words that have the same spelling, but different meaning, and sometimes different pronunciation too".
The intense development of homonymy in the English language is obviously due not to one single factor but to several interrelated causes, such as the monosyllabic character of English and its analytic structure.
The abundance of homonyms is also closely connected with such a characteristic feature of the English language as the phonetic identity of word and stem or, in other words, the predominance of free forms among the most frequent roots. It is quite obvious that if the frequency of words stands in some inverse relationship to their length, the monosyllabic words will be the most frequent. Moreover, as the most frequent words are also highly polysemantic, it is only natural that they develop meanings, which in the coarse of time may deviate very far from the central one.
Homonymy is intentionally sought to provoke positive, negative or awkward connotations. Concerning the selection of initials, homonymy with shortened words serves the purpose of manipulation. The demotivated process of a shortened word hereby leads to re-motivation. The form is homonymously identical with an already lexicalized linguistic unit, which makes it easier to pronounce or recall, thus standing out from the majority of acronyms. This homonymous unit has a secondary semantic relation to the linguistic unit.
1. Notion of Homonymy
In linguistics, a homonym is one of a group of words that share the same spelling and the same pronunciation but have different meanings, usually as a result of the two words having different origins. The state of being a homonym is called homonymy.
The word "homonym" comes from the conjunction of the prefix homo- , meaning "same", and suffix -ṓnymos, meaning "name". Thus, it refers to two or more distinct concepts sharing the "same name" or signifier. The term is potentially ambiguous because there are a number of ways that two meanings can share the "same name"; thus it may be used in different ways by different speakers. In particular, some sources only require that homonyms share the same spelling or the same pronunciation (in addition to having different meanings), though these are the definitions that most other sources give for and respectively. There is similar disagreement about the definition of some of the related terms described below. This article explains what appear to be the "standard" meanings, and variant definitions are then summarized.
Examples of homonyms are stalk (which as a noun can mean part of a plant, and, as a verb, to follow/harass a person), bear (animal) and bear(carry), left (opposite of right) and left (past tense of leave). Some sources also consider the following trio of words to be homonyms, but others designate them as "only" homophones:
to, too and two (actually, to, to, too, too and two, being "for the purpose of" as in "to make it easier", the opposite of "from", also, excessively, and "2", respectively).
Some sources state that homonym meanings must be unrelated in origin (rather than just different). Thus right (correct) and right (opposed to left) would be and not homonyms.
2. Different classifications of Homonyms
2.1. Classification given by A.I. Smirnitsky
The classification, which I have mentioned above, is certainly not precise enough and does not reflect certain important features of these words, and, most important of all, their status as parts of speech. The examples given their show those homonyms may belong to both to the same and to different categories of parts of speech. Obviously, the classification of homonyms should reflect this distinctive feather. Also, the paradigm of each word should be considered, because it has been observed that the paradigms of some homonyms coincide completely, and of others only partially.
Accordingly, Professor A.I. Smirnitsky classifieds homonyms into two large classes:
Full lexical homonyms are words, which represent the same category of parts of speech and have the same paradigm.
Match n a game, a contest
Match n a short piece of wood used for producing fire
Wren n a member of the Womens Royal Naval Service
Wren n a bird
Partial homonyms are subdivided into three subgroups:
A. Simple lexico-grammatical partial homonyms are words, which belong to the same category of parts of speech. Their paradigms have only one identical form, but it is never the same form, as will be soon from the examples:
(to) found v
found v (past indef., past part. of to find)
(to) lay v
lay v (past indef. of to lie)
(to) bound v
bound v (past indef., past part. of to bind)
B. Complex lexico-grammatical partial homonyms are words of different categories of parts of speech, which have identical form in their paradigms.
Rose v (past indef. of to rise)
Made v (past indef., past part. of to make)
Left v (past indef., past part. of to leave)
Been v (past part. of to be)
C. Partial lexical homonyms are words of the same category of parts of speech which are identical only in their corresponding forms.
to lie (lay, lain) v
to lie (lied, lied) v
to hang (hung, hung) v
to hang (hanged, hanged) v
to can (canned, canned)
(I) can (could)
2.2. The classification given by I.V. Arnold
The most widely accepted classification is that recognizing homonyms proper, homophones and homographs.
