英语文体学课本11-16

1、11 The English of Science and Technology11.1 The Scope of the English of Science and Technology Our age is an age of machines, electronics and computers. With the development of science and technology, scientists and engineers exchange their ideas, discoveries and inventions, collect information and

2、 data, interpret concepts and theories, comment on the latest scientific advances and write reports based on experimental procedures, etc. Hence the need for economical, efficient and impersonal ways of expression: the English of science and technology (shortened as EST). EST is a cover term. It inc

3、ludes in its category many fields of discourse: the English of mathematics, the English of physics, the English of chemistry, the English of biology, the English of psychology, the English of linguistics, etc. The list can be extended according to how detailed we wish our investigations to be. But o

4、n the whole, the languages of all the scientific fields have such features in common that we can take them all as a single variety of English which comprises two sub-varieties: the English of specialized science and technology (ESST) and the English of common science and technology (ECST). So far as

5、 the mode is concerned, scientific English can be spoken: a lecture on science and technology, a talk between people 'speaking scientifically', a radio or television program on a science or technical subject etc; and it can be written, as scientific and technical writings, journals, academic

6、 papers, etc. The personal tenor of this variety can be less formal, as most of the spoken form of EST, or more formal as most of the written form of EST. The functional tenor of EST, however, is informative. In view of the typicalness of this variety, in this book, we shall focus on written ESST an

7、d written ECST, and point to the salient features of some spoken forms of EST. 11.2 Sample Texts for analysis For analysis of EST, we have chosen three sample texts: one is an academic thesis about the treatment of eye-disease, taken from a medical journal; another is an introduction of the methods

8、used to destroy disease germs in milk, taken from a popular science book; and the third is about how rocket propulsion is handled by impulse-momentum considerations, taken from a higher physics textbook. 1 Graves ' ophthalmopathy usually occurs in association with hyperthyroidism./ Its occasiona

9、l occurrence in the absence of thyroid disease suggests, however, that it may be a separate autoimmune disorder./ While the evidence supporting an autoimmune pathogenesis is considerable for the ophthalmopathy, it is not so impressive as that for Graves ' hyperthyroidism: orbital antibodies have

10、 not been convincingly demonstrated and auto-antigens have not been identified./ On the other hand, in patients with Graves ' ophthalmopathy the orbital tissues and eye muscle membranes are infiltrated with lymphoid cells and show evidence of cell-mediated immune reactions./ Although there is so

11、me evidence that binding of thyroid stimulating hormone fragments and thyroglobulin antithyroglobulin immune complexes to eye muscle membranes may be important in the pathogenesis of the ophthalmopathy, this needs to be confirmed./ The mechanism for the association of hyperthyroidism and ophthalmopa

12、thy is unknown, but the association likely reflects an influence of thyroid hormones on the immune system./ In view of the autoimmune pathogenesis the logical treatment of Graves ' ophthalmopathy appears to be immuno-suppression./ ( Canadian Medical Association Journal, Apri1 1, 1981 Vol . 124,

13、No . 7) 2 It has long been known to bacteria experts that the tubercle bacillus is the germ in milk which most strongly resists heat treatment./ To destroy this organism it is necessary to heat milk to about 60 for 15 minutes, and its destruction has always been taken as a way of testing the efficie

14、ncy of pasteurization./ A heat treatment of this kind destroys about 9996 of the common bacteria in milk, including nearly all those which cause milk to turn sour./ To ensure the certain destruction of tuberculosis and other disease germs in milk, it must be held at a fixed temperature for a fixed t

15、ime./ In Britain, for example, these conditions were defined by law in 1923 as 63 -66 for 30 minutes./ This became known as the 'holder' process, since the raw milk had to be pumped into a large tank, heated to just over 6 3 , held in the tank for half an hour and then pumped out and cooled.

16、/ This was a slow process and required a very cumbersome plant, so scientists worked for many years to produce a simpler, more convenient method, with less bulky equipment./ The latest method, officially approved in Britain in 1949, is known as the high-temperature- short-time, or HTST method./ It h

17、as now almost entirely replaced the 'holder' process./ In the HTST system, the milk flows continuously through many sections of thin stainless steel pipes./ During the process, the milk is held at 72 for at least 15 seconds, then, as it cools, the heat it loses is used, in part, to raise the

18、 temperature of the incoming milk in a device called a 'beet-exchanger'./3 8-7 ROCKET PROPULSION A rocket is propelled by the ejection of a portion of its mass to the rear./ The forward force on the rocket is the reaction to the backward force on the ejected material, and as more material is

19、 ejected, the mass of the rocket decreases./ The problem is best handled by impulse-momentum considerations./ In order not to bring in too many complicating forces, we shall consider a rocket fired vertically upward, and neglect air resistance and variations in g./ Figure 8-12 (a) represents the roc

20、ket at a time t after take-off, when its mass is m and its upward velocity is v./ The total momentum at this instant is thus mv./ In a short time interval dt , a mass dm of gas is ejected from the rocket./ Let v, represent the downward velocity to this gas relative to the rocket./ The velocity v'

21、; of the gas relative to the earth is then v'=v- v and its momentum is dm v'=dm(v- v,)./ At the end of the time interval dt , the mass of rocket and unburned fuel has decreased to m - dm , and its velocity has increased to v + dv./ Its momentum is therefore ( m- dm ) ( v + dv ). /Thus the to

22、tal momentum at time t + dt is ( m - dm ) ( vn + dv ) + dm ( v v ,)./ Figure 8-12 Co) represents rocket and ejected gas at this time./ We now make use of the impulse-momentum relation; the product of the resultant external force F on a system, and the time interval dt during which it acts, is equal

23、to the change in momentum of the system. / If air resistance is neglected, the external force F on the rocket is its weight - mg. (We take the upward direction as positive.)/ The change in momentum, in time dt , is the difference between the momentum of the system at the end and at the beginning of

24、the time interval./ Hence - mg d t =( m- dm )( v dv )+ dm ( v- v, ) - mv mdv-dm v, + dm dv./ The term dm dy may be dropped because it is a product of two small quantities and thus is much smaller than the other terms./ Dropping this term, dividing by dr, and rearranging, we obtain Dv= dm _ mg. (8-13

25、)./The ratio dv/dt is the acceleration of the rocket, so the left side of this equation mass times acceleration) equals the resultant force on the rocket./ The first term on the fight equals the upward thrust on the rocket, and the resultant force equals the difference between this thrust and the we

26、ight of the rocket, mg./ It will be seen that the upward thrust is proportional both to the relative velocity v, of the ejected gas and to the mass of gas ejected per unit time, dm/dt./ The acceleration is dv = v dm) g. (8-14)./ As the rocket rises, the value of g decreases, according to Newton '

27、;s law of gravitation. (In 'outer space', far from all other bodies, g becomes negligibly small.)/ If the values of v, and dm/dt remain approximately constant while the fuel is being consumed and m continuously decreases, the acceleration increases until all the fuel is burned./11.3 General

28、Features of EST The sample texts reveal some general features of EST. We are struck by the impersonal formal style and a very high concentration of technical terms and a number of mathematical symbols. This is in keeping with the specialized roles of scientists and engineers. They are interested in

29、interpreting a phenomenon 'out there' and delineating its innate laws. They endeavor to make impersonal, objective statements or observations on which all observers would agree. They are far more concerned with being accurate and concise than with giving variety to the way they express thems

30、elves. And they want to avoid any sort of misunderstanding. Hence their use of a large number of technical words, universally accepted symbols and formulae, and a formalized way of expression. Statements are commonly compressed by omitting words or parts of a sentence, or by using standard abbreviat

31、ions. Thus instead of saying The results of this experiment show that AMX significantly impairs the coordination of hand and eye.scientists might say: The AMX results show significant hand/eye coordination impairment.And the statements are usually concrete and specific. For instance, instead of The

32、results seem to be satisfactory. we have We are satisfied with the result that L (x 2 , x 1 =oAnd instead of This process greatly reduces costs. weThis process consumes 5% less fuel and turns out 12% more power. The purpose/function of a process is often put at the beginning of a sentence: To ensure

33、 the certain destruction of tuberculosis and other disease germs in milk, it must be held at a fixed temperature fur a fixed time. The results of experiments and research may be introduced by sentences beginning with the anticipatory it and using the passive: It was found that the process served two

34、 purposes. It has been shown that these specimens can only be preserved if kept at a temperature of 34 .Conventions like these are reinforced by the repeated use of sentence patterns which reflect the impersonal, objective attitude of EST writers. 11.4 Stylistic Features of EST 11.4. 1 Grammatical F

35、eatures 11.4.1 .1 More use of longer and statement-type sentences The sample texts show that compared with the varieties we have discussed, EST sentences appear a hit longer. In Sample 1, there are in all 7 sentences; the shortest one consists of 8 words, the longest 35, the average being 23.6 words

36、 per sentence. In Sample 2, the longest has 40 words, the shortest 9, the average being 23.8 words. Sample 3 is from a textbook, the longer paragraphs of which have an average of 21, 7 words per sentence. The statistics show that the sentence length in EST are longer than the sentence length in ever

37、yday conversation (8 words), or advertising (12.4 words), or some urgent kind of news reporting (20 words). The average words per sentence in EST are about the same as in public speech (which has an average of 24 words); but in EST, the sentence length does not vary as sharply as in public speech in

38、 which one sentence can have 74 words, and another may have only 4 words. This is because a mild variation in sentence length reflects the author's unemotional state of mind and his/her objective way of narrating. As is the nature of most technical writing (making statements about things and pro

39、cesses, ere), sentences in the samples are mostly of the statement type. There are often universal kinds of statements in EST texts, such as:Metals expand when heated and contract when cooled. The molecule of water has three atoms.Statements of this kind are believed to be true universally , at all