Homonyms proper are words, as I have already mentioned, identical in pronunciation and spelling, like fast and liver above. Other examples are: back n part of the bodyback adv away from the front back v go back; ball n a gathering of people for dancingball n round object used in games; bark n the noise made by dogbark v to utter sharp explosive criesbark n the skin of a treebark n
a sailing ship; base n bottombase v build or place uponbase a mean; bay n part of the sea or lake filling wide-mouth opening of landbay n recess in a house or roombay v barkbay n the European laurel.
The important point is that homonyms are distinct words: not different meanings within one word.
Homophones are words of the same sound but of different spelling and meaning:
air hair; arms alms; buy by; him hymn; knight night; not knot; or oar; piece peace; rain reign; scent cent; steel steal; storey story; write right and many others.
In the sentence The play-wright on my right thinks it right that some conventional rite should symbolize the right of every man to write as he pleases the sound complex [rait] is a noun, an adjective, an adverb and a verb, has four different spellings and six different meanings. The difference may be confined to the use of a capital letter as in bill and Bill, in the following example:
“How much is my milk bill?”
“Excuse me, Madam, but my name is John.”
On the other hand, whole sentences may be homophonic: The sons raise meat The suns rays meet. To understand these one needs a wider context. If you hear the second in the course of a lecture in optics, you will understand it without thinking of the possibility of the first.
Homographs are words different in sound and in meaning but accidentally identical in spelling: bow [bou] bow [bau]; lead [li:d] lead [led]; row [rou] row [rau]; sewer [soue] sewer [sjue]; tear [tie] tear [te]; wind [wind] wind [waind] and many more.
It has been often argued that homographs constitute a phenomenon that should be kept apart from homonymy, as the object of linguistics is sound language. This viewpoint can hardly be accepted. Because of the effects of education and culture written English is a generalized national form of expression. An average speaker does not separate the written and oral form. On the contrary he is more likely to analyze the words in terms of letters than in terms of phonemes with which he is less familiar. That is why a linguist must take into consideration both the spelling and the pronunciation of words when analyzing cases of identity of form and diversity of content.
3. Sources of Homonyms
There are a lot of different sources of homonyms in English language, so lets talk about some of them, which are the most important ones, due to my point of view.
One source of homonyms is phonetic changes, which words undergo in the coarse of their historical development. As a result of such changes, two or more words, which were formally pronounced differently, may develop identical sound forms and thus become homonyms.
Night and knight, for instance, were not homonyms in Old English as the initial k in the second word was pronounced, and not dropped as it is in its modern sound form: O.E. kniht (cf. O.E. niht). A more complicated change of form brought together another pair of homonyms: to knead (O.E. cneadan) and to need (O.E. neodian).
In Old English the verb to write had the form writan, and the adjective right had the forms reht, riht. The noun sea descends from the Old English form sae, and the verb to see from O.E. seon. The noun work and the verb to work also had different forms in Old English: wyrkean and weork respectively.
Borrowing is another source of homonyms. A borrowed word may, in the final stage of its phonetic adaptation, duplicate in form either a native word or another borrowing. So, in the group of homonyms rite, n to write, v right, adj the second and the third words are of native origin whereas rite is a Latin borrowing (<Lat. ritus). In the pair piece, n peace, n, the first originates from Old French pais, and the second from O.F. (<Gaulish) pettia. Bank, n a shoreis a native word, and bank, n a financial institutionis an Italian borrowing. Fair, adj ( as in a fair deal, its not fair) is native, and fair, n a gathering of buyers and sellersis a French borrowing. Match, n a game; a contest of skill, strengthis native, and match, n a slender short piece of wood used for producing fireis a French borrowing.
Word building also contributes significantly to the growth of homonymy, and the most important type in this respect is undoubtedly conversion. Such pairs of words as comb, n to comb, v; pale, adj to pale, v; to make, v make, n are numerous in the vocabulary. Homonyms of this type, which are the same in sound and spelling but refer to different categories of parts of speech, are called lexico-grammatical homonyms.
Shortening is a further type of word building, which increases the number of homonyms. Fan, n in the sense of enthusiastic admirer of some kind of sport or of an actor, singer, etc.is a shortening produced from fanatic. Its homonym is a Latin borrowing fan, n which denotes an implement for waving lightly to produce a cool current of air. The noun rep, n denoting a kind of fabric (cf. with the Rus. penc) has three homonyms made by shortening: rep, n (< repertory), rep, n (< representative), rep, n (< reputation); all the three are informal words.