40、times and in all places. The laws of science (as Action and reaction are equal and opposite. Like charges repel each other. Unlike charges attract .), formulae equations (eg v'=v - v, F=ma ), definitions (as The gram is the mass of one cc of water.) etc are among sentences of universal statement

41、. Most of the statements are of the simple S P (O) (C) (A) structure, or A S P (C) (A) structure which presents not very much structural difficulty in understanding. Other type of sentences are possible. In Sample 3, there is one sentence in the form of a command:Let v , represent the downward veloc

42、ity of this gas relative to the rocket .A working example is customarily introduced by the following formula using command-type sentences: Consider a high pressure chamber. Imagine a charge of gas to be compressed inside that chamber. Let p 1 be the initial pressure.Such sentences are common in expe

43、rimental descriptions:Take a beaker of water and heat it over a burner. Record its temperature every minute. The temperature rises steadily until it reaches l 00 , but after that it remains constant. Now mark the side of the beaker to indicate the water level. Leave the beaker to boil for several mi

44、nutes and again record the level. Notice that some of the water has disappeared. The water is changing into water vapor. Occasionally questions may occur to draw the reader's attention to what is to follow, though we do not have any in the samples. Naturally exclamations or vocatives do not occu

45、r in this variety of English, which is supposed to be free from emotional coloring. 11.4.1 .2 Preference for impersonal sentence patterns Most highly distinctive is the frequent use of impersonal sentences, as it is important to stress the fact that experimental results will be the same as long as t

46、he experiments are replicated exactly, no matter who performs them. This is shown 1) in the use of sentences introduced by an anticipatory It ;, as inIt is obvious that these currents will generate heat in the core. It will be seen that energy cannot be destroyed; it only changes its form.and 2) in

47、the use of passive structure (with predicator in the passive voice or with passive infinitive) in narrating. Passive structures put the 'patient', or 'Goal' of the action in subject position, the Agent appearing in the optional 'by+Agent' phrase, thus allowing the 'person

48、al' aspect of the action to be removed, and the description of the experiment to appear more objective. In Sample 1 there are 7 sentences; 4 of them contain passive structure. Out of the 12 sentences in Sample 2, 8 sentences have passive structure. As is shown in the samples, the personal agent

49、is normally not mentioned, though occurrence of other agents are possible in EST, such as ways of doing things (as in: Electricity can be transmitted by means of wires ), plants or substances (as in: The turbines are driven by steam ), organizations (as in: Large quantities of fuel are used by moder

50、n industry ), natural processes or circumstances (as in: The failure of the pipe was caused by corrosion ). 11. 4.1 .3 Wide use of non-finite structure and prepositional phrases Scientists and engineers often want to express what they mean clearly in the least possible words. So they often shorten t

51、heir sentences by using non-finite structure or prepositional phrases in place of corresponding clauses. For example:When they are heated under pressure, the constituents fuse together. is shortened toWhen heated under pressure the constituents fuse together.or even toHeated under pressure the const

52、ituents fuse together. A good many infinitive phrases are often used to express purpose, object or aim; as in To destroy this organism it is necessary to heat milk to about 60 for 15 minutes.and function; as in The pedal serves to operate the clutch .Participle phrases are often used to replace adve

53、rbial clauses: Dropping this term, dividing by dt , and rearranging, we obtain m= v g.or to replace a relative clause: While the evidence supporting an autoimmune pathogenesis. . The part played by civil engineers in pioneering work . Sometimes a prepositional phrase is used to replace a relative cl

54、ause; as in:All passengers (who were) on board the ship had to pass a medical examination. Steels with (=which have) a carbon content of between 0.5 and 1.3% are known as high carbon steels. After finishing the experiments , we wrote down the results. 11.4.1 .4 Use of expanded pre-modification Nomin

55、al groups in EST are characterized by expanded noun pre-modification. In the samples there are some examples: eye muscle membranes, thyroid stimulating hormone fragments, thyroglobulin antithyroglobulin immune complexes, other disease germs, the high-temperature- short-time, or HTST method, thin sta

56、inless steel pipes, the impulse-momentum relation, the resultant external force F , etc. This is evidently for direct and economical expression. Take the following for example:advanced gas turbine generator (=an electrical generator of advanced design driven by gas turbines) considerably lower boili

57、ng point (=point at which a substance boils which is considerably lower than some other points referred to) 11.4.1 .5 Tendency to nominalization Nominalization (chiefly of predicate transitive verbs) is another way of making sentences compact, impersonal and formal. In EST, there are many examples o

58、f this. Thus instead of The contents of the tank are discharged by a pump.technical writers say Discharge of the contents of the tank is effected by a pump.And instead of If a potential is applied to gas at low pressure, ionization of the molecules will result.they sayThe application of a potential

59、to gas at low pressure will result in ionization of the molecules.Similarly, we have Allowance should be made for expansion or contraction of the shaft. Analysis of these methods will be made in a later section of the book. Nominalization even occurs with predicatives. See how the following sentence It is necessary to examine whether the new design is efficient.is changed toIt is necessary to examine the efficiency of the new de