During World War II girls serving in the Womens Royal Naval Service (an auxiliary of the British Royal Navy) were jokingly nicknamed Wrens (informal). This neologistic formation made by shortening has the homonym wren, n a small bird with dark brown plumage barred with black(Rus. крапивник).
Words made by sound-imitation can also form pairs of homonyms with other words: bang, n a loud, sudden, explosive noisebang, n a fringe of hair combed over the forehead. Also: mew, n the sound the cat makesmew, n a sea gullmew, n a pen in which poultry is fattenedmews small terraced houses in Central London.
The above-described sources of homonyms have one important feature common. In all the mentioned cases the homonyms developed from two or more different words, and their similarity is purely accidental. (In this respect, conversion certainly presents an exception for in pairs of homonyms formed by conversion one word of the pair is produced from the other: a find < to find.)
Now we come to a further source of homonyms, which differs essentially from all the above cases. Two or more homonyms can originate from different meanings of the same word when, for some reason, the semantic structure of the word breaks into several parts. This type of formation of homonyms is called disintegration or split of polysemy.
From what has been said above about polysemantic words, it should become clear that the semantic structure of a polysemantic word presents a system within which all its constituent meanings are held together by logical associations. In most cases, the function of the arrangement and the unity if determined by one of the meanings.
4. Problems of Homonymy.
The synchronic treatment of English homonyms brings to the forefront a set of problems of paramount importance for different branches of applied linguistics: lexicography, foreign language teaching and information retrieval. These problems are: the criteria distinguishing homonymy from polysemy, the formulation of rules for recognizing different meanings of the same homonym in terms of distribution, and the description of difference between patterned and non-patterned homonymy. It is necessary to emphasize that all these problems are connected with difficulties created by homonymy in understanding the message by the reader or listener, not with formulating ones thoughts; they exist for the speaker though in so far as he must construct his speech in a way that would prevent all possible misunderstanding.
All three problems are so closely interwoven that it is difficult to separate them. So we shall discuss them as they appear for various practical purposes. For a lexicographer it is a problem of establishing word boundaries. It is easy enough to see that match, as in safety matches, is a separate word from the verb match to suit. But he must know whether one is justified in taking into one entry match, as in football match, and match in meet ones match ones equal.
On the synchronic level, when the difference in etymology is irrelevant, the problem of establishing the criterion for the distinction between different words identical in sound form, and different meanings of the same word becomes hard to solve. Nevertheless the problem cannot be dropped altogether as upon an efficient arrangement of dictionary entries depends the amount of time spent by readers in looking up a word: a lexicographer will either save or waste his readerstime and effort.
Actual solutions differ. It is a wildly spread practice in English lexicography to combine in one entry words of identical phonetic form showing similarity of lexical meaning or, in other words, revealing a lexical invariant, even if they belong to different parts of speech. In our country a different trend has settled. The Anglo-Russian dictionary edited by V.D. Arakin makes nine separate entries with the word right against four items given in the dictionary edited by A.S. Hornby.
The truth is that there exists no universal criterion for distinction between polysemy and homonymy.
Polysemy characterizes words that have more than one meaning -- any dictionary search will reveal that most words are polysemes -- word itself has 12 significant senses, according to Word Net1. This means that the word, word, is used in texts scanned by lexicographers to represent twelve different concepts.
The point is that words are not meanings, although they can have many meanings.
Lexicographers make a clear distinction between different words by writing separate entries for each of them, whether or not they are spelled the same way. The dictionary of Fred W. Riggs has 5 entries for the form, bow -- this shows that lexicographers recognize this form (spelling) as a way of representing five different words. Three of them are pronounced bo and two bau, which identifies two homophones in this set of five homographs, each of which is a polyseme, capable of representing more than one concept. To summarize: bow is a word-form that stands for two different homophones and, as a homograph, represents five different words.
Moreover, the form bow is polysemic and can represent more than 20 concepts (its various meanings or senses). By gratuitously putting meaning in its definition of a homograph, Word Net can mislead readers who might think that a word is a homonym because it has several meanings -- but having one word represent more than one concept is normal -- just consider term as an example: it can not only refer to the designator of a concept, but also the duration of something, like the school year or a politician's hold on office, a legal stipulation, one's standing in a relationship (on good terms) and many other notions -- more than 17 are identified in the dictionary edited be Fred W. Riggs. By contrast, homonyms are different words and each of them (as a polyseme) can have multiple meanings.
To make their definitions precise, lexicographers need criteria to distinguish different words from each other even though they are spelled the same way. This usually hinges on etymology and, sometimes, parts of speech. One might, for example, think that that firm steadfastand firm business unit are two senses of one word (polyseme). Not so! Lexicographers class them as different words because the first evolved from a Latin stem meaning throne or chair, and the latter from a different root in Italian meaning signature.
Dictionaries are not uniform in their treatment of the different grammatical forms of a word. In some of them, the adjective firm (securely) is handled as a different word from the noun firm (to settle) even though they have the same etymology. Fred W. Riggs isnt persuaded such differences justify treating grammatical classes (adjectives, nouns, and verbs) of a word-form that belongs to a single lexeme as different words -- the precise meaning of lexeme is.
explained below. The relevant point here is that deciding whether or not a form identifies one or more than one lexeme does not hinge on meanings. There is agreement that a word-form represents different words when they evolved from separate roots, and some lexicographers treat each grammatical use of a lexeme (noun, verb, adjective) as though it were a different word.
The etymological criterion may lead to distortion of the present day situation. The English vocabulary of today is not a replica of the Old English vocabulary with some additions from borrowing. It is in many respects a different system, and this system will not be revealed if the lexicographers guided by etymological criteria only.
A more or less simple, if not very rigorous, procedure based on purely synchronic data may be prompted by analysis of dictionary definitions. It may be called explanatory transformation. It is based on the assumption that if different senses rendered by the same phonetic complex can be defined with the help of an identical kernel word-group, they may be considered sufficiently near to be regarded as variants of the same word; if not, they are homonyms.
Consider the following set of examples:
The first variant (voice1) may be defined as sound uttered in speaking or singing as characteristic of a particular person, voice2 as mode of uttering sounds in speaking or singing, voice3 as the vibration of the vocal chords in sounds uttered. So far all the definitions contain one and the same kernel element rendering the invariant common basis of their meaning. It is, however, impossible to use the same kernel element for the meaning present in the fourth example. The corresponding definition is: “Voice that form of the verb that expresses the relation of the subject to the action”. This failure to satisfy the same explanation formula sets the fourth meaning apart. It may then be considered a homonym to the polysemantic word embracing the first three variants. The procedure described may remain helpful when the items considered belong to different parts of speech; the verb voice may mean, for example, to utter a sound by the aid of the vocal chords. Maugham W.S. “The Kite”
This brings us to the problem of patterned homonymy, i.e. of the invariant lexical meaning present in homonyms that have developed from one common source and belong to various parts of speech.
Is a lexicographer justified in placing the verb voice with the above meaning into the same entry with the first three variants of the noun? The same question arises with respect to after or before preposition, conjunction and adverb.
English lexicographers think it quite possible for one and the same word to function as different parts of speech. Such pairs as act n act v; back n - back v; drive n drive v; the above mentioned after and before and the like, are all treated as one word functioning as different parts of speech. This point of view was severely criticized. It was argued that one and the same word could not belong to different parts of speech simultaneously, because this would contradict the definition of the word as a system of forms.
This viewpoint is not faultless either; if one follows it consistently, one should regard as separate words all cases when words are countable nouns in one meaning and uncountable in another, when verbs can be used transitively and intransitively, etc. In this case hair1 all the hair that grows on a persons head will be one word, an uncountable noun; whereas a single thread of hairwill be denoted by another word (hair2) which, being countable, and thus different in paradigm, cannot be considered the same word. It would be tedious to enumerate all the absurdities that will result from choosing this path. A dictionary arranged on these lines would require very much space in printing and could occasion much wasted time in use. The conclusion therefore is that efficiency in lexicographic work is secured by a rigorous application of etymological criteria combined with formalized procedures of establishing a lexical invariant suggested by synchronic linguistic methods.
As to those concerned with teaching of English as a foreign language, they are also keenly interested in patterned homonymy. The most frequently used words constitute the greatest amount of difficulty, as may be summed up by the following jocular example: I think that this “that” is a conjunction but that that “that” that that man used as pronoun.
A correct understanding of this peculiarity of contemporary English should be instilled in the pupils from the very beginning, and they should be taught to find their way in sentences where several words have their homonyms in other parts of speech, as in Jespersens example: Will change of air cure love? To show the scope of the problem for the elementary stage a list of homonyms that should be classified as patterned is given below:
Above, prp, adv, a; act, n, v; after, prp, adv, cj; age, n, v; back, n, adv, v; ball, n, v; bank, n, v; before, prp, adv, cj; besides, prp, adv; bill, n, v; bloom, n, v; box, n, v. The other examples are: by, can, close, country, course, cross, direct, draw, drive, even, faint, flat, fly, for, game, general, hard, hide, hold, home, just, kind, last, leave, left, lie, light, like, little, lot, major, march, may, mean, might, mind, miss, part, plain, plane, plate, right, round, sharp, sound, spare, spell, spring, square, stage, stamp, try, type, volume, watch, well, will.
For the most part all these words are cases of patterned lexico-grammatical homonymy taken from the minimum vocabulary of the elementary stage: the above homonyms mostly differ within each group grammatically but possess some lexical invariant. That is to say, act v follows the standard four-part system of forms with a base form act, an s-form (act-s), a Past Indefinite Tense form (acted) and an ing-form (acting) and takes up all syntactic functions of verbs, whereas act n can have two forms, act (sing.) and act (pl.). Semantically both contain the most generalized component rendering the notion of doing something.
Recent investigations have shown that it is quite possible to establish and to formalize the differences in environment, either syntactical or lexical, serving to signal which of the several inherent values is to be ascribed to the variable in a given context. An example of distributional analysis will help to make this point clear.
The distribution of a lexico-semantic variant of a word may be represented as a list of structural patterns in which it occurs and the data on its combining power. Some of the most typical structural patterns for a verb are: N + V + N; N + V + Prp + N; N + V + A; N + V + adv; N + V + to + V and some others. Patterns for nouns are far less studied, but for the present case one very typical example will suffice. This is the structure: article + A + N.
In the following extract from “A Taste of Honey” by Shelagh Delaney the morpheme laugh occurs three times: I cant stand people who laugh at other people. Theyd get a bigger laugh, if they laughed at themselves.
We recognize laugh used first and last here as a verb, because the formula is N + laugh + prp + N and so the pattern is in both cases N + V + prp + N. In the beginning of the second sentence laugh is a noun and the pattern is article + A + N.
This elementary example can give a very general idea of the procedure which can be used for solving more complicated problems.
We may sum up our discussion by pointing out that whereas distinction between polysemy homonymy is relevant and important for lexicography it is not relevant for the practice of either human or machine translation. The reason for this is that different variants of a polysemantic word are not less conditioned by context then lexical homonyms. In both cases the identification of the necessary meaning is based on the corresponding distribution that can signal it and must be present in the memory either of the pupil or the machine. The distinction between patterned and non-patterned homonymy, greatly underrated until now, is of far greater importance. In non-patterned homonymy every unit is to be learned separately both from the lexical and grammatical points of view. In patterned homonymy when one knows the lexical meaning of a given word in one part of speech, one can accurately predict the meaning when the same sound complex occurs in some other part of speech, provided, of coarse, that there is sufficient context to guide one.
An important issue that needs to be discussed is the generalizability of the results from written to spoken language. Although we cannot offer definitive arguments on this point, we can cite some reasons why the results might underestimate the difference between same and different class homonyms in speech. First, the disambiguating information provided by orthography would be absent. Second, homonyms from different grammatical classes would tend to have acoustic differences that could aid in disambiguation. In particular, because of the basic clause structure of English, nouns are more likely than verbs to appear at the ends of phrases and clauses and so should tend to be longer because of durational lengthening concomitant with those boundaries. Indeed, Sorenson and Cooper found that the noun versions of words were longer in duration than their verb homonyms, and that these differences were due solely to their different distributions in sentences. The distributional differences between same class homonyms are likely to be smaller than those for different class homonyms, which should make them less easily distinguishable through contextually-driven acoustic modifications.
We will conclude by mentioning one implication of this work for another aspect of language use, namely linguistic humor. Puns and other jokes often rely on homonyms for their effects. The aesthetic impact of puns, in particular, requires that the audience make a temporary, but perceptible, misinterpretation of a sentence. The research of some linguists indicates that likelihood of misinterpretation will be greater with same class homonyms, and so these homonyms should be used more than different class homonyms in puns. Furthermore, the rated quality of same class homonyms should be higher than that for different class homonyms. More generally, whereas prior studies have treated homonyms equivalently in analysis and experimentation, our understanding of these words and how they are processed could be enriched by studying homonym subclasses that might differ on various dimensions such as lexical organization, language evolution, and language play.
1. Antrushina G.B., Afanasyeva O.V., Morozova N.N. English lexicology. М.: «Высшая Школа». 1985.
2. Arnold I.V. The English Word, учеб. пособие для ин-тов и фак. иностр. яз. М.: «Высшая Школа». .
3. Byron G.G., Washington P. Poems of Lord Byron.: Knopf Alfred A. .
4. Ginzburg R.S., Khidekel S.S., Knyazeva G.Y., Sankin A.A. A Course in
. Modern English Lexicology. M. .
6. Koonin A. English Lexicology M. .
7. London J. The Call of the Wild and White Fang. Prague. .
8. Maugham W.S. The Kite. In: Stories by Modern English Authors. M. .
9. Wild Oscar Two Society Comedies Norton.: W.W.S Company, Inc. .
10. Арбекова Т.И. Лексикология английского языка, учеб. пособие для ин-тов и фак. иностр. яз. М.: «Высшая Школа». .
11. Мюллер В.К. Англо-русский словарь. М. .
12. Смирницкий А.И. Лексикология английского языка. М. .
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|Этот эффект называется охлаждением атомов давлением лазерного излучения. Методы позволяющие с помощью лазерного излучения охлаждать атомы основаны на эффекте вязкой жидкости оптическая патока в которой атомы медленно перемещаются. При охлаждении вещества его энергия и энтропия понижаются поэтому процесс охлаждения возможен если энергия и энтропия излучения после взаимодействия с веществом повышаются.|
|21461.||Лазерный пинцет||957 KB|
|Сила с которой свет действует на окружающие объекты невелика но ее оказывается достаточно чтобы ловить и контролируемо перемещать частицы размером от 10 нм до 10 мкм. В дальнейшем Эшкин и его коллеги продемонстрировали возможности оптической ловушки на основе инфракрасного лазера захватывать удерживать и перемещать в пространстве различные биологические объекты такие как вирусные частицы одиночные бактериальные и дрожжевые клетки и органеллы в живых клетках водорослей. Как будет вести себя частица в поле после Пишейпера В случаях...|
|21462.||Прецизионные волоконно-оптические датчики||333 KB|
|100 Мрад Последовательного и параллельного типа Распределение температуры и деформации Обратное рассеяние Релея Интенсивность обратного рассеяния Релея Многомодовое Разрешающая способность 1 м Условия реализации волоконных датчиков связаны с наличием оптической комплектации: оптическое волокно в различных спектральных диапазонах. Соединительные и разделительные фильтры Многослойники дифракционные решетки; модуляторы интенсивности на основе электрооптического эффекта ниобат лития обладающий электрооптическими свойствами которые...|
|21463.||Импульсный оптический рефлектометр||479 KB|
|Введение Импульсные оптические рефлектометры OTDR Opticl Time Domin Reflectometer различных типов широко используются практически на всех этапах создания волоконнооптических систем связи: от производства волокна и оптического кабеля до строительства волоконнооптических линий связи ВОЛС и их эксплуатации. Измерять средние потери оптического волокна на катушках равномерность распределения потерь в волокне и выявлять наличие локальных дефектов при производстве волокна. Обнаруживать постепенное или внезапное ухудшение качества волокна...|
|21464.||Анализ современного состояния техники ранней диагностики ВОЛП||706 KB|
|Очевидно что длины волн используемые для передачи данных и для рефлектометрического контроля волокна в этом случае должны быть разными. В этой точке устанавливается оптический коммутатор OTU который по очереди включает волокна всех направлений в оптический путь сигналов рефлектометра RTU. Другой подход предполагает одновременное распространение сигнала рефлектометра по всем ответвляющимся волокнам. Согласно данным фирмы Fujikur по степени опасности для волокна можно выделить три диапазона значений его относительного удлинения.|
|21465.||Двухчастотные лазерные интерферометры||1.42 MB|
|Все оснащение лазерной измерительной головки заключающееся в системе программного и инструментального обеспечения измерения предназначено для линейных и угловые измерений измерения плоскостности измерения прямолинейности измерения взаимоперпендикулярности и измерения скорости перемещения. Дискрет измерения равен при статистической обработке сигнала fd его можно уменьшить в 10 раз. Таким образом дискретность измерения интерферометра не превышает 001 мкм. Чтобы исключить ошибку связанную с температурным расширением основания на...|